High-temperature optical fiber instrumentation for gas flow monitoring in gas turbine engines

NASA Astrophysics Data System (ADS)

Roberts, Adrian; May, Russell G.; Pickrell, Gary R.; Wang, Anbo

2002-02-01

In the design and testing of gas turbine engines, real-time data about such physical variables as temperature, pressure and acoustics are of critical importance. The high temperature environment experienced in the engines makes conventional electronic sensors devices difficult to apply. Therefore, there is a need for innovative sensors that can reliably operate under the high temperature conditions and with the desirable resolution and frequency response. A fiber optic high temperature sensor system for dynamic pressure measurement is presented in this paper. This sensor is based on a new sensor technology - the self-calibrated interferometric/intensity-based (SCIIB) sensor, recently developed at Virginia Tech. State-of-the-art digital signal processing (DSP) methods are applied to process the signal from the sensor to acquire high-speed frequency response.

A Tactile Sensor Network System Using a Multiple Sensor Platform with a Dedicated CMOS-LSI for Robot Applications †

PubMed Central

Shao, Chenzhong; Tanaka, Shuji; Nakayama, Takahiro; Hata, Yoshiyuki; Bartley, Travis; Muroyama, Masanori

2017-01-01

Robot tactile sensation can enhance human–robot communication in terms of safety, reliability and accuracy. The final goal of our project is to widely cover a robot body with a large number of tactile sensors, which has significant advantages such as accurate object recognition, high sensitivity and high redundancy. In this study, we developed a multi-sensor system with dedicated Complementary Metal-Oxide-Semiconductor (CMOS) Large-Scale Integration (LSI) circuit chips (referred to as “sensor platform LSI”) as a framework of a serial bus-based tactile sensor network system. The sensor platform LSI supports three types of sensors: an on-chip temperature sensor, off-chip capacitive and resistive tactile sensors, and communicates with a relay node via a bus line. The multi-sensor system was first constructed on a printed circuit board to evaluate basic functions of the sensor platform LSI, such as capacitance-to-digital and resistance-to-digital conversion. Then, two kinds of external sensors, nine sensors in total, were connected to two sensor platform LSIs, and temperature, capacitive and resistive sensing data were acquired simultaneously. Moreover, we fabricated flexible printed circuit cables to demonstrate the multi-sensor system with 15 sensor platform LSIs operating simultaneously, which showed a more realistic implementation in robots. In conclusion, the multi-sensor system with up to 15 sensor platform LSIs on a bus line supporting temperature, capacitive and resistive sensing was successfully demonstrated. PMID:29061954

A Tactile Sensor Network System Using a Multiple Sensor Platform with a Dedicated CMOS-LSI for Robot Applications.

PubMed

Shao, Chenzhong; Tanaka, Shuji; Nakayama, Takahiro; Hata, Yoshiyuki; Bartley, Travis; Nonomura, Yutaka; Muroyama, Masanori

2017-08-28

Robot tactile sensation can enhance human-robot communication in terms of safety, reliability and accuracy. The final goal of our project is to widely cover a robot body with a large number of tactile sensors, which has significant advantages such as accurate object recognition, high sensitivity and high redundancy. In this study, we developed a multi-sensor system with dedicated Complementary Metal-Oxide-Semiconductor (CMOS) Large-Scale Integration (LSI) circuit chips (referred to as "sensor platform LSI") as a framework of a serial bus-based tactile sensor network system. The sensor platform LSI supports three types of sensors: an on-chip temperature sensor, off-chip capacitive and resistive tactile sensors, and communicates with a relay node via a bus line. The multi-sensor system was first constructed on a printed circuit board to evaluate basic functions of the sensor platform LSI, such as capacitance-to-digital and resistance-to-digital conversion. Then, two kinds of external sensors, nine sensors in total, were connected to two sensor platform LSIs, and temperature, capacitive and resistive sensing data were acquired simultaneously. Moreover, we fabricated flexible printed circuit cables to demonstrate the multi-sensor system with 15 sensor platform LSIs operating simultaneously, which showed a more realistic implementation in robots. In conclusion, the multi-sensor system with up to 15 sensor platform LSIs on a bus line supporting temperature, capacitive and resistive sensing was successfully demonstrated.

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.

Design of an Embedded CMOS Temperature Sensor for Passive RFID Tag Chips.

PubMed

Deng, Fangming; He, Yigang; Li, Bing; Zhang, Lihua; Wu, Xiang; Fu, Zhihui; Zuo, Lei

2015-05-18

This paper presents an ultra-low embedded power temperature sensor for passive RFID tags. The temperature sensor converts the temperature variation to a PTAT current, which is then transformed into a temperature-controlled frequency. A phase locked loop (PLL)-based sensor interface is employed to directly convert this temperature-controlled frequency into a corresponding digital output without an external reference clock. The fabricated sensor occupies an area of 0.021 mm2 using the TSMC 0.18 1P6M mixed-signal CMOS process. Measurement results of the embedded sensor within the tag system shows a 92 nW power dissipation under 1.0 V supply voltage at room temperature, with a sensing resolution of 0.15 °C/LSB and a sensing accuracy of -0.7/0.6 °C from -30 °C to 70 °C after 1-point calibration at 30 °C.

Design of an Embedded CMOS Temperature Sensor for Passive RFID Tag Chips

PubMed Central

Deng, Fangming; He, Yigang; Li, Bing; Zhang, Lihua; Wu, Xiang; Fu, Zhihui; Zuo, Lei

2015-01-01

This paper presents an ultra-low embedded power temperature sensor for passive RFID tags. The temperature sensor converts the temperature variation to a PTAT current, which is then transformed into a temperature-controlled frequency. A phase locked loop (PLL)-based sensor interface is employed to directly convert this temperature-controlled frequency into a corresponding digital output without an external reference clock. The fabricated sensor occupies an area of 0.021 mm2 using the TSMC 0.18 1P6M mixed-signal CMOS process. Measurement results of the embedded sensor within the tag system shows a 92 nW power dissipation under 1.0 V supply voltage at room temperature, with a sensing resolution of 0.15 °C/LSB and a sensing accuracy of −0.7/0.6 °C from −30 °C to 70 °C after 1-point calibration at 30 °C. PMID:25993518

Accurate Behavioral Simulator of All-Digital Time-Domain Smart Temperature Sensors by Using SIMULINK

PubMed Central

Chen, Chun-Chi; Chen, Chao-Lieh; Lin, You-Ting

2016-01-01

This study proposes a new behavioral simulator that uses SIMULINK for all-digital CMOS time-domain smart temperature sensors (TDSTSs) for performing rapid and accurate simulations. Inverter-based TDSTSs offer the benefits of low cost and simple structure for temperature-to-digital conversion and have been developed. Typically, electronic design automation tools, such as HSPICE, are used to simulate TDSTSs for performance evaluations. However, such tools require extremely long simulation time and complex procedures to analyze the results and generate figures. In this paper, we organize simple but accurate equations into a temperature-dependent model (TDM) by which the TDSTSs evaluate temperature behavior. Furthermore, temperature-sensing models of a single CMOS NOT gate were devised using HSPICE simulations. Using the TDM and these temperature-sensing models, a novel simulator in SIMULINK environment was developed to substantially accelerate the simulation and simplify the evaluation procedures. Experiments demonstrated that the simulation results of the proposed simulator have favorable agreement with those obtained from HSPICE simulations, showing that the proposed simulator functions successfully. This is the first behavioral simulator addressing the rapid simulation of TDSTSs. PMID:27509507

A self-timed multipurpose delay sensor for Field Programmable Gate Arrays (FPGAs).

PubMed

Osuna, Carlos Gómez; Ituero, Pablo; López-Vallejo, Marisa

2013-12-20

This paper presents a novel self-timed multi-purpose sensor especially conceived for Field Programmable Gate Arrays (FPGAs). The aim of the sensor is to measure performance variations during the life-cycle of the device, such as process variability, critical path timing and temperature variations. The proposed topology, through the use of both combinational and sequential FPGA elements, amplifies the time of a signal traversing a delay chain to produce a pulse whose width is the sensor's measurement. The sensor is fully self-timed, avoiding the need for clock distribution networks and eliminating the limitations imposed by the system clock. One single off- or on-chip time-to-digital converter is able to perform digitization of several sensors in a single operation. These features allow for a simplified approach for designers wanting to intertwine a multi-purpose sensor network with their application logic. Employed as a temperature sensor, it has been measured to have an error of  ±0.67 °C, over the range of 20-100 °C, employing 20 logic elements with a 2-point calibration.

A Self-Timed Multipurpose Delay Sensor for Field Programmable Gate Arrays (FPGAs)

PubMed Central

Osuna, Carlos Gómez; Ituero, Pablo; López-Vallejo, Marisa

2014-01-01

This paper presents a novel self-timed multi-purpose sensor especially conceived for Field Programmable Gate Arrays (FPGAs). The aim of the sensor is to measure performance variations during the life-cycle of the device, such as process variability, critical path timing and temperature variations. The proposed topology, through the use of both combinational and sequential FPGA elements, amplifies the time of a signal traversing a delay chain to produce a pulse whose width is the sensor's measurement. The sensor is fully self-timed, avoiding the need for clock distribution networks and eliminating the limitations imposed by the system clock. One single off- or on-chip time-to-digital converter is able to perform digitization of several sensors in a single operation. These features allow for a simplified approach for designers wanting to intertwine a multi-purpose sensor network with their application logic. Employed as a temperature sensor, it has been measured to have an error of ±0.67 °C, over the range of 20–100 °C, employing 20 logic elements with a 2-point calibration. PMID:24361927

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.

Development of an inherently digital transducer

NASA Technical Reports Server (NTRS)

Richard, R. R.

1972-01-01

The term digital transducer normally implies the combination of conventional analog sensors with encoders or analog-to-digital converters. Because of the objectionable characteristics of most digital transducers, a program was instituted to investigate the possibility of producing a transducer that is inherently digital, instead of a transducer that is digital in the usual sense. Such a device would have improved accuracy and reliability and would have reduced power and bulk requirements because two processes, sensing and conditioning, would be combined into one processes. A Curie-point-temperature sensor is described that represents realization of the stated goal. Also, a metal-insulator semiconductor is described that does not conform precisely to the program goals but that appears to have applications as a new and interesting transduction device.

In Situ Monitoring of Temperature inside Lithium-Ion Batteries by Flexible Micro Temperature Sensors

PubMed Central

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. PMID:22163735

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.

A highly sensitive CMOS digital Hall sensor for low magnetic field applications.

PubMed

Xu, Yue; Pan, Hong-Bin; He, Shu-Zhuan; Li, Li

2012-01-01

Integrated CMOS Hall sensors have been widely used to measure magnetic fields. However, they are difficult to work with in a low magnetic field environment due to their low sensitivity and large offset. This paper describes a highly sensitive digital Hall sensor fabricated in 0.18 μm high voltage CMOS technology for low field applications. The sensor consists of a switched cross-shaped Hall plate and a novel signal conditioner. It effectively eliminates offset and low frequency 1/f noise by applying a dynamic quadrature offset cancellation technique. The measured results show the optimal Hall plate achieves a high current related sensitivity of about 310 V/AT. The whole sensor has a remarkable ability to measure a minimum ± 2 mT magnetic field and output a digital Hall signal in a wide temperature range from -40 °C to 120 °C.

Sensing Challenges for Controls and PHM in the Hostile Operating Conditions of Modern Turbine Engine (Postprint)

DTIC Science & Technology

2008-07-01

SUBJECT TERMS Gas turbine, sensors, Hostile Operating Conditions, FADEC , High Temperature Regimes for Sensors, Sensor Needs, Turbine Engine...Authority Digital Engine Control ( FADEC ). The frequency and bandwidth capability of sensors for engine control are drastically different for each sensor...metering valve assembly is responsive to electrical signals generated by the FADEC in response to sensors that measure turbine speed, pressure

Self-correcting electronically scanned pressure sensor

NASA Technical Reports Server (NTRS)

Gross, C. (Inventor)

1983-01-01

A multiple channel high data rate pressure sensing device is disclosed for use in wind tunnels, spacecraft, airborne, process control, automotive, etc., pressure measurements. Data rates in excess of 100,000 measurements per second are offered with inaccuracies from temperature shifts less than 0.25% (nominal) of full scale over a temperature span of 55 C. The device consists of thirty-two solid state sensors, signal multiplexing electronics to electronically address each sensor, and digital electronic circuitry to automatically correct the inherent thermal shift errors of the pressure sensors and their associated electronics.

Wearable sweat detector device design for health monitoring and clinical diagnosis

NASA Astrophysics Data System (ADS)

Wu, Qiuchen; Zhang, Xiaodong; Tian, Bihao; Zhang, Hongyan; Yu, Yang; Wang, Ming

2017-06-01

Miniaturized sensor is necessary part for wearable detector for biomedical applications. Wearable detector device is indispensable for online health care. This paper presents a concept of an wearable digital health monitoring device design for sweat analysis. The flexible sensor is developed to quantify the amount of hydrogen ions in sweat and skin temperature in real time. The detection system includes pH sensor, temperature sensor, signal processing module, power source, microprocessor, display module and so on. The sweat monitoring device is designed for sport monitoring or clinical diagnosis.

Variable self-powered light detection CMOS chip with real-time adaptive tracking digital output based on a novel on-chip sensor.

PubMed

Wang, HongYi; Fan, Youyou; Lu, Zhijian; Luo, Tao; Fu, Houqiang; Song, Hongjiang; Zhao, Yuji; Christen, Jennifer Blain

2017-10-02

This paper provides a solution for a self-powered light direction detection with digitized output. Light direction sensors, energy harvesting photodiodes, real-time adaptive tracking digital output unit and other necessary circuits are integrated on a single chip based on a standard 0.18 µm CMOS process. Light direction sensors proposed have an accuracy of 1.8 degree over a 120 degree range. In order to improve the accuracy, a compensation circuit is presented for photodiodes' forward currents. The actual measurement precision of output is approximately 7 ENOB. Besides that, an adaptive under voltage protection circuit is designed for variable supply power which may undulate with temperature and process.

Digital control of diode laser for atmospheric spectroscopy

NASA Technical Reports Server (NTRS)

Menzies, R. T.; Rutledge, C. W. (Inventor)

1985-01-01

A system is described for remote absorption spectroscopy of trace species using a diode laser tunable over a useful spectral region of 50 to 200 cm(-1) by control of diode laser temperature over range from 15 K to 100 K, and tunable over a smaller region of typically 0.1 to 10 cm(-1) by control of the diode laser current over a range from 0 to 2 amps. Diode laser temperature and current set points are transmitted to the instrument in digital form and stored in memory for retrieval under control of a microprocessor during measurements. The laser diode current is determined by a digital to analog converter through a field effect transistor for a high degree of ambient temperature stability, while the laser diode temperature is determined by set points entered into a digital to analog converter under control of the microprocessor. Temperature of the laser diode is sensed by a sensor diode to provide negative feedback to the temperature control circuit that responds to the temperature control digital to analog converter.

A Self-Sustained Wireless Multi-Sensor Platform Integrated with Printable Organic Sensors for Indoor Environmental Monitoring

PubMed Central

Wu, Chun-Chang; Chuang, Wen-Yu; Wu, Ching-Da; Su, Yu-Cheng; Huang, Yung-Yang; Huang, Yang-Jing; Peng, Sheng-Yu; Yu, Shih-An; Lin, Chih-Ting; Lu, Shey-Shi

2017-01-01

A self-sustained multi-sensor platform for indoor environmental monitoring is proposed in this paper. To reduce the cost and power consumption of the sensing platform, in the developed platform, organic materials of PEDOT:PSS and PEDOT:PSS/EB-PANI are used as the sensing films for humidity and CO2 detection, respectively. Different from traditional gas sensors, these organic sensing films can operate at room temperature without heating processes or infrared transceivers so that the power consumption of the developed humidity and the CO2 sensors can be as low as 10 μW and 5 μW, respectively. To cooperate with these low-power sensors, a Complementary Metal-Oxide-Semiconductor (CMOS) system-on-chip (SoC) is designed to amplify and to read out multiple sensor signals with low power consumption. The developed SoC includes an analog-front-end interface circuit (AFE), an analog-to-digital convertor (ADC), a digital controller and a power management unit (PMU). Scheduled by the digital controller, the sensing circuits are power gated with a small duty-cycle to reduce the average power consumption to 3.2 μW. The designed PMU converts the power scavenged from a dye sensitized solar cell (DSSC) module into required supply voltages for SoC circuits operation under typical indoor illuminance conditions. To our knowledge, this is the first multiple environmental parameters (Temperature/CO2/Humidity) sensing platform that demonstrates a true self-powering functionality for long-term operations. PMID:28353680

A Self-Sustained Wireless Multi-Sensor Platform Integrated with Printable Organic Sensors for Indoor Environmental Monitoring.

PubMed

Wu, Chun-Chang; Chuang, Wen-Yu; Wu, Ching-Da; Su, Yu-Cheng; Huang, Yung-Yang; Huang, Yang-Jing; Peng, Sheng-Yu; Yu, Shih-An; Lin, Chih-Ting; Lu, Shey-Shi

2017-03-29

A self-sustained multi-sensor platform for indoor environmental monitoring is proposed in this paper. To reduce the cost and power consumption of the sensing platform, in the developed platform, organic materials of PEDOT:PSS and PEDOT:PSS/EB-PANI are used as the sensing films for humidity and CO₂ detection, respectively. Different from traditional gas sensors, these organic sensing films can operate at room temperature without heating processes or infrared transceivers so that the power consumption of the developed humidity and the CO₂ sensors can be as low as 10 μW and 5 μW, respectively. To cooperate with these low-power sensors, a Complementary Metal-Oxide-Semiconductor (CMOS) system-on-chip (SoC) is designed to amplify and to read out multiple sensor signals with low power consumption. The developed SoC includes an analog-front-end interface circuit (AFE), an analog-to-digital convertor (ADC), a digital controller and a power management unit (PMU). Scheduled by the digital controller, the sensing circuits are power gated with a small duty-cycle to reduce the average power consumption to 3.2 μW. The designed PMU converts the power scavenged from a dye sensitized solar cell (DSSC) module into required supply voltages for SoC circuits operation under typical indoor illuminance conditions. To our knowledge, this is the first multiple environmental parameters (Temperature/CO₂/Humidity) sensing platform that demonstrates a true self-powering functionality for long-term operations.

Design and Theoretical Analysis of a Resonant Sensor for Liquid Density Measurement

PubMed Central

Zheng, Dezhi; Shi, Jiying; Fan, Shangchun

2012-01-01

In order to increase the accuracy of on-line liquid density measurements, a sensor equipped with a tuning fork as the resonant sensitive component is designed in this paper. It is a quasi-digital sensor with simple structure and high precision. The sensor is based on resonance theory and composed of a sensitive unit and a closed-loop control unit, where the sensitive unit consists of the actuator, the resonant tuning fork and the detector and the closed-loop control unit comprises precondition circuit, digital signal processing and control unit, analog-to-digital converter and digital-to-analog converter. An approximate parameters model of the tuning fork is established and the impact of liquid density, position of the tuning fork, temperature and structural parameters on the natural frequency of the tuning fork are also analyzed. On this basis, a tuning fork liquid density measurement sensor is developed. In addition, experimental testing on the sensor has been carried out on standard calibration facilities under constant 20 °C, and the sensor coefficients are calibrated. The experimental results show that the repeatability error is about 0.03% and the accuracy is about 0.4 kg/m3. The results also confirm that the method to increase the accuracy of liquid density measurement is feasible. PMID:22969378

Design and theoretical analysis of a resonant sensor for liquid density measurement.

PubMed

Zheng, Dezhi; Shi, Jiying; Fan, Shangchun

2012-01-01

In order to increase the accuracy of on-line liquid density measurements, a sensor equipped with a tuning fork as the resonant sensitive component is designed in this paper. It is a quasi-digital sensor with simple structure and high precision. The sensor is based on resonance theory and composed of a sensitive unit and a closed-loop control unit, where the sensitive unit consists of the actuator, the resonant tuning fork and the detector and the closed-loop control unit comprises precondition circuit, digital signal processing and control unit, analog-to-digital converter and digital-to-analog converter. An approximate parameters model of the tuning fork is established and the impact of liquid density, position of the tuning fork, temperature and structural parameters on the natural frequency of the tuning fork are also analyzed. On this basis, a tuning fork liquid density measurement sensor is developed. In addition, experimental testing on the sensor has been carried out on standard calibration facilities under constant 20 °C, and the sensor coefficients are calibrated. The experimental results show that the repeatability error is about 0.03% and the accuracy is about 0.4 kg/m(3). The results also confirm that the method to increase the accuracy of liquid density measurement is feasible.

Novel Concrete Temperature Monitoring Method Based on an Embedded Passive RFID Sensor Tag.

PubMed

Liu, Yongsheng; Deng, Fangming; He, Yigang; Li, Bing; Liang, Zhen; Zhou, Shuangxi

2017-06-22

This paper firstly introduces the importance of temperature control in concrete measurement, then a passive radio frequency identification (RFID) sensor tag embedded for concrete temperature monitoring is presented. In order to reduce the influences of concrete electromagnetic parameters during the drying process, a T-type antenna is proposed to measure the concrete temperature at the required depth. The proposed RFID sensor tag is based on the EPC generation-2 ultra-high frequency (UHF) communication protocol and operates in passive mode. The temperature sensor can convert the sensor signals to corresponding digital signals without an external reference clock due to the adoption of phase-locked loop (PLL)-based architecture. Laboratory experimentation and on-site testing demonstrate that our sensor tag embedded in concrete can provide reliable communication performance in passive mode. The maximum communicating distance between reader and tag is 7 m at the operating frequency of 915 MHz and the tested results show high consistency with the results tested by a thermocouple.

Novel Concrete Temperature Monitoring Method Based on an Embedded Passive RFID Sensor Tag

PubMed Central

Liu, Yongsheng; Deng, Fangming; He, Yigang; Li, Bing; Liang, Zhen; Zhou, Shuangxi

2017-01-01

This paper firstly introduces the importance of temperature control in concrete measurement, then a passive radio frequency identification (RFID) sensor tag embedded for concrete temperature monitoring is presented. In order to reduce the influences of concrete electromagnetic parameters during the drying process, a T-type antenna is proposed to measure the concrete temperature at the required depth. The proposed RFID sensor tag is based on the EPC generation-2 ultra-high frequency (UHF) communication protocol and operates in passive mode. The temperature sensor can convert the sensor signals to corresponding digital signals without an external reference clock due to the adoption of phase-locked loop (PLL)-based architecture. Laboratory experimentation and on-site testing demonstrate that our sensor tag embedded in concrete can provide reliable communication performance in passive mode. The maximum communicating distance between reader and tag is 7 m at the operating frequency of 915 MHz and the tested results show high consistency with the results tested by a thermocouple. PMID:28640188

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.

[Temperature Measurement with Bluetooth under Android Platform].

PubMed

Wang, Shuai; Shen, Hao; Luo, Changze

2015-03-01

To realize the real-time transmission of temperature data and display using the platform of intelligent mobile phone and bluetooth. Application of Arduino Uno R3 in temperature data acquisition of digital temperature sensor DS18B20 acquisition, through the HC-05 bluetooth transmits the data to the intelligent smart phone Android system, realizes transmission of temperature data. Using Java language to write applications program under Android development environment, can achieve real-time temperature data display, storage and drawing temperature fluctuations drawn graphics. Temperature sensor is experimentally tested to meet the body temperature measurement precision and accuracy. This paper can provide a reference for other smart phone mobile medical product development.

Investigation of the difficulties associated with the use of lead telluride and other II - IV compounds for thin film thermistors

NASA Technical Reports Server (NTRS)

Mclennan, W. D.

1975-01-01

The fabrication of thermistors was investigated for use as atmospheric temperature sensors in meteorological rocket soundings. The final configuration of the thin film thermistor is shown. The composition and primary functions of the six layers of the sensor are described. A digital controller for thin film deposition control is described which is capable of better than .1 A/sec rate control. The computer program modules for digital control of thin film deposition processing are included.

Evaluation of a Three-Channel High-Temperature Superconducting Magnetometer System

DTIC Science & Technology

1997-06-01

achieved by the best commercially available fluxgate magnetometers demonstrated to date and is only surpassed by low temperature superconducting...wire lines carry the analog SQUID magnetometer signal as well as dc power and ground, and the fiberoptic lines carry digital clock and data signals...with the magnetometers mounted on the three-sensor probe used in the sensor evaluated here. This probe is not highly stabilized with respect to the

Superconducting Digital Multiplexers for Sensor Arrays

NASA Technical Reports Server (NTRS)

Kadin, Alan M.; Brock, Darren K.; Gupta, Deepnarayan

2004-01-01

Arrays of cryogenic microbolometers and other cryogenic detectors are being developed for infrared imaging. If the signal from each sensor is amplified, multiplexed, and digitized using superconducting electronics, then this data can be efficiently read out to ambient temperature with a minimum of noise and thermal load. HYPRES is developing an integrated system based on SQUID amplifiers, a high-resolution analog-to-digital converter (ADC) based on RSFQ (rapid single flux quantum) logic, and a clocked RSFQ multiplexer. The ADC and SQUIDs have already been demonstrated for other projects, so this paper will focus on new results of a digital multiplexer. Several test circuits have been fabricated using Nb Josephson technology and are about to be tested at T = 4.2 K, with a more complete prototype in preparation.

Multimode fiber-optic temperature sensor system based on dual-wavelength difference absorption principle

NASA Astrophysics Data System (ADS)

Zhang, Zaixuan; Lin, Dan; Fang, Xiao; Jing, Shangzhong

1991-08-01

The multimode fiber optical temperature sensor system is a cobalt salt solution (CoCl26H2O) in the isoptopyl alcohol and water thermochromic transducer based on the dual-wavelength difference absorption principle. The digital locking-in detection, the operation of signal division and temperature calibration is operated by IBM PC computer. The measurement temperature range of the fiber-optic sensor system is 30 degree(s)C to 50 degree(s)C, accuracy is +/- 0.15 degree(s)C, and the temperature resolution is 0.02 degree(s)C. The most accurate measurements resulting from repeated stability tests over 6 and 12 hours (40 degree(s)C) are +/- $0.05 degree(s)C and +/- 0.18 degree(s)C, and the temperature mean is displayed in real time.

Possibilities of further improvement of 1 s fluxgate variometers

NASA Astrophysics Data System (ADS)

Marusenkov, Andriy

2017-08-01

The paper discusses the possibility of improving temperature and noise characteristics of fluxgate variometers. The new fluxgate sensor with a Co-based amorphous ring core is described. This sensor is capable of improving the signal-to-noise ratio at the recording short-period geomagnetic variations. Besides the sensor performance, it is very important to create the high-stability compensation field that cancels the main Earth magnetic field inside the magnetic cores. For this purpose the new digitally controlled current source with low noise level and high temperature stability is developed.

Integrating Fiber Optic Strain Sensors into Metal Using Ultrasonic Additive Manufacturing

NASA Astrophysics Data System (ADS)

Hehr, Adam; Norfolk, Mark; Wenning, Justin; Sheridan, John; Leser, Paul; Leser, Patrick; Newman, John A.

2018-03-01

Ultrasonic additive manufacturing, a rather new three-dimensional (3D) printing technology, uses ultrasonic energy to produce metallurgical bonds between layers of metal foils near room temperature. This low temperature attribute of the process enables integration of temperature sensitive components, such as fiber optic strain sensors, directly into metal structures. This may be an enabling technology for Digital Twin applications, i.e., virtual model interaction and feedback with live load data. This study evaluates the consolidation quality, interface robustness, and load sensing limits of commercially available fiber optic strain sensors embedded into aluminum alloy 6061. Lastly, an outlook on the technology and its applications is described.

Hydrophone Investigations of Earthquakes and Explosion Generated High-Frequency Seismic Phases

DTIC Science & Technology

1989-06-30

stacked along three axes, a temperature sensor , a 2- component tiltmeter , and floating point analog-to-digital electronics. It is clamped inside the... sensors within the ocean- sediment-basement column in order to maximize the signal-to-noise ratio and the signal fidelity of various seismic and acoustic...improved by siting the sensors below the ocean-sediment interface. These changes are especially pronounced on horizontal sensors . Although siting the

Thermal heat-balance mode flow-to-frequency converter

NASA Astrophysics Data System (ADS)

Pawlowski, Eligiusz

2016-11-01

This paper presents new type of thermal flow converter with the pulse frequency output. The integrating properties of the temperature sensor have been used, which allowed for realization of pulse frequency modulator with thermal feedback loop, stabilizing temperature of sensor placed in the flowing medium. The system assures balancing of heat amount supplied in impulses to the sensor and heat given up by the sensor in a continuous way to the flowing medium. Therefore the frequency of output impulses is proportional to the heat transfer coefficient from sensor to environment. According to the King's law, the frequency of those impulses is a function of medium flow velocity around the sensor. The special feature of presented solution is total integration of thermal sensor with the measurement signal conditioning system. Sensor and conditioning system are not the separate elements of the measurement circuit, but constitute a whole in form of thermal heat-balance mode flow-to-frequency converter. The advantage of such system is easiness of converting the frequency signal to the digital form, without using any additional analogue-to-digital converters. The frequency signal from the converter may be directly connected to the microprocessor input, which with use of standard built-in counters may convert the frequency into numerical value of high precision. Moreover, the frequency signal has higher resistance to interference than the voltage signal and may be transmitted to remote locations without the information loss.

Optical temperature compensation schemes of spectral modulation sensors for aircraft engine control

NASA Astrophysics Data System (ADS)

Berkcan, Ertugrul

1993-02-01

Optical temperature compensation schemes for the ratiometric interrogation of spectral modulation sensors for source temperature robustness are presented. We have obtained better than 50 - 100X decrease of the temperature coefficient of the sensitivity using these types of compensation. We have also developed a spectrographic interrogation scheme that provides increased source temperature robustness; this affords a significantly improved accuracy over FADEC temperature ranges as well as temperature coefficient of the sensitivity that is substantially and further reduced. This latter compensation scheme can be integrated in a small E/O package including the detection, analog and digital signal processing. We find that these interrogation schemes can be used within a detector spatially multiplexed architecture.

Interior Temperature Measurement Using Curved Mercury Capillary Sensor Based on X-ray Radiography

NASA Astrophysics Data System (ADS)

Chen, Shuyue; Jiang, Xing; Lu, Guirong

2017-07-01

A method was presented for measuring the interior temperature of objects using a curved mercury capillary sensor based on X-ray radiography. The sensor is composed of a mercury bubble, a capillary and a fixed support. X-ray digital radiography was employed to capture image of the mercury column in the capillary, and a temperature control system was designed for the sensor calibration. We adopted livewire algorithms and mathematical morphology to calculate the mercury length. A measurement model relating mercury length to temperature was established, and the measurement uncertainty associated with the mercury column length and the linear model fitted by least-square method were analyzed. To verify the system, the interior temperature measurement of an autoclave, which is totally closed, was taken from 29.53°C to 67.34°C. The experiment results show that the response of the system is approximately linear with an uncertainty of maximum 0.79°C. This technique provides a new approach to measure interior temperature of objects.

A microcomputer-based data acquisition system for ECG, body and ambient temperatures measurement during bathing.

PubMed

Uokawa, Y; Yonezawa, Y; Caldwell, W M; Hahn, A W

2000-01-01

A data acquisition system employing a low power 8 bit microcomputer has been developed for heart rate variability monitoring before, during and after bathing. The system consists of three integral chest electrodes, two temperature sensors, an instrumentation amplifier, a low power 8-bit single chip microcomputer (SMC) and a 4 MB compact flash memory (CFM). The ECG from the electrodes is converted to an 8-bit digital format at a 1 ms rate by an A/D converter in the SMC. Both signals from the body and ambient temperature sensors are converted to an 8-bit digital format every 1 second. These data are stored by the CFM. The system is powered by a rechargeable 3.6 V lithium battery. The 4 x 11 x 1 cm system is encapsulated in epoxy and silicone, yielding a total volume of 44 cc. The weight is 100 g.

600 C Logic Gates Using Silicon Carbide JFET's

NASA Technical Reports Server (NTRS)

Neudeck, Philip G.; Beheim, Glenn M.; Salupo, Carl S.a

2000-01-01

Complex electronics and sensors are increasingly being relied on to enhance the capabilities and efficiency of modernjet aircraft. Some of these electronics and sensors monitor and control vital engine components and aerosurfaces that operate at high temperatures above 300 C. However, since today's silicon-based electronics technology cannot function at such high temperatures, these electronics must reside in environmentally controlled areas. This necessitates either the use of long wire runs between sheltered electronics and hot-area sensors and controls, or the fuel cooling of electronics and sensors located in high-temperature areas. Both of these low-temperature-electronics approaches suffer from serious drawbacks in terms of increased weight, decreased fuel efficiency, and reduction of aircraft reliability. A family of high-temperature electronics and sensors that could function in hot areas would enable substantial aircraft performance gains. Especially since, in the future, some turbine-engine electronics may need to function at temperatures as high as 600 C. This paper reports the fabrication and demonstration of the first semiconductor digital logic gates ever to function at 600 C. Key obstacles blocking the realization of useful 600 C turbine engine integrated sensor and control electronics are outlined.

Design and Characterization of a Three-Axis Hall Effect-Based Soft Skin Sensor

PubMed Central

Tomo, Tito Pradhono; Somlor, Sophon; Schmitz, Alexander; Jamone, Lorenzo; Huang, Weijie; Kristanto, Harris; Sugano, Shigeki

2016-01-01

This paper presents an easy means to produce a 3-axis Hall effect–based skin sensor for robotic applications. It uses an off-the-shelf chip and is physically small and provides digital output. Furthermore, the sensor has a soft exterior for safe interactions with the environment; in particular it uses soft silicone with about an 8 mm thickness. Tests were performed to evaluate the drift due to temperature changes, and a compensation using the integral temperature sensor was implemented. Furthermore, the hysteresis and the crosstalk between the 3-axis measurements were evaluated. The sensor is able to detect minimal forces of about 1 gf. The sensor was calibrated and results with total forces up to 1450 gf in the normal and tangential directions of the sensor are presented. The test revealed that the sensor is able to measure the different components of the force vector. PMID:27070604

Design and Characterization of a Three-Axis Hall Effect-Based Soft Skin Sensor.

PubMed

Tomo, Tito Pradhono; Somlor, Sophon; Schmitz, Alexander; Jamone, Lorenzo; Huang, Weijie; Kristanto, Harris; Sugano, Shigeki

2016-04-07

This paper presents an easy means to produce a 3-axis Hall effect-based skin sensor for robotic applications. It uses an off-the-shelf chip and is physically small and provides digital output. Furthermore, the sensor has a soft exterior for safe interactions with the environment; in particular it uses soft silicone with about an 8 mm thickness. Tests were performed to evaluate the drift due to temperature changes, and a compensation using the integral temperature sensor was implemented. Furthermore, the hysteresis and the crosstalk between the 3-axis measurements were evaluated. The sensor is able to detect minimal forces of about 1 gf. The sensor was calibrated and results with total forces up to 1450 gf in the normal and tangential directions of the sensor are presented. The test revealed that the sensor is able to measure the different components of the force vector.

Digital pressure transducer for use at high temperatures

DOEpatents

Karplus, Henry H. B.

1981-01-01

A digital pressure sensor for measuring fluid pressures at relatively high temperatures includes an electrically conducting fiber coupled to the fluid by a force disc that causes tension in the fiber to be a function of fluid pressure. The tension causes changes in the mechanical resonant frequency of the fiber, which is caused to vibrate in a magnetic field to produce an electrical signal from a positive-feedback amplifier at the resonant frequency. A count of this frequency provides a measure of the fluid pressure.

Digital pressure transducer for use at high temperatures

DOEpatents

Karplus, H.H.B.

A digital pressure sensor for measuring fluid pressures at relatively high temperatures includes an electrically conducting fiber coupled to the fluid by a force disc that causes tension in the fiber to be a function of fluid pressure. The tension causes changes in the mechanical resonant frequency of the fiber, which is caused to vibrate in a magnetic field to produce an electrical signal from a positive-feedback amplifier at the resonant frequency. A count of this frequency provides a measure of the fluid pressure.

Multi-channel temperature measurement system for automotive battery stack

NASA Astrophysics Data System (ADS)

Lewczuk, Radoslaw; Wojtkowski, Wojciech

2017-08-01

A multi-channel temperature measurement system for monitoring of automotive battery stack is presented in the paper. The presented system is a complete battery temperature measuring system for hybrid / electric vehicles that incorporates multi-channel temperature measurements with digital temperature sensors communicating through 1-Wire buses, individual 1-Wire bus for each sensor for parallel computing (parallel measurements instead of sequential), FPGA device which collects data from sensors and translates it for CAN bus frames. CAN bus is incorporated for communication with car Battery Management System and uses additional CAN bus controller which communicates with FPGA device through SPI bus. The described system can parallel measure up to 12 temperatures but can be easily extended in the future in case of additional needs. The structure of the system as well as particular devices are described in the paper. Selected results of experimental investigations which show proper operation of the system are presented as well.

Smart image sensors: an emerging key technology for advanced optical measurement and microsystems

NASA Astrophysics Data System (ADS)

Seitz, Peter

1996-08-01

Optical microsystems typically include photosensitive devices, analog preprocessing circuitry and digital signal processing electronics. The advances in semiconductor technology have made it possible today to integrate all photosensitive and electronical devices on one 'smart image sensor' or photo-ASIC (application-specific integrated circuits containing photosensitive elements). It is even possible to provide each 'smart pixel' with additional photoelectronic functionality, without compromising the fill factor substantially. This technological capability is the basis for advanced cameras and optical microsystems showing novel on-chip functionality: Single-chip cameras with on- chip analog-to-digital converters for less than $10 are advertised; image sensors have been developed including novel functionality such as real-time selectable pixel size and shape, the capability of performing arbitrary convolutions simultaneously with the exposure, as well as variable, programmable offset and sensitivity of the pixels leading to image sensors with a dynamic range exceeding 150 dB. Smart image sensors have been demonstrated offering synchronous detection and demodulation capabilities in each pixel (lock-in CCD), and conventional image sensors are combined with an on-chip digital processor for complete, single-chip image acquisition and processing systems. Technological problems of the monolithic integration of smart image sensors include offset non-uniformities, temperature variations of electronic properties, imperfect matching of circuit parameters, etc. These problems can often be overcome either by designing additional compensation circuitry or by providing digital correction routines. Where necessary for technological or economic reasons, smart image sensors can also be combined with or realized as hybrids, making use of commercially available electronic components. It is concluded that the possibilities offered by custom smart image sensors will influence the design and the performance of future electronic imaging systems in many disciplines, reaching from optical metrology to machine vision on the factory floor and in robotics applications.

Spectrum-modulating fiber-optic sensors for aircraft control systems

NASA Technical Reports Server (NTRS)

Beheim, Glenn; Fritsch, Klaus

1987-01-01

A family of fiber-optic sensors for aircraft engine control systems is described. Each of these sensors uses a spectrum-modulation method to obtain an output which is largely independent of the fiber link transmissivity. A position encoder is described which uses a code plate to digitally modulate the sensor output spectrum. Also described are pressure and temperature sensors, each of which uses a Fabry-Perot cavity to modulate the sensor output spectrum as a continuous function of the measurand. A technique is described whereby a collection of these sensors may be effectively combined to perform a number of the measurements which are required by an aircraft-engine control system.

An NFC-Enabled CMOS IC for a Wireless Fully Implantable Glucose Sensor.

PubMed

DeHennis, Andrew; Getzlaff, Stefan; Grice, David; Mailand, Marko

2016-01-01

This paper presents an integrated circuit (IC) that merges integrated optical and temperature transducers, optical interface circuitry, and a near-field communication (NFC)-enabled digital, wireless readout for a fully passive implantable sensor platform to measure glucose in people with diabetes. A flip-chip mounted LED and monolithically integrated photodiodes serve as the transduction front-end to enable fluorescence readout. A wide-range programmable transimpedance amplifier adapts the sensor signals to the input of an 11-bit analog-to-digital converter digitizing the measurements. Measurement readout is enabled by means of wireless backscatter modulation to a remote NFC reader. The system is able to resolve current levels of less than 10 pA with a single fluorescent measurement energy consumption of less than 1 μJ. The wireless IC is fabricated in a 0.6-μm-CMOS process and utilizes a 13.56-MHz-based ISO15693 for passive wireless readout through a NFC interface. The IC is utilized as the core interface to a fluorescent, glucose transducer to enable a fully implantable sensor-based continuous glucose monitoring system.

Thermal infrared reference sources fabricated from low-cost components and materials

NASA Astrophysics Data System (ADS)

Hovland, Harald; Skauli, Torbjørn

2018-04-01

Mass markets, including mobile phones and automotive sensors, drive rapid developments of imaging technologies toward high performance, low cost sensors, even for the thermal infrared. Good infrared calibration blackbody sources have remained relatively costly, however. Here we demonstrate how to make low-cost reference sources, making quantitative infrared radiometry more accessible to a wider community. Our approach uses ordinary construction materials combined with low cost microcontrollers, digital temperature sensors and foil heater elements from massmarket 3D printers. Blackbodies are constructed from a foil heater of some chosen size and shape, attached to the back of a similarly shaped aluminum plate coated with commercial black paint, which normally exhibits high emissivity. The emissivity can be readily checked by using a thermal imager to view the reflection of a hot object. A digital temperature sensor is attached to the back of the plate. Thermal isolation of the backside minimizes temperature gradients through the plate, ensuring correct readings of the front temperature. The isolation also serves to minimize convection gradients and keeps power consumption low, which is useful for battery powered operation in the field. We demonstrate surface blackbodies (200x200 mm2) with surface homogeneities as low as 0.1°C at 100°C. Homogeneous heating and low thermal mass provides for fast settling time and setup/pack-down time. The approach is scalable to larger sizes by tiling, enabling portable and foldable square-meter-size or larger devices.

Automated Cryocooler Monitor and Control System

NASA Technical Reports Server (NTRS)

Britcliffe, Michael J.; Hanscon, Theodore R.; Fowler, Larry E.

2011-01-01

A system was designed to automate cryogenically cooled low-noise amplifier systems used in the NASA Deep Space Network. It automates the entire operation of the system including cool-down, warm-up, and performance monitoring. The system is based on a single-board computer with custom software and hardware to monitor and control the cryogenic operation of the system. The system provides local display and control, and can be operated remotely via a Web interface. The system controller is based on a commercial single-board computer with onboard data acquisition capability. The commercial hardware includes a microprocessor, an LCD (liquid crystal display), seven LED (light emitting diode) displays, a seven-key keypad, an Ethernet interface, 40 digital I/O (input/output) ports, 11 A/D (analog to digital) inputs, four D/A (digital to analog) outputs, and an external relay board to control the high-current devices. The temperature sensors used are commercial silicon diode devices that provide a non-linear voltage output proportional to temperature. The devices are excited with a 10-microamp bias current. The system is capable of monitoring and displaying three temperatures. The vacuum sensors are commercial thermistor devices. The output of the sensors is a non-linear voltage proportional to vacuum pressure in the 1-Torr to 1-millitorr range. Two sensors are used. One measures the vacuum pressure in the cryocooler and the other the pressure at the input to the vacuum pump. The helium pressure sensor is a commercial device that provides a linear voltage output from 1 to 5 volts, corresponding to a gas pressure from 0 to 3.5 MPa (approx. = 500 psig). Control of the vacuum process is accomplished with a commercial electrically operated solenoid valve. A commercial motor starter is used to control the input power of the compressor. The warm-up heaters are commercial power resistors sized to provide the appropriate power for the thermal mass of the particular system, and typically provide 50 watts of heat. There are four basic operating modes. "Cool " mode commands the system to cool to normal operating temperature. "Heat " mode is used to warm the device to a set temperature near room temperature. "Pump " mode is a maintenance function that allows the vacuum system to be operated alone to remove accumulated contaminants from the vacuum area. In "Off " mode, no power is applied to the system.

A linearization time-domain CMOS smart temperature sensor using a curvature compensation oscillator.

PubMed

Chen, Chun-Chi; Chen, Hao-Wen

2013-08-28

This paper presents an area-efficient time-domain CMOS smart temperature sensor using a curvature compensation oscillator for linearity enhancement with a -40 to 120 °C temperature range operability. The inverter-based smart temperature sensors can substantially reduce the cost and circuit complexity of integrated temperature sensors. However, a large curvature exists on the temperature-to-time transfer curve of the inverter-based delay line and results in poor linearity of the sensor output. For cost reduction and error improvement, a temperature-to-pulse generator composed of a ring oscillator and a time amplifier was used to generate a thermal sensing pulse with a sufficient width proportional to the absolute temperature (PTAT). Then, a simple but effective on-chip curvature compensation oscillator is proposed to simultaneously count and compensate the PTAT pulse with curvature for linearization. With such a simple structure, the proposed sensor possesses an extremely small area of 0.07 mm2 in a TSMC 0.35-mm CMOS 2P4M digital process. By using an oscillator-based scheme design, the proposed sensor achieves a fine resolution of 0.045 °C without significantly increasing the circuit area. With the curvature compensation, the inaccuracy of -1.2 to 0.2 °C is achieved in an operation range of -40 to 120 °C after two-point calibration for 14 packaged chips. The power consumption is measured as 23 mW at a sample rate of 10 samples/s.

An Implantable RFID Sensor Tag toward Continuous Glucose Monitoring.

PubMed

Xiao, Zhibin; Tan, Xi; Chen, Xianliang; Chen, Sizheng; Zhang, Zijian; Zhang, Hualei; Wang, Junyu; Huang, Yue; Zhang, Peng; Zheng, Lirong; Min, Hao

2015-05-01

This paper presents a wirelessly powered implantable electrochemical sensor tag for continuous blood glucose monitoring. The system is remotely powered by a 13.56-MHz inductive link and utilizes an ISO 15693 radio frequency identification (RFID) standard for communication. This paper provides reliable and accurate measurement for changing glucose level. The sensor tag employs a long-term glucose sensor, a winding ferrite antenna, an RFID front-end, a potentiostat, a 10-bit sigma-delta analog to digital converter, an on-chip temperature sensor, and a digital baseband for protocol processing and control. A high-frequency external reader is used to power, command, and configure the sensor tag. The only off-chip support circuitry required is a tuned antenna and a glucose microsensor. The integrated chip fabricated in SMIC 0.13-μm CMOS process occupies an area of 1.2 mm ×2 mm and consumes 50 μW. The power sensitivity of the whole system is -4 dBm. The sensor tag achieves a measured glucose range of 0-30 mM with a sensitivity of 0.75 nA/mM.

Fully Digital Arrays of Silicon Photomultipliers (dSiPM) - a Scalable Alternative to Vacuum Photomultiplier Tubes (PMT)

NASA Astrophysics Data System (ADS)

Haemisch, York; Frach, Thomas; Degenhardt, Carsten; Thon, Andreas

Silicon Photomultipliers (SiPMs) have emerged as promising alternative to fast vacuum photomultiplier tubes (PMT). A fully digital implementation of the Silicon Photomultiplier (dSiPM) has been developed in order to overcome the deficiencies and limitations of the so far only analog SiPMs (aSiPMs). Our sensor is based on arrays of single photon avalanche photodiodes (SPADs) integrated in a standard CMOS process. Photons are detected directly by sensing the voltage at the SPAD anode using a dedicated cell electronics block next to each diode. This block also contains active quenching and recharge circuits as well as a one bit memory for the selective inhibit of detector cells. A balanced trigger network is used to propagate the trigger signal from all cells to the integrated time-to-digital converter. In consequence, photons are detected and counted as digital signals, thus making the sensor less susceptible to temperature variations and electronic noise. The integration with CMOS logic provides the added benefit of low power consumption and possible integration of data post-processing directly in the sensor. In this overview paper, we discuss the sensor architecture together with its characteristics with a focus on scalability and practicability aspects for applications in medical imaging, high energy- and astrophysics.

a Low-Power Wireless Sensor Network for Monitoring the Microcrack Initiations in Aerospace Composites

NASA Astrophysics Data System (ADS)

Li, Jian; Plotnikov, Yuri; Lin, Wendy W.

2008-02-01

A low power wireless sensor network was developed to monitor the microcrack events in aerospace composites. The microcracks in the composites mostly result from a stress loading or temperature and/or humidity cycles. Generally, a single microcrack is too small to be detected by conventional techniques such as X-ray or ultrasonic C-scan. The whole developed sensor network is aimed to capture the released acoustic signals by the microcracking events in real time. It comprises of a receiving station as well as a series of sensor nodes. Each sensor node includes two acoustic emission transducers as well as two signal amplification and data acquisition channels. Much of our development effort has been focused on reducing the power consumption of each node and improving the detection reliability for each event. Each sensor node is battery-powered and works in a sleep mode most of time. Once a microcrack is initiated in the composite, the acoustic signal triggers the node and wakes it up. The node will then react in several microseconds and digitize the signal. The digitized data is sent to the station wirelessly. The developed wireless sensor network system has been validated with microscopy of microcracked samples after temperature and humidity cycling and has proved to be an effective tool for microcracking detection. Furthermore, our low power consumption design and sophisticated wireless transmission mechanism enables a system with great potential for field structural health monitoring applications.

A CMOS smart temperature and humidity sensor with combined readout.

PubMed

Eder, Clemens; Valente, Virgilio; Donaldson, Nick; Demosthenous, Andreas

2014-09-16

A fully-integrated complementary metal-oxide semiconductor (CMOS) sensor for combined temperature and humidity measurements is presented. The main purpose of the device is to monitor the hermeticity of micro-packages for implanted integrated circuits and to ensure their safe operation by monitoring the operating temperature and humidity on-chip. The smart sensor has two modes of operation, in which either the temperature or humidity is converted into a digital code representing a frequency ratio between two oscillators. This ratio is determined by the ratios of the timing capacitances and bias currents in both oscillators. The reference oscillator is biased by a current whose temperature dependency is complementary to the proportional to absolute temperature (PTAT) current. For the temperature measurement, this results in an exceptional normalized sensitivity of about 0.77%/°C at the accepted expense of reduced linearity. The humidity sensor is a capacitor, whose value varies linearly with relative humidity (RH) with a normalized sensitivity of 0.055%/% RH. For comparison, two versions of the humidity sensor with an area of either 0.2 mm2 or 1.2 mm2 were fabricated in a commercial 0.18 μm CMOS process. The on-chip readout electronics operate from a 5 V power supply and consume a current of approximately 85 µA.

Digital Sensor Technology

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

Ted Quinn; Jerry Mauck; Richard Bockhorst

The nuclear industry has been slow to incorporate digital sensor technology into nuclear plant designs due to concerns with digital qualification issues. However, the benefits of digital sensor technology for nuclear plant instrumentation are substantial in terms of accuracy, reliability, availability, and maintainability. This report demonstrates these benefits in direct comparisons of digital and analog sensor applications. It also addresses the qualification issues that must be addressed in the application of digital sensor technology.

On Certain New Methodology for Reducing Sensor and Readout Electronics Circuitry Noise in Digital Domain

NASA Technical Reports Server (NTRS)

Kizhner, Semion; Miko, Joseph; Bradley, Damon; Heinzen, Katherine

2008-01-01

NASA Hubble Space Telescope (HST) and upcoming cosmology science missions carry instruments with multiple focal planes populated with many large sensor detector arrays. These sensors are passively cooled to low temperatures for low-level light (L3) and near-infrared (NIR) signal detection, and the sensor readout electronics circuitry must perform at extremely low noise levels to enable new required science measurements. Because we are at the technological edge of enhanced performance for sensors and readout electronics circuitry, as determined by thermal noise level at given temperature in analog domain, we must find new ways of further compensating for the noise in the signal digital domain. To facilitate this new approach, state-of-the-art sensors are augmented at their array hardware boundaries by non-illuminated reference pixels, which can be used to reduce noise attributed to sensors. There are a few proposed methodologies of processing in the digital domain the information carried by reference pixels, as employed by the Hubble Space Telescope and the James Webb Space Telescope Projects. These methods involve using spatial and temporal statistical parameters derived from boundary reference pixel information to enhance the active (non-reference) pixel signals. To make a step beyond this heritage methodology, we apply the NASA-developed technology known as the Hilbert- Huang Transform Data Processing System (HHT-DPS) for reference pixel information processing and its utilization in reconfigurable hardware on-board a spaceflight instrument or post-processing on the ground. The methodology examines signal processing for a 2-D domain, in which high-variance components of the thermal noise are carried by both active and reference pixels, similar to that in processing of low-voltage differential signals and subtraction of a single analog reference pixel from all active pixels on the sensor. Heritage methods using the aforementioned statistical parameters in the digital domain (such as statistical averaging of the reference pixels themselves) zeroes out the high-variance components, and the counterpart components in the active pixels remain uncorrected. This paper describes how the new methodology was demonstrated through analysis of fast-varying noise components using the Hilbert-Huang Transform Data Processing System tool (HHT-DPS) developed at NASA and the high-level programming language MATLAB (Trademark of MathWorks Inc.), as well as alternative methods for correcting for the high-variance noise component, using an HgCdTe sensor data. The NASA Hubble Space Telescope data post-processing, as well as future deep-space cosmology projects on-board instrument data processing from all the sensor channels, would benefit from this effort.

Ultra-miniature wireless temperature sensor for thermal medicine applications.

PubMed

Khairi, Ahmad; Hung, Shih-Chang; Paramesh, Jeyanandh; Fedder, Gary; Rabin, Yoed

2011-01-01

This study presents a prototype design of an ultra-miniature, wireless, battery-less, and implantable temperature-sensor, with applications to thermal medicine such as cryosurgery, hyperthermia, and thermal ablation. The design aims at a sensory device smaller than 1.5 mm in diameter and 3 mm in length, to enable minimally invasive deployment through a hypodermic needle. While the new device may be used for local temperature monitoring, simultaneous data collection from an array of such sensors can be used to reconstruct the 3D temperature field in the treated area, offering a unique capability in thermal medicine. The new sensory device consists of three major subsystems: a temperature-sensing core, a wireless data-communication unit, and a wireless power reception and management unit. Power is delivered wirelessly to the implant from an external source using an inductive link. To meet size requirements while enhancing reliability and minimizing cost, the implant is fully integrated in a regular foundry CMOS technology (0.15 μm in the current study), including the implant-side inductor of the power link. A temperature-sensing core that consists of a proportional-to-absolute-temperature (PTAT) circuit has been designed and characterized. It employs a microwatt chopper stabilized op-amp and dynamic element-matched current sources to achieve high absolute accuracy. A second order sigma-delta (Σ-Δ) analog-to-digital converter (ADC) is designed to convert the temperature reading to a digital code, which is transmitted by backscatter through the same antenna used for receiving power. A high-efficiency multi-stage differential CMOS rectifier has been designed to provide a DC supply to the sensing and communication subsystems. This paper focuses on the development of the all-CMOS temperature sensing core circuitry part of the device, and briefly reviews the wireless power delivery and communication subsystems.

Wireless remote weather monitoring system based on MEMS technologies.

PubMed

Ma, Rong-Hua; Wang, Yu-Hsiang; Lee, Chia-Yen

2011-01-01

This study proposes a wireless remote weather monitoring system based on Micro-Electro-Mechanical Systems (MEMS) and wireless sensor network (WSN) technologies comprising sensors for the measurement of temperature, humidity, pressure, wind speed and direction, integrated on a single chip. The sensing signals are transmitted between the Octopus II-A sensor nodes using WSN technology, following amplification and analog/digital conversion (ADC). Experimental results show that the resistance of the micro temperature sensor increases linearly with input temperature, with an average TCR (temperature coefficient of resistance) value of 8.2 × 10(-4) (°C(-1)). The resistance of the pressure sensor also increases linearly with air pressure, with an average sensitivity value of 3.5 × 10(-2) (Ω/kPa). The sensitivity to humidity increases with ambient temperature due to the effect of temperature on the dielectric constant, which was determined to be 16.9, 21.4, 27.0, and 38.2 (pF/%RH) at 27 °C, 30 °C, 40 °C, and 50 °C, respectively. The velocity of airflow is obtained by summing the variations in resistor response as airflow passed over the sensors providing sensitivity of 4.2 × 10(-2), 9.2 × 10(-2), 9.7 × 10(-2) (Ω/ms(-1)) with power consumption by the heating resistor of 0.2, 0.3, and 0.5 W, respectively. The passage of air across the surface of the flow sensors prompts variations in temperature among each of the sensing resistors. Evaluating these variations in resistance caused by the temperature change enables the measurement of wind direction.

Flexible digital x-ray technology for far-forward remote diagnostic and conformal x-ray imaging applications

NASA Astrophysics Data System (ADS)

Smith, Joseph; Marrs, Michael; Strnad, Mark; Apte, Raj B.; Bert, Julie; Allee, David; Colaneri, Nicholas; Forsythe, Eric; Morton, David

2013-05-01

Today's flat panel digital x-ray image sensors, which have been in production since the mid-1990s, are produced exclusively on glass substrates. While acceptable for use in a hospital or doctor's office, conventional glass substrate digital x-ray sensors are too fragile for use outside these controlled environments without extensive reinforcement. Reinforcement, however, significantly increases weight, bulk, and cost, making them impractical for far-forward remote diagnostic applications, which demand rugged and lightweight x-ray detectors. Additionally, glass substrate x-ray detectors are inherently rigid. This limits their use in curved or bendable, conformal x-ray imaging applications such as the non-destructive testing (NDT) of oil pipelines. However, by extending low-temperature thin-film transistor (TFT) technology previously demonstrated on plastic substrate- based electrophoretic and organic light emitting diode (OLED) flexible displays, it is now possible to manufacture durable, lightweight, as well as flexible digital x-ray detectors. In this paper, we discuss the principal technical approaches used to apply flexible display technology to two new large-area flexible digital x-ray sensors for defense, security, and industrial applications and demonstrate their imaging capabilities. Our results include a 4.8″ diagonal, 353 x 463 resolution, flexible digital x-ray detector, fabricated on a 6″ polyethylene naphthalate (PEN) plastic substrate; and a larger, 7.9″ diagonal, 720 x 640 resolution, flexible digital x-ray detector also fabricated on PEN and manufactured on a gen 2 (370 x 470 mm) substrate.

Ultra-Compact Motor Controller

NASA Technical Reports Server (NTRS)

Townsend, William T.; Crowell, Adam; Hauptman, Traveler; Pratt, Gill Andrews

2012-01-01

This invention is an electronically commutated brushless motor controller that incorporates Hall-array sensing in a small, 42-gram package that provides 4096 absolute counts per motor revolution position sensing. The unit is the size of a miniature hockey puck, and is a 44-pin male connector that provides many I/O channels, including CANbus, RS-232 communications, general-purpose analog and digital I/O (GPIO), analog and digital Hall inputs, DC power input (18-90 VDC, 0-l0 A), three-phase motor outputs, and a strain gauge amplifier. This controller replaces air cooling with conduction cooling via a high-thermal-conductivity epoxy casting. A secondary advantage of the relatively good heat conductivity that comes with ultra-small size is that temperature differences within the controller become smaller, so that it is easier to measure the hottest temperature in the controller with fewer temperature sensors, or even one temperature sensor. Another size-sensitive design feature is in the approach to electrical noise immunity. At a very small size, where conduction paths are much shorter than in conventional designs, the ground becomes essentially isopotential, and so certain (space-consuming) electrical noise control components become unnecessary, which helps make small size possible. One winding-current sensor, applied to all of the windings in fast sequence, is smaller and wastes less power than the two or more sensors conventionally used to sense and control winding currents. An unexpected benefit of using only one current sensor is that it actually improves the precision of current control by using the "same" sensors to read each of the three phases. Folding the encoder directly into the controller electronics eliminates a great deal of redundant electronics, packaging, connectors, and hook-up wiring. The reduction of wires and connectors subtracts substantial bulk and eliminates their role in behaving as EMI (electro-magnetic interference) antennas. A shared knowledge by each motor controller of the state of all the motors in the system at 500 Hz also allows parallel processing of higher-level kinematic matrix calculations.

Using a Computer to Monitor Temperature and Light.

ERIC Educational Resources Information Center

Watson, J. M.

1984-01-01

A 16K Sinclair ZX81 microcomputer equipped with an analog to digital board and a Sinclair printer was used to capture data continuously from a total of eight temperature or light sensors. Describes the construction of the peripherals, explains how to connect them together, and provides a program to run the ZX81. (Author/JN)

Fiber optic and laser sensors X; Proceedings of the Meeting, Boston, MA, Sept. 8-11, 1992

NASA Technical Reports Server (NTRS)

Udd, Eric (Editor); Depaula, Ramon P. (Editor)

1993-01-01

Topics addressed include acoustic and pressure sensors; fiber optic gyros; electric and magnetic field sensors; bend, strain, and temperature sensors; industrial applications of sensors; and processing techniques. Particular attention is given to fiber optic interferometric acoustic sensors for wind tunnel applications, polished coupler and resonator fabrication, second-harmonic detection for rotation sensing in fiber optic gyros, simplified control theory in closed-loop fiber optic gyroscopes, and a Fabry-Perot sensor with digital signal processing for the measurement of magnetostriction. Also discussed are a Bragg fiber laser sensor, commercialization of fiber optic strain gauge systems, thermal ignition in hazardous environments due to stray light from optical fibers, a system for absolute measurements by interferometric sensors, and high-performance interferometric demodulation techniques.

Advanced Wireless Sensor Nodes - MSFC

NASA Technical Reports Server (NTRS)

Varnavas, Kosta; Richeson, Jeff

2017-01-01

NASA field center Marshall Space Flight Center (Huntsville, AL), has invested in advanced wireless sensor technology development. Developments for a wireless microcontroller back-end were primarily focused on the commercial Synapse Wireless family of devices. These devices have many useful features for NASA applications, good characteristics and the ability to be programmed Over-The-Air (OTA). The effort has focused on two widely used sensor types, mechanical strain gauges and thermal sensors. Mechanical strain gauges are used extensively in NASA structural testing and even on vehicle instrumentation systems. Additionally, thermal monitoring with many types of sensors is extensively used. These thermal sensors include thermocouples of all types, resistive temperature devices (RTDs), diodes and other thermal sensor types. The wireless thermal board will accommodate all of these types of sensor inputs to an analog front end. The analog front end on each of the sensors interfaces to the Synapse wireless microcontroller, based on the Atmel Atmega128 device. Once the analog sensor output data is digitized by the onboard analog to digital converter (A/D), the data is available for analysis, computation or transmission. Various hardware features allow custom embedded software to manage battery power to enhance battery life. This technology development fits nicely into using numerous additional sensor front ends, including some of the low-cost printed circuit board capacitive moisture content sensors currently being developed at Auburn University.

Digital Simulation Of Precise Sensor Degradations Including Non-Linearities And Shift Variance

NASA Astrophysics Data System (ADS)

Kornfeld, Gertrude H.

1987-09-01

Realistic atmospheric and Forward Looking Infrared Radiometer (FLIR) degradations were digitally simulated. Inputs to the routine are environmental observables and the FLIR specifications. It was possible to achieve realism in the thermal domain within acceptable computer time and random access memory (RAM) requirements because a shift variant recursive convolution algorithm that well describes thermal properties was invented and because each picture element (pixel) has radiative temperature, a materials parameter and range and altitude information. The computer generation steps start with the image synthesis of an undegraded scene. Atmospheric and sensor degradation follow. The final result is a realistic representation of an image seen on the display of a specific FLIR.

