Effects of radiation and temperature on gallium nitride (GaN) metal-semiconductor-metal ultraviolet photodetectors

NASA Astrophysics Data System (ADS)

Chiamori, Heather C.; Angadi, Chetan; Suria, Ateeq; Shankar, Ashwin; Hou, Minmin; Bhattacharya, Sharmila; Senesky, Debbie G.

2014-06-01

The development of radiation-hardened, temperature-tolerant materials, sensors and electronics will enable lightweight space sub-systems (reduced packaging requirements) with increased operation lifetimes in extreme harsh environments such as those encountered during space exploration. Gallium nitride (GaN) is a ceramic, semiconductor material stable within high-radiation, high-temperature and chemically corrosive environments due to its wide bandgap (3.4 eV). These material properties can be leveraged for ultraviolet (UV) wavelength photodetection. In this paper, current results of GaN metal-semiconductor-metal (MSM) UV photodetectors behavior after irradiation up to 50 krad and temperatures of 15°C to 150°C is presented. These initial results indicate that GaN-based sensors can provide robust operation within extreme harsh environments. Future directions for GaN-based photodetector technology for down-hole, automotive and space exploration applications are also discussed.

A monitor for the laboratory evaluation of control integrity in digital control systems operating in harsh electromagnetic environments

NASA Technical Reports Server (NTRS)

Belcastro, Celeste M.; Fischl, Robert; Kam, Moshe

1992-01-01

This paper presents a strategy for dynamically monitoring digital controllers in the laboratory for susceptibility to electromagnetic disturbances that compromise control integrity. The integrity of digital control systems operating in harsh electromagnetic environments can be compromised by upsets caused by induced transient electrical signals. Digital system upset is a functional error mode that involves no component damage, can occur simultaneously in all channels of a redundant control computer, and is software dependent. The motivation for this work is the need to develop tools and techniques that can be used in the laboratory to validate and/or certify critical aircraft controllers operating in electromagnetically adverse environments that result from lightning, high-intensity radiated fields (HIRF), and nuclear electromagnetic pulses (NEMP). The detection strategy presented in this paper provides dynamic monitoring of a given control computer for degraded functional integrity resulting from redundancy management errors, control calculation errors, and control correctness/effectiveness errors. In particular, this paper discusses the use of Kalman filtering, data fusion, and statistical decision theory in monitoring a given digital controller for control calculation errors.

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.

Designing a ruggedisation lab to characterise materials for harsh environments.

PubMed

Frazzette, Nicholas; Jethva, Janak; Mehta, Khanjan; Stapleton, Joshua J; Randall, Clive

Designing products for use in developing countries presents a unique set of challenges including harsh operating environments, costly repairs and maintenance, and users with varying degrees of education and device familiarity. For products to be robust, adaptable and durable, they need to be ruggedised for environmental factors such as high temperature and humidity as well as different operational conditions such as shock and chemical exposure. The product characterisation and ruggedisation processes require specific expertise and resources that are seldom available outside of large corporations and elite national research labs. There is no standardised process since product needs strongly depend on the context and user base, making it particularly onerous for underfunded start-ups and academic groups. Standardised protocols that identify essential lab testing regimens for specific contexts and user groups can complement field-testing and accelerate the product development process while reducing costs. This article synthesises current methods and strategies for product testing employed by large corporations as well as defence-related entities. A technological and organisational framework for a service-for-fee product characterisation and ruggedisation lab that reduces costs and shortens the timespan from product invention to commercial launch in harsh settings is presented.

Micro-Structured Sapphire Fiber Sensors for Simultaneous Measurements of High-T and Dynamic Gas Pressure in Harsh Environments

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

Xiao, Hai; Tsai, Hai-Lung; Dong, Junhang

2014-09-30

This is the final report for the program “Micro-Structured Sapphire Fiber Sensors for Simultaneous Measurements of High Temperature and Dynamic Gas Pressure in Harsh Environments”, funded by NETL, and performed by Missouri University of Science and Technology, Clemson University and University of Cincinnati from October 1, 2009 to September 30, 2014. Securing a sustainable energy economy by developing affordable and clean energy from coal and other fossil fuels is a central element to the mission of The U.S. Department of Energy’s (DOE) National Energy Technology Laboratory (NETL). To further this mission, NETL funds research and development of novel sensor technologiesmore » that can function under the extreme operating conditions often found in advanced power systems. The main objective of this research program is to conduct fundamental and applied research that will lead to successful development and demonstration of robust, multiplexed, microstructured silica and single-crystal sapphire fiber sensors to be deployed into the hot zones of advanced power and fuel systems for simultaneous measurements of high temperature and gas pressure. The specific objectives of this research program include: 1) Design, fabrication and demonstration of multiplexed, robust silica and sapphire fiber temperature and dynamic gas pressure sensors that can survive and maintain fully operational in high-temperature harsh environments. 2) Development and demonstration of a novel method to demodulate the multiplexed interferograms for simultaneous measurements of temperature and gas pressure in harsh environments. 3) Development and demonstration of novel sapphire fiber cladding and low numerical aperture (NA) excitation techniques to assure high signal integrity and sensor robustness.« less

SiC-based neutron detector in quasi-realistic working conditions: efficiency and stability at room and high temperature under fast neutron irradiations

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

Ferone, Raffaello; Issa, Fatima; Ottaviani, Laurent

In the framework of the European I SMART project, we have designed and made new SiC-based nuclear radiation detectors able to operate in harsh environments and to detect both fast and thermal neutrons. In this paper, we report experimental results of fast neutron irradiation campaign at high temperature (106 deg. C) in quasi-realistic working conditions. Our device does not suffer from high temperature, and spectra do show strong stability, preserving features. These experiments, as well as others in progress, show the I SMART SiC-based device skills to operate in harsh environments, whereas other materials would strongly suffer from degradation. Workmore » is still demanded to test our device at higher temperatures and to enhance efficiency in order to make our device fully exploitable from an industrial point of view. (authors)« less

Harsh environment sensor development for advanced energy systems

NASA Astrophysics Data System (ADS)

Romanosky, Robert R.; Maley, Susan M.

2013-05-01

Highly efficient, low emission power systems have extreme conditions of high temperature, high pressure, and corrosivity that require monitoring. Sensing in these harsh environments can provide key information that directly impacts process control and system reliability. To achieve the goals and demands of clean energy, the conditions under which fossil fuels are converted into heat and power are harsh compared to traditional combustion/steam cycles. Temperatures can extend as high as 1600 Celsius (°C) in certain systems and pressures can reach as high as 5000 pounds per square inch (psi)/340 atmospheres (atm). The lack of suitable measurement technology serves as a driver for the innovations in harsh environment sensor development. Two major considerations in the development of harsh environments sensors are the materials used for sensing and the design of the sensing device. This paper will highlight the U.S. Department of Energy's, Office of Fossil Energy and National Energy Technology Laboratory's Program in advanced sensing concepts that are aimed at addressing the technology needs and drivers through the development of new sensor materials and designs capable of withstanding harsh environment conditions. Recent developments with harsh environment sensors will be highlighted and future directions towards in advanced sensing will be introduced.

Harsh environments and the evolution of multi-player cooperation.

PubMed

De Jaegher, Kris

2017-02-01

The game-theoretic model in this paper provides micro-foundations for the effect a harsher environment on the probability of cooperation among multiple players. The harshness of the environment is alternatively measured by the degree of complementarity between the players' cooperative efforts in producing a public good, and by the number of attacks on an existing public good that the players can collectively defend, where it is shown that these two measures of the degree of adversity facing the players operate in a similar fashion. We show that the effect of the degree of adversity on the probability of cooperation is monotonous, and has an opposite sign for smaller and for larger cooperation costs. For intermediate cooperation costs, we show that the effect of a harsher environment on the probability of cooperation is hill-shaped. Copyright © 2016 Elsevier Inc. All rights reserved.

Optical mounts for harsh environments

NASA Astrophysics Data System (ADS)

Mimovich, Mark E.; Griffee, Jonathan C.; Goodding, James C.

2009-08-01

Development and testing of a lightweight-kinematic optical mount with integrated passive vibration-and-shock mitigation technologies and simple / robust optical alignment functionality is presented. Traditionally, optical mounts are designed for use in laboratory environments where the thermal-mechanical environments are carefully controlled to preserve beam path conditions and background disturbances are minimized to facilitate precise optically based measurements. Today's weapon and surveillance systems, however, have optical sensor suites where static and dynamic alignment performance in the presence of harsh operating environments is required to nearly the same precision and where the system cannot afford the mass of laboratory-grade stabilized mounting systems. Jitter and alignment stability is particularly challenging for larger optics operating within moving vehicles and aircraft where high shock and significant temperature excursions occur. The design intent is to have the mount be suitable for integration into existing defense and security optical systems while also targeting new commercial and military components for improved structural dynamic and thermal distortion performance. A mount suitable for moderate-sized optics and an integrated disturbance-optical metrology system are described. The mount design has performance enhancements derived from the integration of proven aerospace mechanical vibration and shock mitigation technologies (i.e. multi-axis passive isolation and integral damping), precision alignment adjustment and lock-out functionality, high dimensional stability materials and design practices which provide benign optical surface figure errors under harsh thermal-mechanical loading. Optical jitter, alignment, and wave-front performance testing of an eight-inch-aperture optical mount based on this design approach are presented to validate predicted performance improvements over an existing commercial off-the-shelf (COTS) design.

Evaluation of Silicon-on-Insulator HTOP-01 Operational Amplifier for Wide Temperature Operation

NASA Technical Reports Server (NTRS)

Patterson, Richard; Hammoud, Ahmad; Elbuluk, Malik

2008-01-01

Electronics capable of operation under extreme temperatures are required in many of NASA space exploration missions. Aerospace and military applications, as well as some terrestrial industries constitute environments where electronic systems are anticipated to be exposed to extreme temperatures and wide-range thermal swings. Electronics that are able to withstand and operate efficiently in such harsh environments would simplify, if not eliminate, traditional thermal control elements and their associated structures for proper ambient operation. As a result, overall system mass would be reduced, design would be simplified, and reliability would be improved. Electronic parts that are built utilizing silicon-on-insulator (SOI) technology are known to offer better radiation-tolerance compared to their conventional silicon counterparts, provide faster switching, and consume less power. They also exhibit reduced leakage current and, thus, they are often tailored for high temperature operation. These attributes make SOI-based devices suitable for use in harsh environments where extreme temperatures and wide thermal swings are anticipated. A new operational amplifier, based on silicon-on-insulator technology and geared for high temperature well-logging applications, was recently introduced by Honeywell Corporation. This HTOP-01 dual precision operational amplifier is a low power device, operates on a single supply, and has an internal oscillator and an external clocking option [1]. It is rated for operation from -55 C to +225 C with a maximum output current capability of 50 mA. The amplifier chip is designed as a 14-pin, hermetically-sealed device in a ceramic package. Table I shows some of the device manufacturer s specifications.

Formulation of a strategy for monitoring control integrity in critical digital control systems

NASA Technical Reports Server (NTRS)

Belcastro, Celeste M.; Fischl, Robert; Kam, Moshe

1991-01-01

Advanced aircraft will require flight critical computer systems for stability augmentation as well as guidance and control that must perform reliably in adverse, as well as nominal, operating environments. Digital system upset is a functional error mode that can occur in electromagnetically harsh environments, involves no component damage, can occur simultaneously in all channels of a redundant control computer, and is software dependent. A strategy is presented for dynamic upset detection to be used in the evaluation of critical digital controllers during the design and/or validation phases of development. Critical controllers must be able to be used in adverse environments that result from disturbances caused by an electromagnetic source such as lightning, high intensity radiated field (HIRF), and nuclear electromagnetic pulses (NEMP). The upset detection strategy presented provides dynamic monitoring of a given control computer for degraded functional integrity that can result from redundancy management errors and control command calculation error that could occur in an electromagnetically harsh operating environment. The use is discussed of Kalman filtering, data fusion, and decision theory in monitoring a given digital controller for control calculation errors, redundancy management errors, and control effectiveness.

SiC Integrated Circuits for Power Device Drivers Able to Operate in Harsh Environments

NASA Astrophysics Data System (ADS)

Godignon, P.; Alexandru, M.; Banu, V.; Montserrat, J.; Jorda, X.; Vellvehi, M.; Schmidt, B.; Michel, P.; Millan, J.

2014-08-01

The currently developed SiC electronic devices are more robust to high temperature operation and radiation exposure damage than correspondingly rated Si ones. In order to integrate the existent SiC high power and high temperature electronics into more complex systems, a SiC integrated circuit (IC) technology capable of operation at temperatures substantially above the conventional ones is required. Therefore, this paper is a step towards the development of ICs-control electronics that have to attend the harsh environment power applications. Concretely, we present the development of SiC MESFET-based digital circuitry, able to integrate gate driver for SiC power devices. Furthermore, a planar lateral power MESFET is developed with the aim of its co-integration on the same chip with the previously mentioned SiC digital ICs technology. And finally, experimental results on SiC Schottky-gated devices irradiated with protons and electrons are presented. This development is based on the Tungsten-Schottky interface technology used for the fabrication of stable SiC Schottky diodes for the European Space Agency Mission BepiColombo.

Radiation Assurance for the Space Environment

NASA Technical Reports Server (NTRS)

Barth, Janet L.; LaBel, Kenneth A.; Poivey, Christian

2004-01-01

The space radiation environment can lead to extremely harsh operating conditions for spacecraft electronic systems. A hardness assurance methodology must be followed to assure that the space radiation environment does not compromise the functionality and performance of space-based systems during the mission lifetime. The methodology includes a definition of the radiation environment, assessment of the radiation sensitivity of parts, worst-case analysis of the impact of radiation effects, and part acceptance decisions which are likely to include mitigation measures.

HEAT Sensor: Harsh Environment Adaptable Thermionic Sensor

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

Limb, Scott J.

2016-05-31

This document is the final report for the “HARSH ENVIRONMENT ADAPTABLE THERMIONIC SENSOR” project under NETL’s Crosscutting contract DE-FE0013062. This report addresses sensors that can be made with thermionic thin films along with the required high temperature hermetic packaging process. These sensors can be placed in harsh high temperature environments and potentially be wireless and self-powered.

NASA's Space Environments and Effects Program: Technology for the New Millennium

NASA Technical Reports Server (NTRS)

Hardage, Donna M.; Pearson, Steven D.

2000-01-01

Current trends in spacecraft development include the use of advanced technologies while maintaining the "faster, better, cheaper" philosophy. Spacecraft designers are continually designing with smaller and faster electronics as well as lighter and thinner materials providing better performance, lower weight, and ultimately lower costs. Given this technology trend, spacecraft will become increasingly susceptible to the harsh space environments, causing damaging or even disabling effects on space systems. NASA's Space Environments and Effects (SEE) Program defines the space environments and provides advanced technology development to support the design, development, and operation of spacecraft systems that will accommodate or mitigate effects due to the harsh space environments. This Program provides a comprehensive and focused approach to understanding the space environment, to define the best techniques for both flight and ground-based experimentation, to update the models which predict both the environments and the environmental effects on spacecraft, and finally to ensure that this multitudinous information is properly maintained and inserted into spacecraft design programs. A description of the SEE Program, its accomplishments, and future activities is provided.

A Radiation Hardened by Design CMOS ASIC for Thermopile Readouts

NASA Technical Reports Server (NTRS)

Quilligan, G.; Aslam, S.; DuMonthier, J.

2012-01-01

A radiation hardened by design (RHBD) mixed-signal application specific integrated circuit (ASIC) has been designed for a thermopile readout for operation in the harsh Jovian orbital environment. The multi-channel digitizer (MCD) ASIC includes 18 low noise amplifier channels which have tunable gain/filtering coefficients, a 16-bit sigma-delta analog-digital converter (SDADC) and an on-chip controller. The 18 channels, SDADC and controller were designed to operate with immunity to single event latchup (SEL) and to at least 10 Mrad total ionizing dose (TID). The ASIC also contains a radiation tolerant 16-bit 20 MHz Nyquist ADC for general purpose instrumentation digitizer needs. The ASIC is currently undergoing fabrication in a commercial 180 nm CMOS process. Although this ASIC was designed specifically for the harsh radiation environment of the NASA led JEO mission it is suitable for integration into instrumentation payloads 011 the ESA JUICE mission where the radiation hardness requirements are slightly less stringent.

Review of Research Status and Development Trends of Wireless Passive LC Resonant Sensors for Harsh Environments.

PubMed

Li, Chen; Tan, Qiulin; Jia, Pinggang; Zhang, Wendong; Liu, Jun; Xue, Chenyang; Xiong, Jijun

2015-06-04

Measurement technology for various key parameters in harsh environments (e.g., high-temperature and biomedical applications) continues to be limited. Wireless passive LC resonant sensors offer long service life and can be suitable for harsh environments because they can transmit signals without battery power or wired connections. Consequently, these devices have become the focus of many current research studies. This paper addresses recent research, key technologies, and practical applications relative to passive LC sensors used to monitor temperature, pressure, humidity, and harmful gases in harsh environments. The advantages and disadvantages of various sensor types are discussed, and prospects and challenges for future development of these sensors are presented.

Review of Research Status and Development Trends of Wireless Passive LC Resonant Sensors for Harsh Environments

PubMed Central

Li, Chen; Tan, Qiulin; Jia, Pinggang; Zhang, Wendong; Liu, Jun; Xue, Chenyang; Xiong, Jijun

2015-01-01

Measurement technology for various key parameters in harsh environments (e.g., high-temperature and biomedical applications) continues to be limited. Wireless passive LC resonant sensors offer long service life and can be suitable for harsh environments because they can transmit signals without battery power or wired connections. Consequently, these devices have become the focus of many current research studies. This paper addresses recent research, key technologies, and practical applications relative to passive LC sensors used to monitor temperature, pressure, humidity, and harmful gases in harsh environments. The advantages and disadvantages of various sensor types are discussed, and prospects and challenges for future development of these sensors are presented. PMID:26053753

Solar energy parking canopy demonstration project

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

Cylwik, Joe; David, Lawrence

2015-09-24

The goal of this pilot/demonstration program is to measure the viability of using solar photovoltaic (PV) technology at three locations in a mountain community environment given the harsh weather conditions. An additional goal is to reduce long-term operational costs, minimize green house gas emissions, lower the dependency on energy produced from fossil fuels, and improve the working environment and health of city employees and residents.

Thin Film Ceramic Strain Sensor Development for High Temperature Environments

NASA Technical Reports Server (NTRS)

Wrbanek, John D.; Fralick, Gustave C.; Gonzalez, Jose M.; Laster, Kimala L.

2008-01-01

The need for sensors to operate in harsh environments is illustrated by the need for measurements in the turbine engine hot section. The degradation and damage that develops over time in hot section components can lead to catastrophic failure. At present, the degradation processes that occur in the harsh hot section environment are poorly characterized, which hinders development of more durable components, and since it is so difficult to model turbine blade temperatures, strains, etc, actual measurements are needed. The need to consider ceramic sensing elements is brought about by the temperature limits of metal thin film sensors in harsh environments. The effort at the NASA Glenn Research Center (GRC) to develop high temperature thin film ceramic static strain gauges for application in turbine engines is described, first in the fan and compressor modules, and then in the hot section. The near-term goal of this research effort was to identify candidate thin film ceramic sensor materials and provide a list of possible thin film ceramic sensor materials and corresponding properties to test for viability. A thorough literature search was conducted for ceramics that have the potential for application as high temperature thin film strain gauges chemically and physically compatible with the NASA GRCs microfabrication procedures and substrate materials. Test results are given for tantalum, titanium and zirconium-based nitride and oxynitride ceramic films.

Designing for the Barely Imaginable

ERIC Educational Resources Information Center

Fisher, Diane

2007-01-01

National Aeronautics and Space Administration (NASA) has already sent many technological instruments into outer space. All these instruments were designed and built especially to operate in harsh and alien environments. How do NASA engineers know what kinds of planetary instruments to develop in the first place? Well, they ask. Once engineers…

Life testing of reflowed and reworked advanced CCGA surface mount packages in harsh thermal environments

NASA Astrophysics Data System (ADS)

Ramesham, Rajeshuni

2013-03-01

Life testing/qualification of reflowed (1st reflow) and reworked (1st reflow, 1st removal, and then 1st rework) advanced ceramic column grid array (CCGA) surface mount interconnect electronic packaging technologies for future flight projects has been studied to enhance the mission assurance of JPL-NASA projects. The reliability of reworked/reflowed surface mount technology (SMT) packages is very important for short-duration and long-duration deep space harsh extreme thermal environmental missions. The life testing of CCGA electronic packages under extreme thermal environments (for example: -185°C to +125°C) has been performed with reference to various JPL/NASA project requirements which encompass the temperature range studied. The test boards of reflowed and reworked CCGA packages (717 Xilinx package, 624, 1152, and 1272 column Actel Packages) were selected for the study to survive three times the total number of expected temperature cycles resulting from all environmental and operational exposures occurring over the life of the flight hardware including all relevant manufacturing, ground operations, and mission phases or cycles to failure to assess the life of the hardware. Qualification/life testing was performed by subjecting test boards to the environmental harsh temperature extremes and assessing any structural failures, mechanical failures or degradation in electrical performance solder-joint failures due to either overstress or thermal cycle fatigue. The large, high density, high input/output (I/O) electronic interconnect SMT packages such as CCGA have increased usage in avionics hardware of NASA projects during the last two decades. The test boards built with CCGA packages are expensive and often require a rework to replace a reflowed, reprogrammed, failed, redesigned, etc., CCGA packages. Theoretically speaking, a good rework process should have similar temperature-time profile as that used for the original manufacturing process of solder reflow. A multiple rework processes may be implemented with CCGA packaging technology to understand the effect of number of reworks on the reliability of this technology for harsh thermal environments. In general, reliability of the assembled electronic packages reduces as a function of number of reworks and the extent is not known yet. A CCGA rework process has been tried and implemented to design a daisy-chain test board consists of 624 and 717 packages. Reworked CCGA interconnect electronic packages of printed wiring polyimide boards have been assembled and inspected using non-destructive x-ray imaging and optical microscope techniques. The assembled boards after 1st rework and 1st reflow were subjected to extreme temperature thermal atmospheric cycling to assess their reliability for future deep space JPL/NASA for moderate to harsh thermal mission environments. The resistance of daisy-chained interconnect sections were monitored continuously during thermal cycling to determine intermittent failures. This paper provides the experimental reliability test results to failure of assemblies for the first time of reflowed and reworked CCGA packages under extreme harsh thermal environments.

A Life History Approach to Delineating How Harsh Environments and Hawk Temperament Traits Differentially Shape Children's Problem-Solving Skills

ERIC Educational Resources Information Center

Suor, Jennifer H.; Sturge-Apple, Melissa L.; Davies, Patrick T.; Cicchetti, Dante

2017-01-01

Harsh environments are known to predict deficits in children's cognitive abilities. Life history theory approaches challenge this interpretation, proposing stressed children's cognition becomes specialized to solve problems in fitness-enhancing ways. The goal of this study was to examine associations between early environmental harshness and…

Thermal Flow Sensors for Harsh Environments.

PubMed

Balakrishnan, Vivekananthan; Phan, Hoang-Phuong; Dinh, Toan; Dao, Dzung Viet; Nguyen, Nam-Trung

2017-09-08

Flow sensing in hostile environments is of increasing interest for applications in the automotive, aerospace, and chemical and resource industries. There are thermal and non-thermal approaches for high-temperature flow measurement. Compared to their non-thermal counterparts, thermal flow sensors have recently attracted a great deal of interest due to the ease of fabrication, lack of moving parts and higher sensitivity. In recent years, various thermal flow sensors have been developed to operate at temperatures above 500 °C. Microelectronic technologies such as silicon-on-insulator (SOI), and complementary metal-oxide semiconductor (CMOS) have been used to make thermal flow sensors. Thermal sensors with various heating and sensing materials such as metals, semiconductors, polymers and ceramics can be selected according to the targeted working temperature. The performance of these thermal flow sensors is evaluated based on parameters such as thermal response time, flow sensitivity. The data from thermal flow sensors reviewed in this paper indicate that the sensing principle is suitable for the operation under harsh environments. Finally, the paper discusses the packaging of the sensor, which is the most important aspect of any high-temperature sensing application. Other than the conventional wire-bonding, various novel packaging techniques have been developed for high-temperature application.

Thermal Flow Sensors for Harsh Environments

PubMed Central

Dinh, Toan; Dao, Dzung Viet

2017-01-01

Flow sensing in hostile environments is of increasing interest for applications in the automotive, aerospace, and chemical and resource industries. There are thermal and non-thermal approaches for high-temperature flow measurement. Compared to their non-thermal counterparts, thermal flow sensors have recently attracted a great deal of interest due to the ease of fabrication, lack of moving parts and higher sensitivity. In recent years, various thermal flow sensors have been developed to operate at temperatures above 500 °C. Microelectronic technologies such as silicon-on-insulator (SOI), and complementary metal-oxide semiconductor (CMOS) have been used to make thermal flow sensors. Thermal sensors with various heating and sensing materials such as metals, semiconductors, polymers and ceramics can be selected according to the targeted working temperature. The performance of these thermal flow sensors is evaluated based on parameters such as thermal response time, flow sensitivity. The data from thermal flow sensors reviewed in this paper indicate that the sensing principle is suitable for the operation under harsh environments. Finally, the paper discusses the packaging of the sensor, which is the most important aspect of any high-temperature sensing application. Other than the conventional wire-bonding, various novel packaging techniques have been developed for high-temperature application. PMID:28885595

Thermal history sensors for non-destructive temperature measurements in harsh environments

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

Pilgrim, C. C.; Heyes, A. L.; Feist, J. P.

2014-02-18

The operating temperature is a critical physical parameter in many engineering applications, however, can be very challenging to measure in certain environments, particularly when access is limited or on rotating components. A new quantitative non-destructive temperature measurement technique has been proposed which relies on thermally induced permanent changes in ceramic phosphors. This technique has several distinct advantages over current methods for many different applications. The robust ceramic material stores the temperature information allowing long term thermal exposures in harsh environment to be measured at a convenient time. Additionally, rare earth dopants make the ceramic phosphorescent so that the temperature informationmore » can be interpreted by automated interrogation of the phosphorescent light. This technique has been demonstrated by application of YAG doped with dysprosium and europium as coatings through the air-plasma spray process. Either material can be used to measure temperature over a wide range, namely between 300°C and 900°C. Furthermore, results show that the material records the peak exposure temperature and prolonged exposure at lower temperatures would have no effect on the temperature measurement. This indicates that these materials could be used to measure peak operating temperatures in long-term testing.« less

Geomagnetic referencing in the arctic environment

USGS Publications Warehouse

Podjono, Benny; Beck, Nathan; Buchanan, Andrew; Brink, Jason; Longo, Joseph; Finn, Carol A.; Worthington, E. William

2011-01-01

Geomagnetic referencing is becoming an increasingly attractive alternative to north-seeking gyroscopic surveys to achieve the precise wellbore positioning essential for success in today's complex drilling programs. However, the greater magnitude of variations in the geomagnetic environment at higher latitudes makes the application of geomagnetic referencing in those areas more challenging. Precise, real-time data on those variations from relatively nearby magnetic observatories can be crucial to achieving the required accuracy, but constructing and operating an observatory in these often harsh environments poses a number of significant challenges. Operational since March 2010, the Deadhorse Magnetic Observatory (DED), located in Deadhorse, Alaska, was created through collaboration between the United States Geological Survey (USGS) and a leading oilfield services supply company. DED was designed to produce real-time geomagnetic data at the required level of accuracy, and to do so reliably under the extreme temperatures and harsh weather conditions often experienced in the area. The observatory will serve a number of key scientific communities as well as the oilfield drilling industry, and has already played a vital role in the success of several commercial ventures in the area, providing essential, accurate data while offering significant cost and time savings, compared with traditional surveying techniques.

Geomagnetic referencing in the arctic environment

USGS Publications Warehouse

Poedjono, B.; Beck, N.; Buchanan, A. C.; Brink, J.; Longo, J.; Finn, C.A.; Worthington, E.W.

2011-01-01

Geomagnetic referencing is becoming an increasingly attractive alternative to north-seeking gyroscopic surveys to achieve the precise wellbore positioning essential for success in today's complex drilling programs. However, the greater magnitude of variations in the geomagnetic environment at higher latitudes makes the application of geomagnetic referencing in those areas more challenging. Precise, real-time data on those variations from relatively nearby magnetic observatories can be crucial to achieving the required accuracy, but constructing and operating an observatory in these often harsh environments poses a number of significant challenges. Operational since March 2010, the Deadhorse Magnetic Observatory (DED), located in Deadhorse, Alaska, was created through collaboration between the United States Geological Survey (USGS) and a leading oilfield services supply company. DED was designed to produce real-time geomagnetic data at the required level of accuracy, and to do so reliably under the extreme temperatures and harsh weather conditions often experienced in the area. The observatory will serve a number of key scientific communities as well as the oilfield drilling industry, and has already played a vital role in the success of several commercial ventures in the area, providing essential, accurate data while offering significant cost and time savings, compared with traditional surveying techniques. Copyright 2011, Society of Petroleum Engineers.

Passive Wireless Hermetic Environment Monitoring System for Spray Painting Workshop

PubMed Central

Wang, Lifeng; Ma, Jingjing; Huang, Yan; Tang, Dan; Huang, Qing-An

2016-01-01

Passive wireless sensors have the advantages of operating without a power supply and remote sensing capability. Hence, they are very suitable for some harsh environments, such as hermetic environments, rotating parts, or very high temperature environments. The spray painting workshop is such a harsh environment, containing a large amount of flammable paint mist and organic gas. Aiming at this special environment of spray painting workshop, a passive wireless hermetic environment monitoring system was designed, fabricated, and demonstrated. The proposed system is composed of a transponder and a reader, and the circuit design of each part is given in detail in this paper. The power and the data transmission between the transponder and the reader are realized by the inductive coupling mechanism. Utilizing the back scatter modulation and channel multiplexing, the frequency signals generated by three different environmental sensors—together with their interfaces in the transponder—are wirelessly read out by the reader. Because of the harsh environment of the spray painting room, the package of the monitoring system is quite important. Three different kinds of filter films for the system package were compared. The experimental results show that the composite filter film aluminum anodic oxide/polytetrafluoroethylene (AAO/PTFE) has the best performance. After fabrication, the measured temperature, humidity, and pressure sensitivities were measured and found to be 180 Hz/°C in the range of 0~60 °C, 100 Hz/%RH in the range of 15~95 %RH, and 42 Hz/hPa in the range of 600~1100 hPa, respectively. Additionally, the remote sensing distance of the monitoring system reaches 4 cm. Finally, the passive wireless hermetic environment monitoring system was installed on the glass wall of the spray painting workshop and was successfully demonstrated. PMID:27490546

Forgone but not forgotten: the effects of partial and full feedback in "harsh" and "kind" environments.

PubMed

Rakow, Tim; Newell, Ben R; Wright, Louise

2015-12-01

In a perfect world, the choice of any course of action would lead to a satisfactory outcome, and we would obtain feedback about both our chosen course and those we have chosen to forgo. In reality, however, we often face harsh environments in which we can only minimize losses, and we receive impoverished feedback. In these studies, we examined how decision makers dealt with these challenges in a simple task in which we manipulated three features of the decision: The outcomes from the available options were either mostly positive or mostly negative (kind or harsh environment); feedback was either full or partial (outcomes revealed for all options or only for the chosen option); and for the final 20 trials in a sequence, participants either chose on each trial or set an "advance-directive" policy. The propensity to choose the better option was explained by several factors: Full feedback was more beneficial in harsh than in kind environments; policy decisions encouraged better decisions and ameliorated the adverse impact of a harsh environment; and beliefs about the value of strategy diversification predicted switch rates and choice quality. The results suggest a subtle interplay between bottom-up and top-down processes: Although harsh environments encourage poor choices, and some decision makers choose less well than others, this need not imply that the decision maker has failed to identify the better option.

Real-time closed-loop simulation and upset evaluation of control systems in harsh electromagnetic environments

NASA Technical Reports Server (NTRS)

Belcastro, Celeste M.

1989-01-01

Digital control systems for applications such as aircraft avionics and multibody systems must maintain adequate control integrity in adverse as well as nominal operating conditions. For example, control systems for advanced aircraft, and especially those with relaxed static stability, will be critical to flight and will, therefore, have very high reliability specifications which must be met regardless of operating conditions. In addition, multibody systems such as robotic manipulators performing critical functions must have control systems capable of robust performance in any operating environment in order to complete the assigned task reliably. Severe operating conditions for electronic control systems can result from electromagnetic disturbances caused by lightning, high energy radio frequency (HERF) transmitters, and nuclear electromagnetic pulses (NEMP). For this reason, techniques must be developed to evaluate the integrity of the control system in adverse operating environments. The most difficult and illusive perturbations to computer-based control systems that can be caused by an electromagnetic environment (EME) are functional error modes that involve no component damage. These error modes are collectively known as upset, can occur simultaneously in all of the channels of a redundant control system, and are software dependent. Upset studies performed to date have not addressed the assessment of fault tolerant systems and do not involve the evaluation of a control system operating in a closed-loop with the plant. A methodology for performing a real-time simulation of the closed-loop dynamics of a fault tolerant control system with a simulated plant operating in an electromagnetically harsh environment is presented. In particular, considerations for performing upset tests on the controller are discussed. Some of these considerations are the generation and coupling of analog signals representative of electromagnetic disturbances to a control system under test, analog data acquisition, and digital data acquisition from fault tolerant systems. In addition, a case study of an upset test methodology for a fault tolerant electromagnetic aircraft engine control system is presented.

Implementation of a Readout Circuit on SOI Technology for the Signal Conditioning of a Neutron Detector in Harsh Environment

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

Ben Krit, S.; Coulie-Castellani, K.; Rahajandraibe, W.

2015-07-01

A transistor level implementation of the analog block of a readout system on SOI process is presented here. This system is dedicated to the signal conditioning of a neutron detector in harsh environment. The different parts of the readout circuits are defined. The harsh environment constraints (crossing particle effect, high temperatures) are also detailed and modeled in the circuit in order to test and evaluate the characteristics of the designed block when working under these conditions. (authors)

Development of a Temperature Sensor for Jet Engine and Space Missions Environments

NASA Technical Reports Server (NTRS)

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

2008-01-01

Electronic systems in aerospace and in space exploration missions are expected to encounter extreme temperatures and wide thermal swings. To address the needs for extreme temperature electronics, research efforts exist at the NASA Glenn Research Center (GRC) to develop and evaluate electronics for extreme temperature operations, and to establish their reliability under extreme temperature operation and thermal cycling; conditions that are typical of both the aerospace and space environments. These efforts are supported by the NASA Fundamental Aeronautics/Subsonic Fixed Wing Program and by the NASA Electronic Parts and Packaging (NEPP) Program. This work reports on the results obtained on the development of a temperature sensor geared for use in harsh environments.

The scabies problem on active service.

PubMed

Ross, David A

2014-06-01

The paper set out by identifying the significant advantage that disease gives to the enemy-plus ca change! Scabies was the commonest skin infection, and uncomplicated cases took 3-4 days to treat, but more complicated cases often resulted in hospitalisation for up to a month. Complicated cases were the norm through, because of the harsh environment that soldiers operated in.

Wearable oximetry for harsh environments

DTIC Science & Technology

2017-02-23

Firefighters, first responders, warfighters, and explorers must often operate in environmental extremes of temperature (hot or cold), humidity...PSMs) for thermal- work strain are maturing. These monitors typically measure heart rate (HR) from an electrocardiogram (ECG), skin temperature , and...add three primary benefits to PSMs: 1) monitoring altitude sickness and acclimatization via SpO2 (peripheral oxygen saturation) [2], 2) detecting

Rugged optical mirrors for the operation of Fourier-Transform Spectrometers in rough environments

NASA Astrophysics Data System (ADS)

Feist, Dietrich G.

2014-05-01

The Total Carbon Column Observing Network (TCCON) and the Network for the Detection of Atmospheric Composition Change (NDACC) operate a growing number of Fourier-Transform Spectrometers (FTS) that measure the total column of several atmospheric trace gases. For these measurements, the sun is used as a light source. This is typically achieved by a solar tracker that uses a pair of optical mirrors to guide the sunlight into the instrument. There is a growing demand to operate these instruments in remote locations that fill the gaps in the global observation network. Besides the logistical challenges of running a remote site, the environment at these locations can be very harsh compared to the sheltered environment of the instruments' home institutions. While the FTS itself is usually well protected inside a building or container, the solar tracker and especially its mirrors are exposed to the environment. There they may suffer from - temperature fluctuations - high humidity - sea salt corrosion at coastal sites - dirt and dust - air pollution from anthropogenic sources - deposition from plants or animals The Max Planck Institute for Biogeochemistry (MPI-BGC) operates a TCCON station on Ascension Island, about 200 m from the sea. Under the rough conditions at this site, typical optical mirrors that are made for laboratory conditions are destroyed by sea salt spray within a few weeks. Besides, typical gold-coated mirrors cannot be cleaned as their soft surface is easily scratched or damaged. To overcome these problems, the MPI-BGC has developed optical mirrors that - offer good reflectivity in the near and mid infrared - are highly resistant to salt and chlorine - have a hard surface so that they can be cleaned often and easily - are not affected by organic solvents - last for months in very harsh environments - can be reused after polishing These mirrors could be applied to most TCCON and NDACC sites. This way, the network could be expanded to regions where operation would have been too challenging so far.

Nano-Fabrication Methods for Micro-Miniature Optical Thermometers Suited to High Temperatures and Harsh Environments

NASA Astrophysics Data System (ADS)

DePew, K. A.; Ma, C.; Schiffbauer, J. D.; Wang, J.; Dong, B.; Lally, E.; Wang, A.

2012-12-01

The Center for Photonics Technology (CPT) at Virginia Tech is engaged in cutting edge research of fiber optic sensing technologies. One current research area is the design of fiber optic temperature sensors for harsh environments. Fiber optic temperature sensing offers significant advantages over electronic sensing in terms of size and insensitivity to harsh environmental conditions and electromagnetic interference. In the field, fiber optic thermometers have been used in recent snow cover studies as well as fluvial temperature profiling projects. The extended capabilities of CPT optical sensors open further possibilities for application in additional geologic realms requiring high temperature sensing in corrosive environments. Significant strides have been made in developing single-crystal sapphire based fiber optic sensing elements for high temperature environments which are otherwise difficult to instrument. Utilization of strain insensitive designs and optical sapphire materials allow for thermometers capable of operation above 1500°C with reduced sensitivity to chemical corrosion and mechanical interference. Current efforts in fabrication techniques are reducing the footprint of temperature sensors below the millimeter scale while maintaining high resolution and operating range. The FEI Helios 600 NanoLab workstation at the Virginia Tech Institute for Critical Technologies and Applied Science has been employed, providing the capabilities necessary to reduce the footprint of sensing elements to the dimensions of standard optical communication fiber using a Ga+ focused ion beam (FIB). The capability of semi-distributed multi-point sensing can also be accomplished at this scale using similar FIB milling techniques. The fiber optic thermometer designs resulting from these methods are compact, lightweight, and able to provide remote sensing without need for electrical power at the measurement point. These traits make them an ideal sensing platform for laboratory applications with minimal instrumentation egress as well as field deployment in areas where traditional electronic technologies cannot survive.

A life history approach to delineating how harsh environments and hawk temperament traits differentially shape children's problem-solving skills.

PubMed

Suor, Jennifer H; Sturge-Apple, Melissa L; Davies, Patrick T; Cicchetti, Dante

2017-08-01

Harsh environments are known to predict deficits in children's cognitive abilities. Life history theory approaches challenge this interpretation, proposing stressed children's cognition becomes specialized to solve problems in fitness-enhancing ways. The goal of this study was to examine associations between early environmental harshness and children's problem-solving outcomes across tasks varying in ecological relevance. In addition, we utilize an evolutionary model of temperament toward further specifying whether hawk temperament traits moderate these associations. Two hundred and one mother-child dyads participated in a prospective multimethod study when children were 2 and 4 years old. At age 2, environmental harshness was assessed via maternal report of earned income and observations of maternal disengagement during a parent-child interaction task. Children's hawk temperament traits were assessed from a series of unfamiliar episodes. At age 4, children's reward-oriented and visual problem-solving were measured. Path analyses revealed early environmental harshness and children's hawk temperament traits predicted worse visual problem-solving. Results showed a significant two-way interaction between children's hawk temperament traits and environmental harshness on reward-oriented problem-solving. Simple slope analyses revealed the effect of environmental harshness on reward-oriented problem-solving was specific to children with higher levels of hawk traits. Results suggest early experiences of environmental harshness and child hawk temperament traits shape children's trajectories of problem-solving in an environment-fitting manner. © 2017 Association for Child and Adolescent Mental Health.

Cooperation in Harsh Environments and the Emergence of Spatial Patterns.

PubMed

Smaldino, Paul E

2013-11-01

This paper concerns the confluence of two important areas of research in mathematical biology: spatial pattern formation and cooperative dilemmas. Mechanisms through which social organisms form spatial patterns are not fully understood. Prior work connecting cooperation and pattern formation has often included unrealistic assumptions that shed doubt on the applicability of those models toward understanding real biological patterns. I investigated a more biologically realistic model of cooperation among social actors. The environment is harsh, so that interactions with cooperators are strictly needed to survive. Harshness is implemented via a constant energy deduction. I show that this model can generate spatial patterns similar to those seen in many naturally-occuring systems. Moreover, for each payoff matrix there is an associated critical value of the energy deduction that separates two distinct dynamical processes. In low-harshness environments, the growth of cooperator clusters is impeded by defectors, but these clusters gradually expand to form dense dendritic patterns. In very harsh environments, cooperators expand rapidly but defectors can subsequently make inroads to form reticulated patterns. The resulting web-like patterns are reminiscent of transportation networks observed in slime mold colonies and other biological systems.

Harsh Environments, Life History Strategies, and Adjustment: A Longitudinal Study of Oregon Youth

PubMed Central

Hampson, Sarah E.; Andrews, Judy A.; Barckley, Maureen; Gerrard, Meg; Gibbons, Frederick X.

2015-01-01

We modeled the effects of harsh environments in childhood on adjustment in early emerging adulthood, through parenting style and the development of fast Life History Strategies (LHS; risky beliefs and behaviors) in adolescence. Participants were from the Oregon Youth Substance Use Project (N = 988; 85.7% White). Five cohorts of children in Grades 1–5 at recruitment were assessed through one-year post high school. Greater environmental harshness (neighborhood quality and family poverty) in Grades 1–6 predicted less parental investment at Grade 8. This parenting style was related to the development of fast LHS (favorable beliefs about substance users and willingness to use substances at Grade 9, and engagement in substance use and risky sexual behavior assessed across Grades 10–12). The indirect path from harsh environment through parenting and LHS to (less) psychological adjustment (indicated by lower life satisfaction, self-rated health, trait sociability, and higher depression) was significant (indirect effect −.024, p = .011, 95% CI = −.043, −.006.). This chain of development was comparable to that found by Gibbons et al. (2012) for an African-American sample that, unlike the present study, included perceived racial discrimination in the assessment of harsh environment. PMID:26451065

Wireless Sensor Networks for Environmental Monitoring

NASA Astrophysics Data System (ADS)

Liang, X.; Liang, Y.; Navarro, M.; Zhong, X.; Villalba, G.; Li, Y.; Davis, T.; Erratt, N.

2015-12-01

Wireless sensor networks (WSNs) have gained an increasing interest in a broad range of new scientific research and applications. WSN technologies can provide high resolution for spatial and temporal data which has not been possible before, opening up new opportunities. On the other hand, WSNs, particularly outdoor WSNs in harsh environments, present great challenges for scientists and engineers in terms of the network design, deployment, operation, management, and maintenance. Since 2010, we have been working on the deployment of an outdoor multi-hop WSN testbed for hydrological/environmental monitoring in a forested hill-sloped region at the Audubon Society of Western Pennsylvania (ASWP), Pennsylvania, USA. The ASWP WSN testbed has continuously evolved and had more than 80 nodes by now. To our knowledge, the ASWP WSN testbed represents one of the first known long-term multi-hop WSN deployments in an outdoor environment. As simulation and laboratory methods are unable to capture the complexity of outdoor environments (e.g., forests, oceans, mountains, or glaciers), which significantly affect WSN operations and maintenance, experimental deployments are essential to investigate and understand WSN behaviors and performances as well as its maintenance characteristics under these harsh conditions. In this talk, based on our empirical studies with the ASWP WSN testbed, we will present our discoveries and investigations on several important aspects including WSN energy profile, node reprogramming, network management system, and testbed maintenance. We will then provide our insight into these critical aspects of outdoor WSN deployments and operations.

Assessment of vehicle performance in harsh environments using LSU driving simulator and numerical simulations.

DOT National Transportation Integrated Search

2015-12-01

With the economic booming development of coastal areas, the importance of the traffic planning becomes : obvious not only in a hurricane evacuation but also in the daily transportation. Vehicle performance on the : freeway during harsh environments i...

Microfibrous metallic cloth for acoustic isolation of a MEMS gyroscope

NASA Astrophysics Data System (ADS)

Dean, Robert; Burch, Nesha; Black, Meagan; Beal, Aubrey; Flowers, George

2011-04-01

The response of a MEMS device that is exposed to a harsh environment may range from an increased noise floor to a completely erroneous output to temporary or even permanent device failure. One such harsh environment is high power acoustic energy possessing high frequency components. This type of environment sometimes occurs in small aerospace vehicles. In this type of operating environment, high frequency acoustic energy can be transferred to a MEMS gyroscope die through the device packaging. If the acoustic noise possesses a sufficiently strong component at the resonant frequency of the gyroscope, it will overexcite the motion of the proof mass, resulting in the deleterious effect of corrupted angular rate measurement. Therefore if the device or system packaging can be improved to sufficiently isolate the gyroscope die from environmental acoustic energy, the sensor may find new applications in this type of harsh environment. This research effort explored the use of microfibrous metallic cloth for isolating the gyroscope die from environmental acoustic excitation. Microfibrous cloth is a composite of fused, intermingled metal fibers and has a variety of typical uses involving chemical processing applications and filtering. Specifically, this research consisted of experimental evaluations of multiple layers of packed microfibrous cloth composed of sintered nickel material. The packed cloth was used to provide acoustic isolation for a test MEMS gyroscope, the Analog Devices ADXRS300. The results of this investigation revealed that the intermingling of the various fibers of the metallic cloth provided a significant contact area between the fiber strands and voids, which enhanced the acoustic damping of the material. As a result, the nickel cloth was discovered to be an effective acoustic isolation material for this particular MEMS gyroscope.

Fundamental Dimensions of Environmental Risk : The Impact of Harsh versus Unpredictable Environments on the Evolution and Development of Life History Strategies.

PubMed

Ellis, Bruce J; Figueredo, Aurelio José; Brumbach, Barbara H; Schlomer, Gabriel L

2009-06-01

The current paper synthesizes theory and data from the field of life history (LH) evolution to advance a new developmental theory of variation in human LH strategies. The theory posits that clusters of correlated LH traits (e.g., timing of puberty, age at sexual debut and first birth, parental investment strategies) lie on a slow-to-fast continuum; that harshness (externally caused levels of morbidity-mortality) and unpredictability (spatial-temporal variation in harshness) are the most fundamental environmental influences on the evolution and development of LH strategies; and that these influences depend on population densities and related levels of intraspecific competition and resource scarcity, on age schedules of mortality, on the sensitivity of morbidity-mortality to the organism's resource-allocation decisions, and on the extent to which environmental fluctuations affect individuals versus populations over short versus long timescales. These interrelated factors operate at evolutionary and developmental levels and should be distinguished because they exert distinctive effects on LH traits and are hierarchically operative in terms of primacy of influence. Although converging lines of evidence support core assumptions of the theory, many questions remain unanswered. This review demonstrates the value of applying a multilevel evolutionary-developmental approach to the analysis of a central feature of human phenotypic variation: LH strategy.

The effect of environmental harshness on neurogenesis: a large-scale comparison.

PubMed

Chancellor, Leia V; Roth, Timothy C; LaDage, Lara D; Pravosudov, Vladimir V

2011-03-01

Harsh environmental conditions may produce strong selection pressure on traits, such as memory, that may enhance fitness. Enhanced memory may be crucial for survival in animals that use memory to find food and, thus, particularly important in environments where food sources may be unpredictable. For example, animals that cache and later retrieve their food may exhibit enhanced spatial memory in harsh environments compared with those in mild environments. One way that selection may enhance memory is via the hippocampus, a brain region involved in spatial memory. In a previous study, we established a positive relationship between environmental severity and hippocampal morphology in food-caching black-capped chickadees (Poecile atricapillus). Here, we expanded upon this previous work to investigate the relationship between environmental harshness and neurogenesis, a process that may support hippocampal cytoarchitecture. We report a significant and positive relationship between the degree of environmental harshness across several populations over a large geographic area and (1) the total number of immature hippocampal neurons, (2) the number of immature neurons relative to the hippocampal volume, and (3) the number of immature neurons relative to the total number of hippocampal neurons. Our results suggest that hippocampal neurogenesis may play an important role in environments where increased reliance on memory for cache recovery is critical. Copyright © 2010 Wiley Periodicals, Inc.

Field deployable processing methods for stay-in-place ultrasonic transducers

NASA Astrophysics Data System (ADS)

Malarich, Nathan; Lissenden, Cliff J.; Tittmann, Bernhard R.

2018-04-01

Condition monitoring provides key data for managing the operation and maintenance of mechanical equipment in the power generation, chemical processing, and manufacturing industries. Ultrasonic transducers provide active monitoring capabilities by wall thickness measurements, elastic property determination, crack detection, and other means. In many cases the components operate in harsh environments that may include high temperature, radiation, and hazardous chemicals. Thus, it is desirable to have permanently affixed ultrasonic transducers for condition monitoring in harsh environments. Spray-on transducers provide direct coupling between the active element and the substrate, and can be applied to curved surfaces. We describe a deposition methodology for ultrasonic transducers that can be applied in the field. First, piezoceramic powders mixed into a sol-gel are air-spray deposited onto the substrate. Powder constituents are selected based on the service environment in which the condition monitoring will be performed. Then the deposited coating is pyrolyzed and partially densified using an induction heating system with a custom work coil designed to match the substrate geometry. The next step, applying the electrodes, is more challenging than might be expected because of the porosity of the piezoelectric coating and the potential reactivity of elements in the adjacent layers. After connecting lead wires to the electrodes the transducer is poled and a protective coating can be applied prior to use. Processing of a PZT-bismuth titanate transducer on a large steel substrate is described along with alternate methods.

Vibration-tolerant narrow-linewidth semiconductor disk laser using novel frequency-stabilisation schemes

NASA Astrophysics Data System (ADS)

Hunter, Craig R.; Jones, Brynmor E.; Schlosser, Peter; Sørensen, Simon Toft; Strain, Michael J.; McKnight, Loyd J.

2018-02-01

This paper will present developments in narrow-linewidth semiconductor-disk-laser systems using novel frequencystabilisation schemes for reduced sensitivity to mechanical vibrations, a critical requirement for mobile applications. Narrow-linewidth single-frequency lasers are required for a range of applications including metrology and highresolution spectroscopy. Stabilisation of the laser was achieved using a monolithic fibre-optic ring resonator with free spectral range of 181 MHz and finesse of 52 to act as passive reference cavity for the laser. Such a cavity can operate over a broad wavelength range and is immune to a wide band of vibrational frequency noise due to its monolithic implementation. The frequency noise of the locked system has been measured and compared to typical Fabry-Perotlocked lasers using vibration equipment to simulate harsh environments, and analysed here. Locked linewidths of < 40 kHz have been achieved. These developments offer a portable, narrow-linewidth laser system for harsh environments that can be flexibly designed for a range of applications.

PDC cutters improve drilling in harsh environments

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

Mensa-Wilmot, G.

2000-02-01

Improvements in polycrystalline diamond compact (PDC) cutter technology have contributed immensely to the industry's acceptance of PDC bits as effective drilling tools. These cutters are being engineered to address the needs and requirements of different drilling programs. Extensive research and developments efforts have been dedicated to the analysis of the diamond table/tungsten carbide interface. The paper describes PDC cutter development, operational challenges, offset performance, and field experiences.

The design of the multipurpose Lusi drone. When technology can access harsh environments.

NASA Astrophysics Data System (ADS)

Romeo, Giovanni; Di Stefano, Giuseppe; Mazzini, Adriano; Iarocci, Alessandro

2016-04-01

Extreme and inaccessible environments are a new frontier that unmanned and remotely operated vehicles can today safely access and monitor. The Lusi mud eruption (NE Java Island, Indonesia) represents one of these harsh environments that are totally unreachable with traditional techniques. Here boiling mud is constantly spewed tens of meters in height and tall gas clouds surround the 100 meters wide active crater. The crater is surrounded by a 600 meters circular zone of hot mud that prevents any approach to investigate and sample the eruption site. In the framework of the Lusi Lab project (ERC grant n° 308126) we assembled and designed a multipurpose drone to survey the eruption site. The Lusi drone is equipped with numerous airborne devices suitable for use on board of other multicopters. During the missions three cameras can complete 1) video survey, 2) high resolution photogrammetry of desired and preselected polygons, and 3) thermal photogrammetry surveys with infra-red camera to locate hot fluids seepage areas or faulted zones. Crater sampling and monitoring operations can be pre-planned with a flight software, and the pilot is required only for take-off and landing. An automatic winch allows the deployment of gas, mud and water samplers and contact thermometers to be operated with no risk for the aircraft. During the winch operations (that can be performed automatically) the aircraft hovers at a safety height until the tasks are completed while being controlled by the winch embedded processor. The drone is also equipped with a GPS connected CO2 and CH4 sensors. Gridded surveys using these devices allowed obtaining 2D maps of the concentration and distribution of various gasses over the area covered by the flight path.

Self-Recovery Experiments in Extreme Environments Using a Field Programmable Transistor Array

NASA Technical Reports Server (NTRS)

Stoica, Adrian; Keymeulen, Didier; Arslan, Tughrul; Duong, Vu; Zebulum, Ricardo; Ferguson, Ian; Guo, Xin

2004-01-01

Temperature and radiation tolerant electronics, as well as long life survivability are key capabilities required for future NASA missions. Current approaches to electronics for extreme environments focus on component level robustness and hardening. However, current technology can only ensure very limited lifetime in extreme environments. This paper describes novel experiments that allow adaptive in-situ circuit redesign/reconfiguration during operation in extreme temperature and radiation environments. This technology would complement material/device advancements and increase the mission capability to survive harsh environments. The approach is demonstrated on a mixed-signal programmable chip (FPTA-2), which recovers functionality for temperatures until 28 C and with total radiation dose up to 250kRad.

Operation of commercially-based microcomputer technology in a space radiation environment

NASA Astrophysics Data System (ADS)

Yelverton, J. N.

This paper focuses on detection and recovery techniques that should enable the reliable operation of commercially-based microprocessor technology in the harsh radiation environment of space and at high altitudes. This approach is especially significant in light of the current shift in emphasis (due to cost) from space hardened Class-S parts qualification to a more direct use of commercial parts. The method should offset some of the concern that the newer high density state-of-the-art RISC and CISC microprocessors can be used in future space applications. Also, commercial aviation, should benefit, since radiation induced transients are a new issue arising from the increased quantities of microcomputers used in aircraft avionics.

Harsh childhood environmental characteristics predict exploitation and retaliation in humans

PubMed Central

McCullough, Michael E.; Pedersen, Eric J.; Schroder, Jaclyn M.; Tabak, Benjamin A.; Carver, Charles S.

2013-01-01

Across and within societies, people vary in their propensities towards exploitative and retaliatory defection in potentially cooperative interaction. We hypothesized that this variation reflects adaptive responses to variation in cues during childhood that life will be harsh, unstable and short—cues that probabilistically indicate that it is in one's fitness interests to exploit co-operators and to retaliate quickly against defectors. Here, we show that childhood exposure to family neglect, conflict and violence, and to neighbourhood crime, were positively associated for men (but not women) with exploitation of an interaction partner and retaliatory defection after that partner began to defect. The associations between childhood environment and both forms of defection for men appeared to be mediated by participants' endorsement of a ‘code of honour’. These results suggest that individual differences in mutual benefit cooperation are not merely due to genetic noise, random developmental variation or the operation of domain-general cultural learning mechanisms, but rather, might reflect the adaptive calibration of social strategies to local social–ecological conditions. PMID:23118435

Fabrication of Microhotplates Based on Laser Micromachining of Zirconium Oxide

NASA Astrophysics Data System (ADS)

Oblov, Konstantin; Ivanova, Anastasia; Soloviev, Sergey; Samotaev, Nikolay; Lipilin, Alexandr; Vasiliev, Alexey; Sokolov, Andrey

We present a novel approach to the fabrication of MEMS devices, which can be used for gas sensors operating in harsh environment in wireless and autonomous information systems. MEMS platforms based on ZrO2/Y2O3 (YSZ) are applied in these devices. The methods of ceramic MEMS devices fabrication with laser micromachining are considered. It is shown that the application of YSZ membranes permits a decrease in MEMS power consumption at 4500C down to ∼75 mW at continuous heating and down to ∼ 1 mW at pulse heating mode. The application of the platforms is not restricted by gas sensors: they can be used for fast thermometers, bolometric matrices, flowmeteres and other MEMS devices working under harsh environmental conditions.

Austere, remote, and disaster medicine missions: an operational mnemonic can help organize a deployment.

PubMed

Macias, Darryl J; Williams, Jason

2013-01-01

Medical care in resource-limited environments (austere settings) can occur in the context of a disaster, wilderness, or a tactical field operation. Regardless of the type of environment, there are common organizational themes in most successful humanitarian missions that occur in harsh natural or manmade environmental conditions. These principles prioritize the initiation and execution of any given deployment in austere or remote settings, diverging from priorities that would occur in a situation in which change to the existing medical structure is intact and operating well. Attention to these priorities not only helps providers to deliver medical care to people in need during a period of resource limitations but it also can keep providers, teams, the public, and patients safe during and after a deployment.

Application of tunable diode laser absorption spectroscopy in the detection of oxygen

NASA Astrophysics Data System (ADS)

Zhou, Xin; Jin, Xing

2015-10-01

Most aircrafts is driven by chemic energy which is released in the combustion process. For improving the capability of engine and controlling the running on-time, the processes of fuel physics and chemistry need to be analysis by kinds of high quality sensor. In the research of designing and improving the processes of fuel physics and chemistry, the concentration, temperature and velocity of kinds of gas in the combustor need to be detected and measured. In addition, these engines and research equipments are always in the harsh environment of high temperature, high pressure and high speed. The harsh environment needs the sensor to be high reliability, well repetition, no cross- sensitivity between gases, and the traditional measurement system can't satisfy the metrical requirement well. Tunable diode laser absorption spectroscopy (TDLAS) analytic measurement technology can well satisfy the measurement in the harsh environment, which can support the whole measurement plan and high quality measurement system. Because the TDLAS sensor has the excellence of small bulk, light weight, high reliability and well specifically measurement, the TDLAS measurement technology has wide prospects. Different from most measurements, only a beam of laser can be pass through the measured environment by TDLAS, and the measurement equipment needn't be set in the harsh environment. So, the TDLAS equipment can't be interrupted by the measured equipment. The ability of subsistence in the harsh environment is very valuable, especially in the measurement on the subject of aerospace with environment of high speed, combustion and plasma. This paper focuses on the collecting the articles on the subject of oxygen detection of TDLAS. By analyzing the research and results of the articles, we conclude the central issues, difficulties and results. And we can get some instructive conclusions.

Sensors Increase Productivity in Harsh Environments

NASA Technical Reports Server (NTRS)

2008-01-01

California's San Juan Capistrano-based Endevco Corporation licensed three patents covering high-temperature, harsh-environment silicon carbide (Si-C) pressure sensors from Glenn Research Center. The company is exploring their use in government markets, as well as in commercial markets, including commercial jet testing, deep well drilling applications where pressure and temperature increase with drilling depth, and in automobile combustion chambers.

A Reusable and Adaptable Software Architecture for Embedded Space Flight System: The Core Flight Software System (CFS)

NASA Technical Reports Server (NTRS)

Wilmot, Jonathan

2005-01-01

The contents include the following: High availability. Hardware is in harsh environment. Flight processor (constraints) very widely due to power and weight constraints. Software must be remotely modifiable and still operate while changes are being made. Many custom one of kind interfaces for one of a kind missions. Sustaining engineering. Price of failure is high, tens to hundreds of millions of dollars.

