1700 deg C optical temperature sensor

NASA Technical Reports Server (NTRS)

Mossey, P. W.; Shaffernocker, W. M.; Mulukutla, A. R.

1986-01-01

A new gas temperature sensor was developed that shows promise of sufficient ruggedness to be useful as a gas turbine temperature sensor. The sensor is in the form of a single-crystal aluminum oxide ceramic, ground to a cone shape and given an emissive coating. A lens and an optical fiber conduct the thermally emitted light to a remote and near-infrared photodetector assembly. Being optically coupled and passive, the sensor is highly immune to all types of electrical interference. Candidate sensors were analyzed for optical sensor performance, heat transfer characteristics, stress from gas loading. This led to the selection of the conical shape as the most promising for the gas turbine environment. One uncoated and two coated sensing elements were prepared for testing. Testing was conducted to an indicated 1750 C in a propane-air flame. Comparison with the referee optical pyrometer shows an accuracy of + or - 25 C at 1700 C for this initial development. One hundred cycles from room temperature to 1700 C left the sapphire cone intact, but some loss of the platinum, 6% rhodium coating was observed. Several areas for improving the overall performance and durability are identified.

Impact Analysis of Temperature and Humidity Conditions on Electrochemical Sensor Response in Ambient Air Quality Monitoring

PubMed Central

Ning, Zhi; Ye, Sheng; Sun, Li; Yang, Fenhuan; Wong, Ka Chun; Westerdahl, Dane; Louie, Peter K. K.

2018-01-01

The increasing applications of low-cost air sensors promises more convenient and cost-effective systems for air monitoring in many places and under many conditions. However, the data quality from such systems has not been fully characterized and may not meet user expectations in research and regulatory uses, or for use in citizen science. In our study, electrochemical sensors (Alphasense B4 series) for carbon monoxide (CO), nitric oxide (NO), nitrogen dioxide (NO2), and oxidants (Ox) were evaluated under controlled laboratory conditions to identify the influencing factors and quantify their relation with sensor outputs. Based on the laboratory tests, we developed different correction methods to compensate for the impact of ambient conditions. Further, the sensors were assembled into a monitoring system and tested in ambient conditions in Hong Kong side-by-side with regulatory reference monitors, and data from these tests were used to evaluate the performance of the models, to refine them, and validate their applicability in variable ambient conditions in the field. The more comprehensive correction models demonstrated enhanced performance when compared with uncorrected data. One over-arching observation of this study is that the low-cost sensors may promise excellent sensitivity and performance, but it is essential for users to understand and account for several key factors that may strongly affect the nature of sensor data. In this paper, we also evaluated factors of multi-month stability, temperature, and humidity, and considered the interaction of oxidant gases NO2 and ozone on a newly introduced oxidant sensor. PMID:29360749

Impact Analysis of Temperature and Humidity Conditions on Electrochemical Sensor Response in Ambient Air Quality Monitoring.

PubMed

Wei, Peng; Ning, Zhi; Ye, Sheng; Sun, Li; Yang, Fenhuan; Wong, Ka Chun; Westerdahl, Dane; Louie, Peter K K

2018-01-23

The increasing applications of low-cost air sensors promises more convenient and cost-effective systems for air monitoring in many places and under many conditions. However, the data quality from such systems has not been fully characterized and may not meet user expectations in research and regulatory uses, or for use in citizen science. In our study, electrochemical sensors (Alphasense B4 series) for carbon monoxide (CO), nitric oxide (NO), nitrogen dioxide (NO₂), and oxidants (O x ) were evaluated under controlled laboratory conditions to identify the influencing factors and quantify their relation with sensor outputs. Based on the laboratory tests, we developed different correction methods to compensate for the impact of ambient conditions. Further, the sensors were assembled into a monitoring system and tested in ambient conditions in Hong Kong side-by-side with regulatory reference monitors, and data from these tests were used to evaluate the performance of the models, to refine them, and validate their applicability in variable ambient conditions in the field. The more comprehensive correction models demonstrated enhanced performance when compared with uncorrected data. One over-arching observation of this study is that the low-cost sensors may promise excellent sensitivity and performance, but it is essential for users to understand and account for several key factors that may strongly affect the nature of sensor data. In this paper, we also evaluated factors of multi-month stability, temperature, and humidity, and considered the interaction of oxidant gases NO₂ and ozone on a newly introduced oxidant sensor.

Empowering smartphone users with sensor node for air quality measurement

NASA Astrophysics Data System (ADS)

Oletic, Dinko; Bilas, Vedran

2013-06-01

We present an architecture of a sensor node developed for use with smartphones for participatory sensing of air quality in urban environments. Our solution features inexpensive metal-oxide semiconductor gas sensors (MOX) for measurement of CO, O3, NO2 and VOC, along with sensors for ambient temperature and humidity. We focus on our design of sensor interface consisting of power-regulated heater temperature control, and the design of resistance sensing circuit. Accuracy of the sensor interface is characterized. Power consumption of the sensor node is analysed. Preliminary data obtained from the CO gas sensors in laboratory conditions and during the outdoor field-test is shown.

Temperature insensitive curvature sensor based on cascading photonic crystal fiber

NASA Astrophysics Data System (ADS)

Fu, Guangwei; Li, Yunpu; Fu, Xinghu; Jin, Wa; Bi, Weihong

2018-03-01

A temperature insensitive curvature sensor is proposed based on cascading photonic crystal fiber. Using the arc fusion splicing method, this sensor is fabricated by cascading together a single-mode fiber (SMF), a three layers air holes structure of photonic crystal fiber (3PCF), a five layers air holes structure of photonic crystal fiber (5PCF) and a SMF in turn. So the structure SMF-3PCF-5PCF-SMF can be obtained with a total length of 20 mm. During the process of fabrication, the splicing machine parameters and the length of each optical fiber are adjusted to obtain a high sensitivity curvature sensor. The experimental results show that the curvature sensitivity is -8.40 nm/m-1 in the curvature variation range of 0-1.09 m-1, which also show good linearity. In the range of 30-90 °C, the temperature sensitivity is only about 3.24 pm/°C, indicating that the sensor is not sensitive to temperature. The sensor not only has the advantages of easy fabricating, simple structure, high sensitivity but also can solve the problem of temperature measurement cross sensitivity, so it can be used for different areas including aerospace, large-scale bridge, architectural structure health monitoring and so on.

Development and evaluation of optical fiber NH3 sensors for application in air quality monitoring

NASA Astrophysics Data System (ADS)

Huang, Yu; Wieck, Lucas; Tao, Shiquan

2013-02-01

Ammonia is a major air pollutant emitted from agricultural practices. Sources of ammonia include manure from animal feeding operations and fertilizer from cropping systems. Sensor technologies with capability of continuous real time monitoring of ammonia concentration in air are needed to qualify ammonia emissions from agricultural activities and further evaluate human and animal health effects, study ammonia environmental chemistry, and provide baseline data for air quality standard. We have developed fiber optic ammonia sensors using different sensing reagents and different polymers for immobilizing sensing reagents. The reversible fiber optic sensors have detection limits down to low ppbv levels. The response time of these sensors ranges from seconds to tens minutes depending on transducer design. In this paper, we report our results in the development and evaluation of fiber optic sensor technologies for air quality monitoring. The effect of change of temperature, humidity and carbon dioxide concentration on fiber optic ammonia sensors has been investigated. Carbon dioxide in air was found not interfere the fiber optic sensors for monitoring NH3. However, the change of humidity can cause interferences to some fiber optic NH3 sensors depending on the sensor's transducer design. The sensitivity of fiber optic NH3 sensors was found depends on temperature. Methods and techniques for eliminating these interferences have been proposed.

Linear air-fuel sensor development

DOE Office of Scientific and Technical Information (OSTI.GOV)

Garzon, F.; Miller, C.

1996-12-14

The electrochemical zirconia solid electrolyte oxygen sensor, is extensively used for monitoring oxygen concentrations in various fields. They are currently utilized in automobiles to monitor the exhaust gas composition and control the air-to-fuel ratio, thus reducing harmful emission components and improving fuel economy. Zirconia oxygen sensors, are divided into two classes of devices: (1) potentiometric or logarithmic air/fuel sensors; and (2) amperometric or linear air/fuel sensors. The potentiometric sensors are ideally suited to monitor the air-to-fuel ratio close to the complete combustion stoichiometry; a value of about 14.8 to 1 parts by volume. This occurs because the oxygen concentration changesmore » by many orders of magnitude as the air/fuel ratio is varied through the stoichiometric value. However, the potentiometric sensor is not very sensitive to changes in oxygen partial pressure away from the stoichiometric point due to the logarithmic dependence of the output voltage signal on the oxygen partial pressure. It is often advantageous to operate gasoline power piston engines with excess combustion air; this improves fuel economy and reduces hydrocarbon emissions. To maintain stable combustion away from stoichiometry, and enable engines to operate in the excess oxygen (lean burn) region several limiting-current amperometric sensors have been reported. These sensors are based on the electrochemical oxygen ion pumping of a zirconia electrolyte. They typically show reproducible limiting current plateaus with an applied voltage caused by the gas diffusion overpotential at the cathode.« less

Temperature and Humidity Calibration of a Low-Cost Wireless Dust Sensor for Real-Time Monitoring.

PubMed

Hojaiji, Hannaneh; Kalantarian, Haik; Bui, Alex A T; King, Christine E; Sarrafzadeh, Majid

2017-03-01

This paper introduces the design, calibration, and validation of a low-cost portable sensor for the real-time measurement of dust particles within the environment. The proposed design consists of low hardware cost and calibration based on temperature and humidity sensing to achieve accurate processing of airborne dust density. Using commercial particulate matter sensors, a highly accurate air quality monitoring sensor was designed and calibrated using real world variations in humidity and temperature for indoor and outdoor applications. Furthermore, to provide a low-cost secure solution for real-time data transfer and monitoring, an onboard Bluetooth module with AES data encryption protocol was implemented. The wireless sensor was tested against a Dylos DC1100 Pro Air Quality Monitor, as well as an Alphasense OPC-N2 optical air quality monitoring sensor for accuracy. The sensor was also tested for reliability by comparing the sensor to an exact copy of itself under indoor and outdoor conditions. It was found that accurate measurements under real-world humid and temperature varying and dynamically changing conditions were achievable using the proposed sensor when compared to the commercially available sensors. In addition to accurate and reliable sensing, this sensor was designed to be wearable and perform real-time data collection and transmission, making it easy to collect and analyze data for air quality monitoring and real-time feedback in remote health monitoring applications. Thus, the proposed device achieves high quality measurements at lower-cost solutions than commercially available wireless sensors for air quality.

Fiber optic distributed temperature sensor mapping of a jet-mixing flow field

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lomperski, Stephen; Gerardi, Craig; Pointer, William David

In this paper, we introduce the use of a Rayleigh backscatter-based distributed fiber optic sensor to map the temperature field in air flow for a thermal fatigue application. The experiment involves a pair of air jets at 22 and 70°C discharging from 136 mm hexagonal channels into a 1 × 1 × 1.7 m tank at atmospheric pressure. A 40 m-long, Φ155 µm fiber optic sensor was wound back and forth across the tank midplane to form 16 horizontal measurement sections with a vertical spacing of 51 mm. This configuration generated a 2D temperature map with 2800 data points overmore » a 0.76 × 1.7 m plane. Fiber optic sensor readings were combined with PIV and infrared measurements to relate flow field characteristics to the thermal signature of the tank lid. The paper includes sensor stability data and notes issues encountered using the distributed temperature sensor in a flow field. In conclusion, sensors are sensitive to strain and humidity, and so accuracy relies upon strict control of both.« less

Fiber optic distributed temperature sensor mapping of a jet-mixing flow field

DOE PAGES

Lomperski, Stephen; Gerardi, Craig; Pointer, William David

2015-03-04

In this paper, we introduce the use of a Rayleigh backscatter-based distributed fiber optic sensor to map the temperature field in air flow for a thermal fatigue application. The experiment involves a pair of air jets at 22 and 70°C discharging from 136 mm hexagonal channels into a 1 × 1 × 1.7 m tank at atmospheric pressure. A 40 m-long, Φ155 µm fiber optic sensor was wound back and forth across the tank midplane to form 16 horizontal measurement sections with a vertical spacing of 51 mm. This configuration generated a 2D temperature map with 2800 data points overmore » a 0.76 × 1.7 m plane. Fiber optic sensor readings were combined with PIV and infrared measurements to relate flow field characteristics to the thermal signature of the tank lid. The paper includes sensor stability data and notes issues encountered using the distributed temperature sensor in a flow field. In conclusion, sensors are sensitive to strain and humidity, and so accuracy relies upon strict control of both.« less

High temperature sensor

DOEpatents

Tokarz, Richard D.

1982-01-01

A high temperature sensor includes a pair of electrical conductors separated by a mass of electrical insulating material. The insulating material has a measurable resistivity within the sensor that changes in relation to the temperature of the insulating material within a high temperature range (1,000 to 2,000 K.). When required, the sensor can be encased within a ceramic protective coating.

Fiber ring laser sensor based on Fabry-Perot cavity interferometer for temperature sensing

NASA Astrophysics Data System (ADS)

Zou, Hui; Ma, Lei; Xiong, Hui; Zhang, Yunshan; Li, Yong Tao

2018-01-01

A ring laser temperature sensor based on a novel reflective fiber Fabry-Perot (F-P) interferometer air cavity is proposed and experimentally demonstrated. The reflective F-P air cavity, which consists of a segment of glass capillary inserted between two single-mode fibers, is utilized as a sensing element as well as as a filter in the fiber ring cavity. As temperature increases, the reflection spectra of the F-P sensor move towards the longer wavelength, and then cause lasing wavelength shifts. By monitoring the variation of lasing wavelength, we obtain a temperature sensor system with a high temperature sensitivity of 0.249 nm °C-1, a narrow 3 dB bandwidth of 0.1514 nm, and a high signal-to-noise ratio of 52 dB. Moreover, it is convenient to fabricate the sensor head, and the stability is very good, giving it a wide range of applications.

Empirical downscaling of daily minimum air temperature at very fine resolutions in complex terrain

Treesearch

Zachary A. Holden; John T. Abatzoglou; Charles H. Luce; L. Scott Baggett

2011-01-01

Available air temperature models do not adequately account for the influence of terrain on nocturnal air temperatures. An empirical model for night time air temperatures was developed using a network of one hundred and forty inexpensive temperature sensors deployed across the Bitterroot National Forest, Montana. A principle component analysis (PCA) on minimum...

Ultraflexible, large-area, physiological temperature sensors for multipoint measurements

PubMed Central

Yokota, Tomoyuki; Inoue, Yusuke; Terakawa, Yuki; Reeder, Jonathan; Kaltenbrunner, Martin; Ware, Taylor; Yang, Kejia; Mabuchi, Kunihiko; Murakawa, Tomohiro; Sekino, Masaki; Voit, Walter; Sekitani, Tsuyoshi; Someya, Takao

2015-01-01

We report a fabrication method for flexible and printable thermal sensors based on composites of semicrystalline acrylate polymers and graphite with a high sensitivity of 20 mK and a high-speed response time of less than 100 ms. These devices exhibit large resistance changes near body temperature under physiological conditions with high repeatability (1,800 times). Device performance is largely unaffected by bending to radii below 700 µm, which allows for conformal application to the surface of living tissue. The sensing temperature can be tuned between 25 °C and 50 °C, which covers all relevant physiological temperatures. Furthermore, we demonstrate flexible active-matrix thermal sensors which can resolve spatial temperature gradients over a large area. With this flexible ultrasensitive temperature sensor we succeeded in the in vivo measurement of cyclic temperatures changes of 0.1 °C in a rat lung during breathing, without interference from constant tissue motion. This result conclusively shows that the lung of a warm-blooded animal maintains surprising temperature stability despite the large difference between core temperature and inhaled air temperature. PMID:26554008

Ultraflexible, large-area, physiological temperature sensors for multipoint measurements.

PubMed

Yokota, Tomoyuki; Inoue, Yusuke; Terakawa, Yuki; Reeder, Jonathan; Kaltenbrunner, Martin; Ware, Taylor; Yang, Kejia; Mabuchi, Kunihiko; Murakawa, Tomohiro; Sekino, Masaki; Voit, Walter; Sekitani, Tsuyoshi; Someya, Takao

2015-11-24

We report a fabrication method for flexible and printable thermal sensors based on composites of semicrystalline acrylate polymers and graphite with a high sensitivity of 20 mK and a high-speed response time of less than 100 ms. These devices exhibit large resistance changes near body temperature under physiological conditions with high repeatability (1,800 times). Device performance is largely unaffected by bending to radii below 700 µm, which allows for conformal application to the surface of living tissue. The sensing temperature can be tuned between 25 °C and 50 °C, which covers all relevant physiological temperatures. Furthermore, we demonstrate flexible active-matrix thermal sensors which can resolve spatial temperature gradients over a large area. With this flexible ultrasensitive temperature sensor we succeeded in the in vivo measurement of cyclic temperatures changes of 0.1 °C in a rat lung during breathing, without interference from constant tissue motion. This result conclusively shows that the lung of a warm-blooded animal maintains surprising temperature stability despite the large difference between core temperature and inhaled air temperature.

High-temperature sensor

DOEpatents

Not Available

1981-01-29

A high temperature sensor is described which includes a pair of electrical conductors separated by a mass of electrical insulating material. The insulating material has a measurable resistivity within the sensor that changes in relation to the temperature of the insulating material within a high temperature range (1000 to 2000/sup 0/K). When required, the sensor can be encased within a ceramic protective coating.

Resistive oxygen sensor using ceria-zirconia sensor material and ceria-yttria temperature compensating material for lean-burn engine.

PubMed

Izu, Noriya; Nishizaki, Sayaka; Shin, Woosuck; Itoh, Toshio; Nishibori, Maiko; Matsubara, Ichiro

2009-01-01

Temperature compensating materials were investigated for a resistive oxygen sensor using Ce(0.9)Zr(0.1)O(2) as a sensor material for lean-burn engines. The temperature dependence of a temperature compensating material should be the same as the sensor material; therefore, the Y concentration in CeO(2)-Y(2)O(3) was optimized. The resistance of Ce(0.5)Y(0.5)O(2-δ) was independent of the air-to-fuel ratio (oxygen partial pressure), so that it was confirmed to function as a temperature compensating material. Sensor elements comprised of Ce(0.9)Zr(0.1)O(2) and Ce(0.5)Y(0.5)O(2-δ) were fabricated and the output was determined to be approximately independent of the temperature in the wide range from 773 to 1,073 K.

Temperature Sensor

NASA Technical Reports Server (NTRS)

1980-01-01

Weed Instrument Inc. produces a line of thermocouples - temperature sensors - for a variety of industrial and research uses. One of the company's newer products is a thermocouple specially designed for high accuracy at extreme temperatures above 3,000 degrees Fahrenheit. Development of sensor brought substantial increases in Weed Instrument sales and employment.

Cavity Ring-Down Absorption of O2 in Air as a Temperature Sensor for an Open and a Cryogenic Optical Cavity.

PubMed

Nyaupane, Parashu R; Perez-Delgado, Yasnahir; Camejo, David; Wright, Lesley M; Manzanares, Carlos E

2017-05-01

The A-band of oxygen has been measured at low resolution at temperatures between 90 K and 373 K using the phase shift cavity ring down (PS-CRD) technique. For temperatures between 90 K and 295 K, the PS-CRD technique presented here involves an optical cavity attached to a cryostat. The static cell and mirrors of the optical cavity are all inside a vacuum chamber at the same temperature of the cryostat. The temperature of the cell can be changed between 77 K and 295 K. For temperatures above 295 K, a hollow glass cylindrical tube without windows has been inserted inside an optical cavity to measure the temperature of air flowing through the tube. The cavity consists of two highly reflective mirrors which are mounted parallel to each other and separated by a distance of 93 cm. In this experiment, air is passed through a heated tube. The temperature of the air flowing through the tube is determined by measuring the intensity of the oxygen absorption as a function of the wavenumber. The A-band of oxygen is measured between 298 K and 373 K, with several air flow rates. To obtain the temperature, the energy of the lower rotational state for seven selected rotational transitions is linearly fitted to a logarithmic function that contains the relative intensity of the rotational transition, the initial and final rotational quantum numbers, and the energy of the transition. Accuracy of the temperature measurement is determined by comparing the calculated temperature from the spectra with the temperature obtained from a calibrated thermocouple inserted at the center of the tube. This flowing air temperature sensor will be used to measure the temperatures of cooling air at the input (cold air) and output (hot air) after cooling the blades of a laboratory gas turbine. The results could contribute to improvements in turbine blade cooling design.

Temperature-programmed technique accompanied with high-throughput methodology for rapidly searching the optimal operating temperature of MOX gas sensors.

PubMed

Zhang, Guozhu; Xie, Changsheng; Zhang, Shunping; Zhao, Jianwei; Lei, Tao; Zeng, Dawen

2014-09-08

A combinatorial high-throughput temperature-programmed method to obtain the optimal operating temperature (OOT) of gas sensor materials is demonstrated here for the first time. A material library consisting of SnO2, ZnO, WO3, and In2O3 sensor films was fabricated by screen printing. Temperature-dependent conductivity curves were obtained by scanning this gas sensor library from 300 to 700 K in different atmospheres (dry air, formaldehyde, carbon monoxide, nitrogen dioxide, toluene and ammonia), giving the OOT of each sensor formulation as a function of the carrier and analyte gases. A comparative study of the temperature-programmed method and a conventional method showed good agreement in measured OOT.

Computational fluid dynamics analysis and experimental study of a low measurement error temperature sensor used in climate observation.

PubMed

Yang, Jie; Liu, Qingquan; Dai, Wei

2017-02-01

To improve the air temperature observation accuracy, a low measurement error temperature sensor is proposed. A computational fluid dynamics (CFD) method is implemented to obtain temperature errors under various environmental conditions. Then, a temperature error correction equation is obtained by fitting the CFD results using a genetic algorithm method. The low measurement error temperature sensor, a naturally ventilated radiation shield, a thermometer screen, and an aspirated temperature measurement platform are characterized in the same environment to conduct the intercomparison. The aspirated platform served as an air temperature reference. The mean temperature errors of the naturally ventilated radiation shield and the thermometer screen are 0.74 °C and 0.37 °C, respectively. In contrast, the mean temperature error of the low measurement error temperature sensor is 0.11 °C. The mean absolute error and the root mean square error between the corrected results and the measured results are 0.008 °C and 0.01 °C, respectively. The correction equation allows the temperature error of the low measurement error temperature sensor to be reduced by approximately 93.8%. The low measurement error temperature sensor proposed in this research may be helpful to provide a relatively accurate air temperature result.

Design and evaluation of an inexpensive radiation shield for monitoring surface air temperatures

Treesearch

Zachary A. Holden; Anna E. Klene; Robert F. Keefe; Gretchen G. Moisen

2013-01-01

Inexpensive temperature sensors are widely used in agricultural and forestry research. This paper describes a low-cost (~3 USD) radiation shield (radshield) designed for monitoring surface air temperatures in harsh outdoor environments. We compared the performance of the radshield paired with low-cost temperature sensors at three sites in western Montana to several...

Impact of Temperature and UV Irradiation on Dynamics of NO2 Sensors Based on ZnO Nanostructures

PubMed Central

Pustelny, Tadeusz

2017-01-01

The main object of this study is the improvement of the dynamics of NO2 sensors based on ZnO nanostructures. Investigations presented in this paper showed that the combination of temperature and ultraviolet (UV) activation of the sensors can significantly decrease the sensor response and regeneration times. In comparison with the single activation method (elevated temperature or UV), these times for 1 ppm of NO2 decreased from about 10 min (or more) to less than 40 s. In addition, at the optimal conditions (200 °C and UV), sensors were very stable, were fully scalable (in the range on NO2 concentration of 1–20 ppm) and baseline drift was significantly reduced. Furthermore, in this paper, extensive studies of the influence of temperature and carrier gas (nitrogen and air) on NO2 sensing properties of the ZnO nanostructures were conducted. The NO2 sensing mechanisms of the sensors operating at elevated temperatures and under UV irradiation were also discussed. Our study showed that sensor responses to NO2 and response/regeneration times are comparable from sensor to sensor in air and nitrogen conditions, which suggests that the proposed simple technology connected with well-chosen operation conditions is repeatable. The estimated limit of detection of the sensors is within the level of ≈800 ppb in nitrogen and ≈700 ppb in air. PMID:29019924

Comparison of neonatal skin sensor temperatures with axillary temperature: does skin sensor placement really matter?

PubMed

Schafer, Dorothea; Boogaart, Sheri; Johnson, Lynette; Keezel, Catherine; Ruperts, Liga; Vander Laan, Karen J

2014-02-01

Appropriate thermoregulation affects both morbidity and mortality in the neonatal setting. Nurses rely on information from temperature sensors and radiant warmers or incubators to appropriately maintain a neonate's body temperature. Skin temperature sensors must be repositioned to prevent skin irritation and breakdown. This study addresses whether there is a significant difference between skin sensor temperature readings from 3 locations on the neonate and whether there is a significant difference between skin sensor temperatures compared with digital axillary temperatures. The study participants included 36 hemodynamically stable neonates, with birth weight of 750 g or more and postnatal age of 15 days or more, in a neonatal intensive care unit. Gestational age ranged from 29.6 to 36.1 weeks at the time of data collection. A method-comparison design was used to evaluate the level of agreement between skin sensor temperatures and digital axillary thermometer measurements. When the neonate's skin sensor was scheduled for routine site change, 3 new skin sensors were placed-1 each on the right upper abdomen, left flank, and right axilla. The neonate was placed in a supine position and redressed or rewrapped if previously dressed or wrapped. Subjects served as their own controls, with temperatures measured at all 3 skin sensor sites and followed by a digital thermometer measurement in the left axilla. The order of skin sensor temperature measurements was randomly assigned by a computer-generated number sequence. An analysis of variance for repeated measures was used to test for statistical differences between the skin sensor temperatures. The difference in axillary and skin sensor temperatures was calculated by subtracting the reference standard temperature (digital axillary) from the test temperatures (skin temperatures at 3 different locations), using the Bland-Altman method. The level of significance was set at P < .05. No statistically significant differences were

An airborne sensor for the avoidance of clear air turbulence

NASA Technical Reports Server (NTRS)

Gary, B. L.

1981-01-01

This paper describes an airborne microwave radiometer that may be able to provide altitude guidance away from layers containing clear air turbulence, CAT. The sensor may also be able to predict upper limits for the severity of upcoming CAT. The 55 GHz radiometer is passive, not radar, and it measures the temperature of oxygen molecules in the viewing direction (averaged along a several-kilometer path). A small computer directs the viewing direction through elevation angle scans, and converts observed quantities to an 'altitude temperature profile'. The principle for CAT avoidance is that CAT is found statistically more often within inversion layers and at the tropopause, both of which are easily located from sensor-generated altitude temperature profiles.

Fiber Optic Distributed Sensors for High-resolution Temperature Field Mapping.

PubMed

Lomperski, Stephen; Gerardi, Craig; Lisowski, Darius

2016-11-07

The reliability of computational fluid dynamics (CFD) codes is checked by comparing simulations with experimental data. A typical data set consists chiefly of velocity and temperature readings, both ideally having high spatial and temporal resolution to facilitate rigorous code validation. While high resolution velocity data is readily obtained through optical measurement techniques such as particle image velocimetry, it has proven difficult to obtain temperature data with similar resolution. Traditional sensors such as thermocouples cannot fill this role, but the recent development of distributed sensing based on Rayleigh scattering and swept-wave interferometry offers resolution suitable for CFD code validation work. Thousands of temperature measurements can be generated along a single thin optical fiber at hundreds of Hertz. Sensors function over large temperature ranges and within opaque fluids where optical techniques are unsuitable. But this type of sensor is sensitive to strain and humidity as well as temperature and so accuracy is affected by handling, vibration, and shifts in relative humidity. Such behavior is quite unlike traditional sensors and so unconventional installation and operating procedures are necessary to ensure accurate measurements. This paper demonstrates implementation of a Rayleigh scattering-type distributed temperature sensor in a thermal mixing experiment involving two air jets at 25 and 45 °C. We present criteria to guide selection of optical fiber for the sensor and describe installation setup for a jet mixing experiment. We illustrate sensor baselining, which links readings to an absolute temperature standard, and discuss practical issues such as errors due to flow-induced vibration. This material can aid those interested in temperature measurements having high data density and bandwidth for fluid dynamics experiments and similar applications. We highlight pitfalls specific to these sensors for consideration in experiment design

Application of Artificial Neural Networks to the Development of Improved Multi-Sensor Retrievals of Near-Surface Air Temperature and Humidity Over Ocean

NASA Technical Reports Server (NTRS)

Roberts, J. Brent; Robertson, Franklin R.; Clayson, Carol Anne

2012-01-01

Improved estimates of near-surface air temperature and air humidity are critical to the development of more accurate turbulent surface heat fluxes over the ocean. Recent progress in retrieving these parameters has been made through the application of artificial neural networks (ANN) and the use of multi-sensor passive microwave observations. Details are provided on the development of an improved retrieval algorithm that applies the nonlinear statistical ANN methodology to a set of observations from the Advanced Microwave Scanning Radiometer (AMSR-E) and the Advanced Microwave Sounding Unit (AMSU-A) that are currently available from the NASA AQUA satellite platform. Statistical inversion techniques require an adequate training dataset to properly capture embedded physical relationships. The development of multiple training datasets containing only in-situ observations, only synthetic observations produced using the Community Radiative Transfer Model (CRTM), or a mixture of each is discussed. An intercomparison of results using each training dataset is provided to highlight the relative advantages and disadvantages of each methodology. Particular emphasis will be placed on the development of retrievals in cloudy versus clear-sky conditions. Near-surface air temperature and humidity retrievals using the multi-sensor ANN algorithms are compared to previous linear and non-linear retrieval schemes.

Highlights from the Air Sensors 2014 Workshop

EPA Science Inventory

In June 2014, the U.S. Environmental Protection Agency (EPA) hosted its fourth next-generation air monitoring workshop to discuss the current state of the science in air sensor technologies and their applications for environmental monitoring, Air Sensors 2014: A New Frontier. Th...

Community Air Sensor Network CAIRSENSE Project: Lower ...

EPA Pesticide Factsheets

Presentation slides on the CAIRSENSE project, Atlanta field study testing low cost air sensors against FEM instruments. To be presented at the Air and Waste Management Association conference. Presentation slides on the CAIRSENSE project, Atlanta field study testing low cost air sensors against FEM instruments. To be presented at the Air and Waste Management Association conference.

Comparison of Near-Surface Air Temperatures and MODIS Ice-Surface Temperatures at Summit, Greenland (2008-2013)

NASA Technical Reports Server (NTRS)

Shuman, Christopher A.; Hall, Dorothy K.; DiGirolamo, Nicolo E.; Mefford, Thomas K.; Schnaubelt, Michael J.

2014-01-01

We have investigated the stability of the MODerate resolution Imaging Spectroradiometer (MODIS) infrared-derived ice surface temperature (IST) data from Terra for use as a climate quality data record. The availability of climate quality air temperature data (TA) from a NOAA Global Monitoring Division observatory at Greenlands Summit station has enabled this high temporal resolution study of MODIS ISTs. During a 5 year period (July 2008 to August 2013), more than 2500 IST values were compared with 3-minute average TA values derived from the 1-minute data from NOAAs primary 2 m air temperature sensor. These data enabled an expected small offset between air and surface temperatures at this the ice sheet location to be investigated over multiple annual cycles.

Air Conditioning Overflow Sensor

NASA Technical Reports Server (NTRS)

1996-01-01

The Technology Transfer Office at Stennis Space Center helped a local inventor develop a prototype of an attachment for central air conditioners and heat pumps that helps monitor water levels to prevent condensation overflow. The sensor will indicate a need for drain line maintenance and prevent possible damage caused by drain pan water spillover. An engineer in the Stennis Space Center prototype Development Laboratory used SSC sensor technology in the development of the sensor.

Comparison of MODIS-derived land surface temperature with air temperature measurements

NASA Astrophysics Data System (ADS)

Georgiou, Andreas; Akçit, Nuhcan

2017-09-01

Air surface temperature is an important parameter for a wide range of applications such as agriculture, hydrology and climate change studies. Air temperature data is usually obtained from measurements made in meteorological stations, providing only limited information about spatial patterns over wide areas. The use of remote sensing data can help overcome this problem, particularly in areas with low station density, having the potential to improve the estimation of air surface temperature at both regional and global scales. Land Surface (skin) Temperatures (LST) derived from Moderate Resolution Imaging Spectroradiometer (MODIS) sensor aboard the Terra and Aqua satellite platforms provide spatial estimates of near-surface temperature values. In this study, LST values from MODIS are compared to groundbased near surface air (Tair) measurements obtained from 14 observational stations during 2011 to 2015, covering coastal, mountainous and urban areas over Cyprus. Combining Terra and Aqua LST-8 Day and Night acquisitions into a mean monthly value, provide a large number of LST observations and a better overall agreement with Tair. Comparison between mean monthly LSTs and mean monthly Tair for all sites and all seasons pooled together yields a very high correlation and biases. In addition, the presented high standard deviation can be explained by the influence of surface heterogeneity within MODIS 1km2 grid cells, the presence of undetected clouds and the inherent difference between LST and Tair. However, MODIS LST data proved to be a reliable proxy for surface temperature and mostly for studies requiring temperature reconstruction in areas with lack of observational stations.

Laser photoacoustic sensor for air toxicity measurements

NASA Astrophysics Data System (ADS)

Prasad, Coorg R.; Lei, Jie; Shi, Wenhui; Li, Guangkun; Dunayevskiy, Ilya; Patel, C. Kumar N.

2012-06-01

US EPA's Clean Air Act lists 187 hazardous air pollutants (HAP) or airborne toxics that are considered especially harmful to health, and hence the measurement of their concentration is of great importance. Numerous sensor systems have been reported for measuring these toxic gases and vapors. However, most of these sensors are specific to a single gas or able to measure only a few of them. Thus a sensor capable of measuring many of the toxic gases simultaneously is desirable. Laser photoacoustic spectroscopy (LPAS) sensors have the potential for true broadband measurement when used in conjunction with one or more widely tunable laser sources. An LPAS gas analyzer equipped with a continuous wave, room temperature IR Quantum Cascade Laser tunable over the wavelength range of 9.4 μm to 9.7 μm was used for continuous real-time measurements of multiple gases/chemical components. An external cavity grating tuner was used to generate several (75) narrow line output wavelengths to conduct photoacoustic absorption measurements of gas mixtures. We have measured various HAPs such as Benzene, Formaldehyde, and Acetaldehyde in the presence of atmospheric interferents water vapor, and carbon dioxide. Using the preliminary spectral pattern recognition algorithm, we have shown our ability to measure all these chemical compounds simultaneously in under 3 minutes. Sensitivity levels of a few part-per-billion (ppb) were achieved with several of the measured compounds with the preliminary laboratory system.

Overview of Emerging Air Sensors

EPA Science Inventory

These slides will be presented at the 2014 National Ambient Air Monitoring Conference in Atlanta, GA during August 11-15, 2014. The goal is to provide an overview of air sensor technology and the audience will be primarily state air monitoring agencies and EPA Regions.

Fiber optic temperature sensor

NASA Technical Reports Server (NTRS)

Quick, William H. (Inventor); August, Rudolf R. (Inventor); James, Kenneth A. (Inventor); Strahan, Jr., Virgil H. (Inventor); Nichols, Donald K. (Inventor)

1980-01-01

An inexpensive, lightweight fiber optic micro-sensor that is suitable for applications which may require remote temperature sensing. The disclosed temperature sensor includes a phosphor material that, after receiving incident light stimulation, is adapted to emit phosphorescent radiation output signals, the amplitude decay rate and wavelength of which are functions of the sensed temperature.

High-Temperature Optical Sensor

NASA Technical Reports Server (NTRS)

Adamovsky, Grigory; Juergens, Jeffrey R.; Varga, Donald J.; Floyd, Bertram M.

2010-01-01

A high-temperature optical sensor (see Figure 1) has been developed that can operate at temperatures up to 1,000 C. The sensor development process consists of two parts: packaging of a fiber Bragg grating into a housing that allows a more sturdy thermally stable device, and a technological process to which the device is subjected to in order to meet environmental requirements of several hundred C. This technology uses a newly discovered phenomenon of the formation of thermally stable secondary Bragg gratings in communication-grade fibers at high temperatures to construct robust, optical, high-temperature sensors. Testing and performance evaluation (see Figure 2) of packaged sensors demonstrated operability of the devices at 1,000 C for several hundred hours, and during numerous thermal cycling from 400 to 800 C with different heating rates. The technology significantly extends applicability of optical sensors to high-temperature environments including ground testing of engines, flight propulsion control, thermal protection monitoring of launch vehicles, etc. It may also find applications in such non-aerospace arenas as monitoring of nuclear reactors, furnaces, chemical processes, and other hightemperature environments where other measurement techniques are either unreliable, dangerous, undesirable, or unavailable.

A local sensor for joint temperature and velocity measurements in turbulent flows

NASA Astrophysics Data System (ADS)

Salort, Julien; Rusaouën, Éléonore; Robert, Laurent; du Puits, Ronald; Loesch, Alice; Pirotte, Olivier; Roche, Philippe-E.; Castaing, Bernard; Chillà, Francesca

2018-01-01

We present the principle for a micro-sensor aimed at measuring local correlations of turbulent velocity and temperature. The operating principle is versatile and can be adapted for various types of flow. It is based on a micro-machined cantilever, on the tip of which a platinum resistor is patterned. The deflection of the cantilever yields an estimate for the local velocity, and the impedance of the platinum yields an estimate for the local temperature. The velocity measurement is tested in two turbulent jets: one with air at room temperature which allows us to compare with well-known calibrated reference anemometers, and another one in the GReC jet at CERN with cryogenic gaseous helium which allows a much larger range of resolved turbulent scales. The recording of temperature fluctuations is tested in the Barrel of Ilmenau which provides a controlled turbulent thermal flow in air. Measurements in the wake of a heated or cooled cylinder demonstrate the capability of the sensor to display the cross correlation between temperature and velocity correctly.

Development of a Wireless Network of Temperature Sensors for Yellowstone National Park (USA)

NASA Astrophysics Data System (ADS)

Munday, D. A.; Hutter, T.; Minolli, M.; Obraczka, K.; Manduchi, R.; Petersen, S.; Lowenstern, J. B.; Heasler, H.

2007-12-01

Temperature sensors deployed at Yellowstone clearly document that thermal features can vary in temperature on a variety of timescales and show regional correlations unrelated to meteorological variables such as air temperature. Yellowstone National Park (YNP) staff currently measures temperatures at over 40 thermal features and streams within the park, utilizing USGS stream gaging stations and portable data loggers deployed in geyser basins. The latter measure temperature every 1 to 15 minutes, and the data are physically downloaded after about 30 days. Installation of a wireless sensor network would: 1) save considerable time and effort in data retrieval, 2) minimize lost data due to equipment failure, and 3) provide a means to monitor thermal perturbations in near-real time. To meet this need, we developed a wireless sensor network capable of in-situ monitoring of air and water temperature. Temperature sensors are dispersed as nodes that communicate among themselves and through relays to a single base-station linked to the Internet. The small, weatherproof sensors operate unattended for over six months at temperatures as low as -40°C. Each uses an ultra-low-power Texas Instruments' MSP430 microcontroller and an SD card as mass storage. They are powered by 15Ah, 3.6 v, inert Li-ion batteries and transmit data via 900MHz radio modules with a 1-km range. The initial prototype consists of 4 nodes, and is designed to scale with additional nodes for finer spatial resolution and broader coverage. Temperature measurements are asynchronous from node to node, with intervals as frequent as 30 seconds. Data are stored internally to withstand temporary communication failures; underlying intelligent software is capable of re-routing data through alternative nodes to the base station and a MySQL data archiving system. We also developed a Google-Maps-based, front-end that displays the data, recent trends and sensor locations. The system was tested in the Santa Cruz Mountains

Apparatus and Method for Measuring Air Temperature Ahead of an Aircraft for Controlling a Variable Inlet/Engine Assembly

NASA Technical Reports Server (NTRS)

Gary, Bruce L. (Inventor)

2001-01-01

The apparatus and method employ remote sensing to measure the air temperature a sufficient distance ahead of the aircraft to allow time for a variable inlet/engine assembly to be reconfigured in response to the measured temperature, to avoid inlet unstart and/or engine compressor stall. In one embodiment, the apparatus of the invention has a remote sensor for measuring at least one air temperature ahead of the vehicle and an inlet control system for varying the inlet. The remote sensor determines a change in temperature value using at least one temperature measurement and prior temperature measurements corresponding to the location of the aircraft. The control system uses the change in air temperature value to vary the inlet configuration to maintain the position of the shock wave during the arrival of the measured air in the inlet. In one embodiment, the method of the invention includes measuring at least one air temperature ahead of the vehicle, determining an air temperature at the vehicle from prior air temperature measurements, determining a change in temperature value using the air temperature at the vehicle and the at least one air temperature measurement ahead of the vehicle, and using the change in temperature value to-reposition the airflow inlet, to cause the shock wave to maintain substantially the same position within the inlet as the airflow temperature changes within the inlet.

