The selection of the best point level or liquid level sensor to monitor the inventory of valuable liquid, powder and solid chemicals is a challenging task. However, by means of customization options, it is possible to design the sensor that matches the specifications of the inventory measurement.
With the availability of different kinds of sensors and a number of options, the decision-making and product-specification processes become extremely difficult. The utility of a level measurement sensor in a specific application can be optimized with a customized level sensor.
The following devices have more options to manufacture a device based on users’ specifications:
Ultrasonic level sensors
Magnetostrictive sensors
Pressure transducers
Tilt switches
Diaphragm switches
Vibrating rods
Capacitance probes
Rotaries
These sensors show promise in providing precise and repeatable level detection. However, each sensor will achieve its optimal performance level when designed for a particular application. Customized point level indicators will provide the best solution depending on whether the vessels have corrosive materials, sanitary regulations, high temperatures, thick walls or any one of the many specifications.
Rotaries
Rotary level indicators are designed for high, mid and low-level detection applications in tanks, bins or other vessels carrying bulk solids and powder. They are linked to an alarm panel or combined to a PLC. As the contents of the tank achieve a specific limit, the indicators are programmed to transmit audible or visual alerts. These alarms prevent overfilling or depletion of tank which could be an expensive and unwanted outcome of incapable level monitoring system.
It is possible to customize inventory management to each vessel using galvanized or stainless steel extension options. Vertical rotaries are suitable for applications where the rotary is operated as a high-level alarm. Most of the operators avoid filling the vessels completely and leave a certain amount of headroom. It is possible to overcome this situation by using a customized shaft length that is adjusted according to the desired amount of headroom. An alert will be sent by a rotary shaft customized for high-level detection as the material achieves the desired limit so as to prevent bin overfill.
In order to address the issues related to lump material level measurement, another extension option is manufactured. Flexible shaft rotaries are suitable for high level detection in heavy materials or other lump solids. In all these cases, heavy materials tend to damage a rigid extension. A flexible cable in place of a fixed solid shaft extension is linked to the rotary and mounted on top of the vessel. With its extra movement capabilities, the rotary can detect high levels under a complex condition without bending a rigid rotary extension shaft.
Horizontal rotary extensions can be used to provide a clear structure of the shaft and paddle in case the vessel carrying the material to be measured has thick bin walls, including a concrete silo that allows the rotary to perform its task. Horizontal extensions allow the side-mounted rotaries to carry out high, mid or low-level detection in a vessel. This design enables the rotary to be attached via the side of a bin wall, thereby minimizing the damage risk during operation.
Adjustable top mounted rotaries can be used to place varying material levels in a bin or silo as they allow convenient changes without replacing the device or entering the bin. They are mounted on top of the bin, and include an adjustable coupling capable of moving up and down the shaft length. With this movement, the rotary can accommodate material levels that are subjected to changes.
A mini-rotary is the best choice for level measurement in smaller bins or hoppers with confined space. The small size of the mini- rotary designed to control material levels in compact spaces enables it to operate in an environment where other devices may not fit easily. The small, mini-rotaries have a rugged design and can deal with a number of light to heavy materials. The motor is mounted on the top or side of a bin, and can rotate when there is no material. With the increase in the material level, the operator is alerted by the sound from an alarm.
Fail-safe rotary level indicators are provided with a sophisticated technology where a system alerts the power loss, and motor/electronics failure in addition to monitoring vessel levels. This type of rotary is one of the best choices for applications that demand continuous operation, thanks to its progressive fail-safe capabilities. This is also preferred when operators need to constantly keep a track on the unit’s status. These rotaries ideal for a wide range of bulk solids, and can either be mounted on the top or side of the vessels.
In the presence of corrosive materials, a stainless steel process connection can be used along with a rotary so as to ensure a prolonged service life of the device and more precise measurement. Rotaries with the connection are designed such that all the materials that make contact with the bin are stainless steel. This ensures that stainless steel process connections are ideal for food and pharmaceutical applications with sanitary needs. It is also ideal for rugged applications, such as those that involve caustic or corrosive materials.
A heat tube can be included to distance electronics that are far away from the heat source when external temperatures outside the bin become higher. Heat tubes are attached to the top or side mounted rotaries in environments with elevated temperatures. Using these tubes, the rotary can be extended beyond insulation on the outside of a vessel.
Rotary customization options include:
Heat tubes
Stainless steel process connections
Fail-safe rotaries
Mini rotaries
Adjustable top mount rotaries
Horizontal rotary extensions
Flexible shaft rotaries
Vertical rotaries
The rotary device can be further customized by choosing one of the many paddle options, besides a myriad of rotary extensions and custom fittings. This also ensures high performance of the device. An appropriate selection of paddle will enhance the rotary’s function irrespective of the measurement of the levels of light or heavy material.
In order to achieve the suitable fit for each vessel, the diameter of the options for single blade, double blade, three-vane and bayonet style paddles is varied. Collapsible rotary paddles are available to avoid the entry of personnel into the bins. The paddles are made up of stainless steel or nylon, and are attached to the top and side mounted rotary level indicators.
ISweek（http://www.isweek.com/）- Industry sourcing & Wholesale industrial products
2016年6月30日星期四
A novel air flow sensor from printed PEDOT micro-hairs
We report the creation of a low flow rate air flow sensor from PEDOT
micro-hairs. The hairs are printed as pipette-defined depositions using a
nanopositioning system. The printing technique was developed for fabricating
structures in 2D and 3D.
Here micro-hairs with diameters of 4.4 μm were
repeatedly extruded with constant heights. These hairs were then applied to
produce a prototype flow rate sensor, which was shown to detect flows of
3.5 l min−1.
Structural analysis was performed to demonstrate that the
design can be modified to potentially observe flows as low as
0.5 l min−1. The results are extended to propose a
practical digital flow rate sensor.
Global Advanced CO2 Sensor Market 2015 – 2019, New Report Launched
Advanced CO2 sensors help to monitor the intensity of CO2 in
different mediums like air or water and can adjust automatically to changes in
temperature, humidity, and altitude. This market is an integral part of the
global sensors market and is heavily influenced by the augmented demand for
location-based advanced CO2 sensors, which results in its impressive CAGR of
nearly 42% by 2019.
The market research analyst has estimated eminent trends, such as the rising need for better air pollution measurement systems, to drive market growth during the forecast period. Recent innovations in the electronic industry have resulted in the increased emission of hazardous gases, which leads to global warming. Therefore, in order to effectively measure and monitor the intensity of CO2 in the atmosphere, environmental scientists across the globe are increasingly adopting advanced CO2 sensors.
Segmentation by type and analysis of the advanced CO2 sensors market
- NDIR CO2 sensors
- Chemical CO2 sensors
In this market analysis, analysts estimate the non-dispersive infrared (NIDR) CO2 sensors segment to account for nearly 89% of the total market share by 2019. The long lifespan, stability, and high humidity and dirt-withstanding nature of IR sensors are responsible for its high market share during the forecast period.
Geographical segmentation of the advanced CO2 sensors market
- APAC
- EMEA
-Americas
In terms of revenue contribution, the EMEA region is expected to dominate this market during the forecast period followed by theAmericas
Competitive landscape and key vendors
This global advanced CO2 sensors market is highly fragmented as most of the vendors in this market are yet to establish themselves as prominent players with extensive product offerings. Since this market is still in its nascent stage, analysts estimate intense competition between vendors to drive market growth during the forecast period.
Key vendors in this market are -
- Digital Control Systems
- GE
- Honeywell
- Johnson Controls
Other prominent vendors analyzed in this market study are AirTest Technologies, Balluff GmbH, Balluff GmbH, Pepperl+Fuchs GmbH, SICK AG, Siemens Industry, SenseAir AB, Hans Turck GmbH & Co. KG, Vaisala Inc., and Veris Industries Inc.
Key questions answered in the report include
- What will the market size and the growth rate be in 2019?
- What are the key factors driving the global advanced CO2 sensors market?
- What are the key market trends impacting the growth of the global advanced CO2 sensors market?
- What are the challenges to market growth?
- Who are the key vendors in the global advanced CO2 sensors market?
- What are the market opportunities and threats faced by the vendors in the global advanced CO2 sensors market?
- Trending factors influencing the market shares of the EMEA,Americas
- What are the key outcomes of the five forces analysis of the global advanced CO2 sensors market?
Spanning over 58 pages and 25 Exhibit "Global Advanced CO2 Sensor Market 2015 - 2019" report covers Executive summary, Scope of the report, Market research methodology, Introduction, Market Overview, Market Landscape, Market segmentation, Geographical segmentation, Impact of drivers, Impact of drivers and challenges, Vendor landscape, Key vendor analysis, Appendix.
The market research analyst has estimated eminent trends, such as the rising need for better air pollution measurement systems, to drive market growth during the forecast period. Recent innovations in the electronic industry have resulted in the increased emission of hazardous gases, which leads to global warming. Therefore, in order to effectively measure and monitor the intensity of CO2 in the atmosphere, environmental scientists across the globe are increasingly adopting advanced CO2 sensors.
Segmentation by type and analysis of the advanced CO2 sensors market
- NDIR CO2 sensors
- Chemical CO2 sensors
In this market analysis, analysts estimate the non-dispersive infrared (NIDR) CO2 sensors segment to account for nearly 89% of the total market share by 2019. The long lifespan, stability, and high humidity and dirt-withstanding nature of IR sensors are responsible for its high market share during the forecast period.
Geographical segmentation of the advanced CO2 sensors market
- APAC
- EMEA
-
In terms of revenue contribution, the EMEA region is expected to dominate this market during the forecast period followed by the
Competitive landscape and key vendors
This global advanced CO2 sensors market is highly fragmented as most of the vendors in this market are yet to establish themselves as prominent players with extensive product offerings. Since this market is still in its nascent stage, analysts estimate intense competition between vendors to drive market growth during the forecast period.
Key vendors in this market are -
- Digital Control Systems
- GE
- Honeywell
- Johnson Controls
Other prominent vendors analyzed in this market study are AirTest Technologies, Balluff GmbH, Balluff GmbH, Pepperl+Fuchs GmbH, SICK AG, Siemens Industry, SenseAir AB, Hans Turck GmbH & Co. KG, Vaisala Inc., and Veris Industries Inc.
Key questions answered in the report include
- What will the market size and the growth rate be in 2019?
- What are the key factors driving the global advanced CO2 sensors market?
- What are the key market trends impacting the growth of the global advanced CO2 sensors market?
- What are the challenges to market growth?
- Who are the key vendors in the global advanced CO2 sensors market?
- What are the market opportunities and threats faced by the vendors in the global advanced CO2 sensors market?
- Trending factors influencing the market shares of the EMEA,
- What are the key outcomes of the five forces analysis of the global advanced CO2 sensors market?
Spanning over 58 pages and 25 Exhibit "Global Advanced CO2 Sensor Market 2015 - 2019" report covers Executive summary, Scope of the report, Market research methodology, Introduction, Market Overview, Market Landscape, Market segmentation, Geographical segmentation, Impact of drivers, Impact of drivers and challenges, Vendor landscape, Key vendor analysis, Appendix.
