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Sample records for thermal sensor technique

  1. Discrimination techniques employing both reflective and thermal multispectral signals. [for remote sensor technology

    Science.gov (United States)

    Malila, W. A.; Crane, R. B.; Richardson, W.

    1973-01-01

    Recent improvements in remote sensor technology carry implications for data processing. Multispectral line scanners now exist that can collect data simultaneously and in registration in multiple channels at both reflective and thermal (emissive) wavelengths. Progress in dealing with two resultant recognition processing problems is discussed: (1) More channels mean higher processing costs; to combat these costs, a new and faster procedure for selecting subsets of channels has been developed. (2) Differences between thermal and reflective characteristics influence recognition processing; to illustrate the magnitude of these differences, some explanatory calculations are presented. Also introduced, is a different way to process multispectral scanner data, namely, radiation balance mapping and related procedures. Techniques and potentials are discussed and examples presented.

  2. Sensors, Volume 4, Thermal Sensors

    Science.gov (United States)

    Scholz, Jorg; Ricolfi, Teresio

    1996-12-01

    'Sensors' is the first self-contained series to deal with the whole area of sensors. It describes general aspects, technical and physical fundamentals, construction, function, applications and developments of the various types of sensors. This volume describes the construction and applicational aspects of thermal sensors while presenting a rigorous treatment of the underlying physical principles. It provides a unique overview of the various categories of sensors as well as of specific groups, e.g. temperature sensors (resistance thermometers, thermocouples, and radiation thermometers), noise and acoustic thermometers, heat-flow and mass-flow sensors. Specific facettes of applications are presented by specialists from different fields including process control, automotive technology and cryogenics. This volume is an indispensable reference work and text book for both specialists and newcomers, researchers and developers.

  3. Thermal flow micro sensors

    NARCIS (Netherlands)

    Elwenspoek, Michael Curt

    1999-01-01

    A review is given on sensors fabricated by silicon micromachining technology using the thermal domain for the measurement of fluid flow. Attention is paid especially to performance and geometry of the sensors. Three basic types of thermal flow sensors are discussed: anemometers, calorimetric flow

  4. REAL TIME PULVERISED COAL FLOW SOFT SENSOR FOR THERMAL POWER PLANTS USING EVOLUTIONARY COMPUTATION TECHNIQUES

    Directory of Open Access Journals (Sweden)

    B. Raja Singh

    2015-01-01

    Full Text Available Pulverised coal preparation system (Coal mills is the heart of coal-fired power plants. The complex nature of a milling process, together with the complex interactions between coal quality and mill conditions, would lead to immense difficulties for obtaining an effective mathematical model of the milling process. In this paper, vertical spindle coal mills (bowl mill that are widely used in coal-fired power plants, is considered for the model development and its pulverised fuel flow rate is computed using the model. For the steady state coal mill model development, plant measurements such as air-flow rate, differential pressure across mill etc., are considered as inputs/outputs. The mathematical model is derived from analysis of energy, heat and mass balances. An Evolutionary computation technique is adopted to identify the unknown model parameters using on-line plant data. Validation results indicate that this model is accurate enough to represent the whole process of steady state coal mill dynamics. This coal mill model is being implemented on-line in a 210 MW thermal power plant and the results obtained are compared with plant data. The model is found accurate and robust that will work better in power plants for system monitoring. Therefore, the model can be used for online monitoring, fault detection, and control to improve the efficiency of combustion.

  5. Thermal Flow Sensors for Harsh Environments.

    Science.gov (United States)

    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.

  6. Thermal Flow Sensors for Harsh Environments

    Directory of Open Access Journals (Sweden)

    Vivekananthan Balakrishnan

    2017-09-01

    Full Text Available 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.

  7. Thermal microphotonic sensor and sensor array

    Science.gov (United States)

    Watts, Michael R [Albuquerque, NM; Shaw, Michael J [Tijeras, NM; Nielson, Gregory N [Albuquerque, NM; Lentine, Anthony L [Albuquerque, NM

    2010-02-23

    A thermal microphotonic sensor is disclosed for detecting infrared radiation using heat generated by the infrared radiation to shift the resonant frequency of an optical resonator (e.g. a ring resonator) to which the heat is coupled. The shift in the resonant frequency can be determined from light in an optical waveguide which is evanescently coupled to the optical resonator. An infrared absorber can be provided on the optical waveguide either as a coating or as a plate to aid in absorption of the infrared radiation. In some cases, a vertical resonant cavity can be formed about the infrared absorber to further increase the absorption of the infrared radiation. The sensor can be formed as a single device, or as an array for imaging the infrared radiation.

  8. Practical Use Technique of Sensor

    International Nuclear Information System (INIS)

    Hwang, Gyu Seop

    1985-11-01

    This book tells of practical use technology of sensor, introducing the recent trend of sensor for electronic industry, IC temperature sensor, radiation temperature sensor of surface acoustic wave, optical fiber temperature sensor, a polyelectrolyte film humidity sensor, semiconductor pressure sensor for industrial instrumentation, silicon integration pressure sensor, thick film humidity sensor and its application, photo sensor reflection type, and color sensor. It also deals with sensor for FA, sensor for a robot and sensor for the chemical industry.

  9. Practical Use Technique of Sensor

    Energy Technology Data Exchange (ETDEWEB)

    Hwang, Gyu Seop

    1985-11-15

    This book tells of practical use technology of sensor, introducing the recent trend of sensor for electronic industry, IC temperature sensor, radiation temperature sensor of surface acoustic wave, optical fiber temperature sensor, a polyelectrolyte film humidity sensor, semiconductor pressure sensor for industrial instrumentation, silicon integration pressure sensor, thick film humidity sensor and its application, photo sensor reflection type, and color sensor. It also deals with sensor for FA, sensor for a robot and sensor for the chemical industry.

  10. Pressure-Sensor Assembly Technique

    Science.gov (United States)

    Pruzan, Daniel A.

    2003-01-01

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

  11. Thermal infrared panoramic imaging sensor

    Science.gov (United States)

    Gutin, Mikhail; Tsui, Eddy K.; Gutin, Olga; Wang, Xu-Ming; Gutin, Alexey

    2006-05-01

    Panoramic cameras offer true real-time, 360-degree coverage of the surrounding area, valuable for a variety of defense and security applications, including force protection, asset protection, asset control, security including port security, perimeter security, video surveillance, border control, airport security, coastguard operations, search and rescue, intrusion detection, and many others. Automatic detection, location, and tracking of targets outside protected area ensures maximum protection and at the same time reduces the workload on personnel, increases reliability and confidence of target detection, and enables both man-in-the-loop and fully automated system operation. Thermal imaging provides the benefits of all-weather, 24-hour day/night operation with no downtime. In addition, thermal signatures of different target types facilitate better classification, beyond the limits set by camera's spatial resolution. The useful range of catadioptric panoramic cameras is affected by their limited resolution. In many existing systems the resolution is optics-limited. Reflectors customarily used in catadioptric imagers introduce aberrations that may become significant at large camera apertures, such as required in low-light and thermal imaging. Advantages of panoramic imagers with high image resolution include increased area coverage with fewer cameras, instantaneous full horizon detection, location and tracking of multiple targets simultaneously, extended range, and others. The Automatic Panoramic Thermal Integrated Sensor (APTIS), being jointly developed by Applied Science Innovative, Inc. (ASI) and the Armament Research, Development and Engineering Center (ARDEC) combines the strengths of improved, high-resolution panoramic optics with thermal imaging in the 8 - 14 micron spectral range, leveraged by intelligent video processing for automated detection, location, and tracking of moving targets. The work in progress supports the Future Combat Systems (FCS) and the

  12. Soft Thermal Sensor with Mechanical Adaptability.

    Science.gov (United States)

    Yang, Hui; Qi, Dianpeng; Liu, Zhiyuan; Chandran, Bevita K; Wang, Ting; Yu, Jiancan; Chen, Xiaodong

    2016-11-01

    A soft thermal sensor with mechanical adaptability is fabricated by the combination of single-wall carbon nanotubes with carboxyl groups and self-healing polymers. This study demonstrates that this soft sensor has excellent thermal response and mechanical adaptability. It shows tremendous promise for improving the service life of soft artificial-intelligence robots and protecting thermally sensitive electronics from the risk of damage by high temperature. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Thermal measurements and inverse techniques

    CERN Document Server

    Orlande, Helcio RB; Maillet, Denis; Cotta, Renato M

    2011-01-01

    With its uncommon presentation of instructional material regarding mathematical modeling, measurements, and solution of inverse problems, Thermal Measurements and Inverse Techniques is a one-stop reference for those dealing with various aspects of heat transfer. Progress in mathematical modeling of complex industrial and environmental systems has enabled numerical simulations of most physical phenomena. In addition, recent advances in thermal instrumentation and heat transfer modeling have improved experimental procedures and indirect measurements for heat transfer research of both natural phe

  14. Airborne Sensor Thermal Management Solution

    Energy Technology Data Exchange (ETDEWEB)

    Ng, K. K. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2015-06-03

    The customer wants to outfit aircraft (de Havilland Twin Otter) with optical sensors. In previous product generations the sensor line-of-sight direction was fixed – the sensor’s direction relied on the orientation of the aircraft. The next generation sensor will be packaged in a rotatable turret so that the line-of-sight is reasonably independent of the aircraft’s orientation. This turret will be mounted on a boom protruding from the side of the aircraft. The customer wants to outfit aircraft (de Havilland Twin Otter) with optical sensors. In previous product generations the sensor line-of-sight direction was fixed – the sensor’s direction relied on the orientation of the aircraft. The next generation sensor will be packaged in a rotatable turret so that the line-of-sight is reasonably independent of the aircraft’s orientation. This turret will be mounted on a boom protruding from the side of the aircraft.

  15. Distributed thermal micro sensors for fluid flow

    NARCIS (Netherlands)

    van Baar, J.J.J.

    2002-01-01

    In this thesis thermal sensor-actuator structures are proposed for measuring the parameters pressure p, dynamic viscosity μ, thermal conductivity , specific heat c, density and the fluid velocity v. In this chapter examples will be given of the added value of many identical simple elements and the

  16. Temperature-modulated direct thermoelectric gas sensors: thermal modeling and results for fast hydrocarbon sensors

    International Nuclear Information System (INIS)

    Rettig, Frank; Moos, Ralf

    2009-01-01

    Direct thermoelectric gas sensors are a promising alternative to conductometric gas sensors. For accurate results, a temperature modulation technique in combination with a regression analysis is advantageous. However, the thermal time constant of screen-printed sensors is quite large. As a result, up to now the temperature modulation frequency (20 mHz) has been too low and the corresponding principle-related response time (50 s) has been too high for many applications. With a special design, respecting the physical properties of thermal waves and the use of signal processing similar to a lock-in-amplifier, it is possible to achieve response times of about 1 s. As a result, direct thermoelectric gas sensors with SnO 2 as a gas-sensitive material respond fast and are reproducible to the propane concentration in the ambient atmosphere. Due to the path-independent behavior of the thermovoltage and the temperature, the measured thermopower of two sensors is almost identical

  17. Thermal infrared remote sensing sensors, methods, applications

    CERN Document Server

    Kuenzer, Claudia

    2013-01-01

    This book provides a comprehensive overview of the state of the art in the field of thermal infrared remote sensing. Temperature is one of the most important physical environmental variables monitored by earth observing remote sensing systems. Temperature ranges define the boundaries of habitats on our planet. Thermal hazards endanger our resources and well-being. In this book renowned international experts have contributed chapters on currently available thermal sensors as well as innovative plans for future missions. Further chapters discuss the underlying physics and image processing techni

  18. Thermal physics of transition edge sensor arrays

    International Nuclear Information System (INIS)

    Hoevers, H.F.C.

    2006-01-01

    Thermal transport in transition edge sensor (TES)-based microcalorimeter arrays is reviewed. The fundamentals of thermal conductance in Si 3 N 4 membranes are discussed and the magnitude of the electron-phonon coupling and Kapitza coupling in practical devices is summarized. Next, the thermal transport in high-stopping power and low-heat capacity absorbers, required for arrays of TES microcalorimeters, is discussed in combination with a performance analysis of detectors with mushroom-absorbers. Finally, the phenomenology of unexplained excess noise, observed in both Mo- and Ti-based TESs, is briefly summarized and related with the coupling of the TES to the heat bath

  19. A Micro-Thermal Sensor for Focal Therapy Applications

    Science.gov (United States)

    Natesan, Harishankar; Hodges, Wyatt; Choi, Jeunghwan; Lubner, Sean; Dames, Chris; Bischof, John

    2016-02-01

    There is an urgent need for sensors deployed during focal therapies to inform treatment planning and in vivo monitoring in thin tissues. Specifically, the measurement of thermal properties, cooling surface contact, tissue thickness, blood flow and phase change with mm to sub mm accuracy are needed. As a proof of principle, we demonstrate that a micro-thermal sensor based on the supported “3ω” technique can achieve this in vitro under idealized conditions in 0.5 to 2 mm thick tissues relevant to cryoablation of the pulmonary vein (PV). To begin with “3ω” sensors were microfabricated onto flat glass as an idealization of a focal probe surface. The sensor was then used to make new measurements of ‘k’ (W/m.K) of porcine PV, esophagus, and phrenic nerve, all needed for PV cryoabalation treatment planning. Further, by modifying the sensor use from traditional to dynamic mode new measurements related to tissue vs. fluid (i.e. water) contact, fluid flow conditions, tissue thickness, and phase change were made. In summary, the in vitro idealized system data presented is promising and warrants future work to integrate and test supported “3ω” sensors on in vivo deployed focal therapy probe surfaces (i.e. balloons or catheters).

  20. Development of techniques for fabrication of film probe sensor assembly

    International Nuclear Information System (INIS)

    Moorhead, A.J.

    1982-10-01

    Pulsed laser welding and brazing techniques were developed for fabrication of sensors designed to measure liquid film properties in out-of-reactor safety tests that simulate a loss-of-coolant accident in a pressurized-water nuclear reactor. These sensors were made possible by a unique ceramic-to-metal seal system based on a cermet insulator and a brazing filler metal, both developed at ORNL. This seal system was shown to resist steam to an exposure of at least 100 h at 700 0 C (1292 0 F) and to resist repetitive thermal transients of 300 0 C/s (540 0 F). Procedures were also developed for induction brazing the instrumentation cables to a stainless steel end cap and for laser welding this component to the brazed sensor body itself. Cable end seals and sensor bodies fabricated with these designs and techniques maintained excellent helium leaktightness ( -6 cm 3 /s) after 20 severe thermal shock tests from 500 0 C air into water at 80 0 C

  1. Cooperative Technique Based on Sensor Selection in Wireless Sensor Network

    Directory of Open Access Journals (Sweden)

    ISLAM, M. R.

    2009-02-01

    Full Text Available An energy efficient cooperative technique is proposed for the IEEE 1451 based Wireless Sensor Networks. Selected numbers of Wireless Transducer Interface Modules (WTIMs are used to form a Multiple Input Single Output (MISO structure wirelessly connected with a Network Capable Application Processor (NCAP. Energy efficiency and delay of the proposed architecture are derived for different combination of cluster size and selected number of WTIMs. Optimized constellation parameters are used for evaluating derived parameters. The results show that the selected MISO structure outperforms the unselected MISO structure and it shows energy efficient performance than SISO structure after a certain distance.

  2. Performance evaluation of multi-sensor data fusion technique for ...

    Indian Academy of Sciences (India)

    R. Narasimhan (Krishtel eMaging) 1461 1996 Oct 15 13:05:22

    Multi-sensor data fusion; Test Range application; trajectory .... Kalman filtering technique utilizes the noise statistics of the underlying system under con- ..... Hall D L 1992 Mathematical techniques in multi-sensor data fusion (Boston, MA: ...

  3. High sensitivity thermal sensors on insulating diamond

    Energy Technology Data Exchange (ETDEWEB)

    Job, R. [Fernuniversitaet Hagen (Gesamthochschule) (Germany). Electron. Devices; Denisenko, A.V. [Fernuniversitaet Hagen (Gesamthochschule) (Germany). Electron. Devices; Zaitsev, A.M. [Fernuniversitaet Hagen (Gesamthochschule) (Germany). Electron. Devices; Melnikov, A.A. [Belarussian State Univ., Minsk (Belarus). HEII and FD; Werner, M. [VDI/VDE-IT, Teltow (Germany); Fahrner, W.R. [Fernuniversitaet Hagen (Gesamthochschule) (Germany). Electron. Devices

    1996-12-15

    Diamond is a promising material to develop sensors for applications in harsh environments. To increase the sensitivity of diamond temperature sensors the effect of thermionic hole emission (TE) over an energetic barrier formed in the interface between highly boron-doped p-type and intrinsic insulating diamond areas has been suggested. To study the TE of holes a p-i-p diode has been fabricated and analyzed by electrical measurements in the temperature range between 300 K and 700 K. The experimental results have been compared with numerical simulations of its electrical characteristics. Based on a model of the thermionic emission of carriers into an insulator it has been suggested that the temperature sensitivity of the p-i-p diode on diamond is strongly affected by the re-emission of holes from a group of donor-like traps located at a level of 0.7-1.0 eV above the valence band. The mechanism of thermal activation of the current includes a spatial redistribution of the potential, which results in the TE regime from a decrease of the immobilized charge of the ionized traps within the i-zone of the diode and the correspondent lowering of the forward biased barrier. The characteristics of the p-i-p diode were studied with regard to temperature sensor applications. The temperature coefficient of resistance (TCR=-0.05 K{sup -1}) for temperatures above 600 K is about four times larger than the maximal attainable TCR for conventional boron-doped diamond resistors. (orig.)

  4. A thermal comparator sensor for measuring autogenous deformation in hardening Portland cement paste

    DEFF Research Database (Denmark)

    Østergaard, Thomas; Jensen, Ole Mejlhede

    2003-01-01

    This paper describes a simple and accurate experimental device specially developed to measure autogenous deformation in hardening cement-based materials. The measuring system consists of a so-called thermal comparator sensor and a modular thermostatically controlled system. The operating principle...... of the thermal comparator is based on thermal expansion of aluminium. A particular characteristic of the measuring system is the fixation of the thermal comparator sensor to the deforming specimen. The modular system ensures effective thermostatic control of the hydrating cement paste samples. The technique...... allows continuous measurement with high accuracy of the linear deformation as well as determination of the activation energy of autogenous deformation....

  5. Calibration of non-ideal thermal conductivity sensors

    Directory of Open Access Journals (Sweden)

    N. I. Kömle

    2013-04-01

    Full Text Available A popular method for measuring the thermal conductivity of solid materials is the transient hot needle method. It allows the thermal conductivity of a solid or granular material to be evaluated simply by combining a temperature measurement with a well-defined electrical current flowing through a resistance wire enclosed in a long and thin needle. Standard laboratory sensors that are typically used in laboratory work consist of very thin steel needles with a large length-to-diameter ratio. This type of needle is convenient since it is mathematically easy to derive the thermal conductivity of a soft granular material from a simple temperature measurement. However, such a geometry often results in a mechanically weak sensor, which can bend or fail when inserted into a material that is harder than expected. For deploying such a sensor on a planetary surface, with often unknown soil properties, it is necessary to construct more rugged sensors. These requirements can lead to a design which differs substantially from the ideal geometry, and additional care must be taken in the calibration and data analysis. In this paper we present the performance of a prototype thermal conductivity sensor designed for planetary missions. The thermal conductivity of a suite of solid and granular materials was measured both by a standard needle sensor and by several customized sensors with non-ideal geometry. We thus obtained a calibration curve for the non-ideal sensors. The theory describing the temperature response of a sensor with such unfavorable length-to-diameter ratio is complicated and highly nonlinear. However, our measurements reveal that over a wide range of thermal conductivities there is an almost linear relationship between the result obtained by the standard sensor and the result derived from the customized, non-ideal sensors. This allows for the measurement of thermal conductivity values for harder soils, which are not easily accessible when using

  6. Wearable Sweat Rate Sensors for Human Thermal Comfort Monitoring.

    Science.gov (United States)

    Sim, Jai Kyoung; Yoon, Sunghyun; Cho, Young-Ho

    2018-01-19

    We propose watch-type sweat rate sensors capable of automatic natural ventilation by integrating miniaturized thermo-pneumatic actuators, and experimentally verify their performances and applicability. Previous sensors using natural ventilation require manual ventilation process or high-power bulky thermo-pneumatic actuators to lift sweat rate detection chambers above skin for continuous measurement. The proposed watch-type sweat rate sensors reduce operation power by minimizing expansion fluid volume to 0.4 ml through heat circuit modeling. The proposed sensors reduce operation power to 12.8% and weight to 47.6% compared to previous portable sensors, operating for 4 hours at 6 V batteries. Human experiment for thermal comfort monitoring is performed by using the proposed sensors having sensitivity of 0.039 (pF/s)/(g/m 2 h) and linearity of 97.9% in human sweat rate range. Average sweat rate difference for each thermal status measured in three subjects shows (32.06 ± 27.19) g/m 2 h in thermal statuses including 'comfortable', 'slightly warm', 'warm', and 'hot'. The proposed sensors thereby can discriminate and compare four stages of thermal status. Sweat rate measurement error of the proposed sensors is less than 10% under air velocity of 1.5 m/s corresponding to human walking speed. The proposed sensors are applicable for wearable and portable use, having potentials for daily thermal comfort monitoring applications.

  7. Differential sensor in front photopyroelectric technique: I. Theory

    Energy Technology Data Exchange (ETDEWEB)

    Ivanov, R; Moreno, I [Facultad de Fisica, Universidad Autonoma de Zacatecas, Calz. Solidaridad Esquina Paseo de la Bufa s/n, C.P. 98060, Zacatecas, Zac. (Mexico); Gutierrez-Juarez, G [Instituto de Fisica, Universidad de Guanajuato, Loma del Bosque 103, Lomas del Campestre, C.P. 37150, Leon, Gto. (Mexico); Pichardo-Molina, J L [Centro de Investigaciones en Optica, Loma del Bosque 115, Lomas del Campestre, C.P. 37150, Leon, Gto. (Mexico); Cruz-Orea, A [Departamento de Fisica, CINVESTAV-IPN, Av. IPN 2508, San Pedro Zacatenco, C.P. 07360, Mexico D.F. (Mexico); MarIn, E [Centro de Investigacion en Ciencia Aplicada y TecnologIa Avanzada, Instituto Politecnico Nacional, LegarIa 694, Colonia Irrigacion, C.P. 11500, Mexico D. F. (Mexico)], E-mail: rumen@planck.reduaz.mx

    2008-04-21

    In this paper the theory of the differential front photopyroelectric technique is developed. The thermal effusivity measurements of a sample through photopyroelectric direct (no-differential) experiments do not have sufficient resolution and accuracy to detect small changes in the thermal effusivity. To assess minor variations in this thermal magnitude, differential methods should be used. These methods compare properties of a reference sample and another unknown sample, which are placed separately in both halves of the differential cell. It is shown that in order to achieve better metrological properties of the differential measurement and electromagnetic interference immunity, the signals of both halves must be subtracted directly at the output of the two parallel connected pyroelectric sensors. The thickness of the samples should have the maximum possible value, at least 10 times higher than the thermal diffusion length for minimum frequency. The results of numerical simulations for the amplitude, phase, real and imaginary parts with water as a reference sample and the other sample with a thermal effusivity very close to that of water (contaminated water) are presented. These results show that measurements should be made in the nearly ideal voltage mode, which ensures a better signal-to-noise ratio than the ideal current mode.

  8. Differential sensor in front photopyroelectric technique: I. Theory

    International Nuclear Information System (INIS)

    Ivanov, R; Moreno, I; Gutierrez-Juarez, G; Pichardo-Molina, J L; Cruz-Orea, A; MarIn, E

    2008-01-01

    In this paper the theory of the differential front photopyroelectric technique is developed. The thermal effusivity measurements of a sample through photopyroelectric direct (no-differential) experiments do not have sufficient resolution and accuracy to detect small changes in the thermal effusivity. To assess minor variations in this thermal magnitude, differential methods should be used. These methods compare properties of a reference sample and another unknown sample, which are placed separately in both halves of the differential cell. It is shown that in order to achieve better metrological properties of the differential measurement and electromagnetic interference immunity, the signals of both halves must be subtracted directly at the output of the two parallel connected pyroelectric sensors. The thickness of the samples should have the maximum possible value, at least 10 times higher than the thermal diffusion length for minimum frequency. The results of numerical simulations for the amplitude, phase, real and imaginary parts with water as a reference sample and the other sample with a thermal effusivity very close to that of water (contaminated water) are presented. These results show that measurements should be made in the nearly ideal voltage mode, which ensures a better signal-to-noise ratio than the ideal current mode

  9. Miniaturized thermal flow sensor with planar-integrated sensor structures on semicircular surface channels

    NARCIS (Netherlands)

    Dijkstra, Marcel; de Boer, Meint J.; Berenschot, Johan W.; Lammerink, Theodorus S.J.; Wiegerink, Remco J.; Elwenspoek, Michael Curt

    2008-01-01

    A calorimetric miniaturized flow sensor was realized with a linear sensor response measured for water flow up to flow rates in the order of 300 nl min-1. A versatile technological concept is used to realize a sensor with a thermally isolated freely suspended silicon-rich silicon-nitride microchannel

  10. Solar Probe Plus MAG Sensor Thermal Design for Low Heater Power and Extreme Thermal Environment

    Science.gov (United States)

    Choi, Michael K.

    2015-01-01

    The heater power available for the Solar Probe Plus FIELDS MAG sensor is less than half of the heritage value for other missions. Nominally the MAG sensors are in the spacecraft's umbra. In the worst hot case, approximately 200 spacecraft communication downlinks, up to 10 hours each, are required at 0.7 AU. These downlinks require the spacecraft to slew 45 deg. about the Y-axis, exposing the MAG sensors and boom to sunlight. This paper presents the thermal design to meet the MAG sensor thermal requirements in the extreme thermal environment and with low heater power. A thermal balance test on the MAG sensor engineering model has verified the thermal design and correlated the thermal model for flight temperature predictions.

  11. Electropyroelectric technique for measurement of the thermal effusivity of liquids

    Energy Technology Data Exchange (ETDEWEB)

    Ivanov, R; Moreno, I; Araujo, C [Facultad de Fisica, Universidad Autonoma de Zacatecas, Calz. Solidaridad Esquina Paseo de la Bufa s/n, C. P. 98060, Zacatecas, Zac. (Mexico); Marin, E, E-mail: emarin63@yahoo.e, E-mail: emarinm@ipn.m [Centro de Investigacion en Ciencia Aplicada y TecnologIa Avanzada, Instituto Politecnico Nacional, LegarIa 694, Colonia Irrigacion, C. P. 11500, Mexico D. F. (Mexico)

    2010-06-09

    The photopyroelectric method has been recognized as a reliable and useful tool for the measurement of the thermal properties of condensed matter samples. Usually the photothermal signal is generated using intensity modulated light beams, whose amplitudes are difficult to maintain stable. In this paper we describe a variant of this technique that uses amplitude modulated electrical current as excitation source, via Joule heating of the metal contact on one side of the pyroelectric sensor. The possibilities of this method, called by us the electropyroelectric technique, for thermal effusivity measurements of liquid samples are shown using test samples of distilled water, ethanol and glycerine. The results obtained for this parameter agree well with the values reported in the literature. Our measurement uncertainties are about 3%, a fact that opens several possible applications.

  12. Electropyroelectric technique for measurement of the thermal effusivity of liquids

    International Nuclear Information System (INIS)

    Ivanov, R; Moreno, I; Araujo, C; Marin, E

    2010-01-01

    The photopyroelectric method has been recognized as a reliable and useful tool for the measurement of the thermal properties of condensed matter samples. Usually the photothermal signal is generated using intensity modulated light beams, whose amplitudes are difficult to maintain stable. In this paper we describe a variant of this technique that uses amplitude modulated electrical current as excitation source, via Joule heating of the metal contact on one side of the pyroelectric sensor. The possibilities of this method, called by us the electropyroelectric technique, for thermal effusivity measurements of liquid samples are shown using test samples of distilled water, ethanol and glycerine. The results obtained for this parameter agree well with the values reported in the literature. Our measurement uncertainties are about 3%, a fact that opens several possible applications.

  13. A thermal plasmonic sensor platform: resistive heating of nanohole arrays.

    Science.gov (United States)

    Virk, Mudassar; Xiong, Kunli; Svedendahl, Mikael; Käll, Mikael; Dahlin, Andreas B

    2014-06-11

    We have created a simple and efficient thermal plasmonic sensor platform by letting a DC current heat plasmonic nanohole arrays. The sensor can be used to determine thermodynamic parameters in addition to monitoring molecular reactions in real-time. As an application example, we use the thermal sensor to determine the kinetics and activation energy for desorption of thiol monolayers on gold. Further, the temperature of the metal can be measured optically by the spectral shift of the bonding surface plasmon mode (0.015 nm/K). We show that this resonance shift is caused by thermal lattice expansion, which reduces the plasma frequency of the metal. The sensor is also used to determine the thin film thermal expansion coefficient through a theoretical model for the expected resonance shift.

  14. Note: Development of a microfabricated sensor to measure thermal conductivity of picoliter scale liquid samples.

    Science.gov (United States)

    Park, Byoung Kyoo; Yi, Namwoo; Park, Jaesung; Kim, Dongsik

    2012-10-01

    This paper presents a thermal analysis device, which can measure thermal conductivity of picoliter scale liquid sample. We employ the three omega method with a microfabricated AC thermal sensor with nanometer width heater. The liquid sample is confined by a micro-well structure fabricated on the sensor surface. The performance of the instrument was verified by measuring the thermal conductivity of 27-picoliter samples of de-ionized (DI) water, ethanol, methanol, and DI water-ethanol mixtures with accuracies better than 3%. Furthermore, another analytical scheme allows real-time thermal conductivity measurement with 5% accuracy. To the best of our knowledge, this technique requires the smallest volume of sample to measure thermal property ever.

  15. Thermal-Signature-Based Sleep Analysis Sensor

    Directory of Open Access Journals (Sweden)

    Ali Seba

    2017-10-01

    Full Text Available This paper addresses the development of a new technique in the sleep analysis domain. Sleep is defined as a periodic physiological state during which vigilance is suspended and reactivity to external stimulations diminished. We sleep on average between six and nine hours per night and our sleep is composed of four to six cycles of about 90 min each. Each of these cycles is composed of a succession of several stages of sleep that vary in depth. Analysis of sleep is usually done via polysomnography. This examination consists of recording, among other things, electrical cerebral activity by electroencephalography (EEG, ocular movements by electrooculography (EOG, and chin muscle tone by electromyography (EMG. Recordings are made mostly in a hospital, more specifically in a service for monitoring the pathologies related to sleep. The readings are then interpreted manually by an expert to generate a hypnogram, a curve showing the succession of sleep stages during the night in 30s epochs. The proposed method is based on the follow-up of the thermal signature that makes it possible to classify the activity into three classes: “awakening,” “calm sleep,” and “restless sleep”. The contribution of this non-invasive method is part of the screening of sleep disorders, to be validated by a more complete analysis of the sleep. The measure provided by this new system, based on temperature monitoring (patient and ambient, aims to be integrated into the tele-medicine platform developed within the framework of the Smart-EEG project by the SYEL–SYstèmes ELectroniques team. Analysis of the data collected during the first surveys carried out with this method showed a correlation between thermal signature and activity during sleep. The advantage of this method lies in its simplicity and the possibility of carrying out measurements of activity during sleep and without direct contact with the patient at home or hospitals.

  16. Thermal-dissipation sap flow sensors may not yield consistent sap-flux estimates over multiple years

    Science.gov (United States)

    Georgianne W. Moore; Barbara J. Bond; Julia A. Jones; Frederick C. Meinzer

    2010-01-01

    Sap flow techniques, such as thermal dissipation, involve an empirically derived relationship between sap flux and the temperature differential between a heated thermocouple and a nearby reference thermocouple inserted into the sapwood. This relationship has been widely tested but mostly with newly installed sensors. Increasingly, sensors are used for extended periods...

  17. Comparative Performance of PLZT and PVDF Pyroelectric Sensors Used to the Thermal Characterization of Liquid Samples

    Directory of Open Access Journals (Sweden)

    Gemima Lara Hernandez

    2013-01-01

    Full Text Available Among the photothermal methods, the photopyroelectric (PPE technique is a suitable method to determine thermal properties of different kinds of samples ranging from solids to liquids and gases. Polyvinylidene difluoride (PVDF is one of the most frequently used pyroelectric sensors in PPE technique but has the disadvantage that it can be easily deformed by the sample weight. This deformation could add a piezoelectric effect to the thermal parameters assessment; also PVDF has a narrow temperature operation range when compared with ceramic pyroelectric sensors. In order to minimize possible piezoelectric effects due to sensor deformation, a ceramic of lanthanum modified lead zirconate (PLZT was used as pyroelectric sensor in the PPE technique. Then, thermal diffusivity of some liquid samples was measured, by using the PPE configuration that denominated the thermal wave resonator cavity (TWRC, with a PLZT ceramic as pyroelectric detector. The performance obtained with the proposed ceramic in the TWRC configuration was compared with that obtained with PVDF by using the same configuration.

  18. Thermal property testing technique on micro specimen

    International Nuclear Information System (INIS)

    Baba, Tetsuya; Kishimoto, Isao; Taketoshi, Naoyuki

    2000-01-01

    This study aims at establishment of further development on some testing techniques on the nuclear advanced basic research accumulated by the National Research Laboratory of Metrology for ten years. For this purpose, a technology to test heat diffusion ratio and specific heat capacity of less than 3 mm in diameter and 1 mm in thickness of micro specimen and technology to test heat diffusion ratio at micro area of less than 1 mm in area along cross section of less than 10 mm in diameter of column specimen were developed to contribute to common basic technology supporting the nuclear power field. As a result, as an element technology to test heat diffusion ratio and specific heat capacity of the micro specimen, a specimen holding technique stably to hold a micro specimen with 3 mm in diameter could be developed. And, for testing the specific heat capacity by using the laser flush differential calorimetry, a technique to hold two specimen of 5 mm in diameter at their proximities was also developed. In addition, by promoting development of thermal property data base capable of storing thermal property data obtained in this study and with excellent workability in this 1998 fiscal year a data in/out-put program with graphical user interface could be prepared. (G.K.)

  19. Thermal effects of an ICL-based mid-infrared CH4 sensor within a wide atmospheric temperature range

    Science.gov (United States)

    Ye, Weilin; Zheng, Chuantao; Sanchez, Nancy P.; Girija, Aswathy V.; He, Qixin; Zheng, Huadan; Griffin, Robert J.; Tittel, Frank K.

    2018-03-01

    The thermal effects of an interband cascade laser (ICL) based mid-infrared methane (CH4) sensor that uses long-path absorption spectroscopy were studied. The sensor performance in the laboratory at a constant temperature of ∼25 °C was measured for 5 h and its Allan deviation was ∼2 ppbv with a 1 s averaging time. A LabVIEW-based simulation program was developed to study thermal effects on infrared absorption and a temperature compensation technique was developed to minimize these effects. An environmental test chamber was employed to investigate the thermal effects that occur in the sensor system with variation of the test chamber temperature between 10 and 30 °C. The thermal response of the sensor in a laboratory setting was observed using a 2.1 ppm CH4 standard gas sample. Indoor/outdoor CH4 measurements were conducted to evaluate the sensor performance within a wide atmospheric temperature range.

  20. Thermal design and analysis of high power star sensors

    Directory of Open Access Journals (Sweden)

    Fan Jiang

    2015-09-01

    Full Text Available The requirement for the temperature stability is very high in the star sensors as the high precision needs for the altitude information. Thermal design and analysis thus is important for the high power star sensors and their supporters. CCD, normally with Peltier thermoelectric cooler (PTC, is the most important sensor component in the star sensors, which is also the main heat source in the star sensors suite. The major objective for the thermal design in this paper is to design a radiator to optimize the heat diffusion for CCD and PTC. The structural configuration of star sensors, the heat sources and orbit parameters were firstly introduced in this paper. The influences of the geometrical parameters and coating material characteristics of radiators on the heat diffusion were investigated by heat flux analysis. Carbon–carbon composites were then chosen to improve the thermal conductivity for the sensor supporters by studying the heat transfer path. The design is validated by simulation analysis and experiments on orbit. The satellite data show that the temperatures of three star sensors are from 17.8 °C to 19.6 °C, while the simulation results are from 18.1 °C to 20.1 °C. The temperatures of radiator are from 16.1 °C to 16.8 °C and the corresponding simulation results are from 16.0 °C to 16.5 °C. The temperature variety of each star sensor is less than 2 °C, which satisfies the design objectives.

  1. Security Techniques for Sensor Systems and the Internet of Things

    Science.gov (United States)

    Midi, Daniele

    2016-01-01

    Sensor systems are becoming pervasive in many domains, and are recently being generalized by the Internet of Things (IoT). This wide deployment, however, presents significant security issues. We develop security techniques for sensor systems and IoT, addressing all security management phases. Prior to deployment, the nodes need to be hardened. We…

  2. Thermal micropressure sensor for pressure monitoring in a minute package

    International Nuclear Information System (INIS)

    Wang, S. N.; Mizuno, K.; Fujiyoshi, M.; Funabashi, H.; Sakata, J.

    2001-01-01

    A thermal micropressure sensor suitable for pressure measurements in the range from 7x10 -3 to 1x10 5 Pa has been fabricated by forming a titanium (Ti) thin-film resistor on a floating nondoped silica glass membrane, with the sensing area being as small as 60 μmx60 μm. The sensor performance is raised by: (1) increasing the ratio of gaseous thermal conduction in the total thermal conduction by sensor structure design; (2) compensating the effect of ambient-temperature drift by using a reference resistor located close to the sensing element but directly on the silicon substrate; and (3) utilizing an optimized novel constant-bias Wheatstone bridge circuit. By choosing a proper bias voltage, which can be found by simple calculation, the circuit extracts information on gaseous thermal conduction from the directly measurable total heat loss of the heated sensing element. The sensor was enclosed in a metal package with a capacity of about 0.5 ml by projection welding and was successfully applied to monitoring the pressure in the minute space

  3. Thermal infrared sensors for postharvest deficit irrigation of peach

    Science.gov (United States)

    California has been in a historic drought and the lack of water has been a major problem for agriculture especially for crops that depend on irrigation. A multi-year field study was carried out to demonstrate the feasibility of applying thermal infrared sensors for managing deficit irrigation in an ...

  4. On-Line Temperature Estimation for Noisy Thermal Sensors Using a Smoothing Filter-Based Kalman Predictor

    Directory of Open Access Journals (Sweden)

    Xin Li

    2018-02-01

    Full Text Available Dynamic thermal management (DTM mechanisms utilize embedded thermal sensors to collect fine-grained temperature information for monitoring the real-time thermal behavior of multi-core processors. However, embedded thermal sensors are very susceptible to a variety of sources of noise, including environmental uncertainty and process variation. This causes the discrepancies between actual temperatures and those observed by on-chip thermal sensors, which seriously affect the efficiency of DTM. In this paper, a smoothing filter-based Kalman prediction technique is proposed to accurately estimate the temperatures from noisy sensor readings. For the multi-sensor estimation scenario, the spatial correlations among different sensor locations are exploited. On this basis, a multi-sensor synergistic calibration algorithm (known as MSSCA is proposed to improve the simultaneous prediction accuracy of multiple sensors. Moreover, an infrared imaging-based temperature measurement technique is also proposed to capture the thermal traces of an advanced micro devices (AMD quad-core processor in real time. The acquired real temperature data are used to evaluate our prediction performance. Simulation shows that the proposed synergistic calibration scheme can reduce the root-mean-square error (RMSE by 1.2 ∘ C and increase the signal-to-noise ratio (SNR by 15.8 dB (with a very small average runtime overhead compared with assuming the thermal sensor readings to be ideal. Additionally, the average false alarm rate (FAR of the corrected sensor temperature readings can be reduced by 28.6%. These results clearly demonstrate that if our approach is used to perform temperature estimation, the response mechanisms of DTM can be triggered to adjust the voltages, frequencies, and cooling fan speeds at more appropriate times.

  5. On-Line Temperature Estimation for Noisy Thermal Sensors Using a Smoothing Filter-Based Kalman Predictor.

    Science.gov (United States)

    Li, Xin; Ou, Xingtao; Li, Zhi; Wei, Henglu; Zhou, Wei; Duan, Zhemin

    2018-02-02

    Dynamic thermal management (DTM) mechanisms utilize embedded thermal sensors to collect fine-grained temperature information for monitoring the real-time thermal behavior of multi-core processors. However, embedded thermal sensors are very susceptible to a variety of sources of noise, including environmental uncertainty and process variation. This causes the discrepancies between actual temperatures and those observed by on-chip thermal sensors, which seriously affect the efficiency of DTM. In this paper, a smoothing filter-based Kalman prediction technique is proposed to accurately estimate the temperatures from noisy sensor readings. For the multi-sensor estimation scenario, the spatial correlations among different sensor locations are exploited. On this basis, a multi-sensor synergistic calibration algorithm (known as MSSCA) is proposed to improve the simultaneous prediction accuracy of multiple sensors. Moreover, an infrared imaging-based temperature measurement technique is also proposed to capture the thermal traces of an advanced micro devices (AMD) quad-core processor in real time. The acquired real temperature data are used to evaluate our prediction performance. Simulation shows that the proposed synergistic calibration scheme can reduce the root-mean-square error (RMSE) by 1.2 ∘ C and increase the signal-to-noise ratio (SNR) by 15.8 dB (with a very small average runtime overhead) compared with assuming the thermal sensor readings to be ideal. Additionally, the average false alarm rate (FAR) of the corrected sensor temperature readings can be reduced by 28.6%. These results clearly demonstrate that if our approach is used to perform temperature estimation, the response mechanisms of DTM can be triggered to adjust the voltages, frequencies, and cooling fan speeds at more appropriate times.

  6. Fiber Optic Sensors for Temperature Monitoring during Thermal Treatments: An Overview

    Science.gov (United States)

    Schena, Emiliano; Tosi, Daniele; Saccomandi, Paola; Lewis, Elfed; Kim, Taesung

    2016-01-01

    During recent decades, minimally invasive thermal treatments (i.e., Radiofrequency ablation, Laser ablation, Microwave ablation, High Intensity Focused Ultrasound ablation, and Cryo-ablation) have gained widespread recognition in the field of tumor removal. These techniques induce a localized temperature increase or decrease to remove the tumor while the surrounding healthy tissue remains intact. An accurate measurement of tissue temperature may be particularly beneficial to improve treatment outcomes, because it can be used as a clear end-point to achieve complete tumor ablation and minimize recurrence. Among the several thermometric techniques used in this field, fiber optic sensors (FOSs) have several attractive features: high flexibility and small size of both sensor and cabling, allowing insertion of FOSs within deep-seated tissue; metrological characteristics, such as accuracy (better than 1 °C), sensitivity (e.g., 10 pm·°C−1 for Fiber Bragg Gratings), and frequency response (hundreds of kHz), are adequate for this application; immunity to electromagnetic interference allows the use of FOSs during Magnetic Resonance- or Computed Tomography-guided thermal procedures. In this review the current status of the most used FOSs for temperature monitoring during thermal procedure (e.g., fiber Bragg Grating sensors; fluoroptic sensors) is presented, with emphasis placed on their working principles and metrological characteristics. The essential physics of the common ablation techniques are included to explain the advantages of using FOSs during these procedures. PMID:27455273

  7. Fiber Optic Sensors for Temperature Monitoring during Thermal Treatments: An Overview

    Directory of Open Access Journals (Sweden)

    Emiliano Schena

    2016-07-01

    Full Text Available During recent decades, minimally invasive thermal treatments (i.e., Radiofrequency ablation, Laser ablation, Microwave ablation, High Intensity Focused Ultrasound ablation, and Cryo-ablation have gained widespread recognition in the field of tumor removal. These techniques induce a localized temperature increase or decrease to remove the tumor while the surrounding healthy tissue remains intact. An accurate measurement of tissue temperature may be particularly beneficial to improve treatment outcomes, because it can be used as a clear end-point to achieve complete tumor ablation and minimize recurrence. Among the several thermometric techniques used in this field, fiber optic sensors (FOSs have several attractive features: high flexibility and small size of both sensor and cabling, allowing insertion of FOSs within deep-seated tissue; metrological characteristics, such as accuracy (better than 1 °C, sensitivity (e.g., 10 pm·°C−1 for Fiber Bragg Gratings, and frequency response (hundreds of kHz, are adequate for this application; immunity to electromagnetic interference allows the use of FOSs during Magnetic Resonance- or Computed Tomography-guided thermal procedures. In this review the current status of the most used FOSs for temperature monitoring during thermal procedure (e.g., fiber Bragg Grating sensors; fluoroptic sensors is presented, with emphasis placed on their working principles and metrological characteristics. The essential physics of the common ablation techniques are included to explain the advantages of using FOSs during these procedures.

  8. Active Wireless Temperature Sensors for Aerospace Thermal Protection Systems

    Science.gov (United States)

    Milos, Frank S.; Karunaratne, K.; Arnold, Jim (Technical Monitor)

    2002-01-01

    Health diagnostics is an area where major improvements have been identified for potential implementation into the design of new reusable launch vehicles in order to reduce life-cycle costs, to increase safety margins, and to improve mission reliability. NASA Ames is leading the effort to advance inspection and health management technologies for thermal protection systems. This paper summarizes a joint project between NASA Ames and Korteks to develop active wireless sensors that can be embedded in the thermal protection system to monitor sub-surface temperature histories. These devices are thermocouples integrated with radio-frequency identification circuitry to enable acquisition and non-contact communication of temperature data through aerospace thermal protection materials. Two generations of prototype sensors are discussed. The advanced prototype collects data from three type-k thermocouples attached to a 2.54-cm square integrated circuit.

  9. Optical fiber sensors fabricated by the focused ion beam technique

    DEFF Research Database (Denmark)

    Yuan, Scott Wu; Wang, Fei; Bang, Ole

    2012-01-01

    crystal fiber (PCF). Using this technique we fabricate a highly compact fiber-optic Fabry-Pérot (FP) refractive index sensor near the tip of fiber taper, and a highly sensitive in-line temperature sensor in PCF. We also demonstrate the potential of using FIB to selectively fill functional fluid......Focused ion beam (FIB) is a highly versatile technique which helps to enable next generation of lab-on-fiber sensor technologies. In this paper, we demonstrate the use application of FIB to precisely mill the fiber taper and end facet of both conventional single mode fiber (SMF) and photonic...

  10. The Thermal Infrared Sensor onboard NASA's Mars 2020 Mission

    Science.gov (United States)

    Martinez, G.; Perez-Izquierdo, J.; Sebastian, E.; Ramos, M.; Bravo, A.; Mazo, M.; Rodriguez-Manfredi, J. A.

    2017-12-01

    NASA's Mars 2020 rover mission is scheduled for launch in July/August 2020 and will address key questions about the potential for life on Mars. The Mars Environmental Dynamics Analyzer (MEDA) is one of the seven instruments onboard the rover [1] and has been designed to assess the environmental conditions across the rover traverse. MEDA will extend the current record of in-situ meteorological measurements at the surface [2] to other locations on Mars. The Thermal InfraRed Sensor (TIRS) [3] is one of the six sensors comprising MEDA. TIRS will use three downward-looking channels to measure (1) the surface skin temperature (with high heritage from the Rover Environmental Monitoring Station onboard the Mars Science Laboratory mission [4]), (2) the upwelling thermal infrared radiation from the surface and (3) the reflected solar radiation at the surface, and two upward-looking channels to measure the (4) downwelling thermal infrared radiation at the surface and (5) the atmospheric temperature. In combination with other MEDA's sensors, TIRS will allow the quantification of the surface energy budget [5] and the determination of key geophysical properties of the terrain such as the albedo and thermal inertia with an unprecedented spatial resolution. Here we present a general description of the TIRS, with focus on its scientific requirements and results from field campaigns showing the performance of the different channels. References:[1] Rodríguez-Manfredi, J. A. et al. (2014), MEDA: An environmental and meteorological package for Mars 2020, LPSC, 45, 2837. [2] Martínez, G.M. et al. (2017), The Modern Near-Surface Martian Climate: A Review of In-situ Meteorological Data from Viking to Curiosity, Space Science Reviews, 1-44. [3] Pérez-Izquierdo, J. et al. (2017), The Thermal Infrared Sensor (TIRS) of the Mars Environmental Dynamics Analyzer (MEDA) Instrument onboard Mars 2020, IEEE. [4] Sebastián, E. et al. (2010), The Rover Environmental Monitoring Station Ground

  11. Laboratory technique for quantitative thermal emissivity ...

    Indian Academy of Sciences (India)

    Emission of radiation from a sample occurs due to thermal vibration of its .... Quantitative thermal emissivity measurements of geological samples. 393. Figure 1. ...... tral mixture modeling: A new analysis of rock and soil types at the Viking ...

  12. Image acquisition system using on sensor compressed sampling technique

    Science.gov (United States)

    Gupta, Pravir Singh; Choi, Gwan Seong

    2018-01-01

    Advances in CMOS technology have made high-resolution image sensors possible. These image sensors pose significant challenges in terms of the amount of raw data generated, energy efficiency, and frame rate. This paper presents a design methodology for an imaging system and a simplified image sensor pixel design to be used in the system so that the compressed sensing (CS) technique can be implemented easily at the sensor level. This results in significant energy savings as it not only cuts the raw data rate but also reduces transistor count per pixel; decreases pixel size; increases fill factor; simplifies analog-to-digital converter, JPEG encoder, and JPEG decoder design; decreases wiring; and reduces the decoder size by half. Thus, CS has the potential to increase the resolution of image sensors for a given technology and die size while significantly decreasing the power consumption and design complexity. We show that it has potential to reduce power consumption by about 23% to 65%.

  13. Thermal cycling fatigue of organic thermal interface materials using a thermal-displacement measurement technique

    Science.gov (United States)

    Steill, Jason Scott

    The long term reliability of polymer-based thermal interface materials (TIM) is essential for modern electronic packages which require robust thermal management. The challenge for today's materials scientists and engineers is to maximize the heat flow from integrated circuits through a TIM and out the heat sink. Thermal cycling of the electronic package and non-uniformity in the heat flux with respect to the plan area can lead to void formation and delamination which re-introduces inefficient heat transfer. Measurement and understanding at the nano-scale is essential for TIM development. Finding and documenting the evolution of the defects is dependent upon a full understanding of the thermal probes response to changing environmental conditions and the effects of probe usage. The response of the thermal-displacement measurement technique was dominated by changes to the environment. Accurate measurement of the thermal performance was hindered by the inability to create a model system and control the operating conditions. This research highlights the need for continued study into the probe's thermal and mechanical response using tightly controlled test conditions.

  14. Development of Light Powered Sensor Networks for Thermal Comfort Measurement

    Directory of Open Access Journals (Sweden)

    Dasheng Lee

    2008-10-01

    Full Text Available Recent technological advances in wireless communications have enabled easy installation of sensor networks with air conditioning equipment control applications. However, the sensor node power supply, through either power lines or battery power, still presents obstacles to the distribution of the sensing systems. In this study, a novel sensor network, powered by the artificial light, was constructed to achieve wireless power transfer and wireless data communications for thermal comfort measurements. The sensing node integrates an IC-based temperature sensor, a radiation thermometer, a relative humidity sensor, a micro machined flow sensor and a microprocessor for predicting mean vote (PMV calculation. The 935 MHz band RF module was employed for the wireless data communication with a specific protocol based on a special energy beacon enabled mode capable of achieving zero power consumption during the inactive periods of the nodes. A 5W spotlight, with a dual axis tilt platform, can power the distributed nodes over a distance of up to 5 meters. A special algorithm, the maximum entropy method, was developed to estimate the sensing quantity of climate parameters if the communication module did not receive any response from the distributed nodes within a certain time limit. The light-powered sensor networks were able to gather indoor comfort-sensing index levels in good agreement with the comfort-sensing vote (CSV preferred by a human being and the experimental results within the environment suggested that the sensing system could be used in air conditioning systems to implement a comfort-optimal control strategy.

  15. More accurate thermal neutron coincidence counting technique

    International Nuclear Information System (INIS)

    Baron, N.

    1978-01-01

    Using passive thermal neutron coincidence counting techniques, the accuracy of nondestructive assays of fertile material can be improved significantly using a two-ring detector. It was shown how the use of a function of the coincidence count rate ring-ratio can provide a detector response rate that is independent of variations in neutron detection efficiency caused by varying sample moderation. Furthermore, the correction for multiplication caused by SF- and (α,n)-neutrons is shown to be separable into the product of a function of the effective mass of 240 Pu (plutonium correction) and a function of the (α,n) reaction probability (matrix correction). The matrix correction is described by a function of the singles count rate ring-ratio. This correction factor is empirically observed to be identical for any combination of PuO 2 powder and matrix materials SiO 2 and MgO because of the similar relation of the (α,n)-Q value and (α,n)-reaction cross section among these matrix nuclei. However the matrix correction expression is expected to be different for matrix materials such as Na, Al, and/or Li. Nevertheless, it should be recognized that for comparison measurements among samples of similar matrix content, it is expected that some function of the singles count rate ring-ratio can be defined to account for variations in the matrix correction due to differences in the intimacy of mixture among the samples. Furthermore the magnitude of this singles count rate ring-ratio serves to identify the contaminant generating the (α,n)-neutrons. Such information is useful in process control

  16. Distributed cluster management techniques for unattended ground sensor networks

    Science.gov (United States)

    Essawy, Magdi A.; Stelzig, Chad A.; Bevington, James E.; Minor, Sharon

    2005-05-01

    Smart Sensor Networks are becoming important target detection and tracking tools. The challenging problems in such networks include the sensor fusion, data management and communication schemes. This work discusses techniques used to distribute sensor management and multi-target tracking responsibilities across an ad hoc, self-healing cluster of sensor nodes. Although miniaturized computing resources possess the ability to host complex tracking and data fusion algorithms, there still exist inherent bandwidth constraints on the RF channel. Therefore, special attention is placed on the reduction of node-to-node communications within the cluster by minimizing unsolicited messaging, and distributing the sensor fusion and tracking tasks onto local portions of the network. Several challenging problems are addressed in this work including track initialization and conflict resolution, track ownership handling, and communication control optimization. Emphasis is also placed on increasing the overall robustness of the sensor cluster through independent decision capabilities on all sensor nodes. Track initiation is performed using collaborative sensing within a neighborhood of sensor nodes, allowing each node to independently determine if initial track ownership should be assumed. This autonomous track initiation prevents the formation of duplicate tracks while eliminating the need for a central "management" node to assign tracking responsibilities. Track update is performed as an ownership node requests sensor reports from neighboring nodes based on track error covariance and the neighboring nodes geo-positional location. Track ownership is periodically recomputed using propagated track states to determine which sensing node provides the desired coverage characteristics. High fidelity multi-target simulation results are presented, indicating the distribution of sensor management and tracking capabilities to not only reduce communication bandwidth consumption, but to also

  17. Measuring thermal conductivity of polystyrene nanowires using the dual-cantilever technique.

    Science.gov (United States)

    Canetta, Carlo; Guo, Samuel; Narayanaswamy, Arvind

    2014-10-01

    Thermal conductance measurements are performed on individual polystyrene nanowires using a novel measurement technique in which the wires are suspended between two bi-material microcantilever sensors. The nanowires are fabricated via electrospinning process. Thermal conductivity of the nanowire samples is found to be between 6.6 and 14.4 W m(-1) K(-1) depending on sample, a significant increase above typical bulk conductivity values for polystyrene. The high strain rates characteristic of electrospinning are believed to lead to alignment of molecular polymer chains, and hence the increase in thermal conductivity, along the axis of the nanowire.

  18. Whitelists Based Multiple Filtering Techniques in SCADA Sensor Networks

    Directory of Open Access Journals (Sweden)

    DongHo Kang

    2014-01-01

    Full Text Available Internet of Things (IoT consists of several tiny devices connected together to form a collaborative computing environment. Recently IoT technologies begin to merge with supervisory control and data acquisition (SCADA sensor networks to more efficiently gather and analyze real-time data from sensors in industrial environments. But SCADA sensor networks are becoming more and more vulnerable to cyber-attacks due to increased connectivity. To safely adopt IoT technologies in the SCADA environments, it is important to improve the security of SCADA sensor networks. In this paper we propose a multiple filtering technique based on whitelists to detect illegitimate packets. Our proposed system detects the traffic of network and application protocol attacks with a set of whitelists collected from normal traffic.

  19. Untrimmed Low-Power Thermal Sensor for SoC in 22 nm Digital Fabrication Technology

    Directory of Open Access Journals (Sweden)

    Ro'ee Eitan

    2014-12-01

    Full Text Available Thermal sensors (TS are essential for achieving optimized performance and reliability in the era of nanoscale microprocessor and system on chip (SoC. Compiling with the low-power and small die area of the mobile computing, the presented TS supports a wide range of sampling frequencies with an optimized power envelope. The TS supports up to 45 K samples/s, low average power consumption, as low as 20 μW, and small core Si area of 0.013 mm2. Advanced circuit techniques are used in order to overcome process variability, ensuring inaccuracy lower than ±2 °C without any calibration. All this makes the presented thermal sensor a cost-effective, low-power solution for 22 nm nanoscale digital process technology.

  20. Laser Cladding of Embedded Sensors for Thermal Barrier Coating Applications

    Directory of Open Access Journals (Sweden)

    Yanli Zhang

    2018-05-01

    Full Text Available The accurate real-time monitoring of surface or internal temperatures of thermal barrier coatings (TBCs in hostile environments presents significant benefits to the efficient and safe operation of gas turbines. A new method for fabricating high-temperature K-type thermocouple sensors on gas turbine engines using coaxial laser cladding technology has been developed. The deposition of the thermocouple sensors was optimized to provide minimal intrusive features to the TBC, which is beneficial for the operational reliability of the protective coatings. Notably, this avoids a melt pool on the TBC surface. Sensors were deposited onto standard yttria-stabilized zirconia (7–8 wt % YSZ coated substrates; subsequently, they were embedded with second YSZ layers by the Atmospheric Plasma Spray (APS process. Morphology of cladded thermocouples before and after embedding was optimized in terms of topography and internal homogeneity, respectively. The dimensions of the cladded thermocouple were in the order of 200 microns in thickness and width. The thermal and electrical response of the cladded thermocouple was tested before and after embedding in temperatures ranging from ambient to approximately 450 °C in a furnace. Seebeck coefficients of bared and embedded thermocouples were also calculated correspondingly, and the results were compared to that of a commercial standard K-type thermocouple, which demonstrates that laser cladding is a prospective technology for manufacturing microsensors on the surface of or even embedded into functional coatings.

  1. Thermally assisted sensor for conformity assessment of biodiesel production

    International Nuclear Information System (INIS)

    Kawano, M S; Kamikawachi, R C; Fabris, J L; Muller, M

    2015-01-01

    Although biodiesel can be intentionally tampered with, impairing its quality, ineffective production processes may also result in a nonconforming final fuel. For an incomplete transesterification reaction, traces of alcohol (ethanol or methanol) or remaining raw material (vegetable oil or animal fats) may be harmful to consumers, the environment or to engines. Traditional methods for biodiesel assessment are complex, time consuming and expensive, leading to the need for the development of new and more versatile processes for quality control. This work describes a refractometric fibre optic based sensor that is thermally assisted, developed to quantify the remaining methanol or vegetable oil in biodiesel blends. The sensing relies on a long period grating to configure an in-fibre interferometer. A complete analytical routine is demonstrated for the sensor allowing the evaluation of the biodiesel blends without segregation of the components. The results show the sensor can determine the presence of oil or methanol in biodiesel with a concentration ranging from 0% to 10% v/v. The sensor presented a resolution and standard combined uncertainty of 0.013% v/v and 0.62% v/v for biodiesel–oil samples, and 0.007% v/v and 0.22% v/v for biodiesel–methanol samples, respectively. (paper)

  2. Thermally assisted sensor for conformity assessment of biodiesel production

    Science.gov (United States)

    Kawano, M. S.; Kamikawachi, R. C.; Fabris, J. L.; Muller, M.

    2015-02-01

    Although biodiesel can be intentionally tampered with, impairing its quality, ineffective production processes may also result in a nonconforming final fuel. For an incomplete transesterification reaction, traces of alcohol (ethanol or methanol) or remaining raw material (vegetable oil or animal fats) may be harmful to consumers, the environment or to engines. Traditional methods for biodiesel assessment are complex, time consuming and expensive, leading to the need for the development of new and more versatile processes for quality control. This work describes a refractometric fibre optic based sensor that is thermally assisted, developed to quantify the remaining methanol or vegetable oil in biodiesel blends. The sensing relies on a long period grating to configure an in-fibre interferometer. A complete analytical routine is demonstrated for the sensor allowing the evaluation of the biodiesel blends without segregation of the components. The results show the sensor can determine the presence of oil or methanol in biodiesel with a concentration ranging from 0% to 10% v/v. The sensor presented a resolution and standard combined uncertainty of 0.013% v/v and 0.62% v/v for biodiesel-oil samples, and 0.007% v/v and 0.22% v/v for biodiesel-methanol samples, respectively.

  3. Outlier Detection Techniques For Wireless Sensor Networks: A Survey

    NARCIS (Netherlands)

    Zhang, Y.; Meratnia, Nirvana; Havinga, Paul J.M.

    2008-01-01

    In the field of wireless sensor networks, measurements that significantly deviate from the normal pattern of sensed data are considered as outliers. The potential sources of outliers include noise and errors, events, and malicious attacks on the network. Traditional outlier detection techniques are

  4. Characteristics of Laser Flash Technique for Thermal Diffusivity Measurement

    Energy Technology Data Exchange (ETDEWEB)

    Park, D. G.; Kim, H. M.; Hong, G. P

    2008-08-15

    In relation to selection of thermal conductivity measurement technology, various thermal conductivity measurement technique are investigated for characteristics of each technique and it's measurable range. For the related laser flash techniques, various technical characteristics are reviewed and discussed. Especially, Parker adiabatic model are reviewed because of importance for basic theory of the thermal diffusivity determination. Finite pulse time effect, heat loss effect and non-uniform heating effect, which are main technical factors for laser flash technique, are considered. Finally, characteristics of constituent elements for laser flash measurement system are reviewed and investigated in detail.

  5. Operation of transition-edge sensors with excess thermal noise

    International Nuclear Information System (INIS)

    Maasilta, I J; Kinnunen, K M; Nuottajaervi, A K; Leppaeniemi, J; Luukanen, A

    2006-01-01

    The superconducting transition-edge sensor (TES) is currently one of the most attractive choices for ultra-high resolution calorimetry in the keV x-ray band, and is being considered for future ESA and NASA missions. We have performed a study on the noise characteristics of Au/Ti bilayer TESs, at operating temperatures around ∼100 mK, with the SQUID readout at 1.5 K. Experimental results indicate that without modifications the back-action noise from the SQUID chip degrades the noise characteristics significantly. We present a simple and effective solution to the problem: by installing an extra shunt resistor which absorbs the excess radiation from the SQUID input, we have reduced the excess thermal (photon) noise power down by approximately a factor of five, allowing high resolution operation of the sensors

  6. Development of a micro liquid-level sensor for harsh environments using a periodic heating technique

    International Nuclear Information System (INIS)

    Hong, Jonggan; Kim, Dongsik; Chang, Young Soo

    2010-01-01

    This paper describes the development and testing of a novel micro thermal sensor for point sensing of lubrication oil level in industrial compressors. The results reported in this work can be applied to various harsh environments that feature high temperature/pressure, limited space and flow/vibration. The sensor employs an ac (alternating current) thermal technique with a single heating/sensing element. As the sensing scheme is based on the so-called three-omega method, the sensing signal is noise-resistant and hardly affected by flow in the liquid being measured. Experiments with DI water, ethanol and ethylene glycol confirm that the sensor performance is satisfactory under atmospheric pressure. Also, to mimic harsh conditions as in an industrial compressor, tests are performed in a pressure vessel containing R410A gas and polyvinylether lubrication oil under high temperatures and pressures. The results indicate that the sensitivity and response time of the developed sensor are appropriate for practical usage in harsh environments. As the sensor can be easily mass-produced at low cost using photolithography, it has strong potential for industrial applications

  7. Transient plane source (tps) sensors for simultaneous measurements of thermal conductivity and thermal diffusivity of insulators, fluids and conductors

    Science.gov (United States)

    Maqsood, Asghari; Anis-ur-Rehman, M.

    2013-12-01

    Thermal conductivity and thermal diffusivity are two important physical properties for designing any food engineering processes1. The knowledge of thermal properties of the elements, compounds and different materials in many industrial applications is a requirement for their final functionality. Transient plane source (tps) sensors are reported2 to be useful for the simultaneous measurement of thermal conductivity, thermal diffusivity and volumetric heat capacity of insulators, conductor liquids3 and high-TC superconductors4. The tps-sensor consists of a resistive element in the shape of double spiral made of 10 micrometer thick Ni-foils covered on both sides with 25 micrometer thick Kapton. This sensor acts both as a heat source and a resistance thermometer for recording the time dependent temperature increase. From the knowledge of the temperature co-efficient of the metal spiral, the temperature increase of the sensor can be determined precisely by placing the sensor in between two surfaces of the same material under test. This temperature increase is then related to the thermal conductivity, thermal diffusivity and volumetric heat capacity by simple relations2,5. The tps-sensor has been used to measure thermal conductivities from 0.001 Wm-1K-1to 600 Wm-1K-1 and temperature ranges covered from 77K- 1000K. This talk gives the design, advantages and limitations of the tpl-sensor along with its applications to the measurementof thermal properties in a variety of materials.

  8. Transient plane source (tps) sensors for simultaneous measurements of thermal conductivity and thermal diffusivity of insulators, fluids and conductors

    International Nuclear Information System (INIS)

    Maqsood, Asghari; Anis-ur-Rehman, M

    2013-01-01

    Thermal conductivity and thermal diffusivity are two important physical properties for designing any food engineering processes 1 . The knowledge of thermal properties of the elements, compounds and different materials in many industrial applications is a requirement for their final functionality. Transient plane source (tps) sensors are reported 2 to be useful for the simultaneous measurement of thermal conductivity, thermal diffusivity and volumetric heat capacity of insulators, conductor liquids 3 and high-T C superconductors 4 . The tps-sensor consists of a resistive element in the shape of double spiral made of 10 micrometer thick Ni-foils covered on both sides with 25 micrometer thick Kapton. This sensor acts both as a heat source and a resistance thermometer for recording the time dependent temperature increase. From the knowledge of the temperature co-efficient of the metal spiral, the temperature increase of the sensor can be determined precisely by placing the sensor in between two surfaces of the same material under test. This temperature increase is then related to the thermal conductivity, thermal diffusivity and volumetric heat capacity by simple relations 2,5 . The tps-sensor has been used to measure thermal conductivities from 0.001 Wm −1 K −1 to 600 Wm −1 K −1 and temperature ranges covered from 77K– 1000K. This talk gives the design, advantages and limitations of the tpl-sensor along with its applications to the measurementof thermal properties in a variety of materials

  9. Study of thermal - hydraulic sensors signal fluctuations in PWR

    International Nuclear Information System (INIS)

    Hennion, F.

    1987-10-01

    This thesis deals with signal fluctuations of thermal-hydraulic sensors in the main coolant primary of a pressurized water reactor. The aim of this work is to give a first response about the potentiality of use of these noise signals for the functionning monitoring. Two aspects have been studied: - the modelisation of temperature fluctuations of core thermocouples, by a Monte-Carlo method, gives the main characteristics of these signals and their domain of application. - the determination of eigenfrequency in the primary by an acoustic representation could permit the monitoring of local and global thermo-hydraulic conditions [fr

  10. Thermal diffusivity of diamond films using a laser pulse technique

    International Nuclear Information System (INIS)

    Albin, S.; Winfree, W.P.; Crews, B.S.