High precision silicon piezo resistive SMART pressure sensor

NASA Astrophysics Data System (ADS)

Brown, Rod

2005-01-01

Instruments for test and calibration require a pressure sensor that is precise and stable. Market forces also dictate a move away from single measurand test equipment and, certainly in the case of pressure, away from single range equipment. A pressure `module' is required which excels in pressure measurement but is interchangble with sensors for other measurands. A communications interface for such a sensor has been specified. Instrument Digital Output Sensor (IDOS) that permits this interchanagability and allows the sensor to be inside or outside the measuring instrument. This paper covers the design and specification of a silicon diaphragm piezo resistive SMART sensor using this interface. A brief history of instrument sensors will be given to establish the background to this development. Design choices of the silicon doping, bridge energisation method, temperature sensing, signal conversion, data processing, compensation method, communications interface will be discussed. The physical format of the `in-instrument' version will be shown and then extended to the packaging design for the external version. Test results will show the accuracy achieved exceeds the target of 0.01%FS over a range of temperatures.

Improved charge injection device and a focal plane interface electronics board for stellar tracking

NASA Technical Reports Server (NTRS)

Michon, G. J.; Burke, H. K.

1984-01-01

An improved Charge Injection Device (CID) stellar tracking sensor and an operating sensor in a control/readout electronics board were developed. The sensor consists of a shift register scanned, 256x256 CID array organized for readout of 4x4 subarrays. The 4x4 subarrays can be positioned anywhere within the 256x256 array with a 2 pixel resolution. This allows continuous tracking of a number of stars simultaneously since nine pixels (3x3) centered on any star can always be read out. Organization and operation of this sensor and the improvements in design and semiconductor processing are described. A hermetic package incorporating an internal thermoelectric cooler assembled using low temperature solders was developed. The electronics board, which contains the sensor drivers, amplifiers, sample hold circuits, multiplexer, analog to digital converter, and the sensor temperature control circuits, is also described. Packaged sensors were evaluated for readout efficiency, spectral quantum efficiency, temporal noise, fixed pattern noise, and dark current. Eight sensors along with two tracker electronics boards were completed, evaluated, and delivered.

IMAPS Device Packaging Conference 2017 - Engineered Micro Systems & Devices Track

NASA Technical Reports Server (NTRS)

Varnavas, Kosta

2017-01-01

NASA field center Marshall Space Flight Center (Huntsville, AL), has invested in advanced wireless sensor technology development. Developments for a wireless microcontroller back-end were primarily focused on the commercial Synapse Wireless family of devices. These devices have many useful features for NASA applications, good characteristics and the ability to be programmed Over-The-Air (OTA). The effort has focused on two widely used sensor types, mechanical strain gauges and thermal sensors. Mechanical strain gauges are used extensively in NASA structural testing and even on vehicle instrumentation systems. Additionally, thermal monitoring with many types of sensors is extensively used. These thermal sensors include thermocouples of all types, resistive temperature devices (RTDs), diodes and other thermal sensor types. The wireless thermal board will accommodate all of these types of sensor inputs to an analog front end. The analog front end on each of the sensors interfaces to the Synapse wireless microcontroller, based on the Atmel Atmega128 device. Once the analog sensor output data is digitized by the onboard analog to digital converter (A/D), the data is available for analysis, computation or transmission. Various hardware features allow custom embedded software to manage battery power to enhance battery life. This technology development fits nicely into using numerous additional sensor front ends, including some of the low-cost printed circuit board capacitive moisture content sensors currently being developed at Auburn University.

Design and evaluation of a flow-to-frequency converter circuit with thermal feedback

NASA Astrophysics Data System (ADS)

Pawlowski, Eligiusz

2017-05-01

A novel thermal flow sensor with a frequency output is presented. The sensor provides a pulse-train output whose frequency is related to the fluid flow rate around a self-heating thermistor. The integrating properties of the temperature sensor have been used, which allowed for realization of the pulse frequency modulator with a thermal feedback loop, stabilizing the temperature of the sensor placed in the flowing medium. The system assures a balance of the amount of heat supplied in the impulses to the sensor and the heat given up by the sensor in a continuous way to the flowing medium. Therefore the frequency of output pulse-train is proportional to the medium flow velocity around the sensor. The special feature of the presented solution is the total integration of the thermal sensor with the measurement signal conditioning system. i.e. the sensor and conditioning system are not separate elements of the measurement circuit, but constitute a whole in the form of a thermal heat-balance mode flow-to-frequency converter. The frequency signal from the converter may be directly connected to the microprocessor digital input, which with use of the standard built-in counters may convert the frequency into a numerical value of high precision. The sensor has been experimentally characterized as a function of the average flow velocity of air at room temperature.

Design and Experimental Verification of a 0.19 V 53 μW 65 nm CMOS Integrated Supply-Sensing Sensor With a Supply-Insensitive Temperature Sensor and an Inductive-Coupling Transmitter for a Self-Powered Bio-sensing System Using a Biofuel Cell.

PubMed

Kobayashi, Atsuki; Ikeda, Kei; Ogawa, Yudai; Kai, Hiroyuki; Nishizawa, Matsuhiko; Nakazato, Kazuo; Niitsu, Kiichi

2017-12-01

In this paper, we present a self-powered bio-sensing system with the capability of proximity inductive-coupling communication for supply sensing and temperature monitoring. The proposed bio-sensing system includes a biofuel cell as a power source and a sensing frontend that is associated with the CMOS integrated supply-sensing sensor. The sensor consists of a digital-based gate leakage timer, a supply-insensitive time-domain temperature sensor, and a current-driven inductive-coupling transmitter and achieves low-voltage operation. The timer converts the output voltage from a biofuel cell to frequency. The temperature sensor provides a pulse width modulation (PWM) output that is not dependent on the supply voltage, and the associated inductive-coupling transmitter enables proximity communication. A test chip was fabricated in 65 nm CMOS technology and consumed 53 μW with a supply voltage of 190 mV. The low-voltage-friendly design satisfied the performance targets of each integrated sensor without any trimming. The chips allowed us to successfully demonstrate proximity communication with an asynchronous receiver, and the measurement results show the potential for self-powered operation using biofuel cells. The analysis and experimental verification of the system confirmed their robustness.

Summary of current radiometric calibration coefficients for Landsat MSS, TM, ETM+, and EO-1 ALI sensors

USGS Publications Warehouse

Chander, G.; Markham, B.L.; Helder, D.L.

2009-01-01

This paper provides a summary of the current equations and rescaling factors for converting calibrated Digital Numbers (DNs) to absolute units of at-sensor spectral radiance, Top-Of-Atmosphere (TOA) reflectance, and at-sensor brightness temperature. It tabulates the necessary constants for the Multispectral Scanner (MSS), Thematic Mapper (TM), Enhanced Thematic Mapper Plus (ETM+), and Advanced Land Imager (ALI) sensors. These conversions provide a basis for standardized comparison of data in a single scene or between images acquired on different dates or by different sensors. This paper forms a needed guide for Landsat data users who now have access to the entire Landsat archive at no cost.

Summary of Current Radiometric Calibration Coefficients for Landsat MSS, TM, ETM+, and EO-1 ALI Sensors

NASA Technical Reports Server (NTRS)

Chander, Gyanesh; Markham, Brian L.; Helder, Dennis L.

2009-01-01

This paper provides a summary of the current equations and rescaling factors for converting calibrated Digital Numbers (DNs) to absolute units of at-sensor spectral radiance, Top-Of- Atmosphere (TOA) reflectance, and at-sensor brightness temperature. It tabulates the necessary constants for the Multispectral Scanner (MSS), Thematic Mapper (TM), Enhanced Thematic Mapper Plus (ETM+), and Advanced Land Imager (ALI) sensors. These conversions provide a basis for standardized comparison of data in a single scene or between images acquired on different dates or by different sensors. This paper forms a needed guide for Landsat data users who now have access to the entire Landsat archive at no cost.

Wearable vital parameters monitoring system

NASA Astrophysics Data System (ADS)

Caramaliu, Radu Vadim; Vasile, Alexandru; Bacis, Irina

2015-02-01

The system we propose monitors body temperature, heart rate and beside this, it tracks if the person who wears it suffers a faint. It uses a digital temperature sensor, a pulse sensor and a gravitational acceleration sensor to monitor the eventual faint or small heights free falls. The system continuously tracks the GPS position when available and stores the last valid data. So, when measuring abnormal vital parameters the module will send an SMS, using the GSM cellular network , with the person's social security number, the last valid GPS position for that person, the heart rate, the body temperature and, where applicable, a valid fall alert or non-valid fall alert. Even though such systems exist, they contain only faint detection or heart rate detection. Usually there is a strong correlation between low/high heart rate and an eventual faint. Combining both features into one system results in a more reliable detection device.

Data acquisition in a high-speed rotating frame for New Mexico Institute of Mining and Technology liquid sodium αω dynamo experiment.

PubMed

Si, Jiahe; Colgate, Stirling A; Li, Hui; Martinic, Joe; Westpfahl, David

2013-10-01

New Mexico Institute of Mining and Technology liquid sodium αω-dynamo experiment models the magnetic field generation in the universe as discussed in detail by Colgate, Li, and Pariev [Phys. Plasmas 8, 2425 (2001)]. To obtain a quasi-laminar flow with magnetic Reynolds number R(m) ~ 120, the dynamo experiment consists of two co-axial cylinders of 30.5 cm and 61 cm in diameter spinning up to 70 Hz and 17.5 Hz, respectively. During the experiment, the temperature of the cylinders must be maintained to 110 °C to ensure that the sodium remains fluid. This presents a challenge to implement a data acquisition (DAQ) system in such high temperature, high-speed rotating frame, in which the sensors (including 18 Hall sensors, 5 pressure sensors, and 5 temperature sensors, etc.) are under the centrifugal acceleration up to 376g. In addition, the data must be transmitted and stored in a computer 100 ft away for safety. The analog signals are digitized, converted to serial signals by an analog-to-digital converter and a field-programmable gate array. Power is provided through brush/ring sets. The serial signals are sent through ring/shoe sets capacitively, then reshaped with cross-talk noises removed. A microcontroller-based interface circuit is used to decode the serial signals and communicate with the data acquisition computer. The DAQ accommodates pressure up to 1000 psi, temperature up to more than 130 °C, and magnetic field up to 1000 G. First physics results have been analyzed and published. The next stage of the αω-dynamo experiment includes the DAQ system upgrade.

Effects of measurement resolution on the analysis of temperature time series for stream-aquifer flux estimation

NASA Astrophysics Data System (ADS)

Soto-López, Carlos D.; Meixner, Thomas; Ferré, Ty P. A.

2011-12-01

From its inception in the mid-1960s, the use of temperature time series (thermographs) to estimate vertical fluxes has found increasing use in the hydrologic community. Beginning in 2000, researchers have examined the impacts of measurement and parameter uncertainty on the estimates of vertical fluxes. To date, the effects of temperature measurement discretization (resolution), a characteristic of all digital temperature loggers, on the determination of vertical fluxes has not been considered. In this technical note we expand the analysis of recently published work to include the effects of temperature measurement resolution on estimates of vertical fluxes using temperature amplitude and phase shift information. We show that errors in thermal front velocity estimation introduced by discretizing thermographs differ when amplitude or phase shift data are used to estimate vertical fluxes. We also show that under similar circumstances sensor resolution limits the range over which vertical velocities are accurately reproduced more than uncertainty in temperature measurements, uncertainty in sensor separation distance, and uncertainty in the thermal diffusivity combined. These effects represent the baseline error present and thus the best-case scenario when discrete temperature measurements are used to infer vertical fluxes. The errors associated with measurement resolution can be minimized by using the highest-resolution sensors available. But thoughtful experimental design could allow users to select the most cost-effective temperature sensors to fit their measurement needs.

Flight testing of a fiber optic temperature sensor

NASA Technical Reports Server (NTRS)

Finney, M. J.; Tregay, G. W.; Calabrese, P. R.

1993-01-01

A fiber optic temperature sensor (FOTS) system consisting of an optical probe, a flexible fiber optic cable, and an electro-optic signal processor was fabricated to measure the gas temperature in a turbine engine. The optical probe contained an emissive source embedded in a sapphire lightguide coupled to a fiber-optic jumper cable and was retrofitted into an existing thermocouple probe housing. The flexible fiber optic cable was constructed with 200 micron core, polyimide-coated fiber and was ruggedized for an aircraft environment. The electro-optic signal processing unit was used to ratio the intensities of two wavelength intervals and provided an analog output value of the indicated temperature. Subsequently, this optical sensor system was installed on a NASA Dryden F-15 Highly Integrated Digital Electronic Control (HIDEC) Aircraft Engine and several flight tests were conducted. Over the course of flight testing, the FOTS system's response was proportional to the average of the existing thermocouples sensing the changes in turbine engine thermal conditions.

Integrating Metal-Oxide-Decorated CNT Networks with a CMOS Readout in a Gas Sensor

PubMed Central

Lee, Hyunjoong; Lee, Sanghoon; Kim, Dai-Hong; Perello, David; Park, Young June; Hong, Seong-Hyeon; Yun, Minhee; Kim, Suhwan

2012-01-01

We have implemented a tin-oxide-decorated carbon nanotube (CNT) network gas sensor system on a single die. We have also demonstrated the deposition of metallic tin on the CNT network, its subsequent oxidation in air, and the improvement of the lifetime of the sensors. The fabricated array of CNT sensors contains 128 sensor cells for added redundancy and increased accuracy. The read-out integrated circuit (ROIC) was combined with coarse and fine time-to-digital converters to extend its resolution in a power-efficient way. The ROIC is fabricated using a 0.35 μm CMOS process, and the whole sensor system consumes 30 mA at 5 V. The sensor system was successfully tested in the detection of ammonia gas at elevated temperatures. PMID:22736966

Research on application of photoelectric rotary encoder in space optical remote sensor

NASA Astrophysics Data System (ADS)

Zheng, Jun; Qi, Shao-fan; Wang, Yuan-yuan; Zhang, Zhan-dong

2016-11-01

For space optical remote sensor, especially wide swath detecting sensor, the focusing control system for the focal plane should be well designed to obtain the best image quality. The crucial part of this system is the measuring instrument. For previous implements, the potentiometer, which is essentially a voltage divider, is usually introduced to conduct the position in feedback closed-loop control process system. However, the performances of both electro-mechanical and digital potentiometers is limited in accuracy, temperature coefficients, and scale range. To have a better performance of focal plane moving detection, this article presents a new measuring implement with photoelectric rotary encoder, which consists of the photoelectric conversion system and the signal process system. In this novel focusing control system, the photoelectric conversion system is fixed on main axis, which can transform the angle information into a certain analog signal. Through the signal process system, after analog-to-digital converting and data format processing of the certain analog signal, the focusing control system can receive the digital precision angle position which can be used to deduct the current moving position of the focal plane. For utilization of space optical remote sensor in aerospace areas, the reliability design of photoelectric rotary encoder system should be considered with highest priority. As mentioned above, this photoelectric digital precision angle measurement device is well designed for this real-time control and dynamic measurement system, because its characters of high resolution, high accuracy, long endurance, and easy to maintain.

Flexible phosphor sensors: a digital supplement or option to rigid sensors.

PubMed

Glazer, Howard S

2014-01-01

An increasing number of dental practices are upgrading from film radiography to digital radiography, for reasons that include faster image processing, easier image access, better patient education, enhanced data storage, and improved office productivity. Most practices that have converted to digital technology use rigid, or direct, sensors. Another digital option is flexible phosphor sensors, also called indirect sensors or phosphor storage plates (PSPs). Flexible phosphor sensors can be advantageous for use with certain patients who may be averse to direct sensors, and they can deliver a larger image area. Additionally, sensor cost for replacement PSPs is considerably lower than for hard sensors. As such, flexible phosphor sensors appear to be a viable supplement or option to direct sensors.

Climatic summaries and documentation for the primary meteorological station, H.J. Andrews Experimental Forest, 1972 To 1984.

Treesearch

Frederick A. Bierlmaler; Arthur McKee

1989-01-01

This report describes the primary meteorological station at the H.J. Andrews Experimental Forest (elev. 426 m, lat. 44°15' N., long. 122°10' W.) in the Willamette National Forest, the automatic digital data logger, sensors, and data-processing procedures used in measuring air temperature, dewpoint temperature, windspeed, precipitation, and solar radiation....

Micro-machined resonator oscillator

DOEpatents

Koehler, Dale R.; Sniegowski, Jeffry J.; Bivens, Hugh M.; Wessendorf, Kurt O.

1994-01-01

A micro-miniature resonator-oscillator is disclosed. Due to the miniaturization of the resonator-oscillator, oscillation frequencies of one MHz and higher are utilized. A thickness-mode quartz resonator housed in a micro-machined silicon package and operated as a "telemetered sensor beacon" that is, a digital, self-powered, remote, parameter measuring-transmitter in the FM-band. The resonator design uses trapped energy principles and temperature dependence methodology through crystal orientation control, with operation in the 20-100 MHz range. High volume batch-processing manufacturing is utilized, with package and resonator assembly at the wafer level. Unique design features include squeeze-film damping for robust vibration and shock performance, capacitive coupling through micro-machined diaphragms allowing resonator excitation at the package exterior, circuit integration and extremely small (0.1 in. square) dimensioning. A family of micro-miniature sensor beacons is also disclosed with widespread applications as bio-medical sensors, vehicle status monitors and high-volume animal identification and health sensors. The sensor family allows measurement of temperatures, chemicals, acceleration and pressure. A microphone and clock realization is also available.

Development of TGS2611 methane sensor and SHT11 humidity and temperature sensor for measuring greenhouse gas on peatlands in south kalimantan, indonesia

NASA Astrophysics Data System (ADS)

Sugriwan, I.; Soesanto, O.

2017-05-01

The research was focused on development of data acquisition system to monitor the content of methane, relative humidity and temperature on peatlands in South Kalimantan, Indonesia. Methane is one of greenhouse gases that emitted from peatlands; while humidity and temperature are important parameters of microclimate on peatlands. The content of methane, humidity and temperature are three parameters were monitored digitally, real time, continuously and automatically record by data acquisition systems that interfaced to the personal computer. The hardware of data acquisition system consists of power supply unit, TGS2611 methane gas sensor, SHT11 humidity and temperature sensors, voltage follower, ATMega8535 microcontroller, 16 × 2 LCD character and personal computer. ATMega8535 module is a device to manage all part in measuring instrument. The software which is responsible to take sensor data, calculate characteristic equation and send data to 16 × 2 LCD character are Basic Compiler. To interface between measuring instrument and personal computer is maintained by Delphi 7. The result of data acquisition showed on 16 × 2 LCD characters, PC monitor and database with developed by XAMPP. Methane, humidity, and temperature which release from peatlands are trapped by Closed-Chamber Measurement with dimension 60 × 50 × 40 cm3. TGS2611 methane gas sensor and SHT11 humidity and temperature sensor are calibrated to determine transfer function used to data communication between sensors and microcontroller and integrated into ATMega8535 Microcontroller. Calculation of RS and RL of TGS2611 methane gas sensor refer to data sheet and obtained respectively 1360 ohm and 905 ohm. The characteristic equation of TGS2611 satisfies equation VRL = 0.561 ln n - 2.2641 volt, with n is a various concentrations and VRL in volt. The microcontroller maintained the voltage signal than interfaced it to liquid crystal displays and personal computer (laptop) to display result of the measurement. The result of data acquisition saved on excels and database format.

A Differential Resonant Accelerometer with Low Cross-Interference and Temperature Drift

PubMed Central

Li, Bo; Zhao, Yulong; Li, Cun; Cheng, Rongjun; Sun, Dengqiang; Wang, Songli

2017-01-01

Presented in this paper is a high-performance resonant accelerometer with low cross-interference, low temperature drift and digital output. The sensor consists of two quartz double-ended tuning forks (DETFs) and a silicon substrate. A new differential silicon substrate is proposed to reduce the temperature drift and cross-interference from the undesirable direction significantly. The natural frequency of the quartz DETF is theoretically calculated, and then the axial stress on the vibration beams is verified through finite element method (FEM) under a 100 g acceleration which is loaded on x-axis, y-axis and z-axis, respectively. Moreover, sensor chip is wire-bonded to a printed circuit board (PCB) which contains two identical oscillating circuits. In addition, a steel shell is selected to package the sensor for experiments. Benefiting from the distinctive configuration of the differential structure, the accelerometer characteristics such as temperature drift and cross-interface are improved. The experimental results demonstrate that the cross-interference is lower than 0.03% and the temperature drift is about 18.16 ppm/°C. PMID:28106798

An on-line monitoring system for oil-film, pressure and temperature distributions in large-scale hydro-generator bearings

NASA Astrophysics Data System (ADS)

Höbel, M.; Haffner, K.

1999-05-01

Instrumentation that allows the behaviour of a hydro-generator thrust bearing to be monitored during operation is described. The measurement system was developed at the Asea Brown Boveri corporate research centre in Switzerland and was tested under realistic operating conditions at the Harbin Electric Machinery Company bearing-testing facility in the People's Republic of China. Newly developed fibre-optical proximity probes were used for the on-line monitoring of the thin oil film between the static and rotating parts of the bearing. These sensors are based on a back-reflection technique and can be used for various target materials such as Babbitt and Teflon. The monitoring system comprises about 120 temperature sensors, four pressure sensors and five optical oil-film thickness sensors. Temperature sensors are installed at specific static locations, whereas pressure and oil-film sensors are positioned in the runner and generate data during rotation. A special feature of the monitoring equipment is its on-line processing capability. Digital signal processors operating in parallel handle pressure and oil-film thickness data. Important measurement parameters such as the maximum pressure, maximum temperature and minimum oil-film thickness are displayed on-line. Detailed three-dimensional temperature information on one of the load segments can be obtained from subsequent off-line data analysis. The system also calculates two-dimensional plots of the oil-film thickness and pressure for most of the 12 load segments.

A Soft Sensor for Bioprocess Control Based on Sequential Filtering of Metabolic Heat Signals

PubMed Central

Paulsson, Dan; Gustavsson, Robert; Mandenius, Carl-Fredrik

2014-01-01

Soft sensors are the combination of robust on-line sensor signals with mathematical models for deriving additional process information. Here, we apply this principle to a microbial recombinant protein production process in a bioreactor by exploiting bio-calorimetric methodology. Temperature sensor signals from the cooling system of the bioreactor were used for estimating the metabolic heat of the microbial culture and from that the specific growth rate and active biomass concentration were derived. By applying sequential digital signal filtering, the soft sensor was made more robust for industrial practice with cultures generating low metabolic heat in environments with high noise level. The estimated specific growth rate signal obtained from the three stage sequential filter allowed controlled feeding of substrate during the fed-batch phase of the production process. The biomass and growth rate estimates from the soft sensor were also compared with an alternative sensor probe and a capacitance on-line sensor, for the same variables. The comparison showed similar or better sensitivity and lower variability for the metabolic heat soft sensor suggesting that using permanent temperature sensors of a bioreactor is a realistic and inexpensive alternative for monitoring and control. However, both alternatives are easy to implement in a soft sensor, alone or in parallel. PMID:25264951

A soft sensor for bioprocess control based on sequential filtering of metabolic heat signals.

PubMed

Paulsson, Dan; Gustavsson, Robert; Mandenius, Carl-Fredrik

2014-09-26

Soft sensors are the combination of robust on-line sensor signals with mathematical models for deriving additional process information. Here, we apply this principle to a microbial recombinant protein production process in a bioreactor by exploiting bio-calorimetric methodology. Temperature sensor signals from the cooling system of the bioreactor were used for estimating the metabolic heat of the microbial culture and from that the specific growth rate and active biomass concentration were derived. By applying sequential digital signal filtering, the soft sensor was made more robust for industrial practice with cultures generating low metabolic heat in environments with high noise level. The estimated specific growth rate signal obtained from the three stage sequential filter allowed controlled feeding of substrate during the fed-batch phase of the production process. The biomass and growth rate estimates from the soft sensor were also compared with an alternative sensor probe and a capacitance on-line sensor, for the same variables. The comparison showed similar or better sensitivity and lower variability for the metabolic heat soft sensor suggesting that using permanent temperature sensors of a bioreactor is a realistic and inexpensive alternative for monitoring and control. However, both alternatives are easy to implement in a soft sensor, alone or in parallel.

Ultra-miniature wireless temperature sensor for thermal medicine applications

PubMed Central

Khairi, Ahmad; Hung, Shih-Chang; Paramesh, Jeyanandh; Fedder, Gary; Rabin, Yoed

2017-01-01

This study presents a prototype design of an ultra-miniature, wireless, battery-less, and implantable temperature-sensor, with applications to thermal medicine such as cryosurgery, hyperthermia, and thermal ablation. The design aims at a sensory device smaller than 1.5 mm in diameter and 3 mm in length, to enable minimally invasive deployment through a hypodermic needle. While the new device may be used for local temperature monitoring, simultaneous data collection from an array of such sensors can be used to reconstruct the 3D temperature field in the treated area, offering a unique capability in thermal medicine. The new sensory device consists of three major subsystems: a temperature-sensing core, a wireless data-communication unit, and a wireless power reception and management unit. Power is delivered wirelessly to the implant from an external source using an inductive link. To meet size requirements while enhancing reliability and minimizing cost, the implant is fully integrated in a regular foundry CMOS technology (0.15 μm in the current study), including the implant-side inductor of the power link. A temperature-sensing core that consists of a proportional-to-absolute-temperature (PTAT) circuit has been designed and characterized. It employs a microwatt chopper stabilized op-amp and dynamic element-matched current sources to achieve high absolute accuracy. A second order sigma-delta (Σ-Δ) analog-to-digital converter (ADC) is designed to convert the temperature reading to a digital code, which is transmitted by backscatter through the same antenna used for receiving power. A high-efficiency multi-stage differential CMOS rectifier has been designed to provide a DC supply to the sensing and communication subsystems. This paper focuses on the development of the all-CMOS temperature sensing core circuitry part of the device, and briefly reviews the wireless power delivery and communication subsystems. PMID:28989222

Sensium: an ultra-low-power wireless body sensor network platform: design & application challenges.

PubMed

Wong, A W; McDonagh, D; Omeni, O; Nunn, C; Hernandez-Silveira, M; Burdett, A J

2009-01-01

In this paper we present a system-on-chip for wireless body sensor networks, which integrates a transceiver, hardware MAC protocol, microprocessor, IO peripherals, memories, ADC and custom sensor interfaces. Addressing the challenges in the design, this paper will continue to discuss the issues in the applications of this technology to body worn monitoring for real-time measurement of ECG, heart rate, physical activity, respiration and/or skin temperature. Two application challenges are described; the real-time measurement of energy expenditure using the LifePebble, and; the development issues surrounding the 'Digital Patch'.

Design and Characterization of a Built-In CMOS TID Smart Sensor

NASA Astrophysics Data System (ADS)

Agustin, Javier; Gil, Carlos; Lopez-Vallejo, Marisa; Ituero, Pablo

2015-04-01

This paper describes a total ionization dose (TID) sensor that presents the following advantages: it is a digital sensor able to be integrated in CMOS circuits; it has a configurable sensitivity that allows radiation doses ranging from very low to high levels; its interface helps to integrate this design in a multidisciplinary sensor network; and it is self-timed, hence it does not need a clock signal. We designed, implemented and manufactured the sensor in a 0.35 μm CMOS commercial technology. It was irradiated with a 60Co source. This test was used to characterize the sensor in terms of the radiation response up to 575 krad. After irradiation, we monitored the sensor to control charge redistribution and annealing effects for 80 hours. We also exposed our design to meticulous temperature analysis from 0 to 50°C and we studied the acceleration on the annealing phenomena due to high temperatures. Sensor calibration takes into account the results of all tests. Finally we propose to use this sensor in a self-recovery system. The sensor manufactured in this work has an area of 0.047 mm 2, of which 22% is dedicated to measuring radiation. Its energy per conversion is 463 pJ.

Thermal Characterization of Dynamic Silicon Cantilever Array Sensors by Digital Holographic Microscopy

PubMed Central

Zakerin, Marjan; Novak, Antonin; Toda, Masaya; Emery, Yves; Natalio, Filipe; Butt, Hans-Jürgen; Berger, Rüdiger

2017-01-01

In this paper, we apply a digital holographic microscope (DHM) in conjunction with stroboscopic acquisition synchronization. Here, the temperature-dependent decrease of the first resonance frequency (S1(T)) and Young’s elastic modulus (E1(T)) of silicon micromechanical cantilever sensors (MCSs) are measured. To perform these measurements, the MCSs are uniformly heated from T0 = 298 K to T = 450 K while being externally actuated with a piezo-actuator in a certain frequency range close to their first resonance frequencies. At each temperature, the DHM records the time-sequence of the 3D topographies for the given frequency range. Such holographic data allow for the extracting of the out-of-plane vibrations at any relevant area of the MCSs. Next, the Bode and Nyquist diagrams are used to determine the resonant frequencies with a precision of 0.1 Hz. Our results show that the decrease of resonance frequency is a direct consequence of the reduction of the silicon elastic modulus upon heating. The measured temperature dependence of the Young’s modulus is in very good accordance with the previously-reported values, validating the reliability and applicability of this method for micromechanical sensing applications. PMID:28545236

Design of extensible meteorological data acquisition system based on FPGA

NASA Astrophysics Data System (ADS)

Zhang, Wen; Liu, Yin-hua; Zhang, Hui-jun; Li, Xiao-hui

2015-02-01

In order to compensate the tropospheric refraction error generated in the process of satellite navigation and positioning. Temperature, humidity and air pressure had to be used in concerned models to calculate the value of this error. While FPGA XC6SLX16 was used as the core processor, the integrated silicon pressure sensor MPX4115A and digital temperature-humidity sensor SHT75 are used as the basic meteorological parameter detection devices. The core processer was used to control the real-time sampling of ADC AD7608 and to acquire the serial output data of SHT75. The data was stored in the BRAM of XC6SLX16 and used to generate standard meteorological parameters in NEMA format. The whole design was based on Altium hardware platform and ISE software platform. The system was described in the VHDL language and schematic diagram to realize the correct detection of temperature, humidity, air pressure. The 8-channel synchronous sampling characteristics of AD7608 and programmable external resources of FPGA laid the foundation for the increasing of analog or digital meteorological element signal. The designed meteorological data acquisition system featured low cost, high performance, multiple expansions.

A MGy radiation-hardened sensor instrumentation link for nuclear reactor monitoring and remote handling

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

Verbeeck, Jens; Cao, Ying; Van Uffelen, Marco

Decommissioning, dismantling and remote handling applications in nuclear facilities all require robotic solutions that are able to survive in radiation environments. Recently raised safety, radiation hardness and cost efficiency demands from both the nuclear regulatory and the society impose severe challenges in traditional methods. For example, in case of the dismantling of the Fukushima sites, solutions that survive accumulated doses higher than 1 MGy are mandatory. To allow remote operation of these tools in nuclear environments, electronics were used to be shielded with several centimeters of lead or even completely banned in these solutions. However, shielding electronics always leads tomore » bulky and heavy solutions, which reduces the flexibility of robotic tools. It also requires longer repair time and produces extra waste further in a dismantling or decommissioning cycle. In addition, often in current reactor designs, due to size restrictions and the need to inspect very tight areas there are limitations to the use of shielding. A MGy radiation-hardened sensor instrumentation link developed by MAGyICS provides a solution to build a flexible, easy removable and small I and C module with MGy radiation tolerance without any shielding. Hereby it removes all these pains to implement electronics in robotic tools. The demonstrated solution in this poster is developed for ITER Remote Handling equipments operating in high radiation environments (>1 MGy) in and around the Tokamak. In order to obtain adequately accurate instrumentation and control information, as well as to ease the umbilical management, there is a need of front-end electronics that will have to be located close to those actuators and sensors on the remote handling tool. In particular, for diverter remote handling, it is estimated that these components will face gamma radiation up to 300 Gy/h (in-vessel) and a total dose of 1 MGy. The radiation-hardened sensor instrumentation link presented here, consists of multiple in-house developed, state-of-the-art building blocks. They have all been assessed and characterized up to a dose higher than 1 MGy. The first block in the signal chain is a smaller than 1 uV offset, low noise instrumentation amplifier that has a programmable gain between 8 and 256. This amplifier is followed by a high precision 16 bit ADC. Its main function is to digitize the amplified signal coming from the amplifier. The output of the ADC is a serial digital data stream. The next block is a 8 channel digital multiplexer. It converts the 8 digital data streams into 1 digital data stream. Hereby the instrumentation solution reduces the number of cables from 16 to 1 (8* 2 analogue differential signals). In addition, the multiplexer modules can be combined with other modules to reduce even further the number of cables. Every instrumentation solution requires a stable high precision voltage reference. Therefore also a bandgap reference has been developed and assessed under gamma irradiation. A low jitter, 10 MHz clock generator has been developed and qualified to clock the ADC and the multiplexer with high accuracy. Finally, an on-chip radiation-hard temperature sensor is also included. A complete remote, real-time test setup was prepared by MAGyICS in cooperation with Fusion for Energy to qualify the sensor instrumentation link at SCK-CEN. It is qualified by closely following the ESCC22900 space standard for electronics used in a radiation environment. The main benefit of the sensor instrumentation solution discussed here is that it can be directly employed in a MGy-level accumulated dose radiation environment, therefore it can digitize and multiplex sensor readout values early in the signal chain. Hereby the sensor values are not distorted by external interferences on the long transmission cable. Moreover it allows readout and digitize multiple low-bandwidth sensors ( pressure and temperature sensors, thermocouples, angular resolvers and LVDTs). Hence these instrumentation modules can be used to follow the trend of the digitalization in the nuclear industry. (authors)« less

Maximum Temperature Detection System for Integrated Circuits

NASA Astrophysics Data System (ADS)

Frankiewicz, Maciej; Kos, Andrzej

2015-03-01

The paper describes structure and measurement results of the system detecting present maximum temperature on the surface of an integrated circuit. The system consists of the set of proportional to absolute temperature sensors, temperature processing path and a digital part designed in VHDL. Analogue parts of the circuit where designed with full-custom technique. The system is a part of temperature-controlled oscillator circuit - a power management system based on dynamic frequency scaling method. The oscillator cooperates with microprocessor dedicated for thermal experiments. The whole system is implemented in UMC CMOS 0.18 μm (1.8 V) technology.

Noncontact Measurement Of Shaft Speed, Torque, And Power

NASA Technical Reports Server (NTRS)

Madzsar, George C.

1993-01-01

Noncontact fiber-optic sensor and associated electronic equipment measure twist and speed of rotation of shaft. Measurements determine torque and power. Response of sensor remains linear even at cryogenic temperatures. Reflective strips on rotating shaft reflect two series of light pulses back into optical system. Bidirectional coupler in each of two optical fiber paths separates reflected light from incident light, sending it to photodiode for output to analog-to-digital converter and computer. Sensor requires no slip rings or telemetry to transfer signals from shaft. Well suited for providing data on performances of turbopumps for such cryogenic fluids as liquid oxygen and liquid hydrogen.

Computation of dark frames in digital imagers

NASA Astrophysics Data System (ADS)

Widenhorn, Ralf; Rest, Armin; Blouke, Morley M.; Berry, Richard L.; Bodegom, Erik

2007-02-01

Dark current is caused by electrons that are thermally exited into the conduction band. These electrons are collected by the well of the CCD and add a false signal to the chip. We will present an algorithm that automatically corrects for dark current. It uses a calibration protocol to characterize the image sensor for different temperatures. For a given exposure time, the dark current of every pixel is characteristic of a specific temperature. The dark current of every pixel can therefore be used as an indicator of the temperature. Hot pixels have the highest signal-to-noise ratio and are the best temperature sensors. We use the dark current of a several hundred hot pixels to sense the chip temperature and predict the dark current of all pixels on the chip. Dark current computation is not a new concept, but our approach is unique. Some advantages of our method include applicability for poorly temperature-controlled camera systems and the possibility of ex post facto dark current correction.

Micro-machined resonator oscillator

DOEpatents

Koehler, D.R.; Sniegowski, J.J.; Bivens, H.M.; Wessendorf, K.O.

1994-08-16

A micro-miniature resonator-oscillator is disclosed. Due to the miniaturization of the resonator-oscillator, oscillation frequencies of one MHz and higher are utilized. A thickness-mode quartz resonator housed in a micro-machined silicon package and operated as a telemetered sensor beacon'' that is, a digital, self-powered, remote, parameter measuring-transmitter in the FM-band. The resonator design uses trapped energy principles and temperature dependence methodology through crystal orientation control, with operation in the 20--100 MHz range. High volume batch-processing manufacturing is utilized, with package and resonator assembly at the wafer level. Unique design features include squeeze-film damping for robust vibration and shock performance, capacitive coupling through micro-machined diaphragms allowing resonator excitation at the package exterior, circuit integration and extremely small (0.1 in. square) dimensioning. A family of micro-miniature sensor beacons is also disclosed with widespread applications as bio-medical sensors, vehicle status monitors and high-volume animal identification and health sensors. The sensor family allows measurement of temperatures, chemicals, acceleration and pressure. A microphone and clock realization is also available. 21 figs.

[Assessment of mood disorders by passive data gathering: The concept of digital phenotype versus psychiatrist's professional culture].

PubMed

Bourla, A; Ferreri, F; Ogorzelec, L; Guinchard, C; Mouchabac, S

2018-04-01

The search for objective clinical signs is a constant practitioners' and researchers' concern in psychiatry. New technologies (embedded sensors, artificial intelligence) give an easier access to untapped information such as passive data (i.e. that do not require patient intervention). The concept of "digital phenotype" is emerging in psychiatry: a psychomotor alteration translated by accelerometer's modifications contrasting with the usual functioning of the subject, or the graphorrhea of patients presenting a manic episode which is replaced by an increase of SMS sent. Our main objective is to highlight the digital phenotype of mood disorders by means of a selective review of the literature. We conducted a selective review of the literature by querying the PubMed database until February 2017 with the terms [Computer] [Computerized] [Machine] [Automatic] [Automated] [Heart rate variability] [HRV] [actigraphy] [actimetry] [digital] [motion] [temperature] [Mood] [Bipolar] [Depression] [Depressive]. Eight hundred and forty-nine articles were submitted for evaluation, 37 articles were included. For unipolar disorders, smartphones can diagnose depression with excellent accuracy by combining GPS and call log data. Actigraphic measurements showing daytime alteration in basal function while ECG sensors assessing variation in heart rate variability (HRV) and body temperature appear to be useful tools to diagnose a depressive episode. For bipolar disorders, systems which combine several sensors are described: MONARCA, PRIORI, SIMBA and PSYCHE. All these systems combine passive and active data on smartphones. From a synthesis of these data, a digital phenotype of the disorders is proposed based on the accelerometer and the GPS, the ECG, the body temperature, the use of the smartphone and the voice. This digital phenotype thus brings into question certain clinical paradigms in which psychiatrists evolve. All these systems can be used to computerize the clinical characteristics of the various mental states studied, sometimes with greater precision than a clinician could do. Most authors recommend the use of passive data rather than active data in the context of bipolar disorders because automatically generated data reduce biases and limit the feeling of intrusion that self-questionnaires may cause. The impact of these technologies questions the psychiatrist's professional culture, defined as a specific language and a set of common values. We address issues related to these changes. Impact on psychiatrists could be important because their unity seems to be questioned due to technologies that profoundly modify the collect and process of clinical data. Copyright © 2017. Published by Elsevier Masson SAS.

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.

Investigation, Modeling and Validation of Digital Bridge for a New Generation Hot-Wire Anemometer

NASA Astrophysics Data System (ADS)

Joshi, Karthik Kamalakar

The Digital Bridge Thermal Anemometer (DBTA) is a new generation anemometer that uses advanced electronics and a modified half-Wheatstone bridge configuration, specifically a sensor and a shunt resistor in series. This allows the miniaturization of the anemometer and the communication between host computer and anemometer is carried out using serial or ethernet which eliminates the noise due to the use of long cables in conventional anemometer and the digital data sent to host computer is immune to electrical noise. In the new configuration the potential drop across a shunt resistor is used to control the bridge. This thesis is confined to the anemometer used in constant temperature (CT) mode. The heat transfer relations are studied and new expressions are developed based on the new configuration of the bridge using perturbation analysis. The theoretical plant model of a commercially available sensor and a custom built sensor are derived and quantified. The plant model is used to design a controller to control the plant in closed-loop using feedback. To test the performance of the modified sensor used with a "generation-I" bridge and DAQ, an experiment was conducted. The controller was implemented in a user interface in LabVIEW. The test is to compare the results between a conventional TSI sensor with an IFA 300 anemometer and the setup describe above, in the wake behind a circular cylinder. Performance of the DBTA is satisfactory at low frequencies. A user interface capable of communicating with the anemometer to control the operation and collect data generated by anemometer is developed in LabVIEW.

Smart Sensors for Launch Vehicles

NASA Astrophysics Data System (ADS)

Ray, Sabooj; Mathews, Sheeja; Abraham, Sheena; Pradeep, N.; Vinod, P.

2017-12-01

Smart Sensors bring a paradigm shift in the data acquisition mechanism adopted for launch vehicle telemetry system. The sensors integrate signal conditioners, digitizers and communication systems to give digital output from the measurement location. Multiple sensors communicate with a centralized node over a common digital data bus. An in-built microcontroller gives the sensor embedded intelligence to carry out corrective action for sensor inaccuracies. A smart pressure sensor has been realized and flight-proven to increase the reliability as well as simplicity in integration so as to obtain improved data output. Miniaturization is achieved by innovative packaging. This work discusses the construction, working and flight performance of such a sensor.

LANDSAT 4 band 6 data evaluation

NASA Technical Reports Server (NTRS)

1983-01-01

Satellite data collected over Lake Ontario were processed to observed surface temperature values. This involved computing apparent radiance values for each point where surface temperatures were known from averaged digital count values. These radiance values were then converted by using the LOWTRAN 5A atmospheric propagation model. This model was modified by incorporating a spectral response function for the LANDSAT band 6 sensors. A downwelled radiance term derived from LOWTRAN was included to account for reflected sky radiance. A blackbody equivalent source radiance was computed. Measured temperatures were plotted against the predicted temperature. The RMS error between the data sets is 0.51K.

Circuitry, systems and methods for detecting magnetic fields

DOEpatents

Kotter, Dale K [Shelley, ID; Spencer, David F [Idaho Falls, ID; Roybal, Lyle G [Idaho Falls, ID; Rohrbaugh, David T [Idaho Falls, ID

2010-09-14

Circuitry for detecting magnetic fields includes a first magnetoresistive sensor and a second magnetoresistive sensor configured to form a gradiometer. The circuitry includes a digital signal processor and a first feedback loop coupled between the first magnetoresistive sensor and the digital signal processor. A second feedback loop which is discrete from the first feedback loop is coupled between the second magnetoresistive sensor and the digital signal processor.

Digital pyramid wavefront sensor with tunable modulation.

PubMed

Akondi, Vyas; Castillo, Sara; Vohnsen, Brian

2013-07-29

The pyramid wavefront sensor is known for its high sensitivity and dynamic range that can be tuned by mechanically altering its modulation amplitude. Here, a novel modulating digital scheme employing a reflecting phase only spatial light modulator is demonstrated. The use of the modulator allows an easy reconfigurable pyramid with digital control of the apex angle and modulation geometry without the need of any mechanically moving parts. Aberrations introduced by a 140-actuator deformable mirror were simultaneously sensed with the help of a commercial Hartmann-Shack wavefront sensor. The wavefronts reconstructed using the digital pyramid wavefront sensor matched very closely with those sensed by the Hartmann-Shack. It is noted that a tunable modulation is necessary to operate the wavefront sensor in the linear regime and to accurately sense aberrations. Through simulations, it is shown that the wavefront sensor can be extended to astronomical applications as well. This novel digital pyramid wavefront sensor has the potential to become an attractive option in both open and closed loop adaptive optics systems.

An objective protocol for comparing the noise performance of silver halide film and digital sensor

NASA Astrophysics Data System (ADS)

Cao, Frédéric; Guichard, Frédéric; Hornung, Hervé; Tessière, Régis

2012-01-01

Digital sensors have obviously invaded the photography mass market. However, some photographers with very high expectancy still use silver halide film. Are they only nostalgic reluctant to technology or is there more than meets the eye? The answer is not so easy if we remark that, at the end of the golden age, films were actually scanned before development. Nowadays film users have adopted digital technology and scan their film to take advantage from digital processing afterwards. Therefore, it is legitimate to evaluate silver halide film "with a digital eye", with the assumption that processing can be applied as for a digital camera. The article will describe in details the operations we need to consider the film as a RAW digital sensor. In particular, we have to account for the film characteristic curve, the autocorrelation of the noise (related to film grain) and the sampling of the digital sensor (related to Bayer filter array). We also describe the protocol that was set, from shooting to scanning. We then present and interpret the results of sensor response, signal to noise ratio and dynamic range.

A Spacecraft Housekeeping System-on-Chip in a Radiation Hardened Structured ASIC

NASA Technical Reports Server (NTRS)

Suarez, George; DuMonthier, Jeffrey J.; Sheikh, Salman S.; Powell, Wesley A.; King, Robyn L.

2012-01-01

Housekeeping systems are essential to health monitoring of spacecraft and instruments. Typically, sensors are distributed across various sub-systems and data is collected using components such as analog-to-digital converters, analog multiplexers and amplifiers. In most cases programmable devices are used to implement the data acquisition control and storage, and the interface to higher level systems. Such discrete implementations require additional size, weight, power and interconnect complexity versus an integrated circuit solution, as well as the qualification of multiple parts. Although commercial devices are readily available, they are not suitable for space applications due the radiation tolerance and qualification requirements. The Housekeeping System-o n-A-Chip (HKSOC) is a low power, radiation hardened integrated solution suitable for spacecraft and instrument control and data collection. A prototype has been designed and includes a wide variety of functions including a 16-channel analog front-end for driving and reading sensors, analog-to-digital and digital-to-analog converters, on-chip temperature sensor, power supply current sense circuits, general purpose comparators and amplifiers, a 32-bit processor, digital I/O, pulse-width modulation (PWM) generators, timers and I2C master and slave serial interfaces. In addition, the device can operate in a bypass mode where the processor is disabled and external logic is used to control the analog and mixed signal functions. The device is suitable for stand-alone or distributed systems where multiple chips can be deployed across different sub-systems as intelligent nodes with computing and processing capabilities.

Precise color images a high-speed color video camera system with three intensified sensors

NASA Astrophysics Data System (ADS)

Oki, Sachio; Yamakawa, Masafumi; Gohda, Susumu; Etoh, Takeharu G.

1999-06-01

High speed imaging systems have been used in a large field of science and engineering. Although the high speed camera systems have been improved to high performance, most of their applications are only to get high speed motion pictures. However, in some fields of science and technology, it is useful to get some other information, such as temperature of combustion flame, thermal plasma and molten materials. Recent digital high speed video imaging technology should be able to get such information from those objects. For this purpose, we have already developed a high speed video camera system with three-intensified-sensors and cubic prism image splitter. The maximum frame rate is 40,500 pps (picture per second) at 64 X 64 pixels and 4,500 pps at 256 X 256 pixels with 256 (8 bit) intensity resolution for each pixel. The camera system can store more than 1,000 pictures continuously in solid state memory. In order to get the precise color images from this camera system, we need to develop a digital technique, which consists of a computer program and ancillary instruments, to adjust displacement of images taken from two or three image sensors and to calibrate relationship between incident light intensity and corresponding digital output signals. In this paper, the digital technique for pixel-based displacement adjustment are proposed. Although the displacement of the corresponding circle was more than 8 pixels in original image, the displacement was adjusted within 0.2 pixels at most by this method.

Effect of temperature on the characteristics of silicon nanowire transistor.

PubMed

Hashim, Yasir; Sidek, Othman

2012-10-01

This paper presents the temperature characteristics of silicon nanowire transistors (SiNWTs) and examines the effect of temperature on transfer characteristics, threshold voltage, I(ON)/I(OFF) ratio, drain-induced barrier lowering (DIBL), and sub-threshold swing (SS). The (MuGFET) simulation tool was used to investigate the temperature characteristics of a transistor. The findings reveal the negative effect of higher working temperature on the use of SiNWTs in electronic circuits, such as digital circuits and amplifiers circuits, because of the lower I(ON)/I(OFF) ratio, higher DIBL, and higher SS at higher temperature. Moreover, the ON state is the optimum condition for using a transistor as a temperature nano-sensor.

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

Comparison of the characteristics of small commercial NDIR CO2 sensor models and development of a portable CO2 measurement device.

PubMed

Yasuda, Tomomi; Yonemura, Seiichiro; Tani, Akira

2012-01-01

Many sensors have to be used simultaneously for multipoint carbon dioxide (CO(2)) observation. All the sensors should be calibrated in advance, but this is a time-consuming process. To seek a simplified calibration method, we used four commercial CO(2) sensor models and characterized their output tendencies against ambient temperature and length of use, in addition to offset characteristics. We used four samples of standard gas with different CO(2) concentrations (0, 407, 1,110, and 1,810 ppm). The outputs of K30 and AN100 models showed linear relationships with temperature and length of use. Calibration coefficients for sensor models were determined using the data from three individual sensors of the same model to minimize the relative RMS error. When the correction was applied to the sensors, the accuracy of measurements improved significantly in the case of the K30 and AN100 units. In particular, in the case of K30 the relative RMS error decreased from 24% to 4%. Hence, we have chosen K30 for developing a portable CO(2) measurement device (10 × 10 × 15 cm, 900 g). Data of CO(2) concentration, measurement time and location, temperature, humidity, and atmospheric pressure can be recorded onto a Secure Digital (SD) memory card. The CO(2) concentration in a high-school lecture room was monitored with this device. The CO(2) data, when corrected for simultaneously measured temperature, water vapor partial pressure, and atmospheric pressure, showed a good agreement with the data measured by a highly accurate CO(2) analyzer, LI-6262. This indicates that acceptable accuracy can be realized using the calibration method developed in this study.

Comparison of the Characteristics of Small Commercial NDIR CO2 Sensor Models and Development of a Portable CO2 Measurement Device

PubMed Central

Yasuda, Tomomi; Yonemura, Seiichiro; Tani, Akira

2012-01-01

Many sensors have to be used simultaneously for multipoint carbon dioxide (CO2) observation. All the sensors should be calibrated in advance, but this is a time-consuming process. To seek a simplified calibration method, we used four commercial CO2 sensor models and characterized their output tendencies against ambient temperature and length of use, in addition to offset characteristics. We used four samples of standard gas with different CO2 concentrations (0, 407, 1,110, and 1,810 ppm). The outputs of K30 and AN100 models showed linear relationships with temperature and length of use. Calibration coefficients for sensor models were determined using the data from three individual sensors of the same model to minimize the relative RMS error. When the correction was applied to the sensors, the accuracy of measurements improved significantly in the case of the K30 and AN100 units. In particular, in the case of K30 the relative RMS error decreased from 24% to 4%. Hence, we have chosen K30 for developing a portable CO2 measurement device (10 × 10 × 15 cm, 900 g). Data of CO2 concentration, measurement time and location, temperature, humidity, and atmospheric pressure can be recorded onto a Secure Digital (SD) memory card. The CO2 concentration in a high-school lecture room was monitored with this device. The CO2 data, when corrected for simultaneously measured temperature, water vapor partial pressure, and atmospheric pressure, showed a good agreement with the data measured by a highly accurate CO2 analyzer, LI-6262. This indicates that acceptable accuracy can be realized using the calibration method developed in this study. PMID:22737029

Harmful Gas Recognition Exploiting a CTL Sensor Array

PubMed Central

Wang, Qihui; Xie, Lijun; Zhu, Bo; Zheng, Yao; Cao, Shihua

2013-01-01

In this paper, a novel cataluminescence (CTL)-based sensor array consisting of nine types of catalytic materials is developed for the recognition of several harmful gases, namely carbon monoxide, acetone, chloroform and toluene. First, the experimental setup is constructed by using sensing nanomaterials, a heating plate, a pneumatic pump, a gas flow meter, a digital temperature device, a camera and a BPCL Ultra Weak Chemiluminescence Analyzer. Then, unique CTL patterns for the four types of harmful gas are obtained from the sensor array. The harmful gases are successful recognized by the PCA method. The optimal conditions are also investigated. Finally, experimental results show high sensitivity, long-term stability and good linearity of the sensor array, which combined with simplicity, make our system a promising application in this field. PMID:24113681

A Digital Solar Aspect Sensor

NASA Technical Reports Server (NTRS)

Albus, James S.

1961-01-01

The solar aspect sensor described herein performs the analog-to-digital conversion of data optically. To accomplish this, it uses a binary "Gray code" light mask to produce a digital indication, in vehicle-fixed coordinates, of the elevation and azimuth angles of incident light from the sun. This digital solar aspect sensor system, in Explorer X, provided measurements of both elevation and azimuth angles to +/- 2 degrees at a distance of over 140,000 statute miles.

Laboratory evaluation of the Design Analysis Associates DAA H-3613i radar water-level sensor—Results of temperature, distance, and SDI-12 tests

USGS Publications Warehouse

Carnley, Mark V.

2016-09-30

The Design Analysis Associates (DAA) DAA H-3613i radar water-level sensor (DAA H-3613i), manufactured by Xylem Incorporated, was evaluated by the U.S. Geological Survey (USGS) Hydrologic Instrumentation Facility (HIF) for conformance to manufacturer’s accuracy specifications for measuring a distance throughout the sensor’s operating temperature range, for measuring distances from 3 to 15 feet at ambient temperatures, and for compliance with the SDI-12 serial-to-digital interface at 1200-baud communication standard. The DAA H-3613i is a noncontact water-level sensor that uses pulsed radar to measure the distance between the radar and the water surface from 0.75 to 131 feet over a temperature range of −40 to 60 degrees Celsius (°C). Manufacturer accuracy specifications that were evaluated, the test procedures that followed, and the results obtained are described in this report. The sensor’s accuracy specification of ± 0.01 feet (± 3 millimeters) meets USGS requirements for a primary water-stage sensor used in the operation of a streamgage. The sensor met the manufacturer’s stated accuracy specifications for water-level measurements during temperature testing at a distance of 8 feet from the target over its temperature-compensated operating range of −40 to 60 °C, except at 60 °C. At 60 °C, about half the measurements exceeded the manufacturer’s accuracy specification by not more than 0.005 feet.The sensor met the manufacturer’s stated accuracy specifications for water-level measurements during distance-accuracy testing at the tested distances from 3 to 15 feet above the water surface at the HIF.

Digital Interface Modules for Active-Readout X-Ray Spectrometer.

DTIC Science & Technology

1985-03-01

strategy. Emitting a significant fraction of its total energy as complex series of high temperature characteristic x-ray lines, the PRS source is used for...0.001’ for the Reticon RL1024S detector). This is done by calculating the increment in photon energy dE that maps into a sensor width dg. The required...peak signal to r.m.s. noise). For most work the effects of temperature on the SSPA and other electronics will be more significant to the repeatability

Optical digitizing and strategies to combine different views of an optical sensor

NASA Astrophysics Data System (ADS)

Duwe, Hans P.

1997-09-01

Non-contact digitization of objects and surfaces with optical sensors based on fringe or pattern projection in combination with a CCD-camera allows a representation of surfaces with pointclouds equals x, y, z data points. To digitize the total surface of an object, it is necessary to combine the different measurement data obtained by the optical sensor from different views. Depending on the size of the object and the required accuracy of the measured data, different sensor set-ups with handling system or a combination of linear and rotation axes are described. Furthermore, strategies to match the overlapping pointclouds of a digitized object are introduced. This is very important especially for the digitization of large objects like 1:1 car models, etc. With different sensor sizes, it is possible to digitize small objects like teeth, crowns, inlays, etc. with an overall accuracy of 20 micrometer as well as large objects like car models, with a total accuracy of 0.5 mm. The various applications in the field of optical digitization are described.

Applying Digital Sensor Technology: A Problem-Solving Approach

ERIC Educational Resources Information Center

Seedhouse, Paul; Knight, Dawn

2016-01-01

There is currently an explosion in the number and range of new devices coming onto the technology market that use digital sensor technology to track aspects of human behaviour. In this article, we present and exemplify a three-stage model for the application of digital sensor technology in applied linguistics that we have developed, namely,…

Fiber Optic Control System Integration program: for optical flight control system development

NASA Astrophysics Data System (ADS)

Weaver, Thomas L.; Seal, Daniel W.

1994-10-01

Hardware and software were developed for optical feedback links in the flight control system of an F/A-18 aircraft. Developments included passive optical sensors and optoelectronics to operate the sensors. Sensors with different methods of operation were obtained from different manufacturers and integrated with common optoelectronics. The sensors were the following: Air Data Temperature; Air Data Pressure; and Leading Edge Flap, Nose Wheel Steering, Trailing Edge Flap, Pitch Stick, Rudder, Rudder Pedal, Stabilator, and Engine Power Lever Control Position. The sensors were built for a variety of aircraft locations and harsh environments. The sensors and optoelectronics were as similar as practical to a production system. The integrated system was installed by NASA for flight testing. Wavelength Division Multiplexing proved successful as a system design philosophy. Some sensors appeared to be better choices for aircraft applications than others, with digital sensors generally being better than analog sensors, and rotary sensors generally being better than linear sensors. The most successful sensor approaches were selected for use in a follow-on program in which the sensors will not just be flown on the aircraft and their performance recorded; but, the optical sensors will be used in closing flight control loops.

[Wireless Passive Body Sensor for Temperature Monitoring Using Near Field Communication Technology].

PubMed

Shi, Bo; Zhang, Li; Zhang, Genxuan; Tsau, Young; Zhang, Sai; Li, Lei

2017-01-01

In this study, we designed a wireless body temperature sensor (WBTS) based on near field communication (NFC) technology. Just attaching the WBTS to a mobile phone with NFC function, the real-time body temperature of human subjects can be acquired by an application program without seperate power supply. The WBTS is mainly composed of a digital body temperature probe (d-BTP), a NFC unit and an antenna. The d-BTP acquires and processes body temperature data through a micro control er, and the NFC unit and antenna are used for wireless energy transmission and data communication between the mobile phone and WBTS. UART communication protocol is used in the communication between the d-BTP and NFC unit, and data compression technique is adopted for improving transmission efficiency and decreasing power loss. In tests, the error of WBTS is ±0.1 oC, in range of 32 oC to 42 oC. The WBTS has advantages of high accuracy, low power loss, strong anti-interference ability, dispensation with independent power supply etc., and it can be integrated into wearable apparatuses for temperature monitoring and health management.

A Ratiometric Method for Johnson Noise Thermometry Using a Quantized Voltage Noise Source

NASA Astrophysics Data System (ADS)

Nam, S. W.; Benz, S. P.; Martinis, J. M.; Dresselhaus, P.; Tew, W. L.; White, D. R.

2003-09-01

Johnson Noise Thermometry (JNT) involves the measurement of the statistical variance of a fluctuating voltage across a resistor in thermal equilibrium. Modern digital techniques make it now possible to perform many functions required for JNT in highly efficient and predictable ways. We describe the operational characteristics of a prototype JNT system which uses digital signal processing for filtering, real-time spectral cross-correlation for noise power measurement, and a digitally synthesized Quantized Voltage Noise Source (QVNS) as an AC voltage reference. The QVNS emulates noise with a constant spectral density that is stable, programmable, and calculable in terms of known parameters using digital synthesis techniques. Changes in analog gain are accounted for by alternating the inputs between the Johnson noise sensor and the QVNS. The Johnson noise power at a known temperature is first balanced with a synthesized noise power from the QVNS. The process is then repeated by balancing the noise power from the same resistor at an unknown temperature. When the two noise power ratios are combined, a thermodynamic temperature is derived using the ratio of the two QVNS spectral densities. We present preliminary results where the ratio between the gallium triple point and the water triple point is used to demonstrate the accuracy of the measurement system with a standard uncertainty of 0.04 %.

A novel dynamic sensing of wearable digital textile sensor with body motion analysis.

PubMed

Yang, Chang-Ming; Lin, Zhan-Sheng; Hu, Chang-Lin; Chen, Yu-Shih; Ke, Ling-Yi; Chen, Yin-Rui

2010-01-01

This work proposes an innovative textile sensor system to monitor dynamic body movement and human posture by attaching wearable digital sensors to analyze body motion. The proposed system can display and analyze signals when individuals are walking, running, veering around, walking up and down stairs, as well as falling down with a wearable monitoring system, which reacts to the coordination between the body and feet. Several digital sensor designs are embedded in clothing and wear apparel. Any pressure point can determine which activity is underway. Importantly, wearable digital sensors and a wearable monitoring system allow adaptive, real-time postures, real time velocity, acceleration, non-invasive, transmission healthcare, and point of care (POC) for home and non-clinical environments.

Concept of a digital aerial platform for conducting observation flights under the open skies treaty. (Polish Title: Koncepcja cyfrowej platformy lotniczej do realizacji misji obserwacyjnych w ramach traktatu o otwartych przestworzach)

NASA Astrophysics Data System (ADS)

Walczykowski, P.; Orych, A.

2013-12-01

The Treaty on Open Skies, to which Poland is a signatory from the very beginning, was signed in 1992 in Helsinki. The main principle of the Treaty is increasing the openness of military activities conducted by the States-Parties and control over respecting disarmament agreements. Responsibilities given by the Treaty are fulfilled by conducting and receiving a given number of observation flights over the territories of the Treaty signatories. Among the 34 countries currently actively taking part in this Treaty only some own certified airplanes and observation sensors. Poland is within the group of countries who do not own their own platform and therefore fulfills Treaty requirements using the Ukrainian An-30b. Primarily, the Treaty only enabled the use of analogue sensors for the acquisition of imagery data. Together with the development of digital techniques, a rise in the need for digital imagery products had been noted. Currently digital photography is being used in almost ass fields of studies and everyday life. This has lead to very rapid developments in digital sensor technologies, employing the newest and most innovative solutions. Digital imagery products have many advantages and have now almost fully replaced traditional film sensors. Digital technologies have given rise to a new era in Open Skies. The Open Skies Consultative Commission, having conducted many series of tests, signed a new Decision to the Treaty, which allows for digital aerial sensors to be used during observation flights. The main aim of this article is to design a concept of choosing digital sensors and selecting an airplane, therefore a digital aerial platform, which could be used by Poland for Open Skies purposes. A thorough analysis of airplanes currently used by the Polish Air force was conducted in terms of their specifications and the possibility of their employment for Open Skies Treaty missions. Next, an analysis was conducted of the latest aerial digital sensors offered by leading commercial manufacturers. The sensors were analyzed in terms of the accordance of their specifications with the technical requirements of the Treaty.

Digital selective growth of a ZnO nanowire array by large scale laser decomposition of zinc acetate.