Turkish coal mine disaster could have been avoided with methane sensors
A recent incident of methane poisoning in a mine in Turkey caused the
deaths of mine workers, highlighting once again the dangers of
underground coal mining.If they have used the methane sensors, the
disaster can be avoided finally.
Considered one of the most dangerous work environments in the world, underground mines expose workers to extreme temperatures and confined spaces, both factors taking a heavy toll on any miner.
However, methane gas is another risk present down the shaft of a mine. A naturally occurring substance, methane gas is released as part of the coal mining process. But the gas is dangerous and potentially lethal without the proper detection and protective equipment.
In the Turkish incident, 18 workers were trapped in the coal mine near Ermenek, in the Turkish province of Karaman last October. Mine rescue teams were unable to enter the entry point for a number of days due to flooding. When the water subsided, emergency services could get to some of the men.
After 10 days in the flooded underground conditions, two miners were found dead. Mine rescue teams pulled out another eight after an additional 12 days. Though the deaths were initially attributed to drowning due to the flooded shaft, the hospital autopsy pointed to methane gas as the killer.
There are also grave fears for the eight miners who are still trapped down the mine. Due to increasing levels of carbon dioxide and a lack of oxygen, it has been impossible to reach them. The arrival of winter in the area has also hampered rescue attempts due to snow.
Underground mines typically install methane detectors and refuge chambers to combat methane gas levels. People can survive for up to 30 days inside a refuge chamber while waiting for emergency services to arrive. Instead the miners were found huddled close to each other against a section of the mine as they tried to escape the fumes.
Mining and other professions in similarly dangerous environments require businesses to be up-to-speed on workplace safety and also install the best gas detector equipment available.
In addition to refuge chambers, businesses could introduce devices such as the testo 316-1 methane gas detectors, which are capable of locating the smallest leaks of methane, and can be hooked on to the workers’ belt. An optional TopSafe case protects the device from dirt and impacts belowground.
ISweek（http://www.isweek.com/）- Industry sourcing & Wholesale industrial products
Considered one of the most dangerous work environments in the world, underground mines expose workers to extreme temperatures and confined spaces, both factors taking a heavy toll on any miner.
However, methane gas is another risk present down the shaft of a mine. A naturally occurring substance, methane gas is released as part of the coal mining process. But the gas is dangerous and potentially lethal without the proper detection and protective equipment.
In the Turkish incident, 18 workers were trapped in the coal mine near Ermenek, in the Turkish province of Karaman last October. Mine rescue teams were unable to enter the entry point for a number of days due to flooding. When the water subsided, emergency services could get to some of the men.
After 10 days in the flooded underground conditions, two miners were found dead. Mine rescue teams pulled out another eight after an additional 12 days. Though the deaths were initially attributed to drowning due to the flooded shaft, the hospital autopsy pointed to methane gas as the killer.
There are also grave fears for the eight miners who are still trapped down the mine. Due to increasing levels of carbon dioxide and a lack of oxygen, it has been impossible to reach them. The arrival of winter in the area has also hampered rescue attempts due to snow.
Underground mines typically install methane detectors and refuge chambers to combat methane gas levels. People can survive for up to 30 days inside a refuge chamber while waiting for emergency services to arrive. Instead the miners were found huddled close to each other against a section of the mine as they tried to escape the fumes.
Mining and other professions in similarly dangerous environments require businesses to be up-to-speed on workplace safety and also install the best gas detector equipment available.
In addition to refuge chambers, businesses could introduce devices such as the testo 316-1 methane gas detectors, which are capable of locating the smallest leaks of methane, and can be hooked on to the workers’ belt. An optional TopSafe case protects the device from dirt and impacts belowground.
ISweek（http://www.isweek.com/）- Industry sourcing & Wholesale industrial products
Wadeco MWS-ST/SR type microwave sensor for blocked chute detection
As well as its use for level detection, microwave technology is now
being applied across many industries for applications such as the
detection of blocked chutes, flow/no-flow detection, the detection of
product on conveyors, the detection of blocked pneumatic conveying pipes
and the detection of blocked air slides.
The Wadeco MWS-ST/SR-type microwave sensor is a switch consisting of a transmitter (MWS-ST) and a receiver (MWS-SR) installed face to face. The transmitter emits a continuous, low-power microwave beam towards the receiver and an output relay is released when the beam is obstructed.
With the microwave sensor’s non-invasive installation methods, there is no disruption to material flow and the process can be kept closed. Microwave sensors are also unaffected by build-up on the antenna head, due to the high penetrability of microwaves. With the series 3, the range can now extend up to 200 m.
Microwave sensors are also unaffected by environmental conditions including heavy dust and airborne particles, smoke, vapour, flames, rain, snow etc.
Microwave sensors have a wide application across all areas of industry where highly reliable, non-contact detection is required. They are generally used for process control by monitoring presence/absence of product, flow/no flow conditions and point-level detection in bins and silos.
With no moving parts and non-contact detection, the result is reduced wear and tear, zero maintenance and added safety for personnel and operators.
ISweek（http://www.isweek.com/）- Industry sourcing & Wholesale industrial products
The Wadeco MWS-ST/SR-type microwave sensor is a switch consisting of a transmitter (MWS-ST) and a receiver (MWS-SR) installed face to face. The transmitter emits a continuous, low-power microwave beam towards the receiver and an output relay is released when the beam is obstructed.
With the microwave sensor’s non-invasive installation methods, there is no disruption to material flow and the process can be kept closed. Microwave sensors are also unaffected by build-up on the antenna head, due to the high penetrability of microwaves. With the series 3, the range can now extend up to 200 m.
Microwave sensors are also unaffected by environmental conditions including heavy dust and airborne particles, smoke, vapour, flames, rain, snow etc.
Microwave sensors have a wide application across all areas of industry where highly reliable, non-contact detection is required. They are generally used for process control by monitoring presence/absence of product, flow/no flow conditions and point-level detection in bins and silos.
With no moving parts and non-contact detection, the result is reduced wear and tear, zero maintenance and added safety for personnel and operators.
ISweek（http://www.isweek.com/）- Industry sourcing & Wholesale industrial products
Why Apple's Next iPhone May Include A Barometer Sensor
The iPhone already comes packed with barometer sensors, but a new report
from 9to5Mac’s Mark Gurman says this year’s model might come with yet
another sensor that’s commonly used to measure temperature, air
pressure, and altitude.
That’s right. Gurman believes this year’s iPhone may feature a barometer for the first time.
The references to a barometer in an upcoming iPhone were discovered by FutureTap developer Ortwin Gentz, who discovered frameworks dedicated to “altitude tracking” within a version of Xcode 6 for iOS 8, the second beta for which was released Tuesday.
Gentz said he tried testing the framework with an iPhone 5S but the hardware would not accept or support the new framework; 9to5Mac tried a similar test of the framework, which only seemed to confirm Gentz’s findings.
In other words, the new tracking functionality must be written for a yet-to-be-released Apple device — or devices. Since the barometer reference was buried within the code for iOS 8, it’s possible any barometer-related features could be included in the next iPhone or next iPads. It could even be integrated into Apple’s upcoming smartwatch project, which will reportedly release in October.
Furthermore, it also seems like the barometer will play a big role in ambient pressure tracking, which helps determine weather pressure as well as altitude. Since a barometer can read air pressure to determine if it’s going to be sunny or stormy, the inclusion of this sensor could open up the potential for third-party applications to leverage the sensor for things like mapping, location tracking, and crowdsourcing of weather data.
In general, a barometer could give iPhone users a better idea of their surroundings without needing to rely on third-party weather apps or an internet connection — both of which can be unreliable at times. By giving more-precise information about a user's immediate environment, Apple and other developers could potentially create applications that crowdsource this air pressure data to deliver more-accurate and useful feedback.
So where would the barometer go? Considering how the M7 motion co-processor in the iPhone 5s houses the phone's accelerometer, gyroscope, and compass — also assisting the main A7 chipset with the computing load — Gurman believes the next iPhone will bury the barometer inside an M8 co-processor, thus allowing the 64-bit A8 chip more freedom to handle intensive tasks and applications.
While Apple has never included a barometer in any of its mobile devices thus far, there are several Android handsets that include the sensor, including the Motorola Xoom and Samsung’s popular Galaxy Nexus. The iPhone has several other sensors, including an ambient light sensor, an accelerometer, a proximity sensor, a magnetometer, and most recently, the gyroscope was added in 2010 for the release of the iPhone 4S.
Besides the possible barometer, we believe Apple’s next iPhone — presumably called “iPhone 6” — will feature a sharper display made of sapphire glass and a thinner and rounder form factor. Most reports also say the next iPhone will feature a bigger screen, though some have said Apple will actually release two large-screened models measuring 4.7 inches and 5.5 inches. The current iPhone 5S and 5C models both feature 4-inch screens.
ISweek（http://www.isweek.com/）- Industry sourcing & Wholesale industrial products
That’s right. Gurman believes this year’s iPhone may feature a barometer for the first time.
The references to a barometer in an upcoming iPhone were discovered by FutureTap developer Ortwin Gentz, who discovered frameworks dedicated to “altitude tracking” within a version of Xcode 6 for iOS 8, the second beta for which was released Tuesday.
Gentz said he tried testing the framework with an iPhone 5S but the hardware would not accept or support the new framework; 9to5Mac tried a similar test of the framework, which only seemed to confirm Gentz’s findings.
In other words, the new tracking functionality must be written for a yet-to-be-released Apple device — or devices. Since the barometer reference was buried within the code for iOS 8, it’s possible any barometer-related features could be included in the next iPhone or next iPads. It could even be integrated into Apple’s upcoming smartwatch project, which will reportedly release in October.
Furthermore, it also seems like the barometer will play a big role in ambient pressure tracking, which helps determine weather pressure as well as altitude. Since a barometer can read air pressure to determine if it’s going to be sunny or stormy, the inclusion of this sensor could open up the potential for third-party applications to leverage the sensor for things like mapping, location tracking, and crowdsourcing of weather data.
In general, a barometer could give iPhone users a better idea of their surroundings without needing to rely on third-party weather apps or an internet connection — both of which can be unreliable at times. By giving more-precise information about a user's immediate environment, Apple and other developers could potentially create applications that crowdsource this air pressure data to deliver more-accurate and useful feedback.
So where would the barometer go? Considering how the M7 motion co-processor in the iPhone 5s houses the phone's accelerometer, gyroscope, and compass — also assisting the main A7 chipset with the computing load — Gurman believes the next iPhone will bury the barometer inside an M8 co-processor, thus allowing the 64-bit A8 chip more freedom to handle intensive tasks and applications.
While Apple has never included a barometer in any of its mobile devices thus far, there are several Android handsets that include the sensor, including the Motorola Xoom and Samsung’s popular Galaxy Nexus. The iPhone has several other sensors, including an ambient light sensor, an accelerometer, a proximity sensor, a magnetometer, and most recently, the gyroscope was added in 2010 for the release of the iPhone 4S.