Hollow glass microsphere-structured Fabry-Perot interferometric sensor for highly sensitive temperature measurement

NASA Astrophysics Data System (ADS)

Cheng, Junna; Zhou, Ciming; Fan, Dian; Ou, Yiwen

2017-04-01

We propose and demonstrate a miniature Fabry-Perot (F-P) interferometric sensor based on a hollow glass microsphere (HGM) for highly sensitive temperature measurement. The sensor head is fabricated by sticking a HGM on the end face of a single-mode fiber, and it consists of a short air F-P cavity between the front and the rear surfaces of the HGM. A sensor with 135.7280-μm cavity length was tested for temperature measurement from -5 °C to 50 °C. The obtained sensitivity reached up to 24.5 pm/°C and the variation rate of the HGM- F-P's cavity length was2.1 nm/°C. The advantages of compact size, easy fabrication and low cost make the sensor suitable for highly sensitive temperature sensing.

Rare Earth Optical Temperature Sensor

NASA Technical Reports Server (NTRS)

Chubb, Donald L.; Wolford, David S.

2000-01-01

A new optical temperature sensor suitable for high temperatures (greater than 1700 K) and harsh environments is introduced. The key component of the sensor is the rare earth material contained at the end of a sensor that is in contact with the sample being measured. The measured narrow wavelength band emission from the rare earth is used to deduce the sample temperature. A simplified relation between the temperature and measured radiation was verified experimentally. The upper temperature limit of the sensor is determined by material limits to be approximately 2000 C. The lower limit, determined by the minimum detectable radiation, is found to be approximately 700 K. At high temperatures 1 K resolution is predicted. Also, millisecond response times are calculated.

Temperature insensitive bending sensor based on in-line Mach-Zehnder interferometer

NASA Astrophysics Data System (ADS)

Chen, Xue; Yu, Yongqin; Xu, Xiaomei; Huang, Quandong; Ou, Zhilong; Wang, Jishun; Yan, Peiguang; Du, Chenlin

2014-09-01

A simple and compact fiber bending sensor based on the Mach-Zehnder interferometer was proposed. A photonic crystal fiber (PCF) with a length of 10 mm was spliced by collapsing air holes with two conventional single mode fibers to consist of an all fiber bending sensor. The sensitivity of 0.53 nm/m-1 was obtained at 1586 nm for the curvature range from 0 to 8.514 m-1. The temperature sensitivity was very low. The measurement error due to the temperature effect was about 8.68×10-3 m-1/°c, and the temperature effect in the curvature measurement could be ignored. This device can avoid the cross sensitivity of the temperature in the curvature measurement.

Fluidic Sensor Temperature Indicating System.

DTIC Science & Technology

A fluidic sensor temperature indicating system designed by Honeywell Inc was tested on a T56 engine during dynamometer calibration. It was also...based on the sensor being mounted in a T56 engine showed a hot gas temperature drop from 1970F at the sensor entrance to 1760F in the sensor pulsation

A Neural Network Based Intelligent Predictive Sensor for Cloudiness, Solar Radiation and Air Temperature

PubMed Central

Ferreira, Pedro M.; Gomes, João M.; Martins, Igor A. C.; Ruano, António E.

2012-01-01

Accurate measurements of global solar radiation and atmospheric temperature, as well as the availability of the predictions of their evolution over time, are important for different areas of applications, such as agriculture, renewable energy and energy management, or thermal comfort in buildings. For this reason, an intelligent, light-weight and portable sensor was developed, using artificial neural network models as the time-series predictor mechanisms. These have been identified with the aid of a procedure based on the multi-objective genetic algorithm. As cloudiness is the most significant factor affecting the solar radiation reaching a particular location on the Earth surface, it has great impact on the performance of predictive solar radiation models for that location. This work also represents one step towards the improvement of such models by using ground-to-sky hemispherical colour digital images as a means to estimate cloudiness by the fraction of visible sky corresponding to clouds and to clear sky. The implementation of predictive models in the prototype has been validated and the system is able to function reliably, providing measurements and four-hour forecasts of cloudiness, solar radiation and air temperature. PMID:23202230

Characterization of measurement artefacts in fluoroptic temperature sensors: implications for laser thermal therapy at 810 nm.

PubMed

Davidson, Sean R H; Vitkin, I Alex; Sherar, Michael D; Whelan, William M

2005-04-01

Fluoroptic sensors are used to measure interstitial temperatures but their utility for monitoring laser interstitial thermal therapy (LITT) is unclear because these sensors exhibit a measurement artefact when exposed to the near-infrared (NIR) treatment light. This study investigates the cause of the artefact to determine whether fluoroptic sensors can provide reliable temperature measurements during LITT. The temperature rise measured by a fluoroptic sensor irradiated in non-absorbing media (air and water) was considered an artefact. Temperature rise was measured as a function of distance from a laser source. Two different sensor designs and several laser powers were investigated. A relationship between fluence rate and measurement artefact in water was determined and coupled with a numerical simulation of LITT in liver to estimate the error in temperature measurements made by fluoroptic sensors in tissue in proximity to the laser source. The effect of ambient light on the performance of sensors capped with a transparent material ("clear-capped sensors") was also investigated. The temperature rise recorded in air by both clear- and black-capped fluoroptic sensors decreased with distance from a laser source in a manner similar to fluence rate. Sensor cap material, laser power, and the thermal properties of the surrounding medium affected the magnitude of the artefact. Numerical simulations indicated that the accuracy of a clear-capped fluoroptic sensor used to monitor a typical LITT treatment in liver is > 1 degrees C provided the sensor is further than approximately 3 mm from the source. It was also shown that clear-capped fluoroptic sensors are affected by ambient light. The measurement artefact experienced by both black-capped and clear-capped fluoroptic sensors irradiated by NIR light scales with fluence rate and is due to direct absorption of the laser light, which results in sensor self-heating. Clear-capped fluoroptic sensors can be used to accurately

Community Air Sensor Network (CAIRSENSE) project: evaluation of low-cost sensor performance in a suburban environment in the southeastern United States

NASA Astrophysics Data System (ADS)

Jiao, Wan; Hagler, Gayle; Williams, Ronald; Sharpe, Robert; Brown, Ryan; Garver, Daniel; Judge, Robert; Caudill, Motria; Rickard, Joshua; Davis, Michael; Weinstock, Lewis; Zimmer-Dauphinee, Susan; Buckley, Ken

2016-11-01

Advances in air pollution sensor technology have enabled the development of small and low-cost systems to measure outdoor air pollution. The deployment of a large number of sensors across a small geographic area would have potential benefits to supplement traditional monitoring networks with additional geographic and temporal measurement resolution, if the data quality were sufficient. To understand the capability of emerging air sensor technology, the Community Air Sensor Network (CAIRSENSE) project deployed low-cost, continuous, and commercially available air pollution sensors at a regulatory air monitoring site and as a local sensor network over a surrounding ˜ 2 km area in the southeastern United States. Collocation of sensors measuring oxides of nitrogen, ozone, carbon monoxide, sulfur dioxide, and particles revealed highly variable performance, both in terms of comparison to a reference monitor as well as the degree to which multiple identical sensors produced the same signal. Multiple ozone, nitrogen dioxide, and carbon monoxide sensors revealed low to very high correlation with a reference monitor, with Pearson sample correlation coefficient (r) ranging from 0.39 to 0.97, -0.25 to 0.76, and -0.40 to 0.82, respectively. The only sulfur dioxide sensor tested revealed no correlation (r < 0.5) with a reference monitor and erroneously high concentration values. A wide variety of particulate matter (PM) sensors were tested with variable results - some sensors had very high agreement (e.g., r = 0.99) between identical sensors but moderate agreement with a reference PM2.5 monitor (e.g., r = 0.65). For select sensors that had moderate to strong correlation with reference monitors (r > 0.5), step-wise multiple linear regression was performed to determine if ambient temperature, relative humidity (RH), or age of the sensor in number of sampling days could be used in a correction algorithm to improve the agreement. Maximum improvement in agreement with a reference

High-Density, High-Resolution, Low-Cost Air Quality Sensor Networks for Urban Air Monitoring

NASA Astrophysics Data System (ADS)

Mead, M. I.; Popoola, O. A.; Stewart, G.; Bright, V.; Kaye, P.; Saffell, J.

2012-12-01

, temperature, relative humidity, wind speed and direction. The network incorporates existing GPRS infrastructures for real time sending of data with low overheads in terms of cost, effort and installation. In this paper we present data from the SNAQ Heathrow project as well as previous deployments showing measurement capability at the ppb level for NO, NO2 and CO. We show that variability can be observed and measured quantitatively using these sensor networks over widely differing time scales from individual emission events, diurnal variability associated with traffic and meteorological conditions, through to longer term synoptic weather conditions and seasonal behaviour. This work demonstrates a widely applicable generic capability to urban areas, airports as well as other complex emissions environments making this sensor system methodology valuable for scientific, policy and regulatory issues. We conclude that the low-cost high-density network philosophy has the potential to provide a more complete assessment of the high-granularity air quality structure generally observed in the environment. Further, when appropriately deployed, has the potential to offer a new paradigm in air quality quantification and monitoring.

Microhotplate Temperature Sensor Calibration and BIST.

PubMed

Afridi, M; Montgomery, C; Cooper-Balis, E; Semancik, S; Kreider, K G; Geist, J

2011-01-01

In this paper we describe a novel long-term microhotplate temperature sensor calibration technique suitable for Built-In Self Test (BIST). The microhotplate thermal resistance (thermal efficiency) and the thermal voltage from an integrated platinum-rhodium thermocouple were calibrated against a freshly calibrated four-wire polysilicon microhotplate-heater temperature sensor (heater) that is not stable over long periods of time when exposed to higher temperatures. To stress the microhotplate, its temperature was raised to around 400 °C and held there for days. The heater was then recalibrated as a temperature sensor, and microhotplate temperature measurements were made based on the fresh calibration of the heater, the first calibration of the heater, the microhotplate thermal resistance, and the thermocouple voltage. This procedure was repeated 10 times over a period of 80 days. The results show that the heater calibration drifted substantially during the period of the test while the microhotplate thermal resistance and the thermocouple-voltage remained stable to within about plus or minus 1 °C over the same period. Therefore, the combination of a microhotplate heater-temperature sensor and either the microhotplate thermal resistance or an integrated thin film platinum-rhodium thermocouple can be used to provide a stable, calibrated, microhotplate-temperature sensor, and the combination of the three sensor is suitable for implementing BIST functionality. Alternatively, if a stable microhotplate-heater temperature sensor is available, such as a properly annealed platinum heater-temperature sensor, then the thermal resistance of the microhotplate and the electrical resistance of the platinum heater will be sufficient to implement BIST. It is also shown that aluminum- and polysilicon-based temperature sensors, which are not stable enough for measuring high microhotplate temperatures (>220 °C) without impractically frequent recalibration, can be used to measure the

Microhotplate Temperature Sensor Calibration and BIST

PubMed Central

Afridi, M.; Montgomery, C.; Cooper-Balis, E.; Semancik, S.; Kreider, K. G.; Geist, J.

2011-01-01

In this paper we describe a novel long-term microhotplate temperature sensor calibration technique suitable for Built-In Self Test (BIST). The microhotplate thermal resistance (thermal efficiency) and the thermal voltage from an integrated platinum-rhodium thermocouple were calibrated against a freshly calibrated four-wire polysilicon microhotplate-heater temperature sensor (heater) that is not stable over long periods of time when exposed to higher temperatures. To stress the microhotplate, its temperature was raised to around 400 °C and held there for days. The heater was then recalibrated as a temperature sensor, and microhotplate temperature measurements were made based on the fresh calibration of the heater, the first calibration of the heater, the microhotplate thermal resistance, and the thermocouple voltage. This procedure was repeated 10 times over a period of 80 days. The results show that the heater calibration drifted substantially during the period of the test while the microhotplate thermal resistance and the thermocouple-voltage remained stable to within about plus or minus 1 °C over the same period. Therefore, the combination of a microhotplate heater-temperature sensor and either the microhotplate thermal resistance or an integrated thin film platinum-rhodium thermocouple can be used to provide a stable, calibrated, microhotplate-temperature sensor, and the combination of the three sensor is suitable for implementing BIST functionality. Alternatively, if a stable microhotplate-heater temperature sensor is available, such as a properly annealed platinum heater-temperature sensor, then the thermal resistance of the microhotplate and the electrical resistance of the platinum heater will be sufficient to implement BIST. It is also shown that aluminum- and polysilicon-based temperature sensors, which are not stable enough for measuring high microhotplate temperatures (>220 °C) without impractically frequent recalibration, can be used to measure the

Urban air quality measurements using a sensor-based system

NASA Astrophysics Data System (ADS)

Ródenas, Mila; Hernández, Daniel; Gómez, Tatiana; López, Ramón; Muñoz, Amalia

2017-04-01

Air pollution levels in urban areas have increased the interest, not only of the scientific community but also of the general public, and both at the regional and at the European level. This interest has run in parallel to the development of miniaturized sensors, which only since very recently are suitable for air quality measurements. Certainly, their small size and price allows them to be used as a network of sensors capable of providing high temporal and spatial frequency measurements to characterize an area or city and with increasing potential, under certain considerations, as a complement of conventional methods. Within the frame of the LIFE PHOTOCITYTEX project (use of photocatalytic textiles to help reducing air pollution), CEAM has developed a system to measure gaseous compounds of importance for urban air quality characterization. This system, which allows an autonomous power supply, uses commercial NO, NO2, O3 and CO2 small sensors and incorporates measurements of temperature and humidity. A first version, using XBee boards (Radiofrequency) for communications has been installed in the urban locations defined by the project (tunnel and school), permitting the long-term air quality characterization of sites in the presence of the textiles. An improved second version of the system which also comprises a sensor for measuring particles and which uses GPRS for communications, has been developed and successfully installed in the city center of Valencia. Data are sent to a central server where they can be accessed by citizens in nearly real time and online and, in general, they can be utilized in the air quality characterization, for decision-making related to decontamination (traffic regulation, photocatalytic materials, etc.), in air quality models or in mobile applications of interest for the citizens. Within this work, temporal trends obtained with this system in different urban locations will be shown, discussing the impact of the characteristics of the

Noncontact Monitoring of Respiration by Dynamic Air-Pressure Sensor.

PubMed

Takarada, Tohru; Asada, Tetsunosuke; Sumi, Yoshihisa; Higuchi, Yoshinori

2015-01-01

We have previously reported that a dynamic air-pressure sensor system allows respiratory status to be visually monitored for patients in minimally clothed condition. The dynamic air-pressure sensor measures vital information using changes in air pressure. To utilize this device in the field, we must clarify the influence of clothing conditions on measurement. The present study evaluated use of the dynamic air-pressure sensor system as a respiratory monitor that can reliably detect change in breathing patterns irrespective of clothing. Twelve healthy volunteers reclined on a dental chair positioned horizontally with the sensor pad for measuring air-pressure signals corresponding to respiration placed on the seat back of the dental chair in the central lumbar region. Respiratory measurements were taken under 2 conditions: (a) thinly clothed (subject lying directly on the sensor pad); and (b) thickly clothed (subject lying on the sensor pad covered with a pressure-reducing sheet). Air-pressure signals were recorded and time integration values for air pressure during each expiration were calculated. This information was compared with expiratory tidal volume measured simultaneously by a respirometer connected to the subject via face mask. The dynamic air-pressure sensor was able to receive the signal corresponding to respiration regardless of clothing conditions. A strong correlation was identified between expiratory tidal volume and time integration values for air pressure during each expiration for all subjects under both clothing conditions (0.840-0.988 for the thinly clothed condition and 0.867-0.992 for the thickly clothed condition). These results show that the dynamic air-pressure sensor is useful for monitoring respiratory physiology irrespective of clothing.

A mid-infrared laser absorption sensor for carbon monoxide and temperature measurements

NASA Astrophysics Data System (ADS)

Vanderover, Jeremy

A mid-infrared (mid-IR) absorption sensor based on quantum cascade laser (QCL) technology has been developed and demonstrated for high-temperature thermometry and carbon monoxide (CO) measurements in combustion environments. The sensor probes the high-intensity fundamental CO ro-vibrational band at 4.6 mum enabling sensitive measurement of CO and temperature at kHz acquisition rates. Because the sensor operates in the mid-IR CO fundamental band it is several orders of magnitude more sensitive than most of the previously developed CO combustion sensors which utilized absorption in the near-IR overtone bands and mature traditional telecommunications-based diode lasers. The sensor has been demonstrated and validated under operation in both scanned-wavelength absorption and wavelength-modulation spectroscopy (WMS) modes in room-temperature gas cell and high-temperature shock tube experiments with known and specified gas conditions. The sensor has also been demonstrated for CO and temperature measurements in an atmospheric premixed ethylene/air McKenna burner flat flame for a range of equivalence ratios (phi = 0.7-1.4). Demonstration of the sensor under scanned-wavelength direct absorption operation was performed in a room-temperature gas cell (297 K and 0.001-1 atm) allowing validation of the line strengths and line shapes predicted by the HITRAN 2004 spectroscopic database. Application of the sensor in scanned-wavelength mode, at 1-2 kHz acquisition bandwidths, to specified high-temperature shock-heated gases (950-3400 K, 1 atm) provided validation of the sensor for measurements under the high-temperature conditions found in combustion devices. The scanned-wavelength shock tube measurements yielded temperature determinations that deviated by only +/-1.2% (1-sigma deviation) with the reflected shock temperatures and CO mole fraction determinations that deviated by that specified CO mole fraction by only +/-1.5% (1-sigma deviation). These deviations are in fact smaller

The Benefits of Using Dense Temperature Sensor Networks to Monitor Urban Warming

NASA Astrophysics Data System (ADS)

Twine, T. E.; Snyder, P. K.; Kucharik, C. J.; Schatz, J.

2015-12-01

Urban heat islands (UHIs) occur when urban and suburban areas experience temperatures that are elevated relative to their rural surroundings because of differences in the fraction of gray and green infrastructure. Studies have shown that communities most at risk for impacts from climate-related disasters (i.e., lower median incomes, higher poverty, lower education, and minorities) tend to live in the hottest areas of cities. Development of adequate climate adaptation tools for cities relies on knowledge of how temperature varies across space and time. Traditionally, a city's urban heat island has been quantified using near-surface air temperature measurements from a few sites. This methodology assumes (1) that the UHI can be characterized by the difference in air temperature from a small number of points, and (2) that these few points represent the urban and rural signatures of the region. This methodology ignores the rich information that could be gained from measurements across the urban to rural transect. This transect could traverse elevations, water bodies, vegetation fraction, and other land surface properties. Two temperature sensor networks were designed and implemented in the Minneapolis-Saint Paul, MN and Madison, WI metropolitan areas beginning in 2011 and 2012, respectively. Both networks use the same model sensor and record temperature every 15 minutes from ~150 sensors. Data from each network has produced new knowledge of how temperature varies diurnally and seasonally across the cities and how the UHI magnitude is influenced by weather phenomena (e.g., wind, snow cover, heat waves) and land surface characteristics such as proximity to inland lakes. However, the two metropolitan areas differ in size, population, structure, and orientation to water bodies. In addition, the sensor networks were established in very different manners. We describe these differences and present lessons learned from the design and ongoing efforts of these two dense networks

Air Sensor Toolbox for Citizen Scientists

EPA Pesticide Factsheets

EPA’s Air Sensor Toolbox provides information and guidance on new low-cost compact technologies for measuring air quality. It provides information to help citizens more effectively and accurately collect air quality data in their community.

Air Sensor Toolbox: Resources and Funding

EPA Pesticide Factsheets

EPA’s Air Sensor Toolbox provides information and guidance on new low-cost compact technologies for measuring air quality. It provides information to help citizens more effectively and accurately collect air quality data in their community.

Small CO2 Sensors Operate at Lower Temperature

NASA Technical Reports Server (NTRS)

Hunter, Gary W.; Xu, Jennifer C.

2009-01-01

Solid-electrolyte-based amperometric sensors for measuring concentrations of CO2 in air are being developed for use in detection of fires, environmental monitoring, and other applications where liquid-based electrochemical cells are problematic. These sensors are small (sizes of the order of a millimeter), are robust, are amenable to batch fabrication at relatively low cost, and exhibit short response times (seconds) and wide detection ranges. A sensor of this type at a previous stage of development included a solid electrolyte of Na3Zr2Si2PO12 deposited mainly between interdigitated Pt electrodes on an alumina substrate, all overcoated with an auxiliary solid electrolyte of (Na2CO3:BaCO3 in a molar ratio of 1:1.7). It was necessary to heat this device to a temperature as high as 600 C to obtain the desired sensitivity and rapid response. Heating sensors increases the power consumption of the sensor system and complicates the use of the sensor in some applications. Thus, decreasing a sensor s power consumption while maintaining its performance is a technical goal of ongoing development.

A high-sensitivity temperature sensor based on Sagnac interferometer employing photonic crystal fiber fully filled with ethanol

NASA Astrophysics Data System (ADS)

Shi, Min; Li, Shuguang; Chen, Hailiang

2018-06-01

A high-sensitivity temperature sensor based on photonic crystal fiber Sagnac interferometer is proposed and studied. All holes of the PCF are filled with ethanol with capillarity. The cladding air holes are uniform arrangements. The two air holes around the core are removed to form new core modes with high birefringence. The sensitivities of the temperature can be up to -8.7657 and 16.8142 nm/°C when temperature rises from 45 to 75 °C and the fiber length is 5.05 cm. And when temperature rises from 10 to 45 °C, the sensitivity can reach -7.848 and 16.655 nm/°C with fiber length 2.11 cm. The performance of the selective-filled and the fully-filled PCF with temperature from 45 to 75 °C and fiber length 5.05 cm are analyzed and compared. The fully filling can better achieve PCF's sensing performance. The simple structure and high sensitivities make the temperature sensor easy to achieve. The temperature sensor with high sensitivities and good linearity has great application value for environmental temperature detecting.

Development of Metal Oxide Nanostructure-based Optical Sensors for Fossil Fuel Derived Gases Measurement at High Temperature

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chen, Kevin P.

2015-02-13

This final technical report details research works performed supported by a Department of Energy grant (DE-FE0003859), which was awarded under the University Coal Research Program administrated by National Energy Technology Laboratory. This research program studied high temperature fiber sensor for harsh environment applications. It developed two fiber optical sensor platform technology including regenerative fiber Bragg grating sensors and distributed fiber optical sensing based on Rayleigh backscattering optical frequency domain reflectometry. Through the studies of chemical and thermal regenerative techniques for fiber Bragg grating (FBG) fabrication, high-temperature stable FBG sensors were successfully developed and fabricated in air-hole microstructured fibers, high-attenuation fibers,more » rare-earth doped fibers, and standard telecommunication fibers. By optimizing the laser processing and thermal annealing procedures, fiber grating sensors with stable performance up to 1100°C have been developed. Using these temperature-stable FBG gratings as sensor platform, fiber optical flow, temperature, pressure, and chemical sensors have been developed to operate at high temperatures up to 800°C. Through the integration of on-fiber functional coating, the use of application-specific air-hole microstructural fiber, and application of active fiber sensing scheme, distributed fiber sensor for temperature, pressure, flow, liquid level, and chemical sensing have been demonstrated with high spatial resolution (1-cm or better) with wide temperature ranges. These include the demonstration of 1) liquid level sensing from 77K to the room temperature, pressure/temperature sensing from the room temperature to 800C and from the 15psi to 2000 psi, and hydrogen concentration measurement from 0.2% to 10% with temperature ranges from the room temperature to 700°C. Optical sensors developed by this program has broken several technical records including flow sensors with the

Fiber optic temperature sensor

NASA Technical Reports Server (NTRS)

Sawatari, Takeo (Inventor); Gaubis, Philip A. (Inventor)

2000-01-01

A fiber optic temperature sensor uses a light source which transmits light through an optical fiber to a sensor head at the opposite end of the optical fiber from the light source. The sensor head has a housing coupled to the end of the optical fiber. A metallic reflective surface is coupled to the housing adjacent the end of the optical fiber to form a gap having a predetermined length between the reflective surface and the optical fiber. A detection system is also coupled to the optical fiber which determines the temperature at the sensor head from an interference pattern of light which is reflected from the reflective surface.

Fiber optic temperature sensor

NASA Technical Reports Server (NTRS)

Sawatari, Takeo (Inventor); Gaubis, Philip A. (Inventor); Mattes, Brenton L. (Inventor); Charnetski, Clark J. (Inventor)

1999-01-01

A fiber optic temperature sensor uses a light source which transmits light through an optical fiber to a sensor head at the opposite end of the optical fiber from the light source. The sensor head has a housing coupled to the end of the optical fiber. A metallic reflective surface is coupled to the housing adjacent the end of the optical fiber to form a gap having a predetermined length between the reflective surface and the optical fiber. A detection system is also coupled to the optical fiber which determines the temperature at the sensor head from an interference pattern of light which is reflected from the reflective surface.

Computer modeling of the sensitivity of a laser water vapor sensor to variations in temperature and air speed

NASA Technical Reports Server (NTRS)

Tucker, George F.

1994-01-01

Currently, there is disagreement among existing methods of determining atmospheric water vapor concentration at dew-points below -40 C. A major source of error is wall effects which result from the necessity of bringing samples into the instruments. All of these instruments also have response times on the order of seconds. NASA Langley is developing a water vapor sensor which utilizes the absorption of the infrared radiation produced by a diode laser to estimate water vapor concentration. The laser beam is directed through an aircraft window to a retroreflector located on an engine. The reflected beam is detected by an infrared detector located near the laser. To maximize signal to noise, derivative signals are analyzed. By measuring the 2f/DC signal and correcting for ambient temperature, atmospheric pressure and air speed (which results in a Doppler shifting of the laser beam), the water vapor concentration can be retrieved. Since this is an in situ measurement there are no wall effects and measurements can be made at a rate of more than 20 per second. This allows small spatial variations of water vapor to be studied. In order to study the sensitivity of the instrument to variations in temperature and air speed, a computer program which generated the 2f, 3f, 4f, DC and 2f/DC signals of the instrument as a function of temperature, pressure and air speed was written. This model was used to determine the effect of errors in measurement of the temperature and air speed on the measured water vapor concentration. Future studies will quantify the effect of pressure measurement errors, which are expected to be very small. As a result of these studied, a retrieval algorithm has been formulated, and will be applied to data taken during the PEM-West atmospheric science field mission. Spectroscopic studies of the water vapor line used by the instrument will be used to refine this algorithm. To prepare for these studies, several lasers have been studied to determine their

Fluorescent temperature sensor

DOEpatents

Baker, Gary A [Los Alamos, NM; Baker, Sheila N [Los Alamos, NM; McCleskey, T Mark [Los Alamos, NM

2009-03-03

The present invention is a fluorescent temperature sensor or optical thermometer. The sensor includes a solution of 1,3-bis(1-pyrenyl)propane within a 1-butyl-1-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide ionic liquid solvent. The 1,3-bis(1-pyrenyl)propane remains unassociated when in the ground state while in solution. When subjected to UV light, an excited state is produced that exists in equilibrium with an excimer. The position of the equilibrium between the two excited states is temperature dependent.

Active thermal isolation for temperature responsive sensors

NASA Technical Reports Server (NTRS)

Martinson, Scott D. (Inventor); Gray, David L. (Inventor); Carraway, Debra L. (Inventor); Reda, Daniel C. (Inventor)

1994-01-01

The detection of flow transition between laminar and turbulent flow and of shear stress or skin friction of airfoils is important in basic research for validation of airfoil theory and design. These values are conventionally measured using hot film nickel sensors deposited on a polyimide substrate. The substrate electrically insulates the sensor and underlying airfoil but is prevented from thermally isolating the sensor by thickness constraints necessary to avoid flow contamination. Proposed heating of the model surface is difficult to control, requires significant energy expenditures, and may alter the basic flow state of the airfoil. A temperature responsive sensor is located in the airflow over the specified surface of a body and is maintained at a constant temperature. An active thermal isolator is located between this temperature responsive sensor and the specific surface of the body. The total thickness of the isolator and sensor avoid any contamination of the flow. The temperature of this isolator is controlled to reduce conductive heat flow from the temperature responsive sensor to the body. This temperature control includes (1) operating the isolator at the same temperature as the constant temperature of the sensor; and (2) establishing a fixed boundary temperature which is either less than or equal to, or slightly greater than the sensor constant temperature. The present invention accordingly thermally isolates a temperature responsive sensor in an energy efficient, controllable manner while avoiding any contamination of the flow.

Rare Earth Optical Temperature Sensor

NASA Technical Reports Server (NTRS)

Chubb, Donald L. (Inventor); Jenkins, Phillip (Inventor)

2004-01-01

A rare earth optical temperature sensor is disclosed for measuring high temperatures. Optical temperature sensors exist that channel emissions from a sensor to a detector using a light pipe. The invention uses a rare earth emitter to transform the sensed thermal energy into a narrow band width optical signal that travels to a detector using a light pipe. An optical bandpass filter at the detector removes any noise signal outside of the band width of the signal from the emitter.

Double air-fuel ratio sensor system having double-skip function

DOE Office of Scientific and Technical Information (OSTI.GOV)

Katsuno, T.

1988-01-26

A method for controlling the air-fuel ratio in an internal combustion engine is described having a catalyst converter for removing pollutants in the exhaust gas thereof, and upstream-side and downstream-side air-fuel ratio sensors disposed upstream and downstream, respectively, of the catalyst converter for detecting a concentration of a specific component in an exhaust gas, comprising the steps of: comparing the output of the upstream-side air-fuel ratio sensor with a first predetermined value; gradually changing a first air-fuel ratio correction amount in accordance with a result of the comparison of the output of the upstream-side air-fuel ratio sensor with the predeterminedmore » value; shifting the first air-fuel ratio correction amount by a first skip amount during a predetermined time period after the result of the comparison of the upstream-side air-fuel ratio sensor is changed; shifting the first air-fuel ratio correction amount by a second skip amount smaller than the first skip amount after the predetermined time period has passed; comparing the output of the downstream-side air-fuel ratio with a second predetermined value, calculating a second air-fuel ratio correction amount in accordance with the comparison result of the output of the downstream-side air-fuel ratio sensor with the second predetermined value; and adjusting the actual air-fuel ratio in accordance with the first and second air-fuel ratio correction amounts; wherein the gradually-changing step comprises the steps of: gradually decreasing the first air-fuel ratio correction amount when the output of the upstream-side air-fuel sensor is on the rich side with respect to the first predetermined value; and gradually increasing the first air-fuel ratio correction amount when the output of the upstream-side air-fuel sensor is on the lean side with respect to the first predetermined value.« less

Air Sensor Guidebook | Science Inventory | US EPA

EPA Pesticide Factsheets

This Air Sensor Guidebook has been developed by the U.S. EPA to assist those interested in potentially using lower cost air quality sensor technologies for air quality measurements. Its development was in direct response to a request for such a document following a recent scientific conference (Apps and Sensors for Air Pollution-2012). Low cost air quality sensors ($100-$2500) are now commercially available in a wide variety of designs and capabilities. This is an emerging technology area and one that is quickly evolving. Even so, their availability has resulted in questions from many as to how they might be used appropriately. This document attempts to provide useful information concerning some of those questions. The National Exposure Research Laboratory’s (NERL’s) Human Exposure and Atmospheric Sciences Division (HEASD) conducts research in support of EPA’s mission to protect human health and the environment. HEASD’s research program supports Goal 1 (Clean Air) and Goal 4 (Healthy People) of EPA’s strategic plan. More specifically, our division conducts research to characterize the movement of pollutants from the source to contact with humans. Our multidisciplinary research program produces Methods, Measurements, and Models to identify relationships between and characterize processes that link source emissions, environmental concentrations, human exposures, and target-tissue dose. The impact of these tools is improved regulatory programs and pol

Active Temperature Compensation Using a High-Temperature, Fiber Optic, Hybrid Pressure and Temperature Sensor

NASA Astrophysics Data System (ADS)

Fielder, Robert S.; Palmer, Matthew E.; Davis, Matthew A.; Engelbrecht, Gordon P.

2006-01-01

Luna Innovations has developed a novel, fiber optic, hybrid pressure-temperature sensor system for extremely high-temperature environments that is capable of reliable operation up to 1050 °C. This system is based on the extremely high-temperature fiber optic sensors already demonstrated during previous work. The novelty of the sensors presented here lies in the fact that pressure and temperature are measured simultaneously with a single fiber and a single transducer. This hybrid approach will enable highly accurate active temperature compensation and sensor self-diagnostics not possible with other platforms. Hybrid pressure and temperature sensors were calibrated by varying both pressure and temperature. Implementing active temperature compensation resulted in a ten-fold reduction in the temperature-dependence of the pressure measurement. Sensors were tested for operability in a relatively high neutron dose environment up to 6.9×1017 n/cm2. In addition to harsh environment survivability, fiber optic sensors offer a number of intrinsic advantages for space nuclear power applications including extremely low mass, immunity to electromagnetic interference, self diagnostics / prognostics, and smart sensor capability. Deploying fiber optic sensors on future space exploration missions would provide a substantial improvement in spacecraft instrumentation. Additional development is needed, however, before these advantages can be realized. This paper will highlight recent demonstrations of fiber optic sensors in environments relevant to space nuclear applications. Successes and lessons learned will be highlighted. Additionally, development needs will be covered which will suggest a framework for a coherent plan to continue work in this area.

Universal sensor based on the spectroscopy of glow discharge for the detection of traces of atoms or molecules in air

NASA Astrophysics Data System (ADS)

Atutov, S. N.; Galeyev, A. E.; Plekhanov, A. I.; Yakovlev, A. V.

2018-03-01

A sensitive and versatile sensor for the detection of traces of atoms or molecules in air based on the emission spectroscopy of glow discharge in air has been developed and studied. The advantages of this sensor compared to other well-known methods are that it renders the use of ultrahigh vacuum or cryogenic temperatures superfluous. The sensor is insensitive to the presence of water vapor (for example, in exhaled air) because of the absence of strong water lines in the visible spectral range. It has a high spectral selectivity limited only by Doppler broadening of the emission lines. The high selectivity of the sensor combined with a wide spectral range allows the detection of many toxic impurities, which can be present in air. Moreover, the spectral range used covers almost all biomarkers in exhaled air, making the proposed sensor extremely interesting for medical applications. To our knowledge, the proposed method is the first based on a glow discharge in air.

Effects of open-air temperature on air temperature inside biological safety cabinet.

PubMed

Umemura, Masayuki; Shigeno, Katsuro; Yamamura, Keiko; Osada, Takashi; Soda, Midori; Yamada, Kiyofumi; Ando, Yuichi; Wakiya, Yoshifumi

2011-02-14

In Japan, biological safety cabinets (BSCs) are normally used by medical staff while handling antineoplastic agents. We have also set up a class II B2 BSC at the Division of Chemotherapy for Outpatients. The air temperature inside this BSC, however, decreases in winter. We assumed that this decrease is caused by the intake of open-air. Therefore, we investigated the effects of low open-air temperature on the BSC temperature and the time of admixtures of antineoplastic agents. The studies were conducted from January 1 to March 31, 2008. The outdoor air temperature was measured in the shade near the intake nozzle of the BSC and was compared with the BSC temperature. The correlation between the outdoor air temperature and the BSC temperature, the dissolution time of cyclophosphamide (CPA) and gemcitabine (GEM), and accurate weight measurement of epirubicin (EPI) solution were investigated for low and normal BSC temperatures. The BSC temperature was correlated with the open-air temperature for open-air temperatures of 5-20°C (p < 0.0001). The dissolution of CPA and GEM at these temperatures was significantly delayed as compared to that at 25°C (p < 0.01 and p < 0.0001, respectively). The weight measurement of EPI solution using a syringe method lacks accuracy because of its high coefficient of viscosity at low temperatures (p < 0.01). These results suggest that the BSC temperature decreases below room temperature in winter when air is drawn from outdoors. We showed that the BSC temperature affects the dissolution rate of antineoplastic agents. Further, we suggested that the BSC temperature drop might delay the affair of the admixtures of antineoplastic agents and increase the waiting time of outpatients for chemotherapy.

Diode laser-based air mass flux sensor for subsonic aeropropulsion inlets

NASA Astrophysics Data System (ADS)

Miller, Michael F.; Kessler, William J.; Allen, Mark G.

1996-08-01

An optical air mass flux sensor based on a compact, room-temperature diode laser in a fiber-coupled delivery system has been tested on a full-scale gas turbine engine. The sensor is based on simultaneous measurements of O 2 density and Doppler-shifted velocity along a line of sight across the inlet duct. Extensive tests spanning engine power levels from idle to full afterburner demonstrate accuracy and precision of the order of 1 2 of full scale in density, velocity, and mass flux. The precision-limited velocity at atmospheric pressure was as low as 40 cm s. Multiple data-reduction procedures are quantitatively compared to suggest optimal strategies for flight sensor packages.

A smart indoor air quality sensor network

NASA Astrophysics Data System (ADS)

Wen, Jin

2006-03-01

The indoor air quality (IAQ) has an important impact on public health. Currently, the indoor air pollution, caused by gas, particle, and bio-aerosol pollutants, is considered as the top five environmental risks to public health and has an estimated cost of $2 billion/year due to medical cost and lost productivity. Furthermore, current buildings are especially vulnerable for chemical and biological warfare (CBW) agent contamination because the central air conditioning and ventilation system serve as a nature carrier to spread the released agent from one location to the whole indoor environment within a short time period. To assure the IAQ and safety for either new or existing buildings, real time comprehensive IAQ and CBW measurements are needed. With the development of new sensing technologies, economic and reliable comprehensive IAQ and CBW sensors become promising. However, few studies exist that examine the design and evaluation issues related to IAQ and CBW sensor network. In this paper, relevant research areas including IAQ and CBW sensor development, demand control ventilation, indoor CBW sensor system design, and sensor system design for other areas such as water system protection, fault detection and diagnosis, are reviewed and summarized. Potential research opportunities for IAQ and CBW sensor system design and evaluation are discussed.

Carbon nanotube temperature and pressure sensors

DOEpatents

Ivanov, Ilia N.; Geohegan, David B.

2016-11-15

The present invention, in one embodiment, provides a method of measuring pressure or temperature using a sensor including a sensor element composed of a plurality of carbon nanotubes. In one example, the resistance of the plurality of carbon nanotubes is measured in response to the application of temperature or pressure. The changes in resistance are then recorded and correlated to temperature or pressure. In one embodiment, the present invention provides for independent measurement of pressure or temperature using the sensors disclosed herein.

Carbon nanotube temperature and pressure sensors

DOEpatents

Ivanov, Ilia N.; Geohegan, David B.

2016-12-13

The present invention, in one embodiment, provides a method of measuring pressure or temperature using a sensor including a sensor element composed of a plurality of carbon nanotubes. In one example, the resistance of the plurality of carbon nanotubes is measured in response to the application of temperature or pressure. The changes in resistance are then recorded and correlated to temperature or pressure. In one embodiment, the present invention provides for independent measurement of pressure or temperature using the sensors disclosed herein.

Carbon nanotube temperature and pressure sensors

DOEpatents

Ivanov, Ilia N; Geohegan, David Bruce

2013-10-29

The present invention, in one embodiment, provides a method of measuring pressure or temperature using a sensor including a sensor element composed of a plurality of carbon nanotubes. In one example, the resistance of the plurality of carbon nanotubes is measured in response to the application of temperature or pressure. The changes in resistance are then recorded and correlated to temperature or pressure. In one embodiment, the present invention provides for independent measurement of pressure or temperature using the sensors disclosed herein.

Carbon nanotube temperature and pressure sensors

DOEpatents

Ivanov, Ilia N.; Geohegan, David B.

2016-10-25

The present invention, in one embodiment, provides a method of measuring pressure or temperature using a sensor including a sensor element composed of a plurality of carbon nanotubes. In one example, the resistance of the plurality of carbon nanotubes is measured in response to the application of temperature or pressure. The changes in resistance are then recorded and correlated to temperature or pressure. In one embodiment, the present invention provides for independent measurement of pressure or temperature using the sensors disclosed herein.

Carbon nanotube temperature and pressure sensors

DOEpatents

Ivanov, Ilia N.; Geohegan, David B.

2017-09-12

The present invention, in one embodiment, provides a method of measuring pressure or temperature using a sensor including a sensor element composed of a plurality of carbon nanotubes. In one example, the resistance of the plurality of carbon nanotubes is measured in response to the application of temperature or pressure. The changes in resistance are then recorded and correlated to temperature or pressure. In one embodiment, the present invention provides for independent measurement of pressure or temperature using the sensors disclosed herein.