    1990-01-01

    Polycrystalline diamond films were deposited using a microwave plasma-enhanced chemical vapor deposition process. A laser pulse technique was developed to measure the thermal diffusivity of diamond films deposited on a silicon substrate. The effective thermal diffusivity of a diamond film on silicon was measured by observing the phase and amplitude of the cyclic thermal waves generated by laser pulses. An analytical model is presented to calculate the effective inplane (face-parallel) diffusivity of a two-layer system. The model is used to reduce the effective thermal diffusivity of the diamond/silicon sample to a value for the thermal diffusivity and conductivity of the diamond film

  11. Sap flow is Underestimated by Thermal Dissipation Sensors due to Alterations of Wood Anatomy

    Science.gov (United States)

    Marañón-Jiménez, S.; Wiedemann, A.; van den Bulcke, J.; Cuntz, M.; Rebmann, C.; Steppe, K.

    2014-12-01

    The thermal dissipation technique (TD) is one of the most commonly adopted methods for sap flow measurements. However, underestimations of up to 60% of the tree transpiration have been reported with this technique, although the causes are not certainly known. The insertion of TD sensors within the stems causes damage of the wood tissue and subsequent healing reactions, changing wood anatomy and likely the sap flow path. However, the anatomical changes in response to the insertion of sap flow sensors and the effects on the measured flow have not been assessed yet. In this study, we investigate the alteration of vessel anatomy on wounds formed around TD sensors. Our main objectives were to elucidate the anatomical causes of sap flow underestimation for ring-porous and diffuse-porous species, and relate these changes to sap flow underestimations. Successive sets of TD probes were installed in early, mid and end of the growing season in Fagus sylvatica (diffuse-porous) and Quercus petraea (ring-porous) trees. They were logged after the growing season and additional sets of sensors were installed in the logged stems with presumably no healing reaction. The wood tissue surrounding each sensor was then excised and analysed by X-ray computed microtomography (X-ray micro CT). This technique allowed the quantification of vessel anatomical characteristics and the reconstruction of the 3-D internal microstructure of the xylem vessels so that extension and shape of the altered area could be determined. Gels and tyloses clogged the conductive vessels around the sensors in both beech and oak. The extension of the affected area was larger for beech although these anatomical changes led to similar sap flow underestimations in both species. The higher vessel size in oak may explain this result and, therefore, larger sap flow underestimation per area of affected conductive tissue. The wound healing reaction likely occurred within the first weeks after sensor installation, which

  12. Low Thermal Conductance Transition Edge Sensor (TES) for SPICA

    International Nuclear Information System (INIS)

    Khosropanah, P.; Dirks, B.; Kuur, J. van der; Ridder, M.; Bruijn, M.; Popescu, M.; Hoevers, H.; Gao, J. R.; Morozov, D.; Mauskopf, P.

    2009-01-01

    We fabricated and characterized low thermal conductance transition edge sensors (TES) for SAFARI instrument on SPICA. The device is based on a superconducting Ti/Au bilayer deposited on suspended SiN membrane. The critical temperature of the device is 113 mK. The low thermal conductance is realized by using long and narrow SiN supporting legs. All measurements were performed having the device in a light-tight box, which to a great extent eliminates the loading of the background radiation. We measured the current-voltage (IV) characteristics of the device in different bath temperatures and determine the thermal conductance (G) to be equal to 320 fW/K. This value corresponds to a noise equivalent power (NEP) of 3x10 -19 W/√(Hz). The current noise and complex impedance is also measured at different bias points at 55 mK bath temperature. The measured electrical (dark) NEP is 1x10 -18 W/√(Hz), which is about a factor of 3 higher than what we expect from the thermal conductance that comes out of the IV curves. Despite using a light-tight box, the photon noise might still be the source of this excess noise. We also measured the complex impedance of the same device at several bias points. Fitting a simple first order thermal-electrical model to the measured data, we find an effective time constant of about 2.7 ms and a thermal capacity of 13 fJ/K in the middle of the transition.

  13. Pyrometer model based on sensor physical structure and thermal operation

    International Nuclear Information System (INIS)

    Sebastian, Eduardo; Armiens, Carlos; Gomez-Elvira, Javier

    2010-01-01

    This paper proposes a new simplified thermal model for pyrometers, which takes into account both their internal and external physical structure and operation. The model is experimentally tested on the REMS GTS, an instrument for measuring ground temperature, which is part of the payload of the NASA MSL mission to Mars. The proposed model is based on an energy balance equation that represents the heat fluxes exchanged between sensor elements through radiation, conduction and convection. Despite being mathematically more complex than the more commonly used model, the proposed model makes it possible to design a methodology to compensate the effects of sensor spatial thermal gradients. The paper includes a practical methodology for identifying model constants, which is part of the GTS instrument calibration plan and uses a differential approach to avoid setup errors. Experimental results of the model identification methodology and a target temperature measurement performance after identification has been made are reported. Results demonstrate the good behaviour of the model, with errors below 0.15 deg. C in target temperature estimates.

  14. Microwave Readout Techniques for Very Large Arrays of Nuclear Sensors

    Energy Technology Data Exchange (ETDEWEB)

    Ullom, Joel [Univ. of Colorado, Boulder, CO (United States). Dept. of Physics

    2017-05-17

    During this project, we transformed the use of microwave readout techniques for nuclear sensors from a speculative idea to reality. The core of the project consisted of the development of a set of microwave electronics able to generate and process large numbers of microwave tones. The tones can be used to probe a circuit containing a series of electrical resonances whose frequency locations and widths depend on the state of a network of sensors, with one sensor per resonance. The amplitude and phase of the tones emerging from the circuit are processed by the same electronics and are reduced to the sensor signals after two demodulation steps. This approach allows a large number of sensors to be interrogated using a single pair of coaxial cables. We successfully developed hardware, firmware, and software to complete a scalable implementation of these microwave control electronics and demonstrated their use in two areas. First, we showed that the electronics can be used at room temperature to read out a network of diverse sensor types relevant to safeguards or process monitoring. Second, we showed that the electronics can be used to measure large numbers of ultrasensitive cryogenic sensors such as gamma-ray microcalorimeters. In particular, we demonstrated the undegraded readout of up to 128 channels and established a path to even higher multiplexing factors. These results have transformed the prospects for gamma-ray spectrometers based on cryogenic microcalorimeter arrays by enabling spectrometers whose collecting areas and count rates can be competitive with high purity germanium but with 10x better spectral resolution.

  15. Diagnosis of Thermal Efficiency of Nuclear Power Plants Using Optical Torque Sensors

    International Nuclear Information System (INIS)

    Shuichi Umezawa; Jun Adachi

    2006-01-01

    A new optical torque measuring method was applied to diagnosis of thermal efficiency of nuclear power plants. The sensor allows torque deformation of the rotor caused by power transmission to be measured without contact. Semiconductor laser beams and small pieces of stainless reflector that have bar-code patterns are employed. The intensity of the reflected laser beam is measured and then input into a computer through an APD and an A/D converter having high frequency sampling rates. The correlation analysis technique can translate these data into the torque deformation angle. This angle allows us to obtain the turbine output along with the torsional rigidity and the rotating speed of the rotor. The sensor was applied to a nuclear plant of Tokyo Electric Power Company, TEPCO, following its application success to the early combined cycle plants and the advanced combined cycle plants of TEPCO. As the turbine rotor of the nuclear power plant is less exposed than that of the combined cycle plants, the measurement position is confined to a narrow gap. In order to overcome the difficulty in installation, the shape of the sensor is modified to be long and thin. Sensor performance of the nuclear power plant was inspected over a year. The value of the torsional rigidity was analyzed by the finite element method at first. Accuracy was improved by correcting the torsional rigidity so that the value was consistent with the generator output. As a result, it is considered that the sensor performance has reached a practical use level. (authors)

  16. Ultra-miniature wireless temperature sensor for thermal medicine applications.

    Science.gov (United States)

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

    2011-01-01

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

  17. Segmentation techniques for extracting humans from thermal images

    CSIR Research Space (South Africa)

    Dickens, JS

    2011-11-01

    Full Text Available A pedestrian detection system for underground mine vehicles is being developed that requires the segmentation of people from thermal images in underground mine tunnels. A number of thresholding techniques are outlined and their performance on a...

  18. Metallographic techniques for evaluation of thermal barrier coatings

    Science.gov (United States)

    Brindley, William J.; Leonhardt, Todd A.

    1990-01-01

    The performance of ceramic thermal barrier coatings is strongly dependent on the amount and shape of the porosity in the coating. Current metallographic techniques do not provide polished surfaces that are adequate for a repeatable interpretation of the coating structures. A technique recently developed at NASA-Lewis for preparation of thermal barrier coating sections combines epoxy impregnation, careful sectioning and polishing, and interference layering to provide previously unobtainable information on processing-induced porosity. In fact, increased contrast and less ambiguous structure developed by the method make automatic quantitative metallography a viable option for characterizing thermal barrier coating structures.

  19. Thermal Characterization of Edible Oils by Using Photopyroelectric Technique

    Science.gov (United States)

    Lara-Hernández, G.; Suaste-Gómez, E.; Cruz-Orea, A.; Mendoza-Alvarez, J. G.; Sánchez-Sinéncio, F.; Valcárcel, J. P.; García-Quiroz, A.

    2013-05-01

    Thermal properties of several edible oils such as olive, sesame, and grape seed oils were obtained by using the photopyroelectric technique. The inverse photopyroelectric configuration was used in order to obtain the thermal effusivity of the oil samples. The theoretical equation for the photopyroelectric signal in this configuration, as a function of the incident light modulation frequency, was fitted to the experimental data in order to obtain the thermal effusivity of these samples. Also, the back photopyroelectric configuration was used to obtain the thermal diffusivity of these oils; this thermal parameter was obtained by fitting the theoretical equation for this configuration, as a function of the sample thickness (called the thermal wave resonator cavity), to the experimental data. All measurements were done at room temperature. A complete thermal characterization of these edible oils was achieved by the relationship between the obtained thermal diffusivities and thermal effusivities with their thermal conductivities and volumetric heat capacities. The obtained results are in agreement with the thermal properties reported for the case of the olive oil.

  20. Tailoring properties of lossy-mode resonance optical fiber sensors with atomic layer deposition technique

    Science.gov (United States)

    Kosiel, Kamil; Koba, Marcin; Masiewicz, Marcin; Śmietana, Mateusz

    2018-06-01

    The paper shows application of atomic layer deposition (ALD) technique as a tool for tailoring sensorial properties of lossy-mode-resonance (LMR)-based optical fiber sensors. Hafnium dioxide (HfO2), zirconium dioxide (ZrO2), and tantalum oxide (TaxOy), as high-refractive-index dielectrics that are particularly convenient for LMR-sensor fabrication, were deposited by low-temperature (100 °C) ALD ensuring safe conditions for thermally vulnerable fibers. Applicability of HfO2 and ZrO2 overlays, deposited with ALD-related atomic level thickness accuracy for fabrication of LMR-sensors with controlled sensorial properties was presented. Additionally, for the first time according to our best knowledge, the double-layer overlay composed of two different materials - silicon nitride (SixNy) and TaxOy - is presented for the LMR fiber sensors. The thin films of such overlay were deposited by two different techniques - PECVD (the SixNy) and ALD (the TaxOy). Such approach ensures fast overlay fabrication and at the same time facility for resonant wavelength tuning, yielding devices with satisfactory sensorial properties.

  1. A micro dew point sensor with a thermal detection principle

    Science.gov (United States)

    Kunze, M.; Merz, J.; Hummel, W.-J.; Glosch, H.; Messner, S.; Zengerle, R.

    2012-01-01

    We present a dew point temperature sensor with the thermal detection of condensed water on a thin membrane, fabricated by silicon micromachining. The membrane (600 × 600 × ~1 µm3) is part of a silicon chip and contains a heating element as well as a thermopile for temperature measurement. By dynamically heating the membrane and simultaneously analyzing the transient increase of its temperature it is detected whether condensed water is on the membrane or not. To cool the membrane down, a peltier cooler is used and electronically controlled in a way that the temperature of the membrane is constantly held at a value where condensation of water begins. This temperature is measured and output as dew point temperature. The sensor system works in a wide range of dew point temperatures between 1 K and down to 44 K below air temperature. In experimental investigations it could be proven that the deviation of the measured dew point temperatures compared to reference values is below ±0.2 K in an air temperature range of 22 to 70 °C. At low dew point temperatures of -20 °C (air temperature = 22 °C) the deviation increases to nearly -1 K.

  2. A micro dew point sensor with a thermal detection principle

    International Nuclear Information System (INIS)

    Kunze, M; Merz, J; Glosch, H; Messner, S; Zengerle, R; Hummel, W-J

    2012-01-01

    We present a dew point temperature sensor with the thermal detection of condensed water on a thin membrane, fabricated by silicon micromachining. The membrane (600 × 600 × ∼1 µm 3 ) is part of a silicon chip and contains a heating element as well as a thermopile for temperature measurement. By dynamically heating the membrane and simultaneously analyzing the transient increase of its temperature it is detected whether condensed water is on the membrane or not. To cool the membrane down, a peltier cooler is used and electronically controlled in a way that the temperature of the membrane is constantly held at a value where condensation of water begins. This temperature is measured and output as dew point temperature. The sensor system works in a wide range of dew point temperatures between 1 K and down to 44 K below air temperature. In experimental investigations it could be proven that the deviation of the measured dew point temperatures compared to reference values is below ±0.2 K in an air temperature range of 22 to 70 °C. At low dew point temperatures of −20 °C (air temperature = 22 °C) the deviation increases to nearly −1 K

  3. Manufacturing of thermal neutron sensor using pMOS

    International Nuclear Information System (INIS)

    Lee, Nam Ho; Kim, Seung Ho

    2005-05-01

    A pMOSFET sensor having a Gadolinium converter has been invented successfully as a slow neutron sensor that is sensitive to neutron energy down to 0.025 eV. The Gd layer converts low energy neutrons to ionizing radiation of which the amount is proportional to neutron dose. Ionising radiation from neutron reactions changes the charge state of the gate oxide of the pMOSFET. The Gd-pMOSFETs were tested at a neutron beam port of HANARO research reactor and a 60 CO irradiation facility to investigate slow neutron response and gamma response, respectively. The voltage change was proportional to the accumulated slow neutron dose. The results from Gd coupled MOSFET neutron dosemeters shows an excellent sensitivity (15 - 16mV/cGy) and linearity to thermal neutrons with negligible background contamination. The results demonstrate the outstanding performance of the Gd coupled MOSFET neutron dosemeters clearly. The Gd-pMOSFET can also be used in a mixed radiation field by subtracting the voltage change of a pMOSFET without Gd from that of the Gd-pMOSFET

  4. High accuracy thermal conductivity measurement of aqueous cryoprotective agents and semi-rigid biological tissues using a microfabricated thermal sensor

    Science.gov (United States)

    Liang, Xin M.; Sekar, Praveen K.; Zhao, Gang; Zhou, Xiaoming; Shu, Zhiquan; Huang, Zhongping; Ding, Weiping; Zhang, Qingchuan; Gao, Dayong

    2015-01-01

    An improved thermal-needle approach for accurate and fast measurement of thermal conductivity of aqueous and soft biomaterials was developed using microfabricated thermal conductivity sensors. This microscopic measuring device was comprehensively characterized at temperatures from 0 °C to 40 °C. Despite the previous belief, system calibration constant was observed to be highly temperature-dependent. Dynamic thermal conductivity response during cooling (40 °C to –40 °C) was observed using the miniaturized single tip sensor for various concentrations of CPAs, i.e., glycerol, ethylene glycol and dimethyl sulfoxide. Chicken breast, chicken skin, porcine limb, and bovine liver were assayed to investigate the effect of anatomical heterogeneity on thermal conductivity using the arrayed multi-tip sensor at 20 °C. Experimental results revealed distinctive differences in localized thermal conductivity, which suggests the use of approximated or constant property values is expected to bring about results with largely inflated uncertainties when investigating bio-heat transfer mechanisms and/or performing sophisticated thermal modeling with complex biological tissues. Overall, the presented micro thermal sensor with automated data analysis algorithm is a promising approach for direct thermal conductivity measurement of aqueous solutions and soft biomaterials and is of great value to cryopreservation of tissues, hyperthermia or cryogenic, and other thermal-based clinical diagnostics and treatments. PMID:25993037

  5. Analysis of Piezoelectric Structural Sensors with Emergent Computing Techniques

    Science.gov (United States)

    Ramers, Douglas L.

    2005-01-01

    pressurizing the bottle on a test stand, and running sweeps of excitations frequencies for each of the piezo sensors and recording the resulting impedance. The sweeps were limited to 401 points by the available analyzer, and it was decided to perform individual sweeps at five different excitation frequency ranges. The frequency ranges used for the PZTs were different in two of the five ranges from the ranges used for the SCP. The bottles were pressurized to empty (no water), 0psig, 77 psig, 155 psig, 227 psig in nearly uniform increments of about 77psi. One of each of the two types of piezo sensors was fastened on to the bottle surface at two locations: about midway between the ends on cylindrical portion of the bottle and at the very edge of one of the end domes. The data was collected in files by sensor type (2 cases), by location (2 cases), by frequency range (5 cases), and pressure (5cases) to produce 100 data sets of 401 impedances. After familiarization with the piezo sensing technology and obtaining the data, the team developed a set of questions to try to answer regarding the data and made assignments of responsibilities. The next section lists the questions, and the remainder of the report describes the data analysis work performed by Dr. Ramers. This includes a discussion of the data, the approach to answering the question using statistical techniques, the use of an emergent system to investigate the data where statistical techniques were not usable, conclusions regarding the data, and recommendations.

  6. A thermal sensor for water using self-heated NTC thick-film segmented thermistors

    OpenAIRE

    Nikolić, Maria Vesna; Radojčić, B. M.; Aleksić, Obrad; Luković, Miloljub D.; Nikolić, Pantelija

    2011-01-01

    A simple thermal (heat loss) sensor system was designed in a small plastic tube housing using a negative thermal coefficient (NTC) thick-film thermistor as a self-heating sensor. The voltage power supply [range constant voltage (RCV)-range constant voltage] uses the measured input water temperature to select the applied voltage in steps (up and down) in order to enable operation of the sensor at optimal sensitivity for different water temperatures. The input water temperature was measured usi...

  7. Bonding techniques for hybrid active pixel sensors (HAPS)

    Energy Technology Data Exchange (ETDEWEB)

    Bigas, M. [Centre Nacional de Microelectronica, CNM-IMB (CSIC), Campus Universitat Autonoma de Barcelona, 08193 Bellaterra, Barcelona (Spain)]. E-mail: Marc.Bigas@cnm.es; Cabruja, E. [Centre Nacional de Microelectronica, CNM-IMB (CSIC), Campus Universitat Autonoma de Barcelona, 08193 Bellaterra, Barcelona (Spain)]. E-mail: Enric.Cabruja@cnm.es; Lozano, M. [Centre Nacional de Microelectronica, CNM-IMB (CSIC), Campus Universitat Autonoma de Barcelona, 08193 Bellaterra, Barcelona (Spain)

    2007-05-01

    A hybrid active pixel sensor (HAPS) consists of an array of sensing elements which is connected to an electronic read-out unit. The most used way to connect these two different devices is bump bonding. This interconnection technique is very suitable for these systems because it allows a very fine pitch and a high number of I/Os. However, there are other interconnection techniques available such as direct bonding. This paper, as a continuation of a review [M. Lozano, E. Cabruja, A. Collado, J. Santander, M. Ullan, Nucl. Instr. and Meth. A 473 (1-2) (2001) 95-101] published in 2001, presents an update of the different advanced bonding techniques available for manufacturing a hybrid active pixel detector.

  8. Development of a micro-thermal flow sensor with thin-film thermocouples

    Science.gov (United States)

    Kim, Tae Hoon; Kim, Sung Jin

    2006-11-01

    A micro-thermal flow sensor is developed using thin-film thermocouples as temperature sensors. A micro-thermal flow sensor consists of a heater and thin-film thermocouples which are deposited on a quartz wafer using stainless steel masks. Thin-film thermocouples are made of standard K-type thermocouple materials. The mass flow rate is measured by detecting the temperature difference of the thin-film thermocouples located in the upstream and downstream sections relative to a heater. The performance of the micro-thermal flow sensor is experimentally evaluated. In addition, a numerical model is presented and verified by experimental results. The effects of mass flow rate, input power, and position of temperature sensors on the performance of the micro-thermal flow sensor are experimentally investigated. At low values, the mass flow rate varies linearly with the temperature difference. The linearity of the micro-thermal flow sensor is shown to be independent of the input power. Finally, the position of the temperature sensors is shown to affect both the sensitivity and the linearity of the micro-thermal flow sensor.

  9. Monitoring volcanic thermal activity by Robust Satellite Techniques: achievements and perspectives

    Science.gov (United States)

    Tramutoli, V.; Marchese, F.; Mazzeo, G.; Pergola, N.

    2009-12-01

    Satellite data have been increasingly used in last decades to study active volcanoes and to monitor thermal activity variation in space-time domain. Several satellite techniques and original methods have been developed and tested, devoted to hotspot detection and thermal monitoring. Among them, a multi-temporal approach, named RST (Robust Satellite Techniques), has shown high performances in detecting hotspots, with a low false positive rate under different observational and atmospheric conditions, providing also a potential toward low-level thermal anomalies which may announce incoming eruptions. As the RST scheme is intrinsically exportable on different geographic areas and satellite sensors, it has been applied and tested on a number of volcanoes and in different environmental conditions. This work presents major results and outcomes of studies carried out on Etna and Stromboli (Italy), Merapi (Java Indonesia), Asamayama (Japan), Jebel Al Tair (Yemen) by using different satellite systems and sensors (e.g. NOAA-AVHRR, EOS-MODIS, MSG-SEVIRI). Performances on hotspot detection, early warning and real-time monitoring, together with capabilities in possible thermal precursor identification, will be presented and discussed.

  10. Differential sensor in front photopyroelectric technique: II. Experimental

    International Nuclear Information System (INIS)

    Ivanov, R; Moreno, I; Araujo-Andrade, C; MarIn, E; Cruz-Orea, A; Pichardo-Molina, J L

    2009-01-01

    We describe the differential cell design and the experimental (optical and electronic) setup for the differential front photopyroelectric technique, whose theory has been developed in the first part of this paper (Ivanov et al 2008 J. Phys. D: Appl. Phys. 41 085106). We will show first how the direct (non-differential) front photopyroelectric theory described in our previous paper reproduces well the experimental results. The usefulness of the differential technique is demonstrated by means of experimental measurements of the thermal effusivity in binary ethanol-water and glycerol-water mixtures, based on a theoretical methodology that simplifies the measurement procedure and diminishes the experimental uncertainty.

  11. Differential sensor in front photopyroelectric technique: II. Experimental

    Energy Technology Data Exchange (ETDEWEB)

    Ivanov, R; Moreno, I; Araujo-Andrade, C [Facultad de Fisica, Universidad Autonoma de Zacatecas, Calz. Solidaridad Esquina Paseo de la Bufa s/n, CP 98060, Zacatecas, Zac. (Mexico); MarIn, E [Centro de Investigacion en Ciencia Aplicada y TecnologIa Avanzada-Instituto Politecnico Nacional, Legaria 694, Col. Irrigacion, CP 11500, Mexico D.F. (Mexico); Cruz-Orea, A [Departamento de Fisica, CINVESTAV-IPN, Av. IPN No. 2508, Col. San Pedro Zacatenco, CP 07360, Mexico D.F. (Mexico); Pichardo-Molina, J L, E-mail: rumen@fisica.uaz.edu.m [Centro de Investigaciones en Optica, Loma del Bosque 115, Loma del Campestre, CP 37150, Leon, Guanajuato (Mexico)

    2009-06-21

    We describe the differential cell design and the experimental (optical and electronic) setup for the differential front photopyroelectric technique, whose theory has been developed in the first part of this paper (Ivanov et al 2008 J. Phys. D: Appl. Phys. 41 085106). We will show first how the direct (non-differential) front photopyroelectric theory described in our previous paper reproduces well the experimental results. The usefulness of the differential technique is demonstrated by means of experimental measurements of the thermal effusivity in binary ethanol-water and glycerol-water mixtures, based on a theoretical methodology that simplifies the measurement procedure and diminishes the experimental uncertainty.

  12. Thermal Stability of Magnetic Compass Sensor for High Accuracy Positioning Applications

    OpenAIRE

    Van-Tang PHAM; Dinh-Chinh NGUYEN; Quang-Huy TRAN; Duc-Trinh CHU; Duc-Tan TRAN

    2015-01-01

    Using magnetic compass sensors in angle measurements have a wide area of application such as positioning, robot, landslide, etc. However, one of the most phenomenal that affects to the accuracy of the magnetic compass sensor is the temperature. This paper presents two thermal stability schemes for improving performance of a magnetic compass sensor. The first scheme uses the feedforward structure to adjust the angle output of the compass sensor adapt to the variation of the temperature. The se...

  13. Analytical tools for thermal infrared engineerig: a thermal sensor simulation package

    Science.gov (United States)

    Jaggi, Sandeep

    1992-09-01

    The Advanced Sensor Development Laboratory (ASDL) at the Stennis Space Center develops, maintains and calibrates remote sensing instruments for the National Aeronautics & Space Administration. To perform system design trade-offs, analysis, and establish system parameters, ASDL has developed a software package for analytical simulation of sensor systems. This package called 'Analytical Tools for Thermal InfraRed Engineering'--ATTIRE, simulates the various components of a sensor system. The software allows each subsystem of the sensor to be analyzed independently for its performance. These performance parameters are then integrated to obtain system level information such as SNR, NER, NETD etc. This paper describes the uses of the package and the physics that were used to derive the performance parameters. In addition, ATTIRE can be used as a tutorial for understanding the distribution of thermal flux or solar irradiance over selected bandwidths of the spectrum. This spectrally distributed incident flux can then be analyzed as it propagates through the subsystems that constitute the entire sensor. ATTIRE provides a variety of functions ranging from plotting black-body curves for varying bandwidths and computing the integral flux, to performing transfer function analysis of the sensor system. The package runs from a menu- driven interface in a PC-DOS environment. Each sub-system of the sensor is represented by windows and icons. A user-friendly mouse-controlled point-and-click interface allows the user to simulate various aspects of a sensor. The package can simulate a theoretical sensor system. Trade-off studies can be easily done by changing the appropriate parameters and monitoring the effect of the system performance. The package can provide plots of system performance versus any system parameter. A parameter (such as the entrance aperture of the optics) could be varied and its effect on another parameter (e.g., NETD) can be plotted. A third parameter (e.g., the

  14. Automated thermal mapping techniques using chromatic image analysis

    Science.gov (United States)

    Buck, Gregory M.

    1989-01-01

    Thermal imaging techniques are introduced using a chromatic image analysis system and temperature sensitive coatings. These techniques are used for thermal mapping and surface heat transfer measurements on aerothermodynamic test models in hypersonic wind tunnels. Measurements are made on complex vehicle configurations in a timely manner and at minimal expense. The image analysis system uses separate wavelength filtered images to analyze surface spectral intensity data. The system was initially developed for quantitative surface temperature mapping using two-color thermographic phosphors but was found useful in interpreting phase change paint and liquid crystal data as well.

  15. Distributed perfluorinated POF strain sensor using OTDR and OFDR techniques

    Science.gov (United States)

    Liehr, Sascha; Wendt, Mario; Krebber, Katerina

    2009-10-01

    This paper presents the latest advances in distributed strain sensing using perfluorinated (PF) polymer optical fibers (POF). Compared to previously introduced PMMA POF strain sensors, PF POF have the advantage of lower loss and therefore extended measurement length of more than 500 m at increased spatial resolution of 10 cm. It is shown that PF POF can measure strain distributed up to 100 %. The characteristic backscatter signature of this fiber type provides additional evaluation possibilities. We show that, by applying a cross-correlation algorithm to the backscatter signal, the distributed length change can be measured along the fiber. We also present, to our knowledge for the first time, incoherent Optical Frequency Domain Reflectometry (OFDR) in POF to measure distributed reflections and loss along the fiber. The OFDR technique proves superior to existing OTDR techniques in measurement speed, resolution and potential instrument costs.

  16. Optimization of DNA Sensor Model Based Nanostructured Graphene Using Particle Swarm Optimization Technique

    Directory of Open Access Journals (Sweden)

    Hediyeh Karimi

    2013-01-01

    Full Text Available It has been predicted that the nanomaterials of graphene will be among the candidate materials for postsilicon electronics due to their astonishing properties such as high carrier mobility, thermal conductivity, and biocompatibility. Graphene is a semimetal zero gap nanomaterial with demonstrated ability to be employed as an excellent candidate for DNA sensing. Graphene-based DNA sensors have been used to detect the DNA adsorption to examine a DNA concentration in an analyte solution. In particular, there is an essential need for developing the cost-effective DNA sensors holding the fact that it is suitable for the diagnosis of genetic or pathogenic diseases. In this paper, particle swarm optimization technique is employed to optimize the analytical model of a graphene-based DNA sensor which is used for electrical detection of DNA molecules. The results are reported for 5 different concentrations, covering a range from 0.01 nM to 500 nM. The comparison of the optimized model with the experimental data shows an accuracy of more than 95% which verifies that the optimized model is reliable for being used in any application of the graphene-based DNA sensor.

  17. Thermal sensor based zinc oxide diode for low temperature applications

    Energy Technology Data Exchange (ETDEWEB)

    Ocaya, R.O. [Department of Physics, University of the Free State (South Africa); Al-Ghamdi, Ahmed [Department of Physics, Faculty of Science, King Abdulaziz University, Jeddah, 21589 (Saudi Arabia); El-Tantawy, F. [Department of Physics, Faculty of Science, Suez Canal University, Ismailia (Egypt); Center of Nanotechnology, King Abdulaziz University, Jeddah (Saudi Arabia); Farooq, W.A. [Department of Physics and Astronomy, College of Science, King Saud University, Riyadh (Saudi Arabia); Yakuphanoglu, F., E-mail: fyhan@hotmail.com [Department of Physics, Faculty of Science, King Abdulaziz University, Jeddah, 21589 (Saudi Arabia); Department of Physics, Faculty of Science, Firat University, Elazig, 23169 (Turkey)

    2016-07-25

    The device parameters of Al/p-Si/Zn{sub 1-x}Al{sub x}O-NiO/Al Schottky diode for x = 0.005 were investigated over the 50 K–400 K temperature range using direct current–voltage (I–V) and impedance spectroscopy. The films were prepared using the sol–gel method followed by spin-coating on p-Si substrate. The ideality factor, barrier height, resistance and capacitance of the diode were found to depend on temperature. The calculated barrier height has a mean. Capacitance–voltage (C–V) measurements show that the capacitance decreases with increasing frequency, suggesting a continuous distribution of interface states over the surveyed 100 kHz to 1 MHz frequency range. The interface state densities, N{sub ss}, of the diode were calculated and found to peak as functions of bias and temperature in two temperature regions of 50 K–300 K and 300 K–400 K. A peak value of approximately 10{sup 12}/eV cm{sup 2} was observed around 0.7 V bias for 350 K and at 3 × 10{sup 12}/eVcm{sup 2} around 2.2 V bias for 300 K. The relaxation time was found to average 4.7 μs over all the temperatures, but showing its lowest value of 1.58 μs at 300 K. It is seen that the interface states of the diode is controlled by the temperature. This suggests that Al/p-Si/Zn1-xAlxO-NiO/Al diode can be used as a thermal sensors for low temperature applications. - Highlights: • Al/pSi/Zn1-xAlxO-NiO/Al Schottky diode was fabricated by sol gel method. • The interface state density of the diode is controlled by the temperature. • Zinc oxide based diode can be used as a thermal sensor for low temperature applications.

  18. A novel technique to monitor thermal discharges using thermal infrared imaging.

    Science.gov (United States)

    Muthulakshmi, A L; Natesan, Usha; Ferrer, Vincent A; Deepthi, K; Venugopalan, V P; Narasimhan, S V

    2013-09-01

    Coastal temperature is an important indicator of water quality, particularly in regions where delicate ecosystems sensitive to water temperature are present. Remote sensing methods are highly reliable for assessing the thermal dispersion. The plume dispersion from the thermal outfall of the nuclear power plant at Kalpakkam, on the southeast coast of India, was investigated from March to December 2011 using thermal infrared images along with field measurements. The absolute temperature as provided by the thermal infrared (TIR) images is used in the Arc GIS environment for generating a spatial pattern of the plume movement. Good correlation of the temperature measured by the TIR camera with the field data (r(2) = 0.89) make it a reliable method for the thermal monitoring of the power plant effluents. The study portrays that the remote sensing technique provides an effective means of monitoring the thermal distribution pattern in coastal waters.

  19. Recent developments in numerical simulation techniques of thermal recovery processes

    Energy Technology Data Exchange (ETDEWEB)

    Tamim, M. [Bangladesh University of Engineering and Technology, Bangladesh (Bangladesh); Abou-Kassem, J.H. [Chemical and Petroleum Engineering Department, UAE University, Al-Ain 17555 (United Arab Emirates); Farouq Ali, S.M. [University of Alberta, Alberta (Canada)

    2000-05-01

    Numerical simulation of thermal processes (steam flooding, steam stimulation, SAGD, in-situ combustion, electrical heating, etc.) is an integral part of a thermal project design. The general tendency in the last 10 years has been to use commercial simulators. During the last decade, only a few new models have been reported in the literature. More work has been done to modify and refine solutions to existing problems to improve the efficiency of simulators. The paper discusses some of the recent developments in simulation techniques of thermal processes such as grid refinement, grid orientation, effect of temperature on relative permeability, mathematical models, and solution methods. The various aspects of simulation discussed here promote better understanding of the problems encountered in the simulation of thermal processes and will be of value to both simulator users and developers.

  20. Wireless multimedia sensor networks on reconfigurable hardware information reduction techniques

    CERN Document Server

    Ang, Li-minn; Chew, Li Wern; Yeong, Lee Seng; Chia, Wai Chong

    2013-01-01

    Traditional wireless sensor networks (WSNs) capture scalar data such as temperature, vibration, pressure, or humidity. Motivated by the success of WSNs and also with the emergence of new technology in the form of low-cost image sensors, researchers have proposed combining image and audio sensors with WSNs to form wireless multimedia sensor networks (WMSNs).

  1. Exploiting Social Media Sensor Networks through Novel Data Fusion Techniques

    Energy Technology Data Exchange (ETDEWEB)

    Kouri, Tina [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2017-11-01

    Unprecedented amounts of data are continuously being generated by sensors (“hard” data) and by humans (“soft” data), and this data needs to be exploited to its full potential. The first step in exploiting this data is determine how the hard and soft data are related to each other. In this project we fuse hard and soft data, using the attributes of each (e.g., time and space), to gain more information about interesting events. Next, we attempt to use social networking textual data to predict the present (i.e., predict that an interesting event is occurring and details about the event) using data mining, machine learning, natural language processing, and text analysis techniques.

  2. Argonne National Laboratory's thermal plume measurements: instruments and techniques

    International Nuclear Information System (INIS)

    Van Loon, L.S.; Frigo, A.A.; Paddock, R.A.

    1977-12-01

    Instrumentation and techniques were developed at Argonne National Laboratory for measuring the three-dimensional temperature structure of thermal plumes from power plants, along with the limnological, meteorological, and plant operating conditions affecting their behavior. The equipment and procedures were designed to provide field data for use in evaluating predictive models that describe thermal plume behavior, and over 100 sets of these data have been collected. The instrument systems and techniques employed in a typical thermal discharge survey are highly integrated. Continuous monitoring of ambient and plant conditions is coupled with plume mapping from a moving survey boat. The instantaneous location of the boat together with subsurface temperature measurements from a towed thermistor chain provide a quasisynoptic view of the plume structure. Real-time, onboard display of the boat path and vertical temperatures supply feedback to investigators for determining the extent and spatial resolution of measurements required. The unique design, reliability, accuracy, calibration, and historical development of the components of these integrated systems are described. Survey system interfaces with data handling and processing techniques are also explained. Special supportive studies to investigate plume dynamics, values of eddy diffusivities, time-temperature histories of water parcels in thermal plumes, and rapid changes in plume shape are also described along with instrumentation used

  3. Landsat 8 Operational Land Imager (OLI)_Thermal Infared Sensor (TIRS) V1

    Data.gov (United States)

    National Aeronautics and Space Administration — Abstract:The Operational Land Imager (OLI) and Thermal Infrared Sensor (TIRS) are instruments onboard the Landsat 8 satellite, which was launched in February of...

  4. Impact of Soil Water Content on Landmine Detection Using Radar and Thermal Infrared Sensors

    National Research Council Canada - National Science Library

    Hong, Sung-ho

    2001-01-01

    .... The most important of these is water content since it directly influences the three other properties in this study, the ground penetrating radar and thermal infrared sensors were used to identify non...

  5. Evaluation of the AN/SAY-1 Thermal Imaging Sensor System

    National Research Council Canada - National Science Library

    Smith, John G; Middlebrook, Christopher T

    2002-01-01

    The AN/SAY-1 Thermal Imaging Sensor System "TISS" was developed to provide surface ships with a day/night imaging capability to detect low radar reflective, small cross-sectional area targets such as floating mines...

  6. Thermoreflectance temperature imaging of integrated circuits: calibration technique and quantitative comparison with integrated sensors and simulations

    International Nuclear Information System (INIS)

    Tessier, G; Polignano, M-L; Pavageau, S; Filloy, C; Fournier, D; Cerutti, F; Mica, I

    2006-01-01

    Camera-based thermoreflectance microscopy is a unique tool for high spatial resolution thermal imaging of working integrated circuits. However, a calibration is necessary to obtain quantitative temperatures on the complex surface of integrated circuits. The spatial and temperature resolutions reached by thermoreflectance are excellent (360 nm and 2.5 x 10 -2 K in 1 min here), but the precision is more difficult to assess, notably due to the lack of comparable thermal techniques at submicron scales. We propose here a Peltier element control of the whole package temperature in order to obtain calibration coefficients simultaneously on several materials visible on the surface of the circuit. Under high magnifications, movements associated with thermal expansion are corrected using a piezo electric displacement and a software image shift. This calibration method has been validated by comparison with temperatures measured using integrated thermistors and diodes and by a finite volume simulation. We show that thermoreflectance measurements agree within a precision of ±2.3% with the on-chip sensors measurements. The diode temperature is found to underestimate the actual temperature of the active area by almost 70% due to the thermal contact of the diode with the substrate, acting as a heat sink

  7. Ceramic thermal wind sensor based on advanced direct chip attaching package

    International Nuclear Information System (INIS)

    Zhou Lin; Qin Ming; Chen Shengqi; Chen Bei

    2014-01-01

    An advanced direct chip attaching packaged two-dimensional ceramic thermal wind sensor is studied. The thermal wind sensor chip is fabricated by metal lift-off processes on the ceramic substrate. An advanced direct chip attaching (DCA) packaging is adopted and this new packaged method simplifies the processes of packaging further. Simulations of the advanced DCA packaged sensor based on computational fluid dynamics (CFD) model show the sensor can detect wind speed and direction effectively. The wind tunnel testing results show the advanced DCA packaged sensor can detect the wind direction from 0° to 360° and wind speed from 0 to 20 m/s with the error less than 0.5 m/s. The nonlinear fitting based least square method in Matlab is used to analyze the performance of the sensor. (semiconductor devices)

  8. A thermal technique for local ultrasound intensity measurement: part 2. Application to exposimetry on a medical diagnostic device

    International Nuclear Information System (INIS)

    Wilkens, V

    2010-01-01

    Acoustic output measurements on medical ultrasound equipment are usually performed using radiation force balances to determine the output power and using hydrophones to determine pressure and intensity parameters. The local temporal-average ultrasound intensity can be measured alternatively by thermal sensors. The technique was described and prototype sensors were characterized in a preceding paper. Here, the application of such a thermal intensity sensor to the output beam characterization of a typical medical diagnostic device is described. Two transducers, a 7.5 MHz linear array and a 3.5 MHz convex array were investigated in different operating modes. For comparison, hydrophone measurements were also performed. If the spatial averaging effect is taken into account, good agreement is found between both measurement methods. The maximum deviations of the spatial-peak temporal-average intensities I SPTA obtained with the thermal sensor from the corresponding hydrophone-based results were below 12%. The simple thermal technique offers advantages for intensity measurements especially in the case of scanning and combined modes of the diagnostic device, where the synchronization between hydrophone measurements and the complex pulse emission pattern can be difficult

  9. Using Collar worn Sensors to Forecast Thermal Strain in Military Working Dogs

    Science.gov (United States)

    2016-04-22

    Using Collar-worn Sensors to Forecast Thermal Strain in Military Working Dogs James R. Williamson, Austin R. Hess, Christopher J. Smalt, Delsey M...these estimates for forecasting and monitoring thermal strain is assessed based on performance in out of sample prediction of core temperature (Tc...time step (100 Hz) from the magnitude of the three- dimensional acceleration vector, ai , which is independent of sensor orientation. Next, the

  10. Sensors

    Energy Technology Data Exchange (ETDEWEB)

    Jensen, H. [PBI-Dansensor A/S (Denmark); Toft Soerensen, O. [Risoe National Lab., Materials Research Dept. (Denmark)

    1999-10-01

    A new type of ceramic oxygen sensors based on semiconducting oxides was developed in this project. The advantage of these sensors compared to standard ZrO{sub 2} sensors is that they do not require a reference gas and that they can be produced in small sizes. The sensor design and the techniques developed for production of these sensors are judged suitable by the participating industry for a niche production of a new generation of oxygen sensors. Materials research on new oxygen ion conducting conductors both for applications in oxygen sensors and in fuel was also performed in this project and finally a new process was developed for fabrication of ceramic tubes by dip-coating. (EHS)

  11. Low-Power Silicon-based Thermal Sensors and Actuators for Chemical Applications

    NARCIS (Netherlands)

    Vereshchagina, E.

    2011-01-01

    In the Hot Silicon project low and ultra-low-power Si-based hot surface devices have been developed, i.e. thermal sensors and actuators, for application in catalytic gas micro sensors, micro- and nano- calorimeters. This work include several scientific and technological aspects: • Design and

  12. Effects of Cyclic Thermal Load on the Signal Characteristics of FBG Sensors Packaged with Epoxy Adhesives

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Heonyoung; Kang, Donghoon [Korea Railroad Research Institute, Uiwang (Korea, Republic of)

    2017-04-15

    Fiber optics sensors that have been mainly applied to aerospace areas are now finding applicability in other areas, such as transportation, including railways. Among the sensors, the fiber Bragg grating (FBG) sensors have led to a steep increase due to their properties of absolute measurement and multiplexing capability. Generally, the FBG sensors adhere to structures and sensing modules using adhesives such as an epoxy. However, the measurement errors that occurred when the FBG sensors were used in a long-term application, where they were exposed to environmental thermal load, required calibration. For this reason, the thermal curing of adhesives needs to be investigated to enhance the reliability of the FBG sensor system. This can be done at room temperature through cyclic thermal load tests using four types of specimens. From the test results, it is confirmed that residual compressive strain occurs to the FBG sensors due to an initial cyclic thermal load. In conclusion, signals of the FBG sensors need to be stabilized for applying them to a long-term SHM.

  13. Investigation of the sensitivity of MIS-sensor to thermal decomposition products of cables insulation

    Science.gov (United States)

    Filipchuk, D. V.; Litvinov, A. V.; Etrekova, M. O.; Nozdrya, D. A.

    2017-12-01

    Sensitivity of the MIS-sensor to products of thermal decomposition of insulation and jacket of the most common types of cables is investigated. It is shown that hydrogen is evolved under heating the insulation to temperatures not exceeding 250 °C. Registration of the evolved hydrogen by the MIS-sensor can be used for detection of fires at an early stage.

  14. Optical thermal sensor based on cholesteric film refilled with mixture of toluene and ethanol.

    Science.gov (United States)

    Li, Yong; Liu, Yanjun; Luo, Dan

    2017-10-16

    We demonstrate an optical thermal sensor based on cholesteric film refilled with mixture of toluene and ethanol. The thermal response mechanism is mainly based on the thermal expansion effect induce by toluene, where the ethanol is used for refractive index adjustment to determine the initial refection band position of cholesteric film. The ethanol-toluene mixture was used to adjust the color tunability with the temperature in relation with the habits of people (blue as cold, green as safe and red as hot). A broad temperature range of 86 °C and highly sensitivity of 1.79 nm/ °C are achieved in proposed thermal sensor, where the reflective color red-shifts from blue to red when environmental temperature increases from -6 °C to 80 °C. This battery-free thermal sensor possesses features including simple fabrication, low-cost, and broad temperature sensing range, showing potential application in scientific research and industry.

  15. Measurements of He II Thermal Counterflow Using PIV Technique

    International Nuclear Information System (INIS)

    Zhang, T.; Van Sciver, S.W.

    2004-01-01

    Our previous experiments on the measurements of He II thermal counterflow using Particle Image Velocimetry (PIV) have shown that there exists a substantial discrepancy between the measured and theoretical values of normal fluid velocity. It was assumed that this is due to the slip velocity between tracer particles and liquid helium. In the present work, tracer particles with a much smaller mean diameter and a more uniform size distribution were selected in order to reduce the effect of slip velocity, and an improved two phase fluidized bed technique was used to introduce the particles into liquid helium. The normal fluid velocity of thermal counterflow was then measured using the PIV technique at various heat fluxes and bath temperatures. The experimental results, however, still show the existence of discrepancy between PIV measured particle velocities and the theoretical normal fluid velocity. A preliminary explanation of these results is given based on an interaction of tracer particles with the superfluid component in the He II

  16. TIGER: Development of Thermal Gradient Compensation Algorithms and Techniques

    Science.gov (United States)

    Hereford, James; Parker, Peter A.; Rhew, Ray D.

    2004-01-01

    In a wind tunnel facility, the direct measurement of forces and moments induced on the model are performed by a force measurement balance. The measurement balance is a precision-machined device that has strain gages at strategic locations to measure the strain (i.e., deformations) due to applied forces and moments. The strain gages convert the strain (and hence the applied force) to an electrical voltage that is measured by external instruments. To address the problem of thermal gradients on the force measurement balance NASA-LaRC has initiated a research program called TIGER - Thermally-Induced Gradients Effects Research. The ultimate goals of the TIGER program are to: (a) understand the physics of the thermally-induced strain and its subsequent impact on load measurements and (b) develop a robust thermal gradient compensation technique. This paper will discuss the impact of thermal gradients on force measurement balances, specific aspects of the TIGER program (the design of a special-purpose balance, data acquisition and data analysis challenges), and give an overall summary.

  17. Spontaneous high piezoelectricity in poly(vinylidene fluoride) nanoribbons produced by iterative thermal size reduction technique.

    Science.gov (United States)

    Kanik, Mehmet; Aktas, Ozan; Sen, Huseyin Sener; Durgun, Engin; Bayindir, Mehmet

    2014-09-23

    We produced kilometer-long, endlessly parallel, spontaneously piezoelectric and thermally stable poly(vinylidene fluoride) (PVDF) micro- and nanoribbons using iterative size reduction technique based on thermal fiber drawing. Because of high stress and temperature used in thermal drawing process, we obtained spontaneously polar γ phase PVDF micro- and nanoribbons without electrical poling process. On the basis of X-ray diffraction (XRD) analysis, we observed that PVDF micro- and nanoribbons are thermally stable and conserve the polar γ phase even after being exposed to heat treatment above the melting point of PVDF. Phase transition mechanism is investigated and explained using ab initio calculations. We measured an average effective piezoelectric constant as -58.5 pm/V from a single PVDF nanoribbon using a piezo evaluation system along with an atomic force microscope. PVDF nanoribbons are promising structures for constructing devices such as highly efficient energy generators, large area pressure sensors, artificial muscle and skin, due to the unique geometry and extended lengths, high polar phase content, high thermal stability and high piezoelectric coefficient. We demonstrated two proof of principle devices for energy harvesting and sensing applications with a 60 V open circuit peak voltage and 10 μA peak short-circuit current output.

  18. SENSOR++: Simulation of Remote Sensing Systems from Visible to Thermal Infrared

    Science.gov (United States)

    Paproth, C.; Schlüßler, E.; Scherbaum, P.; Börner, A.

    2012-07-01

    During the development process of a remote sensing system, the optimization and the verification of the sensor system are important tasks. To support these tasks, the simulation of the sensor and its output is valuable. This enables the developers to test algorithms, estimate errors, and evaluate the capabilities of the whole sensor system before the final remote sensing system is available and produces real data. The presented simulation concept, SENSOR++, consists of three parts. The first part is the geometric simulation which calculates where the sensor looks at by using a ray tracing algorithm. This also determines whether the observed part of the scene is shadowed or not. The second part describes the radiometry and results in the spectral at-sensor radiance from the visible spectrum to the thermal infrared according to the simulated sensor type. In the case of earth remote sensing, it also includes a model of the radiative transfer through the atmosphere. The final part uses the at-sensor radiance to generate digital images by using an optical and an electronic sensor model. Using SENSOR++ for an optimization requires the additional application of task-specific data processing algorithms. The principle of the simulation approach is explained, all relevant concepts of SENSOR++ are discussed, and first examples of its use are given, for example a camera simulation for a moon lander. Finally, the verification of SENSOR++ is demonstrated.

  19. Reliability evaluation of fiber optic sensors exposed to cyclic thermal load

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Heon Young; Kim, Dong Hoon [Advanced Materials Research Team, Korea Railroad Research Institute, Uiwang (Korea, Republic of); Kim, Dae Hyun [Dept. of Mechanical and Automotive Engineering, Seoul National University of Science and Technology, Seoul (Korea, Republic of)

    2016-06-15

    Fiber Bragg grating (FBG) sensors are currently the most prevalent sensors because of their unique advantages such as ease of multiplexing and capability of performing absolute measurements. They are applied to various structures for structural health monitoring (SHM). The signal characteristics of FBG sensors under thermal loading should be investigated to enhance the reliability of these sensors, because they are exposed to certain cyclic thermal loads due to temperature changes resulting from change of seasons, when they are applied to structures for SHM. In this study, tests on specimens are conducted in a thermal chamber with temperature changes from - to for 300 cycles. For the specimens, two types of base materials and adhesives that are normally used in the manufacture of packaged FBG sensors are selected. From the test results, it is confirmed that the FBG sensors undergo some degree of compressive strain under cyclic thermal load; this can lead to measurement errors. Hence, a pre-calibration is necessary before applying these sensors to structures for long-term SHM.

  20. Use of advanced modeling techniques to optimize thermal packaging designs.

    Science.gov (United States)

    Formato, Richard M; Potami, Raffaele; Ahmed, Iftekhar

    2010-01-01

    Through a detailed case study the authors demonstrate, for the first time, the capability of using advanced modeling techniques to correctly simulate the transient temperature response of a convective flow-based thermal shipper design. The objective of this case study was to demonstrate that simulation could be utilized to design a 2-inch-wall polyurethane (PUR) shipper to hold its product box temperature between 2 and 8 °C over the prescribed 96-h summer profile (product box is the portion of the shipper that is occupied by the payload). Results obtained from numerical simulation are in excellent agreement with empirical chamber data (within ±1 °C at all times), and geometrical locations of simulation maximum and minimum temperature match well with the corresponding chamber temperature measurements. Furthermore, a control simulation test case was run (results taken from identical product box locations) to compare the coupled conduction-convection model with a conduction-only model, which to date has been the state-of-the-art method. For the conduction-only simulation, all fluid elements were replaced with "solid" elements of identical size and assigned thermal properties of air. While results from the coupled thermal/fluid model closely correlated with the empirical data (±1 °C), the conduction-only model was unable to correctly capture the payload temperature trends, showing a sizeable error compared to empirical values (ΔT > 6 °C). A modeling technique capable of correctly capturing the thermal behavior of passively refrigerated shippers can be used to quickly evaluate and optimize new packaging designs. Such a capability provides a means to reduce the cost and required design time of shippers while simultaneously improving their performance. Another advantage comes from using thermal modeling (assuming a validated model is available) to predict the temperature distribution in a shipper that is exposed to ambient temperatures which were not bracketed

  1. Review Of Prevention Techniques For Denial Of Service DOS Attacks In Wireless Sensor Network

    Directory of Open Access Journals (Sweden)

    Poonam Rolla

    2015-08-01

    Full Text Available Wireless Sensor Networks comprised of several tiny sensor nodes which are densely deployed over the region to monitor the environmental conditions. These sensor nodes have certain design issues out of which security is the main predominant factor as it effects the whole lifetime of network. DDoS Distributed denial of service attack floods unnecessary packets in the sensor network. A review on DDoS attacks and their prevention techniques have been done in this paper.

  2. Detection of thermal aging degradation and plastic strain damage for duplex stainless steel using SQUID sensor

    International Nuclear Information System (INIS)

    Otaka, M.; Evanson, S.; Hesegawa, K.; Takaku, K.

    1991-01-01

    An apparatus using a SQUID sensor is developed for nondestructive inspection. The measurements are obtained with the SQUID sensor located approximately 150 mm from the specimen. The degradation of thermal aging and plastic strain for duplex stainless steel is successfully detected independently from the magnetic characterization measurements. The magnetic flux density under high polarizing field is found to be independent of thermal aging. Coercive force increases with thermal aging time. On the other hand, the magnetic flux density under high field increases with the plastic strain. Coercive force is found to be independent of the plastic strain. (author)

  3. Using geophysical techniques to control in situ thermal remediation

    International Nuclear Information System (INIS)

    Boyd, S.; Daily, W.; Ramirez, A.; Wilt, M.; Goldman, R.; Kayes, D.; Kenneally, K.; Udell, K.; Hunter, R.

    1994-01-01

    Monitoring the thermal and hydrologic processes that occur during thermal environmental remediation programs in near real-time provides essential information for controlling the process. Geophysical techniques played a crucial role in process control as well as for characterization during the recent Dynamic Underground Stripping Project demonstration in which several thousand gallons of gasoline were removed from heterogeneous soils both above and below the water table. Dynamic Underground Stripping combines steam injection and electrical heating for thermal enhancement with ground water pumping and vacuum extraction for contaminant removal. These processes produce rapid changes in the subsurface properties including changes in temperature fluid saturation, pressure and chemistry. Subsurface imaging methods are used to map the heated zones and control the thermal process. Temperature measurements made in wells throughout the field reveal details of the complex heating phenomena. Electrical resistance tomography (ERT) provides near real-time detailed images of the heated zones between boreholes both during electrical heating and steam injection. Borehole induction logs show close correlation with lithostratigraphy and, by identifying the more permeable gravel zones, can be used to predict steam movement. They are also useful in understanding the physical changes in the field and in interpreting the ERT images. Tiltmeters provide additional information regarding the shape of the steamed zones in plan view. They were used to track the growth of the steam front from individual injectors

  4. Recession-Tolerant Sensors for Thermal Protection Systems, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — The Phase II project will develop a suite of diagnostic sensors using Direct Write technology to measure temperature, surface recession depth, and heat flux of an...

  5. Synchrotron X-ray measurement techniques for thermal barrier coated cylindrical samples under thermal gradients

    Energy Technology Data Exchange (ETDEWEB)

    Siddiqui, Sanna F.; Knipe, Kevin; Manero, Albert; Raghavan, Seetha [Department of Mechanical and Aerospace Engineering, University of Central Florida, Orlando, Florida 32816 (United States); Meid, Carla; Wischek, Janine; Bartsch, Marion [German Aerospace Center (DLR), Institute of Materials Research, 51147 Cologne (Germany); Okasinski, John; Almer, Jonathan [X-Ray Science Division, Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439 (United States); Karlsson, Anette M. [Cleveland State University, 2121 Euclid Avenue, Cleveland, Ohio 44115 (United States)

    2013-08-15

    Measurement techniques to obtain accurate in situ synchrotron strain measurements of thermal barrier coating systems (TBCs) applied to hollow cylindrical specimens are presented in this work. The Electron Beam Physical Vapor Deposition coated specimens with internal cooling were designed to achieve realistic temperature gradients over the TBC coated material such as that occurring in the turbine blades of aeroengines. Effects of the circular cross section on the x-ray diffraction (XRD) measurements in the various layers, including the thermally grown oxide, are investigated using high-energy synchrotron x-rays. Multiple approaches for beam penetration including collection, tangential, and normal to the layers, along with variations in collection parameters are compared for their ability to attain high-resolution XRD data from the internal layers. This study displays the ability to monitor in situ, the response of the internal layers within the TBC, while implementing a thermal gradient across the thickness of the coated sample. The thermal setup maintained coating surface temperatures in the range of operating conditions, while monitoring the substrate cooling, for a controlled thermal gradient. Through variation in measurement location and beam parameters, sufficient intensities are obtained from the internal layers which can be used for depth resolved strain measurements. Results are used to establish the various techniques for obtaining XRD measurements through multi-layered coating systems and their outcomes will pave the way towards goals in achieving realistic in situ testing of these coatings.

  6. Equivalent thermal history reconstruction from a partially crystallized glass-ceramic sensor array

    Science.gov (United States)

    Heeg, Bauke

    2015-11-01

    The basic concept of a thermal history sensor is that it records the accumulated exposure to some unknown, typically varying temperature profile for a certain amount of time. Such a sensor is considered to be capable of measuring the duration of several (N) temperature intervals. For this purpose, the sensor deploys multiple (M) sensing elements, each with different temperature sensitivity. At the end of some thermal exposure for a known period of time, the sensor array is read-out and an estimate is made of the set of N durations of the different temperature ranges. A potential implementation of such a sensor was pioneered by Fair et al. [Sens. Actuators, A 141, 245 (2008)], based on glass-ceramic materials with different temperature-dependent crystallization dynamics. In their work, it was demonstrated that an array of sensor elements can be made sensitive to slight differences in temperature history. Further, a forward crystallization model was used to simulate the variations in sensor array response to differences in the temperature history. The current paper focusses on the inverse aspect of temperature history reconstruction from a hypothetical sensor array output. The goal of such a reconstruction is to find an equivalent thermal history that is the closest representation of the true thermal history, i.e., the durations of a set of temperature intervals that result in a set of fractional crystallization values which is closest to the one resulting from the true thermal history. One particular useful simplification in both the sensor model as well as in its practical implementation is the omission of nucleation effects. In that case, least squares models can be used to approximate the sensor response and make reconstruction estimates. Even with this simplification, sensor noise can have a destabilizing effect on possible reconstruction solutions, which is evaluated using simulations. Both regularization and non-negativity constrained least squares

  7. Thermal Stability of Magnetic Compass Sensor for High Accuracy Positioning Applications

    Directory of Open Access Journals (Sweden)

    Van-Tang PHAM

    2015-12-01

    Full Text Available Using magnetic compass sensors in angle measurements have a wide area of application such as positioning, robot, landslide, etc. However, one of the most phenomenal that affects to the accuracy of the magnetic compass sensor is the temperature. This paper presents two thermal stability schemes for improving performance of a magnetic compass sensor. The first scheme uses the feedforward structure to adjust the angle output of the compass sensor adapt to the variation of the temperature. The second scheme increases both the temperature working range and steady error performance of the sensor. In this scheme, we try to keep the temperature of the sensor is stable at the certain value (e.g. 25 oC by using a PID (proportional-integral-derivative controller and a heating/cooling generator. Many experiment scenarios have implemented to confirm the effectivity of these solutions.

  8. Novel Damage Detection Techniques for Structural Health Monitoring Using a Hybrid Sensor

    Directory of Open Access Journals (Sweden)

    Dengjiang Wang

    2016-01-01

    Full Text Available This study presents a technique for detecting fatigue cracks based on a hybrid sensor monitoring system consisting of a combination of intelligent coating monitoring (ICM and piezoelectric transducer (PZT sensors. An experimental procedure using this hybrid sensor system was designed to monitor the cracks generated by fatigue testing in plate structures. A probability of detection (POD model that quantifies the reliability of damage detection for a specific sensor or the nondestructive testing (NDT method was used to evaluate the weight factor for the ICM and PZT sensors. To estimate the uncertainty of model parameters in this study, the Bayesian method was employed. Realistic data from fatigue testing was used to validate the overall method, and the results show that the novel damage detection technique using a hybrid sensor can quantify fatigue cracks more accurately than results obtained by conventional sensor methods.

  9. Carbon filter property detection with thermal neutron technique

    International Nuclear Information System (INIS)

    Deng Zhongbo; Han Jun; Li Wenjie

    2003-01-01

    The paper discussed the mechanism that the antigas property of the carbon filter will decrease because of its carbon bed absorbing water from the air while the carbon filter is being stored, and introduced the principle and method of detection the amount of water absorption with thermal neutron technique. Because some certain relation between the antigas property of the carbon filter and the amount of water absorption exists, the decrease degree of the carbon filter antigas property can be estimated through the amount of water absorption, offering a practicable facility technical pathway to quickly non-destructively detect the carbon filter antigas property

  10. The development of monitoring techniques for thermal stratification in nuclear plant piping

    International Nuclear Information System (INIS)

    Sim, Cheul Muu; Joo, Young Sang; Yoon, Kwang Sik; Park, Chi Seung; Choi, Ha Lim; Moon, Jae Wha; Bae, Sang Ho.

    1996-12-01

    The conventional nondestructive testing has been performed in those area which are susceptible to thermal stress in according to NRC 88-08,11. In addition to that, it is necessary to set up a monitoring system to prevent severe thermal stress to pipes in early stages and to develop the non-intrusive techniques to diagnose the check valve because the thermal stratification has been caused by the malfunction of the check valve in ECCS pipe. Thermal stratification monitoring system has been designed and installed at ECCS line permanently and surge line temporally in YG nuclear power plant. The data is acceptable in according to TASCS guide line. Also, the data originated from ISMS is useful for the arrangement of a special UT program and stress analysis. Applying a togetherness of acoustics and magnetics signal, it is possible to determine the parameters of the function of the check valve internals without disassembling it. This series of tests show that the accelerometers can be use d to measure and to differentiate the three types of impacts; metal to metal impacts mechanical rubs, and worn internal parts. The magnet sensors can be used to detect the opening/closing of stainless check and fluttering of disk. (author). 50 refs., 5 tabs., 28 figs

  11. The development of monitoring techniques for thermal stratification in nuclear plant piping

    Energy Technology Data Exchange (ETDEWEB)

    Sim, Cheul Muu; Joo, Young Sang; Yoon, Kwang Sik; Park, Chi Seung; Choi, Ha Lim; Moon, Jae Wha; Bae, Sang Ho

    1996-12-01

    The conventional nondestructive testing has been performed in those area which are susceptible to thermal stress in according to NRC 88-08,11. In addition to that, it is necessary to set up a monitoring system to prevent severe thermal stress to pipes in early stages and to develop the non-intrusive techniques to diagnose the check valve because the thermal stratification has been caused by the malfunction of the check valve in ECCS pipe. Thermal stratification monitoring system has been designed and installed at ECCS line permanently and surge line temporally in YG nuclear power plant. The data is acceptable in according to TASCS guide line. Also, the data originated from ISMS is useful for the arrangement of a special UT program and stress analysis. Applying a togetherness of acoustics and magnetics signal, it is possible to determine the parameters of the function of the check valve internals without disassembling it. This series of tests show that the accelerometers can be use d to measure and to differentiate the three types of impacts; metal to metal impacts mechanical rubs, and worn internal parts. The magnet sensors can be used to detect the opening/closing of stainless check and fluttering of disk. (author). 50 refs., 5 tabs., 28 figs.

  12. Thermal mapping of mountain slopes on Mars by application of a Differential Apparent Thermal Inertia technique

    Science.gov (United States)

    Kubiak, Marta; Mège, Daniel; Gurgurewicz, Joanna; Ciazela, Jakub

    2015-04-01

    Thermal inertia (P) is an important property of geologic surfaces that essentially describes the resistance to temperature (T) change as heat is added. Most remote sensing data describe the surface only. P is a volume property that is sensitive to the composition of the subsurface, down to a depth reached by the diurnal heating wave. As direct measurement of P is not possible on Mars, thermal inertia models (Fergason et al., 2006) and deductive methods (the Apparent Thermal Inertia: ATI and Differential Apparent Thermal Inertia: DATI) are used to estimate it. ATI is computed as (1 - A) / (Tday - Tnight), where A is albedo. Due to the lack of the thermal daytime images with maximum land surface temperature (LST) and nighttime images with minimum LST in Valles Marineris region, the ATI method is difficult to apply. Instead, we have explored the DATI technique (Sabol et al., 2006). DATI is calculated based on shorter time (t) intervals with a high |ΔT/Δt| gradient (in the morning or in the afternoon) and is proportional to the day/night temperature difference (ATI), and hence P. Mars, which exhibits exceptionally high |ΔT/Δt| gradients due to the lack of vegetation and thin atmosphere, is especially suitable for the DATI approach. Here we present a new deductive method for high-resolution differential apparent thermal inertia (DATI) mapping for areas of highly contrasted relief (e.g., Valles Marineris). Contrary to the thermal inertia models, our method takes local relief characteristics (slopes and aspects) into account. This is crucial as topography highly influences A and ΔT measurements. In spite of the different approach, DATI values in the flat areas are in the same range as the values obtained by Fergason et al. (2006). They provide, however, more accurate information for geological interpretations of hilly or mountainous terrains. Sabol, D. E., Gillespie, A. R., McDonald, E., and Danilina, I., 2006. Differential Thermal Inertia of Geological Surfaces. In

  13. Drift Correction of Lightweight Microbolometer Thermal Sensors On-Board Unmanned Aerial Vehicles

    Directory of Open Access Journals (Sweden)

    Francisco-Javier Mesas-Carrascosa

    2018-04-01

    Full Text Available The development of lightweight sensors compatible with mini unmanned aerial vehicles (UAVs has expanded the agronomical applications of remote sensing. Of particular interest in this paper are thermal sensors based on lightweight microbolometer technology. These are mainly used to assess crop water stress with thermal images where an accuracy greater than 1 °C is necessary. However, these sensors lack precise temperature control, resulting in thermal drift during image acquisition that requires correction. Currently, there are several strategies to manage thermal drift effect. However, these strategies reduce useful flight time over crops due to the additional in-flight calibration operations. This study presents a drift correction methodology for microbolometer sensors based on redundant information from multiple overlapping images. An empirical study was performed in an orchard of high-density hedgerow olive trees with flights at different times of the day. Six mathematical drift correction models were developed and assessed to explain and correct drift effect on thermal images. Using the proposed methodology, the resulting thermally corrected orthomosaics yielded a rate of error lower than 1° C compared to those where no drift correction was applied.