Besides the possible barometer, we believe Apple’s next iPhone — presumably called “iPhone 6” — will feature a sharper display made of sapphire glass and a thinner and rounder form factor. Most reports also say the next iPhone will feature a bigger screen, though some have said Apple will actually release two large-screened models measuring 4.7 inches and 5.5 inches. The current iPhone 5S and 5C models both feature 4-inch screens.
ISweek（http://www.isweek.com/）- Industry sourcing & Wholesale industrial products
2016年6月29日星期三
CO2 sensor versus volatile organic compounds (VOC) sensor
The study investigated performance of two commercially
available non-selective metal oxide semiconductor VOC sensors and two
commercially available non dispersive infrared CO2 sensors installed in one
person office. The office was equipped with demand controlled ventilation.
The signals from VOC and CO2 sensors, presence detection
sensor and supply/return air flow were logged. VOC and CO2 signals were in
agreement with respect to indicated need for mechanical ventilation for 49 % of
occupied time (81 % of whole measuring period).
VOC measurement would clearly trigger the mechanical
ventilation in contradiction with CO2 measurement in 11 % of occupied time.
Opposite situation was observed in 6 % of occupied time. In approx. 22 % of
occupied time CO2 signal has just reached the set-point while the VOC signal
was significantly below. In that case the ventilation start up would be
dependent on settings of a particular controller.
Smart Microwave Sensors For Critical Site Protection
Sensitive and
protected area such as oil fields, power plants, airports, borders, ports,
embassies, military and government sites, correctional facilities, industrial
and commercial installations, and VIP residences are critical sites that
necessitate very efficient protection against criminal or terroristic attacks.
The classic protection systems commonly used for infrastructure protection, such as barbed wire fences and perimeter security microwave sensors with a low level of smartness and flexibility, are often highly obtrusive and not definitively unassailable. A clever solution to many of the drawbacks associated with security devices currently on the market, most of which are based on cameras, could consist of a wireless sensor network (WSN) of smart radar sensors (SRS) with a high level of reconfigurability and robustness to physical and cyber-attacks.
Innovative technologies are moving toward highly miniaturized and integrated radar sensors suitable to be easily embedded or concealed in the site protection infrastructure.
SRS networks are capable of detecting multiple intruder simultaneously and allow fully radar detection capability in all light and weather conditions along with continuous tracking of each detected target. Furthermore, the classification of the target and then of the intruder (armed or disarmed) will be facilitated using polarization agility and artificial neural network methods.
The classic protection systems commonly used for infrastructure protection, such as barbed wire fences and perimeter security microwave sensors with a low level of smartness and flexibility, are often highly obtrusive and not definitively unassailable. A clever solution to many of the drawbacks associated with security devices currently on the market, most of which are based on cameras, could consist of a wireless sensor network (WSN) of smart radar sensors (SRS) with a high level of reconfigurability and robustness to physical and cyber-attacks.
Innovative technologies are moving toward highly miniaturized and integrated radar sensors suitable to be easily embedded or concealed in the site protection infrastructure.
SRS networks are capable of detecting multiple intruder simultaneously and allow fully radar detection capability in all light and weather conditions along with continuous tracking of each detected target. Furthermore, the classification of the target and then of the intruder (armed or disarmed) will be facilitated using polarization agility and artificial neural network methods.
The Alcowatch wristwatch alcohol tester
August 9, 2006 Alcohol tester and road-use don’t mix, and tens of thousands of
human beings a year are maimed or killed due to alcohol-impaired
drivers. So if you’re regularly going to drink and drive, which many of
us do, then the very least you can do as a responsible human being is to
ensure your blood alcohol content is below the legal limit.
We’ve already written up the fascinating stand-alone Sobercheck breathalyser and we recently wrote about the LG Breathalyzer mobile phone. Well now there’s a wristwatch with a built-in breathalyser set to hit the market later this month. So die-hard booze hounds now can have their very own breathalyser on the end of their arm to ensure the only person they kill is themselves.
Manufactured and distributed by A&A Products of Hong Kong, which makes a range of breathalyser and Breath Alcohol Ignition Interlock Devices (BAIIDs) plus some real oddities such as a waterproof MP3 players and waterproof radios, Milk Bottle Thermometers and infrared thermometers, the wristwatch alcohol tester not only includes a breathalyser, it also reads ambient temperature and is expected to retail for under US$100. A&A is seeking international distributors and enquiries should be directed here.
ISweek（http://www.isweek.com/）- Industry sourcing & Wholesale industrial products
We’ve already written up the fascinating stand-alone Sobercheck breathalyser and we recently wrote about the LG Breathalyzer mobile phone. Well now there’s a wristwatch with a built-in breathalyser set to hit the market later this month. So die-hard booze hounds now can have their very own breathalyser on the end of their arm to ensure the only person they kill is themselves.
Manufactured and distributed by A&A Products of Hong Kong, which makes a range of breathalyser and Breath Alcohol Ignition Interlock Devices (BAIIDs) plus some real oddities such as a waterproof MP3 players and waterproof radios, Milk Bottle Thermometers and infrared thermometers, the wristwatch alcohol tester not only includes a breathalyser, it also reads ambient temperature and is expected to retail for under US$100. A&A is seeking international distributors and enquiries should be directed here.
ISweek（http://www.isweek.com/）- Industry sourcing & Wholesale industrial products
Miniature Mass Flow Sensor
Market demand for a miniature mass flow sensor for tight packaging
applications such as pick & place equipment with multiple heads
drove Omron to take its proven MEMS sensor technology and successfully
repackage it into a smaller envelope. The resulting product, the
D6F-03A3 is a unidirectional MEMS mass flow sensor in the desired
compact, streamlined body.
The D6F-03 series operates on a supply voltage of 10.8 to 26.4VDC while consuming just 15mA maximum. Their output signal is analog, 1 to 5VDC with load resistance of 10k Ohms minimum. The case is composed of molded thermoplastic and aluminum alloy with a three-pin industry standard electrical connector.
There are many applications utilizing these devices including pick & place systems, leak detection, spectroscopy, mass flow controllers, test equipment, and fuel cells.
Engineering samples and a complete set of technical data are available by contacting Omron Electronic Components.
ISweek（http://www.isweek.com/）- Industry sourcing & Wholesale industrial products
The D6F-03 series operates on a supply voltage of 10.8 to 26.4VDC while consuming just 15mA maximum. Their output signal is analog, 1 to 5VDC with load resistance of 10k Ohms minimum. The case is composed of molded thermoplastic and aluminum alloy with a three-pin industry standard electrical connector.
There are many applications utilizing these devices including pick & place systems, leak detection, spectroscopy, mass flow controllers, test equipment, and fuel cells.
Engineering samples and a complete set of technical data are available by contacting Omron Electronic Components.
ISweek（http://www.isweek.com/）- Industry sourcing & Wholesale industrial products
Toshiba Matsushita Display Develops Photosensor Touch-Panel
Toshiba Matsushita Display Technology Co., Ltd. (TMD) has developed an
LCD panel that enables finger-touch input using photosensors under a
range of light conditions from dark indoor to bright outdoor. Through
enhanced sensitivity of the photosensors integrated onto the LCD panel's
glass substrate and optimized signal processing functions, the panel
detects reflection from a finger using backlight in dark indoor and
finger shadows using external light in bright outdoor.
The prototyped panel is a transmissive LCD panel using a 2.8-inch (7.1 cm diagonal) WQVGA (400 x 240 pixels) resolution, low-temperature polycrystalline Si (p-Si) TFT with approximately 65,000 display colors. The range of ambient light intensity, in which finger-touch input is available, extends from 0 to 100,000 lx.
The panel has become able to recognize finger-touch input in a wide range of light intensity by switching its recognition modes between finger shadows using external light and finger reflections using its built-in backlight depending on the situation. The panel not only recognizes finger shadows but also supports input using an optic pen. TMD will present this panel at the Flat Panel Display International (Display 2007) show to be held at Tokyo Big Sight from April 11 to 13.
ISweek（http://www.isweek.com/）- Industry sourcing & Wholesale industrial products
The prototyped panel is a transmissive LCD panel using a 2.8-inch (7.1 cm diagonal) WQVGA (400 x 240 pixels) resolution, low-temperature polycrystalline Si (p-Si) TFT with approximately 65,000 display colors. The range of ambient light intensity, in which finger-touch input is available, extends from 0 to 100,000 lx.
The panel has become able to recognize finger-touch input in a wide range of light intensity by switching its recognition modes between finger shadows using external light and finger reflections using its built-in backlight depending on the situation. The panel not only recognizes finger shadows but also supports input using an optic pen. TMD will present this panel at the Flat Panel Display International (Display 2007) show to be held at Tokyo Big Sight from April 11 to 13.
ISweek（http://www.isweek.com/）- Industry sourcing & Wholesale industrial products
2016年6月28日星期二
Beam extrapolation and photosensor testing for the T2K experiment
Our understanding of the physics of neutrino oscillations
has evolved rapidly over the past decade or so, with results from the SNO,
Super-K, MINOS and CHOOZ experiments, among others, producing results favouring
a three-neutrino mixing model, and significantly constraining the parameter
space for the mixing.
There are still several important questions to be answered
however: we do not know whether theta_13 is non-zero, or whether (sin^2 (2*theta_23))
is maximal; also, we do not know the sign of the mass splitting Delta M^2, or
whether CP-violation occurs in the lepton sector. The latter is possibly the
most exciting of all - leptonic CP-violation is a requirement for leptogenesis,
and could therefore indicate a solution to the matter-antimatter asymmetry
problem in cosmology. The T2K long-baseline neutrino experiment is one of a new
generation of neutrino projects, which will make more precise measurements of
theta_13 and theta_23 than has been achieved by previous experiments. It uses
the Super-K water Cerenkov detector at Kamioka as a far detector, and also has
a suite of new near detectors.
These are largely scintillator-based, but use a novel
photosensor, the silicon photomultiplier (SiPM), for light readout. T2K has
been leading the effort understand and model these new sensors, and the present
work will describe the current state-of-the-art in device characterisation, and
also the effort to ensure the quality of the devices installed in the
calorimeter of the ND280 near detector. An important part of a long-baseline
analysis is the extrapolation of the neutrino flux measured at the near
detector to predict that at the far detector. Methods to do this have been
developed by previous experiments; however T2K uses an innovative configuration
whereby the main detectors are displaced from the neutrino beam centre,
removing much of the high-energy tail in the neutrino flux to reduce
backgrounds from non-quasielastic events. This thesis evaluates the
effectiveness of two extrapolation techniques, used by previous experiments,
for the T2K configuration.
The positive attraction of a non-magnetic CO2 sensor
In
typical pioneering style Analox
recently completed a highly specialised research project on behalf of a major
military supplier. The goal was to develop a carbon dioxide (CO2)
sensor with an extremely low magnetic signature – a technology currently
unavailable in off-the-shelf products. The initial results were promising and
the resulting prototype fulfilled the required specification.