Emerging GaN-based HEMTs for mechanical sensing within harsh environments

NASA Astrophysics Data System (ADS)

Köck, Helmut; Chapin, Caitlin A.; Ostermaier, Clemens; Häberlen, Oliver; Senesky, Debbie G.

2014-06-01

Gallium nitride based high-electron-mobility transistors (HEMTs) have been investigated extensively as an alternative to Si-based power transistors by academia and industry over the last decade. It is well known that GaN-based HEMTs outperform Si-based technologies in terms of power density, area specific on-state resistance and switching speed. Recently, wide band-gap material systems have stirred interest regarding their use in various sensing fields ranging from chemical, mechanical, biological to optical applications due to their superior material properties. For harsh environments, wide bandgap sensor systems are deemed to be superior when compared to conventional Si-based systems. A new monolithic sensor platform based on the GaN HEMT electronic structure will enable engineers to design highly efficient propulsion systems widely applicable to the automotive, aeronautics and astronautics industrial sectors. In this paper, the advancements of GaN-based HEMTs for mechanical sensing applications are discussed. Of particular interest are multilayered heterogeneous structures where spontaneous and piezoelectric polarization between the interface results in the formation of a 2-dimensional electron gas (2DEG). Experimental results presented focus on the signal transduction under strained operating conditions in harsh environments. It is shown that a conventional AlGaN/GaN HEMT has a strong dependence of drain current under strained conditions, thus representing a promising future sensor platform. Ultimately, this work explores the sensor performance of conventional GaN HEMTs and leverages existing technological advances available in power electronics device research. The results presented have the potential to boost GaN-based sensor development through the integration of HEMT device and sensor design research.

TROPIX: A solar electric propulsion flight experiment

NASA Technical Reports Server (NTRS)

Hickman, J. Mark; Hillard, G. Barry; Oleson, Steven R.

1993-01-01

The Transfer Orbit Plasma Interaction Experiment (TROPIX) is a proposed scientific experiment and flight demonstration of a solar electric propulsion vehicle. Its mission goals are to significantly increase our knowledge of Earth's magnetosphere and its associated plasma environment and to demonstrate an operational solar electric upper stage (SEUS) for small launch vehicles. The scientific investigations and flight demonstration technology experiments are uniquely interrelated because of the spacecraft's interaction with the surrounding environment. The data obtained will complement previous studies of the Earth's magnetosphere and space plasma environment by supplying the knowledge necessary to attain the strategic objectives of the NASA Office of Space Science. This first operational use of a primary ion propulsion vehicle, designed to withstand the harsh environments from low Earth orbit to geosynchronous Earth orbit, may lead to the development of a new class of electric propulsion upper stages or space-based transfer vehicles and may improve future spacecraft design and safety.

Optical silicones for use in harsh operating environments

NASA Astrophysics Data System (ADS)

Riegler, Bill; Bruner, Stephen J.; Elgin, Randall

2004-12-01

The optics industry widely uses silcones for various fiber optic cable potting applications and light emitting diode protection. Optics manufacturers know traditional silicone elastomers, gels, thixotropic gels, and fluids not only perform extremely well in high temperature applications, but also offer refractive index matching so that silicones can transmit light with admirable efficiency. However, because environmental conditions may affect a material's performance over time, one must also consider the conditions the device operates in to ensure long-term reliability. External environments may include exposure to a combination of UV light and temperature, while other environments may expose devices to hydrocarbon based fuels. This paper will delve into the chemistry of silicones and functional groups that lend themselves to properties such as temperature, fuel, and radiation resistance to show shy silicone is the material of choice for optic applications under normally harmful forms of exposure. Data will be presented to examine silicone's performance in these environment.

Electromagnetic Acoustic Transducers for Robotic Nondestructive Inspection in Harsh Environments.

PubMed

Choi, Sungho; Cho, Hwanjeong; Lindsey, Matthew S; Lissenden, Cliff J

2018-01-11

Elevated temperature, gamma radiation, and geometric constraints inside dry storage casks for spent nuclear fuel represent a harsh environment for nondestructive inspection of the cask and require that the inspection be conducted with a robotic system. Electromagnetic acoustic transducers (EMATs) using non-contact ultrasonic transduction based on the Lorentz force to excite/receive ultrasonic waves are suited for use in the robotic inspection. Periodic permanent magnet EMATs that actuate/receive shear horizontal guided waves are developed for application to robotic nondestructive inspection of stress corrosion cracks in the heat affected zone of welds in stainless steel dry storage canisters. The EMAT's components are carefully selected in consideration of the inspection environment, and tested under elevated temperature and gamma radiation doses up to 177 °C and 5920 krad, respectively, to evaluate the performance of the EMATs under realistic environmental conditions. The effect of gamma radiation is minimal, but the EMAT's performance is affected by temperatures above 121 °C due to the low Curie temperature of the magnets. Different magnets are needed to operate at 177 °C. The EMAT's capability to detect notches is also evaluated from B-scan measurements on 304 stainless steel welded plate containing surface-breaking notches.

Space Qualification Issues in Acousto-optic and Electro-optic Devices

NASA Technical Reports Server (NTRS)

Prasad, Narasimha S.; Taylor, Edward W.; Trivedi, Sudhir; Kutcher, Sue; Soos, Jolanta

2007-01-01

Satellite and space-based applications of photonic devices and systems require operational reliability in the harsh environment of space for extended periods of time. This in turn requires every component of the systems and their packaging to meet space qualifications. Acousto- and electro-optical devices form the major components of many current space based optical systems, which is the focus of this paper. The major space qualification issues are related to: mechanical stability, thermal effects and operation of the devices in the naturally occurring space radiation environment. This paper will discuss acousto- and electro-optic materials and devices with respect to their stability against mechanical vibrations, thermal cycling in operating and non-operating conditions and device responses to space ionizing and displacement radiation effects. Selection of suitable materials and packaging to meet space qualification criteria will also be discussed. Finally, a general roadmap for production and testing of acousto- and electro-optic devices will be discussed.

High Temperature Electronics for Intelligent Harsh Environment Sensors

NASA Technical Reports Server (NTRS)

Evans, Laura J.

2008-01-01

The development of intelligent instrumentation systems is of high interest in both public and private sectors. In order to obtain this ideal in extreme environments (i.e., high temperature, extreme vibration, harsh chemical media, and high radiation), both sensors and electronics must be developed concurrently in order that the entire system will survive for extended periods of time. The semiconductor silicon carbide (SiC) has been studied for electronic and sensing applications in extreme environment that is beyond the capability of conventional semiconductors such as silicon. The advantages of SiC over conventional materials include its near inert chemistry, superior thermomechanical properties in harsh environments, and electronic properties that include high breakdown voltage and wide bandgap. An overview of SiC sensors and electronics work ongoing at NASA Glenn Research Center (NASA GRC) will be presented. The main focus will be two technologies currently being investigated: 1) harsh environment SiC pressure transducers and 2) high temperature SiC electronics. Work highlighted will include the design, fabrication, and application of SiC sensors and electronics, with recent advancements in state-of-the-art discussed as well. These combined technologies are studied for the goal of developing advanced capabilities for measurement and control of aeropropulsion systems, as well as enhancing tools for exploration systems.

Beyond main effects of gene-sets: harsh parenting moderates the association between a dopamine gene-set and child externalizing behavior.

PubMed

Windhorst, Dafna A; Mileva-Seitz, Viara R; Rippe, Ralph C A; Tiemeier, Henning; Jaddoe, Vincent W V; Verhulst, Frank C; van IJzendoorn, Marinus H; Bakermans-Kranenburg, Marian J

2016-08-01

In a longitudinal cohort study, we investigated the interplay of harsh parenting and genetic variation across a set of functionally related dopamine genes, in association with children's externalizing behavior. This is one of the first studies to employ gene-based and gene-set approaches in tests of Gene by Environment (G × E) effects on complex behavior. This approach can offer an important alternative or complement to candidate gene and genome-wide environmental interaction (GWEI) studies in the search for genetic variation underlying individual differences in behavior. Genetic variants in 12 autosomal dopaminergic genes were available in an ethnically homogenous part of a population-based cohort. Harsh parenting was assessed with maternal (n = 1881) and paternal (n = 1710) reports at age 3. Externalizing behavior was assessed with the Child Behavior Checklist (CBCL) at age 5 (71 ± 3.7 months). We conducted gene-set analyses of the association between variation in dopaminergic genes and externalizing behavior, stratified for harsh parenting. The association was statistically significant or approached significance for children without harsh parenting experiences, but was absent in the group with harsh parenting. Similarly, significant associations between single genes and externalizing behavior were only found in the group without harsh parenting. Effect sizes in the groups with and without harsh parenting did not differ significantly. Gene-environment interaction tests were conducted for individual genetic variants, resulting in two significant interaction effects (rs1497023 and rs4922132) after correction for multiple testing. Our findings are suggestive of G × E interplay, with associations between dopamine genes and externalizing behavior present in children without harsh parenting, but not in children with harsh parenting experiences. Harsh parenting may overrule the role of genetic factors in externalizing behavior. Gene-based and gene-set analyses offer promising new alternatives to analyses focusing on single candidate polymorphisms when examining the interplay between genetic and environmental factors.

Materials challenges for nuclear systems

DOE PAGES

Allen, Todd; Busby, Jeremy; Meyer, Mitch; ...

2010-11-26

The safe and economical operation of any nuclear power system relies to a great extent, on the success of the fuel and the materials of construction. During the lifetime of a nuclear power system which currently can be as long as 60 years, the materials are subject to high temperature, a corrosive environment, and damage from high-energy particles released during fission. The fuel which provides the power for the reactor has a much shorter life but is subject to the same types of harsh environments. This article reviews the environments in which fuels and materials from current and proposed nuclearmore » systems operate and then describes how the creation of the Advanced Test Reactor National Scientific User Facility is allowing researchers from across the U.S. to test their ideas for improved fuels and materials.« less

Progress of a Cross-Correlation Based Optical Strain Measurement Technique for Detecting Radial Growth on a Rotating Disk

NASA Technical Reports Server (NTRS)

Clem, Michelle M.; Abdul-Aziz, Ali; Woike, Mark R.; Fralick, Gustave C.

2015-01-01

The modern turbine engine operates in a harsh environment at high speeds and is repeatedly exposed to combined high mechanical and thermal loads. The cumulative effects of these external forces lead to high stresses and strains on the engine components, such as the rotating turbine disks, which may eventually lead to a catastrophic failure if left undetected. The operating environment makes it difficult to use conventional strain gauges, therefore, non-contact strain measurement techniques is of interest to NASA and the turbine engine community. This presentation describes one such approach; the use of cross correlation analysis to measure strain experienced by the engine turbine disk with the goal of assessing potential faults and damage.

Advanced active health monitoring system of liquid rocket engines

NASA Astrophysics Data System (ADS)

Qing, Xinlin P.; Wu, Zhanjun; Beard, Shawn; Chang, Fu-Kuo

2008-11-01

An advanced SMART TAPE system has been developed for real-time in-situ monitoring and long term tracking of structural integrity of pressure vessels in liquid rocket engines. The practical implementation of the structural health monitoring (SHM) system including distributed sensor network, portable diagnostic hardware and dedicated data analysis software is addressed based on the harsh operating environment. Extensive tests were conducted on a simulated large booster LOX-H2 engine propellant duct to evaluate the survivability and functionality of the system under the operating conditions of typical liquid rocket engines such as cryogenic temperature, vibration loads. The test results demonstrated that the developed SHM system could survive the combined cryogenic temperature and vibration environments and effectively detect cracks as small as 2 mm.

Alpha-ray spectrometry at high temperature by using a compound semiconductor detector.

PubMed

Ha, Jang Ho; Kim, Han Soo

2013-11-01

The use of conventional radiation detectors in harsh environments is limited by radiation damage to detector materials and by temperature constraints. We fabricated a wide-band gap semiconductor radiation detector based on silicon carbide. All the detector components were considered for an application in a high temperature environment like a nuclear reactor core. The radiation response, especially to alpha particles, was measured using an (241)Am source at variable operating voltages at room temperature in the air. The temperature on detector was controlled from 30°C to 250°C. The alpha-particle spectra were measured at zero bias operation. Even though the detector is operated at high temperature, the energy resolution as a function of temperature is almost constant within 3.5% deviation. Copyright © 2013 Elsevier Ltd. All rights reserved.

Harsh Parenting in Relation to Child Emotion Regulation and Aggression

PubMed Central

Chang, Lei; Schwartz, David; Dodge, Kenneth A.; McBride-Chang, Catherine

2009-01-01

This study presents a model of harsh parenting that has an indirect effect, as well as a direct effect, on child aggression in the school environment through the mediating process of child emotion regulation. Tested on a sample of 325 Chinese children and their parents, the model showed adequate goodness of fit. Also investigated were interaction effects between parents’ and children’s gender. Mothers’ harsh parenting affected child emotion regulation more strongly than fathers’, whereas harsh parenting emanating from fathers had a stronger effect on child aggression. Fathers’ harsh parenting also affected sons more than daughters, whereas there was no gender differential effect with mothers’ harsh parenting. These results are discussed with an emphasis on negative emotionality as a potentially common cause of family perturbations, including parenting and child adjustment problems. PMID:14640808

Angry Responses to Infant Challenges: Parent, Marital, and Child Genetic Factors Associated with Harsh Parenting

PubMed Central

Hajal, Nastassia J.; Neiderhiser, Jenae M.; Moore, Ginger A.; Leve, Leslie D.; Shaw, Daniel S.; Harold, Gordon T.; Scaramella, Laura V.; Ganiban, Jody M.; Reiss, David

2014-01-01

This study examined genetic and environmental influences on harsh parenting of 9-month-olds. We examined whether positive child-, parent-, and family-level characteristics were associated with harsh parenting in addition to negative characteristics. We were particularly interested in examining evocative gene-environment correlation (rGE) by testing the effect of birth parent temperament on adoptive parents’ harsh parenting. Additionally, we examined associations among adoptive parents’ own temperaments, their marital relationship quality, and harsh parenting. Adoptive fathers’ (but not adoptive mothers’) harsh parenting was inversely related to an index of birth mother positive temperament (reward dependence), indicating evocative rGE. Higher marital quality was associated with less harsh parenting, but only for adoptive fathers. Adoptive parents’ negative temperamental characteristics (harm avoidance) were related to hostile parenting. Findings suggest the importance of enhancing positive family characteristics in addition to mitigating negative characteristics, as well as engaging multiple levels of the family system to prevent harsh parenting. PMID:25641632

Wireless sensor platform for harsh environments

NASA Technical Reports Server (NTRS)

Garverick, Steven L. (Inventor); Yu, Xinyu (Inventor); Toygur, Lemi (Inventor); He, Yunli (Inventor)

2009-01-01

Reliable and efficient sensing becomes increasingly difficult in harsher environments. A sensing module for high-temperature conditions utilizes a digital, rather than analog, implementation on a wireless platform to achieve good quality data transmission. The module comprises a sensor, integrated circuit, and antenna. The integrated circuit includes an amplifier, A/D converter, decimation filter, and digital transmitter. To operate, an analog signal is received by the sensor, amplified by the amplifier, converted into a digital signal by the A/D converter, filtered by the decimation filter to address the quantization error, and output in digital format by the digital transmitter and antenna.

Strategic Adaptation of SCA for STRS

NASA Technical Reports Server (NTRS)

Quinn, Todd; Kacpura, Thomas

2007-01-01

The Space Telecommunication Radio System (STRS) architecture is being developed to provide a standard framework for future NASA space radios with greater degrees of interoperability and flexibility to meet new mission requirements. The space environment imposes unique operational requirements with restrictive size, weight, and power constraints that are significantly smaller than terrestrial-based military communication systems. With the harsh radiation environment of space, the computing and processing resources are typically one or two generations behind current terrestrial technologies. Despite these differences, there are elements of the SCA that can be adapted to facilitate the design and implementation of the STRS architecture.

Improvement of High-Temperature Stability of Al₂O₃/Pt/ZnO/Al₂O₃ Film Electrode for SAW Devices by Using Al₂O₃ Barrier Layer.

PubMed

Liu, Xingpeng; Peng, Bin; Zhang, Wanli; Zhu, Jun; Liu, Xingzhao; Wei, Meng

2017-12-01

In order to develop film electrodes for the surface acoustic wave (SAW) devices operating in harsh high-temperature environments, novel Al₂O₃/Pt/ZnO/Al₂O₃ multilayered film electrodes were prepared by laser molecular beam epitaxy (LMBE) at 150 °C. The first Al₂O₃ layer was used as a barrier layer to prevent the diffusion of Ga, La, and Si atoms from the La₃Ga₅SiO 14 (LGS) substrate to the film electrode and thus improved the crystalline quality of ZnO and Pt films. It was found that the resistance of the Al₂O₃/Pt/ZnO/Al₂O₃ electrode did not vary up to a temperature of 1150 °C, suggesting a high reliability of electrode under harsh high-temperature environments. The mechanism of the stable resistance of the Al₂O₃/Pt/ZnO/Al₂O₃ film electrodes at high temperature was investigated by analyzing its microstructure. The proposed Al₂O₃/Pt/ZnO/Al₂O₃ film electrode has great potential for application in high-temperature SAW devices.

HARSHNESS: CHARACTERIZATION OF INTERMITTENT STREAM HABITAT OVER SPACE AND TIME

EPA Science Inventory

Frequently disturbed environments, such as intermittent streams, are ecologically useful for studying how disturbance characteristics (e.g., frequency, magnitude) affect community structure and succession. A harshness index summarizing spatial and temporal characteristics of pra...

Tribometer for Ultra Harsh Environments

DTIC Science & Technology

2006-05-01

aware that notwithstanding any other provision of law, no person shall be subject to any penalty for failing to comply with a collection of infonmation...harsh environments 1S. SUBJECT TERMS 16. SECURITY CLASSIFICATION OF : 17. LIMITATION OF 18. NUMBER 19a. NAME OF RESPONSIBLE PERSON a . REPORT b...can provide a pathway for the collaboration of several universities, government laboratories and industry to evaluate next generation of aerospace

Miniature Robotic Submarine for Exploring Harsh Environments

NASA Technical Reports Server (NTRS)

Behar, Alberto; Bruhn, Fredrik; Carsey, Frank

2004-01-01

The miniature autonomous submersible explorer (MASE) has been proposed as a means of scientific exploration -- especially, looking for signs of life -- in harsh, relatively inaccessible underwater environments. Basically, the MASE would be a small instrumented robotic submarine (see figure) that could launch itself or could be launched from another vehicle. Examples of environments that might be explored by use of the MASE include subglacial lakes, deep-ocean hydrothermal vents, acidic or alkaline lakes, brine lenses in permafrost, and ocean regions under Antarctic ice shelves.

AOCS operations preparation for the BepiColombo mission to mercury

NASA Astrophysics Data System (ADS)

Steiger, C.; Altay, A.; Montagnon, E.; Companys, V.

2018-06-01

The 2018 ESA/JAXA BepiColombo mission to Mercury features a complex modular design, with two scientific Mercury orbiters and a cruise module. The spacecraft (S/C) and mission design lead to a number of challenges for the attitude and orbit control system (AOCS), including electric propulsion usage during cruise to Mercury, AOCS capability to deal with several S/C configurations, and strict attitude constraints owing to the harsh thermal environment. This paper presents the activities for AOCS operations preparation by ESA/ESOC, covering the current preparation status as well as an outlook on upcoming activities before launch.

Cryogenic Behavior of the High Temperature Crystal Oscillator PX-570

NASA Technical Reports Server (NTRS)

Patterson, Richard; Hammoud, Ahmad; Scherer, Steven

2011-01-01

Microprocessors, data-acquisition systems, and electronic controllers usually require timing signals for proper and accurate operation. These signals are, in most cases, provided by circuits that utilize crystal oscillators due to availability, cost, ease of operation, and accuracy. Stability of these oscillators, i.e. crystal characteristics, is usually governed, amongst other things, by the ambient temperature. Operation of these devices under extreme temperatures requires, therefore, the implementation of some temperature-compensation mechanism either through the manufacturing process of the oscillator part or in the design of the circuit to maintain stability as well as accuracy. NASA future missions into deep space and planetary exploration necessitate operation of electronic instruments and systems in environments where extreme temperatures along with wide-range thermal swings are countered. Most of the commercial devices are very limited in terms of their specified operational temperature while very few custom-made and military-grade parts have the ability to operate in a slightly wider range of temperature. Thus, it is becomes mandatory to design and develop circuits that are capable of operation efficiently and reliably under the space harsh conditions. This report presents the results obtained on the evaluation of a new (COTS) commercial-off-the-shelf crystal oscillator under extreme temperatures. The device selected for evaluation comprised of a 10 MHz, PX-570-series crystal oscillator. This type of device was recently introduced by Vectron International and is designed as high temperature oscillator [1]. These parts are fabricated using proprietary manufacturing processes designed specifically for high temperature and harsh environment applications [1]. The oscillators have a wide continuous operating temperature range; making them ideal for use in military and aerospace industry, industrial process control, geophysical fields, avionics, and engine control. They exhibit low jitter and phase noise, consume little power, and are suited for high shock and vibration applications. The unique package design of these crystal oscillators offers a small ceramic package footprint, as well as providing both through-hole mounting and surface mount options.

RASSOR - Regolith Advanced Surface Systems Operations Robot

NASA Technical Reports Server (NTRS)

Gill, Tracy R.; Mueller, Rob

2015-01-01

The Regolith Advanced Surface Systems Operations Robot (RASSOR) is a lightweight excavator for mining in reduced gravity. RASSOR addresses the need for a lightweight (<100 kg) robot that is able to overcome excavation reaction forces while operating in reduced gravity environments such as the moon or Mars. A nominal mission would send RASSOR to the moon to operate for five years delivering regolith feedstock to a separate chemical plant, which extracts oxygen from the regolith using H2 reduction methods. RASSOR would make 35 trips of 20 kg loads every 24 hours. With four RASSORs operating at one time, the mission would achieve 10 tonnes of oxygen per year (8 t for rocket propellant and 2 t for life support). Accessing craters in space environments may be extremely hard and harsh due to volatile resources - survival is challenging. New technologies and methods are required. RASSOR is a product of KSC Swamp Works which establishes rapid, innovative and cost effective exploration mission solutions by leveraging partnerships across NASA, industry and academia.

Chemical Aging of Environmentally Friendly Cleaners

NASA Technical Reports Server (NTRS)

Biegert, L. L.; Evans, K. B.; Olsen, B. D.; Weber, B. L.

2001-01-01

Use of cleaners in the manufacturing area demands bottles that will hold a sufficient amount of material and allow for easy and controlled dispensing by the operator without contamination or material leaching from the bottle. The manufacturing storage conditions are also a factor that may affect cleaner chemical integrity and its potential to leave a residue on the part. A variety of squeeze bottles stored in mild (72 F, 10% R.H., dark) and harsh (105 F, 50% R.H., fluorescent lighting) conditions were evaluated to determine the effect of environment and bottle exposure on ozone depleting chemicals (ODC) cleaners chemical composition. Low Density Polyethylene (LDPE) bottles were found to be quite permeable to all the cleaners evaluated in this study indicating this bottle type should not be used in the manufacturing area. Fluorinated Polyethylene (FLPE) bottles showed little cleaner loss and change in cleaner chemical composition over time suggesting these bottles would be acceptable for use. Chemical analysis indicates limonene containing cleaners show increased non-volatile residue (NVR) content with storage under harsh conditions. Some cleaners use BHT (butylated hydroxytoluene) as stabilizer and to protect against limonene oxidation. Under harsh conditions, BHT was quickly depleted resulting in higher NVR levels.

Chemical Aging of Environmentally Friendly Cleaners

NASA Technical Reports Server (NTRS)

Evans, K.; Biegert, L.; Olsen, B.; Weber, B.; McCool, Alex (Technical Monitor)

2001-01-01

Use of cleaners in the manufacturing area demands bottles that will hold a sufficient amount of material and allow for easy and controlled dispensing by the operator without contamination or material leaching from the bottle. The manufacturing storage conditions are also a factor that may affect cleaner chemical integrity and its potential to leave a residue on the part. A variety of squeeze bottles stored in mild (72 F, 10 % R.H., dark) and harsh (105 F, 50 % R.H., fluorescent lighting) conditions were evaluated to determine the effect of environment and bottle exposure on the chemical composition of TCA (1,1,1 trichloroethane) replacement solvents. Low Density Polyethylene (LDPE) bottles were found to be quite permeable to all the cleaners evaluated in this study indicating this bottle type should not be used in the manufacturing area. Fluorinated Polyethylene (FLPE) bottles showed little cleaner loss and change in cleaner chemical composition over time suggesting these bottles would be acceptable for use. Chemical analysis indicates limonene-containing cleaners show increased non-volatile residue (NVR) content with storage under harsh conditions. Some cleaners use BHT (butylated hydroxytoluene) as stabilizer and to protect against limonene oxidation. Under harsh conditions, BHT was quickly depleted resulting in higher NVR levels.

Review and perspective: Sapphire optical fiber cladding development for harsh environment sensing

NASA Astrophysics Data System (ADS)

Chen, Hui; Buric, Michael; Ohodnicki, Paul R.; Nakano, Jinichiro; Liu, Bo; Chorpening, Benjamin T.

2018-03-01

The potential to use single-crystal sapphire optical fiber as an alternative to silica optical fibers for sensing in high-temperature, high-pressure, and chemically aggressive harsh environments has been recognized for several decades. A key technological barrier to the widespread deployment of harsh environment sensors constructed with sapphire optical fibers has been the lack of an optical cladding that is durable under these conditions. However, researchers have not yet succeeded in incorporating a high-temperature cladding process into the typical fabrication process for single-crystal sapphire fibers, which generally involves seed-initiated fiber growth from the molten oxide state. While a number of advances in fabrication of a cladding after fiber-growth have been made over the last four decades, none have successfully transitioned to a commercial manufacturing process. This paper reviews the various strategies and techniques for fabricating an optically clad sapphire fiber which have been proposed and explored in published research. The limitations of current approaches and future prospects for sapphire fiber cladding are discussed, including fabrication methods and materials. The aim is to provide an understanding of the past research into optical cladding of sapphire fibers and to assess possible material systems for future research on this challenging problem for harsh environment sensors.

High-Intensity Radiated Field Fault-Injection Experiment for a Fault-Tolerant Distributed Communication System

NASA Technical Reports Server (NTRS)

Yates, Amy M.; Torres-Pomales, Wilfredo; Malekpour, Mahyar R.; Gonzalez, Oscar R.; Gray, W. Steven

2010-01-01

Safety-critical distributed flight control systems require robustness in the presence of faults. In general, these systems consist of a number of input/output (I/O) and computation nodes interacting through a fault-tolerant data communication system. The communication system transfers sensor data and control commands and can handle most faults under typical operating conditions. However, the performance of the closed-loop system can be adversely affected as a result of operating in harsh environments. In particular, High-Intensity Radiated Field (HIRF) environments have the potential to cause random fault manifestations in individual avionic components and to generate simultaneous system-wide communication faults that overwhelm existing fault management mechanisms. This paper presents the design of an experiment conducted at the NASA Langley Research Center's HIRF Laboratory to statistically characterize the faults that a HIRF environment can trigger on a single node of a distributed flight control system.

Force instrumentation for cryogenic wind tunnels using one-piece strain-gage balances

NASA Technical Reports Server (NTRS)

Ferris, A. T.

1980-01-01

The use of cryogenic temperatures in wind tunnels to achieve high Reynolds numbers has imposed a harsh operating environment on the force balance. Laboratory tests were conducted to study the effect cryogenic temperatures have on balance materials, gages, wiring, solder, adhesives, and moisture proofing. Wind tunnel tests were conducted using a one piece three component balance to verify laboratory results. These initial studies indicate that satisfactory force data can be obtained under steady state conditions.

Protocol for communications in potentially noisy environments

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

Boyd, Gerlad M.; Farrow, Jeffrey

2016-02-09

A communications protocol that is designed for transmission of data in networks that are subjected to harsh conditions is described herein. A network includes a plurality of devices, where the devices comprise respective nodes. The nodes are in communication with one another by way of a central network hub. The protocol causes the nodes to transmit data over a network bus at different data rates depending upon whether the nodes are operating normally or an arbitration procedure has been invoked.

Silicon Carbide Solar Cells Investigated

NASA Technical Reports Server (NTRS)

Bailey, Sheila G.; Raffaelle, Ryne P.

2001-01-01

The semiconductor silicon carbide (SiC) has long been known for its outstanding resistance to harsh environments (e.g., thermal stability, radiation resistance, and dielectric strength). However, the ability to produce device-quality material is severely limited by the inherent crystalline defects associated with this material and their associated electronic effects. Much progress has been made recently in the understanding and control of these defects and in the improved processing of this material. Because of this work, it may be possible to produce SiC-based solar cells for environments with high temperatures, light intensities, and radiation, such as those experienced by solar probes. Electronics and sensors based on SiC can operate in hostile environments where conventional silicon-based electronics (limited to 350 C) cannot function. Development of this material will enable large performance enhancements and size reductions for a wide variety of systems--such as high-frequency devices, high-power devices, microwave switching devices, and high-temperature electronics. These applications would supply more energy-efficient public electric power distribution and electric vehicles, more powerful microwave electronics for radar and communications, and better sensors and controls for cleaner-burning, more fuel-efficient jet aircraft and automobile engines. The 6H-SiC polytype is a promising wide-bandgap (Eg = 3.0 eV) semiconductor for photovoltaic applications in harsh solar environments that involve high-temperature and high-radiation conditions. The advantages of this material for this application lie in its extremely large breakdown field strength, high thermal conductivity, good electron saturation drift velocity, and stable electrical performance at temperatures as high as 600 C. This behavior makes it an attractive photovoltaic solar cell material for devices that can operate within three solar radii of the Sun.

Detection of Hidden Hostile/Terrorist Groups in Harsh Territories by Using Animals as Mobile Biological Sensors

PubMed Central

Sahin, Yasar Guneri; Ercan, Tuncay

2008-01-01

Terrorism is the greatest threat to national security and cannot be defeated by conventional military force alone. In critical areas such as Iraq, Afghanistan and Turkey, regular forces cannot reach these hostile/terrorist groups, the instigators of terrorism. These groups have a clear understanding of the relative ineffectiveness of counter-guerrilla operations and rely on guerrilla warfare to avoid major combat as their primary means of continuing the conflict with the governmental structures. In Internal Security Operations, detection of terrorist and hostile groups in their hiding places such as caves, lairs, etc. can only be achieved by professionally trained people such as Special Forces or intelligence units with the necessary experience and tools suitable for collecting accurate information in these often harsh, rugged and mountainous countries. To assist these forces, commercial micro-sensors with wireless interfaces could be utilized to study and monitor a variety of phenomena and environments from a certain distance for military purposes. In order to locate hidden terrorist groups and enable more effective use of conventional military resources, this paper proposes an active remote sensing model implanted into animals capable of living in these environments. By using these mobile sensor devices, improving communications for data transfer from the source, and developing better ways to monitor and detect threats, terrorist ability to carry out attacks can be severely disrupted. PMID:27879941

Detection of Hidden Hostile/Terrorist Groups in Harsh Territories by Using Animals as Mobile Biological Sensors.

PubMed

Sahin, Yasar Guneri; Ercan, Tuncay

2008-07-25

Terrorism is the greatest threat to national security and cannot be defeated by conventional military force alone. In critical areas such as Iraq, Afghanistan and Turkey, regular forces cannot reach these hostile/terrorist groups, the instigators of terrorism. These groups have a clear understanding of the relative ineffectiveness of counter-guerrilla operations and rely on guerrilla warfare to avoid major combat as their primary means of continuing the conflict with the governmental structures. In Internal Security Operations, detection of terrorist and hostile groups in their hiding places such as caves, lairs, etc. can only be achieved by professionally trained people such as Special Forces or intelligence units with the necessary experience and tools suitable for collecting accurate information in these often harsh, rugged and mountainous countries. To assist these forces, commercial micro-sensors with wireless interfaces could be utilized to study and monitor a variety of phenomena and environments from a certain distance for military purposes. In order to locate hidden terrorist groups and enable more effective use of conventional military resources, this paper proposes an active remote sensing model implanted into animals capable of living in these environments. By using these mobile sensor devices, improving communications for data transfer from the source, and developing better ways to monitor and detect threats, terrorist ability to carry out attacks can be severely disrupted.

Evaluation of Advanced COTS Passive Devices for Extreme Temperature Operation

NASA Technical Reports Server (NTRS)

Patterson, Richard; Hammoud, Ahmad; Dones, Keishla R.

2009-01-01

Electronic sensors and circuits are often exposed to extreme temperatures in many of NASA deep space and planetary surface exploration missions. Electronics capable of operation in harsh environments would be beneficial as they simplify overall system design, relax thermal management constraints, and meet operational requirements. For example, cryogenic operation of electronic parts will improve reliability, increase energy density, and extend the operational lifetimes of space-based electronic systems. Similarly, electronic parts that are able to withstand and operate efficiently in high temperature environments will negate the need for thermal control elements and their associated structures, thereby reducing system size and weight, enhancing its reliability, improving its efficiency, and reducing cost. Passive devices play a critical role in the design of almost all electronic circuitry. To address the needs of systems for extreme temperature operation, some of the advanced and most recently introduced commercial-off-the-shelf (COTS) passive devices, which included resistors and capacitors, were examined for operation under a wide temperature regime. The types of resistors investigated included high temperature precision film, general purpose metal oxide, and wirewound.

Why NASA and the Space Electronics Community Cares About Cyclotrons

NASA Technical Reports Server (NTRS)

LaBel, Kenneth A.

2017-01-01

NASA and the space community are faced with the harsh reality of operating electronic systems in the space radiation environment. Systems need to work reliably (as expected for as long as expected) and be available during critical operations such as docking or firing a thruster. This talk will provide a snapshot of the import of ground-based research on the radiation performance of electronics. Discussion topics include: 1) The space radiation environment hazard, 2) Radiation effects on electronics, 3) Simulation of effects with cyclotrons (and other sources), 4) Risk prediction for space missions, and, 5) Real-life examples of both ground-based testing and space-based anomalies and electronics performance. The talk will conclude with a discussion of the current state of radiation facilities in North America for ground-based electronics testing.

High Temperature Capacitive Pressure Sensor Employing a SiC Based Ring Oscillator

NASA Technical Reports Server (NTRS)

Meredith, Roger D.; Neudeck, Philip G.; Ponchak, George E.; Beheim, Glenn M.; Scardelletti, Maximilian; Jordan, Jennifer L.; Chen, Liang-Yu; Spry, David J.; Krawowski, Michael J.; Hunter, Gary W.

2011-01-01

In an effort to develop harsh environment electronic and sensor technologies for aircraft engine safety and monitoring, we have used capacitive-based pressure sensors to shift the frequency of a SiC-electronics-based oscillator to produce a pressure-indicating signal that can be readily transmitted, e.g. wirelessly, to a receiver located in a more benign environment. Our efforts target 500 C, a temperature well above normal operating conditions of commercial circuits but within areas of interest in aerospace engines, deep mining applications and for future missions to the Venus atmosphere. This paper reports for the first time a ring oscillator circuit integrated with a capacitive pressure sensor, both operating at 500 C. This demonstration represents a significant step towards a wireless pressure sensor that can operate at 500 C and confirms the viability of 500 C electronic sensor systems.

Stable Electrical Operation of 6H-SiC JFETs and ICs for Thousands of Hours at 500 C

NASA Technical Reports Server (NTRS)

Neudeck, Philip G.; Spry, David J.; Chen, Liang-Yu; Beheim, Glenn M.; Okojie, Robert S.; Chang, Carl W.; Meredith, Roger D.; Ferrier, Terry L.; Evans, Laura J.; Krasowski, Michael J.;

Surface Support Systems for Co-Operative and Integrated Human/Robotic Lunar Exploration

NASA Technical Reports Server (NTRS)

Mueller, Robert P.

2006-01-01

Human and robotic partnerships to realize space goals can enhance space missions and provide increases in human productivity while decreasing the hazards that the humans are exposed to. For lunar exploration, the harsh environment of the moon and the repetitive nature of the tasks involved with lunar outpost construction, maintenance and operation as well as production tasks associated with in-situ resource utilization, make it highly desirable to use robotic systems in co-operation with human activity. A human lunar outpost is functionally examined and concepts for selected human/robotic tasks are discussed in the context of a lunar outpost which will enable the presence of humans on the moon for extended periods of time.

Use telecommunications for real-time process control

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

Zilberman, I.; Bigman, J.; Sela, I.

1996-05-01

Process operators design real-time accurate information to monitor and control product streams and to optimize unit operations. The challenge is how to cost-effectively install sophisticated analytical equipment in harsh environments such as process areas and maintain system reliability. Incorporating telecommunications technology with near infrared (NIR) spectroscopy may be the bridge to help operations achieve their online control goals. Coupling communications fiber optics with NIR analyzers enables the probe and sampling system to remain in the field and crucial analytical equipment to be remotely located in a general purpose area without specialized protection provisions. The case histories show how two refineriesmore » used NIR spectroscopy online to track octane levels for reformate streams.« less

Electromagnetic Acoustic Transducers for Robotic Nondestructive Inspection in Harsh Environments

PubMed Central

Choi, Sungho; Cho, Hwanjeong; Lindsey, Matthew S.; Lissenden, Cliff J.

2018-01-01

Elevated temperature, gamma radiation, and geometric constraints inside dry storage casks for spent nuclear fuel represent a harsh environment for nondestructive inspection of the cask and require that the inspection be conducted with a robotic system. Electromagnetic acoustic transducers (EMATs) using non-contact ultrasonic transduction based on the Lorentz force to excite/receive ultrasonic waves are suited for use in the robotic inspection. Periodic permanent magnet EMATs that actuate/receive shear horizontal guided waves are developed for application to robotic nondestructive inspection of stress corrosion cracks in the heat affected zone of welds in stainless steel dry storage canisters. The EMAT’s components are carefully selected in consideration of the inspection environment, and tested under elevated temperature and gamma radiation doses up to 177 °C and 5920 krad, respectively, to evaluate the performance of the EMATs under realistic environmental conditions. The effect of gamma radiation is minimal, but the EMAT’s performance is affected by temperatures above 121 °C due to the low Curie temperature of the magnets. Different magnets are needed to operate at 177 °C. The EMAT’s capability to detect notches is also evaluated from B-scan measurements on 304 stainless steel welded plate containing surface-breaking notches. PMID:29324721

Extreme Environment Sensing Using Femtosecond Laser-Inscribed Fiber Bragg Gratings

PubMed Central

Grobnic, Dan; Hnatovsky, Cyril; Walker, Robert B.; Coulas, David; Ding, Huimin

2017-01-01

The femtosecond laser-induced fiber Bragg grating is an effective sensor technology that can be deployed in harsh environments. Depending on the optical fiber chosen and the inscription parameters that are used, devices suitable for high temperature, pressure, ionizing radiation and strain sensor applications are possible. Such devices are appropriate for aerospace or energy production applications where there is a need for components, instrumentation and controls that can function in harsh environments. This paper will present a review of some of the more recent developments in this field. PMID:29240721

Reliability of solid-state lighting electrical drivers subjected to WHTOL accelerated aging

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

Lall, Pradeep; Sakalauku, Peter; Davis, Lynn

An investigation of a solid-state lighting (SSL) luminaire with the focus on the electronic driver which has been exposed to a standard wet hot temperature operating life (WHTOL) of 85% RH and 85°C in order to assess reliability of prolonged exposer to a harsh environment has been conducted. SSL luminaires are beginning introduced as head lamps in some of today's luxury automobiles and may also be fulfilling a variety of important outdoor applications such as overhead street lamps, traffic signals and landscape lighting. SSL luminaires in these environments are almost certain to encounter excessive moisture from humidity and high temperaturesmore » for a persistent period of time. The lack of accelerated test methods for LEDs to assess long-term reliability prior to introduction into the marketplace, a need for SSL physics based PHM modeling indicators for assessment and prediction of LED life, as well as the U.S. Department of Energy's R&D roadmap to replace todays lighting with SSL luminaires makes it important to increase the understanding of the reliability of SSL devices, specifically, in harsh environment applications. In this work, a set of SSL electrical drivers were investigated to determine failure mechanisms that occur during prolonged harsh environment applications. Each driver consists of four aluminum electrolytic capacitors (AECs) of three different types and was considered the weakest component inside the SSL electrical driver. The reliability of the electrical driver was assessed by monitoring the change in capacitance and the change in equivalent series resistance for each AEC, as well as monitoring the luminous flux of the SSL luminaire or the output of the electrical driver. The luminous flux of a pristine SSL electrical driver was also monitored in order to detect minute changes in the electrical drivers output and to aid in the investigation of the SSL luminaires reliability. The failure mechanisms of the electrical drivers have been determined and are presented in this paper.« less

Silicon Carbide Sensors and Electronics for Harsh Environment Applications

NASA Technical Reports Server (NTRS)

Evans, Laura J.

2007-01-01

Silicon carbide (SiC) semiconductor has been studied for electronic and sensing applications in extreme environment (high temperature, extreme vibration, harsh chemical media, and high radiation) that is beyond the capability of conventional semiconductors such as silicon. This is due to its near inert chemistry, superior thermomechanical and electronic properties that include high breakdown voltage and wide bandgap. An overview of SiC sensors and electronics work ongoing at NASA Glenn Research Center (NASA GRC) will be presented. The main focus will be two technologies currently being investigated: 1) harsh environment SiC pressure transducers and 2) high temperature SiC electronics. Work highlighted will include the design, fabrication, and application of SiC sensors and electronics, with recent advancements in state-of-the-art discussed as well. These combined technologies are studied for the goal of developing advanced capabilities for measurement and control of aeropropulsion systems, as well as enhancing tools for exploration systems.

TransFormers for Ensuring Long-Term Operations in Lunar Extreme Environments

NASA Technical Reports Server (NTRS)

Mantovani, J. G.; Stoica, A.; Alkalai, L.; Wilcox, B.; Quadrelli, M.

2016-01-01

"Surviving Extreme Space Environments" (EE) is one of NASA's Space Technology Grand Challenges. Power generation and thermal control are the key survival ingredients that allow a robotic explorer to cope with the EE using resources available to it, for example, by harvesting the local solar energy or by utilizing an onboard radioisotope thermoelectric generator (RTG). TransFormers (TFs) are a new technology concept designed to transform a localized area within a harsh extreme environment into a survivable micro-environment by projecting energy to the precise location where robots or humans operate. For example, TFs placed at a location on the rim of Shackleton Crater, which is illuminated by solar radiation for most of the year, would be able to reflect solar energy onto robots operating in the dark cold crater. TFs utilize a shape transformation mechanism to un-fold from a compact volume to a large reflective surface, and to control how much-and where-the energy is projected, and by adjusting for the changing position of the sun. TFs would enable in-situ resource utilization (ISRU) activities within locations of high interest that would normally be unreachable because of their extreme environment

Ensuring critical event sequences in high consequence computer based systems as inspired by path expressions

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

Kidd, M.E.C.

1997-02-01

The goal of our work is to provide a high level of confidence that critical software driven event sequences are maintained in the face of hardware failures, malevolent attacks and harsh or unstable operating environments. This will be accomplished by providing dynamic fault management measures directly to the software developer and to their varied development environments. The methodology employed here is inspired by previous work in path expressions. This paper discusses the perceived problems, a brief overview of path expressions, the proposed methods, and a discussion of the differences between the proposed methods and traditional path expression usage and implementation.

Toward remotely controlled planetary rovers.

NASA Technical Reports Server (NTRS)

Moore, J. W.

1972-01-01

Studies of unmanned planetary rovers have emphasized a Mars mission. Relatively simple rovers, weighing about 50 kg and tethered to the lander, may precede semiautonomous roving vehicles. It is conceivable that the USSR will deploy a rover on Mars before Viking lands. The feasibility of the roving vehicle as an explorational tool hinges on its ability to operate for extended periods of time relatively independent of earth, to withstand the harshness of the Martian environment, and to travel hundreds of kilometers independent of the spacecraft that delivers it.

Passive Wireless SAW Sensors for IVHM

NASA Technical Reports Server (NTRS)

Wilson, William C.; Perey, Daniel F.; Atkinson, Gary M.; Barclay, Rebecca O.

2008-01-01

NASA aeronautical programs require integrated vehicle health monitoring (IVHM) to ensure the safety of the crew and the vehicles. Future IVHM sensors need to be small, light weight, inexpensive, and wireless. Surface acoustic wave (SAW) technology meets all of these constraints. In addition it operates in harsh environments and over wide temperature ranges, and it is inherently radiation hardened. This paper presents a survey of research opportunities for universities and industry to develop new sensors that address anticipated IVHM needs for aerospace vehicles. Potential applications of passive wireless SAW sensors from ground testing to high altitude aircraft operations are presented, along with some of the challenges and issues of the technology.

All Fiber-Coupled OH Planar Laser-Induced-Fluorescence (OH-PLIF)-Based Two-Dimensional Thermometry.

PubMed

Hsu, Paul S; Jiang, Naibo; Patnaik, Anil K; Katta, Vish; Roy, Sukesh; Gord, James R

2018-04-01

Two-color, planar laser-induced fluorescence (PLIF)-based two-dimensional (2D) thermometry techniques for reacting flows, which are typically developed in the laboratory conditions, face a stiff challenge in their practical implementation in harsh environments such as combustion rigs. In addition to limited optical access, the critical experimental conditions (i.e., uncontrolled humidity, vibration, and large thermal gradients) often restrict sensitive laser system operation and cause difficulties maintaining beam-overlap. Thus, an all fiber-coupled, two-color OH-PLIF system has been developed, employing two long optical fibers allowing isolation of the laser and signal-collection systems. Two OH-excitation laser beams (∼283 nm and ∼286 nm) are delivered through a common 6 m long, 400 µm core, deep ultraviolet (UV)-enhanced multimode fiber. The fluorescence signal (∼310 nm) is collected by a 3 m long, UV-grade imaging fiber. Proof-of-principle temperature measurements are demonstrated in atmospheric pressure, near adiabatic, CH 4 /O 2 /N 2 jet flames. The effects of the excitation pulse interval on fiber transmission are investigated. The proof-of-principle measurements show significant promise for thermometry in harsh environments such as gas turbine engine tests.

Rugged sensor window materials for harsh environments

NASA Astrophysics Data System (ADS)

Bayya, Shyam; Villalobos, Guillermo; Kim, Woohong; Sanghera, Jasbinger; Hunt, Michael; Aggarwal, Ishwar D.

2014-09-01

There are several military or commercial systems operating in very harsh environments that require rugged windows. On some of these systems, windows become the single point of failure. These applications include sensor or imaging systems, high-energy laser weapons systems, submarine photonic masts, IR countermeasures and missiles. Based on the sea or land or air based platforms the window or dome on these systems must withstand wave slap, underwater or ground based explosions, or survive flight through heavy rain and sand storms while maintaining good optical transmission in the desired wavelength range. Some of these applications still use softer ZnS or fused silica windows because of lack of availability of rugged materials in shapes or sizes required. Sapphire, ALON and spinel are very rugged materials with significantly higher strengths compared to ZnS and fused silica. There have been recent developments in spinel, ALON and sapphire materials to fabricate in large sizes and conformal shapes. We have been developing spinel ceramics for several of these applications. We are also developing β-SiC as a transparent window material as it has higher hardness, strength, and toughness than sapphire, ALON and spinel. This paper gives a summary of our recent findings.

Planetary atmospheres minor species sensor balloon flight test to near space

NASA Astrophysics Data System (ADS)

Peale, Robert E.; Fredricksen, Christopher J.; Muraviev, Andrei V.; Maukonen, Douglas; Quddusi, Hajrah M.; Calhoun, Seth; Colwell, Joshua E.; Lachenmeier, Timothy A.; Dewey, Russell G.; Stern, Alan; Padilla, Sebastian; Bode, Rolfe

2015-05-01

The Planetary Atmospheres Minor Species Sensor (PAMSS) is an intracavity laser absorption spectrometer that uses a mid-infrared quantum cascade laser in an open external cavity for sensing ultra-trace gases with parts-per-billion sensitivity. PAMSS was flown on a balloon by Near Space Corporation from Madras OR to 30 km on 17 July 2014. Based on lessons learned, it was modified and was flown a second time to 32 km by World View Enterprises from Pinal AirPark AZ on 8 March 2015. Successes included continuous operation and survival of software, electronics, optics, and optical alignment during extreme conditions and a rough landing. Operation of PAMSS in the relevant environment of near space has significantly elevated its Technical Readiness Level for trace-gas sensing with potential for planetary and atmospheric science in harsh environments.

Angry responses to infant challenges: parent, marital, and child genetic factors associated with harsh parenting.

PubMed

Hajal, Nastassia; Neiderhiser, Jenae; Moore, Ginger; Leve, Leslie; Shaw, Daniel; Harold, Gordon; Scaramella, Laura; Ganiban, Jody; Reiss, David

2015-01-01

This study examined genetic and environmental influences on harsh parenting of adopted 9-month-olds (N = 503), with an emphasis on positive child-, parent-, and family-level characteristics. Evocative gene-environment correlation (rGE) was examined by testing the effect of both positive and negative indices of birth parent temperament on adoptive parents' harsh parenting. Adoptive fathers' harsh parenting was inversely related to birth mother positive temperament, indicating evocative rGE, as well as to marital quality. Adoptive parents' negative temperamental characteristics were related to hostile parenting for both fathers and mothers. Findings support the importance of enhancing positive family characteristics in addition to mitigating negative characteristics, as well as engaging multiple levels of the family system to prevent harsh parenting. © 2015 The Authors. Child Development © 2015 Society for Research in Child Development, Inc.

Method and apparatus for conducting structural health monitoring in a cryogenic, high vibration environment

NASA Technical Reports Server (NTRS)

Qing, Xinlin (Inventor); Beard, Shawn J. (Inventor); Li, Irene (Inventor)

2013-01-01

Sensors affixed to various such structures, where the sensors can withstand, remain affixed, and operate while undergoing both cryogenic temperatures and high vibrations. In particular, piezoelectric single crystal transducers are utilized, and these sensors are coupled to the structure via a low temperature, heat cured epoxy. This allows the transducers to monitor the structure while the engine is operating, even despite the harsh operating conditions. Aspects of the invention thus allow for real time monitoring and analysis of structures that operate in conditions that previously did not permit such analysis. A further aspect of the invention relates to use of piezoelectric single crystal transducers. In particular, use of such transducers allows the same elements to be used as both sensors and actuators.

photonic sensors review progress of optical fiber sensors and its application in harsh environment

NASA Astrophysics Data System (ADS)

Zhang, Min; Ma, Xiaohong; Wang, Liwei; Lai, Shurong; Zhou, Hongpu; Zhao, Huafeng; Liao, Yanbiao

2011-03-01

Fiber sensors have been developed for industry application with significant advantages. In this paper, Fiber sensors for oil field service and harsh environment monitoring which have been investigated in Tsinghua University are demonstrated. By discussing the requirements of practical applications, the key technologies of long-period fiber grating (LPFG) based fiber sensor, optical spectrum analyzer for oil detection, laser induced breakdown spectroscopy (LIBS) system for soil contamination monitoring, and seismic sensor arrays are described.

Applications of Optical Fiber Assemblies in Harsh Environments, the Journey Past, Present and Future

NASA Technical Reports Server (NTRS)

Ott, Melanie N.; LaRocca, Frank; Thomas, William Joe; Switzer, Robert; Chuska, Richard; Macmurphy, Shawn

2008-01-01

Over the past ten years, NASA has studied the effects of harsh environments on optical fiber assemblies for communication systems, lidar systems, and science missions. The culmination of this has resulted in recent technologies that are unique and tailored to meeting difficult requirements under challenging performance constraints. This presentation will focus on the past mission applications of optical fiber assemblies including; qualification information, lessons learned and new technological advances that will enable the road ahead.

Space shuttle main engine controller

NASA Technical Reports Server (NTRS)

Mattox, R. M.; White, J. B.

1981-01-01

A technical description of the space shuttle main engine controller, which provides engine checkout prior to launch, engine control and monitoring during launch, and engine safety and monitoring in orbit, is presented. Each of the major controller subassemblies, the central processing unit, the computer interface electronics, the input electronics, the output electronics, and the power supplies are described and discussed in detail along with engine and orbiter interfaces and operational requirements. The controller represents a unique application of digital concepts, techniques, and technology in monitoring, managing, and controlling a high performance rocket engine propulsion system. The operational requirements placed on the controller, the extremely harsh operating environment to which it is exposed, and the reliability demanded, result in the most complex and rugged digital system ever designed, fabricated, and flown.

Radiation-Tolerant, SpaceWire-Compatible Switching Fabric

NASA Technical Reports Server (NTRS)

Katzman, Vladimir

2011-01-01

Current and future near-Earth and deep space exploration programs and space defense programs require the development of robust intra-spacecraft serial data transfer electronics that must be reconfigurable, fault-tolerant, and have the ability to operate effectively for long periods of time in harsh environmental conditions. Existing data transfer systems based on state-of-the-art serial data transfer protocols or passive backplanes are slow, power-hungry, and poorly reconfigurable. They provide limited expandability and poor tolerance to radiation effects and total ionizing dose (TID) in particular, which presents harmful threats to modern submicron electronics. This novel approach is based on a standard library of differential cells tolerant to TID, and patented, multi-level serial interface architecture that ensures the reliable operation of serial interconnects without application of a data-strobe or other encoding techniques. This proprietary, high-speed differential interface presents a lowpower solution fully compatible with the SpaceWire (SW) protocol. It replaces a dual data-strobe link with two identical independent data channels, thus improving the system s tolerance to harsh environments through additional double redundancy. Each channel incorporates an automatic line integrity control circuitry that delivers error signals in case of broken or shorted lines.

Electronic Components and Systems for Cryogenic Space Applications

NASA Technical Reports Server (NTRS)

Patterson, R. L.; Hammoud, A.; Dickman, J. E.; Gerber, S.; Elbuluk, M. E.; Overton, E.

2001-01-01

Electronic components and systems capable of operation at cryogenic temperatures are anticipated in many future NASA space missions such as deep space probes and planetary surface exploration. For example, an unheated interplanetary probe launched to explore the rings of Saturn would reach an average temperature near Saturn of about - 183 C. In addition to surviving the deep space harsh environment, electronics capable of low temperature operation would contribute to improving circuit performance, increasing system efficiency, and reducing payload development and launch costs. Terrestrial applications where components and systems must operate in low temperature environments include cryogenic instrumentation, superconducting magnetic energy storage, magnetic levitation transportation system, and arctic exploration. An on-going research and development program at the NASA Glenn Research Center focuses on the development of reliable electronic devices and efficient power systems capable of surviving in low temperature environments. An overview of the program will be presented in this paper. A description of the low temperature test facilities along with selected data obtained from in-house component testing will also be discussed. Ongoing research activities that are being performed in collaboration with various organizations will also be presented.

In-Pile Instrumentation Multi- Parameter System Utilizing Photonic Fibers and Nanovision

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

Burgett, Eric

2015-10-13

An advanced in-pile multi-parameter reactor monitoring system is being proposed in this funding opportunity. The proposed effort brings cutting edge, high fidelity optical measurement systems into the reactor environment in an unprecedented fashion, including in-core, in-cladding and in-fuel pellet itself. Unlike instrumented leads, the proposed system provides a unique solution to a multi-parameter monitoring need in core while being minimally intrusive in the reactor core. Detector designs proposed herein can monitor fuel compression and expansion in both the radial and axial dimensions as well as monitor linear power profiles and fission rates during the operation of the reactor. In additionmore » to pressure, stress, strain, compression, neutron flux, neutron spectra, and temperature can be observed inside the fuel bundle and fuel rod using the proposed system. The proposed research aims at developing radiation-hard, harsh-environment multi-parameter systems for insertion into the reactor environment. The proposed research holds the potential to drastically increase the fidelity and precision of in-core instrumentation with little or no impact in the neutron economy in the reactor environment while providing a measurement system capable of operation for entire operating cycles.« less

Systematic investigation of the optical coatings damages induced in harsh space environment

NASA Astrophysics Data System (ADS)

Corso, Alain Jody; Tessarolo, Enrico; Martucci, Alessandro; Pelizzo, Maria Guglielmina

2017-09-01

The scientific goals required to the next-generation space missions lead the development of innovative instrumentation, conceived to operate in increasingly harsh environments. Optical coatings are among the sub-systems which can highly suffer the agents in such environments. In particular, as recently demonstrated, the accelerated ions and particles can potentially jeopardize the coatings optical performances, with a consequent degradation of the overall functionality of an instrument. Despite its importance, this issue is still poorly investigated. In fact, the fragmentary knowledge of the space environments and the low number of previous ground testing experiments complicates the definition of clear procedures to investigate the behavior of the optical coatings in space. A systematic approach devoted to identify a methodology for the validation of optical coatings under ions irradiation is presented. Monte Carlo simulations are used to evaluate the effects induced by different ion species and energies on both layers and multilayers of different materials, getting an accurate overview of the main criticalities. Such results are then used to plan representative irradiation experiments and the subsequent analysis procedures needed for a proper characterization of the exposed samples. In this paper, a summary of the experiments performed so far is presented. Thanks to these studies we have identified three main damage mechanisms which can be used to explain most of the degradation effects observed when an optical coating is irradiated with low energy particles. A brief discussion of such mechanisms is reported.

Ultrasonic techniques for measuring physical properties of fluids in harsh environments

NASA Astrophysics Data System (ADS)

Pantea, Cristian

Ultrasonic-based measurement techniques, either in the time domain or in the frequency domain, include a wide range of experimental methods for investigating physical properties of materials. This discussion is specifically focused on ultrasonic methods and instrumentation development for the determination of liquid properties at conditions typically found in subsurface environments (in the U.S., more than 80% of total energy needs are provided by subsurface energy sources). Such sensors require materials that can withstand harsh conditions of high pressure, high temperature and corrosiveness. These include the piezoelectric material, electrically conductive adhesives, sensor housings/enclosures, and the signal carrying cables, to name a few. A complete sensor package was developed for operation at high temperatures and pressures characteristic to geothermal/oil-industry reservoirs. This package is designed to provide real-time, simultaneous measurements of multiple physical parameters, such as temperature, pressure, salinity and sound speed. The basic principle for this sensor's operation is an ultrasonic frequency domain technique, combined with transducer resonance tracking. This multipurpose acoustic sensor can be used at depths of several thousand meters, temperatures up to 250 °C, and in a very corrosive environment. In the context of high precision measurement of sound speed, the determination of acoustic nonlinearity of liquids will also be discussed, using two different approaches: (i) the thermodynamic method, in which precise and accurate frequency domain sound speed measurements are performed at high pressure and high temperature, and (ii) a modified finite amplitude method, requiring time domain measurements of the second harmonic at room temperature. Efforts toward the development of an acoustic source of collimated low-frequency (10-150 kHz) beam, with applications in imaging, will also be presented.

Experimental Design for Evaluating Selected Nondestructive Measurement Technologies - Advanced Reactor Technology Milestone: M3AT-16PN2301043

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

Ramuhalli, Pradeep; Hirt, Evelyn H.; Pitman, Stan G.

The harsh environments in advanced reactors (AdvRx) increase the possibility of degradation of safety-critical passive components, and therefore pose a particular challenge for deployment and extended operation of these concepts. Nondestructive evaluation technologies are an essential element for obtaining information on passive component condition in AdvRx, with the development of sensor technologies for nondestructively inspecting AdvRx passive components identified as a key need. Given the challenges posed by AdvRx environments and the potential needs for reducing the burden posed by periodic in-service inspection of hard-to-access and hard-to-replace components, a viable solution may be provided by online condition monitoring of components.more » This report identifies the key challenges that will need to be overcome for sensor development in this context, and documents an experimental plan for sensor development, test, and evaluation. The focus of initial research and development is on sodium fast reactors, with the eventual goal of the research being developing the necessary sensor technology, quantifying sensor survivability and long-term measurement reliability for nondestructively inspecting critical components. Materials for sensor development that are likely to withstand the harsh environments are described, along with a status on the fabrication of reference specimens, and the planned approach for design and evaluation of the sensor and measurement technology.« less

Harsh Climates, Poor Transportation, And Irregular Warfare: Logistical Difficulties From Napoleon To The Soviet - Afghan War That Affect Operational Campaigns

DTIC Science & Technology

2014-04-01

confident about having two operational campaigns in the Iberian Peninsula and Russia where the climate , transportation infrastructure, and threats...campaigns in the Iberian Peninsula and Russia exhibited effects of the harsh climates on logistical effectiveness. The climates in the Iberian Peninsula ...decreasing). The Iberian Peninsula climate consists of vast infertile areas with mountains, hills, and dry regions ill-suited for logistically

Fiber optic controls for aircraft engines - Issues and implications

NASA Technical Reports Server (NTRS)

Dasgupta, Samhita; Poppel, Gary L.; Anderson, William P.