  14. 3-D thermal weight function method and multiple virtual crack extension technique for thermal shock problems

    International Nuclear Information System (INIS)

    Lu Yanlin; Zhou Xiao; Qu Jiadi; Dou Yikang; He Yinbiao

    2005-01-01

    An efficient scheme, 3-D thermal weight function (TWF) method, and a novel numerical technique, multiple virtual crack extension (MVCE) technique, were developed for determination of histories of transient stress intensity factor (SIF) distributions along 3-D crack fronts of a body subjected to thermal shock. The TWF is a universal function, which is dependent only on the crack configuration and body geometry. TWF is independent of time during thermal shock, so the whole history of transient SIF distributions along crack fronts can be directly calculated through integration of the products of TWF and transient temperatures and temperature gradients. The repeated determinations of the distributions of stresses (or displacements) fields for individual time instants are thus avoided in the TWF method. An expression of the basic equation for the 3-D universal weight function method for Mode I in an isotropic elastic body is derived. This equation can also be derived from Bueckner-Rice's 3-D WF formulations in the framework of transformation strain. It can be understood from this equation that the so-called thermal WF is in fact coincident with the mechanical WF except for some constants of elasticity. The details and formulations of the MVCE technique are given for elliptical cracks. The MVCE technique possesses several advantages. The specially selected linearly independent VCE modes can directly be used as shape functions for the interpolation of unknown SIFs. As a result, the coefficient matrix of the final system of equations in the MVCE method is a triple-diagonal matrix and the values of the coefficients on the main diagonal are large. The system of equations has good numerical properties. The number of linearly independent VCE modes that can be introduced in a problem is unlimited. Complex situations in which the SIFs vary dramatically along crack fronts can be numerically well simulated by the MVCE technique. An integrated system of programs for solving the

  15. A highly sensitive and durable electrical sensor for liquid ethanol using thermally-oxidized mesoporous silicon

    Science.gov (United States)

    Harraz, Farid A.; Ismail, Adel A.; Al-Sayari, S. A.; Al-Hajry, A.; Al-Assiri, M. S.

    2016-12-01

    A capacitive detection of liquid ethanol using reactive, thermally oxidized films constructed from electrochemically synthesized porous silicon (PSi) is demonstrated. The sensor elements are fabricated as meso-PSi (pore sizes hydrophobic PSi surface exhibited almost a half sensitivity of the thermal oxide sensor. The response to water is achieved only at the oxidized surface and found to be ∼one quarter of the ethanol sensitivity, dependent on parameters such as vapor pressure and surface tension. The capacitance response retains ∼92% of its initial value after continuous nine cyclic runs and the sensors presumably keep long-term stability after three weeks storage, demonstrating excellent durability and storage stability. The observed behavior in current system is likely explained by the interface interaction due to dipole moment effect. The results suggest that the current sensor structure and design can be easily made to produce notably higher sensitivities for reversible detection of various analytes.

  16. A novel low-power fluxgate sensor using a macroscale optimisation technique for space physics instrumentation

    Science.gov (United States)

    Dekoulis, G.; Honary, F.

    2007-05-01

    This paper describes the design of a novel low-power single-axis fluxgate sensor. Several soft magnetic alloy materials have been considered and the choice was based on the balance between maximum permeability and minimum saturation flux density values. The sensor has been modelled using the Finite Integration Theory (FIT) method. The sensor was imposed to a custom macroscale optimisation technique that significantly reduced the power consumption by a factor of 16. The results of the sensor's optimisation technique will be used, subsequently, in the development of a cutting-edge ground based magnetometer for the study of the complex solar wind-magnetospheric-ionospheric system.

  17. Sensor 17 Thermal Isolation Mounting Structure (TIMS) Design Improvements

    Energy Technology Data Exchange (ETDEWEB)

    Enstrom, K. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2015-09-04

    The SENSOR 17 thermographic camera weighs approximately 0.5lbs, has a fundamental mode of 167 Hz, and experiences 0.75W of heat leakage in through the TIMS. The configuration, shown in Figure 1, is comprised of four 300 Series SST washers paired in tandem with P.E.I (Ultem 100) washers. The SENSOR 17 sensor is mounted to a 300 series stainless plate with A-shaped arms. The Plate can be assumed to be at ambient temperatures (≈293K) and the I.R. Mount needs to be cooled to 45K. It is attached to the tip of a cryocooler by a ‘cold strap’ and is assumed to be at the temperature of the cold-strap (≈45K). During flights SENSOR 17 experiences excitations at frequencies centered around 10-30Hz, 60Hz, and 120Hz from the aircraft flight environment. The temporal progression described below depicts the 1st Modal shape at the systems resonant frequency. This simulation indicates Modal articulation will cause a pitch rate of the camera with respect to the body axis of the airplane. This articulation shows up as flutter in the camera.

  18. Under-Sodium Inspection Techniques for Reactor Internals of KALIMER-600 using Ultrasonic Waveguide Sensor

    International Nuclear Information System (INIS)

    Joo, Young Sang; Kim, Seok Hoon; Lee, Jae Han

    2005-01-01

    KALIMER-600 is a pool type liquid metal reactor (LMR) which is operated with a sodium coolant. The reactor internals of KALIMER-600 are submerged in a liquid sodium pool. As the liquid sodium is opaque to the light, a conventional visual inspection can not be used for observing the internal structures under a sodium condition. An under-sodium viewing (USV) technique using an ultrasonic wave should be applied for the observation of the refueling maneuver and the in-service inspection of the reactor internals. Under-sodium inspection technology utilizing ultrasonic waves has been widely developed for a visualization of the reactor core and internal components of LMR. Immersion sensors and waveguide sensors have been applied to the USV inspection. The immersion sensor has a precise imaging capability, but may have high temperature restrictions and an uncertain life. The waveguide sensor has the advantages of simplicity and reliability, but limited in its movement. The new plate-type waveguide sensor has been developed as a useful alternative to immersion sensors for USV applications. In the viewing and monitoring applications, a beam steering function of a waveguide sensor might be required. A new waveguide sensor and technique are being developed to overcome the limitations of a waveguide ultrasonic sensor. In this study, the under-sodium inspection techniques using the newly developed waveguide sensor for the reactor internal structures of KALIMER-600 is proposed

  19. Optical temperature sensor and thermal expansion measurement using a femtosecond micromachined grating in 6H-SiC.

    Science.gov (United States)

    DesAutels, G Logan; Powers, Peter; Brewer, Chris; Walker, Mark; Burky, Mark; Anderson, Gregg

    2008-07-20

    An optical temperature sensor was created using a femtosecond micromachined diffraction grating inside transparent bulk 6H-SiC, and to the best of our knowledge, this is a novel technique of measuring temperature. Other methods of measuring temperature using fiber Bragg gratings have been devised by other groups such as Zhang and Kahrizi [in MEMS, NANO, and Smart Systems (IEEE, 2005)]. This temperature sensor was, to the best of our knowledge, also used for a novel method of measuring the linear and nonlinear coefficients of the thermal expansion of transparent and nontransparent materials by means of the grating first-order diffracted beam. Furthermore the coefficient of thermal expansion of 6H-SiC was measured using this new technique. A He-Ne laser beam was used with the SiC grating to produce a first-order diffracted beam where the change in deflection height was measured as a function of temperature. The grating was micromachined with a 20 microm spacing and has dimensions of approximately 500 microm x 500 microm (l x w) and is roughly 0.5 microm deep into the 6H-SiC bulk. A minimum temperature of 26.7 degrees C and a maximum temperature of 399 degrees C were measured, which gives a DeltaT of 372.3 degrees C. The sensitivity of the technique is DeltaT=5 degrees C. A maximum deflection angle of 1.81 degrees was measured in the first-order diffracted beam. The trend of the deflection with increasing temperature is a nonlinear polynomial of the second-order. This optical SiC thermal sensor has many high-temperature electronic applications such as aircraft turbine and gas tank monitoring for commercial and military applications.

  20. Boundary Layer Separation and Reattachment Detection on Airfoils by Thermal Flow Sensors

    Directory of Open Access Journals (Sweden)

    Peter Busche

    2012-10-01

    Full Text Available A sensor concept for detection of boundary layer separation (flow separation, stall and reattachment on airfoils is introduced in this paper. Boundary layer separation and reattachment are phenomena of fluid mechanics showing characteristics of extinction and even inversion of the flow velocity on an overflowed surface. The flow sensor used in this work is able to measure the flow velocity in terms of direction and quantity at the sensor’s position and expected to determine those specific flow conditions. Therefore, an array of thermal flow sensors has been integrated (flush-mounted on an airfoil and placed in a wind tunnel for measurement. Sensor signals have been recorded at different wind speeds and angles of attack for different positions on the airfoil. The sensors used here are based on the change of temperature distribution on a membrane (calorimetric principle. Thermopiles are used as temperature sensors in this approach offering a baseline free sensor signal, which is favorable for measurements at zero flow. Measurement results show clear separation points (zero flow and even negative flow values (back flow for all sensor positions. In addition to standard silicon-based flow sensors, a polymer-based flexible approach has been tested showing similar results.

  1. Advanced interfacing techniques for sensors measurement circuits and systems for intelligent sensors

    CERN Document Server

    Roy, Joyanta; Kumar, V; Mukhopadhyay, Subhas

    2017-01-01

    This book presents ways of interfacing sensors to the digital world, and discusses the marriage between sensor systems and the IoT: the opportunities and challenges. As sensor output is often affected by noise and interference, the book presents effective schemes for recovering the data from a signal that is buried in noise. It also explores interesting applications in the area of health care, un-obstructive monitoring and the electronic nose and tongue. It is a valuable resource for engineers and scientists in the area of sensors and interfacing wanting to update their knowledge of the latest developments in the field and learn more about sensing applications and challenges.

  2. STUDY OF THE IMPACT OF THERMAL DRIFT ON RELIABILITY OF PRESSURE SENSORS

    Directory of Open Access Journals (Sweden)

    ABDELAZIZ BEDDIAF

    2017-10-01

    Full Text Available Piezoresistive pressure sensors, using a Wheatstone bridge with the piezoresistors, are typically supplied with a voltage ranging from 3 to 10 V involve thermal drift caused by Joule heating. In this paper, an accurate numerical model for optimization and predicting the thermal drift in piezoresistive pressure sensors due to the electric heater in its piezoresistors is adopted. In this case, by using the solution of 2D heat transfer equation considering Joule heating in Cartesian coordinates for the transient regime, we determine how the temperature affects the sensor when the supply voltage is applied. For this, the elevation of temperature due to the Joule heating has been calculated for various values of supply voltage and for several operating times of the sensor; by varying different geometrical parameters. Otherwise, the variation of the coefficient 44 in p-Si and pressure sensitivity as a function of the applied potential, as well as, for various times, for different dimensions of the device, have been also established. It is observed that the electrical heating leads to an important temperature rise in the piezoresistor. Consequently, it causes drift in the pressure sensitivity of the sensor upon application of a voltage. Finally, this work allows us to evaluate the reliability of sensors. Also, it permits to predict their behaviour against temperature due to the application of a voltage of a bridge and to minimize this effect by optimizing the geometrical parameters of the sensor and by reducing the supply voltage.

  3. Monolithic micro-electro-thermal actuator integrated with a lateral displacement sensor

    International Nuclear Information System (INIS)

    Zhang, Yan; Choi, Young-Soo; Lee, Dong-Weon

    2010-01-01

    This paper presents monolithically fabricated horizontal thermal actuators integrated with piezoresistive sensors for in situ displacement sensing. The great advantage of a hybrid system is the use of closed feedback control for improving the transient response of a thermal actuator and positioning accuracy. It consists of two 'hot arms' made of doped silicon for Joule heating-induced thermal expansion when a current flow passes through them. The piezoresistor is embedded in the base of the 'cold arm' flexure for monitoring the tip deflection and for performance characterization. This 'cold arm' is not a part of the electrical circuit, which further improves the heat power efficiency and the measurement accuracy. Optimization is achieved mainly through modification of the geometry as well as the fabrication process. The fabricated micro-electro-thermal actuator with an integrated sensor is intended for use as a scanning cantilever in atomic force microscope or as a sample holder to drive the moving object through arrays configuration.

  4. Cavity Ring Down and Thermal Lens Techniques Applied to Vibrational Spectroscopy of Gases and Liquids

    Science.gov (United States)

    Nyaupane, Parashu Ram

    Infrared (IR) and near-infrared (NIR) region gas temperature sensors have been used in the past because of its non-intrusive character and fast time response. In this dissertation cavity ring down (CRD) absorption of oxygen around the region 760 nm has been used to measure the temperature of flowing air in an open optical cavity. This sensor could be a convenient method for measuring the temperature at the input (cold air) and output (hot air) after cooling the blades of a gas turbine. The results could contribute to improvements in turbine blade cooling designs. Additionally, it could be helpful for high temperature measurement in harsh conditions like flames, boilers, and industrial pyrolysis ovens as well as remote sensing. We are interested in experiments that simulate the liquid methane and ethane lakes on Titan which is around the temperature of 94 K. Our specific goal is to quantify the solubility of unsaturated hydrocarbons in liquid ethane and methane. However, it is rather complicated to do so because of the low temperatures, low solubility and solvent effects. So, it is wise to do the experiments at higher temperature and test the suitability of the techniques. In these projects, we were trying to explore if our existing laboratory techniques were sensitive enough to obtain the solubility of unsaturated hydrocarbons in liquid ethane. First, we studied the thermal lens spectroscopy (TLS) of the (Deltav = 6) C-H overtone of benzene and naphthalene in hexane and CCl4 at room temperature.

  5. Data mining techniques in sensor networks summarization, interpolation and surveillance

    CERN Document Server

    Appice, Annalisa; Fumarola, Fabio; Malerba, Donato

    2013-01-01

    Sensor networks comprise of a number of sensors installed across a spatially distributed network, which gather information and periodically feed a central server with the measured data. The server monitors the data, issues possible alarms and computes fast aggregates. As data analysis requests may concern both present and past data, the server is forced to store the entire stream. But the limited storage capacity of a server may reduce the amount of data stored on the disk. One solution is to compute summaries of the data as it arrives, and to use these summaries to interpolate the real data.

  6. Characterization Techniques for a MEMS Electric-Field Sensor in Vacuum

    Science.gov (United States)

    2012-01-01

    nected so that the noise contributions of the transimpedance amplifier and the digitizer may be determined. The raw voltage data, after processing...of Vrms/rtHz. The noise may be seen in terms of the device trans- duction physics, signal conditioning ( transimpedance amp), and DAQ. (right) Field...Sensor using Thermal Actua- tors with Mechanically Amplified Response,” Solid-State Sensors, Actuators and Microsystems Confer- ence, 2007. TRANSDUCERS

  7. Generalized 1D photopyroelectric technique for optical and thermal characterization of liquids

    International Nuclear Information System (INIS)

    Balderas-López, J A

    2012-01-01

    The analytical solution for the one-dimensional heat diffusion problem for a three-layer system, in the Beer–Lambert model for light absorption, is used for the implementation of a photopyroelectric (PPE) methodology for thermal and optical characterization of pigments in liquid solution, even for those ones potentially harmful to the pyroelectric sensor, taking the liquid sample's thickness as the only variable. Exponential decay of the PPE amplitude followed by a constant PPE phase for solutions at low pigment concentration, and exponential decay of the PPE amplitude but a linear decrease of the PPE phase for the concentrated ones are theoretically shown, allowing measurements of the optical absorption coefficient (at the wavelength used for the analysis) and the thermal diffusivity for the liquid sample, respectively. This PPE methodology was tested by measuring the thermal diffusivity of a concentrated solution of methylene blue in distilled water and the optical absorption coefficient, at two wavelengths (658 and 785 nm), of water solutions of copper sulfate at various concentrations. These optical parameters were used for measuring the molar absorption coefficient of this last pigment in water solution at these two wavelengths. This last optical property was also measured using a commercial spectrometer, finding very good agreement with the corresponding ones using this PPE technique. (paper)

  8. Waste cell phone recycling by thermal plasma techniques

    Energy Technology Data Exchange (ETDEWEB)

    Inaba, T.; Kunimoto, N.; Abe, S. [Chuo Univ., Bunkyo-Ku, Tokyo (Japan). Dept. of Electrical, Electronics, and Communication Engineering; Li, O.L.; Chang, J.S.; Ruj, B. [McMaster Univ., Hamilton, ON (Canada). Faculty of Engineering

    2010-07-01

    Due to the cost-effective nature of wireless networks, the number of cell phones used around the world has increased significantly. However, a major problem of this technology is the generation of a great deal of complex electronics wastes, such as cell phones. The typical average life of a cell phone is around 2 years. Therefore, inexpensive recycling techniques must be developed for valuable resources such as real metals and plastics used in cell phones. Thermal plasma has been used for many different waste treatments since it has the capability to detoxify waste by-products. This paper presented a preliminary investigation for cell phone recycling by a thermal plasma technology. Recyclable resource material was identified by neutron activation analyses. Then, the cell phone waste was first crashed and treated by Ar twin torch plasmas to remove the majority of organic materials. The paper described the experimental apparatus and results. It was concluded that styrene (C{sub 8}H{sub 8}) and benzene (C{sub 6}H{sub 6}O) may be two major by-products in on-line by-products gas. The molecule becomes a much heavier by-product gas after cooling down. 6 refs., 6 figs.

  9. A new VFA sensor technique for anaerobic reactor systems

    DEFF Research Database (Denmark)

    Pind, Peter Frode; Angelidaki, Irini; Ahring, Birgitte Kiær

    2003-01-01

    , propionate, iso-/n-butyrate and iso-/n-valerate ranging from 0.1 to 50 mM (6-3000 mg). The measuring range could readily be expanded to more components and both lower and higher concentrations if desired. In addition to the new VFA sensor system, test results from development and testing of the in situ...

  10. Integrated fiber optical and thermal sensor for noninvasive monitoring of blood and human tissue

    Science.gov (United States)

    Saetchnikov, Vladimir A.; Tcherniavskaia, Elina A.; Schiffner, Gerhard

    2007-05-01

    A novel concept of noninvasive monitoring of human tissue and blood based on optical diffuse reflective spectroscopy combined with metabolic heat measurements has been under development. A compact integrated fiber optical and thermal sensor has been developed. The idea of the method was to evaluate by optical spectroscopy haemoglobin and derivative concentrations and supplement with data associated with the oxidative metabolism of glucose. Body heat generated by glucose oxidation is based on the balance of capillary glucose and oxygen supply to the cells. The variation in glucose concentration is followed also by a difference from a distance (or depth) of scattered through the body radiation. So, blood glucose can be estimated by measuring the body heat and the oxygen supply. The sensor pickup contains of halogen lamp and LEDs combined with fiber optical bundle to deliver optical radiation inside and through the patient body, optical and thermal detectors. Fiber optical probe allows diffuse scattering measurement down to a depth of 2.5 mm in the skin including vascular system, which contributes to the control of the body temperature. The sensor pickup measures thermal generation, heat balance, blood flow rate, haemoglobin and derivative concentrations, environmental conditions. Multivariate statistical analysis was applied to convert various signals from the sensor pickup into physicochemical variables. By comparing the values from the noninvasive measurement with the venous plasma result, analytical functions for patient were obtained. Cluster analysis of patient groups was used to simplify a calibration procedure. Clinical testing of developed sensor is being performed.

  11. Thermal-wave balancing flow sensor with low-drift power feedback

    NARCIS (Netherlands)

    Dijkstra, Marcel; Lammerink, Theodorus S.J.; Pjetri, O.; de Boer, Meint J.; Berenschot, Johan W.; Wiegerink, Remco J.; Elwenspoek, Michael Curt

    2014-01-01

    A control system using a low-drift power-feedback signal was implemented applying thermal waves, giving a sensor output independent of resistance drift and thermo-electric offset voltages on interface wires. Kelvin-contact sensing and power control is used on heater resistors, thereby inhibiting the

  12. RGB-D, Laser and Thermal Sensor Fusion for People following in a Mobile Robot

    Directory of Open Access Journals (Sweden)

    Loreto Susperregi

    2013-06-01

    Full Text Available Detecting and tracking people is a key capability for robots that operate in populated environments. In this paper, we used a multiple sensor fusion approach that combines three kinds of sensors in order to detect people using RGB-D vision, lasers and a thermal sensor mounted on a mobile platform. The Kinect sensor offers a rich data set at a significantly low cost, however, there are some limitations to its use in a mobile platform, mainly that the Kinect algorithms for people detection rely on images captured by a static camera. To cope with these limitations, this work is based on the combination of the Kinect and a Hokuyo laser and a thermopile array sensor. A real-time particle filter system merges the information provided by the sensors and calculates the position of the target, using probabilistic leg and thermal patterns, image features and optical flow to this end. Experimental results carried out with a mobile platform in a Science museum have shown that the combination of different sensory cues increases the reliability of the people following system.

  13. Thermal Annealing Effect on Structural, Morphological, and Sensor Performance of PANI-Ag-Fe Based Electrochemical E. coli Sensor for Environmental Monitoring

    Directory of Open Access Journals (Sweden)

    Norshafadzila Mohammad Naim

    2015-01-01

    Full Text Available PANI-Ag-Fe nanocomposite thin films based electrochemical E. coli sensor was developed with thermal annealing. PANI-Ag-Fe nanocomposite thin films were prepared by oxidative polymerization of aniline and the reduction process of Ag-Fe bimetallic compound with the presence of nitric acid and PVA. The films were deposited on glass substrate using spin-coating technique before they were annealed at 300°C. The films were characterized using XRD, UV-Vis spectroscopy, and FESEM to study the structural and morphological properties. The electrochemical sensor performance was conducted using I-V measurement electrochemical impedance spectroscopy (EIS. The sensitivity upon the presence of E. coli was measured in clean water and E. coli solution. From XRD analysis, the crystallite sizes were found to become larger for the samples after annealing. UV-Vis absorption bands for samples before and after annealing show maximum absorbance peaks at around 422 nm–424 nm and 426 nm–464 nm, respectively. FESEM images show the diameter size for nanospherical Ag-Fe alloy particles increases after annealing. The sensor performance of PANI-Ag-Fe nanocomposite thin films upon E. coli cells in liquid medium indicates the sensitivity increases after annealing.

  14. Stabilizing operation point technique based on the tunable distributed feedback laser for interferometric sensors

    Science.gov (United States)

    Mao, Xuefeng; Zhou, Xinlei; Yu, Qingxu

    2016-02-01

    We describe a stabilizing operation point technique based on the tunable Distributed Feedback (DFB) laser for quadrature demodulation of interferometric sensors. By introducing automatic lock quadrature point and wavelength periodically tuning compensation into an interferometric system, the operation point of interferometric system is stabilized when the system suffers various environmental perturbations. To demonstrate the feasibility of this stabilizing operation point technique, experiments have been performed using a tunable-DFB-laser as light source to interrogate an extrinsic Fabry-Perot interferometric vibration sensor and a diaphragm-based acoustic sensor. Experimental results show that good tracing of Q-point was effectively realized.

  15. ATTIRE (analytical tools for thermal infrared engineering): A sensor simulation and modeling package

    Science.gov (United States)

    Jaggi, S.

    1993-01-01

    The Advanced Sensor Development Laboratory (ASDL) at the Stennis Space Center develops, maintains and calibrates remote sensing instruments for the National Aeronautics & Space Administration (NASA). To perform system design trade-offs, analysis, and establish system parameters, ASDL has developed a software package for analytical simulation of sensor systems. This package called 'Analytical Tools for Thermal InfraRed Engineering' - ATTIRE, simulates the various components of a sensor system. The software allows each subsystem of the sensor to be analyzed independently for its performance. These performance parameters are then integrated to obtain system level information such as Signal-to-Noise Ratio (SNR), Noise Equivalent Radiance (NER), Noise Equivalent Temperature Difference (NETD) etc. This paper describes the uses of the package and the physics that were used to derive the performance parameters.

  16. Film-based Sensors with Piezoresistive Molecular Conductors as Active Components Strain Damage and Thermal Regeneration

    Directory of Open Access Journals (Sweden)

    Elena Laukhina

    2011-02-01

    Full Text Available The article is addressed to the development of flexible all-organic bi layer (BL film-based sensors being capable of measuring strain as a well-defined electrical signal in a wide range of elongations and temperature. The purpose was achieved by covering polycarbonate films with the polycrystalline layer of a high piezoresistive organic molecular conductor. To determine restrictions for sensor applications, the effect of monoaxial strain on the resistance and texture of the sensing layers of BL films was studied. The experiments have shown that the maximum strain before fracture is about 1 %. A thermal regeneration of the sensing layer of the BL film-based sensors that were damaged by cyclic load is also described. These sensors are able to take the place of conventional metal-based strain and pressure gages in low cost innovative controlling and monitoring technologies.

  17. Accelerometer Sensor Specifications to Predict Hydrocarbon Using Passive Seismic Technique

    Directory of Open Access Journals (Sweden)

    M. H. Md Khir

    2016-01-01

    Full Text Available The ambient seismic ground noise has been investigated in several surveys worldwide in the last 10 years to verify the correlation between observed seismic energy anomalies at the surface and the presence of hydrocarbon reserves beneath. This is due to the premise that anomalies provide information about the geology and potential presence of hydrocarbon. However a technology gap manifested in nonoptimal detection of seismic signals of interest is observed. This is due to the fact that available sensors are not designed on the basis of passive seismic signal attributes and mainly in terms of amplitude and bandwidth. This is because of that fact that passive seismic acquisition requires greater instrumentation sensitivity, noise immunity, and bandwidth, with active seismic acquisition, where vibratory or impulsive sources were utilized to receive reflections through geophones. Therefore, in the case of passive seismic acquisition, it is necessary to select the best monitoring equipment for its success or failure. Hence, concerning sensors performance, this paper highlights the technological gap and motivates developing dedicated sensors for optimal solution at lower frequencies. Thus, the improved passive seismic recording helps in oil and gas industry to perform better fracture mapping and identify more appropriate stratigraphy at low frequencies.

  18. High capacity fiber optic sensor networks using hybrid multiplexing techniques and their applications

    Science.gov (United States)

    Sun, Qizhen; Li, Xiaolei; Zhang, Manliang; Liu, Qi; Liu, Hai; Liu, Deming

    2013-12-01

    Fiber optic sensor network is the development trend of fiber senor technologies and industries. In this paper, I will discuss recent research progress on high capacity fiber sensor networks with hybrid multiplexing techniques and their applications in the fields of security monitoring, environment monitoring, Smart eHome, etc. Firstly, I will present the architecture of hybrid multiplexing sensor passive optical network (HSPON), and the key technologies for integrated access and intelligent management of massive fiber sensor units. Two typical hybrid WDM/TDM fiber sensor networks for perimeter intrusion monitor and cultural relics security are introduced. Secondly, we propose the concept of "Microstructure-Optical X Domin Refecltor (M-OXDR)" for fiber sensor network expansion. By fabricating smart micro-structures with the ability of multidimensional encoded and low insertion loss along the fiber, the fiber sensor network of simple structure and huge capacity more than one thousand could be achieved. Assisted by the WDM/TDM and WDM/FDM decoding methods respectively, we built the verification systems for long-haul and real-time temperature sensing. Finally, I will show the high capacity and flexible fiber sensor network with IPv6 protocol based hybrid fiber/wireless access. By developing the fiber optic sensor with embedded IPv6 protocol conversion module and IPv6 router, huge amounts of fiber optic sensor nodes can be uniquely addressed. Meanwhile, various sensing information could be integrated and accessed to the Next Generation Internet.

  19. A Thermal Technique of Fault Nucleation, Growth, and Slip

    Science.gov (United States)

    Garagash, D.; Germanovich, L. N.; Murdoch, L. C.; Martel, S. J.; Reches, Z.; Elsworth, D.; Onstott, T. C.

    2009-12-01

    Fractures and fluids influence virtually all mechanical processes in the crust, but many aspects of these processes remain poorly understood largely because of a lack of controlled field experiments at appropriate scale. We have developed an in-situ experimental approach to create carefully controlled faults at scale of ~10 meters using thermal techniques to modify in situ stresses to the point where the rock fails in shear. This approach extends experiments on fault nucleation and growth to length scales 2-3 orders of magnitude greater than are currently possible in the laboratory. The experiments could be done at depths where the modified in situ stresses are sufficient to drive faulting, obviating the need for unrealistically large loading frames. Such experiments require an access to large rock volumes in the deep subsurface in a controlled setting. The Deep Underground Science and Engineering Laboratory (DUSEL), which is a research facility planned to occupy the workings of the former Homestake gold mine in the northern Black Hills, South Dakota, presents an opportunity for accessing locations with vertical stresses as large as 60 MPa (down to 2400 m depth), which is sufficient to create faults. One of the most promising methods for manipulating stresses to create faults that we have evaluated involves drilling two parallel planar arrays of boreholes and circulating cold fluid (e.g., liquid nitrogen) to chill the region in the vicinity of the boreholes. Cooling a relatively small region around each borehole causes the rock to contract, reducing the normal compressive stress throughout much larger region between the arrays of boreholes. This scheme was evaluated using both scaling analysis and a finite element code. Our results show that if the boreholes are spaced by ~1 m, in several days to weeks, the normal compressive stress can be reduced by 10 MPa or more, and it is even possible to create net tension between the borehole arrays. According to the Mohr

  20. An Integrated Thermal Compensation System for MEMS Inertial Sensors

    Directory of Open Access Journals (Sweden)

    Sheng-Ren Chiu

    2014-03-01

    Full Text Available An active thermal compensation system for a low temperature-bias-drift (TBD MEMS-based gyroscope is proposed in this study. First, a micro-gyroscope is fabricated by a high-aspect-ratio silicon-on-glass (SOG process and vacuum packaged by glass frit bonding. Moreover, a drive/readout ASIC, implemented by the 0.25 µm 1P5M standard CMOS process, is designed and integrated with the gyroscope by directly wire bonding. Then, since the temperature effect is one of the critical issues in the high performance gyroscope applications, the temperature-dependent characteristics of the micro-gyroscope are discussed. Furthermore, to compensate the TBD of the micro-gyroscope, a thermal compensation system is proposed and integrated in the aforementioned ASIC to actively tune the parameters in the digital trimming mechanism, which is designed in the readout ASIC. Finally, some experimental results demonstrate that the TBD of the micro-gyroscope can be compensated effectively by the proposed compensation system.

  1. Orbital maneuvering vehicle thermal design and analysis techniques

    Science.gov (United States)

    Chapter, J.

    1986-01-01

    This paper describes the OMV thermal design that is required to maintain components within temperature limits for all mission phases. A key element in the OMV thermal design is the application of a motorized thermal shade assembly that is a replacement for the more conventional variable conductance heat pipes or louvers. The thermal shade assembly covers equipment module radiator areas, and based upon the radiator temperature input to onboard computer, opens and closes the shade, varying the effective radiator area. Thermal design verification thermal analyses results are presented. Selected thermal analyses methods, including several unique subroutines, are discussed. A representation of enclosure Script F equations, in matrix form, is also included. Personal computer application to the development of the OMV thermal design is summarized.

  2. X-ray computed microtomography characterizes the wound effect that causes sap flow underestimation by thermal dissipation sensors.

    Science.gov (United States)

    Marañón-Jiménez, S; Van den Bulcke, J; Piayda, A; Van Acker, J; Cuntz, M; Rebmann, C; Steppe, K

    2018-02-01

    Insertion of thermal dissipation (TD) sap flow sensors in living tree stems causes damage of the wood tissue, as is the case with other invasive methods. The subsequent wound formation is one of the main causes of underestimation of tree water-use measured by TD sensors. However, the specific alterations in wood anatomy in response to inserted sensors have not yet been characterized, and the linked dysfunctions in xylem conductance and sensor accuracy are still unknown. In this study, we investigate the anatomical mechanisms prompting sap flow underestimation and the dynamic process of wound formation. Successive sets of TD sensors were installed in the early, mid and end stage of the growing season in diffuse- and ring-porous trees, Fagus sylvatica (Linnaeus) and Quercus petraea ((Mattuschka) Lieblein), respectively. The trees were cut in autumn and additional sensors were installed in the cut stem segments as controls without wound formation. The wounded area and volume surrounding each sensor was then visually determined by X-ray computed microtomography (X-ray microCT). This technique allowed the characterization of vessel anatomical transformations such as tyloses formation, their spatial distribution and quantification of reduction in conductive area. MicroCT scans showed considerable formation of tyloses that reduced the conductive area of vessels surrounding the inserted TD probes, thus causing an underestimation in sap flux density (SFD) in both beech and oak. Discolored wood tissue was ellipsoidal, larger in the radial plane, more extensive in beech than in oak, and also for sensors installed for longer times. However, the severity of anatomical transformations did not always follow this pattern. Increased wound size with time, for example, did not result in larger SFD underestimation. This information helps us to better understand the mechanisms involved in wound effects with TD sensors and allows the provision of practical recommendations to reduce

  3. Thermal Spray Applications in Electronics and Sensors: Past, Present, and Future

    Science.gov (United States)

    Sampath, Sanjay

    2010-09-01

    Thermal spray has enjoyed unprecedented growth and has emerged as an innovative and multifaceted deposition technology. Thermal spray coatings are crucial to the enhanced utilization of various engineering systems. Industries, in recognition of thermal spray's versatility and economics, have introduced it into manufacturing environments. The majority of modern thermal spray applications are "passive" protective coatings, and they rarely perform an electronic function. The ability to consolidate dissimilar material multilayers without substrate thermal loading has long been considered a virtue for thick-film electronics. However, the complexity of understanding/controlling materials functions especially those resulting from rapid solidification and layered assemblage has stymied expansion into electronics. That situation is changing: enhancements in process/material science are allowing reconsideration for novel electronic/sensor devices. This review critically examines past efforts in terms of materials functionality from a device perspective, along with ongoing/future concepts addressing the aforementioned deficiencies. The analysis points to intriguing future possibilities for thermal spray technology in the world of thick-film sensors.

  4. Modeling and Experimental Study on Characterization of Micromachined Thermal Gas Inertial Sensors

    Directory of Open Access Journals (Sweden)

    Yan Su

    2010-09-01

    Full Text Available Micromachined thermal gas inertial sensors based on heat convection are novel devices that compared with conventional micromachined inertial sensors offer the advantages of simple structures, easy fabrication, high shock resistance and good reliability by virtue of using a gaseous medium instead of a mechanical proof mass as key moving and sensing elements. This paper presents an analytical modeling for a micromachined thermal gas gyroscope integrated with signal conditioning. A simplified spring-damping model is utilized to characterize the behavior of the sensor. The model relies on the use of the fluid mechanics and heat transfer fundamentals and is validated using experimental data obtained from a test-device and simulation. Furthermore, the nonideal issues of the sensor are addressed from both the theoretical and experimental points of view. The nonlinear behavior demonstrated in experimental measurements is analyzed based on the model. It is concluded that the sources of nonlinearity are mainly attributable to the variable stiffness of the sensor system and the structural asymmetry due to nonideal fabrication.

  5. Multidimensional inverse heat conduction problem: optimization of sensor locations and utilization of thermal-strain measurements

    International Nuclear Information System (INIS)

    Blanc, Gilles

    1996-01-01

    This work is devoted to the solution of the inverse multidimensional heat conduction problem. The first part is the determination of a methodology for determining the minimum number of sensors and the best sensor locations. The method is applied to a 20 problem but the extension to 30 problems is quite obvious. This methodology is based on the study of the rate of representation. This new concept allows to determine the quantity and the quality of the information obtain from the various sensors. The rate of representation is a useful tool for experimental design. lt can be determined very quickly by the transposed matrix method. This approach was validated with an experimental set-up. The second part is the development of a method that uses thermal strain measurement instead of temperature measurements to estimate the unknown thermal boundary conditions. We showed that this new sensor has two advantages in comparison with the classical temperature measurements: higher frequency can be estimated and smaller number of sensors can be used for 20 problems. The main weakness is, presently, the fact that the method can only be applied to beams. The results obtained from the numerical simulations were validated by the analysis of experimental data obtained on an experimental set-up especially designed and built for this study. (author) [fr

  6. Enhancing thermal reliability of fiber-optic sensors for bio-inspired applications at ultra-high temperatures

    International Nuclear Information System (INIS)

    Kang, Donghoon; Kim, Heon-Young; Kim, Dae-Hyun

    2014-01-01

    The rapid growth of bio-(inspired) sensors has led to an improvement in modern healthcare and human–robot systems in recent years. Higher levels of reliability and better flexibility, essential features of these sensors, are very much required in many application fields (e.g. applications at ultra-high temperatures). Fiber-optic sensors, and fiber Bragg grating (FBG) sensors in particular, are being widely studied as suitable sensors for improved structural health monitoring (SHM) due to their many merits. To enhance the thermal reliability of FBG sensors, thermal sensitivity, generally expressed as α f + ξ f and considered a constant, should be investigated more precisely. For this purpose, the governing equation of FBG sensors is modified using differential derivatives between the wavelength shift and the temperature change in this study. Through a thermal test ranging from RT to 900 °C, the thermal sensitivity of FBG sensors is successfully examined and this guarantees thermal reliability of FBG sensors at ultra-high temperatures. In detail, α f + ξ f has a non-linear dependence on temperature and varies from 6.0 × 10 −6  °C −1 (20 °C) to 10.6 × 10 −6  °C −1 (650 °C). Also, FBGs should be carefully used for applications at ultra-high temperatures due to signal disappearance near 900 °C. (paper)

  7. Enhancing thermal reliability of fiber-optic sensors for bio-inspired applications at ultra-high temperatures

    Science.gov (United States)

    Kang, Donghoon; Kim, Heon-Young; Kim, Dae-Hyun

    2014-07-01

    The rapid growth of bio-(inspired) sensors has led to an improvement in modern healthcare and human-robot systems in recent years. Higher levels of reliability and better flexibility, essential features of these sensors, are very much required in many application fields (e.g. applications at ultra-high temperatures). Fiber-optic sensors, and fiber Bragg grating (FBG) sensors in particular, are being widely studied as suitable sensors for improved structural health monitoring (SHM) due to their many merits. To enhance the thermal reliability of FBG sensors, thermal sensitivity, generally expressed as αf + ξf and considered a constant, should be investigated more precisely. For this purpose, the governing equation of FBG sensors is modified using differential derivatives between the wavelength shift and the temperature change in this study. Through a thermal test ranging from RT to 900 °C, the thermal sensitivity of FBG sensors is successfully examined and this guarantees thermal reliability of FBG sensors at ultra-high temperatures. In detail, αf + ξf has a non-linear dependence on temperature and varies from 6.0 × 10-6 °C-1 (20 °C) to 10.6 × 10-6 °C-1 (650 °C). Also, FBGs should be carefully used for applications at ultra-high temperatures due to signal disappearance near 900 °C.

  8. Thermal Conductivity of EB-PVD Thermal Barrier Coatings Evaluated by a Steady-State Laser Heat Flux Technique

    Science.gov (United States)

    Zhu, Dongming; Miller, Robert A.; Nagaraj, Ben A.; Bruce, Robert W.

    2000-01-01

    The thermal conductivity of electron beam-physical vapor deposited (EB-PVD) Zr02-8wt%Y2O3 thermal barrier coatings was determined by a steady-state heat flux laser technique. Thermal conductivity change kinetics of the EB-PVD ceramic coatings were also obtained in real time, at high temperatures, under the laser high heat flux, long term test conditions. The thermal conductivity increase due to micro-pore sintering and the decrease due to coating micro-delaminations in the EB-PVD coatings were evaluated for grooved and non-grooved EB-PVD coating systems under isothermal and thermal cycling conditions. The coating failure modes under the high heat flux test conditions were also investigated. The test technique provides a viable means for obtaining coating thermal conductivity data for use in design, development, and life prediction for engine applications.

  9. Spin wave differential circuit for realization of thermally stable magnonic sensors

    Energy Technology Data Exchange (ETDEWEB)

    Goto, Taichi, E-mail: goto@ee.tut.ac.jp; Kanazawa, Naoki; Buyandalai, Altansargai; Takagi, Hiroyuki; Nakamura, Yuichi; Inoue, Mitsuteru [Department of Electrical and Electronic Information Engineering, Toyohashi University of Technology, 1-1 Hibari-Ga-Oka, Tempaku, Toyohashi, Aichi 441-8580 (Japan); Okajima, Shingo; Hasegawa, Takashi [Murata Manufacturing Co., Ltd., Kyoto 617-8555 (Japan); Granovsky, Alexander B. [Faculty of Physics, Moscow State University, Leninskie Gory, Moscow 119992 (Russian Federation); Sekiguchi, Koji [Department of Physics, Keio University, Yokohama 223-8522 (Japan); JST-PRESTO, Kawaguchi, Saitama 332-0012 (Japan); Ross, Caroline A. [Department of Materials Science and Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139 (United States)

    2015-03-30

    A magnetic-field sensor with a high sensitivity of 38 pT/Hz was demonstrated. By utilizing a spin-wave differential circuit (SWDC) using two yttrium iron garnet (YIG) films, the temperature sensitivity was suppressed, and the thermal stability of the phase of the spin waves was −0.0095° K{sup −1}, which is three orders of magnitude better than a simple YIG-based sensor, ∼20° K{sup −1}. The SWDC architecture opens the way to design YIG-based magnonic devices.

  10. Spin wave differential circuit for realization of thermally stable magnonic sensors

    International Nuclear Information System (INIS)

    Goto, Taichi; Kanazawa, Naoki; Buyandalai, Altansargai; Takagi, Hiroyuki; Nakamura, Yuichi; Inoue, Mitsuteru; Okajima, Shingo; Hasegawa, Takashi; Granovsky, Alexander B.; Sekiguchi, Koji; Ross, Caroline A.

    2015-01-01

    A magnetic-field sensor with a high sensitivity of 38 pT/Hz was demonstrated. By utilizing a spin-wave differential circuit (SWDC) using two yttrium iron garnet (YIG) films, the temperature sensitivity was suppressed, and the thermal stability of the phase of the spin waves was −0.0095° K −1 , which is three orders of magnitude better than a simple YIG-based sensor, ∼20° K −1 . The SWDC architecture opens the way to design YIG-based magnonic devices

  11. Fabrication and thermal oxidation of ZnO nano fibers prepared via electro spinning technique

    International Nuclear Information System (INIS)

    Baek, Jeongha; Park, Juyun; Kim, Don; Kang, Yongcheol; Koh, Sungwi; Kang, Jisoo

    2012-01-01

    Materials on the scale of nano scale have widely been used as research topics because of their interesting characteristics and aspects they bring into the field. Out of the many metal oxides, zinc oxide (ZnO) was chosen to be fabricated as nano fibers using the electro spinning method for potential uses of solar cells and sensors. After ZnO nano fibers were obtained, calcination temperature effects on the ZnO nano fibers were studied and reported here. The results of scanning electron microscopy (SEM) revealed that the aggregation of the ZnO nano fibers progressed by calcination. X-ray diffraction (XRD) study showed the hcp ZnO structure was enhanced by calcination at 873 and 1173 K. Transmission electron microscopy (TEM) confirmed the crystallinity of the calcined ZnO nano fibers. X-ray photoelectron spectroscopy (XPS) verified the thermal oxidation of Zn species by calcination in the nano fibers. These techniques have helped US deduce the facts that the diameter of ZnO increases as the calcination temperature was raised; the process of calcination affects the crystallinity of ZnO nano fibers, and the thermal oxidation of Zn species was observed as the calcination temperature was raised

  12. Multi-parameter fibre Bragg grating sensor-array for thermal vacuum cycling test

    Science.gov (United States)

    Cheng, L.; Ahlers, B.; Toet, P.; Casarosa, G.; Appolloni, M.

    2017-11-01

    Fibre Bragg Grating (FBG) sensor systems based on optical fibres are gaining interest in space applications. Studies on Structural Health Monitoring (SHM) of the reusable launchers using FBG sensors have been carried out in the Future European Space Transportation Investigations Programme (FESTIP). Increasing investment in the development on FBG sensor applications is foreseen for the Future Launchers Preparatory Programme (FLPP). TNO has performed different SHM measurements with FBGs including on the VEGA interstage [1, 2] in 2006. Within the current project, a multi-parameter FBG sensor array demonstrator system for temperature and strain measurements is designed, fabricated and tested under ambient as well as Thermal Vacuum (TV) conditions in a TV chamber of the European Space Agency (ESA), ESTEC site. The aim is the development of a multi-parameters measuring system based on FBG technology for space applications. During the TV tests of a Space Craft (S/C) or its subsystems, thermal measurements, as well as strain measurements are needed by the engineers in order to verify their prediction and to validate their models. Because of the dimensions of the test specimen and the accuracy requested to the measurement, a large number of observation/measuring points are needed. Conventional sensor systems require a complex routing of the cables connecting the sensors to their acquisition unit. This will add extra weight to the construction under test. FBG sensors are potentially light-weight and can easily be multiplexed in an array configuration. The different tasks comply of a demonstrator system design; its component selection, procurement, manufacturing and finally its assembly. The temperature FBG sensor is calibrated in a dedicated laboratory setup down to liquid nitrogen (LN2) temperature at TNO. A temperature-wavelength calibration curve is generated. After a test programme definition a setup in thermal vacuum is realised at ESA premises including a mechanical

  13. A review of spectrally coded multiplexing techniques for fibre grating sensor systems

    International Nuclear Information System (INIS)

    Childs, Paul; Wong, Allan C L; Yan, Binbin; Li, Mo; Peng, Gang-Ding

    2010-01-01

    We review recent work and progress on spectrally coded multiplexing (SCM). SCM is a generic multiplexing technique that provides more efficient data usage, additional flexibility and greater channel capability for fibre and fibre grating based sensor systems. We show a few examples of newly developed SCM techniques based on specially designed fibre gratings

  14. SRAM Design for Wireless Sensor Networks Energy Efficient and Variability Resilient Techniques

    CERN Document Server

    Sharma, Vibhu; Dehaene, Wim

    2013-01-01

    This book features various, ultra low energy, variability resilient SRAM circuit design techniques for wireless sensor network applications. Conventional SRAM design targets area efficiency and high performance at the increased cost of energy consumption, making it unsuitable for computation-intensive sensor node applications.  This book, therefore, guides the reader through different techniques at the circuit level for reducing   energy consumption and increasing the variability resilience. It includes a detailed review of the most efficient circuit design techniques and trade-offs, introduces new memory architecture techniques, sense amplifier circuits and voltage optimization methods for reducing the impact of variability for the advanced technology nodes.    Discusses fundamentals of energy reduction for SRAM circuits and applies them to energy limitation challenges associated with wireless sensor  nodes; Explains impact of variability resilience in reducing the energy consumption; Describes various...

  15. SMA bellows as reversible thermal sensors/actuators

    International Nuclear Information System (INIS)

    Damanpack, A R; Bodaghi, M; Liao, W H

    2015-01-01

    In this paper, the feasibility of reversible bellows made of shape memory alloys (SMAs) in sensory and actuated applications to transfer pressure and/or temperature into a linear motion is investigated. An analytical three-dimensional model is developed to simulate key features of SMAs including martensitic transformation, reorientation of martensite variants, the shape memory effect, and pseudo-elasticity. Axisymmetric two-dimensional theory of thermo-inelasticity based on the non-linear Green–Lagrange strain tensor is employed to derive the equilibrium equations. A finite element method along with an iterative incremental elastic-predictor–inelastic-corrector procedure is developed to solve the governing equations with both material and geometrical non-linearities. The feasibility of reversible SMA bellows in transferring pressure and/or temperature into a linear motion is numerically demonstrated. In this respect, the effects of geometric parameters, magnitude of thermo-mechanical loadings and end conditions on the performances of SMA bellows are evaluated and discussed in depth. This study provides pertinent results toward an efficient and reliable design of reversible thermally-driven SMA bellows. (paper)

  16. Effect of heater geometry and cavity volume on the sensitivity of a thermal convection-based tilt sensor

    Science.gov (United States)

    Han, Maeum; Keon Kim, Jae; Kong, Seong Ho; Kang, Shin-Won; Jung, Daewoong

    2018-06-01

    This paper reports a micro-electro-mechanical-system (MEMS)-based tilt sensor using air medium. Since the working mechanism of the sensor is the thermal convection in a sealed chamber, structural parameters that can affect thermal convection must be considered to optimize the performance of the sensor. This paper presents the experimental results that were conducted by optimizing several parameters such as the heater geometry, input power and cavity volume. We observed that an increase in the heating power and cavity volume can improve the sensitivity, and heater geometry plays important role in performance of the sensor.

  17. Fabrication and Characterization of a Micro Methanol Sensor Using the CMOS-MEMS Technique

    Directory of Open Access Journals (Sweden)

    Chien-Fu Fong

    2015-10-01

    Full Text Available A methanol microsensor integrated with a micro heater manufactured using the complementary metal oxide semiconductor (CMOS-microelectromechanical system (MEMS technique was presented. The sensor has a capability of detecting low concentration methanol gas. Structure of the sensor is composed of interdigitated electrodes, a sensitive film and a heater. The heater located under the interdigitated electrodes is utilized to provide a working temperature to the sensitive film. The sensitive film prepared by the sol-gel method is tin dioxide doped cadmium sulfide, which is deposited on the interdigitated electrodes. To obtain the suspended structure and deposit the sensitive film, the sensor needs a post-CMOS process to etch the sacrificial silicon dioxide layer and silicon substrate. The methanol senor is a resistive type. A readout circuit converts the resistance variation of the sensor into the output voltage. The experimental results show that the methanol sensor has a sensitivity of 0.18 V/ppm.

  18. Hysteresis compensation technique applied to polymer optical fiber curvature sensor for lower limb exoskeletons

    Science.gov (United States)

    Gomes Leal-Junior, Arnaldo; Frizera-Neto, Anselmo; José Pontes, Maria; Rodrigues Botelho, Thomaz

    2017-12-01

    Polymer optical fiber (POF) curvature sensors present some advantages over conventional techniques for angle measurements, such as their light weight, compactness and immunity to electromagnetic fields. However, high hysteresis can occur in POF curvature sensors due to the polymer viscoelastic response. In order to overcome this limitation, this paper shows how the hysteresis sensor can be compensated by a calibration equation relating the measured output signal to the sensor’s angular velocity. The proposed method is validated using an exoskeleton with an active joint on the knee for flexion and extension rehabilitation exercises. The results show a decrease in sensor hysteresis and a decrease by more than two times in the error between the POF sensor and the potentiometer, which is employed for the angle measurement of the exoskeleton knee joint.

  19. Fabrication and Characterization of a Micro Methanol Sensor Using the CMOS-MEMS Technique.

    Science.gov (United States)

    Fong, Chien-Fu; Dai, Ching-Liang; Wu, Chyan-Chyi

    2015-10-23

    A methanol microsensor integrated with a micro heater manufactured using the complementary metal oxide semiconductor (CMOS)-microelectromechanical system (MEMS) technique was presented. The sensor has a capability of detecting low concentration methanol gas. Structure of the sensor is composed of interdigitated electrodes, a sensitive film and a heater. The heater located under the interdigitated electrodes is utilized to provide a working temperature to the sensitive film. The sensitive film prepared by the sol-gel method is tin dioxide doped cadmium sulfide, which is deposited on the interdigitated electrodes. To obtain the suspended structure and deposit the sensitive film, the sensor needs a post-CMOS process to etch the sacrificial silicon dioxide layer and silicon substrate. The methanol senor is a resistive type. A readout circuit converts the resistance variation of the sensor into the output voltage. The experimental results show that the methanol sensor has a sensitivity of 0.18 V/ppm.

  20. Local thermal conductivity of polycrystalline AlN ceramics measured by scanning thermal microscopy and complementary scanning electron microscopy techniques

    International Nuclear Information System (INIS)

    Zhang Yue-Fei; Wang Li; Wei Bin; Ji Yuan; Han Xiao-Dong; Zhang Ze; Heiderhoff, R.; Geinzer, A. K.; Balk, L. J.

    2012-01-01

    The local thermal conductivity of polycrystalline aluminum nitride (AlN) ceramics is measured and imaged by using a scanning thermal microscope (SThM) and complementary scanning electron microscope (SEM) based techniques at room temperature. The quantitative thermal conductivity for the AlN sample is gained by using a SThM with a spatial resolution of sub-micrometer scale through using the 3ω method. A thermal conductivity of 308 W/m·K within grains corresponding to that of high-purity single crystal AlN is obtained. The slight differences in thermal conduction between the adjacent grains are found to result from crystallographic misorientations, as demonstrated in the electron backscattered diffraction. A much lower thermal conductivity at the grain boundary is due to impurities and defects enriched in these sites, as indicated by energy dispersive X-ray spectroscopy. (condensed matter: structural, mechanical, and thermal properties)

  1. Parameter Estimation of the Thermal Network Model of a Machine Tool Spindle by Self-made Bluetooth Temperature Sensor Module

    Directory of Open Access Journals (Sweden)

    Yuan-Chieh Lo

    2018-02-01

    Full Text Available Thermal characteristic analysis is essential for machine tool spindles because sudden failures may occur due to unexpected thermal issue. This article presents a lumped-parameter Thermal Network Model (TNM and its parameter estimation scheme, including hardware and software, in order to characterize both the steady-state and transient thermal behavior of machine tool spindles. For the hardware, the authors develop a Bluetooth Temperature Sensor Module (BTSM which accompanying with three types of temperature-sensing probes (magnetic, screw, and probe. Its specification, through experimental test, achieves to the precision ±(0.1 + 0.0029|t| °C, resolution 0.00489 °C, power consumption 7 mW, and size Ø40 mm × 27 mm. For the software, the heat transfer characteristics of the machine tool spindle correlative to rotating speed are derived based on the theory of heat transfer and empirical formula. The predictive TNM of spindles was developed by grey-box estimation and experimental results. Even under such complicated operating conditions as various speeds and different initial conditions, the experiments validate that the present modeling methodology provides a robust and reliable tool for the temperature prediction with normalized mean square error of 99.5% agreement, and the present approach is transferable to the other spindles with a similar structure. For realizing the edge computing in smart manufacturing, a reduced-order TNM is constructed by Model Order Reduction (MOR technique and implemented into the real-time embedded system.

  2. Optical fiber biocompatible sensors for monitoring selective treatment of tumors via thermal ablation

    Science.gov (United States)

    Tosi, Daniele; Poeggel, Sven; Dinesh, Duraibabu B.; Macchi, Edoardo G.; Gallati, Mario; Braschi, Giovanni; Leen, Gabriel; Lewis, Elfed

    2015-09-01

    Thermal ablation (TA) is an interventional procedure for selective treatment of tumors, that results in low-invasive outpatient care. The lack of real-time control of TA is one of its main weaknesses. Miniature and biocompatible optical fiber sensors are applied to achieve a dense, multi-parameter monitoring, that can substantially improve the control of TA. Ex vivo measurements are reported performed on porcine liver tissue, to reproduce radiofrequency ablation of hepatocellular carcinoma. Our measurement campaign has a two-fold focus: (1) dual pressure-temperature measurement with a single probe; (2) distributed thermal measurement to estimate point-by-point cells mortality.

  3. Thermal properties of calorimeters with Ti/Au transition-edge sensors on silicon nitride membranes

    International Nuclear Information System (INIS)

    Ukibe, M.; Tanaka, K.; Koyanagi, M.; Morooka, T.; Pressler, H.; Ohkubo, M.; Kobayashi, N.

    2000-01-01

    We are developing X-ray microcalorimeters employing superconducting-transition-edge sensors (TESs) for relatively high operation-temperatures of an 3 He cryostat. The TESs are proximity bilayers of Ti and Au. An important thermal parameters, the thermal conductance G, of the microcalorimeters on SiN x membranes was evaluated by a simple method using R-T curves at different bias currents. It has been shown that the G value can be controlled by altering the membrane thickness and size

  4. Real time interrogation technique for fiber Bragg grating enhanced fiber loop ringdown sensors array.

    Science.gov (United States)

    Zhang, Yunlong; Li, Ruoming; Shi, Yuechun; Zhang, Jintao; Chen, Xiangfei; Liu, Shengchun

    2015-06-01

    A novel fiber Bragg grating aided fiber loop ringdown (FLRD) sensor array and the wavelength-time multiplexing based interrogation technique for the FLRD sensors array are proposed. The interrogation frequency of the system is formulated and the interrelationships among the parameters of the system are analyzed. To validate the performance of the proposed system, a five elements array is experimentally demonstrated, and the system shows the capability of real time monitoring every FLRD element with interrogation frequency of 125.5 Hz.

  5. Fiber Strain Measurement for Wide Region Quasidistributed Sensing by Optical Correlation Sensor with Region Separation Techniques

    Directory of Open Access Journals (Sweden)

    Xunjian Xu

    2010-01-01

    Full Text Available The useful application of optical pulse correlation sensor for wide region quasidistributed fiber strain measurement is investigated. Using region separation techniques of wavelength multiplexing with FBGs and time multiplexing with intensity partial reflectors, the sensor measures the correlations between reference pulses and monitoring pulses from several cascadable selected sensing regions. This novel sensing system can select the regions and obtain the distributed strain information in any desired sensing region.

  6. Probe beam deflection technique as acoustic emission directionality sensor with photoacoustic emission source.

    Science.gov (United States)

    Barnes, Ronald A; Maswadi, Saher; Glickman, Randolph; Shadaram, Mehdi

    2014-01-20

    The goal of this paper is to demonstrate the unique capability of measuring the vector or angular information of propagating acoustic waves using an optical sensor. Acoustic waves were generated using photoacoustic interaction and detected by the probe beam deflection technique. Experiments and simulations were performed to study the interaction of acoustic emissions with an optical sensor in a coupling medium. The simulated results predict the probe beam and wavefront interaction and produced simulated signals that are verified by experiment.

  7. Modeling of an Aged Porous Silicon Humidity Sensor Using ANN Technique

    Directory of Open Access Journals (Sweden)

    Tarikul ISLAM

    2006-10-01

    Full Text Available Porous silicon (PS sensor based on capacitive technique used for measuring relative humidity has the advantages of low cost, ease of fabrication with controlled structure and CMOS compatibility. But the response of the sensor is nonlinear function of humidity and suffers from errors due to aging and stability. One adaptive linear (ADALINE ANN model has been developed to model the behavior of the sensor with a view to estimate these errors and compensate them. The response of the sensor is represented by third order polynomial basis function whose coefficients are determined by the ANN technique. The drift in sensor output due to aging of PS layer is also modeled by adapting the weights of the polynomial function. ANN based modeling is found to be more suitable than conventional physical modeling of PS humidity sensor in changing environment and drift due to aging. It helps online estimation of nonlinearity as well as monitoring of the fault of the PS humidity sensor using the coefficients of the model.

  8. Wavelength dependent pH optical sensor using the layer-by-layer technique

    OpenAIRE

    Raoufi, N.; Surre, F.; Sun, T.; Rajarajan, M.; Grattan, K. T. V.

    2012-01-01

    In this work, the design and characteristics of a wavelength-dependent pH optical sensor have been studied. To create the sensor itself, brilliant yellow (BY) as a pH indicator and poly (allylamine hydrochloride) [PAH] as a cross-linker have been deposited on the end of a bare silica core of an optical fibre by use of a ‘layer-by-layer’ technique. In the experiments carried out to characterize the sensor, it was observed that the value of pKa (the dissociation constant) of the thin film is de...

  9. Thermal and chemical treatment of polymer optical fiber Bragg grating sensors for enhanced mechanical sensitivity

    DEFF Research Database (Denmark)

    Pospori, Andreas; Marques, C. A. F.; Saez-Rodriguez, D.

    2017-01-01

    An investigation of the thermal annealing effects on the strain, stress, and force sensitivities of polymer optical fiber Bragg grating sensors is performed. We demonstrate for the first time that the fiber annealing can enhance both stress and force sensitivities of Bragg grating sensors......, with the possible cause being the molecular relaxation of the polymer when fiber is raised above the β-transition temperature. A simple, cost-effective, but well controlled method for fiber annealing is also presented in this work. In addition, the effects of chemical etching on the strain, stress, and force...... sensitivities have been investigated. Results show that fiber etching too can increase the force sensitivity, and it can also affect the strain and stress sensitivities of the Bragg grating sensors....

  10. Thermal and chemical treatment of polymer optical fiber Bragg grating sensors for enhanced mechanical sensitivity

    Science.gov (United States)

    Pospori, A.; Marques, C. A. F.; Sáez-Rodríguez, D.; Nielsen, K.; Bang, O.; Webb, D. J.

    2017-07-01

    An investigation of the thermal annealing effects on the strain, stress, and force sensitivities of polymer optical fiber Bragg grating sensors is performed. We demonstrate for the first time that the fiber annealing can enhance both stress and force sensitivities of Bragg grating sensors, with the possible cause being the molecular relaxation of the polymer when fiber is raised above the β -transition temperature. A simple, cost-effective, but well controlled method for fiber annealing is also presented in this work. In addition, the effects of chemical etching on the strain, stress, and force sensitivities have been investigated. Results show that fiber etching too can increase the force sensitivity, and it can also affect the strain and stress sensitivities of the Bragg grating sensors.

  11. Optical Sensor of Thermal Gas Flow Based on Fiber Bragg Grating

    Directory of Open Access Journals (Sweden)

    Xu Jiang

    2017-02-01

    Full Text Available This paper aims at solving the problem of explosion proof in measurement of thermal gas flow using electronic sensor by presenting a new type of flow sensor by optical fiber heating. A measuring unit based on fiber Bragg grating (FBG for fluid temperature and a unit for heat dissipation are designed to replace the traditional electronic sensors. The light in C band from the amplified spontaneous emission (ASE light source is split, with one part used to heat the absorbing coating and the other part used in the signal processing unit. In the heating unit, an absorbing coating is introduced to replace the traditional resistance heating module to minimize the risk of explosion. The measurement results demonstrate a fine consistency between the flow and temperature difference in simulation. The method to enhance the measurement resolution of flow is also discussed.

  12. An Universal packaging technique for low-drift implantable pressure sensors.

    Science.gov (United States)

    Kim, Albert; Powell, Charles R; Ziaie, Babak

    2016-04-01

    Monitoring bodily pressures provide valuable diagnostic and prognostic information. In particular, long-term measurement through implantable sensors is highly desirable in situations where percutaneous access can be complicated or dangerous (e.g., intracranial pressure in hydrocephalic patients). In spite of decades of progress in the fabrication of miniature solid-state pressure sensors, sensor drift has so far severely limited their application in implantable systems. In this paper, we report on a universal packaging technique for reducing the sensor drift. The described method isolates the pressure sensor from a major source of drift, i.e., contact with the aqueous surrounding environment, by encasing the sensor in a silicone-filled medical-grade polyurethane balloon. In-vitro soak tests for 100 days using commercial micromachined piezoresistive pressure sensors demonstrate a stable operation with the output remaining within 1.8 cmH2O (1.3 mmHg) of a reference pressure transducer. Under similar test conditions, a non-isolated sensor fluctuates between 10 and 20 cmH2O (7.4-14.7 mmHg) of the reference, without ever settling to a stable operation regime. Implantation in Ossabow pigs demonstrate the robustness of the package and its in-vivo efficacy in reducing the baseline drift.

  13. Application of Advanced Particle Swarm Optimization Techniques to Wind-thermal Coordination

    DEFF Research Database (Denmark)

    Singh, Sri Niwas; Østergaard, Jacob; Yadagiri, J.

    2009-01-01

    wind-thermal coordination algorithm is necessary to determine the optimal proportion of wind and thermal generator capacity that can be integrated into the system. In this paper, four versions of Particle Swarm Optimization (PSO) techniques are proposed for solving wind-thermal coordination problem...

  14. Time response measurements of pressure sensors using pink noise technique

    International Nuclear Information System (INIS)

    Pereira, Iraci Martinez; Santos, Roberto Carlos dos

    2009-01-01

    This work presents an experimental setup for Pink Noise method application on pressure transmitters' response times. The Pink Noise method consists on injecting artificial pressure noise into the pressure transmitter. The artificial pressure noise is generated using a current-to-pressure (I-to-P) converter, which is driven by a random noise signal generator. The output pressure transmitter noise is then analyzed using conventional Noise Analysis Technique. Noise signals may be interpreted using spectral techniques or empirical time series models. The frequency domain method consists of evaluating the Power Spectral Density (PSD) function. The information needed for time constant estimation can be obtained by fitting an all-pole transfer function to this power spectral density. (author)

  15. Sensor Fusion Techniques for Phased-Array Eddy Current and Phased-Array Ultrasound Data

    Energy Technology Data Exchange (ETDEWEB)

    Arrowood, Lloyd F. [Y-12 National Security Complex, Oak Ridge, TN (United States)

    2018-03-15

    Sensor (or Data) fusion is the process of integrating multiple data sources to produce more consistent, accurate and comprehensive information than is provided by a single data source. Sensor fusion may also be used to combine multiple signals from a single modality to improve the performance of a particular inspection technique. Industrial nondestructive testing may utilize multiple sensors to acquire inspection data depending upon the object under inspection and the anticipated types of defects that can be identified. Sensor fusion can be performed at various levels of signal abstraction with each having its strengths and weaknesses. A multimodal data fusion strategy first proposed by Heideklang and Shokouhi that combines spatially scattered detection locations to improve detection performance of surface-breaking and near-surface cracks in ferromagnetic metals is shown using a surface inspection example and is then extended for volumetric inspections. Utilizing data acquired from an Olympus Omniscan MX2 from both phased array eddy current and ultrasound probes on test phantoms, single and multilevel fusion techniques are employed to integrate signals from the two modalities. Preliminary results demonstrate how confidence in defect identification and interpretation benefit from sensor fusion techniques. Lastly, techniques for integrating data into radiographic and volumetric imagery from computed tomography are described and results are presented.

  16. Spatially distributed damage detection in CMC thermal protection materials using thin-film piezoelectric sensors

    Science.gov (United States)

    Kuhr, Samuel J.; Blackshire, James L.; Na, Jeong K.

    2009-03-01

    Thermal protection systems (TPS) of aerospace vehicles are subjected to impacts during in-flight use and vehicle refurbishment. The damage resulting from such impacts can produce localized regions that are unable to resist extreme temperatures. Therefore it is essential to have a reliable method to detect, locate, and quantify the damage occurring from such impacts. The objective of this research is to demonstrate a capability that could lead to detecting, locating and quantifying impact events for ceramic matrix composite (CMC) wrapped tile TPS via sensors embedded in the TPS material. Previous research had shown a correlation between impact energies, material damage state, and polyvinylidene fluoride (PVDF) sensor response for impact energies between 0.07 - 1.00 Joules, where impact events were located directly over the sensor positions1. In this effort, the effectiveness of a sensor array is evaluated for detecting and locating low energy impacts on a CMC wrapped TPS. The sensor array, which is adhered to the internal surface of the TPS tile, is used to detect low energy impact events that occur at different locations. The analysis includes an evaluation of signal amplitude levels, time-of-flight measurements, and signal frequency content. Multiple impacts are performed at each location to study the repeatability of each measurement.

  17. Long fiber Bragg grating sensor interrogation using discrete-time microwave photonic filtering techniques.

    Science.gov (United States)

    Ricchiuti, Amelia Lavinia; Barrera, David; Sales, Salvador; Thevenaz, Luc; Capmany, José

    2013-11-18

    A novel technique for interrogating photonic sensors based on long fiber Bragg gratings (FBGs) is presented and experimentally demonstrated, dedicated to detect the presence and the precise location of several spot events. The principle of operation is based on a technique used to analyze microwave photonics (MWP) filters. The long FBGs are used as quasi-distributed sensors. Several hot-spots can be detected along the FBG with a spatial accuracy under 0.5 mm using a modulator and a photo-detector (PD) with a modest bandwidth of less than 1 GHz. The proposed interrogation system is intrinsically robust against environmental changes.