PubMed

Hong, Sukjoon; Yeo, Junyeob; Manorotkul, Wanit; Kang, Hyun Wook; Lee, Jinhwan; Han, Seungyong; Rho, Yoonsoo; Suh, Young Duk; Sung, Hyung Jin; Ko, Seung Hwan

2013-05-07

We develop a digital direct writing method for ZnO NW micro-patterned growth on a large scale by selective laser decomposition of zinc acetate. For ZnO NW growth, by replacing the bulk heating with the scanning focused laser as a fully digital local heat source, zinc acetate crystallites can be selectively activated as a ZnO seed pattern to grow ZnO nanowires locally on a larger area. Together with the selective laser sintering process of metal nanoparticles, more than 10,000 UV sensors have been demonstrated on a 4 cm × 4 cm glass substrate to develop all-solution processible, all-laser mask-less digital fabrication of electronic devices including active layer and metal electrodes without any conventional vacuum deposition, photolithographic process, premade mask, high temperature and vacuum environment.

CMOS Imaging of Temperature Effects on Pin-Printed Xerogel Sensor Microarrays.

PubMed

Lei Yao; Ka Yi Yung; Chodavarapu, Vamsy P; Bright, Frank V

2011-04-01

In this paper, we study the effect of temperature on the operation and performance of a xerogel-based sensor microarrays coupled to a complementary metal-oxide semiconductor (CMOS) imager integrated circuit (IC) that images the photoluminescence response from the sensor microarray. The CMOS imager uses a 32 × 32 (1024 elements) array of active pixel sensors and each pixel includes a high-gain phototransistor to convert the detected optical signals into electrical currents. A correlated double sampling circuit and pixel address/digital control/signal integration circuit are also implemented on-chip. The CMOS imager data are read out as a serial coded signal. The sensor system uses a light-emitting diode to excite target analyte responsive organometallic luminophores doped within discrete xerogel-based sensor elements. As a proto type, we developed a 3 × 3 (9 elements) array of oxygen (O2) sensors. Each group of three sensor elements in the array (arranged in a column) is designed to provide a different and specific sensitivity to the target gaseous O2 concentration. This property of multiple sensitivities is achieved by using a mix of two O2 sensitive luminophores in each pin-printed xerogel sensor element. The CMOS imager is designed to be low noise and consumes a static power of 320.4 μW and an average dynamic power of 624.6 μW when operating at 100-Hz sampling frequency and 1.8-V dc power supply.

A Wireless Biomedical Signal Interface System-on-Chip for Body Sensor Networks.

PubMed

Lei Wang; Guang-Zhong Yang; Jin Huang; Jinyong Zhang; Li Yu; Zedong Nie; Cumming, D R S

2010-04-01

Recent years have seen the rapid development of biosensor technology, system-on-chip design, wireless technology. and ubiquitous computing. When assembled into an autonomous body sensor network (BSN), the technologies become powerful tools in well-being monitoring, medical diagnostics, and personal connectivity. In this paper, we describe the first demonstration of a fully customized mixed-signal silicon chip that has most of the attributes required for use in a wearable or implantable BSN. Our intellectual-property blocks include low-power analog sensor interface for temperature and pH, a data multiplexing and conversion module, a digital platform based around an 8-b microcontroller, data encoding for spread-spectrum wireless transmission, and a RF section requiring very few off-chip components. The chip has been fully evaluated and tested by connection to external sensors, and it satisfied typical system requirements.

A solid-state digital temperature recorder for space use

NASA Technical Reports Server (NTRS)

Westbrook, R. M.; Bennett, L. D.; Steinhaver, R. A.; Deboo, G. J.

1981-01-01

A solid-state, digital, temperature recorder has been developed for use in space experiments. The recorder is completely self-contained and includes a temperature sensor; all necessary electronics for signal conditioning, processing, storing, control and timing; and a battery power supply. No electrical interfacing with the particular spacecraft on which the unit is used is required. The recorder is small, light, and sturdy, and has no moving parts. It uses only biocompatible materials and has passed vibration and shock spaceflight qualification tests. The unit is capable of storing 2048, -10 to +45 C, 8-bit temperature measurements taken at intervals selectable by factors of 2 from 1.875 to 240 min; data can be retained for at least 6 months. The basic recorder can be simplified to accommodate a variety of applications by adding memory to allow more data to be recorded, by changing the front end to permit measurements other than temperature to be made, and by using different batteries to realize various operating periods. Stored flight data are read out from the recorder by means of a ground read-out unit.

Curvature-correction-based time-domain CMOS smart temperature sensor with an inaccuracy of -0.8 °C-1.2 °C after one-point calibration from -40 °C to 120 °C

NASA Astrophysics Data System (ADS)

Chen, Chun-Chi; Lin, Shih-Hao; Lin, Yi

2014-06-01

This paper proposes a time-domain CMOS smart temperature sensor featuring on-chip curvature correction and one-point calibration support for thermal management systems. Time-domain inverter-based temperature sensors, which exhibit the advantages of low power and low cost, have been proposed for on-chip thermal monitoring. However, the curvature is large for the thermal transfer curve, which substantially affects the accuracy as the temperature range increases. Another problem is that the inverter is sensitive to process variations, resulting in difficulty for the sensors to achieve an acceptable accuracy for one-point calibration. To overcome these two problems, a temperature-dependent oscillator with curvature correction is proposed to increase the linearity of the oscillatory width, thereby resolving the drawback caused by a costly off-chip second-order master curve fitting. For one-point calibration support, an adjustable-gain time amplifier was adopted to eliminate the effect of process variations, with the assistance of a calibration circuit. The proposed circuit occupied a small area of 0.073 mm2 and was fabricated in a TSMC CMOS 0.35-μm 2P4M digital process. The linearization of the oscillator and the effect cancellation of process variations enabled the sensor, which featured a fixed resolution of 0.049 °C/LSB, to achieve an optimal inaccuracy of -0.8 °C to 1.2 °C after one-point calibration of 12 test chips from -40 °C to 120 °C. The power consumption was 35 μW at a sample rate of 10 samples/s.

Surface-acoustic-wave (SAW) flow sensor

NASA Astrophysics Data System (ADS)

Joshi, Shrinivas G.

1991-03-01

The use of a surface-acoustic-wave (SAW) device to measure the rate of gas flow is described. A SAW oscillator heated to a suitable temperature above ambient is placed in the path of a flowing gas. Convective cooling caused by the gas flow results in a change in the oscillator frequency. A 73-MHz oscillator fabricated on 128 deg rotated Y-cut lithium niobate substrate and heated to 55 C above ambient shows a frequency variation greater than 142 kHz for flow-rate variation from 0 to 1000 cu cm/min. The output of the sensor can be calibrated to provide a measurement of volume flow rate, pressure differential across channel ports, or mass flow rate. High sensitivity, wide dynamic range, and direct digital output are among the attractive features of this sensor. Theoretical expressions for the sensitivity and response time of the sensor are derived. It is shown that by using ultrasonic Lamb waves propagating in thin membranes, a flow sensor with faster response than a SAW sensor can be realized.

Surface-acoustic-wave (SAW) flow sensor.

PubMed

Joshi, S G

1991-01-01

The use of a surface-acoustic-wave (SAW) device to measure the rate of gas flow is described. A SAW oscillator heated to a suitable temperature above ambient is placed in the path of a flowing gas. Convective cooling caused by the gas flow results in a change in the oscillator frequency. A 73-MHz oscillator fabricated on 128 degrees rotated Y-cut lithium niobate substrate and heated to 55 degrees C above ambient shows a frequency variation greater than 142 kHz for flow-rate variation from 0 to 1000 cm(3)/min. The output of the sensor can be calibrated to provide a measurement of volume flow rate, pressure differential across channel ports, or mass flow rate. High sensitivity, wide dynamic range, and direct digital output are among the attractive features of this sensor. Theoretical expressions for the sensitivity and response time of the sensor are derived. It is shown that by using ultrasonic Lamb waves, propagating in thin membranes, a flow sensor with faster response than a SAW sensor can be realized.

Fluidic hydrogen detector production prototype development

NASA Technical Reports Server (NTRS)

Roe, G. W.; Wright, R. E.

1976-01-01

A hydrogen gas sensor that can replace catalytic combustion sensors used to detect leaks in the liquid hydrogen transfer systems at Kennedy Space Center was developed. A fluidic sensor concept, based on the principle that the frequency of a fluidic oscillator is proportional to the square root of the molecular weight of its operating fluid, was utilized. To minimize sensitivity to pressure and temperature fluctuations, and to make the sensor specific for hydrogen, two oscillators are used. One oscillator operates on sample gas containing hydrogen, while the other operates on sample gas with the hydrogen converted to steam. The conversion is accomplished with a small catalytic converter. The frequency difference is taken, and the hydrogen concentration computed with a simple digital processing circuit. The output from the sensor is an analog signal proportional to hydrogen content. The sensor is shown to be accurate and insensitive to severe environmental disturbances. It is also specific for hydrogen, even with large helium concentrations in the sample gas.

Image Processing Occupancy Sensor

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

The Image Processing Occupancy Sensor, or IPOS, is a novel sensor technology developed at the National Renewable Energy Laboratory (NREL). The sensor is based on low-cost embedded microprocessors widely used by the smartphone industry and leverages mature open-source computer vision software libraries. Compared to traditional passive infrared and ultrasonic-based motion sensors currently used for occupancy detection, IPOS has shown the potential for improved accuracy and a richer set of feedback signals for occupant-optimized lighting, daylighting, temperature setback, ventilation control, and other occupancy and location-based uses. Unlike traditional passive infrared (PIR) or ultrasonic occupancy sensors, which infer occupancy based only onmore » motion, IPOS uses digital image-based analysis to detect and classify various aspects of occupancy, including the presence of occupants regardless of motion, their number, location, and activity levels of occupants, as well as the illuminance properties of the monitored space. The IPOS software leverages the recent availability of low-cost embedded computing platforms, computer vision software libraries, and camera elements.« less

Superconductor Digital-RF Receiver Systems

NASA Astrophysics Data System (ADS)

Mukhanov, Oleg A.; Kirichenko, Dmitri; Vernik, Igor V.; Filippov, Timur V.; Kirichenko, Alexander; Webber, Robert; Dotsenko, Vladimir; Talalaevskii, Andrei; Tang, Jia Cao; Sahu, Anubhav; Shevchenko, Pavel; Miller, Robert; Kaplan, Steven B.; Sarwana, Saad; Gupta, Deepnarayan

Digital superconductor electronics has been experiencing rapid maturation with the emergence of smaller-scale, lower-cost communications applications which became the major technology drivers. These applications are primarily in the area of wireless communications, radar, and surveillance as well as in imaging and sensor systems. In these areas, the fundamental advantages of superconductivity translate into system benefits through novel Digital-RF architectures with direct digitization of wide band, high frequency radio frequency (RF) signals. At the same time the availability of relatively small 4K cryocoolers has lowered the foremost market barrier for cryogenically-cooled digital electronic systems. Recently, we have achieved a major breakthrough in the development, demonstration, and successful delivery of the cryocooled superconductor digital-RF receivers directly digitizing signals in a broad range from kilohertz to gigahertz. These essentially hybrid-technology systems combine a variety of superconductor and semiconductor technologies packaged with two-stage commercial cryocoolers: cryogenic Nb mixed-signal and digital circuits based on Rapid Single Flux Quantum (RSFQ) technology, room-temperature amplifiers, FPGA processing and control circuitry. The demonstrated cryocooled digital-RF systems are the world's first and fastest directly digitizing receivers operating with live satellite signals in X-band and performing signal acquisition in HF to L-band at ˜30GHz clock frequencies.

Sensors-network and its application in the intelligent storage security

NASA Astrophysics Data System (ADS)

Zhang, Qingying; Nicolescu, Mihai; Jiang, Xia; Zhang, Ying; Yue, Weihong; Xiao, Weihong

2004-11-01

Intelligent storage systems run on different advanced technologies, such as linear layout, business intelligence and data mining. Security, the basic desire of the storage system, has been focused on with the indraught of multimedia communication technology and sensors" network. Along with the developing of science and the social demands, multifarious alarming system has been designed and improved to be intelligentized, modularized and have network connections. It is of great moment to make the storage, and further more, the logistics system more and more efficient and perfect with modern science and technology. Diversified information on the spot should be caught by different kinds of sensors. Those signals are treated and communicated to the control center to give the further actions. For fire-proofing, broad-spectrum gas sensors, fume sensors, flame sensors and temperature sensors are used to catch the information in their own ways. Once the fire is taken somewhere, the sensors work by the fume, temperature, and flame as well as gas immediately. Meanwhile the intelligent control system starts. It passes the tidings to the center unit. At the same time, it sets those movable walls on to work quickly to obstruct the fire"s spreading. While for guarding the warehouse against theft, cut-off sensors, body sensors, photoelectric sensors, microwave sensors and closed-circuit television as well as electronic clocks are available to monitor the warehouse reasonably. All of those sensors work in a net way. The intelligent control system is made with a digital circuit instead of traditional switch one. This system can work in a better way in many cases. Its reliability is high and the cost is low.

Navigation and Elctro-Optic Sensor Integration Technology for Fusion of Imagery and Digital Mapping Products

DTIC Science & Technology

1999-08-01

Electro - Optic Sensor Integration Technology (NEOSIT) software application. The design is highly modular and based on COTS tools to facilitate integration with sensors, navigation and digital data sources already installed on different host

Combined holography and thermography in a single sensor through image-plane holography at thermal infrared wavelengths.

PubMed

Georges, Marc P; Vandenrijt, Jean-François; Thizy, Cédric; Alexeenko, Igor; Pedrini, Giancarlo; Vollheim, Birgit; Lopez, Ion; Jorge, Iagoba; Rochet, Jonathan; Osten, Wolfgang

2014-10-20

Holographic interferometry in the thermal wavelengths range, combining a CO(2) laser and digital hologram recording with a microbolometer array based camera, allows simultaneously capturing temperature and surface shape information about objects. This is due to the fact that the holograms are affected by the thermal background emitted by objects at room temperature. We explain the setup and the processing of data which allows decoupling the two types of information. This natural data fusion can be advantageously used in a variety of nondestructive testing applications.

Design and implementation of a Bluetooth-based infant monitoring/saver (BIMS) system

NASA Astrophysics Data System (ADS)

Sonmez, Ahmet E.; Nalcaci, Murat T.; Pazarbasi, Mehmet A.; Toker, Onur; Fidanboylu, Kemal

2007-04-01

In this work, we discuss the design and implementation of a Bluetooth technology based infant monitoring system, which will enable the mother to monitor her baby's health condition remotely in real-time. The system will measure the heart rate, and temperature of the infant, and stream this data to the mother's Bluetooth based mobile unit, e.g. cell phone, PDA, etc. Existing infant monitors either require so many cables, or transmit only voice and/or video information, which is not enough for monitoring the health condition of an infant. With the proposed system, the mother will be warned against any abnormalities, which may be an indication of a disease, which in turn may result a sudden infant death. High temperature is a common symptom for several diseases, and heart rate is an essential sign of life, low or high heart rates are also essentials symptoms. Because of these reasons, the proposed system continously measures these two critical values. A 12 bits digital temperature sensor is used to measure infant's body temperature, and a piezo film sensor is used measure infant's heartbeat rate. These sensors, some simple analog circuitry, and a ToothPick unit are the main components of our embedded system. ToothPick unit is basically a Microchip 18LF6720 microcontroller, plus an RF circuitry with Bluetooth stack.

Development of a low-cost temperature data monitoring. An upgrade for hot box apparatus

NASA Astrophysics Data System (ADS)

de Rubeis, T.; Nardi, I.; Muttillo, M.

2017-11-01

The monitoring phase has gained a fundamental role in the energy efficiency evaluation of a system. Number and typology of the probes depend on the physical quantity to be monitored, and on the size and complexity of the system. Moreover, a measurement equipment should be designed to allow the employment of probes different for number and measured physical quantities. For this reason, a scalable equipment represents a good way for easily carrying out a system monitoring. Proprietary software and high costs characterize instruments of current use, thus limiting the possibilities to realize customized monitoring. In this paper, a temperature measuring instrument, conceived, designed, and realized for real time applications, is presented. The proposed system is based on digital thermometers and on open-source code. A remarkable feature of the instrument is the possibility of acquiring data from a high and variable number of probes (order of hundred), assuring flexibility of the software, since it can be programmed, and low-cost of the hardware components. The contemporary use of multiple temperature probes suggested to apply this instrument for a hot box apparatus, although the software can be set for recording different physical quantities. A hot box compliant with standard EN ISO 8990 should be equipped with several temperature probes to investigate heat exchanges of a specimen wall and thermal field of the chambers. In this work, preliminary tests have been carried out focusing only on the evaluation of the prototypal system’s performance. The tests were realized by comparing different sensors, such as thermocouples and resistance thermometers, traditionally employed in hot box experiments. A preliminary test was realized imposing a dynamic condition with a thermoelectric Peltier cell. Data obtained by digital thermometers DS18B20, compared with the ones of Pt100 probes, show a good correlation. Based on these encouraging results, a further test was carried out in hot box, comparing the data measured by digital thermometers, Pt100 and T-type thermocouples. In this case also, the analyses show a good correlation between either digital thermometers and analog sensors. From these results, it is reasonable to foresee that this measuring instrument could help those willing to realize or refurbish a hot box apparatus, and those who want to undertake temperature monitoring.

Evaluation of Xylem EXO water-quality sondes and sensors

USGS Publications Warehouse

Snazelle, Teri T.

2015-01-01

Two models of multiparameter sondes manufactured by Xylem, parent company of Yellow Springs Incorporated (YSI)—EXO1 and EXO2—equipped with EXO conductivity/temperature (C/T), pH, dissolved oxygen (DO), and turbidity sensors, were evaluated by the U.S. Geological Survey (USGS) Hydrologic Instrumentation Facility. The sondes and sensors were evaluated in two phases for compliance with the manufacturer’s specifications and the USGS acceptance criteria for continuous water-quality monitors. Phase one tested the accuracy of the water-quality sondes equipped: (a) with a C/T, pH, DO, and turbidity sensor by comparing the EXO sensors’ measured values to those of an equivalently configured YSI 6920 V2-2 sensor, and (b) with multiple sensors of the same parameter type (such as three pH sensors and a C/T sensor) on a single sonde at room temperature and at an extended temperature range. In addition to accuracy, the communication protocols and the manufacturing specifications for range of detection and operating temperature were also tested during this phase. Phase two evaluated the sondes’ performance in a surface-water environment by deploying an EXO1 and an EXO2 equipped with pH, C/T, DO, and turbidity sensors at USGS site 02492620 located at East Pearl River near Bay Saint Louis, Mississippi. The EXO sondes’ temperature deviations from a certified YSI 4600 digital thermometer were within the ±0.2 degree Celsius (°C) USGS criteria, but were greater than the ±0.01 °C manufacturing specification. The conductivity sensors met the ±3 percent USGS criteria for specific conductance greater than 100 microsiemens per centimeter. The sensors met the more stringent ±0.5 percent manufacturing specification only at room temperature in the 250 microsiemens per centimeter (µS/cm) standard. The manufacturing and USGS criteria (±0.2 pH unit) were met in pH standards 4, 9.2, 10, and 12.45, but were not met in pH 1.68 standard. The DO sensors met both the ±0.3 milligram per liter (mg/L) USGS criteria and the ±1 percent manufacturing specification. The ±5 percent USGS criteria for turbidity in waters not exceeding 2,000 formazin nephelometric units (FNU) were met by the five turbidity sensors tested; however, all five sensors failed to meet these requirements at turbidities exceeding 2,000 FNU. The more stringent ±2 percent manufacturing turbidity specification for water with less than 1,000 FNU was met by only one of the five sensors tested. The results from the field deployment indicated acceptable agreement in temperature, specific conductance, pH, and DO between the EXO sondes, the site sonde, and the reference sonde. The EXO1 and EXO2 turbidity measurements differed from the site sonde by approximately 23 and 25 percent, respectively.

A Fully Integrated Sensor SoC with Digital Calibration Hardware and Wireless Transceiver at 2.4 GHz

PubMed Central

Kim, Dong-Sun; Jang, Sung-Joon; Hwang, Tae-Ho

2013-01-01

A single-chip sensor system-on-a-chip (SoC) that implements radio for 2.4 GHz, complete digital baseband physical layer (PHY), 10-bit sigma-delta analog-to-digital converter and dedicated sensor calibration hardware for industrial sensing systems has been proposed and integrated in a 0.18-μm CMOS technology. The transceiver's building block includes a low-noise amplifier, mixer, channel filter, receiver signal-strength indicator, frequency synthesizer, voltage-controlled oscillator, and power amplifier. In addition, the digital building block consists of offset quadrature phase-shift keying (OQPSK) modulation, demodulation, carrier frequency offset compensation, auto-gain control, digital MAC function, sensor calibration hardware and embedded 8-bit microcontroller. The digital MAC function supports cyclic redundancy check (CRC), inter-symbol timing check, MAC frame control, and automatic retransmission. The embedded sensor signal processing block consists of calibration coefficient calculator, sensing data calibration mapper and sigma-delta analog-to-digital converter with digital decimation filter. The sensitivity of the overall receiver and the error vector magnitude (EVM) of the overall transmitter are −99 dBm and 18.14%, respectively. The proposed calibration scheme has a reduction of errors by about 45.4% compared with the improved progressive polynomial calibration (PPC) method and the maximum current consumption of the SoC is 16 mA. PMID:23698271

An automated digital imaging system for environmental monitoring applications

USGS Publications Warehouse

Bogle, Rian; Velasco, Miguel; Vogel, John

2013-01-01

Recent improvements in the affordability and availability of high-resolution digital cameras, data loggers, embedded computers, and radio/cellular modems have advanced the development of sophisticated automated systems for remote imaging. Researchers have successfully placed and operated automated digital cameras in remote locations and in extremes of temperature and humidity, ranging from the islands of the South Pacific to the Mojave Desert and the Grand Canyon. With the integration of environmental sensors, these automated systems are able to respond to local conditions and modify their imaging regimes as needed. In this report we describe in detail the design of one type of automated imaging system developed by our group. It is easily replicated, low-cost, highly robust, and is a stand-alone automated camera designed to be placed in remote locations, without wireless connectivity.

A novel proposal of GPON-oriented fiber grating sensing data digitalization system for remote sensing network

NASA Astrophysics Data System (ADS)

Wang, Yubao; Zhu, Zhaohui; Wang, Lu; Bai, Jian

2016-05-01

A novel GPON-oriented sensing data digitalization system is proposed to achieve remote monitoring of fiber grating sensing networks utilizing existing optical communication networks in some harsh environments. In which, Quick digitalization of sensing information obtained from the reflected lightwaves by fiber Bragg grating (FBG) sensor is realized, and a novel frame format of sensor signal is designed to suit for public transport so as to facilitate sensor monitoring center to receive and analyze the sensor data. The delay effect, identification method of the sensor data, and various interference factors which influence the sensor data to be correctly received are analyzed. The system simulation is carried out with OptiSystem/Matlab co-simulation approach. The theoretical analysis and simulation results verify the feasibility of the integration of the sensor network and communication network.

Sensitive bistable magnetic sensors using twisted amorphous magnetostrictive ribbons due to Matteucci effect

NASA Astrophysics Data System (ADS)

Mohri, K.; Takeuchi, S.

1982-11-01

New sensitive magnetic-field sensors are presented using twisted amorphous magnetostrictive ribbons such as Fe80B20 and Fe81-xCrxB17Si2. Sharp voltage pulses are induced between ends of the ribbon of as short as 25 mm or at the terminals of the detecting coil against external fields of as low as 1 Oe and 0.01 Hz-6 kHz. The domain nucleation field at the bistable flux reversal is very constant for 130 °C, 600 h using Fe79Cr2B17Si2, and a possible maximum operating temperature is about 180 °C. Small sized magnetic sensors without any windings for detecting rotational speed, distance, and other mechanical quantities are realized using the twisted ribbons by combining with small magnets. These sensitive and reliable magnetic sensors with digital outputs are suitable for applications in industrial robots and automobiles controlled with microcomputers.

Experimental studies in natural groundwater recharge dynamics: Assessment of recent advances in instrumentation

USGS Publications Warehouse

Sophocleous, M.; Perry, C.A.

1984-01-01

To quantify and model the natural groundwater-recharge process, two sites in south-central Kansas, U.S.A., were instrumented with various modern sensors and data microloggers. The atmospheric-boundary layer and the unsaturated and saturated soil zones were monitored as a unified regime. Data from the various sensors were collected using microloggers in combination with magnetic-cassette tape, graphical and digital recorders, analog paper-tape recorders, and direct observations to evaluate and automate data collection and processing. Atmospheric sensors included an anemometer, a tipping-bucket raingage, an air-temperature thermistor, a relative-humidity probe, a net radiometer, and a barometric-pressure transducer. Sensors in the unsaturated zone consisted of soil-temperature thermocouples, tensiometers coupled with pressure transducers and dial gages, gypsum blocks, and a neutron moisture probe operated by an observer. The saturated-zone sensors consisted of a water-level pressure transducer, a conventional float gage connected to a variable potentiometer, soil thermocouples, and a number of multiple-depth piezometers. Evaluation of the operation of these sensors and recorders indicated that certain types of equipment such as pressure transducers are very sensitive to environmental conditions. Extraordinary steps had to be taken to protect some of the equipment, whereas other equipment seemed to be reliable under all conditions. Based on such experiences, a number of suggestions aimed at improving such investigations are outlined. ?? 1984.

Deployment of quasi-digital sensor for high temperature molten salt level measurement in pyroprocessing plants.

PubMed

Sanga, Ramesh; Agarwal, Sourabh; Sivaramakrishna, M; Rao, G Prabhakara

2018-04-01

Development of a liquid molten salt level sensor device that can detect the level of liquid molten salt in the process vessels of pyrochemical reprocessing of spent metallic fuels is detailed. It is proposed to apply a resistive-type pulsating sensor-based level measurement approach. There are no commercially available sensors due to limitations of high temperature, radiation, and physical dimensions. A compact, simple, rugged, low power, and high precise pulsating sensor-based level probe and simple instrumentation for the molten salt liquid level sensor to work in the extreme conditions has been indigenously developed, with high precision and accuracy. The working principle, design concept, and results have been discussed. This level probe is mainly composed of the variable resistor made up of ceramic rods. This resistor constitutes the part of resistance-capacitance-type Logic Gate Oscillator (LGO). A change in the molten salt level inside the tank causes a small change in the resistance which in turn changes the pulse frequency of the LGO. Thus the frequency, the output of the instrument that is displayed on the LCD of an embedded system, is a function of molten salt level. In the present design, the range of level measurement is about 10 mm. The sensitivity in position measurement up to 10 mm is ∼2.5 kHz/mm.

Deployment of quasi-digital sensor for high temperature molten salt level measurement in pyroprocessing plants

NASA Astrophysics Data System (ADS)

Sanga, Ramesh; Agarwal, Sourabh; Sivaramakrishna, M.; Rao, G. Prabhakara

2018-04-01

Development of a liquid molten salt level sensor device that can detect the level of liquid molten salt in the process vessels of pyrochemical reprocessing of spent metallic fuels is detailed. It is proposed to apply a resistive-type pulsating sensor-based level measurement approach. There are no commercially available sensors due to limitations of high temperature, radiation, and physical dimensions. A compact, simple, rugged, low power, and high precise pulsating sensor-based level probe and simple instrumentation for the molten salt liquid level sensor to work in the extreme conditions has been indigenously developed, with high precision and accuracy. The working principle, design concept, and results have been discussed. This level probe is mainly composed of the variable resistor made up of ceramic rods. This resistor constitutes the part of resistance-capacitance-type Logic Gate Oscillator (LGO). A change in the molten salt level inside the tank causes a small change in the resistance which in turn changes the pulse frequency of the LGO. Thus the frequency, the output of the instrument that is displayed on the LCD of an embedded system, is a function of molten salt level. In the present design, the range of level measurement is about 10 mm. The sensitivity in position measurement up to 10 mm is ˜2.5 kHz/mm.

Development and Commissioning Results of the Hybrid Sensor Bus Engineering Qualification Model

NASA Astrophysics Data System (ADS)

Hurni, Andreas; Putzer, Phillipp; Roner, Markus; Gurster, Markus; Hulsemeyer, Christian; Lemke, Norbert M. K.

2016-08-01

In order to reduce mass, AIT effort and overall costs of classical point-to-point wired temperature sensor harness on-board spacecraft OHB System AGhas introduced the Hybrid Sensor Bus (HSB) system which interrogates sensors connected in a bus architecture. To use the advantages of electrical as wellas of fiber-optical sensing technologies, HSB is designed as a modular measurement system interrogating digital sensors connected on electricalsensor buses based on I2C and fiber-optical sensor buses based on fiber Bragg grating (FBG) sensors inscribed in optical fibers. Fiber-optical sensor bus networks on-board satellites are well suited for temperature measurement due to low mass, electro-magnetic insensitivity and the capability to embed them inside structure parts. The lightweight FBG sensors inscribed in radiation tolerant fibers can reach every part of the satellite. HSB has been developed in the frame of the ESA ARTES program with European and German co- funding and will be verified as flight demonstrator on- board the German Heinrich Hertz satellite (H2Sat).In this paper the Engineering Qualification Model (EQM) development of HSB and first commissioning results are presented. For the HSB development requirements applicable for telecommunication satellite platforms have been considered. This includes an operation of at least 15 years in a geostationary orbit.In Q3/2016 the qualification test campaign is planned to be carried out. The HSB EQM undergoes a full qualification according to ECSS. The paper concludes with an outlook regarding this HSB flight demonstrator development and its in-orbit verification (IOV) on board H2Sat.

Multi-purpose CMOS sensor interface for low-power applications

NASA Astrophysics Data System (ADS)

Wouters, P.; de Cooman, M.; Puers, R.

1994-08-01

A dedicated low-power CMOS transponder microchip is presented as part of a novel telemetry implant for biomedical applications. This mixed analog-digital circuit contains an identification code and collects information on physiological parameters, i.e., body temperature and physical activity, and on the status of the battery. To minimize the amount of data to be transmitted, a dedicated signal processing algorithm is embedded within its circuitry. All telemetry functions (encoding, modulation, generation of the carrier) are implemented on the integrated circuit. Emphasis is on a high degree of flexibility towards sensor inputs and internal data management, extreme miniaturization, and low-power consumption to allow a long implantation lifetime.

A novel CMOS image sensor system for quantitative loop-mediated isothermal amplification assays to detect food-borne pathogens.

PubMed

Wang, Tiantian; Kim, Sanghyo; An, Jeong Ho

2017-02-01

Loop-mediated isothermal amplification (LAMP) is considered as one of the alternatives to the conventional PCR and it is an inexpensive portable diagnostic system with minimal power consumption. The present work describes the application of LAMP in real-time photon detection and quantitative analysis of nucleic acids integrated with a disposable complementary-metal-oxide semiconductor (CMOS) image sensor. This novel system works as an amplification-coupled detection platform, relying on a CMOS image sensor, with the aid of a computerized circuitry controller for the temperature and light sources. The CMOS image sensor captures the light which is passing through the sensor surface and converts into digital units using an analog-to-digital converter (ADC). This new system monitors the real-time photon variation, caused by the color changes during amplification. Escherichia coli O157 was used as a proof-of-concept target for quantitative analysis, and compared with the results for Staphylococcus aureus and Salmonella enterica to confirm the efficiency of the system. The system detected various DNA concentrations of E. coli O157 in a short time (45min), with a detection limit of 10fg/μL. The low-cost, simple, and compact design, with low power consumption, represents a significant advance in the development of a portable, sensitive, user-friendly, real-time, and quantitative analytic tools for point-of-care diagnosis. Copyright © 2016 Elsevier B.V. All rights reserved.

Optical fiber pressure sensors for adaptive wings

NASA Astrophysics Data System (ADS)

Duncan, Paul G.; Jones, Mark E.; Shinpaugh, Kevin A.; Poland, Stephen H.; Murphy, Kent A.; Claus, Richard O.

1997-06-01

Optical fiber pressure sensors have been developed for use on a structurally-adaptive `smart wing'; further details of the design, fabrication and testing of the smart wing concept are presented in companion papers. This paper describes the design, construction, and performance of the pressure sensor and a combined optical and electronic signal processing system implemented to permit the measurement of a large number of sensors distributed over the control surfaces of a wing. Optical fiber pressure sensors were implemented due to anticipated large electromagnetic interference signals within the operational environment. The sensors utilized the principle of the extrinsic Fabry-Perot interferometer (EFPI) already developed for the measurement of strain and temperature. Here, the cavity is created inside a micromachined hollow-core tube with a silicon diaphragm at one end. The operation of the sensor is similar to that of the EFPI strain gage also discussed in several papers at this conference. The limitations placed upon the performance of the digital signal processing system were determined by the required pressure range of the sensors and the cycle time of the control system used to adaptively modify the shape of the wing. Sensor calibration and the results of testing performed are detailed.

A permanent seismic station beneath the Ocean Bottom

NASA Astrophysics Data System (ADS)

Harris, David; Cessaro, Robert K.; Duennebier, Fred K.; Byrne, David A.

1987-03-01

The Hawaii Institute of Geophysics began development of the Ocean Subbottom Seisometer (OSS) system in 1978, and OSS systems were installed in four locations between 1979 and 1982. The OSS system is a permanent, deep ocean borehole seismic recording system composed of a borehole sensor package (tool), an electromechanical cable, recorder package, and recovery system. Installed near the bottom of a borehole (drilled by the D/V Glomar Challenger), the tool contains three orthogonal, 4.5-Hz geophones, two orthogonal tilt meters; and a temperature sensor. Signals from these sensors are multiplexed, digitized (with a floating point technique), and telemetered through approximately 10 km of electromechanical cable to a recorder package located near the ocean bottom. Electrical power for the tool is supplied from the recorder package. The digital seismic signals are demultiplexed, converted back to analog form, processed through an automatic gain control (AGC) circuit, and recorded along with a time code on magnetic tape cassettes in the recorder package. Data may be recorded continuously for up to two months in the self-contained recorder package. Data may also be recorded in real time (digital formal) during the installation and subsequent recorder package servicing. The recorder package is connected to a submerged recovery buoy by a length of bouyant polypropylene rope. The anchor on the recovery buoy is released by activating either of the acoustical command releases. The polypropylene rope may also be seized with a grappling hook to effect recovery. The recorder package may be repeatedly serviced as long as the tool remains functional A wide range of data has been recovered from the OSS system. Recovered analog records include signals from natural seismic sources such as earthquakes (teleseismic and local), man-made seismic sources such as refraction seismic shooting (explosives and air cannons), and nuclear tests. Lengthy continuous recording has permitted analysis of wideband noise levels, and the slowly varying parameters, temperature and tilt.

Timing Results Using an FPGA-Based TDC with Large Arrays of 144 SiPMs

NASA Astrophysics Data System (ADS)

Aguilar, A.; González, A. J.; Torres, J.; García-Olcina, R.; Martos, J.; Soret, J.; Conde, P.; Hernández, L.; Sánchez, F.; Benlloch, J. M.

2015-02-01

Silicon photomultipliers (SiPMs) have become an alternative to traditional tubes due to several features. However, their implementation to form large arrays is still a challenge especially due to their relatively high intrinsic noise, depending on the chosen readout. In this contribution, two modules composed of 12 ×12 SiPMs with an area of roughly 50 mm×50 mm are used in coincidence. Coincidence resolving time (CRT) results with a field-programmable gate array, in combination with a time to digital converter, are shown as a function of both the sensor bias voltage and the digitizer threshold. The dependence of the CRT on the sensor matrix temperature, the amount of SiPM active area and the crystal type is also analyzed. Measurements carried out with a crystal array of 2 mm pixel size and 10 mm height have shown time resolutions for the entire 288 SiPM two-detector set-up as good as 800 ps full width at half maximum (FWHM).

Data Transfer for Multiple Sensor Networks Over a Broad Temperature Range

NASA Technical Reports Server (NTRS)

Krasowski, Michael

2013-01-01

At extreme temperatures, cryogenic and over 300 C, few electronic components are available to support intelligent data transfer over a common, linear combining medium. This innovation allows many sensors to operate on the same wire bus (or on the same airwaves or optical channel: any linearly combining medium), transmitting simultaneously, but individually recoverable at a node in a cooler part of the test area. This innovation has been demonstrated using room-temperature silicon microcircuits as proxy. The microcircuits have analog functionality comparable to componentry designed using silicon carbide. Given a common, linearly combining medium, multiple sending units may transmit information simultaneously. A listening node, using various techniques, can pick out the signal from a single sender, if it has unique qualities, e.g. a voice. The problem being solved is commonly referred to as the cocktail party problem. The human brain uses the cocktail party effect when it is able to recognize and follow a single conversation in a party full of talkers and other noise sources. High-temperature sensors have been used in silicon carbide electronic oscillator circuits. The frequency of the oscillator changes as a function of the changes in the sensed parameter, such as pressure. This change is analogous to changes in the pitch of a person s voice. The output of this oscillator and many others may be superimposed onto a single medium. This medium may be the power lines supplying current to the sensors, a third wire dedicated to data transmission, the airwaves through radio transmission, an optical medium, etc. However, with nothing to distinguish the identities of each source that is, the source separation this system is useless. Using digital electronic functions, unique codes or patterns are created and used to modulate the output of the sensor.

Inexpensive Open-Source Data Logging in the Field

NASA Astrophysics Data System (ADS)

Wickert, A. D.

2013-12-01

I present a general-purpose open-source field-capable data logger, which provides a mechanism to develop dense networks of inexpensive environmental sensors. This data logger was developed as a low-power variant of the Arduino open-source development system, and is named the ALog ("Arduino Logger") BottleLogger (it is slim enough to fit inside a Nalgene water bottle) version 1.0. It features an integrated high-precision real-time clock, SD card slot for high-volume data storage, and integrated power switching. The ALog can interface with sensors via six analog/digital pins, two digital pins, and one digital interrupt pin that can read event-based inputs, such as those from a tipping-bucket rain gauge. We have successfully tested the ALog BottleLogger with ultrasonic rangefinders (for water stage and snow accumulation and melt), temperature sensors, tipping-bucket rain gauges, soil moisture and water potential sensors, resistance-based tools to measure frost heave, and cameras that it triggers based on events. The source code for the ALog, including functions to interface with a a range of commercially-available sensors, is provided as an Arduino C++ library with example implementations. All schematics, circuit board layouts, and source code files are open-source and freely available under GNU GPL v3.0 and Creative Commons Attribution-ShareAlike 3.0 Unported licenses. Through this work, we hope to foster a community-driven movement to collect field environmental data on a budget that permits citizen-scientists and researchers from low-income countries to collect the same high-quality data as researchers in wealthy countries. These data can provide information about global change to managers, governments, scientists, and interested citizens worldwide. Watertight box with ALog BottleLogger data logger on the left and battery pack with 3 D cells on the right. Data can be collected for 3-5 years on one set of batteries.

Soldier systems sensor fusion

NASA Astrophysics Data System (ADS)

Brubaker, Kathryne M.

1998-08-01

This paper addresses sensor fusion and its applications in emerging Soldier Systems integration and the unique challenges associated with the human platform. Technology that,provides the highest operational payoff in a lightweight warrior system must not only have enhanced capabilities, but have low power components resulting in order of magnitude reductions coupled with significant cost reductions. These reductions in power and cost will be achieved through partnership with industry and leveraging of commercial state of the art advancements in microelectronics and power sources. As new generation of full solution fire control systems (to include temperature, wind and range sensors) and target acquisition systems will accompany a new generation of individual combat weapons and upgrade existing weapon systems. Advanced lightweight thermal, IR, laser and video senors will be used for surveillance, target acquisition, imaging and combat identification applications. Multifunctional sensors will provide embedded training features in combat configurations allowing the soldier to 'train as he fights' without the traditional cost and weight penalties associated with separate systems. Personal status monitors (detecting pulse, respiration rate, muscle fatigue, core temperature, etc.) will provide commanders and highest echelons instantaneous medical data. Seamless integration of GPS and dead reckoning (compass and pedometer) and/or inertial sensors will aid navigation and increase position accuracy. Improved sensors and processing capability will provide earlier detection of battlefield hazards such as mines, enemy lasers and NBC (nuclear, biological, chemical) agents. Via the digitized network the situational awareness database will automatically be updated with weapon, medical, position and battlefield hazard data. Soldier Systems Sensor Fusion will ultimately establish each individual soldier as an individual sensor on the battlefield.

Fast Low-Cost Multiple Sensor Readout System

DOEpatents

Carter-Lewis, David; Krennich, Frank; Le Bohec, Stephane; Petry, Dirk; Sleege, Gary

2004-04-06

A low resolution data acquisition system is presented. The data acquisition system has a plurality of readout modules serially connected to a controller. Each readout module has a FPGA in communication with analog to digital (A/D) converters, which are connected to sensors. The A/D converter has eight bit or lower resolution. The FPGA detects when a command is addressed to it and commands the A/D converters to convert analog sensor data into digital data. The digital data is sent on a high speed serial communication bus to the controller. A graphical display is used in one embodiment to indicate if a sensor reading is outside of a predetermined range.

Wireless Zigbee strain gage sensor system for structural health monitoring

NASA Astrophysics Data System (ADS)

Ide, Hiroshi; Abdi, Frank; Miraj, Rashid; Dang, Chau; Takahashi, Tatsuya; Sauer, Bruce

2009-05-01

A compact cell phone size radio frequency (ZigBee) wireless strain measurement sensor system to measure the structural strain deformation was developed. The developed system provides an accurate strain measurement data stream to the Internet for further Diagnostic and Prognostic (DPS) correlation. Existing methods of structural measurement by strain sensors (gauges) do not completely satisfy problems posed by continuous structural health monitoring. The need for efficient health monitoring methods with real-time requirements to bidirectional data flow from sensors and to a commanding device is becoming critical for keeping our daily life safety. The use of full-field strain measurement techniques could reduce costly experimental programs through better understanding of material behavior. Wireless sensor-network technology is a monitoring method that is estimated to grow rapidly providing potential for cost savings over traditional wired sensors. The many of currently available wireless monitoring methods have: the proactive and constant data rate character of the data streams rather than traditional reactive, event-driven data delivery; mostly static node placement on structures with limited number of nodes. Alpha STAR Electronics' wireless sensor network system, ASWN, addresses some of these deficiencies, making the system easier to operate. The ASWN strain measurement system utilizes off-the-shelf sensors, namely strain gauges, with an analog-to-digital converter/amplifier and ZigBee radio chips to keep cost lower. Strain data is captured by the sensor, converted to digital form and delivered to the ZigBee radio chip, which in turn broadcasts the information using wireless protocols to a Personal Data Assistant (PDA) or Laptop/Desktop computers. From here, data is forwarded to remote computers for higher-level analysis and feedback using traditional cellular and satellite communication or the Ethernet infrastructure. This system offers a compact size, lower cost, and temperature insensitivity for critical structural applications, which require immediate monitoring and feedback.

Introducing a sensor to measure budburst and its environmental drivers

PubMed Central

Kleinknecht, George J.; Lintz, Heather E.; Kruger, Anton; Niemeier, James J.; Salino-Hugg, Michael J.; Thomas, Christoph K.; Still, Christopher J.; Kim, Youngil

2015-01-01

Budburst is a key adaptive trait that can help us understand how plants respond to a changing climate from the molecular to landscape scale. Despite this, acquisition of budburst data is constrained by a lack of information at the plant scale on the environmental stimuli associated with the release of bud dormancy. Additionally, to date, little effort has been devoted to phenotyping plants in natural populations due to the challenge of accounting for the effect of environmental variation. Nonetheless, natural selection operates on natural populations, and investigation of adaptive phenotypes in situ is warranted and can validate results from controlled laboratory experiments. To identify genomic effects on individual plant phenotypes in nature, environmental drivers must be concurrently measured, and characterized. Here, we designed and evaluated a sensor to meet these requirements for temperate woody plants. It was designed for use on a tree branch to measure the timing of budburst together with its key environmental drivers; temperature, and photoperiod. Specifically, we evaluated the sensor through independent corroboration with time-lapse photography and a suite of environmental sampling instruments. We also tested whether the presence of the device on a branch influenced the timing of budburst. Our results indicated the following: the temperatures measured by the budburst sensor’s digital thermometer closely approximated the temperatures measured using a thermocouple touching plant tissue; the photoperiod detector measured ambient light with the same accuracy as did time lapse photography; the budburst sensor accurately detected the timing of budburst; and the sensor itself did not influence the budburst timing of Populus clones. Among other potential applications, future use of the sensor may provide plant phenotyping at the landscape level for integration with landscape genomics. PMID:25806035

Development of Gravity Acceleration Measurement Using Simple Harmonic Motion Pendulum Method Based on Digital Technology and Photogate Sensor

NASA Astrophysics Data System (ADS)

Yulkifli; Afandi, Zurian; Yohandri

2018-04-01

Development of gravitation acceleration measurement using simple harmonic motion pendulum method, digital technology and photogate sensor has been done. Digital technology is more practical and optimizes the time of experimentation. The pendulum method is a method of calculating the acceleration of gravity using a solid ball that connected to a rope attached to a stative pole. The pendulum is swung at a small angle resulted a simple harmonic motion. The measurement system consists of a power supply, Photogate sensors, Arduino pro mini and seven segments. The Arduino pro mini receives digital data from the photogate sensor and processes the digital data into the timing data of the pendulum oscillation. The calculation result of the pendulum oscillation time is displayed on seven segments. Based on measured data, the accuracy and precision of the experiment system are 98.76% and 99.81%, respectively. Based on experiment data, the system can be operated in physics experiment especially in determination of the gravity acceleration.

Integration of reconfigurable potentiometric electrochemical sensors into a digital microfluidic platform.

PubMed

Farzbod, Ali; Moon, Hyejin

2018-05-30

This paper presents the demonstration of on-chip fabrication of a potassium-selective sensor array enabled by electrowetting on dielectric digital microfluidics for the first time. This demonstration proves the concept that electrochemical sensors can be seamlessly integrated with sample preparation units in a digital microfluidic platform. More significantly, the successful on-chip fabrication of a sensor array indicates that sensors become reconfigurable and have longer lifetime in a digital microfluidic platform. The on-chip fabrication of ion-selective electrodes includes electroplating Ag followed by forming AgCl layer by chemical oxidation and depositing a thin layer of desired polymer-based ion selective membrane on one of the sensor electrodes. In this study, potassium ionophores work as potassium ion channels and make the membrane selective to potassium ions. This selectiveness results in the voltage difference across the membrane layer, which is correlated with potassium ion concentration. The calibration curve of the fabricated potassium-selective electrode demonstrates the slope of 58 mV/dec for potassium concentration in KCl sample solutions and shows good agreement with the ideal Nernstian response. The proposed sensor platform is an outstanding candidate for a portable home-use for continuous monitoring of ions thanks to its advantages such as easy automation of sample preparation and detection processes, elongated sensor lifetime, minimal membrane and sample consumption, and user-definable/reconfigurable sensor array. Copyright © 2018 Elsevier B.V. All rights reserved.

The use of combined thermal/pressure polyvinylidene fluoride film airflow sensor in polysomnography.

PubMed

Kryger, Meir; Eiken, Todd; Qin, Li

2013-12-01

The technologies recommended by the American Academy of Sleep Medicine (AASM) to monitor airflow in polysomnography (PSG) include the simultaneous monitoring of two physical variables: air temperature (for thermal airflow) and air pressure (for nasal pressure). To comply with airflow monitoring standards in the sleep lab setting thus often requires the patient to wear two sensors under the nose during testing. We hypothesized that a single combined thermal/pressure sensor using polyvinylidene fluoride (PVDF) film responsive to both airflow temperature and pressure would be effective in documenting abnormal breathing events during sleep. Sixty patients undergoing routine PSG testing to rule out obstructive sleep apnea at two different sleep laboratories were asked to wear a third PVDF airflow sensor in addition to the traditional thermal sensor and pressure sensor. Apnea and hypopnea events were scored by the sleep lab technologists using the AASM guidelines (CMS option) using the thermal sensor for apnea and the pressure sensor for hypopnea (scorer 1). The digital PSG data were also forwarded to an outside registered polysomnographic technologist for scoring of respiratory events detected in the PVDF airflow channels (scorer 2). The Pearson correlation coefficient, r, between apnea and hypopnea indices obtained using the AASM sensors and the combined PVDF sensor was almost unity for the four calculated indices: apnea-hypopnea index (0.990), obstructive apnea index (0.992), hypopnea index (0.958), and central apnea index (1.0). The slope of the four relationships was virtually unity and the coefficient of determination (r (2)) was also close to 1. The results of intraclass correlation coefficients (>0.95) and Bland-Altman plots also provide excellent agreement between the combined PVDF sensor and the AASM sensors. The indices used to calculate apnea severity obtained with the combined PVDF thermal and pressure sensor were equivalent to those obtained using AASM-recommended sensors.

Development of CASI (Computer Aided Speckle Interferometry) and LSS (Laser Speckle Sensor) with Application to Material Response under High Strain Rate, High Temperature, Vibration and Fatigue

DTIC Science & Technology

1991-02-10

25. 1"S. revised mcp recerved Apnil 10, 19W, thnnsmte into a VAX- 11� computer. Fringf_ spacing * acceped for puablI Al 126. 1990 This paPetis a...W.Il.Peters, W.F.llanson mtid S.WI.-MN1il, "Detcrintation of dis. placements using an improved (digit al rorrela Ii’’i ii’’ h. . 111 aad Vision Y*omput ing...experiimental mcchaniics", Experiment al Mechianics, Vol.25, No.3, pp 232-.1-1 (1985). 5.~ A.Rosenfeld and A.C.Kak, Digital Pict nre processing, Vol 1

Evaluation of physical properties of different digital intraoral sensors.

PubMed

Al-Rawi, Wisam; Teich, Sorin

2013-09-01

Digital technologies provide clinically acceptable results comparable to traditional films while having other advantages such as the ability to store and manipulate images, immediate evaluation of the image diagnostic quality, possible reduction in patient radiation exposure, and so on. The purpose of this paper is to present the results of the evaluation of the physical design of eight CMOS digital intraoral sensors. Sensors tested included: XDR (Cyber Medical Imaging, Los Angeles, CA, USA), RVG 6100 (Carestream Dental LLC, Atlanta, GA, USA), Platinum (DEXIS LLC., Hatfield, PA, USA), CDR Elite (Schick Technologies, Long Island City, NY, USA), ProSensor (Planmeca, Helsinki, Finland), EVA (ImageWorks, Elmsford, NY, USA), XIOS Plus (Sirona, Bensheim, Germany), and GXS-700 (Gendex Dental Systems, Hatfield, PA, USA). The sensors were evaluated for cable configuration, connectivity interface, presence of back-scattering radiation shield, plate thickness, active sensor area, and comparing the active imaging area to the outside casing and to conventional radiographic films. There were variations among the physical design of different sensors. For most parameters tested, a lack of standardization exists in the industry. The results of this study revealed that these details are not always available through the material provided by the manufacturers and are often not advertised. For all sensor sizes, active imaging area was smaller compared with conventional films. There was no sensor in the group that had the best physical design. Data presented in this paper establishes a benchmark for comparing the physical design of digital intraoral sensors.

Valve health monitoring system utilizing smart instrumentation

NASA Astrophysics Data System (ADS)

Jensen, Scott L.; Drouant, George J.

2006-05-01

The valve monitoring system is a stand alone unit with network capabilities for integration into a higher level health management system. The system is designed for aiding in failure predictions of high-geared ball valves and linearly actuated valves. It performs data tracking and archiving for identifying degraded performance. The data collection types are: cryogenic cycles, total cycles, inlet temperature, outlet temperature, body temperature, torsional strain, linear bonnet strain, preload position, total travel, and total directional changes. Events are recorded and time stamped in accordance with the IRIG B True Time. The monitoring system is designed for use in a Class 1 Division II explosive environment. The basic configuration consists of several instrumentation sensor units and a base station. The sensor units are self contained microprocessor controlled and remotely mountable in three by three by two inches. Each unit is potted in a fire retardant substance without any cavities and limited to low operating power for maintaining safe operation in a hydrogen environment. The units are temperature monitored to safeguard against operation outside temperature limitations. Each contains 902-928 MHz band digital transmitters which meet Federal Communication Commissions requirements and are limited to a 35 foot transmission radius for preserving data security. The base-station controller correlates related data from the sensor units and generates data event logs on a compact flash memory module for database uploading. The entries are also broadcast over an Ethernet network. Nitrogen purged National Electrical Manufactures Association (NEMA) Class 4 Enclosures are used to house the base-station.

Value of Bulk Heat Flux Parameterizations for Ocean SST Prediction

DTIC Science & Technology

2008-01-01

Digital Environmental Model ( GDEM ) climatology (NAVO- CEANO, 2003). The density difference values were chosen so that the layers tend to become...Monthly mean temperature and salinity from the GDEM climatology in August are used to initialize the model. There is a relaxation to monthly mean...retrievals were used. In addition. Special Sensor Microwave Imager (SSM/1) and European Remote Sensing Satellite (ERS) data are used in ERA-40. The SST/Ice

We have "born digital" - now what about "born semantic"?

NASA Astrophysics Data System (ADS)

Leadbetter, Adam; Fredericks, Janet

2014-05-01

The phrase "born-digital" refers to those materials which originate in a digital form. In Earth and Space Sciences, this is now very much the norm for data: analogue to digital converters sit on instrument boards and produce a digital record of the observed environment. While much effort has been put in to creating and curating these digital data, there has been little work on using semantic mark up of data from the point of collection - what we term 'born semantic'. In this presentation we report on two efforts to expand this area: Qartod-to-OGC (Q2O) and SenseOCEAN. These projects have taken a common approach to 'born semantic': create or reuse appropriate controlled vocabularies, published to World Wide Web Commission (W3C) standards use standards from the Open Geospatial Consortium's Sensor Web Enablement (SWE) initiative to describe instrument setup, deployment and/or outputs using terms from those controlled vocabularies embed URLs from the controlled vocabularies within the SWE documents in a "Linked Data" conformant approach Q2O developed best practices examples of SensorML descriptions of Original Equipment Manufacturers' metadata (model characteristics, capabilities, manufacturer contact, etc ...) set-up and deployment SensorML files; and data centre process-lineage using registered vocabularies to describe terms (including input, output, processes, parameters, quality control flags) One Q2O use case, the Martha's Vineyard Coastal Observatory ADCP Waves instance, uses SensorML and registered vocabularies to fully describe the process of computing wave parameters from sensed properties, including quality control tests and associated results. The European Commission Framework Programme 7 project SenseOCEAN draws together world leading marine sensor developers to create a highly integrated multifunction and cost-effective in situ marine biogeochemical sensor system. This project will provide a quantum leap in the ability to measure crucial biogeochemical parameters. Innovations will be combined with state of the art sensor technology to produce a modular sensor system that can be deployed on many platforms. The sensor descriptions are being profiled in SensorML and the controlled vocabularies are being repurposed from those used within the European Commission SeaDataNet project and published on the community standard NERC Vocabulary Server.

MiniDSS: a low-power and high-precision miniaturized digital sun sensor

NASA Astrophysics Data System (ADS)

de Boer, B. M.; Durkut, M.; Laan, E.; Hakkesteegt, H.; Theuwissen, A.; Xie, N.; Leijtens, J. L.; Urquijo, E.; Bruins, P.

2017-11-01

A high-precision and low-power miniaturized digital sun sensor has been developed at TNO. The single-chip sun sensor comprises an application specific integrated circuit (ASIC) on which an active pixel sensor (APS), read-out and processing circuitry as well as communication circuitry are combined. The design was optimized for low recurrent cost. The sensor is albedo insensitive and the prototype combines an accuracy in the order of 0.03° with a mass of just 72 g and a power consumption of only 65 mW.

Design of a simple low cost tethersonde data acquisition system for meteorological measurements

NASA Astrophysics Data System (ADS)

John, Thomas; Garg, S. C.; Maini, H. K.; Chaunal, D. S.; Yadav, V. S.

2005-08-01

A tethersonde instrument for vertical sounding in the lowest height region of the atmosphere designed using commercially available solid state sensors is presented. This instrumentation which was developed for high-resolution measurements of the vertical profiles of atmospheric temperature, humidity, and pressure to study the evolution of radiation fog in winter over Delhi, measures the pressure (800-1100milli-bar), temperature (0-35°C), and relative humidity (0-100% RH) and includes an eight-channel 12bit data acquisition unit and a low-power digital, FM telemetry system operating at 173MHz and uses a PC printer port connection for real-time data logging and operates from a single 9V supply. It is capable of providing data to high resolutions of better than 0.01°C for temperature, 0.07mb for pressure, 0.1% for the relative humidity, and the system has a response time of ˜50s. The sonde can accommodate up to six different sensors according to sounding requirements. The data are serially streamed into the PC and the identification of data from the different sensors is accomplished by using a sync word which is included as a part of the data stream. The sonde has been flown quite successfully a number of times and the flights made thus far have shown excellent performance. The design implementation facilitates easy recalibrations of the individual sensors and their replacement upon failure.

A Technique to Determine the Self-Noise of Seismic Sensors for Performance Screening

NASA Astrophysics Data System (ADS)

Rademacher, H.; Hart, D.; Guralp, C.

2012-04-01

Seismic noise affects the performance of a seismic sensor and is thereby a limiting factor for the detection threshold of monitoring networks. Among the various sources of noise, the intrinsic self-noise of a seismic sensor is most diffcult to determine, because it is mostly masked by natural and anthropogenic ground noise and is also affected by the noise characteristic of the digitizer. Here we present a new technique to determine the self-noise of a seismic system (digitizer + sensors). It is based on a method introduced by Sleeman et al. (2005) to test the noise performance of digitizers. We infer the self-noise of a triplet of identical sensors by comparing coherent waveforms over a wide spectral band across the set-up. We will show first results from a proof-of-concept study done in a vault near Albuquerque, New Mexico. We will show, how various methods of shielding the sensors affect the results of this technique. This method can also be used as a means of quality control during sensor production, because poorly performing sensors can easily be identified.

Design and Implementation of High Precision Temperature Measurement Unit

NASA Astrophysics Data System (ADS)

Zeng, Xianzhen; Yu, Weiyu; Zhang, Zhijian; Liu, Hancheng

2018-03-01

Large-scale neutrino detector requires calibration of photomultiplier tubes (PMT) and electronic system in the detector, performed by plotting the calibration source with a group of designated coordinates in the acrylic sphere. Where the calibration source positioning is based on the principle of ultrasonic ranging, the transmission speed of ultrasonic in liquid scintillator of acrylic sphere is related to temperature. This paper presents a temperature measurement unit based on STM32L031 and single-line bus digital temperature sensor TSic506. The measurement data of the temperature measurement unit can help the ultrasonic ranging to be more accurate. The test results show that the temperature measurement error is within ±0.1°C, which satisfies the requirement of calibration source positioning. Take energy-saving measures, with 3.7V/50mAH lithium battery-powered, the temperature measurement unit can work continuously more than 24 hours.

Comparison of methods of temperature measurement in swine.

PubMed

Hanneman, S K; Jesurum-Urbaitis, J T; Bickel, D R

2004-07-01

The purpose of these experiments was to test the equivalence of pulmonary artery, urinary bladder, tympanic, rectal and femoral artery methods of temperature measurement in healthy and critically ill swine under clinical intensive care unit (ICU) conditions using a prospective, time series design. First, sensors were tested for error and sensitivity to change in temperature with a precision-controlled water bath and a laboratory-certified digital thermometer for temperatures 34-42 degrees C. There was virtually no systematic (bias) or random (precision) error (<0.2 degrees C). The bladder sensor had the slowest response time to change in temperature (105-120 s). Next, testing was done in an experimental porcine ICU in a non-profit research institution with four male, sedated, and mechanically ventilated domestic farm pigs. The in vivo experiments were conducted over periods of 41-168 h with temperatures measured every 1-5 s. The bladder, tympanic and rectal methods had unacceptable bias (>or=0.5 degrees C) and/or precision (>or=0.2 degrees C). Response time varied from 7 s with the femoral artery method to 280 s (4.7 min) with the tympanic method. We concluded that equivalence of the methods was insufficient for them to be used interchangeably in the porcine ICU. Intravascular monitoring of core body temperature produces optimal measurement of porcine temperature under varying conditions of physiological stability.

Design and realization of an automatic weather station at island

NASA Astrophysics Data System (ADS)

Chen, Yong-hua; Li, Si-ren

2011-10-01

In this paper, the design and development of an automatic weather station monitoring is described. The proposed system consists of a set of sensors for measuring meteorological parameters (temperature, wind speed & direction, rain fall, visibility, etc.). To increase the reliability of the system, wind speed & direction are measured redundantly with duplicate sensors. The sensor signals are collected by the data logger CR1000 at several analog and digital inputs. The CR1000 and the sensors form a completely autonomous system which works with the other systems installed in the container. Communication with the master PC is accomplished over the method of Code Division Multiple Access (CDMA) with the Compact Caimore6550P CDMA DTU. The data are finally stored in tables on the CPU as well as on the CF-Card. The weather station was built as an efficient autonomous system which operates with the other systems to provide the required data for a fully automatic measurement system.

Novel Flexible Wearable Sensor Materials and Signal Processing for Vital Sign and Human Activity Monitoring.

PubMed

Servati, Amir; Zou, Liang; Wang, Z Jane; Ko, Frank; Servati, Peyman

2017-07-13

Advances in flexible electronic materials and smart textile, along with broad availability of smart phones, cloud and wireless systems have empowered the wearable technologies for significant impact on future of digital and personalized healthcare as well as consumer electronics. However, challenges related to lack of accuracy, reliability, high power consumption, rigid or bulky form factor and difficulty in interpretation of data have limited their wide-scale application in these potential areas. As an important solution to these challenges, we present latest advances in novel flexible electronic materials and sensors that enable comfortable and conformable body interaction and potential for invisible integration within daily apparel. Advances in novel flexible materials and sensors are described for wearable monitoring of human vital signs including, body temperature, respiratory rate and heart rate, muscle movements and activity. We then present advances in signal processing focusing on motion and noise artifact removal, data mining and aspects of sensor fusion relevant to future clinical applications of wearable technology.

Fluctuating pressures measured beneath a high-temperature, turbulent boundary layer on a flat plate at Mach number of 5

NASA Technical Reports Server (NTRS)

Parrott, Tony L.; Jones, Michael G.; Albertson, Cindy W.

1989-01-01

Fluctuating pressures were measured beneath a Mach 5, turbulent boundary layer on a flat plate with an array of piezoresistive sensors. The data were obtained with a digital signal acquisition system during a test run of 4 seconds. Data sampling rate was such that frequency analysis up to 62.5 kHz could be performed. To assess in situ frequency response of the sensors, a specially designed waveguide calibration system was employed to measure transfer functions of all sensors and related instrumentation. Pressure time histories were approximated well by a Gaussian prohibiting distribution. Pressure spectra were very repeatable over the array span of 76 mm. Total rms pressures ranged from 0.0017 to 0.0046 of the freestream dynamic pressure. Streamwise, space-time correlations exhibited expected decaying behavior of a turbulence generated pressure field. Average convection speed was 0.87 of freestream velocity. The trendless behavior with sensor separation indicated possible systematic errors.