1991-01-01

Some of the issues involved with the application of fiber-optic controls for aircraft engines in the harsh operating environment are addressed, with emphasis on fiber-optic temperature, pressure, position, and speed sensors. Criteria are established to evaluate the optical modulation technique, the sensor/control unit interconnection, and the electrooptic architecture. Single mode and polarization dependent sensor types, sensors which depend on the reflection and/or transmission of light through the engine environment, and intensity-based analog sensors are eliminated as a possible candidate for engine implementation. Fiber-optic harnesses tested for their optical integrity, temperature stability, and mechanical strength, exhibit a capacity to meet mechanical strength requirements and still gain a significant reduction in cable weight.

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

Nabeel Riza

In this program, Nuonics, Inc. has studied the fundamentals of a new Silicon Carbide (SiC) materials-based optical sensor technology suited for extreme environments of coal-fired engines in power production. The program explored how SiC could be used for sensing temperature, pressure, and potential gas species in a gas turbine environment. The program successfully demonstrated the optical designs, signal processing and experimental data for enabling both temperature and pressure sensing using SiC materials. The program via its sub-contractors also explored gas species sensing using SiC, in this case, no clear commercially deployable method was proven. Extensive temperature and pressure measurement datamore » using the proposed SiC sensors was acquired to 1000 deg-C and 40 atms, respectively. Importantly, a first time packaged all-SiC probe design was successfully operated in a Siemens industrial turbine rig facility with the probe surviving the harsh chemical, pressure, and temperature environment during 28 days of test operations. The probe also survived a 1600 deg-C thermal shock test using an industrial flame.« less

Water-Gated n-Type Organic Field-Effect Transistors for Complementary Integrated Circuits Operating in an Aqueous Environment.

PubMed

Porrazzo, Rossella; Luzio, Alessandro; Bellani, Sebastiano; Bonacchini, Giorgio Ernesto; Noh, Yong-Young; Kim, Yun-Hi; Lanzani, Guglielmo; Antognazza, Maria Rosa; Caironi, Mario

2017-01-31

The first demonstration of an n-type water-gated organic field-effect transistor (WGOFET) is here reported, along with simple water-gated complementary integrated circuits, in the form of inverting logic gates. For the n-type WGOFET active layer, high-electron-affinity organic semiconductors, including naphthalene diimide co-polymers and a soluble fullerene derivative, have been compared, with the latter enabling a high electric double layer capacitance in the range of 1 μF cm -2 in full accumulation and a mobility-capacitance product of 7 × 10 -3 μF/V s. Short-term stability measurements indicate promising cycling robustness, despite operating the device in an environment typically considered harsh, especially for electron-transporting organic molecules. This work paves the way toward advanced circuitry design for signal conditioning and actuation in an aqueous environment and opens new perspectives in the implementation of active bio-organic interfaces for biosensing and neuromodulation.

A Silicon Carbide Wireless Temperature Sensing System for High Temperature Applications

PubMed Central

Yang, Jie

2013-01-01

In this article, an extreme environment-capable temperature sensing system based on state-of-art silicon carbide (SiC) wireless electronics is presented. In conjunction with a Pt-Pb thermocouple, the SiC wireless sensor suite is operable at 450 °C while under centrifugal load greater than 1,000 g. This SiC wireless temperature sensing system is designed to be non-intrusively embedded inside the gas turbine generators, acquiring the temperature information of critical components such as turbine blades, and wirelessly transmitting the information to the receiver located outside the turbine engine. A prototype system was developed and verified up to 450 °C through high temperature lab testing. The combination of the extreme temperature SiC wireless telemetry technology and integrated harsh environment sensors will allow for condition-based in-situ maintenance of power generators and aircraft turbines in field operation, and can be applied in many other industries requiring extreme environment monitoring and maintenance. PMID:23377189

Water-Gated n-Type Organic Field-Effect Transistors for Complementary Integrated Circuits Operating in an Aqueous Environment

PubMed Central

2017-01-01

The first demonstration of an n-type water-gated organic field-effect transistor (WGOFET) is here reported, along with simple water-gated complementary integrated circuits, in the form of inverting logic gates. For the n-type WGOFET active layer, high-electron-affinity organic semiconductors, including naphthalene diimide co-polymers and a soluble fullerene derivative, have been compared, with the latter enabling a high electric double layer capacitance in the range of 1 μF cm–2 in full accumulation and a mobility–capacitance product of 7 × 10–3 μF/V s. Short-term stability measurements indicate promising cycling robustness, despite operating the device in an environment typically considered harsh, especially for electron-transporting organic molecules. This work paves the way toward advanced circuitry design for signal conditioning and actuation in an aqueous environment and opens new perspectives in the implementation of active bio-organic interfaces for biosensing and neuromodulation. PMID:28180187

Enabling aspects of fiber optic acoustic sensing in harsh environments

NASA Astrophysics Data System (ADS)

Saxena, Indu F.

2013-05-01

The advantages of optical fiber sensing in harsh electromagnetic as well as physical stress environments make them uniquely suited for structural health monitoring and non-destructive testing. In addition to aerospace applications they are making a strong footprint in geophysical monitoring and exploration applications for higher temperature and pressure environments, due to the high temperature resilience of fused silica glass sensors. Deeper oil searches and geothermal exploration and harvesting are possible with these novel capabilities. Progress in components and technologies that are enabling these systems to be fieldworthy are reviewed and emerging techniques summarized that could leapfrog the system performance and reliability.

Secure Infant-Mother Attachment Buffers the Effect of Early-Life Stress on Age of Menarche.

PubMed

Sung, Sooyeon; Simpson, Jeffry A; Griskevicius, Vladas; Kuo, Sally I-Chun; Schlomer, Gabriel L; Belsky, Jay

2016-05-01

Prior research indicates that being reared in stressful environments is associated with earlier onset of menarche in girls. In this research, we examined (a) whether these effects are driven by exposure to certain dimensions of stress (harshness or unpredictability) during the first 5 years of life and (b) whether the negative effects of stress on the timing of menarche are buffered by secure infant-mother attachment. Results revealed that (a) exposure to greater harshness (but not unpredictability) during the first 5 years of life predicted earlier menarche and (b) secure infant-mother attachment buffered girls from this effect of harsh environments. By connecting attachment research to its evolutionary foundations, these results illuminate how environmental stressors and relationships early in life jointly affect pubertal timing. © The Author(s) 2016.

Lightweight Modular Instrumentation for Planetary Applications

NASA Technical Reports Server (NTRS)

Joshi, P. B.

1993-01-01

An instrumentation, called Space Active Modular Materials ExperimentS (SAMMES), is developed for monitoring the spacecraft environment and for accurately measuring the degradation of space materials in low earth orbit (LEO). The SAMMES architecture concept can be extended to instrumentation for planetary exploration, both on spacecraft and in situ. The operating environment for planetary application will be substantially different, with temperature extremes and harsh solar wind and cosmic ray flux on lunar surfaces and temperature extremes and high winds on venusian and Martian surfaces. Moreover, instruments for surface deployment, which will be packaged in a small lander/rover (as in MESUR, for example), must be extremely compact with ultralow power and weight. With these requirements in mind, the SAMMES concept was extended to a sensor/instrumentation scheme for the lunar and Martian surface environment.

Low Temperature Testing of a Radiation Hardened CMOS 8-Bit Flash Analog-to-Digital (A/D) Converter

NASA Technical Reports Server (NTRS)

Gerber, Scott S.; Hammond, Ahmad; Elbuluk, Malik E.; Patterson, Richard L.; Overton, Eric; Ghaffarian, Reza; Ramesham, Rajeshuni; Agarwal, Shri G.

2001-01-01

Power processing electronic systems, data acquiring probes, and signal conditioning circuits are required to operate reliably under harsh environments in many of NASA:s missions. The environment of the space mission as well as the operational requirements of some of the electronic systems, such as infrared-based satellite or telescopic observation stations where cryogenics are involved, dictate the utilization of electronics that can operate efficiently and reliably at low temperatures. In this work, radiation-hard CMOS 8-bit flash A/D converters were characterized in terms of voltage conversion and offset in the temperature range of +25 to -190 C. Static and dynamic supply currents, ladder resistance, and gain and offset errors were also obtained in the temperature range of +125 to -190 C. The effect of thermal cycling on these properties for a total of ten cycles between +80 and - 150 C was also determined. The experimental procedure along with the data obtained are reported and discussed in this paper.

Income and children's behavioral functioning: a sequential mediation analysis.

PubMed

Shelleby, Elizabeth C; Votruba-Drzal, Elizabeth; Shaw, Daniel S; Dishion, Thomas J; Wilson, Melvin N; Gardner, Frances

2014-12-01

Children from low-income households tend to exhibit higher levels of conduct problems and emotional problems, yet the pathways linking economic disadvantage to children's behavioral functioning are not well understood. This study uses data from the Early Steps Multisite (ESM) project (N = 731) to investigate associations between family income in early childhood and children's conduct problems and emotional problems in middle childhood. The study explores whether the associations from income to child conduct problems and emotional problems operate through maternal depressive symptoms and 3 family risk factors in early childhood-harsh parenting, parenting hassles, and chaos in the home environment. Results of a sequential mediation model revealed significant indirect effects of family income on children's conduct problems operating through maternal depressive symptoms and parenting hassles and indirect effects of family income on children's emotional problems operating through maternal depressive symptoms, chaos in the home environment, and parenting hassles. Implications of these findings for understanding processes through which income influences child functioning are discussed.

Ultrahigh Temperature Capacitive Pressure Sensor

NASA Technical Reports Server (NTRS)

Harsh, Kevin

2014-01-01

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

Autonomous micro and nano sensors for upstream oil and gas

NASA Astrophysics Data System (ADS)

Chapman, David; Trybula, Walt

2015-06-01

This paper describes the development of autonomous electronic micro and nanoscale sensor systems for very harsh downhole oilfield conditions and provides an overview of the operational requirements necessary to survive and make direct measurements of subsurface conditions. One of several significant developmental challenges is selecting appropriate technologies that are simultaneously miniaturize-able, integrate-able, harsh environment capable, and economically viable. The Advanced Energy Consortium (AEC) is employing a platform approach to developing and testing multi-chip, millimeter and micron-scale systems in a package at elevated temperature and pressure in API brine and oil analogs, with the future goal of miniaturized systems that enable the collection of previously unattainable data. The ultimate goal is to develop subsurface nanosensor systems that can be injected into oil and gas well bores, to gather and record data, providing an unparalleled level of direct reservoir characterization. This paper provides a status update on the research efforts and developmental successes at the AEC.

Carbon Fiber Composites

NASA Technical Reports Server (NTRS)

1997-01-01

HyComp(R), Inc. development a line of high temperature carbon fiber composite products to solve wear problems in the harsh environment of steel and aluminum mills. WearComp(R), self-lubricating composite wear liners and bushings, combines carbon graphite fibers with a polyimide binder. The binder, in conjunction with the fibers, provides the slippery surface, one that demands no lubrication, yet wears at a very slow rate. WearComp(R) typically lasts six to ten times longer than aluminum bronze. Unlike bronze, WearComp polishes the same surface and imparts a self-lube film for years of service. It is designed for continuous operation at temperatures of 550 degrees Fahrenheit and can operate under high compressive loads.

Cave Pearl Data Logger: A Flexible Arduino-Based Logging Platform for Long-Term Monitoring in Harsh Environments.

PubMed

Beddows, Patricia A; Mallon, Edward K

2018-02-09

A low-cost data logging platform is presented that provides long-term operation in remote or submerged environments. Three premade "breakout boards" from the open-source Arduino ecosystem are assembled into the core of the data logger. Power optimization techniques are presented which extend the operational life of this module-based design to >1 year on three alkaline AA batteries. Robust underwater housings are constructed for these loggers using PVC fittings. Both the logging platform and the enclosures, are easy to build and modify without specialized tools or a significant background in electronics. This combination turns the Cave Pearl data logger into a generalized prototyping system and this design flexibility is demonstrated with two field studies recording drip rates in a cave and water flow in a flooded cave system. This paper describes a complete DIY solution, suitable for a wide range of challenging deployment conditions.

Cave Pearl Data Logger: A Flexible Arduino-Based Logging Platform for Long-Term Monitoring in Harsh Environments

PubMed Central

Mallon, Edward K.

2018-01-01

A low-cost data logging platform is presented that provides long-term operation in remote or submerged environments. Three premade “breakout boards” from the open-source Arduino ecosystem are assembled into the core of the data logger. Power optimization techniques are presented which extend the operational life of this module-based design to >1 year on three alkaline AA batteries. Robust underwater housings are constructed for these loggers using PVC fittings. Both the logging platform and the enclosures, are easy to build and modify without specialized tools or a significant background in electronics. This combination turns the Cave Pearl data logger into a generalized prototyping system and this design flexibility is demonstrated with two field studies recording drip rates in a cave and water flow in a flooded cave system. This paper describes a complete DIY solution, suitable for a wide range of challenging deployment conditions. PMID:29425185

A reliable data collection/control system

NASA Technical Reports Server (NTRS)

Maughan, Thom

1988-01-01

The Cal Poly Space Project requires a data collection/control system which must be able to reliably record temperature, pressure and vibration data. It must also schedule the 16 electroplating and 2 immiscible alloy experiments so as to optimize use of the batteries, maintain a safe package temperature profile, and run the experiment during conditions of microgravity (and minimum vibration). This system must operate unattended in the harsh environment of space and consume very little power due to limited battery supply. The design of a system which meets these requirements is addressed.

Ruggedized downhole tool for real-time measurements and uses thereof

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

Hess, Ryan Falcone; Lindblom, Scott C.; Yelton, William G.

The present invention relates to ruggedized downhole tools and sensors, as well as uses thereof. In particular, these tools can operate under extreme conditions and, therefore, allow for real-time measurements in geothermal reservoirs or other potentially harsh environments. One exemplary sensor includes a ruggedized ion selective electrode (ISE) for detecting tracer concentrations in real-time. In one embodiment, the ISE includes a solid, non-conductive potting material and an ion selective material, which are disposed in a temperature-resistant electrode body. Other electrode configurations, tools, and methods are also described.

Aerogel: Tile Composites Toughen a Brittle Superinsulation

NASA Technical Reports Server (NTRS)

White, Susan; Rasky, Daniel; Arnold, James O. (Technical Monitor)

1998-01-01

Pure aerogels, though familiar in the laboratory for decades as exotic lightweight insulators with unusual physical properties, have had limited industrial applications due to their low strength and high brittleness. Composites formed of aerogels and the ceramic fiber matrices like those used as space shuttle tiles bypass the fragility of pure aerogels and can enhance the performance of space shuttle tiles in their harsh operating environment. Using a layer of aerogel embedded in a tile may open up a wide range of applications where thermal insulation, gas convection control and mechanical strength matter.

Aerogel: Tile Composites Toughen a Brittle Superinsulation

NASA Technical Reports Server (NTRS)

White, Susan; Rasky, Daniel; Arnold, James O. (Technical Monitor)

1998-01-01

Pure aerogels, though familiar in the laboratory for decades as exotic lightweight insulators with unusual physical properties, have had limited industrial applications due to their low strength and high brittleness. Composites formed of aerogels and the ceramic fiber matrices used as space shuttle tiles bypass the fragility of pure aerogels and can enhance the performance of space shuttle tiles in their harsh operating environment. Using a layer of aerogel embedded in a tile may open up a wide range of applications where thermal insulation, gas convection control and mechanical strength matter.

Packaging Technology Designed, Fabricated, and Assembled for High-Temperature SiC Microsystems

NASA Technical Reports Server (NTRS)

Chen, Liang-Yu

2003-01-01

A series of ceramic substrates and thick-film metalization-based prototype microsystem packages designed for silicon carbide (SiC) high-temperature microsystems have been developed for operation in 500 C harsh environments. These prototype packages were designed, fabricated, and assembled at the NASA Glenn Research Center. Both the electrical interconnection system and the die-attach scheme for this packaging system have been tested extensively at high temperatures. Printed circuit boards used to interconnect these chip-level packages and passive components also are being fabricated and tested. NASA space and aeronautical missions need harsh-environment, especially high-temperature, operable microsystems for probing the inner solar planets and for in situ monitoring and control of next-generation aeronautical engines. Various SiC high-temperature-operable microelectromechanical system (MEMS) sensors, actuators, and electronics have been demonstrated at temperatures as high as 600 C, but most of these devices were demonstrated only in the laboratory environment partially because systematic packaging technology for supporting these devices at temperatures of 500 C and beyond was not available. Thus, the development of a systematic high-temperature packaging technology is essential for both in situ testing and the commercialization of high-temperature SiC MEMS. Researchers at Glenn developed new prototype packages for high-temperature microsystems using ceramic substrates (aluminum nitride and 96- and 90-wt% aluminum oxides) and gold (Au) thick-film metalization. Packaging components, which include a thick-film metalization-based wirebond interconnection system and a low-electrical-resistance SiC die-attachment scheme, have been tested at temperatures up to 500 C. The interconnection system composed of Au thick-film printed wire and 1-mil Au wire bond was tested in 500 C oxidizing air with and without 50-mA direct current for over 5000 hr. The Au thick-film metalization-based wirebond electrical interconnection system was also tested in an extremely dynamic thermal environment to assess thermal reliability. The I-V curve1 of a SiC high-temperature diode was measured in oxidizing air at 500 C for 1000 hr to electrically test the Au thick-film material-based die-attach assembly.

Scanned-wavelength diode laser sensors for harsh environments

NASA Astrophysics Data System (ADS)

Jeffries, Jay B.; Sanders, Scott T.; Zhou, Xin; Ma, Lin; Mattison, Daniel W.; Hanson, Ronald K.

2002-09-01

Diode laser absorption offers the possibility of high-speed, robust, and rugged sensors for a wide variety of practical applications. Pressure broadening complicates absorption measurements of gas temperature and species concentrations in high-pressure, high-temperature practical environments. More agile wavelength scanning can enable measurements of temperature and species concentrations in flames and engines as demonstrated by example measurements using wavelength scanning of a single DFB in laboratory flames or a vertical cavity surface emitting laser (VCSEL) in a pulse detonation engine environment. Although the blending of multiple transitions by pressure broadening complicates the atmospheric pressure spectrum of C2H4 fuel, a scanned wavelength strategy enables quantitative measurement of fuel/oxidizer stoichiometry. Wavelength-agile scanning techniques enable high-speed measurements in these harsh environments.

Head-mounted display systems and the special operations soldier

NASA Astrophysics Data System (ADS)

Loyd, Rodney B.

1998-08-01

In 1997, the Boeing Company, working with DARPA under the Smart Modules program and the US Army Soldier Systems Command, embarked on an advanced research and development program to develop a wearable computer system tailored for use with soldiers of the US Special Operations Command. The 'special operations combat management system' is a rugged advanced wearable tactical computer, designed to provide the special operations soldier with enhanced situation awareness and battlefield information capabilities. Many issues must be considered during the design of wearable computers for a combat soldier, including the system weight, placement on the body with respect to other equipment, user interfaces and display system characteristics. During the initial feasibility study for the system, the operational environment was examined and potential users were interviewed to establish the proper display solution for the system. Many display system requirements resulted, such as head or helmet mounting, Night Vision Goggle compatibility, minimal visible light emissions, environmental performance and even the need for handheld or other 'off the head' type display systems. This paper will address these issues and other end user requirements for display systems for applications in the harsh and demanding environment of the Special Operations soldier.

Testing and evaluation for astronaut extravehicular activity (EVA) operability.

PubMed

Shields, N; King, L C

1998-09-01

Because it is the human component that defines space mission success, careful planning is required to ensure that hardware can be operated and maintained by crews on-orbit. Several methods exist to allow researchers and designers to better predict how hardware designs will behave under the harsh environment of low Earth orbit, and whether designs incorporate the necessary features for Extra Vehicular Activity (EVA) operability. Testing under conditions of simulated microgravity can occur during the design concept phase when verifying design operability, during mission training, or concurrently with on-orbit mission operations. The bulk of testing is focused on normal operations, but also includes evaluation of credible mission contingencies or "what would happen if" planning. The astronauts and cosmonauts who fly these space missions are well prepared and trained to survive and be productive in Earth's orbit. The engineers, designers, and training crews involved in space missions subject themselves to Earth based simulation techniques that also expose them to extreme environments. Aircraft falling ten thousand feet, alternating g-loads, underwater testing at 45 foot depth, enclosure in a vacuum chamber and subject to thermal extremes, each carries with it inherent risks to the humans preparing for space missions.

Vulnerability of CMOS image sensors in Megajoule Class Laser harsh environment.

PubMed

Goiffon, V; Girard, S; Chabane, A; Paillet, P; Magnan, P; Cervantes, P; Martin-Gonthier, P; Baggio, J; Estribeau, M; Bourgade, J-L; Darbon, S; Rousseau, A; Glebov, V Yu; Pien, G; Sangster, T C

2012-08-27

CMOS image sensors (CIS) are promising candidates as part of optical imagers for the plasma diagnostics devoted to the study of fusion by inertial confinement. However, the harsh radiative environment of Megajoule Class Lasers threatens the performances of these optical sensors. In this paper, the vulnerability of CIS to the transient and mixed pulsed radiation environment associated with such facilities is investigated during an experiment at the OMEGA facility at the Laboratory for Laser Energetics (LLE), Rochester, NY, USA. The transient and permanent effects of the 14 MeV neutron pulse on CIS are presented. The behavior of the tested CIS shows that active pixel sensors (APS) exhibit a better hardness to this harsh environment than a CCD. A first order extrapolation of the reported results to the higher level of radiation expected for Megajoule Class Laser facilities (Laser Megajoule in France or National Ignition Facility in the USA) shows that temporarily saturated pixels due to transient neutron-induced single event effects will be the major issue for the development of radiation-tolerant plasma diagnostic instruments whereas the permanent degradation of the CIS related to displacement damage or total ionizing dose effects could be reduced by applying well known mitigation techniques.

Design-for-reliability (DfR) of aerospace electronics: Attributes and challenges

NASA Astrophysics Data System (ADS)

Bensoussan, A.; Suhir, E.

The next generation of multi-beam satellite systems that would be able to provide effective interactive communication services will have to operate within a highly flexible architecture. One option to develop such flexibility is to employ microwaves and/or optoelectronic components and to make them reliable. The use of optoelectronic devices, equipments and systems will result indeed in significant improvement in the state-of-the-art only provided that the new designs will suggest a novel and effective architecture that will combine the merits of good functional performance, satisfactory mechanical (structural) reliability and high cost effectiveness. The obvious challenge is the ability to design and fabricate equipment based on EEE components that would be able to successfully withstand harsh space environments for the entire duration of the mission. It is imperative that the major players in the space industry, such as manufacturers, industrial users, and space agencies, understand the importance and the limits of the achievable quality and reliability of optoelectronic devices operated in harsh environments. It is equally imperative that the physics of possible failures is well understood and, if necessary, minimized, and that adequate Quality Standards are developed and employed. The space community has to identify and to develop the strategic approach for validating optoelectronic products. This should be done with consideration of numerous intrinsic and extrinsic requirements for the systems' performance. When considering a particular next generation optoelectronic space system, the space community needs to address the following major issues: proof of concept for this system, proof of reliability and proof of performance. This should be done with taking into account the specifics of the anticipated application. High operational reliability cannot be left to the prognostics and health monitoring/management (PHM) effort and stage, no matter how important and - ffective such an effort might be. Reliability should be pursued at all the stages of the equipment lifetime: design, product development, manufacturing, burn-in testing and, of course, subsequent PHM after the space apparatus is launched and operated.

Toward controlling perturbations in robotic sensor networks

NASA Astrophysics Data System (ADS)

Banerjee, Ashis G.; Majumder, Saikat R.

2014-06-01

Robotic sensor networks (RSNs), which consist of networks of sensors placed on mobile robots, are being increasingly used for environment monitoring applications. In particular, a lot of work has been done on simultaneous localization and mapping of the robots, and optimal sensor placement for environment state estimation1. The deployment of RSNs, however, remains challenging in harsh environments where the RSNs have to deal with significant perturbations in the forms of wind gusts, turbulent water flows, sand storms, or blizzards that disrupt inter-robot communication and individual robot stability. Hence, there is a need to be able to control such perturbations and bring the networks to desirable states with stable nodes (robots) and minimal operational performance (environment sensing). Recent work has demonstrated the feasibility of controlling the non-linear dynamics in other communication networks like emergency management systems and power grids by introducing compensatory perturbations to restore network stability and operation2. In this paper, we develop a computational framework to investigate the usefulness of this approach for RSNs in marine environments. Preliminary analysis shows promising performance and identifies bounds on the original perturbations within which it is possible to control the networks.

Remote driven and read MEMS sensors for harsh environments.

PubMed

Knobloch, Aaron J; Ahmad, Faisal R; Sexton, Dan W; Vernooy, David W

2013-10-21

The utilization of high accuracy sensors in harsh environments has been limited by the temperature constraints of the control electronics that must be co-located with the sensor. Several methods of remote interrogation for resonant sensors are presented in this paper which would allow these sensors to be extended to harsh environments. This work in particular demonstrates for the first time the ability to acoustically drive a silicon comb drive resonator into resonance and electromagnetically couple to the resonator to read its frequency. The performance of this system was studied as a function of standoff distance demonstrating the ability to excite and read the device from 22 cm when limited to drive powers of 30 mW. A feedback architecture was implemented that allowed the resonator to be driven into resonance from broadband noise and a standoff distance of 15 cm was demonstrated. It is emphasized that no junction-based electronic device was required to be co-located with the resonator, opening the door for the use of silicon-based, high accuracy MEMS devices in high temperature wireless applications.

An Investigation into Soft Error Detection Efficiency at Operating System Level

PubMed Central

Taheri, Hassan

2014-01-01

Electronic equipment operating in harsh environments such as space is subjected to a range of threats. The most important of these is radiation that gives rise to permanent and transient errors on microelectronic components. The occurrence rate of transient errors is significantly more than permanent errors. The transient errors, or soft errors, emerge in two formats: control flow errors (CFEs) and data errors. Valuable research results have already appeared in literature at hardware and software levels for their alleviation. However, there is the basic assumption behind these works that the operating system is reliable and the focus is on other system levels. In this paper, we investigate the effects of soft errors on the operating system components and compare their vulnerability with that of application level components. Results show that soft errors in operating system components affect both operating system and application level components. Therefore, by providing endurance to operating system level components against soft errors, both operating system and application level components gain tolerance. PMID:24574894

An investigation into soft error detection efficiency at operating system level.

PubMed

Asghari, Seyyed Amir; Kaynak, Okyay; Taheri, Hassan

2014-01-01

Electronic equipment operating in harsh environments such as space is subjected to a range of threats. The most important of these is radiation that gives rise to permanent and transient errors on microelectronic components. The occurrence rate of transient errors is significantly more than permanent errors. The transient errors, or soft errors, emerge in two formats: control flow errors (CFEs) and data errors. Valuable research results have already appeared in literature at hardware and software levels for their alleviation. However, there is the basic assumption behind these works that the operating system is reliable and the focus is on other system levels. In this paper, we investigate the effects of soft errors on the operating system components and compare their vulnerability with that of application level components. Results show that soft errors in operating system components affect both operating system and application level components. Therefore, by providing endurance to operating system level components against soft errors, both operating system and application level components gain tolerance.

Predictors of Harsh Parenting Practices in Parents of Children with Disabilities

ERIC Educational Resources Information Center

Norlin, David; Axberg, Ulf; Broberg, Malin

2014-01-01

International research indicates that children with disabilities are more exposed to negative parenting than their non-disabled peers. The mechanisms behind this increased risk are likely operating at the levels of the individual child, the family and the broader social context. The present study investigated harsh parenting practices using…

Impact of Total Ionizing Dose Radiation Testing and Long-Term Thermal Cycling on the Operation of CMF20120D Silicon Carbide Power MOSFET

NASA Technical Reports Server (NTRS)

Patterson, Richard L.; Scheidegger, Robert J.; Lauenstein, Jean-Marie; Casey, Megan; Scheick, Leif; Hammoud, Ahmad

2013-01-01

Power systems designed for use in NASA space missions are required to work reliably under harsh conditions including radiation, thermal cycling, and extreme temperature exposures. Silicon carbide devices show great promise for use in future power electronics systems, but information pertaining to performance of the devices in the space environment is very scarce. A silicon carbide N-channel enhancement-mode power MOSFET called the CMF20120 is of interest for use in space environments. Samples of the device were exposed to radiation followed by long-term thermal cycling to address their reliability for use in space applications. The results of the experimental work are presentd and discussed.

Radiation and Thermal Cycling Effects on EPC1001 Gallium Nitride Power Transistors

NASA Technical Reports Server (NTRS)

Patterson, Richard L.; Scheick, Leif Z.; Lauenstein, Jean M.; Casey, Megan C.; Hammoud, Ahmad

2012-01-01

Electronics designed for use in NASA space missions are required to work efficiently and reliably under harsh environment conditions. These include radiation, extreme temperatures, and thermal cycling, to name a few. Information pertaining to performance of electronic parts and systems under hostile environments is very scarce, especially for new devices. Such data is very critical so that proper design is implemented in order to ensure mission success and to mitigate risks associated with exposure of on-board systems to the operational environment. In this work, newly-developed enhancement-mode field effect transistors (FET) based on gallium nitride (GaN) technology were exposed to various particles of ionizing radiation and to long-term thermal cycling over a wide temperature range. Data obtained on control (un-irradiated) and irradiated samples of these power transistors are presented and the results are discussed.

Thin film diamond temperature sensor array for harsh aerospace environment

NASA Technical Reports Server (NTRS)

Aslam, M.; Masood, A.; Fredricks, R. J.; Tamor, M. A.

1992-01-01

The feasibility of using polycrystalline CVD diamond films as temperature sensors in harsh aerospace environment associated with hypersonic flights was tested using patterned diamond resistors, fabricated on flat or curved oxidized Si surfaces, as temperature sensors at temperatures between 20 and 1000 C. In this temperature range, the measured resistance was found to vary over 3 orders of magnitude and the temperature coefficient of resistance to change from 0.017/K to 0.003/K. After an annealing treatment, the resistance change was reproducible within 1 percent on the entire temperature range for short measuring times.

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

Dowla, F

Long-range, ultra-wideband (UWB), passive radio frequency (RF) tags are key components in Radio Frequency IDentification (RFID) system that will revolutionize inventory control and tracking applications. Unlike conventional, battery-operated (active) RFID tags, LLNL's small UWB tags, called 'UTag', operate at long range (up to 20 meters) in harsh, cluttered environments. Because they are battery-less (that is, passive), they have practically infinite lifetimes without human intervention, and they are lower in cost to manufacture and maintain than active RFID tags. These robust, energy-efficient passive tags are remotely powered by UWB radio signals, which are much more difficult to detect, intercept, and jammore » than conventional narrowband frequencies. The features of long range, battery-less, and low cost give UTag significant advantage over other existing RFID tags.« less

The Micro Imaging and Dust Analysis System - New Possibilities for Space Sciences

NASA Astrophysics Data System (ADS)

Schmied, R.; Torkar, K..; Jeszenszky, H.; Romstedt, J.; Mannel, T.; Bentley, M. S.

2015-10-01

The Rosetta mission addresses a range of fundamental questions in Solar System and cometary science and the MIDAS instrument on-board the orbiter is one of the dust analysis systems. While GIADA analyses the dust flux and spatial distribution as a function of time and space and COSIMA investigates the elemental composition of cometary grains, MIDAS is a unique high resolution Atomic Force Microscope (AFM) combined with a dust collection and handling system designed to reveal the three-dimensional topographical structure of nanoand micrometer sized dust particles [1]. In this work we concentrate on the instrumental functionality and limitations coming from the constcution and operation dealing with an AFM fabricated nearly 20 years ago and operating in a harsh environment.

Patterns of lake occupancy by fish indicate different adaptations to life in a harsh Arctic environment

USGS Publications Warehouse

Haynes, Trevor B.; Rosenberger, Amanda E.; Lindberg, Mark S.; Whitman, Matthew; Schmutz, Joel A.

2014-01-01

Based on these patterns, we propose an overall model of primary controls on the distribution of fish on the Arctic Coastal Plain of Alaska. Harsh conditions, including lake freezing, limit occupancy in winter through extinction events while lake occupancy in spring and summer is driven by directional migration (large-bodied species) and undirected dispersal (small-bodied species).

Sustainable energy at the 100 W level for scientific sites on the Antarctic Plateau: Lessons learned from the Polar Experiment Network for Geospace Upper atmosphere Investigations-Automatic Geophysical Observatory project

NASA Astrophysics Data System (ADS)

Melville, R.; Stillinger, A.; Gerrard, A.; Weatherwax, A.

2014-04-01

The need to provide power to unmanned instrumentation over the course of an entire year on the Antarctic plateau presents a large number of engineering and logistical challenges. Designs formulated in ideal laboratory environments often fail in the Antarctic due to the harsh operating conditions, and field experience is necessary to achieve year-round operation in the 100 W power range. In this paper we present our current power design for the Automatic Geophysical Observatories; a design based on over two decades of experience on the ice and allows for relatively continuous operation at the aforementioned power level. We also discuss our various implementation methods, both failures and successes, in an effort assist other unmanned deployments on the ice.

Sustainable energy at the 100 W level for scientific sites on the Antarctic Plateau: lessons learned from the Polar Experiment Network for Geospace Upper atmosphere Investigations-Automatic Geophysical Observatory project.

PubMed

Melville, R; Stillinger, A; Gerrard, A; Weatherwax, A

2014-04-01

The need to provide power to unmanned instrumentation over the course of an entire year on the Antarctic plateau presents a large number of engineering and logistical challenges. Designs formulated in ideal laboratory environments often fail in the Antarctic due to the harsh operating conditions, and field experience is necessary to achieve year-round operation in the 100 W power range. In this paper we present our current power design for the Automatic Geophysical Observatories; a design based on over two decades of experience on the ice and allows for relatively continuous operation at the aforementioned power level. We also discuss our various implementation methods, both failures and successes, in an effort assist other unmanned deployments on the ice.

Low Temperature Characterization of Ceramic and Film Power Capacitors

NASA Technical Reports Server (NTRS)

Hammoud, Ahmad; Overton, Eric

1996-01-01

Among the key requirements for advanced electronic systems is the ability to withstand harsh environments while maintaining reliable and efficient operation. Exposures to low temperature as well as high temperature constitute such stresses. Applications where low temperatures are encountered include deep space missions, medical imaging equipment, and cryogenic instrumentation. Efforts were taken to design and develop power capacitors capable of wide temperature operation. In this work, ceramic and film power capacitors were developed and characterized as a function of temperature from 20 C to -185 C in terms of their dielectric properties. These properties included capacitance stability and dielectric loss in the frequency range of 50 Hz to 100 kHz. DC leakage current measurements were also performed on the capacitors. The manuscript presents the results that indicate good operational characteristic behavior and stability of the components tested at low temperatures.

An Overview of Wide Bandgap Silicon Carbide Sensors and Electronics Development at NASA Glenn Research Center

NASA Technical Reports Server (NTRS)

Hunter, Gary W.; Neudeck, Philip G.; Beheim, Glenn M.; Okojie, Robert S.; Chen, Liangyu; Spry, D.; Trunek, A.

2007-01-01

A brief overview is presented of the sensors and electronics development work ongoing at NASA Glenn Research Center which is intended to meet the needs of future aerospace applications. Three major technology areas are discussed: 1) high temperature SiC electronics, 2) SiC gas sensor technology development, and 3) packaging of harsh environment devices. Highlights of this work include world-record operation of SiC electronic devices including 500?C JFET transistor operation with excellent properties, atomically flat SiC gas sensors integrated with an on-chip temperature detector/heater, and operation of a packaged AC amplifier. A description of the state-of-the-art is given for each topic. It is concluded that significant progress has been made and that given recent advancements the development of high temperature smart sensors is envisioned.

An embedded laser marking controller based on ARM and FPGA processors.

PubMed

Dongyun, Wang; Xinpiao, Ye

2014-01-01

Laser marking is an important branch of the laser information processing technology. The existing laser marking machine based on PC and WINDOWS operating system, are large and inconvenient to move. Still, it cannot work outdoors or in other harsh environments. In order to compensate for the above mentioned disadvantages, this paper proposed an embedded laser marking controller based on ARM and FPGA processors. Based on the principle of laser galvanometer scanning marking, the hardware and software were designed for the application. Experiments showed that this new embedded laser marking controller controls the galvanometers synchronously and could achieve precise marking.

Research and development of optical measurement techniques for aerospace propulsion research: A NASA Lewis Research Center perspective

NASA Technical Reports Server (NTRS)

Lesco, Daniel J.

1991-01-01

The applied research effort required to develop new nonintrusive measurement techniques capable of obtaining the data required by aerospace propulsion researchers and of operating in the harsh environments encountered in research and test facilities is discussed and illustrated through several ongoing projects at NASA's Lewis Research Center. Factors including length of development time, funding levels, and collaborative support from fluid-thermal researchers are cited. Progress in developing new instrumentation via a multi-path approach, including NASA research, grant, and government-sponsored research through mechanisms like the Small Business Innovative Research program, is also described.

NASA-JPL overview, space technology and relevance to medicine (Conference Presentation)

NASA Astrophysics Data System (ADS)

van Zyl, Jakob

2017-05-01

There is special synergy between NASA space instruments and medical devices, especially those that may be implanted in the human body. For example, in both cases instruments have to be small, typically have to consume little power and often have to operate in harsh environments. JPL has a long history in using this synergy to leverage from the technology developed for space missions for application in medical fields. In this talk, we discuss the general overlap of technological requirements in the medical field and space science. We will highlight some examples where JPL instrumentation and engineering has been transferred successfully.

Analysis and improvement of gas turbine blade temperature measurement error

NASA Astrophysics Data System (ADS)

Gao, Shan; Wang, Lixin; Feng, Chi; Daniel, Ketui

2015-10-01

Gas turbine blade components are easily damaged; they also operate in harsh high-temperature, high-pressure environments over extended durations. Therefore, ensuring that the blade temperature remains within the design limits is very important. In this study, measurement errors in turbine blade temperatures were analyzed, taking into account detector lens contamination, the reflection of environmental energy from the target surface, the effects of the combustion gas, and the emissivity of the blade surface. In this paper, each of the above sources of measurement error is discussed, and an iterative computing method for calculating blade temperature is proposed.

Tapered slot antenna design for vehicular GPR applications

NASA Astrophysics Data System (ADS)

Bıçak, Emrullah; Yeǧin, Korkut; Nazlı, Hakki; Daǧ, Mahmut

2014-05-01

Vehicular applications of UWB GPR demand multiple GPR sensors operating in a harsh environment. One of the key elements of in the sensor is its UWB antenna which has minimal inter-element coupling, low group delay, high directivity and less prone to environmental conditions. Tapered slot antennas (TSA's) provide good impedance match, but they need to be modified for above specifications. Parasitic slot loaded TSA with balanced feed is proposed and a multi-channel antenna array structure is formed. Structural parameters are numerically analyzed and a prototype is built. Measurements show good performance for UWB GPR applications.

Reconfigurable Computing Concepts for Space Missions: Universal Modular Spares

NASA Technical Reports Server (NTRS)

Patrick, M. Clinton

2007-01-01

Computing hardware for control, data collection, and other purposes will prove many times over crucial resources in NASA's upcoming space missions. Ability to provide these resources within mission payload requirements, with the hardiness to operate for extended periods under potentially harsh conditions in off-World environments, is daunting enough without considering the possibility of doing so with conventional electronics. This paper examines some ideas and options, and proposes some initial approaches, for logical design of reconfigurable computing resources offering true modularity, universal compatibility, and unprecedented flexibility to service all forms and needs of mission infrastructure.

Current Issues in Human Spacecraft Thermal Control Technology

NASA Technical Reports Server (NTRS)

Ungar, Eugene K.

2008-01-01

Efficient thermal management of Earth-orbiting human spacecraft, lunar transit spacecraft and landers, as well as a lunar habitat will require advanced thermal technology. These future spacecraft will require more sophisticated thermal control systems that can dissipate or reject greater heat loads at higher input heat fluxes while using fewer of the limited spacecraft mass, volume and power resources. The thermal control designs also must accommodate the harsh environments associated with these missions including dust and high sink temperatures. The lunar environment presents several challenges to the design and operation of active thermal control systems. During the Apollo program, landings were located and timed to occur at lunar twilight, resulting in a benign thermal environment. The long duration polar lunar bases that are foreseen in 15 years will see extremely cold thermal environments. Long sojourns remote from low-Earth orbit will require lightweight, but robust and reliable systems. Innovative thermal management components and systems are needed to accomplish the rejection of heat from lunar bases. Advances are required in the general areas of radiators, thermal control loops and equipment. Radiators on the Moon's poles must operate and survive in very cold environments. Also, the dusty environment of an active lunar base may require dust mitigation and removal techniques to maintain radiator performance over the long term.

Operational environments for electrical power wiring on NASA space systems

NASA Technical Reports Server (NTRS)

Stavnes, Mark W.; Hammoud, Ahmad N.; Bercaw, Robert W.

1994-01-01

Electrical wiring systems are used extensively on NASA space systems for power management and distribution, control and command, and data transmission. The reliability of these systems when exposed to the harsh environments of space is very critical to mission success and crew safety. Failures have been reported both on the ground and in flight due to arc tracking in the wiring harnesses, made possible by insulation degradation. This report was written as part of a NASA Office of Safety and Mission Assurance (Code Q) program to identify and characterize wiring systems in terms of their potential use in aerospace vehicles. The goal of the program is to provide the information and guidance needed to develop and qualify reliable, safe, lightweight wiring systems, which are resistant to arc tracking and suitable for use in space power applications. This report identifies the environments in which NASA spacecraft will operate, and determines the specific NASA testing requirements. A summary of related test programs is also given in this report. This data will be valuable to spacecraft designers in determining the best wiring constructions for the various NASA applications.

Development of Electronics for Low-Temperature Space Missions

NASA Technical Reports Server (NTRS)

Patterson, Richard L.; Hammoud, Ahmad; Dickman, John E.; Gerber, Scott S.; Overton, Eric

2001-01-01

Electronic systems that are capable of operating at cryogenic temperatures will be needed for many future NASA space missions, including deep space probes and spacecraft for planetary surface exploration. In addition to being able to survive the harsh deep space environment, low-temperature electronics would help improve circuit performance, increase system efficiency, and reduce payload development and launch costs. Terrestrial applications where components and systems must operate in low-temperature environments include cryogenic instrumentation, superconducting magnetic energy storage, magnetic levitation transportation systems, and arctic exploration. An ongoing research and development project for the design, fabrication, and characterization of low-temperature electronics and supporting technologies at NASA Glenn Research Center focuses on efficient power systems capable of surviving in and exploiting the advantages of low-temperature environments. Supporting technologies include dielectric and insulating materials, semiconductor devices, passive power components, optoelectronic devices, and packaging and integration of the developed components into prototype flight hardware. An overview of the project is presented, including a description of the test facilities, a discussion of selected data from component testing, and a presentation of ongoing research activities being performed in collaboration with various organizations.

Performance of the Micropower Voltage Reference ADR3430 Under Extreme Temperatures

NASA Technical Reports Server (NTRS)

Patterson, Richard L.; Hammoud, Ahmad

2011-01-01

Electronic systems designed for use in space exploration systems are expected to be exposed to harsh temperatures. For example, operation at cryogenic temperatures is anticipated in space missions such as polar craters of the moon (-223 C), James Webb Space Telescope (-236 C), Mars (-140 C), Europa (-223 C), Titan (-178 C), and other deep space probes away from the sun. Similarly, rovers and landers on the lunar surface, and deep space probes intended for the exploration of Venus are expected to encounter high temperature extremes. Electronics capable of operation under extreme temperatures would not only meet the requirements of future spacebased systems, but would also contribute to enhancing efficiency and improving reliability of these systems through the elimination of the thermal control elements that present electronics need for proper operation under the harsh environment of space. In this work, the performance of a micropower, high accuracy voltage reference was evaluated over a wide temperature range. The Analog Devices ADR3430 chip uses a patented voltage reference architecture to achieve high accuracy, low temperature coefficient, and low noise in a CMOS process [1]. The device combines two voltages of opposite temperature coefficients to create an output voltage that is almost independent of ambient temperature. It is rated for the industrial temperature range of -40 C to +125 C, and is ideal for use in low power precision data acquisition systems and in battery-powered devices. Table 1 shows some of the manufacturer s device specifications.

Spontaneous growth of polarizing refractory metal ‘nano-fins’

NASA Astrophysics Data System (ADS)

Tai, M. C.; Gentle, A. R.; Arnold, M. D.; Cortie, M. B.

2018-03-01

Traditional polymer polarizers degrade in harsh environments and at high temperatures, reducing the polarization effect. In contrast, polarizers produced with refractory metals have vastly improved thermal stability and resistance to harsh environments but are expensive to fabricate. Here we demonstrate prototype refractory metal wire grid polarizers produced by co-sputtering molybdenum and aluminum under specific conditions. Removal of the aluminum through selective dissolution enables the nanostructure array to transmit light. The polarization spans 500-1100 nm and the extinction ratio significantly increases to >100. Possessing broadband polarization and sufficient extinction ratios, the new polarizing film has potential applications in coatings for sunglasses, windows, pyrometers, scientific instruments, and LCD panels.

Multiplexed absorption tomography with calibration-free wavelength modulation spectroscopy

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

Cai, Weiwei; Kaminski, Clemens F., E-mail: cfk23@cam.ac.uk

2014-04-14

We propose a multiplexed absorption tomography technique, which uses calibration-free wavelength modulation spectroscopy with tunable semiconductor lasers for the simultaneous imaging of temperature and species concentration in harsh combustion environments. Compared with the commonly used direct absorption spectroscopy (DAS) counterpart, the present variant enjoys better signal-to-noise ratios and requires no baseline fitting, a particularly desirable feature for high-pressure applications, where adjacent absorption features overlap and interfere severely. We present proof-of-concept numerical demonstrations of the technique using realistic phantom models of harsh combustion environments and prove that the proposed techniques outperform currently available tomography techniques based on DAS.

Multiple benefits of alloparental care in a fluctuating environment.

PubMed

Guindre-Parker, Sarah; Rubenstein, Dustin R

2018-02-01

Although cooperatively breeding vertebrates occur disproportionately in unpredictable environments, the underlying mechanism shaping this biogeographic pattern remains unclear. Cooperative breeding may buffer against harsh conditions (hard life hypothesis), or additionally allow for sustained breeding under benign conditions (temporal variability hypothesis). To distinguish between the hard life and temporal variability hypotheses, we investigated whether the number of alloparents at a nest increased reproductive success or load-lightening in superb starlings ( Lamprotornis superbus ), and whether these two types of benefits varied in harsh and benign years. We found that mothers experienced both types of benefits consistent with the temporal variability hypothesis, as larger contingents of alloparents increased the number of young fledged while simultaneously allowing mothers to reduce their provisioning rates under both harsh and benign rainfall conditions. By contrast, fathers experienced load-lightening only under benign rainfall conditions, suggesting that cooperative breeding may serve to take advantage of unpredictable benign breeding seasons when they do occur. Cooperative breeding in unpredictable environments may thus promote flexibility in offspring care behaviour, which could mitigate variability in the cost of raising young. Our results highlight the importance of considering how offspring care decisions vary among breeding roles and across fluctuating environmental conditions.

Multiple benefits of alloparental care in a fluctuating environment

PubMed Central

2018-01-01

Although cooperatively breeding vertebrates occur disproportionately in unpredictable environments, the underlying mechanism shaping this biogeographic pattern remains unclear. Cooperative breeding may buffer against harsh conditions (hard life hypothesis), or additionally allow for sustained breeding under benign conditions (temporal variability hypothesis). To distinguish between the hard life and temporal variability hypotheses, we investigated whether the number of alloparents at a nest increased reproductive success or load-lightening in superb starlings (Lamprotornis superbus), and whether these two types of benefits varied in harsh and benign years. We found that mothers experienced both types of benefits consistent with the temporal variability hypothesis, as larger contingents of alloparents increased the number of young fledged while simultaneously allowing mothers to reduce their provisioning rates under both harsh and benign rainfall conditions. By contrast, fathers experienced load-lightening only under benign rainfall conditions, suggesting that cooperative breeding may serve to take advantage of unpredictable benign breeding seasons when they do occur. Cooperative breeding in unpredictable environments may thus promote flexibility in offspring care behaviour, which could mitigate variability in the cost of raising young. Our results highlight the importance of considering how offspring care decisions vary among breeding roles and across fluctuating environmental conditions. PMID:29515910

Self-Powered Wireless Sensors

NASA Technical Reports Server (NTRS)

Dynys, Fred; Sayir, Ali

2008-01-01

NASA's integrated vehicle health management (IVHM) program offers the potential to improve aeronautical safety, reduce cost and improve performance by utilizing networks of wireless sensors. Development of sensor systems for engine hot sections will provide real-time data for prognostics and health management of turbo-engines. Sustainable power to embedded wireless sensors is a key challenge for prolong operation. Harvesting energy from the environment has emerged as a viable technique for power generation. Thermoelectric generators provide a direct conversion of heat energy to electrical energy. Micro-power sources derived from thermoelectric films are desired for applications in harsh thermal environments. Silicon based alloys are being explored for applications in high temperature environments containing oxygen. Chromium based p-type Si/Ge alloys exhibit Seebeck coefficients on the order of 160 micro V/K and low thermal conductance of 2.5 to 5 W/mK. Thermoelectric properties of bulk and thin film silicides will be discussed

Resilient and Corrosion-proof Rolling Element Bearings Made from Ni-ti Alloys for Aerospace Mechanism Applications and the Ultimate Space Technology Development Platform

NASA Technical Reports Server (NTRS)

Dellacorte, Christopher

2014-01-01

The International Space Station provides a unique microgravity laboratory environment for research. The ISS also serves as an effective platform for the development of technologies and engineered solutions related to living and working in space. The space environment also challenges our capabilities related to lubrication and tribology. In this seminar, Dr. DellaCorte will review the basics of space mechanism tribology and the challenges of providing good lubrication and long-life in the harsh space environment. He will also discuss recent tribological challenges associated with the Solar Alpha Rotary Joint (SARJ) bearings and life support hardware that must operate under severe conditions that are literally out of this world. Each tribology challenge is unique and their solutions often result in new technologies that benefit the tribology community everywhere, even back on Earth

Space and Atmospheric Environments

NASA Technical Reports Server (NTRS)

Barth, Janet L.; Day, John H. (Technical Monitor)

2002-01-01

This viewgraph presentation provides information on space environments and the protection of materials and structures from their harsh conditions. Space environments are complex, and the complexity of spacecraft systems is increasing. Design accommodation must be realistic. Environmental problems can be limited at low cost relative to spacecraft cost.

Environmental factors, immune changes and respiratory diseases in troops during military activities.

PubMed

Korzeniewski, Krzysztof; Nitsch-Osuch, Aneta; Chciałowski, Andrzej; Korsak, Jolanta

2013-06-01

Combat operations in contemporary theaters of war, as well as combat training, are carried out in all parts of the world, typically in a harsh environment. Specific environmental conditions, such as heat, cold, high-altitudes, desert climates, as well as chemical and biological pollution of both the atmosphere and soil, together with over-exertion, food restrictions, sleep deprivation, and psychological stress can all result in changes in the immune system and the occurrence of associated diseases. Respiratory diseases are one of the most common health problems among military personnel participating in combat training or deployed to operations in areas characterized by difficult climatic and sanitary conditions. They are, therefore, one of the main reasons for military personnel requiring ambulant and hospital treatment. The aim of the study was to discuss the influence of environmental factors and the conditions in which active duty is performed on changes in the immune system and the occurrence of respiratory tract diseases in a military environment. Copyright © 2013 Elsevier B.V. All rights reserved.

Avalanche photo diodes in the observatory environment: lucky imaging at 1-2.5 microns

NASA Astrophysics Data System (ADS)

Vaccarella, A.; Sharp, R.; Ellis, M.; Singh, S.; Bloxham, G.; Bouchez, A.; Conan, R.; Boz, R.; Bundy, D.; Davies, J.; Espeland, B.; Hart, J.; Herrald, N.; Ireland, M.; Jacoby, G.; Nielsen, J.; Vest, C.; Young, P.; Fordham, B.; Zovaro, A.

2016-08-01

The recent availability of large format near-infrared detectors with sub-election readout noise is revolutionizing our approach to wavefront sensing for adaptive optics. However, as with all near-infrared detector technologies, challenges exist in moving from the comfort of the laboratory test-bench into the harsh reality of the observatory environment. As part of the broader adaptive optics program for the GMT, we are developing a near-infrared Lucky Imaging camera for operational deployment at the ANU 2.3 m telescope at Siding Spring Observatory. The system provides an ideal test-bed for the rapidly evolving Selex/SAPHIRA eAPD technology while providing scientific imaging at angular resolution rivalling the Hubble Space Telescope at wavelengths λ = 1.3-2.5 μm.

Intelligent Memory Module Overcomes Harsh Environments

NASA Technical Reports Server (NTRS)

2008-01-01

Solar cells, integrated circuits, and sensors are essential to manned and unmanned space flight and exploration, but such systems are highly susceptible to damage from radiation. Especially problematic, the Van Allen radiation belts encircle Earth in concentric radioactive tori at distances from about 6,300 to 38,000 km, though the inner radiation belt can dip as low as 700 km, posing a severe hazard to craft and humans leaving Earth s atmosphere. To avoid this radiation, the International Space Station and space shuttles orbit at altitudes between 275 and 460 km, below the belts range, and Apollo astronauts skirted the edge of the belts to minimize exposure, passing swiftly through thinner sections of the belts and thereby avoiding significant side effects. This radiation can, however, prove detrimental to improperly protected electronics on satellites that spend the majority of their service life in the harsh environment of the belts. Compact, high-performance electronics that can withstand extreme environmental and radiation stress are thus critical to future space missions. Increasing miniaturization of electronics addresses the need for lighter weight in launch payloads, as launch costs put weight at a premium. Likewise, improved memory technologies have reduced size, cost, mass, power demand, and system complexity, and improved high-bandwidth communication to meet the data volume needs of the next-generation high-resolution sensors. This very miniaturization, however, has exacerbated system susceptibility to radiation, as the charge of ions may meet or exceed that of circuitry, overwhelming the circuit and disrupting operation of a satellite. The Hubble Space Telescope, for example, must turn off its sensors when passing through intense radiation to maintain reliable operation. To address the need for improved data quality, additional capacity for raw and processed data, ever-increasing resolution, and radiation tolerance, NASA spurred the development of the Radiation Tolerant Intelligent Memory Stack (RTIMS).

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

Lall, Pradeep; Zhang, Hao; Davis, J Lynn

The energy efficiency of light-emitting diode (LED) technology compared to incandescent light bulbs has triggered an increased focus on solid state luminaries for a variety of lighting applications. Solid-state lighting (SSL) utilizes LEDs, for illumination through the process of electroluminescence instead of heating a wire filament as seen with traditional lighting. The fundamental differences in the construction of LED and the incandescent lamp results in different failure modes including lumen degradation, chromaticity shift and drift in the correlated color temperature. The use of LED-based products for safety-critical and harsh environment applications necessitates the characterization of the failure mechanisms and modes.more » In this paper, failure mechanisms and color stability has been studied for commercially available vertical structured thin film LED (VLED) under harsh environment conditions with and without the presence of contaminants. The VLED used for the study was mounted on a ceramic starboard in order to connect it to the current source. Contamination sources studied include operation in the vicinity of vulcanized rubber and adhesive epoxies in the presence of temperature and humidity. Performance of the VLEDs has been quantified using the measured luminous flux and color shift of the VLEDs subjected to both thermal and humidity stresses under a forward current bias of 350 mA. Results indicate that contamination can result in pre-mature luminous flux degradation and color shift in LEDs.« less

A custom acoustic emission monitoring system for harsh environments: application to freezing-induced damage in alpine rock-walls

NASA Astrophysics Data System (ADS)

Girard, L.; Beutel, J.; Gruber, S.; Hunziker, J.; Lim, R.; Weber, S.

2012-06-01

We present a custom acoustic emission (AE) monitoring system designed to perform long-term measurements on high-alpine rock-walls. AE monitoring is a common technique for characterizing damage evolution in solid materials. The system is based on a two-channel AE sensor node (AE-node) integrated into a Wireless Sensor Network (WSN) customized for operation in harsh environments. This wireless architecture offers flexibility in the deployment of AE-nodes at any position of the rock-wall that needs to be monitored, within a range of a few hundred meters from a core station connected to the internet. The system achieves near real-time data delivery and allows the user to remotely control the AE detection threshold. In order to protect AE sensors and capture acoustic signals from specific depths of the rock-wall, a special casing was developed. The monitoring system is completed by two probes that measure rock temperature and liquid water content, both probes being also integrated into the WSN. We report a first deployment of the monitoring system on a rock-wall at Jungfraujoch, 3500 m a.s.l., Switzerland. While this first deployment of the monitoring system aims to support fundamental research on processes that damage rock under cold climate, the system could serve a number of other applications, including rock-fall hazard surveillance or structural monitoring of concrete structures.

A custom acoustic emission monitoring system for harsh environments: application to freezing-induced damage in alpine rock walls

NASA Astrophysics Data System (ADS)

Girard, L.; Beutel, J.; Gruber, S.; Hunziker, J.; Lim, R.; Weber, S.

2012-11-01

We present a custom acoustic emission (AE) monitoring system designed to perform long-term measurements on high-alpine rock walls. AE monitoring is a common technique for characterizing damage evolution in solid materials. The system is based on a two-channel AE sensor node (AE-node) integrated into a wireless sensor network (WSN) customized for operation in harsh environments. This wireless architecture offers flexibility in the deployment of AE-nodes at any position of the rock wall that needs to be monitored, within a range of a few hundred meters from a core station connected to the internet. The system achieves near real-time data delivery and allows the user to remotely control the AE detection threshold. In order to protect AE sensors and capture acoustic signals from specific depths of the rock wall, a special casing was developed. The monitoring system is completed by two probes that measure rock temperature and liquid water content, both probes being also integrated into the WSN. We report a first deployment of the monitoring system on a rock wall at Jungfraujoch, 3500 m a.s.l., Switzerland. While this first deployment of the monitoring system aims to support fundamental research on processes that damage rock under cold climate, the system could serve a number of other applications, including rock fall hazard surveillance or structural monitoring of concrete structures.

Gain stabilization control system of the upgraded magnetic proton recoil neutron spectrometer at JET.

PubMed

Sjöstrand, Henrik; Andersson Sundén, E; Conroy, S; Ericsson, G; Gatu Johnson, M; Giacomelli, L; Gorini, G; Hellesen, C; Hjalmarsson, A; Popovichev, S; Ronchi, E; Tardocchi, M; Weiszflog, M

2009-06-01

Burning plasma experiments such as ITER and DEMO require diagnostics capable of withstanding the harsh environment generated by the intense neutron flux and to maintain stable operating conditions for times longer than present day systems. For these reasons, advanced control and monitoring (CM) systems will be necessary for the reliable operation of diagnostics. This paper describes the CM system of the upgraded magnetic proton recoil neutron spectrometer installed at the Joint European Torus focusing in particular on a technique for the stabilization of the gain of the photomultipliers coupled to the neutron detectors. The results presented here show that this technique provides good results over long time scales. The technique is of general interest for all diagnostics that employ scintillators coupled to photomultiplier tubes.

Processing and Characterization of Thousand-Hour 500 C Durable 4H-SiC JFET Integrated Circuits

NASA Technical Reports Server (NTRS)

Spry, David J.; Neudeck, Philip G.; Chen, Liangyu; Lukco, Dorothy; Chang, Carl W.; Beheim, Glenn M.; Krasowski, Michael J.; Prokop, Norman F.

2016-01-01

This work reports fabrication and testing of integrated circuits (ICs) with two levels of interconnect that consistently achieve greater than 1000 hours of stable electrical operation at 500 C in air ambient. These ICs are based on 4H-SiC junction field effect transistor (JFET) technology that integrates hafnium ohmic contacts with TaSi2 interconnects and SiO2 and Si3N4 dielectric layers over 1-m scale vertical topology. Following initial burn-in, important circuit parameters remain stable for more than 1000 hours of 500 C operational testing. These results advance the technology foundation for realizing long-term durable 500 C ICs with increased functional capability for sensing and control combustion engine, planetary, deep-well drilling, and other harsh-environment applications.