The availability of such a sensor would enable the production of gas-detection systems with a magnetic signature not larger than 5nT (nano Tesla), the limit specified by the NATO Standardization Agreement STANAG 2897 Class A. Compliance with this standard is becoming an operational necessity for defence applications which deal with magnetically sensitive ordnance.
The focus of Analox’s commissioned research was the feasibility of a non-magneticCO2 sensor for use in re-breathers. A re-breather is a type of self-contained breathing apparatus designed to permit ‘recycling’ of exhaled air, by removing excess carbon dioxide and gradually replacing the depleted oxygen.
Re-breathers incorporate both an oxygen tank and a canister of soda lime which absorbs, or ‘scrubs’ the carbon dioxide from the exhaled air. This canister must be physically repacked with absorbent material before use but the process has been known to fail. Any deficiencies in either the packing process or the quality of the absorbent may result in potentially fatal CO2 poisoning, known as hypercapnia.
The dangers of hypercapnia are well-documented. Consequently strict procedures exist wherever divers or emergency personnel are responsible for checking and repacking soda lime canisters for re-breathers. Nevertheless the physical nature of the task remains vulnerable to poor maintenance or human error.
Safety is greatly enhanced by the integration of a CO2 sensor in the re-breather. This provides an early warning of any increase in CO2 and gives the user valuable time to take action. For re-breathers that are not required to be anti-magnetic, this solution is relatively simple. However, re-breathers that are specified to comply with STANAG 2897 Class A would be compromised by the use of an off-the-shelf CO2 sensor which has a typical (i.e. relatively high) magnetic signature.
Before Analox’s prototype sensor is put into production further tests will be performed to prove its ongoing accuracy and reliability. And whilst details of the technologies involved are commercially sensitive, it is fair to say that the non-magnetic CO2 sensor offers many advantages over those currently available.
The availability of such a sensor would enable the production of gas-detection systems with a magnetic signature not larger than 5nT (nano Tesla), the limit specified by the NATO Standardization Agreement STANAG 2897 Class A. Compliance with this standard is becoming an operational necessity for defence applications which deal with magnetically sensitive ordnance.
The focus of Analox’s commissioned research was the feasibility of a non-magneticCO2 sensor for use in re-breathers. A re-breather is a type of self-contained breathing apparatus designed to permit ‘recycling’ of exhaled air, by removing excess carbon dioxide and gradually replacing the depleted oxygen.
Re-breathers incorporate both an oxygen tank and a canister of soda lime which absorbs, or ‘scrubs’ the carbon dioxide from the exhaled air. This canister must be physically repacked with absorbent material before use but the process has been known to fail. Any deficiencies in either the packing process or the quality of the absorbent may result in potentially fatal CO2 poisoning, known as hypercapnia.
The dangers of hypercapnia are well-documented. Consequently strict procedures exist wherever divers or emergency personnel are responsible for checking and repacking soda lime canisters for re-breathers. Nevertheless the physical nature of the task remains vulnerable to poor maintenance or human error.
Safety is greatly enhanced by the integration of a CO2 sensor in the re-breather. This provides an early warning of any increase in CO2 and gives the user valuable time to take action. For re-breathers that are not required to be anti-magnetic, this solution is relatively simple. However, re-breathers that are specified to comply with STANAG 2897 Class A would be compromised by the use of an off-the-shelf CO2 sensor which has a typical (i.e. relatively high) magnetic signature.
Before Analox’s prototype sensor is put into production further tests will be performed to prove its ongoing accuracy and reliability. And whilst details of the technologies involved are commercially sensitive, it is fair to say that the non-magnetic CO2 sensor offers many advantages over those currently available.
An intrinsically safe ndir gas sensor in a can
An NDIR gas sensor is housed within a mechanical housing made up of a
can and a header housing. The header housing body contains a tunnel
waveguide sample chamber or a custom dish sample chamber is formed when
increased sensitivity is required. The header housing also has a top
surface with a pair of windows formed in it and a signal detector, a
reference detector, an infrared source and a signal processor mounted to
it. The can has inner reflective surfaces and the reference detector
and the signal detector are affixed to the top surface so that the inner
reflective surfaces of the can and the sample chamber create a signal
channel path length detected by the signal detector that is greater than
a reference channel path length detected by the reference detector and
an absorption bias between the signal and reference outputs can be used
to determine a gas concentration in the sample chamber. Both the signal
detector and the reference detector have an identical narrow band pass
filter with the same Center Wavelength ("CWL"), Full Width Half Maximum
(FWHM) and transmittance efficiency at the CWL.
Description
An Intrinsically Safe NDIR Gas Sensor in a Can
Field of The Invention
The present application is in the field of gas analysis, and specifically relates to apparatus using a Non-Dispersive Infrared (NDIR) gas analysis technique to determine the concentration of a gas of interest that is present in a chamber by sensing the absorption of infrared radiation passing through the gas.
Background of the Invention
We are living in a gaseous world and the type of gases surrounding our everyday life, for example in where we live, work or play, is vital to our well-being, safety, and even our very survival. Exposure to prolonged insufficient oxygen levels (-15% or less) can make us very sick or might even be fatal to us at times. Too much water vapor in the air surrounding us, especially when the temperature is very high (>90°F), can make us very uncomfortable or seriously ill. For older folks, exposure to high humidity and very high temperature for prolonged periods of time can even be fatal. Unchecked exposure to, or unintentional breathing of, toxic gases above a certain high concentration level such as Carbon Monoxide (70 -400 ppm), Hydrogen Sulfide (50-200 ppm), Formaldehyde (>50 ppb) etc., to name just a few, is extremely hazardous to one's health and often leads to unexpected deaths.
In order to prevent accidental or unintended exposure to unsafe levels of gases, humans have long devised, literally from centuries ago until today, various means of detecting all manners of gases, whether they are actually harmful to them or not. Today one can classify all the significant and still prevalent gas measurement techniques developed to date into two broad categories, namely, interactive and non-interactive types. Among the interactive types are electrochemical fuel cells, tin oxide ( Sn02) sensors, metal oxide semiconductor (MOS) sensors, catalytic (platinum bead) sensors, photo-ionization detectors (PID), flame-ionization detectors (FID), thermal conductivity sensors etc., almost all of which suffer from long-term output drifts, short life span and non-specificity problems. Non-interactive types include Non-Dispersive Infrared (NDIR), photo- acoustic and tunable diode laser absorption spectroscopy (TDLAS) gas sensors. Up and coming non-interactive techniques advanced only during the past two decades include the use of the latest micro electromechanical technologies such as MicroElectronic Mechanical Systems (MEMS) and the so-called Nano- technology. However, probably a few more years have to pass before the potential of these new non-interactive type gas sensors is fully obtainable.
With so many gas detection techniques available over the years, one could easily be misled to believe that gas sensors today must be plentiful and readily available to people to avoid harmful exposure to unhealthy or toxic gases. Unfortunately, at the present time, this is far from being the truth. The reasons are constraints arising from sensor performance and sensor cost. As a result, gas sensors today are deployed for safety reasons only in the most critical and needed circumstances. An example can be cited in the case of the kerosene heater. A kerosene heater is a very cost effective and reliable appliance used all over the world for generating needed heat during the winter months. However, it can also be a deadly appliance when used in a space where there is inadequate ventilation. In such a situation, as oxygen is being consumed without adequate replenishment, the oxygen level in the space can drop to a point.
ISweek（http://www.isweek.com/）- Industry sourcing & Wholesale industrial products
Description
An Intrinsically Safe NDIR Gas Sensor in a Can
Field of The Invention
The present application is in the field of gas analysis, and specifically relates to apparatus using a Non-Dispersive Infrared (NDIR) gas analysis technique to determine the concentration of a gas of interest that is present in a chamber by sensing the absorption of infrared radiation passing through the gas.
Background of the Invention
We are living in a gaseous world and the type of gases surrounding our everyday life, for example in where we live, work or play, is vital to our well-being, safety, and even our very survival. Exposure to prolonged insufficient oxygen levels (-15% or less) can make us very sick or might even be fatal to us at times. Too much water vapor in the air surrounding us, especially when the temperature is very high (>90°F), can make us very uncomfortable or seriously ill. For older folks, exposure to high humidity and very high temperature for prolonged periods of time can even be fatal. Unchecked exposure to, or unintentional breathing of, toxic gases above a certain high concentration level such as Carbon Monoxide (70 -400 ppm), Hydrogen Sulfide (50-200 ppm), Formaldehyde (>50 ppb) etc., to name just a few, is extremely hazardous to one's health and often leads to unexpected deaths.
In order to prevent accidental or unintended exposure to unsafe levels of gases, humans have long devised, literally from centuries ago until today, various means of detecting all manners of gases, whether they are actually harmful to them or not. Today one can classify all the significant and still prevalent gas measurement techniques developed to date into two broad categories, namely, interactive and non-interactive types. Among the interactive types are electrochemical fuel cells, tin oxide ( Sn02) sensors, metal oxide semiconductor (MOS) sensors, catalytic (platinum bead) sensors, photo-ionization detectors (PID), flame-ionization detectors (FID), thermal conductivity sensors etc., almost all of which suffer from long-term output drifts, short life span and non-specificity problems. Non-interactive types include Non-Dispersive Infrared (NDIR), photo- acoustic and tunable diode laser absorption spectroscopy (TDLAS) gas sensors. Up and coming non-interactive techniques advanced only during the past two decades include the use of the latest micro electromechanical technologies such as MicroElectronic Mechanical Systems (MEMS) and the so-called Nano- technology. However, probably a few more years have to pass before the potential of these new non-interactive type gas sensors is fully obtainable.
With so many gas detection techniques available over the years, one could easily be misled to believe that gas sensors today must be plentiful and readily available to people to avoid harmful exposure to unhealthy or toxic gases. Unfortunately, at the present time, this is far from being the truth. The reasons are constraints arising from sensor performance and sensor cost. As a result, gas sensors today are deployed for safety reasons only in the most critical and needed circumstances. An example can be cited in the case of the kerosene heater. A kerosene heater is a very cost effective and reliable appliance used all over the world for generating needed heat during the winter months. However, it can also be a deadly appliance when used in a space where there is inadequate ventilation. In such a situation, as oxygen is being consumed without adequate replenishment, the oxygen level in the space can drop to a point.
ISweek（http://www.isweek.com/）- Industry sourcing & Wholesale industrial products
Mems electrochemical gas sensor
Disclosed is an electrochemical gas sensor using micro electro
mechanical systems (MEMS). The MEMS electrochemical gas sensor includes:
a substrate a lower central region of which is etched by a
predetermined thickness; a first insulation film formed on the
substrate; a heat emitting resistance body formed on the first
insulation film; a second insulation film formed on the heat emitting
resistance body; a reference electrode formed in an upper central region
of the second insulation film; a solid electrolyte formed on the
reference electrode; and a detection electrode formed on the solid
electrolyte.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
This application is based on and claims priority from Korean Patent Application No. 10-2011-0098298, filed on Sep. 28, 2011, with the Korean Intellectual Property Office, the disclosure of which is incorporated herein in its entirety by reference.