Wireless Sensor Network Applications for the Combat Air Forces

DTIC Science & Technology

2006-06-13

WIRELESS SENSOR NETWORK APPLICATIONS FOR THE COMBAT AIR FORCES GRADUATE RESEARCH PROJECT...Government. AFIT/IC4/ENG/06-05 WIRELESS SENSOR NETWORK APPLICATIONS FOR THE COMBAT AIR FORCES GRADUATE RESEARCH PROJECT Presented to the...Major, USAF June 2006 APPROVED FOR PUBLIC RELEASE; DISTRIBUTION UNLIMITED AFIT/IC4/ENG/06-05 WIRELESS SENSOR NETWORK APPLICATIONS

Air-Microfluidics: Creating Small, Low-cost, Portable Air Quality Sensors

EPA Science Inventory

Air-microfluidics shows great promise in dramatically reducing the size, cost, and power requirements of future air quality sensors without compromising their accuracy. Microfabrication provides a suite of relatively new tools for the development of micro electro mechanical syste...

Modulated-splitting-ratio fiber-optic temperature sensor

NASA Technical Reports Server (NTRS)

Beheim, Glenn; Anthan, Donald J.; Rys, John R.; Fritsch, Klaus; Ruppe, Walter A.

1988-01-01

A fiber-optic temperature sensor is described, which uses a small silicon beamsplitter whose splitting ratio varies as a function of temperature. A four-beam technique is used to measure the sensor's temperature-indicating splitting ratio. This referencing method provides a measurement that is largely independent of the transmission properties of the sensor's optical fiber link. A significant advantage of this sensor, relative to other fiber-optic sensors, is its high stability, which permits the fiber-optic components to be readily substituted, thereby simplifying the sensor's installation and maintenance.

Variability of Winter Air Temperature in Mid-Latitude Europe

NASA Technical Reports Server (NTRS)

Otterman, J.; Ardizzone, J.; Atlas, R.; Bungato, D.; Cierniewski, J.; Jusem, J. C.; Przybylak, R.; Schubert, S.; Starr, D.; Walczewski, J.

2002-01-01

The aim of this paper is to report extreme winter/early-spring air temperature (hereinafter temperature) anomalies in mid-latitude Europe, and to discuss the underlying forcing to these interannual fluctuations. Warm advection from the North Atlantic in late winter controls the surface-air temperature, as indicated by the substantial correlation between the speed of the surface southwesterlies over the eastern North Atlantic (quantified by a specific Index Ina) and the 2-meter level air temperatures (hereinafter Ts) over Europe, 45-60 deg N, in winter. In mid-March and subsequently, the correlation drops drastically (quite often it is negative). This change in the relationship between Ts and Ina marks a transition in the control of the surface-air temperature: absorption of insolation replaces the warm advection as the dominant control. This forcing by maritime-air advection in winter was demonstrated in a previous publication, and is re-examined here in conjunction with extreme fluctuations of temperatures in Europe. We analyze here the interannual variability at its extreme by comparing warm-winter/early-spring of 1989/90 with the opposite scenario in 1995/96. For these two December-to-March periods the differences in the monthly mean temperature in Warsaw and Torun, Poland, range above 10 C. Short-term (shorter than a month) fluctuations of the temperature are likewise very strong. We conduct pentad-by-pentad analysis of the surface-maximum air temperature (hereinafter Tmax), in a selected location, examining the dependence on Ina. The increased cloudiness and higher amounts of total precipitable water, corollary effects to the warm low-level advection. in the 1989/90 winter, enhance the positive temperature anomalies. The analysis of the ocean surface winds is based on the Special Sensor Microwave/Imager (SSM/I) dataset; ascent rates, and over land wind data are from the European Centre for Medium-Range Weather Forecasts (ECMWF); maps of 2-m temperature, cloud

CityAir app: Mapping air-quality perception using people as sensors

NASA Astrophysics Data System (ADS)

Castell, Nuria; Fredriksen, Mirjam; Cole-Hunter, Thomas; Robinson, Johanna; Keune, Hans; Nieuwenhuijsen, Mark; Bartonova, Alena

2016-04-01

Outdoor air pollution is a major environmental health problem affecting all people in developed and developing countries alike. Ambient (outdoor) air pollution in both cities and rural areas was estimated to cause 3.7 million premature deaths worldwide in 2012. In modern society, people are expending an increasing amount of time in polluted urban environments, thus increasing their exposure and associated health responses. Some cities provide information about air pollution levels to their citizens using air quality monitoring networks. However, due to their high cost and maintenance, the density of the monitoring networks is very low and not capable to capture the high temporal and spatial variability of air pollution. Thus, the citizen lacks a specific answer to the question of "how the air quality is in our surroundings". In the framework of the EU-funded CITI-SENSE project the innovative concept of People as Sensors is being applied to the field of outdoor air pollution. This is being done in eight European cities, including Barcelona, Belgrade, Edinburgh, Haifa, Ljubljana, Oslo, Ostrava and Vienna. People as Sensors defines a measurement model, in which measurements are not only taken by hardware sensors, but in which also humans can contribute with their individual "measurements" such as their subjective perception of air quality and other personal observations. In order to collect the personal observations a mobile app, CityAir, has been developed. CityAir allows citizens to rate the air quality in their surroundings with colour at their current location: green if air quality is very good, yellow if air quality is good, orange if air quality is poor and red if air quality is very poor. The users have also the possibility of indicating the source of pollution (i.e. traffic, industry, wood burning) and writing a comment. The information is on-line and accessible for other app users, thus contributing to create an air-quality map based on citizens' perception

Acoustic Sensors for Air and Surface Navigation Applications

PubMed Central

Kapoor, Rohan; Ramasamy, Subramanian; Schyndel, Ron Van

2018-01-01

This paper presents the state-of-the-art and reviews the state-of-research of acoustic sensors used for a variety of navigation and guidance applications on air and surface vehicles. In particular, this paper focuses on echolocation, which is widely utilized in nature by certain mammals (e.g., cetaceans and bats). Although acoustic sensors have been extensively adopted in various engineering applications, their use in navigation and guidance systems is yet to be fully exploited. This technology has clear potential for applications in air and surface navigation/guidance for intelligent transport systems (ITS), especially considering air and surface operations indoors and in other environments where satellite positioning is not available. Propagation of sound in the atmosphere is discussed in detail, with all potential attenuation sources taken into account. The errors introduced in echolocation measurements due to Doppler, multipath and atmospheric effects are discussed, and an uncertainty analysis method is presented for ranging error budget prediction in acoustic navigation applications. Considering the design challenges associated with monostatic and multi-static sensor implementations and looking at the performance predictions for different possible configurations, acoustic sensors show clear promises in navigation, proximity sensing, as well as obstacle detection and tracking. The integration of acoustic sensors in multi-sensor navigation systems is also considered towards the end of the paper and a low Size, Weight and Power, and Cost (SWaP-C) sensor integration architecture is presented for possible introduction in air and surface navigation systems. PMID:29414894

Development of Metal-Ceramic Coaxial Cable Fabry-Pérot Interferometric Sensors for High Temperature Monitoring.

PubMed

Trontz, Adam; Cheng, Baokai; Zeng, Shixuan; Xiao, Hai; Dong, Junhang

2015-09-25

Metal-ceramic coaxial cable Fabry-Pérot interferometric (MCCC-FPI) sensors have been developed using a stainless steel tube and a stainless steel wire as the outer and inner conductors, respectively; a tubular α-alumina insulator; and a pair of air gaps created in the insulator along the cable to serve as weak reflectors for the transmitting microwave (MW) signal. The MCCC-FPI sensors have been demonstrated for high temperature measurements using MW signals in a frequency range of 2-8 GHz. The temperature measurement is achieved by monitoring the frequency shift (Δƒ) of the MW interferogram reflected from the pair of weak reflectors. The MW sensor exhibited excellent linear dependence of Δƒ on temperature; small measurement deviations (±2.7%); and fast response in a tested range of 200-500 °C. The MCCC has the potential for further developing multipoint FPI sensors in a single-cable to achieve in situ and continuous measurement of spatially distributed temperature in harsh environments.

Fiber optic, Fabry-Perot high temperature sensor

NASA Technical Reports Server (NTRS)

James, K.; Quick, B.

1984-01-01

A digital, fiber optic temperature sensor using a variable Fabry-Perot cavity as the sensor element was analyzed, designed, fabricated, and tested. The fiber transmitted cavity reflection spectra is dispersed then converted from an optical signal to electrical information by a charged coupled device (CCD). A microprocessor-based color demodulation system converts the wavelength information to temperature. This general sensor concept not only utilizes an all-optical means of parameter sensing and transmitting, but also exploits microprocessor technology for automated control, calibration, and enhanced performance. The complete temperature sensor system was evaluated in the laboratory. Results show that the Fabry-Perot temperature sensor has good resolution (0.5% of full seale), high accuracy, and potential high temperature ( 1000 C) applications.

Advanced high temperature heat flux sensors

NASA Technical Reports Server (NTRS)

Atkinson, W.; Hobart, H. F.; Strange, R. R.

1983-01-01

To fully characterize advanced high temperature heat flux sensors, calibration and testing is required at full engine temperature. This required the development of unique high temperature heat flux test facilities. These facilities were developed, are in place, and are being used for advanced heat flux sensor development.

Temperature-Centric Evaluation of Sensor Transients

NASA Astrophysics Data System (ADS)

Ayhan, Tuba; Muezzinoglu, Kerem; Vergara, Alexander; Yalcin, Mustak

2011-09-01

Controllable sensing conditions provide the means for diversifying sensor response and achieving better selectivity. Modulating the sensing layer temperature of metal-oxide sensors is a popular method for multiplexing the limited number of sensing elements that can be employed in a practical array. Time limitations in many applications, however, cannot tolerate an ad-hoc, one-size-fits-all modulation pattern. When the response pattern is itself non-stationary, as in the transient phase, a temperature program also becomes infeasible. We consider the problem of determining and tuning into a fixed optimum temperature in a sensor array. For this purpose, we present an empirical analysis of the temperature's role on the performance of a metal-oxide gas sensor array in the identification of odorants along the response transient. We show that the optimal temperature in this sense depends heavily on the selection of (i) the set of candidate analytes, (ii) the time-window of the analysis, (iii) the feature extracted from the sensor response, and (iv) the computational identification method used.

Understanding social and behavioral drivers and impacts of air quality sensor use.

PubMed

Hubbell, Bryan J; Kaufman, Amanda; Rivers, Louie; Schulte, Kayla; Hagler, Gayle; Clougherty, Jane; Cascio, Wayne; Costa, Dan

2018-04-15

Lower-cost air quality sensors (hundreds to thousands of dollars) are now available to individuals and communities. This technology is undergoing a rapid and fragmented evolution, resulting in sensors that have uncertain data quality, measure different air pollutants and possess a variety of design attributes. Why and how individuals and communities choose to use sensors is arguably influenced by social context. For example, community experiences with environmental exposures and health effects and related interactions with industry and government can affect trust in traditional air quality monitoring. To date, little social science research has been conducted to evaluate why or how sensors, and sensor data, are used by individuals and communities, or how the introduction of sensors changes the relationship between communities and air quality managers. This commentary uses a risk governance/responsible innovation framework to identify opportunities for interdisciplinary research that brings together social scientists with air quality researchers involved in developing, testing, and deploying sensors in communities. Potential areas for social science research include communities of sensor users; drivers for use of sensors and sensor data; behavioral, socio-political, and ethical implications of introducing sensors into communities; assessing methods for communicating sensor data; and harnessing crowdsourcing capabilities to analyze sensor data. Social sciences can enhance understanding of perceptions, attitudes, behaviors, and other human factors that drive levels of engagement with and trust in different types of air quality data. New transdisciplinary research bridging social sciences, natural sciences, engineering, and design fields of study, and involving citizen scientists working with professionals from a variety of backgrounds, can increase our understanding of air sensor technology use and its impacts on air quality and public health. Published by Elsevier B.V.

Micro sensor node for air pollutant monitoring: hardware and software issues.

PubMed

Choi, Sukwon; Kim, Nakyoung; Cha, Hojung; Ha, Rhan

2009-01-01

Wireless sensor networks equipped with various gas sensors have been actively used for air quality monitoring. Previous studies have typically explored system issues that include middleware or networking performance, but most research has barely considered the details of the hardware and software of the sensor node itself. In this paper, we focus on the design and implementation of a sensor board for air pollutant monitoring applications. Several hardware and software issues are discussed to explore the possibilities of a practical WSN-based air pollution monitoring system. Through extensive experiments and evaluation, we have determined the various characteristics of the gas sensors and their practical implications for air pollutant monitoring systems.

Ultrahigh Temperature Capacitive Pressure Sensor

NASA Technical Reports Server (NTRS)

Harsh, Kevin

2014-01-01

Robust, miniaturized sensing systems are needed to improve performance, increase efficiency, and track system health status and failure modes of advanced propulsion systems. Because microsensors must operate in extremely harsh environments, there are many technical challenges involved in developing reliable systems. In addition to high temperatures and pressures, sensing systems are exposed to oxidation, corrosion, thermal shock, fatigue, fouling, and abrasive wear. In these harsh conditions, sensors must be able to withstand high flow rates, vibration, jet fuel, and exhaust. In order for existing and future aeropropulsion turbine engines to improve safety and reduce cost and emissions while controlling engine instabilities, more accurate and complete sensor information is necessary. High-temperature (300 to 1,350 C) capacitive pressure sensors are of particular interest due to their high measurement bandwidth and inherent suitability for wireless readout schemes. The objective of this project is to develop a capacitive pressure sensor based on silicon carbon nitride (SiCN), a new class of high-temperature ceramic materials, which possesses excellent mechanical and electric properties at temperatures up to 1,600 C.

Modeling and testing of fast response, fiber-optic temperature sensors

NASA Astrophysics Data System (ADS)

Tonks, Michael James

have a faster response time compared to the thermocouple. When the sensors were extended 12.7 cm into the flow, the fiber-optic sensors recorded a temperature change of 143 K compared to 38 K recorded by the thermocouple during the 0.5 millisecond test. This corresponds to 22% of the change of total temperature in the air recorded by the fiber-optic sensor and only 6% recorded by the thermocouple. Put another way, the fiber-optic sensor experience a rate of temperature change equal to 2.9x105 K/s and the thermocouple changed at a rate of 0.79x105 K/s. The data recorded from the fiber-optic sensor also contained much less noise than the thermocouple data. An unsteady finite element thermal model was created using ANSYS to predict the temperature response of the sensor. Test cases with known analytical solutions were used to verify the ANSYS modeling procedures. The shock tube flow environment was also modeled with Fluent, a commercially available CFD code. Fluent was used to determine the heat transfer between the shock tube flow and the sensor. The convection film coefficient for the flow was predicted by Fluent to be 27,150 W/m2K for the front of the wafer and 13,385 W/m2K for the side. The Fluent results were used with the ANSYS model to predict the response of the fiber-optic sensor when exposed to the shock tube flow. The results from the Fluent/ANSYS model were compared to the fiber-optic measurements taken in the shock tube. It was seen that the heat flux to the sensor was slightly over-predicted by the model, and the heat losses from the wafer were also over-predicted. Since the prediction fell within the uncertainty of the measurement, it was found to be in good agreement with the measured values. (Abstract shortened by UMI.)

Single Walled Carbon Nanotube Based Air Pocket Encapsulated Ultraviolet Sensor.

PubMed

Kim, Sun Jin; Han, Jin-Woo; Kim, Beomseok; Meyyappan, M

2017-11-22

Carbon nanotube (CNT) is a promising candidate as a sensor material for the sensitive detection of gases/vapors, biomarkers, and even some radiation, as all these external variables affect the resistance and other properties of nanotubes, which forms the basis for sensing. Ultraviolet (UV) radiation does not impact the nanotube properties given the substantial mismatch of bandgaps and therefore, CNTs have never been considered for UV sensing, unlike the popular ZnO and other oxide nanwires. It is well-known that UV assists the adsorption/desorption characteristics of oxygen on carbon nanotubes, which changes the nanotube resistance. Here, we demonstrate a novel sensor structure encapsulated with an air pocket, where the confined air is responsible for the UV sensing mechanism and assures sensor stability and repeatability over time. In addition to the protection from any contamination, the air pocket encapsulated sensor offers negligible baseline drift and fast recovery compared to previously reported sensors. The air pocket isolated from the outside environment can act as a stationary oxygen reservoir, resulting in consistent sensor characteristics. Furthermore, this sensor can be used even in liquid environments.

Analysis of building envelope insulation performance utilizing integrated temperature and humidity sensors.

PubMed

Hung, San-Shan; Chang, Chih-Yuan; Hsu, Cheng-Jui; Chen, Shih-Wei

2012-01-01

A major cause of high energy consumption for air conditioning in indoor spaces is the thermal storage characteristics of a building's envelope concrete material; therefore, the physiological signals (temperature and humidity) within concrete structures are an important reference for building energy management. The current approach to measuring temperature and humidity within concrete structures (i.e., thermocouples and fiber optics) is limited by problems of wiring requirements, discontinuous monitoring, and high costs. This study uses radio frequency integrated circuits (RFIC) combined with temperature and humidity sensors (T/H sensors) for the design of a smart temperature and humidity information material (STHIM) that automatically, regularly, and continuously converts temperature and humidity signals within concrete and transmits them by radio frequency (RF) to the Building Physiology Information System (BPIS). This provides a new approach to measurement that incorporates direct measurement, wireless communication, and real-time continuous monitoring to assist building designers and users in making energy management decisions and judgments.

Analysis of Building Envelope Insulation Performance Utilizing Integrated Temperature and Humidity Sensors

PubMed Central

Hung, San-Shan; Chang, Chih-Yuan; Hsu, Cheng-Jui; Chen, Shih-Wei

2012-01-01

A major cause of high energy consumption for air conditioning in indoor spaces is the thermal storage characteristics of a building's envelope concrete material; therefore, the physiological signals (temperature and humidity) within concrete structures are an important reference for building energy management. The current approach to measuring temperature and humidity within concrete structures (i.e., thermocouples and fiber optics) is limited by problems of wiring requirements, discontinuous monitoring, and high costs. This study uses radio frequency integrated circuits (RFIC) combined with temperature and humidity sensors (T/H sensors) for the design of a smart temperature and humidity information material (STHIM) that automatically, regularly, and continuously converts temperature and humidity signals within concrete and transmits them by radio frequency (RF) to the Building Physiology Information System (BPIS). This provides a new approach to measurement that incorporates direct measurement, wireless communication, and real-time continuous monitoring to assist building designers and users in making energy management decisions and judgments. PMID:23012529

Crowdsourcing urban air temperatures from smartphone battery temperatures

NASA Astrophysics Data System (ADS)

Overeem, Aart; Robinson, James C. R.; Leijnse, Hidde; Steeneveld, Gert-Jan; Horn, Berthold K. P.; Uijlenhoet, Remko

2014-05-01

Accurate air temperature observations in urban areas are important for meteorology and energy demand planning. They are indispensable to study the urban heat island effect and the adverse effects of high temperatures on human health. However, the availability of temperature observations in cities is often limited. Here we show that relatively accurate air temperature information for the urban canopy layer can be obtained from an alternative, nowadays omnipresent source: smartphones. In this study, battery temperatures were collected by an Android application for smartphones. It has been shown that a straightforward heat transfer model can be employed to estimate daily mean air temperatures from smartphone battery temperatures for eight major cities around the world. The results demonstrate the enormous potential of this crowdsourcing application for real-time temperature monitoring in densely populated areas. Battery temperature data were collected by users of an Android application for cell phones (opensignal.com). The application automatically sends battery temperature data to a server for storage. In this study, battery temperatures are averaged in space and time to obtain daily averaged battery temperatures for each city separately. A regression model, which can be related to a physical model, is employed to retrieve daily air temperatures from battery temperatures. The model is calibrated with observed air temperatures from a meteorological station of an airport located in or near the city. Time series of air temperatures are obtained for each city for a period of several months, where 50% of the data is for independent verification. The methodology has been applied to Buenos Aires, London, Los Angeles, Paris, Mexico City, Moscow, Rome, and Sao Paulo. The evolution of the retrieved air temperatures often correspond well with the observed ones. The mean absolute error of daily air temperatures is less than 2 degrees Celsius, and the bias is within 1 degree

Use of electrochemical sensors for measurement of air pollution: correcting interference response and validating measurements

NASA Astrophysics Data System (ADS)

Cross, Eben S.; Williams, Leah R.; Lewis, David K.; Magoon, Gregory R.; Onasch, Timothy B.; Kaminsky, Michael L.; Worsnop, Douglas R.; Jayne, John T.

2017-09-01

The environments in which we live, work, and play are subject to enormous variability in air pollutant concentrations. To adequately characterize air quality (AQ), measurements must be fast (real time), scalable, and reliable (with known accuracy, precision, and stability over time). Lower-cost air-quality-sensor technologies offer new opportunities for fast and distributed measurements, but a persistent characterization gap remains when it comes to evaluating sensor performance under realistic environmental sampling conditions. This limits our ability to inform the public about pollution sources and inspire policy makers to address environmental justice issues related to air quality. In this paper, initial results obtained with a recently developed lower-cost air-quality-sensor system are reported. In this project, data were acquired with the ARISense integrated sensor package over a 4.5-month time interval during which the sensor system was co-located with a state-operated (Massachusetts, USA) air quality monitoring station equipped with reference instrumentation measuring the same pollutant species. This paper focuses on validating electrochemical (EC) sensor measurements of CO, NO, NO2, and O3 at an urban neighborhood site with pollutant concentration ranges (parts per billion by volume, ppb; 5 min averages, ±1σ): [CO] = 231 ± 116 ppb (spanning 84-1706 ppb), [NO] = 6.1 ± 11.5 ppb (spanning 0-209 ppb), [NO2] = 11.7 ± 8.3 ppb (spanning 0-71 ppb), and [O3] = 23.2 ± 12.5 ppb (spanning 0-99 ppb). Through the use of high-dimensional model representation (HDMR), we show that interference effects derived from the variable ambient gas concentration mix and changing environmental conditions over three seasons (sensor flow-cell temperature = 23.4 ± 8.5 °C, spanning 4.1 to 45.2 °C; and relative humidity = 50.1 ± 15.3 %, spanning 9.8-79.9 %) can be effectively modeled for the Alphasense CO-B4, NO-B4, NO2-B43F, and Ox-B421 sensors, yielding (5 min average) root

Passive Resistor Temperature Compensation for a High-Temperature Piezoresistive Pressure Sensor.

PubMed

Yao, Zong; Liang, Ting; Jia, Pinggang; Hong, Yingping; Qi, Lei; Lei, Cheng; Zhang, Bin; Li, Wangwang; Zhang, Diya; Xiong, Jijun

2016-07-22

The main limitation of high-temperature piezoresistive pressure sensors is the variation of output voltage with operating temperature, which seriously reduces their measurement accuracy. This paper presents a passive resistor temperature compensation technique whose parameters are calculated using differential equations. Unlike traditional experiential arithmetic, the differential equations are independent of the parameter deviation among the piezoresistors of the microelectromechanical pressure sensor and the residual stress caused by the fabrication process or a mismatch in the thermal expansion coefficients. The differential equations are solved using calibration data from uncompensated high-temperature piezoresistive pressure sensors. Tests conducted on the calibrated equipment at various temperatures and pressures show that the passive resistor temperature compensation produces a remarkable effect. Additionally, a high-temperature signal-conditioning circuit is used to improve the output sensitivity of the sensor, which can be reduced by the temperature compensation. Compared to traditional experiential arithmetic, the proposed passive resistor temperature compensation technique exhibits less temperature drift and is expected to be highly applicable for pressure measurements in harsh environments with large temperature variations.

Passive Resistor Temperature Compensation for a High-Temperature Piezoresistive Pressure Sensor

PubMed Central

Yao, Zong; Liang, Ting; Jia, Pinggang; Hong, Yingping; Qi, Lei; Lei, Cheng; Zhang, Bin; Li, Wangwang; Zhang, Diya; Xiong, Jijun

2016-01-01

The main limitation of high-temperature piezoresistive pressure sensors is the variation of output voltage with operating temperature, which seriously reduces their measurement accuracy. This paper presents a passive resistor temperature compensation technique whose parameters are calculated using differential equations. Unlike traditional experiential arithmetic, the differential equations are independent of the parameter deviation among the piezoresistors of the microelectromechanical pressure sensor and the residual stress caused by the fabrication process or a mismatch in the thermal expansion coefficients. The differential equations are solved using calibration data from uncompensated high-temperature piezoresistive pressure sensors. Tests conducted on the calibrated equipment at various temperatures and pressures show that the passive resistor temperature compensation produces a remarkable effect. Additionally, a high-temperature signal-conditioning circuit is used to improve the output sensitivity of the sensor, which can be reduced by the temperature compensation. Compared to traditional experiential arithmetic, the proposed passive resistor temperature compensation technique exhibits less temperature drift and is expected to be highly applicable for pressure measurements in harsh environments with large temperature variations. PMID:27455271

Ice Surface Temperature Variability in the Polar Regions and the Relationships to 2 Meter Air Temperatures

NASA Astrophysics Data System (ADS)

Hoyer, J.; Madsen, K. S.; Englyst, P. N.

2017-12-01

Determining the surface and near surface air temperature from models or observations in the Polar Regions is challenging due to the extreme conditions and the lack of in situ observations. The errors in near surface temperature products are typically larger than for other regions of the world, and the potential for using Earth Observations is large. As part of the EU project, EUSTACE, we have developed empirical models for the relationship between the satellite observed skin ice temperatures and 2m air temperatures. We use the Arctic and Antarctic Sea and sea ice Surface Temperatures from thermal Infrared satellite sensors (AASTI) reanalysis to estimate daily surface air temperature over land ice and sea ice for the Arctic and the Antarctic. Large efforts have been put into collecting and quality controlling in situ observations from various data portals and research projects. The reconstruction is independent of numerical weather prediction models and thus provides an important alternative to modelled air temperature estimates. The new surface air temperature data record has been validated against more than 58.000 independent in situ measurements for the four surface types: Arctic sea ice, Greenland ice sheet, Antarctic sea ice and Antarctic ice sheet. The average correlations are 92-97% and average root mean square errors are 3.1-3.6°C for the four surface types. The root mean square error includes the uncertainty of the in-situ measurement, which ranges from 0.5 to 2°C. A comparison with ERA-Interim shows a consistently better performance of the satellite based air temperatures than the ERA-Interim for the Greenland ice sheet, when compared against observations not used in any of the two estimates. This is encouraging and demonstrates the values of these products. In addition, the procedure presented here works on satellite observations that are available in near real time and this opens up for a near real time estimation of the surface air temperature over

Temperature-independent curvature sensor based on tapered photonic crystal fiber interferometer

NASA Astrophysics Data System (ADS)

Ni, Kai; Li, Tao; Hu, Limin; Qian, Wenwen; Zhang, Quanyao; Jin, Shangzhong

2012-11-01

A temperature-independent highly-sensitive curvature sensor by using a tapered-photonic crystal fiber (PCF)-based Mach-Zehnder interferometer (MZI) is proposed and experimentally demonstrated. It is fabricated by sandwiching a tapered-PCF between two standard single mode fibers (SMFs) with the air holes of the PCF in the fusion splicing region being fully collapsed. The tapering of PCF is found to enhance the sensitivity significantly. Large curvature sensitivities of 2.81 dB/m-1 and 8.35 dB/m-1 are achieved in the measurement ranges of 0.36-0.87 m-1 and 0.87-1.34 m-1, respectively, with the resolution of 0.0012 m-1 being guaranteed. The proposed sensor also shows negligible temperature sensitivity less than 0.006 dB/°C.

MEMS Fabry-Perot sensor interrogated by optical system-on-a-chip for simultaneous pressure and temperature sensing.

PubMed

Pang, Cheng; Bae, Hyungdae; Gupta, Ashwani; Bryden, Kenneth; Yu, Miao

2013-09-23

We present a micro-electro-mechanical systems (MEMS) based Fabry-Perot (FP) sensor along with an optical system-on-a-chip (SOC) interrogator for simultaneous pressure and temperature sensing. The sensor employs a simple structure with an air-backed silicon membrane cross-axially bonded to a 45° polished optical fiber. This structure renders two cascaded FP cavities, enabling simultaneous pressure and temperature sensing in close proximity along the optical axis. The optical SOC consists of a broadband source, a MEMS FP tunable filter, a photodetector, and the supporting circuitry, serving as a miniature spectrometer for retrieving the two FP cavity lengths. Within the measured pressure and temperature ranges, experimental results demonstrate that the sensor exhibits a good linear response to external pressure and temperature changes.

High-Temperature Gas Sensor Array (Electronic Nose) Demonstrated

NASA Technical Reports Server (NTRS)

Hunter, Gary W.

2002-01-01

The ability to measure emissions from aeronautic engines and in commercial applications such as automotive emission control and chemical process monitoring is a necessary first step if one is going to actively control those emissions. One single sensor will not give all the information necessary to determine the chemical composition of a high-temperature, harsh environment. Rather, an array of gas sensor arrays--in effect, a high-temperature electronic "nose"--is necessary to characterize the chemical constituents of a diverse, high-temperature environment, such as an emissions stream. The signals produced by this nose could be analyzed to determine the constituents of the emission stream. Although commercial electronic noses for near-room temperature applications exist, they often depend significantly on lower temperature materials or only one sensor type. A separate development effort necessary for a high-temperature electronic nose is being undertaken by the NASA Glenn Research Center, Case Western Reserve University, Ohio State University, and Makel Engineering, Inc. The sensors are specially designed for hightemperature environments. A first-generation high-temperature electronic nose has been demonstrated on a modified automotive engine. This nose sensor array was composed of sensors designed for hightemperature environments fabricated using microelectromechanical-systems- (MEMS-) based technology. The array included a tin-oxide-based sensor doped for nitrogen oxide (NOx) sensitivity, a SiC-based hydrocarbon (CxHy) sensor, and an oxygen sensor (O2). These sensors operate on different principles--resistor, diode, and electrochemical cell, respectively--and each sensor has very different responses to the individual gases in the environment. A picture showing the sensor head for the array is shown in the photograph on the left and the sensors installed in the engine are shown in the photograph on the right. Electronics are interfaced with the sensors for

Thin film temperature sensor

NASA Technical Reports Server (NTRS)

Grant, H. P.; Przybyszewski, J. S.

1980-01-01

Thin film surface temperature sensors were developed. The sensors were made of platinum-platinum/10 percent rhodium thermocouples with associated thin film-to-lead wire connections and sputtered on aluminum oxide coated simulated turbine blades for testing. Tests included exposure to vibration, low velocity hydrocarbon hot gas flow to 1250 K, and furnace calibrations. Thermal electromotive force was typically two percent below standard type S thermocouples. Mean time to failure was 42 hours at a hot gas flow temperature of 1250 K and an average of 15 cycles to room temperature. Failures were mainly due to separation of the platinum thin film from the aluminum oxide surface. Several techniques to improve the adhesion of the platinum are discussed.

Optical temperature sensor using thermochromic semiconductors

DOEpatents

Kronberg, James W.

1998-01-01

An optical temperature measuring device utilizes thermochromic semiconductors which vary in color in response to changes in temperature. The thermochromic material is sealed in a glass matrix which allows the temperature sensor to detect high temperatures without breakdown. Cuprous oxide and cadmium sulfide are among the semiconductor materials which provide the best results. The changes in color may be detected visually using a sensor chip and an accompanying color card.

Distributed temperature sensor testing in liquid sodium

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gerardi, Craig; Bremer, Nathan; Lisowski, Darius

Rayleigh-backscatter-based distributed fiber optic sensors were immersed in sodium to obtain high-resolution liquid-sodium temperature measurements. Distributed temperature sensors (DTSs) functioned well up to 400°C in a liquid sodium environment. The DTSs measured sodium column temperature and the temperature of a complex geometrical pattern that leveraged the flexibility of fiber optics. A single Ø 360 lm OD sensor registered dozens of temperatures along a length of over one meter at 100 Hz. We also demonstrated the capability to use a single DTS to simultaneously detect thermal interfaces (e.g. sodium level) and measure temperature.

Isolating Gas Sensor From Pressure And Temperature Effects

NASA Technical Reports Server (NTRS)

Sprinkle, Danny R.; Chen, Tony T. D.; Chaturvedi, Sushi K.

1994-01-01

Two-stage flow system enables oxygen sensor in system to measure oxygen content of low-pressure, possibly-high-temperature atmosphere in test environment while protecting sensor against possibly high temperature and fluctuations in pressure of atmosphere. Sensor for which flow system designed is zirconium oxide oxygen sensor sampling atmospheres in high-temperature wind tunnels. Also adapted to other gas-analysis instruments that must be isolated from pressure and temperature effects of test environments.

Development of Metal-Ceramic Coaxial Cable Fabry-Pérot Interferometric Sensors for High Temperature Monitoring

PubMed Central

Trontz, Adam; Cheng, Baokai; Zeng, Shixuan; Xiao, Hai; Dong, Junhang

2015-01-01

Metal-ceramic coaxial cable Fabry-Pérot interferometric (MCCC-FPI) sensors have been developed using a stainless steel tube and a stainless steel wire as the outer and inner conductors, respectively; a tubular α-alumina insulator; and a pair of air gaps created in the insulator along the cable to serve as weak reflectors for the transmitting microwave (MW) signal. The MCCC-FPI sensors have been demonstrated for high temperature measurements using MW signals in a frequency range of 2–8 GHz. The temperature measurement is achieved by monitoring the frequency shift (Δƒ) of the MW interferogram reflected from the pair of weak reflectors. The MW sensor exhibited excellent linear dependence of Δƒ on temperature; small measurement deviations (±2.7%); and fast response in a tested range of 200–500 °C. The MCCC has the potential for further developing multipoint FPI sensors in a single-cable to achieve in situ and continuous measurement of spatially distributed temperature in harsh environments. PMID:26404280

Integrated Temperature and Hydrogen Sensors with MEMS Technology

PubMed Central

Jiang, Hongchuan; Huang, Min; Yu, Yibing; Tian, Xiaoyu; Zhang, Wanli; Zhang, Jianfeng; Huang, Yifan; Yu, Kun

2017-01-01

In this work, a PdNi thin film hydrogen gas sensor with integrated Pt thin film temperature sensor was designed and fabricated using the micro-electro-mechanical system (MEMS) process. The integrated sensors consist of two resistors: the former, based on Pt film, is used as a temperature sensor, while the latter had the function of hydrogen sensing and is based on PdNi alloy film. The temperature coefficient of resistance (TCR) in both devices was measured and the output response of the PdNi film hydrogen sensor was calibrated based on the temperature acquired by the Pt temperature sensor. The SiN layer was deposited on top of Pt film to inhibit the hydrogen diffusion and reduce consequent disturbance on temperature measurement. The TCR of the PdNi film and the Pt film was about 0.00122/K and 0.00217/K, respectively. The performances of the PdNi film hydrogen sensor were investigated with hydrogen concentrations from 0.3% to 3% on different temperatures from 294.7 to 302.2 K. With the measured temperature of the Pt resistor and the TCR of the PdNi film, the impact of the temperature on the performances of the PdNi film hydrogen sensor was reduced. The output response, response time and recovery time of the PdNi film hydrogen sensors under the hydrogen concentration of 0.5%, 1.0%, 1.5% and 2.0% were measured at 313 K. The output response of the PdNi thin film hydrogen sensors increased with increasing hydrogen concentration while the response time and recovery time decreased. A cycling test between pure nitrogen and 3% hydrogen concentration was performed at 313 K and PdNi thin film hydrogen sensor demonstrated great repeatability in the cycling test. PMID:29301220

Optical temperature sensor using thermochromic semiconductors

DOEpatents

Kronberg, J.W.

1998-06-30

An optical temperature measuring device utilizes thermochromic semiconductors which vary in color in response to changes in temperature. The thermochromic material is sealed in a glass matrix which allows the temperature sensor to detect high temperatures without breakdown. Cuprous oxide and cadmium sulfide are among the semiconductor materials which provide the best results. The changes in color may be detected visually using a sensor chip and an accompanying color card. 8 figs.

Slot Antenna Integrated Re-Entrant Resonator Based Wireless Pressure Sensor for High-Temperature Applications.

PubMed

Su, Shujing; Lu, Fei; Wu, Guozhu; Wu, Dezhi; Tan, Qiulin; Dong, Helei; Xiong, Jijun

2017-08-25

The highly sensitive pressure sensor presented in this paper aims at wireless passive sensing in a high temperature environment by using microwave backscattering technology. The structure of the re-entrant resonator was analyzed and optimized using theoretical calculation, software simulation, and its equivalent lump circuit model was first modified by us. Micro-machining and high-temperature co-fired ceramic (HTCC) process technologies were applied to fabricate the sensor, solving the common problem of cavity sealing during the air pressure loading test. In addition, to prevent the response signal from being immersed in the strong background clutter of the hermetic metal chamber, which makes its detection difficult, we proposed two key techniques to improve the signal to noise ratio: the suppression of strong background clutter and the detection of the weak backscattered signal of the sensor. The pressure sensor demonstrated in this paper works well for gas pressure loading between 40 and 120 kPa in a temperature range of 24 °C to 800 °C. The experimental results show that the sensor resonant frequency lies at 2.1065 GHz, with a maximum pressure sensitivity of 73.125 kHz/kPa.

Surface-mount sapphire interferometric temperature sensor.

PubMed

Zhu, Yizheng; Wang, Anbo

2006-08-20

A fiber-optic high-temperature sensor is demonstrated by bonding a 45 degrees -polished single-crystal sapphire fiber on the surface of a sapphire wafer, whose optical thickness is temperature dependent and measured by white-light interferometry. A novel adhesive-free coupling between the silica and sapphire fibers is achieved by fusion splicing, and its performance is characterized. The sensor's interference signal is investigated for its dependence on angular alignment between the fiber and the wafer. A prototype sensor is tested to 1,170 degrees C with a resolution of 0.4 degrees C, demonstrating excellent potential for high-temperature measurement.

Optical fiber voltage sensors for broad temperature ranges

NASA Technical Reports Server (NTRS)

Rose, A. H.; Day, G. W.

1992-01-01

We describe the development of an optical fiber ac voltage sensor for aircraft and spacecraft applications. Among the most difficult specifications to meet for this application is a temperature stability of +/- 1 percent from -65 C to +125 C. This stability requires a careful selection of materials, components, and optical configuration with further compensation using an optical-fiber temperature sensor located near the sensing element. The sensor is a polarimetric design, based on the linear electro-optic effect in bulk Bi4Ge3O12. The temperature sensor is also polarimetric, based on the temperature dependence of the birefringence of bulk SiO2. The temperature sensor output is used to automatically adjust the calibration of the instrument.

An Interoperable Architecture for Air Pollution Early Warning System Based on Sensor Web

NASA Astrophysics Data System (ADS)

Samadzadegan, F.; Zahmatkesh, H.; Saber, M.; Ghazi khanlou, H. J.

2013-09-01

Environmental monitoring systems deal with time-sensitive issues which require quick responses in emergency situations. Handling the sensor observations in near real-time and obtaining valuable information is challenging issues in these systems from a technical and scientific point of view. The ever-increasing population growth in urban areas has caused certain problems in developing countries, which has direct or indirect impact on human life. One of applicable solution for controlling and managing air quality by considering real time and update air quality information gathered by spatially distributed sensors in mega cities, using sensor web technology for developing monitoring and early warning systems. Urban air quality monitoring systems using functionalities of geospatial information system as a platform for analysing, processing, and visualization of data in combination with Sensor Web for supporting decision support systems in disaster management and emergency situations. This system uses Sensor Web Enablement (SWE) framework of the Open Geospatial Consortium (OGC), which offers a standard framework that allows the integration of sensors and sensor data into spatial data infrastructures. SWE framework introduces standards for services to access sensor data and discover events from sensor data streams as well as definition set of standards for the description of sensors and the encoding of measurements. The presented system provides capabilities to collect, transfer, share, process air quality sensor data and disseminate air quality status in real-time. It is possible to overcome interoperability challenges by using standard framework. In a routine scenario, air quality data measured by in-situ sensors are communicated to central station where data is analysed and processed. The extracted air quality status is processed for discovering emergency situations, and if necessary air quality reports are sent to the authorities. This research proposed an

Architecture for an integrated real-time air combat and sensor network simulation

NASA Astrophysics Data System (ADS)

Criswell, Evans A.; Rushing, John; Lin, Hong; Graves, Sara

2007-04-01

An architecture for an integrated air combat and sensor network simulation is presented. The architecture integrates two components: a parallel real-time sensor fusion and target tracking simulation, and an air combat simulation. By integrating these two simulations, it becomes possible to experiment with scenarios in which one or both sides in a battle have very large numbers of primitive passive sensors, and to assess the likely effects of those sensors on the outcome of the battle. Modern Air Power is a real-time theater-level air combat simulation that is currently being used as a part of the USAF Air and Space Basic Course (ASBC). The simulation includes a variety of scenarios from the Vietnam war to the present day, and also includes several hypothetical future scenarios. Modern Air Power includes a scenario editor, an order of battle editor, and full AI customization features that make it possible to quickly construct scenarios for any conflict of interest. The scenario editor makes it possible to place a wide variety of sensors including both high fidelity sensors such as radars, and primitive passive sensors that provide only very limited information. The parallel real-time sensor network simulation is capable of handling very large numbers of sensors on a computing cluster of modest size. It can fuse information provided by disparate sensors to detect and track targets, and produce target tracks.