Processing and Characterization of Thousand-Hour 500 C Durable 4H-SiC JFET Integrated Circuits

NASA Technical Reports Server (NTRS)

Spry, David J.; Neudeck, Philip G.; Chen, Liang-Yu; Lukco, Dorothy; Chang, Carl W.; Beheim, Glenn M.; Krasowski, Michael J.; Prokop, Norman F.

2016-01-01

This work reports fabrication and testing of integrated circuits (ICs) with two levels of interconnect that consistently achieve greater than 1000 hours of stable electrical operation at 500 C in air ambient. These ICs are based on 4H-SiC junction field effect transistor (JFET) technology that integrates hafnium ohmic contacts with TaSi2 interconnects and SiO2 and Si3N4 dielectric layers over approximately 1-micrometer scale vertical topology. Following initial burn-in, important circuit parameters remain stable for more than 1000 hours of 500 C operational testing. These results advance the technology foundation for realizing long-term durable 500 C ICs with increased functional capability for sensing and control combustion engine, planetary, deep-well drilling, and other harsh-environment applications.

Long Term, Operational Monitoring Of Enhanced Oil Recovery In Harsh Environments With INSAR

NASA Astrophysics Data System (ADS)

Sato, S.; Henschel, M. D.

2012-01-01

Since 2004, MDA GSI has provided ground deformation measurements for an oil field in northern Alberta, Canada using InSAR technology. During this period, the monitoring has reliably shown the slow rise of the oil field due to enhanced oil recovery operations. The InSAR monitoring solution is essentially based on the observation of point and point-like targets in the field. Ground conditions in the area are almost continuously changing (in their reflectivity characteristics) making it difficult to ob- serve coherent patterns from the ground. The extended duration of the oil operations has allowed us to continue InSAR monitoring and transition from RADARSAT-1 to RADARSAT-2. With RADARSAT-2 and the enhancement of the satellite resolution capability has provided more targets of opportunity as identified by a differential coherence method. This poster provides an overview of the long term monitoring of the oil field in northern Alberta, Canada.

Self-assembly of cobalt-centered metal organic framework and multiwalled carbon nanotubes hybrids as a highly active and corrosion-resistant bifunctional oxygen catalyst

NASA Astrophysics Data System (ADS)

Fang, Yiyun; Li, Xinzhe; Li, Feng; Lin, Xiaoqing; Tian, Min; Long, Xuefeng; An, Xingcai; Fu, Yan; Jin, Jun; Ma, Jiantai

2016-09-01

Metal organic frameworks (MOF) derived carbonaceous materials have emerged as promising bifunctional oxygen evolution reaction (OER) and oxygen reduction reaction (ORR) catalysts for electrochemical energy conversion and storage. But previous attempts to overcome the poor electrical conductivity of MOFs hybrids involve a harsh high-template pyrolytic process to in situ form carbon, which suffer from extremely complex operation and inevitable carbon corrosion at high positive potentials when OER is operated. Herein, a self-assembly approach is presented to synthesize a non-precious metal-based, high active and strong durable Co-MOF@CNTs bifunctional catalyst for OER and ORR. CNTs not only improve the transportation of the electrons but also can sustain the harsh oxidative environment of OER without carbon corrosion. Meanwhile, the unique 3D hierarchical structure offers a large surface area and stable anchoring sites for active centers and CNTs, which enables the superior durability of hybrid. Moreover, a synergistic catalysis of Co(II), organic ligands and CNTs will enhance the bifunctional electrocatalytic performance. Impressively, the hybrid exhibits comparable OER and ORR catalytic activity to RuO2 and 20 wt% Pt/C catalysts and superior stability. This facile and versatile strategy to fabricating MOF-based hybrids may be extended to other electrode materials for fuel cell and water splitting applications.

Engineering for Autonomous Seismic Stations at the IRIS PASSCAL Instrument Center

NASA Astrophysics Data System (ADS)

Anderson, K. R.; Carpenter, P.; Beaudoin, B. C.; Parker, T.; Hebert, J.; Childs, D.; Chung, P.; Reusch, A. M.

2015-12-01

The NSF funded Incorporated Research Institutions for Seismology (IRIS) through New Mexico Tech operates the PASSCAL Instrument Center (PIC) in Socorro New Mexico. The engineering effort at the PIC seeks to optimize seismic station operations for all portable experiments, include those in extremely remote and harsh polar environments. Recent advances have resulted in improved station design, allowing improved operational efficiencies, data quality return and reduction in station logistics associated with installation, maintenance and decommissioning of stations. These include: Battery and power system designs. Incorporating primary Lithium Thionyl Chloride (LTC) technology with rechargeable Lithium Iron Phosphate (LiFePO4) batteries allows systems to operate in areas with long-term solar autonomy (high latitudes). Development includes charge controller systems to switch between primary and secondary technologies efficiently. Enclosures: Engineered solutions to efficiently manage waste heat, maintain operational environment and provide light-weight and durable housing for seismic instrumentation. Communications: In collaboration with Xeos Technologies Inc., we deliver Iridium-based SOH/Command and Control telemetry as well as full bandwidth seismic data communications in high latitude environments at low power requirements. Smaller-lighter-instrumentation: Through the GEOICE MRI, we are working with Nanometrics on next generation "all-in-one" seismic systems that can be deployed in polar environments - easing logistics, minimizing installation time and improving data quality return for these expensive deployments. All autonomous station designs are openly and freely available at the IRIS PASSCAL webpage (www.passcal.nmt.edu/polar/design-drawings). More information on GEOICE and data quality from various seismometer emplacements will be presented in other posters at this AGU meeting.

Application of Chemistry in Materials Research at NASA GRC

NASA Technical Reports Server (NTRS)

Kavandi, Janet L.

2016-01-01

Overview of NASA GRC Materials Development. New materials enabled by new chemistries offering unique properties and chemical processing techniques. Durability of materials in harsh environments requires understanding and modeling of chemical interaction of materials with the environment.

Attachment within life history theory: an evolutionary perspective on individual differences in attachment.

PubMed

Szepsenwol, Ohad; Simpson, Jeffry A

2018-03-15

In this article, we discuss theory and research on how individual differences in adult attachment mediate the adaptive calibration of reproductive strategies, cognitive schemas, and emotional expression and regulation. We first present an integration of attachment theory and life history theory. Then, we discuss how early harsh and/or unpredictable environments may promote insecure attachment by hampering parents' ability to provide sensitive and reliable care to their children. Finally, we discuss how, in the context of harsh and/or unpredictable environments, different types of insecure attachment (i.e. anxiety and avoidance) may promote evolutionary adaptive reproductive strategies, cognitive schemas, and emotional expression and regulation profiles. Copyright © 2018 Elsevier Ltd. All rights reserved.

Light guide technology: using light to enhance safety

NASA Astrophysics Data System (ADS)

Lerner, William S.

2009-05-01

When used to detect extreme temperatures in harsh environments, warning devices have been placed at a distance from the "danger zone" for several reasons. The inability to mix electricity with flammable, caustic, liquid or volatile substances, the limited heat tolerances exhibited by most light sources, and the susceptibility of light sources to damage from vibration, have made the placement of a warning light directly within these harsh environments impossible. This paper describes a system that utilizes a beam of light to provide just such a warning. This system can be used with hard-wired or wireless sensors, side-light illumination, image projection and image transfer. The entire system may be self-contained and portable.

An Embedded Laser Marking Controller Based on ARM and FPGA Processors

PubMed Central

Dongyun, Wang; Xinpiao, Ye

2014-01-01

Laser marking is an important branch of the laser information processing technology. The existing laser marking machine based on PC and WINDOWS operating system, are large and inconvenient to move. Still, it cannot work outdoors or in other harsh environments. In order to compensate for the above mentioned disadvantages, this paper proposed an embedded laser marking controller based on ARM and FPGA processors. Based on the principle of laser galvanometer scanning marking, the hardware and software were designed for the application. Experiments showed that this new embedded laser marking controller controls the galvanometers synchronously and could achieve precise marking. PMID:24772028

Modeling of a Von Platen-Munters diffusion absorption refrigeration cycle

NASA Astrophysics Data System (ADS)

Agostini, Bruno; Agostini, Francesco; Habert, Mathieu

2016-09-01

This article presents a thermodynamical model of a Von-Platen diffusion absorption refrigeration cycle for power electronics applications. It is first validated by comparison with data available in the literature for the classical water-ammonia-helium cycle for commercial absorption fridges. Then new operating conditions corresponding to specific ABB applications, namely high ambient temperature and new organic fluids combinations compatible with aluminium are simulated and discussed. The target application is to cool power electronics converters in harsh environments with high ambient temperature by providing refrigeration without compressor, for passive components losses of about 500 W, with a compact and low cost solution.

Optical fiber Fabry-Perot interferometry

NASA Astrophysics Data System (ADS)

Wang, Anbo

2014-06-01

Fiber Fabry-Perot (FP) interferometry is one of the most important tools for harsh environment sensing because of its great flexibility of sensor material selection, superior long-­-term stability, and nature of remote passive operation. Virginia Tech's Center for Photonics Technology has been involved in the research of this field for many years. After a quick review of the typical methods for the construction of F-P sensors, emphasis will be placed on the whitelight interferometry, which is perhaps the most robust interferometric sensor demodulation technique today. The recent discovery of an additional phase will be presented and its significance to the sensor demodulation will be discussed.

Shielded, Automated Umbilical Mechanism

NASA Technical Reports Server (NTRS)

Barron, Daniel R.; Morrill, Brion F.; Jasulaitis, Vytas

1995-01-01

Umbilical mechanism automatically connects and disconnects various fluid couplings and/or electrical contacts while shielding mating parts from debris. Reacts mating and demating loads internally, without additional supporting structures. All functions - extension of plug, mating, and movement of debris shields - actuated by single motor. If mechanism jams or fails at any point in sequence, override feature in drive train allows manual operation. Designed for service in outer space, where its shields protect against micrometeoroids, debris, ultraviolet radiation, and atomic oxygen. Used on Earth to connect or disconnect fluid or electrical utilities in harsh environments like those of nuclear powerplants or undersea construction sites, or in presence of radioactive, chemical, or biological hazards, for example.

OmniBird: a miniature PTZ NIR sensor system for UCAV day/night autonomous operations

NASA Astrophysics Data System (ADS)

Yi, Steven; Li, Hui

2007-04-01

Through a SBIR funding from NAVAIR, we have successfully developed an innovative, miniaturized, and lightweight PTZ UCAV imager called OmniBird for UCAV taxiing. The proposed OmniBird will be able to fit in a small space. The designed zoom capability allows it to acquire focused images for targets ranging from 10 to 250 feet. The innovative panning mechanism also allows the system to have a field of view of +/- 100 degrees within the provided limited spacing (6 cubic inches). The integrated optics, camera sensor, and mechanics solution will allow the OmniBird to stay optically aligned and shock-proof under harsh environments.

A Percutaneously Implantable Fetal Pacemaker

PubMed Central

Zhou, Li; Vest, Adriana N.; Chmait, Ramen H.; Bar-Cohen, Yaniv; Pruetz, Jay; Silka, Michael; Zheng, Kaihui; Peck, Ray; Loeb, Gerald E.

2015-01-01

A miniaturized, self-contained pacemaker that could be implanted with a minimally invasive technique would dramatically improve the survival rate for fetuses that develop hydrops fetalis as a result of congenital heart block. We are currently validating a device that we developed to address this bradyarrhythmia. Preclinical studies in a fetal sheep model are underway to demonstrate that the device can be implanted via a minimally invasive approach, can mechanically withstand the harsh bodily environment, can induce effective contractions of the heart muscle with an adequate safety factor, and can successfully operate for the required device lifetime of three months using the previously-developed closed loop transcutaneous recharging system. PMID:25570982

Silicon carbide novel optical sensor for combustion systems and nuclear reactors

NASA Astrophysics Data System (ADS)

Lim, Geunsik; Kar, Aravinda

2014-09-01

Crystalline silicon carbide is a wide bandgap semiconductor material with excellent optical properties, chemical inertness, radiation hardness and high mechanical strength at high temperatures. It is an excellent material platform for sensor applications in harsh environments such as combustion systems and nuclear reactors. A laser doping technique is used to fabricate SiC sensors for different combustion gases such as CO2, CO, NO and NO2. The sensor operates based on the principle of semiconductor optics, producing optical signal in contrast to conventional electrical sensors that produces electrical signal. The sensor response is measured with a low power He-Ne or diode laser.

Harsh parenting and serotonin transporter and BDNF Val66Met polymorphisms as predictors of adolescent depressive symptoms

PubMed Central

Koss, Kalsea J.; Cummings, E. Mark; Davies, Patrick T.; Hetzel, Susan; Cicchetti, Dante

2016-01-01

Objective Depressive symptoms are prevalent and rise during adolescence. The present study is a prospective investigation of environmental and genetic factors that contribute to the growth in depressive symptoms and the frequency of heightened symptoms during adolescence. Method Participants included 206 mother-father-adolescent triads (M age at T1 = 13.06 years, SD = .51, 52% female). Harsh parenting was observationally assessed during a family conflict paradigm. DNA was extracted from saliva samples and genotyped for the 5-HTTLPR and BDNF Val66Met polymorphisms. Adolescents provide self-reports of depressive symptoms annually across early adolescence. Results The results reveal gene-by-environment (GxE) interactions as predictors of adolescent depressive symptom trajectories in the context of harsh parenting as an environmental risk factor. A BDNF Val66Met x harsh parenting interaction predicted the rise in depressive symptoms across a three-year period while a 5-HTTLPR x harsh parenting interaction predicted greater frequency in elevated depressive symptoms. Conclusions The findings highlight the importance of unique genetic and environmental influences in the development and course of heightened depressive symptoms during adolescence. PMID:27736236

Youth temperament, harsh parenting, and variation in the oxytocin receptor gene forecast allostatic load during emerging adulthood.

PubMed

Brody, Gene H; Yu, Tianyi; Barton, Allen W; Miller, Gregory E; Chen, Edith

2017-08-01

An association has been found between receipt of harsh parenting in childhood and adult health problems. However, this research has been principally retrospective, has treated children as passive recipients of parental behavior, and has overlooked individual differences in youth responsivity to harsh parenting. In a 10-year multiple-wave prospective study of African American families, we addressed these issues by focusing on the influence of polymorphisms in the oxytocin receptor gene (OXTR), variants of which appear to buffer or amplify responses to environmental stress. The participants were 303 youths, with a mean age of 11.2 at the first assessment, and their parents, all of whom were genotyped for variations in the rs53576 (A/G) polymorphism. Teachers rated preadolescent (ages 11 to 13) emotionally intense and distractible temperaments, and adolescents (ages 15 and 16) reported receipt of harsh parenting. Allostatic load was assessed during young adulthood (ages 20 and 21). Difficult preadolescent temperament forecast elevated receipt of harsh parenting in adolescence, and adolescents who experienced harsh parenting evinced high allostatic load during young adulthood. However, these associations emerged only among children and parents who carried A alleles of the OXTR genotype. The results suggest the oxytocin system operates along with temperament and parenting to forecast young adults' allostatic load.

Passive and Self-Powered Autonomous Sensors for Remote Measurements

PubMed Central

Sardini, Emilio; Serpelloni, Mauro

2009-01-01

Autonomous sensors play a very important role in the environmental, structural, and medical fields. The use of this kind of systems can be expanded for several applications, for example in implantable devices inside the human body where it is impossible to use wires. Furthermore, they enable measurements in harsh or hermetic environments, such as under extreme heat, cold, humidity or corrosive conditions. The use of batteries as a power supply for these devices represents one solution, but the size, and sometimes the cost and unwanted maintenance burdens of replacement are important drawbacks. In this paper passive and self-powered autonomous sensors for harsh or hermetical environments without batteries are discussed. Their general architectures are presented. Sensing strategies, communication techniques and power management are analyzed. Then, general building blocks of an autonomous sensor are presented and the design guidelines that such a system must follow are given. Furthermore, this paper reports different proposed applications of autonomous sensors applied in harsh or hermetic environments: two examples of passive autonomous sensors that use telemetric communication are proposed, the first one for humidity measurements and the second for high temperatures. Other examples of self-powered autonomous sensors that use a power harvesting system from electromagnetic fields are proposed for temperature measurements and for airflow speeds. PMID:22399949

Passive and self-powered autonomous sensors for remote measurements.

PubMed

Sardini, Emilio; Serpelloni, Mauro

2009-01-01

Autonomous sensors play a very important role in the environmental, structural, and medical fields. The use of this kind of systems can be expanded for several applications, for example in implantable devices inside the human body where it is impossible to use wires. Furthermore, they enable measurements in harsh or hermetic environments, such as under extreme heat, cold, humidity or corrosive conditions. The use of batteries as a power supply for these devices represents one solution, but the size, and sometimes the cost and unwanted maintenance burdens of replacement are important drawbacks. In this paper passive and self-powered autonomous sensors for harsh or hermetical environments without batteries are discussed. Their general architectures are presented. Sensing strategies, communication techniques and power management are analyzed. Then, general building blocks of an autonomous sensor are presented and the design guidelines that such a system must follow are given. Furthermore, this paper reports different proposed applications of autonomous sensors applied in harsh or hermetic environments: two examples of passive autonomous sensors that use telemetric communication are proposed, the first one for humidity measurements and the second for high temperatures. Other examples of self-powered autonomous sensors that use a power harvesting system from electromagnetic fields are proposed for temperature measurements and for airflow speeds.

Drought-Tolerance of Wheat Improved by Rhizosphere Bacteria from Harsh Environments: Enhanced Biomass Production and Reduced Emissions of Stress Volatiles

PubMed Central

Timmusk, Salme; Abd El-Daim, Islam A.; Copolovici, Lucian; Tanilas, Triin; Kännaste, Astrid; Behers, Lawrence; Nevo, Eviatar; Seisenbaeva, Gulaim; Stenström, Elna; Niinemets, Ülo

2014-01-01

Water is the key resource limiting world agricultural production. Although an impressive number of research reports have been published on plant drought tolerance enhancement via genetic modifications during the last few years, progress has been slower than expected. We suggest a feasible alternative strategy by application of rhizospheric bacteria coevolved with plant roots in harsh environments over millions of years, and harboring adaptive traits improving plant fitness under biotic and abiotic stresses. We show the effect of bacterial priming on wheat drought stress tolerance enhancement, resulting in up to 78% greater plant biomass and five-fold higher survivorship under severe drought. We monitored emissions of seven stress-related volatiles from bacterially-primed drought-stressed wheat seedlings, and demonstrated that three of these volatiles are likely promising candidates for a rapid non-invasive technique to assess crop drought stress and its mitigation in early phases of stress development. We conclude that gauging stress by elicited volatiles provides an effectual platform for rapid screening of potent bacterial strains and that priming with isolates of rhizospheric bacteria from harsh environments is a promising, novel way to improve plant water use efficiency. These new advancements importantly contribute towards solving food security issues in changing climates. PMID:24811199

Effect of silicon and oxygen dopants on the stability of hydrogenated amorphous carbon under harsh environmental conditions

DOE PAGES

Mangolini, Filippo; Krick, Brandon A.; Jacobs, Tevis D. B.; ...

2017-12-27

Harsh environments pose materials durability challenges across the automotive, aerospace, and manufacturing sectors, and beyond. While amorphous carbon materials have been used as coatings in many environmentally-demanding applications owing to their unique mechanical, electrical, and optical properties, their limited thermal stability and high reactivity in oxidizing environments have impeded their use in many technologies. Silicon- and oxygen-containing hydrogenated amorphous carbon (a-C:H:Si:O) films are promising for several applications because of their higher thermal stability and lower residual stress compared to hydrogenated amorphous carbon (a-C:H). However, an understanding of their superior thermo-oxidative stability compared to a-C:H is lacking, as it has beenmore » inhibited by the intrinsic challenge of characterizing an amorphous, multi-component material. Here, we show that introducing silicon and oxygen in a-C:H slightly enhances the thermal stability in vacuum, but tremendously increases the thermo-oxidative stability and the resistance to degradation upon exposure to the harsh conditions of low Earth orbit (LEO). The latter is demonstrated by having mounted samples of a-C:H:Si:O on the exterior of the International Space Station via the Materials International Space Station (MISSE) mission 7b. Exposing lightly-doped a-C:H:Si:O to elevated temperatures under aerobic conditions or to LEO causes carbon volatilization in the near-surface region, producing a silica surface layer that protects the underlying carbon from further removal. In conclusion, these findings provide a novel physically-based understanding of the superior stability of a-C:H:Si:O in harsh environments compared to a-C:H.« less

Effect of silicon and oxygen dopants on the stability of hydrogenated amorphous carbon under harsh environmental conditions

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

Mangolini, Filippo; Krick, Brandon A.; Jacobs, Tevis D. B.

Harsh environments pose materials durability challenges across the automotive, aerospace, and manufacturing sectors, and beyond. While amorphous carbon materials have been used as coatings in many environmentally-demanding applications owing to their unique mechanical, electrical, and optical properties, their limited thermal stability and high reactivity in oxidizing environments have impeded their use in many technologies. Silicon- and oxygen-containing hydrogenated amorphous carbon (a-C:H:Si:O) films are promising for several applications because of their higher thermal stability and lower residual stress compared to hydrogenated amorphous carbon (a-C:H). However, an understanding of their superior thermo-oxidative stability compared to a-C:H is lacking, as it has beenmore » inhibited by the intrinsic challenge of characterizing an amorphous, multi-component material. Here, we show that introducing silicon and oxygen in a-C:H slightly enhances the thermal stability in vacuum, but tremendously increases the thermo-oxidative stability and the resistance to degradation upon exposure to the harsh conditions of low Earth orbit (LEO). The latter is demonstrated by having mounted samples of a-C:H:Si:O on the exterior of the International Space Station via the Materials International Space Station (MISSE) mission 7b. Exposing lightly-doped a-C:H:Si:O to elevated temperatures under aerobic conditions or to LEO causes carbon volatilization in the near-surface region, producing a silica surface layer that protects the underlying carbon from further removal. In conclusion, these findings provide a novel physically-based understanding of the superior stability of a-C:H:Si:O in harsh environments compared to a-C:H.« less

Electrodynamic Dust Shield for Space Applications

NASA Technical Reports Server (NTRS)

Mackey, Paul J.; Johansen, Michael R.; Olsen, Robert C.; Raines, Matthew G.; Phillips, James R., III; Cox, Rachel E.; Hogue, Michael D.; Pollard, Jacob R. S.; Calle, Carlos I.

2016-01-01

Dust mitigation technology has been highlighted by NASA and the International Space Exploration Coordination Group (ISECG) as a Global Exploration Roadmap (GER) critical technology need in order to reduce life cycle cost and risk, and increase the probability of mission success. The Electrostatics and Surface Physics Lab in Swamp Works at the Kennedy Space Center has developed an Electrodynamic Dust Shield (EDS) to remove dust from multiple surfaces, including glass shields and thermal radiators. Further development is underway to improve the operation and reliability of the EDS as well as to perform material and component testing outside of the International Space Station (ISS) on the Materials on International Space Station Experiment (MISSE). This experiment is designed to verify that the EDS can withstand the harsh environment of space and will look to closely replicate the solar environment experienced on the Moon.

GRC-2011-C-00579

NASA Image and Video Library

2007-03-28

Photos for Web Feature by Victoria (Tori) Woods; Micro-Electro Mechanical Systems (MEMS) using vacuum technology; fabricating High Temperature Electronics for Harsh Environments using silicon carbide substrates

Crew/Robot Coordinated Planetary EVA Operations at a Lunar Base Analog Site

NASA Technical Reports Server (NTRS)

Diftler, M. A.; Ambrose, R. O.; Bluethmann, W. J.; Delgado, F. J.; Herrera, E.; Kosmo, J. J.; Janoiko, B. A.; Wilcox, B. H.; Townsend, J. A.; Matthews, J. B.;

Oil Based Drilling Fluid Waste: An Overview on Environmentally Persistent Pollutants

NASA Astrophysics Data System (ADS)

Siddique, Shohel; Kwoffie, Lorraine; Addae-Afoakwa, Kofi; Yates, Kyari; Njuguna, James

2017-05-01

Operational discharges of spent drilling fluid, produced water, and accumulated drill cuttings from oil and gas industry are a continuous point source of environmental pollution. To meet the strict environmental standard for waste disposal, oil and gas industry is facing a numerous challenges in technological development to ensure a clean and safe environment. Oil and gas industry generates a large amount of spent drilling fluid, produced water, and drill cuttings, which are very different in every drilling operation in terms of composition and characterisation. This review article highlights the knowledge gap in identifying the different sources of waste streams in combined drilling waste. This paper also emphasises how different chemicals turn into environmentally significant pollutants after serving great performance in oil and gas drilling operations. For instance, oil based drilling fluid performs excellent in deeper drilling and drilling in the harsh geological conditions, but ended with (produces) a significant amount of persistent toxic pollutants in the environment. This review paper provides an overview on the basic concepts of drilling fluids and their functions, sources and characterisation of drilling wastes, and highlights some environmentally significant elements including different minerals present in drilling waste stream.

Packaging of structural health monitoring components

NASA Astrophysics Data System (ADS)

Kessler, Seth S.; Spearing, S. Mark; Shi, Yong; Dunn, Christopher T.

2004-07-01

Structural Health Monitoring (SHM) technologies have the potential to realize economic benefits in a broad range of commercial and defense markets. Previous research conducted by Metis Design and MIT has demonstrated the ability of Lamb waves methods to provide reliable information regarding the presence, location and type of damage in composite specimens. The present NSF funded program was aimed to study manufacturing, packaging and interface concepts for critical SHM components. The intention is to be able to cheaply manufacture robust actuating/sensing devices, and isolate them from harsh operating environments including natural, mechanical, or electrical extremes. Currently the issues related to SHM system durability have remained undressed. During the course of this research several sets of test devices were fabricated and packaged to protect the piezoelectric component assemblies for robust operation. These assemblies were then tested in hot and wet conditions, as well as in electrically noisy environments. Future work will aim to package the other supporting components such as the battery and wireless chip, as well as integrating all of these components together for operation. SHM technology will enable the reduction or complete elimination of scheduled inspections, and will allow condition-based maintenance for increased reliability and reduced overall life-cycle costs.

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.

Energy Systems Test Area (ESTA) Pyrotechnic Operations: User Test Planning Guide

NASA Technical Reports Server (NTRS)

Hacker, Scott

2012-01-01

The Johnson Space Center (JSC) has created and refined innovative analysis, design, development, and testing techniques that have been demonstrated in all phases of spaceflight. JSC is uniquely positioned to apply this expertise to components, systems, and vehicles that operate in remote or harsh environments. We offer a highly skilled workforce, unique facilities, flexible project management, and a proven management system. The purpose of this guide is to acquaint Test Requesters with the requirements for test, analysis, or simulation services at JSC. The guide includes facility services and capabilities, inputs required by the facility, major milestones, a roadmap of the facility s process, and roles and responsibilities of the facility and the requester. Samples of deliverables, facility interfaces, and inputs necessary to define the cost and schedule are included as appendices to the guide.

Harsh environment fiber optic connectors/testing

NASA Astrophysics Data System (ADS)

Parker, Douglas A.

2014-09-01

Fiber optic systems are used frequently in military, aerospace and commercial aviation programs. There is a long history of implementing fiber optic data transfer for aircraft control, for harsh environment use in local area networks and more recently for in-flight entertainment systems. The advantages of fiber optics include high data rate capacity, low weight, immunity to EMI/RFI, and security from signal tapping. Technicians must be trained particularly to install and maintain fiber systems, but it is not necessarily more difficult than wire systems. However, the testing of the fiber optic interconnection system must be conducted in a standardized manner to assure proper performance. Testing can be conducted with slight differences in the set-up and procedure that produce significantly different test results. This paper reviews various options of interconnect configurations and discusses how these options can affect the performance, maintenance required and longevity of a fiber optic system, depending on the environment. Proper test methods are discussed. There is a review of the essentials of proper fiber optic testing and impact of changing such test parameters as input launch conditions, wavelength considerations, power meter options and the basic methods of testing. This becomes important right from the start when the supplier test data differs from the user's data check upon receiving the product. It also is important in periodic testing. Properly conducting the fiber optic testing will eliminate confusion and produce meaningful test results for a given harsh environment application.

A wireless passive pressure microsensor fabricated in HTCC MEMS technology for harsh environments.

PubMed

Tan, Qiulin; Kang, Hao; Xiong, Jijun; Qin, Li; Zhang, Wendong; Li, Chen; Ding, Liqiong; Zhang, Xiansheng; Yang, Mingliang

2013-08-02

A wireless passive high-temperature pressure sensor without evacuation channel fabricated in high-temperature co-fired ceramics (HTCC) technology is proposed. The properties of the HTCC material ensure the sensor can be applied in harsh environments. The sensor without evacuation channel can be completely gastight. The wireless data is obtained with a reader antenna by mutual inductance coupling. Experimental systems are designed to obtain the frequency-pressure characteristic, frequency-temperature characteristic and coupling distance. Experimental results show that the sensor can be coupled with an antenna at 600 °C and max distance of 2.8 cm at room temperature. The senor sensitivity is about 860 Hz/bar and hysteresis error and repeatability error are quite low.

The design and implementation of photoacoustic based laser warning receiver for harsh environments

NASA Astrophysics Data System (ADS)

El-Sherif, Ashraf F.; Ayoub, H. S.; El-Sharkawy, Yasser H.; Gomaa, Walid; Hassan, H. H.

2018-01-01

This paper discusses the implementation of new type of laser warning receiver (LWR) system, based on the detection of photoacoustic signals, induced by high power infrared laser designators pulses on target's surfaces. This system appends conventional optoelectronic based LWR to decrease the false alarm rate (FAR) in harsh environments, where ambient conditions are expected to obstruct optical LWR. To improve the sensitivity of the photoacoustic based LWR system, some metallic and polymeric target shielding materials were studied, in order to cover a friendly civil structure, vehicle or a maritime entity with a low cost large area acoustic detector array shield. A thermographic investigation of target surface material- laser reaction, signal processing and system configuration and functional analysis are also presented.

Surface acoustic wave devices for harsh environment wireless sensing

DOE PAGES

Greve, David W.; Chin, Tao -Lun; Zheng, Peng; ...

2013-05-24

In this study, langasite surface acoustic wave devices can be used to implement harsh environment wireless sensing of gas concentration and temperature. This paper reviews prior work on the development of langasite surface acoustic wave devices, followed by a report of recent progress toward the implementation of oxygen gas sensors. Resistive metal oxide films can be used as the oxygen sensing film, although development of an adherent barrier layer will be necessary with the sensing layers studied here to prevent interaction with the langasite substrate. Experimental results are presented for the performance of a langasite surface acoustic wave oxygen sensormore » with tin oxide sensing layer, and these experimental results are correlated with direct measurements of the sensing layer resistivity.« less

Qualification and Testing of Quantum Cascade Lasers for Harsh Environments

NASA Astrophysics Data System (ADS)

Brauer, C. S.; Myers, T. L.; Cannon, B. D.; Anderson, C. G.; Crowther, B. G.; Hansen, S.

2014-12-01

Quantum cascade lasers (QCLs) offer the potential for the development of novel, laser-based instruments for both terrestrial and space applications. In order to withstand harsh conditions encountered in these environments, lasers must be robust, and rigorous testing is required before new systems can be utilized. A particular concern for space applications is the potential damage to laser performance caused by radiation exposure. While the effects of radiation exposure in diode lasers have been studied extensively, the effect on QCLs, which are fundamentally different from diode lasers, is not well known. We thus present work to quantify the performance of QCLs after exposure to moderate and high levels of radiation from different sources, including protons and gamma rays, to determine the effects of radiation damage.

Lunar Communication Terminals for NASA Exploration Missions: Needs, Operations Concepts and Architectures

NASA Technical Reports Server (NTRS)

Bhasin, Kul B.; Warner, Joseph D.; Anderson, Lynn M.

2008-01-01

NASA is conducting architecture studies prior to deploying a series of short- and long-duration human and robotic missions for the exploration of the Moon and Mars under the Vision for Space Exploration Initiative. A key objective of these missions is to establish and expand, through a series of launches, a system of systems approach to exploration capabilities and science return. The systems identified were Crew Exploration Vehicles, crew and cargo launch vehicles, crew EVA suits, crew and cargo landers, habitats, mobility carriers, and small, pressurized rovers. Multiple space communication networks and systems, deployed over time, will support these space exploration systems of systems. Each deployment phase will support interoperability of components and provide 20 years of legacy systems. In this paper, we describe the modular lunar communications terminals needed for the emerging lunar mission operational scenarios. These lunar communication terminals require flexibility for use in stationary, integrated, and mobile environments. They will support links directly to Earth, to lunar relay satellites, to astronauts and to fixed and mobile lunar surface systems. The operating concepts and traffic models are presented for these terminals within variety of lunar scenarios. A preliminary architecture is outlined, providing for suitable long-duration operations in the harsh lunar environment.

Characterization of interdigitated electrode piezoelectric fiber composites under high electrical and mechanical loading

NASA Astrophysics Data System (ADS)

Rodgers, John P.; Bent, Aaron A.; Hagood, Nesbitt W.

1996-05-01

The primary objective of this work is to develop a standard methodology for characterizing structural actuation systems intended for operation in high electrical and mechanical loading environments. The designed set of tests evaluates the performance of the active materials system under realistic operating conditions. The tests are also used to characterize piezoelectric fiber composites which have been developed as an alternative to monolithic piezoceramic wafers for structural actuation applications. The performance of this actuator system has been improved using an interdigitated electrode pattern, which orients the primary component of the electric field into the plane of the structure, enabling the use of the primary piezoelectric effect along the active fibers. One possible application of this technology is in the integral twist actuation of helicopter rotor blades for higher harmonic control. This application requires actuators which can withstand the harsh rotor blade operating environment. This includes large numbers of electrical and mechanical cycles with considerable centripetal and bending loads. The characterization tests include standard active material tests as well as application-driven tests which evaluate the performance of the actuators during simulated operation. Test results for several actuator configurations are provided, including S2 glass- reinforced and E-glass laminated actuators. The study concludes that the interdigitated electrode piezoelectric fiber composite actuator has great potential for high loading applications.

Arcjet Testing of Micro-Meteoroid Impacted Thermal Protection Materials

NASA Technical Reports Server (NTRS)

Agrawal, Parul; Munk, Michelle M.; Glaab, Louis J.

2013-01-01

There are several harsh space environments that could affect thermal protection systems and in turn pose risks to the atmospheric entry vehicles. These environments include micrometeoroid impact, extreme cold temperatures, and ionizing radiation during deep space cruise, all followed by atmospheric entry heating. To mitigate these risks, different thermal protection material samples were subjected to multiple tests, including hyper velocity impact, cold soak, irradiation, and arcjet testing, at various NASA facilities that simulated these environments. The materials included a variety of honeycomb packed ablative materials as well as carbon-based non-ablative thermal protection systems. The present paper describes the results of the multiple test campaign with a focus on arcjet testing of thermal protection materials. The tests showed promising results for ablative materials. However, the carbon-based non-ablative system presented some concerns regarding the potential risks to an entry vehicle. This study provides valuable information regarding the capability of various thermal protection materials to withstand harsh space environments, which is critical to sample return and planetary entry missions.

A low cost, high precision extreme/harsh cold environment, autonomous sensor data gathering and transmission platform.

NASA Astrophysics Data System (ADS)

Chetty, S.; Field, L. A.

2014-12-01

SWIMS III, is a low cost, autonomous sensor data gathering platform developed specifically for extreme/harsh cold environments. Arctic ocean's continuing decrease of summer-time ice is related to rapidly diminishing multi-year ice due to the effects of climate change. Ice911 Research aims to develop environmentally inert materials that when deployed will increase the albedo, enabling the formation and/preservation of multi-year ice. SWIMS III's sophisticated autonomous sensors are designed to measure the albedo, weather, water temperature and other environmental parameters. This platform uses low cost, high accuracy/precision sensors, extreme environment command and data handling computer system using satellite and terrestrial wireless solution. The system also incorporates tilt sensors and sonar based ice thickness sensors. The system is light weight and can be deployed by hand by a single person. This presentation covers the technical, and design challenges in developing and deploying these platforms.

The Link between Harsh Home Environments and Negative Academic Trajectories is Exacerbated by Victimization in the Elementary School Peer Group

PubMed Central

Schwartz, David; Lansford, Jennifer E.; Dodge, Kenneth A.; Pettit, Gregory S.; Bates, John E.

2012-01-01

This paper presents a prospective investigation focusing on the moderating role of peer victimization on associations between harsh home environments in the preschool years and academic trajectories during elementary school. The participants were 388 children (198 boys, 190 girls) who we recruited as part of an ongoing multisite longitudinal investigation. Preschool home environment was assessed with structured interviews and questionnaires completed by parents. Peer victimization was assessed with a peer nomination inventory that was administered when the average age of the participants was approximately 8.5 years. Grade point averages (GPA) were obtained from reviews of school records, conducted for seven consecutive years. Indicators of restrictive punitive discipline and exposure to violence were associated with within-subject declines in academic functioning over seven years. However, these effects were exacerbated for those children who had also experienced victimization in the peer group during the intervening years. PMID:22506975

Rayleigh Scattering Diagnostic for Measurement of Temperature and Velocity in Harsh Environments

NASA Technical Reports Server (NTRS)

Seasholtz, Richard G.; Greer, Lawrence C., III

1998-01-01

A molecular Rayleigh scattering system for temperature and velocity measurements in unseeded flows is described. The system is capable of making measurements in the harsh environments commonly found in aerospace test facilities, which may have high acoustic sound levels, varying temperatures, and high vibration levels. Light from an argon-ion laser is transmitted via an optical fiber to a remote location where two flow experiments were located. One was a subsonic free air jet; the second was a low-speed heated airjet. Rayleigh scattered light from the probe volume was transmitted through another optical fiber from the remote location to a controlled environment where a Fabry-Perot interferometer and cooled CCD camera were used to analyze the Rayleigh scattered light. Good agreement between the measured velocity and the velocity calculated from isentropic flow relations was demonstrated (less than 5 m/sec). The temperature measurements, however, exhibited systematic errors on the order of 10-15%.

Measurement and analysis of the conversion gain degradation of the CIS detectors in harsh radiation environments

NASA Astrophysics Data System (ADS)

Wang, Zujun; Xue, Yuanyuan; Guo, Xiaoqiang; Bian, Jingying; Yao, Zhibin; He, Baoping; Ma, Wuying; Sheng, Jiangkun; Dong, Guantao; Liu, Yan

2018-07-01

The conversion gain of the CMOS image sensor (CIS) is one of the most important key parameters to the CIS detector. The conversion gain degradation induced by radiation damage will seriously affect the performances of the CIS detector. The experiments of the CISs irradiated by protons, neutrons, and gamma rays are presented. The CISs have 4 Megapixels and pinned photodiode (PPD) pixel architecture with a standard 0.18 μm CMOS technology. The conversion gains versus the proton fluence (including the proton ionizing dose), neutron fluence and gamma total ionizing dose are presented, respectively. The mechanisms of the conversion gain degradation induced by radiation damage are analyzed in details. The investigations will help to improve the PPD CIS detector design, reliability and applicability for applications in the harsh radiation environments such as space and nuclear environments.

Demonstrated Performance of the Solar Probe Cup

NASA Astrophysics Data System (ADS)

Case, A. W.; Kasper, J. C.; Korreck, K. E.; Stevens, M. L.; Daigneau, P.; Freeman, M.; Caldwell, D.; Gauron, T.; Wright, K. H.; Bergner, H.; Cirtain, J. W.; Larson, D.; Brodu, E.; Balat-Pichelin, M.

2013-12-01

The Solar Probe Cup (SPC) is a Faraday Cup being developed for the Solar Probe Plus (SPP) mission. SPP will be the first spacecraft to directly measure the solar environment near the Alfven point in the atmosphere of the Sun, approaching to within 10 solar radii of the center of the Sun. In order to make the observations of radially flowing solar wind needed to address questions of coronal and solar wind heating and acceleration, SPC must operate while looking directly at the Sun. As a result, SPC will face a harsh and unprecidented environment, with component temperatures exceeding 1000C at closest approach. SPC is similar in design and operation to the two Faraday Cup instruments on the Wind spacecraft, which have been making stable measurements of the solar wind near Earth for two decades, with two key differences. SPC must survive and operate at extreme temperatures due to the levels of solar flux near the Sun, and it must record the solar wind approximately one thousand times faster than the instruments on Wind to keep up with the rapid variations expected near the Sun. We present results of a demonstration model of SPC operated in laboratory reproductions of the near-Sun environment. In the last year, SPC has been exposed to simulated encounter solar fluxes and resulting temperature profiles using a vaccum chamber and modified IMAX film projectors. In addition, SPC has been exposed to realistic ion beams. We show that SPC can operate in these environments, and make the measurements required for the sucess of the Solar Probe mission. Based on the performance of our prototype, the expected cadence and sensitivity of SPC will be discussed, with a focus on its ability to distinguish between models of heating in the solar corona.

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

Burgett, Eric; Al-Sheikhly, Mohamad; Summers, Christopher

An advanced in-pile multi-parameter reactor monitoring system is being proposed in this funding opportunity. The proposed effort brings cutting edge, high-fidelity optical measurement systems into the reactor environment in an unprecedented fashion, including in-core, in-cladding and in-fuel pellet itself. Unlike instrumented leads, the proposed system provides a unique solution to a multi-parameter monitoring need in core while being minimally intrusive in the reactor core. Detector designs proposed herein can monitor fuel compression and expansion in both the radial and axial dimensions as well as monitor linear power profiles and fission rates during the operation of the reactor. In addition tomore » pressure, stress, strain, compression, neutron flux, neutron spectra, and temperature can be observed inside the fuel bundle and fuel rod using the proposed system. The proposed research aims at developing radiation-hard, harsh-environment multi-parameter systems for insertion into the reactor environment. The proposed research holds the potential to drastically increase the fidelity and precision of in-core instrumentation with little or no impact in the neutron economy in the reactor environment while providing a measurement system capable of operation for entire operating cycles. Significant work has been done over the last few years on the use of nanoparticle-based scintillators. Through the use of metamaterials, the PIs aim to develop planar neutron detectors and large-volume neutron detectors. These detectors will have high efficiencies for neutron detection and will have a high gamma discrimination capability.« less

Microwave Radiometers from 0.6 to 22 GHz for Juno, A Polar Orbiter Around Jupiter

NASA Technical Reports Server (NTRS)

Pingree, P.; Janssen, M.; Oswald, J.; Brown, S.; Chen, J.; Hurst, K.; Kitiyakara, A.; Maiwald, F.; Smith, S.

2008-01-01

A compact instrument called the MWR (MicroWave Radiometer) is under development at JPL for Juno, the next NASA New Frontiers mission, scheduled to launch in 2011. It's purpose is to measure the thermal emission from Jupiter's atmosphere at six selected frequencies from 0.6 to 22 GHz, operating in direct detection mode, in order to quantify the distributions and abundances of water and ammonia in Jupiter's atmosphere. The goal is to understand the previously unobserved dynamics of the sub-cloud atmosphere, and to discriminate among models for planetary formation in our solar system. As part of a deep space mission aboard a solar-powered spacecraft, MWR is designed to be compact, lightweight, and low power. The receivers and control electronics are protected by a radiation-shielding enclosure on the Juno spacecraft that would provide a benign and stable operating temperature environment. All antennas and RF transmission lines outside the vault must withstand low temperatures and the harsh radiation environment surrounding Jupiter. This paper describes the concept of the MWR instrument and presents results of one breadboard receiver channel.

Microwave Radiometers from 0.6 to 22 GHz for Juno, a Polar Orbiter around Jupiter

NASA Technical Reports Server (NTRS)

Pingree, Paula J.; Janssen, M.; Oswald, J.; Brown, S.; Chen, J.; Hurst, K.; Kitiyakara, A.; Maiwald, F.; Smith, S.

2008-01-01

A compact instrument called the MWR (microwave radiometer) is under development at JPL for Juno, the next NASA new frontiers mission, scheduled to launch in 2011. It's purpose is to measure the thermal emission from Jupiter's atmosphere at six selected frequencies from 0.6 to 22 GHz, operating in direct detection mode, in order to quantify the distributions and abundances of water and ammonia in Jupiter's atmosphere. The goal is to understand the previously unobserved dynamics of the sub-cloud atmosphere, and to discriminate among models for planetary formation in our solar system. as part of a deep space mission aboard a solar-powered spacecraft, MWR is designed to be compact, lightweight, and low power. The receivers and control electronics are protected by a radiation-shielding enclosure on the Juno spacecraft that also provides for a benign and stable operating temperature environment. All antennas and RF transmission lines outside the vault must withstand low temperatures and the harsh radiation environment surrounding Jupiter. This paper describes the concept of the MWR instrument and presents results of one breadboard receiver channel.

Facile Fabrication of a Polyethylene Mesh for Oil/Water Separation in a Complex Environment.

PubMed

Zhao, Tianyi; Zhang, Dongmei; Yu, Cunming; Jiang, Lei

2016-09-14

Low cost, eco-friendly, and easily scaled-up processes are needed to fabricate efficient oil/water separation materials, especially those useful in harsh environments such as highly acidic, alkaline, and salty environments, to deal with serious oil spills and industrial organic pollutants. Herein, a highly efficient oil/water separation mesh with durable chemical stability was fabricated by simply scratching and pricking a conventional polyethylene (PE) film. Multiscaled morphologies were obtained by this scratching and pricking process and provided the mesh with a special wettability performance termed superhydrophobicity, superoleophilicity, and low water adhesion, while the inert chemical properties of PE delivered chemical etching resistance to the fabricated mesh. In addition to a highly efficient oil/corrosive liquid separation, the fabricated PE mesh was also reusable and exhibited ultrafast oil/water separation solely by gravity. The easy operation, chemical durability, reusability, and efficiency of the novel PE mesh give it high potential for use in industrial and consumer applications.

Childhood temperament and family environment as predictors of internalizing and externalizing trajectories from ages 5 to 17.

PubMed

Leve, Leslie D; Kim, Hyoun K; Pears, Katherine C

2005-10-01

Childhood temperament and family environment have been shown to predict internalizing and externalizing behavior; however, less is known about how temperament and family environment interact to predict changes in problem behavior. We conducted latent growth curve modeling on a sample assessed at ages 5, 7, 10, 14, and 17 (N = 337). Externalizing behavior decreased over time for both sexes, and internalizing behavior increased over time for girls only. Two childhood variables (fear/shyness and maternal depression) predicted boys' and girls' age-17 internalizing behavior, harsh discipline uniquely predicted boys' age-17 internalizing behavior, and maternal depression and lower family income uniquely predicted increases in girls' internalizing behavior. For externalizing behavior, an array of temperament, family environment, and Temperament x Family Environment variables predicted age-17 behavior for both sexes. Sex differences were present in the prediction of externalizing slopes, with maternal depression predicting increases in boys' externalizing behavior only when impulsivity was low, and harsh discipline predicting increases in girls' externalizing behavior only when impulsivity was high or when fear/shyness was low.

Development of self-powered wireless high temperature electrochemical sensor for in situ corrosion monitoring of coal-fired power plant.

PubMed

Aung, Naing Naing; Crowe, Edward; Liu, Xingbo

2015-03-01

Reliable wireless high temperature electrochemical sensor technology is needed to provide in situ corrosion information for optimal predictive maintenance to ensure a high level of operational effectiveness under the harsh conditions present in coal-fired power generation systems. This research highlights the effectiveness of our novel high temperature electrochemical sensor for in situ coal ash hot corrosion monitoring in combination with the application of wireless communication and an energy harvesting thermoelectric generator (TEG). This self-powered sensor demonstrates the successful wireless transmission of both corrosion potential and corrosion current signals to a simulated control room environment. Copyright © 2014 ISA. All rights reserved.

Welding in Space: Lessons Learned for Future In Space Repair Development

NASA Technical Reports Server (NTRS)

Russell, C. K.; Nunes, A. C.; Zimmerman, F. R.

2005-01-01

Welds have been made in the harsh environment of space only twice in the history of manned space flight. The United States conducted the M5 12 experiment on Skylab and the former Soviet Union conducted an Extravehicular Activity. Both experiments demonstrated electron beam welding. A third attempt to demonstrate and advance space welding was made by the Marshall Space Flight Center in the 90's but the experiment was demanifested as a Space Shuttle payload. This presentation summarizes the lessons learned from these three historical experiences in the areas of safety, design, operations and implementation so that welding in space can become an option for in space repair applications.

Evaluation of COTS Electronic Parts for Extreme Temperature Use in NASA Missions

NASA Technical Reports Server (NTRS)

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

2008-01-01

Electronic systems capable of extreme temperature operation are required for many future NASA space exploration missions where it is desirable to have smaller, lighter, and less expensive spacecraft and probes. Presently, spacecraft on-board electronics are maintained at about room temperature by use of thermal control systems. An Extreme Temperature Electronics Program at the NASA Glenn Research Center focuses on development of electronics suitable for space exploration missions. The effects of exposure to extreme temperatures and thermal cycling are being investigated for commercial-off-the-shelf components as well as for components specially developed for harsh environments. An overview of this program along with selected data is presented.

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

Stutman, D.; Tritz, K.; Finkenthal, M.

New diagnostic and sensor designs are needed for future burning plasma (BP) fusion experiments, having good space and time resolution and capable of prolonged operation in the harsh BP environment. We evaluate the potential of multi-energy x-ray imaging with filtered detector arrays for BP diagnostic and control. Experimental studies show that this simple and robust technique enables measuring with good accuracy, speed, and spatial resolution the T{sub e} profile, impurity content, and MHD activity in a tokamak. Applied to the BP this diagnostic could also serve for non-magnetic sensing of the plasma position, centroid, ELM, and RWM instability. BP compatiblemore » x-ray sensors are proposed using 'optical array' or 'bi-cell' detectors.« less

A portable W-band radar system for enhancement of infrared vision in fire fighting operations

NASA Astrophysics Data System (ADS)

Klenner, Mathias; Zech, Christian; Hülsmann, Axel; Kühn, Jutta; Schlechtweg, Michael; Hahmann, Konstantin; Kleiner, Bernhard; Ulrich, Michael; Ambacher, Oliver

2016-10-01

In this paper, we present a millimeter wave radar system which will enhance the performance of infrared cameras used for fire-fighting applications. The radar module is compact and lightweight such that the system can be combined with inertial sensors and integrated in a hand-held infrared camera. This allows for precise distance measurements in harsh environmental conditions, such as tunnel or industrial fires, where optical sensors are unreliable or fail. We discuss the design of the RF front-end, the antenna and a quasi-optical lens for beam shaping as well as signal processing and demonstrate the performance of the system by in situ measurements in a smoke filled environment.

An Adaptive INS-Aided PLL Tracking Method for GNSS Receivers in Harsh Environments.

PubMed

Cong, Li; Li, Xin; Jin, Tian; Yue, Song; Xue, Rui

2016-01-23

As the weak link in global navigation satellite system (GNSS) signal processing, the phase-locked loop (PLL) is easily influenced with frequent cycle slips and loss of lock as a result of higher vehicle dynamics and lower signal-to-noise ratios. With inertial navigation system (INS) aid, PLLs' tracking performance can be improved. However, for harsh environments with high dynamics and signal attenuation, the traditional INS-aided PLL with fixed loop parameters has some limitations to improve the tracking adaptability. In this paper, an adaptive INS-aided PLL capable of adjusting its noise bandwidth and coherent integration time has been proposed. Through theoretical analysis, the relation between INS-aided PLL phase tracking error and carrier to noise density ratio (C/N₀), vehicle dynamics, aiding information update time, noise bandwidth, and coherent integration time has been built. The relation formulae are used to choose the optimal integration time and bandwidth for a given application under the minimum tracking error criterion. Software and hardware simulation results verify the correctness of the theoretical analysis, and demonstrate that the adaptive tracking method can effectively improve the PLL tracking ability and integrated GNSS/INS navigation performance. For harsh environments, the tracking sensitivity is increased by 3 to 5 dB, velocity errors are decreased by 36% to 50% and position errors are decreased by 6% to 24% when compared with other INS-aided PLL methods.

Harsh Parenting and Fearfulness in Toddlerhood Interact to Predict Amplitudes of Preschool Error-Related Negativity

PubMed Central

Brooker, Rebecca J.; Buss, Kristin A.

2014-01-01

Temperamentally fearful children are at increased risk for the development of anxiety problems relative to less-fearful children. This risk is even greater when early environments include high levels of harsh parenting behaviors. However, the mechanisms by which harsh parenting may impact fearful children’s risk for anxiety problems are largely unknown. Recent neuroscience work has suggested that punishment is associated with exaggerated error-related negativity (ERN), an event-related potential linked to performance monitoring, even after the threat of punishment is removed. In the current study, we examined the possibility that harsh parenting interacts with fearfulness, impacting anxiety risk via neural processes of performance monitoring. We found that greater fearfulness and harsher parenting at 2 years of age predicted greater fearfulness and greater ERN amplitudes at age 4. Supporting the role of cognitive processes in this association, greater fearfulness and harsher parenting also predicted less efficient neural processing during preschool. This study provides initial evidence that performance monitoring may be a candidate process by which early parenting interacts with fearfulness to predict risk for anxiety problems. PMID:24721466

Antiresonant reflecting guidance mechanism in hollow-core fiber for gas pressure sensing.

PubMed

Hou, Maoxiang; Zhu, Feng; Wang, Ying; Wang, Yiping; Liao, Changrui; Liu, Shen; Lu, Peixiang

2016-11-28

A gas pressure sensor based on an antiresonant reflecting guidance mechanism in a hollow-core fiber (HCF) with an open microchannel is experimentally demonstrated for gas pressure sensing. The microchannel was created on the ring cladding of the HCF by femtosecond laser drilling to provide an air-core pressure equivalent to the external environment. The HCF cladding functions as an antiresonant reflecting waveguide, which induces sharp periodic lossy dips in the transmission spectrum. The proposed sensor exhibits a high pressure sensitivity of 3.592 nm/MPa and a low temperature cross-sensitivity of 7.5 kPa/°C. Theoretical analysis indicates that the observed high gas pressure sensitivity originates from the pressure induced refractive index change of the air in the hollow-core. The good operation durability and fabrication simplicity make the device an attractive candidate for reliable and highly sensitive gas pressure measurement in harsh environments.

Applications of piezoelectric materials in oilfield services.

PubMed

Goujon, Nicolas; Hori, Hiroshi; Liang, Kenneth K; Sinha, Bikash K

2012-09-01

Piezoelectric materials are used in many applications in the oilfield services industry. Four illustrative examples are given in this paper: marine seismic survey, precision pressure measurement, sonic logging-while-drilling, and ultrasonic bore-hole imaging. In marine seismics, piezoelectric hydrophones are deployed on a massive scale in a relatively benign environment. Hence, unit cost and device reliability are major considerations. The remaining three applications take place downhole in a characteristically harsh environment with high temperature and high pressure among other factors. The number of piezoelectric devices involved is generally small but otherwise highly valued. The selection of piezoelectric materials is limited, and the devices have to be engineered to withstand the operating conditions. With the global demand for energy increasing in the foreseeable future, the search for hydrocarbon resources is reaching into deeper and hotter wells. There is, therefore, a continuing and pressing need for high-temperature and high-coupling piezoelectric materials.

Simulation-Based Verification of Autonomous Controllers via Livingstone PathFinder

NASA Technical Reports Server (NTRS)

Lindsey, A. E.; Pecheur, Charles

2004-01-01

AI software is often used as a means for providing greater autonomy to automated systems, capable of coping with harsh and unpredictable environments. Due in part to the enormous space of possible situations that they aim to addrs, autonomous systems pose a serious challenge to traditional test-based verification approaches. Efficient verification approaches need to be perfected before these systems can reliably control critical applications. This publication describes Livingstone PathFinder (LPF), a verification tool for autonomous control software. LPF applies state space exploration algorithms to an instrumented testbed, consisting of the controller embedded in a simulated operating environment. Although LPF has focused on NASA s Livingstone model-based diagnosis system applications, the architecture is modular and adaptable to other systems. This article presents different facets of LPF and experimental results from applying the software to a Livingstone model of the main propulsion feed subsystem for a prototype space vehicle.

GEM detectors development for radiation environment: neutron tests and simulations

NASA Astrophysics Data System (ADS)

Chernyshova, Maryna; Jednoróg, Sławomir; Malinowski, Karol; Czarski, Tomasz; Ziółkowski, Adam; Bieńkowska, Barbara; Prokopowicz, Rafał; Łaszyńska, Ewa; Kowalska-Strzeciwilk, Ewa; Poźniak, Krzysztof T.; Kasprowicz, Grzegorz; Zabołotny, Wojciech; Wojeński, Andrzej; Krawczyk, Rafał D.; Linczuk, Paweł; Potrykus, Paweł; Bajdel, Barcel

2016-09-01

One of the requests from the ongoing ITER-Like Wall Project is to have diagnostics for Soft X-Ray (SXR) monitoring in tokamak. Such diagnostics should be focused on tungsten emission measurements, as an increased attention is currently paid to tungsten due to a fact that it became a main candidate for the plasma facing material in ITER and future fusion reactor. In addition, such diagnostics should be able to withstand harsh radiation environment at tokamak during its operation. The presented work is related to the development of such diagnostics based on Gas Electron Multiplier (GEM) technology. More specifically, an influence of neutron radiation on performance of the GEM detectors is studied both experimentally and through computer simulations. The neutron induced radioactivity (after neutron source exposure) was found to be not pronounced comparing to an impact of other secondary neutron reaction products (during the exposure).

Mid-infrared Laser Absorption Diagnostics for Detonation Studies

NASA Astrophysics Data System (ADS)

Spearrin, R. M.; Goldenstein, C. S.; Jeffries, J. B.; Hanson, R. K.

Detonation-based engines represent a challenging application for diagnostics due to the wide range of thermodynamic conditions involved (T~500-3000 K, P~2-60 atm) and the short time scales of change (~10- 6 to 10- 4 sec) associated with such systems. Non-intrusive laser absorption diagnostics can provide high time-resolution and have been employed extensively in shock tube kinetics experiments (P~1-20 atm), offering high potential for application in detonation environments with modest utilization to date [1-4]. Limiting factors in designing effective tunable laser absorption sensors for detonation engines can be divided into two sets of challenges: high-pressure, high-temperature absorption spectroscopy and harsh thermo-mechanical environments. The present work, conducted in a high-pressure shock tube and operating detonation combustor, addresses both sets of difficulties, with the objective of developing time-resolved, in-situ temperature and concentration sensors for detonation studies.

Development and Life Prediction of Erosion Resistant Turbine Low Conductivity Thermal Barrier Coatings

NASA Technical Reports Server (NTRS)

Zhu, Dongming; Miller, Robert A.; Kuczmarski, Maria A.

2010-01-01

Future rotorcraft propulsion systems are required to operate under highly-loaded conditions and in harsh sand erosion environments, thereby imposing significant material design and durability issues. The incorporation of advanced thermal barrier coatings (TBC) in high pressure turbine systems enables engine designs with higher inlet temperatures, thus improving the engine efficiency, power density and reliability. The impact and erosion resistance of turbine thermal barrier coating systems are crucial to the turbine coating technology application, because a robust turbine blade TBC system is a prerequisite for fully utilizing the potential coating technology benefit in the rotorcraft propulsion. This paper describes the turbine blade TBC development in addressing the coating impact and erosion resistance. Advanced thermal barrier coating systems with improved performance have also been validated in laboratory simulated engine erosion and/or thermal gradient environments. A preliminary life prediction modeling approach to emphasize the turbine blade coating erosion is also presented.

Effects of Harsh and Unpredictable Environments in Adolescence on Development of Life History Strategies

PubMed Central

Figueredo, Aurelio José; Ellis, Bruce J.

2010-01-01

The National Longitudinal Study of Adolescent Health data were used to test predictions from life history theory. We hypothesized that (1) in young adulthood an emerging life history strategy would exist as a common factor underlying many life history traits (e.g., health, relationship stability, economic success), (2) both environmental harshness and unpredictability would account for unique variance in expression of adolescent and young adult life history strategies, and (3) adolescent life history traits would predict young adult life history strategy. These predictions were supported. The current findings suggest that the environmental parameters of harshness and unpredictability have concurrent effects on life history development in adolescence, as well as longitudinal effects into young adulthood. In addition, life history traits appear to be stable across developmental time from adolescence into young adulthood. PMID:20634914

77 FR 14569 - Notice of Intent To Grant Exclusive License

Federal Register 2010, 2011, 2012, 2013, 2014

2012-03-12

... Direct Chip Attach Packaging Methodologies and Apparatuses for Harsh Environments, LEW 17,256-1, to... equipment; semiconductor manufacturing; material manufacturing such as metallurgy, refractory processes, and...