TECHNICAL FIELD
The present disclosure relates to an electrochemical gas sensor, and more particularly, to an electrochemical gas sensor using micro electro mechanical systems (MEMS).
BACKGROUND
A representative gas detected by an electrochemical gas sensor includes CO2 CO2 gas is harmless and is an element inevitable for photosynthesis of plants, but an amount of CO2 has increased continually along with the development of the civilization, causing environmental problems such as global warming or abnormal climate due to the green house effect. Accordingly, CO2 gas sensors for regulating carbon credits in the industrial field or exhaust gases of vehicles are being increasingly demanded.
Meanwhile, currently, optical gas sensors using non-dispersive infrared absorption (NDIR) are being mainly used as CO2 gas sensors. While the optical gas sensors can realize an accurate measurement, have a long life span, and show stability, they cannot be easily used as a general sensor due to their high prices and may cause errors in a humid environment.
Studies on potentiometric electrochemical gas sensors are being actively made using solid ionic conductors (solid electrolyte) as sensors capable of overcoming the disadvantage of the optical gas sensors. An electrochemical gas sensor has a simple structure, shows an excellent gas selectivity, and allows a detection of a gas having low concentration of a ppm level. In addition, since electrochemical gas sensors can be manufactured at a low price as compared with the optical gas sensors, there is a high possibility of using the electrochemical gas sensors as a distributed gas analyzer or a general sensor available for homes or offices.
Meanwhile, methods of manufacturing gas electrochemical gas sensors according to the related art include a method of depositing a detection electrode and a reference electrode on one surface of a solid electrolyte ceramic and depositing a high temperature heater for an operation of the sensor on an opposite surface thereof, and a method of stacking a solid electrolyte thick film, a detection electrode, and a reference electrode on one surface of a substrate formed of alumina or quartz and depositing a sensor operating heater on an opposite surface thereof to manufacture an electrochemical gas sensor.
Since the bulk electrochemical gas sensors are resistant to a sudden impact, but require high power consumption and a big size to maintain a high temperature for an operation of the sensor, It is difficult to apply the bulk electrochemical gas sensors to portable terminals or ubiquitous sensor network (USN) sensor nodes.
Accordingly, in order to allow an electrochemical gas sensor to be mounted to a portable terminal, a USN sensor network or the like as a general sensor, a MEMS electrochemical gas sensor needs to consume little power, have a small size, and be mass-produced.
The present disclosure has been made in an effort to provide a MEMS electrochemical gas sensor which has an ultra small size and significantly reduces power consumption.
The present disclosure also has been made in an effort to provide an MEMS electrochemical gas sensor which provides services in various environments.
An exemplary embodiment of the present disclosure provides a MEMS electrochemical gas sensor, including: a substrate a lower central region of which is etched by a predetermined thickness; a first insulation film formed on the substrate; a heat emitting resistance body formed on the first insulation film; a second insulation film formed on the heat emitting resistance body; a reference electrode formed in an upper central region of the second insulation film; a solid electrolyte formed on the reference electrode; and a detection electrode formed on the solid electrolyte.
Another exemplary embodiment of the present disclosure provides a MEMS electrochemical gas sensor, including: a substrate a lower central region of which is etched by a predetermined thickness; a first insulation film formed on the substrate; a heat emitting resistance body formed on the first insulation film; a second insulation film formed on the heat emitting resistance body; a solid electrolyte formed in an upper central region of the second insulation film; a reference electrode formed at one side of an upper portion of the solid electrolyte; and a detection electrode formed at an opposite side of the upper portion of the solid electrolyte.
According to the exemplary embodiments of the present disclosure, power consumption is reduced, as compared with an existing bulk electrochemical gas sensor, by providing an MEMS electrochemical gas sensor where a substrate is etched by a predetermined thickness to thermally isolate insulation films and a heat emitting resistance body.
Further, signal processing/transmitting circuits can be integrated on a substrate by using a semiconductor process and accordingly can be mounted to various systems (for example, a portable terminal, a sensor node or the like) while realizing various services in an extreme environment, by providing a MEMS electrochemical gas sensor having a vertical detection electrode/solid electrolyte/reference electrode structure.
In addition, a MEMS electrochemical gas sensor having low-power characteristics can be used for a long period of time even within a restricted battery capacity, and can be stably driven by using a self-charged power source in various environments where energy converting elements such as a thermoelectric element, a piezoelectric element and the like are operated.
The foregoing summary is illustrative only and is not intended to be in any way limiting. In addition to the illustrative aspects, embodiments, and features described above, further aspects, embodiments, and features will become apparent by reference to the drawings and the following detailed description.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a sectional view illustrating a MEMS electrochemical gas sensor according to an exemplary embodiment of the present disclosure.
FIG. 2 is a view illustrating various shapes of a reference electrode and a detection electrode of the MEMS electrochemical gas sensor according to the exemplary embodiment of the present disclosure.
FIG. 3 is a sectional view illustrating a MEMS electrochemical gas sensor according to another exemplary embodiment of the present disclosure.
FIGS. 4 and 5 are sectional views of MEMS electrochemical gas sensors according to other exemplary embodiments of the present disclosure.
FIGS. 6A to 6G are process flowcharts illustrating a method of manufacturing a MEMS electrochemical gas sensor according to an exemplary embodiment of the present disclosure.
DETAILED DESCRIPTION
In the following detailed description, reference is made to the accompanying drawing, which form a part hereof The illustrative embodiments described in the detailed description, drawing, and claims are not meant to be limiting. Other embodiments may be utilized, and other changes may be made, without departing from the spirit or scope of the subject matter presented here.
Hereinafter, exemplary embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. In a description of the present disclosure, a detailed description of related known configurations and functions will be omitted when it may make the essence of the present disclosure obscure.
FIG. 1 is a sectional view illustrating a MEMS electrochemical gas sensor according to an exemplary embodiment of the present disclosure.
Referring to FIG. 1, the MEMS electrochemical gas sensor according to the exemplary embodiment of the present disclosure includes a substrate 110, a first insulation film 120 formed on the substrate 110, a heat emitting resistance body 130 formed on the first insulation film 120, a second insulation film 140 formed on the heat emitting resistance body 130, a reference electrode 150 formed in an upper central region of the second insulation film 140, a solid electrolyte 160 formed on the reference electrode 150, and a detection electrode 170 formed on the solid electrolyte 160. The MEMS electrochemical gas sensor according to the present disclosure may further include an attachment layer (not shown) using chrome (Cr) or titanium (Ti) between the first insulation film 120 and the heat emitting resistance body 130 to further increase bonding force when the heat emitting resistance body 130 is formed.
ISweek（http://www.isweek.com/）- Industry sourcing & Wholesale industrial products
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
This application is based on and claims priority from Korean Patent Application No. 10-2011-0098298, filed on Sep. 28, 2011, with the Korean Intellectual Property Office, the disclosure of which is incorporated herein in its entirety by reference.
TECHNICAL FIELD
The present disclosure relates to an electrochemical gas sensor, and more particularly, to an electrochemical gas sensor using micro electro mechanical systems (MEMS).
BACKGROUND
A representative gas detected by an electrochemical gas sensor includes CO2 CO2 gas is harmless and is an element inevitable for photosynthesis of plants, but an amount of CO2 has increased continually along with the development of the civilization, causing environmental problems such as global warming or abnormal climate due to the green house effect. Accordingly, CO2 gas sensors for regulating carbon credits in the industrial field or exhaust gases of vehicles are being increasingly demanded.
Meanwhile, currently, optical gas sensors using non-dispersive infrared absorption (NDIR) are being mainly used as CO2 gas sensors. While the optical gas sensors can realize an accurate measurement, have a long life span, and show stability, they cannot be easily used as a general sensor due to their high prices and may cause errors in a humid environment.
Studies on potentiometric electrochemical gas sensors are being actively made using solid ionic conductors (solid electrolyte) as sensors capable of overcoming the disadvantage of the optical gas sensors. An electrochemical gas sensor has a simple structure, shows an excellent gas selectivity, and allows a detection of a gas having low concentration of a ppm level. In addition, since electrochemical gas sensors can be manufactured at a low price as compared with the optical gas sensors, there is a high possibility of using the electrochemical gas sensors as a distributed gas analyzer or a general sensor available for homes or offices.
Meanwhile, methods of manufacturing gas electrochemical gas sensors according to the related art include a method of depositing a detection electrode and a reference electrode on one surface of a solid electrolyte ceramic and depositing a high temperature heater for an operation of the sensor on an opposite surface thereof, and a method of stacking a solid electrolyte thick film, a detection electrode, and a reference electrode on one surface of a substrate formed of alumina or quartz and depositing a sensor operating heater on an opposite surface thereof to manufacture an electrochemical gas sensor.
Since the bulk electrochemical gas sensors are resistant to a sudden impact, but require high power consumption and a big size to maintain a high temperature for an operation of the sensor, It is difficult to apply the bulk electrochemical gas sensors to portable terminals or ubiquitous sensor network (USN) sensor nodes.
Accordingly, in order to allow an electrochemical gas sensor to be mounted to a portable terminal, a USN sensor network or the like as a general sensor, a MEMS electrochemical gas sensor needs to consume little power, have a small size, and be mass-produced.
The present disclosure has been made in an effort to provide a MEMS electrochemical gas sensor which has an ultra small size and significantly reduces power consumption.
The present disclosure also has been made in an effort to provide an MEMS electrochemical gas sensor which provides services in various environments.
An exemplary embodiment of the present disclosure provides a MEMS electrochemical gas sensor, including: a substrate a lower central region of which is etched by a predetermined thickness; a first insulation film formed on the substrate; a heat emitting resistance body formed on the first insulation film; a second insulation film formed on the heat emitting resistance body; a reference electrode formed in an upper central region of the second insulation film; a solid electrolyte formed on the reference electrode; and a detection electrode formed on the solid electrolyte.
Another exemplary embodiment of the present disclosure provides a MEMS electrochemical gas sensor, including: a substrate a lower central region of which is etched by a predetermined thickness; a first insulation film formed on the substrate; a heat emitting resistance body formed on the first insulation film; a second insulation film formed on the heat emitting resistance body; a solid electrolyte formed in an upper central region of the second insulation film; a reference electrode formed at one side of an upper portion of the solid electrolyte; and a detection electrode formed at an opposite side of the upper portion of the solid electrolyte.
According to the exemplary embodiments of the present disclosure, power consumption is reduced, as compared with an existing bulk electrochemical gas sensor, by providing an MEMS electrochemical gas sensor where a substrate is etched by a predetermined thickness to thermally isolate insulation films and a heat emitting resistance body.
Further, signal processing/transmitting circuits can be integrated on a substrate by using a semiconductor process and accordingly can be mounted to various systems (for example, a portable terminal, a sensor node or the like) while realizing various services in an extreme environment, by providing a MEMS electrochemical gas sensor having a vertical detection electrode/solid electrolyte/reference electrode structure.