40 CFR 1065.215 - Pressure transducers, temperature sensors, and dewpoint sensors.

Code of Federal Regulations, 2010 CFR

2010-07-01

... sensors, and dewpoint sensors. 1065.215 Section 1065.215 Protection of Environment ENVIRONMENTAL... Measurement of Engine Parameters and Ambient Conditions § 1065.215 Pressure transducers, temperature sensors, and dewpoint sensors. (a) Application. Use instruments as specified in this section to measure...

Air Force Research Laboratory Sensors Directorate Leadership Legacy, 1960-2011

DTIC Science & Technology

2011-03-01

AFRL -RY-WP-TM-2011-1017 AIR FORCE RESEARCH LABORATORY SENSORS DIRECTORATE LEADERSHIP LEGACY, 1960-2011 Compiled by Raymond C. Rang...Structures Divi- sion, Space Vehicles Directorate, Air Force Research Laboratory , Kirtland AFB, N.M. 7. March 1998 - July 1999, Chief, Integration and... Research Laboratory ( AFRL ), and Deputy Director of the Sensors Direc- torate, Air Force Research

A new ultrasonic temperature measurement system for air conditioners in automobiles

NASA Astrophysics Data System (ADS)

Liao, Teh-Lu; Tsai, Wen-Yuan; Huang, Chih-Feng

2004-02-01

This paper presents a microcomputer-based ultrasonic temperature sensor system to measure the temperature of an air conditioner (AC) in an automobile. It uses the ultrasonic measurement of the changes in the speed of sound in the air to determine the temperature of the environmental air. The changes in the speed of sound are calculated by combining time-of-flight (TOF) and phase shift techniques. This method can work in a wider range than using phase shift alone and is more accurate than the TOF scheme. In the proposed system, we use 40 ± 2 kHz ultrasonic transducers and adopt a single-pass operation. An 89c51 single-chip microcomputer-based binary frequency shift-keyed (BFSK) signal generator and phase detector are designed to record and calculate the TOF, phase shift of the two frequencies and temperature. These data are then sent to either an LCD display or to a PC for calibration and examination. Experimental results show that the proposed measurement system has a high accuracy of ± 0.4 °C from 0 to 80 °C and can reflect the temperature change within 100 ms.

Outlier Detection in Urban Air Quality Sensor Networks.

PubMed

van Zoest, V M; Stein, A; Hoek, G

2018-01-01

Low-cost urban air quality sensor networks are increasingly used to study the spatio-temporal variability in air pollutant concentrations. Recently installed low-cost urban sensors, however, are more prone to result in erroneous data than conventional monitors, e.g., leading to outliers. Commonly applied outlier detection methods are unsuitable for air pollutant measurements that have large spatial and temporal variations as occur in urban areas. We present a novel outlier detection method based upon a spatio-temporal classification, focusing on hourly NO 2 concentrations. We divide a full year's observations into 16 spatio-temporal classes, reflecting urban background vs. urban traffic stations, weekdays vs. weekends, and four periods per day. For each spatio-temporal class, we detect outliers using the mean and standard deviation of the normal distribution underlying the truncated normal distribution of the NO 2 observations. Applying this method to a low-cost air quality sensor network in the city of Eindhoven, the Netherlands, we found 0.1-0.5% of outliers. Outliers could reflect measurement errors or unusual high air pollution events. Additional evaluation using expert knowledge is needed to decide on treatment of the identified outliers. We conclude that our method is able to detect outliers while maintaining the spatio-temporal variability of air pollutant concentrations in urban areas.

Temperature measurement method using temperature coefficient timing for resistive or capacitive sensors

DOEpatents

Britton, Jr., Charles L.; Ericson, M. Nance

1999-01-01

A method and apparatus for temperature measurement especially suited for low cost, low power, moderate accuracy implementation. It uses a sensor whose resistance varies in a known manner, either linearly or nonlinearly, with temperature, and produces a digital output which is proportional to the temperature of the sensor. The method is based on performing a zero-crossing time measurement of a step input signal that is double differentiated using two differentiators functioning as respective first and second time constants; one temperature stable, and the other varying with the sensor temperature.

Temperature measurement method using temperature coefficient timing for resistive or capacitive sensors

DOEpatents

Britton, C.L. Jr.; Ericson, M.N.

1999-01-19

A method and apparatus for temperature measurement especially suited for low cost, low power, moderate accuracy implementation. It uses a sensor whose resistance varies in a known manner, either linearly or nonlinearly, with temperature, and produces a digital output which is proportional to the temperature of the sensor. The method is based on performing a zero-crossing time measurement of a step input signal that is double differentiated using two differentiators functioning as respective first and second time constants; one temperature stable, and the other varying with the sensor temperature. 5 figs.

High Temperature, Wireless Seismometer Sensor for Venus

NASA Technical Reports Server (NTRS)

Ponchak, George E.; Scardelletti, Maximilian C.; Taylor, Brandt; Beard, Steve; Meredith, Roger D.; Beheim, Glenn M.; Hunter Gary W.; Kiefer, Walter S.

2012-01-01

Space agency mission plans state the need to measure the seismic activity on Venus. Because of the high temperature on Venus (462? C average surface temperature) and the difficulty in placing and wiring multiple sensors using robots, a high temperature, wireless sensor using a wide bandgap semiconductor is an attractive option. This paper presents the description and proof of concept measurements of a high temperature, wireless seismometer sensor for Venus. A variation in inductance of a coil caused by the movement of an aluminum probe held in the coil and attached to a balanced leaf-spring seismometer causes a variation of 700 Hz in the transmitted signal from the oscillator/sensor system at 426? C. This result indicates that the concept may be used on Venus.

Diode-Laser Absorption Sensor for Line-of-Sight Gas Temperature Distributions

NASA Astrophysics Data System (ADS)

Sanders, Scott T.; Wang, Jian; Jeffries, Jay B.; Hanson, Ronald K.

2001-08-01

Line-of-sight diode-laser absorption techniques have been extended to enable temperature measurements in nonuniform-property flows. The sensing strategy for such flows exploits the broad wavelength-scanning abilities ( >1.7 nm ~ 30 cm-1 ) of a vertical cavity surface-emitting laser (VCSEL) to interrogate multiple absorption transitions along a single line of sight. To demonstrate the strategy, a VCSEL-based sensor for oxygen gas temperature distributions was developed. A VCSEL beam was directed through paths containing atmospheric-pressure air with known (and relatively simple) temperature distributions in the 200 -700 K range. The VCSEL was scanned over ten transitions in the R branch of the oxygen A band near 760 nm and optionally over six transitions in the P branch. Temperature distribution information can be inferred from these scans because the line strength of each probed transition has a unique temperature dependence; the measurement accuracy and resolution depend on the details of this temperature dependence and on the total number of lines scanned. The performance of the sensing strategy can be optimized and predicted theoretically. Because the sensor exhibits a fast time response ( ~30 ms) and can be adapted to probe a variety of species over a range of temperatures and pressures, it shows promise for industrial application.

A Survey of Wireless Sensor Network Based Air Pollution Monitoring Systems

PubMed Central

Yi, Wei Ying; Lo, Kin Ming; Mak, Terrence; Leung, Kwong Sak; Leung, Yee; Meng, Mei Ling

2015-01-01

The air quality in urban areas is a major concern in modern cities due to significant impacts of air pollution on public health, global environment, and worldwide economy. Recent studies reveal the importance of micro-level pollution information, including human personal exposure and acute exposure to air pollutants. A real-time system with high spatio-temporal resolution is essential because of the limited data availability and non-scalability of conventional air pollution monitoring systems. Currently, researchers focus on the concept of The Next Generation Air Pollution Monitoring System (TNGAPMS) and have achieved significant breakthroughs by utilizing the advance sensing technologies, MicroElectroMechanical Systems (MEMS) and Wireless Sensor Network (WSN). However, there exist potential problems of these newly proposed systems, namely the lack of 3D data acquisition ability and the flexibility of the sensor network. In this paper, we classify the existing works into three categories as Static Sensor Network (SSN), Community Sensor Network (CSN) and Vehicle Sensor Network (VSN) based on the carriers of the sensors. Comprehensive reviews and comparisons among these three types of sensor networks were also performed. Last but not least, we discuss the limitations of the existing works and conclude the objectives that we want to achieve in future systems. PMID:26703598

A Survey of Wireless Sensor Network Based Air Pollution Monitoring Systems.

PubMed

Yi, Wei Ying; Lo, Kin Ming; Mak, Terrence; Leung, Kwong Sak; Leung, Yee; Meng, Mei Ling

2015-12-12

The air quality in urban areas is a major concern in modern cities due to significant impacts of air pollution on public health, global environment, and worldwide economy. Recent studies reveal the importance of micro-level pollution information, including human personal exposure and acute exposure to air pollutants. A real-time system with high spatio-temporal resolution is essential because of the limited data availability and non-scalability of conventional air pollution monitoring systems. Currently, researchers focus on the concept of The Next Generation Air Pollution Monitoring System (TNGAPMS) and have achieved significant breakthroughs by utilizing the advance sensing technologies, MicroElectroMechanical Systems (MEMS) and Wireless Sensor Network (WSN). However, there exist potential problems of these newly proposed systems, namely the lack of 3D data acquisition ability and the flexibility of the sensor network. In this paper, we classify the existing works into three categories as Static Sensor Network (SSN), Community Sensor Network (CSN) and Vehicle Sensor Network (VSN) based on the carriers of the sensors. Comprehensive reviews and comparisons among these three types of sensor networks were also performed. Last but not least, we discuss the limitations of the existing works and conclude the objectives that we want to achieve in future systems.

Temperature measurement and damage detection in concrete beams exposed to fire using PPP-BOTDA based fiber optic sensors

NASA Astrophysics Data System (ADS)

Bao, Yi; Hoehler, Matthew S.; Smith, Christopher M.; Bundy, Matthew; Chen, Genda

2017-10-01

In this study, Brillouin scattering-based distributed fiber optic sensor is implemented to measure temperature distributions and detect cracks in concrete structures subjected to fire for the first time. A telecommunication-grade optical fiber is characterized as a high temperature sensor with pulse pre-pump Brillouin optical time domain analysis (PPP-BODTA), and implemented to measure spatially-distributed temperatures in reinforced concrete beams in fire. Four beams were tested to failure in a natural gas fueled compartment fire, each instrumented with one fused silica, single-mode optical fiber as a distributed sensor and four thermocouples. Prior to concrete cracking, the distributed temperature was validated at locations of the thermocouples by a relative difference of less than 9%. The cracks in concrete can be identified as sharp peaks in the temperature distribution since the cracks are locally filled with hot air. Concrete cracking did not affect the sensitivity of the distributed sensor but concrete spalling broke the optical fiber loop required for PPP-BOTDA measurements.

Temperature compensated and self-calibrated current sensor

DOEpatents

Yakymyshyn, Christopher Paul; Brubaker, Michael Allen; Yakymyshyn, Pamela Jane

2007-09-25

A method is described to provide temperature compensation and reduction of drift due to aging for a current sensor based on a plurality of magnetic field sensors positioned around a current carrying conductor. The offset voltage signal generated by each magnetic field sensor is used to correct variations in the output signal due to temperature variations and aging.

An Integrated-Circuit Temperature Sensor for Calorimetry and Differential Temperature Measurement

NASA Astrophysics Data System (ADS)

Muyskens, Mark

1997-07-01

Our application of an integrated-circuit (IC) temperature sensor which is easy-to-use, inexpensive, rugged, easily computer-interfacable and has good precision is described. The design, based on the National Semiconductor LM35 IC chip, avoids some of the difficulties associated with conventional sensors (thermocouples, thermistors, and platinum resistance thermometers) and a previously described IC sensor. The sensor can be used with a variety of data-acquisition systems. Applications range from general chemistry to physical chemistry, particularly where computer interfaced, digital temperature measurement is desired. Included is a detailed description of our current design with suggestions for improvement and a performance evaluation of the precision in differential measurement and the time constant for responding to temperature change.

Threshold temperature optical fibre sensors

NASA Astrophysics Data System (ADS)

Stasiewicz, K. A.; Musial, J. E.

2016-12-01

This paper presents a new approach to manufacture a threshold temperature sensor based on a biconical optical fibre taper. The presented sensor employs the influence of variable state of concentration of some isotropic materials like wax or paraffin. Application of the above- mentioned materials is an attempt to prove that there is a possibility to obtain a low-cost, repeatable and smart sensor working as an in-line element. Optical fibre taper was obtained from a standard single mode fibre (SMF28®) by using a low pressure gas burner technique. The diameter of the manufactured tapers was 6.0 ± 0.5 μm with the length of elongation equal to 30.50 ± 0.16 mm. The applied technology allowed to produce tapers with the losses of 0.183 ± 0.015 dB. Application of materials with different temperature transition points made it possible to obtain the threshold work at the temperatures connected directly with their conversion temperature. External materials at the temperatures above their melting points do not influence the propagation losses. For each of them two types of the protection area and position of the optical fibre taper were applied.

46 CFR 153.440 - Cargo temperature sensors.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 46 Shipping 5 2011-10-01 2011-10-01 false Cargo temperature sensors. 153.440 Section 153.440... CARRYING BULK LIQUID, LIQUEFIED GAS, OR COMPRESSED GAS HAZARDOUS MATERIALS Design and Equipment Cargo Temperature Control Systems § 153.440 Cargo temperature sensors. (a) Except as prescribed in paragraph (c) of...

46 CFR 153.440 - Cargo temperature sensors.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 46 Shipping 5 2010-10-01 2010-10-01 false Cargo temperature sensors. 153.440 Section 153.440... CARRYING BULK LIQUID, LIQUEFIED GAS, OR COMPRESSED GAS HAZARDOUS MATERIALS Design and Equipment Cargo Temperature Control Systems § 153.440 Cargo temperature sensors. (a) Except as prescribed in paragraph (c) of...

Pristine carbon nanotubes based resistive temperature sensor

DOE Office of Scientific and Technical Information (OSTI.GOV)

Alam, Md Bayazeed, E-mail: bayazeed786@gmail.com; Jamia Millia Islamia; Saini, Sudhir Kumar, E-mail: sudhirsaini1310@gmail.com

A good sensor must be highly sensitive, faster in response, of low cost cum easily producible, and highly reliable. Incorporation of nano-dimensional particles/ wires makes conventional sensors more effective in terms of fulfilling the above requirements. For example, Carbon Nanotubes (CNTs) are promising sensing element because of its large aspect ratio, unique electronic and thermal properties. In addition to their use for widely reported chemical sensing, it has also been explored for temperature sensing. This paper presents the fabrication of CNTs based temperature sensor, prepared on silicon substrate using low cost spray coating method, which is reliable and reproducible methodmore » to prepare uniform CNTs thin films on any substrate. Besides this, simple and inexpensive method of preparation of dispersion of single walled CNTs (SWNTs) in 1,2 dichlorobenzene by using probe type ultrasonicator for debundling the CNTs for improving sensor response were used. The electrical contacts over the dispersed SWNTs were taken using silver paste electrodes. Fabricated sensors clearly show immediate change in resistance as a response to change in temperature of SWNTs. The measured sensitivity (change in resistance with temperature) of the sensor was found ∼ 0.29%/°C in the 25°C to 60°C temperature range.« less

Chip-to-chip SnO2 nanowire network sensors for room temperature H2 detection

NASA Astrophysics Data System (ADS)

Köck, A.; Brunet, E.; Mutinati, G. C.; Maier, T.; Steinhauer, S.

2012-06-01

The employment of nanowires is a very powerful strategy to improve gas sensor performance. We demonstrate a gas sensor device, which is based on silicon chip-to-chip synthesis of ultralong tin oxide (SnO2) nanowires. The sensor device employs an interconnected SnO2 nanowire network configuration, which exhibits a huge surface-to-volume ratio and provides full access of the target gas to the nanowires. The chip-to-chip SnO2 nanowire device is able to detect a H2 concentration of only 20 ppm in synthetic air with ~ 60% relative humidity at room temperature. At an operating temperature of 300°C a concentration of 50 ppm H2 results in a sensitivity of 5%. At this elevated temperature the sensor shows a linear response in a concentration range between 10 ppm and 100 ppm H2. The SnO2-nanowire fabrication procedure based on spray pyrolysis and subsequent annealing is performed at atmospheric pressure, requires no vacuum and allows upscale of the substrate to a wafer size. 3D-integration with CMOS chips is proposed as viable way for practical realization of smart nanowire based gas sensor devices for the consumer market.

Thermoelectric Control Of Temperatures Of Pressure Sensors

NASA Technical Reports Server (NTRS)

Burkett, Cecil G., Jr.; West, James W.; Hutchinson, Mark A.; Lawrence, Robert M.; Crum, James R.

1995-01-01

Prototype controlled-temperature enclosure containing thermoelectric devices developed to house electronically scanned array of pressure sensors. Enclosure needed because (1) temperatures of transducers in sensors must be maintained at specified set point to ensure proper operation and calibration and (2) sensors sometimes used to measure pressure in hostile environments (wind tunnels in original application) that are hotter or colder than set point. Thus, depending on temperature of pressure-measurement environment, thermoelectric devices in enclosure used to heat or cool transducers to keep them at set point.

Multiple Waveband Temperature Sensor (MWTS)

NASA Technical Reports Server (NTRS)

Bandara, Sumith V.; Gunapala, Sarath; Wilson, Daniel; Stirbl, Robert; Blea, Anthony; Harding, Gilbert

2006-01-01

This slide presentation reviews the development of Multiple Waveband Temperature Sensor (MWTS). The MWTS project will result in a highly stable, monolithically integrated, high resolution infrared detector array sensor that records registered thermal imagery in four infrared wavebands to infer dynamic temperature profiles on a laser-irradiated ground target. An accurate surface temperature measurement of a target in extreme environments in a non-intrusive manner is required. The development challenge is to: determine optimum wavebands (suitable for target temperatures, nature of the targets and environments) to measure accurate target surface temperature independent of the emissivity, integrate simultaneously readable multiband Quantum Well Infrared Photodetectors (QWIPs) in a single monolithic focal plane array (FPA) sensor and to integrate the hardware/software and system calibration for remote temperature measurements. The charge was therefore to develop and demonstrate a multiband infrared imaging camera with the detectors simultaneously sensitive to multiple distinct color bands for front surface temperature measurements Wavelength ( m) measurements. Amongst the requirements are: that the measurement system will not affect target dynamics or response to the laser irradiation and that the simplest criterion for spectral band selection is to choose those practically feasible spectral bands that create the most contrast between the objects or scenes of interest in the expected environmental conditions. There is in the presentation a review of the modeling and simulation of multi-wave infrared temperature measurement and also a review of the detector development and QWIP capacities.

Battery system with temperature sensors

DOEpatents

Wood, Steven J.; Trester, Dale B.

2012-11-13

A battery system to monitor temperature includes at least one cell with a temperature sensing device proximate the at least one cell. The battery system also includes a flexible member that holds the temperature sensor proximate to the at least one cell.

Sapphire Fabry-Perot high-temperature sensor study

NASA Astrophysics Data System (ADS)

Yao, Yi-qiang; Liang, Wei-long; Gui, Xinwang; Fan, Dian

2017-04-01

A new structure sapphire fiber Fabry-Perot (F-P) high-temperature sensor based on sapphire wafer was proposed and fabricated. The sensor uses the sapphire fiber as a transmission waveguide, the sapphire wafer as an Fabry-Perot (F-P) interferometer and the new structure of "Zirconia ferrule-Zirconia tube" as the sensor fixing structure of the sensor. The reflection spectrum of the interferometer was demodulated by a serial of data processing including FIR bandpass filter, FFT (Fast Fourier Transformation) estimation and LSE (least squares estimation) compensation to obtain more precise OPD. Temperature measurement range is from 20 to 1000°C in experiment. The experimental results show that the sensor has the advantages of small size, low cost, simple fabrication and high repeatability. It can be applied for longterm, stable and high-precision high temperature measurement in harsh environments.

Measuring PM and related air pollutants using low-cost sensors

EPA Science Inventory

Emerging air quality sensors may play a key role in better characterizing levels of air pollution in a variety of settings There are a wide range of low-cost (< $500 US) sensors on the market, but few have been characterized. If accurate, this new generation of inexpensive sens...

Silicon-etalon fiber-optic temperature sensor

NASA Technical Reports Server (NTRS)

Beheim, Glenn; Fritsch, Klaus; Flatico, Joseph M.; Azar, Massood Tabib

1989-01-01

A temperature sensor is described which consists of a silicon etalon that is sputtered directly onto the end of an optical fiber. A two-layer protective cap structure is used to improve the sensor's long-term stability. The sensor's output is wavelength encoded to provide a high degree of immunity from cable and connector effects. This sensor is extremely compact and potentially inexpensive.

A Wind Energy Powered Wireless Temperature Sensor Node

PubMed Central

Zhang, Chuang; He, Xue-Feng; Li, Si-Yu; Cheng, Yao-Qing; Rao, Yang

2015-01-01

A wireless temperature sensor node composed of a piezoelectric wind energy harvester, a temperature sensor, a microcontroller, a power management circuit and a wireless transmitting module was developed. The wind-induced vibration energy harvester with a cuboid chamber of 62 mm × 19.6 mm × 10 mm converts ambient wind energy into electrical energy to power the sensor node. A TMP102 temperature sensor and the MSP430 microcontroller are used to measure the temperature. The power management module consists of LTC3588-1 and LT3009 units. The measured temperature is transmitted by the nRF24l01 transceiver. Experimental results show that the critical wind speed of the harvester was about 5.4 m/s and the output power of the harvester was about 1.59 mW for the electrical load of 20 kΩ at wind speed of 11.2 m/s, which was sufficient to power the wireless sensor node to measure and transmit the temperature every 13 s. When the wind speed increased from 6 m/s to 11.5 m/s, the self-powered wireless sensor node worked normally. PMID:25734649

A wind energy powered wireless temperature sensor node.

PubMed

Zhang, Chuang; He, Xue-Feng; Li, Si-Yu; Cheng, Yao-Qing; Rao, Yang

2015-02-27

A wireless temperature sensor node composed of a piezoelectric wind energy harvester, a temperature sensor, a microcontroller, a power management circuit and a wireless transmitting module was developed. The wind-induced vibration energy harvester with a cuboid chamber of 62 mm × 19.6 mm × 10 mm converts ambient wind energy into electrical energy to power the sensor node. A TMP102 temperature sensor and the MSP430 microcontroller are used to measure the temperature. The power management module consists of LTC3588-1 and LT3009 units. The measured temperature is transmitted by the nRF24l01 transceiver. Experimental results show that the critical wind speed of the harvester was about 5.4 m/s and the output power of the harvester was about 1.59 mW for the electrical load of 20 kΩ at wind speed of 11.2 m/s, which was sufficient to power the wireless sensor node to measure and transmit the temperature every 13 s. When the wind speed increased from 6 m/s to 11.5 m/s, the self-powered wireless sensor node worked normally.

Crowdsourcing urban air temperatures from smartphone battery temperatures

NASA Astrophysics Data System (ADS)

Overeem, A.; Robinson, J. C. R.; Leijnse, H.; Steeneveld, G. J.; Horn, B. K. P.; Uijlenhoet, R.

2013-08-01

Accurate air temperature observations in urban areas are important for meteorology and energy demand planning. They are indispensable to study the urban heat island effect and the adverse effects of high temperatures on human health. However, the availability of temperature observations in cities is often limited. Here we show that relatively accurate air temperature information for the urban canopy layer can be obtained from an alternative, nowadays omnipresent source: smartphones. In this study, battery temperatures were collected by an Android application for smartphones. A straightforward heat transfer model is employed to estimate daily mean air temperatures from smartphone battery temperatures for eight major cities around the world. The results demonstrate the enormous potential of this crowdsourcing application for real-time temperature monitoring in densely populated areas.

Fabrication method for a room temperature hydrogen sensor

NASA Technical Reports Server (NTRS)

Shukla, Satyajit V. (Inventor); Cho, Hyoung (Inventor); Seal, Sudipta (Inventor); Ludwig, Lawrence (Inventor)

2011-01-01

A sensor for selectively determining the presence and measuring the amount of hydrogen in the vicinity of the sensor. The sensor comprises a MEMS device coated with a nanostructured thin film of indium oxide doped tin oxide with an over layer of nanostructured barium cerate with platinum catalyst nanoparticles. Initial exposure to a UV light source, at room temperature, causes burning of organic residues present on the sensor surface and provides a clean surface for sensing hydrogen at room temperature. A giant room temperature hydrogen sensitivity is observed after making the UV source off. The hydrogen sensor of the invention can be usefully employed for the detection of hydrogen in an environment susceptible to the incursion or generation of hydrogen and may be conveniently used at room temperature.

Perceiving nasal patency through mucosal cooling rather than air temperature or nasal resistance.

PubMed

Zhao, Kai; Blacker, Kara; Luo, Yuehao; Bryant, Bruce; Jiang, Jianbo

2011-01-01

Adequate perception of nasal airflow (i.e., nasal patency) is an important consideration for patients with nasal sinus diseases. The perception of a lack of nasal patency becomes the primary symptom that drives these patients to seek medical treatment. However, clinical assessment of nasal patency remains a challenge because we lack objective measurements that correlate well with what patients perceive. The current study examined factors that may influence perceived patency, including air temperature, humidity, mucosal cooling, nasal resistance, and trigeminal sensitivity. Forty-four healthy subjects rated nasal patency while sampling air from three facial exposure boxes that were ventilated with untreated room air, cold air, and dry air, respectively. In all conditions, air temperature and relative humidity inside each box were recorded with sensors connected to a computer. Nasal resistance and minimum airway cross-sectional area (MCA) were measured using rhinomanometry and acoustic rhinometry, respectively. General trigeminal sensitivity was assessed through lateralization thresholds to butanol. No significant correlation was found between perceived patency and nasal resistance or MCA. In contrast, air temperature, humidity, and butanol threshold combined significantly contributed to the ratings of patency, with mucosal cooling (heat loss) being the most heavily weighted predictor. Air humidity significantly influences perceived patency, suggesting that mucosal cooling rather than air temperature alone provides the trigeminal sensation that results in perception of patency. The dynamic cooling between the airstream and the mucosal wall may be quantified experimentally or computationally and could potentially lead to a new clinical evaluation tool.

Effect of Water Vapor and Surface Morphology on the Low Temperature Response of Metal Oxide Semiconductor Gas Sensors

PubMed Central

Maier, Konrad; Helwig, Andreas; Müller, Gerhard; Hille, Pascal; Eickhoff, Martin

2015-01-01

In this work the low temperature response of metal oxide semiconductor gas sensors is analyzed. Important characteristics of this low-temperature response are a pronounced selectivity to acid- and base-forming gases and a large disparity of response and recovery time constants which often leads to an integrator-type of gas response. We show that this kind of sensor performance is related to the trend of semiconductor gas sensors to adsorb water vapor in multi-layer form and that this ability is sensitively influenced by the surface morphology. In particular we show that surface roughness in the nanometer range enhances desorption of water from multi-layer adsorbates, enabling them to respond more swiftly to changes in the ambient humidity. Further experiments reveal that reactive gases, such as NO2 and NH3, which are easily absorbed in the water adsorbate layers, are more easily exchanged across the liquid/air interface when the humidity in the ambient air is high. PMID:28793583

Plug-in Sensors for Air Pollution Monitoring.

ERIC Educational Resources Information Center

Shaw, Manny

Faristors, a type of plug-in sensors used in analyzing equipment, are described in this technical report presented at the 12th Conference on Methods in Air Pollution and Industrial Hygiene Studies, University of Southern California, April, 1971. Their principles of operation, interchangeability, and versatility for measuring air pollution at…

Low-Cost Sensor Units for Measuring Urban Air Quality

NASA Astrophysics Data System (ADS)

Popoola, O. A.; Mead, M.; Stewart, G.; Hodgson, T.; McLoed, M.; Baldovi, J.; Landshoff, P.; Hayes, M.; Calleja, M.; Jones, R.

2010-12-01

Measurements of selected key air quality gases (CO, NO & NO2) have been made with a range of miniature low-cost sensors based on electrochemical gas sensing technology incorporating GPS and GPRS for position and communication respectively. Two types of simple to operate sensors units have been designed to be deployed in relatively large numbers. Mobile handheld sensor units designed for operation by members of the public have been deployed on numerous occasions including in Cambridge, London and Valencia. Static sensor units have also been designed for long-term autonomous deployment on existing street furniture. A study was recently completed in which 45 sensor units were deployed in the Cambridge area for a period of 3 months. Results from these studies indicate that air quality varies widely both spatially and temporally. The widely varying concentrations found suggest that the urban environment cannot be fully understood using limited static site (AURN) networks and that a higher resolution, more dispersed network is required to better define air quality in the urban environment. The results also suggest that higher spatial and temporal resolution measurements could improve knowledge of the levels of individual exposure in the urban environment.

Respiration and heartbeat signal detection from airflow at airway in rat by catheter flow sensor with temperature compensation function

NASA Astrophysics Data System (ADS)

Hasegawa, Y.; Kawaoka, H.; Yamada, T.; Matsushima, M.; Kawabe, T.; Shikida, M.

2017-12-01

We previously proposed an evaluation method for detecting both respiration and heartbeat signals from the airflow at the mouth (Kawaoka et al 201518th Int. Conf. on Solid-State Sensors, Actuators and Microsystems; Kawaoka et al 2015 IEEE Sensors; Kawaoka et al 2016 Technical Digest IEEE Micro Electro Mechanical Systems Conf.). In the current study, we developed a catheter flow sensor with temperature compensation that uses MEMS technologies and used it to directly detect the breathing airflow in the airway of a rat. The temperature sensors were integrated with the catheter flow sensor. Heaters working as airflow and temperature sensors were produced on polymer film by using the same fabrication process so that the temperature coefficients of their resistances would coincide. As a result, the variation in sensor outputs due to the airflow temperature changes ranging from 20 °C to 34 °C was suppressed to less than 2.5%. The developed catheter flow sensor was inserted into the airway of a rat to detect both respiration and heartbeat signals. The accuracy of the breathing airflow measurements was improved thanks to the temperature compensation. The tidal volume variations between the expired and inspired air were suppressed to within 5%. Heartbeat signal information was extracted from the measured breathing waveforms by applying a discrete Fourier transform.

Air Temperature Distribution Measurement Using Asynchronous-Type Sound Probe

NASA Astrophysics Data System (ADS)

Katano, Yosuke; Wakatsuki, Naoto; Mizutani, Koichi

2009-07-01

In conventional temperature measurement using a sound probe, the operation beginnings of two acoustic sensors must be completely synchronized to measure time of flight (TOF), tf, because the precision of synchronization determines TOF measurement accuracy. A wireless local area network (LAN) is convenient for constructing a sensing grid; however, it causes a fluctuation in the delay of millisecond order. Therefore, it cannot provide sufficient precision for synchronizing acoustic sensors. In previous studies, synchronization was achieved by a trigger line using a coaxial cable; however, the cable reduces the flexibility of a wireless sensing grid especially in larger-scale measurement. In this study, an asynchronous-type sound probe is devised to compensate for the effect of the delay of millisecond order caused by the network. The validity of the probe was examined, and the air temperature distribution was measured using this means. A matrix method is employed to obtain the distribution. Similar results were observed using both asynchronous-type sound probes and thermocouples. This shows the validity of the use of a sensing grid with an asynchronous-type sound probe for temperature distribution measurement even if the trigger line is omitted.

A New Black Carbon Sensor for Dense Air Quality Monitoring Networks

PubMed Central

Caubel, Julien J.; Cados, Troy E.; Kirchstetter, Thomas W.

2018-01-01

Low-cost air pollution sensors are emerging and increasingly being deployed in densely distributed wireless networks that provide more spatial resolution than is typical in traditional monitoring of ambient air quality. However, a low-cost option to measure black carbon (BC)—a major component of particulate matter pollution associated with adverse human health risks—is missing. This paper presents a new BC sensor designed to fill this gap, the Aerosol Black Carbon Detector (ABCD), which incorporates a compact weatherproof enclosure, solar-powered rechargeable battery, and cellular communication to enable long-term, remote operation. This paper also demonstrates a data processing methodology that reduces the ABCD’s sensitivity to ambient temperature fluctuations, and therefore improves measurement performance in unconditioned operating environments (e.g., outdoors). A fleet of over 100 ABCDs was operated outdoors in collocation with a commercial BC instrument (Magee Scientific, Model AE33) housed inside a regulatory air quality monitoring station. The measurement performance of the 105 ABCDs is comparable to the AE33. The fleet-average precision and accuracy, expressed in terms of mean absolute percentage error, are 9.2 ± 0.8% (relative to the fleet average data) and 24.6 ± 0.9% (relative to the AE33 data), respectively (fleet-average ± 90% confidence interval). PMID:29494528

A New Black Carbon Sensor for Dense Air Quality Monitoring Networks.

PubMed

Caubel, Julien J; Cados, Troy E; Kirchstetter, Thomas W

2018-03-01

Low-cost air pollution sensors are emerging and increasingly being deployed in densely distributed wireless networks that provide more spatial resolution than is typical in traditional monitoring of ambient air quality. However, a low-cost option to measure black carbon (BC)-a major component of particulate matter pollution associated with adverse human health risks-is missing. This paper presents a new BC sensor designed to fill this gap, the Aerosol Black Carbon Detector (ABCD), which incorporates a compact weatherproof enclosure, solar-powered rechargeable battery, and cellular communication to enable long-term, remote operation. This paper also demonstrates a data processing methodology that reduces the ABCD's sensitivity to ambient temperature fluctuations, and therefore improves measurement performance in unconditioned operating environments (e.g., outdoors). A fleet of over 100 ABCDs was operated outdoors in collocation with a commercial BC instrument (Magee Scientific, Model AE33) housed inside a regulatory air quality monitoring station. The measurement performance of the 105 ABCDs is comparable to the AE33. The fleet-average precision and accuracy, expressed in terms of mean absolute percentage error, are 9.2 ± 0.8% (relative to the fleet average data) and 24.6 ± 0.9% (relative to the AE33 data), respectively (fleet-average ± 90% confidence interval).

Wireless sensor for temperature and humidity measurement

NASA Astrophysics Data System (ADS)

Drumea, Andrei; Svasta, Paul

2010-11-01

Temperature and humidity sensors have a broad range of applications, from heating and ventilation of houses to controlled drying of fruits, vegetables or meat in food industry. Modern sensors are integrated devices, usually MEMS, factory-calibrated and with digital output of measured parameters. They can have power down modes for reduced energy consumption. Such an integrated device allows the implementation of a battery powered wireless sensor when coupled with a low power microcontroller and a radio subsystem. A radio sensor can work independently or together with others in a radio network. Presented paper focuses mainly on measurement and construction aspects of sensors for temperature and humidity designed and implemented by authors; network aspects (communication between two or more sensors) are not analyzed.

Temperature compensated current sensor using reference magnetic field

DOEpatents

Yakymyshyn, Christopher Paul; Brubaker, Michael Allen; Yakymyshyn, Pamela Jane

2007-10-09

A method is described to provide temperature compensation and self-calibration of a current sensor based on a plurality of magnetic field sensors positioned around a current carrying conductor. A reference magnetic field generated within the current sensor housing is detected by a separate but identical magnetic field sensor and is used to correct variations in the output signal due to temperature variations and aging.

Development of metal-ceramic coaxial cable Fabry-Pérot interferometric sensors for high temperature monitoring

DOE PAGES

Trontz, Adam; Cheng, Baokai; Zeng, Shixuan; ...

2015-09-25

Metal-ceramic coaxial cable Fabry-Pérot interferometric (MCCC-FPI) sensors have been developed using a stainless steel tube and a stainless steel wire as the outer and inner conductors, respectively; a tubular α-alumina insulator; and a pair of air gaps created in the insulator along the cable to serve as weak reflectors for the transmitting microwave (MW) signal. The MCCC-FPI sensors have been demonstrated for high temperature measurements using MW signals in a frequency range of 2–8 GHz. The temperature measurement is achieved by monitoring the frequency shift (Δƒ) of the MW interferogram reflected from the pair of weak reflectors. The MW sensormore » exhibited excellent linear dependence of Δƒ on temperature; small measurement deviations (±2.7%); and fast response in a tested range of 200–500 °C. The MCCC has the potential for further developing multipoint FPI sensors in a single-cable to achieve in situ and continuous measurement of spatially distributed temperature in harsh environments.« less

A Wide Range Temperature Sensor Using SOI Technology

NASA Technical Reports Server (NTRS)

Patterson, Richard L.; Elbuluk, Malik E.; Hammoud, Ahmad

2009-01-01

Silicon-on-insulator (SOI) technology is becoming widely used in integrated circuit chips for its advantages over the conventional silicon counterpart. The decrease in leakage current combined with lower power consumption allows electronics to operate in a broader temperature range. This paper describes the performance of an SOIbased temperature sensor under extreme temperatures and thermal cycling. The sensor comprised of a temperature-to-frequency relaxation oscillator circuit utilizing an SOI precision timer chip. The circuit was evaluated under extreme temperature exposure and thermal cycling between -190 C and +210 C. The results indicate that the sensor performed well over the entire test temperature range and it was able to re-start at extreme temperatures.

Development of wireless sensor network for monitoring indoor air pollutant

NASA Astrophysics Data System (ADS)

Saad, Shaharil Mad; Shakaff, Ali Yeon Md; Saad, Abdul Rahman Mohd; Yusof @ Kamarudin, Azman Muhamad

2015-05-01

The air that we breathe with everyday contains variety of contaminants and particles. Some of these contaminants and particles are hazardous to human health. Most of the people don't realize that the content of air they being exposed to whether it was a good or bad air quality. The air quality whether in indoor or outdoor environment can be influenced by physical factors like dust particles, gaseous pollutants (including carbon dioxide, carbon monoxide and volatile organic compounds) and biological like molds and bacteria growth which largely depend on temperature and humidity condition of a room. These kinds of pollutants can affect human health, physical reaction, comfort or work performance. In this study, a wireless sensor network (WSN) monitoring system for monitor air pollutant in indoor environment was developed. The system was divided into three parts: web-based interface program, sensing module and a base station. The measured data was displayed on the web which is can be accessed by the user. The result shows that the overall measured parameters were meet the acceptable limit, requirement and criteria of indoor air pollution inside the building. The research can be used to improve the indoor air quality level in order to create a comfortable working and healthy environment for the occupants inside the building.

Effects of room temperature aging on two cryogenic temperature sensor models used in aerospace applications

NASA Astrophysics Data System (ADS)

Courts, S. Scott; Krause, John

2012-06-01

Cryogenic temperature sensors used in aerospace applications are typically procured far in advance of the mission launch date. Depending upon the program, the temperature sensors may be stored at room temperature for extended periods as installation and groundbased testing can take years before the actual flight. The effects of long term storage at room temperature are sometimes approximated by the use of accelerated aging at temperatures well above room temperature, but this practice can yield invalid results as the sensing material and/or electrical contacting method can be increasingly unstable with higher temperature exposure. To date, little data are available on the effects of extended room temperature aging on sensors commonly used in aerospace applications. This research examines two such temperature sensors models - the Lake Shore Cryotronics, Inc. model CernoxTM and DT-670-SD temperature sensors. Sample groups of each model type have been maintained for ten years or longer with room temperature storage between calibrations. Over an eighteen year period, the CernoxTM temperature sensors exhibited a stability of better than ±20 mK for T<30 K and better than ±0.1% of temperature for T>30 K. Over a ten year period the model DT-670-SD sensors exhibited a stability of better than ±140 mK for T<25 K and better than ±75 mK for T>25 K.

Development and Application of a Next Generation Air Sensor Network for the Hong Kong Marathon 2015 Air Quality Monitoring.

PubMed

Sun, Li; Wong, Ka Chun; Wei, Peng; Ye, Sheng; Huang, Hao; Yang, Fenhuan; Westerdahl, Dane; Louie, Peter K K; Luk, Connie W Y; Ning, Zhi

2016-02-05

This study presents the development and evaluation of a next generation air monitoring system with both laboratory and field tests. A multi-parameter algorithm was used to correct for the impact of environmental conditions on the electrochemical sensors for carbon monoxide (CO) and nitrogen dioxide (NO2) pollutants. The field evaluation in an urban roadside environment in comparison to designated monitors showed good agreement with measurement error within 5% of the pollutant concentrations. Multiple sets of the developed system were then deployed in the Hong Kong Marathon 2015 forming a sensor-based network along the marathon route. Real-time air pollution concentration data were wirelessly transmitted and the Air Quality Health Index (AQHI) for the Green Marathon was calculated, which were broadcast to the public on an hourly basis. The route-specific sensor network showed somewhat different pollutant patterns than routine air monitoring, indicating the immediate impact of traffic control during the marathon on the roadside air quality. The study is one of the first applications of a next generation sensor network in international sport events, and it demonstrated the usefulness of the emerging sensor-based air monitoring technology in rapid network deployment to supplement existing air monitoring.

Fiber Optic High Temperature Sensors for Re-Entry Vehicles

NASA Astrophysics Data System (ADS)

Haddad, E.; Kruzelecky, R.; Zou, J.; Wong, B.; Jamroz, W.; Sayeed, F.; Muylaert, J.-M.; McKenzie, I.