Novel Flexible Wearable Sensor Materials and Signal Processing for Vital Sign and Human Activity Monitoring

PubMed Central

Servati, Amir; Wang, Z. Jane; Ko, Frank; Servati, Peyman

2017-01-01

Advances in flexible electronic materials and smart textile, along with broad availability of smart phones, cloud and wireless systems have empowered the wearable technologies for significant impact on future of digital and personalized healthcare as well as consumer electronics. However, challenges related to lack of accuracy, reliability, high power consumption, rigid or bulky form factor and difficulty in interpretation of data have limited their wide-scale application in these potential areas. As an important solution to these challenges, we present latest advances in novel flexible electronic materials and sensors that enable comfortable and conformable body interaction and potential for invisible integration within daily apparel. Advances in novel flexible materials and sensors are described for wearable monitoring of human vital signs including, body temperature, respiratory rate and heart rate, muscle movements and activity. We then present advances in signal processing focusing on motion and noise artifact removal, data mining and aspects of sensor fusion relevant to future clinical applications of wearable technology. PMID:28703744

Fiber optics for propulsion control systems

NASA Technical Reports Server (NTRS)

Baumbick, R. J.

1985-01-01

In aircraft systems with digital controls, fiberoptics has advantages over wire systems because of its inherent immunity to electromagnetic noise (EMI) and electromagnetic pulses (EMP). It also offers a weight benefit when metallic conductors are replaced by optical fibers. To take full advantage of the benefits of optical waveguides, passive optical sensors are also being developed to eliminate the need for electrical power to the sensor. Fiberoptics may also be used for controlling actuators on engine and airframe. In this application, the optical fibers, connectors, etc. will be subjected to high temperature and vibrations. This paper discussed the use of fiberoptics in aircraft propulsion systems together with the optical sensors and optically controlled actuators being developed to take full advantage of the benefits which fiberoptics offers. The requirements for sensors and actuators in advanced propulsion systems are identified. The benefits of using fiberoptics in place of conventional wire systems are discussed as well as the environmental conditions under which the optical components must operate.

Fiberoptics for propulsion control system

NASA Technical Reports Server (NTRS)

Baumbick, R. J.

1984-01-01

In aircraft systems with digital controls, fiberoptics has advantages over wire systems because of its inherent immunity to electromagnetic noise (EMI) and electromagnetic pulses (EMP). It also offers a weight benefit when metallic conductors are replaced by optical fibers. To take full advantage of the benefits of optical waveguides, passive optical sensors are also being developed to eliminate the need for electrical power to the sensor. Fiberoptics may also be used for controlling actuators on engine and airframe. In this application, the optical fibers, connectors, etc. will be subjected to high temperature and vibrations. This paper discussed the use of fiberoptics in aircraft propulsion systems together with the optical sensors and optically controlled actuators being developed to take full advantage of the benefits which fiberoptics offers. The requirements for sensors and actuators in advanced propulsion systems are identified. The benefits of using fiberoptics in place of conventional wire systems are discussed as well as the environmental conditions under which the optical components must operate.

Energy-efficient digital and wireless IC design for wireless smart sensing

NASA Astrophysics Data System (ADS)

Zhou, Jun; Huang, Xiongchuan; Wang, Chao; Tae-Hyoung Kim, Tony; Lian, Yong

2017-10-01

Wireless smart sensing is now widely used in various applications such as health monitoring and structural monitoring. In conventional wireless sensor nodes, significant power is consumed in wirelessly transmitting the raw data. Smart sensing adds local intelligence to the sensor node and reduces the amount of wireless data transmission via on-node digital signal processing. While the total power consumption is reduced compared to conventional wireless sensing, the power consumption of the digital processing becomes as dominant as wireless data transmission. This paper reviews the state-of-the-art energy-efficient digital and wireless IC design techniques for reducing the power consumption of the wireless smart sensor node to prolong battery life and enable self-powered applications.

Single-shot digital holography by use of the fractional Talbot effect.

PubMed

Martínez-León, Lluís; Araiza-E, María; Javidi, Bahram; Andrés, Pedro; Climent, Vicent; Lancis, Jesús; Tajahuerce, Enrique

2009-07-20

We present a method for recording in-line single-shot digital holograms based on the fractional Talbot effect. In our system, an image sensor records the interference between the light field scattered by the object and a properly codified parallel reference beam. A simple binary two-dimensional periodic grating is used to codify the reference beam generating a periodic three-step phase distribution over the sensor plane by fractional Talbot effect. This provides a method to perform single-shot phase-shifting interferometry at frame rates only limited by the sensor capabilities. Our technique is well adapted for dynamic wavefront sensing applications. Images of the object are digitally reconstructed from the digital hologram. Both computer simulations and experimental results are presented.

Programmable logic controller optical fibre sensor interface module

NASA Astrophysics Data System (ADS)

Allwood, Gary; Wild, Graham; Hinckley, Steven

2011-12-01

Most automated industrial processes use Distributed Control Systems (DCSs) or Programmable Logic Controllers (PLCs) for automated control. PLCs tend to be more common as they have much of the functionality of DCSs, although they are generally cheaper to install and maintain. PLCs in conjunction with a human machine interface form the basis of Supervisory Control And Data Acquisition (SCADA) systems, combined with communication infrastructure and Remote Terminal Units (RTUs). RTU's basically convert different sensor measurands in to digital data that is sent back to the PLC or supervisory system. Optical fibre sensors are becoming more common in industrial processes because of their many advantageous properties. Being small, lightweight, highly sensitive, and immune to electromagnetic interference, means they are an ideal solution for a variety of diverse sensing applications. Here, we have developed a PLC Optical Fibre Sensor Interface Module (OFSIM), in which an optical fibre is connected directly to the OFSIM located next to the PLC. The embedded fibre Bragg grating sensors, are highly sensitive and can detect a number of different measurands such as temperature, pressure and strain without the need for a power supply.

Prototype of a low cost multiparameter probe

NASA Astrophysics Data System (ADS)

Koski, K.; Schwingle, R.; Pullin, M.

2010-12-01

Commercial multi-parameter probes provide accurate, high-resolution temporal data collection of a variety of water quality parameters, but their cost (>5,000) prohibits more than a few sampling locations. We present a design and prototype for a low cost (<250) probe. The cost of the probe is ~5% of commercially available probes, allowing for data collection from ~20 times more sampling points in a field location. The probe is constructed from a single-board microcontroller, a commercially available temperature sensor, a conductivity sensor, and a fabricated optical rhodamine sensor. Using a secure digital (SD) memory card, the probe can record over a month of data at a user specified interval. Construction, calibration, field deployment and data retrieval can be accomplished by a skilled undergraduate. Initial deployment will take place as part of a tracer test in the Valles Caldera National Preserve in northern New Mexico. Future work includes: addition of commercial ion selective electrodes (pH, bromide, nitrate, and others); construction of optically based sensors (chlorophyll, dissolved oxygen, and others); wireless networking between the sensors; and reduction of biofouling.

Interfacing Issues in Microcooling of Optical Detectors in Space Applications

NASA Astrophysics Data System (ADS)

Derking, J. H.; ter Brake, H. J. M.; Linder, M.; Rogalla, H.

2010-04-01

Miniature Joule-Thomson coolers were developed at the University of Twente and are able to cool to 100 K with a typical cooling power of 10 to 20 mW. These coolers have a high potential for space applications in cooling small optical detectors for future earth observation and science missions. Under contract of the European Space Agency, we investigate on-chip detector cooling for the temperature range 70 K-250 K. To identify the detectors that can be cooled by a JT microcooler, a literature survey was performed. Following this survey, we selected a micro digital CMOS image sensor. A conceptual design of this cooler-sensor system is made. Among various techniques, indium soldering and silver paint are chosen for the bonding of the silicon sensor to the glass microcooler. Electrical connections from the sensor to the outside will be realized by structuring them in a thin layer of gold that is sputtered on the outside of the cooler to minimize the radiative heat load. For the electrical connections between the sensor and the structured leads, aluminum or gold bond wires will be used.

A highly sensitive room temperature H2S gas sensor based on SnO2 multi-tube arrays bio-templated from insect bristles.

PubMed

Tian, Junlong; Pan, Feng; Xue, Ruiyang; Zhang, Wang; Fang, Xiaotian; Liu, Qinglei; Wang, Yuhua; Zhang, Zhijian; Zhang, Di

2015-05-07

A tin oxide multi-tube array (SMTA) with a parallel effect was fabricated through a simple and promising method combining chemosynthesis and biomimetic techniques; a biomimetic template was derived from the bristles on the wings of the Alpine Black Swallowtail butterfly (Papilio maackii). SnO2 tubes are hollow and porous structures with micro-pores regularly distributed on the wall. The morphology, the delicate microstructure and the crystal structure of this SMTA were characterized by super resolution digital microscopy, scanning electron microscopy, transmission electron microscopy and X-ray diffraction. The SMTA exhibits a high sensitivity to H2S gas at room temperature. It also exhibits a short response/recovery time, with an average value of 14/30 s at 5 ppm. In particular, heating is not required for the SMTA in the gas sensitivity measurement process. On the basis of these results, SMTA is proposed as a suitable new material for the design and fabrication of room-temperature H2S gas sensors.

Secure smart grid communications and information integration based on digital watermarking in wireless sensor networks

NASA Astrophysics Data System (ADS)

Yan, Xin; Zhang, Ling; Wu, Yang; Luo, Youlong; Zhang, Xiaoxing

2017-02-01

As more and more wireless sensor nodes and networks are employed to acquire and transmit the state information of power equipment in smart grid, we are in urgent need of some viable security solutions to ensure secure smart grid communications. Conventional information security solutions, such as encryption/decryption, digital signature and so forth, are not applicable to wireless sensor networks in smart grid any longer, where bulk messages need to be exchanged continuously. The reason is that these cryptographic solutions will account for a large portion of the extremely limited resources on sensor nodes. In this article, a security solution based on digital watermarking is adopted to achieve the secure communications for wireless sensor networks in smart grid by data and entity authentications at a low cost of operation. Our solution consists of a secure framework of digital watermarking, and two digital watermarking algorithms based on alternating electric current and time window, respectively. Both watermarking algorithms are composed of watermark generation, embedding and detection. The simulation experiments are provided to verify the correctness and practicability of our watermarking algorithms. Additionally, a new cloud-based architecture for the information integration of smart grid is proposed on the basis of our security solutions.

Stability of Fiber Optic Networked Decentralized Distributed Engine Control Under Time Delays

DTIC Science & Technology

2009-08-01

Nomenclature FADEC = Full Authority Digital Engine Control D2FADEC = Decentralized Distributed Full Authority Digital Engine Control DEC...Corporation (IFOS), bm@ifos.com. I American Institute of Aeronautics and Astronautics 2 II. Distributed Engine Control Systems FADEC Based on...of Full Authority Digital Engine Control ( FADEC ) are distributed at the component level. Each sensor/actuator is to be replaced by a smart sensor

Imaging the atmosphere using volcanic infrasound recorded on a dense local sensor network

NASA Astrophysics Data System (ADS)

Marcillo, O. E.; Johnson, J. B.; Johnson, R.

2010-12-01

We deployed a 47-node infrasound sensor network around Kilauea’s Halemaumau Vent to image the atmospheric conditions of the near-surface. This active vent is a persistent radiator of energetic infrasound enabling us to probe atmospheric winds and temperatures. This research builds upon a previous experiment that recorded infrasound on a three-node network, to determine relative phase delay and invert for atmospheric wind. The technique developed for this previous analysis assumed the intrinsic sound speed and was able to track the evolution of the average wind field in a large area (around 10 km2) and was largely insensitive to local meteorological effects, caused by topography and vegetation. The results of this previous experiment showed the potential of this technique for atmospheric studies and called for a following experiment with a denser sensor network over a larger area. During the summer 2010, we returned to Kilauea and deployed a 47-sensor network in three different configurations around Kilauea summit and down the volcano’s flanks. Persistent infrasonic tremor was ‘loud’ with excess pressures up to 10 Pa (when scaled to 1 km) and periods of high acoustic emissions that lasted from hours to days. The instrumentation for this experiment was composed of single-channel RefTek RT125A Texan digitizers and InfraNMT infrasound sensors. The Texan digitizers provide high-resolution 24-bit analog to digital conversion and can operate continuously for approximately five days with two D-cell batteries. The InfraNMT sensor is based on a piezo-electric transducer and was developed at the Infrasound Laboratory at New Mexico Tech. This sensor features low power (< 3 mA at 9 V) and flat response between 0.02 to 50 Hz. Three different network topologies were tested during this two-week experiment. For the first and second topologies, the sensors were deployed along established roads on two almost perpendicular sensor lines centered at the Halema’uma’u crater. The furthest sensors were located at ~24 km and ~10 km from the vent respectively. Numerical analysis indicates that these two configurations will be able to probe the atmospheric conditions up to 2 km above the ground. The third topology featured most of the sensors on the summit crater at similar radial distances (2-4 km) and different azimuths. The data collected with the third topology is expected to provide detailed information of the very-local infrasonic field. Each configuration was on the ground and operational for around 84 hours. This full dataset will provide an opportunity to investigate source phenomenology and/or propagation effects of the infrasonic field. Tomographic studies of the atmosphere are expected to provide meteorological data that will be of value for ash and gas propagation models.

The role of data fusion in predictive maintenance using digital twin

NASA Astrophysics Data System (ADS)

Liu, Zheng; Meyendorf, Norbert; Mrad, Nezih

2018-04-01

Modern aerospace industry is migrating from reactive to proactive and predictive maintenance to increase platform operational availability and efficiency, extend its useful life cycle and reduce its life cycle cost. Multiphysics modeling together with data-driven analytics generate a new paradigm called "Digital Twin." The digital twin is actually a living model of the physical asset or system, which continually adapts to operational changes based on the collected online data and information, and can forecast the future of the corresponding physical counterpart. This paper reviews the overall framework to develop a digital twin coupled with the industrial Internet of Things technology to advance aerospace platforms autonomy. Data fusion techniques particularly play a significant role in the digital twin framework. The flow of information from raw data to high-level decision making is propelled by sensor-to-sensor, sensor-to-model, and model-to-model fusion. This paper further discusses and identifies the role of data fusion in the digital twin framework for aircraft predictive maintenance.

Design details of Intelligent Instruments for PLC-free Cryogenic measurements, control and data acquisition

NASA Astrophysics Data System (ADS)

Antony, Joby; Mathuria, D. S.; Chaudhary, Anup; Datta, T. S.; Maity, T.

2017-02-01

Cryogenic network for linear accelerator operations demand a large number of Cryogenic sensors, associated instruments and other control-instrumentation to measure, monitor and control different cryogenic parameters remotely. Here we describe an alternate approach of six types of newly designed integrated intelligent cryogenic instruments called device-servers which has the complete circuitry for various sensor-front-end analog instrumentation and the common digital back-end http-server built together, to make crateless PLC-free model of controls and data acquisition. These identified instruments each sensor-specific viz. LHe server, LN2 Server, Control output server, Pressure server, Vacuum server and Temperature server are completely deployed over LAN for the cryogenic operations of IUAC linac (Inter University Accelerator Centre linear Accelerator), New Delhi. This indigenous design gives certain salient features like global connectivity, low cost due to crateless model, easy signal processing due to integrated design, less cabling and device-interconnectivity etc.

Advanced one-dimensional optical strain measurement system, phase 4

NASA Technical Reports Server (NTRS)

Lant, Christian T.

1992-01-01

An improved version of the speckle-shift strain measurement system was developed. The system uses a two-dimensional sensor array to maintain speckle correlation in the presence of large off-axis rigid body motions. A digital signal processor (DSP) is used to calculate strains at a rate near the RS-170 camera frame rate. Strain measurements were demonstrated on small diameter wires and fibers used in composite materials research. Accurate values of Young's modulus were measured on tungsten wires, and silicon carbide and sapphire fibers. This optical technique has measured surface strains at specimen temperatures above 750 C and has shown the potential for measurements at much higher temperatures.

Rolling Shutter Effect aberration compensation in Digital Holographic Microscopy

NASA Astrophysics Data System (ADS)

Monaldi, Andrea C.; Romero, Gladis G.; Cabrera, Carlos M.; Blanc, Adriana V.; Alanís, Elvio E.

2016-05-01

Due to the sequential-readout nature of most CMOS sensors, each row of the sensor array is exposed at a different time, resulting in the so-called rolling shutter effect that induces geometric distortion to the image if the video camera or the object moves during image acquisition. Particularly in digital holograms recording, while the sensor captures progressively each row of the hologram, interferometric fringes can oscillate due to external vibrations and/or noises even when the object under study remains motionless. The sensor records each hologram row in different instants of these disturbances. As a final effect, phase information is corrupted, distorting the reconstructed holograms quality. We present a fast and simple method for compensating this effect based on image processing tools. The method is exemplified by holograms of microscopic biological static objects. Results encourage incorporating CMOS sensors over CCD in Digital Holographic Microscopy due to a better resolution and less expensive benefits.

The New Digital Divide For Digital BioMarkers.

PubMed

Torous, John; Rodriguez, Jorge; Powell, Adam

2017-09-01

As smartphone and sensors continue to become more ubiquitous across the world, digital biomarkers have emerged as a scalable and practical tool to explore disease states and advance health. But as the digital divide of access and ownership begins to fade, a new digital divide is emerging. Who are the types of people that own smartphones or smart watches, who are the types of people that download health apps or partake in digital biomarker studies, and who are the types of people that are actually active with digital biomarkers apps and sensors - the people providing the high quality and longitudinal data that this field is being founded upon? Understanding the people behind digital biomarkers, the very people this emerging field aims to help, may actually be the real challenge as well as opportunity for digital biomarkers.

Fiber optical sensing on-board communication satellites

NASA Astrophysics Data System (ADS)

Hurni, A.; Lemke, N. M. K.; Roner, M.; Obermaier, J.; Putzer, P.; Kuhenuri Chami, N.

2017-11-01

Striving constantly to reduce mass, AIT effort and overall cost of the classical point-to-point wired temperature sensor harness on-board telecommunication satellites, OHB System (formerly Kayser-Threde) has introduced the Hybrid Sensor Bus (HSB) system. As a future spacecraft platform element, HSB relies on electrical remote sensor units as well as fiber-optical sensors, both of which can serially be connected in a bus architecture. HSB is a modular measurement system with many applications, also thanks to the opportunities posed by the digital I²C bus. The emphasis, however, is on the introduction of fiber optics and especially fiber-Bragg grating (FBG) temperature sensors as disruptive innovation for the company's satellite platforms. The light weight FBG sensors are directly inscribed in mechanically robust and radiation tolerant fibers, reducing the need for optical fiber connectors and splices to a minimum. Wherever an FBG sensor shall be used, the fiber is glued together with a corresponding temperature transducer to the satellites structure or to a subsystem. The transducer is necessary to provide decoupling of mechanical stress, but simultaneously ensure a high thermal conductivity. HSB has been developed in the frame of an ESA-ARTES program with European and German co-funding and will be verified as flight demonstrator on-board the German Heinrich Hertz satellite (H2Sat). In this paper the Engineering Model development of HSB is presented and a Fiber-optical Sensor Multiplexer for a more flexible sensor bus architecture is introduced. The HSB system aims at telecommunication satellite platforms with an operational life time beyond 15 years in geostationary orbit. It claims a high compatibility in terms of performance and interfaces with existing platforms while it was designed with future applications with increased radiation exposure already in mind. In its basic configuration HSB consists of four modules which are the Power Supply Unit, the HSB Controller Module, the Interrogator Controller Module and the Analog Front-End for the fiber-optical interrogation. The Interrogator Controller Module handles both, the electrical and fiber-optical sensor network. For the latter it is to be completed by the Analog Front-End. On this front-end, a tunable laser diode is implemented for the scanning of the FBG sensors. The reflected spectra are measured on multiple fiber channels and are then evaluated by use of a peak detection algorithm in order to obtain a precise temperature measurement. The precise operation of the photonic system on long terms can be guaranteed thanks to an inorbit calibration concept.

Bio-inspired multi-mode optic flow sensors for micro air vehicles

NASA Astrophysics Data System (ADS)

Park, Seokjun; Choi, Jaehyuk; Cho, Jihyun; Yoon, Euisik

2013-06-01

Monitoring wide-field surrounding information is essential for vision-based autonomous navigation in micro-air-vehicles (MAV). Our image-cube (iCube) module, which consists of multiple sensors that are facing different angles in 3-D space, can be applied to the wide-field of view optic flows estimation (μ-Compound eyes) and to attitude control (μ- Ocelli) in the Micro Autonomous Systems and Technology (MAST) platforms. In this paper, we report an analog/digital (A/D) mixed-mode optic-flow sensor, which generates both optic flows and normal images in different modes for μ- Compound eyes and μ-Ocelli applications. The sensor employs a time-stamp based optic flow algorithm which is modified from the conventional EMD (Elementary Motion Detector) algorithm to give an optimum partitioning of hardware blocks in analog and digital domains as well as adequate allocation of pixel-level, column-parallel, and chip-level signal processing. Temporal filtering, which may require huge hardware resources if implemented in digital domain, is remained in a pixel-level analog processing unit. The rest of the blocks, including feature detection and timestamp latching, are implemented using digital circuits in a column-parallel processing unit. Finally, time-stamp information is decoded into velocity from look-up tables, multiplications, and simple subtraction circuits in a chip-level processing unit, thus significantly reducing core digital processing power consumption. In the normal image mode, the sensor generates 8-b digital images using single slope ADCs in the column unit. In the optic flow mode, the sensor estimates 8-b 1-D optic flows from the integrated mixed-mode algorithm core and 2-D optic flows with an external timestamp processing, respectively.

Valve Health Monitoring System Utilizing Smart Instrumentation

NASA Technical Reports Server (NTRS)

Jensen, Scott L.; Drouant, George J.

2006-01-01

The valve monitoring system is a stand alone unit with network capabilities for integration into a higher level health management system. The system is designed for aiding in failure predictions of high-geared ball valves and linearly actuated valves. It performs data tracking and archiving for identifying degraded performance. The data collection types are cryogenic cycles, total cycles, inlet temperature, body temperature torsional strain, linear bonnet strain, preload position, total travel and total directional changes. Events are recorded and time stamped in accordance with the IRIG B True Time. The monitoring system is designed for use in a Class 1 Division II explosive environment. The basic configuration consists of several instrumentation sensor units and a base station. The sensor units are self contained microprocessor controlled and remotely mountable in three by three by two inches. Each unit is potted in a fire retardant substance without any cavities and limited to low operating power for maintaining safe operation in a hydrogen environment. The units are temperature monitored to safeguard against operation outside temperature limitations. Each contains 902-928 MHz band digital transmitters which meet Federal Communication Commission's requirements and are limited to a 35 foot transmission radius for preserving data security. The base-station controller correlates data from the sensor units and generates data event logs on a compact flash memory module for database uploading. The entries are also broadcast over an Ethernet network. Nitrogen purged National Electrical Manufactures Association (NEMA) Class 4 enclosures are used to house the base-station

High speed and high resolution interrogation of a fiber Bragg grating sensor based on microwave photonic filtering and chirped microwave pulse compression.

PubMed

Xu, Ou; Zhang, Jiejun; Yao, Jianping

2016-11-01

High speed and high resolution interrogation of a fiber Bragg grating (FBG) sensor based on microwave photonic filtering and chirped microwave pulse compression is proposed and experimentally demonstrated. In the proposed sensor, a broadband linearly chirped microwave waveform (LCMW) is applied to a single-passband microwave photonic filter (MPF) which is implemented based on phase modulation and phase modulation to intensity modulation conversion using a phase modulator (PM) and a phase-shifted FBG (PS-FBG). Since the center frequency of the MPF is a function of the central wavelength of the PS-FBG, when the PS-FBG experiences a strain or temperature change, the wavelength is shifted, which leads to the change in the center frequency of the MPF. At the output of the MPF, a filtered chirped waveform with the center frequency corresponding to the applied strain or temperature is obtained. By compressing the filtered LCMW in a digital signal processor, the resolution is improved. The proposed interrogation technique is experimentally demonstrated. The experimental results show that interrogation sensitivity and resolution as high as 1.25 ns/με and 0.8 με are achieved.

A new physical unclonable function architecture

NASA Astrophysics Data System (ADS)

Chuang, Bai; Xuecheng, Zou; Kui, Dai

2015-03-01

This paper describes a new silicon physical unclonable function (PUF) architecture that can be fabricated on a standard CMOS process. Our proposed architecture is built using process sensors, difference amplifier, comparator, voting mechanism and diffusion algorithm circuit. Multiple identical process sensors are fabricated on the same chip. Due to manufacturing process variations, each sensor produces slightly different physical characteristic values that can be compared in order to create a digital identification for the chip. The diffusion algorithm circuit ensures further that the PUF based on the proposed architecture is able to effectively identify a population of ICs. We also improve the stability of PUF design with respect to temporary environmental variations like temperature and supply voltage with the introduction of difference amplifier and voting mechanism. The PUF built on the proposed architecture is fabricated in 0.18 μm CMOS technology. Experimental results show that the PUF has a good output statistical characteristic of uniform distribution and a high stability of 98.1% with respect to temperature variation from -40 to 100 °C, and supply voltage variation from 1.7 to 1.9 V. Project supported by the National Natural Science Foundation of China (No. 61376031).

Frequency multiplexed superconducting quantum interference device readout of large bolometer arrays for cosmic microwave background measurements.

PubMed

Dobbs, M A; Lueker, M; Aird, K A; Bender, A N; Benson, B A; Bleem, L E; Carlstrom, J E; Chang, C L; Cho, H-M; Clarke, J; Crawford, T M; Crites, A T; Flanigan, D I; de Haan, T; George, E M; Halverson, N W; Holzapfel, W L; Hrubes, J D; Johnson, B R; Joseph, J; Keisler, R; Kennedy, J; Kermish, Z; Lanting, T M; Lee, A T; Leitch, E M; Luong-Van, D; McMahon, J J; Mehl, J; Meyer, S S; Montroy, T E; Padin, S; Plagge, T; Pryke, C; Richards, P L; Ruhl, J E; Schaffer, K K; Schwan, D; Shirokoff, E; Spieler, H G; Staniszewski, Z; Stark, A A; Vanderlinde, K; Vieira, J D; Vu, C; Westbrook, B; Williamson, R

2012-07-01

A technological milestone for experiments employing transition edge sensor bolometers operating at sub-Kelvin temperature is the deployment of detector arrays with 100s-1000s of bolometers. One key technology for such arrays is readout multiplexing: the ability to read out many sensors simultaneously on the same set of wires. This paper describes a frequency-domain multiplexed readout system which has been developed for and deployed on the APEX-SZ and South Pole Telescope millimeter wavelength receivers. In this system, the detector array is divided into modules of seven detectors, and each bolometer within the module is biased with a unique ∼MHz sinusoidal carrier such that the individual bolometer signals are well separated in frequency space. The currents from all bolometers in a module are summed together and pre-amplified with superconducting quantum interference devices operating at 4 K. Room temperature electronics demodulate the carriers to recover the bolometer signals, which are digitized separately and stored to disk. This readout system contributes little noise relative to the detectors themselves, is remarkably insensitive to unwanted microphonic excitations, and provides a technology pathway to multiplexing larger numbers of sensors.

Field Programmable Gate Array (FPGA) Respiratory Monitoring System Using a Flow Microsensor and an Accelerometer

NASA Astrophysics Data System (ADS)

Mellal, Idir; Laghrouche, Mourad; Bui, Hung Tien

2017-04-01

This paper describes a non-invasive system for respiratory monitoring using a Micro Electro Mechanical Systems (MEMS) flow sensor and an IMU (Inertial Measurement Unit) accelerometer. The designed system is intended to be wearable and used in a hospital or at home to assist people with respiratory disorders. To ensure the accuracy of our system, we proposed a calibration method based on ANN (Artificial Neural Network) to compensate the temperature drift of the silicon flow sensor. The sigmoid activation functions used in the ANN model were computed with the CORDIC (COordinate Rotation DIgital Computer) algorithm. This algorithm was also used to estimate the tilt angle in body position. The design was implemented on reconfigurable platform FPGA.

A Multi-Sensor Aerogeophysical Study of Afghanistan

DTIC Science & Technology

2007-01-01

magnetometer coupled with an Applied Physics 539 3-axis fluxgate mag- netometer for compensation of the aircraft field; • an Applanix DSS 301 digital...survey. DATA COlleCTION AND PROCeSSINg Photogrammetry More than 65,000 high-resolution photogram- metric images were collected using an Applanix Digital...HSI L-Band Polarimetric Imaging Radar KGPS Dual Gravity Meters Common Sensor Bomb-bay Pallet Applanix DSS Camera Sensor Suite • Magnetometer • Gravity

Investigation of Various Surface Acoustic Wave Design Configurations for Improved Sensitivity

NASA Astrophysics Data System (ADS)

Manohar, Greeshma

Surface acoustic wave sensors have been a focus of active research for many years. Its ability to respond for surface perturbation is a basic principle for its sensing capability. Sensitivity to surface perturbation changes with every inter-digital transducer (IDT) design parameters, substrate selection, metallization choice and technique, delay line length and working environment. In this thesis, surface acoustic wave (SAW) sensors are designed and characterized to improve sensitivity and reduce loss. To quantify the improvements with a specific design configuration, the sensors are employed to measure temperature. Four SAW sensors design configurations, namely bi-directional, split electrode, single phase unidirectional transducer (SPUDT) and metal grating on delay line (shear transvers wave sensors) are designed and then fabricated in Nanotechnology Research and Education Center (NREC) facility using traditional MEMS fabrication processes Additionally, sensors are then coated with guiding layer SU8-2035 of 40µm using spin coating and SiO 2 of 6µm using plasma enhanced chemical vapor deposition (PECVD) process. Sensors are later diced and tested for every 5°C increment using network analyzer for temperature ranging from 30°C±0.5°C to 80°C±0.5°C. Data acquired from network analyzer is analyzed using plot of logarithmic magnitude, phase and frequency shift. Furthermore, to investigate the effect of metallization technique on the sensor performance, sensors are also fabricated on substrates that were metallized at a commercial MEMS foundry. All in-house and outside sputtered sensor configurations are compared to investigate quality of sputtered metal on wafer. One with better quality sputtered metal is chosen for further study. Later sensors coated with SU8 and SiO2 as guiding layer are compared to investigate effect of each waveguide on sensors and determine which waveguide offers better performance. The results showed that company sputtered sensors have higher sensitivity compared to in-house sputtered wafers. Furthermore after comparing SU8 and SiO2 coated sensors in the same instrumental and environmental condition, it was observed that SU8 coated di-directional and single phase unidirectional transducer (SPUDT) sensors showed best response.

Video Guidance Sensor System With Integrated Rangefinding

NASA Technical Reports Server (NTRS)

Book, Michael L. (Inventor); Bryan, Thomas C. (Inventor); Howard, Richard T. (Inventor); Roe, Fred Davis, Jr. (Inventor); Bell, Joseph L. (Inventor)

2006-01-01

A video guidance sensor system for use, p.g., in automated docking of a chase vehicle with a target vehicle. The system includes an integrated rangefinder sub-system that uses time of flight measurements to measure range. The rangefinder sub-system includes a pair of matched photodetectors for respectively detecting an output laser beam and return laser beam, a buffer memory for storing the photodetector outputs, and a digitizer connected to the buffer memory and including dual amplifiers and analog-to-digital converters. A digital signal processor processes the digitized output to produce a range measurement.

The PennBMBI: Design of a General Purpose Wireless Brain-Machine-Brain Interface System.

PubMed

Liu, Xilin; Zhang, Milin; Subei, Basheer; Richardson, Andrew G; Lucas, Timothy H; Van der Spiegel, Jan

2015-04-01

In this paper, a general purpose wireless Brain-Machine-Brain Interface (BMBI) system is presented. The system integrates four battery-powered wireless devices for the implementation of a closed-loop sensorimotor neural interface, including a neural signal analyzer, a neural stimulator, a body-area sensor node and a graphic user interface implemented on the PC end. The neural signal analyzer features a four channel analog front-end with configurable bandpass filter, gain stage, digitization resolution, and sampling rate. The target frequency band is configurable from EEG to single unit activity. A noise floor of 4.69 μVrms is achieved over a bandwidth from 0.05 Hz to 6 kHz. Digital filtering, neural feature extraction, spike detection, sensing-stimulating modulation, and compressed sensing measurement are realized in a central processing unit integrated in the analyzer. A flash memory card is also integrated in the analyzer. A 2-channel neural stimulator with a compliance voltage up to ± 12 V is included. The stimulator is capable of delivering unipolar or bipolar, charge-balanced current pulses with programmable pulse shape, amplitude, width, pulse train frequency and latency. A multi-functional sensor node, including an accelerometer, a temperature sensor, a flexiforce sensor and a general sensor extension port has been designed. A computer interface is designed to monitor, control and configure all aforementioned devices via a wireless link, according to a custom designed communication protocol. Wireless closed-loop operation between the sensory devices, neural stimulator, and neural signal analyzer can be configured. The proposed system was designed to link two sites in the brain, bridging the brain and external hardware, as well as creating new sensory and motor pathways for clinical practice. Bench test and in vivo experiments are performed to verify the functions and performances of the system.

CMOS image sensor with organic photoconductive layer having narrow absorption band and proposal of stack type solid-state image sensors

NASA Astrophysics Data System (ADS)

Takada, Shunji; Ihama, Mikio; Inuiya, Masafumi

2006-02-01

Digital still cameras overtook film cameras in Japanese market in 2000 in terms of sales volume owing to their versatile functions. However, the image-capturing capabilities such as sensitivity and latitude of color films are still superior to those of digital image sensors. In this paper, we attribute the cause for the high performance of color films to their multi-layered structure, and propose the solid-state image sensors with stacked organic photoconductive layers having narrow absorption bands on CMOS read-out circuits.

Quality Evaluation of Agricultural Distillates Using an Electronic Nose

PubMed Central

Dymerski, Tomasz; Gębicki, Jacek; Wardencki, Waldemar; Namieśnik, Jacek

2013-01-01

The paper presents the application of an electronic nose instrument to fast evaluation of agricultural distillates differing in quality. The investigations were carried out using a prototype of electronic nose equipped with a set of six semiconductor sensors by FIGARO Co., an electronic circuit converting signal into digital form and a set of thermostats able to provide gradient temperature characteristics to a gas mixture. A volatile fraction of the agricultural distillate samples differing in quality was obtained by barbotage. Interpretation of the results involved three data analysis techniques: principal component analysis, single-linkage cluster analysis and cluster analysis with spheres method. The investigations prove the usefulness of the presented technique in the quality control of agricultural distillates. Optimum measurements conditions were also defined, including volumetric flow rate of carrier gas (15 L/h), thermostat temperature during the barbotage process (15 °C) and time of sensor signal acquisition from the onset of the barbotage process (60 s). PMID:24287525

Infrasound Sensor Calibration and Response

DTIC Science & Technology

2012-09-01

infrasound calibration chamber. Under separate funding a number of upgrades were made to the chamber. These include a Geotech Smart24 digitizer and...of upgrades were made to the chamber. These include a Geotech Smart24 digitizer and workstation, an LVDT sensor for piston phone phase measurement, a...20 samples per second on a GeoTech Instruments DL 24 digitizer. Fifty cycles of data were fit with the Matlab function NLINFIT that gave the peak

Applied digital signal processing systems for vortex flowmeter with digital signal processing.

PubMed

Xu, Ke-Jun; Zhu, Zhi-Hai; Zhou, Yang; Wang, Xiao-Fen; Liu, San-Shan; Huang, Yun-Zhi; Chen, Zhi-Yuan

2009-02-01

The spectral analysis is combined with digital filter to process the vortex sensor signal for reducing the effect of disturbance at low frequency from pipe vibrations and increasing the turndown ratio. Using digital signal processing chip, two kinds of digital signal processing systems are developed to implement these algorithms. One is an integrative system, and the other is a separated system. A limiting amplifier is designed in the input analog condition circuit to adapt large amplitude variation of sensor signal. Some technique measures are taken to improve the accuracy of the output pulse, speed up the response time of the meter, and reduce the fluctuation of the output signal. The experimental results demonstrate the validity of the digital signal processing systems.

RFQ (radio-frequency quadrupole) accelerator tuning system

DOEpatents

Bolie, V.W.

1988-04-12

A cooling system is provided for maintaining a preselected operating temperature in a device, which may be an RFQ accelerator, having a variable heat removal requirement, by circulating a cooling fluid through a cooling system remote from the device. Internal sensors in the device enable an estimated error signal to be generated from parameters which are indicative of the heat removal requirement from the device. Sensors are provided at predetermined locations in the cooling system for outputting operational temperature signals. Analog and digital computers define a control signal functionally related to the temperature signals and the estimated error signal, where the control signal is defined effective to return the device to the preselected operating temperature in a stable manner. The cooling system includes a first heat sink responsive to a first portion of the control signal to remove heat from a major portion of the circulating fluid. A second heat sink is responsive to a second portion of the control to remove heat from a minor portion of the circulating fluid. The cooled major and minor portions of the circulating fluid are mixed in responsive to a mixing portion of the control signal, which is effective to proportion the major and minor portions of the circulating fluid to establish a mixed fluid temperature which is effective to define the preselected operating temperature for the remote device. 3 figs., 2 tabs.

Median filters as a tool to determine dark noise thresholds in high resolution smartphone image sensors for scientific imaging

NASA Astrophysics Data System (ADS)

Igoe, Damien P.; Parisi, Alfio V.; Amar, Abdurazaq; Rummenie, Katherine J.

2018-01-01

An evaluation of the use of median filters in the reduction of dark noise in smartphone high resolution image sensors is presented. The Sony Xperia Z1 employed has a maximum image sensor resolution of 20.7 Mpixels, with each pixel having a side length of just over 1 μm. Due to the large number of photosites, this provides an image sensor with very high sensitivity but also makes them prone to noise effects such as hot-pixels. Similar to earlier research with older models of smartphone, no appreciable temperature effects were observed in the overall average pixel values for images taken in ambient temperatures between 5 °C and 25 °C. In this research, hot-pixels are defined as pixels with intensities above a specific threshold. The threshold is determined using the distribution of pixel values of a set of images with uniform statistical properties associated with the application of median-filters of increasing size. An image with uniform statistics was employed as a training set from 124 dark images, and the threshold was determined to be 9 digital numbers (DN). The threshold remained constant for multiple resolutions and did not appreciably change even after a year of extensive field use and exposure to solar ultraviolet radiation. Although the temperature effects' uniformity masked an increase in hot-pixel occurrences, the total number of occurrences represented less than 0.1% of the total image. Hot-pixels were removed by applying a median filter, with an optimum filter size of 7 × 7; similar trends were observed for four additional smartphone image sensors used for validation. Hot-pixels were also reduced by decreasing image resolution. The method outlined in this research provides a methodology to characterise the dark noise behavior of high resolution image sensors for use in scientific investigations, especially as pixel sizes decrease.

3rd-generation MW/LWIR sensor engine for advanced tactical systems

NASA Astrophysics Data System (ADS)

King, Donald F.; Graham, Jason S.; Kennedy, Adam M.; Mullins, Richard N.; McQuitty, Jeffrey C.; Radford, William A.; Kostrzewa, Thomas J.; Patten, Elizabeth A.; McEwan, Thomas F.; Vodicka, James G.; Wootan, John J.

2008-04-01

Raytheon has developed a 3rd-Generation FLIR Sensor Engine (3GFSE) for advanced U.S. Army systems. The sensor engine is based around a compact, productized detector-dewar assembly incorporating a 640 x 480 staring dual-band (MW/LWIR) focal plane array (FPA) and a dual-aperture coldshield mechanism. The capability to switch the coldshield aperture and operate at either of two widely-varying f/#s will enable future multi-mode tactical systems to more fully exploit the many operational advantages offered by dual-band FPAs. RVS has previously demonstrated high-performance dual-band MW/LWIR FPAs in 640 x 480 and 1280 x 720 formats with 20 μm pitch. The 3GFSE includes compact electronics that operate the dual-band FPA and variable-aperture mechanism, and perform 14-bit analog-to-digital conversion of the FPA output video. Digital signal processing electronics perform "fixed" two-point non-uniformity correction (NUC) of the video from both bands and optional dynamic scene-based NUC; advanced enhancement processing of the output video is also supported. The dewar-electronics assembly measures approximately 4.75 x 2.25 x 1.75 inches. A compact, high-performance linear cooler and cooler electronics module provide the necessary FPA cooling over a military environmental temperature range. 3GFSE units are currently being assembled and integrated at RVS, with the first units planned for delivery to the US Army.

N channel JFET based digital logic gate structure

NASA Technical Reports Server (NTRS)

Krasowski, Michael J. (Inventor)

2010-01-01

A circuit topography is presented which is used to create usable digital logic gates using N (negatively doped) channel Junction Field Effect Transistors (JFETs) and load resistors, level shifting resistors, and supply rails whose values are based on the direct current (DC) parametric distributions of those JFETs. This method has direct application to the current state of the art in high temperature, for example 300.degree. C. to 500.degree. C. and higher, silicon carbide (SiC) device production. The ability to produce inverting and combinatorial logic enables the production of pulse and edge triggered latches. This scale of logic synthesis would bring digital logic and state machine capabilities to devices operating in extremely hot environments, such as the surface of Venus, near hydrothermal vents, within nuclear reactors (SiC is inherently radiation hardened), and within internal combustion engines. The basic logic gate can be configured as a driver for oscillator circuits allowing for time bases and simple digitizers for resistive or reactive sensors. The basic structure of this innovation, the inverter, can be reconfigured into various analog circuit topographies through the use of feedback structures.

Muscle Strength Endurance Testing Development Based Photo Transistor with Motion Sensor Ultrasonic

NASA Astrophysics Data System (ADS)

Rusdiana, A.

2017-03-01

The endurance of upper-body muscles is one of the most important physical fitness components. As technology develops, the process of test and assessment is now getting digital; for instance, there are a sensor stuck to the shoe (Foot Pod, Polar, and Sunto), Global Positioning System (GPS) and Differential Global Positioning System (DGPS), radar, photo finish, kinematic analysis, and photocells. Those devices aim to analyze the performances and fitness of athletes particularly the endurance of arm, chest, and shoulder muscles. In relation to that, this study attempt to create a software and a hardware for pull-ups through phototransistor with ultrasonic motion sensor. Components needed to develop this device consist of microcontroller MCS-51, photo transistor, light emitting diode, buzzer, ultrasonic sensor, and infrared sensor. The infrared sensor is put under the buffer while the ultrasonic sensor is stuck on the upper pole. The components are integrated with an LED or a laptop made using Visual Basic 12 software. The results show that pull-ups test using digital device (mean; 9.4 rep) is lower than using manual calculation (mean; 11.3 rep). This is due to the fact that digital test requires the test-takers to do pull-ups perfectly.

Field Micrometeorological Measurements, Process-Level Studies and Modeling of Methane and Carbon Dioxide Fluxes in a Boreal Wetland Ecosystem

NASA Technical Reports Server (NTRS)

Verma, S. B.; Arkebauer, T. J.; Ullman, F. G.; Valentine, D. W.; Parton, W. J.; Schimel, D. S.

1998-01-01

The main instrumentation platform consisted of eddy correlation sensors mounted on a scaffold tower at a height of 4.2 m above the peat surface. The sensors were attached to a boom assembly which could be rotated into the prevailing winds. The boom assembly was mounted on a movable sled which, when extended, allowed sensors to be up to 2 m away from the scaffolding structure to minimize flow distortion. When retracted, the sensors could easily be installed, serviced or rotated. An electronic level with linear actuators allowed the sensors to be remotely levelled once the sled was extended. Two instrument arrays were installed. A primary (fast-response) array consisted of a three-dimensional sonic anemometer, a methane sensor (tunable diode laser spectrometer), a carbon dioxide/water vapor sensor, a fine wire thermocouple and a backup one-dimensional sonic anemometer. The secondary array consisted of a one-dimensional sonic anemometer, a fine wire thermocouple and a Krypton hygrometer. Descriptions of these sensors may be found in other reports (e.g., Verma; Suyker and Verma). Slow-response sensors provided supporting measurements including mean air temperature and humidity, mean horizontal windspeed and direction, incoming and reflected solar radiation, net radiation, incoming and reflected photosynthetically active radiation (PAR), soil heat flux, peat temperature, water-table elevation and precipitation. A data acquisition system (consisting of an IBM compatible microcomputer, amplifiers and a 16 bit analog-to-digital converter), housed in a small trailer, was used to record the fast response signals. These signals were low-pass filtered (using 8-pole Butterworth active filters with a 12.5 Hz cutoff frequency) and sampled at 25 Hz. Slow-response signals were sampled every 5 s using a network of CR21X (Campbell Scientific, Inc., Logan Utah) data loggers installed in the fen. All signals were averaged over 30-minute periods (runs).

A Mobile Sensor Network to Map CO2 in Urban Environments

NASA Astrophysics Data System (ADS)

Lee, J.; Christen, A.; Nesic, Z.; Ketler, R.

2014-12-01

Globally, an estimated 80% of all fuel-based CO2 emissions into the atmosphere are attributable to cities, but there is still a lack of tools to map, visualize and monitor emissions to the scales at which emissions reduction strategies can be implemented - the local and urban scale. Mobile CO2 sensors, such as those attached to taxis and other existing mobile platforms, may be a promising way to observe and map CO2 mixing ratios across heterogenous urban environments with a limited number of sensors. Emerging modular open source technologies, and inexpensive compact sensor components not only enable rapid prototyping and replication, but also are allowing for the miniaturization and mobilization of traditionally fixed sensor networks. We aim to optimize the methods and technologies for monitoring CO2 in cities using a network of CO2 sensors deployable on vehicles and bikes. Our sensor technology is contained in a compact weather-proof case (35.8cm x 27.8cm x 11.8cm), powered independently by battery or by car, and includes the Li-Cor Li-820 infrared gas analyzer (Licor Inc, lincoln, NB, USA), Arduino Mega microcontroller (Arduino CC, Italy) and Adafruit GPS (Adafruit Technologies, NY, USA), and digital air temperature thermometer which measure CO2 mixing ratios (ppm), geolocation and speed, pressure and temperature, respectively at 1-second intervals. With the deployment of our sensor technology, we will determine if such a semi-autonomous mobile approach to monitoring CO2 in cities can determine excess urban CO2 mixing ratios (i.e. the 'urban CO2 dome') when compared to values measured at a fixed, remote background site. We present results from a pilot study in Vancouver, BC, where the a network of our new sensors was deployed both in fixed network and in a mobile campaign and examine the spatial biases of the two methods.

The IRIS Data Management Center: An international "network of networks", providing open, automated access to geographically distributed sensors of geophysical and environmental data.

NASA Astrophysics Data System (ADS)

Benson, R. B.; Ahern, T. K.; Trabant, C.

2006-12-01

The IRIS Data Management System has long supported international collaboration for seismology by both deploying a global network of seismometers and creating and maintaining an open and accessible archive in Seattle, WA, known as the Data Management Center (DMC). With sensors distributed on a global scale spanning more than 30 years of digital data, the DMC provides a rich repository of observations across broad time and space domains. Primary seismological data types include strong motion and broadband seismometers, conventional and superconducting gravimeters, tilt and creep meters, GPS measurements, along with other similar sensors that record accurate and calibrated ground motion. What may not be as well understood is the volume of environmental data that accompanies typical seismological data these days. This poster will review the types of time-series data that are currently being collected, how they are collected, and made freely available for download at the IRIS DMC. Environmental sensor data that is often co-located with geophysical data sensors include temperature, barometric pressure, wind direction and speed, humidity, insolation, rain gauge, and sometimes hydrological data like water current, level, temperature and depth. As the primary archival institution of the International Federation of Digital Seismograph Networks (FDSN), the IRIS DMC collects approximately 13,600 channels of real-time data from 69 different networks, from close to 1600 individual stations, currently averaging 10Tb per year in total. A major contribution to the IRIS archive currently is the EarthScope project data, a ten-year science undertaking that is collecting data from a high-resolution, multi-variate sensor network. Data types include magnetotelluric, high-sample rate seismics from a borehole drilled into the San Andreas fault (SAFOD) and various types of strain data from the Plate Boundary Observatory (PBO). In addition to the DMC, data centers located in other countries are networked seamlessly, and are providing access for researchers to these data from national networks around the world utilizing the IRIS developed Data Handling Interface (DHI) system. This poster will highlight some of the DHI enabled clients that allow geophysical information to be directly transferred to the clients. This ability allows one to construct a virtual network of data centers providing the illusion of a single virtual observatory. Furthermore, some of the features that will be shown include direct connections to MATLAB and the ability to access globally distributed sensor data in real time. We encourage discussion and participation from network operators who would like to leverage existing technology, as well as enabling collaboration.

Applications of Action Cam Sensors in the Archaeological Yard

NASA Astrophysics Data System (ADS)

Pepe, M.; Ackermann, S.; Fregonese, L.; Fassi, F.; Adami, A.

2018-05-01

In recent years, special digital cameras called "action camera" or "action cam", have become popular due to their low price, smallness, lightness, strength and capacity to make videos and photos even in extreme environment surrounding condition. Indeed, these particular cameras have been designed mainly to capture sport actions and work even in case of dirt, bumps, or underwater and at different external temperatures. High resolution of Digital single-lens reflex (DSLR) cameras are usually preferred to be employed in photogrammetric field. Indeed, beyond the sensor resolution, the combination of such cameras with fixed lens with low distortion are preferred to perform accurate 3D measurements; at the contrary, action cameras have small and wide-angle lens, with a lower performance in terms of sensor resolution, lens quality and distortions. However, by considering the characteristics of the action cameras to acquire under conditions that may result difficult for standard DSLR cameras and because of their lower price, these could be taken into consideration as a possible and interesting approach during archaeological excavation activities to document the state of the places. In this paper, the influence of lens radial distortion and chromatic aberration on this type of cameras in self-calibration mode and an evaluation of their application in the field of Cultural Heritage will be investigated and discussed. Using a suitable technique, it has been possible to improve the accuracy of the 3D model obtained by action cam images. Case studies show the quality and the utility of the use of this type of sensor in the survey of archaeological artefacts.

Digital mammography, cancer screening: Factors important for image compression

NASA Technical Reports Server (NTRS)

Clarke, Laurence P.; Blaine, G. James; Doi, Kunio; Yaffe, Martin J.; Shtern, Faina; Brown, G. Stephen; Winfield, Daniel L.; Kallergi, Maria

1993-01-01

The use of digital mammography for breast cancer screening poses several novel problems such as development of digital sensors, computer assisted diagnosis (CAD) methods for image noise suppression, enhancement, and pattern recognition, compression algorithms for image storage, transmission, and remote diagnosis. X-ray digital mammography using novel direct digital detection schemes or film digitizers results in large data sets and, therefore, image compression methods will play a significant role in the image processing and analysis by CAD techniques. In view of the extensive compression required, the relative merit of 'virtually lossless' versus lossy methods should be determined. A brief overview is presented here of the developments of digital sensors, CAD, and compression methods currently proposed and tested for mammography. The objective of the NCI/NASA Working Group on Digital Mammography is to stimulate the interest of the image processing and compression scientific community for this medical application and identify possible dual use technologies within the NASA centers.

Pattern-Directed Ordering of Spin-Dewetted Liquid Crystal Micro- or Nanodroplets as Pixelated Light Reflectors and Locomotives.

PubMed

Ravi, Bolleddu; Chakraborty, Snigdha; Bhattacharjee, Mitradip; Mitra, Shirsendu; Ghosh, Abir; Gooh Pattader, Partho Sarathi; Bandyopadhyay, Dipankar

2017-01-11

Chemical pattern directed spin-dewetting of a macroscopic droplet composed of a dilute organic solution of liquid crystal (LC) formed an ordered array of micro- and nanoscale LC droplets. Controlled evaporation of the spin-dewetted droplets through vacuum drying could further miniaturize the size to the level of ∼90 nm. The size, periodicity, and spacing of these mesoscale droplets could be tuned with the variations in the initial loading of LC in the organic solution, the strength of the centripetal force on the droplet, and the duration of the evaporation. A simple theoretical model was developed to predict the spacing between the spin-dewetted droplets. The patterned LC droplets showed a reversible phase transition from nematic to isotropic and vice versa with the periodic exposure of a solvent vapor and its removal. A similar phase transition behavior was also observed with the periodic increase or reduction of temperature, suggesting their usefulness as vapor or temperature sensors. Interestingly, when the spin-dewetted droplets were confined between a pair of electrodes and an external electric field was applied, the droplets situated at the hydrophobic patches showed light-reflecting properties under the polarization microscopy highlighting their importance in the development of micro- or nanoscale LC displays. The digitized LC droplets, which were stationary otherwise, showed dielectrophoretic locomotion under the guidance of the external electric field beyond a threshold intensity of the field. Remarkably, the motion of these droplets could be restricted to the hydrophilic zones, which were confined between the hydrophobic patches of the chemically patterned surface. The findings could significantly contribute in the development of futuristic vapor or temperature sensors, light reflectors, and self-propellers using the micro- or nanoscale digitized LC droplets.

Applications of Digitized 3-D Position-Sensitive CdZnTe Spectrometers for National Security and Nuclear Nonproliferation

NASA Astrophysics Data System (ADS)

Streicher, Michael W.

A nuclear weapon detonation remains one of the gravest threats to the global community. Although the likelihood of a nuclear event remains small, the economic and political ramifications of an event are vast. The surest way to reduce the probability of an incident is to account for the special nuclear materials (SNM) which can be used to produce a nuclear weapon. Materials which can be used to manufacture a radiological dispersion device ("dirty bomb") must also be monitored. Rapidly-deployable, commercially-available, room-temperature imaging gamma-ray spectrometers are improving the ability of authorities to intelligently and quickly respond to threats. New electronics which digitally-sample the radiation-induced signals in CdZnTe detectors have expanded the capabilities of these sensors. This thesis explores national security applications where digital readout of CdZnTe detectors significantly enhances capabilities. Radioactive sources can be detected more quickly using digitally-sampled CdZnTe detector due to the improved energy resolution. The excellent energy resolution also improves the accuracy of measurements of uranium enrichment and allows users to measure plutonium grade. Small differences in the recorded gamma-ray energy spectrum can be used to estimate the effective atomic number and mass thickness of materials shielding SNM sources. Improved position resolution of gamma-ray interactions through digital readout allows high resolution gamma-ray images of SNM revealing information about the source configuration. CdZnTe sensors can detect the presence of neutrons, indirectly, through measurement of gamma rays released during capture of thermal neutrons by Cd-113 or inelastic scattering with any constituent nuclei. Fast neutrons, such as those released following fission, can be directly detected through elastic scattering interactions in the detector. Neutrons are a strong indicator of fissile material, and the background neutron rate is much lower than the gamma-ray background rate. Neutrons can more easily penetrate shielding materials as well which can greatly aid in the detection of shielded SNM. Digital CdZnTe readout enables the sensors to maintain excellent energy resolution at high count rates. Pulse pile-up and preamplifier decay can be monitored and corrected for on an event-by-event basis limiting energy resolution degradation in dose rates higher than 100 mR/hr. Finally, new iterations of the digital electronics have enhanced gamma-ray detection capabilities at high photon energies. Currently, gamma rays with energy up to 4.4 MeV have been detected. High-energy photon detection is critical for many proposed active interrogation systems.

Discrimination of complex mixtures by a colorimetric sensor array: coffee aromas.

PubMed

Suslick, Benjamin A; Feng, Liang; Suslick, Kenneth S

2010-03-01

The analysis of complex mixtures presents a difficult challenge even for modern analytical techniques, and the ability to discriminate among closely similar such mixtures often remains problematic. Coffee provides a readily available archetype of such highly multicomponent systems. The use of a low-cost, sensitive colorimetric sensor array for the detection and identification of coffee aromas is reported. The color changes of the sensor array were used as a digital representation of the array response and analyzed with standard statistical methods, including principal component analysis (PCA) and hierarchical clustering analysis (HCA). PCA revealed that the sensor array has exceptionally high dimensionality with 18 dimensions required to define 90% of the total variance. In quintuplicate runs of 10 commercial coffees and controls, no confusions or errors in classification by HCA were observed in 55 trials. In addition, the effects of temperature and time in the roasting of green coffee beans were readily observed and distinguishable with a resolution better than 10 degrees C and 5 min, respectively. Colorimetric sensor arrays demonstrate excellent potential for complex systems analysis in real-world applications and provide a novel method for discrimination among closely similar complex mixtures.

Presentation of a complex permittivity-meter with applications for sensing the moisture and salinity of a porous media.

PubMed

Chavanne, Xavier; Frangi, Jean-Pierre

2014-08-26

This paper describes a sensor dedicated to measuring the vertical profile of the complex permittivity and the temperature of any medium in which sensor electrodes are inserted. Potential applications are the estimate of the humidity and salinity in a porous medium, such as a soil. It consists of vertically-stacked capacitors along two conductive parallel cylinders of 5 cm in diameter and at a 10-cm distance to scan a significant volume of the medium (~1 L). It measures their admittances owing to a self-balanced impedance bridge operating at a frequency in the range of 1-20 MHz, possibly 30 MHz. Thanks to accurate design and electronic circuit theory-based modeling, the determination of the admittances takes into account all distortions due to lead and bridge electromagnetic effects inside the sensor when working at high frequencies. Calibration procedures and uncertainties are presented. The article also describes developments to make the present sensor autonomous on digital acquisition, basic data treatment and energy, as well as able to transfer stored data by a radio link. These steps in progress are prerequisites for a wireless network of sensors.

Discrimination of Complex Mixtures by a Colorimetric Sensor Array: Coffee Aromas

PubMed Central

Suslick, Benjamin A.; Feng, Liang; Suslick, Kenneth S.

2010-01-01

The analysis of complex mixtures presents a difficult challenge even for modern analytical techniques, and the ability to discriminate among closely similar such mixtures often remains problematic. Coffee provides a readily available archetype of such highly multicomponent systems. The use of a low-cost, sensitive colorimetric sensor array for the detection and identification of coffee aromas is reported. The color changes of the sensor array were used as a digital representation of the array response and analyzed with standard statistical methods, including principal component analysis (PCA) and hierarchical clustering analysis (HCA). PCA revealed that the sensor array has exceptionally high dimensionality with 18 dimensions required to define 90% of the total variance. In quintuplicate runs of 10 commercial coffees and controls, no confusions or errors in classification by HCA were observed in 55 trials. In addition, the effects of temperature and time in the roasting of green coffee beans were readily observed and distinguishable with a resolution better than 10 °C and 5 min, respectively. Colorimetric sensor arrays demonstrate excellent potential for complex systems analysis in real-world applications and provide a novel method for discrimination among closely similar complex mixtures. PMID:20143838

Presentation of a Complex Permittivity-Meter with Applications for Sensing the Moisture and Salinity of a Porous Media

PubMed Central

Chavanne, Xavier; Frangi, Jean-Pierre

2014-01-01

This paper describes a sensor dedicated to measuring the vertical profile of the complex permittivity and the temperature of any medium in which sensor electrodes are inserted. Potential applications are the estimate of the humidity and salinity in a porous medium, such as a soil. It consists of vertically-stacked capacitors along two conductive parallel cylinders of 5 cm in diameter and at a 10-cm distance to scan a significant volume of the medium (∼1 L). It measures their admittances owing to a self-balanced impedance bridge operating at a frequency in the range of 1–20 MHz, possibly 30 MHz. Thanks to accurate design and electronic circuit theory-based modeling, the determination of the admittances takes into account all distortions due to lead and bridge electromagnetic effects inside the sensor when working at high frequencies. Calibration procedures and uncertainties are presented. The article also describes developments to make the present sensor autonomous on digital acquisition, basic data treatment and energy, as well as able to transfer stored data by a radio link. These steps in progress are prerequisites for a wireless network of sensors. PMID:25162233

Device for self-verifying temperature measurement and control

DOEpatents

Watkins, Arthur D.; Cannon, Collins P.; Tolle, Charles R.

2004-08-03

A measuring instrument includes a first temperature sensor, a second temperature sensor and circuitry. The first and second temperature sensors each generate a signal indicative of the temperature of a medium being detected. The circuitry is configured to activate verification of temperature being sensed with the first sensor. According to one construction, the first temperature sensor comprises at least one thermocouple temperature sensor and the second temperature sensor comprises an optical temperature sensor, each sensor measuring temperature over the same range of temperature, but using a different physical phenomena. Also according to one construction, the circuitry comprises a computer configured to detect failure of one of the thermocouples by comparing temperature of the optical temperature sensor with each of the thermocouple temperature sensors. Even further, an output control signal is generated via a fuzzy inference machine and control apparatus.

Device and method for self-verifying temperature measurement and control

DOEpatents

Watkins, Arthur D.; Cannon, Collins P.; Tolle, Charles R.

2002-10-29

A measuring instrument includes a first temperature sensor, a second temperature sensor and circuitry. The first and second temperature sensors each generate a signal indicative of the temperature of a medium being detected. The circuitry is configured to activate verification of temperature being sensed with the first sensor. According to one construction, the first temperature sensor comprises at least one thermocouple temperature sensor and the second temperature sensor comprises an optical temperature sensor, each sensor measuring temperature over the same range of temperature, but using a different physical phenomena. Also according to one construction, the circuitry comprises a computer configured to detect failure of one of the thermocouples by comparing temperature of the optical temperature sensor with each of the thermocouple temperature sensors. Even further, an output control signal is generated via a fuzzy inference machine and control apparatus.

Analysis and Calibration of Sources of Electronic Error in PSD Sensor Response.

PubMed

Rodríguez-Navarro, David; Lázaro-Galilea, José Luis; Bravo-Muñoz, Ignacio; Gardel-Vicente, Alfredo; Tsirigotis, Georgios

2016-04-29

In order to obtain very precise measurements of the position of agents located at a considerable distance using a sensor system based on position sensitive detectors (PSD), it is necessary to analyze and mitigate the factors that generate substantial errors in the system's response. These sources of error can be divided into electronic and geometric factors. The former stem from the nature and construction of the PSD as well as the performance, tolerances and electronic response of the system, while the latter are related to the sensor's optical system. Here, we focus solely on the electrical effects, since the study, analysis and correction of these are a prerequisite for subsequently addressing geometric errors. A simple calibration method is proposed, which considers PSD response, component tolerances, temperature variations, signal frequency used, signal to noise ratio (SNR), suboptimal operational amplifier parameters, and analog to digital converter (ADC) quantitation SNRQ, etc. Following an analysis of these effects and calibration of the sensor, it was possible to correct the errors, thus rendering the effects negligible, as reported in the results section.

The Phoenix TECP Relative Humidity Sensor: Revised Results

NASA Technical Reports Server (NTRS)

Zent, Aaron

2014-01-01

The original calibration function of the RH sensor on the Phoenix mission's Thermal and Electrical Conductivity Sensor (TECP), has been revised to correct the erroneously-published original calibration equation, to demonstrate the value of this unique data set, and to improve characterization of H2O exchange between the martian regolith and atmosphere. TECP returned two data streams, the temperature of the electronics analog board (Tb) and the digital 12-bit output of the RH sensor (DN), both of which are required to uniquely specify the H2O abundance. Because the original flight instrument calibration was performed against a pair of hygrometers that measured frost point (Tf), the revised calibration equation is also cast in terms of frost point. The choice of functional form for the calibration function is minimally constrained. A series of profiles across the calibration data cloud at constant DN and Tb does not reveal any evidence of a complex functional form. Therefore, a series of polynomials in both DN and Tb was investigated, along with several non-linear functions of DN and Tb.