Prediction of the thermal annealing of thick oxide metal-oxide-semiconductor dosimeters irradiated in a harsh radiation environment

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

Ravotti, F.; Glaser, M.; Saigne, F.

Radiation-sensing metal-oxide-semiconductor field-effect transistors produced by the laboratory LAAS-CNRS were exposed to a harsh hadron field that represents the real radiation environment expected at the CERN Large Hadron Collider experiments. The long-term stability of the transistor's I{sub ds}-V{sub gs} characteristic was investigated using the isochronal annealing technique. In this work, devices exposed to high intensity hadron levels ({phi}{>=}10{sup 12} neutrons/cm{sup 2}) show evidences of displacement damages in the I{sub ds}-V{sub gs} annealing behavior. By comparing experimental and simulated results over 14 months, the isochronal annealing method, originally devoted to oxide trapped charge, is shown to enable prediction of the recoverymore » of silicon bulk defects.« less

Investigation on harsh environmental effects on polymer fiber optic link for aircraft systems

NASA Astrophysics Data System (ADS)

Cherian, Sandy; Spangenberg, Holger; Caspary, Reinhard

2014-09-01

To integrate polymer fiber based physical layer for avionic data network, it is necessary to understand the impact and cause of harsh environments on polymer fiber optic components and harnesses. Since temperature and vibration have a significant influence, we investigate the variation in optical transmittance and monitor the endurance of different types of connector and splices under extreme aircraft environments. Presently, there is no specific aerospace standard for the application of polymer fiber and components in the aircraft data network. Therefore, in the paper we examine and define the thermal cycling and vibration measurement set up and methods to evaluate the performance capability of the physical layer of the data network. Some of the interesting results observed during the measurements are also presented.

Instrumentation and Controls Division Overview: Sensors Development for Harsh Environments at Glenn Research Center

NASA Technical Reports Server (NTRS)

Zeller, Mary V.; Lei, Jih-Fen

2002-01-01

The Instrumentation and Controls Division is responsible for planning, conducting and directing basic and applied research on advanced instrumentation and controls technologies for aerospace propulsion and power applications. The Division's advanced research in harsh environment sensors, high temperature high power electronics, MEMS (microelectromechanical systems), nanotechnology, high data rate optical instrumentation, active and intelligent controls, and health monitoring and management will enable self-feeling, self-thinking, self-reconfiguring and self-healing Aerospace Propulsion Systems. These research areas address Agency challenges to deliver aerospace systems with reduced size and weight, and increased functionality and intelligence for future NASA missions in advanced aeronautics, economical space transportation, and pioneering space exploration. The Division also actively supports educational and technology transfer activities aimed at benefiting all humankind.

Evanescent field refractometry in planar optical fiber.

PubMed

Holmes, Christopher; Jantzen, Alexander; Gray, Alan C; Gow, Paul C; Carpenter, Lewis G; Bannerman, Rex H S; Gates, James C; Smith, Peter G R

2018-02-15

This Letter demonstrates a refractometer in integrated optical fiber, a new optical platform that planarizes fiber using flame hydrolysis deposition (FHD). The unique advantage of the technology is survivability in harsh environments. The platform is mechanically robust, and can survive elevated temperatures approaching 1000°C and exposure to common solvents, including acetone, gasoline, and methanol. For the demonstrated refractometer, fabrication was achieved through wet etching an SMF-28 fiber to a diameter of 8 μm before FHD planarization. An external refractive index was monitored using fiber Bragg gratings (FBGs), written into the core of the planarized fiber. A direct comparison to alternative FBG refractometers is made, for which the developed platform is shown to have comparable sensitivity, with the added advantage of survivability in harsh environments.

Resistive Oxygen Gas Sensors for Harsh Environments

PubMed Central

Moos, Ralf; Izu, Noriya; Rettig, Frank; Reiß, Sebastian; Shin, Woosuck; Matsubara, Ichiro

2011-01-01

Resistive oxygen sensors are an inexpensive alternative to the classical potentiometric zirconia oxygen sensor, especially for use in harsh environments and at temperatures of several hundred °C or even higher. This device-oriented paper gives a historical overview on the development of these sensor materials. It focuses especially on approaches to obtain a temperature independent behavior. It is shown that although in the past 40 years there have always been several research groups working concurrently with resistive oxygen sensors, novel ideas continue to emerge today with respect to improvements of the sensor response time, the temperature dependence, the long-term stability or the manufacture of the devices themselves using novel techniques for the sensitive films. Materials that are the focus of this review are metal oxides; especially titania, titanates, and ceria-based formulations. PMID:22163805

Hybrid AlGaN-SiC Avalanche Photodiode for Deep-UV Photon Detection

NASA Technical Reports Server (NTRS)

Aslam, Shahid; Herrero, Federico A.; Sigwarth, John; Goldsman, Neil; Akturk, Akin

2010-01-01

The proposed device is capable of counting ultraviolet (UV) photons, is compatible for inclusion into space instruments, and has applications as deep- UV detectors for calibration systems, curing systems, and crack detection. The device is based on a Separate Absorption and Charge Multiplication (SACM) structure. It is based on aluminum gallium nitride (AlGaN) absorber on a silicon carbide APD (avalanche photodiode). The AlGaN layer absorbs incident UV photons and injects photogenerated carriers into an underlying SiC APD that is operated in Geiger mode and provides current multiplication via avalanche breakdown. The solid-state detector is capable of sensing 100-to-365-nanometer wavelength radiation at a flux level as low as 6 photons/pixel/s. Advantages include, visible-light blindness, operation in harsh environments (e.g., high temperatures), deep-UV detection response, high gain, and Geiger mode operation at low voltage. Furthermore, the device can also be designed in array formats, e.g., linear arrays or 2D arrays (micropixels inside a superpixel).

A Track Initiation Method for the Underwater Target Tracking Environment

NASA Astrophysics Data System (ADS)

Li, Dong-dong; Lin, Yang; Zhang, Yao

2018-04-01

A novel efficient track initiation method is proposed for the harsh underwater target tracking environment (heavy clutter and large measurement errors): track splitting, evaluating, pruning and merging method (TSEPM). Track initiation demands that the method should determine the existence and initial state of a target quickly and correctly. Heavy clutter and large measurement errors certainly pose additional difficulties and challenges, which deteriorate and complicate the track initiation in the harsh underwater target tracking environment. There are three primary shortcomings for the current track initiation methods to initialize a target: (a) they cannot eliminate the turbulences of clutter effectively; (b) there may be a high false alarm probability and low detection probability of a track; (c) they cannot estimate the initial state for a new confirmed track correctly. Based on the multiple hypotheses tracking principle and modified logic-based track initiation method, in order to increase the detection probability of a track, track splitting creates a large number of tracks which include the true track originated from the target. And in order to decrease the false alarm probability, based on the evaluation mechanism, track pruning and track merging are proposed to reduce the false tracks. TSEPM method can deal with the track initiation problems derived from heavy clutter and large measurement errors, determine the target's existence and estimate its initial state with the least squares method. What's more, our method is fully automatic and does not require any kind manual input for initializing and tuning any parameter. Simulation results indicate that our new method improves significantly the performance of the track initiation in the harsh underwater target tracking environment.

Visitor’s Guide to Oliktok Point Atmospheric Radiation Measurement Climate Research Facility, North Slope of Alaska

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

Desilets, Darin; Helsel, Fred M.; Bendure, Al O.

2016-04-01

The importance of Oliktok Point, Alaska, as a focal point for climate research in the Arctic continues to grow with the addition of a U.S. Department of Energy (DOE) Atmospheric Radiation Monitoring (ARM) Climate Research Facility Mobile Facility (AMF) and the expansion of infrastructure to support airborne measurements. The site hosts a suite of instruments for making multi-year, high-fidelity atmospheric measurements; serves as a base of operations for field campaigns; and contains the only Restricted Airspace and Warning Area in the U.S. Arctic, which enables the use of unmanned aircraft systems. The use of this site by climate researchers involvesmore » several considerations, including its remoteness, harsh climate, and location amid the North Slope oilfields. This guide is intended to help visitors to Oliktok Point navigate this unique physical and administrative environment, and thereby facilitate safe and productive operations.« less

Protecting Juno Electronics from Radiation

NASA Image and Video Library

2010-07-12

Technicians installed the special radiation vault for NASA Juno spacecraft on the propulsion module. The radiation vault has titanium walls to protect the spacecraft electronic brain and heart from Jupiter harsh radiation environment.

Electroplate Short Mix

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

None

2017-06-19

Modifying the surface chemistry of materials by aluminization can protect vulnerable materials from corroding in harsh environments. The industry deals with corrosion issues is to regularly inspect components and replace them with corrosion resistant components.

Embedded Active Fiber Optic Sensing Network for Structural Health Monitoring in Harsh Environments

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

Wang, Anbo

This report summarizes technical progress on the program “Embedded Active Fiber Optic Sensing Network for Structural Health Monitoring in Harsh Environments” funded by the National Energy Technology Laboratory of the U.S. Department of Energy, and performed by the Center for Photonics Technology at Virginia Tech. The objective of this project is to develop a first-of-a-kind technology for remote fiber optic generation and detection of acoustic waves for structural health monitoring in harsh environments. During the project period, which is from April 1, 2013 to Septemeber 30, 2016, three different acoustic generation mechanisms were studied in detail for their applications inmore » building a fiber optic acoustic generation unit (AGU), including laser induced plasma breakdown (LIP), Erbium-doped fiber laser absorption, and metal laser absorption. By comparing the performance of the AGUs designed based on these three mechanisms and analyzing the experimental results with simulations, the metal laser absorption method was selected to build a complete fiber optic structure health monitoring (FO-SHM) system for the proposed high temperature multi-parameter structure health monitoring application. Based on the simulation of elastic wave propagation and fiber Bragg grating acoustic pulse detection, an FO-SHM element together with a completed interrogation system were designed and built. This system was first tested on an aluminum piece in the low-temperature range and successfully demonstrated its capability of multi-parameter monitoring and multi-point sensing. In the later stages of the project, the research was focused on improving the surface attachment design and preparing the FO-SHM element for high temperature environment tests. After several upgrades to the surface attachment methods, the FO-SHM element was able to work reliably up to 600oC when attached to P91 pipes, which are the target material of this project. In the final stage of this project, this FO-SHM sensing system was tested in the simulated harsh environment for its multi-parameter monitoring performance and high-temperature survivability.« less

6H-SiC Transistor Integrated Circuits Demonstrating Prolonged Operation at 500 C

NASA Technical Reports Server (NTRS)

Neudeck, Philip G.; Spry, David J.; Chen, Liang-Yu; Chang, Carl W.; Beheim, Glenn M.; Okojie, Robert S.; Evans, Laura J.; Meredith, Roger; Ferrier, Terry; Krasowski, Michael J.;

75 FR 56562 - Proposed Information Collection Request Submitted for Public Comment and Recommendations...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-09-16

... safe and healthful working environment. A well planned mine ventilation system is necessary to assure a fresh air supply to miners at all working places, to control the amounts of harmful airborne... present harsh and hostile working environments. The ventilation system is the most vital life support...

Phytoremediation and phytomining: Using plants to remediate contaminated or mineralized environments

USDA-ARS?s Scientific Manuscript database

One type of harsh environment for plants is metal and metalloid contaminated or mineralized soils which exist in most countries due to geological formations or to the history of mining and smelting. Depending on soil pH and fertility, metal-rich soils may be barren and eroding into wider areas. Some...

Inspecting Juno Radiation Vault

NASA Image and Video Library

2010-07-12

A technician inspects the special radiation vault being installed atop the propulsion module of NASA Juno spacecraft; the vault has titanium walls to protect the spacecraft electronic brain and heart from Jupiter harsh radiation environment.

Study on ammonia slip detection in the harsh combustion environments using diode laser spectroscopy

NASA Astrophysics Data System (ADS)

You, Kun; Zhang, Yu-jun; Li, Hong-bin; He, Yin; Gao, Yan-wei; Wang, Li-ming; Liu, Wen-qing

2016-10-01

The emissions of NOX from Cement plant or Coal-fired power plant have serious pollution to the environment. In recent years, Selective Catalytic Reduction (SCR) is an effective means of reducing the emissions of NOX by injecting ammonia into the combustion flue gas, which ideally reacts with the NOX to produce harmless components (H2O and N2). The efficiency of SCR is determined by monitoring the ammonia slip of the flue exhaust outlet, excess ammonia injection can cause ammonia slip, which not only destroy the plant, but also increase the operating costs. In addition, ammonia is also pollution gases as NOX. The flue gas at the measurement point is high temperature, vibrate and high particle density processes in Cement plant primarily, such harsh conditions coupled with the highly reactive nature of ammonia, so it is difficult to reliable extractive low level analysis. The paper describes an in-situ Tunable Diode Laser analyzer for measuring ammonia slip in the combustion flue gas after SCR in Cement Plant or Coal-fired power plant. A correlation filtering algorithm is developed to select high-quality spectral absorption signal, which improve the accuracy of concentration inversion of analyzer. The paper also includes field test data on an actual Cement plant all day, and we compare the ammonia slip and NOX emissions of flue gas during actual production process, the results indicate that the measured values of the ammonia slip and NOX emissions present a good correlation and comply with the principle of SCR.

Grazing incidence extreme ultraviolet spectrometer fielded with time resolution in a hostile z-pinch environment.

PubMed

Williamson, K M; Kantsyrev, V L; Safronova, A S; Wilcox, P G; Cline, W; Batie, S; LeGalloudec, B; Nalajala, V; Astanovitsky, A

2011-09-01

This recently developed diagnostic was designed to allow for time-gated spectroscopic study of the EUV radiation (4 nm < λ < 15 nm) present during harsh wire array z-pinch implosions. The spectrometer utilizes a 25 μm slit, an array of 3 spherical blazed gratings at grazing incidence, and a microchannel plate (MCP) detector placed in an off-Rowland position. Each grating is positioned such that its diffracted radiation is cast over two of the six total independently timed frames of the MCP. The off-Rowland configuration allows for a much greater spectral density on the imaging plate but only focuses at one wavelength per grating. The focal wavelengths are chosen for their diagnostic significance. Testing was conducted at the Zebra pulsed-power generator (1 MA, 100 ns risetime) at the University of Nevada, Reno on a series of wire array z-pinch loads. Within this harsh z-pinch environment, radiation yields routinely exceed 20 kJ in the EUV and soft x-ray. There are also strong mechanical shocks, high velocity debris, sudden vacuum changes during operation, energic ion beams, and hard x-ray radiation in excess of 50 keV. The spectra obtained from the precursor plasma of an Al double planar wire array contained lines of Al IX and AlX ions indicating a temperature near 60 eV during precursor formation. Detailed results will be presented showing the fielding specifications and the techniques used to extract important plasma parameters using this spectrometer. © 2011 American Institute of Physics

Impact of annealing temperature on the mechanical and electrical properties of sputtered aluminum nitride thin films

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

Gillinger, M.; Schneider, M.; Bittner, A.

2015-02-14

Aluminium nitride (AlN) is a promising material for challenging sensor applications such as process monitoring in harsh environments (e.g., turbine exhaust), due to its piezoelectric properties, its high temperature stability and good thermal match to silicon. Basically, the operational temperature of piezoelectric materials is limited by the increase of the leakage current as well as by enhanced diffusion effects in the material at elevated temperatures. This work focuses on the characterization of aluminum nitride thin films after post deposition annealings up to temperatures of 1000 °C in harsh environments. For this purpose, thin film samples were temperature loaded for 2 hmore » in pure nitrogen and oxygen gas atmospheres and characterized with respect to the film stress and the leakage current behaviour. The X-ray diffraction results show that AlN thin films are chemically stable in oxygen atmospheres for 2 h at annealing temperatures of up to 900 °C. At 1000 °C, a 100 nm thick AlN layer oxidizes completely. For nitrogen, the layer is stable up to 1000 °C. The activation energy of the samples was determined from leakage current measurements at different sample temperatures, in the range between 25 and 300 °C. Up to an annealing temperature of 700 °C, the leakage current in the thin film is dominated by Poole-Frenkel behavior, while at higher annealing temperatures, a mixture of different leakage current mechanisms is observed.« less

Testing of a Wireless Sensor System for Instrumented Thermal Protection Systems

NASA Technical Reports Server (NTRS)

Kummer, Allen T.; Weir, Erik D.; Morris, Trey J.; Friedenberger, Corey W.; Singh, Aseem; Capuro, Robert M.; Bilen, Sven G.; Fu, Johnny; Swanson, Gregory T.; Hash, David B.

2011-01-01

Funded by NASA's Constellation Universities Institutes Project (CUIP), we have been developing and testing a system to wirelessly power and collect data from sensors on space platforms in general and, in particular, the harsh environment of spacecraft re-entry. The elimination of wires and associated failures such as chafing, sparking, ageing, and connector issues can increase reliability and design flexibility while reducing costs. These factors present an appealing case for the pursuit of wireless solutions for harsh environments, particularly for their use in space and on spacecraft. We have designed and built a prototype wireless sensor system. The system, with capabilities similar to that of a wired sensor system, was tested in NASA Ames Research Center s Aerodynamic Heating Facility and Interaction Heating Facility. This paper discusses the overall development effort, testing results, as well as future directions.

Multichip module technology for automotive application

NASA Astrophysics Data System (ADS)

Johnson, R. Wayne; Evans, John L.; Bosley, Larry

1995-01-01

Advancements in multichip module technology are creating design freedoms previously unavailable to design engineers. These advancements are opening new markets for laminate based multichip module products. In particular, material improvements in laminate printed wiring boards are allowing multichip module technology to meet more stringent environmental conditions. In addition, improvements in encapsulants and adhesives are enhancing the capabilities of multichip module technology to meet harsh environment. Furthermore, improvements in manufacturing techniques are providing the reliability improvements necessary for use in high quality electronic systems. These advances are making multichip module technology viable for high volume, harsh environment applications like under-the-hood automotive electronics. This paper will provide a brief review of multichip module technology, a discussion of specific research activities with Chrysler for use of multichip modules in automotive engine controllers and finally a discussion of prototype multichip modules fabricated and tested.

A new class of boron nitride fibers with tunable properties by combining an electrospinning process and the polymer-derived ceramics route

NASA Astrophysics Data System (ADS)

Salles, Vincent; Bernard, Samuel; Brioude, Arnaud; Cornu, David; Miele, Philippe

2010-02-01

Novel boron nitride (BN) fibers have been developed with diameters ranging from the nano- to microscale by thermal conversion of as-electrospun fibers from polyacrylonitrile and poly[B-(methylamino)borazine] blend solutions. Such a new class of ceramic fibers is seen as potential candidate for thermal management applications and filtration systems in harsh environments.Novel boron nitride (BN) fibers have been developed with diameters ranging from the nano- to microscale by thermal conversion of as-electrospun fibers from polyacrylonitrile and poly[B-(methylamino)borazine] blend solutions. Such a new class of ceramic fibers is seen as potential candidate for thermal management applications and filtration systems in harsh environments. Electronic supplementary information (ESI) available: Experimental details and EDX results. See DOI: 10.1039/b9nr00185a

Ultra-thin nanocrystalline diamond membranes as pressure sensors for harsh environments

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

Janssens, S. D., E-mail: stoffel.d.janssens@gmail.com; Haenen, K., E-mail: ken.haenen@uhasselt.be; IMOMEC, IMEC vzw, Wetenschapspark 1, B-3590 Diepenbeek

2014-02-17

Glass and diamond are suitable materials for harsh environments. Here, a procedure for fabricating ultra-thin nanocrystalline diamond membranes on glass, acting as an electrically insulating substrate, is presented. In order to investigate the pressure sensing properties of such membranes, a circular, highly conductive boron-doped nanocrystalline diamond membrane with a resistivity of 38 mΩ cm, a thickness of 150 nm, and a diameter of 555 μm is fabricated in the middle of a Hall bar structure. During the application of a positive differential pressure under the membrane (0–0.7 bar), four point piezoresistive effect measurements are performed. From these measurements, it can be concluded that the resistancemore » response of the membrane, as a function of differential pressure, is highly linear and sensitive.« less

Development and applications of ruggedized VIS/NIR spectrometer system for oilfield wellbores

NASA Astrophysics Data System (ADS)

Fujisawa, Go; Yamate, Tsutomu

2013-12-01

The development and applications of a ruggedized visible to near-infrared (VIS/NIR) spectrometer system capable of measuring fluid spectra in oilfield wellbores are presented. Real-time assessment of formation fluid properties penetrated by an oilfield wellbore is critically important for oilfield operating companies to make informed decisions to optimize the development plan of the well and hydrocarbon reservoir. A ruggedized VIS/NIR spectrometer was designed and built to measure and analyze hydrocarbon spectra reliably under the harsh conditions of the oilfield wellbore environment, including temperature up to 175 °C, pressure up to 170 MPa, and severe mechanical shocks and vibrations. The accuracy of hydrocarbon group composition analysis was compared well with gas chromatography results in the laboratory.

Autonomous sensor particle for parameter tracking in large vessels

NASA Astrophysics Data System (ADS)

Thiele, Sebastian; Da Silva, Marco Jose; Hampel, Uwe

2010-08-01

A self-powered and neutrally buoyant sensor particle has been developed for the long-term measurement of spatially distributed process parameters in the chemically harsh environments of large vessels. One intended application is the measurement of flow parameters in stirred fermentation biogas reactors. The prototype sensor particle is a robust and neutrally buoyant capsule, which allows free movement with the flow. It contains measurement devices that log the temperature, absolute pressure (immersion depth) and 3D-acceleration data. A careful calibration including an uncertainty analysis has been performed. Furthermore, autonomous operation of the developed prototype was successfully proven in a flow experiment in a stirred reactor model. It showed that the sensor particle is feasible for future application in fermentation reactors and other industrial processes.

Segmented assimilation theory and the life model: an integrated approach to understanding immigrants and their children.

PubMed

Piedra, Lissette M; Engstrom, David W

2009-07-01

The life model offers social workers a promising framework to use in assisting immigrant families. However, the complexities of adaptation to a new country may make it difficult for social workers to operate from a purely ecological approach. The authors use segmented assimilation theory to better account for the specificities of the immigrant experience. They argue that by adding concepts from segmented assimilation theory to the life model, social workers can better understand the environmental stressors that increase the vulnerabilities of immigrants to the potentially harsh experience of adapting to a new country. With these concepts, social workers who work with immigrant families will be better positioned to achieve their central goal: enhancing person and environment fit.

Ultrathin gas permeable oxide membranes for chemical sensing: Nanoporous Ta 2O 5 test study

DOE PAGES

Imbault, Alexander; Wang, Yue; Kruse, Peter; ...

2015-09-25

Conductometric gas sensors made of gas permeable metal oxide ultrathin membranes can combine the functions of a selective filter, preconcentrator, and sensing element and thus can be particularly promising for the active sampling of diluted analytes. Here we report a case study of the electron transport and gas sensing properties of such a membrane made of nanoporous Ta 2O 5. These membranes demonstrated a noticeable chemical sensitivity toward ammonia, ethanol, and acetone at high temperatures above 400 °C. Furthermore, different from traditional thin films, such gas permeable, ultrathin gas sensing elements can be made suspended enabling advanced architectures of ultrasensitivemore » analytical systems operating at high temperatures and in harsh environments.« less

Multi-energy x-ray imaging and sensing for diagnostic and control of the burning plasma.

PubMed

Stutman, D; Tritz, K; Finkenthal, M

2012-10-01

New diagnostic and sensor designs are needed for future burning plasma (BP) fusion experiments, having good space and time resolution and capable of prolonged operation in the harsh BP environment. We evaluate the potential of multi-energy x-ray imaging with filtered detector arrays for BP diagnostic and control. Experimental studies show that this simple and robust technique enables measuring with good accuracy, speed, and spatial resolution the T(e) profile, impurity content, and MHD activity in a tokamak. Applied to the BP this diagnostic could also serve for non-magnetic sensing of the plasma position, centroid, ELM, and RWM instability. BP compatible x-ray sensors are proposed using "optical array" or "bi-cell" detectors.

An automated calibration laboratory - Requirements and design approach

NASA Technical Reports Server (NTRS)

O'Neil-Rood, Nora; Glover, Richard D.

1990-01-01

NASA's Dryden Flight Research Facility (Ames-Dryden), operates a diverse fleet of research aircraft which are heavily instrumented to provide both real time data for in-flight monitoring and recorded data for postflight analysis. Ames-Dryden's existing automated calibration (AUTOCAL) laboratory is a computerized facility which tests aircraft sensors to certify accuracy for anticipated harsh flight environments. Recently, a major AUTOCAL lab upgrade was initiated; the goal of this modernization is to enhance productivity and improve configuration management for both software and test data. The new system will have multiple testing stations employing distributed processing linked by a local area network to a centralized database. The baseline requirements for the new AUTOCAL lab and the design approach being taken for its mechanization are described.

Habitability in the Local Universe

NASA Astrophysics Data System (ADS)

Mason, Paul A.

2017-01-01

Long term habitability on the surface of planets has as a prerequisite a minimum availability of elements to build rocky planets, their atmospheres, and for life sustaining water. They must be within the habitable zone and avoid circumstances that cause them to lose their atmospheres and water. However, many astrophysical sources are hazardous to life on the surfaces of planets. Planets in harsh environments may require strong magnetic fields to protect their biospheres from high energy particles from the host star(s). Planets in harsh environments may additionally require a strong astrosphere to be sufficiently able to deflect galactic cosmic-rays. Supernovae (SNe) play a central role in the habitability of planets in the disks of star forming galaxies. Currently, the SNe rate maintains a relativistic galactic wind shielding planets in the disk from extragalactic cosmic rays. However, if the density of SNe in the disk of the galaxy were significantly higher, as it was 6-8 GYA, the frequency of nearby catastrophic events and often prolonged harsh environment may have strongly constrained life in the early history of the Milky Way. Active galactic nuclei (AGN) may remain quiescent for hundreds of millions of years only to activate for some time due extraordinary accretion episode due to for instance a galactic merger. The starburst galaxy M82 is currently undergoing a merger, probably strongly compromising habitability within that galaxy. The giant elliptical M87 resides in the center of the Virgo supercluster and has probably consumed many such spiral galaxies. We show that super-Eddington accretion onto the supermassive black hole in M87, even for a short while, could compromise the habitability for a large portion of the central supercluster. We discuss environments where these effects may be mitigated.

Coherent beam combining performance in harsh environment

NASA Astrophysics Data System (ADS)

Lombard, L.; Canat, G.; Durecu, A.; Bourdon, P.

2014-03-01

Coherent beam combining (CBC) is a promising solution for high power directed energy weapons. We investigate several particular issues for this application: First, we study the evolution of phase noise spectrum for increasing pump power in 100 W MOPFA. The main variations in the spectrum are located in the low frequency region corresponding to thermal transfer between the fiber core heated by the pump absorption and the fiber environment. The phase noise root mean square evolves linearly with the pump power. Noise spectrum is not shifted to higher frequencies. Second, we investigate the influence of fiber packaging and amplifier packaging on the phase noise and estimate the LOCSET controller bandwidth (BW) requirement in each case. Results show large variation of BW depending on the packaging, and not on the power. Then, we investigate the performances of CBC in harsh environment. For this purpose, we implement CBC of a 20-W fiber amplifier and a passive fiber using the LOCSET technique and simulate harsh environment by applying strong vibrations with a hammering drill on the optical table. The applied vibration spectrum ranges from 1 Hz to ~10 kHz with a standard deviation of 9 m/s2. CBC of the amplifier output and the passive fiber output is performed on a second table, isolated from vibrations. Measurements of the phase difference between both outputs and of the applied vibrations are simultaneously performed. Residual phase error of λ/40 (i.e. > 99 % CBC efficiency) is achieved under strong vibrations at 20 W. The -3 dB bandwidth of the LOCSET controller has been measured to be ~4.5 kHz. Results are in agreement with simulations.

Advanced Multifunctional MMOD Shield: Radiation Shielding Assessment

NASA Technical Reports Server (NTRS)

Rojdev, Kristina; Christiansen, Eric

2013-01-01

Deep space missions must contend with a harsh radiation environment Impacts to crew and electronics. Need to invest in multifunctionality for spacecraft optimization. MMOD shield. Goals: Increase radiation mitigation potential. Retain overall MMOD shielding performance.

Differentially expressed drought-responsive genes in Malus sieversii roots may contribute to this species' adaptation to arid environments

USDA-ARS?s Scientific Manuscript database

Understanding naturally evolved adaptation to arid climates may be a key factor in developing crops that can thrive during extreme climate fluctuations. Malus sieversii (Ledeb.) M. Roem. is a wild apple species that has adapted to harsh environments in Kazakhstan, including extreme cold and dry reg...

78 FR 51749 - Proposed Information Collection; Ventilation Plan and Main Fan Maintenance Record (Pertains to...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-08-21

... maintaining a safe and healthful working environment. A well planned mine ventilation system is necessary to assure a fresh air supply to miners at all working places, to control the amounts of harmful airborne... usually present harsh and hostile working environments. The ventilation system is the most vital life...

All Eggs Are Not Equal: The Maternal Environment Affects Progeny Reproduction and Developmental Fate in Caenorhabditis elegans

PubMed Central

Harvey, Simon C.; Orbidans, Helen E.

2011-01-01

Background Maternal effects on progeny traits are common and these can profoundly alter progeny life history. Maternal effects can be adaptive, representing attempts to appropriately match offspring phenotype to the expected environment and are often mediated via trade-offs between progeny number and quality. Here we have investigated the effect of maternal food availability on progeny life history in the free-living nematode Caenorhabditis elegans. Methodology/Principal Findings The maternal environment affects both reproductive traits and progeny development. Comparisons of the progeny of worms from high and low maternal food environments indicates that low maternal food availability reduces progeny reproduction in good environments, increases progeny reproduction in poor environments and decreases the likelihood that progeny will develop as dauer larvae. These analyses also indicate that the effects on progeny are not a simple consequence of changes in maternal body size, but are associated with an increase in the size of eggs produced by worms at low maternal food availabilities. Conclusions/Significance These results indicate that the maternal environment affects both progeny reproduction and development in C. elegans and therefore that all progeny are not equal. The observed effects are consistent with changes to egg provisioning, which are beneficial in harsh environments, and of changes to progeny development, which are beneficial in harsh environments and detrimental in benign environments. These changes in progeny life history suggest that mothers in poor quality environments may be producing larger eggs that are better suited to poor conditions. PMID:21991370

Making sense of Arctic maritime traffic using the Polar Operational Limits Assessment Risk Indexing System (POLARIS)

NASA Astrophysics Data System (ADS)

Stoddard, M. A.; Etienne, L.; Fournier, M.; Pelot, R.; Beveridge, L.

2016-04-01

Maritime traffic volume in the Arctic is growing for several reasons: climate change is resulting in less ice in extent, duration, and thickness; economic drivers are inducing growth in resource extraction traffic, community size (affecting resupply) and adventure tourism. This dynamic situation, coupled with harsh weather, variable operating conditions, remoteness, and lack of straightforward emergency response options, demand robust risk management processes. The requirements for risk management for polar ship operations are specified in the new International Maritime Organization (IMO) International Code for Ships Operating in Polar Waters (Polar Code). The goal of the Polar Code is to provide for safe ship operations and protection of the polar environment by addressing the risk present in polar waters. Risk management is supported by evidence-based models, including threat identification (types and frequency of hazards), exposure levels, and receptor characterization. Most of the information used to perform risk management in polar waters is attained in-situ, but increasingly is being augmented with open-access remote sensing information. In this paper we focus on the use of open-access historical ice charts as an integral part of northern navigation, especially for route planning and evaluation.

An Investigation of Catastrophic Failure in Solid-State Lamps Exposed to Harsh Environment Operational Conditions

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

Lall, Pradeep; Sakalaukus, Peter; Davis, Lynn

2015-07-06

Today’s lighting technology is steadily becoming more energy efficient and less toxic to the environment since the passing of the Energy Independence and Security Act of 2007 (EISA) [1]. EISA has mandated a higher energy efficiency standard for lighting products and the phase out of the common incandescent lamp. This has led lighting manufacturers to pursue solid-state lighting (SSL) technologies for consumer lighting applications. However, two major roadblocks are hindering the transition process to SSL lamps: cost and quality. In order to cut cost, manufactures are moving towards cheaper packaging materials and a variety of package architecture construction techniques whichmore » may potentially erode the quality of the lamp and reduce its survivability in everyday applications. Typically, SSL lamps are given product lifetimes of over twenty years based off of the IES TM-21-11 lighting standard which does not include moisture effects or large operational temperatures [2]. A group of recently released off-the-shelf lamps have undergone a steady-state temperature humidity bias life test of 85°C/85%RH (85/85) to investigate the reliability in harsh environment applications. The lack of accelerated test methods for lamps to assess reliability prior to introduction into the marketplace does not exist in literature. There is a need for SSL physics based models for the assessment and prediction of a lamp’s lifetime which is being spearheaded by the DOE [3]. In order to be fully accepted in the marketplace, SSL lamps must be able to perform similarly to incandescent lamps in these environments, as well as live up to the lifetime claims of manufacturers. A lamp’s package architecture must be designed with performance factors in mind, as well as address some of the known and published package related failure mechanisms, such as carbonization of the encapsulant material, delamination, encapsulant yellowing, lens cracking, and phosphor thermal quenching [4]. Each failure mechanism produces the similar failure mode of lumen degradation predominately due to two contributing factors: high junction temperature and moisture ingress. The current state-of-the-art has focused on individual areas of the lamp, such as the LED chip, substrate material, electrical driver design and thermal management techniques. [5] – [16] Looking at the lamp as a whole is a novel approach and has not been seen before in literature. This work followed the JEDEC standard JESD22-A101C of 85/85 with a one hour interval of applied voltage followed by a one hour interval of no applied voltage [17]. This test was performed continuously for each SSL lamp until it became nonoperational, i.e. did not turn on. Periodically, photometric measurements were taken following the IES LM-79-08 standard at room temperature using an integrating sphere, a spectrometer, and lighting software. The overall health of the SSL lamps was assed using the relative luminous flux (RLF), correlated color temperature (CCT) and the color difference (Δu'v') using the Euclidean distance of the CIE 1976 color space coordinates. Finally, a Weibull analysis was completed to compare the characteristic lifetime of the SSL lamp to the actual rated lifetime. An important result from this work shows that the rated lifetime does not come close to the actual lifetime when the SSL lamps are used in a harsh humid environment which is fairly common in outdoor applications across the U.S. Also, the photometric results are presented for the entire lifetime of each SSL lamp under test.« less

Embedded infrared fiber-optic sensor for thermometry in a high temperature/pressure environment

NASA Astrophysics Data System (ADS)

Yoo, Wook Jae; Jang, Kyoung Won; Moon, Jinsoo; Han, Ki-Tek; Jeon, Dayeong; Lee, Bongsoo; Park, Byung Gi

2012-11-01

In this study, we developed an embedded infrared fiber-optic temperature sensor for thermometry in high temperature/pressure and water-chemistry environments by using two identical silver-halide optical fibers. The performance of the fabricated temperature sensor was assessed in an autoclave filled with an aqueous coolant solution containing boric acid and lithium hydroxide. We carried out real-time monitoring of the infrared radiation emitted from the signal and reference probes for various temperatures over a temperature range from 95 to 225 °C. In order to decide the temperature of the synthetic coolant solution, we measured the difference between the infrared radiation emitted from the two temperature-sensing probes. Thermometry with the proposed sensor is immune to any changes in the physical conditions and the emissivity of the heat source. From the experimental results, the embedded infrared fiber-optic temperature sensor can withstand, and normally operate in a high temperature/pressure test loop system corresponding to the coolant system used for nuclear power plant simulation. We expect that the proposed sensor can be developed to accurately monitor temperatures in harsh environments.

Paracetamol in the environment and its degradation by microorganisms.

PubMed

Wu, Shijin; Zhang, Lili; Chen, Jianmeng

2012-11-01

Paracetamol (4'-hydroxyacetanilide, N-acetyl-p-aminophenol, acetaminophen, and paracetamol) is a widely used over-the-counter analgesic and antipyretic drug. Paracetamol and structural analogs are ubiquitous in the natural environment and easily accumulate in aquatic environment, which have been detected in surface waters, wastewater, and drinking water throughout the world. Paracetamol wastewater is mainly treated by chemical oxidation processes. Although these chemical methods may be available for treating these pollutants, the harsh reaction conditions, the generation of secondary pollutants, and the high operational cost associated with these methods have often made them not a desirable choice. Biodegradation of paracetamol is being considered as an environmentally friendly and low-cost option. The goal of this review is to provide an outline of the current knowledge of biodegradation of paracetamol in the occurrence, degrading bacteria, and proposed metabolic/biodegrading pathways, enzymes and possible intermediates. The comprehensive understanding of the metabolic pathways and enzyme systems involved in the utilization of paracetamol means will be helpful for optimizing and allowing rational design of biodegradation systems for paracetamol-contaminated wastewater.

Perovskite nickelates as electric-field sensors in salt water

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

Zhang, Zhen; Schwanz, Derek; Narayanan, Badri

Designing materials to function in harsh environments, such as conductive aqueous media, is a problem of broad interest to a range of technologies, including energy, ocean monitoring and biological applications(1-4). The main challenge is to retain the stability and morphology of the material as it interacts dynamically with the surrounding environment. Materials that respond to mild stimuli through collective phase transitions and amplify signals could open up new avenues for sensing. Here we present the discovery of an electric-field-driven, water-mediated reversible phase change in a perovskite-structured nickelate, SmNiO35-7. This prototypical strongly correlated quantum material is stable in salt water, doesmore » not corrode, and allows exchange of protons with the surrounding water at ambient temperature, with the concurrent modification in electrical resistance and optical properties being capable of multi-modal readout. Besides operating both as thermistors and pH sensors, devices made of this material can detect sub-volt electric potentials in salt water. We postulate that such devices could be used in oceanic environments for monitoring electrical signals from various maritime vessels and sea creatures« less

Perovskite nickelates as electric-field sensors in salt water

NASA Astrophysics Data System (ADS)

Zhang, Zhen; Schwanz, Derek; Narayanan, Badri; Kotiuga, Michele; Dura, Joseph A.; Cherukara, Mathew; Zhou, Hua; Freeland, John W.; Li, Jiarui; Sutarto, Ronny; He, Feizhou; Wu, Chongzhao; Zhu, Jiaxin; Sun, Yifei; Ramadoss, Koushik; Nonnenmann, Stephen S.; Yu, Nanfang; Comin, Riccardo; Rabe, Karin M.; Sankaranarayanan, Subramanian K. R. S.; Ramanathan, Shriram

2018-01-01

Designing materials to function in harsh environments, such as conductive aqueous media, is a problem of broad interest to a range of technologies, including energy, ocean monitoring and biological applications. The main challenge is to retain the stability and morphology of the material as it interacts dynamically with the surrounding environment. Materials that respond to mild stimuli through collective phase transitions and amplify signals could open up new avenues for sensing. Here we present the discovery of an electric-field-driven, water-mediated reversible phase change in a perovskite-structured nickelate, SmNiO3. This prototypical strongly correlated quantum material is stable in salt water, does not corrode, and allows exchange of protons with the surrounding water at ambient temperature, with the concurrent modification in electrical resistance and optical properties being capable of multi-modal readout. Besides operating both as thermistors and pH sensors, devices made of this material can detect sub-volt electric potentials in salt water. We postulate that such devices could be used in oceanic environments for monitoring electrical signals from various maritime vessels and sea creatures.

Tough times call for bigger brains

PubMed Central

Pravosudov, Vladimir V

2009-01-01

Memory is crucial for survival in many animals. Spatial memory in particular is important for food-caching species and may be influenced by selective pressures such as climate. The influence of climate on memory may be facilitated through the hippocampus (Hp), the part of the brain responsible in part for spatial memory. In a recent paper, we conducted the first large-scale test of the relationship between memory, the climate and the brain in a single food-caching species, the black-capped chickadee (Poecile atricapillus). We found that birds from more harsh northern climates had significantly larger hippocampal volumes and more neurons than those from more mild southern latitudes. This work suggests that environmental pressures are capable of influencing specific brain regions, which may result in enhanced memory, and hence survival, in harsh climates. This work gives us a better understanding of how the brain responds to different environments and how animals can adapt to their environment in general. PMID:19641741

Shock and vibration effects on performance reliability and mechanical integrity of proton exchange membrane fuel cells: A critical review and discussion

NASA Astrophysics Data System (ADS)

Haji Hosseinloo, Ashkan; Ehteshami, Mohsen Mousavi

2017-10-01

Performance reliability and mechanical integrity are the main bottlenecks in mass commercialization of PEMFCs for applications with inherent harsh environment such as automotive and aerospace applications. Imparted shock and vibration to the fuel cell in such applications could bring about numerous issues including clamping torque loosening, gas leakage, increased electrical resistance, and structural damage and breakage. Here, we provide a comprehensive review and critique of the literature focusing on the effects of mechanically harsh environment on PEMFCs, and at the end, we suggest two main future directions in FC technology research that need immediate attention: (i) developing a generic and adequately accurate dynamic model of PEMFCs to assess the dynamic response of FC devices, and (ii) designing effective and robust shock and vibration protection systems based on the developed models in (i).

Battery-free Wireless Sensor Network For Advanced Fossil-Fuel Based Power Generation

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

Yi Jia

2011-02-28

This report summarizes technical progress achieved during the project supported by the Department of Energy under Award Number DE-FG26-07NT4306. The aim of the project was to conduct basic research into battery-free wireless sensing mechanism in order to develop novel wireless sensors and sensor network for physical and chemical parameter monitoring in a harsh environment. Passive wireless sensing platform and five wireless sensors including temperature sensor, pressure sensor, humidity sensor, crack sensor and networked sensors developed and demonstrated in our laboratory setup have achieved the objective for the monitoring of various physical and chemical parameters in a harsh environment through remotemore » power and wireless sensor communication, which is critical to intelligent control of advanced power generation system. This report is organized by the sensors developed as detailed in each progress report.« less

Simulated Space Environment Effects on a Candidate Solar Sail Material

NASA Technical Reports Server (NTRS)

Kang, Jin Ho; Bryant, Robert G.; Wilkie, W. Keats; Wadsworth, Heather M.; Craven, Paul D.; Nehls, Mary K.; Vaughn, Jason A.

2017-01-01

For long duration missions of solar sail vehicles, the sail material needs to survive the harsh space environment as the degradation of the sail material determines its operational lifetime. Therefore, understanding the effects of the space environment on the sail membrane is essential for mission success. In this study, the effect of simulated space environments of ionizing radiation and thermal aging were investigated. In order to assess some of the potential damage effects on the mechanical, thermal and optical properties of a commercial off the shelf (COTS) polyester solar sail membrane. The solar sail membrane was exposed to high energy electrons [about 70 keV and 10 nA/cm(exp. 2)], and the physical properties were characterized. After about 8.3 Grad dose, the tensile modulus, tensile strength and failure strain of the sail membrane decreased by 20 to 95%. The aluminum reflective layer was damaged and partially delaminated but it did not show any significant change in solar absorbance or thermal emittance. The mechanical properties of a precracked sample, simulating potential impact damage of the sail membrane, as well as thermal aging effects on metallized PEN (polyethylene naphthalate) film, will be discussed.

Simulated Space Environment Effects on a Candidate Solar Sail Material

NASA Technical Reports Server (NTRS)

Kang, Jin Ho; Bryant, Robert G.; Wilkie, W. Keats; Wadsworth, Heather M.; Craven, Paul D.; Nehls, Mary K.; Vaughn, Jason A.

2017-01-01

For long duration missions of solar sails, the sail material needs to survive harsh space environments and the degradation of the sail material controls operational lifetime. Therefore, understanding the effects of the space environment on the sail membrane is essential for mission success. In this study, we investigated the effect of simulated space environment effects of ionizing radiation, thermal aging and simulated potential damage on mechanical, thermal and optical properties of a commercial off the shelf (COTS) polyester solar sail membrane to assess the degradation mechanisms on a feasible solar sail. The solar sail membrane was exposed to high energy electrons (about 70 keV and 10 nA/cm2), and the physical properties were characterized. After about 8.3 Grad dose, the tensile modulus, tensile strength and failure strain of the sail membrane decreased by about 20 95%. The aluminum reflective layer was damaged and partially delaminated but it did not show any significant change in solar absorbance or thermal emittance. The effect on mechanical properties of a pre-cracked sample, simulating potential impact damage of the sail membrane, as well as thermal aging effects on metallized PEN (polyethylene naphthalate) film will be discussed.

Effects on Training Using Illumination in Virtual Environments

NASA Technical Reports Server (NTRS)

Maida, James C.; Novak, M. S. Jennifer; Mueller, Kristian

1999-01-01

Camera based tasks are commonly performed during orbital operations, and orbital lighting conditions, such as high contrast shadowing and glare, are a factor in performance. Computer based training using virtual environments is a common tool used to make and keep CTW members proficient. If computer based training included some of these harsh lighting conditions, would the crew increase their proficiency? The project goal was to determine whether computer based training increases proficiency if one trains for a camera based task using computer generated virtual environments with enhanced lighting conditions such as shadows and glare rather than color shaded computer images normally used in simulators. Previous experiments were conducted using a two degree of freedom docking system. Test subjects had to align a boresight camera using a hand controller with one axis of rotation and one axis of rotation. Two sets of subjects were trained on two computer simulations using computer generated virtual environments, one with lighting, and one without. Results revealed that when subjects were constrained by time and accuracy, those who trained with simulated lighting conditions performed significantly better than those who did not. To reinforce these results for speed and accuracy, the task complexity was increased.

Electronics Demonstrated for Low- Temperature Operation

NASA Technical Reports Server (NTRS)

Patterson, Richard L.; Hammond, Ahmad; Gerber, Scott S.

2000-01-01

The operation of electronic systems at cryogenic temperatures is anticipated for many NASA spacecraft, such as planetary explorers and deep space probes. For example, an unheated interplanetary probe launched to explore the rings of Saturn would experience an average temperature near Saturn of about 183 C. Electronics capable of low-temperature operation in the harsh deep space environment also would help improve circuit performance, increase system efficiency, and reduce payload development and launch costs. An ongoing research and development program on low-temperature electronics at the NASA Glenn Research Center at Lewis Field is focusing on the design of efficient power systems that can survive and exploit the advantages of low-temperature environments. The targeted systems, which are mission driven, include converters, inverters, controls, digital circuits, and special-purpose circuits. Initial development efforts successfully demonstrated the low-temperature operation and cold-restart of several direct-current/direct-current (dc/dc) converters based on different types of circuit design, some with superconducting inductors. The table lists some of these dc/dc converters with their properties, and the photograph shows a high-voltage, high-power dc/dc converter designed for an ion propulsion system for low-temperature operation. The development efforts of advanced electronic systems and the supporting technologies for low-temperature operation are being carried out in-house and through collaboration with other Government agencies, industry, and academia. The Low Temperature Electronics Program supports missions and development programs at NASA s Jet Propulsion Laboratory and Goddard Space Flight Center. The developed technologies will be transferred to commercial end users for applications such as satellite infrared sensors and medical diagnostic equipment.

Development of an Extreme High Temperature n-type Ohmic Contact to Silicon Carbide

NASA Technical Reports Server (NTRS)

Evans, Laura J.; Okojie, Robert S.; Lukco, Dorothy

2011-01-01

We report on the initial demonstration of a tungsten-nickel (75:25 at. %) ohmic contact to silicon carbide (SiC) that performed for up to fifteen hours of heat treatment in argon at 1000 C. The transfer length method (TLM) test structure was used to evaluate the contacts. Samples showed consistent ohmic behavior with specific contact resistance values averaging 5 x 10-4 -cm2. The development of this contact metallization should allow silicon carbide devices to operate more reliably at the present maximum operating temperature of 600 C while potentially extending operations to 1000 C. Introduction Silicon Carbide (SiC) is widely recognized as one of the materials of choice for high temperature, harsh environment sensors and electronics due to its ability to survive and continue normal operation in such environments [1]. Sensors and electronics in SiC have been developed that are capable of operating at temperatures of 600 oC. However operating these devices at the upper reliability temperature threshold increases the potential for early degradation. Therefore, it is important to raise the reliability temperature ceiling higher, which would assure increased device reliability when operated at nominal temperature. There are also instances that require devices to operate and survive for prolonged periods of time above 600 oC [2, 3]. This is specifically needed in the area of hypersonic flight where robust sensors are needed to monitor vehicle performance at temperature greater than 1000 C, as well as for use in the thermomechanical characterization of high temperature materials (e.g. ceramic matrix composites). While SiC alone can withstand these temperatures, a major challenge is to develop reliable electrical contacts to the device itself in order to facilitate signal extraction

Operation of a New COTS Crystal Oscillator - CXOMHT over a Wide Temperature Range

NASA Technical Reports Server (NTRS)

Patterson, Richard; Hammoud, Ahmad

2011-01-01

Crystal oscillators are extensively used in electronic circuits to provide timing or clocking signals in data acquisition, communications links, and control systems, to name a few. They are affordable, small in size, and reliable. Because of the inherent characteristics of the crystal, the oscillator usually exhibits extreme accuracy in its output frequency within the intrinsic crystal stability. Stability of the frequency could be affected under varying load levels or other operational conditions. Temperature is one of those important factors that influence the frequency stability of an oscillator; as it does to the functionality of other electronic components. Electronics designed for use in NASA deep space and planetary exploration missions are expected to be exposed to extreme temperatures and thermal cycling over a wide range. Thus, it is important to design and develop circuits that are able to operate efficiently and reliably under in these harsh temperature environments. Most of the commercial-off-the-shelf (COTS) devices are very limited in terms of their specified operational temperature while very few custom-made commercial and military-grade parts have the ability to operate in a slightly wider range of temperature than those of the COTS parts. These parts are usually designed for operation under one temperature extreme, i.e. hot or cold, and do not address the wide swing in the operational temperature, which is typical of the space environment. For safe and successful space missions, electronic systems must therefore be designed not only to withstand the extreme temperature exposure but also to operate efficiently and reliably. This report presents the results obtained on the evaluation of a new COTS crystal oscillator under extreme temperatures.

Advanced Liquid-Free, Piezoresistive, SOI-Based Pressure Sensors for Measurements in Harsh Environments.

PubMed

Ngo, Ha-Duong; Mukhopadhyay, Biswaijit; Ehrmann, Oswin; Lang, Klaus-Dieter

2015-08-18

In this paper we present and discuss two innovative liquid-free SOI sensors for pressure measurements in harsh environments. The sensors are capable of measuring pressures at high temperatures. In both concepts media separation is realized using a steel membrane. The two concepts represent two different strategies for packaging of devices for use in harsh environments and at high temperatures. The first one is a "one-sensor-one-packaging_technology" concept. The second one uses a standard flip-chip bonding technique. The first sensor is a "floating-concept", capable of measuring pressures at temperatures up to 400 °C (constant load) with an accuracy of 0.25% Full Scale Output (FSO). A push rod (mounted onto the steel membrane) transfers the applied pressure directly to the center-boss membrane of the SOI-chip, which is placed on a ceramic carrier. The chip membrane is realized by Deep Reactive Ion Etching (DRIE or Bosch Process). A novel propertied chip housing employing a sliding sensor chip that is fixed during packaging by mechanical preloading via the push rod is used, thereby avoiding chip movement, and ensuring optimal push rod load transmission. The second sensor can be used up to 350 °C. The SOI chips consists of a beam with an integrated centre-boss with was realized using KOH structuring and DRIE. The SOI chip is not "floating" but bonded by using flip-chip technology. The fabricated SOI sensor chip has a bridge resistance of 3250 Ω. The realized sensor chip has a sensitivity of 18 mV/µm measured using a bridge current of 1 mA.

The performance and capabilities of terrestrial organisms in extreme and unusual gaseous and liquid environments. Performance of fungi in exotic and harsh environments

NASA Technical Reports Server (NTRS)

Siegel, S. M.

1975-01-01

The growth of Penicillium in saline and low temperature conditions during a 15 month incubation period was studied. Data are also given on the potential 1f fungu for modification of the surface geochemistry of the earth and the capacity of these fungi to solubilize and concentrate metals.

Improving Tribological Properties of Multialkylated Cyclopentanes under Simulated Space Environment: Two Feasible Approaches.

PubMed

Fan, Xiaoqiang; Wang, Liping; Li, Wen; Wan, Shanhong

2015-07-08

Space mechanisms require multialkylated cyclopentanes (MACs) more lubricious, more reliable, more durable, and better adaptive to harsh space environments. In this study, two kinds of additives were added into MACs for improving the tribological properties under simulated space environments: (a) solid nanoparticles (tungsten disulfide (WS2), tungsten trioxide (WO3), lanthanum oxide (La2O3), and lanthanum trifluoride (LaF3)) for steel/steel contacts; (b) liquid additives like zinc dialkyldithiophosphate (ZDDP) and molybdenum dialkyldithiocarbamate (MoDTC) for steel/steel and steel/diamond-like carbon (DLC) contacts. The results show that, under harsh simulated space environments, addition of the solid nanoparticles into MACs allows the wear to be reduced by up to one order magnitude, while liquid additives simultaneously reduce friction and wear by 80% and 93%, respectively. Friction mechanisms were proposed according to surface/interface analysis techniques, such as X-ray photoelectron spectroscopy (XPS) and time-of-flight secondary ion mass spectroscopy (TOF-SIMS). The role of solid nanoparticles in reducing friction and wear mainly depends on their surface enhancement effect, and the liquid additives are attributed to the formation of tribochemical reaction film derived from ZDDP and MoDTC on the sliding surfaces.

Design of affordable and ruggedized biomedical devices using virtual instrumentation.

PubMed

Mathern, Ryan Michael; Schopman, Sarah; Kalchthaler, Kyle; Mehta, Khanjan; Butler, Peter

2013-05-01

Abstract This paper presents the designs of four low-cost and ruggedized biomedical devices, including a blood pressure monitor, thermometer, weighing scale and spirometer, designed for the East African context. The design constraints included a mass-production price point of $10, accuracy and precision comparable to commercial devices and ruggedness to function effectively in the harsh environment of East Africa. The blood pressure device, thermometer and weighing scale were field-tested in Kenya and each recorded data within 6% error of the measurements from commercial devices and withstood the adverse climate and rough handling. The spirometer functioned according to specifications, but a re-design is needed to improve operability and usability by patients. This article demonstrates the feasibility of designing and commercializing virtual instrumentation-based biomedical devices in resource-constrained environments through context-driven design. The next steps for the devices include designing them such that they can be more easily manufactured, use standardized materials, are easily calibrated in the field and have more user-friendly software programs that can be updated remotely.

Ceramic MEMS Designed for Wireless Pressure Monitoring in the Industrial Environment

PubMed Central

Pavlin, Marko; Belavic, Darko; Novak, Franc

2012-01-01

This paper presents the design of a wireless pressure-monitoring system for harsh-environment applications. Two types of ceramic pressure sensors made with a low-temperature cofired ceramic (LTCC) were considered. The first type is a piezoresistive strain gauge pressure sensor. The second type is a capacitive pressure sensor, which is based on changes of the capacitance values between two electrodes: one electrode is fixed and the other is movable under an applied pressure. The design was primarily focused on low power consumption. Reliable operation in the presence of disturbances, like electromagnetic interference, parasitic capacitances, etc., proved to be contradictory constraints. A piezoresistive ceramic pressure sensor with a high bridge impedance was chosen for use in a wireless pressure-monitoring system and an acceptable solution using energy-harvesting techniques has been achieved. The described solution allows for the integration of a sensor element with an energy harvester that has a printed thick-film battery and complete electronics in a single substrate packaged inside a compact housing. PMID:22368471

Thermal and Environmental Barrier Coatings for Advanced Propulsion Engine Systems

NASA Technical Reports Server (NTRS)

Zhu, Dong-Ming; Miller, Robert A.

2004-01-01

Ceramic thermal and environmental barrier coatings (TEBCs) are used in gas turbine engines to protect engine hot-section components in the harsh combustion environments, and extend component lifetimes. For future high performance engines, the development of advanced ceramic barrier coating systems will allow these coatings to be used to simultaneously increase engine operating temperature and reduce cooling requirements, thereby leading to significant improvements in engine power density and efficiency. In order to meet future engine performance and reliability requirements, the coating systems must be designed with increased high temperature stability, lower thermal conductivity, and improved thermal stress and erosion resistance. In this paper, ceramic coating design and testing considerations will be described for high temperature and high-heat-flux engine applications in hot corrosion and oxidation, erosion, and combustion water vapor environments. Further coating performance and life improvements will be expected by utilizing advanced coating architecture design, composition optimization, and improved processing techniques, in conjunction with modeling and design tools.

High fidelity, radiation tolerant analog-to-digital converters

NASA Technical Reports Server (NTRS)

Wang, Charles Chang-I (Inventor); Linscott, Ivan Richard (Inventor); Inan, Umran S. (Inventor)

2012-01-01

Techniques for an analog-to-digital converter (ADC) using pipeline architecture includes a linearization technique for a spurious-free dynamic range (SFDR) over 80 deciBels. In some embodiments, sampling rates exceed a megahertz. According to a second approach, a switched-capacitor circuit is configured for correct operation in a high radiation environment. In one embodiment, the combination yields high fidelity ADC (>88 deciBel SFDR) while sampling at 5 megahertz sampling rates and consuming <60 milliWatts. Furthermore, even though it is manufactured in a commercial 0.25-.mu.m CMOS technology (1 .mu.m=12.sup.-6 meters), it maintains this performance in harsh radiation environments. Specifically, the stated performance is sustained through a highest tested 2 megarad(Si) total dose, and the ADC displays no latchup up to a highest tested linear energy transfer of 63 million electron Volts square centimeters per milligram at elevated temperature (131 degrees C.) and supply (2.7 Volts, versus 2.5 Volts nominal).

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

DOEpatents

Blackburn, Bryan M; Wachsman, Eric D

2015-05-12

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

Assessment of Durable SiC JFET Technology for +600 C to -125 C Integrated Circuit Operation

NASA Technical Reports Server (NTRS)

Neudeck, P. G.; Krasowski, M. J.; Prokop, N. F.

2011-01-01

Electrical characteristics and circuit design considerations for prototype 6H-SiC JFET integrated circuits (ICs) operating over the broad temperature range of -125 C to +600 C are described. Strategic implementation of circuits with transistors and resistors in the same 6H-SiC n-channel layer enabled ICs with nearly temperature-independent functionality to be achieved. The frequency performance of the circuits declined at temperatures increasingly below or above room temperature, roughly corresponding to the change in 6H-SiC n-channel resistance arising from incomplete carrier ionization at low temperature and decreased electron mobility at high temperature. In addition to very broad temperature functionality, these simple digital and analog demonstration integrated circuits successfully operated with little change in functional characteristics over the course of thousands of hours at 500 C before experiencing interconnect-related failures. With appropriate further development, these initial results establish a new technology foundation for realizing durable 500 C ICs for combustion engine sensing and control, deep-well drilling, and other harsh-environment applications.

High-temperature long-lasting stability assessment of a single-crystal diamond detector under high-flux neutron irradiation

NASA Astrophysics Data System (ADS)

Pilotti, R.; Angelone, M.; Marinelli, M.; Milani, E.; Verona-Rinati, G.; Verona, C.; Prestopino, G.; Montereali, R. M.; Vincenti, M. A.; Schooneveld, E. M.; Scherillo, A.; Pietropaolo, A.

2016-11-01

An innovative diamond detector layout is presented that is designed to operate at high temperature under intense neutron and gamma fluxes. It is made of a 500 μm “electronic grade” diamond film with 100 nm thick Ag metal contacts deposited onto each surface of the film by means of thermal evaporation. A 2 μ \\text{m} thick layer of 6LiF has been deposited on top of one of the two Ag contacts to make the detector sensitive to thermal neutrons. The device was tested at the ISIS spallation neutron source (Rutherford Appleton Laboratory, UK) using the INES beam line. The detector was continuously irradiated for 100 hours in vacuum (p = 10-5 \\text{mbar}) , exposed to a neutron flux of about 106 n cm-2 s-1 at a temperature T =150 ^\\circ \\text{C} . The aim of this experiment was to study the time dependence of the diamond detector performance while operating at high temperature under irradiation, providing a first experimental proof of reliable continuous operation for 100 hours at high temperature in a harsh environment.