2009-01-01

MPB, within an ESA contract, is developing high temperature Fiber sensors (up to 1100°C) for re- ntry experiments, with direct application to the Thermo Protection Surface (TPS) of SHEFEX II. It addresses the challenges of obtaining high reflectivity FBG sensors, and integrating the fiber sensors within the selected TPS host material (C/SiC). Feasibility was demonstrated using free fiber sensors that showed the formation of the Chemical Composition Grating (CCG), with 80 % reflection at temperatures >750°C. The CCG grating was stable at high temperature (1000°C) for more than 50 hours, as well as after cycling between room temperature and 1000°C, with better than 0.5 % temperature accuracy (FBG central wavelength). Small FBG sensor packages were prepared and attached to C/SiC tiles. The calibration of the packaged fibers showed similar response to temperature as the free fiber sensor. The fiber sensor package was designed to maximize contact with the C/SiC surface to provide fast response to transients. Three- imension modeling with Ansys finite element analysis shows a time constant of 15-20 ms to reach 1200°C. A modular design will be implemented where a dedicated fiber line with 3 sensors and its own connector is used for each C/SiC tile. Small coupons of packaged sensors attached to C/SiC tiles will be tested in a re-entry environment at Von Karman Institute (Belgium) In a recently completed project with ESA, MPB developed and ground qualified a fiber sensor network, the "Fiber Sensor Demonstrator", that was successfully integrated as a payload with ESA's Proba-2. The system includes a central interrogation system that can be used to measure multiple parameters including a high temperature sensor for the Proba-2 thruster (up to 500°C).

Packaging Technologies for High Temperature Electronics and Sensors

NASA Technical Reports Server (NTRS)

Chen, Liang-Yu; Hunter, Gary W.; Neudeck, Philip G.; Beheim, Glenn M.; Spry, David J.; Meredith, Roger D.

2013-01-01

This paper reviews ceramic substrates and thick-film metallization based packaging technologies in development for 500 C silicon carbide (SiC) electronics and sensors. Prototype high temperature ceramic chip-level packages and printed circuit boards (PCBs) based on ceramic substrates of aluminum oxide (Al2O3) and aluminum nitride (AlN) have been designed and fabricated. These ceramic substrate-based chip-level packages with gold (Au) thick-film metallization have been electrically characterized at temperatures up to 550 C. A 96% alumina based edge connector for a PCB level subsystem interconnection has also been demonstrated recently. The 96% alumina packaging system composed of chip-level packages and PCBs has been tested with high temperature SiC devices at 500 C for over 10,000 hours. In addition to tests in a laboratory environment, a SiC JFET with a packaging system composed of a 96% alumina chip-level package and an alumina printed circuit board mounted on a data acquisition circuit board was launched as a part of the MISSE-7 suite to the International Space Station via a Shuttle mission. This packaged SiC transistor was successfully tested in orbit for eighteen months. A spark-plug type sensor package designed for high temperature SiC capacitive pressure sensors was developed. This sensor package combines the high temperature interconnection system with a commercial high temperature high pressure stainless steel seal gland (electrical feed-through). Test results of a packaged high temperature capacitive pressure sensor at 500 C are also discussed. In addition to the pressure sensor package, efforts for packaging high temperature SiC diode-based gas chemical sensors are in process.

Packaging Technologies for High Temperature Electronics and Sensors

NASA Technical Reports Server (NTRS)

Chen, Liangyu; Hunter, Gary W.; Neudeck, Philip G.; Beheim, Glenn M.; Spry, David J.; Meredith, Roger D.

2013-01-01

This paper reviews ceramic substrates and thick-film metallization based packaging technologies in development for 500degC silicon carbide (SiC) electronics and sensors. Prototype high temperature ceramic chip-level packages and printed circuit boards (PCBs) based on ceramic substrates of aluminum oxide (Al2O3) and aluminum nitride (AlN) have been designed and fabricated. These ceramic substrate-based chiplevel packages with gold (Au) thick-film metallization have been electrically characterized at temperatures up to 550degC. A 96% alumina based edge connector for a PCB level subsystem interconnection has also been demonstrated recently. The 96% alumina packaging system composed of chip-level packages and PCBs has been tested with high temperature SiC devices at 500degC for over 10,000 hours. In addition to tests in a laboratory environment, a SiC JFET with a packaging system composed of a 96% alumina chip-level package and an alumina printed circuit board mounted on a data acquisition circuit board was launched as a part of the MISSE-7 suite to the International Space Station via a Shuttle mission. This packaged SiC transistor was successfully tested in orbit for eighteen months. A spark-plug type sensor package designed for high temperature SiC capacitive pressure sensors was developed. This sensor package combines the high temperature interconnection system with a commercial high temperature high pressure stainless steel seal gland (electrical feed-through). Test results of a packaged high temperature capacitive pressure sensor at 500degC are also discussed. In addition to the pressure sensor package, efforts for packaging high temperature SiC diode-based gas chemical sensors are in process.

Air Enquirer's multi-sensor boxes as a tool for High School Education and Atmospheric Research

NASA Astrophysics Data System (ADS)

Morguí, Josep-Anton; Font, Anna; Cañas, Lidia; Vázquez-García, Eusebi; Gini, Andrea; Corominas, Ariadna; Àgueda, Alba; Lobo, Agustin; Ferraz, Carlos; Nofuentes, Manel; Ulldemolins, Delmir; Roca, Alex; Kamnang, Armand; Grossi, Claudia; Curcoll, Roger; Batet, Oscar; Borràs, Silvia; Occhipinti, Paola; Rodó, Xavier

2016-04-01

An educational tool was designed with the aim of making more comprehensive the research done on Greenhouse Gases (GHGs) in the ClimaDat Spanish network of atmospheric observation stations (www.climadat.es). This tool is called Air Enquirer and it consist of a multi-sensor box. It is envisaged to build more than two hundred boxes to yield them to the Spanish High Schools through the Education department (www.educaixa.com) of the "Obra Social 'La Caixa'", who funds this research. The starting point for the development of the Air Enquirers was the experience at IC3 (www.ic3.cat) in the CarboSchools+ FP7 project (www.carboschools.cat, www.carboschools.eu). The Air Enquirer's multi-sensor box is based in Arduino's architecture and contains sensors for CO2, temperature, relative humidity, pressure, and both infrared and visible luminance. The Air Enquirer is designed for taking continuous measurements. Every Air Enquirer ensemble of measurements is used to convert values to standard units (water content in ppmv, and CO2 in ppmv_dry). These values are referred to a calibration made with Cavity Ring Down Spectrometry (Picarro®) under different temperature, pressure, humidity and CO2 concentrations. Multiple sets of Air Enquirers are intercalibrated for its use in parallel during the experiments. The different experiments proposed to the students will be outdoor (observational) or indoor (experimental, in the lab) focusing on understanding the biogeochemistry of GHGs in the ecosystems (mainly CO2), the exchange (flux) of gases, the organic matter production, respiration and decomposition processes, the influence of the anthropogenic activities on the gases (and particles) exchanges, and their interaction with the structure and composition of the atmosphere (temperature, water content, cooling and warming processes, radiative forcing, vertical gradients and horizontal patterns). In order to ensure Air Enquirers a high-profile research performance the experimental designs

Asymmetric structured microfiber-based temperature sensor

NASA Astrophysics Data System (ADS)

Xian, Pei; Feng, Guoying; Dai, Shenyu; Zhou, Shouhuan

2017-04-01

A temperature sensor formed by a cascaded sphere and an abrupt taper, together in a standard single-mode fiber, was developed. The dip of the measured spectrum signal shifted obviously when the surrounding temperature changed. Measurement sensitivity to 18.36 pm/°C was shown with the surrounding temperature ranging from 35°C to 395°C. Due to its compact size and all-fiber configuration, the proposed sensor has the advantages of simplicity and low-cost fabrication, thus the device would find potential applications in sensing fields.

Temperature grid sensor for the measurement of spatial temperature distributions at object surfaces.

PubMed

Schäfer, Thomas; Schubert, Markus; Hampel, Uwe

2013-01-25

This paper presents results of the development and application of a new temperature grid sensor based on the wire-mesh sensor principle. The grid sensor consists of a matrix of 256 Pt1000 platinum chip resistors and an associated electronics that measures the grid resistances with a multiplexing scheme at high speed. The individual sensor elements can be spatially distributed on an object surface and measure transient temperature distributions in real time. The advantage compared with other temperature field measurement approaches such as infrared cameras is that the object under investigation can be thermally insulated and the radiation properties of the surface do not affect the measurement accuracy. The sensor principle is therefore suited for various industrial monitoring applications. Its applicability for surface temperature monitoring has been demonstrated through heating and mixing experiments in a vessel.

Body/bone-marrow differential-temperature sensor

NASA Technical Reports Server (NTRS)

Anselmo, V. J.; Berdahl, C. M.

1978-01-01

Differential-temperature sensor developed to compare bone-marrow and body temperature in leukemia patients uses single stable amplifier to monitor temperature difference recorded by thermocouples. Errors are reduced by referencing temperatures to each other, not to separate calibration points.

End-user perspective of low-cost sensors for outdoor air pollution monitoring.

PubMed

Rai, Aakash C; Kumar, Prashant; Pilla, Francesco; Skouloudis, Andreas N; Di Sabatino, Silvana; Ratti, Carlo; Yasar, Ansar; Rickerby, David

2017-12-31

Low-cost sensor technology can potentially revolutionise the area of air pollution monitoring by providing high-density spatiotemporal pollution data. Such data can be utilised for supplementing traditional pollution monitoring, improving exposure estimates, and raising community awareness about air pollution. However, data quality remains a major concern that hinders the widespread adoption of low-cost sensor technology. Unreliable data may mislead unsuspecting users and potentially lead to alarming consequences such as reporting acceptable air pollutant levels when they are above the limits deemed safe for human health. This article provides scientific guidance to the end-users for effectively deploying low-cost sensors for monitoring air pollution and people's exposure, while ensuring reasonable data quality. We review the performance characteristics of several low-cost particle and gas monitoring sensors and provide recommendations to end-users for making proper sensor selection by summarizing the capabilities and limitations of such sensors. The challenges, best practices, and future outlook for effectively deploying low-cost sensors, and maintaining data quality are also discussed. For data quality assurance, a two-stage sensor calibration process is recommended, which includes laboratory calibration under controlled conditions by the manufacturer supplemented with routine calibration checks performed by the end-user under final deployment conditions. For large sensor networks where routine calibration checks are impractical, statistical techniques for data quality assurance should be utilised. Further advancements and adoption of sophisticated mathematical and statistical techniques for sensor calibration, fault detection, and data quality assurance can indeed help to realise the promised benefits of a low-cost air pollution sensor network. Copyright © 2017 Elsevier B.V. All rights reserved.

An FPGA Noise Resistant Digital Temperature Sensor with Auto Calibration

DTIC Science & Technology

2012-03-01

temperature sensor [6] . . . . . . . . . . . . . . 14 9 Two different digital temperature sensor placement algorithms: (a) Grid placement (b) Optimal...create a grid over the FPGA. While this method works reasonably well, it requires many sensors, some of which are unnecessary. The optimal placement, on...temperature sensor placement algorithms: (a) Grid placement (b) Optimal Placement [7] 16 2.4 Summary Integrated circuits’ sensitivity to temperatures has

46 CFR 153.565 - Special requirement for temperature sensors.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 46 Shipping 5 2012-10-01 2012-10-01 false Special requirement for temperature sensors. 153.565... Equipment Special Requirements § 153.565 Special requirement for temperature sensors. If a cargo listed in table 1 of this part refers to this section, temperature sensors must be used to monitor the cargo pump...

46 CFR 153.565 - Special requirement for temperature sensors.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 46 Shipping 5 2013-10-01 2013-10-01 false Special requirement for temperature sensors. 153.565... Equipment Special Requirements § 153.565 Special requirement for temperature sensors. If a cargo listed in table 1 of this part refers to this section, temperature sensors must be used to monitor the cargo pump...

46 CFR 153.565 - Special requirement for temperature sensors.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 46 Shipping 5 2014-10-01 2014-10-01 false Special requirement for temperature sensors. 153.565... Equipment Special Requirements § 153.565 Special requirement for temperature sensors. If a cargo listed in table 1 of this part refers to this section, temperature sensors must be used to monitor the cargo pump...

Characterization of AIRS temperature and water vapor measurement capability using correlative observations

NASA Technical Reports Server (NTRS)

Fetzer, Eric J.; Eldering, Annmarie; Lee, Sung-Yung

2005-01-01

In this presentation we address several fundamental issues in the measurement of temperature and water vapor by AIRS: accuracy, precision, vertical resolution and biases as a function of cloud amount. We use two correlative data sources. First we compare AIRS total water vapor with that from the Advanced microwave Sounding Radiometer for EOS (AMSR-E) instrument, also onboard the Aqua spacecraft. AMSRE uses a mature methodology with a heritage including the operational Special Sensor Microwave Imager (SSM/I) instruments. AIRS and AMSR-E observations are collocated and simultaneous, providing a very large data set for comparison: about 200,000 over-ocean matches daily. We show small cloud-dependent biases between AIRS and AMSR-E total water vapor for several oceanic regions. Our second correlative data source is several hundred dedicated radiosondes launched during AIRS overpasses.

State of the art in high-temperature fiber optic sensors

NASA Astrophysics Data System (ADS)

Fielder, Robert S.; Stinson-Bagby, Kelly L.; Palmer, Matthew E.

2004-12-01

The objective of the work presented was to develop a suite of sensors for use in high-temperature aerospace environments, including turbine engine monitoring, hypersonic vehicle skin friction measurements, and support ground and flight test operations. A fiber optic sensor platform was used to construct the sensor suite. Successful laboratory demonstrations include calibration of pressure sensors to 500psi at a gas temperature of 800°C. Additionally, pressure sensors were demonstrated at 800°C in combination with a high-speed (1.0MHz) fiber optic readout system enabling previously unobtainable dynamic measurements at high-temperatures. Temperature sensors have been field tested up to 1400°C and as low as -195°C. The key advancement that enabled the operation of these novel harsh environment sensors was a fiber optic packaging methodology that allowed the coupling of alumina and sapphire transducer components, optical fiber, and high-temperature alloy housing materials. The basic operation of the sensors and early experimental results are presented. Each of the sensors described here represent a quantifiable advancement in the state of the art in high-temperature physical sensors and will have a significant impact on the aerospace propulsion instrumentation industry.

Comparative Study of Two Different TiO2 Film Sensors on Response to H2 under UV Light and Room Temperature

PubMed Central

Peng, Xiaoying; Wang, Zhongming; Huang, Pan; Chen, Xun; Fu, Xianzhi; Dai, Wenxin

2016-01-01

An anatase TiO2 film sensor was prepared by a facile in-situ method on the interdigitated Au electrode deposited on the alumina substrate. The structure, morphology and the optical properties of the in-situ TiO2 film sensor were characterized by X-ray diffraction, Scanning Electron Microscopy, and UV-vis diffuse reflectance spectra. The photo-assisted gas sensitivities of the prepared film towards H2 gas were evaluated at room temperature in N2 and synthetic air atmospheres. As compared to TiO2 film sensor prepared by drop-coating method, this in-situ TiO2 film sensor exhibited a more compact structure composed of uniform TiO2 microspheres as well as a better gas sensitivity towards H2 under UV irradiation, especially in synthetic air. The photo-electrochemical measurements suggest that these improvements may be associated with the efficient charge transfer in the TiO2 interface induced by the TiO2 microsphere structure. This study might offer a feasible approach to develop photo-assisted gas sensors at ambient temperature. PMID:27509502

Temperature Measurement and Damage Detection in Concrete Beams Exposed to Fire Using PPP-BOTDA Based Fiber Optic Sensors.

PubMed

Bao, Yi; Hoehler, Matthew S; Smith, Christopher M; Bundy, Matthew; Chen, Genda

2017-10-01

In this study, distributed fiber optic sensors based on pulse pre-pump Brillouin optical time domain analysis (PPP-BODTA) are characterized and deployed to measure spatially-distributed temperatures in reinforced concrete specimens exposed to fire. Four beams were tested to failure in a natural gas fueled compartment fire, each instrumented with one fused silica, single-mode optical fiber as a distributed sensor and four thermocouples. Prior to concrete cracking, the distributed temperature was validated at locations of the thermocouples by a relative difference of less than 9 %. The cracks in concrete can be identified as sharp peaks in the temperature distribution since the cracks are locally filled with hot air. Concrete cracking did not affect the sensitivity of the distributed sensor but concrete spalling broke the optical fiber loop required for PPP-BOTDA measurements.

Long-term, high frequency in situ measurements of intertidal mussel bed temperatures using biomimetic sensors

PubMed Central

Helmuth, Brian; Choi, Francis; Matzelle, Allison; Torossian, Jessica L.; Morello, Scott L.; Mislan, K.A.S.; Yamane, Lauren; Strickland, Denise; Szathmary, P. Lauren; Gilman, Sarah E.; Tockstein, Alyson; Hilbish, Thomas J.; Burrows, Michael T.; Power, Anne Marie; Gosling, Elizabeth; Mieszkowska, Nova; Harley, Christopher D.G.; Nishizaki, Michael; Carrington, Emily; Menge, Bruce; Petes, Laura; Foley, Melissa M.; Johnson, Angela; Poole, Megan; Noble, Mae M.; Richmond, Erin L.; Robart, Matt; Robinson, Jonathan; Sapp, Jerod; Sones, Jackie; Broitman, Bernardo R.; Denny, Mark W.; Mach, Katharine J.; Miller, Luke P.; O’Donnell, Michael; Ross, Philip; Hofmann, Gretchen E.; Zippay, Mackenzie; Blanchette, Carol; Macfarlan, J.A.; Carpizo-Ituarte, Eugenio; Ruttenberg, Benjamin; Peña Mejía, Carlos E.; McQuaid, Christopher D.; Lathlean, Justin; Monaco, Cristián J.; Nicastro, Katy R.; Zardi, Gerardo

2016-01-01

At a proximal level, the physiological impacts of global climate change on ectothermic organisms are manifest as changes in body temperatures. Especially for plants and animals exposed to direct solar radiation, body temperatures can be substantially different from air temperatures. We deployed biomimetic sensors that approximate the thermal characteristics of intertidal mussels at 71 sites worldwide, from 1998-present. Loggers recorded temperatures at 10–30 min intervals nearly continuously at multiple intertidal elevations. Comparisons against direct measurements of mussel tissue temperature indicated errors of ~2.0–2.5 °C, during daily fluctuations that often exceeded 15°–20 °C. Geographic patterns in thermal stress based on biomimetic logger measurements were generally far more complex than anticipated based only on ‘habitat-level’ measurements of air or sea surface temperature. This unique data set provides an opportunity to link physiological measurements with spatially- and temporally-explicit field observations of body temperature. PMID:27727238

Long-term, high frequency in situ measurements of intertidal mussel bed temperatures using biomimetic sensors

NASA Astrophysics Data System (ADS)

Helmuth, Brian; Choi, Francis; Matzelle, Allison; Torossian, Jessica L.; Morello, Scott L.; Mislan, K. A. S.; Yamane, Lauren; Strickland, Denise; Szathmary, P. Lauren; Gilman, Sarah E.; Tockstein, Alyson; Hilbish, Thomas J.; Burrows, Michael T.; Power, Anne Marie; Gosling, Elizabeth; Mieszkowska, Nova; Harley, Christopher D. G.; Nishizaki, Michael; Carrington, Emily; Menge, Bruce; Petes, Laura; Foley, Melissa M.; Johnson, Angela; Poole, Megan; Noble, Mae M.; Richmond, Erin L.; Robart, Matt; Robinson, Jonathan; Sapp, Jerod; Sones, Jackie; Broitman, Bernardo R.; Denny, Mark W.; Mach, Katharine J.; Miller, Luke P.; O'Donnell, Michael; Ross, Philip; Hofmann, Gretchen E.; Zippay, Mackenzie; Blanchette, Carol; Macfarlan, J. A.; Carpizo-Ituarte, Eugenio; Ruttenberg, Benjamin; Peña Mejía, Carlos E.; McQuaid, Christopher D.; Lathlean, Justin; Monaco, Cristián J.; Nicastro, Katy R.; Zardi, Gerardo

2016-10-01

At a proximal level, the physiological impacts of global climate change on ectothermic organisms are manifest as changes in body temperatures. Especially for plants and animals exposed to direct solar radiation, body temperatures can be substantially different from air temperatures. We deployed biomimetic sensors that approximate the thermal characteristics of intertidal mussels at 71 sites worldwide, from 1998-present. Loggers recorded temperatures at 10-30 min intervals nearly continuously at multiple intertidal elevations. Comparisons against direct measurements of mussel tissue temperature indicated errors of ~2.0-2.5 °C, during daily fluctuations that often exceeded 15°-20 °C. Geographic patterns in thermal stress based on biomimetic logger measurements were generally far more complex than anticipated based only on ‘habitat-level’ measurements of air or sea surface temperature. This unique data set provides an opportunity to link physiological measurements with spatially- and temporally-explicit field observations of body temperature.

Perceiving Nasal Patency through Mucosal Cooling Rather than Air Temperature or Nasal Resistance

PubMed Central

Zhao, Kai; Blacker, Kara; Luo, Yuehao; Bryant, Bruce; Jiang, Jianbo

2011-01-01

Adequate perception of nasal airflow (i.e., nasal patency) is an important consideration for patients with nasal sinus diseases. The perception of a lack of nasal patency becomes the primary symptom that drives these patients to seek medical treatment. However, clinical assessment of nasal patency remains a challenge because we lack objective measurements that correlate well with what patients perceive.The current study examined factors that may influence perceived patency, including air temperature, humidity, mucosal cooling, nasal resistance, and trigeminal sensitivity. Forty-four healthy subjects rated nasal patency while sampling air from three facial exposure boxes that were ventilated with untreated room air, cold air, and dry air, respectively. In all conditions, air temperature and relative humidity inside each box were recorded with sensors connected to a computer. Nasal resistance and minimum airway cross-sectional area (MCA) were measured using rhinomanometry and acoustic rhinometry, respectively. General trigeminal sensitivity was assessed through lateralization thresholds to butanol. No significant correlation was found between perceived patency and nasal resistance or MCA. In contrast, air temperature, humidity, and butanol threshold combined significantly contributed to the ratings of patency, with mucosal cooling (heat loss) being the most heavily weighted predictor. Air humidity significantly influences perceived patency, suggesting that mucosal cooling rather than air temperature alone provides the trigeminal sensation that results in perception of patency. The dynamic cooling between the airstream and the mucosal wall may be quantified experimentally or computationally and could potentially lead to a new clinical evaluation tool. PMID:22022361

Multifunctional potentiometric gas sensor array with an integrated temperature control and temperature sensors

DOEpatents

Blackburn, Bryan M; Wachsman, Eric D

2015-05-12

Embodiments of the subject invention relate to a gas sensor and method for sensing one or more gases. An embodiment incorporates an array of sensing electrodes maintained at similar or different temperatures, such that the sensitivity and species selectivity of the device can be fine tuned between different pairs of sensing electrodes. A specific embodiment pertains to a gas sensor array for monitoring combustion exhausts and/or chemical reaction byproducts. An embodiment of the subject device related to this invention operates at high temperatures and can withstand harsh chemical environments. Embodiments of the device are made on a single substrate. The devices can also be made on individual substrates and monitored individually as if they were part of an array on a single substrate. The device can incorporate sensing electrodes in the same environment, which allows the electrodes to be coplanar and, thus, keep manufacturing costs low. Embodiments of the device can provide improvements to sensitivity, selectivity, and signal interference via surface temperature control.

Development and Application of a Next Generation Air Sensor Network for the Hong Kong Marathon 2015 Air Quality Monitoring

PubMed Central

Sun, Li; Wong, Ka Chun; Wei, Peng; Ye, Sheng; Huang, Hao; Yang, Fenhuan; Westerdahl, Dane; Louie, Peter K.K.; Luk, Connie W.Y.; Ning, Zhi

2016-01-01

This study presents the development and evaluation of a next generation air monitoring system with both laboratory and field tests. A multi-parameter algorithm was used to correct for the impact of environmental conditions on the electrochemical sensors for carbon monoxide (CO) and nitrogen dioxide (NO2) pollutants. The field evaluation in an urban roadside environment in comparison to designated monitors showed good agreement with measurement error within 5% of the pollutant concentrations. Multiple sets of the developed system were then deployed in the Hong Kong Marathon 2015 forming a sensor-based network along the marathon route. Real-time air pollution concentration data were wirelessly transmitted and the Air Quality Health Index (AQHI) for the Green Marathon was calculated, which were broadcast to the public on an hourly basis. The route-specific sensor network showed somewhat different pollutant patterns than routine air monitoring, indicating the immediate impact of traffic control during the marathon on the roadside air quality. The study is one of the first applications of a next generation sensor network in international sport events, and it demonstrated the usefulness of the emerging sensor-based air monitoring technology in rapid network deployment to supplement existing air monitoring. PMID:26861336

Polymer substrate temperature sensor array for brain interfaces.

PubMed

Kim, Insoo; Fok, Ho Him R; Li, Yuanyuan; Jackson, Thomas N; Gluckman, Bruce J

2011-01-01

We developed an implantable thin film transistor temperature sensor (TFT-TS) to measure temperature changes in the brain. These changes are assumed to be associated with cerebral metabolism and neuronal activity. Two prototype TFT-TSs were designed and tested in-vitro: one with 8 diode-connected single-ended sensors, and the other with 4 pairs of differential-ended sensors in an array configuration. The sensor elements are 25 ~ 100 pm in width and 5 μm in length. The TFT-TSs were fabricated based on high-speed ZnO TFT process technology on flexible polyimide substrates (50 μm thick, 500 μm width, 20 mm length). In order to interface external signal electronics, they were directly bonded to a prototype printed circuit board using anisotropic conductive films The prototypes were characterized between 23 ~ 38 °C using a commercial temperature sensor and custom-designed temperature controlled oven. The maximum sensitivity of 40 mV/°C was obtained from the TFT-TS.

Research on Vehicle Temperature Regulation System Based on Air Convection Principle

NASA Astrophysics Data System (ADS)

Zhuge, Muzi; Li, Xiang; Liang, Caifeng

2018-03-01

The long time parking outdoors in the summer will lead to too high temperature in the car, and the harmful gas produced by the vehicle engine will stay in the confined space for a long time during the parking process, which will do great harm to the human body. If the air conditioning system is turned on before driving, the cooling rate is slow and the battery loss is large. To solve the above problems, we designed a temperature adjusting system based on the principle of air convection. We can choose the automatic mode or manual mode to achieve control of a convection window. In the automatic mode, the system will automatically detect the environmental temperature, through the sensor to complete the detection, and the signal is transmitted to the microcontroller to control the window open or close, in manual mode, the remote control of the window can be realized by Bluetooth. Therefore, the system has important practical significance to effectively regulate temperature, prolong battery life, and improve the safety and comfort of traffic vehicles.

Integrated LTCC pressure/flow/temperature multisensor for compressed air diagnostics.

PubMed

Fournier, Yannick; Maeder, Thomas; Boutinard-Rouelle, Grégoire; Barras, Aurélie; Craquelin, Nicolas; Ryser, Peter

2010-01-01

We present a multisensor designed for industrial compressed air diagnostics and combining the measurement of pressure, flow, and temperature, integrated with the corresponding signal conditioning electronics in a single low-temperature co-fired ceramic (LTCC) package. The developed sensor may be soldered onto an integrated electro-fluidic platform by using standard surface mount device (SMD) technology, e.g., as a standard electronic component would be on a printed circuit board, obviating the need for both wires and tubes and thus paving the road towards low-cost integrated electro-fluidic systems. Several performance aspects of this device are presented and discussed, together with electronics design issues.

Integrated LTCC Pressure/Flow/Temperature Multisensor for Compressed Air Diagnostics†

PubMed Central

Fournier, Yannick; Maeder, Thomas; Boutinard-Rouelle, Grégoire; Barras, Aurélie; Craquelin, Nicolas; Ryser, Peter

2010-01-01

We present a multisensor designed for industrial compressed air diagnostics and combining the measurement of pressure, flow, and temperature, integrated with the corresponding signal conditioning electronics in a single low-temperature co-fired ceramic (LTCC) package. The developed sensor may be soldered onto an integrated electro-fluidic platform by using standard surface mount device (SMD) technology, e.g., as a standard electronic component would be on a printed circuit board, obviating the need for both wires and tubes and thus paving the road towards low-cost integrated electro-fluidic systems. Several performance aspects of this device are presented and discussed, together with electronics design issues. PMID:22163518

Automated general temperature correction method for dielectric soil moisture sensors

NASA Astrophysics Data System (ADS)

Kapilaratne, R. G. C. Jeewantinie; Lu, Minjiao

2017-08-01

An effective temperature correction method for dielectric sensors is important to ensure the accuracy of soil water content (SWC) measurements of local to regional-scale soil moisture monitoring networks. These networks are extensively using highly temperature sensitive dielectric sensors due to their low cost, ease of use and less power consumption. Yet there is no general temperature correction method for dielectric sensors, instead sensor or site dependent correction algorithms are employed. Such methods become ineffective at soil moisture monitoring networks with different sensor setups and those that cover diverse climatic conditions and soil types. This study attempted to develop a general temperature correction method for dielectric sensors which can be commonly used regardless of the differences in sensor type, climatic conditions and soil type without rainfall data. In this work an automated general temperature correction method was developed by adopting previously developed temperature correction algorithms using time domain reflectometry (TDR) measurements to ThetaProbe ML2X, Stevens Hydra probe II and Decagon Devices EC-TM sensor measurements. The rainy day effects removal procedure from SWC data was automated by incorporating a statistical inference technique with temperature correction algorithms. The temperature correction method was evaluated using 34 stations from the International Soil Moisture Monitoring Network and another nine stations from a local soil moisture monitoring network in Mongolia. Soil moisture monitoring networks used in this study cover four major climates and six major soil types. Results indicated that the automated temperature correction algorithms developed in this study can eliminate temperature effects from dielectric sensor measurements successfully even without on-site rainfall data. Furthermore, it has been found that actual daily average of SWC has been changed due to temperature effects of dielectric sensors with a

High Lapse Rates in AIRS Retrieved Temperatures in Cold Air Outbreaks

NASA Technical Reports Server (NTRS)

Fetzer, Eric J.; Kahn, Brian; Olsen, Edward T.; Fishbein, Evan

2004-01-01

The Atmospheric Infrared Sounder (AIRS) experiment, on NASA's Aqua spacecraft, uses a combination of infrared and microwave observations to retrieve cloud and surface properties, plus temperature and water vapor profiles comparable to radiosondes throughout the troposphere, for cloud cover up to 70%. The high spectral resolution of AIRS provides sensitivity to important information about the near-surface atmosphere and underlying surface. A preliminary analysis of AIRS temperature retrievals taken during January 2003 reveals extensive areas of superadiabatic lapse rates in the lowest kilometer of the atmosphere. These areas are found predominantly east of North America over the Gulf Stream, and, off East Asia over the Kuroshio Current. Accompanying the high lapse rates are low air temperatures, large sea-air temperature differences, and low relative humidities. Imagery from a Visible / Near Infrared instrument on the AIRS experiment shows accompanying clouds. These lines of evidence all point to shallow convection in the bottom layer of a cold air mass overlying warm water, with overturning driven by heat flow from ocean to atmosphere. An examination of operational radiosondes at six coastal stations in Japan shows AIRS to be oversensitive to lower tropospheric lapse rates due to systematically warm near-surface air temperatures. The bias in near-surface air temperature is seen to be independent of sea surface temperature, however. AIRS is therefore sensitive to air-sea temperature difference, but with a warm atmospheric bias. A regression fit to radiosondes is used to correct AIRS near-surface retrieved temperatures, and thereby obtain an estimate of the true atmosphere-ocean thermal contrast in five subtropical regions across the north Pacific. Moving eastward, we show a systematic shift in this air-sea temperature differences toward more isothermal conditions. These results, while preliminary, have implications for our understanding of heat flow from ocean to

A catheter-type flow sensor for measurement of aspirated- and inspired-air characteristics in the bronchial region

NASA Astrophysics Data System (ADS)

Shikida, M.; Naito, J.; Yokota, T.; Kawabe, T.; Hayashi, Y.; Sato, K.

2009-10-01

We developed a novel catheter-type flow sensor for measuring the aspirated- and inspired-air characteristics trans-bronchially. An on-wall in-tube thermal flow sensor is mounted inside the tube, and it is used as a measurement tool in a bronchoscope. The external diameter of the tube is less than a few mm, and therefore, it can evaluate the flow characteristics in the small bronchial region. We newly developed a fabrication process to miniaturize it to less than 2.0 mm in the external diameter by using a heat shrinkable tube. A film sensor fabricated by photolithography was inserted into the tube by hand. By applying a heat shrinking process, the film was automatically mounted on the inner wall surface, and the outer size of the tube was miniaturized to almost half its original size. The final inner and outer diameters of the tube were 1.0 mm and 1.8 mm, respectively. The relationship between the input power of the sensor and the flow rate obeyed King's equation in both forward and reverse flow conditions. The sensor output dependence on ambient temperature was also studied, and the curve obtained at 39.2 °C was used as the calibration curve in animal experiments. The sensor characteristics under reciprocating flow were studied by using a ventilator, and we confirmed that the sensor was able to measure the reciprocating flow at 2.0 Hz. Finally, we successfully measured the aspirated- and inspired-air characteristics in the air passage of a rat.

A Temperature Sensor using a Silicon-on-Insulator (SOI) Timer for Very Wide Temperature Measurement

NASA Technical Reports Server (NTRS)

Patterson, Richard L.; Hammoud, Ahmad; Elbuluk, Malik; Culley, Dennis E.

2008-01-01

A temperature sensor based on a commercial-off-the-shelf (COTS) Silicon-on-Insulator (SOI) Timer was designed for extreme temperature applications. The sensor can operate under a wide temperature range from hot jet engine compartments to cryogenic space exploration missions. For example, in Jet Engine Distributed Control Architecture, the sensor must be able to operate at temperatures exceeding 150 C. For space missions, extremely low cryogenic temperatures need to be measured. The output of the sensor, which consisted of a stream of digitized pulses whose period was proportional to the sensed temperature, can be interfaced with a controller or a computer. The data acquisition system would then give a direct readout of the temperature through the use of a look-up table, a built-in algorithm, or a mathematical model. Because of the wide range of temperature measurement and because the sensor is made of carefully selected COTS parts, this work is directly applicable to the NASA Fundamental Aeronautics/Subsonic Fixed Wing Program--Jet Engine Distributed Engine Control Task and to the NASA Electronic Parts and Packaging (NEPP) Program. In the past, a temperature sensor was designed and built using an SOI operational amplifier, and a report was issued. This work used an SOI 555 timer as its core and is completely new work.

Performance Evaluation of "Low-cost" Sensors for Measuring Gaseous and Particle Air Pollutants: Results from Two Years of Field and Laboratory Testing

NASA Astrophysics Data System (ADS)

Feenstra, B. J.; Polidori, A.; Tisopulos, L.; Papapostolou, V.; Zhang, H.; Pathmanabhan, J.

2016-12-01

In recent years great progress has been made in development of low-cost miniature air quality sensing technologies. Such low-cost sensors offer a prospect of providing a real-time spatially dense information on pollutants, however, the quality of the data produced by these sensors is so far untested. In an effort to inform the general public about the actual performance of commercially available low-cost air quality sensors, in June 2014 the South Coast Air Quality Management District (SCAQMD) has established the Air Quality Sensor Performance Evaluation Center (AQ-SPEC). This program performs a thorough characterization of low-cost sensors under ambient (in the field) and controlled (in the laboratory) conditions. During the field testing, air quality sensors are operated side-by-side with Federal Reference Methods and Federal Equivalent Methods (FRM and FEM, respectively), which are routinely used to measure the ambient concentration of gaseous or particle pollutants for regulatory purposes. Field testing is conducted at two of SCAQMD's existing air monitoring stations, one in Rubidoux and one near the I-710 freeway. Sensors that demonstrate an acceptable performance in the field are brought back to the lab where a "characterization chamber" is used to challenge these devices with known concentrations of different particle and gaseous pollutants under different temperature and relative humidity levels. Testing results for each sensor are then summarized in a technical report and, along with other relevant information, posted online on a dedicated website (www.aqmd.gov/aq-spec) to educate the public about the capabilities of commercially available sensors and their potential applications. During this presentation, the results from two years of field and laboratory testing will be presented. The major strengths and weaknesses of some of the most commonly available particle and gaseous sensors will be discussed.

Wide-Range Temperature Sensors with High-Level Pulse Train Output

NASA Technical Reports Server (NTRS)

Hammoud, Ahmad; Patterson, Richard L.

2009-01-01

Two types of temperature sensors have been developed for wide-range temperature applications. The two sensors measure temperature in the range of -190 to +200 C and utilize a thin-film platinum RTD (resistance temperature detector) as the temperature-sensing element. Other parts used in the fabrication of these sensors include NPO (negative-positive- zero) type ceramic capacitors for timing, thermally-stable film or wirewound resistors, and high-temperature circuit boards and solder. The first type of temperature sensor is a relaxation oscillator circuit using an SOI (silicon-on-insulator) operational amplifier as a comparator. The output is a pulse train with a period that is roughly proportional to the temperature being measured. The voltage level of the pulse train is high-level, for example 10 V. The high-level output makes the sensor less sensitive to noise or electromagnetic interference. The output can be read by a frequency or period meter and then converted into a temperature reading. The second type of temperature sensor is made up of various types of multivibrator circuits using an SOI type 555 timer and the passive components mentioned above. Three configurations have been developed that were based on the technique of charging and discharging a capacitor through a resistive element to create a train of pulses governed by the capacitor-resistor time constant. Both types of sensors, which operated successfully over the wide temperature range, have potential use in extreme temperature environments including jet engines and space exploration missions.

Air temperature recordings in infant incubators.

PubMed Central

Aynsley-Green, A; Roberton, N R; Rolfe, P

1975-01-01

Air temperatures were continuously recorded inside four incubators with proportional heating control and six incubators with on/off heating cycles, during routine use. The air temperatures in the former were constant throughout, with a gradient between the roof and above-mattress air temperature not exceeding 1 degree C. In contrast, the recordings from the latter models showed a regular cyclical oscillation, the duration of the cycle varying from 14 to 44 minutes. Each incubator had a characteristic profile. The roof air temperature could vary by as much as 7-1 degrees C and the above-mattress air temperature by as much as 2-6 degrees C during the cycle. The oscillation persisted in the air temperatures recorded inside an open-ended hemicylindrical heat shield when used inside these incubators, but was markedly reduced inside a closed-ended heat shield, Carbon dioxide concentration did not increase significantly inside the latter. Images FIG. 1 FIG. 2 PMID:1147654

Evaluating the performance of low cost chemical sensors for air pollution research.

PubMed

Lewis, Alastair C; Lee, James D; Edwards, Peter M; Shaw, Marvin D; Evans, Mat J; Moller, Sarah J; Smith, Katie R; Buckley, Jack W; Ellis, Matthew; Gillot, Stefan R; White, Andrew

2016-07-18

Low cost pollution sensors have been widely publicized, in principle offering increased information on the distribution of air pollution and a democratization of air quality measurements to amateur users. We report a laboratory study of commonly-used electrochemical sensors and quantify a number of cross-interferences with other atmospheric chemicals, some of which become significant at typical suburban air pollution concentrations. We highlight that artefact signals from co-sampled pollutants such as CO2 can be greater than the electrochemical sensor signal generated by the measurand. We subsequently tested in ambient air, over a period of three weeks, twenty identical commercial sensor packages alongside standard measurements and report on the degree of agreement between references and sensors. We then explore potential experimental approaches to improve sensor performance, enhancing outputs from qualitative to quantitative, focusing on low cost VOC photoionization sensors. Careful signal handling, for example, was seen to improve limits of detection by one order of magnitude. The quantity, magnitude and complexity of analytical interferences that must be characterised to convert a signal into a quantitative observation, with known uncertainties, make standard individual parameter regression inappropriate. We show that one potential solution to this problem is the application of supervised machine learning approaches such as boosted regression trees and Gaussian processes emulation.