Micro flow-through PCR in a PMMA chip fabricated by KrF excimer laser.

PubMed

Yao, Liying; Liu, Baoan; Chen, Tao; Liu, Shibing; Zuo, Tiechuan

2005-09-01

As the third PCR technology, micro flow-through PCR chip can amplify DNA specifically in an exponential fashion in vitro. Nowadays many academies in the world have successfully amplified DNA using their own-made flow-through PCR chip. In this paper, the ablation principle of PMMA at 248 nm excimer laser was studied, then a PMMA based flow-through PCR chip with 20 cycles was fabricated by excimer laser at 19 kv and 18 mm/min. The chip was bonded together with another cover chip at 105( composite function)C, 160 N and 20 minutes. In the end, it was integrated with electrical thermal thin films and Pt 100 temperature sensors. The temperature controllers was built standard PID digital temperature controller, the temperature control precision was +/- 0.2( composite function)C. The temperature grads between the three temperature zones were 16.5 and 22.2( composite function)C respectively, the gaps between the temperature zones could realize heat insulation.

Implementation of a Target State Estimator for the Air-to-Air Attack Mode of the AFTI/F-16.

DTIC Science & Technology

1987-12-01

presents a discussion of the portion of the AFTI/F-16 aircraft relative to this thesis, including sensors and the digital flight control system ( DFCS ...system ( DFCS ). All sensor data are digitized and sent to one or more digital computers for processing. The flight control computers convert flight...the square of the magnitude of the target’s inertial turn rate, is developed from the application of the Coriolis theorem, written as Id Td dt dt

Analytical redundancy management mechanization and flight data analysis for the F-8 digital fly-by-wire aircraft flight control sensors

NASA Technical Reports Server (NTRS)

Deckert, J. C.

1983-01-01

The details are presented of an onboard digital computer algorithm designed to reliably detect and isolate the first failure in a duplex set of flight control sensors aboard the NASA F-8 digital fly-by-wire aircraft. The algorithm's successful flight test program is summarized, and specific examples are presented of algorithm behavior in response to software-induced signal faults, both with and without aircraft parameter modeling errors.

Investigation of the rolling motion of a hollow cylinder using a smartphone’s digital compass

NASA Astrophysics Data System (ADS)

Wattanayotin, Phattara; Puttharugsa, Chokchai; Khemmani, Supitch

2017-07-01

This study used a smartphone’s digital compass to observe the rolling motion of a hollow cylinder on an inclined plane. The smartphone (an iPhone 4s) was attached to the end of one side of a hollow cylinder to record the experimental data using the SensorLog application. In the experiment, the change of angular position was measured by the smartphone’s digital compass. The obtained results were then analyzed and calculated to determine various parameters of the motion, such as the angular velocity, angular acceleration, critical angle, and coefficient of static friction. The experimental results obtained from using the digital compass were compared with those obtained from using a gyroscope sensor. Moreover, the results obtained from both sensors were consistent with the calculations for the rolling motion. We expect that this experiment will be valuable for use in physics laboratories.

Network device interface for digitally interfacing data channels to a controller via a network

NASA Technical Reports Server (NTRS)

Konz, Daniel W. (Inventor); Ellerbrock, Philip J. (Inventor); Grant, Robert L. (Inventor); Winkelmann, Joseph P. (Inventor)

2006-01-01

The present invention provides a network device interface and method for digitally connecting a plurality of data channels, such as sensors, actuators, and subsystems, to a controller using a network bus. The network device interface interprets commands and data received from the controller and polls the data channels in accordance with these commands. Specifically, the network device interface receives digital commands and data from the controller, and based on these commands and data, communicates with the data channels to either retrieve data in the case of a sensor or send data to activate an actuator. Data retrieved from the sensor is then converted into digital signals and transmitted back to the controller. In one embodiment, the bus controller sends commands and data a defined bit rate, and the network device interface senses this bit rate and sends data back to the bus controller using the defined bit rate.

Network device interface for digitally interfacing data channels to a controller via a network

NASA Technical Reports Server (NTRS)

Ellerbrock, Philip J. (Inventor); Grant, Robert L. (Inventor); Konz, Daniel W. (Inventor); Winkelmann, Joseph P. (Inventor)

2005-01-01

The present invention provides a network device interface and method for digitally connecting a plurality of data channels, such as sensors, actuators, and subsystems, to a controller using a network bus. The network device interface interprets commands and data received from the controller and polls the data channels in accordance with these commands. Specifically, the network device interface receives digital commands and data from the controller, and based on these commands and data, communicates with the data channels to either retrieve data in the case of a sensor or send data to activate an actuator. Data retrieved from the sensor is then converted by the network device interface into digital signals and transmitted back to the controller. In one advantageous embodiment, the network device interface uses a specialized protocol for communicating across the network bus that uses a low-level instruction set and has low overhead for data communication.

Network device interface for digitally interfacing data channels to a controller via a network

NASA Technical Reports Server (NTRS)

Konz, Daniel W. (Inventor); Winkelmann, Joseph P. (Inventor); Ellerbrock, Philip J. (Inventor); Grant, Robert L. (Inventor)

2007-01-01

The present invention provides a network device interface and method for digitally connecting a plurality of data channels, such as sensors, actuators, and subsystems, to a controller using a network bus. The network device interface interprets commands and data received from the controller and polls the data channels in accordance with these commands. Specifically, the network device interface receives digital commands and data from the controller, and based on these commands and data, communicates with the data channels to either retrieve data in the case of a sensor or send data to activate an actuator. Data retrieved from the sensor is converted into digital signals and transmitted to the controller. In some embodiments, network device interfaces associated with different data channels coordinate communications with the other interfaces based on either a transition in a command message sent by the bus controller or a synchronous clock signal.

Network device interface for digitally interfacing data channels to a controller via a network

NASA Technical Reports Server (NTRS)

Ellerbrock, Philip J. (Inventor); Grant, Robert L. (Inventor); Winkelmann, Joseph P. (Inventor); Konz, Daniel W. (Inventor)

2009-01-01

A communications system and method are provided for digitally connecting a plurality of data channels, such as sensors, actuators, and subsystems, to a controller using a network bus. The network device interface interprets commands and data received from the controller and polls the data channels in accordance with these commands. Specifically, the network device interface receives digital commands and data from the controller, and based on these commands and data, communicates with the data channels to either retrieve data in the case of a sensor or send data to activate an actuator. Data retrieved from the sensor is converted into digital signals and transmitted to the controller. Network device interfaces associated with different data channels can coordinate communications with the other interfaces based on either a transition in a command message sent by the bus controller or a synchronous clock signal.

Network device interface for digitally interfacing data channels to a controller via a network

NASA Technical Reports Server (NTRS)

Ellerbrock, Philip J. (Inventor); Winkelmann, Joseph P. (Inventor); Grant, Robert L. (Inventor); Konz, Daniel W. (Inventor)

2006-01-01

The present invention provides a network device interface and method for digitally connecting a plurality of data channels, such as sensors, actuators, and subsystems, to a controller using a network bus. The network device interface interprets commands and data received from the controller and polls the data channels in accordance with these commands. Specifically, the network device interface receives digital commands and data from the controller, and based on these commands and data, communicates with the data channels to either retrieve data in the case of a sensor or send data to activate an actuator. Data retrieved from the sensor is then converted by the network device interface into digital signals and transmitted back to the controller. In one advantageous embodiment, the network device interface is a state machine, such as an ASIC, that operates independent of a processor in communicating with the bus controller and data channels.

Network device interface for digitally interfacing data channels to a controller via a network

NASA Technical Reports Server (NTRS)

Ellerbrock, Philip J. (Inventor); Konz, Daniel W. (Inventor); Winkelmann, Joseph P. (Inventor); Grant, Robert L. (Inventor)

2004-01-01

The present invention provides a network device interface and method for digitally connecting a plurality of data channels, such as sensors, actuators, and subsystems, to a controller using a network bus. The network device interface interprets commands and data received from the controller and polls the data channels in accordance with these commands. Specifically, the network device interface receives digital commands and data from the controller, and based on these commands and data, communicates with the data channels to either retrieve data in the case of a sensor or send data to activate an actuator. Data retrieved from the sensor is then converted by the network device interface into digital signals and transmitted back to the controller. In one advantageous embodiment, the network device interface uses a specialized protocol for communicating across the network bus that uses a low-level instruction set and has low overhead for data communication.

RFQ accelerator tuning system

DOEpatents

Bolie, V.W.

1990-07-03

A cooling system is provided for maintaining a preselected operating temperature in a device, which may be an RFQ accelerator, having a variable heat removal requirement, by circulating a cooling fluid through a cooling system remote from the device. Internal sensors in the device enable an estimated error signal to be generated from parameters which are indicative of the heat removal requirement from the device. Sensors are provided at predetermined locations in the cooling system for outputting operational temperature signals. Analog and digital computers define a control signal functionally related to the temperature signals and the estimated error signal, where the control signal is defined effective to return the device to the preselected operating temperature in a stable manner. The cooling system includes a first heat sink responsive to a first portion of the control signal to remove heat from a major portion of the circulating fluid. A second heat sink is responsive to a second portion of the control signal to remove heat from a minor portion of the circulating fluid. The cooled major and minor portions of the circulating fluid are mixed in response to a mixing portion of the control signal, which is effective to proportion the major and minor portions of the circulating fluid to establish a mixed fluid temperature which is effective to define the preselected operating temperature for the remote device. In an RFQ environment the stable temperature control enables the resonant frequency of the device to be maintained at substantially a predetermined value during transient operations. 3 figs.

RFQ accelerator tuning system

DOEpatents

Bolie, Victor W.

1990-01-01

A cooling system is provided for maintaining a preselected operating temperature in a device, which may be an RFQ accelerator, having a variable heat removal requirement, by circulating a cooling fluid through a cooling system remote from the device. Internal sensors in the device enable an estimated error signal to be generated from parameters which are indicative of the heat removal requirement from the device. Sensors are provided at predetermined locations in the cooling system for outputting operational temperature signals. Analog and digital computers define a control signal functionally related to the temperature signals and the estimated error signal, where the control signal is defined effective to return the device to the preselected operating temperature in a stable manner. The cooling system includes a first heat sink responsive to a first portion of the control signal to remove heat from a major portion of the circulating fluid. A second heat sink is responsive to a second portion of the control signal to remove heat from a minor portion of the circulating fluid. The cooled major and minor portions of the circulating fluid are mixed in response to a mixing portion of the control signal, which is effective to proportion the major and minor portions of the circulating fluid to establish a mixed fluid temperature which is effective to define the preselected operating temperature for the remote device. In an RFQ environment the stable temperature control enables the resonant frequency of the device to be maintained at substantially a predetermined value during transient operations.

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

A Capacitance-To-Digital Converter for MEMS Sensors for Smart Applications.

PubMed

Pérez Sanjurjo, Javier; Prefasi, Enrique; Buffa, Cesare; Gaggl, Richard

2017-06-07

The use of MEMS sensors has been increasing in recent years. To cover all the applications, many different readout circuits are needed. To reduce the cost and time to market, a generic capacitance-to-digital converter (CDC) seems to be the logical next step. This work presents a configurable CDC designed for capacitive MEMS sensors. The sensor is built with a bridge of MEMS, where some of them function with pressure. Then, the capacitive to digital conversion is realized using two steps. First, a switched-capacitor (SC) preamplifier is used to make the capacitive to voltage (C-V) conversion. Second, a self-oscillated noise-shaping integrating dual-slope (DS) converter is used to digitize this magnitude. The proposed converter uses time instead of amplitude resolution to generate a multibit digital output stream. In addition it performs noise shaping of the quantization error to reduce measurement time. This article shows the effectiveness of this method by measurements performed on a prototype, designed and fabricated using standard 0.13 µm CMOS technology. Experimental measurements show that the CDC achieves a resolution of 17 bits, with an effective area of 0.317 mm², which means a pressure resolution of 1 Pa, while consuming 146 µA from a 1.5 V power supply.

A Capacitance-To-Digital Converter for MEMS Sensors for Smart Applications

PubMed Central

Pérez Sanjurjo, Javier; Prefasi, Enrique; Buffa, Cesare; Gaggl, Richard

2017-01-01

The use of MEMS sensors has been increasing in recent years. To cover all the applications, many different readout circuits are needed. To reduce the cost and time to market, a generic capacitance-to-digital converter (CDC) seems to be the logical next step. This work presents a configurable CDC designed for capacitive MEMS sensors. The sensor is built with a bridge of MEMS, where some of them function with pressure. Then, the capacitive to digital conversion is realized using two steps. First, a switched-capacitor (SC) preamplifier is used to make the capacitive to voltage (C-V) conversion. Second, a self-oscillated noise-shaping integrating dual-slope (DS) converter is used to digitize this magnitude. The proposed converter uses time instead of amplitude resolution to generate a multibit digital output stream. In addition it performs noise shaping of the quantization error to reduce measurement time. This article shows the effectiveness of this method by measurements performed on a prototype, designed and fabricated using standard 0.13 µm CMOS technology. Experimental measurements show that the CDC achieves a resolution of 17 bits, with an effective area of 0.317 mm2, which means a pressure resolution of 1 Pa, while consuming 146 µA from a 1.5 V power supply. PMID:28590425

Fiber-optic extrinsic Fabry-Perot interferometer strain sensor with <50 pm displacement resolution using three-wavelength digital phase demodulation.

PubMed

Schmidt, M; Werther, B; Fuerstenau, N; Matthias, M; Melz, T

2001-04-09

A fiber-optic extrinsic Fabry-Perot interferometer strain sensor (EFPI-S) of ls = 2.5 cm sensor length using three-wavelength digital phase demodulation is demonstrated to exhibit <50 pm displacement resolution (<2nm/m strain resolution) when measuring the cross expansion of a PZT-ceramic plate. The sensing (single-mode downlead-) and reflecting fibers are fused into a 150/360 microm capillary fiber where the fusion points define the sensor length. Readout is performed using an improved version of the previously described three-wavelength digital phase demodulation method employing an arctan-phase stepping algorithm. In the resent experiments the strain sensitivity was varied via the mapping of the arctan - lookup table to the 16-Bit DA-converter range from 188.25 k /V (6 Volt range 1130 k ) to 11.7 k /Volt (range 70 k ).

Design, Simulation and Characteristics Research of the Interface Circuit based on nano-polysilicon thin films pressure sensor

NASA Astrophysics Data System (ADS)

Zhao, Xiaosong; Zhao, Xiaofeng; Yin, Liang

2018-03-01

This paper presents a interface circuit for nano-polysilicon thin films pressure sensor. The interface circuit includes consist of instrument amplifier and Analog-to-Digital converter (ADC). The instrumentation amplifier with a high common mode rejection ratio (CMRR) is implemented by three stages current feedback structure. At the same time, in order to satisfy the high precision requirements of pressure sensor measure system, the 1/f noise corner of 26.5 mHz can be achieved through chopping technology at a noise density of 38.2 nV/sqrt(Hz).Ripple introduced by chopping technology adopt continuous ripple reduce circuit (RRL), which achieves the output ripple level is lower than noise. The ADC achieves 16 bits significant digit by adopting sigma-delta modulator with fourth-order single-bit structure and digital decimation filter, and finally achieves high precision integrated pressure sensor interface circuit.

A CMOS image sensor with stacked photodiodes for lensless observation system of digital enzyme-linked immunosorbent assay

NASA Astrophysics Data System (ADS)

Takehara, Hironari; Miyazawa, Kazuya; Noda, Toshihiko; Sasagawa, Kiyotaka; Tokuda, Takashi; Kim, Soo Hyeon; Iino, Ryota; Noji, Hiroyuki; Ohta, Jun

2014-01-01

A CMOS image sensor with stacked photodiodes was fabricated using 0.18 µm mixed signal CMOS process technology. Two photodiodes were stacked at the same position of each pixel of the CMOS image sensor. The stacked photodiodes consist of shallow high-concentration N-type layer (N+), P-type well (PW), deep N-type well (DNW), and P-type substrate (P-sub). PW and P-sub were shorted to ground. By monitoring the voltage of N+ and DNW individually, we can observe two monochromatic colors simultaneously without using any color filters. The CMOS image sensor is suitable for fluorescence imaging, especially contact imaging such as a lensless observation system of digital enzyme-linked immunosorbent assay (ELISA). Since the fluorescence increases with time in digital ELISA, it is possible to observe fluorescence accurately by calculating the difference from the initial relation between the pixel values for both photodiodes.

Zero-power infrared digitizers based on plasmonically enhanced micromechanical photoswitches

NASA Astrophysics Data System (ADS)

Qian, Zhenyun; Kang, Sungho; Rajaram, Vageeswar; Cassella, Cristian; McGruer, Nicol E.; Rinaldi, Matteo

2017-10-01

State-of-the-art sensors use active electronics to detect and discriminate light, sound, vibration and other signals. They consume power constantly, even when there is no relevant data to be detected, which limits their lifetime and results in high costs of deployment and maintenance for unattended sensor networks. Here we propose a device concept that fundamentally breaks this paradigm—the sensors remain dormant with near-zero power consumption until awakened by a specific physical signature associated with an event of interest. In particular, we demonstrate infrared digitizing sensors that consist of plasmonically enhanced micromechanical photoswitches (PMPs) that selectively harvest the impinging electromagnetic energy in design-defined spectral bands of interest, and use it to create mechanically a conducting channel between two electrical contacts, without the need for any additional power source. Our zero-power digitizing sensor prototypes produce a digitized output bit (that is, a large and sharp off-to-on state transition with an on/off conductance ratio >1012 and subthreshold slope >9 dec nW-1) when exposed to infrared radiation in a specific narrow spectral band (∼900 nm bandwidth in the mid-infrared) with the intensity above a power threshold of only ∼500 nW, which is not achievable with any existing photoswitch technologies.

Integrated High Resolution Digital Color Light Sensor in 130 nm CMOS Technology.

PubMed

Strle, Drago; Nahtigal, Uroš; Batistell, Graciele; Zhang, Vincent Chi; Ofner, Erwin; Fant, Andrea; Sturm, Johannes

2015-07-22

This article presents a color light detection system integrated in 130 nm CMOS technology. The sensors and corresponding electronics detect light in a CIE XYZ color luminosity space using on-chip integrated sensors without any additional process steps, high-resolution analog-to-digital converter, and dedicated DSP algorithm. The sensor consists of a set of laterally arranged integrated photodiodes that are partly covered by metal, where color separation between the photodiodes is achieved by lateral carrier diffusion together with wavelength-dependent absorption. A high resolution, hybrid, ∑∆ ADC converts each photo diode's current into a 22-bit digital result, canceling the dark current of the photo diodes. The digital results are further processed by the DSP, which calculates normalized XYZ or RGB color and intensity parameters using linear transformations of the three photo diode responses by multiplication of the data with a transformation matrix, where the coefficients are extracted by training in combination with a pseudo-inverse operation and the least-mean square approximation. The sensor system detects the color light parameters with 22-bit accuracy, consumes less than 60 μA on average at 10 readings per second, and occupies approx. 0.8 mm(2) of silicon area (including three photodiodes and the analog part of the ADC). The DSP is currently implemented on FPGA.

High-speed line-scan camera with digital time delay integration

NASA Astrophysics Data System (ADS)

Bodenstorfer, Ernst; Fürtler, Johannes; Brodersen, Jörg; Mayer, Konrad J.; Eckel, Christian; Gravogl, Klaus; Nachtnebel, Herbert

2007-02-01

Dealing with high-speed image acquisition and processing systems, the speed of operation is often limited by the amount of available light, due to short exposure times. Therefore, high-speed applications often use line-scan cameras, based on charge-coupled device (CCD) sensors with time delayed integration (TDI). Synchronous shift and accumulation of photoelectric charges on the CCD chip - according to the objects' movement - result in a longer effective exposure time without introducing additional motion blur. This paper presents a high-speed color line-scan camera based on a commercial complementary metal oxide semiconductor (CMOS) area image sensor with a Bayer filter matrix and a field programmable gate array (FPGA). The camera implements a digital equivalent to the TDI effect exploited with CCD cameras. The proposed design benefits from the high frame rates of CMOS sensors and from the possibility of arbitrarily addressing the rows of the sensor's pixel array. For the digital TDI just a small number of rows are read out from the area sensor which are then shifted and accumulated according to the movement of the inspected objects. This paper gives a detailed description of the digital TDI algorithm implemented on the FPGA. Relevant aspects for the practical application are discussed and key features of the camera are listed.

Scanning hall probe microscopy (SHPM) using quartz crystal AFM feedback.

PubMed

Dede, M; Urkmen, K; Girişen, O; Atabak, M; Oral, A; Farrer, I; Ritchie, D

2008-02-01

Scanning Hall Probe Microscopy (SHPM) is a quantitative and non-invasive technique for imaging localized surface magnetic field fluctuations such as ferromagnetic domains with high spatial and magnetic field resolution of approximately 50 nm and 7 mG/Hz(1/2) at room temperature. In the SHPM technique, scanning tunneling microscope (STM) or atomic force microscope (AFM) feedback is used to keep the Hall sensor in close proximity of the sample surface. However, STM tracking SHPM requires conductive samples; therefore the insulating substrates have to be coated with a thin layer of gold. This constraint can be eliminated with the AFM feedback using sophisticated Hall probes that are integrated with AFM cantilevers. However it is very difficult to micro fabricate these sensors. In this work, we have eliminated the difficulty in the cantilever-Hall probe integration process, just by gluing a Hall Probe chip to a quartz crystal tuning fork force sensor. The Hall sensor chip is simply glued at the end of a 32.768 kHz or 100 kHz Quartz crystal, which is used as force sensor. An LT-SHPM system is used to scan the samples. The sensor assembly is dithered at the resonance frequency using a digital Phase Locked Loop circuit and frequency shifts are used for AFM tracking. SHPM electronics is modified to detect AFM topography and the frequency shift, along with the magnetic field image. Magnetic domains and topography of an Iron Garnet thin film crystal, NdFeB demagnetised magnet and hard disk samples are presented at room temperature. The performance is found to be comparable with the SHPM using STM feedback.

Optical Sensors for Use in Propulsion Control Systems

NASA Technical Reports Server (NTRS)

Fritsch, Klaus

1997-01-01

This final technical report describes the results of a cooperative effort which was originally established between John Carroll University and the Instrumentation and Control Technology Division at NASA Lewis Research Center on November, 1982, and then continued with the Engine Sensor Technology Branch at NASA Lewis until March, 1995. All work at John Carroll University was directed by the principal investigator of this grant, Klaus Fritsch, Ph.D. For the first two years of this grant this effort was supervised at NASA by Mr. Robert J. Baumbick and for the remainder of the grant by Dr. Glenn M. Beheim. All research was carried out in close cooperation with Dr. Beheim. Electrically passive optical sensors for measurands such as pressure, temperature, position, and rotational speed are required for aircraft engine control in fly-by-light digital aircraft control systems. Fiberoptic data links and optical multiplexing techniques should be used for combining and processing the outputs from several sensors, sharing as many optical end electronic parts as possible. The overall objective of this grant was to explore techniques for designing and constructing such electrically passive optical sensors for measuring physical parameters in jet aircraft engines and for use in aircraft control systems. We have concentrated our efforts on pressure, temperature, and position sensors employing techniques which are relatively immune to transmissivity variations of the fiber links and to variations in intensity of the light source. Infrared light-emitting diodes are employed because of their longevity and immunity to vibration. We have also studied a number of multiplexing techniques. On the following pages I will give thumbnail sketches of the projects carried out under this grant and provide references to publications and John Carroll M.S. theses which resulted directly from this work and which describe these projects in greater detail.

Developing hydrological monitoring networks with Arduino

NASA Astrophysics Data System (ADS)

Buytaert, Wouter; Vega, Andres; Villacis, Marcos; Moulds, Simon

2015-04-01

The open source hardware platform Arduino is very cost-effective and versatile for the development of sensor networks. Here we report on experiments on the use of Arduino-related technologies to develop and implement hydrological monitoring networks. Arduino Uno boards were coupled to a variety of commercially available hydrological sensors and programmed for automatic data collection. Tested sensors include water level, temperature, humidity, radiation, and precipitation. Our experiments show that most of the tested analogue sensors are quite straightforward to couple to Arduino based data loggers, especially if the electronic characteristics of the sensor are available. However, some sensors have internal digital interfaces, which are more challenging to connect. Lastly, tipping bucket rain gauges prove the most challenging because of the very specific methodology, i.e. registration of bucket tips instead of measurements at regular intervals. The typically low data generation rate of hydrological instruments is very compatible with available technologies for wireless data transmission. Mesh networks such as Xbee prove very convenient and robust for dispersed networks, while wifi is also an option for shorter distances and particular topographies. Lastly, the GSM shield of the Arduino can be used to transfer data to centralized databases. In regions where no mobile internet (i.e. 3G) connection is available, data transmission via text messages may be an option, depending on the bandwidth requirements.

Biometrics Foundation Documents

DTIC Science & Technology

2009-01-01

a digital form. The quality of the sensor used has a significant impact on the recognition results. Example “sensors” could be digital cameras...Difficult to control sensor and channel variances that significantly impact capabilities Not sufficiently distinctive for identification over large...expressions, hairstyle, glasses, hats, makeup, etc. have on face recognition systems? Minor variances , such as those mentioned, will have a moderate

Development open source microcontroller based temperature data logger

NASA Astrophysics Data System (ADS)

Abdullah, M. H.; Che Ghani, S. A.; Zaulkafilai, Z.; Tajuddin, S. N.

2017-10-01

This article discusses the development stages in designing, prototyping, testing and deploying a portable open source microcontroller based temperature data logger for use in rough industrial environment. The 5V powered prototype of data logger is equipped with open source Arduino microcontroller for integrating multiple thermocouple sensors with their module, secure digital (SD) card storage, liquid crystal display (LCD), real time clock and electronic enclosure made of acrylic. The program for the function of the datalogger is programmed so that 8 readings from the thermocouples can be acquired within 3 s interval and displayed on the LCD simultaneously. The recorded temperature readings at four different points on both hydrodistillation show similar profile pattern and highest yield of extracted oil was achieved on hydrodistillation 2 at 0.004%. From the obtained results, this study achieved the objective of developing an inexpensive, portable and robust eight channels temperature measuring module with capabilities to monitor and store real time data.

Photon-Number-Resolving Transition-Edge Sensors for the Metrology of Quantum Light Sources

NASA Astrophysics Data System (ADS)

Schmidt, M.; von Helversen, M.; López, M.; Gericke, F.; Schlottmann, E.; Heindel, T.; Kück, S.; Reitzenstein, S.; Beyer, J.

2018-05-01

Low-temperature photon-number-resolving detectors allow for direct access to the photon number distribution of quantum light sources and can thus be exploited to explore the photon statistics, e.g., solid-state-based non-classical light sources. In this work, we report on the setup and calibration of a detection system based on fiber-coupled tungsten transition-edge sensors (W-TESs). Our stand-alone system comprises two W-TESs, read out by two 2-stage-SQUID current sensors, operated in a compact detector unit that is integrated in an adiabatic demagnetization refrigerator. Fast low-noise analog amplifiers and digitizers are used for signal acquisition. The detection efficiency of the single-mode fiber-coupled detector system in the spectral region of interest (850-950 nm) is determined to be larger than 87 %. The presented detector system opens up new routes in the characterization of quantum light sources for quantum information, quantum-enhanced sensing and quantum metrology.

A simple algorithm for beam profile diagnostics using a thermographic camera

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

Katagiri, Ken; Hojo, Satoru; Honma, Toshihiro

2014-03-15

A new algorithm for digital image processing apparatuses is developed to evaluate profiles of high-intensity DC beams from temperature images of irradiated thin foils. Numerical analyses are performed to examine the reliability of the algorithm. To simulate the temperature images acquired by a thermographic camera, temperature distributions are numerically calculated for 20 MeV proton beams with different parameters. Noise in the temperature images which is added by the camera sensor is also simulated to account for its effect. Using the algorithm, beam profiles are evaluated from the simulated temperature images and compared with exact solutions. We find that niobium ismore » an appropriate material for the thin foil used in the diagnostic system. We also confirm that the algorithm is adaptable over a wide beam current range of 0.11–214 μA, even when employing a general-purpose thermographic camera with rather high noise (ΔT{sub NETD} ≃ 0.3 K; NETD: noise equivalent temperature difference)« less

Active-Pixel Image Sensor With Analog-To-Digital Converters

NASA Technical Reports Server (NTRS)

Fossum, Eric R.; Mendis, Sunetra K.; Pain, Bedabrata; Nixon, Robert H.

1995-01-01

Proposed single-chip integrated-circuit image sensor contains 128 x 128 array of active pixel sensors at 50-micrometer pitch. Output terminals of all pixels in each given column connected to analog-to-digital (A/D) converter located at bottom of column. Pixels scanned in semiparallel fashion, one row at time; during time allocated to scanning row, outputs of all active pixel sensors in row fed to respective A/D converters. Design of chip based on complementary metal oxide semiconductor (CMOS) technology, and individual circuit elements fabricated according to 2-micrometer CMOS design rules. Active pixel sensors designed to operate at video rate of 30 frames/second, even at low light levels. A/D scheme based on first-order Sigma-Delta modulation.

Digital camera auto white balance based on color temperature estimation clustering

NASA Astrophysics Data System (ADS)

Zhang, Lei; Liu, Peng; Liu, Yuling; Yu, Feihong

2010-11-01

Auto white balance (AWB) is an important technique for digital cameras. Human vision system has the ability to recognize the original color of an object in a scene illuminated by a light source that has a different color temperature from D65-the standard sun light. However, recorded images or video clips, can only record the original information incident into the sensor. Therefore, those recorded will appear different from the real scene observed by the human. Auto white balance is a technique to solve this problem. Traditional methods such as gray world assumption, white point estimation, may fail for scenes with large color patches. In this paper, an AWB method based on color temperature estimation clustering is presented and discussed. First, the method gives a list of several lighting conditions that are common for daily life, which are represented by their color temperatures, and thresholds for each color temperature to determine whether a light source is this kind of illumination; second, an image to be white balanced are divided into N blocks (N is determined empirically). For each block, the gray world assumption method is used to calculate the color cast, which can be used to estimate the color temperature of that block. Third, each calculated color temperature are compared with the color temperatures in the given illumination list. If the color temperature of a block is not within any of the thresholds in the given list, that block is discarded. Fourth, the remaining blocks are given a majority selection, the color temperature having the most blocks are considered as the color temperature of the light source. Experimental results show that the proposed method works well for most commonly used light sources. The color casts are removed and the final images look natural.

Design and Implementation of Readout Circuit with Threshold Voltage Compensation on Glass Substrate for Touch Panel Applications

NASA Astrophysics Data System (ADS)

Lin, Yu-Ta; Ker, Ming-Dou; Wang, Tzu-Ming

2011-03-01

A new on-panel readout circuit with threshold voltage compensation for capacitive sensor in low temperature polycrystalline silicon (poly-Si) thin-film transistor (LTPS-TFT) process has been proposed. In order to compensate the threshold voltage variation from LTPS process variation, the proposed readout circuit applies a novel compensation approach with switch capacitor technique. In addition, a 4-bit analog-to-digital converter (ADC) is added to identify different sensed capacitor values and further enhances the overall resolution of touch panel.

Temperature Sensing for Oil, Gas, and Structural Analysis

NASA Technical Reports Server (NTRS)

2006-01-01

In 1996, Systems and Processes Engineering Corporation (SPEC), of Austin, Texas, undertook a NASA Small Business Innovation Research (SBIR) contract with Langley Research Center to develop a compact and lightweight digital thermal sensing (DTS) system for monitoring the cryogenic tanks on the X-33 prototype aircraft. That technology, along with a processor developed by SPEC for Goddard Space Flight Center, was space-qualified and integrated into several NASA missions. SPEC formed an ancillary organization, SensorTran, Inc., to continue work developing the DTS technology for a variety of commercial and industrial applications.

WE-AB-BRA-11: Improved Imaging of Permanent Prostate Brachytherapy Seed Implants by Combining an Endorectal X-Ray Sensor with a CT Scanner

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

Steiner, J; Matthews, K; Jia, G

Purpose: To test feasibility of the use of a digital endorectal x-ray sensor for improved image resolution of permanent brachytherapy seed implants compared to conventional CT. Methods: Two phantoms simulating the male pelvic region were used to test the capabilities of a digital endorectal x-ray sensor for imaging permanent brachytherapy seed implants. Phantom 1 was constructed from acrylic plastic with cavities milled in the locations of the prostate and the rectum. The prostate cavity was filled a Styrofoam plug implanted with 10 training seeds. Phantom 2 was constructed from tissue-equivalent gelatins and contained a prostate phantom implanted with 18 strandsmore » of training seeds. For both phantoms, an intraoral digital dental x-ray sensor was placed in the rectum within 2 cm of the seed implants. Scout scans were taken of the phantoms over a limited arc angle using a CT scanner (80 kV, 120–200 mA). The dental sensor was removed from the phantoms and normal helical CT and scout (0 degree) scans using typical parameters for pelvic CT (120 kV, auto-mA) were collected. A shift-and add tomosynthesis algorithm was developed to localize seed plane location normal to detector face. Results: The endorectal sensor produced images with improved resolution compared to CT scans. Seed clusters and individual seed geometry were more discernable using the endorectal sensor. Seed 3D locations, including seeds that were not located in every projection image, were discernable using the shift and add algorithm. Conclusion: This work shows that digital endorectal x-ray sensors are a feasible method for improving imaging of permanent brachytherapy seed implants. Future work will consist of optimizing the tomosynthesis technique to produce higher resolution, lower dose images of 1) permanent brachytherapy seed implants for post-implant dosimetry and 2) fine anatomic details for imaging and managing prostatic disease compared to CT images. Funding: LSU Faculty Start-up Funding. Disclosure: XDR Radiography has loaned our research group the digital x-ray detector used in this work. CoI: None.« less

Digital Suicide Prevention: Can Technology Become a Game-changer?

PubMed

Vahabzadeh, Arshya; Sahin, Ned; Kalali, Amir

2016-01-01

Suicide continues to be a leading cause of death and has been recognized as a significant public health issue. Rapid advances in data science can provide us with useful tools for suicide prevention, and help to dynamically assess suicide risk in quantitative data-driven ways. In this article, the authors highlight the most current international research in digital suicide prevention, including the use of machine learning, smartphone applications, and wearable sensor driven systems. The authors also discuss future opportunities for digital suicide prevention, and propose a novel Sensor-driven Mental State Assessment System.

Color camera computed tomography imaging spectrometer for improved spatial-spectral image accuracy

NASA Technical Reports Server (NTRS)

Wilson, Daniel W. (Inventor); Bearman, Gregory H. (Inventor); Johnson, William R. (Inventor)

2011-01-01

Computed tomography imaging spectrometers ("CTIS"s) having color focal plane array detectors are provided. The color FPA detector may comprise a digital color camera including a digital image sensor, such as a Foveon X3.RTM. digital image sensor or a Bayer color filter mosaic. In another embodiment, the CTIS includes a pattern imposed either directly on the object scene being imaged or at the field stop aperture. The use of a color FPA detector and the pattern improves the accuracy of the captured spatial and spectral information.

Cryogenic Microcalorimeter System for Ultra-High Resolution Alpha-Particle Spectrometry

NASA Astrophysics Data System (ADS)

Croce, M. P.; Bacrania, M. K.; Hoover, A. S.; Rabin, M. W.; Hoteling, N. J.; LaMont, S. P.; Plionis, A. A.; Dry, D. E.; Ullom, J. N.; Bennett, D. A.; Horansky, R. D.; Kotsubo, V.; Cantor, R.

2009-12-01

Microcalorimeters have been shown to yield unsurpassed energy resolution for alpha spectrometry, up to 1.06 keV FWHM at 5.3 MeV. These detectors use a superconducting transition-edge sensor (TES) to measure the temperature change in an absorber from energy deposited by an interacting alpha particle. Our system has four independent detectors mounted inside a liquid nitrogen/liquid helium cryostat. An adiabatic demagnetization refrigerator (ADR) cools the detector stage to its operating temperature of 80 mK. Temperature regulation with ˜15-μK peak-to-peak variation is achieved by PID control of the ADR. The detectors are voltage-biased, and the current signal is amplified by a commercial SQUID readout system and digitized for further analysis. This paper will discuss design and operation of our microcalorimeter alpha-particle spectrometer, and will show recent results.

Virtual Sensor Test Instrumentation

NASA Technical Reports Server (NTRS)

Wang, Roy

2011-01-01

Virtual Sensor Test Instrumentation is based on the concept of smart sensor technology for testing with intelligence needed to perform sell-diagnosis of health, and to participate in a hierarchy of health determination at sensor, process, and system levels. A virtual sensor test instrumentation consists of five elements: (1) a common sensor interface, (2) microprocessor, (3) wireless interface, (4) signal conditioning and ADC/DAC (analog-to-digital conversion/ digital-to-analog conversion), and (5) onboard EEPROM (electrically erasable programmable read-only memory) for metadata storage and executable software to create powerful, scalable, reconfigurable, and reliable embedded and distributed test instruments. In order to maximize the efficient data conversion through the smart sensor node, plug-and-play functionality is required to interface with traditional sensors to enhance their identity and capabilities for data processing and communications. Virtual sensor test instrumentation can be accessible wirelessly via a Network Capable Application Processor (NCAP) or a Smart Transducer Interlace Module (STIM) that may be managed under real-time rule engines for mission-critical applications. The transducer senses the physical quantity being measured and converts it into an electrical signal. The signal is fed to an A/D converter, and is ready for use by the processor to execute functional transformation based on the sensor characteristics stored in a Transducer Electronic Data Sheet (TEDS). Virtual sensor test instrumentation is built upon an open-system architecture with standardized protocol modules/stacks to interface with industry standards and commonly used software. One major benefit for deploying the virtual sensor test instrumentation is the ability, through a plug-and-play common interface, to convert raw sensor data in either analog or digital form, to an IEEE 1451 standard-based smart sensor, which has instructions to program sensors for a wide variety of functions. The sensor data is processed in a distributed fashion across the network, providing a large pool of resources in real time to meet stringent latency requirements.

Digital phase demodulation for low-coherence interferometry-based fiber-optic sensors

NASA Astrophysics Data System (ADS)

Liu, Y.; Strum, R.; Stiles, D.; Long, C.; Rakhman, A.; Blokland, W.; Winder, D.; Riemer, B.; Wendel, M.

2018-03-01

We describe a digital phase demodulation scheme for low-coherence interferometry-based fiber-optic sensors by employing a simple generation of phase-shifted signals at the interrogation interferometer. The scheme allows a real-time calibration process and offers capability of measuring large variations (up to the coherence of the light source) at the bandwidth that is only limited by the data acquisition system. The proposed phase demodulation method is analytically derived and its validity and performance are experimentally verified using fiber-optic Fabry-Perot sensors for measurement of strains and vibrations.

Self-calibration for lensless color microscopy.

PubMed

Flasseur, Olivier; Fournier, Corinne; Verrier, Nicolas; Denis, Loïc; Jolivet, Frédéric; Cazier, Anthony; Lépine, Thierry

2017-05-01

Lensless color microscopy (also called in-line digital color holography) is a recent quantitative 3D imaging method used in several areas including biomedical imaging and microfluidics. By targeting cost-effective and compact designs, the wavelength of the low-end sources used is known only imprecisely, in particular because of their dependence on temperature and power supply voltage. This imprecision is the source of biases during the reconstruction step. An additional source of error is the crosstalk phenomenon, i.e., the mixture in color sensors of signals originating from different color channels. We propose to use a parametric inverse problem approach to achieve self-calibration of a digital color holographic setup. This process provides an estimation of the central wavelengths and crosstalk. We show that taking the crosstalk phenomenon into account in the reconstruction step improves its accuracy.

Reliable dual-redundant sensor failure detection and identification for the NASA F-8 DFBW aircraft

NASA Technical Reports Server (NTRS)

Deckert, J. C.; Desai, M. N.; Deyst, J. J., Jr.; Willsky, A. S.

1978-01-01

A technique was developed which provides reliable failure detection and identification (FDI) for a dual redundant subset of the flight control sensors onboard the NASA F-8 digital fly by wire (DFBW) aircraft. The technique was successfully applied to simulated sensor failures on the real time F-8 digital simulator and to sensor failures injected on telemetry data from a test flight of the F-8 DFBW aircraft. For failure identification the technique utilized the analytic redundancy which exists as functional and kinematic relationships among the various quantities being measured by the different control sensor types. The technique can be used not only in a dual redundant sensor system, but also in a more highly redundant system after FDI by conventional voting techniques reduced to two the number of unfailed sensors of a particular type. In addition the technique can be easily extended to the case in which only one sensor of a particular type is available.

Optimization of the coplanar interdigital capacitive sensor

NASA Astrophysics Data System (ADS)

Huang, Yunzhi; Zhan, Zheng; Bowler, Nicola

2017-02-01

Interdigital capacitive sensors are applied in nondestructive testing and material property characterization of low-conductivity materials. The sensor performance is typically described based on the penetration depth of the electric field into the sample material, the sensor signal strength and its sensitivity. These factors all depend on the geometry and material properties of the sensor and sample. In this paper, a detailed analysis is provided, through finite element simulations, of the ways in which the sensor's geometrical parameters affect its performance. The geometrical parameters include the number of digits forming the interdigital electrodes and the ratio of digit width to their separation. In addition, the influence of the presence or absence of a metal backplane on the sample is analyzed. Further, the effects of sensor substrate thickness and material on signal strength are studied. The results of the analysis show that it is necessary to take into account a trade-off between the desired sensitivity and penetration depth when designing the sensor. Parametric equations are presented to assist the sensor designer or nondestructive evaluation specialist in optimizing the design of a capacitive sensor.

Integrated High Resolution Digital Color Light Sensor in 130 nm CMOS Technology

PubMed Central

Strle, Drago; Nahtigal, Uroš; Batistell, Graciele; Zhang, Vincent Chi; Ofner, Erwin; Fant, Andrea; Sturm, Johannes

2015-01-01

This article presents a color light detection system integrated in 130 nm CMOS technology. The sensors and corresponding electronics detect light in a CIE XYZ color luminosity space using on-chip integrated sensors without any additional process steps, high-resolution analog-to-digital converter, and dedicated DSP algorithm. The sensor consists of a set of laterally arranged integrated photodiodes that are partly covered by metal, where color separation between the photodiodes is achieved by lateral carrier diffusion together with wavelength-dependent absorption. A high resolution, hybrid, ∑∆ ADC converts each photo diode’s current into a 22-bit digital result, canceling the dark current of the photo diodes. The digital results are further processed by the DSP, which calculates normalized XYZ or RGB color and intensity parameters using linear transformations of the three photo diode responses by multiplication of the data with a transformation matrix, where the coefficients are extracted by training in combination with a pseudo-inverse operation and the least-mean square approximation. The sensor system detects the color light parameters with 22-bit accuracy, consumes less than 60 μA on average at 10 readings per second, and occupies approx. 0.8 mm2 of silicon area (including three photodiodes and the analog part of the ADC). The DSP is currently implemented on FPGA. PMID:26205275

Design and evaluation of a sensor fail-operational control system for a digitally controlled turbofan engine

NASA Technical Reports Server (NTRS)

Hrach, F. J.; Arpasi, D. J.; Bruton, W. M.

1975-01-01

A self-learning, sensor fail-operational, control system for the TF30-P-3 afterburning turbofan engine was designed and evaluated. The sensor fail-operational control system includes a digital computer program designed to operate in conjunction with the standard TF30-P-3 bill-of-materials control. Four engine measurements and two compressor face measurements are tested. If any engine measurements are found to have failed, they are replaced by values synthesized from computer-stored information. The control system was evaluated by using a realtime, nonlinear, hybrid computer engine simulation at sea level static condition, at a typical cruise condition, and at several extreme flight conditions. Results indicate that the addition of such a system can improve the reliability of an engine digital control system.

Evaluating video digitizer errors

NASA Astrophysics Data System (ADS)

Peterson, C.

2016-01-01

Analog output video cameras remain popular for recording meteor data. Although these cameras uniformly employ electronic detectors with fixed pixel arrays, the digitization process requires resampling the horizontal lines as they are output in order to reconstruct the pixel data, usually resulting in a new data array of different horizontal dimensions than the native sensor. Pixel timing is not provided by the camera, and must be reconstructed based on line sync information embedded in the analog video signal. Using a technique based on hot pixels, I present evidence that jitter, sync detection, and other timing errors introduce both position and intensity errors which are not present in cameras which internally digitize their sensors and output the digital data directly.

Forensics for flatbed scanners

NASA Astrophysics Data System (ADS)

Gloe, Thomas; Franz, Elke; Winkler, Antje

2007-02-01

Within this article, we investigate possibilities for identifying the origin of images acquired with flatbed scanners. A current method for the identification of digital cameras takes advantage of image sensor noise, strictly speaking, the spatial noise. Since flatbed scanners and digital cameras use similar technologies, the utilization of image sensor noise for identifying the origin of scanned images seems to be possible. As characterization of flatbed scanner noise, we considered array reference patterns and sensor line reference patterns. However, there are particularities of flatbed scanners which we expect to influence the identification. This was confirmed by extensive tests: Identification was possible to a certain degree, but less reliable than digital camera identification. In additional tests, we simulated the influence of flatfielding and down scaling as examples for such particularities of flatbed scanners on digital camera identification. One can conclude from the results achieved so far that identifying flatbed scanners is possible. However, since the analyzed methods are not able to determine the image origin in all cases, further investigations are necessary.

Traffic Monitor

NASA Technical Reports Server (NTRS)

1995-01-01

Intelligent Vision Systems, Inc. (InVision) needed image acquisition technology that was reliable in bad weather for its TDS-200 Traffic Detection System. InVision researchers used information from NASA Tech Briefs and assistance from Johnson Space Center to finish the system. The NASA technology used was developed for Earth-observing imaging satellites: charge coupled devices, in which silicon chips convert light directly into electronic or digital images. The TDS-200 consists of sensors mounted above traffic on poles or span wires, enabling two sensors to view an intersection; a "swing and sway" feature to compensate for movement of the sensors; a combination of electronic shutter and gain control; and sensor output to an image digital signal processor, still frame video and optionally live video.

Burr formation detector for fiber laser cutting based on a photodiode sensor system

NASA Astrophysics Data System (ADS)

Schleier, Max; Adelmann, Benedikt; Neumeier, Benedikt; Hellmann, Ralf

2017-11-01

We report a unique sensor system based on a InGaAs photodiode to detect the formation of burr during near infrared fiber laser cutting. The sensor approach encompasses the measurement of the thermal radiation form the process zone, optical filtering, digitalized sampling at 20 kHz, digital filtering using an elliptical band-pass filter 12th order and calculation of the standard deviation. We find a linear correlation between the deduced sensor signal and the generated burr height with this functionality being experimentally confirmed for laser cutting of mild and stainless steel of different thicknesses. The underlying mechanism of this transducer concept is attributed to the melt flow dynamics inside the cut kerf.

A fiber optic sensor for noncontact measurement of shaft speed, torque, and power

NASA Technical Reports Server (NTRS)

Madzsar, George C.

1990-01-01

A fiber optic sensor which enables noncontact measurement of the speed, torque and power of a rotating shaft was fabricated and tested. The sensor provides a direct measurement of shaft rotational speed and shaft angular twist, from which torque and power can be determined. Angles of twist between 0.005 and 10 degrees were measured. Sensor resolution is limited by the sampling rate of the analog to digital converter, while accuracy is dependent on the spot size of the focused beam on the shaft. Increasing the sampling rate improves measurement resolution, and decreasing the focused spot size increases accuracy. Digital processing allows for enhancement of an electronically or optically degraded signal.

A fiber optic sensor for noncontact measurement of shaft speed, torque and power

NASA Technical Reports Server (NTRS)

Madzsar, George C.

1990-01-01

A fiber optic sensor which enables noncontact measurement of the speed, torque and power of a rotating shaft was fabricated and tested. The sensor provides a direct measurement of shaft rotational speed and shaft angular twist, from which torque and power can be determined. Angles of twist between 0.005 and 10 degrees were measured. Sensor resolution is limited by the sampling rate of the analog to digital converter, while accuracy is dependent on the spot size of the focused beam on the shaft. Increasing the sampling rate improves measurement resolution, and decreasing the focused spot size increases accuracy. Digital processing allows for enhancement of an electronically or optically degraded signal.

Acquisition and analysis of accelerometer data

NASA Astrophysics Data System (ADS)

Verges, Keith R.

1990-08-01

Acceleration data reduction must be undertaken with a complete understanding of the physical process, the means by which the data are acquired, and finally, the calculations necessary to put the data into a meaningful format. Discussed here are the acceleration sensor requirements dictated by the measurements desired. Sensor noise, dynamic range, and linearity will be determined from the physical parameters of the experiment. The digitizer requirements are discussed. Here the system from sensor to digital storage medium will be integrated, and rules of thumb for experiment duration, filter response, and number of bits are explained. Data reduction techniques after storage are also discussed. Time domain operations including decimating, digital filtering, and averaging are covered, as well as frequency domain methods, including windowing and the difference between power and amplitude spectra, and simple noise determination via coherence analysis. Finally, an example experiment using the Teledyne Geotech Model 44000 Seismometer to measure from 1 Hz to 10(exp -6) Hz is discussed. The sensor, data acquisition system, and example spectra are presented.

Acquisition and analysis of accelerometer data

NASA Technical Reports Server (NTRS)

Verges, Keith R.

1990-01-01

Acceleration data reduction must be undertaken with a complete understanding of the physical process, the means by which the data are acquired, and finally, the calculations necessary to put the data into a meaningful format. Discussed here are the acceleration sensor requirements dictated by the measurements desired. Sensor noise, dynamic range, and linearity will be determined from the physical parameters of the experiment. The digitizer requirements are discussed. Here the system from sensor to digital storage medium will be integrated, and rules of thumb for experiment duration, filter response, and number of bits are explained. Data reduction techniques after storage are also discussed. Time domain operations including decimating, digital filtering, and averaging are covered, as well as frequency domain methods, including windowing and the difference between power and amplitude spectra, and simple noise determination via coherence analysis. Finally, an example experiment using the Teledyne Geotech Model 44000 Seismometer to measure from 1 Hz to 10(exp -6) Hz is discussed. The sensor, data acquisition system, and example spectra are presented.

A finite state machine read-out chip for integrated surface acoustic wave sensors

NASA Astrophysics Data System (ADS)

Rakshit, Sambarta; Iliadis, Agis A.

2015-01-01

A finite state machine based integrated sensor circuit suitable for the read-out module of a monolithically integrated SAW sensor on Si is reported. The primary sensor closed loop consists of a voltage controlled oscillator (VCO), a peak detecting comparator, a finite state machine (FSM), and a monolithically integrated SAW sensor device. The output of the system oscillates within a narrow voltage range that correlates with the SAW pass-band response. The period of oscillation is of the order of the SAW phase delay. We use timing information from the FSM to convert SAW phase delay to an on-chip 10 bit digital output operating on the principle of time to digital conversion (TDC). The control inputs of this digital conversion block are generated by a second finite state machine operating under a divided system clock. The average output varies with changes in SAW center frequency, thus tracking mass sensing events in real time. Based on measured VCO gain of 16 MHz/V our system will convert a 10 kHz SAW frequency shift to a corresponding mean voltage shift of 0.7 mV. A corresponding shift in phase delay is converted to a one or two bit shift in the TDC output code. The system can handle alternate SAW center frequencies and group delays simply by adjusting the VCO control and TDC delay control inputs. Because of frequency to voltage and phase to digital conversion, this topology does not require external frequency counter setups and is uniquely suitable for full monolithic integration of autonomous sensor systems and tags.

Low power sensor network for wireless condition monitoring

NASA Astrophysics Data System (ADS)

Richter, Ch.; Frankenstein, B.; Schubert, L.; Weihnacht, B.; Friedmann, H.; Ebert, C.

2009-03-01

For comprehensive fatigue tests and surveillance of large scale structures, a vibration monitoring system working in the Hz and sub Hz frequency range was realized and tested. The system is based on a wireless sensor network and focuses especially on the realization of a low power measurement, signal processing and communication. Regarding the development, we met the challenge of synchronizing the wireless connected sensor nodes with sufficient accuracy. The sensor nodes ware realized by compact, sensor near signal processing structures containing components for analog preprocessing of acoustic signals, their digitization, algorithms for data reduction and network communication. The core component is a digital micro controller which performs the basic algorithms necessary for the data acquisition synchronization and the filtering. As a first application, the system was installed in a rotor blade of a wind power turbine in order to monitor the Eigen modes over a longer period of time. Currently the sensor nodes are battery powered.

USB video image controller used in CMOS image sensor

NASA Astrophysics Data System (ADS)

Zhang, Wenxuan; Wang, Yuxia; Fan, Hong

2002-09-01

CMOS process is mainstream technique in VLSI, possesses high integration. SE402 is multifunction microcontroller, which integrates image data I/O ports, clock control, exposure control and digital signal processing into one chip. SE402 reduces the number of chips and PCB's room. The paper studies emphatically on USB video image controller used in CMOS image sensor and give the application on digital still camera.

Creating a transducer electronic datasheet using I2C serial EEPROM memory and PIC32-based microcontroller development board

NASA Astrophysics Data System (ADS)

Croitoru, Bogdan; Tulbure, Adrian; Abrudean, Mihail; Secara, Mihai

2015-02-01

The present paper describes a software method for creating / managing one type of Transducer Electronic Datasheet (TEDS) according to IEEE 1451.4 standard in order to develop a prototype of smart multi-sensor platform (with up to ten different analog sensors simultaneously connected) with Plug and Play capabilities over ETHERNET and Wi-Fi. In the experiments were used: one analog temperature sensor, one analog light sensor, one PIC32-based microcontroller development board with analog and digital I/O ports and other computing resources, one 24LC256 I2C (Inter Integrated Circuit standard) serial Electrically Erasable Programmable Read Only Memory (EEPROM) memory with 32KB available space and 3 bytes internal buffer for page writes (1 byte for data and 2 bytes for address). It was developed a prototype algorithm for writing and reading TEDS information to / from I2C EEPROM memories using the standard C language (up to ten different TEDS blocks coexisting in the same EEPROM device at once). The algorithm is able to write and read one type of TEDS: transducer information with standard TEDS content. A second software application, written in VB.NET platform, was developed in order to access the EEPROM sensor information from a computer through a serial interface (USB).

A highly accurate wireless digital sun sensor based on profile detecting and detector multiplexing technologies

NASA Astrophysics Data System (ADS)

Wei, Minsong; Xing, Fei; You, Zheng

2017-01-01

The advancing growth of micro- and nano-satellites requires miniaturized sun sensors which could be conveniently applied in the attitude determination subsystem. In this work, a profile detecting technology based high accurate wireless digital sun sensor was proposed, which could transform a two-dimensional image into two-linear profile output so that it can realize a high update rate under a very low power consumption. A multiple spots recovery approach with an asymmetric mask pattern design principle was introduced to fit the multiplexing image detector method for accuracy improvement of the sun sensor within a large Field of View (FOV). A FOV determination principle based on the concept of FOV region was also proposed to facilitate both sub-FOV analysis and the whole FOV determination. A RF MCU, together with solar cells, was utilized to achieve the wireless and self-powered functionality. The prototype of the sun sensor is approximately 10 times lower in size and weight compared with the conventional digital sun sensor (DSS). Test results indicated that the accuracy of the prototype was 0.01° within a cone FOV of 100°. Such an autonomous DSS could be equipped flexibly on a micro- or nano-satellite, especially for highly accurate remote sensing applications.

Portable Unit for Metabolic Analysis

NASA Technical Reports Server (NTRS)

Dietrich, Daniel L.; Pitch, Nancy D.; Lewis, Mark E.; Juergens, Jeffrey R.; Lichter, Michael J.; Stuk, Peter M.; Diedrick, Dale M.; Valentine, Russell W.; Pettegrew, Richard D.

2007-01-01

The Portable Unit for Metabolic Analysis (PUMA) is an instrument that measures several quantities indicative of human metabolic function. Specifically, this instrument makes time-resolved measurements of temperature, pressure, flow, and the partial pressures of oxygen and carbon dioxide in breath during both inhalation and exhalation. Portable instruments for measuring these quantities have been commercially available, but the response times of those instruments are too long to enable temporal resolution of phenomena on the time scales of human respiration cycles. In contrast, the response time of the PUMA is significantly shorter than characteristic times of human respiration phenomena, making it possible to analyze varying metabolic parameters, not only on sequential breath cycles but also at successive phases of inhalation and exhalation within the same breath cycle. In operation, the PUMA is positioned to sample breath near the subject s mouth. Commercial off-the-shelf sensors are used for three of the measurements: a miniature pressure transducer for pressure, a thermistor for temperature, and an ultrasonic sensor for flow. Sensors developed at Glenn Research Center are used for measuring the partial pressures of oxygen and carbon dioxide: The carbon dioxide sensor exploits the relatively strong absorption of infrared light by carbon dioxide. Light from an infrared source passes through the stream of inhaled or exhaled gas and is focused on an infrared- sensitive photodetector. The oxygen sensor exploits the effect of oxygen in quenching the fluorescence of ruthenium-doped organic molecules in a dye on the tip of an optical fiber. A blue laser diode is used to excite the fluorescence, and the optical fiber carries the fluorescent light to a photodiode, the temporal variation of the output of which bears a known relationship with the rate of quenching of fluorescence and, hence, with the partial pressure of oxygen. The outputs of the sensors are digitized, preprocessed by a small onboard computer, and then sent wirelessly to a desktop computer, where the collected data are analyzed and displayed. In addition to the raw data on temperature, pressure, flow, and mole fractions of oxygen and carbon dioxide, the display can include volumetric oxygen consumption, volumetric carbon dioxide production, respiratory equivalent ratio, and volumetric flow rate of exhaled gas.

Remote Sensing of Almond and Walnut Tree Canopy Temperatures Using an Inexpensive Infrared Sensor on a Small Unmanned Aerial Vehicle

NASA Astrophysics Data System (ADS)

Crawford, Kellen Ethan

Improving water use efficiency in agriculture will become increasingly important in the face of decreasing water resources and a growing population. Increasing water use efficiency, or water productivity, has been shown to greatly reduce irrigation water usage in many orchard crops with little to no impact on yield. In some specialty crops, improving water productivity can even lead to a higher value crop. Current irrigation practices depend largely on uniform applications of water over large fields with varying degrees of heterogeneity. As a result, much of the field receives more water than it needs. A system to monitor the needs of each plant or smaller groups of plants within the field would be helpful in distributing irrigation water according to each plant or group of plants' needs. Such a system would help conserve water resources. Stomatal conductance is a good indicator of plant water-based stress, as it is the main response a plant has to limit transpiration-related water losses. The difference between leaf temperature and air temperature, when adjusted for environmental conditions, can give a good indication of stomatal conductance. Recent efforts at UC Davis have employed a handheld sensor suite to measure leaf temperature and other environmental variables like wind speed, air temperature, and humidity in almond and walnut trees. Though effective, this method requires walking or driving through the orchard and measuring several leaves on a given tree, so it is impractical for large-scale monitoring. Satellite and aircraft can measure canopy temperatures remotely, but these applications typically do not have the spatial resolution for precise monitoring or the temporal resolution necessary for irrigation decisions, and they are too expensive and impractical for smaller-scale farms. A smaller unmanned aerial vehicle (UAV) could employ the same methods as satellite and larger aircraft-based systems, but relatively inexpensively and at a scale catered to the needs of a given field for more precise monitoring. The goal of this study was to explore the feasibility of using an inexpensive temperature sensor (Melexis MLX90614; NV Melexis SA, Rozendaalstraat 12, 8900 Ieper, Belgium) on a small UAV (Mikrokopter OktoXL; Hisystems GmbH Flachsmeerstrasse 2, 26802 Moormerland, Germany) to sense the canopy temperatures of almond and walnut trees. To accomplish this goal, we installed an infrared temperature sensor and a digital camera on a small UAV. The camera provided a spatial awareness of the IR temperature measurements which would otherwise require a very expensive thermal imager to obtain. The UAV was flown above almond and walnut trees recording images and temperatures, which were aligned temporally in post-processing. The pixels of each image were classified in to four classes: sunlit leaves, shaded leaves, sunlit soil, and shaded soil. Assuming that the measured temperature could be described as a weighted sum of each class in the field of view of the IR sensor, a linear system of equations was established to estimate the temperature of each class using at least several measurements of the same tree. Results indicated a good correlation between the temperatures estimated from the linear system of equations and the temperatures of those classes sampled on the ground immediately following each flight. With leaf temperatures ranging from about 12 to 40 degrees Celsius between 23 flights over two years, the linear solver was able to estimate the temperature of the sunlit and shaded leaves to within several degrees Celsius of the sampled temperature in most cases, with a coefficient of determination (r2 value) of 0.96 during the first year, and 0.73 during the second year. An additional study was undertaken to detect spatial temperature distribution within the orchard. Ground measurements were taken of every other tree in two walnut rows and one almond row using the handheld sensor, and the UAV was flown over those rows immediately following each ground sampling. An interpolated temperature map of the UAV's temperature measurements indicated a very similar temperature distribution as that measured with the handheld sensor, but the UAV was much faster and, in parts of the rows, it provided a higher spatial resolution than the handheld sensor.

40 CFR 63.2269 - What are my monitoring installation, operation, and maintenance requirements?

Code of Federal Regulations, 2010 CFR

2010-07-01

... temperature sensor in a position that provides a representative temperature. (2) Use a temperature sensor with... owners manual. Following the electronic calibration, you must conduct a temperature sensor validation check in which a second or redundant temperature sensor placed nearby the process temperature sensor...

40 CFR 63.2269 - What are my monitoring installation, operation, and maintenance requirements?

Code of Federal Regulations, 2011 CFR

2011-07-01

... temperature sensor in a position that provides a representative temperature. (2) Use a temperature sensor with... owners manual. Following the electronic calibration, you must conduct a temperature sensor validation check in which a second or redundant temperature sensor placed nearby the process temperature sensor...

Environment and health: Probes and sensors for environment digital control

NASA Astrophysics Data System (ADS)

Schettini, Chiara

2014-05-01

The idea of studying the environment using New Technologies (NT) came from a MIUR (Ministry of Education of the Italian Government) notice that allocated funds for the realization of innovative school science projects. The "Environment and Health" project uses probes and sensors for digital control of environment (water, air and soil). The working group was composed of 4 Science teachers from 'Liceo Statale G. Mazzini ', under the coordination of teacher Chiara Schettini. The Didactic Section of Naples City of Sciences helped the teachers in developing the project and it organized a refresher course for them on the utilization of digital control sensors. The project connects Environment and Technology because the study of the natural aspects and the analysis of the chemical-physical parameters give students and teachers skills for studying the environment based on the utilization of NT in computing data elaboration. During the practical project, samples of air, water and soil are gathered in different contexts. Sample analysis was done in the school's scientific laboratory with digitally controlled sensors. The data are elaborated with specific software and the results have been written in a booklet and in a computing database. During the first year, the project involved 6 school classes (age of the students 14—15 years), under the coordination of Science teachers. The project aims are: 1) making students more aware about environmental matters 2) achieving basic skills for evaluating air, water and soil quality. 3) achieving strong skills for the utilization of digitally controlled sensors. 4) achieving computing skills for elaborating and presenting data. The project aims to develop a large environmental conscience and the need of a ' good ' environment for defending our health. Moreover it would increase the importance of NT as an instrument of knowledge.