Virtual Teaching on the Tundra.

ERIC Educational Resources Information Center

McAuley, Alexander

1998-01-01

Describes how a teacher and a distance-learning consultant collaborate in using the Internet and Computer Supported Intentional Learning Environment (CISILE) to connect multicultural students on the harsh Baffin Island (Canada). Discusses the creation of the class's database and future implications. (AEF)

Advanced Materials and Coatings for Aerospace Applications

NASA Technical Reports Server (NTRS)

Miyoshi, Kazuhisa

2004-01-01

In the application area of aerospace tribology, researchers and developers must guarantee the highest degree of reliability for materials, components, and systems. Even a small tribological failure can lead to catastrophic results. The absence of the required knowledge of tribology, as Professor H.P. Jost has said, can act as a severe brake in aerospace vehicle systems-and indeed has already done so. Materials and coatings must be able to withstand the aerospace environments that they encounter, such as vacuum terrestrial, ascent, and descent environments; be resistant to the degrading effects of air, water vapor, sand, foreign substances, and radiation during a lengthy service; be able to withstand the loads, stresses, and temperatures encountered form acceleration and vibration during operation; and be able to support reliable tribological operations in harsh environments throughout the mission of the vehicle. This presentation id divided into two sections: surface properties and technology practice related to aerospace tribology. The first section is concerned with the fundamental properties of the surfaces of solid-film lubricants and related materials and coatings, including carbon nanotubes. The second is devoted to applications. Case studies are used to review some aspects of real problems related to aerospace systems to help engineers and scientists to understand the tribological issues and failures. The nature of each problem is analyzed, and the tribological properties are examined. All the fundamental studies and case studies were conducted at the NASA Glenn Research Center.

TBM/MTM for HTS-FNSF: An innovative testing strategy to qualify/validate fusion technologies for U.S. DEMO

DOE PAGES

El-Guebaly, Laila; Rowcliffe, Arthur; Menard, Jonathan; ...

2016-08-11

The qualification and validation of nuclear technologies are daunting tasks for fusion demonstration (DEMO) and power plants. This is particularly true for advanced designs that involve harsh radiation environment with 14 MeV neutrons and high-temperature operating regimes. This paper outlines the unique qualification and validation processes developed in the U.S., offering the only access to the complete fusion environment, focusing on the most prominent U.S. blanket concept (the dual cooled PbLi (DCLL)) along with testing new generations of structural and functional materials in dedicated test modules. The venue for such activities is the proposed Fusion Nuclear Science Facility (FNSF), whichmore » is viewed as an essential element of the U.S. fusion roadmap. A staged blanket testing strategy has been developed to test and enhance the DCLL blanket performance during each phase of FNSF D-T operation. A materials testing module (MTM) is critically important to include in the FNSF as well to test a broad range of specimens of future, more advanced generations of materials in a relevant fusion environment. Here, the most important attributes for MTM are the relevant He/dpa ratio (10–15) and the much larger specimen volumes compared to the 10–500 mL range available in the International Fusion Materials Irradiation Facility (IFMIF) and European DEMO-Oriented Neutron Source (DONES).« less

High temperature, harsh environment sensors for advanced power generation systems

NASA Astrophysics Data System (ADS)

Ohodnicki, P. R.; Credle, S.; Buric, M.; Lewis, R.; Seachman, S.

2015-05-01

One mission of the Crosscutting Technology Research program at the National Energy Technology Laboratory is to develop a suite of sensors and controls technologies that will ultimately increase efficiencies of existing fossil-fuel fired power plants and enable a new generation of more efficient and lower emission power generation technologies. The program seeks to accomplish this mission through soliciting, managing, and monitoring a broad range of projects both internal and external to the laboratory which span sensor material and device development, energy harvesting and wireless telemetry methodologies, and advanced controls algorithms and approaches. A particular emphasis is placed upon harsh environment sensing for compatibility with high temperature, erosive, corrosive, and highly reducing or oxidizing environments associated with large-scale centralized power generation. An overview of the full sensors and controls portfolio is presented and a selected set of current and recent research successes and on-going projects are highlighted. A more detailed emphasis will be placed on an overview of the current research thrusts and successes of the in-house sensor material and device research efforts that have been established to support the program.

Visual analysis of trash bin processing on garbage trucks in low resolution video

NASA Astrophysics Data System (ADS)

Sidla, Oliver; Loibner, Gernot

2015-03-01

We present a system for trash can detection and counting from a camera which is mounted on a garbage collection truck. A working prototype has been successfully implemented and tested with several hours of real-world video. The detection pipeline consists of HOG detectors for two trash can sizes, and meanshift tracking and low level image processing for the analysis of the garbage disposal process. Considering the harsh environment and unfavorable imaging conditions, the process works already good enough so that very useful measurements from video data can be extracted. The false positive/false negative rate of the full processing pipeline is about 5-6% at fully automatic operation. Video data of a full day (about 8 hrs) can be processed in about 30 minutes on a standard PC.

Gaseous electron multiplier-based soft x-ray plasma diagnostics development: Preliminary tests at ASDEX Upgrade.

PubMed

Chernyshova, M; Malinowski, K; Czarski, T; Wojeński, A; Vezinet, D; Poźniak, K T; Kasprowicz, G; Mazon, D; Jardin, A; Herrmann, A; Kowalska-Strzęciwilk, E; Krawczyk, R; Kolasiński, P; Zabołotny, W; Zienkiewicz, P

2016-11-01

A Gaseous Electron Multiplier (GEM)-based detector is being developed for soft X-ray diagnostics on tokamaks. Its main goal is to facilitate transport studies of impurities like tungsten. Such studies are very relevant to ITER, where the excessive accumulation of impurities in the plasma core should be avoided. This contribution provides details of the preliminary tests at ASDEX Upgrade (AUG) with a focus on the most important aspects for detector operation in harsh radiation environment. It was shown that both spatially and spectrally resolved data could be collected, in a reasonable agreement with other AUG diagnostics. Contributions to the GEM signal include also hard X-rays, gammas, and neutrons. First simulations of the effect of high-energy photons have helped understanding these contributions.

Gaseous electron multiplier-based soft x-ray plasma diagnostics development: Preliminary tests at ASDEX Upgrade

NASA Astrophysics Data System (ADS)

Chernyshova, M.; Malinowski, K.; Czarski, T.; Wojeński, A.; Vezinet, D.; Poźniak, K. T.; Kasprowicz, G.; Mazon, D.; Jardin, A.; Herrmann, A.; Kowalska-Strzeciwilk, E.; Krawczyk, R.; Kolasiński, P.; Zabołotny, W.; Zienkiewicz, P.

2016-11-01

A Gaseous Electron Multiplier (GEM)-based detector is being developed for soft X-ray diagnostics on tokamaks. Its main goal is to facilitate transport studies of impurities like tungsten. Such studies are very relevant to ITER, where the excessive accumulation of impurities in the plasma core should be avoided. This contribution provides details of the preliminary tests at ASDEX Upgrade (AUG) with a focus on the most important aspects for detector operation in harsh radiation environment. It was shown that both spatially and spectrally resolved data could be collected, in a reasonable agreement with other AUG diagnostics. Contributions to the GEM signal include also hard X-rays, gammas, and neutrons. First simulations of the effect of high-energy photons have helped understanding these contributions.

Evaluation of 1.5-T Cell Flash Memory Total Ionizing Dose Response

NASA Astrophysics Data System (ADS)

Clark, Lawrence T.; Holbert, Keith E.; Adams, James W.; Navale, Harshad; Anderson, Blake C.

2015-12-01

Flash memory is an essential part of systems used in harsh environments, experienced by both terrestrial and aerospace TID applications. This paper presents studies of COTS flash memory TID hardness. While there is substantial literature on flash memory TID response, this work focuses for the first time on 1.5 transistor per cell flash memory. The experimental results show hardness varying from about 100 krad(Si) to over 250 krad(Si) depending on the usage model. We explore the circuit and device aspects of the results, based on the extensive reliability literature for this flash memory type. Failure modes indicate both device damage and circuit marginalities. Sector erase failure limits, but read only operation allows TID exceeding 200 krad(Si). The failures are analyzed by type.

Development of Simulated Disturbing Source for Isolation Switch

NASA Astrophysics Data System (ADS)

Cheng, Lin; Liu, Xiang; Deng, Xiaoping; Pan, Zhezhe; Zhou, Hang; Zhu, Yong

2018-01-01

In order to simulate the substation in the actual scene of the harsh electromagnetic environment, and then research on electromagnetic compatibility testing of electronic instrument transformer, On the basis of the original isolation switch as a harassment source of the electronic instrument transformer electromagnetic compatibility test system, an isolated switch simulation source system was developed, to promote the standardization of the original test. In this paper, the circuit breaker is used to control the opening and closing of the gap arc to simulate the operating of isolating switch, and the isolation switch simulation harassment source system is designed accordingly. Comparison with the actual test results of the isolating switch, it is proved that the system can meet the test requirements, and the simulation harassment source system has good stability and high reliability.

An automated calibration laboratory for flight research instrumentation: Requirements and a proposed design approach

NASA Technical Reports Server (NTRS)

Oneill-Rood, Nora; Glover, Richard D.

1990-01-01

NASA's Dryden Flight Research Facility (Ames-Dryden), operates a diverse fleet of research aircraft which are heavily instrumented to provide both real time data for in-flight monitoring and recorded data for postflight analysis. Ames-Dryden's existing automated calibration (AUTOCAL) laboratory is a computerized facility which tests aircraft sensors to certify accuracy for anticipated harsh flight environments. Recently, a major AUTOCAL lab upgrade was initiated; the goal of this modernization is to enhance productivity and improve configuration management for both software and test data. The new system will have multiple testing stations employing distributed processing linked by a local area network to a centralized database. The baseline requirements for the new AUTOCAL lab and the design approach being taken for its mechanization are described.

Operation of a New Half-Bridge Gate Driver for Enhancement - Mode GaN FETs, Type LM5113, Over a Wide Temperature Range

NASA Technical Reports Server (NTRS)

Patterson, Richard; Hammoud, Ahmad

2011-01-01

A new commercial-off-the-shelf (COTS) gate driver designed to drive both the high-side and the low-side enhancement-mode GaN FETs, National Semiconductor's type LM5113, was evaluated for operation at temperatures beyond its recommended specified limits of -40 C to +125 C. The effects of limited thermal cycling under the extended test temperature, which ranged from -194 C to +150 C, on the operation of this chip as well as restart capability at the extreme cryogenic and hot temperatures were also investigated. The driver circuit was able to maintain good operation throughout the entire test regime between -194 C and +150 C without undergoing any major changes in its outputs signals and characteristics. The limited thermal cycling performed on the device also had no effect on its performance, and the driver chip was able to successfully restart at each of the extreme temperatures of -194 C and +150 C. The plastic packaging of this device was also not affected by either the short extreme temperature exposure or the limited thermal cycling. These preliminary results indicate that this new commercial-off-the-shelf (COTS) halfbridge eGaN FET driver integrated circuit has the potential for use in space exploration missions under extreme temperature environments. Further testing is planned under long-term cycling to assess the reliability of these parts and to determine their suitability for extended use in the harsh environments of space.

Sensor Based Engine Life Calculation: A Probabilistic Perspective

NASA Technical Reports Server (NTRS)

Guo, Ten-Huei; Chen, Philip

2003-01-01

It is generally known that an engine component will accumulate damage (life usage) during its lifetime of use in a harsh operating environment. The commonly used cycle count for engine component usage monitoring has an inherent range of uncertainty which can be overly costly or potentially less safe from an operational standpoint. With the advance of computer technology, engine operation modeling, and the understanding of damage accumulation physics, it is possible (and desirable) to use the available sensor information to make a more accurate assessment of engine component usage. This paper describes a probabilistic approach to quantify the effects of engine operating parameter uncertainties on the thermomechanical fatigue (TMF) life of a selected engine part. A closed-loop engine simulation with a TMF life model is used to calculate the life consumption of different mission cycles. A Monte Carlo simulation approach is used to generate the statistical life usage profile for different operating assumptions. The probabilities of failure of different operating conditions are compared to illustrate the importance of the engine component life calculation using sensor information. The results of this study clearly show that a sensor-based life cycle calculation can greatly reduce the risk of component failure as well as extend on-wing component life by avoiding unnecessary maintenance actions.

High performing solution-coated electrolyte-gated organic field-effect transistors for aqueous media operation.

PubMed

Zhang, Qiaoming; Leonardi, Francesca; Casalini, Stefano; Temiño, Inés; Mas-Torrent, Marta

2016-12-22

Since the first demonstration, the electrolyte-gated organic field-effect transistors (EGOFETs) have immediately gained much attention for the development of cutting-edge technology and they are expected to have a strong impact in the field of (bio-)sensors. However EGOFETs directly expose their active material towards the aqueous media, hence a limited library of organic semiconductors is actually suitable. By using two mostly unexplored strategies in EGOFETs such as blended materials together with a printing technique, we have successfully widened this library. Our benchmarks were 6,13-bis(triisopropylsilylethynyl)pentacene and 2,8-difluoro-5,11-bis(triethylsilylethynyl)anthradithiophene (diF-TES-ADT), which have been firstly blended with polystyrene and secondly deposited by means of the bar-assisted meniscus shearing (BAMS) technique. Our approach yielded thin films (i.e. no thicker than 30 nm) suitable for organic electronics and stable in liquid environment. Up to date, these EGOFETs show unprecedented performances. Furthermore, an extremely harsh environment, like NaCl 1M, has been used in order to test the limit of operability of these electronic devices. Albeit an electrical worsening is observed, our devices can operate under different electrical stresses within the time frame of hours up to a week. In conclusion, our approach turns out to be a powerful tool for the EGOFET manufacturing.

High performing solution-coated electrolyte-gated organic field-effect transistors for aqueous media operation

NASA Astrophysics Data System (ADS)

Zhang, Qiaoming; Leonardi, Francesca; Casalini, Stefano; Temiño, Inés; Mas-Torrent, Marta

2016-12-01

Since the first demonstration, the electrolyte-gated organic field-effect transistors (EGOFETs) have immediately gained much attention for the development of cutting-edge technology and they are expected to have a strong impact in the field of (bio-)sensors. However EGOFETs directly expose their active material towards the aqueous media, hence a limited library of organic semiconductors is actually suitable. By using two mostly unexplored strategies in EGOFETs such as blended materials together with a printing technique, we have successfully widened this library. Our benchmarks were 6,13-bis(triisopropylsilylethynyl)pentacene and 2,8-difluoro-5,11-bis(triethylsilylethynyl)anthradithiophene (diF-TES-ADT), which have been firstly blended with polystyrene and secondly deposited by means of the bar-assisted meniscus shearing (BAMS) technique. Our approach yielded thin films (i.e. no thicker than 30 nm) suitable for organic electronics and stable in liquid environment. Up to date, these EGOFETs show unprecedented performances. Furthermore, an extremely harsh environment, like NaCl 1M, has been used in order to test the limit of operability of these electronic devices. Albeit an electrical worsening is observed, our devices can operate under different electrical stresses within the time frame of hours up to a week. In conclusion, our approach turns out to be a powerful tool for the EGOFET manufacturing.

High performing solution-coated electrolyte-gated organic field-effect transistors for aqueous media operation

PubMed Central

Zhang, Qiaoming; Leonardi, Francesca; Casalini, Stefano; Temiño, Inés; Mas-Torrent, Marta

2016-01-01

Since the first demonstration, the electrolyte-gated organic field-effect transistors (EGOFETs) have immediately gained much attention for the development of cutting-edge technology and they are expected to have a strong impact in the field of (bio-)sensors. However EGOFETs directly expose their active material towards the aqueous media, hence a limited library of organic semiconductors is actually suitable. By using two mostly unexplored strategies in EGOFETs such as blended materials together with a printing technique, we have successfully widened this library. Our benchmarks were 6,13-bis(triisopropylsilylethynyl)pentacene and 2,8-difluoro-5,11-bis(triethylsilylethynyl)anthradithiophene (diF-TES-ADT), which have been firstly blended with polystyrene and secondly deposited by means of the bar-assisted meniscus shearing (BAMS) technique. Our approach yielded thin films (i.e. no thicker than 30 nm) suitable for organic electronics and stable in liquid environment. Up to date, these EGOFETs show unprecedented performances. Furthermore, an extremely harsh environment, like NaCl 1M, has been used in order to test the limit of operability of these electronic devices. Albeit an electrical worsening is observed, our devices can operate under different electrical stresses within the time frame of hours up to a week. In conclusion, our approach turns out to be a powerful tool for the EGOFET manufacturing. PMID:28004824

Comprehensive Numerical Modeling of the Blast Furnace Ironmaking Process

NASA Astrophysics Data System (ADS)

Zhou, Chenn; Tang, Guangwu; Wang, Jichao; Fu, Dong; Okosun, Tyamo; Silaen, Armin; Wu, Bin

2016-05-01

Blast furnaces are counter-current chemical reactors, widely utilized in the ironmaking industry. Hot reduction gases injected from lower regions of the furnace ascend, reacting with the descending burden. Through this reaction process, iron ore is reduced into liquid iron that is tapped from the furnace hearth. Due to the extremely harsh environment inside the blast furnace, it is difficult to measure or observe internal phenomena during operation. Through the collaboration between steel companies and the Center for Innovation through Visualization and Simulation, multiple computational fluid dynamics (CFD) models have been developed to simulate the complex multiphase reacting flow in the three regions of the furnace, the shaft, the raceway, and the hearth. The models have been used effectively to troubleshoot and optimize blast furnace operations. In addition, the CFD models have been integrated with virtual reality. An interactive virtual blast furnace has been developed for training purpose. This paper summarizes the developments and applications of blast furnace CFD models and the virtual blast furnace.

Investigating Degradation Mechanisms in 130 nm and 90 nm Commercial CMOS Technologies Under Extreme Radiation Conditions

NASA Astrophysics Data System (ADS)

Ratti, Lodovico; Gaioni, Luigi; Manghisoni, Massimo; Traversi, Gianluca; Pantano, Devis

2008-08-01

The purpose of this paper is to study the mechanisms underlying performance degradation in 130 nm and 90 nm commercial CMOS technologies exposed to high doses of ionizing radiation. The investigation has been mainly focused on their noise properties in view of applications to the design of low-noise, low-power analog circuits to be operated in harsh environment. Experimental data support the hypothesis that charge trapping in shallow trench isolation (STI), besides degrading the static characteristics of interdigitated NMOS transistors, also affects their noise performances in a substantial fashion. The model discussed in this paper, presented in a previous work focused on CMOS devices irradiated with a 10 Mrad(SiO2) gamma -ray dose, has been applied here also to transistors exposed to much higher (up to 100 Mrad(SiO2 )) doses of X-rays. Such a model is able to account for the extent of the observed noise degradation as a function of the device polarity, dimensions and operating point.

Measurement of Turbulent Pressure and Temperature Fluctuations in a Gas Turbine Combustor

NASA Technical Reports Server (NTRS)

Passaro, Andrea; LaGraff, John E.; Oldfield, Martin L. G.; Biagioni, Leonardo; Moss, Roger W.; Battelle, Ryan T.; Povinelli, Louis A. (Technical Monitor)

2003-01-01

The present research concerns the development of high-frequency pressure and temperature probes and related instrumentation capable of performing spectral characterization of unsteady pressure and temperature fluctuations over the 0.05 20 kHz range, at the exit of a gas turbine combustor operating at conditions close to nominal ones for large power generation turbomachinery. The probes used a transient technique pioneered at Oxford University; in order to withstand exposure to the harsh environment the probes were fitted on a rapid injection and cooling system jointly developed by Centrospazio CPR and Syracuse University. The experimental runs were performed on a large industrial test rig being operated by ENEL Produzione. The achieved results clearly show the satisfactory performance provided by this diagnostic tool, even though the poor location of the injection port prevented the tests from yielding more insight of the core flow turbulence characteristics. The pressure and temperature probes survived several dozen injections in the combustor hot jet, while consistently providing the intended high frequency performance. The apparatus was kept connected to the combustor during long duration firings, operating as an unobtrusive, self contained, piggy-back experiment: high frequency flow samplings were remotely recorded at selected moments corresponding to different combustor operating conditions.

A Brief Review of the Need for Robust Smart Wireless Sensor Systems for Future Propulsion Systems, Distributed Engine Controls, and Propulsion Health Management

NASA Technical Reports Server (NTRS)

Hunter, Gary W.; Behbahani, Alireza

2012-01-01

Smart Sensor Systems with wireless capability operational in high temperature, harsh environments are a significant component in enabling future propulsion systems to meet a range of increasingly demanding requirements. These propulsion systems must incorporate technology that will monitor engine component conditions, analyze the incoming data, and modify operating parameters to optimize propulsion system operations. This paper discusses the motivation towards the development of high temperature, smart wireless sensor systems that include sensors, electronics, wireless communication, and power. The challenges associated with the use of traditional wired sensor systems will be reviewed and potential advantages of Smart Sensor Systems will be discussed. A brief review of potential applications for wireless smart sensor networks and their potential impact on propulsion system operation, with emphasis on Distributed Engine Control and Propulsion Health Management, will be given. A specific example related to the development of high temperature Smart Sensor Systems based on silicon carbide electronics will be discussed. It is concluded that the development of a range of robust smart wireless sensor systems are a foundation for future development of intelligent propulsion systems with enhanced capabilities.

Progress and prospect of true steady state operation with RF

NASA Astrophysics Data System (ADS)

Jacquinot, Jean

2017-10-01

Operation of fusion confinement experiments in full steady state is a major challenge for the development towards fusion energy. Critical to achieving this goal is the availability of actively cooled plasma facing components and auxiliary systems withstanding the very harsh plasma environment. Equally challenging are physics issues related to achieving plasma conditions and current drive efficiency required by reactor plasmas. RF heating and current drive systems have been key instruments for obtaining the progress made until today towards steady state. They hold all the records of long pulse plasma operation both in tokamaks and in stellarators. Nevertheless much progress remains to be made in particular for integrating all the requirements necessary for maintaining in steady state the density and plasma pressure conditions of a reactor. This is an important stated aim of ITER and of devices equipped with superconducting magnets. After considering the present state of the art, this review will address the key issues which remain to be solved both in physics and technology for reaching this goal. They constitute very active subjects of research which will require much dedicated experimentation in the new generation of superconducting devices which are now in operation or becoming close to it.

Bioadhesive Polymersome for Localized and Sustained Drug Delivery at Pathological Sites with Harsh Enzymatic and Fluidic Environment via Supramolecular Host-Guest Complexation.

PubMed

Zhu, Meiling; Wei, Kongchang; Lin, Sien; Chen, Xiaoyu; Wu, Chia-Ching; Li, Gang; Bian, Liming

2018-02-01

Targeted and sustained delivery of drugs to diseased tissues/organs, where body fluid exchange and catabolic activity are substantial, is challenging due to the fast cleansing and degradation of the drugs by these harsh environmental factors. Herein, a multifunctional and bioadhesive polycaprolactone-β-cyclodextrin (PCL-CD) polymersome is developed for localized and sustained co-delivery of hydrophilic and hydrophobic drug molecules. This PCL-CD polymersome affords multivalent crosslinking action via surface CD-mediated host-guest interactions to generate a supramolecular hydrogel that exhibits evident shear thinning and efficient self-healing behavior. The co-delivery of small molecule and proteinaceous agents by the encapsulated PCL-CD polymersomes enhances the differentiation of stem cells seeded in the hydrogel. Furthermore, the PCL-CD polymersomes are capable of in situ grafting to biological tissues via host-guest complexation between surface CD and native guest groups in the tissue matrix both in vitro and in vivo, thereby effectively extending the retention of loaded cargo in the grafted tissue. It is further demonstrated that the co-delivery of small molecule and proteinaceous drugs via PCL-CD polymersomes averts cartilage degeneration in animal osteoarthritic (OA) knee joints, which are known for their biochemically harsh and fluidically dynamic environment. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Durability of carbon fiber reinforced shape memory polymer composites in space

NASA Astrophysics Data System (ADS)

Jang, Joon Hyeok; Hong, Seok Bin; Ahn, Yong San; Kim, Jin-Gyun; Nam, Yong-Youn; Lee, Geun Ho; Yu, Woong-Ryeol

2016-04-01

Shape memory polymer (SMP) is one of smart polymers which exhibit shape memory effect upon external stimuli. Recently, shape memory polymer composites (SMPCs) have been considered for space structure instead of shape memory alloys due to their deformability, lightweight and large recovery ratio, requiring characterization of their mechanical properties against harsh space environment and further prediction of the durability of SMPCs in space. As such, the durability of carbon fiber reinforced shape memory polymer composites (CF-SMPCs) was investigated using accelerated testing method based on short-term testing of CF-SMPCs in harsh condition. CF-SMPCs were prepared using woven carbon fabrics and a thermoset SMP via vacuum assisted resin transfer molding process. Bending tests with constant strain rate of CF-SMPCs were conducted using universal tensile machine (UTM) and Storage modulus test were conducted using dynamic mechanical thermal analysis (DMTA). Using the results, a master curve based on time-temperature superposition principle was then constructed, through which the mechanical properties of CF-SMPCs at harsh temperature were predicted. CF-SMPCs would be exposed to simulated space environments under ultra-violet radiations at various temperatures. The mechanical properties including flexural and tensile strength and shape memory properties of SMPCs would be measured using UTM before and after such exposures for comparison. Finally, the durability of SMPCs in space would be assessed by developing a degradation model of SMPC.

Fiber-coupled 2.7 µm laser absorption sensor for CO2 in harsh combustion environments

NASA Astrophysics Data System (ADS)

Spearrin, R. M.; Goldenstein, C. S.; Jeffries, J. B.; Hanson, R. K.

2013-05-01

A tunable diode laser absorption sensor near 2.7 µm, based on 1f-normalized wavelength-modulation spectroscopy with second-harmonic detection (WMS-2f), was developed to measure CO2 concentration in harsh combustion flows. Wavelength selection at 3733.48 cm-1 exploited the overlap of two CO2 transitions in the ν1 + ν3 vibrational band at 3733.468 cm-1 and 3733.498 cm-1. Primary factors influencing wavelength selection were isolation and strength of the CO2 absorption lines relative to infrared water absorption at elevated pressures and temperatures. The HITEMP 2010 database was used to model the combined CO2 and H2O absorption spectra, and key line-strength and line-broadening spectroscopic parameters were verified by high-temperature static cell measurements. To validate the accuracy and precision of the WMS-based sensor, measurements of CO2 concentration were carried out in non-reactive shock-tube experiments (P ˜ 3-12 atm, T ˜ 1000-2600 K). The laser was then free-space fiber-coupled with a zirconium fluoride single-mode fiber for remote light delivery to harsh combustion environments, and demonstrated on an ethylene/air pulse detonation combustor at pressures up to 10 atm and temperatures up to 2500 K. To our knowledge, this work represents the first time-resolved in-stream measurements of CO2 concentration in a detonation-based engine.

Xilinx Virtex-5QV (V5QV) Independent SEU Data

NASA Technical Reports Server (NTRS)

Berg, Melanie D.; LaBel, Kenneth A.; Pellish, Jonathan

2014-01-01

This is an independent study to determine the single event destructive and transient susceptibility of the Xilinx Virtex-5QV (SIRF) device. A framework for evaluating complex digital systems targeted for harsh radiation environments such as space is presented.

Autonomous low-power magnetic data collection platform to enable remote high latitude array deployment.

PubMed

Musko, Stephen B; Clauer, C Robert; Ridley, Aaron J; Arnett, Kennneth L

2009-04-01

A major driver in the advancement of geophysical sciences is improvement in the quality and resolution of data for use in scientific analysis, discovery, and for assimilation into or validation of empirical and physical models. The need for more and better measurements together with improvements in technical capabilities is driving the ambition to deploy arrays of autonomous geophysical instrument platforms in remote regions. This is particularly true in the southern polar regions where measurements are presently sparse due to the remoteness, lack of infrastructure, and harshness of the environment. The need for the acquisition of continuous long-term data from remote polar locations exists across geophysical disciplines and is a generic infrastructure problem. The infrastructure, however, to support autonomous instrument platforms in polar environments is still in the early stages of development. We report here the development of an autonomous low-power magnetic variation data collection system. Following 2 years of field testing at the south pole station, the system is being reproduced to establish a dense chain of stations on the Antarctic plateau along the 40 degrees magnetic meridian. The system is designed to operate for at least 5 years unattended and to provide data access via satellite communication. The system will store 1 s measurements of the magnetic field variation (<0.2 nT resolution) in three vector components plus a variety of engineering status and environment parameters. We believe that the data collection platform can be utilized by a variety of low-power instruments designed for low-temperature operation. The design, technical characteristics, and operation results are presented here.

Systems and methods for wave energy conversion

DOEpatents

MacDonald, Daniel G.; Cantara, Justin; Nathan, Craig; Lopes, Amy M.; Green, Brandon E.

2017-02-28

Systems for wave energy conversion that have components that can survive the harsh marine environment and that can be attached to fixed structures, such as a pier, and having the ability to naturally adjust for tidal height and methods for their use are presented.

Corrosion evaluation of novel coatings for steel components of highway bridges : [summary].

DOT National Transportation Integrated Search

2015-04-01

Steel components make up all or part of Florida bridges. Many are subject to harsh marine : environments, but all are exposed to Floridas high humidity and rainfall, which can lead to : corrosion. Durable protective coatings are needed to protect ...

Silicon Carbide Nanotube Synthesized

NASA Technical Reports Server (NTRS)

Lienhard, Michael A.; Larkin, David J.

2003-01-01

Carbon nanotubes (CNTs) have generated a great deal of scientific and commercial interest because of the countless envisioned applications that stem from their extraordinary materials properties. Included among these properties are high mechanical strength (tensile and modulus), high thermal conductivity, and electrical properties that make different forms of single-walled CNTs either conducting or semiconducting, and therefore, suitable for making ultraminiature, high-performance CNT-based electronics, sensors, and actuators. Among the limitations for CNTs is their inability to survive in high-temperature, harsh-environment applications. Silicon carbon nanotubes (SiCNTs) are being developed for their superior material properties under such conditions. For example, SiC is stable in regards to oxidation in air to temperatures exceeding 1000 C, whereas carbon-based materials are limited to 600 C. The high-temperature stability of SiCNTs is envisioned to enable high-temperature, harsh-environment nanofiber- and nanotube-reinforced ceramics. In addition, single-crystal SiC-based semiconductors are being developed for hightemperature, high-power electronics, and by analogy to CNTs with silicon semiconductors, SiCNTs with single-crystal SiC-based semiconductors may allow high-temperature harsh-environment nanoelectronics, nanosensors, and nanoactuators to be realized. Another challenge in CNT development is the difficulty of chemically modifying the tube walls, which are composed of chemically stable graphene sheets. The chemical substitution of the CNTs walls will be necessary for nanotube self-assembly and biological- and chemical-sensing applications. SiCNTs are expected to have a different multiple-bilayer wall structure, allowing the surface Si atoms to be functionalized readily with molecules that will allow SiCNTs to undergo self-assembly and be compatible with a variety of materials (for biotechnology applications and high-performance fiber-reinforced ceramics).

Advanced Liquid-Free, Piezoresistive, SOI-Based Pressure Sensors for Measurements in Harsh Environments

PubMed Central

Ngo, Ha-Duong; Mukhopadhyay, Biswaijit; Ehrmann, Oswin; Lang, Klaus-Dieter

2015-01-01

In this paper we present and discuss two innovative liquid-free SOI sensors for pressure measurements in harsh environments. The sensors are capable of measuring pressures at high temperatures. In both concepts media separation is realized using a steel membrane. The two concepts represent two different strategies for packaging of devices for use in harsh environments and at high temperatures. The first one is a “one-sensor-one-packaging_technology” concept. The second one uses a standard flip-chip bonding technique. The first sensor is a “floating-concept”, capable of measuring pressures at temperatures up to 400 °C (constant load) with an accuracy of 0.25% Full Scale Output (FSO). A push rod (mounted onto the steel membrane) transfers the applied pressure directly to the center-boss membrane of the SOI-chip, which is placed on a ceramic carrier. The chip membrane is realized by Deep Reactive Ion Etching (DRIE or Bosch Process). A novel propertied chip housing employing a sliding sensor chip that is fixed during packaging by mechanical preloading via the push rod is used, thereby avoiding chip movement, and ensuring optimal push rod load transmission. The second sensor can be used up to 350 °C. The SOI chips consists of a beam with an integrated centre-boss with was realized using KOH structuring and DRIE. The SOI chip is not “floating” but bonded by using flip-chip technology. The fabricated SOI sensor chip has a bridge resistance of 3250 Ω. The realized sensor chip has a sensitivity of 18 mV/µm measured using a bridge current of 1 mA. PMID:26295235

Electronics for Low Temperature Space Exploration Missions

NASA Technical Reports Server (NTRS)

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

2007-01-01

Exploration missions to outer planets and deep space require spacecraft, probes, and on-board data and communication systems to operate reliably and efficiently under severe harsh conditions. On-board electronics, in particular those in direct exposures to the space environment without any shielding or protection, will encounter extreme low temperature and thermal cycling in their service cycle in most of NASA s upcoming exploration missions. For example, Venus atmosphere, Jupiter atmosphere, Moon surface, Pluto orbiter, Mars, comets, Titan, Europa, and James Webb Space Telescope all involve low-temperature surroundings. Therefore, electronics for space exploration missions need to be designed for operation under such environmental conditions. There are ongoing efforts at the NASA Glenn Research Center (GRC) to establish a database on the operation and reliability of electronic devices and circuits under extreme temperature operation for space applications. This work is being performed under the Extreme Temperature Electronics Program with collaboration and support of the NASA Electronic Parts and Packaging (NEPP) Program. The results of these investigations will be used to establish safe operating areas and to identify degradation and failure modes, and the information will be disseminated to mission planners and system designers for use as tools for proper part selection and in risk mitigation. An overview of this program along with experimental data will be presented.

Electrochemical investigation of stainless steel corrosion in a proton exchange membrane electrolyzer cell

DOE PAGES

Mo, Jingke; Steen, Stuart M.; Zhang, Feng-Yuan; ...

2015-08-05

The lack of a fundamental understanding of the corrosion mechanisms in the electrochemical environments of proton exchange membrane (PEM) electrolyzer and/or fuel cells (ECs/FCs) has seriously hindered the improvement of performance and efficiency of PEM ECs/FCs. In this study, a stainless steel mesh was purposely used as an anode gas diffusion layer that was intentionally operated with high positive potentials under harsh oxidative environments in a PEMEC to study the corrosion mechanism of metal migration. A significant amount of iron and nickel cations were determined to transport through the anode catalyst layer, the PEM and the cathode catalyst layer duringmore » the PEMEC operation. The formation/deposition of iron oxide and nickel oxide on the carbon paper gas diffusion layer at the cathode side is first revealed by both scanning electron microscope and X-ray diffraction. The results indicate the corrosion elements of iron and nickel are transported from anode to cathode through the catalyst-coated membrane, and deposited on carbon fibers as oxides. This phenomenon could also open a new corrosion-based processing approach to potentially fabricate multifunctional oxide structures on carbon fiber devices. This study has demonstrated a new accelerated test method for investigating the corrosion and durability of metallic materials as well.« less

Electrochemical investigation of stainless steel corrosion in a proton exchange membrane electrolyzer cell

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

Mo, Jingke; Steen, Stuart M.; Zhang, Feng-Yuan

The lack of a fundamental understanding of the corrosion mechanisms in the electrochemical environments of proton exchange membrane (PEM) electrolyzer and/or fuel cells (ECs/FCs) has seriously hindered the improvement of performance and efficiency of PEM ECs/FCs. In this study, a stainless steel mesh was purposely used as an anode gas diffusion layer that was intentionally operated with high positive potentials under harsh oxidative environments in a PEMEC to study the corrosion mechanism of metal migration. A significant amount of iron and nickel cations were determined to transport through the anode catalyst layer, the PEM and the cathode catalyst layer duringmore » the PEMEC operation. The formation/deposition of iron oxide and nickel oxide on the carbon paper gas diffusion layer at the cathode side is first revealed by both scanning electron microscope and X-ray diffraction. The results indicate the corrosion elements of iron and nickel are transported from anode to cathode through the catalyst-coated membrane, and deposited on carbon fibers as oxides. This phenomenon could also open a new corrosion-based processing approach to potentially fabricate multifunctional oxide structures on carbon fiber devices. This study has demonstrated a new accelerated test method for investigating the corrosion and durability of metallic materials as well.« less

A hazard control system for robot manipulators

NASA Technical Reports Server (NTRS)

Carter, Ruth Chiang; Rad, Adrian

1991-01-01

A robot for space applications will be required to complete a variety of tasks in an uncertain, harsh environment. This fact presents unusual and highly difficult challenges to ensuring the safety of astronauts and keeping the equipment they depend on from becoming damaged. The systematic approach being taken to control hazards that could result from introducing robotics technology in the space environment is described. First, system safety management and engineering principles, techniques, and requirements are discussed as they relate to Shuttle payload design and operation in general. The concepts of hazard, hazard category, and hazard control, as defined by the Shuttle payload safety requirements, is explained. Next, it is shown how these general safety management and engineering principles are being implemented on an actual project. An example is presented of a hazard control system for controlling one of the hazards identified for the Development Test Flight (DTF-1) of NASA's Flight Telerobotic Servicer, a teleoperated space robot. How these schemes can be applied to terrestrial robots is discussed as well. The same software monitoring and control approach will insure the safe operation of a slave manipulator under teleoperated or autonomous control in undersea, nuclear, or manufacturing applications where the manipulator is working in the vicinity of humans or critical hardware.

Electrical Characterization of Irradiated Semiconducting Amorphous Hydrogenated Boron Carbide

NASA Astrophysics Data System (ADS)

Peterson, George Glenn

Semiconducting amorphous partially dehydrogenated boron carbide has been explored as a neutron voltaic for operation in radiation harsh environments, such as on deep space satellites/probes. A neutron voltaic device could also be used as a solid state neutron radiation detector to provide immediate alerts for radiation workers/students, as opposed to the passive dosimetry badges utilized today. Understanding how the irradiation environment effects the electrical properties of semiconducting amorphous partially dehydrogenated boron carbide is important to predicting the stability of these devices in operation. p-n heterojunction diodes were formed from the synthesis of semiconducting amorphous partially dehydrogenated boron carbide on silicon substrates through the use of plasma enhanced chemical vapor deposition (PECVD). Many forms of structural and electrical measurements and analysis have been performed on the p-n heterojunction devices as a function of both He+ ion and neutron irradiation including: transmission electron microscopy (TEM), selected area electron diffraction (SAED), current versus voltage I(V), capacitance versus voltage C(V), conductance versus frequency G(f), and charge carrier lifetime (tau). In stark contrast to nearly all other electronic devices, the electrical performance of these p-n heterojunction diodes improved with irradiation. This is most likely the result of bond defect passivation and resolution of degraded icosahedral based carborane structures (icosahedral molecules missing a B, C, or H atom(s)).

Logic integration of mRNA signals by an RNAi-based molecular computer.

PubMed

Xie, Zhen; Liu, Siyuan John; Bleris, Leonidas; Benenson, Yaakov

2010-05-01

Synthetic in vivo molecular 'computers' could rewire biological processes by establishing programmable, non-native pathways between molecular signals and biological responses. Multiple molecular computer prototypes have been shown to work in simple buffered solutions. Many of those prototypes were made of DNA strands and performed computations using cycles of annealing-digestion or strand displacement. We have previously introduced RNA interference (RNAi)-based computing as a way of implementing complex molecular logic in vivo. Because it also relies on nucleic acids for its operation, RNAi computing could benefit from the tools developed for DNA systems. However, these tools must be harnessed to produce bioactive components and be adapted for harsh operating environments that reflect in vivo conditions. In a step toward this goal, we report the construction and implementation of biosensors that 'transduce' mRNA levels into bioactive, small interfering RNA molecules via RNA strand exchange in a cell-free Drosophila embryo lysate, a step beyond simple buffered environments. We further integrate the sensors with our RNAi 'computational' module to evaluate two-input logic functions on mRNA concentrations. Our results show how RNA strand exchange can expand the utility of RNAi computing and point toward the possibility of using strand exchange in a native biological setting.

Logic integration of mRNA signals by an RNAi-based molecular computer

PubMed Central

Xie, Zhen; Liu, Siyuan John; Bleris, Leonidas; Benenson, Yaakov

2010-01-01

Synthetic in vivo molecular ‘computers’ could rewire biological processes by establishing programmable, non-native pathways between molecular signals and biological responses. Multiple molecular computer prototypes have been shown to work in simple buffered solutions. Many of those prototypes were made of DNA strands and performed computations using cycles of annealing-digestion or strand displacement. We have previously introduced RNA interference (RNAi)-based computing as a way of implementing complex molecular logic in vivo. Because it also relies on nucleic acids for its operation, RNAi computing could benefit from the tools developed for DNA systems. However, these tools must be harnessed to produce bioactive components and be adapted for harsh operating environments that reflect in vivo conditions. In a step toward this goal, we report the construction and implementation of biosensors that ‘transduce’ mRNA levels into bioactive, small interfering RNA molecules via RNA strand exchange in a cell-free Drosophila embryo lysate, a step beyond simple buffered environments. We further integrate the sensors with our RNAi ‘computational’ module to evaluate two-input logic functions on mRNA concentrations. Our results show how RNA strand exchange can expand the utility of RNAi computing and point toward the possibility of using strand exchange in a native biological setting. PMID:20194121

Reliability improvement methods for sapphire fiber temperature sensors

NASA Astrophysics Data System (ADS)

Schietinger, C.; Adams, B.

1991-08-01

Mechanical, optical, electrical, and software design improvements can be brought to bear in the enhancement of fiber-optic sapphire-fiber temperature measurement tool reliability in harsh environments. The optical fiber thermometry (OFT) equipment discussed is used in numerous process industries and generally involves a sapphire sensor, an optical transmission cable, and a microprocessor-based signal analyzer. OFT technology incorporating sensors for corrosive environments, hybrid sensors, and two-wavelength measurements, are discussed.

Compact Full-Field Ion Detector System for SmallSats Beyond LEO

NASA Technical Reports Server (NTRS)

Wrbanek, John D.; Wrbanek, Susan Y.; Fralick, Gustave C.; Clark, Pamela E.; McNeil, Roger R.

2014-01-01

NASA Glenn Research Center (GRC) is applying its expertise and facilities in harsh environment instrumentation to develop a Compact Full-Field Ion Detector System (CFIDS). The CFIDS is designed to be an extremely compact, low cost instrument, capable of being flown on a wide variety of deep space platforms, to provide multi-directional, comprehensive (composition, velocity, and direction) in-situ measurements of heavy ions in space plasma environments.

Post-tensioned carbon fiber composite cable (CFCC), Little Pond Bridge, Route 302, Fryeburg, Maine.

DOT National Transportation Integrated Search

2013-02-01

Corrosion of reinforcing steel in concrete has been a constant and expensive maintenance problem which : is exacerbated by Maines coastal environment, harsh winters, and the use of chlorides on the roads and : bridges. Carbon fiber products are in...

Wearable Oximetry for Harsh Environments

DTIC Science & Technology

characterize the types and significance of motion artifacts that will need to be mitigated. The forehead was confirmed to be an excellent site with...respect to signal quality, but signal corruption from changes in contact pressure will need to be mitigated. The sternal locations are initially assessed

A laboratory and field study of composite piles for bridge substructures

DOT National Transportation Integrated Search

2006-03-01

The most commonly used pile materials are steel, concrete, and wood. These materials can degrade, and the degradation rate can be relatively rapid in harsh marine environments. It has been estimated that the U.S. spends over $1 billion annually for r...

OIL SPILL RESPONSE SCENARIOS FOR REMOTE ARCTIC ENVIRONMENTS

EPA Science Inventory

Special problems occur during oil spill cleanup in remote inland areas in cold climates. In Alaska these problems result from the harsh climate, the unusual terrain features, and the special problems of spills along swift rivers. The analysis begins with a description of the envi...

A Cortically Implantable Multielectrode Array for Investigating the Mammalian Visual System.

DTIC Science & Technology

1981-12-01

AFIT Multielectrode Array from the harsh cerebro - spinal environment encountered inside the cranium. Secondary emphasis is placed on analyzing the...experience before a primate implant). This is a particularly exciting period for neurocortical research because we are at the brink of significant

Thin and Flexible Fe-Si-B/Ni-Cu-P Metallic Glass Multilayer Composites for Efficient Electromagnetic Interference Shielding.

PubMed

Zhang, Jijun; Li, Jiawei; Tan, Guoguo; Hu, Renchao; Wang, Junqiang; Chang, Chuntao; Wang, Xinmin

2017-12-06

Thin and flexible materials that can provide efficient electromagnetic interference (EMI) shielding are urgently needed, especially if they can be easily processed and withstand harsh environments. Herein, layer-structured Fe-Si-B/Ni-Cu-P metallic glass composites have been developed by simple electroless plating Ni-Cu-P coating on commercial Fe-Si-B metallic glasses. The 0.1 mm-thick composite shows EMI shielding effectiveness of 40 dB over the X-band frequency range, which is higher than those of traditional metals, metal oxides, and their polymer composites of larger thickness. Most of the applied electromagnetic waves are proved to be absorbed rather than bounced back. This performance originates from the combination of a superior soft magnetic property, excellent electrical conductivity, and multiple internal reflections from multilayer composites. In addition, the flexible composites also exhibit good corrosion resistance, high thermal stability, and excellent tensile strength, making them suitable for EMI shielding in harsh chemical or thermal environments.

Radio-frequency plasma transducer for use in harsh environments.

PubMed

May, Andrew; Andarawis, Emad

2007-10-01

We describe a compact transducer used to generate and modulate low-intensity radio-frequency atmospheric pressure plasma (RF-APP) for high temperature gap measurement and generation of air-coupled ultrasound. The new transducer consists of a quarter-wave transmission line where the ground return path is a coaxial solenoid winding. The RF-APP is initiated at the open end of the transmission line and stabilized by passive negative feedback between the electrical impedance of the plasma and the energy stored in the solenoid. The electrical impedance of the plasma was measured at the lower-voltage source end of the transducer, eliminating the need to measure kilovolt-level voltages near the discharge. We describe the use of a 7 MHz RF-APP prototype as a harsh-environment clearance sensor to demonstrate the suitability of plasma discharges for a common nondestructive inspection application. Clearance measurements of 0-5 mm were performed on a rotating calibration target with a measurement precision of 0.1 mm and a 20 kHz sampling rate.

Femtosecond laser ablated durable superhydrophobic PTFE films with micro-through-holes for oil/water separation: Separating oil from water and corrosive solutions

NASA Astrophysics Data System (ADS)

Yong, Jiale; Fang, Yao; Chen, Feng; Huo, Jinglan; Yang, Qing; Bian, Hao; Du, Guangqing; Hou, Xun

2016-12-01

Separating the mixture of water and oil by the superhydrophobic porous materials has attracted increasing research interests; however, the surface microstructures and chemical composition of those materials are easily destroyed in a harsh environment, resulting in materials losing the superhydrophobicity as well as the oil/water separation function. In this paper, a kind of rough microstructures was formed on polytetrafluoroethylene (PTFE) sheet by femtosecond laser treatment. The rough surfaces showed durable superhydrophobicity and ultralow water adhesion even after storing in various harsh environment for a long time, including strong acid, strong alkali, and high temperature. A micro-through-holes array was further generated on the rough superhydrophobic PTFE film by a subsequent mechanical drilling process. The resultant sample was successfully applied in the field of oil/water separation due to the inverse superhydrophobicity and superoleophilicity. The designed separation system is also very efficient to separate the mixtures of oil and corrosive acid/alkali solutions, exhibiting the strong potential for practical application.

Switching kinetics of SiC resistive memory for harsh environments

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

Morgan, K. A., E-mail: kam2g11@soton.ac.uk; Huang, R.; Groot, C. H. de

2015-07-15

Cu/a-SiC/Au resistive memory cells are measured using voltage pulses and exhibit the highest R{sub OFF}/R{sub ON} ratio recorded for any resistive memory. The switching kinetics are investigated and fitted to a numerical model, using thermal conductivity and resistivity properties of the dielectric. The SET mechanism of the Cu/a-SiC/Au memory cells is found to be due to ionic motion without joule heating contributions, whereas the RESET mechanism is found to be due to thermally assisted ionic motion. The conductive filament diameter is extracted to be around 4nm. The high thermal conductivity and resistivity for the Cu/a-SiC/Au memory cells result in slowmore » switching but with high thermal reliability and stability, showing potential for use in harsh environments. Radiation properties of SiC memory cells are investigated. No change was seen in DC sweep or pulsed switching nor in conductive mechanisms, up to 2Mrad(Si) using {sup 60}Co gamma irradiation.« less

A library of protein cage architectures as nanomaterials.

PubMed

Flenniken, M L; Uchida, M; Liepold, L O; Kang, S; Young, M J; Douglas, T

2009-01-01

Virus capsids and other structurally related cage-like proteins such as ferritins, dps, and heat shock proteins have three distinct surfaces (inside, outside, interface) that can be exploited to generate nanomaterials with multiple functionality by design. Protein cages are biological in origin and each cage exhibits extremely homogeneous size distribution. This homogeneity can be used to attain a high degree of homogeneity of the templated material and its associated property. A series of protein cages exhibiting diversity in size, functionality, and chemical and thermal stabilities can be utilized for materials synthesis under a variety of conditions. Since synthetic approaches to materials science often use harsh temperature and pH, it is an advantage to utilize protein cages from extreme environments. In this chapter, we review recent studies on discovering novel protein cages from harsh natural environments such as the acidic thermal hot springs at Yellowstone National Park (YNP) and on utilizing protein cages as nano-scale platforms for developing nanomaterials with wide range of applications from electronics to biomedicine.

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.

Detection of Artificially Generated Seismic Signals Using Balloon-Borne Infrasound Sensors

NASA Astrophysics Data System (ADS)

Krishnamoorthy, Siddharth; Komjathy, Attila; Pauken, Michael T.; Cutts, James A.; Garcia, Raphael F.; Mimoun, David; Cadu, Alexandre; Sournac, Anthony; Jackson, Jennifer M.; Lai, Voon Hui; Bowman, Daniel C.

2018-04-01

We conducted an experiment in Pahrump, Nevada, in June 2017, where artificial seismic signals were created using a seismic hammer, and the possibility of detecting them from their acoustic signature was examined. In this work, we analyze the pressure signals recorded by highly sensitive barometers deployed on the ground and on tethers suspended from balloons. Our signal processing results show that wind noise experienced by a barometer on a free-flying balloon is lower compared to one on a moored balloon. This has never been experimentally demonstrated in the lower troposphere. While seismoacoustic signals were not recorded on the hot air balloon platform owing to operational challenges, we demonstrate the detection of seismoacoustic signals on our moored balloon platform. Our results have important implications for performing seismology in harsh surface environments such as Venus through atmospheric remote sensing.

Calcium-magnesium Aluminosilicate (CMAS) Interactions with Advanced Environmental Barrier Coating Material

NASA Technical Reports Server (NTRS)

Wiesner, Valerie L.; Bansal, Narottam P.

2015-01-01

Particulates, like sand and volcanic ash, threaten the development of robust environmental barrier coatings (EBCs) that protect next-generation silicon-based ceramic matrix composite (CMC) turbine engine components from harsh combustion environments during service. The siliceous particulates transform into molten glassy deposits of calcium-magnesium aluminosilicate (CMAS) when ingested by an aircraft engine operating at temperatures above 1200C. In this study, a sample of desert sand was melted into CMAS glass to evaluate high-temperature interactions between the sand glass and an advanced EBC material. Desert sand glass was added to the surface of hot-pressed EBC substrates, which were then heated in air at temperatures ranging from 1200C to 1500C. Scanning electron microscopy and X-ray energy-dispersive spectroscopy were used to evaluate microstructure and phase compositions of specimens and the CMASEBC interface after heat treatments.

Process-Hardened, Multi-Analyte Sensor for Characterizing Rocket Plume Constituents

NASA Technical Reports Server (NTRS)

Goswami, Kisholoy

2011-01-01

A multi-analyte sensor was developed that enables simultaneous detection of rocket engine combustion-product molecules in a launch-vehicle ground test stand. The sensor was developed using a pin-printing method by incorporating multiple sensor elements on a single chip. It demonstrated accurate and sensitive detection of analytes such as carbon dioxide, carbon monoxide, kerosene, isopropanol, and ethylene from a single measurement. The use of pin-printing technology enables high-volume fabrication of the sensor chip, which will ultimately eliminate the need for individual sensor calibration since many identical sensors are made in one batch. Tests were performed using a single-sensor chip attached to a fiber-optic bundle. The use of a fiber bundle allows placement of the opto-electronic readout device at a place remote from the test stand. The sensors are rugged for operation in harsh environments.

Analytical method for establishing indentation rolling resistance

NASA Astrophysics Data System (ADS)

Gładysiewicz, Lech; Konieczna, Martyna

2018-01-01

Belt conveyors are highly reliable machines able to work in special operating conditions. Harsh environment, long distance of transporting and great mass of transported martials are cause of high energy usage. That is why research in the field of belt conveyor transportation nowadays focuses on reducing the power consumption without lowering their efficiency. In this paper, previous methods for testing rolling resistance are described, and new method designed by authors was presented. New method of testing rolling resistance is quite simple and inexpensive. Moreover it allows to conduct the experimental tests of the impact of different parameters on the value of indentation rolling resistance such as core design, cover thickness, ambient temperature, idler travel frequency, or load value as well. Finally results of tests of relationship between rolling resistance and idler travel frequency and between rolling resistance and idler travel speed was presented.

Multi-spectral temperature measurement method for gas turbine blade

NASA Astrophysics Data System (ADS)

Gao, Shan; Feng, Chi; Wang, Lixin; Li, Dong

2016-02-01

One of the basic methods to improve both the thermal efficiency and power output of a gas turbine is to increase the firing temperature. However, gas turbine blades are easily damaged in harsh high-temperature and high-pressure environments. Therefore, ensuring that the blade temperature remains within the design limits is very important. There are unsolved problems in blade temperature measurement, relating to the emissivity of the blade surface, influences of the combustion gases, and reflections of radiant energy from the surroundings. In this study, the emissivity of blade surfaces has been measured, with errors reduced by a fitting method, influences of the combustion gases have been calculated for different operational conditions, and a reflection model has been built. An iterative computing method is proposed for calculating blade temperatures, and the experimental results show that this method has high precision.

Gaseous electron multiplier-based soft x-ray plasma diagnostics development: Preliminary tests at ASDEX Upgrade

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

Chernyshova, M., E-mail: maryna.chernyshova@ipplm.pl; Malinowski, K.; Czarski, T.

2016-11-15

A Gaseous Electron Multiplier (GEM)-based detector is being developed for soft X-ray diagnostics on tokamaks. Its main goal is to facilitate transport studies of impurities like tungsten. Such studies are very relevant to ITER, where the excessive accumulation of impurities in the plasma core should be avoided. This contribution provides details of the preliminary tests at ASDEX Upgrade (AUG) with a focus on the most important aspects for detector operation in harsh radiation environment. It was shown that both spatially and spectrally resolved data could be collected, in a reasonable agreement with other AUG diagnostics. Contributions to the GEM signalmore » include also hard X-rays, gammas, and neutrons. First simulations of the effect of high-energy photons have helped understanding these contributions.« less

Wireless Monitoring of the Height of Condensed Water in Steam Pipes

NASA Technical Reports Server (NTRS)

Lee, Hyeong Jae; Bar-Cohen, Yoseph; Lih, Shyh-Shiuh; Badescu, Mircea; Dingizian, Arsham; Takano, Nobuyuki; Blosiu, Julian O.

2014-01-01

A wireless health monitoring system has been developed for determining the height of water condensation in the steam pipes and the data acquisition is done remotely using a wireless network system. The developed system is designed to operate in the harsh environment encountered at manholes and the pipe high temperature of over 200 °C. The test method is an ultrasonic pulse-echo and the hardware includes a pulser, receiver and wireless modem for communication. Data acquisition and signal processing software were developed to determine the water height using adaptive signal processing and data communication that can be controlled while the hardware is installed in a manhole. A statistical decision-making tool is being developed based on the field test data to determine the height of in the condensed water under high noise conditions and other environmental factors.

Operational Lessons Learned in the Korean War

DTIC Science & Technology

2011-12-01

per response, including the time for reviewing instructions, searching existing data sources , gathering and maintaining the data needed, and...marines and soldiers faced sub-zero temperatures and heavy snowfall that blocked mountain passes and clogged main supply routes. Fifty years later...soldiers and airmen serving in Korea experienced another such harsh winter that limited operations because of heavy snowfall and had an impact their

The Leadership Imperative

ERIC Educational Resources Information Center

Baliles, Gerald L.

2006-01-01

The expanding pressures on the modern academic president today range from the ever-present demands for fund-raising, to calls for greater accountability and productivity, to proliferating special-interest groups, to steadily harsh criticism from inside and outside the academy. In this pressure-cooker environment, it takes a special kind of…

The Effect of pH on Stability and Sorption of Cryptosporidium parvum Oocysts by Nanoparticles

EPA Science Inventory

Cryptosporidium parvum (C. parvum) are waterborne pathogens, which are released into the environment through infected human or animal feces. Their ability to survive outside their host organisms in harsh environmental conditions presents one of the most challenging tasks in resea...

Issues with the Application of Thermographic Phosphors to Measure High Temperatures in a Gas Turbine Engines

NASA Astrophysics Data System (ADS)

Khalid, A. H.; Kontis, K.

2009-01-01

The demand for more efficient engines is increasing as concerns over greenhouse gases continue to grow. Performance can be increased if higher turbine inlet temperatures are achieved. However, this increases the chance of material failure. Therefore, the optimum temperature is prescribed by the balance between the benefits of thermal efficiency and material life. To ensure safety and reliability, uncertainty in temperature measurement forces the engine to be operated below its thermal design limit. Accurate surface measurement offers the potential to increase engine performance by allowing them to operate closer to this limit. It can allow designers to better understand flow physics, and greatly facilitate the testing and development of newer thermal protection systems and concepts. The aim of this paper is to highlight the motivations of using phosphor thermometry in gas turbine environments as an alternative to current measurement methods such as discrete thermocouple measurements and pyrometry. Phosphor thermometry offers many advantages over conventional techniques. However, the harsh, high temperature and fast rotating environment presents some unique challenges and the paper further aims to discuss the issues that would arise in such environments. There will be increasing blackbody radiation, restrictions to optical access and time available to collect emissions. There will be imposed upper and lower temperature limits and other restrictions that will greatly influence the design of the measurement system, including the choice of phosphor, bonding technique, excitation and detection methodologies. A system would have to be bespoke to suit the end measurement goal.

Inflight proton activation and damage on a CdTe detection plane

NASA Astrophysics Data System (ADS)

Simões, N.; Maia, J. M.; Curado da Silva, R. M.; Ghithan, S.; Crespo, P.; do Carmo, S. J. C.; Alves, Francisco; Moita, M.; Auricchio, N.; Caroli, E.

2018-01-01

Future high-energy space telescope missions require further analysis of orbital environment induced activation and radiation damage on main instruments. A scientific satellite is exposed to the charged particles harsh environment, mainly geomagnetically trapped protons (up to ∼300 MeV) that interact with the payload materials, generating nuclear activation background noise within instruments' operational energy range and causing radiation damage in detector material. As a consequence, instruments' performances deteriorate during the mission time-frame. In order to optimize inflight operational performances of future CdTe high-energy telescope detection planes under orbital radiation environment, we measured and analyzed the effects generated by protons on CdTe ACRORAD detectors with 2.56 cm2 sensitive area and 2 mm thickness. To carry-out this study, several sets of measurements were performed under a ∼14 MeV cyclotron proton beam. Nuclear activation radionuclides' identification was performed. Estimation of activation background generated by short-lived radioisotopes during one day was less than ∼1.3 ×10-5 counts cm-2 s-1 keV-1 up to 800 keV. A noticeable gamma-rays energy resolution degradation was registered (∼60% @ 122 keV, ∼14% @ 511 and ∼2.2% @ 1275 keV) after an accumulated proton fluence of 4.5 ×1010 protons cm-2, equivalent to ∼22 years in-orbit fluence. One year later, the energy resolution of the irradiated prototype showed a good level of performancerecovery.