  18. Crack monitoring method based on Cu coating sensor and electrical potential technique for metal structure

    Directory of Open Access Journals (Sweden)

    Hou Bo

    2015-06-01

    Full Text Available Advanced crack monitoring technique is the cornerstone of aircraft structural health monitoring. To achieve real-time crack monitoring of aircraft metal structures in the course of service, a new crack monitoring method is proposed based on Cu coating sensor and electrical potential difference principle. Firstly, insulation treatment process was used to prepare a dielectric layer on structural substrate, such as an anodizing layer on 2A12-T4 aluminum alloy substrate, and then a Cu coating crack monitoring sensor was deposited on the structure fatigue critical parts by pulsed bias arc ion plating technology. Secondly, the damage consistency of the Cu coating sensor and 2A12-T4 aluminum alloy substrate was investigated by static tensile experiment and fatigue test. The results show that strain values of the coating sensor and the 2A12-T4 aluminum alloy substrate measured by strain gauges are highly coincident in static tensile experiment and the sensor has excellent fatigue damage consistency with the substrate. Thirdly, the fatigue performance discrepancy between samples with the coating sensor and original samples was investigated. The result shows that there is no obvious negative influence on the fatigue performance of the 2A12-T4 aluminum alloy after preparing the Cu coating sensor on its surface. Finally, crack monitoring experiment was carried out with the Cu coating sensor. The experimental results indicate that the sensor is sensitive to crack, and crack origination and propagation can be monitored effectively through analyzing the change of electrical potential values of the coating sensor.

  19. Autonomous pedestrian localization technique using CMOS camera sensors

    Science.gov (United States)

    Chun, Chanwoo

    2014-09-01

    We present a pedestrian localization technique that does not need infrastructure. The proposed angle-only measurement method needs specially manufactured shoes. Each shoe has two CMOS cameras and two markers such as LEDs attached on the inward side. The line of sight (LOS) angles towards the two markers on the forward shoe are measured using the two cameras on the other rear shoe. Our simulation results shows that a pedestrian walking down in a shopping mall wearing this device can be accurately guided to the front of a destination store located 100m away, if the floor plan of the mall is available.

  20. Simulating Physiological Response with a Passive Sensor Manikin and an Adaptive Thermal Manikin to Predict Thermal Sensation and Comfort

    Energy Technology Data Exchange (ETDEWEB)

    Rugh, John P [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Chaney, Larry [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Hepokoski, Mark [ThermoAnalytics Inc.; Curran, Allen [ThermoAnalytics Inc.; Burke, Richard [Measurement Technology NW; Maranville, Clay [Ford Motor Company

    2015-04-14

    Reliable assessment of occupant thermal comfort can be difficult to obtain within automotive environments, especially under transient and asymmetric heating and cooling scenarios. Evaluation of HVAC system performance in terms of comfort commonly requires human subject testing, which may involve multiple repetitions, as well as multiple test subjects. Instrumentation (typically comprised of an array of temperature sensors) is usually only sparsely applied across the human body, significantly reducing the spatial resolution of available test data. Further, since comfort is highly subjective in nature, a single test protocol can yield a wide variation in results which can only be overcome by increasing the number of test replications and subjects. In light of these difficulties, various types of manikins are finding use in automotive testing scenarios. These manikins can act as human surrogates from which local skin and core temperatures can be obtained, which are necessary for accurately predicting local and whole body thermal sensation and comfort using a physiology-based comfort model (e.g., the Berkeley Comfort Model). This paper evaluates two different types of manikins, i) an adaptive sweating thermal manikin, which is coupled with a human thermoregulation model, running in real-time, to obtain realistic skin temperatures; and, ii) a passive sensor manikin, which is used to measure boundary conditions as they would act on a human, from which skin and core temperatures can be predicted using a thermophysiological model. The simulated physiological responses and comfort obtained from both of these manikin-model coupling schemes are compared to those of a human subject within a vehicle cabin compartment transient heat-up scenario.

  1. Evaluation of onboard hyperspectral-image compression techniques for a parallel push-broom sensor

    Energy Technology Data Exchange (ETDEWEB)

    Briles, S.

    1996-04-01

    A single hyperspectral imaging sensor can produce frames with spatially-continuous rows of differing, but adjacent, spectral wavelength. If the frame sample-rate of the sensor is such that subsequent hyperspectral frames are spatially shifted by one row, then the sensor can be thought of as a parallel (in wavelength) push-broom sensor. An examination of data compression techniques for such a sensor is presented. The compression techniques are intended to be implemented onboard a space-based platform and to have implementation speeds that match the date rate of the sensor. Data partitions examined extend from individually operating on a single hyperspectral frame to operating on a data cube comprising the two spatial axes and the spectral axis. Compression algorithms investigated utilize JPEG-based image compression, wavelet-based compression and differential pulse code modulation. Algorithm performance is quantitatively presented in terms of root-mean-squared error and root-mean-squared correlation coefficient error. Implementation issues are considered in algorithm development.

  2. On Applicability of Network Coding Technique for 6LoWPAN-based Sensor Networks.

    Science.gov (United States)

    Amanowicz, Marek; Krygier, Jaroslaw

    2018-05-26

    In this paper, the applicability of the network coding technique in 6LoWPAN-based sensor multihop networks is examined. The 6LoWPAN is one of the standards proposed for the Internet of Things architecture. Thus, we can expect the significant growth of traffic in such networks, which can lead to overload and decrease in the sensor network lifetime. The authors propose the inter-session network coding mechanism that can be implemented in resource-limited sensor motes. The solution reduces the overall traffic in the network, and in consequence, the energy consumption is decreased. Used procedures take into account deep header compressions of the native 6LoWPAN packets and the hop-by-hop changes of the header structure. Applied simplifications reduce signaling traffic that is typically occurring in network coding deployments, keeping the solution usefulness for the wireless sensor networks with limited resources. The authors validate the proposed procedures in terms of end-to-end packet delay, packet loss ratio, traffic in the air, total energy consumption, and network lifetime. The solution has been tested in a real wireless sensor network. The results confirm the efficiency of the proposed technique, mostly in delay-tolerant sensor networks.

  3. Process sensors characterization based on noise analysis technique and artificial intelligence

    International Nuclear Information System (INIS)

    Mesquita, Roberto N. de; Perillo, Sergio R.P.; Santos, Roberto C. dos

    2005-01-01

    The time response of pressure and temperature sensors from the Reactor Protection System (RPS) is a requirement that must be satisfied in nuclear power plants, furthermore is an indicative of its degradation and its remaining life. The nuclear power industry and others have been eager to implement smart sensor technologies and digital instrumentation concepts to reduce manpower and effort currently spent on testing and calibration. Process parameters fluctuations during normal operation of a reactor are caused by random variations in neutron flux, heat transfer and other sources. The output sensor noise can be considered as the response of the system to an input representing the statistical nature of the underlying process which can be modeled using a time series model. Since the noise signal measurements are influenced by many factors, such as location of sensors, extraneous noise interference, and randomness in temperature and pressure fluctuation - the quantitative estimate of the time response using autoregressive noise modeling is subject to error. This technique has been used as means of sensor monitoring. In this work a set of pressure sensors installed in one experimental loop adapted from a flow calibration setup is used to test and analyze signals in a new approach using artificial intelligence techniques. A set of measurements of dynamic signals in different experimental conditions is used to distinguish and identify underlying process sources. A methodology that uses Blind Separation of Sources with a neural networks scheme is being developed to improve time response estimate reliability in noise analysis. (author)

  4. Process sensors characterization based on noise analysis technique and artificial intelligence

    Energy Technology Data Exchange (ETDEWEB)

    Mesquita, Roberto N. de; Perillo, Sergio R.P.; Santos, Roberto C. dos [Instituto de Pesquisas Energeticas e Nucleares (IPEN), Sao Paulo, SP (Brazil)]. E-mail: rnavarro@ipen.br; sperillo@ipen.br; rcsantos@ipen.br

    2005-07-01

    The time response of pressure and temperature sensors from the Reactor Protection System (RPS) is a requirement that must be satisfied in nuclear power plants, furthermore is an indicative of its degradation and its remaining life. The nuclear power industry and others have been eager to implement smart sensor technologies and digital instrumentation concepts to reduce manpower and effort currently spent on testing and calibration. Process parameters fluctuations during normal operation of a reactor are caused by random variations in neutron flux, heat transfer and other sources. The output sensor noise can be considered as the response of the system to an input representing the statistical nature of the underlying process which can be modeled using a time series model. Since the noise signal measurements are influenced by many factors, such as location of sensors, extraneous noise interference, and randomness in temperature and pressure fluctuation - the quantitative estimate of the time response using autoregressive noise modeling is subject to error. This technique has been used as means of sensor monitoring. In this work a set of pressure sensors installed in one experimental loop adapted from a flow calibration setup is used to test and analyze signals in a new approach using artificial intelligence techniques. A set of measurements of dynamic signals in different experimental conditions is used to distinguish and identify underlying process sources. A methodology that uses Blind Separation of Sources with a neural networks scheme is being developed to improve time response estimate reliability in noise analysis. (author)

  5. modern techniques and new sensors for determination of some metal ions

    International Nuclear Information System (INIS)

    Aglan, R.F.E.S.

    2004-01-01

    this work has been carried out to prepare some new sensors that can be used i the radioactive media. A novel homogenous solid state sensor responding to potassium ion was developed. i revealed good linear response with slope 44 ± 0.5 mV/decade over he concentration range 10 -4 -1.0 mol 1 -1 potassium ion with long life, high thermal and radiation stability. the influence of plasticizer, ionophore and conducting substrate on the analytical characterization of uranyl ion selective electrode was investigated. A new cesium sensor incorporating Cs-12- molybdophosphate as a sensing materials and DOP as solvent mediator in PVC matrix was constructed and used in the determination of cesium ion in the rage of 10 -5 10 -1 mol 1 -1 with a stop of 46±1.0 mV/decade in Ph range of 4-6

  6. Planar Indium Tin Oxide Heater for Improved Thermal Distribution for Metal Oxide Micromachined Gas Sensors

    Directory of Open Access Journals (Sweden)

    M. Cihan Çakır

    2016-09-01

    Full Text Available Metal oxide gas sensors with integrated micro-hotplate structures are widely used in the industry and they are still being investigated and developed. Metal oxide gas sensors have the advantage of being sensitive to a wide range of organic and inorganic volatile compounds, although they lack selectivity. To introduce selectivity, the operating temperature of a single sensor is swept, and the measurements are fed to a discriminating algorithm. The efficiency of those data processing methods strongly depends on temperature uniformity across the active area of the sensor. To achieve this, hot plate structures with complex resistor geometries have been designed and additional heat-spreading structures have been introduced. In this work we designed and fabricated a metal oxide gas sensor integrated with a simple square planar indium tin oxide (ITO heating element, by using conventional micromachining and thin-film deposition techniques. Power consumption–dependent surface temperature measurements were performed. A 420 °C working temperature was achieved at 120 mW power consumption. Temperature distribution uniformity was measured and a 17 °C difference between the hottest and the coldest points of the sensor at an operating temperature of 290 °C was achieved. Transient heat-up and cool-down cycle durations are measured as 40 ms and 20 ms, respectively.

  7. Planar Indium Tin Oxide Heater for Improved Thermal Distribution for Metal Oxide Micromachined Gas Sensors.

    Science.gov (United States)

    Çakır, M Cihan; Çalışkan, Deniz; Bütün, Bayram; Özbay, Ekmel

    2016-09-29

    Metal oxide gas sensors with integrated micro-hotplate structures are widely used in the industry and they are still being investigated and developed. Metal oxide gas sensors have the advantage of being sensitive to a wide range of organic and inorganic volatile compounds, although they lack selectivity. To introduce selectivity, the operating temperature of a single sensor is swept, and the measurements are fed to a discriminating algorithm. The efficiency of those data processing methods strongly depends on temperature uniformity across the active area of the sensor. To achieve this, hot plate structures with complex resistor geometries have been designed and additional heat-spreading structures have been introduced. In this work we designed and fabricated a metal oxide gas sensor integrated with a simple square planar indium tin oxide (ITO) heating element, by using conventional micromachining and thin-film deposition techniques. Power consumption-dependent surface temperature measurements were performed. A 420 °C working temperature was achieved at 120 mW power consumption. Temperature distribution uniformity was measured and a 17 °C difference between the hottest and the coldest points of the sensor at an operating temperature of 290 °C was achieved. Transient heat-up and cool-down cycle durations are measured as 40 ms and 20 ms, respectively.

  8. A GENERIC PACKAGING TECHNIQUE USING FLUIDIC ISOLATION FOR LOW-DRIFT IMPLANTABLE PRESSURE SENSORS.

    Science.gov (United States)

    Kim, A; Powell, C R; Ziaie, B

    2015-06-01

    This paper reports on a generic packaging method for reducing drift in implantable pressure sensors. The described technique uses fluidic isolation by encasing the pressure sensor in a liquid-filled medical-grade polyurethane balloon; thus, isolating it from surrounding aqueous environment that is the major source of baseline drift. In-vitro tests using commercial micromachined piezoresistive pressure sensors show an average baseline drift of 0.006 cmH 2 O/day (0.13 mmHg/month) for over 100 days of saline soak test, as compared to 0.101 cmH 2 O/day (2.23 mmHg/month) for a non-fluidic-isolated one soaked for 18 days. To our knowledge, this is the lowest reported drift for an implantable pressure sensor.

  9. Nonlinear optimal filter technique for analyzing energy depositions in TES sensors driven into saturation

    Directory of Open Access Journals (Sweden)

    B. Shank

    2014-11-01

    Full Text Available We present a detailed thermal and electrical model of superconducting transition edge sensors (TESs connected to quasiparticle (qp traps, such as the W TESs connected to Al qp traps used for CDMS (Cryogenic Dark Matter Search Ge and Si detectors. We show that this improved model, together with a straightforward time-domain optimal filter, can be used to analyze pulses well into the nonlinear saturation region and reconstruct absorbed energies with optimal energy resolution.

  10. Computerized data reduction techniques for nadir viewing remote sensors

    Science.gov (United States)

    Tiwari, S. N.; Gormsen, Barbara B.

    1985-01-01

    Computer resources have been developed for the analysis and reduction of MAPS experimental data from the OSTA-1 payload. The MAPS Research Project is concerned with the measurement of the global distribution of mid-tropospheric carbon monoxide. The measurement technique for the MAPS instrument is based on non-dispersive gas filter radiometer operating in the nadir viewing mode. The MAPS experiment has two passive remote sensing instruments, the prototype instrument which is used to measure tropospheric air pollution from aircraft platforms and the third generation (OSTA) instrument which is used to measure carbon monoxide in the mid and upper troposphere from space platforms. Extensive effort was also expended in support of the MAPS/OSTA-3 shuttle flight. Specific capabilities and resources developed are discussed.

  11. Validation Techniques for Sensor Data in Mobile Health Applications

    Directory of Open Access Journals (Sweden)

    Ivan Miguel Pires

    2016-01-01

    Full Text Available Mobile applications have become a must in every user’s smart device, and many of these applications make use of the device sensors’ to achieve its goal. Nevertheless, it remains fairly unknown to the user to which extent the data the applications use can be relied upon and, therefore, to which extent the output of a given application is trustworthy or not. To help developers and researchers and to provide a common ground of data validation algorithms and techniques, this paper presents a review of the most commonly used data validation algorithms, along with its usage scenarios, and proposes a classification for these algorithms. This paper also discusses the process of achieving statistical significance and trust for the desired output.

  12. Rancang Bangun Alat Ukur Kelajuan Udara Tipe Thermal Terintegrasi Termometer Udara Berbasis Sensor LM35 dan PT100

    Directory of Open Access Journals (Sweden)

    Laila Katriani

    2017-11-01

    INTEGRATED WITH AIR THERMOMETER USING  LM35 SENSOR AND PT100 SENSOR This research aimed to design a thermal type anemometer integrated with air thermometer using Lm35 sensor and PT100 sensor. The study began in Mei until Oktober 2016. The study was conducted at the Laboratory of Electronics and Instrumentation, Department of Physics Education, State University of Yogyakarta. The design of the thermal type anemometer consists of two stages, namely, the design of the hardware and software design. Hardware design consists of a sensor system design (LM35 and PT100,  LM317 design, system design for data processing and display. Software design using C language. Based on the results of tests that had been done, shows that the sensor output LM35, whic is voltage is proportional to temperature changes, which had a sensitivity of 0.009 volts / ºC and initial output voltage of the sensor when the temperature reach 0 °C is 0,041 volts. PT100 sensor output, which is resistance is proportional to temperature changes, which had sensitivity of 0.391 Ω/oC and initial output resistance of the sensor when temperature reach 28 °C is 100,8 Ω. Error percent of thermal-type air speed measuring instrument testing is 4%.

  13. Experimental design for the evaluation of high-T(sub c) superconductive thermal bridges in a sensor satellite

    Science.gov (United States)

    Scott, Elaine P.; Lee, Kasey M.

    1994-01-01

    Infrared sensor satellites, which consist of cryogenic infrared sensor detectors, electrical instrumentation, and data acquisition systems, are used to monitor the conditions of the earth's upper atmosphere in order to evaluate its present and future changes. Currently, the electrical connections (instrumentation), which act as thermal bridges between the cryogenic infrared sensor and the significantly warmer data acquisition unit of the sensor satellite system, constitute a significant portion of the heat load on the cryogen. As a part of extending the mission life of the sensor satellite system, the researchers at the National Aeronautics and Space Administration's Langley Research Center (NASA-LaRC) are evaluating the effectiveness of replacing the currently used manganin wires with high-temperature superconductive (HTS) materials as the electrical connections (thermal bridges). In conjunction with the study being conducted at NASA-LaRC, the proposed research is to design a space experiment to determine the thermal savings on a cryogenic subsystem when manganin leads are replaced by HTS leads printed onto a substrate with a low thermal conductivity, and to determine the thermal conductivities of HTS materials. The experiment is designed to compare manganin wires with two different types of superconductors on substrates by determining the heat loss by the thermal bridges and providing temperature measurements for the estimation of thermal conductivity. A conductive mathematical model has been developed and used as a key tool in the design process and subsequent analysis.

  14. Introducing Thermal Wave Transport Analysis (TWTA): A Thermal Technique for Dopamine Detection by Screen-Printed Electrodes Functionalized with Molecularly Imprinted Polymer (MIP) Particles.

    Science.gov (United States)

    Peeters, Marloes M; van Grinsven, Bart; Foster, Christopher W; Cleij, Thomas J; Banks, Craig E

    2016-04-26

    A novel procedure is developed for producing bulk modified Molecularly Imprinted Polymer (MIP) screen-printed electrodes (SPEs), which involves the direct mixing of the polymer particles within the screen-printed ink. This allowed reduction of the sample preparation time from 45 min to 1 min, and resulted in higher reproducibility of the electrodes. The samples are measured with a novel detection method, namely, thermal wave transport analysis (TWTA), relying on the analysis of thermal waves through a functional interface. As a first proof-of-principle, MIPs for dopamine are developed and successfully incorporated within a bulk modified MIP SPE. The detection limits of dopamine within buffer solutions for the MIP SPEs are determined via three independent techniques. With cyclic voltammetry this was determined to be 4.7 × 10(-6) M, whereas by using the heat-transfer method (HTM) 0.35 × 10(-6) M was obtained, and with the novel TWTA concept 0.26 × 10(-6) M is possible. This TWTA technique is measured simultaneously with HTM and has the benefits of reducing measurement time to less than 5 min and increasing effect size by nearly a factor of two. The two thermal methods are able to enhance dopamine detection by one order of magnitude compared to the electrochemical method. In previous research, it was not possible to measure neurotransmitters in complex samples with HTM, but with the improved signal-to-noise of TWTA for the first time, spiked dopamine concentrations were determined in a relevant food sample. In summary, novel concepts are presented for both the sensor functionalization side by employing screen-printing technology, and on the sensing side, the novel TWTA thermal technique is reported. The developed bio-sensing platform is cost-effective and suitable for mass-production due to the nature of screen-printing technology, which makes it very interesting for neurotransmitter detection in clinical diagnostic applications.

  15. Flush Mounting Of Thin-Film Sensors

    Science.gov (United States)

    Moore, Thomas C., Sr.

    1992-01-01

    Technique developed for mounting thin-film sensors flush with surfaces like aerodynamic surfaces of aircraft, which often have compound curvatures. Sensor mounted in recess by use of vacuum pad and materials selected for specific application. Technique involves use of materials tailored to thermal properties of substrate in which sensor mounted. Together with customized materials, enables flush mounting of thin-film sensors in most situations in which recesses for sensors provided. Useful in both aircraft and automotive industries.

  16. Energy neutral protocol based on hierarchical routing techniques for energy harvesting wireless sensor network

    Science.gov (United States)

    Muhammad, Umar B.; Ezugwu, Absalom E.; Ofem, Paulinus O.; Rajamäki, Jyri; Aderemi, Adewumi O.

    2017-06-01

    Recently, researchers in the field of wireless sensor networks have resorted to energy harvesting techniques that allows energy to be harvested from the ambient environment to power sensor nodes. Using such Energy harvesting techniques together with proper routing protocols, an Energy Neutral state can be achieved so that sensor nodes can run perpetually. In this paper, we propose an Energy Neutral LEACH routing protocol which is an extension to the traditional LEACH protocol. The goal of the proposed protocol is to use Gateway node in each cluster so as to reduce the data transmission ranges of cluster head nodes. Simulation results show that the proposed routing protocol achieves a higher throughput and ensure the energy neutral status of the entire network.

  17. A novel input-parasitic compensation technique for a nanopore-based CMOS DNA detection sensor

    Science.gov (United States)

    Kim, Jungsuk

    2016-12-01

    This paper presents a novel input-parasitic compensation (IPC) technique for a nanopore-based complementary metal-oxide-semiconductor (CMOS) DNA detection sensor. A resistive-feedback transimpedance amplifier is typically adopted as the headstage of a DNA detection sensor to amplify the minute ionic currents generated from a nanopore and convert them to a readable voltage range for digitization. But, parasitic capacitances arising from the headstage input and the nanopore often cause headstage saturation during nanopore sensing, thereby resulting in significant DNA data loss. To compensate for the unwanted saturation, in this work, we propose an area-efficient and automated IPC technique, customized for a low-noise DNA detection sensor, fabricated using a 0.35- μm CMOS process; we demonstrated this prototype in a benchtop test using an α-hemolysin ( α-HL) protein nanopore.

  18. Novel Hybrid Scheduling Technique for Sensor Nodes with Mixed Criticality Tasks.

    Science.gov (United States)

    Micea, Mihai-Victor; Stangaciu, Cristina-Sorina; Stangaciu, Valentin; Curiac, Daniel-Ioan

    2017-06-26

    Sensor networks become increasingly a key technology for complex control applications. Their potential use in safety- and time-critical domains has raised the need for task scheduling mechanisms specially adapted to sensor node specific requirements, often materialized in predictable jitter-less execution of tasks characterized by different criticality levels. This paper offers an efficient scheduling solution, named Hybrid Hard Real-Time Scheduling (H²RTS), which combines a static, clock driven method with a dynamic, event driven scheduling technique, in order to provide high execution predictability, while keeping a high node Central Processing Unit (CPU) utilization factor. From the detailed, integrated schedulability analysis of the H²RTS, a set of sufficiency tests are introduced and demonstrated based on the processor demand and linear upper bound metrics. The performance and correct behavior of the proposed hybrid scheduling technique have been extensively evaluated and validated both on a simulator and on a sensor mote equipped with ARM7 microcontroller.

  19. [Research progress and development trend of quantitative assessment techniques for urban thermal environment.

    Science.gov (United States)

    Sun, Tie Gang; Xiao, Rong Bo; Cai, Yun Nan; Wang, Yao Wu; Wu, Chang Guang

    2016-08-01

    Quantitative assessment of urban thermal environment has become a focus for urban climate and environmental science since the concept of urban heat island has been proposed. With the continual development of space information and computer simulation technology, substantial progresses have been made on quantitative assessment techniques and methods of urban thermal environment. The quantitative assessment techniques have been developed to dynamics simulation and forecast of thermal environment at various scales based on statistical analysis of thermal environment on urban-scale using the historical data of weather stations. This study reviewed the development progress of ground meteorological observation, thermal infrared remote sensing and numerical simulation. Moreover, the potential advantages and disadvantages, applicability and the development trends of these techniques were also summarized, aiming to add fundamental knowledge of understanding the urban thermal environment assessment and optimization.

  20. Remote Inspection Techniques for Reactor Internals of Liquid Metal Reactor by using Ultrasonic Waveguide Sensor

    International Nuclear Information System (INIS)

    Joo, Young Sang; Kim, Seok Hun; Lee, Jae Han

    2006-02-01

    The primary components such as a reactor core, heat exchangers, pumps and internal structures of a liquid metal reactor (LMR) are submerged in hot sodium of reactor vessel. The division 3 of ASME code section XI specifies the visual inspection and continuous monitoring as major in-service inspection (ISI) methods of reactor internal structures. Reactor core and internal structures of LMR can not be visually examined due to an opaque liquid sodium. The under-sodium viewing and remote inspection techniques by using an ultrasonic wave should be applied for the in-service inspection of reactor internals. The remote inspection techniques using ultrasonic wave have been developed and applied for the visualization and ISI of reactor internals. The under sodium viewing technique has a limitation for the application of LMR due to the high temperature and irradiation environment. In this study, an ultrasonic waveguide sensor with a strip plate has been developed for an application to the under-sodium viewing and remote inspection. The Lamb wave propagation of a waveguide sensor has been analyzed and the zero-order antisymmetric A 0 plate wave was selected as the application mode of the sensor. The A 0 plate wave can be propagated in the dispersive low frequency range by using a liquid wedge clamped to the waveguide. A new technique is presented which is capable of steering the radiation beam angle of a waveguide sensor without a mechanical movement of the sensor assembly. The steering function of the ultrasonic radiation beam can be achieved by a frequency tuning method of the excitation pulse in the dispersive range of the A 0 mode. The technique provides an opportunity to overcome the scanning limitation of a waveguide sensor. The beam steering function has been evaluated by an experimental verification. The ultrasonic C-scanning experiments are performed in water and the feasibility of the ultrasonic waveguide sensor has been verified. The various remote inspection

  1. Optimal sensor locations for the backward Lagrangian stochastic technique in measuring lagoon gas emission

    Science.gov (United States)

    This study evaluated the impact of gas concentration and wind sensor locations on the accuracy of the backward Lagrangian stochastic inverse-dispersion technique (bLS) for measuring gas emission rates from a typical lagoon environment. Path-integrated concentrations (PICs) and 3-dimensional (3D) wi...

  2. Refractive index sensor based on optical fiber end face using pulse reference-based compensation technique

    Science.gov (United States)

    Bian, Qiang; Song, Zhangqi; Zhang, Xueliang; Yu, Yang; Chen, Yuzhong

    2018-03-01

    We proposed a refractive index sensor based on optical fiber end face using pulse reference-based compensation technique. With good compensation effect of this compensation technique, the power fluctuation of light source, the change of optic components transmission loss and coupler splitting ratio can be compensated, which largely reduces the background noise. The refractive index resolutions can achieve 3.8 × 10-6 RIU and1.6 × 10-6 RIU in different refractive index regions.

  3. Fiber-Optic Thermal Sensor for TiN Film Crack Monitoring

    Directory of Open Access Journals (Sweden)

    Hsiang-Chang Hsu

    2017-11-01

    Full Text Available The study focuses on the thermal and temperature sensitivity behavior of an optical fiber sensor device. In this article, a titanium nitride (TiN-coated fiber Bragg grating (FBG sensor fabricated using an ion beam sputtering system was investigated. The reflection spectra of the FBG sensor were tested using R-soft optical software to simulate the refractive index sensitivity. In these experiments, the temperature sensitivity of the TiN FBG was measured at temperatures ranging from 100 to 500 °C using an optical spectrum analyzer (OSA. The results showed that the temperature sensitivity of the proposed TiN FBG sensor reached 12.8 pm/°C for the temperature range of 100 to 300 °C and 20.8 pm/°C for the temperature range of 300 to 500 °C. Additionally, we found that the produced oxidation at temperatures of 400-500 °C caused a crack, with the crack becoming more and more obvious at higher and higher temperatures.

  4. Design of an optical thermal sensor for proton exchange membrane fuel cell temperature measurement using phosphor thermometry

    Science.gov (United States)

    Inman, Kristopher; Wang, Xia; Sangeorzan, Brian

    Internal temperatures in a proton exchange membrane (PEM) fuel cell govern the ionic conductivities of the polymer electrolyte, influence the reaction rate at the electrodes, and control the water vapor pressure inside the cell. It is vital to fully understand thermal behavior in a PEM fuel cell if performance and durability are to be optimized. The objective of this research was to design, construct, and implement thermal sensors based on the principles of the lifetime-decay method of phosphor thermometry to measure temperatures inside a PEM fuel cell. Five sensors were designed and calibrated with a maximum uncertainty of ±0.6 °C. Using these sensors, surface temperatures were measured on the cathode gas diffusion layer of a 25 cm 2 PEM fuel cell. The test results demonstrate the utility of the optical temperature sensor design and provide insight into the thermal behavior found in a PEM fuel cell.

  5. A Data-Driven Response Virtual Sensor Technique with Partial Vibration Measurements Using Convolutional Neural Network

    Science.gov (United States)

    Sun, Shan-Bin; He, Yuan-Yuan; Zhou, Si-Da; Yue, Zhen-Jiang

    2017-01-01

    Measurement of dynamic responses plays an important role in structural health monitoring, damage detection and other fields of research. However, in aerospace engineering, the physical sensors are limited in the operational conditions of spacecraft, due to the severe environment in outer space. This paper proposes a virtual sensor model with partial vibration measurements using a convolutional neural network. The transmissibility function is employed as prior knowledge. A four-layer neural network with two convolutional layers, one fully connected layer, and an output layer is proposed as the predicting model. Numerical examples of two different structural dynamic systems demonstrate the performance of the proposed approach. The excellence of the novel technique is further indicated using a simply supported beam experiment comparing to a modal-model-based virtual sensor, which uses modal parameters, such as mode shapes, for estimating the responses of the faulty sensors. The results show that the presented data-driven response virtual sensor technique can predict structural response with high accuracy. PMID:29231868

  6. A Data-Driven Response Virtual Sensor Technique with Partial Vibration Measurements Using Convolutional Neural Network.

    Science.gov (United States)

    Sun, Shan-Bin; He, Yuan-Yuan; Zhou, Si-Da; Yue, Zhen-Jiang

    2017-12-12

    Measurement of dynamic responses plays an important role in structural health monitoring, damage detection and other fields of research. However, in aerospace engineering, the physical sensors are limited in the operational conditions of spacecraft, due to the severe environment in outer space. This paper proposes a virtual sensor model with partial vibration measurements using a convolutional neural network. The transmissibility function is employed as prior knowledge. A four-layer neural network with two convolutional layers, one fully connected layer, and an output layer is proposed as the predicting model. Numerical examples of two different structural dynamic systems demonstrate the performance of the proposed approach. The excellence of the novel technique is further indicated using a simply supported beam experiment comparing to a modal-model-based virtual sensor, which uses modal parameters, such as mode shapes, for estimating the responses of the faulty sensors. The results show that the presented data-driven response virtual sensor technique can predict structural response with high accuracy.

  7. Fabrication of flex sensors through direct ink write technique and its electrical characterization

    Science.gov (United States)

    Abas, Muhammad; Rahman, Khalid

    2016-11-01

    The present work is intended to fabricate low-cost flex sensor from conductive carbon paste using direct ink write (DIW) technique. DIW method is one of the additive manufacturing processes, which is capable to deposit a variety of material on a variety of substrates by a different mechanism to feature resolution at a microns level. It is widely used in the electronic industry for fabrication of PCBS and electrodes for different electronic devices. The DIW system in present study extrudes material stored in the syringe barrel through nozzle using compressed air. This mechanism will assist in creating patterns on a variety of substrates. Pneumatic controller is employed to control deposition of material, while computer-controlled X-Y stage is employed to control pattern generation. For effective and control patterning, printing parameters were optimized using Taguchi design optimization technique. The conductive carbon paste is used as ink for pattern generation on flexible PET substrate. Samples of flex sensor having different dimensions are prepared through DIW. The fabricated sensors were used as flexion sensor, and its electrical characteristic was evaluated. The obtained sensors are stable and reliable in performance.

  8. Thermal detection mechanism of SiC based hydrogen resistive gas sensors

    Science.gov (United States)

    Fawcett, Timothy J.; Wolan, John T.; Lloyd Spetz, Anita; Reyes, Meralys; Saddow, Stephen E.

    2006-10-01

    Silicon carbide (SiC) resistive hydrogen gas sensors have been fabricated and tested. Planar NiCr contacts were deposited on a thin 3C-SiC epitaxial film grown on thin Si wafers bonded to polycrystalline SiC substrates. At 673K, up to a 51.75±0.04% change in sensor output current and a change in the device temperature of up to 163.1±0.4K were demonstrated in response to 100% H2 in N2. Changes in device temperature are shown to be driven by the transfer of heat from the device to the gas, giving rise to a thermal detection mechanism.

  9. A Survey on Optimal Signal Processing Techniques Applied to Improve the Performance of Mechanical Sensors in Automotive Applications

    Science.gov (United States)

    Hernandez, Wilmar

    2007-01-01

    In this paper a survey on recent applications of optimal signal processing techniques to improve the performance of mechanical sensors is made. Here, a comparison between classical filters and optimal filters for automotive sensors is made, and the current state of the art of the application of robust and optimal control and signal processing techniques to the design of the intelligent (or smart) sensors that today's cars need is presented through several experimental results that show that the fusion of intelligent sensors and optimal signal processing techniques is the clear way to go. However, the switch between the traditional methods of designing automotive sensors and the new ones cannot be done overnight because there are some open research issues that have to be solved. This paper draws attention to one of the open research issues and tries to arouse researcher's interest in the fusion of intelligent sensors and optimal signal processing techniques.

  10. Techniques for the thermal/hydraulic analysis of LMFBR check valves

    International Nuclear Information System (INIS)

    Cho, S.M.; Kane, R.S.

    1979-01-01

    A thermal/hydraulic analysis of the check valves in liquid sodium service for LMFBR plants is required to provide temperature data for thermal stress analysis of the valves for specified transient conditions. Because of the complex three-dimensional flow pattern within the valve, the heat transfer analysis techniques for less complicated shapes could not be used. This paper discusses the thermal analysis techniques used to assure that the valve stress analysis is conservative. These techniques include a method for evaluating the recirculating flow patterns and for selecting appropriately conservative heat transfer correlations in various regions of the valve

  11. Standard Test Method for Determining Thermal Neutron Reaction Rates and Thermal Neutron Fluence Rates by Radioactivation Techniques

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2008-01-01

    1.1 The purpose of this test method is to define a general procedure for determining an unknown thermal-neutron fluence rate by neutron activation techniques. It is not practicable to describe completely a technique applicable to the large number of experimental situations that require the measurement of a thermal-neutron fluence rate. Therefore, this method is presented so that the user may adapt to his particular situation the fundamental procedures of the following techniques. 1.1.1 Radiometric counting technique using pure cobalt, pure gold, pure indium, cobalt-aluminum, alloy, gold-aluminum alloy, or indium-aluminum alloy. 1.1.2 Standard comparison technique using pure gold, or gold-aluminum alloy, and 1.1.3 Secondary standard comparison techniques using pure indium, indium-aluminum alloy, pure dysprosium, or dysprosium-aluminum alloy. 1.2 The techniques presented are limited to measurements at room temperatures. However, special problems when making thermal-neutron fluence rate measurements in high-...

  12. The effect of winding and core support material on the thermal gain dependence of a fluxgate magnetometer sensor

    Science.gov (United States)

    Miles, David M.; Mann, Ian R.; Kale, Andy; Milling, David K.; Narod, Barry B.; Bennest, John R.; Barona, David; Unsworth, Martyn J.

    2017-10-01

    Fluxgate magnetometers are an important tool in geophysics and space physics but are typically sensitive to variations in sensor temperature. Changes in instrumental gain with temperature, thermal gain dependence, are thought to be predominantly due to changes in the geometry of the wire coils that sense the magnetic field and/or provide magnetic feedback. Scientific fluxgate magnetometers typically employ some form of temperature compensation and support and constrain wire sense coils with bobbins constructed from materials such as MACOR machinable ceramic (Corning Inc.) which are selected for their ultra-low thermal deformation rather than for robustness, cost, or ease of manufacturing. We present laboratory results comparing the performance of six geometrically and electrically matched fluxgate sensors in which the material used to support the windings and for the base of the sensor is varied. We use a novel, low-cost thermal calibration procedure based on a controlled sinusoidal magnetic source and quantitative spectral analysis to measure the thermal gain dependence of fluxgate magnetometer sensors at the ppm°C-1 level in a typical magnetically noisy university laboratory environment. We compare the thermal gain dependence of sensors built from MACOR, polyetheretherketone (PEEK) engineering plastic (virgin, 30 % glass filled and 30 % carbon filled), and acetal to examine the trade between the thermal properties of the material, the impact on the thermal gain dependence of the fluxgate, and the cost and ease of manufacture. We find that thermal gain dependence of the sensor varies as one half of the material properties of the bobbin supporting the wire sense coils rather than being directly related as has been historically thought. An experimental sensor constructed from 30 % glass-filled PEEK (21.6 ppm°C-1) had a thermal gain dependence within 5 ppm°C-1 of a traditional sensor constructed from MACOR ceramic (8.1 ppm°C-1). If a modest increase in thermal

  13. The effect of winding and core support material on the thermal gain dependence of a fluxgate magnetometer sensor

    Directory of Open Access Journals (Sweden)

    D. M. Miles

    2017-10-01

    Full Text Available Fluxgate magnetometers are an important tool in geophysics and space physics but are typically sensitive to variations in sensor temperature. Changes in instrumental gain with temperature, thermal gain dependence, are thought to be predominantly due to changes in the geometry of the wire coils that sense the magnetic field and/or provide magnetic feedback. Scientific fluxgate magnetometers typically employ some form of temperature compensation and support and constrain wire sense coils with bobbins constructed from materials such as MACOR machinable ceramic (Corning Inc. which are selected for their ultra-low thermal deformation rather than for robustness, cost, or ease of manufacturing. We present laboratory results comparing the performance of six geometrically and electrically matched fluxgate sensors in which the material used to support the windings and for the base of the sensor is varied. We use a novel, low-cost thermal calibration procedure based on a controlled sinusoidal magnetic source and quantitative spectral analysis to measure the thermal gain dependence of fluxgate magnetometer sensors at the ppm°C−1 level in a typical magnetically noisy university laboratory environment. We compare the thermal gain dependence of sensors built from MACOR, polyetheretherketone (PEEK engineering plastic (virgin, 30 % glass filled and 30 % carbon filled, and acetal to examine the trade between the thermal properties of the material, the impact on the thermal gain dependence of the fluxgate, and the cost and ease of manufacture. We find that thermal gain dependence of the sensor varies as one half of the material properties of the bobbin supporting the wire sense coils rather than being directly related as has been historically thought. An experimental sensor constructed from 30 % glass-filled PEEK (21.6 ppm°C−1 had a thermal gain dependence within 5 ppm°C−1 of a traditional sensor constructed from MACOR ceramic (8.1

  14. New Sensors and Techniques for the Structural Health Monitoring of Propulsion Systems

    Directory of Open Access Journals (Sweden)

    Mark Woike

    2013-01-01

    Full Text Available The ability to monitor the structural health of the rotating components, especially in the hot sections of turbine engines, is of major interest to aero community in improving engine safety and reliability. The use of instrumentation for these applications remains very challenging. It requires sensors and techniques that are highly accurate, are able to operate in a high temperature environment, and can detect minute changes and hidden flaws before catastrophic events occur. The National Aeronautics and Space Administration (NASA, through the Aviation Safety Program (AVSP, has taken a lead role in the development of new sensor technologies and techniques for the in situ structural health monitoring of gas turbine engines. This paper presents a summary of key results and findings obtained from three different structural health monitoring approaches that have been investigated. This includes evaluating the performance of a novel microwave blade tip clearance sensor; a vibration based crack detection technique using an externally mounted capacitive blade tip clearance sensor; and lastly the results of using data driven anomaly detection algorithms for detecting cracks in a rotating disk.

  15. Effects of water-absorption and thermal drift on a polymeric photonic crystal slab sensor

    DEFF Research Database (Denmark)

    Sørensen, Kristian Tølbøl; Ingvorsen, Charlotte Bonde; Nielsen, Line Hagner

    2018-01-01

    of resonant reflection during absorption, by monitoring the release of water using ellipsometry, and by rigorous coupled-wave analysis (RCWA). The approach presented here enables monitoring of water uptake and thermal fluctuations, for drift-free, high-performance operation of a polymeric PCS sensor....... with additional challenges, besides those relating to temperature-variations, which must be considered in any refractive index based method: The polymeric waveguide core was found to swell by ?0.3% as water absorbed into the waveguide core over ?1.5 h. This was investigated by monitoring the wavelength...

  16. In-flight thermal experiments for LISA Pathfinder: Simulating temperature noise at the Inertial Sensors

    International Nuclear Information System (INIS)

    Armano, M; Audley, H; Born, M; Danzmann, K; Diepholz, I; Auger, G; Binetruy, P; Baird, J; Bortoluzzi, D; Brandt, N; Fitzsimons, E; Bursi, A; Caleno, M; Cavalleri, A; Cesarini, A; Dolesi, R; Ferroni, V; Cruise, M; Dunbar, N; Ferraioli, L

    2015-01-01

    Thermal Diagnostics experiments to be carried out on board LISA Pathfinder (LPF) will yield a detailed characterisation of how temperature fluctuations affect the LTP (LISA Technology Package) instrument performance, a crucial information for future space based gravitational wave detectors as the proposed eLISA. Amongst them, the study of temperature gradient fluctuations around the test masses of the Inertial Sensors will provide as well information regarding the contribution of the Brownian noise, which is expected to limit the LTP sensitivity at frequencies close to 1 mHz during some LTP experiments. In this paper we report on how these kind of Thermal Diagnostics experiments were simulated in the last LPF Simulation Campaign (November, 2013) involving all the LPF Data Analysis team and using an end-to-end simulator of the whole spacecraft. Such simulation campaign was conducted under the framework of the preparation for LPF operations. (paper)

  17. Thermal conductivity measurement of the He-ion implanted layer of W using transient thermoreflectance technique

    Energy Technology Data Exchange (ETDEWEB)

    Qu, Shilian; Li, Yuanfei [Laboratory of Advanced Materials, School of Materials Science and Engineering, Tsinghua University, Beijing 100084 (China); Wang, Zhigang [Department of Electronic Engineering, Dalian University of Technology, Dalian 116024 (China); Jia, Yuzhen [Laboratory of Advanced Materials, School of Materials Science and Engineering, Tsinghua University, Beijing 100084 (China); Science and Technology on Reactor Fuel and Materials Laboratory, Nuclear Power Institute of China, Chengdu 610213 (China); Li, Chun [School of Mechanical and Materials Engineering, North China University of Technology, Beijing 100144 (China); Xu, Ben; Chen, Wanqi [Laboratory of Advanced Materials, School of Materials Science and Engineering, Tsinghua University, Beijing 100084 (China); Bai, Suyuan [School of Physics and Electronic Technology, Liaoning Normal University, Dalian 116029 (China); Huang, Zhengxing; Tang, Zhenan [Department of Electronic Engineering, Dalian University of Technology, Dalian 116024 (China); Liu, Wei, E-mail: liuw@mail.tsinghua.edu.cn [Laboratory of Advanced Materials, School of Materials Science and Engineering, Tsinghua University, Beijing 100084 (China)

    2017-02-15

    Transient thermoreflectance method was applied on the thermal conductivity measurement of the surface damaged layer of He-implanted tungsten. Uniform damages tungsten surface layer was produced by multi-energy He-ion implantation with thickness of 450 nm. Result shows that the thermal conductivity is reduced by 90%. This technique was further applied on sample with holes on the surface, which was produced by the He-implanted at 2953 K. The thermal conductivity decreases to 3% from the bulk value.

  18. Layout-Driven Post-Placement Techniques for Temperature Reduction and Thermal Gradient Minimization

    DEFF Research Database (Denmark)

    Liu, Wei; Calimera, Andrea; Macii, Alberto

    2013-01-01

    With the continuing scaling of CMOS technology, on-chip temperature and thermal-induced variations have become a major design concern. To effectively limit the high temperature in a chip equipped with a cost-effective cooling system, thermal specific approaches, besides low power techniques, are ...

  19. Review of simulation techniques for Aquifer Thermal Energy Storage (ATES)

    Science.gov (United States)

    Mercer, J. W.; Faust, C. R.; Miller, W. J.; Pearson, F. J., Jr.

    1981-03-01

    The analysis of aquifer thermal energy storage (ATES) systems rely on the results from mathematical and geochemical models. Therefore, the state-of-the-art models relevant to ATES were reviewed and evaluated. These models describe important processes active in ATES including ground-water flow, heat transport (heat flow), solute transport (movement of contaminants), and geochemical reactions. In general, available models of the saturated ground-water environment are adequate to address most concerns associated with ATES; that is, design, operation, and environmental assessment. In those cases where models are not adequate, development should be preceded by efforts to identify significant physical phenomena and relate model parameters to measurable quantities.

  20. Hot filament technique for measuring the thermal conductivity of molten lithium fluoride

    Science.gov (United States)

    Jaworske, Donald A.; Perry, William D.

    1990-01-01

    Molten salts, such as lithium fluoride, are attractive candidates for thermal energy storage in solar dynamic space power systems because of their high latent heat of fusion. However, these same salts have poor thermal conductivities which inhibit the transfer of heat into the solid phase and out of the liquid phase. One concept for improving the thermal conductivity of the thermal energy storage system is to add a conductive filler material to the molten salt. High thermal conductivity pitch-based graphite fibers are being considered for this application. Although there is some information available on the thermal conductivity of lithium fluoride solid, there is very little information on lithium fluoride liquid, and no information on molten salt graphite fiber composites. This paper describes a hot filament technique for determining the thermal conductivity of molten salts. The hot filament technique was used to find the thermal conductivity of molten lithium fluoride at 930 C, and the thermal conductivity values ranged from 1.2 to 1.6 W/mK. These values are comparable to the slightly larger value of 5.0 W/mK for lithium fluoride solid. In addition, two molten salt graphite fiber composites were characterized with the hot filament technique and these results are also presented.

  1. Fabrication of amorphous InGaZnO thin-film transistor-driven flexible thermal and pressure sensors

    International Nuclear Information System (INIS)

    Park, Ick-Joon; Jeong, Chan-Yong; Song, Sang-Hun; Kwon, Hyuck-In; Cho, In-Tak; Lee, Jong-Ho; Cho, Eou-Sik; Kwon, Sang Jik; Kim, Bosul; Cheong, Woo-Seok

    2012-01-01

    In this work, we present the results concerning the use of amorphous indium–gallium–zinc–oxide (a-IGZO) thin-film transistor (TFT) as a driving transistor of the flexible thermal and pressure sensors which are applicable to artificial skin systems. Although the a-IGZO TFT has been attracting much attention as a driving transistor of the next-generation flat panel displays, no study has been performed about the application of this new device to the driving transistor of the flexible sensors yet. The proposed thermal sensor pixel is composed of the series-connected a-IGZO TFT and ZnO-based thermistor fabricated on a polished metal foil, and the ZnO-based thermistor is replaced by the pressure sensitive rubber in the pressure sensor pixel. In both sensor pixels, the a-IGZO TFT acts as the driving transistor and the temperature/pressure-dependent resistance of the ZnO-based thermistor/pressure-sensitive rubber mainly determines the magnitude of the output currents. The fabricated a-IGZO TFT-driven flexible thermal sensor shows around a seven times increase in the output current as the temperature increases from 20 °C to 100 °C, and the a-IGZO TFT-driven flexible pressure sensors also exhibit high sensitivity under various pressure environments. (paper)

  2. Optical temperature sensor based on the Nd{sup 3+} infrared thermalized emissions in a fluorotellurite glass

    Energy Technology Data Exchange (ETDEWEB)

    Lalla, E.A. [Departamento de Física, Universidad de la Laguna, San Cristóbal de la Laguna, 38200 Santa Cruz de Tenerife (Spain); León-Luis, S.F., E-mail: sleonlui@ull.es [Departamento de Física, Universidad de la Laguna, San Cristóbal de la Laguna, 38200 Santa Cruz de Tenerife (Spain); Malta Consolider Team, Universidad de la Laguna, San Cristóbal de la Laguna, 38200 Santa Cruz de Tenerife (Spain); Monteseguro, V. [Departamento de Física, Universidad de la Laguna, San Cristóbal de la Laguna, 38200 Santa Cruz de Tenerife (Spain); Malta Consolider Team, Universidad de la Laguna, San Cristóbal de la Laguna, 38200 Santa Cruz de Tenerife (Spain); Pérez-Rodríguez, C. [Departamento de Física, Universidad de la Laguna, San Cristóbal de la Laguna, 38200 Santa Cruz de Tenerife (Spain); Cáceres, J.M. [Departamento de Ingeniería Industrial, Universidad de la Laguna, San Cristóbal de la Laguna, 38200 Santa Cruz de Tenerife (Spain); and others

    2015-10-15

    The temperature dependence of the infrared luminescence of a fluorotellurite glass doped with 0.01 and 2.5 mol% of Nd{sup 3+} ions was studied in order to use it as a high temperature sensing probe. For this purpose, the emission intensities of the ({sup 4}S{sub 3/2}, {sup 4}F{sub 7/2}), ({sup 2}H{sub 9/2}, {sup 4}F{sub 5/2}),{sup 4}F{sub 3/2}→{sup 4}I{sub 9/2} transitions were measured in a wide range of temperatures from 300 upto 650 K. The changes in the emission profiles were calibrated by means of the fluorescence intensity ratio technique. The calibrations showed a strong dependence on the Nd{sup 3+} ions concentration, having the low-doped concentrated sample the best response to changes of temperature. The maximum value obtained for the thermal sensibility is 17×10{sup −4} K{sup −1} at 640 K, being one of the highest values found in the literature for Nd{sup 3+} optical temperature sensors. Finally, the experimental calibrations were compared with the theoretical temperature luminescence response calculated from the Judd–Ofelt theory. - Highlights: • Nd{sup 3+}-doped fluorotellurite glasses were prepared. • The intensities of the ({sup 4}S{sub 3/2},{sup 4}F{sub 7/2}),({sup 2}H{sub 9/2},{sup 4}F{sub 5/2}), {sup 4}F{sub 3/2}→{sup 4}I{sub 9/2} transitions. • The highest thermal sensitivity has been obtained for the glass with the lowest concentration of Nd{sup 3+} ions. • The Nd{sup 3+}-doped fluorotellurite glass fits the requirement for a good temperature sensor.

  3. Thermal analysis of cracked bodies using finite element techniques

    International Nuclear Information System (INIS)

    Hellen, T.K.; Price, R.H.; Harrison, R.P.

    1975-01-01

    The paper develops the potential energy equation in terms of finite element theory including thermal loads. Following this, the energy release rate and consequently the stress intensity factors are derived. Considerations of the classical near crack tip equations are made and deficiencies with the popular substitution methods are highlighted. A method of removing these deficiencies is described. Various energy methods are reconsidered in terms of the role of the thermal energy contribution to the potential energy. These methods include work of crack closure, energy compliance and virtual crack extensions with no other change in nodal geometry, and therefore only requires the recalculation of the stiffness matrices of the crack tip elements. An example of a quadratic temperature gradient parallel to the crack plane in an edge cracked plate is described. Comparisons of the various finite element methods are made and generally show good agreement. A second application compares the virtual crack extension method with an approximate analytical solution in determining stress intensity factors for a thick hollow cylinder with an axial crack for various depths through the wall thickness and for different times. Initially the cylinder is at a uniform high temperature and is then subjected to a sustained cooling shock. Analytical solutions are available for temperature and stress distributions in the uncracked pipe. The stress intensity for a shallow crack in the early stages of the transient has been determined using a superposition procedure. Comparison of the analytical and computed results shows good agreement between the methods

  4. Investigation of Thermal Interface Materials Using Phase-Sensitive Transient Thermoreflectance Technique: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Feng, X.; King, C.; DeVoto, D.; Mihalic, M.; Narumanchi, S.

    2014-08-01

    With increasing power density in electronics packages/modules, thermal resistances at multiple interfaces are a bottleneck to efficient heat removal from the package. In this work, the performance of thermal interface materials such as grease, thermoplastic adhesives and diffusion-bonded interfaces are characterized using the phase-sensitive transient thermoreflectance technique. A multi-layer heat conduction model was constructed and theoretical solutions were derived to obtain the relation between phase lag and the thermal/physical properties. This technique enables simultaneous extraction of the contact resistance and bulk thermal conductivity of the TIMs. With the measurements, the bulk thermal conductivity of Dow TC-5022 thermal grease (70 to 75 um bondline thickness) was 3 to 5 W/(m-K) and the contact resistance was 5 to 10 mm2-K/W. For the Btech thermoplastic material (45 to 80 μm bondline thickness), the bulk thermal conductivity was 20 to 50 W/(m-K) and the contact resistance was 2 to 5 mm2-K/W. Measurements were also conducted to quantify the thermal performance of diffusion-bonded interface for power electronics applications. Results with the diffusion-bonded sample showed that the interfacial thermal resistance is more than one order of magnitude lower than those of traditional TIMs, suggesting potential pathways to efficient thermal management.

  5. The Measurement of Thermal Diffusivity in Conductor and Insulator by Photodeflection Technique

    Science.gov (United States)

    Achathongsuk, U.; Rittidach, T.; Tipmonta, P.; Kijamnajsuk, P.; Chotikaprakhan, S.

    2017-09-01

    The purpose of this study is to estimate thermal diffusivities of high thermal diffusivity bulk material as well as low thermal diffusivity bulk material by using many types of fluid such as Ethyl alcohol and water. This method is studied by measuring amplitude and phase of photodeflection signal in various frequency modulations. The experimental setup consists of two laser lines: 1) a pump laser beams through a modulator, varied frequency, controlled by lock-in amplifier and focused on sample surface by lens. 2) a probe laser which parallels with the sample surface and is perpendicular to the pump laser beam. The probe laser deflection signal is obtained by a position sensor which controlled by lock-in amplifier. Thermal diffusivity is calculated by measuring the amplitude and phase of the photodeflection signal and compared with the thermal diffusivity of a standard value. The thermal diffusivity of SGG agrees well with the literature but the thermal diffusivity of Cu is less than the literature value by a factor of ten. The experiment requires further improvement to measure the thermal diffusivity of Cu. However, we succeed in using ethyl alcohol as the coupling medium instead of CCl4 which is highly toxic.

  6. A near-optimal low complexity sensor fusion technique for accurate indoor localization based on ultrasound time of arrival measurements from low-quality sensors

    Science.gov (United States)

    Mitilineos, Stelios A.; Argyreas, Nick D.; Thomopoulos, Stelios C. A.

    2009-05-01

    A fusion-based localization technique for location-based services in indoor environments is introduced herein, based on ultrasound time-of-arrival measurements from multiple off-the-shelf range estimating sensors which are used in a market-available localization system. In-situ field measurements results indicated that the respective off-the-shelf system was unable to estimate position in most of the cases, while the underlying sensors are of low-quality and yield highly inaccurate range and position estimates. An extensive analysis is performed and a model of the sensor-performance characteristics is established. A low-complexity but accurate sensor fusion and localization technique is then developed, which consists inof evaluating multiple sensor measurements and selecting the one that is considered most-accurate based on the underlying sensor model. Optimality, in the sense of a genie selecting the optimum sensor, is subsequently evaluated and compared to the proposed technique. The experimental results indicate that the proposed fusion method exhibits near-optimal performance and, albeit being theoretically suboptimal, it largely overcomes most flaws of the underlying single-sensor system resulting in a localization system of increased accuracy, robustness and availability.

  7. Compression and Combining Based on Channel Shortening and Rank Reduction Technique for Cooperative Wireless Sensor Networks

    KAUST Repository

    Ahmed, Qasim Zeeshan

    2013-12-18

    This paper investigates and compares the performance of wireless sensor networks where sensors operate on the principles of cooperative communications. We consider a scenario where the source transmits signals to the destination with the help of L sensors. As the destination has the capacity of processing only U out of these L signals, the strongest U signals are selected while the remaining (L?U) signals are suppressed. A preprocessing block similar to channel-shortening is proposed in this contribution. However, this preprocessing block employs a rank-reduction technique instead of channel-shortening. By employing this preprocessing, we are able to decrease the computational complexity of the system without affecting the bit error rate (BER) performance. From our simulations, it can be shown that these schemes outperform the channel-shortening schemes in terms of computational complexity. In addition, the proposed schemes have a superior BER performance as compared to channel-shortening schemes when sensors employ fixed gain amplification. However, for sensors which employ variable gain amplification, a tradeoff exists in terms of BER performance between the channel-shortening and these schemes. These schemes outperform channel-shortening scheme for lower signal-to-noise ratio.

  8. Numerical Prediction of a Bi-Directional Micro Thermal Flow Sensors

    Directory of Open Access Journals (Sweden)

    M. Al-Amayrah

    2011-09-01

    Full Text Available Thermal flow sensors such as hot-wire anemometer (HWA can be used to measure the flow velocity with certain accuracy. However, HWA can measure the flow velocity without determining the flow direction. Pulsed-Wire Anemometer (PWA with 3 wires can be used to measure flow velocity and flow directions. The present study aims to develop a numerical analysis of unsteady flow around a pulsed hot-wire anemometer using three parallel wires. The pulsed wire which is called the heated wire is located in the middle and the two sensor wires are installed upstream and downstream of the pulsed wire. 2-D numerical models were built and simulated using different wires arrangements. The ratio of the separation distance between the heated wire and sensor wire (x to the diameter of the heated wire (D ratios (x/D was varied between 3.33 and 183.33. The output results are plotted as a function of Peclet number (convection time / diffusion time. It was found that as the ratio of x/D increases, the sensitivity of PWA device to the time of flight decreases. But at the same the reading of the time of flight becomes more accurate, because the effects of the diffusion and wake after the heated wire decrease. Also, a very good agreement has been obtained between the present numerical simulation and the previous experimental data.

  9. Review of simulation techniques for aquifer thermal energy storage (ATES)

    Energy Technology Data Exchange (ETDEWEB)

    Mercer, J.W.; Faust, C.R.; Miller, W.J.; Pearson, F.J. Jr.

    1981-03-01

    The storage of thermal energy in aquifers has recently received considerable attention as a means to conserve and more efficiently use energy supplies. The analysis of aquifer thermal energy storage (ATES) systems will rely on the results from mathematical and geochemical models. Therefore, the state-of-the-art models relevant to ATES was reviewed and evaluated. These models describe important processes active in ATES including ground-water flow, heat transport (heat flow), solute transport (movement of contaminants), and geochemical reactions. In general, available models of the saturated ground-water environment are adequate to address most concerns associated with ATES; that is, design, operation, and environmental assessment. In those cases where models are not adequate, development should be preceded by efforts to identify significant physical phenomena and relate model parameters to measurable quantities. Model development can then proceed with the expectation of an adequate data base existing for the model's eventual use. Review of model applications to ATES shows that the major emphasis has been on generic sensitivity analysis and site characterization. Assuming that models are applied appropriately, the primary limitation on model calculations is the data base used to construct the model. Numerical transport models are limited by the uncertainty of subsurface data and the lack of long-term historical data for calibration. Geochemical models are limited by the lack of thermodynamic data for the temperature ranges applicable to ATES. Model applications undertaken with data collection activities on ATES sites should provide the most important contributions to the understanding and utilization of ATES. Therefore, the primary conclusion of this review is that model application to field sites in conjunction with data collection activities is essential to the development of this technology.

  10. Evaluation of risk and benefit in thermal effusivity sensor for monitoring lubrication process in pharmaceutical product manufacturing.

    Science.gov (United States)

    Uchiyama, Jumpei; Kato, Yoshiteru; Uemoto, Yoshifumi

    2014-08-01

    In the process design of tablet manufacturing, understanding and control of the lubrication process is important from various viewpoints. A detailed analysis of thermal effusivity data in the lubrication process was conducted in this study. In addition, we evaluated the risk and benefit in the lubrication process by a detailed investigation. It was found that monitoring of thermal effusivity detected mainly the physical change of bulk density, which was changed by dispersal of the lubricant and the coating powder particle by the lubricant. The monitoring of thermal effusivity was almost the monitoring of bulk density, thermal effusivity could have a high correlation with tablet hardness. Moreover, as thermal effusivity sensor could detect not only the change of the conventional bulk density but also the fractional change of thermal conductivity and thermal capacity, two-phase progress of lubrication process could be revealed. However, each contribution of density, thermal conductivity, or heat capacity to thermal effusivity has the risk of fluctuation by formulation. After carefully considering the change factor with the risk to be changed by formulation, thermal effusivity sensor can be a useful tool for monitoring as process analytical technology, estimating tablet hardness and investigating the detailed mechanism of the lubrication process.

  11. New sensor and non-contact geometrical survey for the vibrating wire technique

    Energy Technology Data Exchange (ETDEWEB)

    Geraldes, Renan [Brazilian Synchrotron Light Laboratory (LNLS), Campinas, SP (Brazil); Junqueira Leão, Rodrigo, E-mail: rodrigo.leao@lnls.br [Brazilian Synchrotron Light Laboratory (LNLS), Campinas, SP (Brazil); Cernicchiaro, Geraldo [Brazilian Center for Research in Physics (CBPF), Rio de Janeiro, RJ (Brazil); Terenzi Neuenschwander, Regis; Citadini, James Francisco; Droher Rodrigues, Antônio Ricardo [Brazilian Synchrotron Light Laboratory (LNLS), Campinas, SP (Brazil)

    2016-03-01

    The tolerances for the alignment of the magnets in the girders of the next machine of the Brazilian Synchrotron Light Laboratory (LNLS), Sirius, are as small as 40 µm for translations and 0.2 mrad for rotations. Therefore, a novel approach to the well-known vibrating wire technique has been developed and tested for the precise fiducialization of magnets. The alignment bench consists of four commercial linear stages, a stretched wire, a commercial lock-in amplifier working with phase-locked loop (PLL), a coordinate measuring machine (CMM) and a vibration sensor for the wire. This novel sensor has been designed for a larger linear region of operation. For the mechanical metrology step of the fiducialization of quadrupoles an innovative technique, using the vision system of the CMM, is presented. While the work with pitch and yaw orientations is still ongoing with promising partial results, the system already presents an uncertainty level below 10 µm for translational alignment.

  12. Location estimation in wireless sensor networks using spring-relaxation technique.

    Science.gov (United States)

    Zhang, Qing; Foh, Chuan Heng; Seet, Boon-Chong; Fong, A C M

    2010-01-01

    Accurate and low-cost autonomous self-localization is a critical requirement of various applications of a large-scale distributed wireless sensor network (WSN). Due to its massive deployment of sensors, explicit measurements based on specialized localization hardware such as the Global Positioning System (GPS) is not practical. In this paper, we propose a low-cost WSN localization solution. Our design uses received signal strength indicators for ranging, light weight distributed algorithms based on the spring-relaxation technique for location computation, and the cooperative approach to achieve certain location estimation accuracy with a low number of nodes with known locations. We provide analysis to show the suitability of the spring-relaxation technique for WSN localization with cooperative approach, and perform simulation experiments to illustrate its accuracy in localization.

  13. Location Estimation in Wireless Sensor Networks Using Spring-Relaxation Technique

    Directory of Open Access Journals (Sweden)

    Qing Zhang

    2010-05-01

    Full Text Available Accurate and low-cost autonomous self-localization is a critical requirement of various applications of a large-scale distributed wireless sensor network (WSN. Due to its massive deployment of sensors, explicit measurements based on specialized localization hardware such as the Global Positioning System (GPS is not practical. In this paper, we propose a low-cost WSN localization solution. Our design uses received signal strength indicators for ranging, light weight distributed algorithms based on the spring-relaxation technique for location computation, and the cooperative approach to achieve certain location estimation accuracy with a low number of nodes with known locations. We provide analysis to show the suitability of the spring-relaxation technique for WSN localization with cooperative approach, and perform simulation experiments to illustrate its accuracy in localization.

  14. Non-destructive high-resolution thermal imaging techniques to evaluate wildlife and delicate biological samples

    International Nuclear Information System (INIS)

    Lavers, C; Franklin, P; Franklin, P; Plowman, A; Sayers, G; Bol, J; Shepard, D; Fields, D

    2009-01-01

    Thermal imaging cameras now allows routine monitoring of dangerous yet endangered wildlife in captivity. This study looks at the potential applications of radiometrically calibrated thermal data to wildlife, as well as providing parameters for future materials applications. We present a non-destructive active testing technique suitable for enhancing imagery contrast of thin or delicate biological specimens yielding improved thermal contrast at room temperature, for analysis of sample thermal properties. A broad spectrum of animals is studied with different textured surfaces, reflective and emissive properties in the infra red part of the electromagnetic spectrum. Some surface features offer biomimetic materials design opportunities.

  15. Non-destructive high-resolution thermal imaging techniques to evaluate wildlife and delicate biological samples

    Energy Technology Data Exchange (ETDEWEB)

    Lavers, C; Franklin, P; Franklin, P; Plowman, A; Sayers, G; Bol, J; Shepard, D; Fields, D, E-mail: brnc-radarcomms1@nrta.mod.u [Sensors Team, Plymouth University at Britannia Royal Naval College, Dartmouth, Devon (United Kingdom) and Paignton Zoological Park, Paignton, Devon (United Kingdom); Thermal Wave Imaging, Inc., 845 Livernoise St, Ferndale, MI (United States); Buckfast Butterfly and Otter Sanctuary, Buckfast, Devon (United Kingdom)

    2009-07-01

    Thermal imaging cameras now allows routine monitoring of dangerous yet endangered wildlife in captivity. This study looks at the potential applications of radiometrically calibrated thermal data to wildlife, as well as providing parameters for future materials applications. We present a non-destructive active testing technique suitable for enhancing imagery contrast of thin or delicate biological specimens yielding improved thermal contrast at room temperature, for analysis of sample thermal properties. A broad spectrum of animals is studied with different textured surfaces, reflective and emissive properties in the infra red part of the electromagnetic spectrum. Some surface features offer biomimetic materials design opportunities.

  16. High-performance thermal cutting techniques for underwater use

    International Nuclear Information System (INIS)

    Bach, F.W.

    2002-01-01

    Over the past few years, the Institute for Materials Research of the University of Hanover developed a new product family (Contact-Arc-Metal-X) of electrothermal techniques for underwater cutting of metal structures. This CAMX technology comprises contact arc metal cutting by means of a sword-shaped electrode, contact arc metal grinding with a rotating electrode, and contact arc metal drilling with an integrated interlocking mechanism. CAMC is characterized by its capability to cut components with complex structures. Undercuts and cavities constitute no obstacles in the process. CAMG is a technique for straight cutting characterized by its high cutting speeds. CAMD is able to produce countersunk boreholes and holes of any geometry. The integrated tensioning mechanism allows parts to be gripped and transported which could not be handled by conventional gripper systems. (orig.) [de

  17. Application of novel hall sensor technique to evaluate internal defect nondestructively in squirrel cage rotor

    International Nuclear Information System (INIS)

    Park, Myung Ju; Lee, Joon Hyun

    1998-01-01

    Development of Nondestructive Tester for industrial application to detect flaws in aluminum die-casted squirrel case rotor is reported in this paper. Electronic currents are supplied to the end-ring and Hall effect sensors are used to detect the variation of currents which flow in the bar of the rotor. Some signal processing techniques are introduced to classify the signals due to the defects in the bars

  18. Improved Thermal-Vacuum Compatible Flat Plate Radiometric Source For System-Level Testing Of Optical Sensors

    Science.gov (United States)

    Schwarz, Mark A.; Kent, Craig J.; Bousquet, Robert; Brown, Steven W.