Fiber Laser methane sensor with the function of self-diagnose

NASA Astrophysics Data System (ADS)

Li, Yan-fang; Wei, Yu-bin; Shang, Ying; Wang, Chang; Liu, Tong-yu

2012-02-01

Using the technology of tunable diode laser absorption spectroscopy and the technology of micro-electronics, a fiber laser methane sensor based on the microprocessor C8051F410 is given. In this paper, we use the DFB Laser as the light source of the sensor. By tuning temperature and driver current of the DFB laser, we can scan the laser over the methane absorption line, Based on the Beer-Lambert law, through detect the variation of the light power before and after the absorption we realize the methane detection. It makes the real-time and online detection of methane concentration to be true, and it has the advantages just as high accuracy, immunity to other gases , long calibration cycle and so on. The sensor has the function of adaptive gain and self-diagnose. By introducing digital potentiometers, the gain of the photoelectric conversion operational amplifier can be controlled by the microprocessor according to the light power. When the gain and the conversion voltage achieve the set value, then we can consider the sensor in a fault status, and then the software will alarm us to check the status of the probe. So we improved the dependence and the stability of the measured results. At last we give some analysis on the sensor according the field application and according the present working, we have a look of our next work in the distance.

Shape memory polymer sensors for tracking cumulative environmental exposure

NASA Astrophysics Data System (ADS)

Snyder, Ryan; Rauscher, Michael; Vining, Ben; Havens, Ernie; Havens, Teresa; McFerran, Jace

2010-04-01

Cornerstone Research Group Inc. (CRG) has developed environmental exposure tracking (EET) sensors using shape memory polymers (SMP) to monitor the degradation of perishable items, such as munitions, foods and beverages, or medicines, by measuring the cumulative exposure to temperature and moisture. SMPs are polymers whose qualities have been altered to give them dynamic shape "memory" properties. Under thermal or moisture stimuli, the SMP exhibits a radical change from a rigid thermoset to a highly flexible, elastomeric state. The dynamic response of the SMP can be tailored to match the degradation profile of the perishable item. SMP-based EET sensors require no digital memory or internal power supply and provide the capability of inexpensive, long-term life cycle monitoring of thermal and moisture exposure over time. This technology was developed through Phase I and Phase II SBIR efforts with the Navy. The emphasis of current research centers on transitioning SMP materials from the lab bench to a production environment. Here, CRG presents the commercialization progress of thermally-activated EET sensors, focusing on fabrication scale-up, process refinements, and quality control. In addition, progress on the development of vapor pressure-responsive SMP (VPR-SMP) will be discussed.

Physical Intelligent Sensors

NASA Technical Reports Server (NTRS)

Bandhil, Pavan; Chitikeshi, Sanjeevi; Mahajan, Ajay; Figueroa, Fernando

2005-01-01

This paper proposes the development of intelligent sensors as part of an integrated systems approach, i.e. one treats the sensors as a complete system with its own sensing hardware (the traditional sensor), A/D converters, processing and storage capabilities, software drivers, self-assessment algorithms, communication protocols and evolutionary methodologies that allow them to get better with time. Under a project being undertaken at the NASA s Stennis Space Center, an integrated framework is being developed for the intelligent monitoring of smart elements. These smart elements can be sensors, actuators or other devices. The immediate application is the monitoring of the rocket test stands, but the technology should be generally applicable to the Integrated Systems Health Monitoring (ISHM) vision. This paper outlines progress made in the development of intelligent sensors by describing the work done till date on Physical Intelligent Sensors (PIS). The PIS discussed here consists of a thermocouple used to read temperature in an analog form which is then converted into digital values. A microprocessor collects the sensor readings and runs numerous embedded event detection routines on the collected data and if any event is detected, it is reported, stored and sent to a remote system through an Ethernet connection. Hence the output of the PIS is data coupled with confidence factor in the reliability of the data which leads to information on the health of the sensor at all times. All protocols are consistent with IEEE 1451.X standards. This work lays the foundation for the next generation of smart devices that have embedded intelligence for distributed decision making capabilities.

Pressure-Sensor Assembly Technique

NASA Technical Reports Server (NTRS)

Pruzan, Daniel A.

2003-01-01

Nielsen Engineering & Research (NEAR) recently developed an ultrathin data acquisition system for use in turbomachinery testing at NASA Glenn Research Center. This system integrates a microelectromechanical- systems- (MEMS-) based absolute pressure sensor [0 to 50 psia (0 to 345 kPa)], temperature sensor, signal-conditioning application-specific integrated circuit (ASIC), microprocessor, and digital memory into a package which is roughly 2.8 in. (7.1 cm) long by 0.75 in. (1.9 cm) wide. Each of these components is flip-chip attached to a thin, flexible circuit board and subsequently ground and polished to achieve a total system thickness of 0.006 in. (0.15 mm). Because this instrument is so thin, it can be quickly adhered to any surface of interest where data can be collected without disrupting the flow being investigated. One issue in the development of the ultrathin data acquisition system was how to attach the MEMS pressure sensor to the circuit board in a manner which allowed the sensor s diaphragm to communicate with the ambient fluid while providing enough support for the chip to survive the grinding and polishing operations. The technique, developed by NEAR and Jabil Technology Services Group (San Jose, CA), is described below. In the approach developed, the sensor is attached to the specially designed circuit board, see Figure 1, using a modified flip-chip technique. The circular diaphragm on the left side of the sensor is used to actively measure the ambient pressure, while the diaphragm on the right is used to compensate for changes in output due to temperature variations. The circuit board is fabricated with an access hole through it so that when the completed system is installed onto a wind tunnel model (chip side down), the active diaphragm is exposed to the environment. After the sensor is flip-chip attached to the circuit board, the die is underfilled to support the chip during the subsequent grinding and polishing operations. To prevent this underfill material from getting onto the sensor s diaphragms, the circuit board is fabricated with two 25- micrometer-tall polymer rings, sized so that the diaphragms fit inside the rings once the chip is attached.

A Low Power Digital Accumulation Technique for Digital-Domain CMOS TDI Image Sensor.

PubMed

Yu, Changwei; Nie, Kaiming; Xu, Jiangtao; Gao, Jing

2016-09-23

In this paper, an accumulation technique suitable for digital domain CMOS time delay integration (TDI) image sensors is proposed to reduce power consumption without degrading the rate of imaging. In terms of the slight variations of quantization codes among different pixel exposures towards the same object, the pixel array is divided into two groups: one is for coarse quantization of high bits only, and the other one is for fine quantization of low bits. Then, the complete quantization codes are composed of both results from the coarse-and-fine quantization. The equivalent operation comparably reduces the total required bit numbers of the quantization. In the 0.18 µm CMOS process, two versions of 16-stage digital domain CMOS TDI image sensor chains based on a 10-bit successive approximate register (SAR) analog-to-digital converter (ADC), with and without the proposed technique, are designed. The simulation results show that the average power consumption of slices of the two versions are 6 . 47 × 10 - 8 J/line and 7 . 4 × 10 - 8 J/line, respectively. Meanwhile, the linearity of the two versions are 99.74% and 99.99%, respectively.

A 256×256 low-light-level CMOS imaging sensor with digital CDS

NASA Astrophysics Data System (ADS)

Zou, Mei; Chen, Nan; Zhong, Shengyou; Li, Zhengfen; Zhang, Jicun; Yao, Li-bin

2016-10-01

In order to achieve high sensitivity for low-light-level CMOS image sensors (CIS), a capacitive transimpedance amplifier (CTIA) pixel circuit with a small integration capacitor is used. As the pixel and the column area are highly constrained, it is difficult to achieve analog correlated double sampling (CDS) to remove the noise for low-light-level CIS. So a digital CDS is adopted, which realizes the subtraction algorithm between the reset signal and pixel signal off-chip. The pixel reset noise and part of the column fixed-pattern noise (FPN) can be greatly reduced. A 256×256 CIS with CTIA array and digital CDS is implemented in the 0.35μm CMOS technology. The chip size is 7.7mm×6.75mm, and the pixel size is 15μm×15μm with a fill factor of 20.6%. The measured pixel noise is 24LSB with digital CDS in RMS value at dark condition, which shows 7.8× reduction compared to the image sensor without digital CDS. Running at 7fps, this low-light-level CIS can capture recognizable images with the illumination down to 0.1lux.

Note: Wide band amplifier for quartz tuning fork sensors with digitally controlled stray capacitance compensation.

PubMed

Peng, Ping; Hao, Lifeng; Ding, Ning; Jiao, Weicheng; Wang, Qi; Zhang, Jian; Wang, Rongguo

2015-11-01

We presented a preamplifier design for quartz tuning fork (QTF) sensors in which the stray capacitance is digitally compensated. In this design, the manually controlled variable capacitor is replaced by a pair of varicap diodes, whose capacitance could be accurately tuned by a bias voltage. A tuning circuit including a single side low power operational amplifier, a digital-to-analog converter, and a microprocessor is also described, and the tuning process can be conveniently carried out on a personal computer. For the design, the noise level was investigated experimentally.

Digital Suicide Prevention: Can Technology Become a Game-changer?

PubMed Central

Sahin, Ned; Kalali, Amir

2016-01-01

Suicide continues to be a leading cause of death and has been recognized as a significant public health issue. Rapid advances in data science can provide us with useful tools for suicide prevention, and help to dynamically assess suicide risk in quantitative data-driven ways. In this article, the authors highlight the most current international research in digital suicide prevention, including the use of machine learning, smartphone applications, and wearable sensor driven systems. The authors also discuss future opportunities for digital suicide prevention, and propose a novel Sensor-driven Mental State Assessment System. PMID:27800282

Fiber Optic Control System integration for advanced aircraft. Electro-optic and sensor fabrication, integration, and environmental testing for flight control systems

NASA Technical Reports Server (NTRS)

Seal, Daniel W.; Weaver, Thomas L.; Kessler, Bradley L.; Bedoya, Carlos A.; Mattes, Robert E.

1994-01-01

This report describes the design, development, and testing of passive fiber optic sensors and a multiplexing electro-optic architecture (EOA) for installation and flight test on a NASA-owned F-18 aircraft. This hardware was developed under the Fiber Optic Control Systems for Advanced Aircraft program, part of a multiyear NASA initiative to design, develop, and demonstrate through flight test 'fly-by-light' systems for application to advanced aircraft flight and propulsion control. This development included the design and production of 10 passive optical sensors and associated multiplexed EOA hardware based on wavelength division multiplexed (WDM) technology. A variety of sensor types (rotary position, linear position, temperature, and pressure) incorporating a broad range of sensor technologies (WDM analog, WDM digital, analog microbend, and fluorescent time rate of decay) were obtained from different manufacturers and functionally integrated with an independently designed EOA. The sensors were built for installation in a variety of aircraft locations, placing the sensors in a variety of harsh environments. The sensors and EOA were designed and built to have the resulting devices be as close as practical to a production system. The integrated system was delivered to NASA for flight testing on a NASA-owned F-18 aircraft. Development and integration testing of the system provided valuable information as to which sensor types were simplest to design and build for a military aircraft environment and which types were simplest to operate with a multiplexed EOA. Not all sensor types met the full range of performance and environmental requirements. EOA development problems provided information on directions to pursue in future fly-by-light flight control development programs. Lessons learned in the development of the EOA and sensor hardware are summarized.

Fiber Optic Control System integration for advanced aircraft. Electro-optic and sensor fabrication, integration, and environmental testing for flight control systems

NASA Astrophysics Data System (ADS)

Seal, Daniel W.; Weaver, Thomas L.; Kessler, Bradley L.; Bedoya, Carlos A.; Mattes, Robert E.

1994-11-01

This report describes the design, development, and testing of passive fiber optic sensors and a multiplexing electro-optic architecture (EOA) for installation and flight test on a NASA-owned F-18 aircraft. This hardware was developed under the Fiber Optic Control Systems for Advanced Aircraft program, part of a multiyear NASA initiative to design, develop, and demonstrate through flight test 'fly-by-light' systems for application to advanced aircraft flight and propulsion control. This development included the design and production of 10 passive optical sensors and associated multiplexed EOA hardware based on wavelength division multiplexed (WDM) technology. A variety of sensor types (rotary position, linear position, temperature, and pressure) incorporating a broad range of sensor technologies (WDM analog, WDM digital, analog microbend, and fluorescent time rate of decay) were obtained from different manufacturers and functionally integrated with an independently designed EOA. The sensors were built for installation in a variety of aircraft locations, placing the sensors in a variety of harsh environments. The sensors and EOA were designed and built to have the resulting devices be as close as practical to a production system. The integrated system was delivered to NASA for flight testing on a NASA-owned F-18 aircraft. Development and integration testing of the system provided valuable information as to which sensor types were simplest to design and build for a military aircraft environment and which types were simplest to operate with a multiplexed EOA. Not all sensor types met the full range of performance and environmental requirements. EOA development problems provided information on directions to pursue in future fly-by-light flight control development programs. Lessons learned in the development of the EOA and sensor hardware are summarized.

Shutter heating system of Antarctic bright star survey telescope

NASA Astrophysics Data System (ADS)

Chen, Jie; Dong, Shucheng; Jiang, Fengxin; Zhang, Hongfei; Wang, Jian

2016-07-01

A heat preservation system for mechanical shutter in Antarctic is introduced in the paper. The system consists of the heat preservation chamber, the host controller STM32F103C8T6 with peripheral circuit and the control algorithm. The whole design is carried out on the basis of the low temperature requirement, including the cavity structure and thermal insulation. The heat preservation chamber is used to keep the shutter warm and support the weight of the camera. Using PT100 as the temperature sensor, the signal processing circuit converts the temperature to the voltage which is then digitized by the 12 bit ADC in the STM32. The host controller transforms the voltage data into temperature, and through the tuning of the Fussy PID algorithm which controls the duty cycle of the MOSFET, the temperature control of chamber is realized. The System has been tested in the cryogenic environment for a long time, with characteristic of low temperature resistance, small volume, high accuracy of temperature control as well as remote control and detection.

Enhanced TCAS 2/CDTI traffic Sensor digital simulation model and program description

NASA Technical Reports Server (NTRS)

Goka, T.

1984-01-01

Digital simulation models of enhanced TCAS 2/CDTI traffic sensors are developed, based on actual or projected operational and performance characteristics. Two enhanced Traffic (or Threat) Alert and Collision Avoidance Systems are considered. A digital simulation program is developed in FORTRAN. The program contains an executive with a semireal time batch processing capability. The simulation program can be interfaced with other modules with a minimum requirement. Both the traffic sensor and CAS logic modules are validated by means of extensive simulation runs. Selected validation cases are discussed in detail, and capabilities and limitations of the actual and simulated systems are noted. The TCAS systems are not specifically intended for Cockpit Display of Traffic Information (CDTI) applications. These systems are sufficiently general to allow implementation of CDTI functions within the real systems' constraints.

An analog gamma correction scheme for high dynamic range CMOS logarithmic image sensors.

PubMed

Cao, Yuan; Pan, Xiaofang; Zhao, Xiaojin; Wu, Huisi

2014-12-15

In this paper, a novel analog gamma correction scheme with a logarithmic image sensor dedicated to minimize the quantization noise of the high dynamic applications is presented. The proposed implementation exploits a non-linear voltage-controlled-oscillator (VCO) based analog-to-digital converter (ADC) to perform the gamma correction during the analog-to-digital conversion. As a result, the quantization noise does not increase while the same high dynamic range of logarithmic image sensor is preserved. Moreover, by combining the gamma correction with the analog-to-digital conversion, the silicon area and overall power consumption can be greatly reduced. The proposed gamma correction scheme is validated by the reported simulation results and the experimental results measured for our designed test structure, which is fabricated with 0.35 μm standard complementary-metal-oxide-semiconductor (CMOS) process.

Radiometry simulation within the end-to-end simulation tool SENSOR

NASA Astrophysics Data System (ADS)

Wiest, Lorenz; Boerner, Anko

2001-02-01

12 An end-to-end simulation is a valuable tool for sensor system design, development, optimization, testing, and calibration. This contribution describes the radiometry module of the end-to-end simulation tool SENSOR. It features MODTRAN 4.0-based look up tables in conjunction with a cache-based multilinear interpolation algorithm to speed up radiometry calculations. It employs a linear reflectance parameterization to reduce look up table size, considers effects due to the topology of a digital elevation model (surface slope, sky view factor) and uses a reflectance class feature map to assign Lambertian and BRDF reflectance properties to the digital elevation model. The overall consistency of the radiometry part is demonstrated by good agreement between ATCOR 4-retrieved reflectance spectra of a simulated digital image cube and the original reflectance spectra used to simulate this image data cube.

An Analog Gamma Correction Scheme for High Dynamic Range CMOS Logarithmic Image Sensors

PubMed Central

Cao, Yuan; Pan, Xiaofang; Zhao, Xiaojin; Wu, Huisi

2014-01-01

In this paper, a novel analog gamma correction scheme with a logarithmic image sensor dedicated to minimize the quantization noise of the high dynamic applications is presented. The proposed implementation exploits a non-linear voltage-controlled-oscillator (VCO) based analog-to-digital converter (ADC) to perform the gamma correction during the analog-to-digital conversion. As a result, the quantization noise does not increase while the same high dynamic range of logarithmic image sensor is preserved. Moreover, by combining the gamma correction with the analog-to-digital conversion, the silicon area and overall power consumption can be greatly reduced. The proposed gamma correction scheme is validated by the reported simulation results and the experimental results measured for our designed test structure, which is fabricated with 0.35 μm standard complementary-metal-oxide-semiconductor (CMOS) process. PMID:25517692

Detection, Identification, Location, and Remote Sensing Using SAW RFID Sensor Tags

NASA Technical Reports Server (NTRS)

Barton, Richard J.; Kennedy, Timothy F.; Williams, Robert M.; Fink, Patrick W.; Ngo, Phong H.

2009-01-01

The Electromagnetic Systems Branch (EV4) of the Avionic Systems Division at NASA Johnson Space Center in Houston, TX is studying the utility of surface acoustic wave (SAW) radiofrequency identification (RFID) tags for multiple wireless applications including detection, identification, tracking, and remote sensing of objects on the lunar surface, monitoring of environmental test facilities, structural shape and health monitoring, and nondestructive test and evaluation of assets. For all of these applications, it is anticipated that the system utilized to interrogate the SAW RFID tags may need to operate at fairly long range and in the presence of considerable multipath and multiple-access interference. Towards that end, EV4 is developing a prototype SAW RFID wireless interrogation system for use in such environments called the Passive Adaptive RFID Sensor Equipment (PARSED) system. The system utilizes a digitally beam-formed planar receiving antenna array to extend range and provide direction-of-arrival information coupled with an approximate maximum-likelihood signal processing algorithm to provide near-optimal estimation of both range and temperature. The system is capable of forming a large number of beams within the field of view and resolving the information from several tags within each beam. The combination of both spatial and waveform discrimination provides the capability to track and monitor telemetry from a large number of objects appearing simultaneously within the field of view of the receiving array. In this paper, we will consider the application of the PARSEQ system to the problem of simultaneous detection, identification, localization, and temperature estimation for multiple objects. We will summarize the overall design of the PARSEQ system and present a detailed description of the design and performance of the signal detection and estimation algorithms incorporated in the system. The system is currently configured only to measure temperature (jointly with range and tag ID), but future versions will be revised to measure parameters other than temperature as SAW tags capable of interfacing with external sensors become available. It is anticipated that the estimation of arbitrary parameters measured using SAW-based sensors will be based on techniques very similar to the joint range and temperature estimation techniques described in this paper.

Integrated low power digital gyro control electronics

NASA Technical Reports Server (NTRS)

M'Closkey, Robert (Inventor); Grayver, Eugene (Inventor); Challoner, A. Dorian (Inventor); Hayworth, Ken J. (Inventor)

2005-01-01

Embodiments of the invention generally encompass a digital, application specific integrated circuit (ASIC) has been designed to perform excitation of a selected mode within a vibratory rate gyroscope, damping, or force-rebalance, of other modes within the sensor, and signal demodulation of the in-phase and quadrature components of the signal containing the angular rate information. The ASIC filters dedicated to each channel may be individually programmed to accommodate different rate sensor designs/technology or variations within the same class of sensors. The ASIC architecture employs a low-power design, making the ASIC, particularly suitable for use in power-sensitive applications.

Fiber-optic extrinsic Fabry-Perot interferometer sensors with three-wavelength digital phase demodulation.

PubMed

Schmidt, M; Fürstenau, N

1999-05-01

A three-wavelength-based passive quadrature digital phase-demodulation scheme has been developed for readout of fiber-optic extrinsic Fabry-Perot interferometer vibration, acoustic, and strain sensors. This scheme uses a superluminescent diode light source with interference filters in front of the photodiodes and real-time arctan calculation. Quasi-static strain and dynamic vibration sensing with up to an 80-kHz sampling rate is demonstrated. Periodic nonlinearities owing to dephasing with increasing fringe number are corrected for with a suitable algorithm, resulting in significant improvement of the linearity of the sensor characteristics.

Digital phase demodulation for low-coherence interferometry-based fiber-optic sensors

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

Liu, Y.; Strum, R.; Stiles, D.

In this paper, we describe a digital phase demodulation scheme for low-coherence interferometry-based fiber-optic sensors by employing a simple generation of phase-shifted signals at the interrogation interferometer. The scheme allows a real-time calibration process and offers capability of measuring large variations (up to the coherence of the light source) at the bandwidth that is only limited by the data acquisition system. Finally, the proposed phase demodulation method is analytically derived and its validity and performance are experimentally verified using fiber-optic Fabry–Perot sensors for measurement of strains and vibrations.

Digital phase demodulation for low-coherence interferometry-based fiber-optic sensors

DOE PAGES

Liu, Y.; Strum, R.; Stiles, D.; ...

2017-11-20

In this paper, we describe a digital phase demodulation scheme for low-coherence interferometry-based fiber-optic sensors by employing a simple generation of phase-shifted signals at the interrogation interferometer. The scheme allows a real-time calibration process and offers capability of measuring large variations (up to the coherence of the light source) at the bandwidth that is only limited by the data acquisition system. Finally, the proposed phase demodulation method is analytically derived and its validity and performance are experimentally verified using fiber-optic Fabry–Perot sensors for measurement of strains and vibrations.

UV radiation and CH4 gas detection with a single ZnO:Pd nanowire

NASA Astrophysics Data System (ADS)

Lupan, O.; Adelung, R.; Postica, V.; Ababii, N.; Chow, L.; Viana, B.; Pauporté, T.

2017-02-01

There is an increasing demand for sensors to monitor environmental levels of ultraviolet (UV) radiation and pollutant gases. In this work, an individual nanowire of Pd modified ZnO nanowire (ZnO:Pd NW) was integrated in a nanosensor device for efficient and fast detection of UV light and CH4 gas at room temperature. Crystalline ZnO:Pd nanowire/nanorod arrays were synthesized onto fluorine doped tin oxide (FTO) substrates by electrochemical deposition (ECD) at relative low-temperatures (90 °C) with different concentrations of PdCl2 in electrolyte solution and investigated by SEM and EDX. Nanodevices were fabricated using dual beam focused electron/ion beam (FIB/SEM) system and showed improved UV radiation response compared to pristine ZnO NW, reported previously by our group. The UV response was increased by one order in magnitude (≈ 11) for ZnO:Pd NW. Gas sensing measurements demonstrated a higher gas response and rapidity to methane (CH4 gas, 100 ppm) at room temperature, showing promising results for multifunctional applications. Also, due to miniature size and ultra-low power consumption of these sensors, it is possible to integrate them into portable devices easily, such as smartphones, digital clock, flame detection, missile lunching and other smart devices.

Digital Photography and Its Impact on Instruction.

ERIC Educational Resources Information Center

Lantz, Chris

Today the chemical processing of film is being replaced by a virtual digital darkroom. Digital image storage makes new levels of consistency possible because its nature is less volatile and more mutable than traditional photography. The potential of digital imaging is great, but issues of disk storage, computer speed, camera sensor resolution,…

A radiation hardened digital fluxgate magnetometer for space applications

NASA Astrophysics Data System (ADS)

Miles, D. M.; Bennest, J. R.; Mann, I. R.; Millling, D. K.

2013-09-01

Space-based measurements of Earth's magnetic field are required to understand the plasma processes responsible for energising particles in the Van Allen radiation belts and influencing space weather. This paper describes a prototype fluxgate magnetometer instrument developed for the proposed Canadian Space Agency's (CSA) Outer Radiation Belt Injection, Transport, Acceleration and Loss Satellite (ORBITALS) mission and which has applications in other space and suborbital applications. The magnetometer is designed to survive and operate in the harsh environment of Earth's radiation belts and measure low-frequency magnetic waves, the magnetic signatures of current systems, and the static background magnetic field. The new instrument offers improved science data compared to its predecessors through two key design changes: direct digitisation of the sensor and digital feedback from two cascaded pulse-width modulators combined with analog temperature compensation. These provide an increase in measurement bandwidth up to 450 Hz with the potential to extend to at least 1500 Hz. The instrument can resolve 8 pT on a 65 000 nT field with a magnetic noise of less than 10 pT/√Hz at 1 Hz. This performance is comparable with other recent digital fluxgates for space applications, most of which use some form of sigma-delta (ΣΔ) modulation for feedback and omit analog temperature compensation. The prototype instrument was successfully tested and calibrated at the Natural Resources Canada Geomagnetics Laboratory.

Estimation of absolute water surface temperature based on atmospherically corrected thermal infrared multispectral scanner digital data

NASA Technical Reports Server (NTRS)

Anderson, James E.

1986-01-01

Airborne remote sensing systems, as well as those on board Earth orbiting satellites, sample electromagnetic energy in discrete wavelength regions and convert the total energy sampled into data suitable for processing by digital computers. In general, however, the total amount of energy reaching a sensor system located at some distance from the target is composed not only of target related energy, but, in addition, contains a contribution originating from the atmosphere itself. Thus, some method must be devised for removing or at least minimizing the effects of the atmosphere. The LOWTRAN-6 Program was designed to estimate atmospheric transmittance and radiance for a given atmospheric path at moderate spectral resolution over an operational wavelength region from 0.25 to 28.5 microns. In order to compute the Thermal Infrared Multispectral Scanner (TIMS) digital values which were recorded in the absence of the atmosphere, the parameters derived from LOWTRAN-6 are used in a correction equation. The TIMS data were collected at 1:00 a.m. local time on November 21, 1983, over a recirculating cooling pond for a power plant in southeastern Mississippi. The TIMS data were analyzed before and after atmospheric corrections were applied using a band ratioing model to compute the absolute surface temperature of various points on the power plant cooling pond. The summarized results clearly demonstrate the desirability of applying atmospheric corrections.

Overview of Digital Forensics Algorithms in Dslr Cameras

NASA Astrophysics Data System (ADS)

Aminova, E.; Trapeznikov, I.; Priorov, A.

2017-05-01

The widespread usage of the mobile technologies and the improvement of the digital photo devices getting has led to more frequent cases of falsification of images including in the judicial practice. Consequently, the actual task for up-to-date digital image processing tools is the development of algorithms for determining the source and model of the DSLR (Digital Single Lens Reflex) camera and improve image formation algorithms. Most research in this area based on the mention that the extraction of unique sensor trace of DSLR camera could be possible on the certain stage of the imaging process into the camera. It is considered that the study focuses on the problem of determination of unique feature of DSLR cameras based on optical subsystem artifacts and sensor noises.

A data base of ASAS digital imagery. [Advanced Solid-state Array Spectroradiometer

NASA Technical Reports Server (NTRS)

Irons, James R.; Meeson, Blanche W.; Dabney, Philip W.; Kovalick, William M.; Graham, David W.; Hahn, Daniel S.

1992-01-01

The Advanced Solid-State Array Spectroradiometer (ASAS) is an airborne, off-nadir tilting, imaging spectroradiometer that acquires digital image data for 29 spectral bands in the visible and near-infrared. The sensor is used principally for studies of the bidirectional distribution of solar radiation scattered by terrestial surfaces. ASAS has acquired data for a number of terrestial ecosystem field experiments and investigators have received over 170 radiometrically corrected, multiangle, digital image data sets. A database of ASAS digital imagery has been established in the Pilot Land Data System (PLDS) at the NASA/Goddard Space Flight Center to provide access to these data by the scientific community. ASAS, its processed data, and the PLDS are described, together with recent improvements to the sensor system.

Advanced optical network architecture for integrated digital avionics

NASA Astrophysics Data System (ADS)

Morgan, D. Reed

1996-12-01

For the first time in the history of avionics, the network designer now has a choice in selecting the media that interconnects the sources and sinks of digital data on aircraft. Electrical designs are already giving way to photonics in application areas where the data rate times distance product is large or where special design requirements such as low weight or EMI considerations are critical. Future digital avionic architectures will increasingly favor the use of photonic interconnects as network data rates of one gigabit/second and higher are needed to support real-time operation of high-speed integrated digital processing. As the cost of optical network building blocks is reduced and as temperature-rugged laser sources are matured, metal interconnects will be forced to retreat to applications spanning shorter and shorter distances. Although the trend is already underway, the widespread use of digital optics will first occur at the system level, where gigabit/second, real-time interconnects between sensors, processors, mass memories and displays separated by a least of few meters will be required. The application of photonic interconnects for inter-printed wiring board signalling across the backplane will eventually find application for gigabit/second applications since signal degradation over copper traces occurs before one gigabit/second and 0.5 meters are reached. For the foreseeable future however, metal interconnects will continue to be used to interconnect devices on printed wiring boards since 5 gigabit/second signals can be sent over metal up to around 15 centimeters. Current-day applications of optical interconnects at the system level are described and a projection of how advanced optical interconnect technology will be driven by the use of high speed integrated digital processing on future aircraft is presented. The recommended advanced network for application in the 2010 time frame is a fiber-based system with a signalling speed of around 2-3 gigabits per second. This switch-based unified network will interconnect sensors, displays, mass memory and controls and displays to computer modules within the processing complex. The characteristics of required building blocks needed for the future are described. These building blocks include the fiber, an optical switch, a laser-based transceiver, blind-mate connectors and an optical backplane.

Virtual Sensors in a Web 2.0 Digital Watershed

NASA Astrophysics Data System (ADS)

Liu, Y.; Hill, D. J.; Marini, L.; Kooper, R.; Rodriguez, A.; Myers, J. D.

2008-12-01

The lack of rainfall data in many watersheds is one of the major barriers for modeling and studying many environmental and hydrological processes and supporting decision making. There are just not enough rain gages on the ground. To overcome this data scarcity issue, a Web 2.0 digital watershed is developed at NCSA(National Center for Supercomputing Applications), where users can point-and-click on a web-based google map interface and create new precipitation virtual sensors at any location within the same coverage region as a NEXRAD station. A set of scientific workflows are implemented to perform spatial, temporal and thematic transformations to the near-real-time NEXRAD Level II data. Such workflows can be triggered by the users' actions and generate either rainfall rate or rainfall accumulation streaming data at a user-specified time interval. We will discuss some underlying components of this digital watershed, which consists of a semantic content management middleware, a semantically enhanced streaming data toolkit, virtual sensor management functionality, and RESTful (REpresentational State Transfer) web service that can trigger the workflow execution. Such loosely coupled architecture presents a generic framework for constructing a Web 2.0 style digital watershed. An implementation of this architecture at the Upper Illinois Rive Basin will be presented. We will also discuss the implications of the virtual sensor concept for the broad environmental observatory community and how such concept will help us move towards a participatory digital watershed.

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.

The Design of a Single-Bit CMOS Image Sensor for Iris Recognition Applications

PubMed Central

Park, Keunyeol; Song, Minkyu

2018-01-01

This paper presents a single-bit CMOS image sensor (CIS) that uses a data processing technique with an edge detection block for simple iris segmentation. In order to recognize the iris image, the image sensor conventionally captures high-resolution image data in digital code, extracts the iris data, and then compares it with a reference image through a recognition algorithm. However, in this case, the frame rate decreases by the time required for digital signal conversion of multi-bit digital data through the analog-to-digital converter (ADC) in the CIS. In order to reduce the overall processing time as well as the power consumption, we propose a data processing technique with an exclusive OR (XOR) logic gate to obtain single-bit and edge detection image data instead of multi-bit image data through the ADC. In addition, we propose a logarithmic counter to efficiently measure single-bit image data that can be applied to the iris recognition algorithm. The effective area of the proposed single-bit image sensor (174 × 144 pixel) is 2.84 mm2 with a 0.18 μm 1-poly 4-metal CMOS image sensor process. The power consumption of the proposed single-bit CIS is 2.8 mW with a 3.3 V of supply voltage and 520 frame/s of the maximum frame rates. The error rate of the ADC is 0.24 least significant bit (LSB) on an 8-bit ADC basis at a 50 MHz sampling frequency. PMID:29495273

The Design of a Single-Bit CMOS Image Sensor for Iris Recognition Applications.

PubMed

Park, Keunyeol; Song, Minkyu; Kim, Soo Youn

2018-02-24

This paper presents a single-bit CMOS image sensor (CIS) that uses a data processing technique with an edge detection block for simple iris segmentation. In order to recognize the iris image, the image sensor conventionally captures high-resolution image data in digital code, extracts the iris data, and then compares it with a reference image through a recognition algorithm. However, in this case, the frame rate decreases by the time required for digital signal conversion of multi-bit digital data through the analog-to-digital converter (ADC) in the CIS. In order to reduce the overall processing time as well as the power consumption, we propose a data processing technique with an exclusive OR (XOR) logic gate to obtain single-bit and edge detection image data instead of multi-bit image data through the ADC. In addition, we propose a logarithmic counter to efficiently measure single-bit image data that can be applied to the iris recognition algorithm. The effective area of the proposed single-bit image sensor (174 × 144 pixel) is 2.84 mm² with a 0.18 μm 1-poly 4-metal CMOS image sensor process. The power consumption of the proposed single-bit CIS is 2.8 mW with a 3.3 V of supply voltage and 520 frame/s of the maximum frame rates. The error rate of the ADC is 0.24 least significant bit (LSB) on an 8-bit ADC basis at a 50 MHz sampling frequency.

AIRQino, a low-cost air quality mobile platform

NASA Astrophysics Data System (ADS)

Zaldei, Alessandro; Vagnoli, Carolina; Di Lonardo, Sara; Gioli, Beniamino; Gualtieri, Giovanni; Toscano, Piero; Martelli, Francesca; Matese, Alessandro

2015-04-01

Recent air quality regulations (Directive 2008/50/EC) enforce the transition from point-based monitoring networks to new tools that must be capable of mapping and forecasting air quality on the totality of land area, and therefore the totality of citizens. This implies new technologies such as models and additional indicative measurements, are needed in addition to accurate fixed air quality monitoring stations, that until now have been taken as reference by local administrators for the enforcement of various mitigation strategies. However, due to their sporadic spatial distribution, they cannot describe the highly resolved spatial pollutant variations within cities. Integrating additional indicative measurements may provide adequate information on the spatial distribution of the ambient air quality, also allowing for a reduction of the required minimum number of fixed sampling points, whose high cost and complex maintenance still remain a crucial concern for local administrators. New low-cost and small size sensors are becoming available, that could be employed in air quality monitoring including mobile applications. However, accurate assessment of their accuracy and performance both in controlled and real monitoring conditions is crucially needed. Quantifying sensor response is a significant challenge due to the sensitivity to ambient temperature and humidity and the cross-sensitivity to others pollutant species. This study reports the development of an Arduino compatible electronic board (AIRQino) which integrates a series of low-cost metal oxide and NDIR sensors for air quality monitoring, with sensors to measure air temperature, relative humidity, noise, solar radiation and vertical acceleration. A comparative assessment was made for CO2, CO, NO2, CH4, O3, VOCs concentrations, temperature and relative humidity. A controlled climatic chamber study (-80°C / +80°C) was performed to verify temperature and humidity interference using reference gas cylinders and high quality reference sensors. The AIRQino was installed on mobile vectors such as bikes, buses and trams in the cities of Firenze and Siracusa (Italy), that send data real-time to a Web portal. By integrating a microprocessor unit it is capable of directly updating calibration coefficients to provide corrected sensor output as digital string through RS232 serial port. Results from the lab tests and the 'real world' mobile applications are presented and discussed, to assess to what extent this sensor technology might be useful for the development of portable, compact, wireless and cost-effective system for air quality monitoring in urban areas at high spatio-temporal resolution.

CMOS Image Sensors: Electronic Camera On A Chip

NASA Technical Reports Server (NTRS)

Fossum, E. R.

1995-01-01

Recent advancements in CMOS image sensor technology are reviewed, including both passive pixel sensors and active pixel sensors. On- chip analog to digital converters and on-chip timing and control circuits permit realization of an electronic camera-on-a-chip. Highly miniaturized imaging systems based on CMOS image sensor technology are emerging as a competitor to charge-coupled devices for low cost uses.

Digital Health Intervention for Asthma: Patient-Reported Value and Usability.

PubMed

Merchant, Rajan; Inamdar, Rubina; Henderson, Kelly; Barrett, Meredith; Su, Jason G; Riley, Jesika; Van Sickle, David; Stempel, David

2018-06-04

Although digital health tools are increasingly recognized as effective in improving clinical outcomes such as asthma control and medication adherence, few studies have assessed patient experiences and perception of value. The aim of this study was to evaluate patient satisfaction, perception of usability and value, and desire to continue after 12 months of using a digital health intervention to support asthma management. Participants were enrolled in a randomized controlled study evaluating the impact of a digital health platform for asthma management. Participants used electronic inhaler sensors to track medication use and accessed their information in a digital health platform. Electronic surveys were administered to intervention arm participants aged 12 years and older after 12 months of use. The survey assessed asthma control, patient satisfaction with the sensor device, and perception of the usability and value of the digital health platform through closed-ended and open-ended questions. Logistic regression models were used to assess the impact of participants' characteristics on survey completion, satisfaction, and perception of value. Of the 207 intervention arm participants aged 12 years and older, 89 submitted survey responses (42.9% response rate). Of these 89 participants, 70 reported being very satisfied (79%, 70/89) or somewhat satisfied (20%, 18/89) with the inhaler sensor device. Moreover, 93% (83/89) expressed satisfaction with the reports, and 90% (80/89) found the information from the reports useful for learning about their asthma. In addition, 72% (64/89) of the participants reported that they were interested in continuing to use the sensor and platform beyond the study. There were no significant differences in satisfaction with the device or the platform across participants' characteristics, including device type, age, sex, insurance type, asthma control, or syncing history; however, participants with smartphones and longer participation were more likely to take the survey. Electronic sensors and a digital health platform were well received by participants who reported satisfaction and perceived value. These results were consistent across multiple participants' characteristics. These findings can add to a limited literature to keep improving digital health interventions and ensure the meaningful and enduring impact on patient outcomes. ©Rajan Merchant, Rubina Inamdar, Kelly Henderson, Meredith Barrett, Jason G Su, Jesika Riley, David Van Sickle, David Stempel. Originally published in JMIR Mhealth and Uhealth (http://mhealth.jmir.org), 04.06.2018.

Cryogenic microcalorimeter system for ultra-high resolution alpha-particle spectrometry

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

Rabin, Michael W; Hoover, Andrew S; Bacrania, Mnesh K

2009-01-01

Microcalorimeters have been shown to yield unsurpassed energy resolution for alpha spectrometry, up to 1.06 keV FWHM at 5.3 MeV. These detectors use a superconducting transition-edge sensor (TES) to measure the temperature change in an absorber from energy deposited by an interacting alpha particle. Our system has four independent detectors mounted inside a liquid nitrogen/liquid helium cryostat. An adiabatic demagnetization refrigerator (ADR) cools the detector stage to its operating temperature of 80 mK. Temperature regulation with {approx}15 uK peak-to-peak variation is achieved by PID control of the ADR. The detectors are voltage-biased, and the current signal is amplified by amore » commercial SQUID readout system and digitized for further analysis, This paper will discuss design and operation of our microcalorimeter alpha spectrometer, and will show recent results.« less

European roadmap on superconductive electronics - status and perspectives

NASA Astrophysics Data System (ADS)

Anders, S.; Blamire, M. G.; Buchholz, F.-Im.; Crété, D.-G.; Cristiano, R.; Febvre, P.; Fritzsch, L.; Herr, A.; Il'ichev, E.; Kohlmann, J.; Kunert, J.; Meyer, H.-G.; Niemeyer, J.; Ortlepp, T.; Rogalla, H.; Schurig, T.; Siegel, M.; Stolz, R.; Tarte, E.; ter Brake, H. J. M.; Toepfer, H.; Villegier, J.-C.; Zagoskin, A. M.; Zorin, A. B.

2010-12-01

Executive SummaryFor four decades semiconductor electronics has followed Moore’s law: with each generation of integration the circuit features became smaller, more complex and faster. This development is now reaching a wall so that smaller is no longer any faster. The clock rate has saturated at about 3-5 GHz and the parallel processor approach will soon reach its limit. The prime reason for the limitation the semiconductor electronics experiences is not the switching speed of the individual transistor, but its power dissipation and thus heat. Digital superconductive electronics is a circuit- and device-technology that is inherently faster at much less power dissipation than semiconductor electronics. It makes use of superconductors and Josephson junctions as circuit elements, which can provide extremely fast digital devices in a frequency range - dependent on the material - of hundreds of GHz: for example a flip-flop has been demonstrated that operated at 750 GHz. This digital technique is scalable and follows similar design rules as semiconductor devices. Its very low power dissipation of only 0.1 μW per gate at 100 GHz opens the possibility of three-dimensional integration. Circuits like microprocessors and analogue-to-digital converters for commercial and military applications have been demonstrated. In contrast to semiconductor circuits, the operation of superconducting circuits is based on naturally standardized digital pulses the area of which is exactly the flux quantum Φ0. The flux quantum is also the natural quantization unit for digital-to-analogue and analogue-to-digital converters. The latter application is so precise, that it is being used as voltage standard and that the physical unit ‘Volt’ is defined by means of this standard. Apart from its outstanding features for digital electronics, superconductive electronics provides also the most sensitive sensor for magnetic fields: the Superconducting Quantum Interference Device (SQUID). Amongst many other applications SQUIDs are used as sensors for magnetic heart and brain signals in medical applications, as sensor for geological surveying and food-processing and for non-destructive testing. As amplifiers of electrical signals, SQUIDs can nearly reach the theoretical limit given by Quantum Mechanics. A further important field of application is the detection of very weak signals by ‘transition-edge’ bolometers, superconducting nanowire single-photon detectors, and superconductive tunnel junctions. Their application as radiation detectors in a wide frequency range, from microwaves to X-rays is now standard. The very low losses of superconductors have led to commercial microwave filter designs that are now widely used in the USA in base stations for cellular phones and in military communication applications. The number of demonstrated applications is continuously increasing and there is no area in professional electronics, in which superconductive electronics cannot be applied and surpasses the performance of classical devices. Superconductive electronics has to be cooled to very low temperatures. Whereas this was a bottleneck in the past, cooling techniques have made a huge step forward in recent years: very compact systems with high reliability and a wide range of cooling power are available commercially, from microcoolers of match-box size with milli-Watt cooling power to high-reliability coolers of many Watts of cooling power for satellite applications. Superconductive electronics will not replace semiconductor electronics and similar room-temperature techniques in standard applications, but for those applications which require very high speed, low-power consumption, extreme sensitivity or extremely high precision, superconductive electronics is superior to all other available techniques. To strengthen the European competitiveness in superconductor electronics research projects have to be set-up in the following field: Ultra-sensitive sensing and imaging. Quantum measurement instrumentation. Advanced analogue-to-digital converters. Superconductive electronics technology.

Digital radiography: a survey of pediatric dentists.

PubMed

Russo, Julie M; Russo, James A; Guelmann, Marcio

2006-01-01

The purpose of this study was to: (1) determine the popularity of digital radiography among members of the American Academy of Pediatric Dentistry (AAPD); and (2) report the most common systems in use. An AAPD-approved, voluntary, and anonymous electronic survey was developed and sent to 923 board certified pediatric dentists. Years in practice and in-office x-ray technology (digital or conventional) were inquired about initially. If negative for the use of digital radiography, future consideration for converting to digital radiography was ascertained. For positive responses, more in-depth information was requested. Information on type of system (sensor or phosphor plate), user friendliness, diagnostic ability, patient's comfort, general costs, durability, and parental and overall satisfaction was collected. For most of the questions, a 5-point assessment scale was used. Opportunity for additional comments was provided upon survey completion. Data was analyzed using descriptive statistics. A 32% (296/923) response rate was obtained. Twenty-six percent of practitioners (78/296) implemented digital radiography in their practices, whereas 71% considered future acquisition. Similar distribution for sensor and phosphor plate users was found. Sensor technology was reported to produce faster images, but was less tolerable by young children due to size and thickness. Phosphor plates were considered more children friendly, less expensive, and less durable. Parental satisfaction was very high with great marketing value. Picture quality was comparable to conventional film. Overall, digital radiography users would recommend it to other pediatric dentists. Digital radiography is not yet popular among pediatric dentists. Cost reduction and technology advancement may enhance utilization.

Recent Instrumentation Developments in the Global Seismographic Network (GSN)

NASA Astrophysics Data System (ADS)

Hafner, K.; Davis, J. P.; Wilson, D.

2016-12-01

One of the challenges facing the GSN is continuing to provide robust, uniform high-quality, very broadband, high-dynamic range recordings of ground motion data as the original primary seismometers age. Recently the GSN has been upgrading all stations with the next generation of digital data acquisition systems (DASs), which has significantly increased the station data availability. In 2012, the Department of Energy received an additional $5.7M to support GSN refurbishment. The funds were transferred to the USGS via a 5-year interagency agreement and have been used for developing the next generation of very broadband (VBB) sensors. The USGS Albuquerque Seismic Laboratory (ASL) received the first prototype of a very broadband borehole sensor (Streckeisen STS-6A) in November 2015. Initial testing showed this prototype met all the required sensor specifications. Three pre-production sensors are scheduled to arrive by late August 2016. We will present the results of testing these devices, as well as an update on other recent VBB sensor developments (Trillium T360) and how they compare to the performance of the STS-1 and other available sensors. Recent work at ASL and the USArray Transportable Array has shown that installing sensors in shallow postholes up to 10 meters deep can lead to significant improvement in data quality. The GSN is investigating the potential of installing borehole sensors at some GSN stations where the STS-1 has shown significant susceptibility to pier tilt, temperature instability, or cultural noise. The GSN is also broadening the types of sensors deployed at GSN stations. After initial testing at ASL and UCSD's Pinyon Flat test site, the first infrasound sensor deployment will take place in Fall 2016. We will present the results of these tests and descriptions of the initial deployment.

Reliability of an infrared forehead skin thermometer for core temperature measurements.

PubMed

Kistemaker, J A; Den Hartog, E A; Daanen, H A M

2006-01-01

The SensorTouch thermometer performs an infrared measurement of the skin temperature above the Superficial Temporal Artery (STA). This study evaluates the validity and the accuracy of the SensorTouch thermometer. Two experiments were performed in which the body temperature was measured with a rectal sensor, with an oesophageal sensor and with the SensorTouch. After entering a warm chamber the SensorTouch underestimated the core temperature during the first 10 minutes. After that, the SensorTouch was not significantly different from the core temperature, with an average difference of 0.5 degrees C (SD 0.5 degrees C) in the first study and 0.3 degrees C (SD 0.2 degrees C) in the second study. The largest differences between the SensorTouch and the core temperature existed 15 minutes after the start of the exercise. During this period the SensorTouch was significantly higher than the core temperature. The SensorTouch did not provide reliable values of the body temperature during periods of increasing body temperature, but the SensorTouch might work under stable conditions.

Direct digital conversion detector technology

NASA Astrophysics Data System (ADS)

Mandl, William J.; Fedors, Richard

1995-06-01

Future imaging sensors for the aerospace and commercial video markets will depend on low cost, high speed analog-to-digital (A/D) conversion to efficiently process optical detector signals. Current A/D methods place a heavy burden on system resources, increase noise, and limit the throughput. This paper describes a unique method for incorporating A/D conversion right on the focal plane array. This concept is based on Sigma-Delta sampling, and makes optimum use of the active detector real estate. Combined with modern digital signal processors, such devices will significantly increase data rates off the focal plane. Early conversion to digital format will also decrease the signal susceptibility to noise, lowering the communications bit error rate. Computer modeling of this concept is described, along with results from several simulation runs. A potential application for direct digital conversion is also reviewed. Future uses for this technology could range from scientific instruments to remote sensors, telecommunications gear, medical diagnostic tools, and consumer products.

A custom multi-modal sensor suite and data analysis pipeline for aerial field phenotyping

NASA Astrophysics Data System (ADS)

Bartlett, Paul W.; Coblenz, Lauren; Sherwin, Gary; Stambler, Adam; van der Meer, Andries

2017-05-01

Our group has developed a custom, multi-modal sensor suite and data analysis pipeline to phenotype crops in the field using unpiloted aircraft systems (UAS). This approach to high-throughput field phenotyping is part of a research initiative intending to markedly accelerate the breeding process for refined energy sorghum varieties. To date, single rotor and multirotor helicopters, roughly 14 kg in total weight, are being employed to provide sensor coverage over multiple hectaresized fields in tens of minutes. The quick, autonomous operations allow for complete field coverage at consistent plant and lighting conditions, with low operating costs. The sensor suite collects data simultaneously from six sensors and registers it for fusion and analysis. High resolution color imagery targets color and geometric phenotypes, along with lidar measurements. Long-wave infrared imagery targets temperature phenomena and plant stress. Hyperspectral visible and near-infrared imagery targets phenotypes such as biomass and chlorophyll content, as well as novel, predictive spectral signatures. Onboard spectrometers and careful laboratory and in-field calibration techniques aim to increase the physical validity of the sensor data throughout and across growing seasons. Off-line processing of data creates basic products such as image maps and digital elevation models. Derived data products include phenotype charts, statistics, and trends. The outcome of this work is a set of commercially available phenotyping technologies, including sensor suites, a fully integrated phenotyping UAS, and data analysis software. Effort is also underway to transition these technologies to farm management users by way of streamlined, lower cost sensor packages and intuitive software interfaces.

Piezoresistive pressure sensor array for robotic skin

NASA Astrophysics Data System (ADS)

Mirza, Fahad; Sahasrabuddhe, Ritvij R.; Baptist, Joshua R.; Wijesundara, Muthu B. J.; Lee, Woo H.; Popa, Dan O.

2016-05-01

Robots are starting to transition from the confines of the manufacturing floor to homes, schools, hospitals, and highly dynamic environments. As, a result, it is impossible to foresee all the probable operational situations of robots, and preprogram the robot behavior in those situations. Among human-robot interaction technologies, haptic communication is an intuitive physical interaction method that can help define operational behaviors for robots cooperating with humans. Multimodal robotic skin with distributed sensors can help robots increase perception capabilities of their surrounding environments. Electro-Hydro-Dynamic (EHD) printing is a flexible multi-modal sensor fabrication method because of its direct printing capability of a wide range of materials onto substrates with non-uniform topographies. In past work we designed interdigitated comb electrodes as a sensing element and printed piezoresistive strain sensors using customized EHD printable PEDOT:PSS based inks. We formulated a PEDOT:PSS derivative ink, by mixing PEDOT:PSS and DMSO. Bending induced characterization tests of prototyped sensors showed high sensitivity and sufficient stability. In this paper, we describe SkinCells, robot skin sensor arrays integrated with electronic modules. 4x4 EHD-printed arrays of strain sensors was packaged onto Kapton sheets and silicone encapsulant and interconnected to a custom electronic module that consists of a microcontroller, Wheatstone bridge with adjustable digital potentiometer, multiplexer, and serial communication unit. Thus, SkinCell's electronics can be used for signal acquisition, conditioning, and networking between sensor modules. Several SkinCells were loaded with controlled pressure, temperature and humidity testing apparatuses, and testing results are reported in this paper.

A total patient monitoring system for point-of-care applications

NASA Astrophysics Data System (ADS)

Whitchurch, Ashwin K.; Abraham, Jose K.; Varadan, Vijay K.

2007-04-01

Traditionally, home care for chronically ill patients and the elderly requires periodic visits to the patient's home by doctors or healthcare personnel. During these visits, the visiting person usually records the patient's vital signs and takes decisions as to any change in treatment and address any issues that the patient may have. Patient monitoring systems have since changed this scenario by significantly reducing the number of home visits while not compromising on continuous monitoring. This paper describes the design and development of a patient monitoring systems capable of concurrent remote monitoring of 8 patient-worn sensors: Electroencephalogram (EEG), Electrocardiogram (ECG), temperature, airflow pressure, movement and chest expansion. These sensors provide vital signs useful for monitoring the health of chronically ill patients and alerts can be raised if certain specified signal levels fall above or below a preset threshold value. The data from all eight sensors are digitally transmitted to a PC or to a standalone network appliance which relays the data through an available internet connection to the remote monitoring client. Thus it provides a real-time rendering of the patient's health at a remote location.

Long-Term Outdoor Reliability Assessment of a Wireless Unit for Air-Quality Monitoring Based on Nanostructured Films Integrated on Micromachined Platforms

PubMed Central

Leccardi, Matteo; Decarli, Massimiliano; Lorenzelli, Leandro; Milani, Paolo; Mettala, Petteri; Orava, Risto; Barborini, Emanuele

2012-01-01

We have fabricated and tested in long-term field operating conditions a wireless unit for outdoor air quality monitoring. The unit is equipped with two multiparametric sensors, one miniaturized thermo-hygrometer, front-end analogical and digital electronics, and an IEEE 802.15.4 based module for wireless data transmission. Micromachined platforms were functionalized with nanoporous metal-oxides to obtain multiparametric sensors, hosting gas-sensitive, anemometric and temperature transducers. Nanoporous metal-oxide layer was directly deposited on gas sensing regions of micromachined platform batches by hard-mask patterned supersonic cluster beam deposition. An outdoor, roadside experiment was arranged in downtown Milan (Italy), where one wireless sensing unit was continuously operated side by side with standard gas chromatographic instrumentation for air quality measurements. By means of a router PC, data from sensing unit and other instrumentation were collected, merged, and sent to a remote data storage server, through an UMTS device. The whole-system robustness as well as sensor dataset characteristics were continuously characterized over a run-time period of 18 months. PMID:22969394

Analysis and Calibration of Sources of Electronic Error in PSD Sensor Response

PubMed Central

Rodríguez-Navarro, David; Lázaro-Galilea, José Luis; Bravo-Muñoz, Ignacio; Gardel-Vicente, Alfredo; Tsirigotis, Georgios

2016-01-01

In order to obtain very precise measurements of the position of agents located at a considerable distance using a sensor system based on position sensitive detectors (PSD), it is necessary to analyze and mitigate the factors that generate substantial errors in the system’s response. These sources of error can be divided into electronic and geometric factors. The former stem from the nature and construction of the PSD as well as the performance, tolerances and electronic response of the system, while the latter are related to the sensor’s optical system. Here, we focus solely on the electrical effects, since the study, analysis and correction of these are a prerequisite for subsequently addressing geometric errors. A simple calibration method is proposed, which considers PSD response, component tolerances, temperature variations, signal frequency used, signal to noise ratio (SNR), suboptimal operational amplifier parameters, and analog to digital converter (ADC) quantitation SNRQ, etc. Following an analysis of these effects and calibration of the sensor, it was possible to correct the errors, thus rendering the effects negligible, as reported in the results section. PMID:27136562

Low-Cost Embedded Oximeter

NASA Astrophysics Data System (ADS)

Laghrouche, M.; Haddab, S.; Lotmani, S.; Mekdoud, K.; Ameur, S.

2010-01-01

Nowadays, many medical devices have been developed for the purposes of diagnosing and treatment. Wearable sensors and systems have evolved to the point that they can be considered ready for clinical application. The use of wearable monitoring devices that allow continuous or intermittent monitoring of physiological signals is critical for the advancement of both the diagnosis as well as treatment of diseases. Patient vital sign monitoring within hospitals requires the use of noninvasive sensors that are hardwired to bedside monitors. This paper describes the initial bench testing of a wireless wearable pulse oximeter. Arterial oxygen saturation in the patient's blood signal was measured with an optical sensor, and then converted to digital data using a microcontroller system. The digital data were then sent to a receiver where it is in 433 MHz FM/FSK transmitter. At the receiver, the digital data were reconverted to analog signal to be monitored and recorded on the PC.

First experience with a wireless system incorporating physiologic assessments and direct confirmation of digital tablet ingestions in ambulatory patients with schizophrenia or bipolar disorder.

PubMed

Kane, John M; Perlis, Roy H; DiCarlo, Lorenzo A; Au-Yeung, Kityee; Duong, Jessie; Petrides, Georgios

2013-06-01

To characterize the feasibility and safety of a wireless networked system incorporating physiologic assessments and direct confirmation of digital tablet ingestions in ambulatory patients with schizophrenia or bipolar disorder. In this 4-week observational study conducted between May 2010 and May 2011 at 2 US academic clinical study sites, 12 adults with bipolar disorder and 16 adults with schizophrenia (all diagnosed according to DSM-IV criteria) utilized a digital health feedback system (DHFS). All subjects were on a stable regimen of oral medication. The DHFS utilized a digital tablet, consisting of an ingestion sensor that was embedded in a tablet containing nonpharmacologic excipients, which subjects coingested with their regularly prescribed medication. The formulation of this digital tablet allowed ingestion sensor separation and activation by stomach fluids after ingestion, followed by communication of a unique identifying signal from the ingestion sensor to an adhesive sensor worn on the torso, which automatically logged the date and time of each digital tablet ingestion. The wearable sensor also collected physiologic measures including activity and heart rate. The primary study objective was to compare the accuracy of DHFS in confirming digital tablet ingestion versus a method of directly observed ingestion; secondary aims included characterization of adherence and physiologic measures longitudinally in these cohorts. 27 of 28 subjects (96%) completed the study. The mean adherence rate was 74% (95% CI, 64%-86%), and 67% (95% CI, 55%-79%) of doses were taken within 2 hours of the prescribed dosing time. Activity consisted of 847 to 15,930 steps daily, and sleep duration ranged from 3.2 to 15.2 hours daily. For individual subjects, mean sleep disruption, defined as the amount of brief arousals and postural changes during sleep events (eg, subject sitting up during the night), was as low as 5% and as high as 43% for the entire study period. The most common adverse event was minor skin irritation that occurred at the site of the wearable sensor in 5 subjects (18%), which did not lead to early discontinuation. No adverse events occurred due to the ingestion sensor. No subjects developed worsening of psychosis attributable to use of the DHFS. Of the 27 subjects who completed the study, 19 (70%) found the DHFS concept easy to understand, 21 (78%) said they would like to receive reminders on their cell phone if they forgot to take their medications, and 24 (89%) thought the DHFS could be useful to them. The DHFS provided a novel means of confirming medication ingestion and tracking selected physiologic parameters, and it was generally well tolerated by patients. ClinicalTrials.gov identifier: NCT01804257. © Copyright 2013 Physicians Postgraduate Press, Inc.

Epidermal photonic devices for quantitative imaging of temperature and thermal transport characteristics of the skin

NASA Astrophysics Data System (ADS)

Gao, Li; Zhang, Yihui; Malyarchuk, Viktor; Jia, Lin; Jang, Kyung-In; Chad Webb, R.; Fu, Haoran; Shi, Yan; Zhou, Guoyan; Shi, Luke; Shah, Deesha; Huang, Xian; Xu, Baoxing; Yu, Cunjiang; Huang, Yonggang; Rogers, John A.

2014-09-01

Characterization of temperature and thermal transport properties of the skin can yield important information of relevance to both clinical medicine and basic research in skin physiology. Here we introduce an ultrathin, compliant skin-like, or ‘epidermal’, photonic device that combines colorimetric temperature indicators with wireless stretchable electronics for thermal measurements when softly laminated on the skin surface. The sensors exploit thermochromic liquid crystals patterned into large-scale, pixelated arrays on thin elastomeric substrates; the electronics provide means for controlled, local heating by radio frequency signals. Algorithms for extracting patterns of colour recorded from these devices with a digital camera and computational tools for relating the results to underlying thermal processes near the skin surface lend quantitative value to the resulting data. Application examples include non-invasive spatial mapping of skin temperature with milli-Kelvin precision (±50 mK) and sub-millimetre spatial resolution. Demonstrations in reactive hyperaemia assessments of blood flow and hydration analysis establish relevance to cardiovascular health and skin care, respectively.

Epidermal photonic devices for quantitative imaging of temperature and thermal transport characteristics of the skin.

PubMed

Gao, Li; Zhang, Yihui; Malyarchuk, Viktor; Jia, Lin; Jang, Kyung-In; Webb, R Chad; Fu, Haoran; Shi, Yan; Zhou, Guoyan; Shi, Luke; Shah, Deesha; Huang, Xian; Xu, Baoxing; Yu, Cunjiang; Huang, Yonggang; Rogers, John A

2014-09-19

Characterization of temperature and thermal transport properties of the skin can yield important information of relevance to both clinical medicine and basic research in skin physiology. Here we introduce an ultrathin, compliant skin-like, or 'epidermal', photonic device that combines colorimetric temperature indicators with wireless stretchable electronics for thermal measurements when softly laminated on the skin surface. The sensors exploit thermochromic liquid crystals patterned into large-scale, pixelated arrays on thin elastomeric substrates; the electronics provide means for controlled, local heating by radio frequency signals. Algorithms for extracting patterns of colour recorded from these devices with a digital camera and computational tools for relating the results to underlying thermal processes near the skin surface lend quantitative value to the resulting data. Application examples include non-invasive spatial mapping of skin temperature with milli-Kelvin precision (±50 mK) and sub-millimetre spatial resolution. Demonstrations in reactive hyperaemia assessments of blood flow and hydration analysis establish relevance to cardiovascular health and skin care, respectively.

Optimization and thermal ASE noise characterization of an all-fibre Sagnac interferometer via LAN for sensing applications

NASA Astrophysics Data System (ADS)

Sierra-Calderon, A.; Rodriguez-Novelo, J. C.; Gamez-Aviles, E.; May-Alarcon, M.; Toral-Cruz, H.; Alvarez-Chavez, J. A.

2016-09-01

The spectral noise characteristic and relative intensity noise of an all fibre Sagnac interferometer system consisting of a 980nm pump source at 130mW maximum output power, a 980/1550nm wavelength division multiplexer, a 10m-piece of Erbium-doped fibre, a fibre Bragg grating (FBG) centered at 1.548um, an optical circulator at 1550nm and a 50/50 fibre coupler, were measured with an optical spectrum analyzer (OSA) for fine tuning for a range of temperature between 5 and 180 degrees Celsius in step of 1 degree Celsius. At the probing end, a high-bi piece of fibre and a Peltier were employed for temperature variation of the system. Spectral and temperature response of the noise reduction due to temperature variation was performed remotely using and Arduino micro-controller and a DS18B20 digital sensor, into a local area network. Full optical and thermal characterization of the system will be included in the presentation.