Analyzing System on A Chip Single Event Upset Responses using Single Event Upset Data, Classical Reliability Models, and Space Environment Data

NASA Technical Reports Server (NTRS)

Berg, Melanie; LaBel, Kenneth; Campola, Michael; Xapsos, Michael

2017-01-01

We are investigating the application of classical reliability performance metrics combined with standard single event upset (SEU) analysis data. We expect to relate SEU behavior to system performance requirements. Our proposed methodology will provide better prediction of SEU responses in harsh radiation environments with confidence metrics. single event upset (SEU), single event effect (SEE), field programmable gate array devises (FPGAs)

Techniques utilized in the simulated altitude testing of a 2D-CD vectoring and reversing nozzle

NASA Technical Reports Server (NTRS)

Block, H. Bruce; Bryant, Lively; Dicus, John H.; Moore, Allan S.; Burns, Maureen E.; Solomon, Robert F.; Sheer, Irving

1988-01-01

Simulated altitude testing of a two-dimensional, convergent-divergent, thrust vectoring and reversing exhaust nozzle was accomplished. An important objective of this test was to develop test hardware and techniques to properly operate a vectoring and reversing nozzle within the confines of an altitude test facility. This report presents detailed information on the major test support systems utilized, the operational performance of the systems and the problems encountered, and test equipment improvements recommended for future tests. The most challenging support systems included the multi-axis thrust measurement system, vectored and reverse exhaust gas collection systems, and infrared temperature measurement systems used to evaluate and monitor the nozzle. The feasibility of testing a vectoring and reversing nozzle of this type in an altitude chamber was successfully demonstrated. Supporting systems performed as required. During reverser operation, engine exhaust gases were successfully captured and turned downstream. However, a small amount of exhaust gas spilled out the collector ducts' inlet openings when the reverser was opened more than 60 percent. The spillage did not affect engine or nozzle performance. The three infrared systems which viewed the nozzle through the exhaust collection system worked remarkably well considering the harsh environment.

What is Good University Financial Management?

ERIC Educational Resources Information Center

Taylor, Mark P.

2013-01-01

In the current and foreseeable harsh UK higher education environment, aspiring to best-practice financial management will be key to ensuring the prosperity--and indeed the survival--of any university. In this article I argue that good university financial management should provide stability to the institution, allow for investment as well as…

CMOS Ultra Low Power Radiation Tolerant (CULPRiT) Microelectronics

NASA Technical Reports Server (NTRS)

Yeh, Penshu; Maki, Gary

2007-01-01

Space Electronics needs Radiation Tolerance or hardness to withstand the harsh space environment: high-energy particles can change the state of the electronics or puncture transistors making them disfunctional. This viewgraph document reviews the use of CMOS Ultra Low Power Radiation Tolerant circuits for NASA's electronic requirements.

Maternal Distress Explains the Relationship of Young African American Mothers' Violence Exposure with Their Preschoolers' Behavior

ERIC Educational Resources Information Center

Mitchell, Stephanie J.; Lewin, Amy; Rasmussen, Andrew; Horn, Ivor B.; Joseph, Jill G.

2011-01-01

Adolescent mothers and their children are particularly susceptible to witnessing or directly experiencing violence. Such violence exposure predicts maternal distress, parenting, and child behavior problems. The current study examined how mothers' depressive symptoms, aggression, harsh disciplinary practices, and home environment independently…

The DREAMS experiment flown on the ExoMars 2016 mission for the study of Martian environment during the dust storm season

NASA Astrophysics Data System (ADS)

Bettanini, C.; Esposito, R.; Debei, S.; Molfese, C.; Colombatti, G.; Aboudan, A.; Brucato, J. R.; Cortecchia, F.; Di Achille, G.; Guizzo, G. P.; Friso, E.; Ferri, F.; Marty, L.; Mennella, V.; Molinaro, R.; Schipani, P.; Silvestro, S.; Mugnuolo, R.; Pirrotta, S.; Marchetti, E.; Harri, A.-M.; Montmessin, F.; Wilson, C.; Arruego Rodriguez, I.; Abbaki, S.; Apestigue, V.; Bellucci, G.; Berthelier, J. J.; Calcutt, S. B.; Forget, F.; Genzer, M.; Gilbert, P.; Haukka, H.; Jimenez, J. J.; Jimenez, S.; Josset, J. L.; Karatekin, O.; Landis, G.; Lorenz, R.; Martinez, J.; Möhlmann, D.; Moirin, D.; Palomba, E.; Pateli, M.; Pommereau, J.-P.; Popa, C. I.; Rafkin, S.; Rannou, P.; Renno, N. O.; Schmidt, W.; Simoes, F.; Spiga, A.; Valero, F.; Vazquez, L.; Vivat, F.; Witasse, O.

2017-08-01

The DREAMS (Dust characterization, Risk assessment and Environment Analyser on the Martian Surface) experiment on Schiaparelli lander of ExoMars 2016 mission was an autonomous meteorological station designed to completely characterize the Martian atmosphere on surface, acquiring data not only on temperature, pressure, humidity, wind speed and direction, but also on solar irradiance, dust opacity and atmospheric electrification, to measure for the first time key parameters linked to hazard conditions for future manned explorations. Although with very limited mass and energy resources, DREAMS would be able to operate autonomously for at least two Martian days (sols) after landing in a very harsh environment as it was supposed to land on Mars during the dust storm season (October 2016 in Meridiani Planum) relying on its own power supply. ExoMars mission was successfully launched on 14th March 2016 and Schiaparelli entered the Mars atmosphere on October 20th beginning its 'six minutes of terror' journey to the surface. Unfortunately, some unexpected behavior during the parachuted descent caused an unrecoverable critical condition in navigation system of the lander driving to a destructive crash on the surface. The adverse sequence of events at 4 km altitude triggered the transition of the lander in surface operative mode, commanding switch on the DREAMS instrument, which was therefore able to correctly power on and send back housekeeping data. This proved the nominal performance of all DREAMS hardware before touchdown demonstrating the highest TRL of the unit for future missions. This paper describes this experiment in terms of scientific goals, design, performances, testing and operational capabilities with an overview of in flight performances and available mission data.

Performance enhanced piezoelectric-based crack detection system for high temperature I-beam SHM

NASA Astrophysics Data System (ADS)

Zhang, Chen; Zhang, Haifeng

2017-04-01

This paper proposes an innovative sensing system for high temperature (up to 150°C) I-beam crack detection. The proposed system is based on the piezoelectric effect and laser sensing mechanisms, which is proved to be effective at high temperature environment (up to 150°C). Different from other high temperature SHM approaches, the proposed sensing system is employing a piezoelectric disk as an actuator and a laser vibrometer as a sensor for remote detection. Lab tests are carried out and the vibrational properties are studied to characterize the relationship between crack depth and sensor responses by analyzing the RMS of sensor responses. Instead of utilizing a pair of piezoelectric actuator and sensor, using the laser vibrometer will enable 1) a more flexible detection, which will not be limited to specific area or dimension, 2) wireless sensing, which lowers the risk of operating at high temperature/harsh environment. The proposed sensing system can be applied to engineering structures such as in nuclear power plant reactor vessel and heat pipe structures/systems.

High Temperature Near-Field NanoThermoMechanical Rectification

PubMed Central

Elzouka, Mahmoud; Ndao, Sidy

2017-01-01

Limited performance and reliability of electronic devices at extreme temperatures, intensive electromagnetic fields, and radiation found in space exploration missions (i.e., Venus & Jupiter planetary exploration, and heliophysics missions) and earth-based applications requires the development of alternative computing technologies. In the pursuit of alternative technologies, research efforts have looked into developing thermal memory and logic devices that use heat instead of electricity to perform computations. However, most of the proposed technologies operate at room or cryogenic temperatures, due to their dependence on material’s temperature-dependent properties. Here in this research, we show experimentally—for the first time—the use of near-field thermal radiation (NFTR) to achieve thermal rectification at high temperatures, which can be used to build high-temperature thermal diodes for performing logic operations in harsh environments. We achieved rectification through the coupling between NFTR and the size of a micro/nano gap separating two terminals, engineered to be a function of heat flow direction. We fabricated and tested a proof-of-concept NanoThermoMechanical device that has shown a maximum rectification of 10.9% at terminals’ temperatures of 375 and 530 K. Experimentally, we operated the microdevice in temperatures as high as about 600 K, demonstrating this technology’s suitability to operate at high temperatures. PMID:28322324

Final technical report. In-situ FT-IR monitoring of a black liquor recovery boiler

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

James Markham; Joseph Cosgrove; David Marran

1999-05-31

This project developed and tested advanced Fourier transform infrared (FT-IR) instruments for process monitoring of black liquor recovery boilers. The state-of-the-art FT-IR instruments successfully operated in the harsh environment of a black liquor recovery boiler and provided a wealth of real-time process information. Concentrations of multiple gas species were simultaneously monitored in-situ across the combustion flow of the boiler and extractively at the stack. Sensitivity to changes of particulate fume and carryover levels in the process flow were also demonstrated. Boiler set-up and operation is a complex balance of conditions that influence the chemical and physical processes in the combustionmore » flow. Operating parameters include black liquor flow rate, liquor temperature, nozzle pressure, primary air, secondary air, tertiary air, boiler excess oxygen and others. The in-process information provided by the FT-IR monitors can be used as a boiler control tool since species indicative of combustion efficiency (carbon monoxide, methane) and pollutant emissions (sulfur dioxide, hydrochloric acid and fume) were monitored in real-time and observed to fluctuate as operating conditions were varied. A high priority need of the U.S. industrial boiler market is improved measurement and control technology. The sensor technology demonstrated in this project is applicable to the need of industry.« less

High Temperature Near-Field NanoThermoMechanical Rectification

NASA Astrophysics Data System (ADS)

Elzouka, Mahmoud; Ndao, Sidy

2017-03-01

Limited performance and reliability of electronic devices at extreme temperatures, intensive electromagnetic fields, and radiation found in space exploration missions (i.e., Venus & Jupiter planetary exploration, and heliophysics missions) and earth-based applications requires the development of alternative computing technologies. In the pursuit of alternative technologies, research efforts have looked into developing thermal memory and logic devices that use heat instead of electricity to perform computations. However, most of the proposed technologies operate at room or cryogenic temperatures, due to their dependence on material’s temperature-dependent properties. Here in this research, we show experimentally—for the first time—the use of near-field thermal radiation (NFTR) to achieve thermal rectification at high temperatures, which can be used to build high-temperature thermal diodes for performing logic operations in harsh environments. We achieved rectification through the coupling between NFTR and the size of a micro/nano gap separating two terminals, engineered to be a function of heat flow direction. We fabricated and tested a proof-of-concept NanoThermoMechanical device that has shown a maximum rectification of 10.9% at terminals’ temperatures of 375 and 530 K. Experimentally, we operated the microdevice in temperatures as high as about 600 K, demonstrating this technology’s suitability to operate at high temperatures.

Plastic Deformation of Micromachined Silicon Diaphragms with a Sealed Cavity at High Temperatures

PubMed Central

Ren, Juan; Ward, Michael; Kinnell, Peter; Craddock, Russell; Wei, Xueyong

2016-01-01

Single crystal silicon (SCS) diaphragms are widely used as pressure sensitive elements in micromachined pressure sensors. However, for harsh environments applications, pure silicon diaphragms are hardly used because of the deterioration of SCS in both electrical and mechanical properties. To survive at the elevated temperature, the silicon structures must work in combination with other advanced materials, such as silicon carbide (SiC) or silicon on insulator (SOI), for improved performance and reduced cost. Hence, in order to extend the operating temperatures of existing SCS microstructures, this work investigates the mechanical behavior of pressurized SCS diaphragms at high temperatures. A model was developed to predict the plastic deformation of SCS diaphragms and was verified by the experiments. The evolution of the deformation was obtained by studying the surface profiles at different anneal stages. The slow continuous deformation was considered as creep for the diaphragms with a radius of 2.5 mm at 600 °C. The occurrence of plastic deformation was successfully predicted by the model and was observed at the operating temperature of 800 °C and 900 °C, respectively. PMID:26861332

Benefits and limitations of composites in carrier-based aircraft

NASA Technical Reports Server (NTRS)

Mcerlean, Donald P.

1992-01-01

There are many unique aspects of Navy air missions that lead to the differentiation between the design and performance of ship and shore-based aircraft. The major aspects are discussed from which essentially all Navy aircraft design requirements derive. (1) Navy aircraft operate from carriers at sea imposes a broad spectrum of physical conditions, constraints, and requirements ranging from the harsh sea environment, the space limitations of a carrier, takeoff and landing requirements as well as for endurance at long distances from the carrier. (2) Because the carrier and its airwing are intended to be capable of responding to a broad range of contingencies, mission flexibility is essential (maximum weapon carriage, rapid reconfiguration, multiple mission capability). (3) The embarked aircraft provides the long range defense of the battle group against air, surface and subsurface launched antiship missiles. (4) The carrier and its aircraft must operate independently and outside of normal supply lines. Taking into account these aspects, the use of composite materials in the design and performance of naval aircraft is outlined, also listing advantages and disadvantages.

Design and simulation of a 800 Mbit/s data link for magnetic resonance imaging wearables.

PubMed

Vogt, Christian; Buthe, Lars; Petti, Luisa; Cantarella, Giuseppe; Munzenrieder, Niko; Daus, Alwin; Troster, Gerhard

2015-08-01

This paper presents the optimization of electronic circuitry for operation in the harsh electro magnetic (EM) environment during a magnetic resonance imaging (MRI) scan. As demonstrator, a device small enough to be worn during the scan is optimized. Based on finite element method (FEM) simulations, the induced current densities due to magnetic field changes of 200 T s(-1) were reduced from 1 × 10(10) A m(-2) by one order of magnitude, predicting error-free operation of the 1.8V logic employed. The simulations were validated using a bit error rate test, which showed no bit errors during a MRI scan sequence. Therefore, neither the logic, nor the utilized 800 Mbit s(-1) low voltage differential swing (LVDS) data link of the optimized wearable device were significantly influenced by the EM interference. Next, the influence of ferro-magnetic components on the static magnetic field and consequently the image quality was simulated showing a MRI image loss with approximately 2 cm radius around a commercial integrated circuit of 1×1 cm(2). This was successively validated by a conventional MRI scan.

An integrated optical sensor for GMAW feedback control

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

Taylor, P.L.; Watkins, A.D.; Larsen, E.D.

1992-08-01

The integrated optical sensor (IOS) is a multifunction feedback control sensor for arc welding, that is computer automated and independent of significant operator interaction. It is based on three major ``off-the-shelf`` components: a charged coupled device (CCD) camera, a diode laser, and a processing computer. The sensor head is compact and lightweight to avoid interference with weld head mobility, hardened to survive the harsh operating environment, and free of specialized cooling and power requirements. The sensor is positioned behind the GMAW torch and measures weld pool position and width, standoff distance, and postweld centerline cooling rate. Weld pool position andmore » width are used in a feedback loop, by the weld controller, to track the weld pool relative to the weld joint, thus allowing compensation for such phenomena as arc blow. Sensor stand off distance is used in a feedback loop to control the contact tip to base metal distance during the welding process. Cooling rate information is used to infer the final metallurgical state of the weld bead and heat affected zone, thereby providing a means of controlling post weld mechanical properties.« less

An integrated optical sensor for GMAW feedback control

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

Taylor, P.L.; Watkins, A.D.; Larsen, E.D.

1992-01-01

The integrated optical sensor (IOS) is a multifunction feedback control sensor for arc welding, that is computer automated and independent of significant operator interaction. It is based on three major off-the-shelf'' components: a charged coupled device (CCD) camera, a diode laser, and a processing computer. The sensor head is compact and lightweight to avoid interference with weld head mobility, hardened to survive the harsh operating environment, and free of specialized cooling and power requirements. The sensor is positioned behind the GMAW torch and measures weld pool position and width, standoff distance, and postweld centerline cooling rate. Weld pool position andmore » width are used in a feedback loop, by the weld controller, to track the weld pool relative to the weld joint, thus allowing compensation for such phenomena as arc blow. Sensor stand off distance is used in a feedback loop to control the contact tip to base metal distance during the welding process. Cooling rate information is used to infer the final metallurgical state of the weld bead and heat affected zone, thereby providing a means of controlling post weld mechanical properties.« less

Development of High Temperature Gas Sensor Technology

NASA Technical Reports Server (NTRS)

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

1997-01-01

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

Leveraging knowledge from physiological data: on-body heat stress risk prediction with sensor networks.

PubMed

Gaura, Elena; Kemp, John; Brusey, James

2013-12-01

The paper demonstrates that wearable sensor systems, coupled with real-time on-body processing and actuation, can enhance safety for wearers of heavy protective equipment who are subjected to harsh thermal environments by reducing risk of Uncompensable Heat Stress (UHS). The work focuses on Explosive Ordnance Disposal operatives and shows that predictions of UHS risk can be performed in real-time with sufficient accuracy for real-world use. Furthermore, it is shown that the required sensory input for such algorithms can be obtained with wearable, non-intrusive sensors. Two algorithms, one based on Bayesian nets and another on decision trees, are presented for determining the heat stress risk, considering the mean skin temperature prediction as a proxy. The algorithms are trained on empirical data and have accuracies of 92.1±2.9% and 94.4±2.1%, respectively when tested using leave-one-subject-out cross-validation. In applications such as Explosive Ordnance Disposal operative monitoring, such prediction algorithms can enable autonomous actuation of cooling systems and haptic alerts to minimize casualties.

Surface acoustic wave devices for sensor applications

NASA Astrophysics Data System (ADS)

Bo, Liu; Xiao, Chen; Hualin, Cai; Mohammad, Mohammad Ali; Xiangguang, Tian; Luqi, Tao; Yi, Yang; Tianling, Ren

2016-02-01

Surface acoustic wave (SAW) devices have been widely used in different fields and will continue to be of great importance in the foreseeable future. These devices are compact, cost efficient, easy to fabricate, and have a high performance, among other advantages. SAW devices can work as filters, signal processing units, sensors and actuators. They can even work without batteries and operate under harsh environments. In this review, the operating principles of SAW sensors, including temperature sensors, pressure sensors, humidity sensors and biosensors, will be discussed. Several examples and related issues will be presented. Technological trends and future developments will also be discussed. Project supported by the National Natural Science Foundation of China (Nos. 60936002, 61025021, 61434001, 61574083), the State Key Development Program for Basic Research of China (No. 2015CB352100), the National Key Project of Science and Technology (No. 2011ZX02403-002) and the Special Fund for Agroscientific Research in the Public Interest of China (No. 201303107). M.A.M is additionally supported by the Postdoctoral Fellowship (PDF) program of the Natural Sciences and Engineering Research Council (NSERC) of Canada and the China Postdoctoral Science Foundation (CPSF).

Demonstration and Science Experiment (DSX) Space Weather Experiment (SWx)

DTIC Science & Technology

2009-01-01

environment encountered by medium-earth orbits (MEO). at an altitude range from 6,000 to 15.000 km "’. The discovery of the earth’s radiation...forecast models that enable future space missions in the medium Earth orbit regime to enable better spacecraft designed to withstand the harsh environment...the size of the sensor and to exploit a compact layout. The inside spherical section has an attraction voltage and the outside section has the

Compact Full-Field Ion Detector System for CubeSat Science Beyond LEO

NASA Technical Reports Server (NTRS)

Wrbanek, John D.; Wrbanek, Susan Y.; Fralick, Gustave C.; Clark, Pamela E.

2013-01-01

NASA Glenn Research Center (GRC) is applying its expertise and facilities in harsh environment instrumentation to develop a Compact Full-Field Ion Detector System (CFIDS). The CFIDS is designed to be an extremely compact, low cost instrument, capable of being flown on a wide variety of deep space platforms, to provide comprehensive (composition, velocity, and direction) in situ measurements of heavy ions in space plasma environments with higher fidelity, than previously available.

Experimental validation of finite element model analysis of a steel frame in simulated post-earthquake fire environments

NASA Astrophysics Data System (ADS)

Huang, Ying; Bevans, W. J.; Xiao, Hai; Zhou, Zhi; Chen, Genda

2012-04-01

During or after an earthquake event, building system often experiences large strains due to shaking effects as observed during recent earthquakes, causing permanent inelastic deformation. In addition to the inelastic deformation induced by the earthquake effect, the post-earthquake fires associated with short fuse of electrical systems and leakage of gas devices can further strain the already damaged structures during the earthquakes, potentially leading to a progressive collapse of buildings. Under these harsh environments, measurements on the involved building by various sensors could only provide limited structural health information. Finite element model analysis, on the other hand, if validated by predesigned experiments, can provide detail structural behavior information of the entire structures. In this paper, a temperature dependent nonlinear 3-D finite element model (FEM) of a one-story steel frame is set up by ABAQUS based on the cited material property of steel from EN 1993-1.2 and AISC manuals. The FEM is validated by testing the modeled steel frame in simulated post-earthquake environments. Comparisons between the FEM analysis and the experimental results show that the FEM predicts the structural behavior of the steel frame in post-earthquake fire conditions reasonably. With experimental validations, the FEM analysis of critical structures could be continuously predicted for structures in these harsh environments for a better assistant to fire fighters in their rescue efforts and save fire victims.

The intensive DT neutron generator of TU Dresden

NASA Astrophysics Data System (ADS)

Klix, Axel; DÖring, Toralf; Domula, Alexander; Zuber, Kai

2018-01-01

TU Dresden operates an accelerator-based intensive DT neutron generator. Experimental activities comprise investigation into material activation and decay, neutron and photon transport in matter and R&D work on radiation detectors for harsh environments. The intense DT neutron generator is capable to produce a maximum of 1012 n/s. The neutron source is a solid-type water-cooled tritium target based on a titanium matrix on a copper carrier. The neutron yield at a typical deuteron beam current of 1 mA is of the order of 1011 n/s in 4Π. A pneumatic sample transport system is available for short-time irradiations and connected to wo high-purity germanium detector spectrometers for the measurement of induced activities. The overall design of the experimental hall with the neutron generator allows a flexible setup of experiments including the possibility of investigating larger structures and cooled samples or samples at high temperatures.

Reliability analysis and utilization of PEMs in space application

NASA Astrophysics Data System (ADS)

Jiang, Xiujie; Wang, Zhihua; Sun, Huixian; Chen, Xiaomin; Zhao, Tianlin; Yu, Guanghua; Zhou, Changyi

2009-11-01

More and more plastic encapsulated microcircuits (PEMs) are used in space missions to achieve high performance. Since PEMs are designed for use in terrestrial operating conditions, the successful usage of PEMs in space harsh environment is closely related to reliability issues, which should be considered firstly. However, there is no ready-made methodology for PEMs in space applications. This paper discusses the reliability for the usage of PEMs in space. This reliability analysis can be divided into five categories: radiation test, radiation hardness, screening test, reliability calculation and reliability assessment. One case study is also presented to illuminate the details of the process, in which a PEM part is used in a joint space program Double-Star Project between the European Space Agency (ESA) and China. The influence of environmental constrains including radiation, humidity, temperature and mechanics on the PEM part has been considered. Both Double-Star Project satellites are still running well in space now.

High Temperature Piezoelectric Drill

NASA Technical Reports Server (NTRS)

Bao, Xiaoqi; Bar-Cohen, Yoseph; Sherrit, Stewart; Badescu, Mircea; Shrout, Tom

2012-01-01

Venus is one of the planets in the solar systems that are considered for potential future exploration missions. It has extreme environment where the average temperature is 460 deg C and its ambient pressure is about 90 atm. Since the existing actuation technology cannot maintain functionality under the harsh conditions of Venus, it is a challenge to perform sampling and other tasks that require the use of moving parts. Specifically, the currently available electromagnetic actuators are limited in their ability to produce sufficiently high stroke, torque, or force. In contrast, advances in developing electro-mechanical materials (such as piezoelectric and electrostrictive) have enabled potential actuation capabilities that can be used to support such missions. Taking advantage of these materials, we developed a piezoelectric actuated drill that operates at the temperature range up to 500 deg C and the mechanism is based on the Ultrasonic/Sonic Drill/Corer (USDC) configuration. The detailed results of our study are presented in this paper

The research on thermal adaptability reinforcement technology for photovoltaic modules

NASA Astrophysics Data System (ADS)

Su, Nana; Zhou, Guozhong

2015-10-01

Nowadays, Photovoltaic module contains more high-performance components in smaller space. It is also demanded to work in severe temperature condition for special use, such as aerospace. As temperature rises, the failure rate will increase exponentially which makes reliability significantly reduce. In order to improve thermal adaptability of photovoltaic module, this paper makes a research on reinforcement technologies. Thermoelectric cooler is widely used in aerospace which has harsh working environment. So, theoretical formulas for computing refrigerating efficiency, refrigerating capacity and temperature difference are described in detail. The optimum operating current of three classical working condition is obtained which can be used to guide the design of driven circuit. Taken some equipment enclosure for example, we use thermoelectric cooler to reinforce its thermal adaptability. By building physical model and thermal model with the aid of physical dimension and constraint condition, the model is simulated by Flotherm. The temperature field cloud is shown to verify the effectiveness of reinforcement.

Design and assessment of a robust voltage amplifier with 2.5 GHz GBW and >100 kGy total dose tolerance

NASA Astrophysics Data System (ADS)

Verbeeck, J.; Leroux, P.; Steyaert, M.

2011-01-01

A differential voltage amplifier with a gain-bandwidth product of 2.5Ghz and using adaptive biasing has been designed in a standard CMOS technology and assessed under radiation and temperature variations. The principle used in this ASIC will be employed in the design of a Gbps TIA with improved tolerance for γ-irradiation and temperature for an optical instrumentation (LIDAR) receiver aiming at operation in harsh environments. The voltage amplifier was tested under gamma radiation and features a gain degradation of merely 4.5% up to a total dose of 100kGy. In order to verify the radiation effects on the IC, the threshold voltage shift of the separate transistors has been investigated. Temperature characterization has shown that the amplifier features a reduction of the voltage gain by only 5.6% for a temperature range of -40 till 130 °C.

Development of a Silicon Drift Detector Array: An X-Ray Fluorescence Spectrometer for Remote Surface Mapping

NASA Technical Reports Server (NTRS)

Gaskin, Jessica A.; Carini, Gabriella A.; Wei, Chen; Elsner, Ronald F.; Kramer, Georgiana; De Geronimo, Gianluigi; Keister, Jeffrey W.; Zheng, Li; Ramsey, Brian D.; Rehak, Pavel;

Exploring the effect of diffuse reflection on indoor localization systems based on RSSI-VLC.

PubMed

Mohammed, Nazmi A; Elkarim, Mohammed Abd

2015-08-10

This work explores and evaluates the effect of diffuse light reflection on the accuracy of indoor localization systems based on visible light communication (VLC) in a high reflectivity environment using a received signal strength indication (RSSI) technique. The effect of the essential receiver (Rx) and transmitter (Tx) parameters on the localization error with different transmitted LED power and wall reflectivity factors is investigated at the worst Rx coordinates for a directed/overall link. Since this work assumes harsh operating conditions (i.e., a multipath model, high reflectivity surfaces, worst Rx position), an error of ≥ 1.46 m is found. To achieve a localization error in the range of 30 cm under these conditions with moderate LED power (i.e., P = 0.45 W), low reflectivity walls (i.e., ρ = 0.1) should be used, which would enable a localization error of approximately 7 mm at the room's center.

Design and Operation of a Fast, Thin-Film Thermocouple Probe on a Turbine Engine

NASA Technical Reports Server (NTRS)

Meredith, Roger D.; Wrbanek, John D.; Fralick, Gustave C.; Greer, Lawrence C., III; Hunter, Gary W.; Chen, Liang-Yu

2014-01-01

As a demonstration of technology maturation, a thin-film temperature sensor probe was fabricated and installed on a F117 turbofan engine via a borescope access port to monitor the temperature experienced in the bleed air passage of the compressor area during an engine checkout test run. To withstand the harsh conditions experienced in this environment, the sensor probe was built from high temperature materials. The thin-film thermocouple sensing elements were deposited by physical vapor deposition using pure metal elements, thus avoiding the inconsistencies of sputter-depositing particular percentages of materials to form standardized alloys commonly found in thermocouples. The sensor probe and assembly were subjected to a strict protocol of multi-axis vibrational testing as well as elevated temperature pressure testing to be qualified for this application. The thin-film thermocouple probe demonstrated a faster response than a traditional embedded thermocouple during the engine checkout run.

State of the art in protection of erosion-corrosion on vertical axis tidal current turbine

NASA Astrophysics Data System (ADS)

Musabikha, Siti; Utama, I. Ketut Aria Pria; Mukhtasor

2018-05-01

Vertical axis tidal current turbine is main part of ocean energy devices which converts the tidal current energy into electricity. Its development is arising too due to increased interest research topic concerning climate change mitigation. Due to its rotating movement, it will be induced mechanical forces, such as shear stress and/or particle impact. Because of its natural operations, vertical axis turbine is also being exposed to harsh and corroding marine environment itself. In order to secure the vertical tidal turbine devices from mechanical wear and corrosion effects which is lead to a material loss, an appropriate erosion-corrosion protection needs to be defined. Its protection actionscan be derived such as design factors, material selections, inhibitors usage, cathodic protections, and coatings. This paper aims to analyze protection method which is necessary to control erosion-corrosion phenomenon that appears to the vertical axis tidal current turbine.

Real-Time Considerations for Rugged Embedded Systems

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

Tumeo, Antonino; Ceriani, Marco; Palermo, Gianluca

This chapter introduces the characterizing aspects of embedded systems, and discusses the specific features that a designer should address to an embedded system “rugged”, i.e., able to operate reliably in harsh environments. The chapter addresses both the hardware and the less obvious software aspect. After presenting a current list of certifications for ruggedization, the chapters present a case study that focuses on the interaction of the hardware and software layers in reactive real-time system. In particular, it shows how the use of fast FPGA prototyping could provide insights on unexpected factors that influence the performance and thus responsiveness to eventsmore » of a scheduling algorithm for multiprocessor systems that manages both periodic, hard real-time task, and aperiodic tasks. The main lesson is that to make the system “rugged”, a designer should consider these issues by, for example, overprovisioning resources and/or computation capabilities.« less

Nanopatched Graphene with Molecular Self-Assembly Toward Graphene-Organic Hybrid Soft Electronics.

PubMed

Kang, Boseok; Lee, Seong Kyu; Jung, Jaehyuck; Joe, Minwoong; Lee, Seon Baek; Kim, Jinsung; Lee, Changgu; Cho, Kilwon

2018-06-01

Increasing the mechanical durability of large-area polycrystalline single-atom-thick materials is a necessary step toward the development of practical and reliable soft electronics based on these materials. Here, it is shown that the surface assembly of organosilane by weak epitaxy forms nanometer-thick organic patches on a monolayer graphene surface and dramatically increases the material's resistance to harsh postprocessing environments, thereby increasing the number of ways in which graphene can be processed. The nanopatched graphene with the improved mechanical durability enables stable operation when used as transparent electrodes of wearable strain sensors. Also, the nanopatched graphene applied as an electrode modulates the molecular orientation of deposited organic semiconductor layers, and yields favorable nominal charge injection for organic transistors. These results demonstrate the potential for use of self-assembled organic nanopatches in graphene-based soft electronics. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Detection of Artificially Generated Seismic Signals Using Balloon-Borne Infrasound Sensors

DOE PAGES

Krishnamoorthy, Siddharth; Komjathy, Attila; Pauken, Michael T.; ...

2018-04-24

Here, we conducted an experiment in Pahrump, Nevada, in June 2017, where artificial seismic signals were created using a seismic hammer, and the possibility of detecting them from their acoustic signature was examined. In this work, we analyze the pressure signals recorded by highly sensitive barometers deployed on the ground and on tethers suspended from balloons. Our signal processing results show that wind noise experienced by a barometer on a free-flying balloon is lower compared to one on a moored balloon. This has never been experimentally demonstrated in the lower troposphere. While seismoacoustic signals were not recorded on the hotmore » air balloon platform owing to operational challenges, we demonstrate the detection of seismoacoustic signals on our moored balloon platform. Our results have important implications for performing seismology in harsh surface environments such as Venus through atmospheric remote sensing.« less

A Fiber-Optic Probe Design for Combustion Chamber Flame Detection Applications-Design Criteria, Performance Specifications, and Fabrication Technique

NASA Technical Reports Server (NTRS)

Borg, Stephen E.; Harper, Samuel E.

2001-01-01

This paper documents the design and development of the fiber-optic probes utilized in the flame detection systems used in NASA Langley Research Center's 8-Foot High Temperature Tunnel (8-ft HTT). Two independent flame detection systems are utilized to monitor the presence and stability of the main-burner and pilot-level flames during facility operation. Due to the harsh environment within the combustor, the successful development of a rugged and efficient fiber-optic probe was a critical milestone in the development of these flame detection systems. The final optical probe design for the two flame detection systems resulted from research that was conducted in Langley's 7-in High Temperature Pilot Tunnel (7-in HTT). A detailed description of the manufacturing process behind the optical probes used in the 8-ft HTT is provided in Appendix A of this report.

Environmental monitoring using autonomous vehicles: a survey of recent searching techniques.

PubMed

Bayat, Behzad; Crasta, Naveena; Crespi, Alessandro; Pascoal, António M; Ijspeert, Auke

2017-06-01

Autonomous vehicles are becoming an essential tool in a wide range of environmental applications that include ambient data acquisition, remote sensing, and mapping of the spatial extent of pollutant spills. Among these applications, pollution source localization has drawn increasing interest due to its scientific and commercial interest and the emergence of a new breed of robotic vehicles capable of operating in harsh environments without human supervision. The aim is to find the location of a region that is the source of a given substance of interest (e.g. a chemical pollutant at sea or a gas leakage in air) using a group of cooperative autonomous vehicles. Motivated by fast paced advances in this challenging area, this paper surveys recent advances in searching techniques that are at the core of environmental monitoring strategies using autonomous vehicles. Copyright © 2017 Elsevier Ltd. All rights reserved.

Performance of Surface-Mount Ceramic and Solid Tantalum Capacitors for Cryogenic Applications

NASA Technical Reports Server (NTRS)

Patterson, Richard L.; MacDonald, Thomas L.; Hammoud, Ahmad; Gerber, Scott

1998-01-01

Low temperature electronics are of great interest for space exploration programs. These include missions to the outer planets, earth-orbiting and deep-space probes, remote-sensing and communication satellites. Terrestrial applications would also benefit from the availability of low temperature electronics. Power components capable of low temperature operation would, thus, enhance the technologies needed for the development of advanced power systems suitable for use in harsh environments. In this work, ceramic and solid tantalum capacitors were evaluated in terms of their dielectric properties as a function of temperature and at various frequencies. The surface-mount devices were characterized in terms of their capacitance stability and dissipation factor in the frequency range of 50 Hz to 100 kHz at temperatures ranging from room temperature (20 deg. C) to about liquid nitrogen temperature (-190 deg. C). The results are discussed and conclusions made concerning the suitability of the capacitors investigated for low temperature applications.

Optimization study on the primary mirror lightweighting of a remote sensing instrument

NASA Astrophysics Data System (ADS)

Chan, Chia-Yen; Huang, Bo-Kai; You, Zhen-Ting; Chen, Yi-Cheng; Huang, Ting-Ming

2015-07-01

Remote sensing instrument (RSI) is used to take images for ground surface observation, which will be exposed to high vacuum, high temperature difference, gravity, 15 g-force and random vibration conditions and other harsh environments during operation. While designing a RSI optical system, not only the optical quality but also the strength of mechanical structure we should be considered. As a result, an optimization method is adopted to solve this engineering problem. In the study, a ZERODUR® mirror with a diameter of 466 mm has been chosen as the model and the optimization has been executed by combining the computer-aided design, finite element analysis, and parameter optimization software. The optimization is aimed to obtain the most lightweight mirror with maintaining structural rigidity and good optical quality. Finally, the optimum optical mirror with a lightweight ratio of 0.55 is attained successfully.

A physical model of the photo- and radiation-induced degradation of ytterbium-doped silica optical fibres

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

Mady, Franck, E-mail: franck.mady@unice.fr; Duchez, Jean-Bernard, E-mail: franck.mady@unice.fr; Mebrouk, Yasmine, E-mail: franck.mady@unice.fr

2014-10-21

We propose a model to describe the photo- or/and the radiation-induced darkening of ytterbium-doped silica optical fibers. This model accounts for the well-established experimental features of photo-darkening. Degradation behaviors predicted for fibers pumped in harsh environments are also fully confirmed by experimental data reported in the work by Duchez et al. (this proceeding), which gives a detailed characterization of the interplay between the effects of the pump and those of a superimposed ionizing irradiation (actual operation conditions in space-based applications for instance). In particular, dependences of the darkening build-up on the pump power, the total ionizing dose and the dosemore » rate are all correctly reproduced. The presented model is a ‘sufficient’ one, including the minimal physical ingredients required to reproduce experimental features. Refinements could be proposed to improve, e.g., quantitative kinetics.« less

Gas turbine coatings eddy current quantitative and qualitative evaluation

NASA Astrophysics Data System (ADS)

Ribichini, Remo; Giolli, Carlo; Scrinzi, Erica

2017-02-01

Gas turbine blades (buckets) are among the most critical and expensive components of the engine. Buckets rely on protective coatings in order to withstand the harsh environment in which they operate. The thickness and the microstructure of coatings during the lifespan of a unit are fundamental to evaluate their fitness for service. A frequency scanning Eddy Current instrument can allow the measurement of the thickness and of physical properties of coatings in a Non-Destructive manner. The method employed relies on the acquisition of impedance spectra and on the inversion of the experimental data to derive the coating properties and structure using some assumptions. This article describes the experimental validation performed on several samples and real components in order to assess the performance of the instrument as a coating thickness gage. The application of the technique to support residual life assessment of serviced buckets is also presented.

Thermally and chemically responsive nanoporous materials for efficient capture of fission product gases.

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

Stroeve, Pieter; Faller, Roland

The objective of this project was to develop robust, high-efficiency materials for capture of fission product gases such as He, Xe and Kr in scenarios relevant for both reactor fuels and reprocessing operations. The relevant environments are extremely harsh, encompassing temperatures up to 1500 °C, high levels of radiation, as well as potential exposures to highly-reactive chemicals such as nitric acid and organic solvents such as kerosene. The requirement for nanostructured capture materials is driven in part by the very short (few micron) diffusion distances for product gases in nuclear fuel. We achieved synthesis, characterization and detailed modeling of themore » materials. Although not all materials reviewed in this report will be feasible for the ultimate goal of integration in nuclear fuel, nevertheless each material studied has particular properties which will enable an optimized material to be efficiently developed and characterized.« less

Progress Towards the Development of a Long-Lived Venus Lander Duplex System

NASA Technical Reports Server (NTRS)

Dyson, Roger W.; Bruder, Geoffrey A.

2010-01-01

NASA has begun the development of a combined Stirling cycle power and cooling system (duplex) to enable the long-lived surface exploration of Venus and other harsh environments in the solar system. The duplex system will operate from the heat provided by decaying radioisotope plutonium-238 or its substitute. Since the surface of Venus has a thick, hot, and corrosive atmosphere, it is a challenging proposition to maintain sensitive lander electronics under survivable conditions. This development effort requires the integration of: a radioisotope or fission heat source; heat pipes; high-temperature, corrosion-resistant material; multistage cooling; a novel free-displacer Stirling convertor for the lander; and a minimal vibration thermoacoustic Stirling convertor for the seismometer. The first year effort includes conceptual system design and control studies, materials development, and prototype hardware testing. A summary of these findings and test results is presented in this report.

Environmental and forensic applications of field-portable GC-MS: an overview.

PubMed

Eckenrode, B A

2001-06-01

GC-MS can provide analytical information that is most reliable for many types of organic analyses. As field-portable GC-MS analytical systems evolve, the application scenarios have diversified as well. With the development of rugged fieldable systems, these instruments were demonstrated to be usable in the harsh environment of the jungle and in chemical demilitarization or military reconnaissance situations. Continuous unattended operations of a GC-MS for 12- or 24-hour monitoring applications in the field have been shown to be possible. A real-time algorithm strategy is proposed, which can be developed to aid in the advancement of field-portable mass spectrometry applied to chemical warfare agent analysis in military vehicles and can be used to raise the standard for field data quality. Each of these capabilities is discussed with the intent on reviewing analysis situations that can be expanded because of developments in field GC-MS instrumentation.

Progress Towards the Development of a Long-Lived Venus Lander Duplex System

NASA Technical Reports Server (NTRS)

Dyson, Rodger, W.; Bruder, Geoffrey A.

2011-01-01

NASA has begun the development of a combined Stirling cycle power and cooling system (duplex) to enable the long-lived surface exploration of Venus and other harsh environments in the solar system. The duplex system will operate from the heat provided by decaying radioisotope plutonium-238 or its substitute. Since the surface of Venus has a thick, hot, and corrosive atmosphere, it is a challenging proposition to maintain sensitive lander electronics under survivable conditions. This development effort requires the integration of: a radioisotope or fission heat source; heat pipes; high-temperature, corrosion-resistant material; multistage cooling; a novel free-displacer Stirling convertor for the lander; and a minimal vibration thermoacoustic Stirling convertor for the seismometer. The first year effort includes conceptual system design and control studies, materials development, and prototype hardware testing. A summary of these findings and test results is presented in this report.

Detection of Artificially Generated Seismic Signals Using Balloon-Borne Infrasound Sensors

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

Krishnamoorthy, Siddharth; Komjathy, Attila; Pauken, Michael T.

Here, we conducted an experiment in Pahrump, Nevada, in June 2017, where artificial seismic signals were created using a seismic hammer, and the possibility of detecting them from their acoustic signature was examined. In this work, we analyze the pressure signals recorded by highly sensitive barometers deployed on the ground and on tethers suspended from balloons. Our signal processing results show that wind noise experienced by a barometer on a free-flying balloon is lower compared to one on a moored balloon. This has never been experimentally demonstrated in the lower troposphere. While seismoacoustic signals were not recorded on the hotmore » air balloon platform owing to operational challenges, we demonstrate the detection of seismoacoustic signals on our moored balloon platform. Our results have important implications for performing seismology in harsh surface environments such as Venus through atmospheric remote sensing.« less

Whole cell biocatalysts: essential workers from Nature to the industry.

PubMed

de Carvalho, Carla C C R

2017-03-01

Microorganisms have been exposed to a myriad of substrates and environmental conditions throughout evolution resulting in countless metabolites and enzymatic activities. Although mankind have been using these properties for centuries, we have only recently learned to control their production, to develop new biocatalysts with high stability and productivity and to improve their yields under new operational conditions. However, microbial cells still provide the best known environment for enzymes, preventing conformational changes in the protein structure in non-conventional medium and under harsh reaction conditions, while being able to efficiently regenerate necessary cofactors and to carry out cascades of reactions. Besides, a still unknown microbe is probably already producing a compound that will cure cancer, Alzeihmer's disease or kill the most resistant pathogen. In this review, the latest developments in screening desirable activities and improving production yields are discussed. © 2016 The Author. Microbial Biotechnology published by John Wiley & Sons Ltd and Society for Applied Microbiology.

Evaluation of internal boiler components and gases using a high-temperature infrared (IR) lens

NASA Astrophysics Data System (ADS)

Hammaker, Robert G.; Colsher, Richard J.; Miles, Jonathan J.; Madding, Robert P.

1996-03-01

Fuel accounts for an average of seventy percent of the yearly operational and maintenance costs of all the fossil stations in the United States. This amounts to 30 billion dollars spent for fuel each year. In addition, federal and state environmental codes have been enforcing stricter regulations that demand cleaner environments, such as the reduction of nitrogen oxides (NOx), which are a by-product of the fossil fuel flame. If the burn of the flame inside a boiler could be optimized, the usage of fuel and the amounts of pollution produced would be significantly reduced, and many of the common boiler tube failures can be avoided. This would result in a major dollar savings to the utility industry, and would provide a cleaner environment. Accomplishing these goals will require a major effort from the designers and operators that manufacture, operate, and maintain the fossil stations. Over the past few years re-designed burners have been installed in many boilers to help control the temperatures and shape of the flame for better performance and NOx reduction. However, the measurement of the processes and components inside the furnace, that could assist in determining the desired conditions, can at times be very difficult due to the hostile hot environment. In an attempt to resolve these problems, the EPRI M&D Center and a core group of EPRI member utilities have undertaken a two-year project with various optical manufacturers, IR manufacturers, and IR specialists, to fully develop an optical lens that will withstand the high furnace temperatures. The purpose of the lens is to explore the possibilities of making accurate high temperature measurements of the furnace processes and components in an ever-changing harsh environment. This paper provides an introduction to EPRI's internal boiler investigation using an IR high temperature lens (HTL). The paper describes the objectives, approach, benefits, and project progress.

Translocation of botulinum neurotoxin serotype a and associated proteins across the intestinal epithelia

USDA-ARS?s Scientific Manuscript database

Botulinum neurotoxins (BoNTs) are some of the most poisonous natural toxins and considered to be a major venue of bioterrorist threat. BoNTs associate with neurotoxin associated proteins (NAPs), forming large complexes. NAPs have been shown to shield the BoNT holotoxin from the harsh environment of ...

A Harsh and Challenging World of Work: Implications for Counselors.

ERIC Educational Resources Information Center

Jones, Lawrence K.

1996-01-01

Presents some of the health risks and economic and job insecurities involved in working in the United States. Suggests ways for counselors to amend their practices to accommodate the changing work environment and to help clients prepare for and deal with the economic and physical realities of the job market. (Author)

Novel insights into the Elm Yellows phytoplasma genome and into the metagenome of Elm Yellows-infected elms

USDA-ARS?s Scientific Manuscript database

In North America, American elms were historically present throughout the northeastern United States and southeastern Canada. The longevity of these trees, their resistance to the harsh urban environment, and their aesthetics led to their wide use in landscaping and streetscaping over several decade...

To Please the Animal Master: The Innu Hunting Way of Life.

ERIC Educational Resources Information Center

Loring, Stephen

1996-01-01

Examines the ways in which the Innu people interact with the flora and fauna of their lands in northern Quebec and Labrador, Canada. Describes Innu methods for adapting to the harsh environment and discusses their folkways regarding the hunting of and preparation of meals made from local animals. (MAB)

Spacer engineered Trigate SOI TFET: An investigation towards harsh temperature environment applications

NASA Astrophysics Data System (ADS)

Mallikarjunarao; Ranjan, Rajeev; Pradhan, K. P.; Artola, L.; Sahu, P. K.

2016-09-01

In this paper, a novel N-channel Tunnel Field Effect Transistor (TFET) i.e., Trigate Silicon-ON-Insulator (SOI) N-TFET with high-k spacer is proposed for better Sub-threshold swing (SS) and OFF-state current (IOFF) by keeping in mind the sensitivity towards temperature. The proposed model can achieve a Sub-threshold swing less than 35 mV/decade at various temperatures, which is desirable for designing low power CTFET for digital circuit applications. In N-TFET source doping has a significant effect on the ON-state current (ION) level; therefore more electrons will tunnel from source to channel region. High-k Spacer i.e., HfO2 is used to enhance the device performance and also it avoids overlapping of transistors in an integrated circuits (IC's). We have designed a reliable device by performing the temperature analysis on Transfer characteristics, Drain characteristics and also on various performance metrics like ON-state current (ION), OFF-state current (IOFF), ION/IOFF, Trans-conductance (gm), Trans-conductance Generation Factor (TGF), Sub-threshold Swing (SS) to observe the applications towards harsh temperature environment.

Hypersonic force measurements using internal balance based on optical micromachined Fabry-Perot interferometry.

PubMed

Qiu, Huacheng; Min, Fu; Zhong, Shaolong; Song, Xin; Yang, Yanguang

2018-03-01

Force measurements using wind tunnel balance are necessary for determining a variety of aerodynamic performance parameters, while the harsh environment in hypersonic flows requires that the measurement instrument should be reliable and robust, in against strong electromagnetic interference, high vacuum, or metal (oxide) dusts. In this paper, we demonstrated a three-component internal balance for hypersonic aerodynamic force measurements, using novel optical micromachined Fabry-Perot interferometric (FPI) strain gauges as sensing elements. The FPI gauges were fabricated using Micro-Opto-Electro-Mechanical Systems (MOEMS) surface and bulk fabrication techniques. High-reflectivity coatings are used to form a high-finesse Fabry-Perot cavity, which benefits a high resolution. Antireflective and passivation coatings are used to reduce unwanted interferences. The FPI strain gauge based balance has been calibrated and evaluated in a Mach 5 hypersonic flow. The results are compared with the traditional technique using the foil resistive strain gauge balance, indicating that the proposed balance based on the MOEMS FPI strain gauge is reliable and robust and is potentially suitable for the hypersonic wind tunnel harsh environment.

Hypersonic force measurements using internal balance based on optical micromachined Fabry-Perot interferometry

NASA Astrophysics Data System (ADS)

Qiu, Huacheng; Min, Fu; Zhong, Shaolong; Song, Xin; Yang, Yanguang

2018-03-01

Force measurements using wind tunnel balance are necessary for determining a variety of aerodynamic performance parameters, while the harsh environment in hypersonic flows requires that the measurement instrument should be reliable and robust, in against strong electromagnetic interference, high vacuum, or metal (oxide) dusts. In this paper, we demonstrated a three-component internal balance for hypersonic aerodynamic force measurements, using novel optical micromachined Fabry-Perot interferometric (FPI) strain gauges as sensing elements. The FPI gauges were fabricated using Micro-Opto-Electro-Mechanical Systems (MOEMS) surface and bulk fabrication techniques. High-reflectivity coatings are used to form a high-finesse Fabry-Perot cavity, which benefits a high resolution. Antireflective and passivation coatings are used to reduce unwanted interferences. The FPI strain gauge based balance has been calibrated and evaluated in a Mach 5 hypersonic flow. The results are compared with the traditional technique using the foil resistive strain gauge balance, indicating that the proposed balance based on the MOEMS FPI strain gauge is reliable and robust and is potentially suitable for the hypersonic wind tunnel harsh environment.

Drag reduction using metallic engineered surfaces with highly ordered hierarchical topographies: nanostructures on micro-riblets

NASA Astrophysics Data System (ADS)

Kim, Taekyung; Shin, Ryung; Jung, Myungki; Lee, Jinhyung; Park, Changsu; Kang, Shinill

2016-03-01

Durable drag-reduction surfaces have recently received much attention, due to energy-saving and power-consumption issues associated with harsh environment applications, such as those experienced by piping infrastructure, ships, aviation, underwater vehicles, and high-speed ground vehicles. In this study, a durable, metallic surface with highly ordered hierarchical structures was used to enhance drag-reduction properties, by combining two passive drag-reduction strategies: an air-layer effect induced by nanostructures and secondary vortex generation by micro-riblet structures. The nanostructures and micro-riblet structures were designed to increase slip length. The top-down fabrication method used to form the metallic hierarchical structures combined laser interference lithography, photolithography, thermal reflow, nanoimprinting, and pulse-reverse-current electrochemical deposition. The surfaces were formed from nickel, which has high hardness and corrosion resistance, making it suitable for use in harsh environments. The drag-reduction properties of various metal surfaces were investigated based on the surface structure: a bare surface, a nanostructured surface, a micro-riblet surface, and a hierarchically structured surface of nanostructures on micro-riblets.

Solar-Blind Photodetectors for Harsh Electronics

PubMed Central

Tsai, Dung-Sheng; Lien, Wei-Cheng; Lien, Der-Hsien; Chen, Kuan-Ming; Tsai, Meng-Lin; Senesky, Debbie G.; Yu, Yueh-Chung; Pisano, Albert P.; He, Jr-Hau

2013-01-01

We demonstrate solar-blind photodetectors (PDs) by employing AlN thin films on Si(100) substrates with excellent temperature tolerance and radiation hardness. Even at a bias higher than 200 V the AlN PDs on Si show a dark current as low as ~ 1 nA. The working temperature is up to 300°C and the radiation tolerance is up to 1013 cm−2 of 2-MeV proton fluences for AlN metal-semiconductor-metal (MSM) PDs. Moreover, the AlN PDs show a photoresponse time as fast as ~ 110 ms (the rise time) and ~ 80 ms (the fall time) at 5 V bias. The results demonstrate that AlN MSM PDs hold high potential in next-generation deep ultraviolet PDs for use in harsh environments. PMID:24022208

Chemochromic Hydrogen Sensors

NASA Technical Reports Server (NTRS)

Wiggins, Bryan C.

2007-01-01

As fossil fuel supplies decline, hydrogen is quickly becoming an increasingly important fuel source. Currently hydrogen is the prime fuel of today's space vehicles (e.g., Space Shuttle) and featured as a fuel for some prototype vehicles such as the BMW seven series model. Hydrogen is a colorless, odorless gas with a 4% lower explosive limit which makes leak detection a priority. In an effort to support the use of hydrogen, a chemochromic (color changing) sensor was developed that is robust, simple to use, and does not require active operation. It can be made into a thin tape which can be conveniently used for leak detection at flanges, valves, or outlets. Chemochromic sensors can be either reversible or irreversible; however, irreversible chemochromic sensors will be analyzed in this report. The irreversible sensor is useful during hazardous operations when personnel cannot be present. To actively monitor leaks, testing of the irreversible sensor against environmental effects was completed and results indicated this material is suitable for outdoor use in the harsh beachside environment of Kennedy Space Center. The experiments in this report will give additional results to the environmental testing by adding solid rocket booster residue as a variable. The primary motivation for these experiments is to prepare the sensors for the launch pad environment at the Kennedy Space Center. In an effort to simulate the atmosphere at the pads before and after launch, the chemochromic sensors are exposed to solid rocket residue under various conditions.

Macroevolutionary patterns of glucosinolate defense and tests of defense-escalation and resource availability hypotheses.

PubMed

Cacho, N Ivalú; Kliebenstein, Daniel J; Strauss, Sharon Y

2015-11-01

We explored macroevolutionary patterns of plant chemical defense in Streptanthus (Brassicaceae), tested for evolutionary escalation of defense, as predicted by Ehrlich and Raven's plant-herbivore coevolutionary arms-race hypothesis, and tested whether species inhabiting low-resource or harsh environments invest more in defense, as predicted by the resource availability hypothesis (RAH). We conducted phylogenetically explicit analyses using glucosinolate profiles, soil nutrient analyses, and microhabitat bareness estimates across 30 species of Streptanthus inhabiting varied environments and soils. We found weak to moderate phylogenetic signal in glucosinolate classes and no signal in total glucosinolate production; a trend toward evolutionary de-escalation in the numbers and diversity of glucosinolates, accompanied by an evolutionary increase in the proportion of aliphatic glucosinolates; some support for the RAH relative to soil macronutrients, but not relative to serpentine soil use; and that the number of glucosinolates increases with microhabitat bareness, which is associated with increased herbivory and drought. Weak phylogenetic signal in chemical defense has been observed in other plant systems. A more holistic approach incorporating other forms of defense might be necessary to confidently reject escalation of defense. That defense increases with microhabitat bareness supports the hypothesis that habitat bareness is an underappreciated selective force on plants in harsh environments. © 2015 The Authors. New Phytologist © 2015 New Phytologist Trust.

Implementation of a Non-Metallic Barrier in an Electric Motor

NASA Technical Reports Server (NTRS)

M?Sadoques, George; Carra, Michael; Beringer, Woody

2012-01-01

Electric motors that run in pure oxygen must be sealed, or "canned," for safety reasons to prevent the oxygen from entering into the electrical portion of the motor. The current canning process involves designing a metallic barrier around the rotor to provide the separation. This metallic barrier reduces the motor efficiency as speed is increased. In higher-speed electric motors, efficiency is greatly improved if a very thin, nonmetallic barrier can be utilized. The barrier thickness needs to be approximately 0.025-in. (.0.6-mm) thick and can be made of a brittle material such as glass. The motors, however, designed for space applications are typically subject to high-vibration environments. A fragile, non-metallic barrier can be utilized in a motor assembly if held in place by a set of standard rubber O-ring seals. The O-rings provide the necessary sealing to keep oxygen away from the electrical portion of the motor and also isolate the fragile barrier from the harsh motor vibration environment. The compliance of the rubber O-rings gently constrains the fragile barrier and isolates it from the harsh external motor environment. The use of a non-metallic barrier greatly improves motor performance, especially at higher speeds, while isolating the electronics from the working fluid with an inert liner.

Going Solar in Green Schools

ERIC Educational Resources Information Center

Domine, Mark

2011-01-01

These are tough economic times, and few groups are more cognizant of this than school and university administrators. Struggling with significantly smaller operating budgets, institutions are faced with the harsh realities of laying off qualified teachers and staff, increasing class sizes, limiting or eliminating valuable programs and, in some…

Village Stability Operations in Afghanistan: Comparing Past Counterinsurgencies for Future Applications

DTIC Science & Technology

2013-12-13

customs , forbid looting, and destruction of private property. Any violations by Americans resulted in harsh punishment. Every attempt was made to...British rule, although their loyalties remained with the Sultans who possessed limited power in government of the states. The Muslim Malays’ population

Research and development program in fiber optic sensors and distributed sensing for high temperature harsh environment energy applications (Conference Presentation)

NASA Astrophysics Data System (ADS)

Romanosky, Robert R.

2017-05-01

he National Energy Technology Laboratory (NETL) under the Department of Energy (DOE) Fossil Energy (FE) Program is leading the effort to not only develop near zero emission power generation systems, but to increaser the efficiency and availability of current power systems. The overarching goal of the program is to provide clean affordable power using domestic resources. Highly efficient, low emission power systems can have extreme conditions of high temperatures up to 1600 oC, high pressures up to 600 psi, high particulate loadings, and corrosive atmospheres that require monitoring. Sensing in these harsh environments can provide key information that directly impacts process control and system reliability. The lack of suitable measurement technology serves as a driver for the innovations in harsh environment sensor development. Advancements in sensing using optical fibers are key efforts within NETL's sensor development program as these approaches offer the potential to survive and provide critical information about these processes. An overview of the sensor development supported by the National Energy Technology Laboratory (NETL) will be given, including research in the areas of sensor materials, designs, and measurement types. New approaches to intelligent sensing, sensor placement and process control using networked sensors will be discussed as will novel approaches to fiber device design concurrent with materials development research and development in modified and coated silica and sapphire fiber based sensors. The use of these sensors for both single point and distributed measurements of temperature, pressure, strain, and a select suite of gases will be addressed. Additional areas of research includes novel control architecture and communication frameworks, device integration for distributed sensing, and imaging and other novel approaches to monitoring and controlling advanced processes. The close coupling of the sensor program with process modeling and control will be discussed for the overarching goal of clean power production.

Early Determinants of Maternal and Paternal Harsh Discipline: The Generation R Study

ERIC Educational Resources Information Center

Jansen, Pauline W.; Raat, Hein; Mackenbach, Johan P.; Hofman, Albert; Jaddoe, Vincent W. V.; Bakermans-Kranenburg, M. J.; van IJzendoorn, M. H.; Verhulst, Frank C.; Tiemeier, Henning

2012-01-01

Research described risk factors for maternal use of harsh discipline, but knowledge about determinants of paternal harsh discipline is lacking. This study aimed to identify determinants of harsh discipline and whether this differed between mothers and fathers. Harsh disciplining practices were self-reported by Dutch parents of 3-year-old children.…

Inflatable Habitat Health Monitoring: Implementation, Lessons Learned, and Application to Lunar or Martian Habitat Health Monitoring

NASA Technical Reports Server (NTRS)

Rojdev, Kristina; Hong, Todd; Hafermalz, Scott; Hunkins, Robert; Valle, Gerald; Toups, Larry

2009-01-01

NASA's exploration mission is to send humans to the Moon and Mars, in which the purpose is to learn how to live and work safely in those harsh environments. A critical aspect of living in an extreme environment is habitation, and within that habitation element there are key systems which monitor the habitation environment to provide a safe and comfortable living and working space for humans. Expandable habitats are one of the options currently being considered due to their potential mass and volume efficiencies. This paper discusses a joint project between the National Science Foundation (NSF), ILC Dover, and NASA in which an expandable habitat was deployed in the extreme environment of Antarctica to better understand the performance and operations over a one-year period. This project was conducted through the Innovative Partnership Program (IPP) where the NSF provided the location at McMurdo Station in Antarctica and support at the location, ILC Dover provided the inflatable habitat, and NASA provided the instrumentation and data system for monitoring the habitat. The outcome of this project provided lessons learned in the implementation of an inflatable habitat and the systems that support that habitat. These lessons learned will be used to improve current habitation capabilities and systems to meet the objectives of exploration missions to the moon and Mars.