    2016-01-01

    In this work, we describe an improved thermal-vacuum compatible flat plate radiometric source which has been developed and utilized for the characterization and calibration of remote optical sensors. This source is unique in that it can be used in situ, in both ambient and thermal-vacuum environments, allowing it to follow the sensor throughout its testing cycle. The performance of the original flat plate radiometric source was presented at the 2009 SPIE1. Following the original efforts, design upgrades were incorporated into the source to improve both radiometric throughput and uniformity. The pre-thermal-vacuum (pre-TVAC) testing results of a spacecraft-level optical sensor with the improved flat plate illumination source, both in ambient and vacuum environments, are presented. We also briefly discuss potential FPI configuration changes in order to improve its radiometric performance.

  19. Thermal/structural/optical integrated design for optical sensor mounted on unmanned aerial vehicle

    Science.gov (United States)

    Zhang, Gaopeng; Yang, Hongtao; Mei, Chao; Wu, Dengshan; Shi, Kui

    2016-01-01

    With the rapid development of science and technology and the promotion of many local wars in the world, altitude optical sensor mounted on unmanned aerial vehicle is more widely applied in the airborne remote sensing, measurement and detection. In order to obtain high quality image of the aero optical remote sensor, it is important to analysis its thermal-optical performance on the condition of high speed and high altitude. Especially for the key imaging assembly, such as optical window, the temperature variation and temperature gradient can result in defocus and aberrations in optical system, which will lead to the poor quality image. In order to improve the optical performance of a high speed aerial camera optical window, the thermal/structural/optical integrated design method is developed. Firstly, the flight environment of optical window is analyzed. Based on the theory of aerodynamics and heat transfer, the convection heat transfer coefficient is calculated. The temperature distributing of optical window is simulated by the finite element analysis software. The maximum difference in temperature of the inside and outside of optical window is obtained. Then the deformation of optical window under the boundary condition of the maximum difference in temperature is calculated. The optical window surface deformation is fitted in Zernike polynomial as the interface, the calculated Zernike fitting coefficients is brought in and analyzed by CodeV Optical Software. At last, the transfer function diagrams of the optical system on temperature field are comparatively analyzed. By comparing and analyzing the result, it can be obtained that the optical path difference caused by thermal deformation of the optical window is 138.2 nm, which is under PV ≤1 4λ . The above study can be used as an important reference for other optical window designs.

  20. Sensitivity studies on the multi-sensor conductivity probe measurement technique for two-phase flows

    Energy Technology Data Exchange (ETDEWEB)

    Worosz, Ted [Department of Mechanical and Nuclear Engineering, The Pennsylvania State University, 230 Reber Building, University Park, PA 16802 (United States); Bernard, Matt [The United States Nuclear Regulatory Commission, 11545 Rockville Pike, Rockville, MD 20852 (United States); Kong, Ran; Toptan, Aysenur [Department of Mechanical and Nuclear Engineering, The Pennsylvania State University, 230 Reber Building, University Park, PA 16802 (United States); Kim, Seungjin, E-mail: skim@psu.edu [Department of Mechanical and Nuclear Engineering, The Pennsylvania State University, 230 Reber Building, University Park, PA 16802 (United States); Hoxie, Chris [The United States Nuclear Regulatory Commission, 11545 Rockville Pike, Rockville, MD 20852 (United States)

    2016-12-15

    Highlights: • Revised conductivity probe circuit to eliminate signal “ghosting” among sensors. • Higher sampling frequencies suggested for bubble number frequency and a{sub i} measurements. • Two-phase parameter sensitivity to measurement duration and bubble number investigated. • Sensors parallel to pipe wall recommended for symmetric bubble velocity measurements. • Sensor separation distance ratio (s/d) greater than four minimizes bubble velocity error. - Abstract: The objective of this study is to advance the local multi-sensor conductivity probe measurement technique through systematic investigation into several practical aspects of a conductivity probe measurement system. Firstly, signal “ghosting” among probe sensors is found to cause artificially high bubble velocity measurements and low interfacial area concentration (a{sub i}) measurements that depend on sampling frequency and sensor impedance. A revised electrical circuit is suggested to eliminate this artificial variability. Secondly, the sensitivity of the probe measurements to sampling frequency is investigated in 13 two-phase flow conditions with superficial liquid and gas velocities ranging from 1.00–5.00 m/s and 0.17–2.0 m/s, respectively. With increasing gas flow rate, higher sampling frequencies, greater than 100 kHz in some cases, are required to adequately capture the bubble number frequency and a{sub i} measurements. This trend is due to the increase in gas velocity and the transition to the slug flow regime. Thirdly, the sensitivity of the probe measurements to the measurement duration as well as the sample number is investigated for the same flow conditions. Measurements of both group-I (spherical/distorted) and group-II (cap/slug/churn-turbulent) bubbles are found to be relatively insensitive to both the measurement duration and the number of bubbles, as long as the measurements are made for a duration long enough to capture a collection of samples characteristic to a

  1. An Autonomous Self-Aware and Adaptive Fault Tolerant Routing Technique for Wireless Sensor Networks.

    Science.gov (United States)

    Abba, Sani; Lee, Jeong-A

    2015-08-18

    We propose an autonomous self-aware and adaptive fault-tolerant routing technique (ASAART) for wireless sensor networks. We address the limitations of self-healing routing (SHR) and self-selective routing (SSR) techniques for routing sensor data. We also examine the integration of autonomic self-aware and adaptive fault detection and resiliency techniques for route formation and route repair to provide resilience to errors and failures. We achieved this by using a combined continuous and slotted prioritized transmission back-off delay to obtain local and global network state information, as well as multiple random functions for attaining faster routing convergence and reliable route repair despite transient and permanent node failure rates and efficient adaptation to instantaneous network topology changes. The results of simulations based on a comparison of the ASAART with the SHR and SSR protocols for five different simulated scenarios in the presence of transient and permanent node failure rates exhibit a greater resiliency to errors and failure and better routing performance in terms of the number of successfully delivered network packets, end-to-end delay, delivered MAC layer packets, packet error rate, as well as efficient energy conservation in a highly congested, faulty, and scalable sensor network.

  2. An Autonomous Self-Aware and Adaptive Fault Tolerant Routing Technique for Wireless Sensor Networks

    Science.gov (United States)

    Abba, Sani; Lee, Jeong-A

    2015-01-01

    We propose an autonomous self-aware and adaptive fault-tolerant routing technique (ASAART) for wireless sensor networks. We address the limitations of self-healing routing (SHR) and self-selective routing (SSR) techniques for routing sensor data. We also examine the integration of autonomic self-aware and adaptive fault detection and resiliency techniques for route formation and route repair to provide resilience to errors and failures. We achieved this by using a combined continuous and slotted prioritized transmission back-off delay to obtain local and global network state information, as well as multiple random functions for attaining faster routing convergence and reliable route repair despite transient and permanent node failure rates and efficient adaptation to instantaneous network topology changes. The results of simulations based on a comparison of the ASAART with the SHR and SSR protocols for five different simulated scenarios in the presence of transient and permanent node failure rates exhibit a greater resiliency to errors and failure and better routing performance in terms of the number of successfully delivered network packets, end-to-end delay, delivered MAC layer packets, packet error rate, as well as efficient energy conservation in a highly congested, faulty, and scalable sensor network. PMID:26295236

  3. Research on Wushu Actions and Techniques Based on a Biomechanical Sensor System

    Directory of Open Access Journals (Sweden)

    Xiaohong Wang

    2017-06-01

    Full Text Available Wushu actions and techniques is an index reflecting the differences in physical quality, basic skills and performance level between athletes. But the gap narrows because of the rapid development of sports events with high difficulty and aesthetic values. Thus, it is urgent to improve Wushu techniques and create new ones. This study measured and quantitatively analyzed Wushu actions and techniques using a biomechanical sensor and biomechanical theory, aiming to provide scientific guidance and technical support for the promotion and improvement of Wushu level and the enhancement of the visual sense and competitiveness of Wushu. In the study, the plantar pressure of a flying kick was measured using a Polyvinylidene Fluoride (PVDF insole plantar pressure sensor. The data analysis suggested that the heel had little influence on take-off jumping and the load borne by the sole was the largest, which provided a quantitative basis for the innovation and beautification of the take-off action of the jumping kick and also suggested the design of the plantar pressure sensor was reasonable and feasible.

  4. Development of Processing Techniques for Advanced Thermal Protection Materials

    Science.gov (United States)

    Selvaduray, Guna; Cox, Michael; Srinivasan, Vijayakumar

    1997-01-01

    Thermal Protection Materials Branch (TPMB) has been involved in various research programs to improve the properties and structural integrity of the existing aerospace high temperature materials. Specimens from various research programs were brought into the analytical laboratory for the purpose of obtaining and refining the material characterization. The analytical laboratory in TPMB has many different instruments which were utilized to determine the physical and chemical characteristics of materials. Some of the instruments that were utilized by the SJSU students are: Scanning Electron Microscopy (SEM), Energy Dispersive X-ray analysis (EDX), X-ray Diffraction Spectrometer (XRD), Fourier Transform-Infrared Spectroscopy (FTIR), Ultra Violet Spectroscopy/Visible Spectroscopy (UV/VIS), Particle Size Analyzer (PSA), and Inductively Coupled Plasma Atomic Emission Spectrometer (ICP-AES). The above mentioned analytical instruments were utilized in the material characterization process of the specimens from research programs such as: aerogel ceramics (I) and (II), X-33 Blankets, ARC-Jet specimens, QUICFIX specimens and gas permeability of lightweight ceramic ablators. In addition to analytical instruments in the analytical laboratory at TPMB, there are several on-going experiments. One particular experiment allows the measurement of permeability of ceramic ablators. From these measurements, physical characteristics of the ceramic ablators can be derived.

  5. Study of Lactic Acid Thermal Behavior Using Thermoanalytical Techniques

    Directory of Open Access Journals (Sweden)

    Andrea Komesu

    2017-01-01

    Full Text Available Actually, there is a growing interest in the biotechnological production of lactic acid by fermentation aiming to substitute fossil fuel routes. The development of an efficient method for its separation and purification from fermentation broth is very important to assure the economic viability of production. Due to its high reactivity and tendency to decompose at high temperatures, the study of lactic acid thermal behavior is essential for its separation processes and potential application. In the present study, differential scanning calorimetry (DSC analyses showed endothermic peaks related to the process of evaporation. Data of thermogravimetry (TG/DTG were correlated to Arrhenius and Kissinger equations to provide the evaporation kinetic parameters and used to determine the vaporization enthalpy. Activation energies were 51.08 and 48.37 kJ·mol−1 and frequency values were 859.97 and 968.81 s−1 obtained by Arrhenius and Kissinger equations, respectively. Thermogravimetry, coupled with mass spectroscopy (TG-MS, provided useful information about decomposition products when lactic acid was heated at 573 K for approximately 30 min.

  6. Evaluation of Candidate In-Pile Thermal Conductivity Techniques

    International Nuclear Information System (INIS)

    Fox, B.; Ban, H.; Daw, J.; Condie, K.; Knudson, D.; Rempe, J.

    2009-01-01

    Thermophysical properties of materials must be known for proper design, test, and application of new fuels and structural properties in nuclear reactors. In the case of nuclear fuels during irradiation, the physical structure and chemical composition change as a function of time and position within the rod. Typically, thermal conductivity changes, as well as other thermophysical properties being evaluated during irradiation in a materials and test reactor, are measured out-of-pile in 'hot-cells'. Repeatedly removing samples from a test reactor to make out-of-pile measurements is expensive, has the potential to disturb phenomena of interest, and only provide understanding of the sample's end state at the time each measurement is made. There are also limited thermophysical property data for advanced fuels. Such data are needed for the development of next generation reactors and advanced fuels for existing nuclear plants. Having the capacity to effectively and quickly characterize fuels and material properties during irradiation has the potential to improve the fidelity of nuclear fuel data and reduce irradiation testing costs

  7. Thermal Diffusivity Measurement for p-Si and Ag/p-Si by Photoacoustic Technique

    Science.gov (United States)

    Hussein, Mohammed Jabbar; Yunus, W. Mahmood Mat; Kamari, Halimah Mohamed; Zakaria, Azmi

    2015-10-01

    Thermal diffusivity (TD) of p-Si and Ag/p-Si samples were measured by photoacoustic technique using open photoacoustic cell (OPC). The samples were annealed by heating them at 960, 1050, 1200, and 1300 °C for 3 h in air. The thermal diffusivity of Ag-coated samples was obtained by fitting the photoacoustic experimental data to the thermally thick equation for Rosencwaig and Gersho (RG) theory. For the single layer samples, the thermal diffusivity can be obtained by fitting as well as by obtaining the critical frequency f c . In this study, the thermal diffusivity of the p-Si samples increased with increasing the annealing temperature. The thermal diffusivity of the Ag/p-Si samples, after reaching the maximum value of about 2.73 cm2/s at a temperature of 1200 °C, decreased due to the silver complete melt in the surface of the silicon.

  8. Advanced kinetics for calorimetric techniques and thermal stability screening of sulfide minerals

    International Nuclear Information System (INIS)

    Iliyas, Abduljelil; Hawboldt, Kelly; Khan, Faisal

    2010-01-01

    Thermal methods of analysis such as differential scanning calorimetry (DSC) provide a powerful methodology for the study of solid reactions. This paper proposes an improved thermal analysis methodology for thermal stability investigation of complex solid-state reactions. The proposed methodology is based on differential iso-conversional approach and involves peak separation, individual peak analysis and combination of isothermal/non-isothermal DSC measurements for kinetic analysis and prediction. The proposed thermal analysis, which coupled with Mineral Libration Analyzer (MLA) technique was employed to investigate thermal behavior of sulfide mineral oxidation. The importance of various experimental variables such as particle size, heating rate and atmosphere were investigated and discussed. The information gained from such an advanced thermal analysis method is useful for scale-up processes with potential of significant savings in plant operations, as well as in mitigating adverse environmental and safety issues arising from handling and storage of sulfide minerals.

  9. Thermal diffusivity measurement for p-Si and Ag/p-Si by photoacoustic technique

    Energy Technology Data Exchange (ETDEWEB)

    Hussein, Mohammed Jabbar; Yunus, W. Mahmood Mat; Kamari, Halimah Mohamed; Zakaria, Azmi, E-mail: mohammed55865@yahoo.com [Department of Physics, Faculty of Science, Universiti PutraMalaysia (UPM), Serdang (Malaysia)

    2015-10-15

    Thermal diffusivity (TD) of p-Si and Ag/p-Si samples were measured by photoacoustic technique using open photoacoustic cell (OPC). The samples were annealed by heating them at 960, 1050, 1200, and 1300 °C for 3 h in air. The thermal diffusivity of Ag-coated samples was obtained by fitting the photoacoustic experimental data to the thermally thick equation for Rosencwaig and Gersho (RG) theory. For the single layer samples, the thermal diffusivity can be obtained by fitting as well as by obtaining the critical frequency f{sub c.} In this study, the thermal diffusivity of the p-Si samples increased with increasing the annealing temperature. The thermal diffusivity of the Ag/p-Si samples, after reaching the maximum value of about 2.73 cm{sup 2}/s at a temperature of 1200 °C, decreased due to the silver complete melt in the surface of the silicon. (author)

  10. Clock-Frequency Switching Technique for Energy Saving of Microcontroller Unit (MCU-Based Sensor Node

    Directory of Open Access Journals (Sweden)

    Pumin Duangmanee

    2018-05-01

    Full Text Available In this paper; a technique is proposed for reducing the energy consumption of microcontroller-based sensor nodes by switching the operating clock between low and high frequencies. The proposed concept is motivated by the fact that if the application codes of the microcontroller unit (MCU consist of no-wait state instruction sets, it consumes less energy when it operates with a higher frequency. When the application code of the MCU consists of wait instruction sets; e.g., a wait acknowledge signal, it switches to low clock frequency. The experimental results confirm that the proposed technique can reduce the MCU energy consumption up to 66.9%.

  11. High-precision numerical simulation with autoadaptative grid technique in nonlinear thermal diffusion

    International Nuclear Information System (INIS)

    Chambarel, A.; Pumborios, M.

    1992-01-01

    This paper reports that many engineering problems concern the determination of a steady state solution in the case with strong thermal gradients, and results obtained using the finite-element technique are sometimes inaccurate, particularly for nonlinear problems with unadapted meshes. Building on previous results in linear problems, we propose an autoadaptive technique for nonlinear cases that uses quasi-Newtonian iterations to reevaluate an interpolation error estimation. The authors perfected an automatic refinement technique to solve the nonlinear thermal problem of temperature calculus in a cast-iron cylinder head of a diesel engine

  12. Multispectral Terrain Background Simulation Techniques For Use In Airborne Sensor Evaluation

    Science.gov (United States)

    Weinberg, Michael; Wohlers, Ronald; Conant, John; Powers, Edward

    1988-08-01

    A background simulation code developed at Aerodyne Research, Inc., called AERIE is designed to reflect the major sources of clutter that are of concern to staring and scanning sensors of the type being considered for various airborne threat warning (both aircraft and missiles) sensors. The code is a first principles model that could be used to produce a consistent image of the terrain for various spectral bands, i.e., provide the proper scene correlation both spectrally and spatially. The code utilizes both topographic and cultural features to model terrain, typically from DMA data, with a statistical overlay of the critical underlying surface properties (reflectance, emittance, and thermal factors) to simulate the resulting texture in the scene. Strong solar scattering from water surfaces is included with allowance for wind driven surface roughness. Clouds can be superimposed on the scene using physical cloud models and an analytical representation of the reflectivity obtained from scattering off spherical particles. The scene generator is augmented by collateral codes that allow for the generation of images at finer resolution. These codes provide interpolation of the basic DMA databases using fractal procedures that preserve the high frequency power spectral density behavior of the original scene. Scenes are presented illustrating variations in altitude, radiance, resolution, material, thermal factors, and emissivities. The basic models utilized for simulation of the various scene components and various "engineering level" approximations are incorporated to reduce the computational complexity of the simulation.

  13. Laser/fluorescent dye flow visualization technique developed for system component thermal hydraulic studies

    International Nuclear Information System (INIS)

    Oras, J.J.; Kasza, K.E.

    1988-01-01

    A novel laser flow visualization technique is presented together with examples of its use in visualizing complex flow patterns and plans for its further development. This technique has been successfully used to study (1) the flow in a horizontal pipe subject to temperature transients, to view the formation and breakup of thermally stratified flow and to determine instantaneous velocity distributions in the same flow at various axial locations; (2) the discharge of a stratified pipe flow into a plenum exhibiting a periodic vortex pattern; and (3) the thermal-buoyancy-induced flow channeling on the shell side of a heat exchanger with glass tubes and shell. This application of the technique to heat exchangers is unique. The flow patterns deep within a large tube bundle can be studied under steady or transient conditions. This laser flow visualization technique constitutes a very powerful tool for studying single or multiphase flows in complex thermal system components

  14. Work in progress. Transcatheter thermal venous occlusion: a new technique

    International Nuclear Information System (INIS)

    Rholl, K.S.; Rysavy, J.A.; Vlodaver, Z.; Cragg, A.H.; Castaneda-Zuniga, W.R.; Amplatz, K.

    1982-01-01

    Diatrizoate (76%) contrast agent heated to 100 0 C was injected into the veins of dogs and one human volunteer for the nonsurgical occlusion of the vessels. Follow-up venograms and histologic examinations, at intervals varying from one day to four weeks later, revealed thrombosis of the injected veins in all animals. Thrombosis occurred one to five days after injection of contrast agent. The authors conclude that hot contrast medium is a safe and convenient agent for inducing thrombosis. It is much easier to use than mechanical devices, tissue glues, and plastics, which involve complex procedures and specialized equipment. In contrast to other sclerosing agents, hot contrast agent is rapidly converted into a nonsclerosing agent by cooling. The new technique allows a more controlled thremal injury to the vascular wall and is under fluoroscopic control

  15. Measurement of Thermal Properties of Triticale Starch Films Using Photothermal Techniques

    Science.gov (United States)

    Correa-Pacheco, Z. N.; Cruz-Orea, A.; Jiménez-Pérez, J. L.; Solorzano-Ojeda, S. C.; Tramón-Pregnan, C. L.

    2015-06-01

    Nowadays, several commercially biodegradable materials have been developed with mechanical properties similar to those of conventional petrochemical-based polymers. These materials are made from renewable sources such as starch, cellulose, corn, and molasses, being very attractive for numerous applications in the plastics, food, and paper industries, among others. Starches from maize, rice, wheat, and potato are used in the food industry. However, other types of starches are not used due to their low protein content, such as triticale. In this study, starch films, processed using a single screw extruder with different compositions, were thermally and structurally characterized. The thermal diffusivity, thermal effusivity, and thermal conductivity of the biodegradable films were determined using photothermal techniques. The thermal diffusivity was measured using the open photoacoustic cell technique, and the thermal effusivity was obtained by the photopyroelectric technique in an inverse configuration. The results showed differences in thermal properties for the films. Also, the films microstructures were observed by scanning electron microscopy, transmission electron microscopy, and the crystalline structure determined by X-ray diffraction.

  16. Localization in Wireless Sensor Networks: A Survey on Algorithms, Measurement Techniques, Applications and Challenges

    Directory of Open Access Journals (Sweden)

    Anup Kumar Paul

    2017-10-01

    Full Text Available Localization is an important aspect in the field of wireless sensor networks (WSNs that has developed significant research interest among academia and research community. Wireless sensor network is formed by a large number of tiny, low energy, limited processing capability and low-cost sensors that communicate with each other in ad-hoc fashion. The task of determining physical coordinates of sensor nodes in WSNs is known as localization or positioning and is a key factor in today’s communication systems to estimate the place of origin of events. As the requirement of the positioning accuracy for different applications varies, different localization methods are used in different applications and there are several challenges in some special scenarios such as forest fire detection. In this paper, we survey different measurement techniques and strategies for range based and range free localization with an emphasis on the latter. Further, we discuss different localization-based applications, where the estimation of the location information is crucial. Finally, a comprehensive discussion of the challenges such as accuracy, cost, complexity, and scalability are given.

  17. A Comparison of Alternative Distributed Dynamic Cluster Formation Techniques for Industrial Wireless Sensor Networks.

    Science.gov (United States)

    Gholami, Mohammad; Brennan, Robert W

    2016-01-06

    In this paper, we investigate alternative distributed clustering techniques for wireless sensor node tracking in an industrial environment. The research builds on extant work on wireless sensor node clustering by reporting on: (1) the development of a novel distributed management approach for tracking mobile nodes in an industrial wireless sensor network; and (2) an objective comparison of alternative cluster management approaches for wireless sensor networks. To perform this comparison, we focus on two main clustering approaches proposed in the literature: pre-defined clusters and ad hoc clusters. These approaches are compared in the context of their reconfigurability: more specifically, we investigate the trade-off between the cost and the effectiveness of competing strategies aimed at adapting to changes in the sensing environment. To support this work, we introduce three new metrics: a cost/efficiency measure, a performance measure, and a resource consumption measure. The results of our experiments show that ad hoc clusters adapt more readily to changes in the sensing environment, but this higher level of adaptability is at the cost of overall efficiency.

  18. Performance Analysis of the Microsoft Kinect Sensor for 2D Simultaneous Localization and Mapping (SLAM Techniques

    Directory of Open Access Journals (Sweden)

    Kamarulzaman Kamarudin

    2014-12-01

    Full Text Available This paper presents a performance analysis of two open-source, laser scanner-based Simultaneous Localization and Mapping (SLAM techniques (i.e., Gmapping and Hector SLAM using a Microsoft Kinect to replace the laser sensor. Furthermore, the paper proposes a new system integration approach whereby a Linux virtual machine is used to run the open source SLAM algorithms. The experiments were conducted in two different environments; a small room with no features and a typical office corridor with desks and chairs. Using the data logged from real-time experiments, each SLAM technique was simulated and tested with different parameter settings. The results show that the system is able to achieve real time SLAM operation. The system implementation offers a simple and reliable way to compare the performance of Windows-based SLAM algorithm with the algorithms typically implemented in a Robot Operating System (ROS. The results also indicate that certain modifications to the default laser scanner-based parameters are able to improve the map accuracy. However, the limited field of view and range of Kinect’s depth sensor often causes the map to be inaccurate, especially in featureless areas, therefore the Kinect sensor is not a direct replacement for a laser scanner, but rather offers a feasible alternative for 2D SLAM tasks.

  19. Novel Hybrid Scheduling Technique for Sensor Nodes with Mixed Criticality Tasks

    Directory of Open Access Journals (Sweden)

    Mihai-Victor Micea

    2017-06-01

    Full Text Available Sensor networks become increasingly a key technology for complex control applications. Their potential use in safety- and time-critical domains has raised the need for task scheduling mechanisms specially adapted to sensor node specific requirements, often materialized in predictable jitter-less execution of tasks characterized by different criticality levels. This paper offers an efficient scheduling solution, named Hybrid Hard Real-Time Scheduling (H2RTS, which combines a static, clock driven method with a dynamic, event driven scheduling technique, in order to provide high execution predictability, while keeping a high node Central Processing Unit (CPU utilization factor. From the detailed, integrated schedulability analysis of the H2RTS, a set of sufficiency tests are introduced and demonstrated based on the processor demand and linear upper bound metrics. The performance and correct behavior of the proposed hybrid scheduling technique have been extensively evaluated and validated both on a simulator and on a sensor mote equipped with ARM7 microcontroller.

  20. WRHT: A Hybrid Technique for Detection of Wormhole Attack in Wireless Sensor Networks

    Directory of Open Access Journals (Sweden)

    Rupinder Singh

    2016-01-01

    Full Text Available Wormhole attack is a challenging security threat to wireless sensor networks which results in disrupting most of the routing protocols as this attack can be triggered in different modes. In this paper, WRHT, a wormhole resistant hybrid technique, is proposed, which can detect the presence of wormhole attack in a more optimistic manner than earlier techniques. WRHT is based on the concept of watchdog and Delphi schemes and ensures that the wormhole will not be left untreated in the sensor network. WRHT makes use of the dual wormhole detection mechanism of calculating probability factor time delay probability and packet loss probability of the established path in order to find the value of wormhole presence probability. The nodes in the path are given different ranking and subsequently colors according to their behavior. The most striking feature of WRHT consists of its capacity to defend against almost all categories of wormhole attacks without depending on any required additional hardware such as global positioning system, timing information or synchronized clocks, and traditional cryptographic schemes demanding high computational needs. The experimental results clearly indicate that the proposed technique has significant improvement over the existing wormhole attack detection techniques.

  1. Comparative study of linear and nonlinear ultrasonic techniques for evaluation thermal damage of tube like structures

    International Nuclear Information System (INIS)

    Li, Weibin; Cho, Younho; Li, Xianqiang

    2013-01-01

    Ultrasonic guided wave techniques have been widely used for long range nondestructive detection in tube like structures. The present paper investigates the ultrasonic linear and nonlinear parameters for evaluating the thermal damage in aluminum pipe. Specimens were subjected to thermal loading. Flexible polyvinylidene fluoride (PVDF) comb transducers were used to generate and receive the ultrasonic waves. The second harmonic wave generation technique was used to check the material nonlinearity change after different heat loadings. The conventional linear ultrasonic approach based on attenuation was also used to evaluate the thermal damages in specimens. The results show that the proposed experimental setup is viable to assess the thermal damage in an aluminum pipe. The ultrasonic nonlinear parameter is a promising candidate for the prediction of micro damages in a tube like structure

  2. Plasma diagnostic techniques in thermal-barrier tandem-mirror fusion experiments

    International Nuclear Information System (INIS)

    Silver, E.H.; Clauser, J.F.; Carter, M.R.; Failor, B.H.; Foote, J.H.; Hornady, R.S.; James, R.A.; Lasnier, C.J.; Perkins, D.E.

    1986-01-01

    We review two classes of plasma diagnostic techniques used in thermal-barrier tandem-mirror fusion experiments. The emphasis of the first class is to study mirror-trapped electrons at the thermal-barrier location. The focus of the second class is to measure the spatial and temporal behavior of the plasma space potential at various axial locations. The design and operation of the instruments in these two categories are discussed and data that are representative of their performance is presented

  3. Thermal characterisation of ceramic/metal joining techniques for fusion applications using X-ray tomography

    Energy Technology Data Exchange (ETDEWEB)

    Evans, Ll.M., E-mail: llion.evans@ccfe.ac.uk [School of Materials, University of Manchester, Grosvenor Street, Manchester M1 7HS (United Kingdom); Margetts, L. [School of Earth, Atmospheric and Environmental Sciences, University of Manchester, Williamson Building, Manchester M13 9PL (United Kingdom); Casalegno, V. [Department of Applied Science and Technology, Politecnico di Torino, Corso Duca degli Abruzzi 24, I-10129 Torino (Italy); Leonard, F.; Lowe, T.; Lee, P.D. [School of Materials, University of Manchester, Grosvenor Street, Manchester M1 7HS (United Kingdom); Schmidt, M.; Mummery, P.M. [School of Mechanical, Aerospace and Civil Engineering (MACE), University of Manchester, Manchester M13 9PL (United Kingdom)

    2014-06-15

    This work investigates the thermal performance of four novel CFC–Cu joining techniques. Two involve direct casting and brazing of Cu onto a chromium modified CFC surface, the other two pre-coat a brazing alloy with chromium using galvanisation and sputtering processes. The chromium carbide layer at the interface has been shown to improve adhesion. Thermal conductivity across the join interface was measured by laser flash analysis. X-ray tomography was performed to investigate micro-structures that might influence the thermal behaviour. It was found that thermal conductivity varied by up to 72%. Quantification of the X-ray tomography data showed that the dominant feature in reducing thermal conductivity was the lateral spread of voids at the interface. Correlations were made to estimate the extent of this effect.

  4. A Temperature-Hardened Sensor Interface with a 12-Bit Digital Output Using a Novel Pulse Width Modulation Technique

    Directory of Open Access Journals (Sweden)

    Emna Chabchoub

    2018-04-01

    Full Text Available A fully integrated sensor interface for a wide operational temperature range is presented. It translates the sensor signal into a pulse width modulated (PWM signal that is then converted into a 12-bit digital output. The sensor interface is based on a pair of injection locked oscillators used to implement a differential time-domain architecture with low sensitivity to temperature variations. A prototype has been fabricated using a 180 nm partially depleted silicon-on-insulator (SOI technology. Experimental results demonstrate a thermal stability as low as 65 ppm/°C over a large temperature range from −20 °C up to 220 °C.

  5. A review of second law techniques applicable to basic thermal science research

    Science.gov (United States)

    Drost, M. Kevin; Zamorski, Joseph R.

    1988-11-01

    This paper reports the results of a review of second law analysis techniques which can contribute to basic research in the thermal sciences. The review demonstrated that second law analysis has a role in basic thermal science research. Unlike traditional techniques, second law analysis accurately identifies the sources and location of thermodynamic losses. This allows the development of innovative solutions to thermal science problems by directing research to the key technical issues. Two classes of second law techniques were identified as being particularly useful. First, system and component investigations can provide information of the source and nature of irreversibilities on a macroscopic scale. This information will help to identify new research topics and will support the evaluation of current research efforts. Second, the differential approach can provide information on the causes and spatial and temporal distribution of local irreversibilities. This information enhances the understanding of fluid mechanics, thermodynamics, and heat and mass transfer, and may suggest innovative methods for reducing irreversibilities.

  6. Synthesis and Thermal Characterization of Hydroxyapatite Powders Obtained by Sol-Gel Technique

    Science.gov (United States)

    Jiménez-Flores, Y.; Camacho, N.; Rojas-Trigos, J. B.; Suárez, M.

    The development of bioactive materials presents an interesting and an extremely relevant problem to solve, in the development of customized cranial and maxillofacial prosthesis, bioactive coating, and cements, for example. In such areas, one of the more employed materials is the synthetic hydroxyapatite, due to its proved biocompatibility with the human body; however, there are few studies about the thermal affinity with the biological surroundings, and most of them are centered in the thermal stability of the hydroxyapatite instead of its transient thermal response. In the present paper, the synthesis and physical-chemical characterization of hydroxyapatite samples, obtained by the sol-gel technique employing ultrasonic mixing, are reported. Employing X-ray diffraction patterns, XEDS and FTIR spectra, the crystal symmetry, chemical elements, and the present functional groups of the studied samples were determined and found to correspond to those reported in the literature, with a stoichiometry close to the ideal for biological applications. Additionally, by means of the photoacoustic detection and infrared photothermal radiometry (IPTR) techniques, the thermal response of the samples was obtained. Analyzing the photoacoustic data, the synthetized samples show photoacoustic opaqueness, responding in the thermally thick regime in the measurement range, and their thermal effusivity was also determined, having values of 1.47 folds the thermal effusivity of the mandibular human bone. Finally, from the IPTR measurements, the thermal diffusivity and thermal conductivity of the samples were also determined, having good agreement with the reported values for synthetic hydroxyapatite. The structural and thermophysical properties of the here reported samples show that the synthesized samples have good thermal affinity with the mandibular human bone tissue, and are suitable for biomedical applications.

  7. Temperature-dependent thermal conductivity of flexible yttria-stabilized zirconia substrate via 3ω technique

    Energy Technology Data Exchange (ETDEWEB)

    Singh, Shivkant; Yarali, Milad; Mavrokefalos, Anastassios [Department of Mechanical Engineering, University of Houston, Houston, TX (United States); Shervin, Shahab [Materials Science and Engineering Program, University of Houston, Houston, TX (United States); Venkateswaran, Venkat; Olenick, Kathy; Olenick, John A. [ENrG Inc., Buffalo, NY (United States); Ryou, Jae-Hyun [Department of Mechanical Engineering, University of Houston, Houston, TX (United States); Materials Science and Engineering Program, University of Houston, Houston, TX (United States); Texas Center for Superconductivity, University of Houston (TcSUH), Houston, TX (United States)

    2017-10-15

    Thermal management in flexible electronic has proven to be challenging thereby limiting the development of flexible devices with high power densities. To truly enable the technological implementation of such devices, it is imperative to develop highly thermally conducting flexible substrates that are fully compatible with large-scale fabrication. Here, we present the thermal conductivity of state-of-the-art flexible yttria-stabilized zirconia (YSZ) substrates measured using the 3ω technique, which is already commercially manufactured via roll-to-roll technique. We observe that increasing the grain size increases the thermal conductivity of the flexible 3 mol.% YSZ, while the flexibility and transparency of the sample are hardly affected by the grain size enlargement. We exhibit thermal conductivity values of up to 4.16 Wm{sup -1}K {sup -1} that is at least 4 times higher than state-of-the-art polymeric flexible substrates. Phonon-hopping model (PHM) for granular material was used to fit the measured thermal conductivity and accurately define the thermal transport mechanism. Our results show that through grain size optimization, YSZ flexible substrates can be realized as flexible substrates, that pave new avenues for future novel application in flexible electronics through the utilization of both their ceramic structural flexibility and high heat dissipating capability. (copyright 2017 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  8. Sensors

    CERN Document Server

    Pigorsch, Enrico

    1997-01-01

    This is the 5th edition of the Metra Martech Directory "EUROPEAN CENTRES OF EXPERTISE - SENSORS." The entries represent a survey of European sensors development. The new edition contains 425 detailed profiles of companies and research institutions in 22 countries. This is reflected in the diversity of sensors development programmes described, from sensors for physical parameters to biosensors and intelligent sensor systems. We do not claim that all European organisations developing sensors are included, but this is a good cross section from an invited list of participants. If you see gaps or omissions, or would like your organisation to be included, please send details. The data base invites the formation of effective joint ventures by identifying and providing access to specific areas in which organisations offer collaboration. This issue is recognised to be of great importance and most entrants include details of collaboration offered and sought. We hope the directory on Sensors will help you to find the ri...

  9. LDMOS Channel Thermometer Based on a Thermal Resistance Sensor for Balancing Temperature in Monolithic Power ICs

    Directory of Open Access Journals (Sweden)

    Tingyou Lin

    2017-06-01

    Full Text Available This paper presents a method of thermal balancing for monolithic power integrated circuits (ICs. An on-chip temperature monitoring sensor that consists of a poly resistor strip in each of multiple parallel MOSFET banks is developed. A temperature-to-frequency converter (TFC is proposed to quantize on-chip temperature. A pulse-width-modulation (PWM methodology is developed to balance the channel temperature based on the quantization. The modulated PWM pulses control the hottest of metal-oxide-semiconductor field-effect transistor (MOSFET bank to reduce its power dissipation and heat generation. A test chip with eight parallel MOSFET banks is fabricated in TSMC 0.25 μm HV BCD processes, and total area is 900 × 914 μm2. The maximal temperature variation among the eight banks can reduce to 2.8 °C by the proposed thermal balancing system from 9.5 °C with 1.5 W dissipation. As a result, our proposed system improves the lifetime of a power MOSFET by 20%.

  10. Development of process data capturing, analysis and controlling for thermal spray techniques - SprayTracker

    Science.gov (United States)

    Kelber, C.; Marke, S.; Trommler, U.; Rupprecht, C.; Weis, S.

    2017-03-01

    Thermal spraying processes are becoming increasingly important in high-technology areas, such as automotive engineering and medical technology. The method offers the advantage of a local layer application with different materials and high deposition rates. Challenges in the application of thermal spraying result from the complex interaction of different influencing variables, which can be attributed to the properties of different materials, operating equipment supply, electrical parameters, flow mechanics, plasma physics and automation. In addition, spraying systems are subject to constant wear. Due to the process specification and the high demands on the produced coatings, innovative quality assurance tools are necessary. A central aspect, which has not yet been considered, is the data management in relation to the present measured variables, in particular the spraying system, the handling system, working safety devices and additional measuring sensors. Both the recording of all process-characterizing variables, their linking and evaluation as well as the use of the data for the active process control presuppose a novel, innovative control system (hardware and software) that was to be developed within the scope of the research project. In addition, new measurement methods and sensors are to be developed and qualified in order to improve the process reliability of thermal spraying.

  11. Alternative technique for biodiesel quality control using an optical fiber long-period grating sensor

    International Nuclear Information System (INIS)

    Falate, Rosane; Nike, Karen; Costa Neto, Pedro Ramos da; Cacao Junior, Eduardo; Muller, Marcia; Kalinowski, Hypolito Jose; Fabris, Jose Luis

    2007-01-01

    We report the use of an optical fiber sensor to measure the soybean oil concentration in samples obtained from the mixture of pure biodiesel and commercial soybean oil. The operation of the device is based on the long-period grating sensitivity to the surrounding medium refractive index, which leads to measurable modifications in the grating transmission spectrum. The proposed analysis method results in errors in the oil concentration of 0.4% and 2.6% for pure biodiesel and commercial soybean oil, respectively. Techniques of total glycerol, dynamic viscosity, density, and hydrogen nuclear magnetic resonance spectroscopy were also employed to validate the proposed method. (author)

  12. An Adaptive Technique for a Redundant-Sensor Navigation System. Ph.D. Thesis

    Science.gov (United States)

    Chien, T. T.

    1972-01-01

    An on-line adaptive technique is developed to provide a self-contained redundant-sensor navigation system with a capability to utilize its full potentiality in reliability and performance. The gyro navigation system is modeled as a Gauss-Markov process, with degradation modes defined as changes in characteristics specified by parameters associated with the model. The adaptive system is formulated as a multistage stochastic process: (1) a detection system, (2) an identification system and (3) a compensation system. It is shown that the sufficient statistics for the partially observable process in the detection and identification system is the posterior measure of the state of degradation, conditioned on the measurement history.

  13. Alternative technique for biodiesel quality control using an optical fiber long-period grating sensor

    Energy Technology Data Exchange (ETDEWEB)

    Falate, Rosane [Universidade Estadual de Ponta Grossa, PR (Brazil). Dept. de Informatica; Nike, Karen; Costa Neto, Pedro Ramos da [Universidade Tecnologica Federal do Parana, Curitiba (Brazil). Dept. de Quimica; Cacao Junior, Eduardo; Muller, Marcia; Kalinowski, Hypolito Jose; Fabris, Jose Luis [Universidade Tecnologica Federal do Parana, Curitiba (Brazil). Dept. de Fisica]. E-mail: fabris@utfpr.edu.br

    2007-07-01

    We report the use of an optical fiber sensor to measure the soybean oil concentration in samples obtained from the mixture of pure biodiesel and commercial soybean oil. The operation of the device is based on the long-period grating sensitivity to the surrounding medium refractive index, which leads to measurable modifications in the grating transmission spectrum. The proposed analysis method results in errors in the oil concentration of 0.4% and 2.6% for pure biodiesel and commercial soybean oil, respectively. Techniques of total glycerol, dynamic viscosity, density, and hydrogen nuclear magnetic resonance spectroscopy were also employed to validate the proposed method. (author)

  14. Process techniques of charge transfer time reduction for high speed CMOS image sensors

    International Nuclear Information System (INIS)

    Cao Zhongxiang; Li Quanliang; Han Ye; Qin Qi; Feng Peng; Liu Liyuan; Wu Nanjian

    2014-01-01

    This paper proposes pixel process techniques to reduce the charge transfer time in high speed CMOS image sensors. These techniques increase the lateral conductivity of the photo-generated carriers in a pinned photodiode (PPD) and the voltage difference between the PPD and the floating diffusion (FD) node by controlling and optimizing the N doping concentration in the PPD and the threshold voltage of the reset transistor, respectively. The techniques shorten the charge transfer time from the PPD diode to the FD node effectively. The proposed process techniques do not need extra masks and do not cause harm to the fill factor. A sub array of 32 × 64 pixels was designed and implemented in the 0.18 μm CIS process with five implantation conditions splitting the N region in the PPD. The simulation and measured results demonstrate that the charge transfer time can be decreased by using the proposed techniques. Comparing the charge transfer time of the pixel with the different implantation conditions of the N region, the charge transfer time of 0.32 μs is achieved and 31% of image lag was reduced by using the proposed process techniques. (semiconductor devices)

  15. Sensing sheet: the response of full-bridge strain sensors to thermal variations for detecting and characterizing cracks

    Science.gov (United States)

    Tung, S.-T.; Glisic, B.

    2016-12-01

    Sensing sheets based on large-area electronics consist of a dense array of unit strain sensors. This new technology has potential for becoming an effective and affordable monitoring tool that can identify, localize and quantify surface damage in structures. This research contributes to their development by investigating the response of full-bridge unit strain sensors to thermal variations. Overall, this investigation quantifies the effects of temperature on thin-film full-bridge strain sensors monitoring uncracked and cracked concrete. Additionally, an empirical formula is developed to estimate crack width given an observed strain change and a measured temperature change. This research led to the understanding of the behavior of full-bridge strain sensors installed on cracked concrete and exposed to temperature variations. It proves the concept of the sensing sheet and its suitability for application in environments with variable temperature.

  16. Spatial Search Techniques for Mobile 3D Queries in Sensor Web Environments

    Directory of Open Access Journals (Sweden)

    James D. Carswell

    2013-03-01

    Full Text Available Developing mobile geo-information systems for sensor web applications involves technologies that can access linked geographical and semantically related Internet information. Additionally, in tomorrow’s Web 4.0 world, it is envisioned that trillions of inexpensive micro-sensors placed throughout the environment will also become available for discovery based on their unique geo-referenced IP address. Exploring these enormous volumes of disparate heterogeneous data on today’s location and orientation aware smartphones requires context-aware smart applications and services that can deal with “information overload”. 3DQ (Three Dimensional Query is our novel mobile spatial interaction (MSI prototype that acts as a next-generation base for human interaction within such geospatial sensor web environments/urban landscapes. It filters information using “Hidden Query Removal” functionality that intelligently refines the search space by calculating the geometry of a three dimensional visibility shape (Vista space at a user’s current location. This 3D shape then becomes the query “window” in a spatial database for retrieving information on only those objects visible within a user’s actual 3D field-of-view. 3DQ reduces information overload and serves to heighten situation awareness on constrained commercial off-the-shelf devices by providing visibility space searching as a mobile web service. The effects of variations in mobile spatial search techniques in terms of query speed vs. accuracy are evaluated and presented in this paper.

  17. Smart Rocks for Bridge Scour Monitoring: Design and Localization Using Electromagnetic Techniques and Embedded Orientation Sensors

    Science.gov (United States)

    Radchenko, Andro

    River bridge scour is an erosion process in which flowing water removes sediment materials (such as sand, rocks) from a bridge foundation, river beds and banks. As a result, the level of the river bed near a bridge pier is lowering such that the bridge foundation stability can be compromised, and the bridge can collapse. The scour is a dynamic process, which can accelerate rapidly during a flood event. Thus, regular monitoring of the scour progress is necessary to be performed at most river bridges. Present techniques are usually expensive, require large man/hour efforts, and often lack the real-time monitoring capabilities. In this dissertation a new method--'Smart Rocks Network for bridge scour monitoring' is introduced. The method is based on distributed wireless sensors embedded in ground underwater nearby the bridge pillars. The sensor nodes are unconstrained in movement, are equipped with years-lasting batteries and intelligent custom designed electronics, which minimizes power consumption during operation and communication. The electronic part consists of a microcontroller, communication interfaces, orientation and environment sensors (such as are accelerometer, magnetometer, temperature and pressure sensors), supporting power supplies and circuitries. Embedded in the soil nearby a bridge pillar the Smart Rocks can move/drift together with the sediments, and act as the free agent probes transmitting the unique signature signals to the base-station monitors. Individual movement of a Smart Rock can be remotely detected processing the orientation sensors reading. This can give an indication of the on-going scour progress, and set a flag for the on-site inspection. The map of the deployed Smart Rocks Network can be obtained utilizing the custom developed in-network communication protocol with signals intensity (RSSI) analysis. Particle Swarm Optimization (PSO) is applied for map reconstruction. Analysis of the map can provide detailed insight into the scour

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

    Energy Technology Data Exchange (ETDEWEB)

    Pilgrim, C. C. [Mechanical Engineering, Imperial College London, London, SW7 2AZ, UK and Sensor Coating Systems, Imperial Incubator, Bessemer Building, Level 1 and 2, Imperial College London, London SW7 2AZ (United Kingdom); Heyes, A. L. [Energy Technology and Innovation Initiative, University of Leeds, Leeds, LS2 9JT (United Kingdom); Feist, J. P. [Sensor Coating Systems, Imperial Incubator, Bessemer Building, Level 1 and 2, Imperial College London, London SW7 2AZ (United Kingdom)

    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 information 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.

  19. Coherent Pound-Drever-Hall technique for high resolution fiber optic strain sensor at very low light power

    Science.gov (United States)

    Wu, Mengxin; Liu, Qingwen; Chen, Jiageng; He, Zuyuan

    2017-04-01

    Pound-Drever-Hall (PDH) technique has been widely adopted for ultrahigh resolution fiber-optic sensors, but its performance degenerates seriously as the light power drops. To solve this problem, we developed a coherent PDH technique for weak optical signal detection, with which the signal-to-noise ratio (SNR) of demodulated PDH signal is dramatically improved. In the demonstrational experiments, a high resolution fiber-optic sensor using the proposed technique is realized, and n"-order strain resolution at a low light power down to -43 dBm is achieved, which is about 15 dB lower compared with classical PDH technique. The proposed coherent PDH technique has great potentials in longer distance and larger scale sensor networks.

  20. Earth Resources: A continuing bibliography with indexes, issue 2. [remote sensors and data acquisition techniques

    Science.gov (United States)

    1975-01-01

    Reports, articles, and other documents announced between April and June 1974 in Scientific and Technical Aerospace Reports (STAR), and International Aerospace Abstracts (IAA) are cited. Documents related to the identification and evaluation by means of sensors in spacecraft and aircraft of vegetation, minerals, and other natural resources, and the techniques and potentialities of surveying and keeping up-to-date inventories of such riches are included along with studies of such natural phenomena as earthquakes, volcanoes, ocean currents, and magnetic fields; and such cultural phenomena as cities, transportation networks, and irrigation systems. The components and use of remote sensing and geophysical instrumentation, their subsystems, observational procedures, signature and analyses and interpretive techniques for gathering data are, described. All reports generated under NASA's Earth Resources Survey Program for the time period covered are included.

  1. Metallographic examination of TD-nickel base alloys. [thermal and chemical etching technique evaluation

    Science.gov (United States)

    Kane, R. D.; Petrovic, J. J.; Ebert, L. J.

    1975-01-01

    Techniques are evaluated for chemical, electrochemical, and thermal etching of thoria dispersed (TD) nickel alloys. An electrochemical etch is described which yielded good results only for large grain sizes of TD-nickel. Two types of thermal etches are assessed for TD-nickel: an oxidation etch and vacuum annealing of a polished specimen to produce an etch. It is shown that the first etch was somewhat dependent on sample orientation with respect to the processing direction, the second technique was not sensitive to specimen orientation or grain size, and neither method appear to alter the innate grain structure when the materials were fully annealed prior to etching. An electrochemical etch is described which was used to observe the microstructures in TD-NiCr, and a thermal-oxidation etch is shown to produce better detail of grain boundaries and to have excellent etching behavior over the entire range of grain sizes of the sample.

  2. Measuring technique of super high temperature thermal properties of reactor core materials

    International Nuclear Information System (INIS)

    Ono, Akira; Baba, Tetsuya; Watanabe, Hideo; Matsumoto, Tsuyoshi

    1998-01-01

    In this study, thermal properties of reactor core materials used for water cooled reactors and FBR were tried to develop a technique to measure their melt states at less than 3,000degC in order to contribute more correct evaluation of the reactor core behavior at severe accident. Then, a thermal property measuring method of high temperature melt by using floating method was investigated and its fundamental design was begun to investigate under a base of optimum judgement on the air flow floating throw-down method. And, in order to measure emissivity of melt specimen surface essential for correct temperature measurement using the throw down method, a spectroscopic emissivity measuring unit using an ellipsometer was prepared and induced. On the thermal properties measurement using the holding method, a specimen container to measure thermal diffusiveness of the high temperature melts by using laser flashing method was tried to prepare. (G.K.)

  3. Self-consistent photothermal techniques: Application for measuring thermal diffusivity in vegetable oils

    Science.gov (United States)

    Balderas-López, J. A.; Mandelis, Andreas

    2003-01-01

    The thermal wave resonator cavity (TWRC) was used to measure the thermal properties of vegetable oils. The thermal diffusivity of six commercial vegetable oils (olive, corn, soybean, canola, peanut, and sunflower) was measured by means of this device. A linear relation between both the amplitude and phase as functions of the cavity length for the TWRC was observed and used for the measurements. Three significant figure precisions were obtained. A clear distinction between extra virgin olive oil and other oils in terms of thermal diffusivity was shown. The high measurement precision of the TWRC highlights the potential of this relatively new technique for assessing the quality of this kind of fluids in terms of their thermophysical properties.

  4. Performance Comparison of Reputation Assessment Techniques Based on Self-Organizing Maps in Wireless Sensor Networks

    Directory of Open Access Journals (Sweden)

    Sabrina Sicari

    2017-01-01

    Full Text Available Many solutions based on machine learning techniques have been proposed in literature aimed at detecting and promptly counteracting various kinds of malicious attack (data violation, clone, sybil, neglect, greed, and DoS attacks, which frequently affect Wireless Sensor Networks (WSNs. Besides recognizing the corrupted or violated information, also the attackers should be identified, in order to activate the proper countermeasures for preserving network’s resources and to mitigate their malicious effects. To this end, techniques adopting Self-Organizing Maps (SOM for intrusion detection in WSN were revealed to represent a valuable and effective solution to the problem. In this paper, the mechanism, namely, Good Network (GoNe, which is based on SOM and is able to assess the reliability of the sensor nodes, is compared with another relevant and similar work existing in literature. Extensive performance simulations, in terms of nodes’ classification, attacks’ identification, data accuracy, energy consumption, and signalling overhead, have been carried out in order to demonstrate the better feasibility and efficiency of the proposed solution in WSN field.

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

    Science.gov (United States)

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

    2016-09-23

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

  6. Optimization of Thermal Aspects of Friction Stir Welding – Initial Studies Using a Space Mapping Technique

    DEFF Research Database (Denmark)

    Larsen, Anders Astrup; Bendsøe, Martin P.; Schmidt, Henrik Nikolaj Blicher

    2007-01-01

    The aim of this paper is to optimize a thermal model of a friction stir welding process. The optimization is performed using a space mapping technique in which an analytical model is used along with the FEM model to be optimized. The results are compared to traditional gradient based optimization...

  7. Antimicrobial properties of uncapped silver nanoparticles synthesized by DC arc thermal plasma technique.

    Science.gov (United States)

    Shinde, Manish; Patil, Rajendra; Karmakar, Soumen; Bhoraskar, Sudha; Rane, Sunit; Gade, Wasudev; Amalnerkar, Dinesh

    2012-02-01

    We, herein, report the antimicrobial properties of uncapped silver nanoparticles for a Gram positive model organism, Bacillus subtilis. Uncapped silver nanoparticles have been prepared using less-explored DC arc thermal plasma technique by considering its large scale generation capability. It is observed that the resultant nanoparticles show size as well as optical property dependent antimicrobial effect.

  8. MEMS Technology Sensors as a More Advantageous Technique for Measuring Foot Plantar Pressure and Balance in Humans

    Directory of Open Access Journals (Sweden)

    Clara Sanz Morère

    2016-01-01

    Full Text Available Locomotor activities are part and parcel of daily human life. During walking or running, feet are subjected to high plantar pressure, leading sometimes to limb problems, pain, or foot ulceration. A current objective in foot plantar pressure measurements is developing sensors that are small in size, lightweight, and energy efficient, while enabling high mobility, particularly for wearable applications. Moreover, improvements in spatial resolution, accuracy, and sensitivity are of interest. Sensors with improved sensing techniques can be applied to a variety of research problems: diagnosing limb problems, footwear design, or injury prevention. This paper reviews commercially available sensors used in foot plantar pressure measurements and proposes the utilization of pressure sensors based on the MEMS (microelectromechanical systems technique. Pressure sensors based on this technique have the capacity to measure pressure with high accuracy and linearity up to high pressure levels. Moreover, being small in size, they are highly suitable for this type of measurement. We present two MEMS sensor models and study their suitability for the intended purpose by performing several experiments. Preliminary results indicate that the sensors are indeed suitable for measuring foot plantar pressure. Importantly, by measuring pressure continuously, they can also be utilized for body balance measurements.

  9. MnNi-based spin valve sensors combining high thermal stability, small footprint and pTesla detectivities

    Science.gov (United States)

    Silva, Marília; Leitao, Diana C.; Cardoso, Susana; Freitas, Paulo

    2018-05-01

    Magnetoresistive sensors with high thermal robustness, low noise and high spatial resolution are the answer to a number of challenging applications. Spin valve sensors including MnNi as antiferromagnet layer provide higher exchange bias field and improved thermal stability. In this work, the influence of the buffer layer type (Ta, NiFeCr) and thickness on key sensor parameters (e.g. offset field, Hf) is investigated. A Ta buffer layer promotes a strong (111) texture which leads to a higher value of MR. In contrast, Hf is lower for NiFeCr buffer. Micrometric sensors display thermal noise levels of 1 nT/Hz1/2 and 571 pT/Hz1/2 for a sensor height (h) of 2 and 4 μm, respectively. The temperature dependence of MR and sensitivity is also addressed and compared with MnIr based spin valves. In this case, MR abruptly decreases after heating at 160°C (without magnetic field), contrary to MnNi-based spin valves, where only a 10% MR decrease (relative to the initial value) is seen at 275°C. Finally, to further decrease the noise levels and improve detectivity, MnNi spin-valves are deposited vertically, and connected in parallel and series (in-plane) to create a device with low resistance and high sensitivity. A field detection at thermal level of 346 pT/Hz1/2 is achieved for a device with a total of 300 SVs (4 vertical, 15 in series, 5 in parallel).

  10. A Survey on Optimal Signal Processing Techniques Applied to Improve the Performance of Mechanical Sensors in Automotive Applications

    Directory of Open Access Journals (Sweden)

    Wilmar Hernandez

    2007-01-01

    Full Text Available In this paper a survey on recent applications of optimal signal processing techniques to improve the performance of mechanical sensors is made. Here, a comparison between classical filters and optimal filters for automotive sensors is made, and the current state of the art of the application of robust and optimal control and signal processing techniques to the design of the intelligent (or smart sensors that today’s cars need is presented through several experimental results that show that the fusion of intelligent sensors and optimal signal processing techniques is the clear way to go. However, the switch between the traditional methods of designing automotive sensors and the new ones cannot be done overnight because there are some open research issues that have to be solved. This paper draws attention to one of the open research issues and tries to arouse researcher’s interest in the fusion of intelligent sensors and optimal signal processing techniques.

  11. Validation and qualification of surface-applied fibre optic strain sensors using application-independent optical techniques

    International Nuclear Information System (INIS)

    Schukar, Vivien G; Kadoke, Daniel; Kusche, Nadine; Münzenberger, Sven; Gründer, Klaus-Peter; Habel, Wolfgang R

    2012-01-01

    Surface-applied fibre optic strain sensors were investigated using a unique validation facility equipped with application-independent optical reference systems. First, different adhesives for the sensor's application were analysed regarding their material properties. Measurements resulting from conventional measurement techniques, such as thermo-mechanical analysis and dynamic mechanical analysis, were compared with measurements resulting from digital image correlation, which has the advantage of being a non-contact technique. Second, fibre optic strain sensors were applied to test specimens with the selected adhesives. Their strain-transfer mechanism was analysed in comparison with conventional strain gauges. Relative movements between the applied sensor and the test specimen were visualized easily using optical reference methods, digital image correlation and electronic speckle pattern interferometry. Conventional strain gauges showed limited opportunities for an objective strain-transfer analysis because they are also affected by application conditions. (paper)

  12. Why General Outlier Detection Techniques Do Not Suffice For Wireless Sensor Networks?

    NARCIS (Netherlands)

    Zhang, Y.; Meratnia, Nirvana; Havinga, Paul J.M.

    2009-01-01

    Raw data collected in wireless sensor networks are often unreliable and inaccurate due to noise, faulty sensors and harsh environmental effects. Sensor data that significantly deviate from normal pattern of sensed data are often called outliers. Outlier detection in wireless sensor networks aims at

  13. Sensor and methodology for dielectric analysis of vegetal oils submitted to thermal stress.

    Science.gov (United States)

    Stevan, Sergio Luiz; Paiter, Leandro; Galvão, José Ricardo; Roque, Daniely Vieira; Chaves, Eduardo Sidinei

    2015-10-16

    Vegetable oils used in frying food represent a social problem as its destination. The residual oil can be recycled and returned to the production line, as biodiesel, as soap, or as putty. The state of the residual oil is determined according to their physicochemical characteristics whose values define its economically viable destination. However, the physicochemical analysis requires high costs, time and general cost of transporting. This study presents the use of a capacitive sensor and a quick and inexpensive method to correlate the physicochemical variables to the dielectric constant of the material undergoing oil samples to thermal cycling. The proposed method allows reducing costs in the characterization of residual oil and the reduction in analysis time. In addition, the method allows an assessment of the quality of the vegetable oil during use. The experimental results show the increasing of the dielectric constant with the temperature, which facilitates measurement and classification of the dielectric constant at considerably higher temperatures. The results also confirm a definitive degradation in used oil and a correlation between the dielectric constant of the sample with the results of the physicochemical analysis (iodine value, acid value, viscosity and refractive index).

  14. Sensor and Methodology for Dielectric Analysis of Vegetal Oils Submitted to Thermal Stress

    Directory of Open Access Journals (Sweden)

    Sergio Luiz Stevan

    2015-10-01

    Full Text Available Vegetable oils used in frying food represent a social problem as its destination. The residual oil can be recycled and returned to the production line, as biodiesel, as soap, or as putty. The state of the residual oil is determined according to their physicochemical characteristics whose values define its economically viable destination. However, the physicochemical analysis requires high costs, time and general cost of transporting. This study presents the use of a capacitive sensor and a quick and inexpensive method to correlate the physicochemical variables to the dielectric constant of the material undergoing oil samples to thermal cycling. The proposed method allows reducing costs in the characterization of residual oil and the reduction in analysis time. In addition, the method allows an assessment of the quality of the vegetable oil during use. The experimental results show the increasing of the dielectric constant with the temperature, which facilitates measurement and classification of the dielectric constant at considerably higher temperatures. The results also confirm a definitive degradation in used oil and a correlation between the dielectric constant of the sample with the results of the physicochemical analysis (iodine value, acid value, viscosity and refractive index.

  15. Second-Generation Thermal Neutron Activation Sensor for Confirmatory Land-Mine Detection

    International Nuclear Information System (INIS)

    Edward Clifford; Harry Ing; John McFee; H. Robert Andrews; Tom Cousins

    2000-01-01

    This paper describes the development of the Improved Land-Mine Detector System (ILDS), a vehicle-mounted nonmetallic land-mine detector. The ILDS consists of a custom teleoperated vehicle carrying an infrared imager, an electromagnetic induction detector, and a ground probing radar-which scan the ground in front of the vehicle. Custom navigation and data fusion software combine information from scanning sensors and navigation systems to detect and automatically track suspect targets until the confirmation detector at the rear of the system is positioned to within 30 cm of the target location. The confirmation detector, using thermal neutron activation (TNA) to detect bulk nitrogen in explosives, then dwells over the target for 10 to 120 s. In U.S. government tests (summer 1998), the ILDS advanced development model (ADM) placed first or second out of five competitors on every test. The construction of the second-generation TNA detector and preliminary testing should be complete by March 2000. Testing on real mines is expected to start in summer 2000

  16. Thermal property characterization of fine fibers by the 3-omega technique

    International Nuclear Information System (INIS)

    Xing, Changhu; Jensen, Colby; Munro, Troy; White, Benjamin; Ban, Heng; Chirtoc, Mihai

    2014-01-01

    The 3 omega method is one of few reliable measurement techniques for thermal characterization of micro to nanoscale suspended wires or fibers and has been applied for measurements of carbon nanotubes and silicon nanowires. However, the models described in the past were either complicated for analysis or simplified from a more complete solution. In addition, the past models cannot be implemented directly when using a more reliable measurement configuration with a Wheatstone bridge. In this work, a simpler, explicit model, is developed to describe the heat transfer process through a suspended wire for measurement of its thermal properties. Generic trends and values of the 3ω harmonic voltage amplitude and phase responses clearly indicate the frequency limits for thermal conductivity and heat capacity determination and ideal conditions for thermal diffusivity estimation. Based on a sensitivity analysis, these limits are confirmed and appropriate frequency ranges for thermal conductivity and diffusivity are recommended. Radiation influence on the measurement results is quantified and correlated to a dimensionless radiation parameter. Two methods are presented to determine sample thermal properties independent of lateral heat losses and validated by numerical experiments using COMSOL. Uncertainty analysis was also derived by Taylor series expansion with calculated parameter sensitivities. - Highlights: • An improved model for suspended wire 3 omega measurement. • Quantification on the radiation induced measurement error. • Numerical simulation validating the improved model. • Sensitivity analysis to find measurement range minimizing uncertainty

  17. Synthesis of {gamma}-aluminium oxynitride spinel using thermal plasma technique

    Energy Technology Data Exchange (ETDEWEB)

    Panda, Pravuram; Singh, S. K.; Sinha, S. P. [School of Applied Science (Physics), KIIT University, Bhubaneswar 751024 (India); Advanced Materials Technology Department, IMMT (CSIR), Bhubaneswar 751013 (India); School of Applied Science (Physics), KIIT University, Bhubaneswar 751024 (India)

    2012-07-23

    The synthesis technique of {gamma}-AlON in NH{sub 3} plasma using extended arc thermal plasma reactor have been reported. Dense cubic AlON spinel was synthesized in liquid state by fusion of mixture of Al{sub 2}O{sub 3} and AlN powder under thermal plasma. The density of the fused AlON was found to be 3.64 g/cc which is 98.11% of theoretical value. The formation of AlON was confirmed from XRD and Raman studies. Well faceted structure of plasma fused AlON was observed in FE-SEM micrograph.

  18. Portable multi-sensor system for gas detection using the temporal window technique; Systeme multicapteurs de detection de gaz, portable, utilisant la technique du fenetrage temporel

    Energy Technology Data Exchange (ETDEWEB)

    Cazaubon, Ch. [Bordeaux-1 Univ., CRED, 33 - Talence (France); Levi, H.; Bordieu, Ch.; Rebiere, D.; Pistre, J. [Bordeaux-1 Univ., Lab. IXL, UMR CNRS 5818, 33 (France)

    1999-07-01

    An autonomous and portable multi-sensor system was constructed. It can drive four gas sensors (surface acoustic waves. SAW. for examples) and four voltage output gas sensors (semiconductor metal oxide sensors, for example). Two micro-controllers. MC68HC11F1 and MC68HC711E9, used as master and slave respectively, are mounted on two cards. The first card contains the signal processing treatment algorithm using a neural network and a shifting temporal window technique: it allows real time gas selection. The second card insure the overall temperature control by an auto-adaptive PID. GB gas SAW responses were applied to the device in order to test his performances. (authors)

  19. Survey on Ranging Sensors and Cooperative Techniques for Relative Positioning of Vehicles

    Directory of Open Access Journals (Sweden)

    Fabian de Ponte Müller

    2017-01-01

    Full Text Available Future driver assistance systems will rely on accurate, reliable and continuous knowledge on the position of other road participants, including pedestrians, bicycles and other vehicles. The usual approach to tackle this requirement is to use on-board ranging sensors inside the vehicle. Radar, laser scanners or vision-based systems are able to detect objects in their line-of-sight. In contrast to these non-cooperative ranging sensors, cooperative approaches follow a strategy in which other road participants actively support the estimation of the relative position. The limitations of on-board ranging sensors regarding their detection range and angle of view and the facility of blockage can be approached by using a cooperative approach based on vehicle-to-vehicle communication. The fusion of both, cooperative and non-cooperative strategies, seems to offer the largest benefits regarding accuracy, availability and robustness. This survey offers the reader a comprehensive review on different techniques for vehicle relative positioning. The reader will learn the important performance indicators when it comes to relative positioning of vehicles, the different technologies that are both commercially available and currently under research, their expected performance and their intrinsic limitations. Moreover, the latest research in the area of vision-based systems for vehicle detection, as well as the latest work on GNSS-based vehicle localization and vehicular communication for relative positioning of vehicles, are reviewed. The survey also includes the research work on the fusion of cooperative and non-cooperative approaches to increase the reliability and the availability.

  20. In Situ Determination of Thermal Profiles during Czochralski Silicon Crystal Growth by an Eddy Current Technique.

    Science.gov (United States)

    Choe, Kwang Su.

    An eddy current testing method was developed to continuously monitor crystal growth process and determine thermal profiles in situ during Czochralski silicon crystal growth. The work was motivated by the need to improve the quality of the crystal by controlling thermal gradients and annealing history over the growth cycle. The experimental concept is to monitor intrinsic electrical conductivities of the growing crystal and deduce temperature values from them. The experiments were performed in a resistance-heated Czochralski puller with a 203 mm (8 inch) diameter crucible containing 6.5 kg melt. The silicon crystals being grown were about 80 mm in diameter and monitored by an encircling sensor operating at three different test frequencies (86, 53 and 19 kHz). A one-dimensional analytical solution was employed to translate the detected signals into electrical conductivities. In terms of experiments, the effects of changes in growth condition, which is defined by crystal and crucible rotation rates, crucible position, pull rate, and hot-zone configuration, were investigated. Under a given steady-state condition, the thermal profile was usually stable over the entire length of crystal growth. The profile shifted significantly, however, when the crucible rotation rate was kept too high. As a direct evidence to the effects of melt flow on heat transfer process, a thermal gradient minimum was observed about the crystal/crucible rotation combination of 20/-10 rpm cw. The thermal gradient reduction was still most pronounced when the pull rate or the radiant heat loss to the environment was decreased: a nearly flat axial thermal gradient was achieved when either the pull rate was halved or the height of the exposed crucible wall was effectively doubled. Under these conditions, the average axial thermal gradient along the surface of the crystal was about 4-5 ^{rm o}C/mm. Regardless of growth condition, the three-frequency data revealed radial thermal gradients much larger

  1. Development of a hybrid earthquake early warning system based on single sensor technique

    International Nuclear Information System (INIS)

    Gravirov, V.V.; Kislov, K.V.