A Passive Radio-Frequency Identification (RFID) Gas Sensor With Self-Correction Against Fluctuations of Ambient Temperature

PubMed Central

Potyrailo, Radislav A.; Surman, Cheryl

2013-01-01

Uncontrolled fluctuations of ambient temperature in the field typically greatly reduce accuracy of gas sensors. In this study, we developed an approach for the self-correction against fluctuations of ambient temperature of individual gas and vapor sensors. The main innovation of our work is in the temperature correction which is accomplished without the need for a separate uncoated reference sensor or a separate temperature sensor. Our sensors are resonant inductor-capacitor-resistor (LCR) transducers coated with sensing materials and operated as multivariable passive (battery-free) radio-frequency identification (RFID) sensors. Using our developed approach, we performed quantitation of an exemplary vapor over the temperature range from 25 to 40 °C. This technical solution will be attractive in numerous applications where temperature stabilization of a gas sensor or addition of auxiliary temperature or uncoated reference sensors is prohibitive. PMID:23956496

Digital Architecture for a Trace Gas Sensor Platform

NASA Technical Reports Server (NTRS)

Gonzales, Paula; Casias, Miguel; Vakhtin, Andrei; Pilgrim, Jeffrey

2012-01-01

A digital architecture has been implemented for a trace gas sensor platform, as a companion to standard analog control electronics, which accommodates optical absorption whose fractional absorbance equivalent would result in excess error if assumed to be linear. In cases where the absorption (1-transmission) is not equivalent to the fractional absorbance within a few percent error, it is necessary to accommodate the actual measured absorption while reporting the measured concentration of a target analyte with reasonable accuracy. This requires incorporation of programmable intelligence into the sensor platform so that flexible interpretation of the acquired data may be accomplished. Several different digital component architectures were tested and implemented. Commercial off-the-shelf digital electronics including data acquisition cards (DAQs), complex programmable logic devices (CPLDs), field-programmable gate arrays (FPGAs), and microcontrollers have been used to achieve the desired outcome. The most completely integrated architecture achieved during the project used the CPLD along with a microcontroller. The CPLD provides the initial digital demodulation of the raw sensor signal, and then communicates over a parallel communications interface with a microcontroller. The microcontroller analyzes the digital signal from the CPLD, and applies a non-linear correction obtained through extensive data analysis at the various relevant EVA operating pressures. The microcontroller then presents the quantitatively accurate carbon dioxide partial pressure regardless of optical density. This technique could extend the linear dynamic range of typical absorption spectrometers, particularly those whose low end noise equivalent absorbance is below one-part-in-100,000. In the EVA application, it allows introduction of a path-length-enhancing architecture whose optical interference effects are well understood and quantified without sacrificing the dynamic range that allows quantitative detection at the higher carbon dioxide partial pressures. The digital components are compact and allow reasonably complete integration with separately developed analog control electronics without sacrificing size, mass, or power draw.

WGM Temperature Tracker

NASA Technical Reports Server (NTRS)

Strekalov, Dmitry V.

2012-01-01

This software implements digital control of a WGM (whispering-gallerymode) resonator temperature based on the dual-mode approach. It comprises one acquisition (dual-channel) and three control modules. The interaction of the proportional-integral loops is designed in the original way, preventing the loops from fighting. The data processing is organized in parallel with the acquisition, which allows the computational overhead time to be suppressed or often completely avoided. WGM resonators potentially provide excellent optical references for metrology, clocks, spectroscopy, and other applications. However, extremely accurate (below micro-Kelvin) temperature stabilization is required. This software allows one specifically advantageous method of such stabilization to be implemented, which is immune to a variety of effects that mask the temperature variation. WGM Temperature Tracker 2.3 (see figure) is a LabVIEW code developed for dual-mode temperature stabilization of WGM resonators. It has allowed for the temperature stabilization at the level of 200 nK with one-second integration time, and 6 nK with 10,000-second integration time, with the above room-temperature set point. This software, in conjunction with the appropriate hardware, can be used as a noncryogenic temperature sensor/ controller with sub-micro-Kelvin sensitivity, which at the time of this reporting considerably outperforms the state of the art.

CMOS image sensor for detection of interferon gamma protein interaction as a point-of-care approach.

PubMed

Marimuthu, Mohana; Kandasamy, Karthikeyan; Ahn, Chang Geun; Sung, Gun Yong; Kim, Min-Gon; Kim, Sanghyo

2011-09-01

Complementary metal oxide semiconductor (CMOS)-based image sensors have received increased attention owing to the possibility of incorporating them into portable diagnostic devices. The present research examined the efficiency and sensitivity of a CMOS image sensor for the detection of antigen-antibody interactions involving interferon gamma protein without the aid of expensive instruments. The highest detection sensitivity of about 1 fg/ml primary antibody was achieved simply by a transmission mechanism. When photons are prevented from hitting the sensor surface, a reduction in digital output occurs in which the number of photons hitting the sensor surface is approximately proportional to the digital number. Nanoscale variation in substrate thickness after protein binding can be detected with high sensitivity by the CMOS image sensor. Therefore, this technique can be easily applied to smartphones or any clinical diagnostic devices for the detection of several biological entities, with high impact on the development of point-of-care applications.

Digitally Programmable Analogue Circuits for Sensor Conditioning Systems

PubMed Central

Zatorre, Guillermo; Medrano, Nicolás; Sanz, María Teresa; Aldea, Concepción; Calvo, Belén; Celma, Santiago

2009-01-01

This work presents two current-mode integrated circuits designed for sensor signal preprocessing in embedded systems. The proposed circuits have been designed to provide good signal transfer and fulfill their function, while minimizing the load effects due to building complex conditioning architectures. The processing architecture based on the proposed building blocks can be reconfigured through digital programmability. Thus, sensor useful range can be expanded, changes in the sensor operation can be compensated for and furthermore, undesirable effects such as device mismatching and undesired physical magnitudes sensor sensibilities are reduced. The circuits were integrated using a 0.35 μm standard CMOS process. Experimental measurements, load effects and a study of two different tuning strategies are presented. From these results, system performance is tested in an application which entails extending the linear range of a magneto-resistive sensor. Circuit area, average power consumption and programmability features allow these circuits to be included in embedded sensing systems as a part of the analogue conditioning components. PMID:22412331

SPADnet: a fully digital, scalable, and networked photonic component for time-of-flight PET applications

NASA Astrophysics Data System (ADS)

Bruschini, Claudio; Charbon, Edoardo; Veerappan, Chockalingam; Braga, Leo H. C.; Massari, Nicola; Perenzoni, Matteo; Gasparini, Leonardo; Stoppa, David; Walker, Richard; Erdogan, Ahmet; Henderson, Robert K.; East, Steve; Grant, Lindsay; Játékos, Balázs; Ujhelyi, Ferenc; Erdei, Gábor; Lörincz, Emöke; André, Luc; Maingault, Laurent; Jacolin, David; Verger, L.; Gros d'Aillon, Eric; Major, Peter; Papp, Zoltan; Nemeth, Gabor

2014-05-01

The SPADnet FP7 European project is aimed at a new generation of fully digital, scalable and networked photonic components to enable large area image sensors, with primary target gamma-ray and coincidence detection in (Time-of- Flight) Positron Emission Tomography (PET). SPADnet relies on standard CMOS technology, therefore allowing for MRI compatibility. SPADnet innovates in several areas of PET systems, from optical coupling to single-photon sensor architectures, from intelligent ring networks to reconstruction algorithms. It is built around a natively digital, intelligent SPAD (Single-Photon Avalanche Diode)-based sensor device which comprises an array of 8×16 pixels, each composed of 4 mini-SiPMs with in situ time-to-digital conversion, a multi-ring network to filter, carry, and process data produced by the sensors at 2Gbps, and a 130nm CMOS process enabling mass-production of photonic modules that are optically interfaced to scintillator crystals. A few tens of sensor devices are tightly abutted on a single PCB to form a so-called sensor tile, thanks to TSV (Through Silicon Via) connections to their backside (replacing conventional wire bonding). The sensor tile is in turn interfaced to an FPGA-based PCB on its back. The resulting photonic module acts as an autonomous sensing and computing unit, individually detecting gamma photons as well as thermal and Compton events. It determines in real time basic information for each scintillation event, such as exact time of arrival, position and energy, and communicates it to its peers in the field of view. Coincidence detection does therefore occur directly in the ring itself, in a differed and distributed manner to ensure scalability. The selected true coincidence events are then collected by a snooper module, from which they are transferred to an external reconstruction computer using Gigabit Ethernet.

Analysis, design, fabrication and testing of an optical tip clearance sensor. [turbocompressor blade tips

NASA Technical Reports Server (NTRS)

Poppel, G. L.; Marple, D. T. F.; Kingsley, J. D.

1981-01-01

Analyses and the design, fabrication, and testing of an optical tip clearance sensor with intended application in aircraft propulsion control systems are reported. The design of a sensor test rig, evaluation of optical sensor components at elevated temperatures, sensor design principles, sensor test results at room temperature, and estimations of sensor accuracy at temperatures of an aircraft engine environment are discussed. Room temperature testing indicated possible measurement accuracies of less than 12.7 microns (0.5 mils). Ways to improve performance at engine operating temperatures are recommended. The potential of this tip clearance sensor is assessed.

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.

Toward a digital camera to rival the human eye

NASA Astrophysics Data System (ADS)

Skorka, Orit; Joseph, Dileepan

2011-07-01

All things considered, electronic imaging systems do not rival the human visual system despite notable progress over 40 years since the invention of the CCD. This work presents a method that allows design engineers to evaluate the performance gap between a digital camera and the human eye. The method identifies limiting factors of the electronic systems by benchmarking against the human system. It considers power consumption, visual field, spatial resolution, temporal resolution, and properties related to signal and noise power. A figure of merit is defined as the performance gap of the weakest parameter. Experimental work done with observers and cadavers is reviewed to assess the parameters of the human eye, and assessment techniques are also covered for digital cameras. The method is applied to 24 modern image sensors of various types, where an ideal lens is assumed to complete a digital camera. Results indicate that dynamic range and dark limit are the most limiting factors. The substantial functional gap, from 1.6 to 4.5 orders of magnitude, between the human eye and digital cameras may arise from architectural differences between the human retina, arranged in a multiple-layer structure, and image sensors, mostly fabricated in planar technologies. Functionality of image sensors may be significantly improved by exploiting technologies that allow vertical stacking of active tiers.

Automatic registration of fused lidar/digital imagery (texel images) for three-dimensional image creation

NASA Astrophysics Data System (ADS)

Budge, Scott E.; Badamikar, Neeraj S.; Xie, Xuan

2015-03-01

Several photogrammetry-based methods have been proposed that the derive three-dimensional (3-D) information from digital images from different perspectives, and lidar-based methods have been proposed that merge lidar point clouds and texture the merged point clouds with digital imagery. Image registration alone has difficulty with smooth regions with low contrast, whereas point cloud merging alone has difficulty with outliers and a lack of proper convergence in the merging process. This paper presents a method to create 3-D images that uses the unique properties of texel images (pixel-fused lidar and digital imagery) to improve the quality and robustness of fused 3-D images. The proposed method uses both image processing and point-cloud merging to combine texel images in an iterative technique. Since the digital image pixels and the lidar 3-D points are fused at the sensor level, more accurate 3-D images are generated because registration of image data automatically improves the merging of the point clouds, and vice versa. Examples illustrate the value of this method over other methods. The proposed method also includes modifications for the situation where an estimate of position and attitude of the sensor is known, when obtained from low-cost global positioning systems and inertial measurement units sensors.

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

Infection control procedures used in conjunction with computed dental radiography.

PubMed

Hubar, J S; Gardiner, D M

2000-10-01

Infection control guidelines for dental radiography have been modified since 1986, when the American Dental Association and the Centers for Disease Control and Prevention supported the concept of "universal blood and body fluid precautions." With the introduction of computed digital radiography, hardware manufacturers recommend that alternative infection control techniques are necessary to prevent potential damage to the digital x-ray sensors placed inside the patient's mouth. Thirty first-year dental hygiene students were asked to insert and remove a Schick CDR number 2 size intraoral digital x-ray sensor into modified Rinn XCP bitewing bite blocks and a modified Rinn Snap-a-ray five times with each of the recommended infection control covers. Reduced rates of cross contamination are possible if the plastic barrier envelope has an additional latex finger cot stretched over it and the x-ray sensor. Sole usage of a latex finger cot will result in a reduced incidence of contamination, but still not to acceptable levels. However, a plastic barrier envelope placed over the x-ray sensor and over the modified XCP bite block together or a covered sensor in a Snap-a-ray under normal conditions does not result in a perforation and is least likely to result in cross contamination.

Performance evaluation of TDT soil water content and watermark soil water potential sensors

USDA-ARS?s Scientific Manuscript database

This study evaluated the performance of digitized Time Domain Transmissometry (TDT) soil water content sensors (Acclima, Inc., Meridian, ID) and resistance-based soil water potential sensors (Watermark 200, Irrometer Company, Inc., Riverside, CA) in two soils. The evaluation was performed by compar...

Data center thermal management

DOEpatents

Hamann, Hendrik F.; Li, Hongfei

2016-02-09

Historical high-spatial-resolution temperature data and dynamic temperature sensor measurement data may be used to predict temperature. A first formulation may be derived based on the historical high-spatial-resolution temperature data for determining a temperature at any point in 3-dimensional space. The dynamic temperature sensor measurement data may be calibrated based on the historical high-spatial-resolution temperature data at a corresponding historical time. Sensor temperature data at a plurality of sensor locations may be predicted for a future time based on the calibrated dynamic temperature sensor measurement data. A three-dimensional temperature spatial distribution associated with the future time may be generated based on the forecasted sensor temperature data and the first formulation. The three-dimensional temperature spatial distribution associated with the future time may be projected to a two-dimensional temperature distribution, and temperature in the future time for a selected space location may be forecasted dynamically based on said two-dimensional temperature distribution.

High efficiency digital cooler electronics for aerospace applications

NASA Astrophysics Data System (ADS)

Kirkconnell, C. S.; Luong, T. T.; Shaw, L. S.; Murphy, J. B.; Moody, E. A.; Lisiecki, A. L.; Ellis, M. J.

2014-06-01

Closed-cycle cryogenic refrigerators, or cryocoolers, are an enabling technology for a wide range of aerospace applications, mostly related to infrared (IR) sensors. While the industry focus has tended to be on the mechanical cryocooler thermo mechanical unit (TMU) alone, implementation on a platform necessarily consists of the combination of the TMU and a mating set of command and control electronics. For some applications the cryocooler electronics (CCE) are technologically simple and low cost relative to the TMU, but this is not always the case. The relative cost and complexity of the CCE for a space-borne application can easily exceed that of the TMU, primarily due to the technical constraints and cost impacts introduced by the typical space radiation hardness and reliability requirements. High end tactical IR sensor applications also challenge the state of the art in cryocooler electronics, such as those for which temperature setpoint and frequency must be adjustable, or those where an informative telemetry set must be supported, etc. Generally speaking for both space and tactical applications, it is often the CCE that limits the rated lifetime and reliability of the cryocooler system. A family of high end digital cryocooler electronics has been developed to address these needs. These electronics are readily scalable from 10W to 500W output capacity; experimental performance data for nominally 25W and 100W variants are presented. The combination of a FPGA-based controller and dual H-bridge motor drive architectures yields high efficiency (>92% typical) and precision temperature control (+/- 30 mK typical) for a wide range of Stirling-class mechanical cryocooler types and vendors. This paper focuses on recent testing with the AIM INFRAROT-MODULE GmbH (AIM) SX030 and AIM SF100 cryocoolers.

Digital Pinhole Camera

ERIC Educational Resources Information Center

Lancor, Rachael; Lancor, Brian

2014-01-01

In this article we describe how the classic pinhole camera demonstration can be adapted for use with digital cameras. Students can easily explore the effects of the size of the pinhole and its distance from the sensor on exposure time, magnification, and image quality. Instructions for constructing a digital pinhole camera and our method for…

Multi-sensor Array for High Altitude Balloon Missions to the Stratosphere

NASA Astrophysics Data System (ADS)

Davis, Tim; McClurg, Bryce; Sohl, John

2008-10-01

We have designed and built a microprocessor controlled and expandable multi-sensor array for data collection on near space missions. Weber State University has started a high altitude research balloon program called HARBOR. This array has been designed to data log a base set of measurements for every flight and has room for six guest instruments. The base measurements are absolute pressure, on-board temperature, 3-axis accelerometer for attitude measurement, and 2-axis compensated magnetic compass. The system also contains a real time clock and circuitry for logging data directly to a USB memory stick. In typical operation the measurements will be cycled through in sequence and saved to the memory stick along with the clock's time stamp. The microprocessor can be reprogrammed to adapt to guest experiments with either analog or digital interfacing. This system will fly with every mission and will provide backup data collection for other instrumentation for which the primary task is measuring atmospheric pressure and temperature. The attitude data will be used to determine the orientation of the onboard camera systems to aid in identifying features in the images. This will make these images easier to use for any future GIS (geographic information system) remote sensing missions.

Using a Floating-Gate MOS Transistor as a Transducer in a MEMS Gas Sensing System

PubMed Central

Barranca, Mario Alfredo Reyes; Mendoza-Acevedo, Salvador; Flores-Nava, Luis M.; Avila-García, Alejandro; Vazquez-Acosta, E. N.; Moreno-Cadenas, José Antonio; Casados-Cruz, Gaspar

2010-01-01

Floating-gate MOS transistors have been widely used in diverse analog and digital applications. One of these is as a charge sensitive device in sensors for pH measurement in solutions or using gates with metals like Pd or Pt for hydrogen sensing. Efforts are being made to monolithically integrate sensors together with controlling and signal processing electronics using standard technologies. This can be achieved with the demonstrated compatibility between available CMOS technology and MEMS technology. In this paper an in-depth analysis is done regarding the reliability of floating-gate MOS transistors when charge produced by a chemical reaction between metallic oxide thin films with either reducing or oxidizing gases is present. These chemical reactions need temperatures around 200 °C or higher to take place, so thermal insulation of the sensing area must be assured for appropriate operation of the electronics at room temperature. The operation principle of the proposal here presented is confirmed by connecting the gate of a conventional MOS transistor in series with a Fe2O3 layer. It is shown that an electrochemical potential is present on the ferrite layer when reacting with propane. PMID:22163478

Fiber-optic sensor demonstrator (FSD) preliminary test results on PROBA-2

NASA Astrophysics Data System (ADS)

Kruzelecky, Roman V.; Zou, Jing; Haddad, Emile; Jamroz, Wes; Ricci, Francesco; Edwards, Eric; McKenzie, Iain; Vuilleumier, Pierrik

2017-11-01

Fiber Sensor Demonstrator (FSD) developed by MPB Communications (MPBC) is the first demonstration of a full fiber-optic sensor network in the space environment on a satellite. FSD has been launched on ESA's Proba-2 satellite in November 2009. FSD contains twelve temperature sensors to measure the temperature at different locations in the satellite, and one High-Temperature sensor to measure the transient high temperature in the thruster, as well as one pressure sensor to measure the xenon tank pressure. First set of on-orbit test data were obtained in January 2010. The FSD unit successfully established the communication with Proba-2. The temperature of FSD unit was also acquired through a AD590 sensor inside the unit. The measurements of all the optical fiber sensor lines will be evaluated after the testing results obtained. The FSD contains twelve specially-packaged FBG temperature sensors to measure the temperature at different locations in the propulsion system and the spacecraft over the range of -60°C to +120°C. A high-temperature sensor is provided to measure the transient temperature response of the thruster to beyond 350°C. There is also an innovative P/T sensor that provides both temperature and pressure measurements of the Xe propellant tank. The preliminary data of on-orbit functional testing and temperature measurements are provided mainly in Section 6.

CMOS Imaging Sensor Technology for Aerial Mapping Cameras

NASA Astrophysics Data System (ADS)

Neumann, Klaus; Welzenbach, Martin; Timm, Martin

2016-06-01

In June 2015 Leica Geosystems launched the first large format aerial mapping camera using CMOS sensor technology, the Leica DMC III. This paper describes the motivation to change from CCD sensor technology to CMOS for the development of this new aerial mapping camera. In 2002 the DMC first generation was developed by Z/I Imaging. It was the first large format digital frame sensor designed for mapping applications. In 2009 Z/I Imaging designed the DMC II which was the first digital aerial mapping camera using a single ultra large CCD sensor to avoid stitching of smaller CCDs. The DMC III is now the third generation of large format frame sensor developed by Z/I Imaging and Leica Geosystems for the DMC camera family. It is an evolution of the DMC II using the same system design with one large monolithic PAN sensor and four multi spectral camera heads for R,G, B and NIR. For the first time a 391 Megapixel large CMOS sensor had been used as PAN chromatic sensor, which is an industry record. Along with CMOS technology goes a range of technical benefits. The dynamic range of the CMOS sensor is approx. twice the range of a comparable CCD sensor and the signal to noise ratio is significantly better than with CCDs. Finally results from the first DMC III customer installations and test flights will be presented and compared with other CCD based aerial sensors.

NASA Tech Briefs, July 2004

NASA Technical Reports Server (NTRS)

2004-01-01

Topics: Optoelectronic Sensor System for Guidance in Docking; Hybrid Piezoelectric/Fiber-Optic Sensor Sheets; Multisensor Arrays for Greater Reliability and Accuracy; Integrated-Optic Oxygen Sensors; Ka-Band Autonomous Formation Flying Sensor; CMOS VLSI Active-Pixel Sensor for Tracking; Lightweight, Self-Deploying Foam Antenna Structures; Electrically Small Microstrip Quarter-Wave Monopole Antennas; A 2-to-28-MHz Phase-Locked Loop; Portable Electromyograph; Open-Source Software for Modeling of Nanoelectronic Devices; Software for Generating Strip Maps from SAR Data; Calibration Software for use with Jurassicprok; Software for Probabilistic Risk Reduction; Software Processes SAR Motion-Measurement Data; Improved Method of Purifying Carbon Nanotubes; Patterned Growth of Carbon Nanotubes or Nanofibers; Lightweight, Rack-Mountable Composite Cold Plate/Shelves; SiC-Based Miniature High-Temperature Cantilever Anemometer; Inlet Housing for a Partial-Admission Turbine; Lightweight Thermoformed Structural Components and Optics; Growing High-Quality InAs Quantum Dots for Infrared Lasers; Selected Papers on Protoplanetary Disks; Module for Oxygenating Water without Generating Bubbles; Coastal Research Imaging Spectrometer; Rapid Switching and Modulation by use of Coupled VCSELs; Laser-Induced-Fluorescence Photogrammetry and Videogrammetry; Laboratory Apparatus Generates Dual-Species Cold Atomic Beam; Laser Ablation of Materials for Propulsion of Spacecraft; Small Active Radiation Monitor; Hybrid Image-Plane/Stereo Manipulation; Partitioning a Gridded Rectangle into Smaller Rectangles; Digital Radar-Signal Processors Implemented in FPGAs; Part 1 of a Computational Study of a Drop-Laden Mixing Layer; and Some Improvements in Signal-Conditioning Circuits.

Micromachined lab-on-a-tube sensors for simultaneous brain temperature and cerebral blood flow measurements.

PubMed

Li, Chunyan; Wu, Pei-Ming; Hartings, Jed A; Wu, Zhizhen; Cheyuo, Cletus; Wang, Ping; LeDoux, David; Shutter, Lori A; Ramaswamy, Bharat Ram; Ahn, Chong H; Narayan, Raj K

2012-08-01

This work describes the development of a micromachined lab-on-a-tube device for simultaneous measurement of brain temperature and regional cerebral blood flow. The device consists of two micromachined gold resistance temperature detectors with a 4-wire configuration. One is used as a temperature sensor and the other as a flow sensor. The temperature sensor operates with AC excitation current of 500 μA and updates its outputs at a rate of 5 Hz. The flow sensor employs a periodic heating and cooling technique under constant-temperature mode and updates its outputs at a rate of 0.1 Hz. The temperature sensor is also used to compensate for temperature changes during the heating period of the flow sensor to improve the accuracy of flow measurements. To prevent thermal and electronic crosstalk between the sensors, the temperature sensor is located outside the "thermal influence" region of the flow sensor and the sensors are separated into two different layers with a thin-film Copper shield. We evaluated the sensors for accuracy, crosstalk and long-term drift in human blood-stained cerebrospinal fluid. These in vitro experiments showed that simultaneous temperature and flow measurements with a single lab-on-a-tube device are accurate and reliable over the course of 5 days. It has a resolution of 0.013 °C and 0.18 ml/100 g/min; and achieves an accuracy of 0.1 °C and 5 ml/100 g/min for temperature and flow sensors respectively. The prototype device and techniques developed here establish a foundation for a multi-sensor lab-on-a-tube, enabling versatile multimodality monitoring applications.

Strain monitoring of bismaleimide composites using embedded microcavity sensor

NASA Astrophysics Data System (ADS)

Kaur, Amardeep; Anandan, Sudharshan; Yuan, Lei; Watkins, Steve E.; Chandrashekhara, K.; Xiao, Hai; Phan, Nam

2016-03-01

A type of extrinsic Fabry-Perot interferometer (EFPI) fiber optic sensor, i.e., the microcavity strain sensor, is demonstrated for embedded, high-temperature applications. The sensor is fabricated using a femtosecond (fs) laser. The fs-laser-based fabrication makes the sensor thermally stable to sustain operating temperatures as high as 800°C. The sensor has low sensitivity toward the temperature as compared to its response toward the applied strain. The performance of the EFPI sensor is tested in an embedded application. The host material is carbon fiber/bismaleimide (BMI) composite laminate that offer thermally stable characteristics at high ambient temperatures. The sensor exhibits highly linear response toward the temperature and strain. Analytical work done with embedded optical-fiber sensors using the out-of-autoclave BMI laminate was limited until now. The work presented in this paper offers an insight into the strain and temperature interactions of the embedded sensors with the BMI composites.

Establishing imaging sensor specifications for digital still cameras

NASA Astrophysics Data System (ADS)

Kriss, Michael A.

2007-02-01

Digital Still Cameras, DSCs, have now displaced conventional still cameras in most markets. The heart of a DSC is thought to be the imaging sensor, be it Full Frame CCD, and Interline CCD, a CMOS sensor or the newer Foveon buried photodiode sensors. There is a strong tendency by consumers to consider only the number of mega-pixels in a camera and not to consider the overall performance of the imaging system, including sharpness, artifact control, noise, color reproduction, exposure latitude and dynamic range. This paper will provide a systematic method to characterize the physical requirements of an imaging sensor and supporting system components based on the desired usage. The analysis is based on two software programs that determine the "sharpness", potential for artifacts, sensor "photographic speed", dynamic range and exposure latitude based on the physical nature of the imaging optics, sensor characteristics (including size of pixels, sensor architecture, noise characteristics, surface states that cause dark current, quantum efficiency, effective MTF, and the intrinsic full well capacity in terms of electrons per square centimeter). Examples will be given for consumer, pro-consumer, and professional camera systems. Where possible, these results will be compared to imaging system currently on the market.

High-Temperature Piezoelectric Sensing

PubMed Central

Jiang, Xiaoning; Kim, Kyungrim; Zhang, Shujun; Johnson, Joseph; Salazar, Giovanni

2014-01-01

Piezoelectric sensing is of increasing interest for high-temperature applications in aerospace, automotive, power plants and material processing due to its low cost, compact sensor size and simple signal conditioning, in comparison with other high-temperature sensing techniques. This paper presented an overview of high-temperature piezoelectric sensing techniques. Firstly, different types of high-temperature piezoelectric single crystals, electrode materials, and their pros and cons are discussed. Secondly, recent work on high-temperature piezoelectric sensors including accelerometer, surface acoustic wave sensor, ultrasound transducer, acoustic emission sensor, gas sensor, and pressure sensor for temperatures up to 1,250 °C were reviewed. Finally, discussions of existing challenges and future work for high-temperature piezoelectric sensing are presented. PMID:24361928

AlGaN Nanostructures with Extremely High Room-Temperature Internal Quantum Efficiency of Emission Below 300 nm

NASA Astrophysics Data System (ADS)

Toropov, A. A.; Shevchenko, E. A.; Shubina, T. V.; Jmerik, V. N.; Nechaev, D. V.; Evropeytsev, E. A.; Kaibyshev, V. Kh.; Pozina, G.; Rouvimov, S.; Ivanov, S. V.

2017-07-01

We present theoretical optimization of the design of a quantum well (QW) heterostructure based on AlGaN alloys, aimed at achievement of the maximum possible internal quantum efficiency of emission in the mid-ultraviolet spectral range below 300 nm at room temperature. A sample with optimized parameters was fabricated by plasma-assisted molecular beam epitaxy using the submonolayer digital alloying technique for QW formation. High-angle annular dark-field scanning transmission electron microscopy confirmed strong compositional disordering of the thus-fabricated QW, which presumably facilitates lateral localization of charge carriers in the QW plane. Stress evolution in the heterostructure was monitored in real time during growth using a multibeam optical stress sensor intended for measurements of substrate curvature. Time-resolved photoluminescence spectroscopy confirmed that radiative recombination in the fabricated sample dominated in the whole temperature range up to 300 K. This leads to record weak temperature-induced quenching of the QW emission intensity, which at 300 K does not exceed 20% of the low-temperature value.

Effects of Three Types of Digital Camera Sensors on Dental Specialists' Perception of Smile Esthetics: A Preliminary Double-Blind Clinical Trial.

PubMed

Sajjadi, Seyed Hadi; Khosravanifard, Behnam; Moazzami, Fatemeh; Rakhshan, Vahid; Esmaeilpour, Mozhgan

2016-12-01

The effect of image quality or dental specialties on the subjective judgment of facial beauty has not been evaluated in any study. This study assessed the effect of digital sensors and specialties on the perception of smile beauty. In the first phase of this double-blind clinical trial, 40 female smile photographs (taken from dental students) were evaluated by a panel of three prosthodontists, six orthodontists, and three specialists in restorative dentistry to select the most beautiful smiles. In the second phase, the 20 students having the most appealing smiles were again photographed in standard conditions, but this time with three different digital sensors: full-frame 21.1-megapixel, half-frame 18.0-megapixel, and compact 10.4-megapixel. The same panel judged smile beauty on a visual analog scale. The referees were blinded to the type of sensors, and the images were all coded. The data were analyzed using two-way ANOVA, Kruskal-Wallis, and Mann-Whitney U tests (α = 0.05 and 0.0167). The mean scores for full-frame, half-frame, and compact sensors were 6.70 ± 1.30, 4.56 ± 1.29, and 4.40 ± 1.39 [out of 10], respectively (Kruskal-Wallis p < 0.0001). The differences between the full-frame and the other sensors were statistically significant (Mann-Whitney p < 0.01); however, the difference between the half-frame and compact sensors was not statistically significant (p > 0.1). Sensors (ANOVA p < 0.00001) but not specialties (p = 0.687) affected the perception of beauty. According to the results of this study, image quality affected the perception of smile beauty. The full-frame sensor produced consistently better results and was recommended over half-frame and compact sensors. Dentists of different specialties might have similar standards of smile beauty, although this needs further assessment. © 2015 by the American College of Prosthodontists.

Loran-C digital word generator for use with a KIM-1 microprocessor system

NASA Technical Reports Server (NTRS)

Nickum, J. D.

1977-01-01

The problem of translating the time of occurrence of received Loran-C pulses into a time, referenced to a particular period of occurrence is addressed and applied to the design of a digital word generator for a Loran-C sensor processor package. The digital information from this word generator is processed in a KIM-1 microprocessor system which is based on the MOS 6502 CPU. This final system will consist of a complete time difference sensor processor for determining position information using Loran-C charts. The system consists of the KIM-1 microprocessor module, a 4K RAM memory board, a user interface, and the Loran-C word generator.

Digital flight control systems

NASA Technical Reports Server (NTRS)

Caglayan, A. K.; Vanlandingham, H. F.

1977-01-01

The design of stable feedback control laws for sampled-data systems with variable rate sampling was investigated. These types of sampled-data systems arise naturally in digital flight control systems which use digital actuators where it is desirable to decrease the number of control computer output commands in order to save wear and tear of the associated equipment. The design of aircraft control systems which are optimally tolerant of sensor and actuator failures was also studied. Detection of the failed sensor or actuator must be resolved and if the estimate of the state is used in the control law, then it is also desirable to have an estimator which will give the optimal state estimate even under the failed conditions.

Capacitance-digital and impedance converter as electrical tomography measurement system for biological tissue

NASA Astrophysics Data System (ADS)

Ikhsanti, Mila Izzatul; Bouzida, Rana; Wijaya, Sastra Kusuma; Rohmadi, Muttakin, Imamul; Taruno, Warsito P.

2017-02-01

This research aims to explore the feasibility of capacitance-digital converter and impedance converter for measurement module in electrical capacitance tomography (ECT) system. ECT sensor used was a cylindrical sensor having 8 electrodes. Absolute capacitance measurement system based on Sigma Delta Capacitance-to-Digital-Converter AD7746 has been shown to produce measurement with high resolution. Whereas, capacitance measurement with wide range of frequency is possible using Impedance Converter AD5933. Comparison of measurement accuracy by both AD7746 and AD5933 with reference of LCR meter was evaluated. Biological matters represented in water and oil were treated as object reconstructed into image using linear back projection (LBP) algorithm.

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.

High spatio-temporal resolution observations of crater-lake temperatures at Kawah Ijen volcano, East Java, Indonesia

USGS Publications Warehouse

Lewicki, Jennifer L.; Corentin Caudron,; Vincent van Hinsberg,; George Hilley,

2016-01-01

The crater lake of Kawah Ijen volcano, East Java, Indonesia, has displayed large and rapid changes in temperature at point locations during periods of unrest, but measurement techniques employed to-date have not resolved how the lake’s thermal regime has evolved over both space and time. We applied a novel approach for mapping and monitoring variations in crater-lake apparent surface (“skin”) temperatures at high spatial (~32 cm) and temporal (every two minutes) resolution at Kawah Ijen on 18 September 2014. We used a ground-based FLIR T650sc camera with digital and thermal infrared (TIR) sensors from the crater rim to collect (1) a set of visible imagery around the crater during the daytime and (2) a time series of co-located visible and TIR imagery at one location from pre-dawn to daytime. We processed daytime visible imagery with the Structure-from-Motion photogrammetric method to create a digital elevation model onto which the time series of TIR imagery was orthorectified and georeferenced. Lake apparent skin temperatures typically ranged from ~21 to 33oC. At two locations, apparent skin temperatures were ~ 4 and 7 oC less than in-situ lake temperature measurements at 1.5 and 5 m depth, respectively. These differences, as well as the large spatio-temporal variations observed in skin temperatures, were likely largely associated with atmospheric effects such as evaporative cooling of the lake surface and infrared absorption by water vapor and SO2. Calculations based on orthorectified TIR imagery thus yielded underestimates of volcanic heat fluxes into the lake, whereas volcanic heat fluxes estimated based on in-situ temperature measurements (68 to 111 MW) were likely more representative of Kawah Ijen in a quiescent state. The ground-based imaging technique should provide a valuable tool to continuously monitor crater-lake temperatures and contribute insight into the spatio-temporal evolution of these temperatures associated with volcanic activity.

Micro-electro-mechanical systems (MEMS) and agile lensing-based modules for communications, sensing and signal processing

NASA Astrophysics Data System (ADS)

Reza, Syed Azer

This dissertation proposes the use of the emerging Micro-Electro-Mechanical Systems (MEMS) and agile lensing optical device technologies to design novel and powerful signal conditioning and sensing modules for advanced applications in optical communications, physical parameter sensing and RF/optical signal processing. For example, these new module designs have experimentally demonstrated exceptional features such as stable loss broadband operations and high > 60 dB optical dynamic range signal filtering capabilities. The first part of the dissertation describes the design and demonstration of digital MEMS-based signal processing modules for communication systems and sensor networks using the TI DLP (Digital Light Processing) technology. Examples of such modules include optical power splitters, narrowband and broadband variable fiber optical attenuators, spectral shapers and filters. Compared to prior works, these all-digital designs have advantages of repeatability, accuracy, and reliability that are essential for advanced communications and sensor applications. The next part of the dissertation proposes, analyzes and demonstrates the use of analog opto-fluidic agile lensing technology for sensor networks and test and measurement systems. Novel optical module designs for distance sensing, liquid level sensing, three-dimensional object shape sensing and variable photonic delay lines are presented and experimentally demonstrated. Compared to prior art module designs, the proposed analog-mode modules have exceptional performances, particularly for extreme environments (e.g., caustic liquids) where the free-space agile beam-based sensor provide remote non-contact access for physical sensing operations. The dissertation also presents novel modules involving hybrid analog-digital photonic designs that make use of the different optical device technologies to deliver the best features of both analog and digital optical device operations and controls. Digital controls are achieved through the use of the digital MEMS technology and analog controls are realized by employing opto-fluidic agile lensing technology and acousto-optic technology. For example, variable fiber-optic attenuators and spectral filters are proposed using the hybrid design. Compared to prior art module designs, these hybrid designs provide a higher module dynamic range and increased resolution that are critical in various advanced system applications. In summary, the dissertation shows the added power of hybrid optical designs using both the digital and analog photonic signal processing versus just all-digital or all-analog module designs.

Automobile Crash Sensor Signal Processor

DOT National Transportation Integrated Search

1973-11-01

The crash sensor signal processor described interfaces between an automobile-installed doppler radar and an air bag activating solenoid or equivalent electromechanical device. The processor utilizes both digital and analog techniques to produce an ou...

A novel CMOS transducer for giant magnetoresistance sensors.

PubMed

Luong, Van Su; Lu, Chih-Cheng; Yang, Jing-Wen; Jeng, Jen-Tzong

2017-02-01

In this work, an ASIC (application specific integrated circuits) transducer circuit for field modulated giant magnetoresistance (GMR) sensors was designed and fabricated using a 0.18-μm CMOS process. The transducer circuits consist of a frequency divider, a digital phase shifter, an instrument amplifier, and an analog mixer. These comprise a mix of analog and digital circuit techniques. The compact chip size of 1.5 mm × 1.5 mm for both analog and digital parts was achieved using the TSMC18 1P6M (1-polysilicon 6-metal) process design kit, and the characteristics of the system were simulated using an HSpice simulator. The output of the transducer circuit is the result of the first harmonic detection, which resolves the modulated field using a phase sensitive detection (PSD) technique and is proportional to the measured magnetic field. When the dual-bridge GMR sensor is driven by the transducer circuit with a current of 10 mA at 10 kHz, the observed sensitivity of the field sensor is 10.2 mV/V/Oe and the nonlinearity error was 3% in the linear range of ±1 Oe. The performance of the system was also verified by rotating the sensor system horizontally in earth's magnetic field and recording the sinusoidal output with respect to the azimuth angle, which exhibits an error of less than ±0.04 Oe. These results prove that the ASIC transducer is suitable for driving the AC field modulated GMR sensors applied to geomagnetic measurement.

Mechanical properties of the human hand digits: Age-related differences

PubMed Central

Park, Jaebum; Pazin, Nemanja; Friedman, Jason; Zatsiorsky, Vladimir M.; Latash, Mark L.

2014-01-01

Background Mechanical properties of human digits may have significant implications for the hand function. We quantified several mechanical characteristics of individual digits in young and older adults. Methods Digit tip friction was measured at several normal force values using a method of induced relative motion between the digit tip and the object surface. A modified quick-release paradigm was used to estimate digit apparent stiffness, damping, and inertial parameters. The subjects grasped a vertical handle instrumented with force/moment sensors using a prismatic grasp with four digits; the handle was fixed to the table. Unexpectedly, one of the sensors yielded leading to a quick displacement of the corresponding digit. A second-order, linear model was used to fit the force/displacement data. Findings Friction of the digit pads was significantly lower in older adults. The apparent stiffness coefficient values were higher while the damping coefficients were lower in older adults leading to lower damping ratio. The damping ratio was above unity for most data in young adults and below unity for older adults. Quick release of a digit led to force changes in other digits of the hand, likely due to inertial hand properties. These phenomena of “mechanical enslaving” were smaller in older adults although no significant difference was found in the inertial parameter in the two groups. Interpretations The decreased friction and damping ratio present challenges for the control of everyday prehensile tasks. They may lead to excessive digit forces and low stability of the grasped object. PMID:24355703

Tracking a Head-Mounted Display in a Room-Sized Environment with Head-Mounted Cameras

DTIC Science & Technology

1990-04-01

poor resolution and a very limited working volume [Wan90]. 4 OPTOTRAK [Nor88] uses one camera with two dual-axis CCD infrared position sensors. Each...Nor88] Northern Digital. Trade literature on Optotrak - Northern Digital’s Three Dimensional Optical Motion Tracking and Analysis System. Northern Digital

Single chip camera active pixel sensor

NASA Technical Reports Server (NTRS)

Shaw, Timothy (Inventor); Pain, Bedabrata (Inventor); Olson, Brita (Inventor); Nixon, Robert H. (Inventor); Fossum, Eric R. (Inventor); Panicacci, Roger A. (Inventor); Mansoorian, Barmak (Inventor)

2003-01-01

A totally digital single chip camera includes communications to operate most of its structure in serial communication mode. The digital single chip camera include a D/A converter for converting an input digital word into an analog reference signal. The chip includes all of the necessary circuitry for operating the chip using a single pin.

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.

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.

Study of robust thin film PT-1000 temperature sensors for cryogenic process control applications

NASA Astrophysics Data System (ADS)

Ramalingam, R.; Boguhn, D.; Fillinger, H.; Schlachter, S. I.; Süßer, M.

2014-01-01

In some cryogenic process measurement applications, for example, in hydrogen technology and in high temperature superconductor based generators, there is a need of robust temperature sensors. These sensors should be able to measure the large temperature range of 20 - 500 K with reasonable resolution and accuracy. Thin film PT 1000 sensors could be a choice to cover this large temperature range. Twenty one sensors selected from the same production batch were tested for their temperature sensitivity which was then compared with different batch sensors. Furthermore, the sensor's stability was studied by subjecting the sensors to repeated temperature cycles of 78-525 K. Deviations in the resistance were investigated using ice point calibration and water triple point calibration methods. Also the study of directional oriented intense static magnetic field effects up to 8 Oersted (Oe) were conducted to understand its magneto resistance behaviour in the cryogenic temperature range from 77 K - 15 K. This paper reports all investigation results in detail.

A 12-bit high-speed column-parallel two-step single-slope analog-to-digital converter (ADC) for CMOS image sensors.

PubMed

Lyu, Tao; Yao, Suying; Nie, Kaiming; Xu, Jiangtao

2014-11-17

A 12-bit high-speed column-parallel two-step single-slope (SS) analog-to-digital converter (ADC) for CMOS image sensors is proposed. The proposed ADC employs a single ramp voltage and multiple reference voltages, and the conversion is divided into coarse phase and fine phase to improve the conversion rate. An error calibration scheme is proposed to correct errors caused by offsets among the reference voltages. The digital-to-analog converter (DAC) used for the ramp generator is based on the split-capacitor array with an attenuation capacitor. Analysis of the DAC's linearity performance versus capacitor mismatch and parasitic capacitance is presented. A prototype 1024 × 32 Time Delay Integration (TDI) CMOS image sensor with the proposed ADC architecture has been fabricated in a standard 0.18 μm CMOS process. The proposed ADC has average power consumption of 128 μW and a conventional rate 6 times higher than the conventional SS ADC. A high-quality image, captured at the line rate of 15.5 k lines/s, shows that the proposed ADC is suitable for high-speed CMOS image sensors.

Integrated digital printing of flexible circuits for wireless sensing (Conference Presentation)

NASA Astrophysics Data System (ADS)

Mei, Ping; Whiting, Gregory L.; Schwartz, David E.; Ng, Tse Nga; Krusor, Brent S.; Ready, Steve E.; Daniel, George; Veres, Janos; Street, Bob

2016-09-01

Wireless sensing has broad applications in a wide variety of fields such as infrastructure monitoring, chemistry, environmental engineering and cold supply chain management. Further development of sensing systems will focus on achieving light weight, flexibility, low power consumption and low cost. Fully printed electronics provide excellent flexibility and customizability, as well as the potential for low cost and large area applications, but lack solutions for high-density, high-performance circuitry. Conventional electronics mounted on flexible printed circuit boards provide high performance but are not digitally fabricated or readily customizable. Incorporation of small silicon dies or packaged chips into a printed platform enables high performance without compromising flexibility or cost. At PARC, we combine high functionality c-Si CMOS and digitally printed components and interconnects to create an integrated platform that can read and process multiple discrete sensors. Our approach facilitates customization to a wide variety of sensors and user interfaces suitable for a broad range of applications including remote monitoring of health, structures and environment. This talk will describe several examples of printed wireless sensing systems. The technologies required for these sensor systems are a mix of novel sensors, printing processes, conventional microchips, flexible substrates and energy harvesting power solutions.

A sneak peek into digital innovations and wearable sensors for cardiac monitoring.

PubMed

Michard, Frederic

2017-04-01

Many mobile phone or tablet applications have been designed to control cardiovascular risk factors (obesity, smoking, sedentary lifestyle, diabetes and hypertension) or to optimize treatment adherence. Some have been shown to be useful but the long-term benefits remain to be demonstrated. Digital stethoscopes make easier the interpretation of abnormal heart sounds, and the development of pocket-sized echo machines may quickly and significantly expand the use of ultrasounds. Daily home monitoring of pulmonary artery pressures with wireless implantable sensors has been shown to be associated with a significant decrease in hospital readmissions for heart failure. There are more and more non-invasive, wireless, and wearable sensors designed to monitor heart rate, heart rate variability, respiratory rate, arterial oxygen saturation, and thoracic fluid content. They have the potential to change the way we monitor and treat patients with cardiovascular diseases in the hospital and beyond. Some may have the ability to improve quality of care, decrease the number of medical visits and hospitalization, and ultimately health care costs. Validation and outcome studies are needed to clarify, among the growing number of digital innovations and wearable sensors, which tools have real clinical value.

Relative performance of several inexpensive accelerometers

USGS Publications Warehouse

Evans, John R.; Rogers, John A.

1995-01-01

We examined the performance of several low-cost accelerometers for highly cost-driven applications in recording earthquake strong motion. We anticipate applications for such sensors in providing the lifeline and emergency-response communities with an immediate, comprehensive picture of the extent and characteristics of likely damage. We also foresee their use as 'filler' instruments sited between research-grade instruments to provide spatially detailed and near-field records of large earthquakes (on the order of 1000 stations at 600-m intervals in San Fernando Valley, population 1.2 million, for example). The latter applications would provide greatly improved attenuation relationships for building codes and design, the first examples of mainshock information (that is, potentially nonlinear regime) for microzonation, and a suite of records for structural engineers. We also foresee possible applications in monitoring structural inter-story drift during earthquakes, possibly leading to local and remote alarm functions as well as design criteria. This effort appears to be the first of its type at the USGS. It is spurred by rapid advances in sensor technology and the recognition of potential non-classical applications. In this report, we estimate sensor noise spectra, relative transfer functions and cross-axis sensitivity of six inexpensive sensors. We tested three micromachined ('silicon-chip') sensors in addition to classical force-balance and piezoelectric examples. This sample of devices is meant to be representative, not comprehensive. Sensor noise spectra were estimated by recording system output with the sensor mounted on a pneumatically supported 545-kg optical-bench isolation table. This isolation table appears to limit ground motion to below our system noise level. These noise estimates include noise introduced by signal-conditioning circuitry, the analog-to-digital converter (ADC), and noise induced in connecting wiring by ambient electromagnetic fields in our suburban laboratory. These latter sources are believed to dominate sensor noise in the quieter sensors we tested. Transfer functions were obtained relative to a research grade force-balance accelerometer (a Kinemetrics TM FBA-11) by shaking the sensors simultaneously on the same shake table and taking spectral ratios with the output of the FBA- 11. This reference sensor is said to have 120 db dynamic range (-+20 bits, though we only digitized it at 16 bits resolution and drove it with relatively small signals). We did not test temperature sensitivity, which is thought to be a significant issue at least for the silicon devices. Though these tests were not designed to be definitive (our anticipated applications do not demand research-grade precision), our tests do appear to have been successful in estimating relative transfer functions from about 0.3 to 50 Hz. Most sensors performed adequately in this range, with essentially fiat relative transfer functions. Noise tests appear to measure sensor noise well for the noisier (generally less expensive) instruments from about 0.1 to 50 Hz.

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.

Characterization techniques for incorporating backgrounds into DIRSIG

NASA Astrophysics Data System (ADS)

Brown, Scott D.; Schott, John R.

2000-07-01

The appearance of operation hyperspectral imaging spectrometers in both solar and thermal regions has lead to the development of a variety of spectral detection algorithms. The development and testing of these algorithms requires well characterized field collection campaigns that can be time and cost prohibitive. Radiometrically robust synthetic image generation (SIG) environments that can generate appropriate images under a variety of atmospheric conditions and with a variety of sensors offers an excellent supplement to reduce the scope of the expensive field collections. In addition, SIG image products provide the algorithm developer with per-pixel truth, allowing for improved characterization of the algorithm performance. To meet the needs of the algorithm development community, the image modeling community needs to supply synthetic image products that contain all the spatial and spectral variability present in real world scenes, and that provide the large area coverage typically acquired with actual sensors. This places a heavy burden on synthetic scene builders to construct well characterized scenes that span large areas. Several SIG models have demonstrated the ability to accurately model targets (vehicles, buildings, etc.) Using well constructed target geometry (from CAD packages) and robust thermal and radiometry models. However, background objects (vegetation, infrastructure, etc.) dominate the percentage of real world scene pixels and utilizing target building techniques is time and resource prohibitive. This paper discusses new methods that have been integrated into the Digital Imaging and Remote Sensing Image Generation (DIRSIG) model to characterize backgrounds. The new suite of scene construct types allows the user to incorporate both terrain and surface properties to obtain wide area coverage. The terrain can be incorporated using a triangular irregular network (TIN) derived from elevation data or digital elevation model (DEM) data from actual sensors, temperature maps, spectral reflectance cubes (possible derived from actual sensors), and/or material and mixture maps. Descriptions and examples of each new technique are presented as well as hybrid methods to demonstrate target embedding in real world imagery.

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.

A comprehensive in vitro study of image accuracy and quality for periodontal diagnosis. Part 1: the influence of X-ray generator on periodontal measurements using conventional and digital receptors.

PubMed

Vandenberghe, Bart; Corpas, Livia; Bosmans, Hilde; Yang, Jie; Jacobs, Reinhilde

2011-08-01

The aim of this study was the determination of image accuracy and quality for periodontal diagnosis using various X-ray generators with conventional and digital radiographs. Thirty-one in vitro periodontal defects were evaluated on intraoral conventional (E-, F/E-speed) and digital images (three indirect, two direct sensors). Standardised radiographs were made with an alternating current (AC), a high-frequency (HF) and a direct current (DC) X-ray unit at rising exposure times (20-160 ms with 20-ms interval) with a constant kV of 70. Three observers assessed bone levels for comparison to the gold standard. Lamina dura, contrast, trabecularisation, crater and furcation involvements were evaluated. Irrespective X-ray generator-type, measurement deviations increased at higher exposure times for solid-state, but decreased for photostimulable storage phosphor (PSP) systems. Accuracy for HF or DC was significantly higher than AC (p < 0.0001), especially at low exposure times. At 0.5- to 1-mm clinical deviation, 27-53% and 32-55% dose savings were demonstrated when using HF or DC generators compared to AC, but only for PSP. No savings were found for solid-state sensors, indicating their higher sensitivity. The use of digital sensors compared to film allowed 15-90% dose savings using the AC tube, whilst solid-state sensors allowed approximately 50% savings compared to PSP, depending on tube type and threshold level.. Accuracy of periodontal diagnosis increases when using HF or DC generators and/or digital receptors with adequate diagnostic information at lower exposure times.

FITPix COMBO—Timepix detector with integrated analog signal spectrometric readout

NASA Astrophysics Data System (ADS)

Holik, M.; Kraus, V.; Georgiev, V.; Granja, C.

2016-02-01

The hybrid semiconductor pixel detector Timepix has proven a powerful tool in radiation detection and imaging. Energy loss and directional sensitivity as well as particle type resolving power are possible by high resolution particle tracking and per-pixel energy and quantum-counting capability. The spectrometric resolving power of the detector can be further enhanced by analyzing the analog signal of the detector common sensor electrode (also called back-side pulse). In this work we present a new compact readout interface, based on the FITPix readout architecture, extended with integrated analog electronics for the detector's common sensor signal. Integrating simultaneous operation of the digital per-pixel information with the common sensor (called also back-side electrode) analog pulse processing circuitry into one device enhances the detector capabilities and opens new applications. Thanks to noise suppression and built-in electromagnetic interference shielding the common hardware platform enables parallel analog signal spectroscopy on the back side pulse signal with full operation and read-out of the pixelated digital part, the noise level is 600 keV and spectrometric resolution around 100 keV for 5.5 MeV alpha particles. Self-triggering is implemented with delay of few tens of ns making use of adjustable low-energy threshold of the particle analog signal amplitude. The digital pixelated full frame can be thus triggered and recorded together with the common sensor analog signal. The waveform, which is sampled with frequency 100 MHz, can be recorded in adjustable time window including time prior to the trigger level. An integrated software tool provides control, on-line display and read-out of both analog and digital channels. Both the pixelated digital record and the analog waveform are synchronized and written out by common time stamp.

LACIS-T - A humid wind tunnel for investigating the Interactions between Cloud Microphysics and Turbulence

NASA Astrophysics Data System (ADS)

Voigtländer, Jens; Niedermeier, Dennis; Siebert, Holger; Shaw, Raymond; Schumacher, Jörg; Stratmann, Frank

2017-04-01

To improve the fundamental and quantitative understanding of the interactions between cloud microphysical and turbulent processes, the Leibniz Institute for Tropospheric Research (TROPOS) has built up a new humid wind tunnel (LACIS-T). LACIS-T allows for the investigation of cloud microphysical processes, such as cloud droplet activation and freezing, under-well defined thermodynamic and turbulent flow conditions. It therewith allows for the straight forward continuation, extension, and completion of the cloud microphysics related investigations carried out at the Leipzig Aerosol Cloud Interaction Simulator (LACIS) under laminar flow conditions. Characterization of the wind tunnel with respect to flow, thermodynamics, and droplet microphysics is carried out with probes mounted inside (pitot tube and hot-wire anemometer for mean velocity and fluctuations, Pt100 sensor for mean temperature, cold-wire sensor for temperature fluctuations is in progress, as well as a dew-point mirror for mean water vapor concentration, a Lyman-alpha sensor for water vapor fluctuations is in progress) the measurement section, and from outside with optical detection methods (a laser light sheet is available for cloud droplet visualization, a digital holography system for detection of cloud droplet size distributions will be installed for tests in February 2017), respectively. Computational fluid dynamics (CFD) simulations have been carried out for defining suitable experimental conditions and assisting the interpretation of the experimental data. In this work, LACIS-T, its fundamental operating principle, and first preliminary results from ongoing characterization efforts will be presented.

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.

Usability of a novel digital medicine system in adults with schizophrenia treated with sensor-embedded tablets of aripiprazole.

PubMed

Peters-Strickland, Timothy; Pestreich, Linda; Hatch, Ainslie; Rohatagi, Shashank; Baker, Ross A; Docherty, John P; Markovtsova, Lada; Raja, Praveen; Weiden, Peter J; Walling, David P

2016-01-01

Digital medicine system (DMS) is a novel drug-device combination that objectively measures and reports medication ingestion. The DMS consists of medication embedded with an ingestible sensor (digital medicine), a wearable sensor, and software applications. This study evaluated usability of the DMS in adults with schizophrenia rated by both patients and their health care providers (HCPs) during 8-week treatment with prescribed doses of digital aripiprazole. Six US sites enrolled outpatients into this Phase IIa, open-label study (NCT02219009). The study comprised a screening phase, a training phase (three weekly site visits), and a 5-week independent phase. Patients and HCPs independently rated usability of and satisfaction with the DMS. Sixty-seven patients were enrolled, and 49 (73.1%) patients completed the study. The mean age (SD) of the patients was 46.6 years (9.7 years); the majority of them were male (74.6%), black (76.1%), and rated mildly ill on the Clinical Global Impression - Severity scale (70.1%). By the end of week 8 or early termination, 82.1% (55/67) of patients had replaced the wearable sensor independently or with minimal assistance, based on HCP rating. The patients used the wearable sensor for a mean (SD) of 70.7% (24.7%) and a median of 77.8% of their time in the trial. The patients contacted a call center most frequently at week 1. At the last visit, 78% (47/60) of patients were somewhat satisfied/satisfied/extremely satisfied with the DMS. A high proportion of patients with schizophrenia were able to use the DMS and reported satisfaction with the DMS. These data support the potential utility of the DMS in clinical practice.

40 CFR 63.11563 - What are my monitoring requirements?

Code of Federal Regulations, 2010 CFR

2010-07-01

... and the following requirements: (1) Locate the temperature sensor in a position that provides a representative temperature. (2) For a noncryogenic temperature range, use a temperature sensor with a minimum... procedures in the manufacturer's documentation; or (ii) By comparing the sensor output to redundant sensor...

40 CFR 63.11563 - What are my monitoring requirements?

Code of Federal Regulations, 2011 CFR

2011-07-01

... and the following requirements: (1) Locate the temperature sensor in a position that provides a representative temperature. (2) For a noncryogenic temperature range, use a temperature sensor with a minimum... procedures in the manufacturer's documentation; or (ii) By comparing the sensor output to redundant sensor...

40 CFR 63.11563 - What are my monitoring requirements?

Code of Federal Regulations, 2014 CFR

2014-07-01

... and the following requirements: (1) Locate the temperature sensor in a position that provides a representative temperature. (2) For a noncryogenic temperature range, use a temperature sensor with a minimum... procedures in the manufacturer's documentation; or (ii) By comparing the sensor output to redundant sensor...

40 CFR 63.11563 - What are my monitoring requirements?

Code of Federal Regulations, 2013 CFR

2013-07-01

... and the following requirements: (1) Locate the temperature sensor in a position that provides a representative temperature. (2) For a noncryogenic temperature range, use a temperature sensor with a minimum... procedures in the manufacturer's documentation; or (ii) By comparing the sensor output to redundant sensor...

40 CFR 63.11563 - What are my monitoring requirements?

Code of Federal Regulations, 2012 CFR

2012-07-01

... and the following requirements: (1) Locate the temperature sensor in a position that provides a representative temperature. (2) For a noncryogenic temperature range, use a temperature sensor with a minimum... procedures in the manufacturer's documentation; or (ii) By comparing the sensor output to redundant sensor...

Probeware: Illuminating the Invisible

ERIC Educational Resources Information Center

Brunsell, Eric; Horejsi, Martin

2010-01-01

Probeware is the combination of sensors and software connected to a computer or handheld device. At the heart of probeware is a digital sensor that measures a particular physical parameter. One or more sensors are plugged into an interface, a calculator, and a handheld device. With the click of a button, probeware collects and graphs data in real…

Multi-Sensor Systems Development for UXO Detection and Discrimination: Hand-Held Dual Magnetic/Electromagnetic Induction Sensor

DTIC Science & Technology

2008-04-01

5 Fluxgate magnetometer ... magnetometer into digital format, and transmitted as a single serial data string to log the Cs and fluxgate magnetometer data. After procurement...Hardware The system hardware comprises an EMI sensor, Cs vapor magnetometer , fluxgate magnetometer , hand-held data acquisition computer, integrated

Toward CMOS image sensor based glucose monitoring.

PubMed

Devadhasan, Jasmine Pramila; Kim, Sanghyo

2012-09-07

Complementary metal oxide semiconductor (CMOS) image sensor is a powerful tool for biosensing applications. In this present study, CMOS image sensor has been exploited for detecting glucose levels by simple photon count variation with high sensitivity. Various concentrations of glucose (100 mg dL(-1) to 1000 mg dL(-1)) were added onto a simple poly-dimethylsiloxane (PDMS) chip and the oxidation of glucose was catalyzed with the aid of an enzymatic reaction. Oxidized glucose produces a brown color with the help of chromogen during enzymatic reaction and the color density varies with the glucose concentration. Photons pass through the PDMS chip with varying color density and hit the sensor surface. Photon count was recognized by CMOS image sensor depending on the color density with respect to the glucose concentration and it was converted into digital form. By correlating the obtained digital results with glucose concentration it is possible to measure a wide range of blood glucose levels with great linearity based on CMOS image sensor and therefore this technique will promote a convenient point-of-care diagnosis.

Development of the smartphone-based colorimetry for multi-analyte sensing arrays.

PubMed

Hong, Jong Il; Chang, Byoung-Yong

2014-05-21

Here we report development of a smartphone app (application) that digitizes the colours of a colorimetric sensor array. A conventional colorimetric sensor array consists of multiple paper-based sensors, and reports the detection results in terms of colour change. Evaluation of the colour changes is normally done by the naked eye, which may cause uncertainties due to personal subjectivity and the surrounding conditions. Solutions have been particularly sought in smartphones as they are capable of spectrometric functions. Our report specifically focuses on development of a practical app for immediate point-of-care (POC) multi-analyte sensing without additional devices. First, the individual positions of the sensors are automatically identified by the smartphone; second, the colours measured at each sensor are digitized based on a correction algorithm; and third, the corrected colours are converted to concentration values by pre-loaded calibration curves. All through these sequential processes, the sensor array taken in a smartphone snapshot undergoes laboratory-level spectrometry. The advantages of inexpensive and convenient paper-based colorimetry and the ubiquitous smartphone are tied to achieve a ready-to-go POC diagnosis.

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.

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 silicon substrate temperature if never exposed to temperatures above about 220 °C.

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.

Digital sun sensor multi-spot operation.

PubMed

Rufino, Giancarlo; Grassi, Michele

2012-11-28

The operation and test of a multi-spot digital sun sensor for precise sun-line determination is described. The image forming system consists of an opaque mask with multiple pinhole apertures producing multiple, simultaneous, spot-like images of the sun on the focal plane. The sun-line precision can be improved by averaging multiple simultaneous measures. Nevertheless, the sensor operation on a wide field of view requires acquiring and processing images in which the number of sun spots and the related intensity level are largely variable. To this end, a reliable and robust image acquisition procedure based on a variable shutter time has been considered as well as a calibration function exploiting also the knowledge of the sun-spot array size. Main focus of the present paper is the experimental validation of the wide field of view operation of the sensor by using a sensor prototype and a laboratory test facility. Results demonstrate that it is possible to keep high measurement precision also for large off-boresight angles.

Depth map generation using a single image sensor with phase masks.