Fiber Optic Sensors for Structural Health Monitoring of Air Platforms

PubMed Central

Guo, Honglei; Xiao, Gaozhi; Mrad, Nezih; Yao, Jianping

2011-01-01

Aircraft operators are faced with increasing requirements to extend the service life of air platforms beyond their designed life cycles, resulting in heavy maintenance and inspection burdens as well as economic pressure. Structural health monitoring (SHM) based on advanced sensor technology is potentially a cost-effective approach to meet operational requirements, and to reduce maintenance costs. Fiber optic sensor technology is being developed to provide existing and future aircrafts with SHM capability due to its unique superior characteristics. This review paper covers the aerospace SHM requirements and an overview of the fiber optic sensor technologies. In particular, fiber Bragg grating (FBG) sensor technology is evaluated as the most promising tool for load monitoring and damage detection, the two critical SHM aspects of air platforms. At last, recommendations on the implementation and integration of FBG sensors into an SHM system are provided. PMID:22163816

Development of a TDLAS sensor for temperature and concentration of H2 O in high speed and high temperature flows

NASA Astrophysics Data System (ADS)

Sheehe, Suzanne; O'Byrne, Sean

2017-06-01

The development of a sensor for simultaneous temperature concentration of H2 O and temperature in high speed flows is presented. H2 O is a desirable target sensing species because it is a primary product in combustion systems; both temperature and concentration profiles can be used to assess both the extent of the combustion and the flow field characteristics. Accurate measurements are therefore highly desirable. The sensor uses a vertical-cavity surface emitting laser (VCSEL) scanned at 50 kHz from 7172 to 7186 cm-1. Temperatures and concentrations are extracted from the spectra by fitting theoretical spectra to the experimental data. The theoretical spectra are generated using GENSPECT in conjunction with line parameters from the HITRAN 2012 database. To validate the theoretical spectra, experimental spectra of H2 O were obtained at known temperatures (290-550 K) and pressures (30 torr) in a heated static gas cell. The results show that some theoretical lines deviate from the experimental lines. New line-strengths are calculated assuming that the line assignments and broadening parameters in HITRAN are correct. This data is essential for accurate H2 O concentration and temperature measurements at low pressure and high temperature conditions. US Air Force Asian Office of Aerospace Research and Development Grant FA2386-16-1-4092.

Fiber optic photoelastic pressure sensor for high temperature gases

NASA Technical Reports Server (NTRS)

Wesson, Laurence N.; Redner, Alex S.; Baumbick, Robert J.

1990-01-01

A novel fiber optic pressure sensor based on the photoelastic effects has been developed for extremely high temperature gases. At temperatures varying from 25 to 650 C, the sensor experiences no change in the peak pressure of the transfer function and only a 10 percent drop in dynamic range. Refinement of the sensor has resulted in an optoelectronic interface and processor software which can calculate pressure values within 1 percent of full scale at any temperature within the full calibrated temperature range.

Geographically distributed environmental sensor system

DOEpatents

French, Patrick; Veatch, Brad; O'Connor, Mike

2006-10-03

The present invention is directed to a sensor network that includes a number of sensor units and a base unit. The base station operates in a network discovery mode (in which network topology information is collected) in a data polling mode (in which sensed information is collected from selected sensory units). Each of the sensor units can include a number of features, including an anemometer, a rain gauge, a compass, a GPS receiver, a barometric pressure sensor, an air temperature sensor, a humidity sensor, a level, and a radiant temperature sensor.

Community Air Sensor Network (CAIRSENSE) Project: Lower Cost, Continuous Ambient Monitoring Methods

EPA Science Inventory

Advances in air pollution sensor technology have enabled the development of small and low cost systems to measure outdoor air pollution. The deployment of numerous sensors across a small geographic area would have potential benefits to supplement existing monitoring networks and ...

High-sensitivity in situ QCLAS-based ammonia concentration sensor for high-temperature applications

NASA Astrophysics Data System (ADS)

Peng, W. Y.; Sur, R.; Strand, C. L.; Spearrin, R. M.; Jeffries, J. B.; Hanson, R. K.

2016-07-01

A novel quantum cascade laser (QCL) absorption sensor is presented for high-sensitivity in situ measurements of ammonia (hbox {NH}_3) in high-temperature environments, using scanned wavelength modulation spectroscopy (WMS) with first-harmonic-normalized second-harmonic detection (scanned WMS-2 f/1 f) to neutralize the effect of non-absorption losses in the harsh environment. The sensor utilized the sQ(9,9) transition of the fundamental symmetric stretch band of hbox {NH}_3 at 10.39 {\\upmu }hbox {m} and was sinusoidally modulated at 10 kHz and scanned across the peak of the absorption feature at 50 Hz, leading to a detection bandwidth of 100 Hz. A novel technique was used to select an optimal WMS modulation depth parameter that reduced the sensor's sensitivity to spectral interference from hbox {H}_2hbox {O} and hbox {CO}_2 without significantly sacrificing signal-to-noise ratio. The sensor performance was validated by measuring known concentrations of hbox {NH}_3 in a flowing gas cell. The sensor was then demonstrated in a laboratory-scale methane-air burner seeded with hbox {NH}_3, achieving a demonstrated detection limit of 2.8 ± 0.26 ppm hbox {NH}_3 by mole at a path length of 179 cm, equivalence ratio of 0.6, pressure of 1 atm, and temperatures of up to 600 K.

Improved Optical-Fiber Temperature Sensors

NASA Technical Reports Server (NTRS)

Rogowski, Robert S.; Egalon, Claudio O.

1993-01-01

In optical-fiber temperature sensors of proposed type, phosphorescence and/or fluorescence in temperature-dependent coating layers coupled to photodetectors. Phosphorescent and/or fluorescent behavior(s) of coating material(s) depend on temperature; coating material or mixture of materials selected so one can deduce temperature from known temperature dependence of phosphorescence and/or fluorescence spectrum, and/or characteristic decay of fluorescence. Basic optical configuration same as that of optical-fiber chemical detectors described in "Making Optical-Fiber Chemical Detectors More Sensitive" (LAR-14525).

Evaluation of Fiber Bragg Grating and Distributed Optical Fiber Temperature Sensors

DOE Office of Scientific and Technical Information (OSTI.GOV)

McCary, Kelly Marie

Fiber optic temperature sensors were evaluated in the High Temperature Test Lab (HTTL) to determine the accuracy of the measurements at various temperatures. A distributed temperature sensor was evaluated up to 550C and a fiber Bragg grating sensor was evaluated up to 750C. HTTL measurements indicate that there is a drift in fiber Bragg sensor over time of approximately -10C with higher accuracy at temperatures above 300C. The distributed sensor produced some bad data points at and above 500C but produced measurements with less than 2% error at increasing temperatures up to 400C

Thin-film fiber optic hydrogen and temperature sensor system

DOEpatents

Nave, Stanley E.

1998-01-01

The invention discloses a sensor probe device for monitoring of hydrogen gas concentrations and temperatures by the same sensor probe. The sensor probe is constructed using thin-film deposition methods for the placement of a multitude of layers of materials sensitive to hydrogen concentrations and temperature on the end of a light transparent lens located within the sensor probe. The end of the lens within the sensor probe contains a lens containing a layer of hydrogen permeable material which excludes other reactive gases, a layer of reflective metal material that forms a metal hydride upon absorbing hydrogen, and a layer of semi-conducting solid that is transparent above a temperature dependent minimum wavelength for temperature detection. The three layers of materials are located at the distal end of the lens located within the sensor probe. The lens focuses light generated by broad-band light generator and connected by fiber-optics to the sensor probe, onto a reflective metal material layer, which passes through the semi-conducting solid layer, onto two optical fibers located at the base of the sensor probe. The reflected light is transmitted over fiberoptic cables to a spectrometer and system controller. The absence of electrical signals and electrical wires in the sensor probe provides for an elimination of the potential for spark sources when monitoring in hydrogen rich environments, and provides a sensor free from electrical interferences.

Village Green Project and Air Sensor Kits

EPA Science Inventory

This is a presentation for the OAQPS Teachers Workshop. Will provide a background overview on the Village Green Project and our air sensor kit for outreach, then have the teachers try putting it together.

Pyroelectric Ceramics as Temperature Sensors for Energy System Applications

NASA Astrophysics Data System (ADS)

Silva, Jorge Luis

Temperature is continuously monitored in energy systems to ensure safe operation temperatures, increase efficiency and avoid high emissions. Most of energy systems operate at high temperature and harsh environments to achieve higher efficiencies, therefore temperature sensing devices that can operate under these conditions are highly desired. The interest has increased in temperature sensors capable to operate and in harsh environments and temperature sensors capable to transmit thermal information wirelessly. One of the solutions for developing harsh environment sensors is to use ceramic materials, especially functional ceramics such as pyroelectrics. Pyroelectric ceramics could be used to develop active sensors for both temperature and pressure due to their capabilities in coupling energy among mechanical, thermal, and electrical domains. In this study, two different pyroelectric materials were used to develop two different temperature sensors systems. First, a high temperature sensor was developed using a lithium niobate (LiNbO3) pyroelectric ceramic. With its Curie temperature of 1210 °C, lithium niobate is capable to maintain its pyroelectric properties at high temperature making it ideal for temperature sensing at high temperature applications. Lithium niobate has been studied previously in the attempt to use its pyroelectric current as the sensing mechanism to measure temperatures up to 500 °C. Pyroelectric coefficient of lithium niobate is a function of temperature as reported in a previous study, therefore a dynamic technique is utilized to measure the pyroelectric coefficient of the lithium niobate used in this study. The pyroelectric coefficient was successfully measured up to 500 °C with coefficients ranging from -8.5 x 10 -5 C/m2 °C at room temperature to -23.70 x 10 -5 C/m2 °C at 500 °C. The lithium niobate sensor was then tested at higher temperatures: 220 °C, 280 °C, 410 °C and 500 °C with 4.31 %, 2.1 %, 0.4 % and 0.6 % deviation

The Evolution of High Temperature Gas Sensors.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Garzon, F. H.; Brosha, E. L.; Mukundan, R.

2001-01-01

Gas sensor technology based on high temperature solid electrolytes is maturing rapidly. Recent advances in metal oxide catalysis and thin film materials science has enabled the design of new electrochemical sensors. We have demonstrated prototype amperometric oxygen sensors, nernstian potentiometric oxygen sensors that operate in high sulfur environments, and hydrocarbon and carbon monoxide sensing mixed potentials sensors. Many of these devices exhibit part per million sensitivities, response times on the order of seconds and excellent long-term stability.

40 CFR 1065.215 - Pressure transducers, temperature sensors, and dewpoint sensors.

Code of Federal Regulations, 2014 CFR

2014-07-01

... sensors, such as resistive temperature detectors (RTDs). (d) Pressure. Pressure transducers must be... chilled-surface hygrometers, which include chilled mirror detectors and chilled surface acoustic wave (SAW) detectors. For other applications, we recommend thin-film capacitance sensors. You may use other dewpoint...

40 CFR 1065.215 - Pressure transducers, temperature sensors, and dewpoint sensors.

Code of Federal Regulations, 2013 CFR

2013-07-01

... sensors, such as resistive temperature detectors (RTDs). (d) Pressure. Pressure transducers must be... chilled-surface hygrometers, which include chilled mirror detectors and chilled surface acoustic wave (SAW) detectors. For other applications, we recommend thin-film capacitance sensors. You may use other dewpoint...

40 CFR 1065.215 - Pressure transducers, temperature sensors, and dewpoint sensors.

Code of Federal Regulations, 2011 CFR

2011-07-01

... sensors, such as resistive temperature detectors (RTDs). (d) Pressure. Pressure transducers must be... chilled-surface hygrometers, which include chilled mirror detectors and chilled surface acoustic wave (SAW) detectors. For other applications, we recommend thin-film capacitance sensors. You may use other dewpoint...

40 CFR 1065.215 - Pressure transducers, temperature sensors, and dewpoint sensors.

Code of Federal Regulations, 2012 CFR

2012-07-01

... sensors, such as resistive temperature detectors (RTDs). (d) Pressure. Pressure transducers must be... chilled-surface hygrometers, which include chilled mirror detectors and chilled surface acoustic wave (SAW) detectors. For other applications, we recommend thin-film capacitance sensors. You may use other dewpoint...

High-temperature optical fiber sensors for characterization of advanced composite aerospace materials

NASA Astrophysics Data System (ADS)

Wavering, Thomas A.; Greene, Jonathan A.; Meller, Scott A.; Bailey, Timothy A.; Kozikowski, Carrie L.; Lenahan, Shannon M.; Murphy, Kent A.; Camden, Michael P.; Simmons, Larry W.

1999-01-01

Optical fiber sensors have numerous advantages over conventional sensing technologies. One such advantage is that optical fiber sensors can operate in high temperature environments. While most conventional electrical-based sensors do not operate reliably over 300 degrees C, fused silica based optical fiber sensors can survive up to 900 degrees C, and sapphire based optical fiber sensors can survive up to 2000 degrees C. Using both fused silica and sapphire technologies, we present result for high temperature strain, pressure, and temperature sensors using Extrinsic Fabry-Perot INterferometric-based and Bragg grating sensors. High temperature strain and temperature sensors were used to conduct fatigue testing of composite coupons at 600 degrees C. The results from these specific high temperature applications are presented along with future applications and directions for these sensors.

Encapsulation for smart textile electronics - humidity and temperature sensor.

PubMed

Larsson, Andreas; Tran, Thanh-Nam; Aasmundtveit, Knut E; Seeberg, Trine M

2015-01-01

A combined humidity and temperature sensor was packaged by vacuum casting onto three different types of textiles; cotton, nylon and a waterproof fabric. This was done in order to integrate the sensor in a jacket in a soft and reliable way without changing the sensor performance. A membrane was custom made and integrated into the device to protect the sensor from the environment. The packaged sensors performance was characterized in a climate chamber were the relative humidity and temperature ranged from 25 % to 95 % and -10 °C to 75 °C respectively. The packaged sensors showed insignificant to limited performance degradation.

Recent Improvements in Retrieving Near-Surface Air Temperature and Humidity Using Microwave Remote Sensing

NASA Technical Reports Server (NTRS)

Roberts, J. Brent

2010-01-01

Detailed studies of the energy and water cycles require accurate estimation of the turbulent fluxes of moisture and heat across the atmosphere-ocean interface at regional to basin scale. Providing estimates of these latent and sensible heat fluxes over the global ocean necessitates the use of satellite or reanalysis-based estimates of near surface variables. Recent studies have shown that errors in the surface (10 meter)estimates of humidity and temperature are currently the largest sources of uncertainty in the production of turbulent fluxes from satellite observations. Therefore, emphasis has been placed on reducing the systematic errors in the retrieval of these parameters from microwave radiometers. This study discusses recent improvements in the retrieval of air temperature and humidity through improvements in the choice of algorithms (linear vs. nonlinear) and the choice of microwave sensors. Particular focus is placed on improvements using a neural network approach with a single sensor (Special Sensor Microwave/Imager) and the use of combined sensors from the NASA AQUA satellite platform. The latter algorithm utilizes the unique sampling available on AQUA from the Advanced Microwave Scanning Radiometer (AMSR-E) and the Advanced Microwave Sounding Unit (AMSU-A). Current estimates of uncertainty in the near-surface humidity and temperature from single and multi-sensor approaches are discussed and used to estimate errors in the turbulent fluxes.

In situ measurement of the junction temperature of light emitting diodes using a flexible micro temperature sensor.

PubMed

Lee, Chi-Yuan; Su, Ay; Liu, Yin-Chieh; Fan, Wei-Yuan; Hsieh, Wei-Jung

2009-01-01

This investigation aimed to fabricate a flexible micro resistive temperature sensor to measure the junction temperature of a light emitting diode (LED). The junction temperature is typically measured using a thermal resistance measurement approach. This approach is limited in that no standard regulates the timing of data capture. This work presents a micro temperature sensor that can measure temperature stably and continuously, and has the advantages of being lightweight and able to monitor junction temperatures in real time. Micro-electro-mechanical-systems (MEMS) technologies are employed to minimize the size of a temperature sensor that is constructed on a stainless steel foil substrate (SS-304 with 30 μm thickness). A flexible micro resistive temperature sensor can be fixed between the LED chip and the frame. The junction temperature of the LED can be measured from the linear relationship between the temperature and the resistance. The sensitivity of the micro temperature sensor is 0.059 ± 0.004 Ω/°C. The temperature of the commercial CREE(®) EZ1000 chip is 119.97 °C when it is thermally stable, as measured using the micro temperature sensor; however, it was 126.9 °C, when measured by thermal resistance measurement. The micro temperature sensor can be used to replace thermal resistance measurement and performs reliably.

Cryogenic fiber optic temperature sensor and method of manufacturing the same

NASA Technical Reports Server (NTRS)

Kochergin, Vladimir (Inventor)

2012-01-01

This invention teaches the fiber optic sensors temperature sensors for cryogenic temperature range with improved sensitivity and resolution, and method of making said sensors. In more detail, the present invention is related to enhancement of temperature sensitivity of fiber optic temperature sensors at cryogenic temperatures by utilizing nanomaterials with a thermal expansion coefficient that is smaller than the thermal expansion coefficient of the optical fiber but larger in absolute value than the thermal expansion coefficient of the optical fiber at least over a range of temperatures.

Controlled-Temperature Hot-Air Gun

NASA Technical Reports Server (NTRS)

Munoz, M. C.

1986-01-01

Materials that find applications in wind tunnels first tested in laboratory. Hot-Air Gun differs from commercial units in that flow rate and temperature monitored and controlled. With typical compressed-airsupply pressure of 25 to 38 psi (170 to 260 kPa), flow rate and maximum temperature are 34 stdft3/min (0.96 stdm3/min) and 1,090 degrees F (590 degrees C), respectively. Resembling elaborate but carefully regulated hot-air gun, setup used to apply blasts of air temperatures above 1,500 degrees F (815 degrees C) to test specimens.

Thin-film fiber optic hydrogen and temperature sensor system

DOEpatents

Nave, S.E.

1998-07-21

The invention discloses a sensor probe device for monitoring of hydrogen gas concentrations and temperatures by the same sensor probe. The sensor probe is constructed using thin-film deposition methods for the placement of a multitude of layers of materials sensitive to hydrogen concentrations and temperature on the end of a light transparent lens located within the sensor probe. The end of the lens within the sensor probe contains a lens containing a layer of hydrogen permeable material which excludes other reactive gases, a layer of reflective metal material that forms a metal hydride upon absorbing hydrogen, and a layer of semi-conducting solid that is transparent above a temperature dependent minimum wavelength for temperature detection. The three layers of materials are located at the distal end of the lens located within the sensor probe. The lens focuses light generated by broad-band light generator and connected by fiber-optics to the sensor probe, onto a reflective metal material layer, which passes through the semi-conducting solid layer, onto two optical fibers located at the base of the sensor probe. The reflected light is transmitted over fiber optic cables to a spectrometer and system controller. The absence of electrical signals and electrical wires in the sensor probe provides for an elimination of the potential for spark sources when monitoring in hydrogen rich environments, and provides a sensor free from electrical interferences. 3 figs.

A Study of a QCM Sensor Based on TiO₂ Nanostructures for the Detection of NO₂ and Explosives Vapours in Air.

PubMed

Procek, Marcin; Stolarczyk, Agnieszka; Pustelny, Tadeusz; Maciak, Erwin

2015-04-22

The paper deals with investigations concerning the construction of sensors based on a quartz crystal microbalance (QCM) containing a TiO2 nanostructures sensor layer. A chemical method of synthesizing these nanostructures is presented. The prepared prototype of the QCM sensing system, as well as the results of tests for detecting low NO2 concentrations in an atmosphere of synthetic air have been described. The constructed NO2 sensors operate at room temperature, which is a great advantage, because resistance sensors based on wide gap semiconductors often require much higher operation temperatures, sometimes as high as 500 °C. The sensors constructed by the authors can be used, among other applications, in medical and chemical diagnostics, and also for the purpose of detecting explosive vapours. Reactions of the sensor to nitroglycerine vapours are presented as an example of its application. The influence of humidity on the operation of the sensor was studied.

Regulatory Considerations of Lower Cost Air Pollution Sensor Data Performance

EPA Science Inventory

Low-cost, portable air quality sensors could be the next generation of air monitoring, however, this nascent technology is not without risk. This article looks at how the U.S. Environmental Protection Agency (EPA) uses air monitoring data, the procedures followed to ensure and a...

Calibration and temperature correction of heat dissipation matric potential sensors

USGS Publications Warehouse

Flint, A.L.; Campbell, G.S.; Ellett, K.M.; Calissendorff, C.

2002-01-01

This paper describes how heat dissipation sensors, used to measure soil water matric potential, were analyzed to develop a normalized calibration equation and a temperature correction method. Inference of soil matric potential depends on a correlation between the variable thermal conductance of the sensor's porous ceramic and matric poten-tial. Although this correlation varies among sensors, we demonstrate a normalizing procedure that produces a single calibration relationship. Using sensors from three sources and different calibration methods, the normalized calibration resulted in a mean absolute error of 23% over a matric potential range of -0.01 to -35 MPa. Because the thermal conductivity of variably saturated porous media is temperature dependent, a temperature correction is required for application of heat dissipation sensors in field soils. A temperature correction procedure is outlined that reduces temperature dependent errors by 10 times, which reduces the matric potential measurement errors by more than 30%. The temperature dependence is well described by a thermal conductivity model that allows for the correction of measurements at any temperature to measurements at the calibration temperature.

A Fiber Bragg Grating Temperature Sensor for 2-400 K

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zaynetdinov, Madrakhim; See, Erich M.; Geist, Brian

2015-03-01

We demonstrate fiber optic, multiplexible temperature sensing using a fiber Bragg grating (FBG) with an operational range of 2-400 K, and a temperature resolution better than 10 mK for temperatures < 12 K. This represents a significant reduction in the lowest usable temperature as well as a significant increase in sensitivity at cryogenic temperatures compared with previously reported multiplexible solutions. This is accomplished by mounting the section of the fiber with a FBG on a polytetrafluoroethylene coupon, which has a non-negligible coefficient of thermal expansion down to < 4 K. The sensors exhibit a good stability over multiple temperature cyclesmore » and acceptable sensor-to-sensor repeatability. Possible applications for this sensor include distributed temperature sensing across superconducting elements and cryogenic temperature measurements in environments where electrical measurements are impractical or unsafe.« less

Development of advanced high-temperature heat flux sensors

NASA Technical Reports Server (NTRS)

Atkinson, W. H.; Strange, R. R.

1982-01-01

Various configurations of high temperature, heat flux sensors were studied to determine their suitability for use in experimental combustor liners of advanced aircraft gas turbine engines. It was determined that embedded thermocouple sensors, laminated sensors, and Gardon gauge sensors, were the most viable candidates. Sensors of all three types were fabricated, calibrated, and endurance tested. All three types of sensors met the fabricability survivability, and accuracy requirements established for their application.

Optical Pressure-Temperature Sensor for a Combustion Chamber

NASA Technical Reports Server (NTRS)

Wiley, John; Korman, Valentin; Gregory, Don

2008-01-01

A compact sensor for measuring temperature and pressure in a combusti on chamber has been proposed. The proposed sensor would include two optically birefringent, transmissive crystalline wedges: one of sapph ire (Al2O3) and one of magnesium oxide (MgO), the optical properties of both of which vary with temperature and pressure. The wedges wou ld be separated by a vapor-deposited thin-film transducer, which wou ld be primarily temperaturesensitive (in contradistinction to pressur e- sensitive) when attached to a crystalline substrate. The sensor w ould be housed in a rugged probe to survive the extreme temperatures and pressures in a combustion chamber.

Measuring centimeter-resolution air temperature profiles above land and water using fiber-optic Distributed Temperature Sensing

NASA Astrophysics Data System (ADS)

Sigmund, Armin; Pfister, Lena; Olesch, Johannes; Thomas, Christoph K.

2016-04-01

The precise determination of near-surface air temperature profiles is of special importance for the characterization of airflows (e.g. cold air) and the quantification of sensible heat fluxes according to the flux-gradient similarity approach. In contrast to conventional multi-sensor techniques, measuring temperature profiles using fiber-optic Distributed Temperature Sensing (DTS) provides thousands of measurements referenced to a single calibration standard at much reduced costs. The aim of this work was to enhance the vertical resolution of Raman scatter DTS measurements up to the centimeter-scale using a novel approach for atmospheric applications: the optical fiber was helically coiled around a meshed fabric. In addition to testing the new fiber geometry, we quantified the measurement uncertainty and demonstrated the benefits of the enhanced-resolution profiles. The fiber-optic cable was coiled around a hollow column consisting of white reinforcing fabric supported by plexiglass rings every meter. Data from two columns of this type were collected for 47 days to measure air temperature vertically over 3.0 and 5.1 m over a gently inclined meadow and over and in a small lake, respectively. Both profiles had a vertical resolution of 1 cm in the lower section near the surface and 5 cm in the upper section with an along-fiber instrument-specific averaging of 1.0 m and a temporal resolution of 30 s. Measurement uncertainties, especially from conduction between reinforcing fabric and fiber-optic cable, were estimated by modeling the fiber temperature via a detailed energy balance approach. Air temperature, wind velocity and radiation components were needed as input data and measured separately. The temperature profiles revealed valuable details, especially in the lowest 1 m above surface. This was best demonstrated for nighttime observations when artefacts due to solar heating did not occur. For example, the dynamics of a cold air layer was detected in a clear night

Low-Temperature Photochemically Activated Amorphous Indium-Gallium-Zinc Oxide for Highly Stable Room-Temperature Gas Sensors.

PubMed

Jaisutti, Rawat; Kim, Jaeyoung; Park, Sung Kyu; Kim, Yong-Hoon

2016-08-10

We report on highly stable amorphous indium-gallium-zinc oxide (IGZO) gas sensors for ultraviolet (UV)-activated room-temperature detection of volatile organic compounds (VOCs). The IGZO sensors fabricated by a low-temperature photochemical activation process and exhibiting two orders higher photocurrent compared to conventional zinc oxide sensors, allowed high gas sensitivity against various VOCs even at room temperature. From a systematic analysis, it was found that by increasing the UV intensity, the gas sensitivity, response time, and recovery behavior of an IGZO sensor were strongly enhanced. In particular, under an UV intensity of 30 mW cm(-2), the IGZO sensor exhibited gas sensitivity, response time and recovery time of 37%, 37 and 53 s, respectively, against 750 ppm concentration of acetone gas. Moreover, the IGZO gas sensor had an excellent long-term stability showing around 6% variation in gas sensitivity over 70 days. These results strongly support a conclusion that a low-temperature solution-processed amorphous IGZO film can serve as a good candidate for room-temperature VOCs sensors for emerging wearable electronics.

Development of MEMS wireless wall temperature sensor for combustion studies

NASA Astrophysics Data System (ADS)

Lee, Minhyeok; Morimoto, Kenichi; Suzuki, Yuji

2017-03-01

In this paper, a MEMS-based wireless wall temperature sensor for application to combustion studies is proposed. The resonant frequency change of an LCR circuit on the sensor is used to detect the temperature change, and is transferred by inductive coupling between the sensor and the read-out coil. Sensitivity analysis has been made to examine the effect of the resistance/capacitance change of the sensor on the resonant frequency shifts. Based on the present analysis, the sensing principle with either TCR (temperature coefficient of resistance) or TCP (temperature coefficient of permittivity) can be determined for better temperature sensitivity. The sensor configuration is designed through an equivalent circuit model, and verified with a 3D electromagnetic simulation. A prototype sensor on a glass substrate is successfully fabricated through MEMS technologies. Performance of the sensor is evaluated in the steady thermal field with the temperature range from 25 °C to 175 °C. The profile of the resonant frequency change is well fitted with a quadratic curve derived from the model analysis. The temperature measurement accuracy of 1.6 °C at 25 °C and 0.87 °C at 175 °C has been obtained at the measurement distance of 0.71 mm. In addition, a similar measurement uncertainty can be achieved with a 52 ms measurement time interval.

AOI [3] High-Temperature Nano-Derived Micro-H 2 and - H 2S Sensors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sabolsky, Edward M.

2014-08-01

The emissions from coal-fired power plants remain a significant concern for air quality. This environmental challenge must be overcome by controlling the emission of sulfur dioxide (SO 2) and hydrogen sulfide (H 2S) throughout the entire coal combustion process. One of the processes which could specifically benefit from robust, low cost, and high temperature compatible gas sensors is the coal gasification process which converts coal and/or biomass into syngas. Hydrogen (H 2), carbon monoxide (CO) and sulfur compounds make up 33%, 43% and 2% of syngas, respectively. Therefore, development of a high temperature (>500°C) chemical sensor for in-situ monitoring ofmore » H 2, H 2S and SO2 2 levels during coal gasification is strongly desired. The selective detection of SO 2/H 2S in the presence of H 2, is a formidable task for a sensor designer. In order to ensure effective operation of these chemical sensors, the sensor system must inexpensively function within harsh temperature and chemical environment. Currently available sensing approaches, which are based on gas chromatography, electrochemistry, and IR-spectroscopy, do not satisfy the required cost and performance targets. This work focused on the development microsensors that can be applied to this application. In order to develop the high- temperature compatible microsensor, this work addressed various issues related to sensor stability, selectivity, and miniaturization. In the research project entitled “High-Temperature Nano-Derived Micro-H 2 and -H 2S Sensors”, the team worked to develop micro-scale, chemical sensors and sensor arrays composed of nano-derived, metal-oxide composite materials to detect gases like H 2, SO 2, and H 2S within high-temperature environments (>500°C). The research was completed in collaboration with NexTech Materials, Ltd. (Lewis Center, Ohio). NexTech assisted in the testing of the sensors in syngas with contaminate levels of H 2S. The idea of including nanomaterials as the

Retrieval of air temperatures from crowd-sourced battery temperatures of cell phones

NASA Astrophysics Data System (ADS)

Overeem, Aart; Robinson, James; Leijnse, Hidde; Uijlenhoet, Remko; Steeneveld, Gert-Jan; Horn, Berthold K. P.

2013-04-01

Accurate air temperature observations are important for urban meteorology, for example to study the urban heat island and adverse effects of high temperatures on human health. The number of available temperature observations is often relatively limited. A new development is presented to derive temperature information for the urban canopy from an alternative source: cell phones. Battery temperature data were collected by users of an Android application for cell phones (opensignal.com). The application automatically sends battery temperature data to a server for storage. In this study, battery temperatures are averaged in space and time to obtain daily averaged battery temperatures for each city separately. A regression model, which can be related to a physical model, is employed to retrieve daily air temperatures from battery temperatures. The model is calibrated with observed air temperatures from a meteorological station of an airport located in or near the city. Time series of air temperatures are obtained for each city for a period of several months, where 50% of the data is for independent verification. Results are presented for Buenos Aires, London, Los Angeles, Paris, Mexico City, Moscow, Rome, and Sao Paulo. The evolution of the retrieved air temperatures often correspond well with the observed ones. The mean absolute error of daily air temperatures is less than 2 degrees Celsius, and the bias is within 1 degree Celsius. This shows that monitoring air temperatures employing an Android application holds great promise. Since 75% of the world's population has a cell phone, 20% of the land surface of the earth has cellular telephone coverage, and 500 million devices use the Android operating system, there is a huge potential for measuring air temperatures employing cell phones. This could eventually lead to real-time world-wide temperature maps.

A fiber air-gap Fabry-Pérot temperature sensor demodulated by using frequency modulated continuous wave

NASA Astrophysics Data System (ADS)

Zheng, Wanfu; Xie, Jianglei; Li, Yi; Xu, Ben; Kang, Juan; Shen, Changyu; Wang, Jianfeng; Jin, Yongxing; Liu, Honglin; Ni, Kai; Dong, Xinyong; Zhao, Chunliu; Jin, Shangzhong

In this study, a fiber in-line air-gap Fabry-Pérot interferometer (FPI) is fabricated by HF acid etching. For a low-cost and higher precise measurement, a demodulation system based on frequency modulated continuous wave (FMCW) technique is build up and demonstrated in this air-gap FPI. In temperature measurements, the temperature sensitivity is about 1.75 rad/°C by phase shift detection. We also test the long term performance of the system and the RMS error is about 0.04 rad, which corresponds to the temperature resolution of ~0.02 °C. It is much higher than the measurement resolution by using the traditional wavelength shift detection method. Our experiments show that the FMCW can provide a low-cost, high resolution and high speed interrogation solution to the fiber FPIs.

Low-Cost Wireless Temperature Measurement: Design, Manufacture, and Testing of a PCB-Based Wireless Passive Temperature Sensor.

PubMed

Yan, Dan; Yang, Yong; Hong, Yingping; Liang, Ting; Yao, Zong; Chen, Xiaoyong; Xiong, Jijun

2018-02-10

Low-cost wireless temperature measurement has significant value in the food industry, logistics, agriculture, portable medical equipment, intelligent wireless health monitoring, and many areas in everyday life. A wireless passive temperature sensor based on PCB (Printed Circuit Board) materials is reported in this paper. The advantages of the sensor include simple mechanical structure, convenient processing, low-cost, and easiness in integration. The temperature-sensitive structure of the sensor is a dielectric-loaded resonant cavity, consisting of the PCB substrate. The sensitive structure also integrates a patch antenna for the transmission of temperature signals. The temperature sensing mechanism of the sensor is the dielectric constant of the PCB substrate changes with temperature, which causes the resonant frequency variation of the resonator. Then the temperature can be measured by detecting the changes in the sensor's working frequency. The PCB-based wireless passive temperature sensor prototype is prepared through theoretical design, parameter analysis, software simulation, and experimental testing. The high- and low-temperature sensing performance of the sensor is tested, respectively. The resonant frequency decreases from 2.434 GHz to 2.379 GHz as the temperature increases from -40 °C to 125 °C. The fitting curve proves that the experimental data have good linearity. Three repetitive tests proved that the sensor possess well repeatability. The average sensitivity is 347.45 KHz / ℃ from repetitive measurements conducted three times. This study demonstrates the feasibility of the PCB-based wireless passive sensor, which provides a low-cost temperature sensing solution for everyday life, modern agriculture, thriving intelligent health devices, and so on, and also enriches PCB product lines and applications.

Niphargus: a silicon band-gap sensor temperature logger for high-precision environmental monitoring

NASA Astrophysics Data System (ADS)

Burlet, Christian; Vanbrabant, Yves; Piessens, Kris; Welkenhuysen, Kris; Verheyden, Sophie

2014-05-01

A temperature logger, called 'Niphargus', was developed at the Geological Survey of Belgium to monitor temperature of local natural processes with sensitivity of the order of a few hundredths of degrees to monitor temperature variability in open air, caves, soils and rivers. The newly developed instrument uses a state-of-the-art band-gap silicon temperature sensor with digital output. This sensor reduces the risk of drift associated with thermistor-based sensing devices, especially in humid environments. The Niphargus is designed to be highly reliable, low-cost and powered by a single lithium cell with up to several years autonomy depending on the sampling rate and environmental conditions. The Niphargus was evaluated in an ice point bath experiment in terms of temperature accuracy and thermal inertia. The small size and low power consumption of the logger allow its use in difficult accessible environments, e.g. caves and space-constrained applications, inside a rock in a water stream. In both cases, the loggers have proven to be reliable and accurate devices. For example, spectral analysis of the temperature signal in the Han caves (Belgium) allowed detection and isolation of a 0.005° C amplitude day-night periodic signal in the temperature curve. PIC Figure 1: a Niphargus logger in its standard size. SMD components side. Photo credit: W. Miseur

Wirelessly Interrogated Wear or Temperature Sensors

NASA Technical Reports Server (NTRS)

Woodard, Stanley E.; Taylor, Bryant D.

2010-01-01

Sensors for monitoring surface wear and/or temperature without need for wire connections have been developed. Excitation and interrogation of these sensors are accomplished by means of a magnetic-field-response recorder. In a sensor of the present type as in the previously reported ones, the capacitance and, thus, the resonance frequency, varies as a known function of the quantity of interest that one seeks to determine. Hence, the resonance frequency is measured and used to calculate the quantity of interest.

Core-temperature sensor ingestion timing and measurement variability.

PubMed

Domitrovich, Joseph W; Cuddy, John S; Ruby, Brent C

2010-01-01

Telemetric core-temperature monitoring is becoming more widely used as a noninvasive means of monitoring core temperature during athletic events. To determine the effects of sensor ingestion timing on serial measures of core temperature during continuous exercise. Crossover study. Outdoor dirt track at an average ambient temperature of 4.4°C ± 4.1°C and relative humidity of 74.1% ± 11.0%. Seven healthy, active participants (3 men, 4 women; age  =  27.0 ± 7.5 years, height  =  172.9 ± 6.8 cm, body mass  =  67.5 ± 6.1 kg, percentage body fat  =  12.7% ± 6.9%, peak oxygen uptake [Vo(2peak)]  =  54.4 ± 6.9 mL•kg⁻¹•min⁻¹) completed the study. Participants completed a 45-minute exercise trial at approximately 70% Vo(2peak). They consumed core-temperature sensors at 24 hours (P1) and 40 minutes (P2) before exercise. Core temperature was recorded continuously (1-minute intervals) using a wireless data logger worn by the participants. All data were analyzed using a 2-way repeated-measures analysis of variance (trial × time), Pearson product moment correlation, and Bland-Altman plot. Fifteen comparisons were made between P1 and P2. The main effect of time indicated an increase in core temperature compared with the initial temperature. However, we did not find a main effect for trial or a trial × time interaction, indicating no differences in core temperature between the sensors (P1  =  38.3°C ± 0.2°C, P2  =  38.3°C ± 0.4°C). We found no differences in the temperature recordings between the 2 sensors. These results suggest that assumed sensor location (upper or lower gastrointestinal tract) does not appreciably alter the transmission of reliable and repeatable measures of core temperature during continuous running in the cold.

A Polymer Optical Fiber Temperature Sensor Based on Material Features.

PubMed

Leal-Junior, Arnaldo; Frizera-Netoc, Anselmo; Marques, Carlos; Pontes, Maria José

2018-01-19

This paper presents a polymer optical fiber (POF)-based temperature sensor. The operation principle of the sensor is the variation in the POF mechanical properties with the temperature variation. Such mechanical property variation leads to a variation in the POF output power when a constant stress is applied to the fiber due to the stress-optical effect. The fiber mechanical properties are characterized through a dynamic mechanical analysis, and the output power variation with different temperatures is measured. The stress is applied to the fiber by means of a 180° curvature, and supports are positioned on the fiber to inhibit the variation in its curvature with the temperature variation. Results show that the sensor proposed has a sensitivity of 1.04 × 10 -3 °C -1 , a linearity of 0.994, and a root mean squared error of 1.48 °C, which indicates a relative error of below 2%, which is lower than the ones obtained for intensity-variation-based temperature sensors. Furthermore, the sensor is able to operate at temperatures up to 110 °C, which is higher than the ones obtained for similar POF sensors in the literature.

Nanometric Integrated Temperature and Thermal Sensors in CMOS-SOI Technology

PubMed Central

Malits, Maria; Nemirovsky, Yael

2017-01-01

This paper reviews and compares the thermal and noise characterization of CMOS (complementary metal-oxide-semiconductor) SOI (Silicon on insulator) transistors and lateral diodes used as temperature and thermal sensors. DC analysis of the measured sensors and the experimental results in a broad (300 K up to 550 K) temperature range are presented. It is shown that both sensors require small chip area, have low power consumption, and exhibit linearity and high sensitivity over the entire temperature range. However, the diode’s sensitivity to temperature variations in CMOS-SOI technology is highly dependent on the diode’s perimeter; hence, a careful calibration for each fabrication process is needed. In contrast, the short thermal time constant of the electrons in the transistor’s channel enables measuring the instantaneous heating of the channel and to determine the local true temperature of the transistor. This allows accurate “on-line” temperature sensing while no additional calibration is needed. In addition, the noise measurements indicate that the diode’s small area and perimeter causes a high 1/f noise in all measured bias currents. This is a severe drawback for the sensor accuracy when using the sensor as a thermal sensor; hence, CMOS-SOI transistors are a better choice for temperature sensing. PMID:28758932

Nanometric Integrated Temperature and Thermal Sensors in CMOS-SOI Technology.

PubMed

Malits, Maria; Nemirovsky, Yael

2017-07-29

This paper reviews and compares the thermal and noise characterization of CMOS (complementary metal-oxide-semiconductor) SOI (Silicon on insulator) transistors and lateral diodes used as temperature and thermal sensors. DC analysis of the measured sensors and the experimental results in a broad (300 K up to 550 K) temperature range are presented. It is shown that both sensors require small chip area, have low power consumption, and exhibit linearity and high sensitivity over the entire temperature range. However, the diode's sensitivity to temperature variations in CMOS-SOI technology is highly dependent on the diode's perimeter; hence, a careful calibration for each fabrication process is needed. In contrast, the short thermal time constant of the electrons in the transistor's channel enables measuring the instantaneous heating of the channel and to determine the local true temperature of the transistor. This allows accurate "on-line" temperature sensing while no additional calibration is needed. In addition, the noise measurements indicate that the diode's small area and perimeter causes a high 1/ f noise in all measured bias currents. This is a severe drawback for the sensor accuracy when using the sensor as a thermal sensor; hence, CMOS-SOI transistors are a better choice for temperature sensing.

Effects of electrostatic discharge on three cryogenic temperature sensor models

NASA Astrophysics Data System (ADS)

Courts, S. Scott; Mott, Thomas B.