    2012-01-01

    There are two methods to earthquake early warning system: the method based on a network of seismic stations and the single-sensor method. Both have advantages and drawbacks. The current systems rely on high density seismic networks. Attempts at implementing techniques based on the single-station principle encounter difficulties in the identification of earthquake in noise. The noise may be very diverse, from stationary to impulsive. It seems a promising line of research to develop hybrid warning systems with single-sensors being incorporated in the overall early warning network. This will permit using all advantages and will help reduce the radius of the hazardous zone where no earthquake warning can be produced. The main problems are highlighted and the solutions of these are discussed. The system is implemented to include three detection processes in parallel. The first is based on the study of the co-occurrence matrix of the signal wavelet transform. The second consists in using the method of a change point in a random process and signal detection in a moving time window. The third uses artificial neural networks. Further, applying a decision rule out the final earthquake detection is carried out and estimate its reliability. (author)

  2. Application of the thermal plasma technique in the treatment of stone surfaces

    International Nuclear Information System (INIS)

    Gonzalez A, Z.I.

    2000-01-01

    The stone materials which form part of the cultural heritage of Mexico, are degraded under the united action of water, atmospheric gases, air pollution, temperature changes and the microorganisms action; provoking on the stone: fissures, crevices, scalings, fragmentations, pulverizations, etc. Therefore, the purpose of this work is to study the possibilities to apply a protective coating on the stone surfaces, previously clean and consolidated, through the thermal plasma technique. The purpose is to analyse the physical and chemical properties of three types of stone materials: quarry, tezontle and chiluca, usually used in constructions of cultural interest such as: historical monuments, churches, sculptures, etc., before and after to be submitted to the action of thermal plasma in order to examine the feasibility in the use of this coating technique in this type of applications. The application of conventional techniques to determine: porosity, density, absorption, low pressure water absorption and crystallization by total immersion of nuclear techniques such as: neutron activation analysis, x-ray diffraction and scanning electron microscopy as well as of instrumental techniques: optical microscopy, mechanical assays of compression, flexure and surface area calculations, allowed to know the chemical and physical properties of the stone material before and after to be treated through the thermal plasma technique, projecting quartz on the stones surface at different distances and current intensity and showing the effect caused by the modifications or surface alterations present by cause of the application of that coating. the obtained results provide a general panorama of the application of this technique as an alternative to the maintenance of the architectural inheritance built in stone. (Author)

  3. A Wireless Sensor Network with Soft Computing Localization Techniques for Track Cycling Applications.

    Science.gov (United States)

    Gharghan, Sadik Kamel; Nordin, Rosdiadee; Ismail, Mahamod

    2016-08-06

    In this paper, we propose two soft computing localization techniques for wireless sensor networks (WSNs). The two techniques, Neural Fuzzy Inference System (ANFIS) and Artificial Neural Network (ANN), focus on a range-based localization method which relies on the measurement of the received signal strength indicator (RSSI) from the three ZigBee anchor nodes distributed throughout the track cycling field. The soft computing techniques aim to estimate the distance between bicycles moving on the cycle track for outdoor and indoor velodromes. In the first approach the ANFIS was considered, whereas in the second approach the ANN was hybridized individually with three optimization algorithms, namely Particle Swarm Optimization (PSO), Gravitational Search Algorithm (GSA), and Backtracking Search Algorithm (BSA). The results revealed that the hybrid GSA-ANN outperforms the other methods adopted in this paper in terms of accuracy localization and distance estimation accuracy. The hybrid GSA-ANN achieves a mean absolute distance estimation error of 0.02 m and 0.2 m for outdoor and indoor velodromes, respectively.

  4. A Comparative Study of Anomaly Detection Techniques for Smart City Wireless Sensor Networks.

    Science.gov (United States)

    Garcia-Font, Victor; Garrigues, Carles; Rifà-Pous, Helena

    2016-06-13

    In many countries around the world, smart cities are becoming a reality. These cities contribute to improving citizens' quality of life by providing services that are normally based on data extracted from wireless sensor networks (WSN) and other elements of the Internet of Things. Additionally, public administration uses these smart city data to increase its efficiency, to reduce costs and to provide additional services. However, the information received at smart city data centers is not always accurate, because WSNs are sometimes prone to error and are exposed to physical and computer attacks. In this article, we use real data from the smart city of Barcelona to simulate WSNs and implement typical attacks. Then, we compare frequently used anomaly detection techniques to disclose these attacks. We evaluate the algorithms under different requirements on the available network status information. As a result of this study, we conclude that one-class Support Vector Machines is the most appropriate technique. We achieve a true positive rate at least 56% higher than the rates achieved with the other compared techniques in a scenario with a maximum false positive rate of 5% and a 26% higher in a scenario with a false positive rate of 15%.

  5. A Comparative Study of Anomaly Detection Techniques for Smart City Wireless Sensor Networks

    Directory of Open Access Journals (Sweden)

    Victor Garcia-Font

    2016-06-01

    Full Text Available In many countries around the world, smart cities are becoming a reality. These cities contribute to improving citizens’ quality of life by providing services that are normally based on data extracted from wireless sensor networks (WSN and other elements of the Internet of Things. Additionally, public administration uses these smart city data to increase its efficiency, to reduce costs and to provide additional services. However, the information received at smart city data centers is not always accurate, because WSNs are sometimes prone to error and are exposed to physical and computer attacks. In this article, we use real data from the smart city of Barcelona to simulate WSNs and implement typical attacks. Then, we compare frequently used anomaly detection techniques to disclose these attacks. We evaluate the algorithms under different requirements on the available network status information. As a result of this study, we conclude that one-class Support Vector Machines is the most appropriate technique. We achieve a true positive rate at least 56% higher than the rates achieved with the other compared techniques in a scenario with a maximum false positive rate of 5% and a 26% higher in a scenario with a false positive rate of 15%.

  6. Supplier Selection in the Thermal Tourism Enterprises with Using Multi Criteria Decision Making Techniques

    Directory of Open Access Journals (Sweden)

    Hatice Gündüz

    2015-06-01

    Full Text Available Turkey has many natural health resources and the interest in Thermal Tourism has increased. Thermal Tourism Enterprises serve their experienced medical staff, treatment methods and the curative springs for the purpose of care services. On the other hand, these enterprises are also the place to have both a rest and a good time. In this study, the supplier selection application is performed in the Thermal Tourism Enterprise that offers a combination of services as health, recreation and entertainment. The criteria as product quality and performance, product information, product arrival time, price, quality practices, flexibility and the collaboration level have been considered. By using multi-criteria decision making techniques as Analytic Hierarchy Process (AHP and TOPSIS then the suggestions on the selecting the best supplier are offered.

  7. Research technique and experimental device for thermal conductivity measurements of refractory compounds

    International Nuclear Information System (INIS)

    Vishnevetskaya, I.A.; Petrov, V.A.

    1977-01-01

    Proposed is a new axial technique for determining thermal conductivity coefficient of solids at temperatures above 1000 deg C with the use of internal heating of specimens by passing electric current and with experimental determining the thermal flows on the lateral side of the working section of the specimen. This method is usable for investigating the thermal conductivity of materials whose surface radiation characteristics are unknown or unstable and for carrying out experiments not only in vacuum, but also in various atmospheres. The overall fiducial error of the results of the method is evaluated at 4-5 % within the range of temperatures between 1200 and 2300 K. A description of the experimental installation is given

  8. Image accuracy and representational enhancement through low-level, multi-sensor integration techniques

    International Nuclear Information System (INIS)

    Baker, J.E.

    1993-05-01

    Multi-Sensor Integration (MSI) is the combining of data and information from more than one source in order to generate a more reliable and consistent representation of the environment. The need for MSI derives largely from basic ambiguities inherent in our current sensor imaging technologies. These ambiguities exist as long as the mapping from reality to image is not 1-to-1. That is, if different 44 realities'' lead to identical images, a single image cannot reveal the particular reality which was the truth. MSI techniques can be divided into three categories based on the relative information content of the original images with that of the desired representation: (1) ''detail enhancement,'' wherein the relative information content of the original images is less rich than the desired representation; (2) ''data enhancement,'' wherein the MSI techniques axe concerned with improving the accuracy of the data rather than either increasing or decreasing the level of detail; and (3) ''conceptual enhancement,'' wherein the image contains more detail than is desired, making it difficult to easily recognize objects of interest. In conceptual enhancement one must group pixels corresponding to the same conceptual object and thereby reduce the level of extraneous detail. This research focuses on data and conceptual enhancement algorithms. To be useful in many real-world applications, e.g., autonomous or teleoperated robotics, real-time feedback is critical. But, many MSI/image processing algorithms require significant processing time. This is especially true of feature extraction, object isolation, and object recognition algorithms due to their typical reliance on global or large neighborhood information. This research attempts to exploit the speed currently available in state-of-the-art digitizers and highly parallel processing systems by developing MSI algorithms based on pixel rather than global-level features

  9. A novel measurement method for the thermal properties of liquids by utilizing a bridge-based micromachined sensor

    International Nuclear Information System (INIS)

    Beigelbeck, Roman; Nachtnebel, Herbert; Kohl, Franz; Jakoby, Bernhard

    2011-01-01

    In recent decades, the demands for online monitoring of liquids in various applications have increased significantly. In this context, the sensing of the thermal transport parameters of liquids (i.e. thermal conductivity and diffusivity) may be an interesting alternative to well-established monitoring parameters like permittivity, mass density or shear viscosity. We developed a micromachined thermal property sensor, applicable to non-flowing liquids, featuring three in parallel microbridges, which carry either a heater or one of in total two thermistors. Its active sensing region was designed to achieve almost negligible spurious thermal shunts between heater and thermistors. This enables the adoption of a simple two-dimensional model to describe the heat transfer from the heater to the thermistors, which is mainly governed by the thermal properties of the sample liquid. Founded on this theoretical model, a novel measurement method for the thermal parameters was devised that relies solely on the frequency response of the measured peak temperature and allows simultaneous extraction of the thermal conductivity and diffusivity of liquids. In this contribution, we describe the device prototype, the model, the deduced measurement method and the experimental verification by means of test measurements carried out on five sample liquids

  10. An extended laser flash technique for thermal diffusivity measurement of high-temperature materials

    Science.gov (United States)

    Shen, F.; Khodadadi, J. M.

    1993-01-01

    Knowledge of thermal diffusivity data for high-temperature materials (solids and liquids) is very important in analyzing a number of processes, among them solidification, crystal growth, and welding. However, reliable thermal diffusivity versus temperature data, particularly those for high-temperature liquids, are still far from complete. The main measurement difficulties are due to the presence of convection and the requirement for a container. Fortunately, the availability of levitation techniques has made it possible to solve the containment problem. Based on the feasibility of the levitation technology, a new laser flash technique which is applicable to both levitated liquid and solid samples is being developed. At this point, the analysis for solid samples is near completion and highlights of the technique are presented here. The levitated solid sample which is assumed to be a sphere is subjected to a very short burst of high power radiant energy. The temperature of the irradiated surface area is elevated and a transient heat transfer process takes place within the sample. This containerless process is a two-dimensional unsteady heat conduction problem. Due to the nonlinearity of the radiative plus convective boundary condition, an analytic solution cannot be obtained. Two options are available at this point. Firstly, the radiation boundary condition can be linearized, which then accommodates a closed-form analytic solution. Comparison of the analytic curves for the temperature rise at different points to the experimentally-measured values will then provide the thermal diffusivity values. Secondly, one may set up an inverse conduction problem whereby experimentally obtained surface temperature history is used as the boundary conditions. The thermal diffusivity can then be elevated by minimizing the difference between the real heat flux boundary condition (radiation plus convection) and the measurements. Status of an experimental study directed at measuring the

  11. Thermal conductivity of organic semi-conducting materials using 3omega and photothermal radiometry techniques

    Directory of Open Access Journals (Sweden)

    Reisdorffer Frederic

    2014-01-01

    Full Text Available Organic semiconductors for opto-electronic devices show several defects which can be enhanced while increasing the operating temperature. Their thermal management and especially the reduction of their temperature are of great interest. For the heat transfer study, one has to measure the thermal conductivity of thin film organic materials. However the major difficulty for this measurement is the very low thickness of the films which needs the use of very specific techniques. In our work, the 3-omega and photothermal radiometric methods were used to measure the thermal conductivity of thin film organic semiconducting material (Alq3. The measurements were performed as function of the thin film thickness from 45 to 785 nm and also of its temperature from 80 to 350 K. With the 3 omega method, a thermal conductivity value of 0.066 W.m−1K−1 was obtained for Alq3 thin film of 200 nm at room temperature, in close agreement with the photothermal value. Both techniques appear to be complementary: the 3 omega method is easier to implement for large temperature range and small thicknesses down to a few tens of nanometers whereas the photothermal method is more suitable for thicknesses over 200nm since it provides additional information such as the thin film volumetric heat capacity.

  12. Simultaneous Absorptance and Thermal-Diffusivity Determination of Optical Components with Laser Calorimetry Technique

    Science.gov (United States)

    Wang, Yanru; Li, Bincheng

    2012-11-01

    The laser calorimetry (LCA) technique is used to determine simultaneously the absorptances and thermal diffusivities of optical components. An accurate temperature model, in which both the finite thermal conductivity and the finite sample size are taken into account, is employed to fit the experimental temperature data measured with an LCA apparatus for a precise determination of the absorptance and thermal diffusivity via a multiparameter fitting procedure. The uniqueness issue of the multiparameter fitting is discussed in detail. Experimentally, highly reflective (HR) samples prepared with electron-beam evaporation on different substrates (BK7, fused silica, and Ge) are measured with LCA. For the HR-coated sample on a fused silica substrate, the absorptance is determined to be 15.4 ppm, which is close to the value of 17.6 ppm, determined with a simplified temperature model recommended in the international standard ISO11551. The thermal diffusivity is simultaneously determined via multiparameter fitting to be approximately 6.63 × 10-7 m2 · s-1 with a corresponding square variance of 4.8 × 10-4. The fitted thermal diffusivity is in reasonably good agreement with the literature value (7.5 × 10-7 m2 · s -1). Good agreement is also obtained for samples with BK7 and Ge substrates.

  13. Experimental study on thermal hazard of tributyl phosphate-nitric acid mixtures using micro calorimeter technique

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Qi; Jiang, Lin; Gong, Liang; Sun, Jin-Hua, E-mail: sunjh@ustc.edu.cn

    2016-08-15

    Highlights: • Heat flows after mixing TBP with nitric acid are of different orders of magnitude. • Thermodynamics and kinetics of tributyl phosphate-nitric acid mixtures are derived. • Tributyl phosphate directly reacts with nitric acid and form organic red oil. • Thermal runaway could occur at 79 °C with a high nitric acid concentration. - Abstract: During PUREX spent nuclear fuel reprocessing, mixture of tributyl phosphate (TBP) and hydrocarbon solvent are employed as organic solvent to extract uranium in consideration of radiation contaminated safety and resource recycling, meanwhile nitric acid is utilized to dissolve the spent fuel into small pieces. However, once TBP contacts with nitric acid or nitrates above 130 °C, a heavy “red oil” layer would occur accompanied by thermal runaway reactions, even caused several nuclear safety accident. Considering nitric acid volatility and weak exothermic detection, C80 micro calorimeter technique was used in this study to investigate thermal decomposition of TBP mixed with nitric acid. Results show that the concentration of nitric acid greatly influences thermal hazard of the system by direct reactions. Even with a low heating rate, if the concentration of nitric acid increases due to evaporation of water or improper operations, thermal runaway in the closed system could start at a low temperature.

  14. Transport and calorimetric properties of AISI 321 by pulse thermal diffusivity and calorimetric techniques

    International Nuclear Information System (INIS)

    Perovic, N.L.; Maglic, K.D.; Stanimirovic, A.M.; Vukovic, G.S.

    1995-01-01

    The study of the thermophysical properties of AISI 321 stainless steel was the last part of work within the IAEA-coordinated Research Programme for the Establishment of a Database of Thermophysical Properties of LW and HW Reactor Materials (IAEA CRP) effected at the Institute of Nuclear Sciences Vinca (NIV). The AISI 321 stainless steel belongs to the group of construction materials whose thermophysical and calorimetric properties have significance for the IAEA CRP. Because there have been few investigations of the thermal properties of this material, the CRP foresaw the need for new measurements, which are reported in this paper. Experimental research performed at NIV consisted of the investigation of thermal diffusivity, electric resistivity, and specific heat capacity of this austenitic stainless steel. The thermal diffusivity was measured by the laser pulse technique, and the elastic resistivity and specific heat capacity were determined by use of millisecond-resolution pulse calorimetry. All measurements were performed from ambient temperature to above 1000 o C, within which temperature range the material maintains its structure and stable thermophysical properties. Values for the thermal conductivity were computed from data on the thermal diffusivity, specific heat capacity, and the room-temperature density. (author)

  15. Development of a Nondestructive Evaluation Technique for Degraded Thermal Barrier Coatings Using Microwave

    Science.gov (United States)

    Sayar, M.; Ogawa, K.; Shoji, T.

    2008-02-01

    Thermal barrier coatings have been widely used in gas turbine engines in order to protect substrate metal alloy against high temperature and to enhance turbine efficiency. Currently, there are no reliable nondestructive techniques available to monitor TBC integrity over lifetime of the coating. Hence, to detect top coating (TC) and TGO thicknesses, a microwave nondestructive technique that utilizes a rectangular waveguide was developed. The phase of the reflection coefficient at the interface of TC and waveguide varies for different TGO and TC thicknesses. Therefore, measuring the phase of the reflection coefficient enables us to accurately calculate these thicknesses. Finally, a theoretical analysis was used to evaluate the reliability of the experimental results.

  16. Estimation of fracture parameters in foam core materials using thermal techniques

    DEFF Research Database (Denmark)

    Dulieu-Barton, J. M.; Berggreen, Christian; Boyenval Langlois, C.

    2010-01-01

    is described. A mode I simulated crack in the form of a machined notch is used to establish the feasibility of the TSA approach to derive stress intensity factors for the foam material. The overall goal is to demonstrate that thermal techniques have the ability to provide deeper insight into the behaviour......The paper presents some initial work on establishing the stress state at a crack tip in PVC foam material using a non-contact infra-red technique known as thermoelastic stress analysis (TSA). A parametric study of the factors that may affect the thermoelastic response of the foam material...

  17. Separation Techniques for Uranium and Plutonium at Trace Levels for the Thermal Ionization Mass Spectrometric Determination

    International Nuclear Information System (INIS)

    Suh, M. Y.; Han, S. H.; Kim, J. G.; Park, Y. J.; Kim, W. H.

    2005-12-01

    This report describes the state of the art and the progress of the chemical separation and purification techniques required for the thermal ionization mass spectrometric determination of uranium and plutonium in environmental samples at trace or ultratrace levels. Various techniques, such as precipitation, solvent extraction, extraction chromatography, and ion exchange chromatography, for separation of uranium and plutonium were evaluated. Sample preparation methods and dissolution techniques for environmental samples were also discussed. Especially, both extraction chromatographic and anion exchange chromatographic procedures for uranium and plutonium in environmental samples, such as soil, sediment, plant, seawater, urine, and bone ash were reviewed in detail in order to propose some suitable methods for the separation and purification of uranium and plutonium from the safeguards environmental or swipe samples. A survey of the IAEA strengthened safeguards system, the clean room facility of IAEA's NWAL(Network of Analytical Laboratories), and the analytical techniques for safeguards environmental samples was also discussed here

  18. Quality control for total evaporation technique by surface/thermal ionization mass spectrometer

    International Nuclear Information System (INIS)

    Kato, Seikou; Inoue, Sinichi; Yamaguchi, Katsuyuki; Tsutaki, Yasuhiro

    2007-01-01

    For the measurement of uranium and plutonium isotopic composition, the surface/thermal ionization mass spectrometry is widely used at the both nuclear facilities and safeguards verification laboratories. The progress of instrument specification makes higher sensitivity. The total evaporation technique is one of the latest measurement techniques by using this progress, in which all of uranium or plutonium on the filament would be evaporated by increasing the filament current. The accuracy and precision of this technique is normally checked by using the certified isotope reference materials measurement. But the fluctuation of ion beam is very different by each filament, depending on the chemical form of evaporation. So, it should be considered how to check the measurement quality of unknown samples which has no certified values. This presentation is focused on the monitoring of ion yields and pattern of isotope ratio fluctuation to attain the traceability between reference material and unknown sample as quality control approach of total evaporation technique. (author)

  19. Analysis of rocks involving the x-ray diffraction, infrared and thermal gravimetric techniques

    International Nuclear Information System (INIS)

    Ikram, M.; Rauf, M.A.; Munir, N.

    1998-01-01

    Chemical analysis of rocks and minerals are usually obtained by a number of analytical techniques. The purpose of present work is to investigate the chemical composition of the rock samples and also to find that how far the results obtained by different instrumental methods are closely related. Chemical tests wee performed before using the instrumental techniques in order to determined the nature of these rocks. The chemical analysis indicated mainly the presence of carbonate and hence the carbonate nature of these rocks. The x-ray diffraction, infrared spectroscopy and thermal gravimetric analysis techniques were used for the determination of chemical composition of these samples. The results obtained by using these techniques have shown a great deal of similarities. (author)

  20. Separation Techniques for Uranium and Plutonium at Trace Levels for the Thermal Ionization Mass Spectrometric Determination

    Energy Technology Data Exchange (ETDEWEB)

    Suh, M. Y.; Han, S. H.; Kim, J. G.; Park, Y. J.; Kim, W. H

    2005-12-15

    This report describes the state of the art and the progress of the chemical separation and purification techniques required for the thermal ionization mass spectrometric determination of uranium and plutonium in environmental samples at trace or ultratrace levels. Various techniques, such as precipitation, solvent extraction, extraction chromatography, and ion exchange chromatography, for separation of uranium and plutonium were evaluated. Sample preparation methods and dissolution techniques for environmental samples were also discussed. Especially, both extraction chromatographic and anion exchange chromatographic procedures for uranium and plutonium in environmental samples, such as soil, sediment, plant, seawater, urine, and bone ash were reviewed in detail in order to propose some suitable methods for the separation and purification of uranium and plutonium from the safeguards environmental or swipe samples. A survey of the IAEA strengthened safeguards system, the clean room facility of IAEA's NWAL(Network of Analytical Laboratories), and the analytical techniques for safeguards environmental samples was also discussed here.

  1. Improving of the photovoltaic / thermal system performance using water cooling technique

    International Nuclear Information System (INIS)

    Hussien, Hashim A; Numan, Ali H; Abdulmunem, Abdulmunem R

    2015-01-01

    This work is devoted to improving the electrical efficiency by reducing the rate of thermal energy of a photovoltaic/thermal system (PV/T).This is achieved by design cooling technique which consists of a heat exchanger and water circulating pipes placed at PV module rear surface to solve the problem of the high heat stored inside the PV cells during the operation. An experimental rig is designed to investigate and evaluate PV module performance with the proposed cooling technique. This cooling technique is the first work in Iraq to dissipate the heat from PV module. The experimental results indicated that due to the heat loss by convection between water and the PV panel's upper surface, an increase of output power is achieved. It was found that without active cooling, the temperature of the PV module was high and solar cells could only achieve a conversion efficiency of about 8%. However, when the PV module was operated under active water cooling condition, the temperature was dropped from 76.8°C without cooling to 70.1°C with active cooling. This temperature dropping led to increase in the electrical efficiency of solar panel to 9.8% at optimum mass flow rate (0.2L/s) and thermal efficiency to (12.3%). (paper)

  2. A Noncontact Measurement Technique for the Density and Thermal Expansion Coefficient of Solid and Liquid Materials

    Science.gov (United States)

    Chung, Sang K.; Thiessen, David B.; Rhim, Won-Kyu

    1996-01-01

    A noncontact measurement technique for the density and the thermal expansion refractory materials in their molten as well as solid phases is presented. This technique is based on the video image processing of a levitated sample. Experiments were performed using the high-temperature electrostatic levitator (HTESL) at the Jet Propulsion Laboratory in which 2-3 mm diameter samples can be levitated, melted, and radiatively cooled in a vacuum. Due to the axisymmetric nature of the molten samples when levitated in the HTESL, a rather simple digital image analysis can be employed to accurately measure the volumetric change as a function of temperature. Density and the thermal expansion coefficient measurements were made on a pure nickel sample to test the accuracy of the technique in the temperature range of 1045-1565 C. The result for the liquid phase density can be expressed by p = 8.848 + (6.730 x 10(exp -4)) x T (degC) g/cu cm within 0.8% accuracy, and the corresponding thermal expansion coefficient can be expressed by Beta=(9.419 x 10(exp -5)) - (7.165 x 10(exp -9) x T (degC)/K within 0.2% accuracy.

  3. Rapid synthesis of tin oxide nanostructures by microwave-assisted thermal oxidation for sensor applications

    Science.gov (United States)

    Phadungdhitidhada, S.; Ruankham, P.; Gardchareon, A.; Wongratanaphisan, D.; Choopun, S.

    2017-09-01

    In the present work nanostructures of tin oxides were synthesized by a microwave-assisted thermal oxidation. Tin precursor powder was loaded into a cylindrical quartz tube and further radiated in a microwave oven. The as-synthesized products were characterized by scanning electron microscope, transmission electron microscope, and x-ray diffractometer. The results showed that two different morphologies of SnO2 microwires (MWs) and nanoparticles (NPs) were obtained in one minute of microwave radiation under atmospheric ambient. A few tens of the SnO2 MWs with the length of 10-50 µm were found. Some parts of the MWs were decorated with the SnO2 NPs. However, most of the products were SnO2 NPs with the diameter ranging from 30-200 nm. Preparation under loosely closed system lead to mixed phase SnO-SnO2 NPs with diameter of 30-200 nm. The single-phase of SnO2 could be obtained by mixing the Sn precursor powders with CuO2. The products were mostly found to be SnO2 nanowires (NWs) and MWs. The diameter of SnO2 NWs was less than 50 nm. The SnO2 NPs, MWs, and NWs were in the cassiterite rutile structure phase. The SnO NPs was in the tetragonal structure phase. The growth direction of the SnO2 NWs was observed in (1 1 0) and (2 2 1) direction. The ethanol sensor performance of these tin oxide nanostructures showed that the SnO-SnO2 NPs exhibited extremely high sensitivity. Invited talk at 5th Thailand International Nanotechnology Conference (Nano Thailand-2016), 27-29 November 2016, Nakhon Ratchasima, Thailand.

  4. A parylene-filled-trench technique for thermal isolation in silicon-based microdevices

    International Nuclear Information System (INIS)

    Lei Yinhua; Wang Wei; Li Ting; Jin Yufeng; Zhang Haixia; Li Zhihong; Yu Huaiqiang; Luo Yingcun

    2009-01-01

    Microdevices prepared in a silicon substrate have been widely used in versatile fields due to the matured silicon-based microfabrication technique and the excellent physical properties of silicon material. However, the high thermal conductivity of silicon restricts its application in most thermal microdevices, especially devices comprising different temperature zones. In this work, a parylene-filled-trench technique was optimized to realize high-quality thermal isolation in silicon-based microdevices. Parylene C, a heat transfer barricading material, was deposited on parallel high-aspect-ratio trenches, which surrounded the isolated target zones. After removing the remnant silicon beneath the trenches by deep reactive ion etching from the back side, a high-quality heat transfer barrier was obtained. By using narrow trenches, only 5 µm thick parylene was required for a complete filling, which facilitated multi-layer interconnection thereafter. The parylene filling performance inside the high-aspect-ratio trench was optimized by two approaches: multiple etch–deposition cycling and trench profile controlling. A 4 × 6 array, in which each unit was kept at a constant temperature and was well thermally isolated individually, was achieved on a silicon substrate by using the present parylene-filled-trench technique. The preliminary experimental results indicated that the present parylene-filled-trench structure exhibited excellent thermal isolation performance, with a very low power requirement of 0.134 mW (K mm 2 ) −1 for heating the isolated silicon unit and a high thermal isolation efficiency of 72.5% between two adjacent units. Accompanied with high-quality isolation performance, the microdevices embedded the present parylene-filled-trench structure to retain a strong mechanical connection larger than 400 kPa between two isolated zones, which is very important for a high-reliability-required micro-electro-mechanical-system (MEMS) device. Considering its room

  5. A Smart Sensor Data Transmission Technique for Logistics and Intelligent Transportation Systems

    OpenAIRE

    Kyunghee Sun; Intae Ryoo

    2018-01-01

    When it comes to Internet of Things systems that include both a logistics system and an intelligent transportation system, a smart sensor is one of the key elements to collect useful information whenever and wherever necessary. This study proposes the Smart Sensor Node Group Management Medium Access Control Scheme designed to group smart sensor devices and collect data from them efficiently. The proposed scheme performs grouping of portable sensor devices connected to a system depending on th...

  6. Evaluation of water-use efficiency in foxtail millet (Setaria italica) using visible-near infrared and thermal spectral sensing techniques.

    Science.gov (United States)

    Wang, Meng; Ellsworth, Patrick Z; Zhou, Jianfeng; Cousins, Asaph B; Sankaran, Sindhuja

    2016-05-15

    Water limitations decrease stomatal conductance (g(s)) and, in turn, photosynthetic rate (A(net)), resulting in decreased crop productivity. The current techniques for evaluating these physiological responses are limited to leaf-level measures acquired by measuring leaf-level gas exchange. In this regard, proximal sensing techniques can be a useful tool in studying plant biology as they can be used to acquire plant-level measures in a high-throughput manner. However, to confidently utilize the proximal sensing technique for high-throughput physiological monitoring, it is important to assess the relationship between plant physiological parameters and the sensor data. Therefore, in this study, the application of rapid sensing techniques based on thermal imaging and visual-near infrared spectroscopy for assessing water-use efficiency (WUE) in foxtail millet (Setaria italica (L.) P. Beauv) was evaluated. The visible-near infrared spectral reflectance (350-2500 nm) and thermal (7.5-14 µm) data were collected at regular intervals from well-watered and drought-stressed plants in combination with other leaf physiological parameters (transpiration rate-E, A(net), g(s), leaf carbon isotopic signature-δ(13)C(leaf), WUE). Partial least squares regression (PLSR) analysis was used to predict leaf physiological measures based on the spectral data. The PLSR modeling on the hyperspectral data yielded accurate and precise estimates of leaf E, gs, δ(13)C(leaf), and WUE with coefficient of determination in a range of 0.85-0.91. Additionally, significant differences in average leaf temperatures (~1°C) measured with a thermal camera were observed between well-watered plants and drought-stressed plants. In summary, the visible-near infrared reflectance data, and thermal images can be used as a potential rapid technique for evaluating plant physiological responses such as WUE. Copyright © 2016 Elsevier B.V. All rights reserved.

  7. Planar Zeolite Film-Based Potentiometric Gas Sensors Manufactured by a Combined Thick-Film and Electroplating Technique

    Science.gov (United States)

    Marr, Isabella; Reiß, Sebastian; Hagen, Gunter; Moos, Ralf

    2011-01-01

    Zeolites are promising materials in the field of gas sensors. In this technology-oriented paper, a planar setup for potentiometric hydrocarbon and hydrogen gas sensors using zeolites as ionic sodium conductors is presented, in which the Pt-loaded Na-ZSM-5 zeolite is applied using a thick-film technique between two interdigitated gold electrodes and one of them is selectively covered for the first time by an electroplated chromium oxide film. The influence of the sensor temperature, the type of hydrocarbons, the zeolite film thickness, and the chromium oxide film thickness is investigated. The influence of the zeolite on the sensor response is briefly discussed in the light of studies dealing with zeolites as selectivity-enhancing cover layers. PMID:22164042

  8. Planar Zeolite Film-Based Potentiometric Gas Sensors Manufactured by a Combined Thick-Film and Electroplating Technique

    Directory of Open Access Journals (Sweden)

    Gunter Hagen

    2011-08-01

    Full Text Available Zeolites are promising materials in the field of gas sensors. In this technology-oriented paper, a planar setup for potentiometric hydrocarbon and hydrogen gas sensors using zeolites as ionic sodium conductors is presented, in which the Pt-loaded Na-ZSM-5 zeolite is applied using a thick-film technique between two interdigitated gold electrodes and one of them is selectively covered for the first time by an electroplated chromium oxide film. The influence of the sensor temperature, the type of hydrocarbons, the zeolite film thickness, and the chromium oxide film thickness is investigated. The influence of the zeolite on the sensor response is briefly discussed in the light of studies dealing with zeolites as selectivity-enhancing cover layers.

  9. A signal combining technique based on channel shortening for cooperative sensor networks

    KAUST Repository

    Hussain, Syed Imtiaz; Alouini, Mohamed-Slim; Hasna, Mazen Omar

    2010-01-01

    The cooperative relaying process needs proper coordination among the communicating and the relaying nodes. This coordination and the required capabilities may not be available in some wireless systems, e.g. wireless sensor networks where the nodes are equipped with very basic communication hardware. In this paper, we consider a scenario where the source node transmits its signal to the destination through multiple relays in an uncoordinated fashion. The destination can capture the multiple copies of the transmitted signal through a Rake receiver. We analyze a situation where the number of Rake fingers N is less than that of the relaying nodes L. In this case, the receiver can combine N strongest signals out of L. The remaining signals will be lost and act as interference to the desired signal components. To tackle this problem, we develop a novel signal combining technique based on channel shortening. This technique proposes a processing block before the Rake reception which compresses the energy of L signal components over N branches while keeping the noise level at its minimum. The proposed scheme saves the system resources and makes the received signal compatible to the available hardware. Simulation results show that it outperforms the selection combining scheme. ©2010 IEEE.

  10. Depth estimation of features in video frames with improved feature matching technique using Kinect sensor

    Science.gov (United States)

    Sharma, Kajal; Moon, Inkyu; Kim, Sung Gaun

    2012-10-01

    Estimating depth has long been a major issue in the field of computer vision and robotics. The Kinect sensor's active sensing strategy provides high-frame-rate depth maps and can recognize user gestures and human pose. This paper presents a technique to estimate the depth of features extracted from video frames, along with an improved feature-matching method. In this paper, we used the Kinect camera developed by Microsoft, which captured color and depth images for further processing. Feature detection and selection is an important task for robot navigation. Many feature-matching techniques have been proposed earlier, and this paper proposes an improved feature matching between successive video frames with the use of neural network methodology in order to reduce the computation time of feature matching. The features extracted are invariant to image scale and rotation, and different experiments were conducted to evaluate the performance of feature matching between successive video frames. The extracted features are assigned distance based on the Kinect technology that can be used by the robot in order to determine the path of navigation, along with obstacle detection applications.

  11. A signal combining technique based on channel shortening for cooperative sensor networks

    KAUST Repository

    Hussain, Syed Imtiaz

    2010-06-01

    The cooperative relaying process needs proper coordination among the communicating and the relaying nodes. This coordination and the required capabilities may not be available in some wireless systems, e.g. wireless sensor networks where the nodes are equipped with very basic communication hardware. In this paper, we consider a scenario where the source node transmits its signal to the destination through multiple relays in an uncoordinated fashion. The destination can capture the multiple copies of the transmitted signal through a Rake receiver. We analyze a situation where the number of Rake fingers N is less than that of the relaying nodes L. In this case, the receiver can combine N strongest signals out of L. The remaining signals will be lost and act as interference to the desired signal components. To tackle this problem, we develop a novel signal combining technique based on channel shortening. This technique proposes a processing block before the Rake reception which compresses the energy of L signal components over N branches while keeping the noise level at its minimum. The proposed scheme saves the system resources and makes the received signal compatible to the available hardware. Simulation results show that it outperforms the selection combining scheme. ©2010 IEEE.

  12. [Cotton identification and extraction using near infrared sensor and object-oriented spectral segmentation technique].

    Science.gov (United States)

    Deng, Jin-Song; Shi, Yuan-Yuan; Chen, Li-Su; Wang, Ke; Zhu, Jin-Xia

    2009-07-01

    The real-time, effective and reliable method of identifying crop is the foundation of scientific management for crop in the precision agriculture. It is also one of the key techniques for the precision agriculture. However, this expectation cannot be fulfilled by the traditional pixel-based information extraction method with respect to complicated image processing and accurate objective identification. In the present study, visible-near infrared image of cotton was acquired using high-resolution sensor. Object-oriented segmentation technique was performed on the image to produce image objects and spatial/spectral features of cotton. Afterwards, nearest neighbor classifier integrated the spectral, shape and topologic information of image objects to precisely identify cotton according to various features. Finally, 300 random samples and an error matrix were applied to undertake the accuracy assessment of identification. Although errors and confusion exist, this method shows satisfying results with an overall accuracy of 96.33% and a KAPPA coefficient of 0.926 7, which can meet the demand of automatic management and decision-making in precision agriculture.

  13. Detection of Certain Spices Subjected to Gamma Irradiation By Using Thermal Analysis Technique

    International Nuclear Information System (INIS)

    Sayed, M.S.; Ali, H.G.M.; Abdeldaiem, M.H.

    2013-01-01

    The present investigation was carried out to apply a detection method of some irradiated spices using thermal analysis technique. Black pepper, cumin and ginger were irradiated using gamma irradiation at dose levels 5, 10 and 15 kGy and stored for 12 months at room temperature. Thermal analysis techniques TGA and DTA were studied for characterizing irradiated spices. Thermo gravimetric analysis (TGA) is a method where the measurement of mass as a function of heating is recorded. TGA was used to determine the moisture and ash contents and thermal stabilities. Non-significant changes of the weight loss percent due to the irradiation were occurred on the studied spices up to 10 kGy. The weight loss was decreased at the first step up to 100 degree C due to the release of water of hydration. Another sharp decreasing in weight loss percent at the second step 220-300 degree C may be due to volatilization of the sample. The final weight loss weight loss stage up to 500 degree C may be due to burn out the fixed carbon remaining in the sample. As the irradiation dose increased from control up to 15 kGy, the weight loss percent at the dehydration step was decreased. The kinetics of the spices decomposition were studied in order to ascertain the type of weight loss mechanism and calculate the activation energy (E a ). The differential thermal analysis (DTA) of the studied samples showed two main characteristic peaks; endothermic one due to the dehydration process and the second peak may be due to the partial volatilization of the aromatic compounds of the main constituent of the studied spices. It could be concluded that using gamma irradiation (up to 15.0 kGy) for black pepper, cumin and ginger are thermally stable to human consumption.

  14. Mathematical Foundation Based Inter-Connectivity modelling of Thermal Image processing technique for Fire Protection

    Directory of Open Access Journals (Sweden)

    Sayantan Nath

    2015-09-01

    Full Text Available In this paper, integration between multiple functions of image processing and its statistical parameters for intelligent alarming series based fire detection system is presented. The proper inter-connectivity mapping between processing elements of imagery based on classification factor for temperature monitoring and multilevel intelligent alarm sequence is introduced by abstractive canonical approach. The flow of image processing components between core implementation of intelligent alarming system with temperature wise area segmentation as well as boundary detection technique is not yet fully explored in the present era of thermal imaging. In the light of analytical perspective of convolutive functionalism in thermal imaging, the abstract algebra based inter-mapping model between event-calculus supported DAGSVM classification for step-by-step generation of alarm series with gradual monitoring technique and segmentation of regions with its affected boundaries in thermographic image of coal with respect to temperature distinctions is discussed. The connectedness of the multifunctional operations of image processing based compatible fire protection system with proper monitoring sequence is presently investigated here. The mathematical models representing the relation between the temperature affected areas and its boundary in the obtained thermal image defined in partial derivative fashion is the core contribution of this study. The thermal image of coal sample is obtained in real-life scenario by self-assembled thermographic camera in this study. The amalgamation between area segmentation, boundary detection and alarm series are described in abstract algebra. The principal objective of this paper is to understand the dependency pattern and the principles of working of image processing components and structure an inter-connected modelling technique also for those components with the help of mathematical foundation.

  15. A new technique for precise measurement of thermal conductivity of metals at normal and high temperatures

    International Nuclear Information System (INIS)

    Binkele, L.

    1990-09-01

    Theoretical and experimental investigations on a new measuring technique are described; a technique similar to the well known Kohlrausch measuring technique, which is characterized by direct electrical sample heating. Subject of the investigations is a cylindrical metallic sample, 5 mm thick and 200 mm in length, which is positioned vertically between water-cooled clamps in a vacuum container. The sample can be heated using two simultaneously operating current sources, a 50 Hz-source for axial flow (main heating) as well as a 200 kHz-induction source for generating eddy currents in two short regions above and below the sample centre (additional heating). By using two heating sources different symmetrical temperature profiles in a central eddy-current-free area of about ± 10mm can be produced for any given central sample temperature. The last chapter contains thermal conductivity and electrical resistivity measuring curves for Pt, W, Fe, Ni, Ag, Al, Mg, Ir, Ru, Re, Ho and Y in the temperature range 273 to 1500 K representative of all the metals and alloys investigated. In cases where comparisons with published precise conductivity data, established by other measuring techniques in restricted temperature ranges, were posible, the new measuring method is greatly supported (in the case of Pt, W, Ni, Ag, Al). For the Metals Ir, Ru, Re, Ho and Y high temperature thermal conductivity data are given for the first time. (orig./MM) [de

  16. Application of Microextraction Techniques Including SPME and MESI to the Thermal Degradation of Polymers: A Review.

    Science.gov (United States)

    Kaykhaii, Massoud; Linford, Matthew R

    2017-03-04

    Here, we discuss the newly developed micro and solventless sample preparation techniques SPME (Solid Phase Microextraction) and MESI (Membrane Extraction with a Sorbent Interface) as applied to the qualitative and quantitative analysis of thermal oxidative degradation products of polymers and their stabilizers. The coupling of these systems to analytical instruments is also described. Our comprehensive literature search revealed that there is no previously published review article on this topic. It is shown that these extraction techniques are valuable sample preparation tools for identifying complex series of degradation products in polymers. In general, the number of products identified by traditional headspace (HS-GC-MS) is much lower than with SPME-GC-MS. MESI is particularly well suited for the detection of non-polar compounds, therefore number of products identified by this technique is not also to the same degree of SPME. Its main advantage, however, is its ability of (semi-) continuous monitoring, but it is more expensive and not yet commercialized.

  17. Metallographic techniques for evaluation of Thermal Barrier Coatings produced by Electron Beam Physical Vapor Deposition

    International Nuclear Information System (INIS)

    Kelly, Matthew; Singh, Jogender; Todd, Judith; Copley, Steven; Wolfe, Douglas

    2008-01-01

    Thermal Barrier Coatings (TBC) produced by Electron Beam Physical Vapor Deposition (EB-PVD) are primarily applied to critical hot section turbine components. EB-PVD TBC for turbine applications exhibit a complicated structure of porous ceramic columns separated by voids that offers mechanical compliance. Currently there are no standard evaluation methods for evaluating EB-PVD TBC structure quantitatively. This paper proposes a metallographic method for preparing samples and evaluating techniques to quantitatively measure structure. TBC samples were produced and evaluated with the proposed metallographic technique and digital image analysis for columnar grain size and relative intercolumnar porosity. Incorporation of the proposed evaluation technique will increase knowledge of the relation between processing parameters and material properties by incorporating a structural link. Application of this evaluation method will directly benefit areas of quality control, microstructural model development, and reduced development time for process scaling

  18. Search method optimization technique for thermal design of high power RFQ structure

    International Nuclear Information System (INIS)

    Sharma, N.K.; Joshi, S.C.

    2009-01-01

    RRCAT has taken up the development of 3 MeV RFQ structure for the low energy part of 100 MeV H - ion injector linac. RFQ is a precision machined resonating structure designed for high rf duty factor. RFQ structural stability during high rf power operation is an important design issue. The thermal analysis of RFQ has been performed using ANSYS finite element analysis software and optimization of various parameters is attempted using Search Method optimization technique. It is an effective optimization technique for the systems governed by a large number of independent variables. The method involves examining a number of combinations of values of independent variables and drawing conclusions from the magnitude of the objective function at these combinations. In these methods there is a continuous improvement in the objective function throughout the course of the search and hence these methods are very efficient. The method has been employed in optimization of various parameters (called independent variables) of RFQ like cooling water flow rate, cooling water inlet temperatures, cavity thickness etc. involved in RFQ thermal design. The temperature rise within RFQ structure is the objective function during the thermal design. Using ANSYS Programming Development Language (APDL), various multiple iterative programmes are written and the analysis are performed to minimize the objective function. The dependency of the objective function on various independent variables is established and the optimum values of the parameters are evaluated. The results of the analysis are presented in the paper. (author)

  19. Investigation of the Promotion of Wind Power Consumption Using the Thermal-Electric Decoupling Techniques

    Directory of Open Access Journals (Sweden)

    Shuang Rong

    2015-08-01

    Full Text Available In the provinces of north China, combined heat and electric power generations (CHP are widely utilized to provide both heating source and electricity. While, due to the constraint of thermal-electric coupling within CHP, a mass of wind turbines have to offline operate during heating season to maintain the power grid stability. This paper proposes a thermal-electric decoupling (TED approach to release the energy waste. Within the thermal-electric decoupling system, heat storage and electric boiler/heat pump are introduced to provide an auxiliary thermal source during hard peak shaving period, thus relying on the participation of an outside heat source, the artificial electric power output change interval could be widened to adopt more wind power and reduce wind power curtailment. Both mathematic models and methods are proposed to calculate the evaluation indexes to weight the effect of TED, by using the Monte Carlo simulation technique. Numerical simulations have been conducted to demonstrate the effectiveness of the proposed methods, and the results show that the proposed approach could relieve up to approximately 90% of wind power curtailment and the ability of power system to accommodate wind power could be promoted about 32%; moreover, the heating source is extended, about 300 GJ heat could be supplied by TED during the whole heating season, which accounts for about 18% of the total heat need.

  20. Impact of soil water content on landmine detection using radar and thermal infared sensors

    NARCIS (Netherlands)

    Hong, S.-H.; Miller, T.W.; Tobin, H.; Borchers, B.; Hendrickx, J.M.H.; Lensen, H.A.; Schwering, P.B.W.

    2001-01-01

    Land mines are a major problem in many areas of the world. In spite of the fact that many different types of land mines sensors have been developed, the detection of non-metallic land mines remains very difficult. Most landmine detection sensors are affected by soil properties such as water content,

  1. Certification of temperature measuring techniques at thermal and nuclear power plants

    International Nuclear Information System (INIS)

    Preobrazhenskij, V.P.; Strigina, L.A.

    1980-01-01

    Necessity for metrological certification of temperature measurement techniques (TMT) at thermal and nuclear energy plants is grounded. An order of TMT certification is stated and formulae for determining the accuracy of temperature measurements by the thermoelectric method are given. It is concluded that through there are also statistical characteristics of errors of a number of measurement properties, it is necessary to carry on statistical investigations into errors of thermoelectrode extending wires, planimeters, measurement conditions. Such kind investigation technigues have been developed. Besides, it is necessary to regulate a uniform approach to the usage of statistical characteristics of errors of means and conditions of measurements to minimize volume of work for the personnel of thermal and nuclear energy plants and provide reliable estimates of temperature measurement errors

  2. Microstructure and thermal properties of Cu-SiC composite materials depending on the sintering technique

    Directory of Open Access Journals (Sweden)

    Chmielewski Marcin

    2017-01-01

    Full Text Available The presented paper investigates the relationship between the microstructure and thermal properties of copper-silicon carbide composites obtained through hot pressing (HP and spark plasma sintering (SPS techniques. The microstructural analysis showed a better densification in the case of composites sintered in the SPS process. TEM investigations revealed the presence of silicon in the area of metallic matrix in the region close to metal-ceramic boundary. It is the product of silicon dissolving process in copper occurring at an elevated temperature. The Cu-SiC interface is significantly defected in composites obtained through the hot pressing method, which has a major influence on the thermal conductivity of materials.

  3. Thermal-hydraulic analysis techniques for axisymmetric pebble bed nuclear reactor cores

    International Nuclear Information System (INIS)

    Stroh, K.R.

    1979-03-01

    The pebble bed reactor's cylindrical core volume contains a random bed of small, spherical fuel-moderator elements. These graphite spheres, containing a central region of dispersed coated-particle fissile and fertile material, are cooled by high pressure helium flowing through the connected interstitial voids. A mathematical model and numerical solution technique have been developed which allow calculation of macroscopic values of thermal-hydraulic variables in an axisymmetric pebble bed nuclear reactor core. The computer program PEBBLE is based on a mathematical model which treats the bed macroscopically as a generating, conducting porous medium. The steady-state model uses a nonlinear Forchheimer-type relation between the coolant pressure gradient and mass flux, with newly derived coefficients for the linear and quadratic resistance terms. The remaining equations in the model make use of mass continuity, and thermal energy balances for the solid and fluid phases

  4. A technique to measure the thermal diffusivity of high-Tc superconductors

    International Nuclear Information System (INIS)

    Powers, C.E.

    1991-01-01

    High T(sub c) superconducting electrical current leads and ground straps will be used in cryogenic coolers in future NASA Goddard Space Flight Center missions. These superconducting samples are long, thin leads with a typical diameter of two millimeters. A longitudinal method is developed to measure the thermal diffusivity of candidate materials for this application. This technique uses a peltier junction to supply an oscillatory heat wave into one end of a sample and will use low mass thermocouples to follow the heat wave along the sample. The thermal diffusivity is calculated using both the exponential decay of the heat wave and the phase shift to the wave. Measurements are performed in a cryostat between 10 K and room temperature

  5. Image processing techniques for thermal, x-rays and nuclear radiations

    International Nuclear Information System (INIS)

    Chadda, V.K.

    1998-01-01

    The paper describes image acquisition techniques for the non-visible range of electromagnetic spectrum especially thermal, x-rays and nuclear radiations. Thermal imaging systems are valuable tools used for applications ranging from PCB inspection, hot spot studies, fire identification, satellite imaging to defense applications. Penetrating radiations like x-rays and gamma rays are used in NDT, baggage inspection, CAT scan, cardiology, radiography, nuclear medicine etc. Neutron radiography compliments conventional x-rays and gamma radiography. For these applications, image processing and computed tomography are employed for 2-D and 3-D image interpretation respectively. The paper also covers main features of image processing systems for quantitative evaluation of gray level and binary images. (author)

  6. Sensor

    OpenAIRE

    Gleeson, Helen; Dierking, Ingo; Grieve, Bruce; Woodyatt, Christopher; Brimicombe, Paul

    2015-01-01

    An electrical temperature sensor (10) comprises a liquid crystalline material (12). First and second electrically conductive contacts (14), (16), having a spaced relationship there between, contact the liquid crystalline material (12). An electric property measuring device is electrically connected to the first and second contacts (14), (16) and is arranged to measure an electric property of the liquid crystalline material (12). The liquid crystalline material (12) has a transition temperatur...

  7. Highly Sensitive and Wide-Dynamic-Range Multichannel Optical-Fiber pH Sensor Based on PWM Technique.

    Science.gov (United States)

    Khan, Md Rajibur Rahaman; Kang, Shin-Won

    2016-11-09

    In this study, we propose a highly sensitive multichannel pH sensor that is based on an optical-fiber pulse width modulation (PWM) technique. According to the optical-fiber PWM method, the received sensing signal's pulse width changes when the optical-fiber pH sensing-element of the array comes into contact with pH buffer solutions. The proposed optical-fiber PWM pH-sensing system offers a linear sensing response over a wide range of pH values from 2 to 12, with a high pH-sensing ability. The sensitivity of the proposed pH sensor is 0.46 µs/pH, and the correlation coefficient R² is approximately 0.997. Additional advantages of the proposed optical-fiber PWM pH sensor include a short/fast response-time of about 8 s, good reproducibility properties with a relative standard deviation (RSD) of about 0.019, easy fabrication, low cost, small size, reusability of the optical-fiber sensing-element, and the capability of remote sensing. Finally, the performance of the proposed PWM pH sensor was compared with that of potentiometric, optical-fiber modal interferometer, and optical-fiber Fabry-Perot interferometer pH sensors with respect to dynamic range width, linearity as well as response and recovery times. We observed that the proposed sensing systems have better sensing abilities than the above-mentioned pH sensors.

  8. Detection of impact damage on thermal protection systems using thin-film piezoelectric sensors for integrated structural health monitoring

    Science.gov (United States)

    Na, Jeong K.; Kuhr, Samuel J.; Jata, Kumar V.

    2008-03-01

    Thermal Protection Systems (TPS) can be subjected to impact damage during flight and/or during ground maintenance and/or repair. AFRL/RXLP is developing a reliable and robust on-board sensing/monitoring capability for next generation thermal protection systems to detect and assess impact damage. This study was focused on two classes of metallic thermal protection tiles to determine threshold for impact damage and develop sensing capability of the impacts. Sensors made of PVDF piezoelectric film were employed and tested to evaluate the detectability of impact signals and assess the onset or threshold of impact damage. Testing was performed over a range of impact energy levels, where the sensors were adhered to the back of the specimens. The PVDF signal levels were analyzed and compared to assess damage, where digital microscopy, visual inspection, and white light interferometry were used for damage verification. Based on the impact test results, an assessment of the impact damage thresholds for each type of metallic TPS system was made.

  9. Precision of four otolith techniques for estimating age of white perch from a thermally altered reservoir

    Science.gov (United States)

    Snow, Richard A.; Porta, Michael J.; Long, James M.

    2018-01-01

    The White Perch Morone americana is an invasive species in many Midwestern states and is widely distributed in reservoir systems, yet little is known about the species' age structure and population dynamics. White Perch were first observed in Sooner Reservoir, a thermally altered cooling reservoir in Oklahoma, by the Oklahoma Department of Wildlife Conservation in 2006. It is unknown how thermally altered systems like Sooner Reservoir may affect the precision of White Perch age estimates. Previous studies have found that age structures from Largemouth Bass Micropterus salmoides and Bluegills Lepomis macrochirus from thermally altered reservoirs had false annuli, which increased error when estimating ages. Our objective was to quantify the precision of White Perch age estimates using four sagittal otolith preparation techniques (whole, broken, browned, and stained). Because Sooner Reservoir is thermally altered, we also wanted to identify the best month to collect a White Perch age sample based on aging precision. Ages of 569 White Perch (20–308 mm TL) were estimated using the four techniques. Age estimates from broken, stained, and browned otoliths ranged from 0 to 8 years; whole‐view otolith age estimates ranged from 0 to 7 years. The lowest mean coefficient of variation (CV) was obtained using broken otoliths, whereas the highest CV was observed using browned otoliths. July was the most precise month (lowest mean CV) for estimating age of White Perch, whereas April was the least precise month (highest mean CV). These results underscore the importance of knowing the best method to prepare otoliths for achieving the most precise age estimates and the best time of year to obtain those samples, as these factors may affect other estimates of population dynamics.

  10. Sealing of thermally-sprayed stainless steel coatings against corrosion using nickel electroplating technique

    Directory of Open Access Journals (Sweden)

    Hathaipat Koiprasert

    2007-07-01

    Full Text Available Electric arc spraying (EAS is one of the thermal spray techniques used for restoration and to providecorrosion resistance. It can be utilized to build up coatings to thicknesses of several millimeters, It is easy to use on-site. Most importantly, the cost of this technique is lower than other thermal spraying techniques thatmay be suitable for part restoration. A major disadvantage associated with the electric arc sprayed coating is its high porosity, which can be as high as 3-8% making it not appropriate for use in immersion condition. This work was carried out around the idea of using electroplating to seal off the pore of the EAS coating, with an aim to improve the corrosion resistance of the coating in immersion condition. This research compared the corrosion behavior of a stainless steel 316 electric arc sprayed coating in 2M NaOH solution at 25oC. It was found that the Ni plating used as sealant can improve the corrosion resistance of the EAS coating. Furthermore, the smoothened and plated stainless steel 316 coating has a better corrosion resistance than the plated EAS coating that was not ground to smoothen the surface before plating.

  11. Evaluation of relative radiometric correction techniques on Landsat 8 OLI sensor data

    Science.gov (United States)

    Novelli, Antonio; Caradonna, Grazia; Tarantino, Eufemia

    2016-08-01

    The quality of information derived from processed remotely sensed data may depend upon many factors, mostly related to the extent data acquisition is influenced by atmospheric conditions, topographic effects, sun angle and so on. The goal of radiometric corrections is to reduce such effects in order enhance the performance of change detection analysis. There are two approaches to radiometric correction: absolute and relative calibrations. Due to the large amount of free data products available, absolute radiometric calibration techniques may be time consuming and financially expensive because of the necessary inputs for absolute calibration models (often these data are not available and can be difficult to obtain). The relative approach to radiometric correction, known as relative radiometric normalization, is preferred with some research topics because no in situ ancillary data, at the time of satellite overpasses, are required. In this study we evaluated three well known relative radiometric correction techniques using two Landsat 8 - OLI scenes over a subset area of the Apulia Region (southern Italy): the IR-MAD (Iteratively Reweighted Multivariate Alteration Detection), the HM (Histogram Matching) and the DOS (Dark Object Subtraction). IR-MAD results were statistically assessed within a territory with an extremely heterogeneous landscape and all computations performed in a Matlab environment. The panchromatic and thermal bands were excluded from the comparisons.

  12. An Assessment of Polynomial Regression Techniques for the Relative Radiometric Normalization (RRN of High-Resolution Multi-Temporal Airborne Thermal Infrared (TIR Imagery

    Directory of Open Access Journals (Sweden)

    Mir Mustafizur Rahman

    2014-11-01

    Full Text Available Thermal Infrared (TIR remote sensing images of urban environments are increasingly available from airborne and satellite platforms. However, limited access to high-spatial resolution (H-res: ~1 m TIR satellite images requires the use of TIR airborne sensors for mapping large complex urban surfaces, especially at micro-scales. A critical limitation of such H-res mapping is the need to acquire a large scene composed of multiple flight lines and mosaic them together. This results in the same scene components (e.g., roads, buildings, green space and water exhibiting different temperatures in different flight lines. To mitigate these effects, linear relative radiometric normalization (RRN techniques are often applied. However, the Earth’s surface is composed of features whose thermal behaviour is characterized by complexity and non-linearity. Therefore, we hypothesize that non-linear RRN techniques should demonstrate increased radiometric agreement over similar linear techniques. To test this hypothesis, this paper evaluates four (linear and non-linear RRN techniques, including: (i histogram matching (HM; (ii pseudo-invariant feature-based polynomial regression (PIF_Poly; (iii no-change stratified random sample-based linear regression (NCSRS_Lin; and (iv no-change stratified random sample-based polynomial regression (NCSRS_Poly; two of which (ii and iv are newly proposed non-linear techniques. When applied over two adjacent flight lines (~70 km2 of TABI-1800 airborne data, visual and statistical results show that both new non-linear techniques improved radiometric agreement over the previously evaluated linear techniques, with the new fully-automated method, NCSRS-based polynomial regression, providing the highest improvement in radiometric agreement between the master and the slave images, at ~56%. This is ~5% higher than the best previously evaluated linear technique (NCSRS-based linear regression.

  13. A Smart Sensor Data Transmission Technique for Logistics and Intelligent Transportation Systems

    Directory of Open Access Journals (Sweden)

    Kyunghee Sun

    2018-03-01

    Full Text Available When it comes to Internet of Things systems that include both a logistics system and an intelligent transportation system, a smart sensor is one of the key elements to collect useful information whenever and wherever necessary. This study proposes the Smart Sensor Node Group Management Medium Access Control Scheme designed to group smart sensor devices and collect data from them efficiently. The proposed scheme performs grouping of portable sensor devices connected to a system depending on the distance from the sink node and transmits data by setting different buffer thresholds to each group. This method reduces energy consumption of sensor devices located near the sink node and enhances the IoT system’s general energy efficiency. When a sensor device is moved and, thus, becomes unable to transmit data, it is allocated to a new group so that it can continue transmitting data to the sink node.

  14. DE-IDENTIFICATION TECHNIQUE FOR IOT WIRELESS SENSOR NETWORK PRIVACY PROTECTION

    Directory of Open Access Journals (Sweden)

    Yennun Huang

    2017-02-01

    Full Text Available As the IoT ecosystem becoming more and more mature, hardware and software vendors are trying create new value by connecting all kinds of devices together via IoT. IoT devices are usually equipped with sensors to collect data, and the data collected are transmitted over the air via different kinds of wireless connection. To extract the value of the data collected, the data owner may choose to seek for third-party help on data analysis, or even of the data to the public for more insight. In this scenario it is important to protect the released data from privacy leakage. Here we propose that differential privacy, as a de-identification technique, can be a useful approach to add privacy protection to the data released, as well as to prevent the collected from intercepted and decoded during over-the-air transmission. A way to increase the accuracy of the count queries performed on the edge cases in a synthetic database is also presented in this research.

  15. Experimental Study on Rebar Corrosion Using the Galvanic Sensor Combined with the Electronic Resistance Technique

    Science.gov (United States)

    Xu, Yunze; Li, Kaiqiang; Liu, Liang; Yang, Lujia; Wang, Xiaona; Huang, Yi

    2016-01-01

    In this paper, a new kind of carbon steel (CS) and stainless steel (SS) galvanic sensor system was developed for the study of rebar corrosion in different pore solution conditions. Through the special design of the CS and SS electronic coupons, the electronic resistance (ER) method and zero resistance ammeter (ZRA) technique were used simultaneously for the measurement of both the galvanic current and the corrosion depth. The corrosion processes in different solution conditions were also studied by linear polarization resistance (LPR) and the measurements of polarization curves. The test result shows that the galvanic current noise can provide detailed information of the corrosion processes. When localized corrosion occurs, the corrosion rate measured by the ER method is lower than the real corrosion rate. However, the value measured by the LPR method is higher than the real corrosion rate. The galvanic current and the corrosion current measured by the LPR method shows linear correlation in chloride-containing saturated Ca(OH)2 solution. The relationship between the corrosion current differences measured by the CS electronic coupons and the galvanic current between the CS and SS electronic coupons can also be used to evaluate the localized corrosion in reinforced concrete. PMID:27618054

  16. A comparative performance evaluation of intrusion detection techniques for hierarchical wireless sensor networks

    Directory of Open Access Journals (Sweden)

    H.H. Soliman

    2012-11-01

    Full Text Available An explosive growth in the field of wireless sensor networks (WSNs has been achieved in the past few years. Due to its important wide range of applications especially military applications, environments monitoring, health care application, home automation, etc., they are exposed to security threats. Intrusion detection system (IDS is one of the major and efficient defensive methods against attacks in WSN. Therefore, developing IDS for WSN have attracted much attention recently and thus, there are many publications proposing new IDS techniques or enhancement to the existing ones. This paper evaluates and compares the most prominent anomaly-based IDS systems for hierarchical WSNs and identifying their strengths and weaknesses. For each IDS, the architecture and the related functionality are briefly introduced, discussed, and compared, focusing on both the operational strengths and weakness. In addition, a comparison of the studied IDSs is carried out using a set of critical evaluation metrics that are divided into two groups; the first one related to performance and the second related to security. Finally based on the carried evaluation and comparison, a set of design principles are concluded, which have to be addressed and satisfied in future research of designing and implementing IDS for WSNs.

  17. Experimental Study on Rebar Corrosion Using the Galvanic Sensor Combined with the Electronic Resistance Technique

    Directory of Open Access Journals (Sweden)

    Yunze Xu

    2016-09-01

    Full Text Available In this paper, a new kind of carbon steel (CS and stainless steel (SS galvanic sensor system was developed for the study of rebar corrosion in different pore solution conditions. Through the special design of the CS and SS electronic coupons, the electronic resistance (ER method and zero resistance ammeter (ZRA technique were used simultaneously for the measurement of both the galvanic current and the corrosion depth. The corrosion processes in different solution conditions were also studied by linear polarization resistance (LPR and the measurements of polarization curves. The test result shows that the galvanic current noise can provide detailed information of the corrosion processes. When localized corrosion occurs, the corrosion rate measured by the ER method is lower than the real corrosion rate. However, the value measured by the LPR method is higher than the real corrosion rate. The galvanic current and the corrosion current measured by the LPR method shows linear correlation in chloride-containing saturated Ca(OH2 solution. The relationship between the corrosion current differences measured by the CS electronic coupons and the galvanic current between the CS and SS electronic coupons can also be used to evaluate the localized corrosion in reinforced concrete.

  18. Evaluation of electrode surface modification techniques for the development of chemical sensors

    International Nuclear Information System (INIS)

    Galiatsatos, C.

    1988-01-01

    This thesis covers several aspects of electrode surface modification techniques. The successful application of gamma-radiation to create polymer-coated electrodes, where the polymers can be ion exchangers and consequently of great analytical interest by themselves (such as the polymer poly(diallyl) dimethyl ammonium chloride) or where some other neutral polymers can function as convenient matrices for the introduction of biomolecules and/or other electrochemically interesting species is reported. This is demonstrated by using the neutral polymer poly(vinyl alcohol) (PVAL) as a matrix for immobilization of the enzyme glucose oxidase and the mediator methyl viologen. The effect of γ-radiation on PVAL is discussed, as well as swelling properties of the irradiated polymers and specific characteristics of the created chemical sensors. Results of an experiment where the various kinds of interactions between the ion-exchange polymer Nafion and some positively charged species are explored are reported, and a model system for competition (methyl viologen vs. ruthenium hexaamine) which increases significantly our understanding of the interaction is mentioned. The effect of γ-radiation on Nafion and its ion-exchange compabilities is discussed also. A system of conduction polymers primarily polypyrrole, used as a detector of electroinactive anions due to their doping-undergoing in the film is discussed. Preliminary results on a new method that involves chemical cross-linking of a triisocyane molecule with -OH containing polymers in the presence of enzymes are reported

  19. Visible Watermarking Technique Based on Human Visual System for Single Sensor Digital Cameras

    Directory of Open Access Journals (Sweden)

    Hector Santoyo-Garcia

    2017-01-01

    Full Text Available In this paper we propose a visible watermarking algorithm, in which a visible watermark is embedded into the Bayer Colour Filter Array (CFA domain. The Bayer CFA is the most common raw image representation for images captured by single sensor digital cameras equipped in almost all mobile devices. In proposed scheme, the captured image is watermarked before it is compressed and stored in the storage system. Then this method enforces the rightful ownership of the watermarked image, since there is no other version of the image rather than the watermarked one. We also take into consideration the Human Visual System (HVS so that the proposed technique provides desired characteristics of a visible watermarking scheme, such that the embedded watermark is sufficiently perceptible and at same time not obtrusive in colour and grey-scale images. Unlike other Bayer CFA domain visible watermarking algorithms, in which only binary watermark pattern is supported, proposed watermarking algorithm allows grey-scale and colour images as watermark patterns. It is suitable for advertisement purpose, such as digital library and e-commerce, besides copyright protection.

  20. Study of thermal transitions in polymers by a multifrequency modulated DSC technique

    OpenAIRE

    Fraga Rivas, Iria

    2010-01-01

    Premi extraordinari doctorat curs 2009-2010, àmbit de Ciències Differential Scanning Calorimetry (DSC) is one of the most widely used thermal analysis techniques for the study of transitions and relaxation processes in polymers and also in other materials. It measures the heat flow as a function of time and/or temperature, and determines the energy released or absorbed by a sample when it is heated (cooled) or maintained at a constant temperature. Its advantages are that it is fast a...