PubMed

Jang, Jinbeum; Park, Sangwoo; Jo, Jieun; Paik, Joonki

2016-06-13

Conventional stereo matching systems generate a depth map using two or more digital imaging sensors. It is difficult to use the small camera system because of their high costs and bulky sizes. In order to solve this problem, this paper presents a stereo matching system using a single image sensor with phase masks for the phase difference auto-focusing. A novel pattern of phase mask array is proposed to simultaneously acquire two pairs of stereo images. Furthermore, a noise-invariant depth map is generated from the raw format sensor output. The proposed method consists of four steps to compute the depth map: (i) acquisition of stereo images using the proposed mask array, (ii) variational segmentation using merging criteria to simplify the input image, (iii) disparity map generation using the hierarchical block matching for disparity measurement, and (iv) image matting to fill holes to generate the dense depth map. The proposed system can be used in small digital cameras without additional lenses or sensors.

Polarization maintaining fiber magnetic sensor based on the digital phase generated carrier technology

NASA Astrophysics Data System (ADS)

Zhang, Xueliang; Meng, Zhou; Hu, Zhengliang; Yang, Huayong; Song, Zhangqi; Hu, Yongming

2008-12-01

A polarization maintaining fiber (PMF) magnetic field sensor based on a digital phase generated carrier (PGC) technology is presented. A magnetic sensor constructed with two magnetostrictive strips attached on the sensing fiber is joined in the sensing arm of a fiber Michelson interferometer. The fiber optic interferometric system is made of all PMF, which inhibits the polarization-induced signal fading. The light source is a fiber laser which can be modulated directly. The PGC metnod is used to demodulate magnetic field signal avoiding phase induced interferometric signal fading, and ensure the sensing partto be all fiber structure. A fiber optic magnetic field sensor with appreciate size for the fiber optic hydrophone towed array is obtained, which can be used to sense the enviromental magnetic field along the sensing direction.This sensor is a good choice for the directional angle measurement through sensing the Earth magnetic field in the array shape measurement of a fiber optic hydrophone towed array.

CMOS image sensors as an efficient platform for glucose monitoring.

PubMed

Devadhasan, Jasmine Pramila; Kim, Sanghyo; Choi, Cheol Soo

2013-10-07

Complementary metal oxide semiconductor (CMOS) image sensors have been used previously in the analysis of biological samples. In the present study, a CMOS image sensor was used to monitor the concentration of oxidized mouse plasma glucose (86-322 mg dL(-1)) based on photon count variation. Measurement of the concentration of oxidized glucose was dependent on changes in color intensity; color intensity increased with increasing glucose concentration. The high color density of glucose highly prevented photons from passing through the polydimethylsiloxane (PDMS) chip, which suggests that the photon count was altered by color intensity. Photons were detected by a photodiode in the CMOS image sensor and converted to digital numbers by an analog to digital converter (ADC). Additionally, UV-spectral analysis and time-dependent photon analysis proved the efficiency of the detection system. This simple, effective, and consistent method for glucose measurement shows that CMOS image sensors are efficient devices for monitoring glucose in point-of-care applications.

A low-noise CMOS pixel direct charge sensor, Topmetal-II-

DOE PAGES

An, Mangmang; Chen, Chufeng; Gao, Chaosong; ...

2015-12-12

In this paper, we report the design and characterization of a CMOS pixel direct charge sensor, Topmetal-II-, fabricated in a standard 0.35 μm CMOS Integrated Circuit process. The sensor utilizes exposed metal patches on top of each pixel to directly collect charge. Each pixel contains a low-noise charge-sensitive preamplifier to establish the analog signal and a discriminator with tunable threshold to generate hits. The analog signal from each pixel is accessible through time-shared multiplexing over the entire array. Hits are read out digitally through a column-based priority logic structure. Tests show that the sensor achieved a <15e - analog noisemore » and a 200e - minimum threshold for digital readout per pixel. The sensor is capable of detecting both electrons and ions drifting in gas. Lastly, these characteristics enable its use as the charge readout device in future Time Projection Chambers without gaseous gain mechanism, which has unique advantages in low background and low rate-density experiments.« less

A low-noise CMOS pixel direct charge sensor, Topmetal-II-

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

An, Mangmang; Chen, Chufeng; Gao, Chaosong

In this paper, we report the design and characterization of a CMOS pixel direct charge sensor, Topmetal-II-, fabricated in a standard 0.35 μm CMOS Integrated Circuit process. The sensor utilizes exposed metal patches on top of each pixel to directly collect charge. Each pixel contains a low-noise charge-sensitive preamplifier to establish the analog signal and a discriminator with tunable threshold to generate hits. The analog signal from each pixel is accessible through time-shared multiplexing over the entire array. Hits are read out digitally through a column-based priority logic structure. Tests show that the sensor achieved a <15e - analog noisemore » and a 200e - minimum threshold for digital readout per pixel. The sensor is capable of detecting both electrons and ions drifting in gas. Lastly, these characteristics enable its use as the charge readout device in future Time Projection Chambers without gaseous gain mechanism, which has unique advantages in low background and low rate-density experiments.« less

Experimental study of temperature sensor for an ocean-going liquid hydrogen (LH2) carrier

NASA Astrophysics Data System (ADS)

Nakano, A.; Shimazaki, T.; Sekiya, M.; Shiozawa, H.; Aoyagi, A.; Ohtsuka, K.; Iwakiri, T.; Mikami, Z.; Sato, M.; Kinoshita, K.; Matsuoka, T.; Takayama, Y.; Yamamoto, K.

2018-04-01

The prototype temperature sensors for an ocean-going liquid hydrogen (LH2) carrier were manufactured by way of trial. All of the sensors adopted Platinum 1000 (PT-1000) resistance thermometer elements. Various configurations of preproduction temperature sensors were tested in AIST's LH2 test facility. In the experiments, a PT-1000 resistance thermometer, calibrated at the National Metrology Institute of Japan at AIST, was used as the standard thermometer. The temperatures measured by the preproduction sensors were compared with the temperatures measured by the standard thermometer, and the measurement accuracy of the temperature sensors in LH2 was investigated and discussed. It was confirmed that the measurement accuracies of the preproduction temperature sensors were within ±50 mK, which is the required measurement accuracy for a technical demonstration ocean-going LH2 carrier.

Fiber optic and laser sensors IX; Proceedings of the Meeting, Boston, MA, Sept. 3-5, 1991

NASA Technical Reports Server (NTRS)

Depaula, Ramon P. (Editor); Udd, Eric (Editor)

1991-01-01

The present volume on fiber-optic and laser sensors discusses industrial applications of fiber-optic sensors, fiber-optic temperature sensors, fiber-optic current sensors, fiber-optic pressure/displacement/vibration sensors, and generic fiber-optic systems. Attention is given to a fiber-sensor design for turbine engines, fiber-optic remote Fourier transform IR spectroscopy, near-IR fiber-optic temperature sensors, and an intensity-type fiber-optic electric current sensor. Topics addressed include fiber-optic magnetic field sensors based on the Faraday effect in new materials, diaphragm size and sensitivity for fiber-optic pressure sensors, a microbend pressure sensor for high-temperature environments, and linear position sensing by light exchange between two lossy waveguides. Also discussed are two-mode elliptical-core fiber sensors for measurement of strain and temperature, a fiber-optic interferometric X-ray dosimeter, fiber-optic interferometric sensors using multimode fibers, and optical fiber sensing of corona discharges.

Microsatellite Digital Magnetometer SMILE - Present State and Future Trends

NASA Astrophysics Data System (ADS)

Belyayev, Serhiy; Ivchenko, Nickolay

2010-05-01

The fluxgate magnetometers (FGM) are probably the most widespread instruments used onboard spacecrafts for both scientific and service purposes. The recent trend to decrease the weight and size of the spacecrafts requires creating as small as possible but enough sensitive FGM. A joint Swedish-Ukrainian team made the development of such a magnetometer and as the result the Small Magnetometer In Low mass Experiment (SMILE) - a digital fluxgate microsatellite magnetometer - was created [1]. Majority of electronic units of this FGM were combined in a digital integrated circuit - a Field Programmable Gate Array (FPGA). The FPGA provides full processing (determined by a digital correlation algorithm) of amplified and digitized fluxgate sensor output signals and provides both FGM output data and feedback signals. Such digital design makes the instrument very flexible, reduces power consumption and opens possibilities for customization of the operation modes. It allows miniaturizing the electronic unit and, together with the smallest in the world low noise three-component fluxgate sensor with the side dimension of 20 mm and weight about 20 grams only, the small but enough sensitive space qualified FGM is created. SMILE magnetometer was successfully flown onboard the NASA Cascades-2 sounding rocket, and is to fly in the LAPLander package onboard the ESA REXUS-8 student sounding rocket [2]. Unfortunately, such a design of electronic circuit does not allow us to realize all possibilities of the miniature sensor. The separate tests of the sensor with highest-class analog electronics showed that its noise level may be reduced to as low value as 10…15 picoTesla at 1 Hz. Also the use of volume compensation in the sensor provides high geometrical stability of the axes and improved performance compared to component compensated sensors. The measured parameters appear to be comparable or even better than these of best stationary FGM and, if realized in small enough volume and weight, such a sensitive but small FGM could be a good candidate for planned Lunar missions where the weight is the major restriction factor. This stimulated further research in the direction of the analysis and elimination of noise sources of digital design, as well as of the optimization of FGM electronic circuit structure. The description of the obtained results of the electronic unit upgrade and recent FGM model tests are given and future improvement directions are discussed. These works are partially supported by NSAU contract No. 1499. References: 1. Åke Forslund, Serhiy Belyayev, Nickolay Ivchenko, Göran Olsson, Terry Edberg and Andriy Marusenkov, Miniaturized digital fluxgate magnetometer for small spacecraft applications 2008 Meas. Sci. Technol. 19 2. T. Sundberg, N. Ivchenko, D. Borglund, P. Ahlen, M. Gustavsson, C. Jonsson, J. Juhlen, O. Neunet, J. Sandstrom, E. Sund, M. Wartelski, C. Westlund, L. Xin, Small Recoverable Payload for Deployable Sounding Rocket Experiments. ESA Special Publication SP671

THOR Field and Wave Processor - FWP

NASA Astrophysics Data System (ADS)

Soucek, Jan; Rothkaehl, Hanna; Balikhin, Michael; Zaslavsky, Arnaud; Nakamura, Rumi; Khotyaintsev, Yuri; Uhlir, Ludek; Lan, Radek; Yearby, Keith; Morawski, Marek; Winkler, Marek

2016-04-01

If selected, Turbulence Heating ObserveR (THOR) will become the first mission ever flown in space dedicated to plasma turbulence. The Fields and Waves Processor (FWP) is an integrated electronics unit for all electromagnetic field measurements performed by THOR. FWP will interface with all fields sensors: electric field antennas of the EFI instrument, the MAG fluxgate magnetometer and search-coil magnetometer (SCM) and perform data digitization and on-board processing. FWP box will house multiple data acquisition sub-units and signal analyzers all sharing a common power supply and data processing unit and thus a single data and power interface to the spacecraft. Integrating all the electromagnetic field measurements in a single unit will improve the consistency of field measurement and accuracy of time synchronization. The feasibility of making highly sensitive electric and magnetic field measurements in space has been demonstrated by Cluster (among other spacecraft) and THOR instrumentation complemented by a thorough electromagnetic cleanliness program will further improve on this heritage. Taking advantage of the capabilities of modern electronics, FWP will provide simultaneous synchronized waveform and spectral data products at high time resolution from the numerous THOR sensors, taking advantage of the large telemetry bandwidth of THOR. FWP will also implement a plasma a resonance sounder and a digital plasma quasi-thermal noise analyzer designed to provide high cadence measurements of plasma density and temperature complementary to data from particle instruments. FWP will be interfaced with the particle instrument data processing unit (PPU) via a dedicated digital link which will enable performing on board correlation between waves and particles, quantifying the transfer of energy between waves and particles. The FWP instrument shall be designed and built by an international consortium of scientific institutes from Czech Republic, Poland, France, UK, Sweden and Austria.

The multiparameter station at Galeras Volcano (Colombia): concept and realization

NASA Astrophysics Data System (ADS)

Seidl, Dieter; Hellweg, Margaret; Calvache, Marta; Gomez, Diego; Ortega, Adriana; Torres, Roberto; Böker, Franz; Buttkus, Burkhard; Faber, Eckhard; Greinwald, Siegfried

2003-07-01

Volcanoes are complex systems, in which the interaction of many different physical and chemical factors and processes contribute to changes in activity. In the past 40 years, our ability to observe and quantify short-term changes in a volcano's activity has improved due to the installation of seismometers and tiltmeters and the continuous records they provide. However, due to instrumental limitations, the observations have mainly been used phenomenologically, to draw inferences about possible changes on the basis of previous experience. Since 1995, the Bundesanstalt für Geowissenschaften und Rohstoffe (BGR) and the Instituto de Investigación e Información Geocientífica, Minero-Ambiental y Nuclear (INGEOMINAS) have been working to develop and deploy a multiparameter (MP) station on Galeras Volcano, Colombia. This station is designed to concurrently measure various geophysical and geochemical parameters. It includes three broadband seismometers at the crater rim, as well as a more remotely located, broadband seismic reference. At other locations in the crater or on the rim, electromagnetic probes, an infrasound sensor and a weather station are operating. The data from these sensors are digitized at each site with 24-bit digitizers and transmitted by spread-spectrum radio, via repeater when necessary, to the Observatorio Vulcanológico y Sismológico (OVP) in the city of Pasto. There they are received and displayed on a networked personal computer and recorded continuously. The data flow into the routine analysis procedures of the OVP and the continuous data are archived on CD. In addition to the other sensors, a system of specially developed sensors continuously monitors the chemistry and physics of the gases at fumaroles on the active cone. The data from this system are also transmitted in realtime to OVP and recorded. The continuous recordings of the MP station are supplemented by regular thermographic measurements of the surface temperature in the crater using an infrared camera. Joint analysis and interpretation of the data streams from the many sensors of the MP station will improve our understanding of the physical processes occurring in Galeras Volcano.

Inexpensive, Low Power, Open-Source Data Logging in the Field

NASA Astrophysics Data System (ADS)

Sandell, C. T.; Wickert, A. D.

2016-12-01

Collecting a robust data set of environmental conditions with commercial equipment is often cost prohibitive. I present the ALog, a general-purpose, inexpensive, low-power, open-source data logger that has proven its durability on long-term deployments in the harsh conditions of high altitude glaciers and humid river deltas. The ALog was developed to fill the need for a capable, rugged, easy-to-use, inexpensive, open-source hardware targeted at long-term remote deployment in nearly any environment. Building on the popular Arduino platform, the hardware features a high-precision clock, full size SD card slot for high-volume data storage, screw terminals, six analog inputs, two digital inputs, one digital interrupt, 3.3V and 5V power outputs, and SPI and I2C communication capability. The design is focused on extremely low power consumption allowing the Alog to be deployed for years on a single set of common alkaline batteries. The power efficiency of the Alog eliminates the difficulties associated with field power collection including additional hardware and installation costs, dependence on weather conditions, possible equipment failure, and the transport of bulky/heavy equipment to a remote site. Battery power increases suitable data collection sites (too shaded for photovoltaics) and allows for low profile installation options (including underground). The ALog has gone through continuous development with over four years of successful data collection in hydrologic field research. Over this time, software support for a wide range of sensors has been made available such as ultrasonic rangefinders (for water level, snow accumulation and glacial melt), temperature sensors (air and groundwater), humidity sensors, pyranometers, inclinometers, rain gauges, soil moisture and water potential sensors, resistance-based tools to measure frost heave, and cameras that trigger on events. The software developed for use with the ALog allows simple integration of established commercial sensors, including example implementation code so users with limited programming knowledge can get up and running with ease. All development files including design schematics, circuit board layouts, and source code files are open-source to further eliminate barriers to its use and allow community development contribution.

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 temperature control and signal conditioning, and packaging designed for high temperatures is necessary for the array to survive the engine environment.

A novel digital image sensor with row wise gain compensation for Hyper Spectral Imager (HySI) application

NASA Astrophysics Data System (ADS)

Lin, Shengmin; Lin, Chi-Pin; Wang, Weng-Lyang; Hsiao, Feng-Ke; Sikora, Robert

2009-08-01

A 256x512 element digital image sensor has been developed which has a large pixel size, slow scan and low power consumption for Hyper Spectral Imager (HySI) applications. The device is a mixed mode, silicon on chip (SOC) IC. It combines analog circuitry, digital circuitry and optical sensor circuitry into a single chip. This chip integrates a 256x512 active pixel sensor array, a programming gain amplifier (PGA) for row wise gain setting, I2C interface, SRAM, 12 bit analog to digital convertor (ADC), voltage regulator, low voltage differential signal (LVDS) and timing generator. The device can be used for 256 pixels of spatial resolution and 512 bands of spectral resolution ranged from 400 nm to 950 nm in wavelength. In row wise gain readout mode, one can set a different gain on each row of the photo detector by storing the gain setting data on the SRAM thru the I2C interface. This unique row wise gain setting can be used to compensate the silicon spectral response non-uniformity problem. Due to this unique function, the device is suitable for hyper-spectral imager applications. The HySI camera located on-board the Chandrayaan-1 satellite, was successfully launched to the moon on Oct. 22, 2008. The device is currently mapping the moon and sending back excellent images of the moon surface. The device design and the moon image data will be presented in the paper.

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 significant error factor comparable to ±1% manufacturer's accuracy.

Design of a CMOS readout circuit on ultra-thin flexible silicon chip for printed strain gauges

NASA Astrophysics Data System (ADS)

Elsobky, Mourad; Mahsereci, Yigit; Keck, Jürgen; Richter, Harald; Burghartz, Joachim N.

2017-09-01

Flexible electronics represents an emerging technology with features enabling several new applications such as wearable electronics and bendable displays. Precise and high-performance sensors readout chips are crucial for high quality flexible electronic products. In this work, the design of a CMOS readout circuit for an array of printed strain gauges is presented. The ultra-thin readout chip and the printed sensors are combined on a thin Benzocyclobutene/Polyimide (BCB/PI) substrate to form a Hybrid System-in-Foil (HySiF), which is used as an electronic skin for robotic applications. Each strain gauge utilizes a Wheatstone bridge circuit, where four Aerosol Jet® printed meander-shaped resistors form a full-bridge topology. The readout chip amplifies the output voltage difference (about 5 mV full-scale swing) of the strain gauge. One challenge during the sensor interface circuit design is to compensate for the relatively large dc offset (about 30 mV at 1 mA) in the bridge output voltage so that the amplified signal span matches the input range of an analog-to-digital converter (ADC). The circuit design uses the 0. 5 µm mixed-signal GATEFORESTTM technology. In order to achieve the mechanical flexibility, the chip fabrication is based on either back thinned wafers or the ChipFilmTM technology, which enables the manufacturing of silicon chips with a thickness of about 20 µm. The implemented readout chip uses a supply of 5 V and includes a 5-bit digital-to-analog converter (DAC), a differential difference amplifier (DDA), and a 10-bit successive approximation register (SAR) ADC. The circuit is simulated across process, supply and temperature corners and the simulation results indicate excellent performance in terms of circuit stability and linearity.

Digital seismo-acoustic signal processing aboard a wireless sensor platform

NASA Astrophysics Data System (ADS)

Marcillo, O.; Johnson, J. B.; Lorincz, K.; Werner-Allen, G.; Welsh, M.

2006-12-01

We are developing a low power, low-cost wireless sensor array to conduct real-time signal processing of earthquakes at active volcanoes. The sensor array, which integrates data from both seismic and acoustic sensors, is based on Moteiv TMote Sky wireless sensor nodes (www.moteiv.com). The nodes feature a Texas Instruments MSP430 microcontroller, 48 Kbytes of program memory, 10 Kbytes of static RAM, 1 Mbyte of external flash memory, and a 2.4-GHz Chipcon CC2420 IEEE 802.15.4 radio. The TMote Sky is programmed in TinyOS. Basic signal processing occurs on an array of three peripheral sensor nodes. These nodes are tied into a dedicated GPS receiver node, which is focused on time synchronization, and a central communications node, which handles data integration and additional processing. The sensor nodes incorporate dual 12-bit digitizers sampling a seismic sensor and a pressure transducer at 100 samples per second. The wireless capabilities of the system allow flexible array geometry, with a maximum aperture of 200m. We have already developed the digital signal processing routines on board the Moteiv Tmote sensor nodes. The developed routines accomplish Real-time Seismic-Amplitude Measurement (RSAM), Seismic Spectral- Amplitude Measurement (SSAM), and a user-configured Short Term Averaging / Long Term Averaging (STA LTA ratio), which is used to calculate first arrivals. The processed data from individual nodes are transmitted back to a central node, where additional processing may be performed. Such processing will include back azimuth determination and other wave field analyses. Future on-board signal processing will focus on event characterization utilizing pattern recognition and spectral characterization. The processed data is intended as low bandwidth information which can be transmitted periodically and at low cost through satellite telemetry to a web server. The processing is limited by the computational capabilities (RAM, ROM) of the nodes. Nevertheless, we envision this product to be a useful tool for assessing the state of unrest at remote volcanoes.

A low-temperature ZnO nanowire ethanol gas sensor prepared on plastic substrate

NASA Astrophysics Data System (ADS)

Lin, Chih-Hung; Chang, Shoou-Jinn; Hsueh, Ting-Jen

2016-09-01

In this work, a low-temperature ZnO nanowire ethanol gas sensor was prepared on plastic substrate. The operating temperature of the ZnO nanowire ethanol gas sensor was reduced to room temperature using ultraviolet illumination. The experimental results indicate a favorable sensor response at low temperature, with the best response at 60 °C. The results also reveal that the ZnO nanowire ethanol gas sensor can be easily integrated into portable products, whose waste heat can improve sensor response and achieve energy savings, while energy consumption can be further reduced by solar irradiation.

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

2017 Guralp Affinity Digitizer Evaluation.

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

Merchant, Bion J.

Sandia National Laboratories has tested and evaluated two Guralp Affinity digitizers. The Affinity digitizers are intended to record sensor output for seismic and infrasound monitoring applications. The purpose of this digitizer evaluation is to measure the performance characteristics in such areas as power consumption, input impedance, sensitivity, full scale, self- noise, dynamic range, system noise, response, passband, and timing. The Affinity digitizers are being evaluated for potential use in the International Monitoring System (IMS) of the Comprehensive Nuclear Test-Ban-Treaty Organization (CTBTO).

Metallic-packaging fiber Bragg grating sensor based on ultrasonic welding for strain-insensitive temperature measurement

NASA Astrophysics Data System (ADS)

Zhu, Lianqing; Yang, Runtao; Zhang, Yumin; Dong, Mingli; Lou, Xiaoping

2018-04-01

In this paper, a metallic-packaging fiber Bragg grating temperature sensor characterized by a strain insensitive design is demonstrated. The sensor is fabricated by the one-step ultrasonic welding technique using type-II fiber Bragg grating combined with an aluminum alloy substrate. Finite element analysis is used to perform theoretical evaluation. The result of the experiment illustrates that the metallic-packaging temperature sensor is insensitive to longitudinal strain. The sensor's temperature sensitivity is 36 pm/°C over the range of 50-110 °C, with the correlation coefficient (R2) being 0.999. The sensor's temporal response is 40 s at a sudden temperature change from 21 °C to 100 °C. The proposed sensor can be applied on reliable and precise 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 Insertable Passive LC Pressure Sensor Based on an Alumina Ceramic for In Situ Pressure Sensing in High-Temperature Environments.

PubMed

Xiong, Jijun; Li, Chen; Jia, Pinggang; Chen, Xiaoyong; Zhang, Wendong; Liu, Jun; Xue, Chenyang; Tan, Qiulin

2015-08-31

Pressure measurements in high-temperature applications, including compressors, turbines, and others, have become increasingly critical. This paper proposes an implantable passive LC pressure sensor based on an alumina ceramic material for in situ pressure sensing in high-temperature environments. The inductance and capacitance elements of the sensor were designed independently and separated by a thermally insulating material, which is conducive to reducing the influence of the temperature on the inductance element and improving the quality factor of the sensor. In addition, the sensor was fabricated using thick film integrated technology from high-temperature materials that ensure stable operation of the sensor in high-temperature environments. Experimental results showed that the sensor accurately monitored pressures from 0 bar to 2 bar at temperatures up to 800 °C. The sensitivity, linearity, repeatability error, and hysteretic error of the sensor were 0.225 MHz/bar, 95.3%, 5.5%, and 6.2%, respectively.

An Insertable Passive LC Pressure Sensor Based on an Alumina Ceramic for In Situ Pressure Sensing in High-Temperature Environments

PubMed Central

Xiong, Jijun; Li, Chen; Jia, Pinggang; Chen, Xiaoyong; Zhang, Wendong; Liu, Jun; Xue, Chenyang; Tan, Qiulin

2015-01-01

Pressure measurements in high-temperature applications, including compressors, turbines, and others, have become increasingly critical. This paper proposes an implantable passive LC pressure sensor based on an alumina ceramic material for in situ pressure sensing in high-temperature environments. The inductance and capacitance elements of the sensor were designed independently and separated by a thermally insulating material, which is conducive to reducing the influence of the temperature on the inductance element and improving the quality factor of the sensor. In addition, the sensor was fabricated using thick film integrated technology from high-temperature materials that ensure stable operation of the sensor in high-temperature environments. Experimental results showed that the sensor accurately monitored pressures from 0 bar to 2 bar at temperatures up to 800 °C. The sensitivity, linearity, repeatability error, and hysteretic error of the sensor were 0.225 MHz/bar, 95.3%, 5.5%, and 6.2%, respectively. PMID:26334279

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

Principles and Applications of Imaging Radar, Manual of Remote Sensing, 3rd Edition, Volume 2

NASA Astrophysics Data System (ADS)

Moran, M. Susan

Aerial photographs and digital images from orbiting optical scanners are a daily source of information for the general public through newspapers, television, magazines, and posters. Such images are just as prevalent in scientific journal literature. In the last 6 months, more than half of the weekly issues of Eos published an image acquired by a remote digital sensor. As a result, most geoscientists are familiar with the characteristics and even the acronyms of the current satellites and their optical sensors, common detector filters, and image presentation. In many cases, this familiarity has bred contempt. This is so because the limitations of optical sensors (imaging in the visible and infrared portions of the electromagnetic spectrum) can be quite formidable. Images of the surface cannot be acquired through clouds, and image quality is impaired with low-light conditions (such as at polar regions), atmospheric scattering and absorption, and variations in sun/sensor/surface geometry.

Evaluation of Inter-Mountain Labs infrasound sensors : July 2007.

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

Hart, Darren M.

2007-10-01

Sandia National Laboratories has tested and evaluated three Inter Mountain Labs infrasound sensors. The test results included in this report were in response to static and tonal-dynamic input signals. Most test methodologies used were based on IEEE Standards 1057 for Digitizing Waveform Recorders and 1241 for Analog to Digital Converters; others were designed by Sandia specifically for infrasound application evaluation and for supplementary criteria not addressed in the IEEE standards. The objective of this work was to evaluate the overall technical performance of the Inter Mountain Labs (IML) infrasound sensor model SS. The results of this evaluation were only comparedmore » to relevant noise models; due to a lack of manufactures documentation notes on the sensors under test prior to testing. The tests selected for this system were chosen to demonstrate different performance aspects of the components under test.« less

Automatic Carbon Dioxide-Methane Gas Sensor Based on the Solubility of Gases in Water

PubMed Central

Cadena-Pereda, Raúl O.; Rivera-Muñoz, Eric M.; Herrera-Ruiz, Gilberto; Gomez-Melendez, Domingo J.; Anaya-Rivera, Ely K.

2012-01-01

Biogas methane content is a relevant variable in anaerobic digestion processing where knowledge of process kinetics or an early indicator of digester failure is needed. The contribution of this work is the development of a novel, simple and low cost automatic carbon dioxide-methane gas sensor based on the solubility of gases in water as the precursor of a sensor for biogas quality monitoring. The device described in this work was used for determining the composition of binary mixtures, such as carbon dioxide-methane, in the range of 0–100%. The design and implementation of a digital signal processor and control system into a low-cost Field Programmable Gate Array (FPGA) platform has permitted the successful application of data acquisition, data distribution and digital data processing, making the construction of a standalone carbon dioxide-methane gas sensor possible. PMID:23112626

Digital Analysis of Sit-to-Stand in Masters Athletes, Healthy Old People, and Young Adults Using a Depth Sensor.

PubMed

Leightley, Daniel; Yap, Moi Hoon

2018-03-02

The aim of this study was to compare the performance between young adults ( n = 15), healthy old people ( n = 10), and masters athletes ( n = 15) using a depth sensor and automated digital assessment framework. Participants were asked to complete a clinically validated assessment of the sit-to-stand technique (five repetitions), which was recorded using a depth sensor. A feature encoding and evaluation framework to assess balance, core, and limb performance using time- and speed-related measurements was applied to markerless motion capture data. The associations between the measurements and participant groups were examined and used to evaluate the assessment framework suitability. The proposed framework could identify phases of sit-to-stand, stability, transition style, and performance between participant groups with a high degree of accuracy. In summary, we found that a depth sensor coupled with the proposed framework could identify performance subtleties between groups.

Digital Analysis of Sit-to-Stand in Masters Athletes, Healthy Old People, and Young Adults Using a Depth Sensor

PubMed Central

2018-01-01

The aim of this study was to compare the performance between young adults (n = 15), healthy old people (n = 10), and masters athletes (n = 15) using a depth sensor and automated digital assessment framework. Participants were asked to complete a clinically validated assessment of the sit-to-stand technique (five repetitions), which was recorded using a depth sensor. A feature encoding and evaluation framework to assess balance, core, and limb performance using time- and speed-related measurements was applied to markerless motion capture data. The associations between the measurements and participant groups were examined and used to evaluate the assessment framework suitability. The proposed framework could identify phases of sit-to-stand, stability, transition style, and performance between participant groups with a high degree of accuracy. In summary, we found that a depth sensor coupled with the proposed framework could identify performance subtleties between groups. PMID:29498644

Automatic carbon dioxide-methane gas sensor based on the solubility of gases in water.

PubMed

Cadena-Pereda, Raúl O; Rivera-Muñoz, Eric M; Herrera-Ruiz, Gilberto; Gomez-Melendez, Domingo J; Anaya-Rivera, Ely K

2012-01-01

Biogas methane content is a relevant variable in anaerobic digestion processing where knowledge of process kinetics or an early indicator of digester failure is needed. The contribution of this work is the development of a novel, simple and low cost automatic carbon dioxide-methane gas sensor based on the solubility of gases in water as the precursor of a sensor for biogas quality monitoring. The device described in this work was used for determining the composition of binary mixtures, such as carbon dioxide-methane, in the range of 0-100%. The design and implementation of a digital signal processor and control system into a low-cost Field Programmable Gate Array (FPGA) platform has permitted the successful application of data acquisition, data distribution and digital data processing, making the construction of a standalone carbon dioxide-methane gas sensor possible.

Unattended Ground Sensors for Expeditionary Force 21 Intelligence Collections

DTIC Science & Technology

2015-06-01

tamper. 55  Size: 3 ½ x 3 ½ x 1 ¾ inches.  Wireless RF networked communications.  Built in seismic, acoustic , magnetic, and PIR sensors ...Marine Corps VHF Very High Frequency WSN Wireless Sensor Network xvi THIS PAGE INTENTIONALLY LEFT BLANK xvii ACKNOWLEDGMENTS I want...that allow digital wireless RF communications from each sensor interfaced into a variety of network architectures to relay critical data to a final

Wearable knee health rehabilitation assessment using acoustical emissions

NASA Astrophysics Data System (ADS)

Teague, Caitlin N.; Hersek, Sinan; Conant, Jordan L.; Gilliland, Scott M.; Inan, Omer T.

2017-02-01

We have developed a novel, wearable sensing system based on miniature piezoelectric contact microphones for measuring the acoustical emissions from the knee during movement. The system consists of two contact microphones, positioned on the medial and lateral sides of the patella, connected to custom, analog pre-amplifier circuits and a microcontroller for digitization and data storage on a secure digital card. Tn addition to the acoustical sensing, the system includes two integrated inertial measurement sensors including accelerometer and gyroscope modalities to enable joint angle calculations; these sensors, with digital outputs, are connected directly to the same microcontroller. The system provides low noise, accurate joint acoustical emission and angle measurements in a wearable form factor and has several hours of battery life.

An automatic analyzer of solid state nuclear track detectors using an optic RAM as image sensor

NASA Astrophysics Data System (ADS)

Staderini, Enrico Maria; Castellano, Alfredo

1986-02-01

An optic RAM is a conventional digital random access read/write dynamic memory device featuring a quartz windowed package and memory cells regularly ordered on the chip. Such a device is used as an image sensor because each cell retains data stored in it for a time depending on the intensity of the light incident on the cell itself. The authors have developed a system which uses an optic RAM to acquire and digitize images from electrochemically etched CR39 solid state nuclear track detectors (SSNTD) in the track count rate up to 5000 cm -2. On the digital image so obtained, a microprocessor, with appropriate software, performs image analysis, filtering, tracks counting and evaluation.

Low-Light Image Enhancement Using Adaptive Digital Pixel Binning

PubMed Central

Yoo, Yoonjong; Im, Jaehyun; Paik, Joonki

2015-01-01

This paper presents an image enhancement algorithm for low-light scenes in an environment with insufficient illumination. Simple amplification of intensity exhibits various undesired artifacts: noise amplification, intensity saturation, and loss of resolution. In order to enhance low-light images without undesired artifacts, a novel digital binning algorithm is proposed that considers brightness, context, noise level, and anti-saturation of a local region in the image. The proposed algorithm does not require any modification of the image sensor or additional frame-memory; it needs only two line-memories in the image signal processor (ISP). Since the proposed algorithm does not use an iterative computation, it can be easily embedded in an existing digital camera ISP pipeline containing a high-resolution image sensor. PMID:26121609

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

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...

An Integrated Thermal Compensation System for MEMS Inertial Sensors

PubMed Central

Chiu, Sheng-Ren; Teng, Li-Tao; Chao, Jen-Wei; Sue, Chung-Yang; Lin, Chih-Hsiou; Chen, Hong-Ren; Su, Yan-Kuin

2014-01-01

An active thermal compensation system for a low temperature-bias-drift (TBD) MEMS-based gyroscope is proposed in this study. First, a micro-gyroscope is fabricated by a high-aspect-ratio silicon-on-glass (SOG) process and vacuum packaged by glass frit bonding. Moreover, a drive/readout ASIC, implemented by the 0.25 μm 1P5M standard CMOS process, is designed and integrated with the gyroscope by directly wire bonding. Then, since the temperature effect is one of the critical issues in the high performance gyroscope applications, the temperature-dependent characteristics of the micro-gyroscope are discussed. Furthermore, to compensate the TBD of the micro-gyroscope, a thermal compensation system is proposed and integrated in the aforementioned ASIC to actively tune the parameters in the digital trimming mechanism, which is designed in the readout ASIC. Finally, some experimental results demonstrate that the TBD of the micro-gyroscope can be compensated effectively by the proposed compensation system. PMID:24599191

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.

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.

Method and apparatus for measuring solar radiation in a vegetative canopy

DOEpatents

Gutschick, V.P.; Barron, M.H.; Waechter, D.A.; Wolf, M.A.

1985-04-30

An apparatus and method for measuring solar radiation received in a vegetative canopy. A multiplicity of sensors selectively generates electrical signals in response to impinging photosynthetically active radiation in sunlight. Each sensor is attached to a plant within the canopy and is electrically connected to a separate port in a junction box having a multiplicity of ports. Each port is connected to an operational amplifier. Each amplifier amplifies the signals generated by the sensors. Each amplifier is connected to an analog-to-digital convertor which digitizes each signal. A computer is connected to the convertors and accumulates and stores solar radiation data. A data output device such as a printer is connected to the computer and displays the data.

Method and apparatus for measuring solar radiation in a vegetative canopy

DOEpatents

Gutschick, Vincent P.; Barron, Michael H.; Waechter, David A.; Wolf, Michael A.

1987-01-01

An apparatus and method for measuring solar radiation received in a vegetative canopy. A multiplicity of sensors selectively generates electrical signals in response to impinging photosynthetically active radiation in sunlight. Each sensor is attached to a plant within the canopy and is electrically connected to a separate port in a junction box having a multiplicity of ports. Each port is connected to an operational amplifier. Each amplifier amplifies the signals generated by the sensors. Each amplifier is connected to an analog-to-digital convertor which digitizes each signal. A computer is connected to the convertors and accumulates and stores solar radiation data. A data output device such as a printer is connected to the computer and displays the data.

Digital processing of mesoscale analysis and space sensor data

NASA Technical Reports Server (NTRS)

Hickey, J. S.; Karitani, S.

1985-01-01

The mesoscale analysis and space sensor (MASS) data management and analysis system on the research computer system is presented. The MASS data base management and analysis system was implemented on the research computer system which provides a wide range of capabilities for processing and displaying large volumes of conventional and satellite derived meteorological data. The research computer system consists of three primary computers (HP-1000F, Harris/6, and Perkin-Elmer 3250), each of which performs a specific function according to its unique capabilities. The overall tasks performed concerning the software, data base management and display capabilities of the research computer system in terms of providing a very effective interactive research tool for the digital processing of mesoscale analysis and space sensor data is described.

A safety monitoring system for taxi based on CMOS imager

NASA Astrophysics Data System (ADS)

Liu, Zhi

2005-01-01

CMOS image sensors now become increasingly competitive with respect to their CCD counterparts, while adding advantages such as no blooming, simpler driving requirements and the potential of on-chip integration of sensor, analogue circuitry, and digital processing functions. A safety monitoring system for taxi based on cmos imager that can record field situation when unusual circumstance happened is described in this paper. The monitoring system is based on a CMOS imager (OV7120), which can output digital image data through parallel pixel data port. The system consists of a CMOS image sensor, a large capacity NAND FLASH ROM, a USB interface chip and a micro controller (AT90S8515). The structure of whole system and the test data is discussed and analyzed in detail.

Online, In-Situ Monitoring Combustion Turbines Using Wireless Passive Ceramic Sensors

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

Gong, Xun; An, Linan; Xu, Chengying

2013-06-30

The overall objective of this project is to develop high-temperature wireless passive ceramic sensors for online, real-time monitoring combustion turbines. During this project period, we have successfully demonstrated temperature sensors up to 1300°C and pressure sensors up to 800°C. The temperature sensor is based on a high-Q-factor dielectric resonator and the pressure sensor utilizes the evanescent-mode cavity to realize a pressure-sensitive high-Q-factor resonator. Both sensors are efficiently integrated with a compact antenna. These sensors are wirelessly interrogated. The resonant frequency change corresponding to either temperature or pressure can be identified using a time-domain gating technique. The sensors realized in thismore » project can survive harsh environments characterized by high temperatures (>1000°C) and corrosive gases, owing to the excellent material properties of polymer-derived ceramics (PDCs) developed at University of Central Florida. It is anticipated that this work will significantly advance the capability of high-temperature sensor technologies and be of a great benefit to turbine industry and their customers.« less

An extensible, low-cost drifter control unit

NASA Astrophysics Data System (ADS)

Giudici, Andrea; Torsvik, Tomas; Soomere, Tarmo

2017-04-01

We introduce an extensible, low-cost drifter control unit, which is developed for use with surface drifters that are deployed in inland water bodies or near-coast regions. The control unit is custom-built on top of a small footprint micro controller. It makes use of a GPS receiver for position tracking, a GSM radio for data transmission, and two sensor buses to handle analog and digital data measured by an array of external sensors. A cloud-based data collection platform receives and stores the data transmitted over GPRS from the drifter. The control unit was found to perform satisfactorily in operational testing, providing data at sub-Hz frequency for position and temperature during extended time. Test deployments revealed some issues related to power consumption spikes. Even though the unit is fully functional in the present form and shows, on average, low energy consumption , battery packs with relatively large maximum output power are required to ensure its operation within prolonged periods of time. We expect that a further development of the power supply unit together with a careful de-synchronization scheme of sensors' operation would smooth those peaks without any loss of the quality of recorded information.

A Field-Scale Sensor Network Data Set for Monitoring and Modeling the Spatial and Temporal Variation of Soil Water Content in a Dryland Agricultural Field

NASA Astrophysics Data System (ADS)

Gasch, C. K.; Brown, D. J.; Campbell, C. S.; Cobos, D. R.; Brooks, E. S.; Chahal, M.; Poggio, M.

2017-12-01

We describe a soil water content monitoring data set and auxiliary data collected at a 37 ha experimental no-till farm in the Northwestern United States. Water content measurements have been compiled hourly since 2007 by ECH2O-TE and 5TE sensors installed at 42 locations and five depths (0.3, 0.6, 0.9, 1.2, and 1.5 m, 210 sensors total) across the R.J. Cook Agronomy Farm, a Long-Term Agro-Ecosystem Research Site stationed on complex terrain in a Mediterranean climate. In addition to soil water content readings, the data set includes hourly and daily soil temperature readings, annual crop histories, a digital elevation model, Bt horizon maps, seasonal apparent electrical conductivity, soil texture, and soil bulk density. Meteorological records are also available for this location. We discuss the unique challenges of maintaining the network on an operating farm and demonstrate the nature and complexity of the soil water content data. This data set is accessible online through the National Agriculture Library, has been assigned a DOI, and will be maintained for the long term.

Development of an instrumentation system for measurement of degradation of lubricating oil using optical fiber sensor

NASA Astrophysics Data System (ADS)

Laskar, S.; Bordoloi, S.

2016-01-01

This paper presents an instrumentation system to measure the degradation in lubricating oil using a bare, tapered and bent multi-mode optical fiber (BTBMOF) sensor probe and a temperature probe. The sensor system consists of (i) a bare, tapered and bent multi-mode optical fiber (BTBMOF) as optical sensor along with a laser source and a LDR (Light Dependent Resistor) as detector (ii) a temperature sensor (iii) a ATmega microcontroller based data acquisition system and (iv) a trained ANN for processing and calibration. The BTBMOF sensor and the temperature sensor are used to provide the measure of refractive index (RI) and the temperature of a lubricating oil sample. A microcontroller based instrumentation system with trained ANN algorithm has been developed to determine the degradation of the lubricating oil sample by sampling the readings of the optical fiber sensor, and the temperature sensor.

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 highest operation temperature up to 750°C, first distributed chemical measurements at the record high temperature up to 700°C, first distributed pressure measurement at the record high temperature up to 800°C, and the fiber laser sensors with the record high operation temperature up to 700°C. The research performed by this program dramatically expand the functionality, adaptability, and applicability of distributed fiber optical sensors with potential applications in a number of high-temperature energy systems such as fossil-fuel power generation, high-temperature fuel cell applications, and potential for nuclear energy systems.« less

The Dram As An X-Ray Sensor

NASA Astrophysics Data System (ADS)

Jacobs, Alan M.; Cox, John D.; Juang, Yi-Shung

1987-01-01

A solid-state digital x-ray detector is described which can replace high resolution film in industrial radiography and has potential for application in some medical imaging. Because of the 10 micron pixel pitch on the sensor, contact magnification radiology is possible and is demonstrated. Methods for frame speed increase and integration of sensor to a large format are discussed.

A Research Program in Computer Technology. Volume 1

DTIC Science & Technology

1981-08-01

rigidity, sensor networks 10. command and control, digital voice communication, graphic input device for terminal, multimedia communications, portable...satellite channel in the internetwork environment; Distributed Sensor Networks - formulation of algorithms and communication protocols to support the...operation of geographically distributed sensors ; Personal Communicator - work intended to result in a demonstration-level portable terminal to test and

Fiber Optic Geophysics Sensor Array

NASA Astrophysics Data System (ADS)

Grochowski, Lucjan

1989-01-01

The distributed optical sensor arrays are analysed in view of specific needs of 3-D seismic explorations methods. There are compared advantages and disadventages of arrays supported by the sensors which are modulated in intensity and phase. In these systems all-fiber optic structures and their compabilities with digital geophysic formats are discussed. It was shown that the arrays based on TDM systems with the intensity modulated sensors are economically and technically the best matched for geophysic systems supported by a large number of the sensors.

Leap Frog Digital Sensors and Definition, Integration & Testing FY 2003 Annual Report

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

Meitzler, Wayne D.; Ouderkirk, Steven J.; Shoemaker, Steven V.

2003-12-31

The objective of Leap Frog is to develop a comprehensive security tool that is transparent to the user community and more effective than current methods for preventing and detecting security compromises of critical physical and digital assets. Current security tools intrude on the people that interact with these critical assets by requiring them to perform additional functions or having additional visible sensors. Leap Frog takes security to the next level by being more effective and reducing the adverse impact on the people interacting with protected assets.

Infrared-Proximity-Sensor Modules For Robot

NASA Technical Reports Server (NTRS)

Parton, William; Wegerif, Daniel; Rosinski, Douglas

1995-01-01

Collision-avoidance system for articulated robot manipulators uses infrared proximity sensors grouped together in array of sensor modules. Sensor modules, called "sensorCells," distributed processing board-level products for acquiring data from proximity-sensors strategically mounted on robot manipulators. Each sensorCell self-contained and consists of multiple sensing elements, discrete electronics, microcontroller and communications components. Modules connected to central control computer by redundant serial digital communication subsystem including both serial and a multi-drop bus. Detects objects made of various materials at distance of up to 50 cm. For some materials, such as thermal protection system tiles, detection range reduced to approximately 20 cm.

Harsh-environment fiber optic sensors for structural monitoring applications

NASA Astrophysics Data System (ADS)

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

2004-07-01

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 a pressure sensor to 100psi at a gas temperature of 800°C, calibration of an accelerometer to 2.5g at a substrate temperature of 850°C. Temperature sensors have been field tested up to 1400°C, and a skin friction sensor designed for 870°C operation has been constructed. 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.

Compact, Miniature MMIC Receiver Modules for an MMIC Array Spectrograph

NASA Technical Reports Server (NTRS)

Kangaslahti, Pekka P.; Gaier, Todd C.; Cooperrider, Joelle T.; Samoska, Lorene A.; Soria, Mary M.; ODwyer, Ian J.; Weinreb, Sander; Custodero, Brian; Owen, Heahter; Grainge, Keith;

A Fully Transparent Flexible Sensor for Cryogenic Temperatures Based on High Strength Metallurgical Graphene

PubMed Central

Pawlak, Ryszard; Lebioda, Marcin; Rymaszewski, Jacek; Szymanski, Witold; Kolodziejczyk, Lukasz; Kula, Piotr

2016-01-01

Low-temperature electronics operating in below zero temperatures or even below the lower limit of the common −65 to 125 °C temperature range are essential in medical diagnostics, in space exploration and aviation, in processing and storage of food and mainly in scientific research, like superconducting materials engineering and their applications—superconducting magnets, superconducting energy storage, and magnetic levitation systems. Such electronic devices demand special approach to the materials used in passive elements and sensors. The main goal of this work was the implementation of a fully transparent, flexible cryogenic temperature sensor with graphene structures as sensing element. Electrodes were made of transparent ITO (Indium Tin Oxide) or ITO/Ag/ITO conductive layers by laser ablation and finally encapsulated in a polymer coating. A helium closed-cycle cryostat has been used in measurements of the electrical properties of these graphene-based temperature sensors under cryogenic conditions. The sensors were repeatedly cooled from room temperature to cryogenic temperature. Graphene structures were characterized using Raman spectroscopy. The observation of the resistance changes as a function of temperature indicates the potential use of graphene layers in the construction of temperature sensors. The temperature characteristics of the analyzed graphene sensors exhibit no clear anomalies or strong non-linearity in the entire studied temperature range (as compared to the typical carbon sensor). PMID:28036036

A Fully Transparent Flexible Sensor for Cryogenic Temperatures Based on High Strength Metallurgical Graphene.

PubMed

Pawlak, Ryszard; Lebioda, Marcin; Rymaszewski, Jacek; Szymanski, Witold; Kolodziejczyk, Lukasz; Kula, Piotr

2016-12-28

Low-temperature electronics operating in below zero temperatures or even below the lower limit of the common -65 to 125 °C temperature range are essential in medical diagnostics, in space exploration and aviation, in processing and storage of food and mainly in scientific research, like superconducting materials engineering and their applications-superconducting magnets, superconducting energy storage, and magnetic levitation systems. Such electronic devices demand special approach to the materials used in passive elements and sensors. The main goal of this work was the implementation of a fully transparent, flexible cryogenic temperature sensor with graphene structures as sensing element. Electrodes were made of transparent ITO (Indium Tin Oxide) or ITO/Ag/ITO conductive layers by laser ablation and finally encapsulated in a polymer coating. A helium closed-cycle cryostat has been used in measurements of the electrical properties of these graphene-based temperature sensors under cryogenic conditions. The sensors were repeatedly cooled from room temperature to cryogenic temperature. Graphene structures were characterized using Raman spectroscopy. The observation of the resistance changes as a function of temperature indicates the potential use of graphene layers in the construction of temperature sensors. The temperature characteristics of the analyzed graphene sensors exhibit no clear anomalies or strong non-linearity in the entire studied temperature range (as compared to the typical carbon sensor).

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.

Sensing Properties of a Novel Temperature Sensor Based on Field Assisted Thermal Emission.

PubMed

Pan, Zhigang; Zhang, Yong; Cheng, Zhenzhen; Tong, Jiaming; Chen, Qiyu; Zhang, Jianpeng; Zhang, Jiaxiang; Li, Xin; Li, Yunjia

2017-02-27

The existing temperature sensors using carbon nanotubes (CNTs) are limited by low sensitivity, complicated processes, or dependence on microscopy to observe the experimental results. Here we report the fabrication and successful testing of an ionization temperature sensor featuring non-self-sustaining discharge. The sharp tips of nanotubes generate high electric fields at relatively low voltages, lowering the work function of electrons emitted by CNTs, and thereby enabling the safe operation of such sensors. Due to the temperature effect on the electron emission of CNTs, the collecting current exhibited an exponential increase with temperature rising from 20 °C to 100 °C. Additionally, a higher temperature coefficient of 0.04 K -1 was obtained at 24 V voltage applied on the extracting electrode, higher than the values of other reported CNT-based temperature sensors. The triple-electrode ionization temperature sensor is easy to fabricate and converts the temperature change directly into an electrical signal. It shows a high temperature coefficient and good application potential.

Sensing Properties of a Novel Temperature Sensor Based on Field Assisted Thermal Emission

PubMed Central

Pan, Zhigang; Zhang, Yong; Cheng, Zhenzhen; Tong, Jiaming; Chen, Qiyu; Zhang, Jianpeng; Zhang, Jiaxiang; Li, Xin; Li, Yunjia

2017-01-01

The existing temperature sensors using carbon nanotubes (CNTs) are limited by low sensitivity, complicated processes, or dependence on microscopy to observe the experimental results. Here we report the fabrication and successful testing of an ionization temperature sensor featuring non-self-sustaining discharge. The sharp tips of nanotubes generate high electric fields at relatively low voltages, lowering the work function of electrons emitted by CNTs, and thereby enabling the safe operation of such sensors. Due to the temperature effect on the electron emission of CNTs, the collecting current exhibited an exponential increase with temperature rising from 20 °C to 100 °C. Additionally, a higher temperature coefficient of 0.04 K−1 was obtained at 24 V voltage applied on the extracting electrode, higher than the values of other reported CNT-based temperature sensors. The triple-electrode ionization temperature sensor is easy to fabricate and converts the temperature change directly into an electrical signal. It shows a high temperature coefficient and good application potential. PMID:28264427

Design of a WSN for the Sampling of Environmental Variability in Complex Terrain

PubMed Central

Martín-Tardío, Miguel A.; Felicísimo, Ángel M.

2014-01-01

In-situ environmental parameter measurements using sensor systems connected to a wireless network have become widespread, but the problem of monitoring large and mountainous areas by means of a wireless sensor network (WSN) is not well resolved. The main reasons for this are: (1) the environmental variability distribution is unknown in the field; (2) without this knowledge, a huge number of sensors would be necessary to ensure the complete coverage of the environmental variability and (3) WSN design requirements, for example, effective connectivity (intervisibility), limiting distances and controlled redundancy, are usually solved by trial and error. Using temperature as the target environmental variable, we propose: (1) a method to determine the homogeneous environmental classes to be sampled using the digital elevation model (DEM) and geometric simulations and (2) a procedure to determine an effective WSN design in complex terrain in terms of the number of sensors, redundancy, cost and spatial distribution. The proposed methodology, based on geographic information systems and binary integer programming can be easily adapted to a wide range of applications that need exhaustive and continuous environmental monitoring with high spatial resolution. The results show that the WSN design is perfectly suited to the topography and the technical specifications of the sensors, and provides a complete coverage of the environmental variability in terms of Sun exposure. However these results still need be validated in the field and the proposed procedure must be refined. PMID:25412218

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.

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.

Fiber-optic miniature sensor for in situ temperature monitoring of curing composite material

NASA Astrophysics Data System (ADS)

Sampath, Umesh; Kim, Dae-gil; Kim, Hyunjin; Song, Minho

2018-04-01

This study proposes a fiber-optic temperature sensor with a single-mode fiber tip covered with a thermo-sensitive polymer resin. The temperature is sensed by measuring the Fresnel reflection from the optical fiber/polymer interface. Because the thermo-optic coefficients differ between the optical fiber and the polymer, the in situ temperature can be measured even in curing composite materials. In initial experiments, the proposed sensor successfully measured and recovered the temperature information. The measured sensor data were linearly correlated, with an R2 exceeding 0.99. The standard deviation in the long-term measurements of constant temperature was 2.6%. The durability and stability of the sensor head material in long-term operation was validated by Fourier transform infrared spectroscopy and X-ray diffraction analysis. In further experiments, the suggested miniature temperature sensor obtained the internal temperatures of curing composite material over a wide range (30-110 °C).

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

How to create a very-low-cost, very-low-power, credit-card-sized and real-time-ready datalogger

NASA Astrophysics Data System (ADS)

Bès de Berc, M.; Grunberg, M.; Engels, F.

2015-03-01

In order to improve an existing network, a field seismologist would have to add some extra sensors to a remote station. However, additional ADCs (analogue-to-digital converters) are not always implemented on commercial dataloggers, or, if they are, they may already be used. Installing additional ADCs often implies an expensive development, or the purchase of a new datalogger. We present here a simple method to take advantage of the ADCs of an embedded computer in order to create data in a seismological standard format and integrate them within the real-time data stream from the station. Our first goal is to plug temperature and pressure sensors on the ADCs, read data and record them in mini-seed format (seed stands for Standard for the Exchange of the Earthquake Data), and eventually transfer them to a central server together with the seismic data, by using seedlink, since mini-seed and seedlink are standard for seismology.

Tuning the Solar Dynamics Observatory Onboard Kalman Filter

NASA Technical Reports Server (NTRS)

Halverson, Julie Kay; Harman, Rick; Carpenter, Russell; Poland, Devin

2017-01-01

The Solar Dynamics Observatory (SDO) was launched in 2010. SDO is a sun pointing semi-autonomous spacecraft in a geosynchronous orbit that allows nearly continuous observations of the sun. SDO is equipped with coarse sun sensors, two star trackers, a digital sun sensor, and three two-axis inertial reference units (IRU). The IRUs are temperature sensitive and were designed to operate in a stable thermal environment. Due to battery degradation concerns the IRU heaters were not used on SDO and the onboard filter was tuned to accommodate the noisier IRU data. Since launch currents have increased on two IRUs, one had to eventually be powered off. Recent ground tests on a battery similar to SDO indicated the heaters would have negligible impact on battery degradation, so in 2016 a decision was made to turn the heaters on. This paper presents the analysis and results of updating the filter tuning parameters onboard SDO with the IRUs now operating in their intended thermal environment.

Brief Communication: A low-cost Arduino®-based wire extensometer for earth flow monitoring

NASA Astrophysics Data System (ADS)

Guerriero, Luigi; Guerriero, Giovanni; Grelle, Gerardo; Guadagno, Francesco M.; Revellino, Paola

2017-06-01

Continuous monitoring of earth flow displacement is essential for the understanding of the dynamic of the process, its ongoing evolution and designing mitigation measures. Despite its importance, it is not always applied due to its expense and the need for integration with additional sensors to monitor factors controlling movement. To overcome these problems, we developed and tested a low-cost Arduino-based wire-rail extensometer integrating a data logger, a power system and multiple digital and analog inputs. The system is equipped with a high-precision position transducer that in the test configuration offers a measuring range of 1023 mm and an associated accuracy of ±1 mm, and integrates an operating temperature sensor that should allow potential thermal drift that typically affects this kind of systems to be identified and corrected. A field test, conducted at the Pietrafitta earth flow where additional monitoring systems had been installed, indicates a high reliability of the measurement and a high monitoring stability without visible thermal drift.

Automatic aeroponic irrigation system based on Arduino’s platform

NASA Astrophysics Data System (ADS)

Montoya, A. P.; Obando, F. A.; Morales, J. G.; Vargas, G.

2017-06-01

The recirculating hydroponic culture techniques, as aeroponics, has several advantages over traditional agriculture, aimed to improve the efficiently and environmental impact of agriculture. These techniques require continuous monitoring and automation for proper operation. In this work was developed an automatic monitored aeroponic-irrigation system based on the Arduino’s free software platform. Analog and digital sensors for measuring the temperature, flow and level of a nutrient solution in a real greenhouse were implemented. In addition, the pH and electric conductivity of nutritive solutions are monitored using the Arduino’s differential configuration. The sensor network, the acquisition and automation system are managed by two Arduinos modules in master-slave configuration, which communicate one each other wireless by Wi-Fi. Further, data are stored in micro SD memories and the information is loaded on a web page in real time. The developed device brings important agronomic information when is tested with an arugula culture (Eruca sativa Mill). The system also could be employ as an early warning system to prevent irrigation malfunctions.

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 silicon substrate temperature if never exposed to temperatures above about 220 °C. PMID:26989603

Evaluating RGB photogrammetry and multi-temporal digital surface models for detecting soil erosion

NASA Astrophysics Data System (ADS)

Anders, Niels; Keesstra, Saskia; Seeger, Manuel

2013-04-01

Photogrammetry is a widely used tool for generating high-resolution digital surface models. Unmanned Aerial Vehicles (UAVs), equipped with a Red Green Blue (RGB) camera, have great potential in quickly acquiring multi-temporal high-resolution orthophotos and surface models. Such datasets would ease the monitoring of geomorphological processes, such as local soil erosion and rill formation after heavy rainfall events. In this study we test a photogrammetric setup to determine data requirements for soil erosion studies with UAVs. We used a rainfall simulator (5 m2) and above a rig with attached a Panasonic GX1 16 megapixel digital camera and 20mm lens. The soil material in the simulator consisted of loamy sand at an angle of 5 degrees. Stereo pair images were taken before and after rainfall simulation with 75-85% overlap. Acquired images were automatically mosaicked to create high-resolution orthorectified images and digital surface models (DSM). We resampled the DSM to different spatial resolutions to analyze the effect of cell size to the accuracy of measured rill depth and soil loss estimations, and determined an optimal cell size (thus flight altitude). Furthermore, the high spatial accuracy of the acquired surface models allows further analysis of rill formation and channel initiation related to e.g. surface roughness. We suggest implementing near-infrared and temperature sensors to combine soil moisture and soil physical properties with surface morphology for future investigations.

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.

40 CFR 63.5995 - What are my monitoring installation, operation, and maintenance requirements?

Code of Federal Regulations, 2010 CFR

2010-07-01

... paragraphs (a) and (b)(1) through (8) of this section. (1) Locate the temperature sensor in a position that provides a representative temperature. (2) For a non-cryogenic temperature range, use a temperature sensor... value, whichever is larger. (3) For a cryogenic temperature range, use a temperature sensor with a...

40 CFR 63.5725 - What are the requirements for monitoring and demonstrating continuous compliance?

Code of Federal Regulations, 2012 CFR

2012-07-01

... temperature monitoring device. (i) Locate the temperature sensor in a position that provides a representative temperature. (ii) Use a temperature sensor with a minimum tolerance of 2.2 °C or 0.75 percent of the temperature value, whichever is larger. (iii) Shield the temperature sensor system from electromagnetic...

40 CFR 63.5725 - What are the requirements for monitoring and demonstrating continuous compliance?

Code of Federal Regulations, 2010 CFR

2010-07-01

... temperature monitoring device. (i) Locate the temperature sensor in a position that provides a representative temperature. (ii) Use a temperature sensor with a minimum tolerance of 2.2 °C or 0.75 percent of the temperature value, whichever is larger. (iii) Shield the temperature sensor system from electromagnetic...

40 CFR 63.5725 - What are the requirements for monitoring and demonstrating continuous compliance?

Code of Federal Regulations, 2011 CFR

2011-07-01

... temperature monitoring device. (i) Locate the temperature sensor in a position that provides a representative temperature. (ii) Use a temperature sensor with a minimum tolerance of 2.2 °C or 0.75 percent of the temperature value, whichever is larger. (iii) Shield the temperature sensor system from electromagnetic...

Comparison of tympanic and rectal temperature in febrile patients.

PubMed

Sehgal, Arvind; Dubey, N K; Jyothi, M C; Jain, Shilpa

2002-04-01

To compare tympanic membrane temperature and rectal temperature in febrile pediatric patients. Sixty febrile children were enrolled as continuous enrollment at initial triage. Two readings of ear temperature were taken in each child with Thermoscan infrared thermometer. Rectal temperature was recorded by a digital electronic thermometer. Comparison of both the techniques was done and co-relation co-efficients calculated. Parental preference for both techniques was assessed. It was observed that mean ear temperature was 38.9+/-0.90 C and that for rectal temperature was 38.8+/-0.80 degrees C. The correlation coefficient between the two was 0.994 (p < 0.01). Coefficients for both sites were comparable over a wide age range. The difference between readings taken from two ears was not significant. Temperature ranges over which readings were recorded were quite wide for both techniques. Parental preference for tympanic thermometry over rectal thermometry was noticed. Tympanic thermometry utilizes pyro-electric sensors, to detect infra-red rays emitted from the surface of tympanic membrane. Ear temperatures correlates well with rectal temperatures which have long been considered as "core" temperatures. Parents prefer the technique of ear thermometry which is quick (2 sec), safe and non-invasive and patient resistance for this is also less. A non-invasive, non-mucous device which is accurate over a wide range of temperature could be very useful.

Digital adaptive optics line-scanning confocal imaging system.

PubMed

Liu, Changgeng; Kim, Myung K

2015-01-01

A digital adaptive optics line-scanning confocal imaging (DAOLCI) system is proposed by applying digital holographic adaptive optics to a digital form of line-scanning confocal imaging system. In DAOLCI, each line scan is recorded by a digital hologram, which allows access to the complex optical field from one slice of the sample through digital holography. This complex optical field contains both the information of one slice of the sample and the optical aberration of the system, thus allowing us to compensate for the effect of the optical aberration, which can be sensed by a complex guide star hologram. After numerical aberration compensation, the corrected optical fields of a sequence of line scans are stitched into the final corrected confocal image. In DAOLCI, a numerical slit is applied to realize the confocality at the sensor end. The width of this slit can be adjusted to control the image contrast and speckle noise for scattering samples. DAOLCI dispenses with the hardware pieces, such as Shack–Hartmann wavefront sensor and deformable mirror, and the closed-loop feedbacks adopted in the conventional adaptive optics confocal imaging system, thus reducing the optomechanical complexity and cost. Numerical simulations and proof-of-principle experiments are presented that demonstrate the feasibility of this idea.