2014-01-01

Cryogenic temperature sensors are not usually thought of as electrostatic discharge (ESD) sensitive devices. However, the most common cryogenic thermometers in use today are thermally sensitive diodes or resistors - both electronic devices in their base form. As such, they are sensitive to ESD at some level above which either catastrophic or latent damage can occur. Instituting an ESD program for safe handling and installation of the sensor is costly and it is desirable to balance the risk of ESD damage against this cost. However, this risk cannot be evaluated without specific knowledge of the ESD vulnerability of the devices in question. This work examines three types of cryogenic temperature sensors for ESD sensitivity - silicon diodes, Cernox{trade mark, serif} resistors, and wire wound platinum resistors, all manufactured by Lake Shore Cryotronics, Inc. Testing was performed per TIA/EIA FOTP129 (Human Body Model). Damage was found to occur in the silicon diode sensors at discharge levels of 1,500 V. For Cernox{trade mark, serif} temperature sensors, damage was observed at 3,500 V. The platinum temperature sensors were not damaged by ESD exposure levels of 9,900 V. At the lower damage limit, both the silicon diode and the Cernox{trade mark, serif} temperature sensors showed relatively small calibration shifts of 1 to 3 K at room temperature. The diode sensors were stable with time and thermal cycling, but the long term stability of the Cernox{trade mark, serif} sensors was degraded. Catastrophic failure occurred at higher levels of ESD exposure.

A temperature-compensated optical fiber force sensor for minimally invasive surgeries

NASA Astrophysics Data System (ADS)

Mo, Z.; Xu, W.; Broderick, N.; Chen, H.

2015-12-01

Force sensing in minimally invasive surgery (MIS) is a chronic problem since it has an intensive magnetic resonance (MR) operation environment, which causes a high influence to traditional electronic force sensors. Optical sensor is a promising choice in this area because it is immune to MR influence. However, the changing temperature introduces a lot of noise signals to them, which is the main obstacle for optical sensing applications in MIS. This paper proposes a miniature temperature-compensated optical force sensor by using Fabry-Perot interference (FPI) principle. It can be integrated into medical tools' tips and the temperature noise is decreased by using a reference FPI temperature sensor. An injection needle with embedded temperature-compensated FPI force sensor has been fabricated and tested. And the comparison between temperature-force simulation results and the temperature-force experiment results has been carried out.

Development of a fast temperature sensor for combustion gases using a single tunable diode laser

NASA Astrophysics Data System (ADS)

Zhou, X.; Jeffries, J. B.; Hanson, R. K.

2005-09-01

The 12 best NIR water transition line pairs for temperature measurements with a single DFB laser in flames are determined by systematic analysis of the HITRAN simulation of the water spectra in the 1-2 μm spectral region. A specific line pair near 1.4 μm was targeted for non-intrusive measurements of gas temperature in combustion systems using a scanned-wavelength technique with wavelength modulation and 2f detection. This sensor uses a single diode laser (distributed-feedback), operating near 1.4 μm and is wavelength scanned over a pair of H2O absorption transitions (7154.354 cm-1 & 7153.748 cm-1) at a 2 kHz repetition rate. The wavelength is modulated (f=500 kHz) with modulation amplitude a=0.056 cm-1. Gas temperature is inferred from the ratio of the second harmonic signals of the two selected H2O transitions. The fiber-coupled-single-laser design makes the system compact, rugged, low cost and simple to assemble. As part of the sensor development effort, design rules were applied to optimize the line selection, and fundamental spectroscopic parameters of the selected transitions were determined via laboratory measurements including the temperature-dependent line strength, self-broadening coefficients, and air-broadening coefficients. The new sensor design includes considerations of hardware and software to enable fast data acquisition and analysis; a temperature readout rate of 2 kHz was demonstrated for measurements in a laboratory flame at atmospheric pressure. The combination of scanned-wavelength and wavelength-modulation minimizes interference from emission and beam steering, resulting in a robust temperature sensor that is promising for combustion control applications.

Noise analysis in air-coupled PVDF ultrasonic sensors.

PubMed

Fiorillo, A S

2000-01-01

In this paper we analyze the noise generated in a piezo-polymer based sensor for low frequency ultrasound in air. The sensor includes two curved PVDF transducers for medium and short range applications. A lumped RLC equivalent circuit was derived from the measurement of the transducer's electrical admittance, in air, by taking into account both mechanical and dielectric losses, which we suppose are the major sources of noise in similar devices. The electrical model was used to study and optimize the noise performance of a 61 kHz transducer and to simulate the electrical behavior of the complete transmitter-receiver system. The validity of the overall electrical model with low noise was confirmed after verifying, with Pspice, agreement of the practical and theoretical results.

Fast response air-to-fuel ratio measurements using a novel device based on a wide band lambda sensor

NASA Astrophysics Data System (ADS)

Regitz, S.; Collings, N.

2008-07-01

A crucial parameter influencing the formation of pollutant gases in internal combustion engines is the air-to-fuel ratio (AFR). During transients on gasoline and diesel engines, significant AFR excursions from target values can occur, but cycle-by-cycle AFR resolution, which is helpful in understanding the origin of deviations, is difficult to achieve with existing hardware. This is because current electrochemical devices such as universal exhaust gas oxygen (UEGO) sensors have a time constant of 50-100 ms, depending on the engine running conditions. This paper describes the development of a fast reacting device based on a wide band lambda sensor which has a maximum time constant of ~20 ms and enables cyclic AFR measurements for engine speeds of up to ~4000 rpm. The design incorporates a controlled sensor environment which results in insensitivity to sample temperature and pressure. In order to guide the development process, a computational model was developed to predict the effect of pressure and temperature on the diffusion mechanism. Investigations regarding the sensor output and response were carried out, and sensitivities to temperature and pressure are examined. Finally, engine measurements are presented.

Development of an environmental chamber for evaluating the performance of low-cost air quality sensors under controlled conditions

NASA Astrophysics Data System (ADS)

Papapostolou, Vasileios; Zhang, Hang; Feenstra, Brandon J.; Polidori, Andrea

2017-12-01

A state-of-the-art integrated chamber system has been developed for evaluating the performance of low-cost air quality sensors. The system contains two professional grade chamber enclosures. A 1.3 m3 stainless-steel outer chamber and a 0.11 m3 Teflon-coated stainless-steel inner chamber are used to create controlled aerosol and gaseous atmospheres, respectively. Both chambers are temperature and relative humidity controlled with capability to generate a wide range of environmental conditions. The system is equipped with an integrated zero-air system, an ozone and two aerosol generation systems, a dynamic dilution calibrator, certified gas cylinders, an array of Federal Reference Method (FRM), Federal Equivalent Method (FEM), and Best Available Technology (BAT) reference instruments and an automated control and sequencing software. Our experiments have demonstrated that the chamber system is capable of generating stable and reproducible aerosol and gas concentrations at low, medium, and high levels. This paper discusses the development of the chamber system along with the methods used to quantitatively evaluate sensor performance. Considering that a significant number of academic and research institutions, government agencies, public and private institutions, and individuals are becoming interested in developing and using low-cost air quality sensors, it is important to standardize the procedures used to evaluate their performance. The information discussed herein provides a roadmap for entities who are interested in characterizing air quality sensors in a rigorous, systematic and reproducible manner.

Application of High-Temperature Extrinsic Fabry-Perot Interferometer Strain Sensor

NASA Technical Reports Server (NTRS)

Piazza, Anthony

2008-01-01

In this presentation to the NASA Aeronautics Sensor Working Group the application of a strain sensor is outlined. The high-temperature extrinsic Fabry-Perot interferometer (EFPI) strain sensor was developed due to a need for robust strain sensors that operate accurately and reliably beyond 1800 F. Specifically, the new strain sensor would provide data for validating finite element models and thermal-structural analyses. Sensor attachment techniques were also developed to improve methods of handling and protecting the fragile sensors during the harsh installation process. It was determined that thermal sprayed attachments are preferable even though cements are simpler to apply as cements are more prone to bond failure and are often corrosive. Previous thermal/mechanical cantilever beam testing of EFPI yielded very little change to 1200 F, with excellent correlation with SG to 550 F. Current combined thermal/mechanical loading for sensitivity testing is accomplished by a furnace/cantilever beam loading system. Dilatometer testing has can also be used in sensor characterization to evaluate bond integrity, evaluate sensitivity and accuracy and to evaluate sensor-to-sensor scatter, repeatability, hysteresis and drift. Future fiber optic testing will examine single-mode silica EFPIs in a combined thermal/mechanical load fixture on C-C and C-SiC substrates, develop a multi-mode Sapphire strain-sensor, test and evaluate high-temperature fiber Bragg Gratings for use as strain and temperature sensors and attach and evaluate a high-temperature heat flux gauge.

Development of High Temperature Gas Sensor Technology

NASA Technical Reports Server (NTRS)

Hunter, Gary W.; Chen, Liang-Yu; Neudeck, Philip G.; Knight, Dak; Liu, Chung-Chiun; Wu, Quing-Hai; Zhou, Huan-Jun

1997-01-01

The measurement of engine emissions is important for their monitoring and control. However, the ability to measure these emissions in-situ is limited. We are developing a family of high temperature gas sensors which are intended to operate in harsh environments such as those in an engine. The development of these sensors is based on progress in two types of technology: (1) The development of SiC-based semiconductor technology; and (2) Improvements in micromachining and microfabrication technology. These technologies are being used to develop point-contact sensors to measure gases which are important in emission control especially hydrogen, hydrocarbons, nitrogen oxides, and oxygen. The purpose of this paper is to discuss the development of this point-contact sensor technology. The detection of each type of gas involves its own challenges in the fields of materials science and fabrication technology. Of particular importance is sensor sensitivity, selectivity, and stability in long-term, high temperature operation. An overview is presented of each sensor type with an evaluation of its stage of development. It is concluded that this technology has significant potential for use in engine applications but further development is necessary.

Improved spatial monitoring of air temperature in forested complex terrain: an energy-balance based calibration method

NASA Astrophysics Data System (ADS)

Kennedy, A. M.; Thomas, C. K.; Pypker, T. G.; Bond, B. J.; Selker, J. S.; Unsworth, M. H.

2009-12-01

Fiber-optic distributed temperature sensing (DTS) has great potential for spatial monitoring in hydrology and atmospheric science. DTS systems have an advantage over conventional individual temperature sensors in that thousands of quasi-concurrent temperature measurements may be made along the entire length of a fiber at 1 meter increments by a single instrument, thus increasing measurement precision. However, like any other temperature sensors, the fiber temperature is influenced by energy exchange with its environment, particularly by radiant energy (solar and long-wave) and by wind speed. The objective of this research is to perform an energy-balance based calibration of a DTS fiber system that will reduce the uncertainty of air temperature measurements in open and forested environments. To better understand the physics controlling the fiber temperature reported by the DTS, alternating black and white fiber optic cables were installed on vertical wooden jigs inside a recirculating wind tunnel. A constant irradiance from six 600W halogen lamps was directed on a two meter section of fiber to permit controlled observations of the resulting temperature difference between the black and white fibers as wind speed was varied. The net short and longwave radiation balance of each fiber was measured with an Eppley pyranometer and Kipp and Zonen pyrgeometer. Additionally, accurate air temperature was recorded from a screened platinum resistance thermometer, and sonic anemometers were positioned to record wind speed and turbulence. Relationships between the temperature excess of each fiber, net radiation, and wind speed were developed and will be used to derive correction terms in future field work. Preliminary results indicate that differential heating of fibers (black-white) is driven largely by net radiation with wind having a smaller but consistent effect. Subsequent work will require field verification to confirm that the observed wind tunnel correction algorithms are

The Citizen Science Toolbox: A One-Stop Resource for Air Sensor Technology

EPA Science Inventory

The air sensor technology market is exploding with new sensors in all kinds of forms. Developers are putting sensors in wristbands, headphones, and cell phone add-ons. Small, portable and lower-cost measurement devices using sensors are coming on the market with a wide variety of...

Uncertainty in air quality observations using low-cost sensors

NASA Astrophysics Data System (ADS)

Castell, Nuria; Dauge, Franck R.; Dongol, Rozina; Vogt, Matthias; Schneider, Philipp

2016-04-01

Air pollution poses a threat to human health, and the WHO has classified air pollution as the world's largest single environmental health risk. In Europe, the majority of the population lives in areas where air quality levels frequently exceed WHO's ambient air quality guidelines. The emergence of low-cost, user-friendly and very compact air pollution platforms allowing observations at high spatial resolution in near real-time, provides us with new opportunities to simultaneously enhance existing monitoring systems as well as enable citizens to engage in more active environmental monitoring (citizen science). However the data sets generated by low-cost sensors show often questionable data quality. For many sensors, neither their error characteristics nor how their measurement capability holds up over time or through a range of environmental conditions, have been evaluated. We have conducted an exhaustive evaluation of the commercial low-cost platform AQMesh (measuring NO, NO2, CO, O3, PM10 and PM2.5) in laboratory and in real-world conditions in the city of Oslo (Norway). Co-locations in field of 24 platforms were conducted over a 6 month period (April to September 2015) allowing to characterize the temporal variability in the performance. Additionally, the field performance included the characterization on different monitoring urban monitoring sites characteristic of both traffic and background conditions. All the evaluations have been conducted against CEN reference method analyzers maintained according to the Norwegian National Reference Laboratory quality system. The results show clearly that a good performance in laboratory does not imply similar performance in real-world outdoor conditions. Moreover, laboratory calibration is not suitable for subsequent measurements in urban environments. In order to reduce the errors, sensors require on-site field calibration. Even after such field calibration, the platforms show a significant variability in the performance

Effects of Temperature and Air Density Profiles on Ozone Lidar Retrievals

NASA Astrophysics Data System (ADS)

Kirgis, G.; Langford, A. O.; Senff, C. J.; Alvarez, R. J. _II, II

2017-12-01

The recent reduction in the primary U.S. National Ambient Air Quality Standard (NAAQS) for ozone (O3) from 75 to 70 parts-per-billion by volume (ppbv) adds urgency to the need for better understanding of the processes that control ground-level concentrations in the United States. While ground-based in situ sensors are capable of measuring ozone levels, they don't give any insight into upper air transport and mixing. Differential absorption lidars such as the NOAA/ESRL Tunable Optical Profiler for Aerosol and oZone (TOPAZ) measure continuous vertical ozone profiles with high spatial and temporal resolution. However, the retrieved ozone mixing ratios depend on the temperature and air density profiles used in the analysis. This study analyzes the ozone concentrations for seven field campaigns from 2013 to 2016 to evaluate the impact of the assumed pressure and temperature profiles on the ozone mixing ratio retrieval. Pressure and temperature profiles from various spatial and temporal resolution models (Modern Era Retrospective-Analysis for Research and Applications, NCEP/NCAR Reanalysis, NCEP North American Regional Reanalysis, Rapid Refresh, and High-Resolution Rapid Refresh) are compared to reference ozone profiles created with pressure and temperature profiles from ozonesondes launched close to the TOPAZ measurement site. The results show significant biases with respect to time of day and season, altitude, and location of the model-extracted profiles. Limitations and advantages of all datasets used will also be discussed.

Microcantilever heater-thermometer with integrated temperature-compensated strain sensor

DOEpatents

King, William P [Champaign, IL; Lee, Jungchul [Champaign, IL; Goericke, Fabian T [Wolfsburg, DE

2011-04-19

The present invention provides microcantilever hotplate devices which incorporate temperature compensating strain sensors. The microcantilever hotplate devices of the present invention comprise microcantilevers having temperature compensating strain sensors and resistive heaters. The present invention also provides methods for using a microcantilever hotplate for temperature compensated surface stress measurements, chemical/biochemical sensing, measuring various properties of compounds adhered to the microcantilever hotplate surface, or for temperature compensated deflection measurements.

Low-Cost Wireless Temperature Measurement: Design, Manufacture, and Testing of a PCB-Based Wireless Passive Temperature Sensor

PubMed Central

Yan, Dan; Yang, Yong; Hong, Yingping; Liang, Ting; Yao, Zong; Chen, Xiaoyong; Xiong, Jijun

2018-01-01

Low-cost wireless temperature measurement has significant value in the food industry, logistics, agriculture, portable medical equipment, intelligent wireless health monitoring, and many areas in everyday life. A wireless passive temperature sensor based on PCB (Printed Circuit Board) materials is reported in this paper. The advantages of the sensor include simple mechanical structure, convenient processing, low-cost, and easiness in integration. The temperature-sensitive structure of the sensor is a dielectric-loaded resonant cavity, consisting of the PCB substrate. The sensitive structure also integrates a patch antenna for the transmission of temperature signals. The temperature sensing mechanism of the sensor is the dielectric constant of the PCB substrate changes with temperature, which causes the resonant frequency variation of the resonator. Then the temperature can be measured by detecting the changes in the sensor’s working frequency. The PCB-based wireless passive temperature sensor prototype is prepared through theoretical design, parameter analysis, software simulation, and experimental testing. The high- and low-temperature sensing performance of the sensor is tested, respectively. The resonant frequency decreases from 2.434 GHz to 2.379 GHz as the temperature increases from −40 °C to 125 °C. The fitting curve proves that the experimental data have good linearity. Three repetitive tests proved that the sensor possess well repeatability. The average sensitivity is 347.45 KHz/°C℃ from repetitive measurements conducted three times. This study demonstrates the feasibility of the PCB-based wireless passive sensor, which provides a low-cost temperature sensing solution for everyday life, modern agriculture, thriving intelligent health devices, and so on, and also enriches PCB product lines and applications. PMID:29439393

An Integrated-Circuit Temperature Sensor for Calorimetry and Differential Temperature Measurement.

ERIC Educational Resources Information Center

Muyskens, Mark A.

1997-01-01

Describes the application of an integrated-circuit (IC) chip which provides an easy-to-use, inexpensive, rugged, computer-interfaceable temperature sensor for calorimetry and differential temperature measurement. Discusses its design and advantages. (JRH)

Alumina ceramic based high-temperature performance of wireless passive pressure sensor

NASA Astrophysics Data System (ADS)

Wang, Bo; Wu, Guozhu; Guo, Tao; Tan, Qiulin

2016-12-01

A wireless passive pressure sensor equivalent to inductive-capacitive (LC) resonance circuit and based on alumina ceramic is fabricated by using high temperature sintering ceramic and post-fire metallization processes. Cylindrical copper spiral reader antenna and insulation layer are designed to realize the wireless measurement for the sensor in high temperature environment. The high temperature performance of the sensor is analyzed and discussed by studying the phase-frequency and amplitude-frequency characteristics of reader antenna. The average frequency change of sensor is 0.68 kHz/°C when the temperature changes from 27°C to 700°C and the relative change of twice measurements is 2.12%, with high characteristic of repeatability. The study of temperature-drift characteristic of pressure sensor in high temperature environment lays a good basis for the temperature compensation methods and insures the pressure signal readout accurately.

Fabrication of a Flexible Micro Temperature Sensor for Micro Reformer Applications

PubMed Central

Lee, Chi-Yuan; Lin, Chien-Hen; Lo, Yi-Man

2011-01-01

Micro reformers still face obstacles in minimizing their size, decreasing the concentration of CO, conversion efficiency and the feasibility of integrated fabrication with fuel cells. By using a micro temperature sensor fabricated on a stainless steel-based micro reformer, this work attempts to measure the inner temperature and increase the conversion efficiency. Micro temperature sensors on a stainless steel substrate are fabricated using micro-electro-mechanical systems (MEMS) and then placed separately inside the micro reformer. Micro temperature sensors are characterized by their higher accuracy and sensitivity than those of a conventional thermocouple. To the best of our knowledge, micro temperature sensors have not been embedded before in micro reformers and commercial products, therefore, this work presents a novel approach to integrating micro temperature sensors in a stainless steel-based micro reformer in order to evaluate inner local temperature distributions and enhance reformer performance. PMID:22163817

Temperature and pH sensors based on graphenic materials.

PubMed

Salvo, P; Calisi, N; Melai, B; Cortigiani, B; Mannini, M; Caneschi, A; Lorenzetti, G; Paoletti, C; Lomonaco, T; Paolicchi, A; Scataglini, I; Dini, V; Romanelli, M; Fuoco, R; Di Francesco, F

2017-05-15

Point-of-care applications and patients' real-time monitoring outside a clinical setting would require disposable and durable sensors to provide better therapies and quality of life for patients. This paper describes the fabrication and performances of a temperature and a pH sensor on a biocompatible and wearable board for healthcare applications. The temperature sensor was based on a reduced graphene oxide (rGO) layer that changed its electrical resistivity with the temperature. When tested in a human serum sample between 25 and 43°C, the sensor had a sensitivity of 110±10Ω/°C and an error of 0.4±0.1°C compared with the reference value set in a thermostatic bath. The pH sensor, based on a graphene oxide (GO) sensitive layer, had a sensitivity of 40±4mV/pH in the pH range between 4 and 10. Five sensor prototypes were tested in a human serum sample over one week and the maximum deviation of the average response from reference values obtained by a glass electrode was 0.2pH units. For biological applications, the temperature and pH sensors were successfully tested for in vitro cytotoxicity with human fibroblast cells (MRC-5) over 24h. Copyright © 2017 Elsevier B.V. All rights reserved.

Community Air Sensor Network (CAIRSENSE) project: Evaluation of low-cost sensor performance in a suburban environment in the southeastern United States

EPA Science Inventory

Advances in air pollution sensor technology have enabled the development of small and low cost systems to measure outdoor air pollution. The deployment of a large number of sensors across a small geographic area would have potential benefits to supplement traditional monitoring n...

Fabrication of a printed capacitive air-gap touch sensor

NASA Astrophysics Data System (ADS)

Lee, Sang Hoon; Seo, Hwiwon; Lee, Sangyoon

2018-05-01

Unlike lithography-based processes, printed electronics does not require etching, which makes it difficult to fabricate electronic devices with an air gap. In this study, we propose a method to fabricate capacitive air-gap touch sensors via printing and coating. First, the bottom electrode was fabricated on a flexible poly(ethylene terephthalate) (PET) substrate using roll-to-roll gravure printing with silver ink. Then poly(dimethylsiloxane) (PDMS) was spin coated to form a sacrificial layer. The top electrode was fabricated on the sacrificial layer by spin coating with a stretchable silver ink. The sensor samples were then put in a tetrabutylammonium (TBAF) bath to generate the air gap by removing the sacrificial layer. The capacitance of the samples was measured for verification, and the results show that the capacitance increases in proportion to the applied force from 0 to 2.5 N.

Comparison between core temperatures measured telemetrically using the CorTemp® ingestible temperature sensor and rectal temperature in healthy Labrador retrievers

PubMed Central

Osinchuk, Stephanie; Taylor, Susan M.; Shmon, Cindy L.; Pharr, John; Campbell, John

2014-01-01

This study evaluated the CorTemp® ingestible telemetric core body temperature sensor in dogs, to establish the relationship between rectal temperature and telemetrically measured core body temperature at rest and during exercise, and to examine the effect of sensor location in the gastrointestinal (GI) tract on measured core temperature. CorTemp® sensors were administered orally to fasted Labrador retriever dogs and radiographs were taken to document sensor location. Core and rectal temperatures were monitored throughout the day in 6 resting dogs and during a 10-minute strenuous retrieving exercise in 6 dogs. Time required for the sensor to leave the stomach (120 to 610 min) was variable. Measured core temperature was consistently higher than rectal temperature across all GI locations but temperature differences based on GI location were not significant (P = 0.5218). Resting dogs had a core temperature that was on average 0.4°C above their rectal temperature with 95% limits of agreement (LoA) between 1.2°C and −0.5°C. Core temperature in exercising dogs was on average 0.3°C higher than their concurrent rectal temperature, with LoA of +1.6°C and −1.1°C. PMID:25320380

Comparison between core temperatures measured telemetrically using the CorTemp® ingestible temperature sensor and rectal temperature in healthy Labrador retrievers.

PubMed

Osinchuk, Stephanie; Taylor, Susan M; Shmon, Cindy L; Pharr, John; Campbell, John

2014-10-01

This study evaluated the CorTemp(®) ingestible telemetric core body temperature sensor in dogs, to establish the relationship between rectal temperature and telemetrically measured core body temperature at rest and during exercise, and to examine the effect of sensor location in the gastrointestinal (GI) tract on measured core temperature. CorTemp(®) sensors were administered orally to fasted Labrador retriever dogs and radiographs were taken to document sensor location. Core and rectal temperatures were monitored throughout the day in 6 resting dogs and during a 10-minute strenuous retrieving exercise in 6 dogs. Time required for the sensor to leave the stomach (120 to 610 min) was variable. Measured core temperature was consistently higher than rectal temperature across all GI locations but temperature differences based on GI location were not significant (P = 0.5218). Resting dogs had a core temperature that was on average 0.4°C above their rectal temperature with 95% limits of agreement (LoA) between 1.2°C and -0.5°C. Core temperature in exercising dogs was on average 0.3°C higher than their concurrent rectal temperature, with LoA of +1.6°C and -1.1°C.

Efficient Skin Temperature Sensor and Stable Gel-Less Sticky ECG Sensor for a Wearable Flexible Healthcare Patch.

PubMed

Yamamoto, Yuki; Yamamoto, Daisuke; Takada, Makoto; Naito, Hiroyoshi; Arie, Takayuki; Akita, Seiji; Takei, Kuniharu

2017-09-01

Wearable, flexible healthcare devices, which can monitor health data to predict and diagnose disease in advance, benefit society. Toward this future, various flexible and stretchable sensors as well as other components are demonstrated by arranging materials, structures, and processes. Although there are many sensor demonstrations, the fundamental characteristics such as the dependence of a temperature sensor on film thickness and the impact of adhesive for an electrocardiogram (ECG) sensor are yet to be explored in detail. In this study, the effect of film thickness for skin temperature measurements, adhesive force, and reliability of gel-less ECG sensors as well as an integrated real-time demonstration is reported. Depending on the ambient conditions, film thickness strongly affects the precision of skin temperature measurements, resulting in a thin flexible film suitable for a temperature sensor in wearable device applications. Furthermore, by arranging the material composition, stable gel-less sticky ECG electrodes are realized. Finally, real-time simultaneous skin temperature and ECG signal recordings are demonstrated by attaching an optimized device onto a volunteer's chest. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Respirable particulate monitoring with remote sensors. (Public health ecology: Air pollution)

NASA Technical Reports Server (NTRS)

Severs, R. K.

1974-01-01

The feasibility of monitoring atmospheric aerosols in the respirable range from air or space platforms was studied. Secondary reflectance targets were located in the industrial area and near Galveston Bay. Multichannel remote sensor data were utilized to calculate the aerosol extinction coefficient and thus determine the aerosol size distribution. Houston Texas air sampling network high volume data were utilized to generate computer isopleth maps of suspended particulates and to establish the mass loading of the atmosphere. In addition, a five channel nephelometer and a multistage particulate air sampler were used to collect data. The extinction coefficient determined from remote sensor data proved more representative of wide areal phenomena than that calculated from on site measurements. It was also demonstrated that a significant reduction in the standard deviation of the extinction coefficient could be achieved by reducing the bandwidths used in remote sensor.

Polymer Substrate Temperature Sensor Array for Brain Interfaces

PubMed Central

Kim, Insoo; Fok, Ho Him R.; Li, Yuanyuan; Jackson, Thomas N.; Gluckman, Bruce J.

2012-01-01

We developed an implantable thin film transistor temperature sensor (TFT-TS) to measure temperature changes in the brain. These changes are assumed to be associated with cerebral metabolism and neuronal activity. Two prototype TFT-TSs were designed and tested in-vitro: one with 8 diode-connected single-ended sensors, and the other with 4 pairs of differential-ended sensors in an array configuration. The sensor elements are 25~100 μm in width and 5 μm in length. The TFT-TSs were fabricated based on high-speed ZnO TFT process technology on flexible polyimide substrates (50 μm thick, 500 μm width, 20 mm length). In order to interface external signal electronics, they were directly bonded to a prototype printed circuit board using anisotropic conductive films The prototypes were characterized between 20~40 °C using a surface mounted thermocouple and custom-designed temperature controlled oven. The maximum sensitivity of 40 mV/°C was obtained from the TFT-TS. PMID:22255041

Temperature-compensated strain measurement using FBG sensors embedded in composite laminates

NASA Astrophysics Data System (ADS)

Tanaka, Nobuhira; Okabe, Yoji; Takeda, Nobuo

2002-07-01

For accurate strain measurement by fiber Bragg grating (FBG) sensors, it is necessary to compensate the influence of temperature change. In this study two devices using FBG sensors have been developed for temperature-compensated strain measurement. They are named hybrid sensor and laminate sensor, respectively. The former consists of two different materials connected in series: carbon fiber reinforced plastic (CFRP) and glass fiber reinforced plastic (GFRP). Each material contains an FBG sensor with a different Bragg wavelength, and both ends of the device are glue to a structure. Using the difference of their Young's moduli and coefficients of thermal expansion (CTEs), both strain and temperature can be measured. The latter sensor is a laminate of two 90 degree(s) plies of CFRP and an epoxy plate, and an FBG sensor is embedded in the epoxy plate. When the temperature changes, the cross section of the optical fiber is deformed by the thermal residual stress. The deformation of the fiber causes the birefringence and widens the reflection spectrum. Since the temperature can be calculated from the spectrum width, which changes in proportion to the temperature, the accuracy of the strain measurement is improved. The usefulness of these sensors were experimentally confirmed.

Findings from the 2013 EPA Air Sensors Workshop

EPA Pesticide Factsheets

This article, first published in the January 2014 issue of EM Magazine, provides findings from the Air Sensors 2013: Data Quality & Applications workshop held in Research Triangle Park, N.C., in March 2013.

The influence of hard-baking temperature applied for SU8 sensor layer on the sensitivity of capacitive chemical sensor

NASA Astrophysics Data System (ADS)

Klanjšek Gunde, Marta; Hauptman, Nina; Maček, Marijan; Kunaver, Matjaž

2009-06-01

SU8, the near-UV photosensitive epoxy-based polymer was used as a sensor layer in the capacitive chemical sensor, ready for integration with a generic double-metal CMOS technology. It was observed that the response of the sensor slowly increases with the temperature applied in hard-baking process as long as it remains below 300°C. At this temperature the response of the sensor abruptly increases and becomes almost threefold. It was shown that fully crosslinked structure of the sensor layer becomes opened and disordered when the sensor is hard-baked at temperatures between 300°C and 320°C, that is, still well below the degradation temperature of the polymer. These changes in chemical structure were analyzed by Fourier-transform infrared spectroscopy. The temperature-dependent changes of the sensor layer structure enable one to prepare a combination of capacitive chemical sensors with good discrimination between some volatile organic compounds.

Temperature sensor based on an isopropanol-sealed photonic crystal fiber in-line interferometer with enhanced refractive index sensitivity.

PubMed

Qiu, Sun-jie; Chen, Ye; Xu, Fei; Lu, Yan-qing

2012-03-01

We fabricate a simple, compact, and stable temperature sensor based on a liquid-sealed photonic crystal fiber (PCF) in-line nonpolarimetric modal interferometer. Different from other reported PCF devices, it does not need expensive polarimetric devices, and the liquid is sealed in one fiber. The device consists of a stub of isopropanol-filled PCF spliced between standard single-mode fibers. The temperature sensitivity (-166 pm/°C) increases over an order of magnitude compared with those of the previous sensors based on air-sealed PCF interferometers built via fusion splicing with the same mechanism. In addition, the refractive index sensitivity also increases. Higher temperature sensitivity can be realized by infiltrating some liquid having a higher thermo-optic coefficient into the microholes of the PCF. © 2012 Optical Society of America

Optical temperature sensor using thermochromic semiconductors

DOEpatents

Kronberg, James W.

1996-01-01

An optical temperature measuring device utilizes thermochromic semiconductors which vary in color in response to changes in temperature. The thermochromic material is sealed in a glass matrix which allows the temperature sensor to detect high temperatures without breakdown. Cuprous oxide and cadmium sulfide are among the semiconductor materials which provide the best results. The changes in color may be detected visually or by utilizing an optical fiber and an electrical sensing circuit.

Optical temperature sensor using thermochromic semiconductors

DOEpatents

Kronberg, J.W.

1996-08-20

An optical temperature measuring device utilizes thermochromic semiconductors which vary in color in response to changes in temperature. The thermochromic material is sealed in a glass matrix which allows the temperature sensor to detect high temperatures without breakdown. Cuprous oxide and cadmium sulfide are among the semiconductor materials which provide the best results. The changes in color may be detected visually or by utilizing an optical fiber and an electrical sensing circuit. 7 figs.

Air Pollution Monitoring and Mining Based on Sensor Grid in London.

PubMed

Ma, Yajie; Richards, Mark; Ghanem, Moustafa; Guo, Yike; Hassard, John

2008-06-01

In this paper, we present a distributed infrastructure based on wireless sensors network and Grid computing technology for air pollution monitoring and mining, which aims to develop low-cost and ubiquitous sensor networks to collect real-time, large scale and comprehensive environmental data from road traffic emissions for air pollution monitoring in urban environment. The main informatics challenges in respect to constructing the high-throughput sensor Grid are discussed in this paper. We present a twolayer network framework, a P2P e-Science Grid architecture, and the distributed data mining algorithm as the solutions to address the challenges. We simulated the system in TinyOS to examine the operation of each sensor as well as the networking performance. We also present the distributed data mining result to examine the effectiveness of the algorithm.

Flexible Multiplexed Surface Temperature Sensor

NASA Technical Reports Server (NTRS)

Daryabeigi, Kamran; Dillon-Townes, L. A.; Johnson, Preston B.; Ash, Robert L.

1995-01-01

Unitary array of sensors measures temperatures at points distributed over designated area on surface. Useful in measuring surface temperatures of aerodynamic models and thermally controlled objects. Made of combination of integrated-circuit microchips and film circuitry. Temperature-sensing chips scanned at speeds approaching 10 kHz. Operating range minus 40 degrees C to 120 degrees C. Flexibility of array conforms to curved surfaces. Multiplexer eliminates numerous monitoring cables. Control of acquisition and recording of data effected by connecting array to microcomputers via suitable interface circuitry.

Development of plasma bolometers using fiber-optic temperature sensors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Reinke, M. L., E-mail: reinkeml@ornl.gov; Han, M.; Liu, G.

Measurements of radiated power in magnetically confined plasmas are important for exhaust studies in present experiments and expected to be a critical diagnostic for future fusion reactors. Resistive bolometer sensors have long been utilized in tokamaks and helical devices but suffer from electromagnetic interference (EMI). Results are shown from initial testing of a new bolometer concept based on fiber-optic temperature sensor technology. A small, 80 μm diameter, 200 μm long silicon pillar attached to the end of a single mode fiber-optic cable acts as a Fabry–Pérot cavity when broadband light, λ{sub o} ∼ 1550 nm, is transmitted along the fiber.more » Changes in temperature alter the optical path length of the cavity primarily through the thermo-optic effect, resulting in a shift of fringes reflected from the pillar detected using an I-MON 512 OEM spectrometer. While initially designed for use in liquids, this sensor has ideal properties for use as a plasma bolometer: a time constant, in air, of ∼150 ms, strong absorption in the spectral range of plasma emission, immunity to local EMI, and the ability to measure changes in temperature remotely. Its compact design offers unique opportunities for integration into the vacuum environment in places unsuitable for a resistive bolometer. Using a variable focus 5 mW, 405 nm, modulating laser, the signal to noise ratio versus power density of various bolometer technologies are directly compared, estimating the noise equivalent power density (NEPD). Present tests show the fiber-optic bolometer to have NEPD of 5-10 W/m{sup 2} when compared to those of the resistive bolometer which can achieve <0.5 W/m{sup 2} in the laboratory, but this can degrade to 1-2 W/m{sup 2} or worse when installed on a tokamak. Concepts are discussed to improve the signal to noise ratio of this new fiber-optic bolometer by reducing the pillar height and adding thin metallic coatings, along with improving the spectral resolution of the

Development of plasma bolometers using fiber-optic temperature sensors

NASA Astrophysics Data System (ADS)

Reinke, M. L.; Han, M.; Liu, G.; van Eden, G. G.; Evenblij, R.; Haverdings, M.; Stratton, B. C.

2016-11-01

Measurements of radiated power in magnetically confined plasmas are important for exhaust studies in present experiments and expected to be a critical diagnostic for future fusion reactors. Resistive bolometer sensors have long been utilized in tokamaks and helical devices but suffer from electromagnetic interference (EMI). Results are shown from initial testing of a new bolometer concept based on fiber-optic temperature sensor technology. A small, 80 μm diameter, 200 μm long silicon pillar attached to the end of a single mode fiber-optic cable acts as a Fabry-Pérot cavity when broadband light, λo ˜ 1550 nm, is transmitted along the fiber. Changes in temperature alter the optical path length of the cavity primarily through the thermo-optic effect, resulting in a shift of fringes reflected from the pillar detected using an I-MON 512 OEM spectrometer. While initially designed for use in liquids, this sensor has ideal properties for use as a plasma bolometer: a time constant, in air, of ˜150 ms, strong absorption in the spectral range of plasma emission, immunity to local EMI, and the ability to measure changes in temperature remotely. Its compact design offers unique opportunities for integration into the vacuum environment in places unsuitable for a resistive bolometer. Using a variable focus 5 mW, 405 nm, modulating laser, the signal to noise ratio versus power density of various bolometer technologies are directly compared, estimating the noise equivalent power density (NEPD). Present tests show the fiber-optic bolometer to have NEPD of 5-10 W/m2 when compared to those of the resistive bolometer which can achieve <0.5 W/m2 in the laboratory, but this can degrade to 1-2 W/m2 or worse when installed on a tokamak. Concepts are discussed to improve the signal to noise ratio of this new fiber-optic bolometer by reducing the pillar height and adding thin metallic coatings, along with improving the spectral resolution of the interrogator.

Temperature effects on polymer-carbon composite sensors

NASA Technical Reports Server (NTRS)

Lim, J. R.; Homer, M. L.; Manatt, K.; Kisor, A.; Lara, L.; Jewell, A. D.; Shevade, A.; Ryan, M. A.

2003-01-01

At JPL we have investigated the effects of temperature on polymer-carbon black composite sensors. While the electrical properties of polymer composites have been studied, with mechanisms of conductivity described by connectivity and tunneling, it is not fully understood how these properties affect sensor characteristics and responses.

46 CFR 153.565 - Special requirement for temperature sensors.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 46 Shipping 5 2011-10-01 2011-10-01 false Special requirement for temperature sensors. 153.565... CARGOES SHIPS CARRYING BULK LIQUID, LIQUEFIED GAS, OR COMPRESSED GAS HAZARDOUS MATERIALS Design and Equipment Special Requirements § 153.565 Special requirement for temperature sensors. If a cargo listed in...

46 CFR 153.565 - Special requirement for temperature sensors.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 46 Shipping 5 2010-10-01 2010-10-01 false Special requirement for temperature sensors. 153.565... CARGOES SHIPS CARRYING BULK LIQUID, LIQUEFIED GAS, OR COMPRESSED GAS HAZARDOUS MATERIALS Design and Equipment Special Requirements § 153.565 Special requirement for temperature sensors. If a cargo listed in...

Substrate Integrated Waveguide (SIW)-Based Wireless Temperature Sensor for Harsh Environments.

PubMed

Tan, Qiulin; Guo, Yanjie; Zhang, Lei; Lu, Fei; Dong, Helei; Xiong, Jijun

2018-05-03

This paper presents a new wireless sensor structure based on a substrate integrated circular waveguide (SICW) for the temperature test in harsh environments. The sensor substrate material is 99% alumina ceramic, and the SICW structure is composed of upper and lower metal plates and a series of metal cylindrical sidewall vias. A rectangular aperture antenna integrated on the surface of the SICW resonator is used for electromagnetic wave transmission between the sensor and the external antenna. The resonant frequency of the temperature sensor decreases when the temperature increases, because the relative permittivity of the alumina ceramic increases with temperature. The temperature sensor presented in this paper was tested four times at a range of 30⁻1200 °C, and a broad band coplanar waveguide (CPW)-fed antenna was used as an interrogation antenna during the test process. The resonant frequency changed from 2.371 to 2.141 GHz as the temperature varied from 30 to 1200 °C, leading to a sensitivity of 0.197 MHz/°C. The quality factor of the sensor changed from 3444.6 to 35.028 when the temperature varied from 30 to 1000 °C.

An Annular Mechanical Temperature Compensation Structure for Gas-Sealed Capacitive Pressure Sensor

PubMed Central

Hao, Xiuchun; Jiang, Yonggang; Takao, Hidekuni; Maenaka, Kazusuke; Higuchi, Kohei

2012-01-01

A novel gas-sealed capacitive pressure sensor with a temperature compensation structure is reported. The pressure sensor is sealed by Au-Au diffusion bonding under a nitrogen ambient with a pressure of 100 kPa and integrated with a platinum resistor-based temperature sensor for human activity monitoring applications. The capacitance-pressure and capacitance-temperature characteristics of the gas-sealed capacitive pressure sensor without temperature compensation structure are calculated. It is found by simulation that a ring-shaped structure on the diaphragm of the pressure sensor can mechanically suppress the thermal expansion effect of the sealed gas in the cavity. Pressure sensors without/with temperature compensation structures are fabricated and measured. Through measured results, it is verified that the calculation model is accurate. Using the compensation structures with a 900 μm inner radius, the measured temperature coefficient is much reduced as compared to that of the pressure sensor without compensation. The sensitivities of the pressure sensor before and after compensation are almost the same in the pressure range from 80 kPa to 100 kPa. PMID:22969385

Measurement of air exchange rates in different indoor environments using continuous CO2 sensors.