  1. Simple technique to evaluate the thermal lens strength of a laser material. SAIP 2005 Talk C-20

    CSIR Research Space (South Africa)

    Esser, D

    2005-01-01

    Full Text Available The presentation is about the simple technique to measure the thermal lens; Same pumping conditions as real laser; Same cooling configuration as real laser; Comparative experiment made; Nd:YVO4 has smaller thermal lens than Nd:GdVO4; Nd:GdVO4 has...

  2. Development and application of thermal cutting techniques during Phase 1 decommissioning of WAGR

    International Nuclear Information System (INIS)

    White, S.J.

    1992-01-01

    The Windscale Advanced Gas Cooled Reactor is the UK's lead Stage 3 Decommissioning Project. One of the main objectives of the project is to demonstrate that a nuclear reactor can be safely and effectively decommissioned to a greenfield site using existing technology. Techniques using thermal cutting processes are used widely in industry and have been successfully adapted and applied to the first phase of the dismantling project. Over 1000 operational cuts have been performed using plasma cutting technology. Oxypropane and thermic lancing technique have also been applied to the dismantling the Top Biological Shield and Top Dome of the reactor pressure vessel. This paper describes the development and application of these standard technologies to the task of decommissioning a nuclear reactor. (Author)

  3. System on chip thermal vacuum sensor based on standard CMOS process

    International Nuclear Information System (INIS)

    Li Jinfeng; Tang Zhenan; Wang Jiaqi

    2009-01-01

    An on-chip microelectromechanical system was fabricated in a 0.5 μm standard CMOS process for gas pressure detection. The sensor was based on a micro-hotplate (MHP) and had been integrated with a rail to rail operational amplifier and an 8-bit successive approximation register (SAR) A/D converter. A tungsten resistor was manufactured on the MHP as the sensing element, and the sacrificial layer of the sensor was made from polysilicon and etched by surface-micromachining technology. The operational amplifier was configured to make the sensor operate in constant current mode. A digital bit stream was provided as the system output. The measurement results demonstrate that the gas pressure sensitive range of the vacuum sensor extends from 1 to 10 5 Pa. In the gas pressure range from 1 to 100 Pa, the sensitivity of the sensor is 0.23 mV/ Pa, the linearity is 4.95%, and the hysteresis is 8.69%. The operational amplifier can drive 200 ω resistors distortionlessly, and the SAR A/D converter achieves a resolution of 7.4 bit with 100 kHz sample rate. The performance of the operational amplifier and the SAR A/D converter meets the requirements of the sensor system.

  4. Manufacture of micro fluidic devices by laser welding using thermal transfer printing techniques

    Science.gov (United States)

    Klein, R.; Klein, K. F.; Tobisch, T.; Thoelken, D.; Belz, M.

    2016-03-01

    Micro-fluidic devices are widely used today in the areas of medical diagnostics and drug research, as well as for applications within the process, electronics and chemical industry. Microliters of fluids or single cell to cell interactions can be conveniently analyzed with such devices using fluorescence imaging, phase contrast microscopy or spectroscopic techniques. Typical micro-fluidic devices consist of a thermoplastic base component with chambers and channels covered by a hermetic fluid and gas tight sealed lid component. Both components are usually from the same or similar thermoplastic material. Different mechanical, adhesive or thermal joining processes can be used to assemble base component and lid. Today, laser beam welding shows the potential to become a novel manufacturing opportunity for midsize and large scale production of micro-fluidic devices resulting in excellent processing quality by localized heat input and low thermal stress to the device during processing. For laser welding, optical absorption of the resin and laser wavelength has to be matched for proper joining. This paper will focus on a new approach to prepare micro-fluidic channels in such devices using a thermal transfer printing process, where an optical absorbing layer absorbs the laser energy. Advantages of this process will be discussed in combination with laser welding of optical transparent micro-fluidic devices.

  5. USING HOT WIRE TECHNIQUE FOR MEASURING THERMAL CONDUCTIVITY OF INFUSIONS OF ORGANIC AND CONVENTIONAL COFFEE

    Directory of Open Access Journals (Sweden)

    Fernando Gordillo-Delgado

    2016-07-01

    Full Text Available The technique of hot wire, a versatile method of low cost and high accuracy for measuring the thermal conductivity of fluids through the increasing temperature of a wire that is immersed into the liquid and between its ends a potential difference is abruptly applied. Using well-known conductivity liquids: water, ethylene glycol and glycerine, the system was tested and calibrated. In this work, this procedure was used to measure the thermal conductivity of the infusion samples of organic and conventional coffee. The same roast degree of the beans was verified with a colorimeter and the preparation was made by pressing 22g of coffee powder in 110mL of water. The obtained data were subjected to Analysis of Variance (ANOVA and this confirmed that the differences in the thermophysical parameter in the two samples are significant with a confidence level of 95\\%. On this way, it was proved that the thermal conductivity value of the coffee infusion allows differentiate between organic and conventional coffee.

  6. Time-Separating Heating and Sensor Functions of Thermistors in Precision Thermal Control Applications

    Science.gov (United States)

    Cho, Hyung J.; Sukhatme, Kalyani G.; Mahoney, John C.; Penanen, Konstantin Penanen; Vargas, Rudolph, Jr.

    2010-01-01

    A method allows combining the functions of a heater and a thermometer in a single device, a thermistor, with minimal temperature read errors. Because thermistors typically have a much smaller thermal mass than the objects they monitor, the thermal time to equilibrate the thermometer to the temperature of the object is typically much shorter than the thermal time of the object to change its temperature in response to an external perturbation.

  7. New Technique for TOC Estimation Based on Thermal Core Logging in Low-Permeable Formations (Bazhen fm.)

    Science.gov (United States)

    Popov, Evgeny; Popov, Yury; Spasennykh, Mikhail; Kozlova, Elena; Chekhonin, Evgeny; Zagranovskaya, Dzhuliya; Belenkaya, Irina; Alekseev, Aleksey

    2016-04-01

    A practical method of organic-rich intervals identifying within the low-permeable dispersive rocks based on thermal conductivity measurements along the core is presented. Non-destructive non-contact thermal core logging was performed with optical scanning technique on 4 685 full size core samples from 7 wells drilled in four low-permeable zones of the Bazhen formation (B.fm.) in the Western Siberia (Russia). The method employs continuous simultaneous measurements of rock anisotropy, volumetric heat capacity, thermal anisotropy coefficient and thermal heterogeneity factor along the cores allowing the high vertical resolution (of up to 1-2 mm). B.fm. rock matrix thermal conductivity was observed to be essentially stable within the range of 2.5-2.7 W/(m*K). However, stable matrix thermal conductivity along with the high thermal anisotropy coefficient is characteristic for B.fm. sediments due to the low rock porosity values. It is shown experimentally that thermal parameters measured relate linearly to organic richness rather than to porosity coefficient deviations. Thus, a new technique employing the transformation of the thermal conductivity profiles into continuous profiles of total organic carbon (TOC) values along the core was developed. Comparison of TOC values, estimated from the thermal conductivity values, with experimental pyrolytic TOC estimations of 665 samples from the cores using the Rock-Eval and HAWK instruments demonstrated high efficiency of the new technique for the organic rich intervals separation. The data obtained with the new technique are essential for the SR hydrocarbon generation potential, for basin and petroleum system modeling application, and estimation of hydrocarbon reserves. The method allows for the TOC richness to be accurately assessed using the thermal well logs. The research work was done with financial support of the Russian Ministry of Education and Science (unique identification number RFMEFI58114X0008).

  8. Thermal dependence of ultrasound contrast agents scattering efficiency for echographic imaging techniques

    Science.gov (United States)

    Biagioni, Angelo; Bettucci, Andrea; Passeri, Daniele; Alippi, Adriano

    2015-06-01

    Ultrasound contrast agents are used in echographic imaging techniques to enhance image contrast. In addition, they may represent an interesting solution to the problem of non-invasive temperature monitoring inside the human body, based on some thermal variations of their physical properties. Contrast agents, indeed, are inserted into blood circulation and they reach the most important organs inside the human body; consequently, any thermometric property that they may possess, could be exploited for realizing a non-invasive thermometer. They essentially are a suspension of microbubbles containing a gas enclosed in a phospholipid membrane; temperature variations induce structural modifications of the microbubble phospholipid shell, thus causing thermal dependence of contrast agent's elastic characteristics. In this paper, the acoustic scattering efficiency of a bulk suspension of of SonoVue® (Bracco SpA Milan, Italy) has been studied using a pulse-echo technique in the frequency range 1-17 MHz, as it depends upon temperatures between 25 and 65°C. Experimental data confirm that the ultrasonic attenuation coefficient of SonoVue® depends on temperature between 25 and 60°C. Chemical composition of the bubble shell seem to support the hypothesis that a phase transition in the microstructure of lipid-coated microbubbles could play a key role in explaining such effect.

  9. n⁺ GaAs/AuGeNi-Au Thermocouple-Type RF MEMS Power Sensors Based on Dual Thermal Flow Paths in GaAs MMIC.

    Science.gov (United States)

    Zhang, Zhiqiang; Liao, Xiaoping

    2017-06-17

    To achieve radio frequency (RF) power detection, gain control, and circuit protection, this paper presents n⁺ GaAs/AuGeNi-Au thermocouple-type RF microelectromechanical system (MEMS) power sensors based on dual thermal flow paths. The sensors utilize a conversion principle of RF power-heat-voltage, where a thermovoltage is obtained as the RF power changes. To improve the heat transfer efficiency and the sensitivity, structures of two heat conduction paths are designed: one in which a thermal slug of Au is placed between two load resistors and hot junctions of the thermocouples, and one in which a back cavity is fabricated by the MEMS technology to form a substrate membrane underneath the resistors and the hot junctions. The improved sensors were fabricated by a GaAs monolithic microwave integrated circuit (MMIC) process. Experiments show that these sensors have reflection losses of less than -17 dB up to 12 GHz. At 1, 5, and 10 GHz, measured sensitivities are about 63.45, 53.97, and 44.14 µ V/mW for the sensor with the thermal slug, and about 111.03, 94.79, and 79.04 µ V/mW for the sensor with the thermal slug and the back cavity, respectively.

  10. n+ GaAs/AuGeNi-Au Thermocouple-Type RF MEMS Power Sensors Based on Dual Thermal Flow Paths in GaAs MMIC

    Directory of Open Access Journals (Sweden)

    Zhiqiang Zhang

    2017-06-01

    Full Text Available To achieve radio frequency (RF power detection, gain control, and circuit protection, this paper presents n+ GaAs/AuGeNi-Au thermocouple-type RF microelectromechanical system (MEMS power sensors based on dual thermal flow paths. The sensors utilize a conversion principle of RF power-heat-voltage, where a thermovoltage is obtained as the RF power changes. To improve the heat transfer efficiency and the sensitivity, structures of two heat conduction paths are designed: one in which a thermal slug of Au is placed between two load resistors and hot junctions of the thermocouples, and one in which a back cavity is fabricated by the MEMS technology to form a substrate membrane underneath the resistors and the hot junctions. The improved sensors were fabricated by a GaAs monolithic microwave integrated circuit (MMIC process. Experiments show that these sensors have reflection losses of less than −17 dB up to 12 GHz. At 1, 5, and 10 GHz, measured sensitivities are about 63.45, 53.97, and 44.14 µV/mW for the sensor with the thermal slug, and about 111.03, 94.79, and 79.04 µV/mW for the sensor with the thermal slug and the back cavity, respectively.

  11. An air flow sensor for neonatal mechanical ventilation applications based on a novel fiber-optic sensing technique.

    Science.gov (United States)

    Battista, L; Sciuto, S A; Scorza, A

    2013-03-01

    In this work, a simple and low-cost air flow sensor, based on a novel fiber-optic sensing technique has been developed for monitoring air flows rates supplied by a neonatal ventilator to support infants in intensive care units. The device is based on a fiber optic sensing technique allowing (a) the immunity to light intensity variations independent by measurand and (b) the reduction of typical shortcomings affecting all biomedical fields (electromagnetic interference and patient electrical safety). The sensing principle is based on the measurement of transversal displacement of an emitting fiber-optic cantilever due to action of air flow acting on it; the fiber tip displacement is measured by means of a photodiode linear array, placed in front of the entrance face of the emitting optical fiber in order to detect its light intensity profile. As the measurement system is based on a detection of the illumination pattern, and not on an intensity modulation technique, it results less sensitive to light intensity fluctuation independent by measurand than intensity-based sensors. The considered technique is here adopted in order to develop two different configurations for an air flow sensor suitable for the measurement of air flow rates typically occurring during mechanical ventilation of newborns: a mono-directional and a bi-directional transducer have been proposed. A mathematical model for the air flow sensor is here proposed and a static calibration of two different arrangements has been performed: a measurement range up to 3.00 × 10(-4) m(3)∕s (18.0 l∕min) for the mono-directional sensor and a measurement range of ±3.00 × 10(-4) m(3)∕s (±18.0 l∕min) for the bi-directional sensor are experimentally evaluated, according to the air flow rates normally encountered during tidal breathing of infants with a mass lower than 10 kg. Experimental data of static calibration result in accordance with the proposed theoretical model: for the mono

  12. Signal processing techniques for damage detection with piezoelectric wafer active sensors and embedded ultrasonic structural radar

    Science.gov (United States)

    Yu, Lingyu; Bao, Jingjing; Giurgiutiu, Victor

    2004-07-01

    Embedded ultrasonic structural radar (EUSR) algorithm is developed for using piezoelectric wafer active sensor (PWAS) array to detect defects within a large area of a thin-plate specimen. Signal processing techniques are used to extract the time of flight of the wave packages, and thereby to determine the location of the defects with the EUSR algorithm. In our research, the transient tone-burst wave propagation signals are generated and collected by the embedded PWAS. Then, with signal processing, the frequency contents of the signals and the time of flight of individual frequencies are determined. This paper starts with an introduction of embedded ultrasonic structural radar algorithm. Then we will describe the signal processing methods used to extract the time of flight of the wave packages. The signal processing methods being used include the wavelet denoising, the cross correlation, and Hilbert transform. Though hardware device can provide averaging function to eliminate the noise coming from the signal collection process, wavelet denoising is included to ensure better signal quality for the application in real severe environment. For better recognition of time of flight, cross correlation method is used. Hilbert transform is applied to the signals after cross correlation in order to extract the envelope of the signals. Signal processing and EUSR are both implemented by developing a graphical user-friendly interface program in LabView. We conclude with a description of our vision for applying EUSR signal analysis to structural health monitoring and embedded nondestructive evaluation. To this end, we envisage an automatic damage detection application utilizing embedded PWAS, EUSR, and advanced signal processing.

  13. A Sensor-less Method for Online Thermal Monitoring of Switched Reluctance Machine

    DEFF Research Database (Denmark)

    Wang, Chao; Liu, Hui; Liu, Xiao

    2015-01-01

    Stator winding is one of the most vulnerable parts in Switched Reluctance Machine (SRM), especially under thermal stresses during frequently changing operation circumstances and susceptible heat dissipation conditions. Thus real-time online thermal monitoring of the stator winding is of great sig...

  14. Plasma arc and thermal lance techniques for cutting concrete and steel

    International Nuclear Information System (INIS)

    Bargagliotti, A.; Caprile, L.; Piana, F.; Tolle, E.

    1986-01-01

    The plasma arc technique is used today in industrial practice for any metal, but mainly for cutting stainless steel, carbon steel and aluminium. In air the maximum thickness that was cut in the performed tests was 150 mm, both with ferritic and austenitic steel. Underwater the maximum thickness cut was 103 mm. The two types of torch used in the tests are those used today: the plasma-shaped electrode torch (WIPC) and the pointed electrode torch (DMC-GRUEN). Two different types of gas were compared: an argon-nitrogen mixture and an argon-hydrogen mixture. The second mixture adopted results in less dust emission. The production of dust and aerosols also depends on the cutting speed, on the kind of steel, but mainly on the environmental conditions; it is reduced up to 500 times under water. Dust and aerosols can, jeopardize the efficiency of the system; moreover, the ambient air can have high-level radiation fields. Indirect and direct protections are needed (shields, remote control, robots, etc.). Tentative procedures for dismantling two types of BWR reactor are examined. Two series of tests demonstrated the feasibility of cutting the most geometrically difficult parts of the reactor internals. The thermal lance technique is used in industrial practice mainly for dismantling large reinforced concrete structures. This technique can be applied to dismantle nuclear facilities, even though it can cause some problems due to the gases, fumes and lapilli produced. In addition, the cost of this technique seems to be generally higher than the cost of other techniques. From the analyses done, the conclusion seems that both the above techniques are feasible for dismantling a nuclear power plant (NPP). The best solution is probably to analyse the different dismantling possibilities and problems and problems of each case

  15. Sensing Properties of a Novel Temperature Sensor Based on Field Assisted Thermal Emission

    Directory of Open Access Journals (Sweden)

    Zhigang Pan

    2017-02-01

    Full Text Available The existing temperature sensors using carbon nanotubes (CNTs are limited by low sensitivity, complicated processes, or dependence on microscopy to observe the experimental results. Here we report the fabrication and successful testing of an ionization temperature sensor featuring non-self-sustaining discharge. The sharp tips of nanotubes generate high electric fields at relatively low voltages, lowering the work function of electrons emitted by CNTs, and thereby enabling the safe operation of such sensors. Due to the temperature effect on the electron emission of CNTs, the collecting current exhibited an exponential increase with temperature rising from 20 °C to 100 °C. Additionally, a higher temperature coefficient of 0.04 K−1 was obtained at 24 V voltage applied on the extracting electrode, higher than the values of other reported CNT-based temperature sensors. The triple-electrode ionization temperature sensor is easy to fabricate and converts the temperature change directly into an electrical signal. It shows a high temperature coefficient and good application potential.

  16. Highly selective gas sensor arrays based on thermally reduced graphene oxide.

    Science.gov (United States)

    Lipatov, Alexey; Varezhnikov, Alexey; Wilson, Peter; Sysoev, Victor; Kolmakov, Andrei; Sinitskii, Alexander

    2013-06-21

    The electrical properties of reduced graphene oxide (rGO) have been previously shown to be very sensitive to surface adsorbates, thus making rGO a very promising platform for highly sensitive gas sensors. However, poor selectivity of rGO-based gas sensors remains a major problem for their practical use. In this paper, we address the selectivity problem by employing an array of rGO-based integrated sensors instead of focusing on the performance of a single sensing element. Each rGO-based device in such an array has a unique sensor response due to the irregular structure of rGO films at different levels of organization, ranging from nanoscale to macroscale. The resulting rGO-based gas sensing system could reliably recognize analytes of nearly the same chemical nature. In our experiments rGO-based sensor arrays demonstrated a high selectivity that was sufficient to discriminate between different alcohols, such as methanol, ethanol and isopropanol, at a 100% success rate. We also discuss a possible sensing mechanism that provides the basis for analyte differentiation.

  17. Seasonal differences in the subjective assessment of outdoor thermal conditions and the impact of analysis techniques on the obtained results

    Science.gov (United States)

    Kántor, Noémi; Kovács, Attila; Takács, Ágnes

    2016-11-01

    Wide research attention has been paid in the last two decades to the thermal comfort conditions of different outdoor and semi-outdoor urban spaces. Field studies were conducted in a wide range of geographical regions in order to investigate the relationship between the thermal sensation of people and thermal comfort indices. Researchers found that the original threshold values of these indices did not describe precisely the actual thermal sensation patterns of subjects, and they reported neutral temperatures that vary among nations and with time of the year. For that reason, thresholds of some objective indices were rescaled and new thermal comfort categories were defined. This research investigates the outdoor thermal perception patterns of Hungarians regarding the Physiologically Equivalent Temperature ( PET) index, based on more than 5800 questionnaires. The surveys were conducted in the city of Szeged on 78 days in spring, summer, and autumn. Various, frequently applied analysis approaches (simple descriptive technique, regression analysis, and probit models) were adopted to reveal seasonal differences in the thermal assessment of people. Thermal sensitivity and neutral temperatures were found to be significantly different, especially between summer and the two transient seasons. Challenges of international comparison are also emphasized, since the results prove that neutral temperatures obtained through different analysis techniques may be considerably different. The outcomes of this study underline the importance of the development of standard measurement and analysis methodologies in order to make future studies comprehensible, hereby facilitating the broadening of the common scientific knowledge about outdoor thermal comfort.

  18. Testing of a Wireless Sensor System for Instrumented Thermal Protection Systems

    Science.gov (United States)

    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.

  19. Advanced data visualization and sensor fusion: Conversion of techniques from medical imaging to Earth science

    Science.gov (United States)

    Savage, Richard C.; Chen, Chin-Tu; Pelizzari, Charles; Ramanathan, Veerabhadran

    1993-01-01

    Hughes Aircraft Company and the University of Chicago propose to transfer existing medical imaging registration algorithms to the area of multi-sensor data fusion. The University of Chicago's algorithms have been successfully demonstrated to provide pixel by pixel comparison capability for medical sensors with different characteristics. The research will attempt to fuse GOES (Geostationary Operational Environmental Satellite), AVHRR (Advanced Very High Resolution Radiometer), and SSM/I (Special Sensor Microwave Imager) sensor data which will benefit a wide range of researchers. The algorithms will utilize data visualization and algorithm development tools created by Hughes in its EOSDIS (Earth Observation SystemData/Information System) prototyping. This will maximize the work on the fusion algorithms since support software (e.g. input/output routines) will already exist. The research will produce a portable software library with documentation for use by other researchers.

  20. The development of sensors and techniques for in situ water quality monitoring

    Science.gov (United States)

    Liu, C. C.

    1976-01-01

    Enzyme electrodes and chloride ion electrodes were investigated for in situ monitoring of water quality. Preliminary results show that miniature chloride ion electrodes and a phenol sensor are most promising in determining trace contaminants in water.

  1. Proximity gettering technology for advanced CMOS image sensors using carbon cluster ion-implantation technique. A review

    Energy Technology Data Exchange (ETDEWEB)

    Kurita, Kazunari; Kadono, Takeshi; Okuyama, Ryousuke; Shigemastu, Satoshi; Hirose, Ryo; Onaka-Masada, Ayumi; Koga, Yoshihiro; Okuda, Hidehiko [SUMCO Corporation, Saga (Japan)

    2017-07-15

    A new technique is described for manufacturing advanced silicon wafers with the highest capability yet reported for gettering transition metallic, oxygen, and hydrogen impurities in CMOS image sensor fabrication processes. Carbon and hydrogen elements are localized in the projection range of the silicon wafer by implantation of ion clusters from a hydrocarbon molecular gas source. Furthermore, these wafers can getter oxygen impurities out-diffused to device active regions from a Czochralski grown silicon wafer substrate to the carbon cluster ion projection range during heat treatment. Therefore, they can reduce the formation of transition metals and oxygen-related defects in the device active regions and improve electrical performance characteristics, such as the dark current, white spot defects, pn-junction leakage current, and image lag characteristics. The new technique enables the formation of high-gettering-capability sinks for transition metals, oxygen, and hydrogen impurities under device active regions of CMOS image sensors. The wafers formed by this technique have the potential to significantly improve electrical devices performance characteristics in advanced CMOS image sensors. (copyright 2017 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  2. Effective evaluation of privacy protection techniques in visible and thermal imagery

    Science.gov (United States)

    Nawaz, Tahir; Berg, Amanda; Ferryman, James; Ahlberg, Jörgen; Felsberg, Michael

    2017-09-01

    Privacy protection may be defined as replacing the original content in an image region with a (less intrusive) content having modified target appearance information to make it less recognizable by applying a privacy protection technique. Indeed, the development of privacy protection techniques also needs to be complemented with an established objective evaluation method to facilitate their assessment and comparison. Generally, existing evaluation methods rely on the use of subjective judgments or assume a specific target type in image data and use target detection and recognition accuracies to assess privacy protection. An annotation-free evaluation method that is neither subjective nor assumes a specific target type is proposed. It assesses two key aspects of privacy protection: "protection" and "utility." Protection is quantified as an appearance similarity, and utility is measured as a structural similarity between original and privacy-protected image regions. We performed an extensive experimentation using six challenging datasets (having 12 video sequences), including a new dataset (having six sequences) that contains visible and thermal imagery. The new dataset is made available online for the community. We demonstrate effectiveness of the proposed method by evaluating six image-based privacy protection techniques and also show comparisons of the proposed method over existing methods.

  3. Intelligent pressure measurement in multiple sensor arrays

    International Nuclear Information System (INIS)

    Matthews, C.A.

    1995-01-01

    Pressure data acquisition has typically consisted of a group of sensors scanned by an electronic or mechanical multiplexer. The data accuracy was dependent upon the temperature stability of the sensors. This paper describes a new method of pressure measurement that combines individual temperature compensated pressure sensors, a microprocessor, and an A/D converter in one module. Each sensor has its own temperature characteristics stored in a look-up table to minimize sensor thermal errors. The result is an intelligent pressure module that can output temperature compensated engineering units over an Ethernet interface. Calibration intervals can be dramatically extended depending upon system accuracy requirements and calibration techniques used

  4. Vacuum behavior and control of a MEMS stage with integrated thermal displacement sensor

    NARCIS (Netherlands)

    Krijnen, B.; Brouwer, Dannis Michel; Abelmann, Leon; Herder, Justus Laurens

    2015-01-01

    We investigate the applicability of a MEMS stage in a vacuum environment. The stage is suspended by a flexure mechanism and is actuated by electrostatic comb-drives. The position of the stage is measured by an integrated sensor based on the conductance of heat through air. The vacuum behavior of the

  5. Simulation of at-sensor radiance over land for proposed thermal ...

    Indian Academy of Sciences (India)

    Satellite level at-sensor radiance corresponding to all four infrared channels of. INSAT-3D Imager payload is .... its heritage traces back to LOWTRAN. MOD-. TRAN includes all ... over tropical region (SeeBor dataset) are car- ried out with the ...

  6. Highly Sensitive and Wide-Dynamic-Range Multichannel Optical-Fiber pH Sensor Based on PWM Technique

    Science.gov (United States)

    Khan, Md. Rajibur Rahaman; Kang, Shin-Won

    2016-01-01

    In this study, we propose a highly sensitive multichannel pH sensor that is based on an optical-fiber pulse width modulation (PWM) technique. According to the optical-fiber PWM method, the received sensing signal’s pulse width changes when the optical-fiber pH sensing-element of the array comes into contact with pH buffer solutions. The proposed optical-fiber PWM pH-sensing system offers a linear sensing response over a wide range of pH values from 2 to 12, with a high pH-sensing ability. The sensitivity of the proposed pH sensor is 0.46 µs/pH, and the correlation coefficient R2 is approximately 0.997. Additional advantages of the proposed optical-fiber PWM pH sensor include a short/fast response-time of about 8 s, good reproducibility properties with a relative standard deviation (RSD) of about 0.019, easy fabrication, low cost, small size, reusability of the optical-fiber sensing-element, and the capability of remote sensing. Finally, the performance of the proposed PWM pH sensor was compared with that of potentiometric, optical-fiber modal interferometer, and optical-fiber Fabry–Perot interferometer pH sensors with respect to dynamic range width, linearity as well as response and recovery times. We observed that the proposed sensing systems have better sensing abilities than the above-mentioned pH sensors. PMID:27834865

  7. Theoretical description of the photopyroelectric technique in the slanted detector configuration for thermal diffusivity measurements in fluids

    International Nuclear Information System (INIS)

    Rojas-Trigos, J.B.; Marín, E.; Mansanares, A.M.; Cedeño, E.; Juárez-Gracia, G.; Calderón, A.

    2014-01-01

    Highlights: • A model for photopyroelectric thermal characterization of fluids is presented. • A slanted detector configuration is considered with a finite measurement cell. • The mean temperature distribution in the photopyroelectric detector, as function of the beam spot position, is calculated. • The influence of the excitation beam spot size, the thermal diffusion length and size of the sample is discussed. • The high lateral resolution of the method observed in experiments is explain. - Abstract: This work presents an extended description about the theoretical aspects related to the generation of the photopyroelectric signal in a recently proposed wedge-like heat transmission detection configuration, which recreates the well-known Angstrom method (widely used for solid samples) for accurate thermal diffusivity measurement in gases and liquids. The presented model allows for the calculation of the temperature profile detected by the pyroelectric sensor as a function of the excitation beam position, and the study of the influence on it of several parameters, such as spot size, thermal properties of the absorber layer, and geometrical parameters of the measurement cell. Through computer simulations, it has been demonstrated that a narrow temperature distribution is created at the sensor surface, independently of the lateral diffusion of heat taking place at the sample's surface

  8. Techniques of thermal energy conservation; Tecnicas de conservacion de la energia termica

    Energy Technology Data Exchange (ETDEWEB)

    Caltenco Estevez, Juan Luis; Roblez Lopez, Francisco; Ceballos Serna, Andres Alberto [Instituto Mexicano del Petroleo (Mexico)

    1996-07-01

    In modern industry the thermal energy is the energy more intensely used, which implies that in the processes and equipment that operate based on it, rely the greatest opportunities for saving . In this paper some saving and conservation techniques of thermal energy, which nowadays have been developed, are presented, whose application has helped to the successful attainment of the objectives of increased productivity of industrial plants, with the additional benefit of reducing the environmental impact of the production activities. [Spanish] En la industria moderna la energia termica es la forma de energia mas intensamente utilizada, lo cual implica que en los procesos y equipos que operan basandose en esta, residan las mayores oportunidades de ahorro. En este trabajo se presentan algunas de las tecnicas de ahorro y conservacion de energia termica, que hoy en dia se han desarrollado, cuya aplicacion ha coadyuvado a la consecucion exitosa de los objetivos de incremento de la productividad de plantas industriales, con el beneficio adicional de reducir el impacto ambiental de las actividades productivas.

  9. Microstructural Improvement of Hydroxyapatite-ZrO2 Composite Ceramics via Thermal Precipitation Techniques.

    Science.gov (United States)

    Sangmala, A.; Limsuwan, P.; Kaewwiset, W.; Naemchanthara, K.

    2017-09-01

    Hydroxyapatite-ZrO2 composite ceramic were synthesized using a thermal precipitation techniques. The chemical precursors were prepared from di-ammonium hydrogen orthophosphate, calcium oxide (CaO) derived from chicken eggshell, zirconium dioxide (ZrO2) and distilled water. The mixture were heated at the various temperatures from 100 to 700 °C in the furnace with an incremental temperature of 100 °C. The ZrO2 contents in the composite ceramic were varied from 0 to 15 percent weight of CaO. The prepared composites were then annealed at 300, 600 and 700 °C for 4 h in air. The crystal structure, function group and morphology of all samples were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), field emission scanning electron microscopy (FESEM) and universal testing machine (UTM), respectively. The results indicated that the undoped-ZrO2 samples hydroxyapatite phase with a hexagonal structure. However, the hydroxyapatite was transformed to the tri-calcium phosphate after thermal treatment at 700 °C. For the doped-ZrO2 samples, the hydroxyapatite and ZrO2 phases were found. Moreover, the result showed that the compressive strength of hydroxyapatite-ZrO2 composite ceramic increased with increasing the ZrO2 content.

  10. Thermal effusivity measurement of conventional and organic coffee oils via photopyroelectric technique.

    Science.gov (United States)

    Bedoya, A; Gordillo-Delgado, F; Cruz-Santillana, Y E; Plazas, J; Marin, E

    2017-12-01

    In this work, oil samples extracted from organic and conventional coffee beans were studied. A fatty acids profile analysis was done using gas chromatography and physicochemical analysis of density and acidity index to verify the oil purity. Additionally, Mid-Infrared Fourier Transform Photoacoustic Spectroscopy (FTIR-PAS) aided by Principal Component Analysis (PCA) was used to identify differences between the intensities of the absorption bands related to functional groups. Thermal effusivity values between 592±3 and 610±4Ws 1/2 m -2 K -1 were measured using the photopyroelectric technique in a front detection configuration. The acidity index was between 1.11 and 1.27% and the density changed between 0.921 and 0.94g/mL. These variables, as well as the extraction yield between 12,6 and 14,4%, showed a similar behavior than that observed for the thermal effusivity, demonstrating that this parameter can be used as a criterion for discrimination between oil samples extracted from organic and conventional coffee beans. Copyright © 2017 Elsevier Ltd. All rights reserved.

  11. Ventilation and filtration techniques for handling aerosols produced by thermal cutting operations

    International Nuclear Information System (INIS)

    Bishop, A.

    1989-01-01

    This report describes the work done to characterize aerosols from thermal cutting operations and to develop suitable ventilation and filtration techniques. The work has been carried out under a research contract between the Windscale Laboratory and the Commission of the European Communities. The contract started in October 1984 and was completed in June 1988. The total cost of the work was UKL 132 000 of which 50% was funded by the Commission. This report has been compiled from the several progress reports submitted during the work period and details the main findings from the work programme. By working with colleagues from Commissariat a l'energie atomique, Saclay, France, additional useful data were collected. The bimodal size distribution of aerosols from oxypropane cutting was confirmed. Trials on various prefilters showed that the electrostatic precipitator (ESP) and the cartridge filter had excellent collection properties. From these trials the ESP was selected as the prefilter for the windscale advanced gas-cooled reactor (WAGR) decommissioning project. This work is presented in Appendix 1 to this report. Details are given of the proposals to modify the ESP to enable the safe removal of radioactive dust and contamined collector plates. Tests are described on aerosols generated by laser cutting and also trials on the ESP and high gradient magnetic separation prefilters. Finally, the measurement of filter burdens, aerosol concentrations and dust deposition rates from thermal cutting in a full-size ventilation rig are reported

  12. Application techniques of coatings by thermal projection; Tecnicas de aplicacion de recubrimientos por proyeccion termica

    Energy Technology Data Exchange (ETDEWEB)

    Porcayo Calderon, Jesus [Instituto de Investigaciones Electricas, Cuernavaca (Mexico)

    1995-12-31

    The coatings applied by thermal projection have an important number of applications in different industries (chemical, oil, electric, nuclear, etc.). The main purpose of the protection by means of coatings is to alter the surface characteristics of a component so as to resist corrosive environments, abrasion and erosion, among others. The coatings can be applied by different methods, but due to the fact that its characteristics appreciably differ from the base metal, it is important the knowledge of its properties when a coating is selected for a specific use. In this article the characteristics of the applied coatings by thermal projection, the factors that affect its performance and the principal application techniques, are described. [Espanol] Los recubrimientos aplicados por proyeccion termica tienen un numero importante de aplicaciones en diferentes industrias (quimica, petrolera, electrica, nuclear, etc.). El proposito principal de la proteccion por medio de recubrimientos es alterar las caracteristicas de la superficie de un componente de manera que resista ambientes corrosivos, abrasion y erosion, entre otros. Los recubrimientos pueden aplicarse por diferentes metodos, pero debido a que sus propiedades difieren apreciablemente de las del metal base, es importante el conocimiento de sus propiedades cuando se selecciona un recubrimiento para un uso especifico. En este articulo se describen las caracteristicas de los recubrimientos aplicados por proyeccion termica, los factores que afectan su desempeno y las principales tecnicas de aplicacion.

  13. Application techniques of coatings by thermal projection; Tecnicas de aplicacion de recubrimientos por proyeccion termica

    Energy Technology Data Exchange (ETDEWEB)

    Porcayo Calderon, Jesus [Instituto de Investigaciones Electricas, Cuernavaca (Mexico)

    1996-12-31

    The coatings applied by thermal projection have an important number of applications in different industries (chemical, oil, electric, nuclear, etc.). The main purpose of the protection by means of coatings is to alter the surface characteristics of a component so as to resist corrosive environments, abrasion and erosion, among others. The coatings can be applied by different methods, but due to the fact that its characteristics appreciably differ from the base metal, it is important the knowledge of its properties when a coating is selected for a specific use. In this article the characteristics of the applied coatings by thermal projection, the factors that affect its performance and the principal application techniques, are described. [Espanol] Los recubrimientos aplicados por proyeccion termica tienen un numero importante de aplicaciones en diferentes industrias (quimica, petrolera, electrica, nuclear, etc.). El proposito principal de la proteccion por medio de recubrimientos es alterar las caracteristicas de la superficie de un componente de manera que resista ambientes corrosivos, abrasion y erosion, entre otros. Los recubrimientos pueden aplicarse por diferentes metodos, pero debido a que sus propiedades difieren apreciablemente de las del metal base, es importante el conocimiento de sus propiedades cuando se selecciona un recubrimiento para un uso especifico. En este articulo se describen las caracteristicas de los recubrimientos aplicados por proyeccion termica, los factores que afectan su desempeno y las principales tecnicas de aplicacion.

  14. Single-molecule detection of dihydroazulene photo-thermal reaction using break junction technique

    Science.gov (United States)

    Huang, Cancan; Jevric, Martyn; Borges, Anders; Olsen, Stine T.; Hamill, Joseph M.; Zheng, Jue-Ting; Yang, Yang; Rudnev, Alexander; Baghernejad, Masoud; Broekmann, Peter; Petersen, Anne Ugleholdt; Wandlowski, Thomas; Mikkelsen, Kurt V.; Solomon, Gemma C.; Brøndsted Nielsen, Mogens; Hong, Wenjing

    2017-05-01

    Charge transport by tunnelling is one of the most ubiquitous elementary processes in nature. Small structural changes in a molecular junction can lead to significant difference in the single-molecule electronic properties, offering a tremendous opportunity to examine a reaction on the single-molecule scale by monitoring the conductance changes. Here, we explore the potential of the single-molecule break junction technique in the detection of photo-thermal reaction processes of a photochromic dihydroazulene/vinylheptafulvene system. Statistical analysis of the break junction experiments provides a quantitative approach for probing the reaction kinetics and reversibility, including the occurrence of isomerization during the reaction. The product ratios observed when switching the system in the junction does not follow those observed in solution studies (both experiment and theory), suggesting that the junction environment was perturbing the process significantly. This study opens the possibility of using nano-structured environments like molecular junctions to tailor product ratios in chemical reactions.

  15. Uncapped silver nanoparticles synthesized by DC arc thermal plasma technique for conductor paste formulation

    Science.gov (United States)

    Shinde, Manish; Pawar, Amol; Karmakar, Soumen; Seth, Tanay; Raut, Varsha; Rane, Sunit; Bhoraskar, Sudha; Amalnerkar, Dinesh

    2009-11-01

    Uncapped silver nanoparticles were synthesized by DC arc thermal plasma technique. The synthesized nanoparticles were structurally cubic and showed wide particle size variation (between 20-150 nm). Thick film paste formulated from such uncapped silver nanoparticles was screen-printed on alumina substrates and the resultant `green' films were fired at different firing temperatures. The films fired at 600 °C revealed better microstructure properties and also yielded the lowest value of sheet resistance in comparison to those corresponding to conventional peak firing temperature of 850 °C. Our findings directly support the role of silver nanoparticles in substantially depressing the operative peak firing temperature involved in traditional conductor thick films technology.

  16. Detection of coffee flavour ageing by solid-phase microextraction/surface acoustic wave sensor array technique (SPME/SAW).

    Science.gov (United States)

    Barié, Nicole; Bücking, Mark; Stahl, Ullrich; Rapp, Michael

    2015-06-01

    The use of polymer coated surface acoustic wave (SAW) sensor arrays is a very promising technique for highly sensitive and selective detection of volatile organic compounds (VOCs). We present new developments to achieve a low cost sensor setup with a sampling method enabling the highly reproducible detection of volatiles even in the ppb range. Since the VOCs of coffee are well known by gas chromatography (GC) research studies, the new sensor array was tested for an easy assessable objective: coffee ageing during storage. As reference method these changes were traced with a standard GC/FID set-up, accompanied by sensory panellists. The evaluation of GC data showed a non-linear characteristic for single compound concentrations as well as for total peak area values, disabling prediction of the coffee age. In contrast, the new SAW sensor array demonstrates a linear dependency, i.e. being capable to show a dependency between volatile concentration and storage time. Copyright © 2014 Elsevier Ltd. All rights reserved.

  17. Sensors Based Measurement Techniques of Fuel Injection and Ignition Characteristics of Diesel Sprays in DI Combustion System

    Directory of Open Access Journals (Sweden)

    S. Rehman

    2016-09-01

    Full Text Available Innovative sensor based measurement techniques like needle lift sensor, photo (optical sensor and piezoresistive pressure transmitter are introduced and used to measure the injection and combustion characteristics in direct injection combustion system. Present experimental study is carried out in the constant volume combustion chamber to study the ignition, combustion and injection characteristics of the solid cone diesel fuel sprays impinging on the hot surface. Hot surface ignition approach has been used to create variety of advanced combustion systems. In the present study, the hot surface temperatures were varied from 623 K to 723 K. The cylinder air pressures were 20, 30 and 40 bar and fuel injection pressures were 100, 200 and 300 bar. It is found that ignition delay of fuel sprays get reduced with the rise in injection pressure. The ignition characteristics of sprays much less affected at high fuel injection pressures and high surface temperatures. The fuel injection duration reduces with the increase in fuel injection pressures. The rate of heat release becomes high at high injection pressures and it decreases with the increase in injection duration. It is found that duration of burn/combustion decrease with the increase in injection pressure. The use of various sensors is quite effective, reliable and accurate in measuring the various fuel injection and combustion characteristics. The study simulates the effect of fuel injection system parameters on combustion performance in large heavy duty engines.

  18. FEASIBILITY STUDY OF INEXPENSIVE THERMAL SENSORS AND SMALL UAS DEPLOYMENT FOR LIVING HUMAN DETECTION IN RESCUE MISSIONS APPLICATION SCENARIOS

    Directory of Open Access Journals (Sweden)

    E. Levin

    2016-06-01

    Full Text Available Significant efforts are invested by rescue agencies worldwide to save human lives during natural and man-made emergency situations including those that happen in wilderness locations. These emergency situations include but not limited to: accidents with alpinists, mountainous skiers, people hiking and lost in remote areas. Sometimes in a rescue operation hundreds of first responders are involved to save a single human life. There are two critical issues where geospatial imaging can be a very useful asset in rescue operations support: 1 human detection and 2 confirming a fact that detected a human being is alive. International group of researchers from the Unites States and Poland collaborated on a pilot research project devoted to identify a feasibility of use for the human detection and alive-human state confirmation small unmanned aerial vehicles (SUAVs and inexpensive forward looking infrared (FLIR sensors. Equipment price for both research teams was below $8,000 including 3DR quadrotor UAV and Lepton longwave infrared (LWIR imager which costs around $250 (for the US team; DJI Inspire 1 UAS with commercial Tamarisc-320 thermal camera (for the Polish team. Specifically both collaborating groups performed independent experiments in the USA and Poland and shared imaging data of on the ground and airborne electro-optical and FLIR sensor imaging collected. In these experiments dead bodies were emulated by use of medical training dummies. Real humans were placed nearby as live human subjects. Electro-optical imagery was used for the research in optimal human detection algorithms. Furthermore, given the fact that a dead human body after several hours has a temperature of the surrounding environment our experiments were challenged by the SUAS data optimization, i.e., distance from SUAV to object so that the FLIR sensor is still capable to distinguish temperature differences between a dummy and a real human. Our experiments indicated feasibility of

  19. Experimental and mathematical simulation techniques for determining an in-situ response testing method for neutron sensors used in reactor power plant protection systems

    International Nuclear Information System (INIS)

    Behbahani, A.

    1983-01-01

    An analytical neutron sensor response model and methods for transient response measurements of neutron sensors (compensated ionization chamber), including possible in-situ techniques have been developed and evaluated to meet the provisions of Draft Standard ISA Sd67.06, IEEE 338-1977, and NRC Guide 1.118. One in-situ method requires the perturbation of the high voltage detector (sensor) power supply and measurement of the sensor response. The response to a perturbation of the power supply is related to the response of the sensor to a transient change in neutron flux. Random signal analysis is another in-situ technique to monitor the neutron sensor response. In this method the power spectrum of the inherent fluctuations from the neutron sensor output (current in CIC) are measured and evaluated. Transient response techniques (including in-situ methods) are experimentally and analytically evaluated to identify the mechanisms which may cause degradation in the response of the neutron sensors. The objective of the experimental evaluation was to correlate the measured response time using transient radiation flux changes and power supply perturbation. The objective of the analytical model of the different sensor response was to predict response time and degradation mechanisms

  20. Monitoring soil moisture patterns in alpine meadows using ground sensor networks and remote sensing techniques

    Science.gov (United States)

    Bertoldi, Giacomo; Brenner, Johannes; Notarnicola, Claudia; Greifeneder, Felix; Nicolini, Irene; Della Chiesa, Stefano; Niedrist, Georg; Tappeiner, Ulrike

    2015-04-01

    Soil moisture content (SMC) is a key factor for numerous processes, including runoff generation, groundwater recharge, evapotranspiration, soil respiration, and biological productivity. Understanding the controls on the spatial and temporal variability of SMC in mountain catchments is an essential step towards improving quantitative predictions of catchment hydrological processes and related ecosystem services. The interacting influences of precipitation, soil properties, vegetation, and topography on SMC and the influence of SMC patterns on runoff generation processes have been extensively investigated (Vereecken et al., 2014). However, in mountain areas, obtaining reliable SMC estimations is still challenging, because of the high variability in topography, soil and vegetation properties. In the last few years, there has been an increasing interest in the estimation of surface SMC at local scales. On the one hand, low cost wireless sensor networks provide high-resolution SMC time series. On the other hand, active remote sensing microwave techniques, such as Synthetic Aperture Radars (SARs), show promising results (Bertoldi et al. 2014). As these data provide continuous coverage of large spatial extents with high spatial resolution (10-20 m), they are particularly in demand for mountain areas. However, there are still limitations related to the fact that the SAR signal can penetrate only a few centimeters in the soil. Moreover, the signal is strongly influenced by vegetation, surface roughness and topography. In this contribution, we analyse the spatial and temporal dynamics of surface and root-zone SMC (2.5 - 5 - 25 cm depth) of alpine meadows and pastures in the Long Term Ecological Research (LTER) Area Mazia Valley (South Tyrol - Italy) with different techniques: (I) a network of 18 stations; (II) field campaigns with mobile ground sensors; (III) 20-m resolution RADARSAT2 SAR images; (IV) numerical simulations using the GEOtop hydrological model (Rigon et al

  1. The development of fusion sensor techniques for condition monitoring of a check valve

    International Nuclear Information System (INIS)

    Seong, S.H.; Kim, J.S.; Hur, S.; Kim, J.T.; Park, W.M.; Cha, D.B.

    2004-01-01

    The failures of check valves are one of the most important problems in nuclear power plants because the reverse flows through the failed check valve impact on the healthy hydraulic loop. The present test method of finding out the mechanical failure of a check valve is very risky in the radiated environments during normal operation. In addition, the detection of failures in the overhaul period is very costly and tedious because many check valves are used in the plants and manual disassembly work is required. We have suggested the fusion sensor technology for detecting the failures of check valves through measuring and analyzing the backward leakage flow and mechanical vibration without disassembling the check valve. The fusion sensor means that more than two sensors are used in order to identify and analyze the changes of the frequency response between the failed check valve and healthy check valve. We use the accelerometer and acoustic emission sensor as an alternative to the fusion sensor methodology. We have found that the acoustic emission sensor would be capable of directly detecting a high frequency acoustic wave generated from backward leakage flow itself at a low pressure and temperature. The accelerometer for detecting the mechanical vibration induced from leakage flows would, also, be useful at a high pressure and temperature from the previous studies. The effectiveness of this system is that it is possible for predictive maintenance and information of the problem valve will be captured and it reduces the radiation exposure for the maintenance personnel during power operation as well as the maintenance period. (orig.)

  2. Designing a highly sensitive Eddy current sensor for evaluating damage on thermal barrier coating

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jong Min; Kim, Hak Joon; Song, Sung Jin; Seok, Chang Seong; Lee, Yeong Ze [Dept. of Mechanical Engineering, Sungkyunkwan University, Suwon (Korea, Republic of); Lee, Seul Gi [LG Electronics, Seoul (Korea, Republic of)

    2016-06-15

    A thermal barrier coating (TBC) has been widely applied to machine components working under high temperature as a thermal insulator owing to its critical financial and safety benefits to the industry. However, the nondestructive evaluation of TBC damage is not easy since sensing of the microscopic change that occurs on the TBC is required during an evaluation. We designed an eddy current probe for evaluating damage on a TBC based on the finite element method (FEM) and validated its performance through an experiment. An FEM analysis predicted the sensitivity of the probe, showing that impedance change increases as the TBC thermally degrades. In addition, the effect of the magnetic shield concentrating magnetic flux density was also observed. Finally, experimental validation showed good agreement with the simulation result.

  3. Refractometric sensitivity and thermal stabilization of fluorescent core microcapillary sensors: theory and experiment.

    Science.gov (United States)

    Lane, S; Marsiglio, F; Zhi, Y; Meldrum, A

    2015-02-20

    Fluorescent-core microcapillaries (FCMs) present a robust basis for the application of optical whispering gallery modes toward refractometric sensing. An important question concerns whether these devices can be rendered insensitive to local temperature fluctuations, which may otherwise limit their refractometric detection limits, mainly as a result of thermorefractive effects. Here, we first use a standard cylindrical cavity formalism to develop the refractometric and thermally limited detection limits for the FCM structure. We then measure the thermal response of a real device with different analytes in the channel and compare the result to the theory. Good stability against temperature fluctuations was obtained for an ethanol solvent, with a near-zero observed thermal shift for the transverse magnetic modes. Similarly good results could in principle be obtained for any other solvent (e.g., water), if the thickness of the fluorescent layer can be sufficiently well controlled.

  4. A Low Power 2.4 GHz CMOS Mixer Using Forward Body Bias Technique for Wireless Sensor Network

    Science.gov (United States)

    Yin, C. J.; Murad, S. A. Z.; Harun, A.; Ramli, M. M.; Zulkifli, T. Z. A.; Karim, J.

    2018-03-01

    Wireless sensor network (WSN) is a highly-demanded application since the evolution of wireless generation which is often used in recent communication technology. A radio frequency (RF) transceiver in WSN should have a low power consumption to support long operating times of mobile devices. A down-conversion mixer is responsible for frequency translation in a receiver. By operating a down-conversion mixer at a low supply voltage, the power consumed by WSN receiver can be greatly reduced. This paper presents a development of low power CMOS mixer using forward body bias technique for wireless sensor network. The proposed mixer is implemented using CMOS 0.13 μm Silterra technology. The forward body bias technique is adopted to obtain low power consumption. The simulation results indicate that a low power consumption of 0.91 mW is achieved at 1.6 V supply voltage. Moreover, the conversion gain (CG) of 21.83 dB, the noise figure (NF) of 16.51 dB and the input-referred third-order intercept point (IIP3) of 8.0 dB at 2.4 GHz are obtained. The proposed mixer is suitable for wireless sensor network.

  5. Neutron spectral modulation as a new thermal neutron scattering technique. Pt. 1

    International Nuclear Information System (INIS)

    Ito, Y.; Nishi, M.; Motoya, K.

    1982-01-01

    A thermal neutron scattering technique is presented based on a new idea of labelling each neutron in its spectral position as well as in time through the scattering process. The method makes possible the simultaneous determination of both the accurate dispersion relation and its broadening by utilizing the resolution cancellation property of zero-crossing points in the cross-correlated time spectrum together with the Fourier transform scheme of the neutron spin echo without resorting to the echoing. The channel Fourier transform applied to the present method also makes possible the determination of the accurate direct energy scan profile of the scattering function with a rather broad incident neutron wavelength distribution. Therefore the intensity sacrifice for attaining high accurarcy is minimized. The technique is used with either a polarized or unpolarized beam at the sample position with no precautions against beam depolarization at the sample for the latter case. Relative time accurarcy of the order of 10 -3 to 10 -4 may be obtained for the general dispersion relation and for the quasi-elastic energy transfers using correspondingly the relative incident neutron wavelength spread of 10 to 1% around an incident neutron energy of a few meV. (orig.)

  6. Study of different biocomposite coatings on Ti alloy by a subsonic thermal spraying technique

    Energy Technology Data Exchange (ETDEWEB)

    Li Muqin [Provincial Key Laboratory of Biomaterials, Jiamusi University, Heilongjiang Province, 154007 (China); Zhang Rui [College of Stomatology, Jiamusi University, Heilongjiang Province, 154003 (China); Wang Jianping [College of Stomatology, Jiamusi University, Heilongjiang Province, 154003 (China); Yang Shiqin [State Key Laboratory Advanced Welding Production Technology, Harbin Institute of Technology, 150001 (China)

    2007-03-01

    A subsonic thermal spraying technique (STS) was used to make different biocomposite coatings on titanium alloys for preparing three kinds of implants: 8Ti2G, HA and 8H2B, respectively. The implants were embedded in a region of jaw of dogs whose teeth were pulled out three months previously. The dogs, in two groups, were killed 30 days and 90 days, respectively, after they were operated on. Osteointegration between the implants and host bone was investigated by x-ray, histology and the SEM technique. The results showed that the three kinds of coatings all exhibited good biocompatibility and synostosis, but their osteointegration capability showed a difference and decreased in the sequence of 8H2B, HA and 8Ti2G. The activity of coating, which promoted the reactions between implants and bone tissue, was further increased by the addition of bioglass in the 8H2B coating. Subsequently, chemical bonding was formed, and the osteointegration strength was increased. The study provided a new approach to prepare biocomposite coatings. The 8H2B implants, which formed an integral functional biocomposite coating on Ti alloys, showed a better osteointegration capability with bioactivity and pore gradient variation. A theoretical base was provided for the biocomposite coating application.

  7. An explanation for anomalous thermal conductivity behaviour in nanofluids as measured using the hot-wire technique

    International Nuclear Information System (INIS)

    Marín, E; Bedoya, A; Alvarado, S; Calderón, A; Ivanov, R; Gordillo-Delgado, F

    2014-01-01

    Several efforts have been made to explain thermal conductivity enhancements in fluids due to the addition of nanoparticles. However, until now, there has been no general consensus on this issue. In this work a simple experiment is described that demonstrates a possible cause of misinterpretation of the experimental data of thermal conductivity obtained when using the hot-wire technique (HWT) in these systems. It has been demonstrated that the thermal conductivity of a two-layer sample of two non-miscible phase systems determined by means of the HWT must be modelled using a series thermal resistance model with consideration of the interfacial layers between different phases. This result sheds light on the thermal conductivity enhancement in nanofluids with respect to the values corresponding to the base fluid, suggesting that this increase can be explained using the above-mentioned model and not by application of empirical formulae for effective media, as done before. (paper)

  8. A correction scheme for thermal conductivity measurement using the comparative cut-bar technique based on 3D numerical simulation

    International Nuclear Information System (INIS)

    Xing, Changhu; Folsom, Charles; Jensen, Colby; Ban, Heng; Marshall, Douglas W

    2014-01-01

    As an important factor affecting the accuracy of thermal conductivity measurement, systematic (bias) error in the guarded comparative axial heat flow (cut-bar) method was mostly neglected by previous researches. This bias is primarily due to the thermal conductivity mismatch between sample and meter bars (reference), which is common for a sample of unknown thermal conductivity. A correction scheme, based on finite element simulation of the measurement system, was proposed to reduce the magnitude of the overall measurement uncertainty. This scheme was experimentally validated by applying corrections on four types of sample measurements in which the specimen thermal conductivity is much smaller, slightly smaller, equal and much larger than that of the meter bar. As an alternative to the optimum guarding technique proposed before, the correction scheme can be used to minimize the uncertainty contribution from the measurement system with non-optimal guarding conditions. It is especially necessary for large thermal conductivity mismatches between sample and meter bars. (paper)

  9. The thermal stability of the carbon-palladium films for hydrogen sensor applications

    Science.gov (United States)

    Rymarczyk, Joanna; Czerwosz, ElŻbieta; Diduszko, Ryszard; Kozłowski, Mirosław

    2017-08-01

    The thermal stability of two types of C-Pd films prepared in PVD process were studied. These films are composed of Pd nanograins embedded in a multiphase carbonaceous matrix. These films were distinguished by Pd content. These films were annealed in a range of temperatures 50÷1000°C. The structural, topographical and molecular changes were studied by scanning electron microscopy (SEM), infrared spectroscopy (FTIR) and X-ray diffraction (XRD) methods. The results show that investigated films are thermally stable up to 200°C.

  10. Study of thermal pressure and phase transitions in H2O using optical pressure sensors in the diamond anvil cell

    International Nuclear Information System (INIS)

    Sundberg, Sara; Lazor, Peter

    2004-01-01

    We present results of a study on the phase equilibria and pressure-volume-temperature relations for water and ice VII using an optical system designed for Raman spectroscopy and pressure-temperature measurements. The study shows that the strontium borate sensor represents an important tool for high-pressure-high-temperature manometry for temperatures below 600 K. In the pressure-temperature ranges 0-5 GPa and 240-600 K we detected phase transformations between four phases of H 2 O as documented by Raman spectra, pressure-temperature scans, and visual observations. Analysis of the interference fringes and comparison of the experimental data on thermal pressure with the published equations of state (EOSs) show that the heating/cooling cycles were carried out under quasi-isochoric conditions. The experimental results are discussed/analysed on the basis of different EOSs for water and ice

  11. Fiber-optic combined FPI/FBG sensors for monitoring of radiofrequency thermal ablation of liver tumors: ex vivo experiments.

    Science.gov (United States)

    Tosi, Daniele; Macchi, Edoardo Gino; Braschi, Giovanni; Cigada, Alfredo; Gallati, Mario; Rossi, Sandro; Poeggel, Sven; Leen, Gabriel; Lewis, Elfed

    2014-04-01

    We present a biocompatible, all-glass, 0.2 mm diameter, fiber-optic probe that combines an extrinsic Fabry-Perot interferometry and a proximal fiber Bragg grating sensor; the probe enables dual pressure and temperature measurement on an active 4 mm length, with 40 Pa and 0.2°C nominal accuracy. The sensing system has been applied to monitor online the radiofrequency thermal ablation of tumors in liver tissue. Preliminary experiments have been performed in a reference chamber with uniform heating; further experiments have been carried out on ex vivo porcine liver, which allowed the measurement of a steep temperature gradient and monitoring of the local pressure increase during the ablation procedure.

  12. Materials and Techniques for Implantable Nutrient Sensing Using Flexible Sensors Integrated with Metal-Organic Frameworks.

    Science.gov (United States)

    Ling, Wei; Liew, Guoguang; Li, Ya; Hao, Yafeng; Pan, Huizhuo; Wang, Hanjie; Ning, Baoan; Xu, Hang; Huang, Xian

    2018-06-01

    The combination of novel materials with flexible electronic technology may yield new concepts of flexible electronic devices that effectively detect various biological chemicals to facilitate understanding of biological processes and conduct health monitoring. This paper demonstrates single- or multichannel implantable flexible sensors that are surface modified with conductive metal-organic frameworks (MOFs) such as copper-MOF and cobalt-MOF with large surface area, high porosity, and tunable catalysis capability. The sensors can monitor important nutriments such as ascorbicacid, glycine, l-tryptophan (l-Trp), and glucose with detection resolutions of 14.97, 0.71, 4.14, and 54.60 × 10 -6 m, respectively. In addition, they offer sensing capability even under extreme deformation and complex surrounding environment with continuous monitoring capability for 20 d due to minimized use of biological active chemicals. Experiments using live cells and animals indicate that the MOF-modified sensors are biologically safe to cells, and can detect l-Trp in blood and interstitial fluid. This work represents the first effort in integrating MOFs with flexible sensors to achieve highly specific and sensitive implantable electrochemical detection and may inspire appearance of more flexible electronic devices with enhanced capability in sensing, energy storage, and catalysis using various properties of MOFs. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Development of a Sensor-Based Structural Integrity Measurement Technique for Potential Application to Missile Casings

    National Research Council Canada - National Science Library

    Triplett, M; Kess, H. R; Sundararaman, S; Shah, C. D; Adams, D. E; Walsh, S. M; Pergantis, C. G

    2006-01-01

    .... It is one of the first known efforts to integrate sensor data with structural analytic and numerical models to provide not only a location and history of adverse loading events, but also an estimate of stiffness degradation in the structural casing. S2 glass/epoxy composite cylinders were chosen because they provide an observable means of witnessing damage for correlation purposes.

  14. Visualization and Analysis of Wireless Sensor Network Data for Smart Civil Structure Applications Based On Spatial Correlation Technique

    Science.gov (United States)

    Chowdhry, Bhawani Shankar; White, Neil M.; Jeswani, Jai Kumar; Dayo, Khalil; Rathi, Manorma

    2009-07-01

    Disasters affecting infrastructure, such as the 2001 earthquakes in India, 2005 in Pakistan, 2008 in China and the 2004 tsunami in Asia, provide a common need for intelligent buildings and smart civil structures. Now, imagine massive reductions in time to get the infrastructure working again, realtime information on damage to buildings, massive reductions in cost and time to certify that structures are undamaged and can still be operated, reductions in the number of structures to be rebuilt (if they are known not to be damaged). Achieving these ideas would lead to huge, quantifiable, long-term savings to government and industry. Wireless sensor networks (WSNs) can be deployed in buildings to make any civil structure both smart and intelligent. WSNs have recently gained much attention in both public and research communities because they are expected to bring a new paradigm to the interaction between humans, environment, and machines. This paper presents the deployment of WSN nodes in the Top Quality Centralized Instrumentation Centre (TQCIC). We created an ad hoc networking application to collect real-time data sensed from the nodes that were randomly distributed throughout the building. If the sensors are relocated, then the application automatically reconfigures itself in the light of the new routing topology. WSNs are event-based systems that rely on the collective effort of several micro-sensor nodes, which are continuously observing a physical phenomenon. WSN applications require spatially dense sensor deployment in order to achieve satisfactory coverage. The degree of spatial correlation increases with the decreasing inter-node separation. Energy consumption is reduced dramatically by having only those sensor nodes with unique readings transmit their data. We report on an algorithm based on a spatial correlation technique that assures high QoS (in terms of SNR) of the network as well as proper utilization of energy, by suppressing redundant data transmission

  15. Analytical techniques for determination and control of silica content in the water in thermal power plants

    Directory of Open Access Journals (Sweden)

    Ignjatović Nataša R.

    2015-01-01

    Full Text Available Ultrapure water with minimum contents of impurities is used for the preparation of steam in thermal power plants. More recently it has been found that the corrosion process is also influenced by sodium ions, chloride ions, and all forms of silicon in water. At higher temperatures and under high pressure the less soluble compounds of silicon are extracted, which form deposits on the walls of the boiler, the piping system and the turbine blades. Silicon is found in water in the form of different types (species which are characterized by specific physical and chemical properties. Distinctions can be made between highly reactive species of ionic (silicate anions and molecular forms (silicic acid and relatively inert types (suspended, colloidal, and polymerized silicon. The determination of various forms of silicon in water is a complex analytical task. This paper covers relevant research in the field of silicon specification analysis. Maintaining the unchanged, original composition of silicon species during various stages of analysis (sample collection, storage, and conservation has been given special attention. A large number of methods and procedures have been developed for the analysis of species of silicon, including chromatographic, spectroscopic and electrochemical techniques and combinations thereof. The techniques used for determining both the total amount and individual forms of silicon have been singled out. There is also an overview of the coupled techniques used most frequently in practice by using the methodology which involves preliminary separation of species and then individual specification. The paper offers an overview of analytical properties, advantages and disadvantages of the most representative analytical methods developed specifically for the analysis of silicon species in ultrapure water. The most important studies focusing on the silicon species in water have been highlighted and presented in detail. The determination of

  16. A Novel Microdialysis Glucose Sensor System Based on Co-immobilizing on AU Micro-Electrode by SOL-GEL Technique

    National Research Council Canada - National Science Library

    Yu, Ping

    2001-01-01

    .... The sensor is based on co_immobilizing glucose oxidase (COD) with the catalase by sol-gel technique on the surface of the silicon bases with two pattern of An microelectrodes. A graduated ("sandwich...

  17. Influence of an absorbers GEMPEHD thermal properties on the propagation of heat in a solar sensor

    Directory of Open Access Journals (Sweden)

    Nassim Baba Ahmed

    2018-01-01

    Full Text Available This paper presents an experimental study to measure some physic-chemical properties of a high-density polyethylene geomembane (GEMPEHD in a temperature range from 300 K to 400 K. The results will yield a dependency between temperature and its properties in order to study an energy and process the thermal aging GEMPEHD on the solar collector. In the energy study, we solve the nonlinear equation of unsteady heat with as main non linearity influence of different properties GEMPEHD on the solar collector and one notes that the GEMPEHD presented a maximum exchange Thermal characterized by high absorption and low reflection. Thus, increasing the power absorbed by the GEMPEHD increases its temperature and the useful power received by the air and then the air temperature. Overall losses increase with the increase of the temperature difference between the GEMPEHD and windows and this increases the efficiency of the solar collector and minimize the entropy of the system. Then the study of thermal aging is dedicated to the interpretation of various analyses on GEMPEHD before and after its use in the solar collector. The thermal aging GEMPEHD in the air is a physical loss and chemical consumption immediately followed by a brutal oxidation of the polymer. The losses would be governed primarily by the chemical consumption of antioxidants. After various tests, we conclude that the value of using the GEMPEHD as absorber in the solar collector is doubly beneficial. First, given its very attractive cost compared to other as efficient absorbers (such as metals gives good thermal performance of the solar collector even reaching 72%. While the life of the GEMPEHD is rather long (several years.

  18. Fiber-Optic Temperature and Pressure Sensors Applied to Radiofrequency Thermal Ablation in Liver Phantom: Methodology and Experimental Measurements

    Directory of Open Access Journals (Sweden)

    Daniele Tosi

    2015-01-01

    Full Text Available Radiofrequency thermal ablation (RFA is a procedure aimed at interventional cancer care and is applied to the treatment of small- and midsize tumors in lung, kidney, liver, and other tissues. RFA generates a selective high-temperature field in the tissue; temperature values and their persistency are directly related to the mortality rate of tumor cells. Temperature measurement in up to 3–5 points, using electrical thermocouples, belongs to the present clinical practice of RFA and is the foundation of a physical model of the ablation process. Fiber-optic sensors allow extending the detection of biophysical parameters to a vast plurality of sensing points, using miniature and noninvasive technologies that do not alter the RFA pattern. This work addresses the methodology for optical measurement of temperature distribution and pressure using four different fiber-optic technologies: fiber Bragg gratings (FBGs, linearly chirped FBGs (LCFBGs, Rayleigh scattering-based distributed temperature system (DTS, and extrinsic Fabry-Perot interferometry (EFPI. For each instrument, methodology for ex vivo sensing, as well as experimental results, is reported, leading to the application of fiber-optic technologies in vivo. The possibility of using a fiber-optic sensor network, in conjunction with a suitable ablation device, can enable smart ablation procedure whereas ablation parameters are dynamically changed.