In addition, a MEMS electrochemical gas sensor having low-power characteristics can be used for a long period of time even within a restricted battery capacity, and can be stably driven by using a self-charged power source in various environments where energy converting elements such as a thermoelectric element, a piezoelectric element and the like are operated.
The foregoing summary is illustrative only and is not intended to be in any way limiting. In addition to the illustrative aspects, embodiments, and features described above, further aspects, embodiments, and features will become apparent by reference to the drawings and the following detailed description.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a sectional view illustrating a MEMS electrochemical gas sensor according to an exemplary embodiment of the present disclosure.
FIG. 2 is a view illustrating various shapes of a reference electrode and a detection electrode of the MEMS electrochemical gas sensor according to the exemplary embodiment of the present disclosure.
FIG. 3 is a sectional view illustrating a MEMS electrochemical gas sensor according to another exemplary embodiment of the present disclosure.
FIGS. 4 and 5 are sectional views of MEMS electrochemical gas sensors according to other exemplary embodiments of the present disclosure.
FIGS. 6A to 6G are process flowcharts illustrating a method of manufacturing a MEMS electrochemical gas sensor according to an exemplary embodiment of the present disclosure.
DETAILED DESCRIPTION
In the following detailed description, reference is made to the accompanying drawing, which form a part hereof The illustrative embodiments described in the detailed description, drawing, and claims are not meant to be limiting. Other embodiments may be utilized, and other changes may be made, without departing from the spirit or scope of the subject matter presented here.
Hereinafter, exemplary embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. In a description of the present disclosure, a detailed description of related known configurations and functions will be omitted when it may make the essence of the present disclosure obscure.
FIG. 1 is a sectional view illustrating a MEMS electrochemical gas sensor according to an exemplary embodiment of the present disclosure.
Referring to FIG. 1, the MEMS electrochemical gas sensor according to the exemplary embodiment of the present disclosure includes a substrate 110, a first insulation film 120 formed on the substrate 110, a heat emitting resistance body 130 formed on the first insulation film 120, a second insulation film 140 formed on the heat emitting resistance body 130, a reference electrode 150 formed in an upper central region of the second insulation film 140, a solid electrolyte 160 formed on the reference electrode 150, and a detection electrode 170 formed on the solid electrolyte 160. The MEMS electrochemical gas sensor according to the present disclosure may further include an attachment layer (not shown) using chrome (Cr) or titanium (Ti) between the first insulation film 120 and the heat emitting resistance body 130 to further increase bonding force when the heat emitting resistance body 130 is formed.
ISweek（http://www.isweek.com/）- Industry sourcing & Wholesale industrial products
Temperature modulation in semiconductor gas sensing
A review of semiconductor gas sensor literature pertaining to the use of
temperature modulation techniques is presented. The temperature
dependence of sensor conductance is discussed, along with transient and
cyclic modulation techniques for improving sensitivity and selectivity
of sensors in the analysis of single gases and multi-component gas
mixtures.
Andrew Lee graduated with a Bachelor of Applied Science (Hons.) from the University of Tasmania in 1997, and is currently studying for his PhD in the School of Applied Science at the same institution. His research project examines the applications of temperature modulation of semiconductor gas sensors to quantitative analysis of gas mixtures.
Brian Reedy received his PhD in inorganic chemistry from the University of Sydney in 1991, and currently lectures in chemistry in the School of Applied Science at the University of Tasmania. His main areas of interest are vibrational spectroscopy, inorganic chemistry and semiconductor gas sensors (temperature modulation and characterisation of sensor surface chemistry).
ISweek（http://www.isweek.com/）- Industry sourcing & Wholesale industrial products
Andrew Lee graduated with a Bachelor of Applied Science (Hons.) from the University of Tasmania in 1997, and is currently studying for his PhD in the School of Applied Science at the same institution. His research project examines the applications of temperature modulation of semiconductor gas sensors to quantitative analysis of gas mixtures.
Brian Reedy received his PhD in inorganic chemistry from the University of Sydney in 1991, and currently lectures in chemistry in the School of Applied Science at the University of Tasmania. His main areas of interest are vibrational spectroscopy, inorganic chemistry and semiconductor gas sensors (temperature modulation and characterisation of sensor surface chemistry).
ISweek（http://www.isweek.com/）- Industry sourcing & Wholesale industrial products
2016年6月27日星期一
Photopatternable Polymeric Membranes for Optical Oxygen Sensors
A new class of optical oxygen sensor that can be photo patternable by
traditional UV lithography is presented. They are fabricated using photo patternable
spin-on silicone (polydimethylsiloxane, PDMS) with oxygen sensitive luminescent
dyes.
It has a good adhesion property and can be applied on glass or on
photopolymer (SU-8) without any additional surface treatments. The optimum
mixture composition for patternable oxygen sensitive membranes is investigated
and its optical properties are characterized.
Proof-of-concepts for two applications, intensity-based oxygen sensing
with SU-8 based structure and self-calibration fluidic oxygen sensor, are
described. These photo patternable optical membranes will find many
applications wherever small patterns of oxygen sensitive membranes are
required.
UV sensor will help prevent skin cancer
Australian researchers have developed a new wearable sensor that tells
you when you have been exposed to too much ultraviolet sunlight.
The simple paper-based UV sensor, to be unveiled at this week's International Nanomedicine Conference in Sydney, changes colour in the sun and could provide an affordable tool to help prevent deadly skin cancers.
Chemists from the Australian Centre for NanoMedicine at the University of NSW, who designed the the low-cost sensor, say it can be worn like stickers on the skin and uses food dyes that change colour after sun exposure.
More importantly the stick-on patches can be tuned to suit individual skin types.
Developer Parisa Sowti Khiabani from UNSW says they wanted to design technology that could help reduce Australia's high incidence of skin cancer.
"Australia has one of the highest incidence of skin cancer in the world, and too much exposure to ultraviolet light is the primary cause," says Mr Khiabani.
According to UNSW Professor Justin Gooding, the technology is ready for the commercial market.
"Its so simple it could be fabricated at home using an inkjet printer and tested in your backyard," he said.
Some of the world's top scientists and clinicians will be in Sydney from Monday to discuss the latest developments in nanomedicine, which is focused on developing technologies with specific medical applications aimed at finding better ways to monitor and treat diseases.
Among the speakers at this year's nanomedicine conference will be former Australian of the Year and plastic surgeon, Professor Fiona Wood who worked with survivors of the Bali bombings.
Prof Wood will discuss ways that nanotechnology can be used to engineer tissue and treat serious burns and other skin injuries.
ISweek（http://www.isweek.com/）- Industry sourcing & Wholesale industrial products
The simple paper-based UV sensor, to be unveiled at this week's International Nanomedicine Conference in Sydney, changes colour in the sun and could provide an affordable tool to help prevent deadly skin cancers.
Chemists from the Australian Centre for NanoMedicine at the University of NSW, who designed the the low-cost sensor, say it can be worn like stickers on the skin and uses food dyes that change colour after sun exposure.
More importantly the stick-on patches can be tuned to suit individual skin types.
Developer Parisa Sowti Khiabani from UNSW says they wanted to design technology that could help reduce Australia's high incidence of skin cancer.
"Australia has one of the highest incidence of skin cancer in the world, and too much exposure to ultraviolet light is the primary cause," says Mr Khiabani.
According to UNSW Professor Justin Gooding, the technology is ready for the commercial market.
"Its so simple it could be fabricated at home using an inkjet printer and tested in your backyard," he said.
Some of the world's top scientists and clinicians will be in Sydney from Monday to discuss the latest developments in nanomedicine, which is focused on developing technologies with specific medical applications aimed at finding better ways to monitor and treat diseases.
Among the speakers at this year's nanomedicine conference will be former Australian of the Year and plastic surgeon, Professor Fiona Wood who worked with survivors of the Bali bombings.
Prof Wood will discuss ways that nanotechnology can be used to engineer tissue and treat serious burns and other skin injuries.
ISweek（http://www.isweek.com/）- Industry sourcing & Wholesale industrial products
Silver Nanoparticle Polymer Composite Based Humidity Sensor
Silver nanoparticles were synthesised by a chemical reduction process in
order to produce an aqueous colloidal dispersion. The resulting
colloids were then characterised by a combination of UV-Vis
spectroscopy, dynamic light scattering, X-ray diffraction and
transmission electron microscopy and the nanoparticles were found to
have an average diameter of 20–22 nm.
The Ag/polymer nanocomposites were then applied to platinum interdigital electrodes as sensor coatings and the capability of the resulting sensor as a humidity detector investigated. With the application of 1 V, a current developed which was found to be directly proportional to humidity levels.
The humidity sensor gives a reversible, selective and rapid response which is proportional to levels of humidity within the range of 10% RH to 60% RH. An investigation into the mechanism of the sensor’s response was conducted and the response was found to correlate well with a second order Langmuir adsorption model.
ISweek（http://www.isweek.com/）- Industry sourcing & Wholesale industrial products
The Ag/polymer nanocomposites were then applied to platinum interdigital electrodes as sensor coatings and the capability of the resulting sensor as a humidity detector investigated. With the application of 1 V, a current developed which was found to be directly proportional to humidity levels.
The humidity sensor gives a reversible, selective and rapid response which is proportional to levels of humidity within the range of 10% RH to 60% RH. An investigation into the mechanism of the sensor’s response was conducted and the response was found to correlate well with a second order Langmuir adsorption model.
ISweek（http://www.isweek.com/）- Industry sourcing & Wholesale industrial products
Gas Sensors Market Size to Exceed $2.512.4 Billion By 2020
“Global gas sensors market” is expected to reach USD 2,512.4 million by
2020, as per a new research report by HexaResearch. High adoption rate
of wireless and smart gas sensor technology coupled with escalating
demand from end-use industries such as automotive is likely to drive
global demand.
Emerging industries such as chemicals, oil & gas, buildings & construction, food & beverages, water treatment and healthcare use gas sensors for safety purpose which is expected to drive the gas sensor market over forecast period. Gas sensors are the most viable equipment to use as a safety device during gas leakage in environment. Gas leakage detection takes place when the gas particles in a particular area increase more than predefined acceptable standards. Portable and non-portable gas sensors both are expected to witness the significant market growth in near future. Some of the major segments where gas sensors are used are automotive industries, process industry, industrial applications, building automation and medical application.
Increased demand from the Asia-Pacific region and government’s safety regulations to increase the demand for gas detection devices are expected to drive the gas sensors market growth. Technical & cost issues are expected to restraint the market growth over the forecast period. Recently emerged green concept building provides the major opportunity for gas sensors market growth in coming years.