Long-Term Reliability of a Hard-Switched Boost Power Processing Unit Utilizing SiC Power MOSFETs

NASA Technical Reports Server (NTRS)

Ikpe, Stanley A.; Lauenstein, Jean-Marie; Carr, Gregory A.; Hunter, Don; Ludwig, Lawrence L.; Wood, William; Iannello, Christopher J.; Del Castillo, Linda Y.; Fitzpatrick, Fred D.; Mojarradi, Mohammad M.;

Sample Handling in Extreme Environments

NASA Technical Reports Server (NTRS)

Avellar, Louisa; Badescu, Mircea; Sherrit, Stewart; Bar-Cohen, Yoseph

2013-01-01

Harsh environments, such as that on Venus, preclude the use of existing equipment for functions that involve interaction with the environment. The operating limitations of current high temperature electronics are well below the actual temperature and pressure found on Venus (460 deg C and 92 atm), so proposed lander configurations typically include a pressure vessel where the science instruments are kept at Earth-like temperature and pressure (25 deg C and 1 atm). The purpose of this project was to develop and demonstrate a method for sample transfer from an external drill to internal science instruments for a lander on Venus. The initial concepts were string and pneumatically driven systems; and the latter system was selected for its ability to deliver samples at very high speed. The pneumatic system was conceived to be driven by the pressure difference between the Venusian atmosphere and the inside of the lander. The pneumatic transfer of a small capsule was demonstrated, and velocity data was collected from the lab experiment. The sample transfer system was modeled using CAD software and prototyped using 3D printing. General structural and thermal analyses were performed to approximate the proposed system's mass and effects on the temperature and pressure inside of the lander. Additionally, a sampler breadboard for use on Titan was tested and functionality problems were resolved.

Solar Sail Propulsion Technology at NASA

NASA Technical Reports Server (NTRS)

Johnson, Charles Les

2007-01-01

NASA's In-Space Propulsion Technology Program developed the first generation of solar sail propulsion systems sufficient to accomplish inner solar system science and exploration missions. These first generation solar sails, when operational, will range in size from 40 meters to well over 100 meters in diameter and have an area density of less than 13 grams per square meter. A rigorous, multi-year technology development effort culminated in 2005 with the testing of two different 20-m solar sail systems under thermal vacuum conditions. This effort provided a number of significant insights into the optimal design and expected performance of solar sails as well as an understanding of the methods and costs of building and using them. In addition, solar sail orbital analysis tools for mission design were developed and tested. Laboratory simulations of the effects of long-term space radiation exposure were also conducted on two candidate solar sail materials. Detailed radiation and charging environments were defined for mission trajectories outside the protection of the earth's magnetosphere, in the solar wind environment. These were used in other analytical tools to prove the adequacy of sail design features for accommodating the harsh space environment. The presentation will describe the status of solar sail propulsion within NASA, near-term solar sail mission applications, and near-term plans for further development.

Damping control of micromachined lowpass mechanical vibration isolation filters using electrostatic actuation with electronic signal processing

NASA Astrophysics Data System (ADS)

Dean, Robert; Flowers, George; Sanders, Nicole; MacAllister, Ken; Horvath, Roland; Hodel, A. S.; Johnson, Wayne; Kranz, Michael; Whitley, Michael

2005-05-01

Some harsh environments, such as those encountered by aerospace vehicles and various types of industrial machinery, contain high frequency/amplitude mechanical vibrations. Unfortunately, some very useful components are sensitive to these high frequency mechanical vibrations. Examples include MEMS gyroscopes and resonators, oscillators and some micro optics. Exposure of these components to high frequency mechanical vibrations present in the operating environment can result in problems ranging from an increased noise floor to component failure. Passive micromachined silicon lowpass filter structures (spring-mass-damper) have been demonstrated in recent years. However, the performance of these filter structures is typically limited by low damping (especially if operated in near-vacuum environments) and a lack of tunability after fabrication. Active filter topologies, such as piezoelectric, electrostrictive-polymer-film and SMA have also been investigated in recent years. Electrostatic actuators, however, are utilized in many micromachined silicon devices to generate mechanical motion. They offer a number of advantages, including low power, fast response time, compatibility with silicon micromachining, capacitive position measurement and relative simplicity of fabrication. This paper presents an approach for realizing active micromachined mechanical lowpass vibration isolation filters by integrating an electrostatic actuator with the micromachined passive filter structure to realize an active mechanical lowpass filter. Although the electrostatic actuator can be used to adjust the filter resonant frequency, the primary application is for increasing the damping to an acceptable level. The physical size of these active filters is suitable for use in or as packaging for sensitive electronic and MEMS devices, such as MEMS vibratory gyroscope chips.

Robots Explore the Farthest Reaches of Earth and Space

NASA Technical Reports Server (NTRS)

2008-01-01

"We were the first that ever burst/Into that silent sea," the title character recounts in Samuel Taylor Coleridge s opus Rime of the Ancient Mariner. This famous couplet is equally applicable to undersea exploration today as surface voyages then, and has recently been applied to space travel in the title of a chronicle of the early years of human space flight ("Into That Silent Sea: Trailblazers of the Space Era, 1961-1965"), companion to the +n the Shadow of the Moon book and movie. The parallel is certainly fitting, considering both fields explore unknown, harsh, and tantalizingly inhospitable environments. For starters, exploring the Briny Deep and the Final Frontier requires special vehicles, and the most economical and safest means for each employ remotely operated vehicles (ROVs). ROVs have proven the tool of choice for exploring remote locations, allowing scientists to explore the deepest part of the sea and the furthest reaches of the solar system with the least weight penalty, the most flexibility and specialization of design, and without the need to provide for sustaining human life, or the risk of jeopardizing that life. Most NASA probes, including the historic Voyager I and II spacecraft and especially the Mars rovers, Spirit and Opportunity, feature remote operation, but new missions and new planetary environments will demand new capabilities from the robotic explorers of the future. NASA has an acute interest in the development of specialized ROVs, as new lessons learned on Earth can be applied to new environments and increasingly complex missions in the future of space exploration.

Near-Field Thermal Radiation for Solar Thermophotovoltaics and High Temperature Thermal Logic and Memory Applications

NASA Astrophysics Data System (ADS)

Elzouka, Mahmoud

This dissertation investigates Near-Field Thermal Radiation (NFTR) applied to MEMS-based concentrated solar thermophotovoltaics (STPV) energy conversion and thermal memory and logics. NFTR is the exchange of thermal radiation energy at nano/microscale; when separation between the hot and cold objects is less than dominant radiation wavelength (˜1 mum). NFTR is particularly of interest to the above applications due to its high rate of energy transfer, exceeding the blackbody limit by orders of magnitude, and its strong dependence on separation gap size, surface nano/microstructure and material properties. Concentrated STPV system converts solar radiation to electricity using heat as an intermediary through a thermally coupled absorber/emitter, which causes STPV to have one of the highest solar-to-electricity conversion efficiency limits (85.4%). Modeling of a near-field concentrated STPV microsystem is carried out to investigate the use of STPV based solid-state energy conversion as high power density MEMS power generator. Numerical results for In 0.18Ga0.82Sb PV cell illuminated with tungsten emitter showed significant enhancement in energy transfer, resulting in output power densities as high as 60 W/cm2; 30 times higher than the equivalent far-field power density. On thermal computing, this dissertation demonstrates near-field heat transfer enabled high temperature NanoThermoMechanical memory and logics. Unlike electronics, NanoThermoMechanical memory and logic devices use heat instead of electricity to record and process data; hence they can operate in harsh environments where electronics typically fail. NanoThermoMechanical devices achieve memory and thermal rectification functions through the coupling of near-field thermal radiation and thermal expansion in microstructures, resulting in nonlinear heat transfer between two temperature terminals. Numerical modeling of a conceptual NanoThermoMechanical is carried out; results include the dynamic response under write/read cycles for a practical silicon-based device. NanoThermoMechanical rectification is achieved experimentally--for the first time--with measurements at a high temperature of 600 K, demonstrating the feasibility of NanoThermoMechanical to operate in harsh environments. The proof-of-concept device has shown a maximum rectification of 10.9%. This dissertation proposes using meshed photonic crystal structures to enhance NFTR between surfaces. Numerical results show thermal rectification as high as 2500%. Incorporating these structures in thermal memory and rectification devices will significantly enhance their functionality and performance.

Heat-activated Plasmonic Chemical Sensors for Harsh Environments

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

Carpenter, Michael; Oh, Sang-Hyun

2015-12-01

A passive plasmonics based chemical sensing system to be used in harsh operating environments was investigated and developed within this program. The initial proposed technology was based on combining technologies developed at the SUNY Polytechnic Institute Colleges of Nanoscale Science and Engineering (CNSE) and at the University of Minnesota (UM). Specifically, a passive wireless technique developed at UM was to utilize a heat-activated plasmonic design to passively harvest the thermal energy from within a combustion emission stream and convert this into a narrowly focused light source. This plasmonic device was based on a bullseye design patterned into a gold filmmore » using focused ion beam methods (FIB). Critical to the design was the use of thermal stabilizing under and overlayers surrounding the gold film. These stabilizing layers were based on both atomic layer deposited films as well as metal laminate layers developed by United Technologies Aerospace Systems (UTAS). While the bullseye design was never able to be thermally stabilized for operating temperatures of 500oC or higher, an alternative energy harvesting design was developed by CNSE within this program. With this new development, plasmonic sensing results are presented where thermal energy is harvested using lithographically patterned Au nanorods, replacing the need for an external incident light source. Gas sensing results using the harvested thermal energy are in good agreement with sensing experiments, which used an external incident light source. Principal Component Analysis (PCA) was used to reduce the wavelength parameter space from 665 variables down to 4 variables with similar levels of demonstrated selectivity. The method was further improved by patterning rods which harvested energy in the near infrared, which led to a factor of 10 decrease in data acquisition times as well as demonstrated selectivity with a reduced wavelength data set. The combination of a plasmonic-based energy harvesting sensing paradigm with PCA analysis and wavelength down selection offers a novel path towards simplification and integration of plasmonic-based sensing methods using selected wavelengths rather than a full spectral analysis. Integration efforts were designed and modeled for thermal and mass transport considerations by UTAS which led to the 3D printing of scaled models that would serve as the housing for the alternative energy harvesting plasmonic chemical sensor design developed by CNSE.« less

Point-and-stare operation and high-speed image acquisition in real-time hyperspectral imaging

NASA Astrophysics Data System (ADS)

Driver, Richard D.; Bannon, David P.; Ciccone, Domenic; Hill, Sam L.

2010-04-01

The design and optical performance of a small-footprint, low-power, turnkey, Point-And-Stare hyperspectral analyzer, capable of fully automated field deployment in remote and harsh environments, is described. The unit is packaged for outdoor operation in an IP56 protected air-conditioned enclosure and includes a mechanically ruggedized fully reflective, aberration-corrected hyperspectral VNIR (400-1000 nm) spectrometer with a board-level detector optimized for point and stare operation, an on-board computer capable of full system data-acquisition and control, and a fully functioning internal hyperspectral calibration system for in-situ system spectral calibration and verification. Performance data on the unit under extremes of real-time survey operation and high spatial and high spectral resolution will be discussed. Hyperspectral acquisition including full parameter tracking is achieved by the addition of a fiber-optic based downwelling spectral channel for solar illumination tracking during hyperspectral acquisition and the use of other sensors for spatial and directional tracking to pinpoint view location. The system is mounted on a Pan-And-Tilt device, automatically controlled from the analyzer's on-board computer, making the HyperspecTM particularly adaptable for base security, border protection and remote deployments. A hyperspectral macro library has been developed to control hyperspectral image acquisition, system calibration and scene location control. The software allows the system to be operated in a fully automatic mode or under direct operator control through a GigE interface.

Global Positioning System Energetic Particle Data: The Next Space Weather Data Revolution

NASA Technical Reports Server (NTRS)

Knipp, Delores J.; Giles, Barbara L.

2016-01-01

The Global Positioning System (GPS) has revolutionized the process of getting from point A to point Band so much more. A large fraction of the worlds population relies on GPS (and its counterparts from other nations) for precision timing, location, and navigation. Most GPS users are unaware that the spacecraft providing the signals they rely on are operating in a very harsh space environment the radiation belts where energetic particles trapped in Earths magnetic field dash about at nearly the speed of light. These subatomic particles relentlessly pummel GPS satellites. So by design, every GPS satellite and its sensors are radiation hardened. Each spacecraft carries particle detectors that provide health and status data to system operators. Although these data reveal much about the state of the space radiation environment, heretofore they have been available only to system operators and supporting scientists. Research scientists have long sought a policy shift to allow more general access. With the release of the National Space Weather Strategy and Action Plan organized by the White House Office of Science Technology Policy (OSTP) a sample of these data have been made available to space weather researchers. Los Alamos National Laboratory (LANL) and the National Center for Environmental Information released a months worth of GPS energetic particle data from an interval of heightened space weather activity in early 2014 with the hope of stimulating integration of these data sets into the research arena. Even before the public data release GPS support scientists from LANL showed the extraordinary promise of these data.

The interaction of the near-field plasma with antennas used in magnetic fusion research

NASA Astrophysics Data System (ADS)

Caughman, John

2015-09-01

Plasma heating and current drive using antennas in the Ion Cyclotron Range of Frequencies (ICRF) are important elements for the success of magnetic fusion. The antennas must operate in a harsh environment, where local plasma densities can be >1018/m3, magnetic fields can range from 0.2-5 Tesla, and antenna operating voltages can be >40 kV. This environment creates operational issues due to the interaction of the near-field of the antenna with the local plasma. In addition to parasitic losses in this plasma region, voltage and current distributions on the antenna structure lead to the formation of high electric fields and RF plasma sheaths, which can lead to enhanced particle and energy fluxes on the antenna and on surfaces intersected by magnetic field lines connected to or passing near the antenna. These issues are being studied using a simple electrode structure and a single-strap antenna on the Prototype Materials Plasma EXperiment (Proto-MPEX) at ORNL, which is a linear plasma device that uses an electron Bernstein wave heated helicon plasma source to create a high-density plasma suitable for use in a plasma-material interaction test stand. Several diagnostics are being used to characterize the near-field interactions, including double-Langmuir probes, a retarding field energy analyzer, and optical emission spectroscopy. The RF electric field is being studied utilizing Dynamic Stark Effect spectroscopy and Doppler-Free Saturation Spectroscopy. Recent experimental results and future plans will be presented. ORNL is managed by UT-Battelle, LLC, for the U.S. DOE under Contract DE-AC-05-00OR22725.

Zein-alginate based oral drug delivery systems: Protection and release of therapeutic proteins.

PubMed

Lee, Sungmun; Kim, Yeu-Chun; Park, Ji-Ho

2016-12-30

Reactive oxygen species (ROS) play an important role in the development of inflammatory bowel diseases. Superoxide dismutase (SOD) has a great therapeutic potential by scavenging superoxide that is one of ROS; however, in vivo application is limited especially when it is orally administered. SOD is easily degraded in vivo by the harsh conditions of gastrointestinal tract. Here, we design a zein-alginate based oral drug delivery system that protects SOD from the harsh conditions of gastrointestinal tract and releases it in the environment of the small intestine. SOD is encapsulated in zein-alginate nanoparticles (ZAN) via a phase separation method. We demonstrate that ZAN protect SOD from the harsh conditions of the stomach or small intestine condition. ZAN (200:40) at the weight ratio of 200mg zein to 40mg of alginate releases SOD in a pH dependent manner, and it releases 90.8±1.2% of encapsulated SOD at pH 7.4 in 2h, while only 11.4±0.4% of SOD was released at pH 1.3. The encapsulation efficiency of SOD in ZAN (200:40) was 62.1±2.0%. SOD in ZAN (200:40) reduced the intracellular ROS level and it saved 88.9±7.5% of Caco-2 cells from the toxic superoxide in 4 hours. Based on the results, zein-alginate based oral drug delivery systems will have numerous applications to drugs that are easily degradable in the harsh conditions of gastrointestinal tract. Copyright © 2016 Elsevier B.V. All rights reserved.

Wireless and chip-less passive radiation sensors for high dose monitoring

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

Debourg, E.; Aubert, H.; Pons, P.

The safety of nuclear infrastructures may involve the monitoring of many parameters in harsh environments (high radiation level, high temperature, high pressure,..). If technological solutions exist for transducers part in such environments, the electronic part used in reader is not appropriate and still a challenging task. Well-known solutions to remove the electronic part from the harsh environment consist of connecting the transducer and the reader by long electrical wires or performing ex situ remote sensing. However wires may practically be difficult to implement while ex situ measurements are not compatible with on line monitoring. Wireless and passive sensors working inmore » harsh environments could be an appropriate solution for the remote sensing of critical parameters. Passive sensors without electronics in the sensing unit are available (e.g., SAW sensors) but they suffer from short reading range (typically lower than 10 meters). In order to overcome this range limitation a new class of electromagnetic transducers was developed in the mid-2000's. The operating principle is based on the modification of the properties of high-frequency (>> 1 GHz) passive electromagnetic devices by the quantity to be measured. Based on this principle a wide range of sensing properties can be addressed and a large number of materials can be chosen. Moreover the use of high frequency allows reducing the size of the sensor elements (antenna, transducer) and enhancing the immunity to multi-path. Several principles of RF transducers have been already validated by LAAS-CNRS (e;g; pressure, temperature, stress) as well as radar-based solution for the wireless long-range sensors interrogation. The sensor dosimeter exploit here the known property of Hydrogen-Pressure Dosimeters (HPD) for which the polymer material dehydrogenates under nuclear irradiation. The transducer principle is described. The irradiation will generate the out-gazing (hydrogen) of the polymer inside a micro-chamber. The resulting overpressure leads to the deflection of a silicon membrane which modifies the resonant frequency of the RF resonator. Tests structures have been designed in order to quantify the HDPE out-gazing inside a micro-cavity by measuring the deflection of a boss silicon membrane with a mechanical profiler. A specific set up using interferometry method has been also developed to evaluate the pressure generated inside the micro-cavity. The procedure consists in applying a pressure that pushes the membrane to recover a flat membrane. This condition is monitored thanks to the extinction of the Newton rings. Irradiations have been performed up to 30 kGy using 6 MeV focused e-beam providing by electron accelerator. Membrane deflection and generated pressure around 0.2 μm/mg{sub HDPE}/kGy and 70 mbar/mg{sub HDPE}/kGy has been obtained for a 70 μm thick membrane. In order to characterize the hermetic sealing of the micro-chamber under hydrogen over-pressure, membrane deflection after irradiation has been recorded during 50 days. The variations of membrane deflection are randomly distributed and generally lower than ±5%, showing a good hermeticity during this period. (authors)« less

Enough Bad News! Remote Social Health & Aboriginal Action in a Harsh Environment--Coober Pedy in South Australia's "Outback."

ERIC Educational Resources Information Center

Brice, G.; And Others

This paper focuses on the complexities of health care in Coober Pedy (South Australia) and the nearby Umoona Aboriginal community, and highlights the vital role of Aboriginal health workers in the implementation of primary health care principles. The Aboriginal population in this "outback" area is characterized by considerable economic…

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

Treesearch

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

2013-01-01

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

Fiber optic sensor and method for making

DOEpatents

Vartuli, James Scott; Bousman, Kenneth Sherwood; Deng, Kung-Li; McEvoy, Kevin Paul; Xia, Hua

2010-05-18

A fiber optic sensor including a fiber having a modified surface integral with the fiber wherein the modified surface includes an open pore network with optical agents dispersed within the open pores of the open pore network. Methods for preparing the fiber optic sensor are also provided. The fiber optic sensors can withstand high temperatures and harsh environments.

Polyphosphazene semipermeable membranes

DOEpatents

Allen, Charles A.; McCaffrey, Robert R.; Cummings, Daniel G.; Grey, Alan E.; Jessup, Janine S.; McAtee, Richard E.

1988-01-01

A semipermeable, inorganic membrane is disclosed; the membrane is prepared from a phosphazene polymer and, by the selective substitution of the constituent groups bound to the phosphorous in the polymer structure, the selective passage of fluid from a feedstream can be controlled. Resistance to high temperatures and harsh chemical environments is observed in the use of the phosphazene polymers as semipermeable membranes.

Corrosion of Wires on Wooden Wire-Bound Packaging Crates

Treesearch

Samuel L. Zelinka; Stan Lebow

2015-01-01

Wire-bound packaging crates are used by the US Army to transport materials. Because these crates may be exposed to harsh environments, they are dip-treated with a wood preservative (biocide treatment). For many years, zinc-naphthenate was the most commonly used preservative for these packaging crates and few corrosion problems with the wires were observed. Recently,...

Wireless Fluid-Level Sensors for Harsh Environments

NASA Technical Reports Server (NTRS)

Woodward, Stanley E.

2009-01-01

Magnetic-field-response sensors have been developed for use in measuring levels of fluids under extreme conditions. The sensors work without wire connections or direct physical contact with power sources, microprocessors, data-acquisition equipment, or electrical circuitry. For fuel-level sensors, the absence of wire connections offers an important safety advantage in elimination of potential ignition sources.

Single Event Testing on Complex Devices: Test Like You Fly versus Test-Specific Design Structures

NASA Technical Reports Server (NTRS)

Berg, Melanie; LaBel, Kenneth A.

2014-01-01

We present a framework for evaluating complex digital systems targeted for harsh radiation environments such as space. Focus is limited to analyzing the single event upset (SEU) susceptibility of designs implemented inside Field Programmable Gate Array (FPGA) devices. Tradeoffs are provided between application-specific versus test-specific test structures.

Overexpression of Arabidopsis thaliana PTEN caused accumulation of autophagic bodies in pollen tubes by disrupting phosphatidylinositol 3-phosphate dynamics

USDA-ARS?s Scientific Manuscript database

Autophagy is a pathway in eukaryotes by which nutrient remobilization occurs through bulk protein and organelle turnover. Autophagy not only aides cells in coping with harsh environments but also plays a key role in many physiological processes that include pollen germination and tube growth. Most a...

Creep Performance of Oxide Ceramic Fiber Materials at Elevated Temperature in Air and in Steam

DTIC Science & Technology

2011-03-24

engineered materials are finding more and more applications in space, aeronautics, energy, automotive, and other industries . In particular, engineered...performance in harsh environments are prime candidates for such applications . Oxide ceramic materials have been used as constituents in CMCs...183  xviii List of Tables Page Table 1.  CMC Applications [2

Power Converters Secure Electronics in Harsh Environments

NASA Technical Reports Server (NTRS)

2013-01-01

In order to harden power converters for the rigors of space, NASA awarded multiple SBIR contracts to Blacksburg, Virginia-based VPT Inc. The resulting hybrid DC-DC converters have proven valuable in aerospace applications, and as a result the company has generated millions in revenue from the product line and created four high-tech jobs to handle production.

Promoting Safe Schools and Academic Success: Moving Your School from Punitive Discipline to Effective Discipline

ERIC Educational Resources Information Center

Olley, Rivka I.; Cohn, Andrea; Cowan, Katherine C.

2010-01-01

Effective discipline is essential to creating safe, supportive learning environments for all students, which is critical to academic achievement. Since the passage of zero tolerance policies in the early 1990s, many school districts have relied on punitive discipline focused on harsh strategies such as using suspension and expulsion as primary…

Forming Planets in the Hostile Carina Nebula

NASA Astrophysics Data System (ADS)

Kohler, Susanna

2016-07-01

Can protoplanetary disks form and be maintained around low-mass stars in the harsh environment of a highly active, star-forming nebula? A recent study examines the Carina nebula to answer this question.Crowded ClustersStars are often born in clusters that contain both massive and low-mass stars. The most massive stars in these clusters emit far-ultraviolet and extreme-ultraviolet light that irradiates the region around them, turning the surrounding area into a hostile environment for potential planet formation.Planet formation from protoplanetary disks typically requires timescales of at least 12 million years. Could the harsh radiation from massive stars destroy the protoplanetary disks around low-mass stars by photoevaporation before planets even have a chance to form?Artists impression of a protoplanetary disk. Such disks can be photoevaporated by harsh ultraviolet light from nearby massive stars, causing the disk to be destroyed before planets have a chance to form within them. [ESO/L. Calada]Turning ALMA Toward CarinaA perfect case study for exploring hostile environments is the Carina nebula, located about 7500 lightyears away and home to nearly 100 O-type stars as well as tens of thousands of lower-mass young stars. The Carina population is ~14 Myr old: old enough to form planets within protoplanetary disks, but also old enough that photoevaporation could already have wreaked havoc on those disks.Due to the dense stellar populations in Carinas clusters, this is a difficult region to explore, but the Atacama Large Millimeter-submillimeter Array (ALMA) is up to the task. In a recent study, a team of scientists led by Adal Mesa-Delgado (Pontifical Catholic University of Chile) made use of ALMAs high spatial resolution to image four regions spaced throughout Carina, searching for protoplanetary disks.Detections and Non-DetectionsTwo evaporating gas globules in the Carina nebula, 104-593 and 105-600, that each contain a protoplanetary disk. The top panels are Hubble images of the globules; the bottom panels are ALMA images of the disks detected within them. [Mesa-Delgado et al. 2016]In searching regions outside of the densest, most luminous clusters, the team succeeded in detecting two protoplanetary disks. This region in Carina now marks the most distant massive cluster in which disks have ever been imaged! The discovered disks have radii of roughly 60 AU and masses of 30 and 50 Jupiter masses and given their ages, its entirely plausible that planets are actively forming in these disks.Equally important: Mesa-Delgado and collaborators failed to detect any indication of disks in the core of Trumpler 14, a cluster in Carina that is home to some of the most massive and luminous stars in the Galaxy. This non-detection suggests that the particularly harsh environment of Trumpler 14 is too brutal for disks within it to survive.These observations provide new clues as to where we should be looking to study planet formation: less dense regions in star-forming nebulae seem to be locations that can support giant-planet-forming disks, whereas the harsh radiation fields of especially dense subclusters seem to cause the rapid destruction of such disks.CitationA. Mesa-Delgado et al 2016 ApJ 825 L16. doi:10.3847/2041-8205/825/1/L16

Highly sensitive avoidance plays a key role in sensory adaptation to deep-sea hydrothermal vent environments.

PubMed

Ogino, Tetsuya; Maegawa, Shingo; Shigeno, Shuichi; Fujikura, Katsunori; Toyohara, Haruhiko

2018-01-01

The environments around deep-sea hydrothermal vents are very harsh conditions for organisms due to the possibility of exposure to highly toxic compounds and extremely hot venting there. Despite such extreme environments, some indigenous species have thrived there. Alvinellid worms (Annelida) are among the organisms best adapted to high-temperature and oxidatively stressful venting regions. Although intensive studies of the adaptation of these worms to the environments of hydrothermal vents have been made, little is known about the worms' sensory adaptation to the severe chemical conditions there. To examine the sensitivity of the vent-endemic worm Paralvinella hessleri to low pH and oxidative stress, we determined the concentration of acetic acid and hydrogen peroxide that induced avoidance behavior of this worm, and compared these concentrations to those obtained for related species inhabiting intertidal zones, Thelepus sp. The concentrations of the chemicals that induced avoidance behavior of P. hessleri were 10-100 times lower than those for Thelepus sp. To identify the receptors for these chemicals, chemical avoidance tests were performed with the addition of ruthenium red, a blocker of transient receptor potential (TRP) channels. This treatment suppressed the chemical avoidance behavior of P. hessleri, which suggests that TRP channels are involved in the chemical avoidance behavior of this species. Our results revealed for the first time hypersensitive detection systems for acid and for oxidative stress in the vent-endemic worm P. hessleri, possibly mediated by TRP channels, suggesting that such sensory systems may have facilitated the adaptation of this organism to harsh vent environments.

A Green Robotic Observatory for Astronomy Education

NASA Astrophysics Data System (ADS)

Reddy, Vishnu; Archer, K.

2008-09-01

With the development of robotic telescopes and stable remote observing software, it is currently possible for a small institution to have an affordable astronomical facility for astronomy education. However, a faculty member has to deal with the light pollution (observatory location on campus), its nightly operations and regular maintenance apart from his day time teaching and research responsibilities. While building an observatory at a remote location is a solution, the cost of constructing and operating such a facility, not to mention the environmental impact, are beyond the reach of most institutions. In an effort to resolve these issues we have developed a robotic remote observatory that can be operated via the internet from anywhere in the world, has a zero operating carbon footprint and minimum impact on the local environment. The prototype observatory is a clam-shell design that houses an 8-inch telescope with a SBIG ST-10 CCD detector. The brain of the observatory is a low draw 12-volt harsh duty computer that runs the dome, telescope, CCD camera, focuser, and weather monitoring. All equipment runs of a 12-volt AGM-style battery that has low lead content and hence more environmental-friendly to dispose. The total power of 12-14 amp/hrs is generated from a set of solar panels that are large enough to maintain a full battery charge for several cloudy days. This completely eliminates the need for a local power grid for operations. Internet access is accomplished via a high-speed cell phone broadband connection or satellite link eliminating the need for a phone network. An independent observatory monitoring system interfaces with the observatory computer during operation. The observatory converts to a trailer for transportation to the site and is converted to a semi-permanent building without wheels and towing equipment. This ensures minimal disturbance to local environment.

Improving OBS operations in ultra-deep ocean during the Southern Mariana Trench expeditions

NASA Astrophysics Data System (ADS)

Zeng, X.; Lin, J.; Xu, M.; Zhou, Z.

2017-12-01

The Mariana Trench Research Initiative, led by the South China Sea Institute of Oceanology of the Chinese Academy of Sciences and through international collaboration, focuses on investigating the deep and shallow lithospheric structure, earthquake characteristics, extreme geological environments, and the controlling geodynamic mechanisms for the formation of Earth's deepest basins in the southern Mariana Trench. Two multidisciplinary research expeditions were executed during December 2016 and June 2017, respectively, on board R/V Shiyan 3. A main task of the Mariana Initiative is to conduct the Southern Mariana OBS Experiment (SMOE), the first OBS seismic experiment across the Challenger Deep. The SMOE expeditions include both active and passive source seismic experiments and employed a large number of broadband OBS instruments. Due to the deep water, rough weather, strong winds, and other unfavorable factors, it was challenging to deploy/recover the OBSs. During the two expeditions we developed and experimented with a number of ways to improve the success rate of OBS operations in the harsh ultra-deep ocean environment of the Southern Mariana Trench. All newly acquired OBSs underwent a series of uniquely designed deep-ocean tests to improve the instrument performance and maximize reliability during their deployment under the ultra-high pressure conditions. The OBS deployment and recovery followed a unified standard operation procedure and aided by an instrumental checklist, which were specifically designed and strictly enforced for operation during the expeditions. Furthermore, an advanced ship-based radio positioning system was developed to rapidly and accurately locate the OBS instruments when they reached the sea surface; the system proved its effectiveness even under extreme weather conditions. Through the development and application of the novel methods for operation in deep oceans, we overcame the rough sea and other unfavorable factors during the first two expeditions to the southern Mariana Trench and achieved a highly successful OBS operation program.

A Magnetoresistive Tactile Sensor for Harsh Environment Applications

PubMed Central

Alfadhel, Ahmed; Khan, Mohammed Asadullah; Cardoso, Susana; Leitao, Diana; Kosel, Jürgen

2016-01-01

A magnetoresistive tactile sensor is reported, which is capable of working in high temperatures up to 140 °C. Hair-like bioinspired structures, known as cilia, made out of permanent magnetic nanocomposite material on top of spin-valve giant magnetoresistive (GMR) sensors are used for tactile sensing at high temperatures. The magnetic nanocomposite, consisting of iron nanowires incorporated into the polymer polydimethylsiloxane (PDMS), is very flexible, biocompatible, has high remanence, and is also resilient to antagonistic sensing ambient. When the cilia come in contact with a surface, they deflect in compliance with the surface topology. This yields a change of the GMR sensor signal, enabling the detection of extremely fine features. The spin-valve is covered with a passivation layer, which enables adequate performance in spite of harsh environmental conditions, as demonstrated in this paper for high temperature. PMID:27164113

A test of the adaptive specialization hypothesis: population differences in caching, memory, and the hippocampus in black-capped chickadees (Poecile atricapilla).

PubMed

Pravosudov, Vladimir V; Clayton, Nicola S

2002-08-01

To test the hypothesis that accurate cache recovery is more critical for birds that live in harsh conditions where the food supply is limited and unpredictable, the authors compared food caching, memory, and the hippocampus of black-capped chickadees (Poecile atricapilla) from Alaska and Colorado. Under identical laboratory conditions, Alaska chickadees (a) cached significantly more food; (b) were more efficient at cache recovery: (c) performed more accurately on one-trial associative learning tasks in which birds had to rely on spatial memory, but did not differ when tested on a nonspatial version of this task; and (d) had significantly larger hippocampal volumes containing more neurons compared with Colorado chickadees. The results support the hypothesis that these population differences may reflect adaptations to a harsh environment.

Characterization of Industrial Coolant Fluids and Continuous Ageing Monitoring by Wireless Node-Enabled Fiber Optic Sensors.

PubMed

Sachat, Alexandros El; Meristoudi, Anastasia; Markos, Christos; Sakellariou, Andreas; Papadopoulos, Aggelos; Katsikas, Serafim; Riziotis, Christos

2017-03-11

Environmentally robust chemical sensors for monitoring industrial processes or infrastructures are lately becoming important devices in industry. Low complexity and wireless enabled characteristics can offer the required flexibility for sensor deployment in adaptable sensing networks for continuous monitoring and management of industrial assets. Here are presented the design, development and operation of a class of low cost photonic sensors for monitoring the ageing process and the operational characteristics of coolant fluids used in an industrial heavy machinery infrastructure. The chemical, physical and spectroscopic characteristics of specific industrial-grade coolant fluids were analyzed along their entire life cycle range, and proper parameters for their efficient monitoring were identified. Based on multimode polymer or silica optical fibers, wide range (3-11) pH sensors were developed by employing sol-gel derived pH sensitive coatings. The performances of the developed sensors were characterized and compared, towards their coolants' ageing monitoring capability, proving their efficiency in such a demanding application scenario and harsh industrial environment. The operating characteristics of this type of sensors allowed their integration in an autonomous wireless sensing node, thus enabling the future use of the demonstrated platform in wireless sensor networks for a variety of industrial and environmental monitoring applications.

Turning a blind eye: the mobilization of radiology services in resource-poor regions

PubMed Central

2010-01-01

While primary care, obstetrical, and surgical services have started to expand in the world's poorest regions, there is only sparse literature on the essential support systems that are required to make these operations function. Diagnostic imaging is critical to effective rural healthcare delivery, yet it has been severely neglected by the academic, public, and private sectors. Currently, a large portion of the world's population lacks access to any form of diagnostic imaging. In this paper we argue that two primary imaging modalities--diagnostic ultrasound and X-Ray--are ideal for rural healthcare services and should be scaled-up in a rapid and standardized manner. Such machines, if designed for resource-poor settings, should a) be robust in harsh environmental conditions, b) function reliably in environments with unstable electricity, c) minimize radiation dangers to staff and patients, d) be operable by non-specialist providers, and e) produce high-quality images required for accurate diagnosis. Few manufacturers are producing ultrasound and X-Ray machines that meet the specifications needed for rural healthcare delivery in resource-poor regions. A coordinated effort is required to create demand sufficient for manufacturers to produce the desired machines and to ensure that the programs operating them are safe, effective, and financially feasible. PMID:20946643

Turning a blind eye: the mobilization of radiology services in resource-poor regions.

PubMed

Maru, Duncan Smith-Rohrberg; Schwarz, Ryan; Jason, Andrews; Basu, Sanjay; Sharma, Aditya; Moore, Christopher

2010-10-14

While primary care, obstetrical, and surgical services have started to expand in the world's poorest regions, there is only sparse literature on the essential support systems that are required to make these operations function. Diagnostic imaging is critical to effective rural healthcare delivery, yet it has been severely neglected by the academic, public, and private sectors. Currently, a large portion of the world's population lacks access to any form of diagnostic imaging. In this paper we argue that two primary imaging modalities--diagnostic ultrasound and X-Ray--are ideal for rural healthcare services and should be scaled-up in a rapid and standardized manner. Such machines, if designed for resource-poor settings, should a) be robust in harsh environmental conditions, b) function reliably in environments with unstable electricity, c) minimize radiation dangers to staff and patients, d) be operable by non-specialist providers, and e) produce high-quality images required for accurate diagnosis. Few manufacturers are producing ultrasound and X-Ray machines that meet the specifications needed for rural healthcare delivery in resource-poor regions. A coordinated effort is required to create demand sufficient for manufacturers to produce the desired machines and to ensure that the programs operating them are safe, effective, and financially feasible.

Extended Life PZT Stack Test Fixture

NASA Technical Reports Server (NTRS)

Badescu, Mircea; Sherrit, S.; Bao, X.; Aldrich, J.; Bar-Cohen, Y.; Jones, C.

2009-01-01

Piezoelectric stacks are being sought to be used as actuators for precision positioning and deployment of mechanisms in future planetary missions. Beside the requirement for very high operation reliability, these actuators are required for operation at space environments that are considered harsh compared to normal terrestrial conditions.These environmental conditions include low and high temperatures and vacuum or high pressure. Additionally, the stacks are subjected to high stress and in some applications need to operate with a very long lifetime durability.Many of these requirements are beyond the current industry design margins for nominal terrestrial applications. In order to investigate some of the properties that will indicate the durability of such actuators and their limitations we have developed a new type of test fixture that can be easily integrated in various test chambers for simulating environmental conditions, can provide access for multiple measurements while being exposed to adjustable stress levels. We designed and built two test fixtures and these fixtures were made to be adjustable for testing stacks with different dimensions and can be easily used in small or large numbers. The properties that were measured using these fixtures include impedance, capacitance, dielectric loss factor, leakage current, displacement, breakdown voltage, and lifetime performance. The fixtures characteristics and the test capabilities are presented in this paper.

Neural-network-directed alignment of optical systems using the laser-beam spatial filter as an example

NASA Technical Reports Server (NTRS)

Decker, Arthur J.; Krasowski, Michael J.; Weiland, Kenneth E.

1993-01-01

This report describes an effort at NASA Lewis Research Center to use artificial neural networks to automate the alignment and control of optical measurement systems. Specifically, it addresses the use of commercially available neural network software and hardware to direct alignments of the common laser-beam-smoothing spatial filter. The report presents a general approach for designing alignment records and combining these into training sets to teach optical alignment functions to neural networks and discusses the use of these training sets to train several types of neural networks. Neural network configurations used include the adaptive resonance network, the back-propagation-trained network, and the counter-propagation network. This work shows that neural networks can be used to produce robust sequencers. These sequencers can learn by example to execute the step-by-step procedures of optical alignment and also can learn adaptively to correct for environmentally induced misalignment. The long-range objective is to use neural networks to automate the alignment and operation of optical measurement systems in remote, harsh, or dangerous aerospace environments. This work also shows that when neural networks are trained by a human operator, training sets should be recorded, training should be executed, and testing should be done in a manner that does not depend on intellectual judgments of the human operator.

Characterization of Industrial Coolant Fluids and Continuous Ageing Monitoring by Wireless Node—Enabled Fiber Optic Sensors

PubMed Central

El Sachat, Alexandros; Meristoudi, Anastasia; Markos, Christos; Sakellariou, Andreas; Papadopoulos, Aggelos; Katsikas, Serafim; Riziotis, Christos

2017-01-01

Environmentally robust chemical sensors for monitoring industrial processes or infrastructures are lately becoming important devices in industry. Low complexity and wireless enabled characteristics can offer the required flexibility for sensor deployment in adaptable sensing networks for continuous monitoring and management of industrial assets. Here are presented the design, development and operation of a class of low cost photonic sensors for monitoring the ageing process and the operational characteristics of coolant fluids used in an industrial heavy machinery infrastructure. The chemical, physical and spectroscopic characteristics of specific industrial-grade coolant fluids were analyzed along their entire life cycle range, and proper parameters for their efficient monitoring were identified. Based on multimode polymer or silica optical fibers, wide range (3–11) pH sensors were developed by employing sol-gel derived pH sensitive coatings. The performances of the developed sensors were characterized and compared, towards their coolants’ ageing monitoring capability, proving their efficiency in such a demanding application scenario and harsh industrial environment. The operating characteristics of this type of sensors allowed their integration in an autonomous wireless sensing node, thus enabling the future use of the demonstrated platform in wireless sensor networks for a variety of industrial and environmental monitoring applications. PMID:28287488

Electric propulsion using the permanent magnet synchronous motor without rotor position transducers

NASA Astrophysics Data System (ADS)

Batzel, Todd Douglas

The permanent magnet synchronous motor (PMSM) is increasingly playing an important role in electric propulsion systems due to its many advantages over competing technologies. For successful operation of the PMSM, rotor position and speed information is required. A resolver or encoder attached to the shaft of the machine usually provides this information. Many applications, however, cannot tolerate the use of the position sensor because of space and weight limitations, reliability concerns, or packaging issues. Thus, there has been an intense interest in the development of a so-called position sensorless drive, where the PMSM stator itself is used as the rotor position sensor. In this work, a sensorless electric drive is developed for various undersea propulsion applications, where the rotor position sensor is often undesirable due to the harsh operating environment as well as space and weight limitations. In this work, an observer is developed which enables sensorless operation of the PMSM over a wide speed range. In addition, a method is presented for estimating the standstill rotor angle, an operating condition at which the rotor position observers are typically ill conditioned. In this work two design methodologies are applied to the sensorless electric drive application, including a model-based and a neural network-based approach. Implementation issues for the sensorless electric drive are discussed, and experimental results are presented in order to demonstrate the effectiveness of the proposed techniques to the sensorless PMSM.

Electronic thermal sensor and Data Collection Platform technology: Part 5 in Thermal surveillance of active volcanoes using the Landsat-1 Data Collection System

USGS Publications Warehouse

Preble, Duane M.; Friedman, Jules D.; Frank, David

1976-01-01

Five Data Collection Platforms (DCP) were integrated electronically with thermall sensing systems, emplaced and operated in an analog mode at selected thermally significant volcanic and geothermal sites. The DCP's transmitted 3260 messages comprising 26,080 ambient, surface, and near-surface temperature records at an accuracy of ±1.15 °C for 1121 instrument days between November 14, 1972 and April 17, 1974. In harsh, windy, high-altitude volcanic environments the DCP functioned best with a small dipole antenna. Sixteen kg of alkaline batteries provided a viable power supply for the DCP systems, operated at a low-duty cycle, for 5 to 8 months. A proposed solar power supply system would lengthen the period of unattended operation of the system considerably. Special methods of data handling such as data storage via a proposed memory system would increase the significance of the twice-daily data reception enabling the DCP's to record full diurnal-temperature cycles at volcanic or geothermal sites. Refinements in the temperature-monitoring system designed and operated in experiment SR 251 included a backup system consisting of a multipoint temperature scanner, a servo mechanism and an analog-to-digital recorder. Improvements were made in temperature-probe design and in construction of corrosion-resistant seals by use of a hydrofluoric-acid-etching technique.

Remotely Operating a Fourier Transform Spectrometer for Atmospheric Remote Sensing

NASA Technical Reports Server (NTRS)

Blavier, J.-F.; Toon, G. C.; Sen, B.

2000-01-01

This paper describes how the MkIV instrument was adapted for remote operation from the Barcroft site, where the harsh winter conditions make access difficult. Some of the main technical challenges will be discussed including, (i) operation from solar panels and batteries, (ii) cooling the detectors with LN2, (iii) instrument control and monitoring over a cellular phone, and (iv) data storage, processing and analysis. Finally, MkIV spectra measured from Barcroft and compared with those measured from JPL to highlight the advantages of the higher altitude site.

Disrupting intergenerational continuity in harsh and abusive parenting: the importance of a nurturing relationship with a romantic partner.

PubMed

Conger, Rand D; Schofield, Thomas J; Neppl, Tricia K; Merrick, Melissa T

2013-10-01

Harsh, abusive, and rejecting behavior by parents toward their children is associated with increased risk for many developmental problems for youth. Earlier research also shows that children raised by harsh parents are more likely to treat their own children harshly. The present study evaluated nurturing and supportive behaviors of spouses or cohabiting romantic partners hypothesized to strengthen co-parent relationships and help break this intergenerational cycle of harsh parenting. Data come from the Family Transitions Project, a 22-year, 3-generation study of a cohort of over 500 early adolescents (G2) grown to adulthood. During adolescence, observers rated G1 (parent of G2) harsh parenting to G2. Several years later, observers rated G2 harsh parenting toward their oldest child (G3). In addition, G2's romantic partner (spouse or cohabiting partner) was rated by observers on a range of behaviors expected to affect G2 harsh parenting. Romantic partner warmth and positive communication with G2 were associated with less G2 harsh parenting toward G3 (a compensatory or main effect) and when these partner behaviors were high, there was no evidence of intergenerational continuity from G1 to G2 harsh parenting (a moderating or protective effect). G1 harsh parenting slightly decreased the likelihood that G2 would select a supportive spouse or romantic partner (evidence of cumulative continuity). Romantic partner warmth and positive communication appear to disrupt continuity in harsh and abusive parenting. As appropriate, preventive interventions designed to reduce risk for child maltreatment should include a focus on spousal or partner behaviors in their educational or treatment programs. Copyright © 2013 Society for Adolescent Health and Medicine. Published by Elsevier Inc. All rights reserved.

Development of a cryogenic all-silicon telescope (CAIT)

NASA Astrophysics Data System (ADS)

McCarter, Douglas R.; McCarter, Eloise; Paquin, Roger

2012-09-01

Mankind loves space and is drawn to explore its vastness. Existing space telescopes routinely encounter data losses and delayed data collections during the constantly changing temperature and load disruptions of space missions. The harsh environment of space thermal cycles and spacecraft motion loads create unwanted activity such as spacecraft slew, acquisition slew, and temperature induced blur. In order to compensate for the low performance of the materials currently used for telescope optics, engineers and designers are using costly on-board coolers, mechanical actuators, and deformed mirrors, for example, with limited success. However, Zero-defect Single Crystal Silicon (SCSi) can perform in space environments without coolers, actuators, and other such devices because SCSi is not ductile and is homogeneous and therefore is not subject to creep, and will not jitter, or blur during operations. To take advantage of the unique advantages of Zero-defect SCSi, we are developing and fabricating a Cryostable All-Silicon Imaging Telescope (CAIT). In this paper, we will discuss the basis for selecting SCSi for our space telescope design, the status of the CAIT design and fabrication progress, and compare SCSi thermal and strength properties with other typical space optical materials.

Performance Analysis of the Ironless Inductive Position Sensor in the Large Hadron Collider Collimators Environment

PubMed Central

Danisi, Alessandro; Masi, Alessandro; Losito, Roberto

2015-01-01

The Ironless Inductive Position Sensor (I2PS) has been introduced as a valid alternative to Linear Variable Differential Transformers (LVDTs) when external magnetic fields are present. Potential applications of this linear position sensor can be found in critical systems such as nuclear plants, tokamaks, satellites and particle accelerators. This paper analyzes the performance of the I2PS in the harsh environment of the collimators of the Large Hadron Collider (LHC), where position uncertainties of less than 20 µm are demanded in the presence of nuclear radiation and external magnetic fields. The I2PS has been targeted for installation for LHC Run 2, in order to solve the magnetic interference problem which standard LVDTs are experiencing. The paper describes in detail the chain of systems which belong to the new I2PS measurement task, their impact on the sensor performance and their possible further optimization. The I2PS performance is analyzed evaluating the position uncertainty (on 30 s), the magnetic immunity and the long-term stability (on 7 days). These three indicators are assessed from data acquired during the LHC operation in 2015 and compared with those of LVDTs. PMID:26569259

ALDO: A radiation-tolerant, low-noise, adjustable low drop-out linear regulator in 0.35 μm CMOS technology

NASA Astrophysics Data System (ADS)

Carniti, P.; Cassina, L.; Gotti, C.; Maino, M.; Pessina, G.

2016-07-01

In this work we present ALDO, an adjustable low drop-out linear regulator designed in AMS 0.35 μm CMOS technology. It is specifically tailored for use in the upgraded LHCb RICH detector in order to improve the power supply noise for the front end readout chip (CLARO). ALDO is designed with radiation-tolerant solutions such as an all-MOS band-gap voltage reference and layout techniques aiming to make it able to operate in harsh environments like High Energy Physics accelerators. It is capable of driving up to 200 mA while keeping an adequate power supply filtering capability in a very wide frequency range from 10 Hz up to 100 MHz. This property allows us to suppress the noise and high frequency spikes that could be generated by a DC/DC regulator, for example. ALDO also shows a very low noise of 11.6 μV RMS in the same frequency range. Its output is protected with over-current and short detection circuits for a safe integration in tightly packed environments. Design solutions and measurements of the first prototype are presented.

An unusual case of an immersion hand presentation in a military signaller operating in the jungle in Belize.

PubMed

Forbes, Kirstie E; Foster, P

2017-12-01

Belize, hosting one of the British Army's overseas training areas, provides access to challenging terrain and austere environments, which allows the delivery of training to soldiers on survival and combat within the jungle environment. A 26-year-old infanteer on exercise in Belize presented with progressive bilateral dry, painful, oedematous hands, secondary to the harsh environmental conditions of the jungle and inadequate drying of his hands resulting in his inability to perform his combat duties. The symptoms completely resolved with drying, emollient application and analgesia. While there are no reported cases of immersion hand, comparisons can be made with the well-reported warm weather immersion foot. This case highlights the importance of force preparation and soldier education for units deploying to the jungle. Simple preventive measures, including adequate 'wet-dry' drills and use of emollients can reduce the prevalence of immersion hand, a preventable condition, which can have a significant impact on the overall combat effectiveness of the unit. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

Field experience and performance evaluation of a medium-concentration CPV system

NASA Astrophysics Data System (ADS)

Norton, Matthew; Bentley, Roger; Georghiou, George E.; Chonavel, Sylvain; De Mutiis, Alfredo

2012-10-01

With the aim of gaining experience and performance data from location with a harsh summer climate, a 70 X concentrating photovoltaic (CPV) system was installed in Janurary 2009 in Nicosia, Cyprus. The performance of this system has been monitored using regular current-voltage characterisations for three years. Over this period, the output of the system has remained fairly constant. Measured performance ratios varied from 0.79 to 0.86 in the winter, but fell to 0.64 over the year when left uncleaned. Operating cell temperatures were modeled and found to be similar to those of flat plate modules. The most significant causes of energy loss have been identified as originating from tracking issues and soiling. Losses due to soiling could account for a drop in output of 0.2% per day. When cleaned and properly oriented, the normalized output of the system has remained constant, suggesting that this particular design is tolerant to the physical strain of long-term outdoor exposure in harsh summer conditions. Regular cleaning and reliable tracker operation are shown to be essential for maximizing energy yield.

Parental harsh discipline in mainland China: prevalence, frequency, and coexistence.

PubMed

Wang, Meifang; Liu, Li

2014-06-01

The study examined the prevalence, frequency, and coexistence of psychological aggression (PA), corporal punishment (CP), and severe physical abuse (SPA) in mainland China. Using a sample of 2,518 father-mother dyads of 3-15-year-old children, the findings revealed that parental harsh discipline was prevalent in mainland China. The rates of harsh discipline in the current study fell in the middle of the ranges of rates found in other studies. Harsh discipline was most likely directed at boys or children aged 7 years and committed by mothers, young fathers, or high and low socioeconomic status (SES) parents. The prevalence of maternal and paternal PA and CP declined with the children's age. Maternal and paternal SPA first increased and then decreased with child age. The frequency of the three types of maternal and paternal harsh discipline fluctuated depending on the age of the children. In addition, approximately 50% of the mothers and fathers who reported using severe forms of disciplinary practices also engaged in less severe forms of harsh disciplinary practices against their children. SPA generally coexisted with CP and PA, and CP was usually accompanied by PA; however, PA was more likely to occur independently compared with CP and SPA. Moreover, maternal harsh discipline coexisted with paternal harsh discipline to some extent. The coexistence decreased with increasing severity of parental harsh discipline and differed according to child gender. These findings highlight the importance of studying these three types of parental harsh discipline simultaneously and intervening in harsh discipline by mothers and fathers within the same family. Copyright © 2014 Elsevier Ltd. All rights reserved.

Highly-efficient, frequency-tripled Nd:YAG laser for spaceborne LIDARs

NASA Astrophysics Data System (ADS)

Treichel, R.; Hoffmann, H.-D.; Luttmann, J.; Morasch, V.; Nicklaus, K.; Wührer, C.

2017-11-01

For a spaceborne lidar a highly reliable, long living and efficient laser source is absolutely essential. Within the frame of the development of a laser source for the backscatter lidar ATLID, which will be flown on EarthCare mission, we setup and tested a predevelopment model of an injection-seeded, diode pumped, frequency tripled, pulsed high power Nd:YAG MOPA laser operating nominally at 100 Hz pulse repetition frequency. We also tested the burst operation mode. The excellent measured performance parameter will be introduced. The oscillator rod is longitudinally pumped from both sides. The oscillator has been operated with three cavity control methods: "Cavity Dither", "Pound-Drever-Hall" and "Adaptive Ramp & Fire". Especially the latter method is very suitable to operate the laser in harsh vibrating environment such in airplanes. The amplifier bases on the InnoSlab design concept. The constant keeping of a moderate fluence in the InnoSlab crystal permits excellent possibilities to scale the pulse energy to several 100 mJ. An innovative pump unit and optics makes the laser performance insensitive to inhomogeneous diode degradation and allows switching of additional redundant diodes. Further key features have been implemented in a FM design concept. The operational lifetime is extended by the implementation of internal redundancies for the most critical parts. The reliability is increased due to the higher margin onto the laser induced damage threshold by a pressurized housing. Additionally air-to-vacuum effects becomes obsolete. A high efficient heat removal concept has been implemented.

Challenges in photon-starved space astronomy in a harsh radiation environment using CCDs

NASA Astrophysics Data System (ADS)

Hall, David J.; Bush, Nathan; Murray, Neil; Gow, Jason; Clarke, Andrew; Burgon, Ross; Holland, Andrew

2015-09-01

The Charge Coupled Device (CCD) has a long heritage for imaging and spectroscopy in many space astronomy missions. However, the harsh radiation environment experienced in orbit creates defects in the silicon that capture the signal being transferred through the CCD. This radiation damage has a detrimental impact on the detector performance and requires carefully planned mitigation strategies. The ESA Gaia mission uses 106 CCDs, now orbiting around the second Lagrange point as part of the largest focal-plane ever launched. Following readout, signal electrons will be affected by the traps generated in the devices from the radiation environment and this degradation will be corrected for using a charge distortion model. ESA's Euclid mission will contain a focal plane of 36 CCDs in the VIS instrument. Moving further forwards, the World Space Observatory (WSO) UV spectrographs and the WFIRST-AFTA coronagraph intend to look at very faint sources in which mitigating the impact of traps on the transfer of single electron signals will be of great interest. Following the development of novel experimental and analysis techniques, one is now able to study the impact of radiation on the detector to new levels of detail. Through a combination of TCAD simulations, defect studies and device testing, we are now probing the interaction of single electrons with individual radiation-induced traps to analyse the impact of radiation in photon-starved applications.

Differential adaptation to a harsh granite outcrop habitat between sympatric Mimulus species.

PubMed

Ferris, Kathleen G; Willis, John H

2018-03-31

Understanding which environmental variables and traits underlie adaptation to harsh environments is difficult because many traits evolve simultaneously as populations or species diverge. Here, we investigate the ecological variables and traits that underlie Mimulus laciniatus' adaptation to granite outcrops compared to its sympatric, mesic-adapted progenitor, Mimulus guttatus. We use fine-scale measurements of soil moisture and herbivory to examine differences in selective forces between the species' habitats, and measure selection on flowering time, flower size, plant height, and leaf shape in a reciprocal transplant using M. laciniatus × M. guttatus F 4 hybrids. We find that differences in drought and herbivory drive survival differences between habitats, that M. laciniatus and M. guttatus are each better adapted to their native habitat, and differential habitat selection on flowering time, plant stature, and leaf shape. Although early flowering time, small stature, and lobed leaf shape underlie plant fitness in M. laciniatus' seasonally dry environment, increased plant size is advantageous in a competitive mesic environment replete with herbivores like M. guttatus'. Given that we observed divergent selection between habitats in the direction of species differences, we conclude that adaptation to different microhabitats is an important component of reproductive isolation in this sympatric species pair. © 2018 The Author(s). Evolution © 2018 The Society for the Study of Evolution.

Violence Exposure as a Mediator Between Parenting and Adolescent Mental Health.

PubMed

Moed, Anat; Gershoff, Elizabeth T; Bringewatt, Elizabeth H

2017-04-01

For youth exposed to community violence, parenting has been found to play a significant role in protecting adolescents from associated mental health symptoms. Yet little is known about the potential of parenting to prevent such exposure in the first place and thereby reduce the likelihood of adolescents' mental health symptoms. This study examined two parental practices that have often been examined as moderators, but not yet as predictors, of youth exposure to community violence associations with adolescent mental health, namely parental control and parental harshness. Analyses of self-reported data from 908 adolescents (M age  = 16.5, SD = 1.71; 52 % girls; 13 % non-Hispanic White) revealed that harsh parenting was indirectly associated with youth mental health symptoms through higher levels of exposure to community violence, whereas links between controlling parenting and mental health symptoms were either non-significant or mediated through lower levels of adolescent violence exposure. These findings highlight the potential positive role parental control may play by preventing adolescents from exposure to potentially dangerous situations. Conversely, our results suggest that harsh parenting appears to pose a risk for adolescents by driving youth away from the home environment and potentially into places where violence may be more prevalent.

Negative parenting behavior and childhood oppositional defiant disorder: differential moderation by positive and negative peer regard.

PubMed

Tung, Irene; Lee, Steve S

2014-01-01

Although negative parenting behavior and peer status are independently associated with childhood conduct problems (e.g., oppositional defiant disorder (ODD)), relatively little is known about their interplay, particularly in relation to differentiated measures of positive and negative peer regard. To improve the specificity of the association of negative parenting behavior and peer factors with ODD, we explored the potential interaction of parenting and peer status in a sample of 169 five-to ten-year-old ethnically diverse children with and without attention-deficit/hyperactivity disorder (ADHD) assessed using multiple measures (i.e., rating scales, interview) and informants (i.e., parents, teachers). Controlling for children's age, sex, number of ADHD symptoms, and parents' race-ethnicity, peer acceptance inversely predicted and inconsistent discipline, harsh punishment, and peer rejection were each positively associated with ODD symptom severity. Interactive influences were also evident such that inconsistent discipline and harsh punishment each predicted elevated ODD but only among children experiencing low peer acceptance or high peer rejection. These findings suggest that supportive environments, including peer acceptance, may protect children from negative outcomes associated with inconsistent discipline and harsh punishment. Findings are integrated with theories of social support, and we additionally consider implications for intervention and prevention. © 2013 Wiley Periodicals, Inc.

Dynamic Conservation of Date Palms: The Future of a Genetic Resource at the Nexus of Climate Change, Desertification and Salinity Stress in Oasis Ecosystems

USDA-ARS?s Scientific Manuscript database

The date palm (Phoenix dactylifera) is the only indigenous, wild desert plant definitely domesticated in its native harsh environment, and along with the camel (Camelus dromedarius), was responsible for opening the vast desert territories for human activity and the development of oasis ecosystems, w...

Medical Aspects of Harsh Environments. Volume 2

DTIC Science & Technology

2002-01-01

Fulco CS, Trad LA, Forte VA, Cymerman A. Altitude acclimatization attenuates plasma ammonia accumulation during submaximal exercise. J Appl Physiol...107 and decreased ammonia accumulation66 and dependence on muscle glyco- gen.109 These hypoxia-produced changes in oxygen delivery and metabolic profile...Young PM, Rock PB, Fulco CS, Trad LA, Forte VA Jr, Cymerman A. Altitude acclimatization attenuates plasma ammonia accumulation during submaximal

High expansion, lithium corrosion resistant sealing glasses

DOEpatents

Brow, Richard K.; Watkins, Randall D.

1991-01-01

Glass compositions containing CaO, Al.sub.2 O.sub.3, B.sub.2 O.sub.3, SrO and BaO in various combinations of mole % are provided. These compositions are capable of forming stable glass-to-metal seals with pin materials of 446 Stainless Steel and Alloy-52 rather than molybdenum, for use in harsh chemical environments, specifically in lithium batteries.

High expansion, lithium corrosion resistant sealing glasses

DOEpatents

Brow, R.K.; Watkins, R.D.

1991-06-04

Glass compositions containing CaO, Al[sub 2]O[sub 3], B[sub 2]O[sub 3], SrO and BaO in various combinations of mole % are provided. These compositions are capable of forming stable glass-to-metal seals with pin materials of 446 Stainless Steel and Alloy-52 rather than molybdenum, for use in harsh chemical environments, specifically in lithium batteries.