PubMed

You, Yan; Niu, Can; Zhou, Jian; Liu, Yating; Bai, Zhipeng; Zhang, Jiefeng; He, Fei; Zhang, Nan

2012-01-01

A new air exchange rate (AER) monitoring method using continuous CO2 sensors was developed and validated through both laboratory experiments and field studies. Controlled laboratory simulation tests were conducted in a 1-m3 environmental chamber at different AERs (0.1-10.0 hr(-1)). AERs were determined using the decay method based on box model assumptions. Field tests were conducted in classrooms, dormitories, meeting rooms and apartments during 2-5 weekdays using CO2 sensors coupled with data loggers. Indoor temperature, relative humidity (RH), and CO2 concentrations were continuously monitored while outdoor parameters combined with on-site climate conditions were recorded. Statistical results indicated that good laboratory performance was achieved: duplicate precision was within 10%, and the measured AERs were 90%-120% of the real AERs. Average AERs were 1.22, 1.37, 1.10, 1.91 and 0.73 hr(-1) in dormitories, air-conditioned classrooms, classrooms with an air circulation cooling system, reading rooms, and meeting rooms, respectively. In an elderly particulate matter exposure study, all the homes had AER values ranging from 0.29 to 3.46 hr(-1) in fall, and 0.12 to 1.39 hr(-1) in winter with a median AER of 1.15.

Effects of air temperature and discharge on Upper Mississippi River summer water temperatures

USGS Publications Warehouse

Gray, Brian R.; Robertson, Dale M.; Rogala, James T.

2018-01-01

Recent interest in the potential effects of climate change has prompted studies of air temperature and precipitation associations with water temperatures in rivers and streams. We examined associations between summer surface water temperatures and both air temperature and discharge for 5 reaches of the Upper Mississippi River during 1994–2011. Water–air temperature associations at a given reach approximated 1:1 when estimated under an assumption of reach independence but declined to approximately 1:2 when water temperatures were permitted to covary among reaches and were also adjusted for upstream air temperatures. Estimated water temperature–discharge associations were weak. An apparently novel feature of this study is that of addressing changes in associations between water and air temperatures when both are correlated among reaches.

A surface acoustic wave ICP sensor with good temperature stability.

PubMed

Zhang, Bing; Hu, Hong; Ye, Aipeng; Zhang, Peng

2017-07-20

Intracranial pressure (ICP) monitoring is very important for assessing and monitoring hydrocephalus, head trauma and hypertension patients, which could lead to elevated ICP or even devastating neurological damage. The mortality rate due to these diseases could be reduced through ICP monitoring, because precautions can be taken against the brain damage. This paper presents a surface acoustic wave (SAW) pressure sensor to realize ICP monitoring, which is capable of wireless and passive transmission with antenna attached. In order to improve the temperature stability of the sensor, two methods were adopted. First, the ST cut quartz was chosen as the sensor substrate due to its good temperature stability. Then, a differential temperature compensation method was proposed to reduce the effects of temperature. Two resonators were designed based on coupling of mode (COM) theory and the prototype was fabricated and verified using a system established for testing pressure and temperature. The experiment result shows that the sensor has a linearity of 2.63% and hysteresis of 1.77%. The temperature stability of the sensor has been greatly improved by using the differential compensation method, which validates the effectiveness of the proposed method.

A Study of a QCM Sensor Based on TiO2 Nanostructures for the Detection of NO2 and Explosives Vapours in Air

PubMed Central

Procek, Marcin; Stolarczyk, Agnieszka; Pustelny, Tadeusz; Maciak, Erwin

2015-01-01

The paper deals with investigations concerning the construction of sensors based on a quartz crystal microbalance (QCM) containing a TiO2 nanostructures sensor layer. A chemical method of synthesizing these nanostructures is presented. The prepared prototype of the QCM sensing system, as well as the results of tests for detecting low NO2 concentrations in an atmosphere of synthetic air have been described. The constructed NO2 sensors operate at room temperature, which is a great advantage, because resistance sensors based on wide gap semiconductors often require much higher operation temperatures, sometimes as high as 500 °C. The sensors constructed by the authors can be used, among other applications, in medical and chemical diagnostics, and also for the purpose of detecting explosive vapours. Reactions of the sensor to nitroglycerine vapours are presented as an example of its application. The influence of humidity on the operation of the sensor was studied. PMID:25912352

Calibration of low-cost gas sensors for an urban air quality monitoring network

NASA Astrophysics Data System (ADS)

Scott, A.; Kelley, C.; He, C.; Ghugare, P.; Lehman, A.; Benish, S.; Stratton, P.; Dickerson, R. R.; Zuidema, C.; Azdoud, Y.; Ren, X.

2017-12-01

In a warming world, environmental pollution may be exacerbated by anthropogenic activities, such as climate change and the urban heat island effect, as well as natural phenomena such as heat waves. However, monitoring air pollution at federal reference standards (approximately 1 part per billion or ppb for ambient ozone) is cost-prohibitive in heterogeneous urban areas as many expensive devices are required to fully capture a region's geo-spatial variability. Innovation in low-cost sensors provide a potential solution, yet technical challenges remain to overcome possible imprecision in the data. We present the calibrations of ozone and nitrous dioxide from a low-cost air quality monitoring device designed for the Baltimore Open Air Project. The sensors used in this study are commercially available thin film electrochemical sensors from SPEC Sensor, which are amperometric, meaning they generate current proportional to volumetric fraction of gas. The results of sensor calibrations in the laboratory and field are presented.

Recent Improvement of Medical Optical Fibre Pressure and Temperature Sensors.

PubMed

Poeggel, Sven; Duraibabu, Dineshbabu; Kalli, Kyriacos; Leen, Gabriel; Dooly, Gerard; Lewis, Elfed; Kelly, Jimmy; Munroe, Maria

2015-07-13

This investigation describes a detailed analysis of the fabrication and testing of optical fibre pressure and temperature sensors (OFPTS). The optical sensor of this research is based on an extrinsic Fabry-Perot interferometer (EFPI) with integrated fibre Bragg grating (FBG) for simultaneous pressure and temperature measurements. The sensor is fabricated exclusively in glass and with a small diameter of 0.2 mm, making it suitable for volume-restricted bio-medical applications. Diaphragm shrinking techniques based on polishing, hydrofluoric (HF) acid and femtosecond (FS) laser micro-machining are described and analysed. The presented sensors were examined carefully and demonstrated a pressure sensitivity in the range of sp = 2-10 nm/kPa and a resolution of better than ΔP = 10 Pa protect (0.1 cm H2O). A static pressure test in 38 cm H2O shows no drift of the sensor in a six-day period. Additionally, a dynamic pressure analysis demonstrated that the OFPTS never exceeded a drift of more than 130 Pa (1.3 cm H2O) in a 12-h measurement, carried out in a cardiovascular simulator. The temperature sensitivity is given by k = 10.7 pm/K, which results in a temperature resolution of better than ΔT = 0.1 K. Since the temperature sensing element is placed close to the pressure sensing element, the pressure sensor is insensitive to temperature changes.

Recent Improvement of Medical Optical Fibre Pressure and Temperature Sensors

PubMed Central

Poeggel, Sven; Duraibabu, Dineshbabu; Kalli, Kyriacos; Leen, Gabriel; Dooly, Gerard; Lewis, Elfed; Kelly, Jimmy; Munroe, Maria

2015-01-01

This investigation describes a detailed analysis of the fabrication and testing of optical fibre pressure and temperature sensors (OFPTS). The optical sensor of this research is based on an extrinsic Fabry–Perot interferometer (EFPI) with integrated fibre Bragg grating (FBG) for simultaneous pressure and temperature measurements. The sensor is fabricated exclusively in glass and with a small diameter of 0.2 mm, making it suitable for volume-restricted bio-medical applications. Diaphragm shrinking techniques based on polishing, hydrofluoric (HF) acid and femtosecond (FS) laser micro-machining are described and analysed. The presented sensors were examined carefully and demonstrated a pressure sensitivity in the range of sp = 2–10 nmkPa and a resolution of better than ΔP = 10 Pa (0.1 cm H2O). A static pressure test in 38 cmH2O shows no drift of the sensor in a six-day period. Additionally, a dynamic pressure analysis demonstrated that the OFPTS never exceeded a drift of more than 130 Pa (1.3 cm H2O) in a 12-h measurement, carried out in a cardiovascular simulator. The temperature sensitivity is given by k=10.7 pmK, which results in a temperature resolution of better than ΔT = 0.1 K. Since the temperature sensing element is placed close to the pressure sensing element, the pressure sensor is insensitive to temperature changes. PMID:26184331

Cooperative implementation of a high temperature acoustic sensor

NASA Technical Reports Server (NTRS)

Baldini, S. E.; Nowakowski, Edward; Smith, Herbert G.; Friebele, E. J.; Putnam, Martin A.; Rogowski, Robert; Melvin, Leland D.; Claus, Richard O.; Tran, Tuan; Holben, Milford S., Jr.

1991-01-01

The current status and results of a cooperative program aimed at the implementation of a high-temperature acoustic/strain sensor onto metallic structures are reported. The sensor systems that are to be implemented under this program will measure thermal expansion, maneuver loads, aircraft buffet, sonic fatigue, and acoustic emissions in environments that approach 1800 F. The discussion covers fiber development, fabrication of an extrinsic Fabry-Perot interferometer acoustic sensor, sensor mounting/integration, and results of an evaluation of the sensor capabilities.

A novel method of temperature compensation for piezoresistive microcantilever-based sensors.

PubMed

Han, Jianqiang; Wang, Xiaofei; Yan, Tianhong; Li, Yan; Song, Meixuan

2012-03-01

Microcantilever with integrated piezoresistor has been applied to in situ surface stress measurement in the field of biochemical sensors. It is well known that piezoresistive cantilever-based sensors are sensitive to ambient temperature changing due to highly temperature-dependent piezoresistive effect and mismatch in thermal expansion of composite materials. This paper proposes a novel method of temperature drift compensation for microcantilever-based sensors with a piezoresistive full Wheatstone bridge integrated at the clamped ends by subtracting the amplified output voltage of the reference cantilever from the output voltage of the sensing cantilever through a simple temperature compensating circuit. Experiments show that the temperature drift of microcantilever sensors can be significantly reduced by the method.

High-temperature fiber-optic Fabry-Perot interferometric sensors.

PubMed

Ding, Wenhui; Jiang, Yi; Gao, Ran; Liu, Yuewu

2015-05-01

A photonic crystal fiber (PCF) based high-temperature fiber-optic sensor is proposed and experimentally demonstrated. The sensor head is a Fabry-Perot cavity manufactured with a short section of endless single-mode photonic crystal fiber (ESM PCF). The interferometric spectrum of the Fabry-Perot interferometer is collected by a charge coupled device linear array based micro spectrometer. A high-resolution demodulation algorithm is used to interrogate the peak wavelengths. Experimental results show that the temperature range of 1200 °C and the temperature resolution of 1 °C are achieved.

High-temperature fiber-optic Fabry-Perot interferometric sensors

NASA Astrophysics Data System (ADS)

Ding, Wenhui; Jiang, Yi; Gao, Ran; Liu, Yuewu

2015-05-01

A photonic crystal fiber (PCF) based high-temperature fiber-optic sensor is proposed and experimentally demonstrated. The sensor head is a Fabry-Perot cavity manufactured with a short section of endless single-mode photonic crystal fiber (ESM PCF). The interferometric spectrum of the Fabry-Perot interferometer is collected by a charge coupled device linear array based micro spectrometer. A high-resolution demodulation algorithm is used to interrogate the peak wavelengths. Experimental results show that the temperature range of 1200 °C and the temperature resolution of 1 °C are achieved.

TiO2 gas sensor to detect the propanol at room temperature

NASA Astrophysics Data System (ADS)

Gaidan, Ibrahim; Asbia, Salim; Brabazon, Dermot; Ahad, Inam Ul

2017-10-01

Titanium dioxide (TiO2) was used as raw material to create sensing materials for gas sensor applications. The sample was mixed with isopropanol and wet-ball milled for 24 hours and then dried at 120°C to evaporate the solvent. Twenty grams of the dried powder was then pressed at 2 tons (27.58 MPa) using a pellet die. The pellet was heated at 1250°C in air for 5 hours and then milled for 10 minutes to powder form using a Gy-RO Mill machine. FIB and SEM analysis were used to study the microstructure of the materials. The polyvinyl butyral (5 wt.%) was used as a binder, while ethylenglycolmonobutylether served as a solvent to make a suitable paste. The paste was screen-printed on top of an alumina substrate that had copper electrodes to form the sensor. The sensor was used to detect propanol at room temperature over two different ranges (500 to 3000 ppm and 2500 to 5000 ppm). It was observed that the response of the device increased proportionally with increasing gas concentration repeatability.

Optical Fiber High Temperature Sensor Instrumentation for Energy Intensive Industries

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cooper, Kristie L.; Wang, Anbo; Pickrell, Gary R.

2006-11-14

This report summarizes technical progress during the program “Optical Fiber High Temperature Sensor Instrumentation for Energy Intensive Industries”, performed by the Center for Photonics Technology of the Bradley Department of Electrical and Computer Engineering at Virginia Tech. The objective of this program was to use technology recently invented at Virginia Tech to develop and demonstrate the application of self-calibrating optical fiber temperature and pressure sensors to several key energy-intensive industries where conventional, commercially available sensors exhibit greatly abbreviated lifetimes due primarily to environmental degradation. A number of significant technologies were developed under this program, including • a laser bonded silicamore » high temperature fiber sensor with a high temperature capability up to 700°C and a frequency response up to 150 kHz, • the world’s smallest fiber Fabry-Perot high temperature pressure sensor (125 x 20 μm) with 700°C capability, • UV-induced intrinsic Fabry-Perot interferometric sensors for distributed measurement, • a single crystal sapphire fiber-based sensor with a temperature capability up to 1600°C. These technologies have been well demonstrated and laboratory tested. Our work plan included conducting major field tests of these technologies at EPRI, Corning, Pratt & Whitney, and Global Energy; field validation of the technology is critical to ensuring its usefulness to U.S. industries. Unfortunately, due to budget cuts, DOE was unable to follow through with its funding commitment to support Energy Efficiency Science Initiative projects and this final phase was eliminated.« less

Nighttime Infrared radiative cooling and opacity inferred by REMS Ground Temperature Sensor Measurements

NASA Astrophysics Data System (ADS)

Martín-Torres, Javier; Paz Zorzano, María; Pla-García, Jorge; Rafkin, Scot; Lepinette, Alain; Sebastián, Eduardo; Gómez-Elvira, Javier; REMS Team

2013-04-01

Due to the low density of the Martian atmosphere, the temperature of the surface is controlled primarily by solar heating, and infrared cooling to the atmosphere and space, rather than heat exchange with the atmosphere. In the absence of solar radiation the infrared (IR) cooling, and then the nighttime surface temperatures, are directly controlled by soil termal inertia and atmospheric optical thickness (τ) at infrared wavelengths. Under non-wind conditions, and assuming no processes involving latent heat changes in the surface, for a particular site where the rover stands the main parameter controlling the IR cooling will be τ. The minimal ground temperature values at a fixed position may thus be used to detect local variations in the total dust/aerosols/cloud tickness. The Ground Temperature Sensor (GTS) and Air Temperature Sensor (ATS) in the Rover Environmental Monitoring Station (REMS) on board the Mars Science Laboratory (MSL) Curiosity rover provides hourly ground and air temperature measurements respectively. During the first 100 sols of operation of the rover, within the area of low thermal inertia, the minimal nightime ground temperatures reached values between 180 K and 190 K. For this season the expected frost point temperature is 200 K. Variations of up to 10 K have been observed associated with dust loading at Gale at the onset of the dust season. We will use these measurements together with line-by-line radiative transfer simulations using the Full Transfer By Optimized LINe-by-line (FUTBOLIN) code [Martín-Torres and Mlynczak, 2005] to estimate the IR atmospheric opacity and then dust/cloud coverage over the rover during the course of the MSL mission. Monitoring the dust loading and IR nightime cooling evolution during the dust season will allow for a better understanding of the influence of the atmosphere on the ground temperature and provide ground truth to models and orbiter measurements. References Martín-Torres, F. J. and M. G. Mlynczak

Clustering approaches to improve the performance of low cost air pollution sensors.

PubMed

Smith, Katie R; Edwards, Peter M; Evans, Mathew J; Lee, James D; Shaw, Marvin D; Squires, Freya; Wilde, Shona; Lewis, Alastair C

2017-08-24

Low cost air pollution sensors have substantial potential for atmospheric research and for the applied control of pollution in the urban environment, including more localized warnings to the public. The current generation of single-chemical gas sensors experience degrees of interference from other co-pollutants and have sensitivity to environmental factors such as temperature, wind speed and supply voltage. There are uncertainties introduced also because of sensor-to-sensor response variability, although this is less well reported. The sensitivity of Metal Oxide Sensors (MOS) to volatile organic compounds (VOCs) changed with relative humidity (RH) by up to a factor of five over the range of 19-90% RH and with an uncertainty in the correction of a factor of two at any given RH. The short-term (second to minute) stabilities of MOS and electrochemical CO sensor responses were reasonable. During more extended use, inter-sensor quantitative comparability was degraded due to unpredictable variability in individual sensor responses (to either measurand or interference or both) drifting over timescales of several hours to days. For timescales longer than a week identical sensors showed slow, often downwards, drifts in their responses which diverged across six CO sensors by up to 30% after two weeks. The measurement derived from the median sensor within clusters of 6, 8 and up to 21 sensors was evaluated against individual sensor performance and external reference values. The clustered approach maintained the cost competitiveness of a sensor device, but the median concentration from the ensemble of sensor signals largely eliminated the randomised hour-to-day response drift seen in individual sensors and excluded the effects of small numbers of poorly performing sensors that drifted significantly over longer time periods. The results demonstrate that for individual sensors to be optimally comparable to one another, and to reference instruments, they would likely require

Air temperature gradient in large industrial hall

NASA Astrophysics Data System (ADS)

Karpuk, Michał; Pełech, Aleksander; Przydróżny, Edward; Walaszczyk, Juliusz; Szczęśniak, Sylwia

2017-11-01

In the rooms with dominant sensible heat load, volume airflow depends on many factors incl. pre-established temperature difference between exhaust and supply airflow. As the temperature difference is getting higher, airflow volume drops down, consequently, the cost of AHU is reduced. In high industrial halls with air exhaust grids located under the ceiling additional temperature gradient above working zone should be taken into consideration. In this regard, experimental research of the vertical air temperature gradient in high industrial halls were carried out for the case of mixing ventilation system The paper presents the results of air temperature distribution measurements in high technological hall (mechanically ventilated) under significant sensible heat load conditions. The supply airflow was delivered to the hall with the help of the swirl diffusers while exhaust grids were located under the hall ceiling. Basing on the air temperature distribution measurements performed on the seven pre-established levels, air temperature gradient in the area between 2.0 and 7.0 m above the floor was calculated and analysed.

Portable air quality sensor unit for participatory monitoring: an end-to-end VESNA-AQ based prototype

NASA Astrophysics Data System (ADS)

Vucnik, Matevz; Robinson, Johanna; Smolnikar, Miha; Kocman, David; Horvat, Milena; Mohorcic, Mihael

2015-04-01

Key words: portable air quality sensor, CITI-SENSE, participatory monitoring, VESNA-AQ The emergence of low-cost easy to use portable air quality sensors units is opening new possibilities for individuals to assess their exposure to air pollutants at specific place and time, and share this information through the Internet connection. Such portable sensors units are being used in an ongoing citizen science project called CITI-SENSE, which enables citizens to measure and share the data. The project aims through creating citizens observatories' to empower citizens to contribute to and participate in environmental governance, enabling them to support and influence community and societal priorities as well as associated decision making. An air quality measurement system based on VESNA sensor platform was primarily designed within the project for the use as portable sensor unit in selected pilot cities (Belgrade, Ljubljana and Vienna) for monitoring outdoor exposure to pollutants. However, functionally the same unit with different set of sensors could be used for example as an indoor platform. The version designed for the pilot studies was equipped with the following sensors: NO2, O3, CO, temperature, relative humidity, pressure and accelerometer. The personal sensor unit is battery powered and housed in a plastic box. The VESNA-based air quality (AQ) monitoring system comprises the VESNA-AQ portable sensor unit, a smartphone app and the remote server. Personal sensor unit supports wireless connection to an Android smartphone via built-in Wi-Fi. The smartphone in turn serves also as the communication gateway towards the remote server using any of available data connections. Besides the gateway functionality the role of smartphone is to enrich data coming from the personal sensor unit with the GPS location, timestamps and user defined context. This, together with an accelerometer, enables the user to better estimate ones exposure in relation to physical activities, time

Air Pollution Monitoring and Mining Based on Sensor Grid in London

PubMed Central

Ma, Yajie; Richards, Mark; Ghanem, Moustafa; Guo, Yike; Hassard, John

2008-01-01

In this paper, we present a distributed infrastructure based on wireless sensors network and Grid computing technology for air pollution monitoring and mining, which aims to develop low-cost and ubiquitous sensor networks to collect real-time, large scale and comprehensive environmental data from road traffic emissions for air pollution monitoring in urban environment. The main informatics challenges in respect to constructing the high-throughput sensor Grid are discussed in this paper. We present a two-layer network framework, a P2P e-Science Grid architecture, and the distributed data mining algorithm as the solutions to address the challenges. We simulated the system in TinyOS to examine the operation of each sensor as well as the networking performance. We also present the distributed data mining result to examine the effectiveness of the algorithm. PMID:27879895

Tropospheric Airborne Meteorological Data Reporting (TAMDAR) Icing Sensor Performance During the 2003 Alliance Icing Research Study (AIRS II)

NASA Technical Reports Server (NTRS)

Murray, John J.; Schaffner, Philip R.; Minnis, Patrick; Nguyen, Louis; Delnore, Victor E.; Daniels, Taumi S.; Grainger, C. A.; Delene, D.; Wolff, C. A.

2004-01-01

The Tropospheric Airborne Meteorological Data Reporting (TAMDAR) sensor was deployed onboard the University of North Dakota Citation II aircraft in the Alliance Icing Research Study (AIRS II) from Nov 19 through December 14, 2003. TAMDAR is designed to measure and report winds, temperature, humidity, turbulence and icing from regional commercial aircraft (Daniels et. al., 2004). TAMDAR icing sensor performance is compared to a) in situ validation data from the Citation II sensor suite, b) Current Icing Potential products developed by the National Center for Atmospheric Research (NCAR) and available operationally on the NOAA Aviation Weather Center s Aviation Digital Data Server (ADDS) and c) NASA Advanced Satellite Aviation-weather Products (ASAP) cloud microphysical products.

Temperature compensated and self-calibrated current sensor using reference current

DOEpatents

Yakymyshyn, Christopher Paul [Seminole, FL; Brubaker, Michael Allen [Loveland, CO; Yakymyshyn, Pamela Jane [Seminole, FL

2008-01-22

A method is described to provide temperature compensation and self-calibration of a current sensor based on a plurality of magnetic field sensors positioned around a current carrying conductor. A reference electrical current carried by a conductor positioned within the sensing window of the current sensor is used to correct variations in the output signal due to temperature variations and aging.

Node-to-node field calibration of wireless distributed air pollution sensor network.

PubMed

Kizel, Fadi; Etzion, Yael; Shafran-Nathan, Rakefet; Levy, Ilan; Fishbain, Barak; Bartonova, Alena; Broday, David M

2018-02-01

Low-cost air quality sensors offer high-resolution spatiotemporal measurements that can be used for air resources management and exposure estimation. Yet, such sensors require frequent calibration to provide reliable data, since even after a laboratory calibration they might not report correct values when they are deployed in the field, due to interference with other pollutants, as a result of sensitivity to environmental conditions and due to sensor aging and drift. Field calibration has been suggested as a means for overcoming these limitations, with the common strategy involving periodical collocations of the sensors at an air quality monitoring station. However, the cost and complexity involved in relocating numerous sensor nodes back and forth, and the loss of data during the repeated calibration periods make this strategy inefficient. This work examines an alternative approach, a node-to-node (N2N) calibration, where only one sensor in each chain is directly calibrated against the reference measurements and the rest of the sensors are calibrated sequentially one against the other while they are deployed and collocated in pairs. The calibration can be performed multiple times as a routine procedure. This procedure minimizes the total number of sensor relocations, and enables calibration while simultaneously collecting data at the deployment sites. We studied N2N chain calibration and the propagation of the calibration error analytically, computationally and experimentally. The in-situ N2N calibration is shown to be generic and applicable for different pollutants, sensing technologies, sensor platforms, chain lengths, and sensor order within the chain. In particular, we show that chain calibration of three nodes, each calibrated for a week, propagate calibration errors that are similar to those found in direct field calibration. Hence, N2N calibration is shown to be suitable for calibration of distributed sensor networks. Copyright © 2017 Elsevier Ltd. All

Quasidistributed temperature sensor based on dense wavelength-division multiplexing optical fiber delay

NASA Astrophysics Data System (ADS)

Su, Jun; Yang, Ning; Fan, Zhiqiang; Qiu, Qi

2017-10-01

We report on a fiber-optic delay-based quasidistributed temperature sensor with high precision. The device works by detecting the delay induced by the temperature instead of the spectrum. To analyze the working principle of this sensor, the thermal dependence of the fiber-optic delay was theoretically investigated and the delay-temperature coefficient was measured to be 42.2 ps/km°C. In this sensor, quasidistributed measurement of temperature could be easily realized by dense wavelength-division multiplexing and wavelength addressing. We built and tested a prototype quasidistributed temperature sensor with eight testing points equally distributed along a 32.61-km-long fiber. The experimental results demonstrate an average error of <0.1°C. These results prove that this quasidistributed temperature sensor is feasible and that it is a viable option for simple and economic temperature measurements.

Development of a fiber optic high temperature strain sensor

NASA Technical Reports Server (NTRS)

Rausch, E. O.; Murphy, K. E.; Brookshire, S. P.

1992-01-01

From 1 Apr. 1991 to 31 Aug. 1992, the Georgia Tech Research Institute conducted a research program to develop a high temperature fiber optic strain sensor as part of a measurement program for the space shuttle booster rocket motor. The major objectives of this program were divided into four tasks. Under Task 1, the literature on high-temperature fiber optic strain sensors was reviewed. Task 2 addressed the design and fabrication of the strain sensor. Tests and calibration were conducted under Task 3, and Task 4 was to generate recommendations for a follow-on study of a distributed strain sensor. Task 4 was submitted to NASA as a separate proposal.

Analysis, compensation, and correction of temperature effects on FBG strain sensors

NASA Astrophysics Data System (ADS)

Haber, T. C.; Ferguson, S.; Guthrie, D.; Graver, T. W.; Soller, B. J.; Mendez, Alexis

2013-05-01

One of the most common fiber optic sensor (FOS) types used are fiber Bragg gratings (FBG), and the most frequently measured parameter is strain. Hence, FBG strain sensors are one of the most prevalent FOS devices in use today in structural sensing and monitoring in civil engineering, aerospace, marine, oil and gas, composites and smart structure applications. However, since FBGs are simultaneously sensitive to both temperature and strain, it becomes essential to utilize sensors that are either fully temperature insensitive or, alternatively, properly temperature compensated to avoid erroneous measurements. In this paper, we introduce the concept of measured "total strain", which is inherent and unique to optical strain sensors. We review and analyze the temperature and strain sensitivities of FBG strain sensors and decompose the total measured strain into thermal and non-thermal components. We explore the differences between substrate CTE and System Thermal Response Coefficients, which govern the type and quality of thermal strain decomposition analysis. Finally, we present specific guidelines to achieve proper temperature-insensitive strain measurements by combining adequate installation, sensor packaging and data correction techniques.

Noncontact Measurement of Humidity and Temperature Using Airborne Ultrasound

NASA Astrophysics Data System (ADS)

Kon, Akihiko; Mizutani, Koichi; Wakatsuki, Naoto

2010-04-01

We describe a noncontact method for measuring humidity and dry-bulb temperature. Conventional humidity sensors are single-point measurement devices, so that a noncontact method for measuring the relative humidity is required. Ultrasonic temperature sensors are noncontact measurement sensors. Because water vapor in the air increases sound velocity, conventional ultrasonic temperature sensors measure virtual temperature, which is higher than dry-bulb temperature. We performed experiments using an ultrasonic delay line, an atmospheric pressure sensor, and either a thermometer or a relative humidity sensor to confirm the validity of our measurement method at relative humidities of 30, 50, 75, and 100% and at temperatures of 283.15, 293.15, 308.15, and 323.15 K. The results show that the proposed method measures relative humidity with an error rate of less than 16.4% and dry-bulb temperature with an error of less than 0.7 K. Adaptations of the measurement method for use in air-conditioning control systems are discussed.

Temperature compensated and self-calibrated current sensor using reference magnetic field

DOEpatents

Yakymyshyn, Christopher Paul; Brubaker, Michael Allen; Yakymyshyn, Pamela Jane

2007-10-09

A method is described to provide temperature compensation and self-calibration of a current sensor based on a plurality of magnetic field sensors positioned around a current carrying conductor. A reference magnetic field generated within the current sensor housing is detected by the magnetic field sensors and is used to correct variations in the output signal due to temperature variations and aging.

No-reheat air-conditioning

NASA Technical Reports Server (NTRS)

Obler, H. D.

1980-01-01

Air conditioning system, for environmentally controlled areas containing sensitive equipment, regulates temperature and humidity without wasteful and costly reheating. System blends outside air with return air as dictated by various sensors to ensure required humidity in cooled spaces (such as computer room).

A Novel High-Sensitivity, Low-Power, Liquid Crystal Temperature Sensor

PubMed Central

Algorri, José Francisco; Urruchi, Virginia; Bennis, Noureddine; Sánchez-Pena, José Manuel

2014-01-01

A novel temperature sensor based on nematic liquid crystal permittivity as a sensing magnitude, is presented. This sensor consists of a specific micrometric structure that gives considerable advantages from other previous related liquid crystal (LC) sensors. The analytical study reveals that permittivity change with temperature is introduced in a hyperbolic cosine function, increasing the sensitivity term considerably. The experimental data has been obtained for ranges from −6 °C to 100 °C. Despite this, following the LC datasheet, theoretical ranges from −40 °C to 109 °C could be achieved. These results have revealed maximum sensitivities of 33 mVrms/°C for certain temperature ranges; three times more than of most silicon temperature sensors. As it was predicted by the analytical study, the micrometric size of the proposed structure produces a high output voltage. Moreover the voltage's sensitivity to temperature response can be controlled by the applied voltage. This response allows temperature measurements to be carried out without any amplification or conditioning circuitry, with very low power consumption. PMID:24721771

14 CFR 23.1157 - Carburetor air temperature controls.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Carburetor air temperature controls. 23... Powerplant Powerplant Controls and Accessories § 23.1157 Carburetor air temperature controls. There must be a separate carburetor air temperature control for each engine. ...

14 CFR 23.1157 - Carburetor air temperature controls.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Carburetor air temperature controls. 23... Powerplant Powerplant Controls and Accessories § 23.1157 Carburetor air temperature controls. There must be a separate carburetor air temperature control for each engine. ...

14 CFR 23.1157 - Carburetor air temperature controls.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Carburetor air temperature controls. 23... Powerplant Powerplant Controls and Accessories § 23.1157 Carburetor air temperature controls. There must be a separate carburetor air temperature control for each engine. ...

14 CFR 23.1157 - Carburetor air temperature controls.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Carburetor air temperature controls. 23... Powerplant Powerplant Controls and Accessories § 23.1157 Carburetor air temperature controls. There must be a separate carburetor air temperature control for each engine. ...

14 CFR 23.1157 - Carburetor air temperature controls.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Carburetor air temperature controls. 23... Powerplant Powerplant Controls and Accessories § 23.1157 Carburetor air temperature controls. There must be a separate carburetor air temperature control for each engine. ...

A Novel Intra-body Sensor for Vaginal Temperature Monitoring

PubMed Central

Rodrigues, Joel J. P. C.; Caldeira, João; Vaidya, Binod

2009-01-01

Over the years some medical studies have tried to better understand the internal behavior of human beings. Many researchers in this domain have been striving to find relationships between intra-vaginal temperature and certain female health conditions, such as ovulation and fertile period since woman’s intra-vaginal temperature is one of the body parameters most preferred in such studies. However, due to lack of a appropriate technology, medical research devoted to studying correlations of such body parameters with certain womans’ body phenomena could not obtain better results. This article presents the design and implementation of a novel intra-body sensor for acquisition and monitoring of intra-vaginal temperatures. This novel intra-body sensor provides data collection that is used for studying the relation between temperature variations and female health conditions, such as anticipation and monitoring of the ovulation period, detection of pregnancy contractions, preterm labor prevention, etc.. The motivation for this work focuses on the development of this new intra-body sensor that will represent a major step in medical technology. The novel sensor was tested and validated on hospitalized women as well as normal healthy women. Finally our medical team has attested to the accuracy, usability and performance of this novel intra-body sensor. PMID:22574046

Fiber-Optic Temperature Sensor Using a Thin-Film Fabry-Perot Interferometer

NASA Technical Reports Server (NTRS)

Beheim, Glenn

1997-01-01

A fiber-optic temperature sensor was developed that is rugged, compact, stable, and can be inexpensively fabricated. This thin-film interferometric temperature sensor was shown to be capable of providing a +/- 2 C accuracy over the range of -55 to 275 C, throughout a 5000 hr operating life. A temperature-sensitive thin-film Fabry-Perot interferometer can be deposited directly onto the end of a multimode optical fiber. This batch-fabricatable sensor can be manufactured at a much lower cost than can a presently available sensor, which requires the mechanical attachment of a Fabry-Perot interferometer to a fiber. The principal disadvantage of the thin-film sensor is its inherent instability, due to the low processing temperatures that must be used to prevent degradation of the optical fiber's buffer coating. The design of the stable thin-film temperature sensor considered the potential sources of both short and long term drifts. The temperature- sensitive Fabry-Perot interferometer was a silicon film with a thickness of approx. 2 microns. A laser-annealing process was developed which crystallized the silicon film without damaging the optical fiber. The silicon film was encapsulated with a thin layer of Si3N4 over coated with aluminum. Crystallization of the silicon and its encapsulation with a highly stable, impermeable thin-film structure were essential steps in producing a sensor with the required long-term stability.

Brain temperature measurement: A study of in vitro accuracy and stability of smart catheter temperature sensors.

PubMed

Li, Chunyan; Wu, Pei-Ming; Wu, Zhizhen; Ahn, Chong H; LeDoux, David; Shutter, Lori A; Hartings, Jed A; Narayan, Raj K

2012-02-01

The injured brain is vulnerable to increases in temperature after severe head injury. Therefore, accurate and reliable measurement of brain temperature is important to optimize patient outcome. In this work, we have fabricated, optimized and characterized temperature sensors for use with a micromachined smart catheter for multimodal intracranial monitoring. Developed temperature sensors have resistance of 100.79 ± 1.19Ω and sensitivity of 67.95 mV/°C in the operating range from15-50°C, and time constant of 180 ms. Under the optimized excitation current of 500 μA, adequate signal-to-noise ratio was achieved without causing self-heating, and changes in immersion depth did not introduce clinically significant errors of measurements (<0.01°C). We evaluated the accuracy and long-term drift (5 days) of twenty temperature sensors in comparison to two types of commercial temperature probes (USB Reference Thermometer, NIST-traceable bulk probe with 0.05°C accuracy; and IT-21, type T type clinical microprobe with guaranteed 0.1°C accuracy) under controlled laboratory conditions. These in vitro experimental data showed that the temperature measurement performance of our sensors was accurate and reliable over the course of 5 days. The smart catheter temperature sensors provided accuracy and long-term stability comparable to those of commercial tissue-implantable microprobes, and therefore provide a means for temperature measurement in a microfabricated, multimodal cerebral monitoring device.

Silicon-Etalon Fiber-Optic Temperature Sensor

NASA Technical Reports Server (NTRS)

Beheim, Glenn; Fritsch, Klaus; Flatico, Joseph M.; Azar, Massood Tabib

1993-01-01

Developmental temperature sensor consists of silicon Fabry-Perot etalon attached to end of optical fiber. Features immunity to electrical interference, small size, light weight, safety, and chemical inertness. Output encoded in ration of intensities at two different wavelengths, rather than in overall intensity, with result that temperature readings not degraded much by changes in transmittance of fiber-optic link.

Fiber-optic temperature sensor using a spectrum-modulating semiconductor etalon

NASA Technical Reports Server (NTRS)

Beheim, Glenn; Anthan, Donald J.; Beheim, Glenn; Anthan, Donald J.

1987-01-01

Described is a fiber-optic temperature sensor that uses a spectrum modulating SiC etalon. The spectral output of this type of sensor may be analyzed to obtain a temperature measurement which is largely independent of the transmission properties of the sensor's fiber-optic link. A highly precise laboratory spectrometer is described in detail, and this instrument is used to study the properties of this type of sensor. Also described are a number of different spectrum analyzers that are more suitable for use in a practical thermometer.

In situ monitoring of temperature inside lithium-ion batteries by flexible micro temperature sensors.

PubMed

Lee, Chi-Yuan; Lee, Shuo-Jen; Tang, Ming-Shao; Chen, Pei-Chi

2011-01-01

Lithium-ion secondary batteries are commonly used in electric vehicles, smart phones, personal digital assistants (PDA), notebooks and electric cars. These lithium-ion secondary batteries must charge and discharge rapidly, causing the interior temperature to rise quickly, raising a safety issue. Over-charging results in an unstable voltage and current, causing potential safety problems, such as thermal runaways and explosions. Thus, a micro flexible temperature sensor for the in in-situ monitoring of temperature inside a lithium-ion secondary battery must be developed. In this work, flexible micro temperature sensors were integrated into a lithium-ion secondary battery using the micro-electro-mechanical systems (MEMS) process for monitoring temperature in situ.

40 CFR 91.309 - Engine intake air temperature measurement.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 40 Protection of Environment 20 2014-07-01 2013-07-01 true Engine intake air temperature... Provisions § 91.309 Engine intake air temperature measurement. (a) Engine intake air temperature measurement... the supply system or in the air stream entering the engine. (b) The temperature measurements must be...

40 CFR 91.309 - Engine intake air temperature measurement.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 40 Protection of Environment 21 2012-07-01 2012-07-01 false Engine intake air temperature... Provisions § 91.309 Engine intake air temperature measurement. (a) Engine intake air temperature measurement... the supply system or in the air stream entering the engine. (b) The temperature measurements must be...

40 CFR 91.309 - Engine intake air temperature measurement.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 40 Protection of Environment 21 2013-07-01 2013-07-01 false Engine intake air temperature... Provisions § 91.309 Engine intake air temperature measurement. (a) Engine intake air temperature measurement... the supply system or in the air stream entering the engine. (b) The temperature measurements must be...

40 CFR 91.309 - Engine intake air temperature measurement.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 20 2011-07-01 2011-07-01 false Engine intake air temperature... Provisions § 91.309 Engine intake air temperature measurement. (a) Engine intake air temperature measurement... the supply system or in the air stream entering the engine. (b) The temperature measurements must be...

14 CFR 29.1157 - Carburetor air temperature controls.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Carburetor air temperature controls. 29.1157 Section 29.1157 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF... Accessories § 29.1157 Carburetor air temperature controls. There must be a separate carburetor air temperature...

14 CFR 25.1157 - Carburetor air temperature controls.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Carburetor air temperature controls. 25.1157 Section 25.1157 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF... Accessories § 25.1157 Carburetor air temperature controls. There must be a separate carburetor air temperature...

14 CFR 29.1157 - Carburetor air temperature controls.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Carburetor air temperature controls. 29.1157 Section 29.1157 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF... Accessories § 29.1157 Carburetor air temperature controls. There must be a separate carburetor air temperature...

14 CFR 25.1157 - Carburetor air temperature controls.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Carburetor air temperature controls. 25.1157 Section 25.1157 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF... Accessories § 25.1157 Carburetor air temperature controls. There must be a separate carburetor air temperature...

14 CFR 29.1157 - Carburetor air temperature controls.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Carburetor air temperature controls. 29... TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Powerplant Powerplant Controls and Accessories § 29.1157 Carburetor air temperature controls. There must be a separate carburetor air temperature...

14 CFR 25.1157 - Carburetor air temperature controls.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Carburetor air temperature controls. 25... TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY AIRPLANES Powerplant Powerplant Controls and Accessories § 25.1157 Carburetor air temperature controls. There must be a separate carburetor air temperature...

14 CFR 29.1157 - Carburetor air temperature controls.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Carburetor air temperature controls. 29.1157 Section 29.1157 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF... Accessories § 29.1157 Carburetor air temperature controls. There must be a separate carburetor air temperature...

14 CFR 29.1157 - Carburetor air temperature controls.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Carburetor air temperature controls. 29.1157 Section 29.1157 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF... Accessories § 29.1157 Carburetor air temperature controls. There must be a separate carburetor air temperature...

14 CFR 25.1157 - Carburetor air temperature controls.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Carburetor air temperature controls. 25.1157 Section 25.1157 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF... Accessories § 25.1157 Carburetor air temperature controls. There must be a separate carburetor air temperature...