Product Insights
Key product segment includes carbon monoxide(CO) sensors, oxygen(O2)sensors, carbon dioxide(CO2) sensors, NOx ammonia(NH3) sensors, methane(CH4) sensors, hydrogen sensors and hydrocarbon sensors. Oxygen sensors are used in automotive space to detect oxygen leakage in vicinity. Sensors monitor oxygen concentration in the vehicle’s exhaust and also they can be installed in engine management systems to control the mix of fuel and air. Hence increasing vehicle production is expected to impact on the growth of the gas sensors market over the forecast period. Methane gas sensors are used to measure gas leakage of compressed natural gas (CNG) in atmosphere. Residential segment is expected to drive the market growth of these gas sensors. MQ-4 and MQ-6 are the examples of methane gas sensors. Carbon dioxide sensors are expected to witness the high growth due to its usage in food storage segment. Food storage segment uses chemical gas sensing and infrared gas sensing technologies to detect increasing spoilage. Carbon monoxide sensors implemented with infrared technology are also expected to witness the significant growth due to its usage in packaging and food storage. NOx sensors are also used in automotive segment to ensure regulatory compulsions. NOx sensors are expected to be the fastest growing sensors segment globally due to the adoption of government regulations for automotive industry.
Technology Insights
Major technologies used in gas sensors are semiconductor, electrochemical, infrared, PID (Photoionization detectors), solid state/metal oxide semiconductor (MOS), catalytic, paramagnetic and thermal conductivity. Electrochemical gas sensors deal with toxic gas concentration detection using oxidation process with the leaked gas. Electrochemical sensors found application in segments such as emission control as indoor air quality and fill gas detection, although such gas sensor is unsuitable for high pressure or low temperature conditions. Basically, electrochemical gas sensors are preferred due to multiple gas detection capability with effectiveness as well as cost efficiency, expected to expel the market growth. Semiconductor sensors measure the change in resistance of a semiconductor material after coming into contact of leaked gas. These sensors are cost efficient, detect combustible and toxic gases. Semiconductor material gas sensors are expected to drive the market growth due to its ideal usage in industries provided with resistance against corrosion and longer life. Infrared gas sensing technology deals with the detection of various gases such as carbon dioxide, methane and volatile organic compounds (VOC) such as butane, benzene and acetylene. However this sensor is costlier than electrochemical gas sensor which is expected to restraint infrared gas sensor market. The life span of these sensors is more in absence of chemical reactions, which is expected to drive the growth of the gas sensor market.
End-Use industry Insights
End use industries of gas sensor market include oil, gas & chemicals, food & beverage, buildings & construction, water treatment, healthcare among others. Other sectors are educational institutes and research & development labs. In healthcare industry, gas sensors are used to measure oxygen gas concentration for anaesthesia gas in ventilators and incubators. In addition to that, they help to detect carbon monoxide in lung operation tests and NOx in inhaled nitric oxide therapy, which is going to impact the market growth positively over forecast period. Furthermore, manufacturing industries uses gas monitoring process to prevent certain adverse situations, increasing the demand for the gas sensors. Government assistance for health and safety of workers is going to further drive the demand for gas sensor technology expelling the market growth in coming years. In automotive segment, gas sensor helps to improve safety applications. Also, hybrid vehicles make use of hydrogen gas sensors, which is anticipated to drive the market growth in coming six years.
Regional Insights
Asia Pacific is expected to have the largest market share in coming years due to increasing automobile market. Increasing demand for handheld devices integrated with gas sensors, has boomed the market growth globally. Furthermore, In Europe, energy efficiency initiatives and emission control standards in automotive segment are expected to drive the gas sensor market in coming years. Growth in end-use segment is expected to spur the gas sensor market growth globally.
ISweek（http://www.isweek.com/）- Industry sourcing & Wholesale industrial products
Emerging industries such as chemicals, oil & gas, buildings & construction, food & beverages, water treatment and healthcare use gas sensors for safety purpose which is expected to drive the gas sensor market over forecast period. Gas sensors are the most viable equipment to use as a safety device during gas leakage in environment. Gas leakage detection takes place when the gas particles in a particular area increase more than predefined acceptable standards. Portable and non-portable gas sensors both are expected to witness the significant market growth in near future. Some of the major segments where gas sensors are used are automotive industries, process industry, industrial applications, building automation and medical application.
Increased demand from the Asia-Pacific region and government’s safety regulations to increase the demand for gas detection devices are expected to drive the gas sensors market growth. Technical & cost issues are expected to restraint the market growth over the forecast period. Recently emerged green concept building provides the major opportunity for gas sensors market growth in coming years.
Product Insights
Key product segment includes carbon monoxide(CO) sensors, oxygen(O2)sensors, carbon dioxide(CO2) sensors, NOx ammonia(NH3) sensors, methane(CH4) sensors, hydrogen sensors and hydrocarbon sensors. Oxygen sensors are used in automotive space to detect oxygen leakage in vicinity. Sensors monitor oxygen concentration in the vehicle’s exhaust and also they can be installed in engine management systems to control the mix of fuel and air. Hence increasing vehicle production is expected to impact on the growth of the gas sensors market over the forecast period. Methane gas sensors are used to measure gas leakage of compressed natural gas (CNG) in atmosphere. Residential segment is expected to drive the market growth of these gas sensors. MQ-4 and MQ-6 are the examples of methane gas sensors. Carbon dioxide sensors are expected to witness the high growth due to its usage in food storage segment. Food storage segment uses chemical gas sensing and infrared gas sensing technologies to detect increasing spoilage. Carbon monoxide sensors implemented with infrared technology are also expected to witness the significant growth due to its usage in packaging and food storage. NOx sensors are also used in automotive segment to ensure regulatory compulsions. NOx sensors are expected to be the fastest growing sensors segment globally due to the adoption of government regulations for automotive industry.
Technology Insights
Major technologies used in gas sensors are semiconductor, electrochemical, infrared, PID (Photoionization detectors), solid state/metal oxide semiconductor (MOS), catalytic, paramagnetic and thermal conductivity. Electrochemical gas sensors deal with toxic gas concentration detection using oxidation process with the leaked gas. Electrochemical sensors found application in segments such as emission control as indoor air quality and fill gas detection, although such gas sensor is unsuitable for high pressure or low temperature conditions. Basically, electrochemical gas sensors are preferred due to multiple gas detection capability with effectiveness as well as cost efficiency, expected to expel the market growth. Semiconductor sensors measure the change in resistance of a semiconductor material after coming into contact of leaked gas. These sensors are cost efficient, detect combustible and toxic gases. Semiconductor material gas sensors are expected to drive the market growth due to its ideal usage in industries provided with resistance against corrosion and longer life. Infrared gas sensing technology deals with the detection of various gases such as carbon dioxide, methane and volatile organic compounds (VOC) such as butane, benzene and acetylene. However this sensor is costlier than electrochemical gas sensor which is expected to restraint infrared gas sensor market. The life span of these sensors is more in absence of chemical reactions, which is expected to drive the growth of the gas sensor market.
End-Use industry Insights
End use industries of gas sensor market include oil, gas & chemicals, food & beverage, buildings & construction, water treatment, healthcare among others. Other sectors are educational institutes and research & development labs. In healthcare industry, gas sensors are used to measure oxygen gas concentration for anaesthesia gas in ventilators and incubators. In addition to that, they help to detect carbon monoxide in lung operation tests and NOx in inhaled nitric oxide therapy, which is going to impact the market growth positively over forecast period. Furthermore, manufacturing industries uses gas monitoring process to prevent certain adverse situations, increasing the demand for the gas sensors. Government assistance for health and safety of workers is going to further drive the demand for gas sensor technology expelling the market growth in coming years. In automotive segment, gas sensor helps to improve safety applications. Also, hybrid vehicles make use of hydrogen gas sensors, which is anticipated to drive the market growth in coming six years.
Regional Insights
Asia Pacific is expected to have the largest market share in coming years due to increasing automobile market. Increasing demand for handheld devices integrated with gas sensors, has boomed the market growth globally. Furthermore, In Europe, energy efficiency initiatives and emission control standards in automotive segment are expected to drive the gas sensor market in coming years. Growth in end-use segment is expected to spur the gas sensor market growth globally.
ISweek（http://www.isweek.com/）- Industry sourcing & Wholesale industrial products
2016年6月25日星期六
Graphene photosensor integrated into computer chip
Today, most information is transmitted by light – for
example in optical fibres. Computer chips, however, work electronically.
Somewhere between the optical data highway and the electronic chips, photons have
to be converted into electrons using light-detectors.
Scientists at the Vienna University
of Technology have integrated a graphene photosensor with a
standard silicon chip. The hybrid device can transform light of all important
telecommunications frequencies into electrical signals. The scientific results
have now been published in the journal Nature Photonics.
Optical fiber transmission uses wavelengths that are in the near-infrared
portion of the spectrum. Typical wavelengths are 850nm, 1310nm, and 1550nm.
Both lasers and LEDs are used as transmission sources; lasers usually for 1310
or 1550nm single-mode applications while LEDs typically for 850nm or 1300nm
multimode applications.
Both academia and the industry are placing high hopes in graphene for many
different applications. Two years ago, the team of Thomas Müller (Institute of Photonics
Müller commented, “There are many materials that can transform light into
electrical signals, but graphene allows for a particularly fast conversion. So
wherever large amounts of data are to be transmitted in a short period of time,
graphene will in the future probably be the material of choice.”
Significant development
The researchers had to come a long way from the basic proof of what the
material can do to actually using it in a chip – but now they have succeeded.
The Viennese team worked together with researchers from the Johannes Kepler University in Linz
Müller added, “A narrow waveguide with a diameter of about 200 by 500
nanometers carries the optical signal to the graphene layer. There, the light
is converted into an electrical signal, which can then be processed in the
chip. There have already been attempts to integrate photodetectors made of
other materials, such as germanium, directly into a chip. However, these
materials can only process light of a specific wavelength range.”
The researchers say that they can show that graphene can convert all
wavelengths which are used in telecommunications equally well. The graphene
photodetector is not only extremely fast, it can also be built in a
particularly compact way: for example, 20 000 such detectors could fit onto a
single chip with a surface area of 1cm2. Theoretically, the chip could
be supplied with data via 20,000 different information channels.
”These technologies are not only important for transmitting data over
large distances. Optical data transmission also becomes more and more important
for communication within computers”, says Thomas Müller. When large computer
clusters work with many processor cores at the same time, a lot of information
has to be transferred between the cores. As graphene allows switching between
optical and electrical signals very quickly, this data can be exchanged
optically. This speeds up the data exchange and requires much less electrical
energy.
W The light signal arrives
throuth a waveguide (left), in the 2 micrometer wide graphene sheet, electrical
current is generated. G
Graphene - a two
dimensional sheet made of carbon atoms - can convert light into electrical
current. "CMOS-compatible graphene photodetector covering all optical
communication bands", Pospischil et al., Nature Photonics (2013),
doi:10.1038/nphoton.2013.240
Indicators for optical oxygen sensors
Continuous monitoring of oxygen concentration is of great
importance in many different areas of research which range from medical
applications to food packaging. In the last three decades, significant progress
has been made in the field of optical sensing technology and this review will
highlight the one inherent to the development of oxygen indicators. The first
section outlines the bioanalytical fields in which optical oxygen sensors have
been applied. The second section gives the reader a comprehensive summary of
the existing oxygen indicators with a critical highlight on their photophysical
and sensing properties. Altogether, this review is meant to give the potential
user a guide to select the most suitable oxygen indicator for the particular
application of interest.
Oxygen
is by far one of the most important chemical species on earth since it is
essential for life. Measurements of its concentration are of extreme importance
in many different research fields such as: medicine, chemistry, environmental
and marine analysis, molecular biotechnology, bioprocess control, food
packaging, and industrial production monitoring. In the majority of the cases,
it would be ideal to monitor oxygen concentration continuously which implies
the use of oxygen sensors: a class of chemical sensors and by definition “a miniaturized device that can deliver real-time and
on-line information on the presence of specific compounds or ions in even
complex samples” .
Several methods
for oxygen detection exist and can be classified on the basis of the principle
used in electrochemical (amperometric, potentiometric, or conductometric),
optical (absorption changes or photoluminescence), and chemical (Winkler
titration).Since its development, the
Optical chemical sensors can be divided in several subgroups depending on the working principle applied; practically all spectroscopic methods have been used (absorption spectroscopy, reflectometry, luminescence, infrared and Raman spectroscopies, interferometry, and surface plasmon resonance). The majority of the optical sensors developed for oxygen detection rely on quenching of the luminescence of an indicator dye by molecular oxygen.
Typical layouts consist of a luminescent dye, whose optical properties are reversibly influenced by the presence of molecular oxygen, which is usually incorporated into a polymeric matrix and deposited on a solid support (planar waveguide, microtitre plate, or optical fiber). Nano- and microparticle-based oxygen probes have also proved to be important analytical tools.
The field of application plays an important role in the choice of the indicator dye and, as a consequence, of the matrix material and detection method. For example, when measuring oxygen in live cells or in tissues, it is necessary to take into account the autofluorescence generated by the presence of biological substances such as proteins, DNA, and melanin. In such cases, in order to minimize absorption and scattering of the excitation and emission light in the tissue, it is preferable to employ indicators that show longwave-shifted absorption (590–650 nm) and emission (730–900 nm) bands. On the other hand, when measuring ultrafast oxygen dynamics, for example in breath monitoring application , it is crucial to use optodes with a very fast response time which can be achieved by employing very thin sensing layers and indicator dyes possessing exceptional brightness.
The
scope of this review is not only to provide the reader with a selection of
recently developed oxygen indicators but also to give a feeling about the area
of applicability with a special focus on bioanalysis.
Samsung's Galaxy Note 4 might have an ultraviolet sensor(UV sensor), and it might actually be useful
It
has already been confirmed by Samsung that the Galaxy Note 4
will have an ultraviolet (UV) sensor, but there wasn't much information
available. Now, according to a report over on SamMobile, we have some idea as to what
consumers can expect to see from the built-in
functionality. The new component will integrate itself within Samsung's S Health app, providing
yet more personal data for the owner to take advantage of.
Is it gimmicky? Sure. It's Samsung, the home of the smartphone heart-rate monitor, but it is cool at the same time.
So how exactly does the UV sensor work? It measures the sun's ultraviolet radiation and prevents owners from potentially damaging their skin, increasing the risk of skin cancer. This is possible thanks to recommended guidance provided, based on the current UV index level measured at that point in time. All that's required to measure the radiation is to maintain a 60 degree angle of elevation towards the sun against the back of the sensor.
We noted that it's a useful and rather cool feature simply because people are generally fairly ignorant when it comes to keeping safe in the sun. To help keep everyone safe from being exposed to too much UV rays, Samsung will provide a full explanation on each level of UV index level, as well as some cool truths and false statements in the app.
Is it gimmicky? Sure. It's Samsung, the home of the smartphone heart-rate monitor, but it is cool at the same time.
So how exactly does the UV sensor work? It measures the sun's ultraviolet radiation and prevents owners from potentially damaging their skin, increasing the risk of skin cancer. This is possible thanks to recommended guidance provided, based on the current UV index level measured at that point in time. All that's required to measure the radiation is to maintain a 60 degree angle of elevation towards the sun against the back of the sensor.
We noted that it's a useful and rather cool feature simply because people are generally fairly ignorant when it comes to keeping safe in the sun. To help keep everyone safe from being exposed to too much UV rays, Samsung will provide a full explanation on each level of UV index level, as well as some cool truths and false statements in the app.
Here's the information that will allegedly be included in the app, as
outlined by SamMobile:
The truths:
·
A tan results from your
body defending itself against further damage from UV radiation.
·
A dark tan on white skin
offers only limited protection equivalent to an SPF of about 4.
·
Up to 80% of solar UV
radiation can penetrate light cloud cover. Haze in the atmosphere can even
increase UV radiation exposure.
·
Water offers only minimal
protection from UV radiation, and reflection from water can enhance your UV
radiation exposure.
·
UV radiation is generally
lower during the winter months, but snow reflection can double your overall
exposure, especially at high altitude. Pay particular attention in early spring
when temperatures are low but sun's rays are unexpectedly strong.
·
Sunscreens should not be
used to increase sun exposure time but to increase protection during
unavoidable exposure. The protection they afford depends critically on their
correct application.
·
UV radiation exposure is
cumulative during the day.
·
Sunburn is caused by UV
radiation which cannot be felt. The heating effect is caused by the sun's
infrared radiation and not by UV radiation
The statements below are false:
·
A suntan is healthy.
·
A tan protects you from the
sun.
·
You can't get sunburnt on a
cloudy day.
·
You can't get sunburnt
while in the water.
·
UV radiation during the
winter is not dangerous.
·
Sunscreens protect me so I
can sunbathe much longer.
·
If you take regular breaks
during sunbathing you won't get sunburnt.
·
If you don't fell the hot
rays of the sun you won't get sunburnt.
Install a Humidity Sensor to Automatically Control Your Exhaust Fan
Exhaust fans help prevent mold and mildew in bathrooms and basements, but when left on, they waste electricity. Automate this process by installing a humidity sensor to replace the fan switch.
A humidity sensor includes a manual fan switch, but if your sensor is setup correctly it should turn on and off based on the humidity in the room. With most sensors you can also tell it how long it should run when it senses a certain level of humidity.
Installing a humidity sensor is a DIY project, but you must first determine if your switch box has a neutral wire, which is required to install a device like this. Watch the video above to check out the full instructions. The Leviton humidity sensor shown runs $31.49 from Amazon.
2016年6月24日星期五
Gas sensor technologies for fire detection
The physical mechanisms of spreading of smoke and gas during
a fire event must not be necessarily the same. Due to the heat smoke particles
are more likely transported by convection with a minor contribution of diffusion
effects whereas gas is transported by both convection and presumably with a
higher fraction of diffusion.
In order to investigate these differences we selected a
variety of gas sensors and placed them at different positions in a fire test
room. Gas sensitive field effect transistor (GasFET)-arrays, metal oxide
sensors (MOS) and electrochemical cells (ECs) were used for gas measurements in
test fire scenarios. Beside the investigation of the performance of the sensor
elements itself, we additionally focused our investigations on the propagation
behavior of different aerosol and gas components of standardized (EN54) test
fires in time and space.
We mounted different gas sensors on PCBs which were setup
into different vertical “multi-sensor” chains representing a measurement grid
in space. The metal oxide sensors showed the fastest response whereas the
GasFET-array was responding slower but shows advantages with respect to
low-power consumption and pattern recognition capabilities. The EC carbon monoxide
sensor has a good selectivity but a high price comparing to semiconductors. We
observed that smoke aerosols mainly stay beneath the ceiling whereas the fire
related gases also are transported in regions below the ceiling and near to the
floor.
As a very surprising and promising result we observed that
gases also diffuse through heat layers which may occur during fires right below
the ceiling and which smoke particles are not able to pass through and thus are
not able to enter into the detector to reach the optical measurement chamber.
In our case CO reached the gas sensors over 4 min earlier before any smoke
could be detected by optical smoke detectors.
What Is a CO2 Sensor?
Carbon dioxide is a deadly gas that can kill a person before they realize what is happening. Because it is odorless and colorless, you may not even know it is present without a detector. Exposure to carbon dioxide can cause headaches, nausea, vomiting and even death. A Co2 sensor (or carbon dioxide sensor) detects the presence of carbon dioxide in an area. This device indicates the quality of indoor air, and it is ideal for industrial and commercial applications.
How Co2 Sensors Operate
Carbon dioxide sensors have a wide range of applications. They are ideal for the HVAC industry to measure the quality of indoor air, as well as ventilation on air conditioning systems. They monitor the level of carbon dioxide in a building to tell the HVAC system when fresh air is needed to restore optimal airflow. They measure air quality in terrestrial and space applications, measure Co2 levels in greenhouses, and are useful in many other industries.
NDIR Co2 Sensors
Two basic types of Co2 sensors exist. The first is the non-dispersive infrared (or NDIR) Co2 sensor. A NDIR sensor is a spectroscopic sensor that uses a light tube, an infrared source, infrared detector and a wavelength filter. The highest quality of these devices measures gas with sensitivities between 20 and 50 PPM. Waves of light go through the tube towards an infrared light detector while the gas absorbs the light. All remaining light is absorbed, except that absorbed by the carbon dioxide. The detector reads the amount not absorbed by either the CO2 or the filter. The measured difference tells how many carbon dioxide molecules are in the air.
Chemical Co2 Sensors
The second type of carbon dioxide sensor is a chemical Co2 sensor. It uses as many as three electrodes and an electrolyte. The carbon dioxide passes through the chemical sensor to produce a measurable electrochemical reaction. One of the popular options in this category is the nanotechnology based chemical sensor. It is portable, and provides high sensitivity and low cost and power needs. Chemical Co2 sensors are valuable in space applications.
Calibrating a Co2 Sensor
Carbon dioxide sensors that measure air quality may need calibration to ensure accurate results. This requires using either outdoor air or a calibration gas. When calibrating with outside air, users must place the device away from objects that release carbon dioxide, such as running vehicles and heavy vegetation. Once the device has been calibrated, it is ready to use.
Top Brands of Co2 Sensors
Several manufacturers make CO2 sensors for various applications. Honeywell is renowned for HVAC sensors that ensure the correct quality of air for air conditioners and ventilation systems. They sell wall-mounted sensors that connect to the HVAC system. These infrared systems measure the air in a duct or an open area.
GE manufactures Co2 sensors for use in residential and industrial applications. They work with HVAC systems, and measure refrigerant in automobiles and commercial refrigeration systems. This company provides a range of products with many of them being self-calibrated. They are often wall-mounted with easy wiring installation. Buyers have the option to choose a water-resistant product for use in specific projects.
Extech makes desktop air quality sensors with NDIR technology. Some items come with warning alerts to let users know when the quality of air is insufficient and carbon dioxide levels are too high. Some of these products calibrate themselves and require almost no maintenance to ensure accurate results.
订阅：
博文 (Atom)