  19. Design Optimization of Liquid Fueled High Velocity Oxy- Fuel Thermal Spraying Technique for Durable Coating for Fossil Power Systems

    Energy Technology Data Exchange (ETDEWEB)

    Choudhuri, Ahsan [Univ. of Texas, El Paso, TX (United States); Love, Norman [Univ. of Texas, El Paso, TX (United States)

    2016-11-04

    High-velocity oxy–fuel (HVOF) thermal spraying was developed in 1930 and has been commercially available for twenty-five years. HVOF thermal spraying has several benefits over the more conventional plasma spray technique including a faster deposition rate which leads to quicker turn-around, with more durable coatings and higher bond strength, hardness and wear resistance due to a homogeneous distribution of the sprayed particles. HVOF thermal spraying is frequently used in engineering to deposit cermets, metallic alloys, composites and polymers, to enhance product life and performance. HVOF thermal spraying system is a highly promising technique for applying durable coatings on structural materials for corrosive and high temperature environments in advanced ultra-supercritical coal- fired (AUSC) boilers, steam turbines and gas turbines. HVOF thermal spraying is the preferred method for producing coatings with low porosity and high adhesion. HVOF thermal spray process has been shown to be one of the most efficient techniques to deposit high performance coatings at moderate cost. Variables affecting the deposit formation and coating properties include hardware characteristics such as nozzle geometry and spraying distance and process parameters such as equivalence ratio, gas flow density, and powder feedstock. In the spray process, the powder particles experience very high speeds combined with fast heating to the powder material melting point or above. This high temperature causes evaporation of the powder, dissolution, and phase transformations. Due to the complex nature of the HVOF technique, the control and optimization of the process is difficult. In general, good coating quality with suitable properties and required performance for specific applications is the goal in producing thermal spray coatings. In order to reach this goal, a deeper understanding of the spray process as a whole is needed. Although many researchers studied commercial HVOF thermal spray

  20. Development of a technique for level measurement in pressure vessels using thermal probes and artificial neural networks

    International Nuclear Information System (INIS)

    Torres, Walmir Maximo

    2008-01-01

    A technique for level measurement in pressure vessels was developed using thermal probes with internal cooling and artificial neural networks (ANN's). This new concept of thermal probes was experimentally tested in an experimental facility (BETSNI) with two test sections, ST1 and ST2. Two different thermal probes were designed and constructed: concentric tubes probe and U tube probe. A data acquisition system (DAS) was assembled to record the experimental data during the tests. Steady state and transient level tests were carried out and the experimental data obtained were used as learning and recall data sets in the ANN's program RETRO-05 that simulate a multilayer perceptron with backpropagation. The results of the analysis show that the technique can be applied for level measurements in pressure vessel. The technique is applied for a less input temperature data than the initially designed to the probes. The technique is robust and can be used in case of lack of some temperature data. Experimental data available in literature from electrically heated thermal probe were also used in the ANN's analysis producing good results. The results of the ANN's analysis show that the technique can be improved and applied to level measurements in pressure vessels. (author)

  1. Development and characterization of thermal responsivehydrogel films for biomedical sensor application

    Science.gov (United States)

    López-Barriguete, Jesús Eduardo; Isoshima, Takashi; Bucio, Emilio

    2018-04-01

    Two flexible stimuli-responsive hydrogel films were elaborated as biomedical sensor application. The hydrogel systems were contained in glass moulds and synthesized using gamma radiation at a dose rate of 10.1 kGy h‑1, and absorbed dose of 50 kGy. The poly(NIPAAm) with a low critical solution temperature (LCST) close to the human body temperature, was employed as the principal component for the responsive materials. The addition of dimethyl acrylamide (DMAAm) for hydrophilic effect, methyl methacrylate (MMA) for mechanical property, and ethoxyethyl methacrylate (EEM) for mechanical property, modified the thermo dynamic transition point, obtaining viable responsive films with LCST of 36 °C and 39 °C. The samples were characterized by DSC to analyse the LCST, FT-IR to characterize the functional groups of the resulting films, AFM to examine the surface morphology, and swelling measurement to support the flexibility. Responsive ‘intelligent’ films with thermo sensitivity, biocompatibility, resistance, and conformableness are important to the development of flexible polymers for the application of biological sensor, smart membranes, or flexible electronics.

  2. Characterization of polymer-type ionic conductors using nuclear magnetic resonance and thermal analysis. Humidity sensor

    International Nuclear Information System (INIS)

    Cavalcante, Maria Goretti.

    1992-04-01

    We report a study using Nuclear Magnetic Resonance (NMR), Thermogravimetry Analysis, Differential Scanning Calorimetry and Infrared Spectroscopy in polymeric complexes formed poly(ethylene oxide), (PEO), and lithium salts. These complexes have have shown a large potential for technological applications in batteries, sensors, etc. We developed and characterized humidity sensors and discussed how the humidity affects the conformation of the complexes, the mobility of ionic species, and the polymeric chains. The results indicate that the hydration affects the conformation of polymeric complexes by plasticizing the water, which induces a volumetric expansion in the PEO chain. The processes was completely reversible for the level of hydration studied. NMR was used to distinguish the movement of polymeric chains from the movement of the ionic species. From the analysis of the second moment of resonance lines from the study of the nuclear relaxation we were able to estimate the average distance between the ionic species and the proton in the complexes chains. The behaviour of spin -lattice relaxation of hydrogen and fluorine in the P(EO) - Li B F, as a function of temperature and frequency reflects the nature of the disorder and the complexity of the ionic conduction process in these materials. (author). 91 refs., 69 figs., 2 tabs

  3. Thermal Transmission through Existing Building Enclosures: Destructive Monitoring in Intermediate Layers versus Non-Destructive Monitoring with Sensors on Surfaces

    Science.gov (United States)

    Echarri, Víctor; Espinosa, Almudena; Rizo, Carlos

    2017-01-01

    Opaque enclosures of buildings play an essential role in the level of comfort experienced indoors and annual energy demand. The impact of solar radiation and thermal inertia of the materials that make up the multi-layer enclosures substantially modify thermal transmittance behaviour of the enclosures. This dynamic form of heat transfer, additionally affected by indoor HVAC systems, has a substantial effect on the parameters that define comfort. It also has an impact on energy demand within a daily cycle as well as throughout a one-year use cycle. This study describes the destructive monitoring of an existing block of flats located in Alicante. Once the enclosure was opened, sensors of temperature (PT100), air velocity, and relative humidity were located in the different layers of the enclosure, as well as in the interior and exterior surfaces. A pyranometer was also installed to measure solar radiation levels. A temperature data correction algorithm was drawn up to address irregularities produced in the enclosure. The algorithm was applied using a Raspberry Pi processor in the data collection system. The comparative results of temperature gradients versus non-destructive monitoring systems are presented, providing measures of the transmittance value, surface temperatures and indoor and outdoor air temperatures. This remote sensing system can be used in future studies to quantify and compare the energy savings of different enclosure construction solutions. PMID:29292781

  4. A thermal-driven silicon micro xy-stage integrated with piezoresistive sensors for nano-positioning

    International Nuclear Information System (INIS)

    Choi, Young-Soo; Zhang, Yan; Lee, Dong-Weon

    2012-01-01

    This paper describes a novel micro xy-stage, driven by double-hot arm horizontal thermal micro-actuators integrated with a piezoresistive sensor (PS) for low-voltage operation and precise control. This micro xy-stage structure is linked with chevron beams and optimized to amplify the displacement generated by the micro-actuators that provide a pull force to the movable platform. The PS employed for in situ displacement detection and feedback control is fabricated at the base of a cold arm, which minimizes the influence of temperature change induced by electro-thermal heating. The micro xy-stage structure is defined through the use of a simple micromachining process, released by backside wet etching with a special tool. For an input power of approximately 44 mW, each chevron actuator provides about 16 µm and the total displacement of the platform is close to 32 µm. The sensitivity of the PS is better than 1 mV µm −1 , obtained from the amplified voltage output of the Wheatstone bridge circuit. The potential applications of the proposed micro xy-stage lie in micro- or nano-manipulation, as well as the positioning of ultra-small objects in nanotechnology. (paper)

  5. Ultrasonic Sensor Signals and Optimum Path Forest Classifier for the Microstructural Characterization of Thermally-Aged Inconel 625 Alloy

    Directory of Open Access Journals (Sweden)

    Victor Hugo C. de Albuquerque

    2015-05-01

    Full Text Available Secondary phases, such as laves and carbides, are formed during the final solidification stages of nickel-based superalloy coatings deposited during the gas tungsten arc welding cold wire process. However, when aged at high temperatures, other phases can precipitate in the microstructure, like the γ'' and δ phases. This work presents an evaluation of the powerful optimum path forest (OPF classifier configured with six distance functions to classify background echo and backscattered ultrasonic signals from samples of the inconel 625 superalloy thermally aged at 650 and 950 \\(^\\circ\\C for 10, 100 and 200 h. The background echo and backscattered ultrasonic signals were acquired using transducers with frequencies of 4 and 5 MHz. The potentiality of ultrasonic sensor signals combined with the OPF to characterize the microstructures of an inconel 625 thermally aged and in the as-welded condition were confirmed by the results. The experimental results revealed that the OPF classifier is sufficiently fast (classification total time of 0.316 ms and accurate (accuracy of 88.75% and harmonic mean of 89.52 for the application proposed.

  6. Ultrasonic sensor signals and optimum path forest classifier for the microstructural characterization of thermally-aged inconel 625 alloy.

    Science.gov (United States)

    de Albuquerque, Victor Hugo C; Barbosa, Cleisson V; Silva, Cleiton C; Moura, Elineudo P; Filho, Pedro P Rebouças; Papa, João P; Tavares, João Manuel R S

    2015-05-27

    Secondary phases, such as laves and carbides, are formed during the final solidification stages of nickel-based superalloy coatings deposited during the gas tungsten arc welding cold wire process. However, when aged at high temperatures, other phases can precipitate in the microstructure, like the γ'' and δ phases. This work presents an evaluation of the powerful optimum path forest (OPF) classifier configured with six distance functions to classify background echo and backscattered ultrasonic signals from samples of the inconel 625 superalloy thermally aged at 650 and 950 °C for 10, 100 and 200 h. The background echo and backscattered ultrasonic signals were acquired using transducers with frequencies of 4 and 5 MHz. The potentiality of ultrasonic sensor signals combined with the OPF to characterize the microstructures of an inconel 625 thermally aged and in the as-welded condition were confirmed by the results. The experimental results revealed that the OPF classifier is sufficiently fast (classification total time of 0.316 ms) and accurate (accuracy of 88.75%" and harmonic mean of 89.52) for the application proposed.

  7. Thermal Transmission through Existing Building Enclosures: Destructive Monitoring in Intermediate Layers versus Non-Destructive Monitoring with Sensors on Surfaces.

    Science.gov (United States)

    Echarri, Víctor; Espinosa, Almudena; Rizo, Carlos

    2017-12-08

    Opaque enclosures of buildings play an essential role in the level of comfort experienced indoors and annual energy demand. The impact of solar radiation and thermal inertia of the materials that make up the multi-layer enclosures substantially modify thermal transmittance behaviour of the enclosures. This dynamic form of heat transfer, additionally affected by indoor HVAC systems, has a substantial effect on the parameters that define comfort. It also has an impact on energy demand within a daily cycle as well as throughout a one-year use cycle. This study describes the destructive monitoring of an existing block of flats located in Alicante. Once the enclosure was opened, sensors of temperature (PT100), air velocity, and relative humidity were located in the different layers of the enclosure, as well as in the interior and exterior surfaces. A pyranometer was also installed to measure solar radiation levels. A temperature data correction algorithm was drawn up to address irregularities produced in the enclosure. The algorithm was applied using a Raspberry Pi processor in the data collection system. The comparative results of temperature gradients versus non-destructive monitoring systems are presented, providing measures of the transmittance value, surface temperatures and indoor and outdoor air temperatures. This remote sensing system can be used in future studies to quantify and compare the energy savings of different enclosure construction solutions.

  8. Thermal Transmission through Existing Building Enclosures: Destructive Monitoring in Intermediate Layers versus Non-Destructive Monitoring with Sensors on Surfaces

    Directory of Open Access Journals (Sweden)

    Víctor Echarri

    2017-12-01

    Full Text Available Opaque enclosures of buildings play an essential role in the level of comfort experienced indoors and annual energy demand. The impact of solar radiation and thermal inertia of the materials that make up the multi-layer enclosures substantially modify thermal transmittance behaviour of the enclosures. This dynamic form of heat transfer, additionally affected by indoor HVAC systems, has a substantial effect on the parameters that define comfort. It also has an impact on energy demand within a daily cycle as well as throughout a one-year use cycle. This study describes the destructive monitoring of an existing block of flats located in Alicante. Once the enclosure was opened, sensors of temperature (PT100, air velocity, and relative humidity were located in the different layers of the enclosure, as well as in the interior and exterior surfaces. A pyranometer was also installed to measure solar radiation levels. A temperature data correction algorithm was drawn up to address irregularities produced in the enclosure. The algorithm was applied using a Raspberry Pi processor in the data collection system. The comparative results of temperature gradients versus non-destructive monitoring systems are presented, providing measures of the transmittance value, surface temperatures and indoor and outdoor air temperatures. This remote sensing system can be used in future studies to quantify and compare the energy savings of different enclosure construction solutions.

  9. Reusable bi-directional 3ω sensor to measure thermal conductivity of 100-μm thick biological tissues

    Science.gov (United States)

    Lubner, Sean D.; Choi, Jeunghwan; Wehmeyer, Geoff; Waag, Bastian; Mishra, Vivek; Natesan, Harishankar; Bischof, John C.; Dames, Chris

    2015-01-01

    Accurate knowledge of the thermal conductivity (k) of biological tissues is important for cryopreservation, thermal ablation, and cryosurgery. Here, we adapt the 3ω method—widely used for rigid, inorganic solids—as a reusable sensor to measure k of soft biological samples two orders of magnitude thinner than conventional tissue characterization methods. Analytical and numerical studies quantify the error of the commonly used "boundary mismatch approximation" of the bi-directional 3ω geometry, confirm that the generalized slope method is exact in the low-frequency limit, and bound its error for finite frequencies. The bi-directional 3ω measurement device is validated using control experiments to within ±2% (liquid water, standard deviation) and ±5% (ice). Measurements of mouse liver cover a temperature ranging from -69 °C to +33 °C. The liver results are independent of sample thicknesses from 3 mm down to 100 μm and agree with available literature for non-mouse liver to within the measurement scatter.

  10. Uncertainty Quantification Techniques for Sensor Calibration Monitoring in Nuclear Power Plants

    Energy Technology Data Exchange (ETDEWEB)

    Ramuhalli, Pradeep; Lin, Guang; Crawford, Susan L.; Konomi, Bledar A.; Coble, Jamie B.; Shumaker, Brent; Hashemian, Hash

    2014-04-30

    This report describes research towards the development of advanced algorithms for online calibration monitoring. The objective of this research is to develop the next generation of online monitoring technologies for sensor calibration interval extension and signal validation in operating and new reactors. These advances are expected to improve the safety and reliability of current and planned nuclear power systems as a result of higher accuracies and increased reliability of sensors used to monitor key parameters. The focus of this report is on documenting the outcomes of the first phase of R&D under this project, which addressed approaches to uncertainty quantification (UQ) in online monitoring that are data-driven, and can therefore adjust estimates of uncertainty as measurement conditions change. Such data-driven approaches to UQ are necessary to address changing plant conditions, for example, as nuclear power plants experience transients, or as next-generation small modular reactors (SMR) operate in load-following conditions.

  11. Uncertainty Quantification Techniques for Sensor Calibration Monitoring in Nuclear Power Plants

    Energy Technology Data Exchange (ETDEWEB)

    Ramuhalli, Pradeep; Lin, Guang; Crawford, Susan L.; Konomi, Bledar A.; Braatz, Brett G.; Coble, Jamie B.; Shumaker, Brent; Hashemian, Hash

    2013-09-01

    This report describes the status of ongoing research towards the development of advanced algorithms for online calibration monitoring. The objective of this research is to develop the next generation of online monitoring technologies for sensor calibration interval extension and signal validation in operating and new reactors. These advances are expected to improve the safety and reliability of current and planned nuclear power systems as a result of higher accuracies and increased reliability of sensors used to monitor key parameters. The focus of this report is on documenting the outcomes of the first phase of R&D under this project, which addressed approaches to uncertainty quantification (UQ) in online monitoring that are data-driven, and can therefore adjust estimates of uncertainty as measurement conditions change. Such data-driven approaches to UQ are necessary to address changing plant conditions, for example, as nuclear power plants experience transients, or as next-generation small modular reactors (SMR) operate in load-following conditions.

  12. Discrimination of honeys using colorimetric sensor arrays, sensory analysis and gas chromatography techniques.

    Science.gov (United States)

    Tahir, Haroon Elrasheid; Xiaobo, Zou; Xiaowei, Huang; Jiyong, Shi; Mariod, Abdalbasit Adam

    2016-09-01

    Aroma profiles of six honey varieties of different botanical origins were investigated using colorimetric sensor array, gas chromatography-mass spectrometry (GC-MS) and descriptive sensory analysis. Fifty-eight aroma compounds were identified, including 2 norisoprenoids, 5 hydrocarbons, 4 terpenes, 6 phenols, 7 ketones, 9 acids, 12 aldehydes and 13 alcohols. Twenty abundant or active compounds were chosen as key compounds to characterize honey aroma. Discrimination of the honeys was subsequently implemented using multivariate analysis, including hierarchical clustering analysis (HCA) and principal component analysis (PCA). Honeys of the same botanical origin were grouped together in the PCA score plot and HCA dendrogram. SPME-GC/MS and colorimetric sensor array were able to discriminate the honeys effectively with the advantages of being rapid, simple and low-cost. Moreover, partial least squares regression (PLSR) was applied to indicate the relationship between sensory descriptors and aroma compounds. Copyright © 2016 Elsevier Ltd. All rights reserved.

  13. The development of gamma energy identify algorithm for compact radiation sensors using stepwise refinement technique

    Energy Technology Data Exchange (ETDEWEB)

    Yoo, Hyun Jun [Div. of Radiation Regulation, Korea Institute of Nuclear Safety, Daejeon (Korea, Republic of); Kim, Ye Won; Kim, Hyun Duk; Cho, Gyu Seong [Dept. of Nuclear and Quantum Engineering, Korea Advanced Institute of Science and Technology, Daejeon (Korea, Republic of); Yi, Yun [Dept. of of Electronics and Information Engineering, Korea University, Seoul (Korea, Republic of)

    2017-06-15

    A gamma energy identifying algorithm using spectral decomposition combined with smoothing method was suggested to confirm the existence of the artificial radio isotopes. The algorithm is composed by original pattern recognition method and smoothing method to enhance the performance to identify gamma energy of radiation sensors that have low energy resolution. The gamma energy identifying algorithm for the compact radiation sensor is a three-step of refinement process. Firstly, the magnitude set is calculated by the original spectral decomposition. Secondly, the magnitude of modeling error in the magnitude set is reduced by the smoothing method. Thirdly, the expected gamma energy is finally decided based on the enhanced magnitude set as a result of the spectral decomposition with the smoothing method. The algorithm was optimized for the designed radiation sensor composed of a CsI (Tl) scintillator and a silicon pin diode. The two performance parameters used to estimate the algorithm are the accuracy of expected gamma energy and the number of repeated calculations. The original gamma energy was accurately identified with the single energy of gamma radiation by adapting this modeling error reduction method. Also the average error decreased by half with the multi energies of gamma radiation in comparison to the original spectral decomposition. In addition, the number of repeated calculations also decreased by half even in low fluence conditions under 104 (/0.09 cm{sup 2} of the scintillator surface). Through the development of this algorithm, we have confirmed the possibility of developing a product that can identify artificial radionuclides nearby using inexpensive radiation sensors that are easy to use by the public. Therefore, it can contribute to reduce the anxiety of the public exposure by determining the presence of artificial radionuclides in the vicinity.

  14. Dynamic pressure sensor calibration techniques offering expanded bandwidth with increased resolution

    Science.gov (United States)

    Wisniewiski, David

    2015-03-01

    Advancements in the aerospace, defense and energy markets are being made possible by increasingly more sophisticated systems and sub-systems which rely upon critical information to be conveyed from the physical environment being monitored through ever more specialized, extreme environment sensing components. One sensing parameter of particular interest is dynamic pressure measurement. Crossing the boundary of all three markets (i.e. aerospace, defense and energy) is dynamic pressure sensing which is used in research and development of gas turbine technology, and subsequently embedded into a control loop used for long-term monitoring. Applications include quantifying the effects of aircraft boundary layer ingestion into the engine inlet to provide a reliable and robust design. Another application includes optimization of combustor dynamics by "listening" to the acoustic signature so that fuel-to-air mixture can be adjusted in real-time to provide cost operating efficiencies and reduced NOx emissions. With the vast majority of pressure sensors supplied today being calibrated either statically or "quasi" statically, the dynamic response characterization of the frequency dependent sensitivity (i.e. transfer function) of the pressure sensor is noticeably absent. The shock tube has been shown to be an efficient vehicle to provide frequency response of pressure sensors from extremely high frequencies down to 500 Hz. Recent development activity has lowered this starting frequency; thereby augmenting the calibration bandwidth with increased frequency resolution so that as the pressure sensor is used in an actual test application, more understanding of the physical measurement can be ascertained by the end-user.

  15. Highly Sensitive and Wide-Dynamic-Range Multichannel Optical-Fiber pH Sensor Based on PWM Technique

    OpenAIRE

    Md. Rajibur Rahaman Khan; Shin-Won Kang

    2016-01-01

    In this study, we propose a highly sensitive multichannel pH sensor that is based on an optical-fiber pulse width modulation (PWM) technique. According to the optical-fiber PWM method, the received sensing signal?s pulse width changes when the optical-fiber pH sensing-element of the array comes into contact with pH buffer solutions. The proposed optical-fiber PWM pH-sensing system offers a linear sensing response over a wide range of pH values from 2 to 12, with a high pH-sensing ability. The...

  16. Least-squares wave-front reconstruction of Shack-Hartmann sensors and shearing interferometers using multigrid techniques

    International Nuclear Information System (INIS)

    Baker, K.L.

    2005-01-01

    This article details a multigrid algorithm that is suitable for least-squares wave-front reconstruction of Shack-Hartmann and shearing interferometer wave-front sensors. The algorithm detailed in this article is shown to scale with the number of subapertures in the same fashion as fast Fourier transform techniques, making it suitable for use in applications requiring a large number of subapertures and high Strehl ratio systems such as for high spatial frequency characterization of high-density plasmas, optics metrology, and multiconjugate and extreme adaptive optics systems

  17. A new and efficient transient noise analysis technique for simulation of CCD image sensors or particle detectors

    International Nuclear Information System (INIS)

    Bolcato, P.; Jarron, P.; Poujois, R.

    1993-01-01

    CCD image sensors or switched capacitor circuits used for particle detectors have a certain noise level affecting the resolution of the detector. A new noise simulation technique for these devices is presented that has been implemented in the circuit simulator ELDO. The approach is particularly useful for noise simulation in analog sampling circuits. Comparison between simulations and experimental results has been made and is shown for a 1.5 μ CMOS current mode amplifier designed for high-rate particle detectors. (R.P.) 5 refs., 7 figs

  18. A Full Parallel Event Driven Readout Technique for Area Array SPAD FLIM Image Sensors

    Directory of Open Access Journals (Sweden)

    Kaiming Nie

    2016-01-01

    Full Text Available This paper presents a full parallel event driven readout method which is implemented in an area array single-photon avalanche diode (SPAD image sensor for high-speed fluorescence lifetime imaging microscopy (FLIM. The sensor only records and reads out effective time and position information by adopting full parallel event driven readout method, aiming at reducing the amount of data. The image sensor includes four 8 × 8 pixel arrays. In each array, four time-to-digital converters (TDCs are used to quantize the time of photons’ arrival, and two address record modules are used to record the column and row information. In this work, Monte Carlo simulations were performed in Matlab in terms of the pile-up effect induced by the readout method. The sensor’s resolution is 16 × 16. The time resolution of TDCs is 97.6 ps and the quantization range is 100 ns. The readout frame rate is 10 Mfps, and the maximum imaging frame rate is 100 fps. The chip’s output bandwidth is 720 MHz with an average power of 15 mW. The lifetime resolvability range is 5–20 ns, and the average error of estimated fluorescence lifetimes is below 1% by employing CMM to estimate lifetimes.

  19. Low Computational-Cost Footprint Deformities Diagnosis Sensor through Angles, Dimensions Analysis and Image Processing Techniques

    Directory of Open Access Journals (Sweden)

    J. Rodolfo Maestre-Rendon

    2017-11-01

    Full Text Available Manual measurements of foot anthropometry can lead to errors since this task involves the experience of the specialist who performs them, resulting in different subjective measures from the same footprint. Moreover, some of the diagnoses that are given to classify a footprint deformity are based on a qualitative interpretation by the physician; there is no quantitative interpretation of the footprint. The importance of providing a correct and accurate diagnosis lies in the need to ensure that an appropriate treatment is provided for the improvement of the patient without risking his or her health. Therefore, this article presents a smart sensor that integrates the capture of the footprint, a low computational-cost analysis of the image and the interpretation of the results through a quantitative evaluation. The smart sensor implemented required the use of a camera (Logitech C920 connected to a Raspberry Pi 3, where a graphical interface was made for the capture and processing of the image, and it was adapted to a podoscope conventionally used by specialists such as orthopedist, physiotherapists and podiatrists. The footprint diagnosis smart sensor (FPDSS has proven to be robust to different types of deformity, precise, sensitive and correlated in 0.99 with the measurements from the digitalized image of the ink mat.

  20. Thermal expansion and density measurements of molten and solid materials at high temperatures by the gamma attenuation technique

    International Nuclear Information System (INIS)

    Drotning, W.D.

    1979-05-01

    An apparatus is described for the measurement of the density and thermal expansion of molten materials to 3200 0 K using the gamma attenuation technique. The precision of the experimental technique was analytically examined for both absolute and relative density determinations. Three analytical expressions used to reduce data for liquid density determinations were evaluated for their precision. Each allows use of a different set of input data parameters, which can be chosen based on experimental considerations. Using experimentally reasonable values for the precision of the parameters yields a similar resultant density precision from the three methods, on the order of 0.2%. The analytical method for measurements of the linear thermal expansion of solids by the gamma method is also described. To demonstrate the use of the technique on reasonably well-characterized systems, data are presented for (1) the density and thermal expansion of molten tin, lead, and aluminum to 1300 0 K, (2) the thermal expansion of solid aluminum to the melting point, and (3) the thermal expansion of a low melting point glass through the transition temperature and melting region. The data agree very well with published results using other methods where such published data exist

  1. The measuring technique developed to evaluate the thermal diffusivity of the multi-layered thin film specimens

    Directory of Open Access Journals (Sweden)

    Li Tse-Chang

    2017-01-01

    Full Text Available In the present study, the thermal diffusivities of the Al, Si and ITO films deposited on the SUS304 steel substrate are evaluated via the present technique. Before applying this technique, the temperature for the thin film of the multi-layered specimen is developed theoretically for the one- dimensional steady heat conduction in response to amplitude and frequency of the periodically oscillating temperature imposed by a peltier placed beneath the specimen's substrate. By the thermal-electrical data processing system excluding the lock-in amplifier, the temperature frequency a3 has been proved first to be independent of the electrical voltage applied to the peltier and the contact position of the thermocouples. The experimental data of phase difference for three kinds of specimen are regressed well by a straight line with a slope. Then, the thermal diffusivity of the thin film is thus determined if the slope value and the film- thickness are available. In the present arrangements for the thermocouples, two thermal diffusivity values are quite close each other and valid for every kind of specimen. This technique can provide an efficient, low-cost method for the thermal diffusivity measurements of thin films.

  2. Life Management Technique of Thermal Fatigue for SMST Boiler Tube at Different Heating Zone Using Smithy Furnace

    OpenAIRE

    Shekhar Pal,; Pradeep Suman

    2014-01-01

    This paper highlights on the evaluation of thermal fatigue failure for SMST (Salzgitter Mannesmann strain less boiler tube) DMV 304 HCu boiler tube using life management technique by using of smithy furnace. Boiler tubes are highly affected by operating conditions like, high temperature and high pressure. So it needs periodic checking for the purpose of safety and health assessment of the plant. So using this technique we can identify the degradation of tubes at microstructure...

  3. Thermal behaviour of hafnium diethylenetriaminepentaacetate studied using the perturbed angular correlation technique

    Energy Technology Data Exchange (ETDEWEB)

    Chain, Cecilia Y. [Universidad Nacional de La Plata (Argentina). Dept. de Fisica; Consejo Nacional de Investigaciones Cientificas y Tecnicas (CONICET), La Plata (Argentina). IFLP-CCT; Consejo Nacional de Investigaciones Cientificas y Tecnicas, Buenos Aires (Argentina); Rivas, Patricia [Consejo Nacional de Investigaciones Cientificas y Tecnicas (CONICET), La Plata (Argentina). IFLP-CCT; Consejo Nacional de Investigaciones Cientificas y Tecnicas, Buenos Aires (Argentina); Universidad Nacional de La Plata (Argentina). Facultad de Ciencias Agrarias y Forestales; Pasquevich, Alberto F. [Universidad Nacional de La Plata (Argentina). Dept. de Fisica; Consejo Nacional de Investigaciones Cientificas y Tecnicas (CONICET), La Plata (Argentina). IFLP-CCT; Comision de Investigaciones Cientificas de la Provincia de Buenos Aires (CIC-PBA) (Argentina)

    2014-07-01

    Polyaminecarboxilic ligands like diethylenetriaminepentaacetic acid form stable complexes with many heavy metal ions, excelling as cation chelants especially in the field of radiopharmacy. The aim of this work is to characterize, by using the Time Differential Perturbed Angular Correlations (TDPAC) technique, the hyperfine interactions at hafnium sites in hafnium diethylenetriaminepentaacetate and to investigate their evolution as temperature increases. TDPAC results for KHfDTPA.3H{sub 2}O obtained by chemical synthesis yield a well defined and highly asymmetric interaction of quadrupole frequency ω{sub Q} = 141 Mrad/s, which is consistent with the existence of a unique site for the metal in the crystal lattice. The thermal behaviour of the chelate is investigated by means of differential scanning calorimetry and thermogravimetrical analyses revealing that an endothermic dehydration of KHfDTPA.3H{sub 2}O takes place in one step between 80 C and 180 C. The anhydrous KHfDTPA thus arising is characterized by a fully asymmetric and well defined interaction of quadrupole frequency ω{sub Q} = 168 Mrad/s. (orig.)

  4. Thermal behaviour of hafnium diethylenetriaminepentaacetate studied using the perturbed angular correlation technique

    International Nuclear Information System (INIS)

    Chain, Cecilia Y.; Rivas, Patricia

    2014-01-01

    Polyaminecarboxilic ligands like diethylenetriaminepentaacetic acid form stable complexes with many heavy metal ions, excelling as cation chelants especially in the field of radiopharmacy. The aim of this work is to characterize, by using the Time Differential Perturbed Angular Correlations (TDPAC) technique, the hyperfine interactions at hafnium sites in hafnium diethylenetriaminepentaacetate and to investigate their evolution as temperature increases. TDPAC results for KHfDTPA.3H 2 O obtained by chemical synthesis yield a well defined and highly asymmetric interaction of quadrupole frequency ω Q = 141 Mrad/s, which is consistent with the existence of a unique site for the metal in the crystal lattice. The thermal behaviour of the chelate is investigated by means of differential scanning calorimetry and thermogravimetrical analyses revealing that an endothermic dehydration of KHfDTPA.3H 2 O takes place in one step between 80 C and 180 C. The anhydrous KHfDTPA thus arising is characterized by a fully asymmetric and well defined interaction of quadrupole frequency ω Q = 168 Mrad/s. (orig.)

  5. Studies of implicit and explicit solution techniques in transient thermal analysis of structures

    International Nuclear Information System (INIS)

    Adelman, H.M.; Haftka, R.T.; Robinson, J.C.

    1982-08-01

    Studies aimed at an increase in the efficiency of calculating transient temperature fields in complex aerospace vehicle structures are reported. The advantages and disadvantages of explicit and implicit algorithms are discussed and a promising set of implicit algorithms with variable time steps, known as GEARIB, is described. Test problems, used for evaluating and comparing various algorithms, are discussed and finite element models of the configurations are described. These problems include a coarse model of the Space Shuttle wing, an insulated frame test article, a metallic panel for a thermal protection system, and detailed models of sections of the Space Shuttle wing. Results generally indicate a preference for implicit over explicit algorithms for transient structural heat transfer problems when the governing equations are stiff (typical of many practical problems such as insulated metal structures). The effects on algorithm performance of different models of an insulated cylinder are demonstrated. The stiffness of the problem is highly sensitive to modeling details and careful modeling can reduce the stiffness of the equations to the extent that explicit methods may become the best choice. Preliminary applications of a mixed implicit-explicit algorithm and operator splitting techniques for speeding up the solution of the algebraic equations are also described

  6. Studies of implicit and explicit solution techniques in transient thermal analysis of structures

    Science.gov (United States)

    Adelman, H. M.; Haftka, R. T.; Robinson, J. C.

    1982-01-01

    Studies aimed at an increase in the efficiency of calculating transient temperature fields in complex aerospace vehicle structures are reported. The advantages and disadvantages of explicit and implicit algorithms are discussed and a promising set of implicit algorithms with variable time steps, known as GEARIB, is described. Test problems, used for evaluating and comparing various algorithms, are discussed and finite element models of the configurations are described. These problems include a coarse model of the Space Shuttle wing, an insulated frame tst article, a metallic panel for a thermal protection system, and detailed models of sections of the Space Shuttle wing. Results generally indicate a preference for implicit over explicit algorithms for transient structural heat transfer problems when the governing equations are stiff (typical of many practical problems such as insulated metal structures). The effects on algorithm performance of different models of an insulated cylinder are demonstrated. The stiffness of the problem is highly sensitive to modeling details and careful modeling can reduce the stiffness of the equations to the extent that explicit methods may become the best choice. Preliminary applications of a mixed implicit-explicit algorithm and operator splitting techniques for speeding up the solution of the algebraic equations are also described.

  7. The low thermal gradient CZ technique as a way of growing of dislocation-free germanium crystals

    Science.gov (United States)

    Moskovskih, V. A.; Kasimkin, P. V.; Shlegel, V. N.; Vasiliev, Y. V.; Gridchin, V. A.; Podkopaev, O. I.

    2014-09-01

    This paper considers the possibility of growth of dislocation-free germanium single crystals. This is achieved by reducing the temperature gradients at the level of 1 K/cm and lower. Single germanium crystals 45-48 mm in diameter with a dislocation density of 102 cm-2 were grown by a Low Thermal Gradient Czochralski technique (LTG CZ).

  8. Study of the aging processes in polyurethane adhesives using thermal treatment and differential calorimetric, dielectric, and mechanical techniques ; 1, identifying the aging processes ; 2, quantifying the aging effect

    CERN Document Server

    Althouse, L P

    1979-01-01

    Study of the aging processes in polyurethane adhesives using thermal treatment and differential calorimetric, dielectric, and mechanical techniques ; 1, identifying the aging processes ; 2, quantifying the aging effect

  9. Assessment of laser ablation techniques in a-si technologies for position-sensor development

    Science.gov (United States)

    Molpeceres, C.; Lauzurica, S.; Ocana, J. L.; Gandia, J. J.; Urbina, L.; Carabe, J.

    2005-07-01

    Laser micromachining of semiconductor and Transparent Conductive Oxides (TCO) materials is very important for the practical applications in photovoltaic industry. In particular, a problem of controlled ablation of those materials with minimum of debris and small heat affected zone is one of the most vital for the successful implementation of laser micromachining. In particular, selective ablation of thin films for the development of new photovoltaic panels and sensoring devices based on amorphous silicon (a-Si) is an emerging field, in which laser micromachining systems appear as appropriate tools for process development and device fabrication. In particular, a promising application is the development of purely photovoltaic position sensors. Standard p-i-n or Schottky configurations using Transparent Conductive Oxides (TCO), a-Si and metals are especially well suited for these applications, appearing selective laser ablation as an ideal process for controlled material patterning and isolation. In this work a detailed study of laser ablation of a widely used TCO, Indium-tin-oxide (ITO), and a-Si thin films of different thicknesses is presented, with special emphasis on the morphological analysis of the generated grooves. The profiles of ablated grooves have been studied in order to determine the best processing conditions, i.e. laser pulse energy and wavelength, and to asses this technology as potentially competitive to standard photolithographic processes. The encouraging results obtained, with well defined ablation grooves having thicknesses in the order of 10 μm both in ITO and a-Si, open up the possibility of developing a high-performance double Schottky photovoltaic matrix position sensor.

  10. A Comparison of Inductive Sensors in the Characterization of Partial Discharges and Electrical Noise Using the Chromatic Technique

    Directory of Open Access Journals (Sweden)

    Jorge Alfredo Ardila-Rey

    2018-03-01

    Full Text Available Partial discharges (PDs are one of the most important classes of ageing processes that occur within electrical insulation. PD detection is a standardized technique to qualify the state of the insulation in electric assets such as machines and power cables. Generally, the classical phase-resolved partial discharge (PRPD patterns are used to perform the identification of the type of PD source when they are related to a specific degradation process and when the electrical noise level is low compared to the magnitudes of the PD signals. However, in practical applications such as measurements carried out in the field or in industrial environments, several PD sources and large noise signals are usually present simultaneously. In this study, three different inductive sensors have been used to evaluate and compare their performance in the detection and separation of multiple PD sources by applying the chromatic technique to each of the measured signals.

  11. A Comparison of Inductive Sensors in the Characterization of Partial Discharges and Electrical Noise Using the Chromatic Technique.

    Science.gov (United States)

    Ardila-Rey, Jorge Alfredo; Montaña, Johny; de Castro, Bruno Albuquerque; Schurch, Roger; Covolan Ulson, José Alfredo; Muhammad-Sukki, Firdaus; Bani, Nurul Aini

    2018-03-29

    Partial discharges (PDs) are one of the most important classes of ageing processes that occur within electrical insulation. PD detection is a standardized technique to qualify the state of the insulation in electric assets such as machines and power cables. Generally, the classical phase-resolved partial discharge (PRPD) patterns are used to perform the identification of the type of PD source when they are related to a specific degradation process and when the electrical noise level is low compared to the magnitudes of the PD signals. However, in practical applications such as measurements carried out in the field or in industrial environments, several PD sources and large noise signals are usually present simultaneously. In this study, three different inductive sensors have been used to evaluate and compare their performance in the detection and separation of multiple PD sources by applying the chromatic technique to each of the measured signals.

  12. First experience from in-core sensor validation based on correlation and neuro-fuzzy techniques

    International Nuclear Information System (INIS)

    Figedy, S.

    2011-01-01

    In this work new types of nuclear reactor in-core sensor validation methods are outlined. The first one is based on combination of correlation coefficients and mutual information indices, which reflect the correlation of signals in linear and nonlinear regions. The method may be supplemented by wavelet transform based signal features extraction and pattern recognition by artificial neural networks and also fuzzy logic based decision making. The second one is based on neuro-fuzzy modeling of residuals between experimental values and their theoretical counterparts obtained from the reactor core simulator calculations. The first experience with this approach is described and further improvements to enhance the outcome reliability are proposed (Author)

  13. A Dynamic Range Enhanced Readout Technique with a Two-Step TDC for High Speed Linear CMOS Image Sensors

    Directory of Open Access Journals (Sweden)

    Zhiyuan Gao

    2015-11-01

    Full Text Available This paper presents a dynamic range (DR enhanced readout technique with a two-step time-to-digital converter (TDC for high speed linear CMOS image sensors. A multi-capacitor and self-regulated capacitive trans-impedance amplifier (CTIA structure is employed to extend the dynamic range. The gain of the CTIA is auto adjusted by switching different capacitors to the integration node asynchronously according to the output voltage. A column-parallel ADC based on a two-step TDC is utilized to improve the conversion rate. The conversion is divided into coarse phase and fine phase. An error calibration scheme is also proposed to correct quantization errors caused by propagation delay skew within −Tclk~+Tclk. A linear CMOS image sensor pixel array is designed in the 0.13 μm CMOS process to verify this DR-enhanced high speed readout technique. The post simulation results indicate that the dynamic range of readout circuit is 99.02 dB and the ADC achieves 60.22 dB SNDR and 9.71 bit ENOB at a conversion rate of 2 MS/s after calibration, with 14.04 dB and 2.4 bit improvement, compared with SNDR and ENOB of that without calibration.

  14. Remote inspection with multi-copters, radiological sensors and SLAM techniques

    Science.gov (United States)

    Carvalho, Henrique; Vale, Alberto; Marques, Rúben; Ventura, Rodrigo; Brouwer, Yoeri; Gonçalves, Bruno

    2018-01-01

    Activated material can be found in different scenarios, such as in nuclear reactor facilities or medical facilities (e.g. in positron emission tomography commonly known as PET scanning). In addition, there are unexpected scenarios resulting from possible accidents, or where dangerous material is hidden for terrorism attacks using nuclear weapons. Thus, a technological solution is important to cope with fast and reliable remote inspection. The multi-copter is a common type of Unmanned Aerial Vehicle (UAV) that provides the ability to perform a first radiological inspection in the described scenarios. The paper proposes a solution with a multi-copter equipped with on-board sensors to perform a 3D reconstruction and a radiological mapping of the scenario. A depth camera and a Geiger-Müler counter are the used sensors. The inspection is performed in two steps: i) a 3D reconstruction of the environment and ii) radiation activity inference to localise and quantify sources of radiation. Experimental results were achieved with real 3D data and simulated radiation activity. Experimental tests with real sources of radiation are planned in the next iteration of the work.

  15. Remote inspection with multi-copters, radiological sensors and SLAM techniques

    Directory of Open Access Journals (Sweden)

    Carvalho Henrique

    2018-01-01

    Full Text Available Activated material can be found in different scenarios, such as in nuclear reactor facilities or medical facilities (e.g. in positron emission tomography commonly known as PET scanning. In addition, there are unexpected scenarios resulting from possible accidents, or where dangerous material is hidden for terrorism attacks using nuclear weapons. Thus, a technological solution is important to cope with fast and reliable remote inspection. The multi-copter is a common type of Unmanned Aerial Vehicle (UAV that provides the ability to perform a first radiological inspection in the described scenarios. The paper proposes a solution with a multi-copter equipped with on-board sensors to perform a 3D reconstruction and a radiological mapping of the scenario. A depth camera and a Geiger-Müler counter are the used sensors. The inspection is performed in two steps: i a 3D reconstruction of the environment and ii radiation activity inference to localise and quantify sources of radiation. Experimental results were achieved with real 3D data and simulated radiation activity. Experimental tests with real sources of radiation are planned in the next iteration of the work.

  16. Resource Optimization Techniques and Security Levels for Wireless Sensor Networks Based on the ARSy Framework

    Science.gov (United States)

    Kitagawa, Akio

    2018-01-01

    Wireless Sensor Networks (WSNs) with limited battery, central processing units (CPUs), and memory resources are a widely implemented technology for early warning detection systems. The main advantage of WSNs is their ability to be deployed in areas that are difficult to access by humans. In such areas, regular maintenance may be impossible; therefore, WSN devices must utilize their limited resources to operate for as long as possible, but longer operations require maintenance. One method of maintenance is to apply a resource adaptation policy when a system reaches a critical threshold. This study discusses the application of a security level adaptation model, such as an ARSy Framework, for using resources more efficiently. A single node comprising a Raspberry Pi 3 Model B and a DS18B20 temperature sensor were tested in a laboratory under normal and stressful conditions. The result shows that under normal conditions, the system operates approximately three times longer than under stressful conditions. Maintaining the stability of the resources also enables the security level of a network’s data output to stay at a high or medium level. PMID:29772773

  17. Modelling of thermal field and point defect dynamics during silicon single crystal growth using CZ technique

    Science.gov (United States)

    Sabanskis, A.; Virbulis, J.

    2018-05-01

    Mathematical modelling is employed to numerically analyse the dynamics of the Czochralski (CZ) silicon single crystal growth. The model is axisymmetric, its thermal part describes heat transfer by conduction and thermal radiation, and allows to predict the time-dependent shape of the crystal-melt interface. Besides the thermal field, the point defect dynamics is modelled using the finite element method. The considered process consists of cone growth and cylindrical phases, including a short period of a reduced crystal pull rate, and a power jump to avoid large diameter changes. The influence of the thermal stresses on the point defects is also investigated.

  18. The use of large area silicon sensors for thermal neutron detection

    International Nuclear Information System (INIS)

    Schulte, R.L.; Swanson, F.; Kesselman, M.

    1994-01-01

    The use of large area planar silicon detectors coupled with gadolinium foils has been investigated to develop a thermal neutron detector having a large area-efficiency (Aε) product. Noise levels due to high detector capacitance limit the size of silicon detectors that can be utilized. Calculations using the Monte Carlo code, MCNP, have been made to determine the variation of intrinsic detection efficiency as a function of the discriminator threshold level required to eliminate the detector noise. Measurements of the noise levels for planar silicon detectors of various resistivities (400, 3000 and 5000 Ω cm) have been made and the optimal detector area-efficiency products have been determined. The response of a Si-Gd-Si sandwich detector with areas between 1 cm 2 and 10.5 cm 2 is presented and the effects of the detector capacitance and reverse current are discussed. ((orig.))

  19. The use of large area silicon sensors for thermal neutron detection

    Energy Technology Data Exchange (ETDEWEB)

    Schulte, R.L. (Research and Development Center, Mail Stop: A01-26, Grumman Aerospace Corporation, Bethpage, NY 11714 (United States)); Swanson, F. (Research and Development Center, Mail Stop: A01-26, Grumman Aerospace Corporation, Bethpage, NY 11714 (United States)); Kesselman, M. (Research and Development Center, Mail Stop: A01-26, Grumman Aerospace Corporation, Bethpage, NY 11714 (United States))

    1994-12-30

    The use of large area planar silicon detectors coupled with gadolinium foils has been investigated to develop a thermal neutron detector having a large area-efficiency (A[epsilon]) product. Noise levels due to high detector capacitance limit the size of silicon detectors that can be utilized. Calculations using the Monte Carlo code, MCNP, have been made to determine the variation of intrinsic detection efficiency as a function of the discriminator threshold level required to eliminate the detector noise. Measurements of the noise levels for planar silicon detectors of various resistivities (400, 3000 and 5000 [Omega] cm) have been made and the optimal detector area-efficiency products have been determined. The response of a Si-Gd-Si sandwich detector with areas between 1 cm[sup 2] and 10.5 cm[sup 2] is presented and the effects of the detector capacitance and reverse current are discussed. ((orig.))

  20. Electronic thermal sensor and Data Collection Platform technology: Part 5 in Thermal surveillance of active volcanoes using the Landsat-1 Data Collection System

    Science.gov (United States)

    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.

  1. Leakage investigation in an underground cooling water pipeline at a thermal power station using radiotracer technique

    International Nuclear Information System (INIS)

    Khan, I.H.; Din, U.G.; Gul, S.; Farooq, M.; Qureshi, R.M.

    2004-05-01

    The objective of this study was to locate the leakage point(s) in an underground cooling water pipeline of a Thermal Power Station for pre-shutdown planning purposes. The internal diameter of the pipeline was 2240 mm with 12 mm with 12 (mild steel) wall thickness and it was buried under 1.0 meter reinforced concrete and 0.5-1.0 meter soil/sand cover. The volume flow rate of the pipeline was 29043 m/sup 3/hour at 2kg/cm/sup 2/ pressure. The linear speed of water flowing inside the pipeline was around 2 m/sec. This gave rise to a very high volume fast moving system. Radiotracer technique was used to investigate the problem under investigation. About 50 mCi of /sup 131/I radiotracer, in the form of NaI solution, was injected into the system and radiotracer evolution near suspected leakage point(s) was monitored using radiation detectors (NaI, 2 x 2 inch crystal size). Seven detectors were installed around three teeing off pipes (leakage area) inside the plant building and one at the injection point near the pump outlet. On line data acquisition system was used to acquire the radiotracer data. The leakage water was exiting from the floor just along the pipes carrying main flow of water. The time lag between the arrival, at detectors, of radiotracer flowing inside the pipeline and that present in the leakage water (outside the pipeline) was exploited to identify the position of leakage. The tracer test revealed that there was leakage at two points. The leakage at one point was small as compared at the other points. (author)

  2. Synthesis of carbon nanotubes using the cobalt nanocatalyst by thermal chemical vapor deposition technique

    Energy Technology Data Exchange (ETDEWEB)

    Madani, S.S. [Department of Chemistry, Science and Research Branch, Islamic Azad University, Tehran (Iran, Islamic Republic of); Zare, K. [Department of Chemistry, Science and Research Branch, Islamic Azad University, Tehran (Iran, Islamic Republic of); Department of Chemistry, Shahid Beheshti University, Tehran (Iran, Islamic Republic of); Ghoranneviss, M. [Plasma Physics Research Center, Science and Research Branch, Islamic Azad University, Tehran (Iran, Islamic Republic of); Salar Elahi, A., E-mail: Salari_phy@yahoo.com [Plasma Physics Research Center, Science and Research Branch, Islamic Azad University, Tehran (Iran, Islamic Republic of)

    2015-11-05

    The three main synthesis methods of Carbon nanotubes (CNTs) are the arc discharge, the laser ablation and the chemical vapour deposition (CVD) with a special regard to the latter one. CNTs were produced on a silicon wafer by Thermal Chemical Vapor Deposition (TCVD) using acetylene as a carbon source, cobalt as a catalyst and ammonia as a reactive gas. The DC-sputtering system was used to prepare cobalt thin films on Si substrates. A series of experiments was carried out to investigate the effects of reaction temperature and deposition time on the synthesis of the nanotubes. The deposition time was selected as 15 and 25 min for all growth temperatures. Energy Dispersive X-ray (EDX) measurements were used to investigate the elemental composition of the Co nanocatalyst deposited on Si substrates. Atomic Force Microscopy (AFM) was used to characterize the surface topography of the Co nanocatalyst deposited on Si substrates. The as-grown CNTs were characterized under Field Emission Scanning Electron Microscopy (FESEM) to study the morphological properties of CNTs. Also, the grown CNTs have been investigated by High Resolution Transmission Electron Microscopy (HRTEM) and Raman spectroscopy. The results demonstrated that increasing the temperature leads to increasing the diameter of CNTs. The ideal reaction temperature was 850 °C and the deposition time was 15 min. - Graphical abstract: FESEM images of CNTs grown on the cobalt catalyst at growth temperatures of (a) 850 °C, (b) 900 °C, (c) 950 °C and (d) 1000 °C during the deposition time of 15 min. - Highlights: • Carbon nanotubes (CNTs) were produced on a silicon wafer by TCVD technique. • EDX and AFM were used to investigate the elemental composition and surface topography. • FESEM was used to study the morphological properties of CNTs. • The grown CNTs have been investigated by HRTEM and Raman spectroscopy.

  3. Some application of the thermal analysis technique to nuclear material process

    International Nuclear Information System (INIS)

    Xi Chongpu.

    1987-01-01

    This paper briefly described the thermal stability and phase transformation of Uranium Compounds as UF 4 , UO 2 F 2 , UO 2 -(NO 3 ) 2 , ADU, AUC, UO 3 and UO 2 . It proved that the thermal analysis finds extensive application in nuclear materials prodcution

  4. Industrial implementation of plasma deposition using the expanding thermal plasma technique

    NARCIS (Netherlands)

    Sanden, van de M.C.M.; Oever, van den P.J.; Creatore, M.; Schaepkens, M.; Miebach, T.; Iacovangelo, C.D.; Bosch, R.C.M.; Bijker, M.D.; Evers, M.F.J.; Schram, D.C.; Kessels, W.M.M.

    2004-01-01

    Two successful industrial implementations of the expanding thermal plasma setup, a novel plasma source, obtaining high deposition rate are discussed. The Ar/O2/hexamethyldisiloxane and Ar/O2/octamethyl-cyclosiloxane-fed expanding thermal plasma setup is used to deposit scratch resistant silicone

  5. Experimental investigation for determination of thermal effects in a Nd: YAG laser crystal by use of interferometry technique

    International Nuclear Information System (INIS)

    Safary, E.; Movahedinejad, H.; Razzaghi, H.; Haj Esmaeilbeigi, F.; Tohidi, T.; Shiri, M.

    2007-01-01

    Thermal effects have an important role in high power solid state laser designing. Known of this effect and their roles on intensity and quality of output beam needs so many experiments. In this paper, we focused on influence of temperature distribution on thermal lensing in the Nd:YAG laser by use of interferometry technique. Then we used from a plariscop set up for describing of intensity reduce and distortion of the wave shape when it use from the Polaroid into the resonator at side pump.

  6. Applying Fuzzy Logic and Data Mining Techniques in Wireless Sensor Network for Determination Residential Fire Confidence

    Directory of Open Access Journals (Sweden)

    Mirjana Maksimović

    2014-09-01

    Full Text Available The main goal of soft computing technologies (fuzzy logic, neural networks, fuzzy rule-based systems, data mining techniques… is to find and describe the structural patterns in the data in order to try to explain connections between data and on their basis create predictive or descriptive models. Integration of these technologies in sensor nodes seems to be a good idea because it can significantly lead to network performances improvements, above all to reduce the energy consumption and enhance the lifetime of the network. The purpose of this paper is to analyze different algorithms in the case of fire confidence determination in order to see which of the methods and parameter values work best for the given problem. Hence, an analysis between different classification algorithms in a case of nominal and numerical d

  7. An Analysis of the Guided Wave Patterns in a Small-bore Titanium Tube by a Magnetostrictive Sensor Technique

    International Nuclear Information System (INIS)

    Cheong, Yong-Moo; Kim, Shin

    2007-01-01

    The presence of damage or defects in pipes or tubes is one of the major problems in nuclear power plants. However, in many cases, it is difficult to inspect all of them by the conventional ultrasonic methods, because of their geometrical complexity and inaccessibility. The magnetostrictive guided wave technique has several advantages for practical applications, such as a 100- percent volumetric coverage of a long segment of a structure, a reduced inspection time and its cost effectiveness, as well as its' relatively simple structure. One promising feature of the magnetostrictive sensor technique is that the wave patterns are relatively clear and simple compared to the conventional piezoelectric ultrasonic transducer. If we can characterize the evolution of the defect signals, it can be a promising tool for a structural health monitoring of pipes for a long period as well as the identification of flaws. An in-bore guided wave probe was developed for an application to small bore heat exchanger tubes. The magnetostrictive probe installed on the hollow cylindrical waveguide generates and detects torsional waves in the waveguide. This waveguide is expanded by the draw bar to create an intimate mechanical contact between the waveguide and the inside surface of the tube being tested. In this paper, we analyzed the wave patterns reflected from various artificial holes in a titanium tube, which is used in the condenser in a nuclear power plant. The torsional guided waves were generated and received by a coil and a DC magnetized nickel strip as well as an inbore guided wave probe. The wave patterns from various defects were compared with two different sensor techniques and a detectable limit of the defected was estimated

  8. Reduction of thermal models of buildings: improvement of techniques using meteorological influence models; Reduction de modeles thermiques de batiments: amelioration des techniques par modelisation des sollicitations meteorologiques

    Energy Technology Data Exchange (ETDEWEB)

    Dautin, S.

    1997-04-01

    This work concerns the modeling of thermal phenomena inside buildings for the evaluation of energy exploitation costs of thermal installations and for the modeling of thermal and aeraulic transient phenomena. This thesis comprises 7 chapters dealing with: (1) the thermal phenomena inside buildings and the CLIM2000 calculation code, (2) the ETNA and GENEC experimental cells and their modeling, (3) the techniques of model reduction tested (Marshall`s truncature, Michailesco aggregation method and Moore truncature) with their algorithms and their encoding in the MATRED software, (4) the application of model reduction methods to the GENEC and ETNA cells and to a medium size dual-zone building, (5) the modeling of meteorological influences classically applied to buildings (external temperature and solar flux), (6) the analytical expression of these modeled meteorological influences. The last chapter presents the results of these improved methods on the GENEC and ETNA cells and on a lower inertia building. These new methods are compared to classical methods. (J.S.) 69 refs.

  9. Ground-based thermal imaging of stream surface temperatures: Technique and evaluation

    Science.gov (United States)

    Bonar, Scott A.; Petre, Sally J.

    2015-01-01

    We evaluated a ground-based handheld thermal imaging system for measuring water temperatures using data from eight southwestern USA streams and rivers. We found handheld thermal imagers could provide considerably more spatial information on water temperature (for our unit one image = 19,600 individual temperature measurements) than traditional methods could supply without a prohibitive amount of effort. Furthermore, they could provide measurements of stream surface temperature almost instantaneously compared with most traditional handheld thermometers (e.g., >20 s/reading). Spatial temperature analysis is important for measurement of subtle temperature differences across waterways, and identification of warm and cold groundwater inputs. Handheld thermal imaging is less expensive and equipment intensive than airborne thermal imaging methods and is useful under riparian canopies. Disadvantages of handheld thermal imagers include their current higher expense than thermometers, their susceptibility to interference when used incorrectly, and their slightly lower accuracy than traditional temperature measurement methods. Thermal imagers can only measure surface temperature, but this usually corresponds to subsurface temperatures in well-mixed streams and rivers. Using thermal imaging in select applications, such as where spatial investigations of water temperature are needed, or in conjunction with stationary temperature data loggers or handheld electronic or liquid-in-glass thermometers to characterize stream temperatures by both time and space, could provide valuable information on stream temperature dynamics. These tools will become increasingly important to fisheries biologists as costs continue to decline.

  10. Interference Mitigation Technique Using Active Spaceborne Sensor Antenna in EESS (Active) and Space Research Service (Active) for Use in 500 MHz Bandwidth Near 9.6 GHz

    Science.gov (United States)

    Huneycutt, Bryan L.

    2005-01-01

    This document presents an interference mitigation technique using the active spaceborne sensor SAR3 antenna in the Earth Exploration-Satellite Service (active) and Space Research Service (active) for use in a 500 MHz bandwidth near 9.6 GHz. The purpose of the document is present antenna designs which offer lower sidelobes and faster rolloff in the sidelobes which in turn mitigates the interference to other services from the EESS (active) and SRS (active) sensors.

  11. Fiber Bragg Grating Temperature Sensors in a 6.5-MW Generator Exciter Bridge and the Development and Simulation of Its Thermal Model

    Directory of Open Access Journals (Sweden)

    Kleiton de Morais Sousa

    2014-09-01

    Full Text Available This work reports the thermal modeling and characterization of a thyristor. The thyristor is used in a 6.5-MW generator excitation bridge. Temperature measurements are performed using fiber Bragg grating (FBG sensors. These sensors have the benefits of being totally passive and immune to electromagnetic interference and also multiplexed in a single fiber. The thyristor thermal model consists of a second order equivalent electric circuit, and its power losses lead to an increase in temperature, while the losses are calculated on the basis of the excitation current in the generator. Six multiplexed FBGs are used to measure temperature and are embedded to avoid the effect of the strain sensitivity. The presented results show a relationship between field current and temperature oscillation and prove that this current can be used to determine the thermal model of a thyristor. The thermal model simulation presents an error of 1.5 °C, while the FBG used allows for the determination of the thermal behavior and the field current dependence. Since the temperature is a function of the field current, the corresponding simulation can be used to estimate the temperature in the thyristors.

  12. Fiber Bragg grating temperature sensors in a 6.5-MW generator exciter bridge and the development and simulation of its thermal model.

    Science.gov (United States)

    de Morais Sousa, Kleiton; Probst, Werner; Bortolotti, Fernando; Martelli, Cicero; da Silva, Jean Carlos Cardozo

    2014-09-05

    This work reports the thermal modeling and characterization of a thyristor. The thyristor is used in a 6.5-MW generator excitation bridge. Temperature measurements are performed using fiber Bragg grating (FBG) sensors. These sensors have the benefits of being totally passive and immune to electromagnetic interference and also multiplexed in a single fiber. The thyristor thermal model consists of a second order equivalent electric circuit, and its power losses lead to an increase in temperature, while the losses are calculated on the basis of the excitation current in the generator. Six multiplexed FBGs are used to measure temperature and are embedded to avoid the effect of the strain sensitivity. The presented results show a relationship between field current and temperature oscillation and prove that this current can be used to determine the thermal model of a thyristor. The thermal model simulation presents an error of 1.5 °C, while the FBG used allows for the determination of the thermal behavior and the field current dependence. Since the temperature is a function of the field current, the corresponding simulation can be used to estimate the temperature in the thyristors.

  13. Remote Sensing Analysis Techniques and Sensor Requirements to Support the Mapping of Illegal Domestic Waste Disposal Sites in Queensland, Australia

    Directory of Open Access Journals (Sweden)

    Katharine Glanville

    2015-10-01

    Full Text Available Illegal disposal of waste is a significant management issue for contemporary governments with waste posing an economic, social, and environmental risk. An improved understanding of the distribution of illegal waste disposal sites is critical to enhance the cost-effectiveness and efficiency of waste management efforts. Remotely sensed data has the potential to address this knowledge gap. However, the literature regarding the use of remote sensing to map illegal waste disposal sites is incomplete. This paper aims to analyze existing remote sensing methods and sensors used to monitor and map illegal waste disposal sites. The purpose of this paper is to support the evaluation of existing remote sensing methods for mapping illegal domestic waste sites in Queensland, Australia. Recent advances in technology and the acquisition of very high-resolution remote sensing imagery provide an important opportunity to (1 revisit established analysis techniques for identifying illegal waste disposal sites, (2 examine the applicability of different remote sensors for illegal waste disposal detection, and (3 identify opportunities for future research to increase the accuracy of any illegal waste disposal mapping products.

  14. A Two-Step A/D Conversion and Column Self-Calibration Technique for Low Noise CMOS Image Sensors

    Directory of Open Access Journals (Sweden)

    Jaeyoung Bae

    2014-07-01

    Full Text Available In this paper, a 120 frames per second (fps low noise CMOS Image Sensor (CIS based on a Two-Step Single Slope ADC (TS SS ADC and column self-calibration technique is proposed. The TS SS ADC is suitable for high speed video systems because its conversion speed is much faster (by more than 10 times than that of the Single Slope ADC (SS ADC. However, there exist some mismatching errors between the coarse block and the fine block due to the 2-step operation of the TS SS ADC. In general, this makes it difficult to implement the TS SS ADC beyond a 10-bit resolution. In order to improve such errors, a new 4-input comparator is discussed and a high resolution TS SS ADC is proposed. Further, a feedback circuit that enables column self-calibration to reduce the Fixed Pattern Noise (FPN is also described. The proposed chip has been fabricated with 0.13 μm Samsung CIS technology and the chip satisfies the VGA resolution. The pixel is based on the 4-TR Active Pixel Sensor (APS. The high frame rate of 120 fps is achieved at the VGA resolution. The measured FPN is 0.38 LSB, and measured dynamic range is about 64.6 dB.

  15. Pithy Review on Routing Protocols in Wireless Sensor Networks and Least Routing Time Opportunistic Technique in WSN

    Science.gov (United States)

    Salman Arafath, Mohammed; Rahman Khan, Khaleel Ur; Sunitha, K. V. N.

    2018-01-01

    Nowadays due to most of the telecommunication standard development organizations focusing on using device-to-device communication so that they can provide proximity-based services and add-on services on top of the available cellular infrastructure. An Oppnets and wireless sensor network play a prominent role here. Routing in these networks plays a significant role in fields such as traffic management, packet delivery etc. Routing is a prodigious research area with diverse unresolved issues. This paper firstly focuses on the importance of Opportunistic routing and its concept then focus is shifted to prime aspect i.e. on packet reception ratio which is one of the highest QoS Awareness parameters. This paper discusses the two important functions of routing in wireless sensor networks (WSN) namely route selection using least routing time algorithm (LRTA) and data forwarding using clustering technique. Finally, the simulation result reveals that LRTA performs relatively better than the existing system in terms of average packet reception ratio and connectivity.

  16. Power-Management Techniques for Wireless Sensor Networks and Similar Low-Power Communication Devices Based on Nonrechargeable Batteries

    Directory of Open Access Journals (Sweden)

    Agnelo Silva

    2012-01-01

    Full Text Available Despite the well-known advantages of communication solutions based on energy harvesting, there are scenarios where the absence of batteries (supercapacitor only or the use of rechargeable batteries is not a realistic option. Therefore, the alternative is to extend as much as possible the lifetime of primary cells (nonrechargeable batteries. By assuming low duty-cycle applications, three power-management techniques are combined in a novel way to provide an efficient energy solution for wireless sensor networks nodes or similar communication devices powered by primary cells. Accordingly, a customized node is designed and long-term experiments in laboratory and outdoors are realized. Simulated and empirical results show that the battery lifetime can be drastically enhanced. However, two trade-offs are identified: a significant increase of both data latency and hardware/software complexity. Unattended nodes deployed in outdoors under extreme temperatures, buried sensors (underground communication, and nodes embedded in the structure of buildings, bridges, and roads are some of the target scenarios for this work. Part of the provided guidelines can be used to extend the battery lifetime of communication devices in general.

  17. Vapor Measurement System of Essential Oil Based on MOS Gas Sensors Driven with Advanced Temperature Modulation Technique

    Science.gov (United States)

    Sudarmaji, A.; Margiwiyatno, A.; Ediati, R.; Mustofa, A.

    2018-05-01

    The aroma/vapor of essential oils is complex compound which depends on the content of the gases and volatiles generated from essential oil. This paper describes a design of quick, simple, and low-cost static measurement system to acquire vapor profile of essential oil. The gases and volatiles are captured in a chamber by means of 9 MOS gas sensors which driven with advance temperature modulation technique. A PSoC CY8C28445-24PVXI based-interface unit is built to generate the modulation signal and acquire all sensor output into computer wirelessly via radio frequency serial communication using Digi International Inc., XBee (IEEE 802.15.4) through developed software under Visual.Net. The system was tested to measure 2 kinds of essential oil (Patchouli and Clove Oils) in 4 temperature modulations (without, 0.25 Hz, 1 Hz, and 4 Hz). A cycle measurement consists of reference and sample measurement sequentially which is set during 2 minutes in every 1 second respectively. It is found that the suitable modulation is 0,25Hz; 75%, and the results of Principle Component Analysis show that the system is able to distinguish clearly between Patchouli Oil and Clove Oil.

  18. A Novel Evidence Theory and Fuzzy Preference Approach-Based Multi-Sensor Data Fusion Technique for Fault Diagnosis

    Directory of Open Access Journals (Sweden)

    Fuyuan Xiao

    2017-10-01

    Full Text Available The multi-sensor data fusion technique plays a significant role in fault diagnosis and in a variety of such applications, and the Dempster–Shafer evidence theory is employed to improve the system performance; whereas, it may generate a counter-intuitive result when the pieces of evidence highly conflict with each other. To handle this problem, a novel multi-sensor data fusion approach on the basis of the distance of evidence, belief entropy and fuzzy preference relation analysis is proposed. A function of evidence distance is first leveraged to measure the conflict degree among the pieces of evidence; thus, the support degree can be obtained to represent the reliability of the evidence. Next, the uncertainty of each piece of evidence is measured by means of the belief entropy. Based on the quantitative uncertainty measured above, the fuzzy preference relations are applied to represent the relative credibility preference of the evidence. Afterwards, the support degree of each piece of evidence is adjusted by taking advantage of the relative credibility preference of the evidence that can be utilized to generate an appropriate weight with respect to each piece of evidence. Finally, the modified weights of the evidence are adopted to adjust the bodies of the evidence in the advance of utilizing Dempster’s combination rule. A numerical example and a practical application in fault diagnosis are used as illustrations to demonstrate that the proposal is reasonable and efficient in the management of conflict and fault diagnosis.

  19. On Designing Thermal-Aware Localized QoS Routing Protocol for in-vivo Sensor Nodes in Wireless Body Area Networks

    OpenAIRE

    Monowar, Muhammad Mostafa; Bajaber, Fuad

    2015-01-01

    In this paper, we address the thermal rise and Quality-of-Service (QoS) provisioning issue for an intra-body Wireless Body Area Network (WBAN) having in-vivo sensor nodes. We propose a thermal-aware QoS routing protocol, called TLQoS, that facilitates the system in achieving desired QoS in terms of delay and reliability for diverse traffic types, as well as avoids the formation of highly heated nodes known as hotspot(s), and keeps the temperature rise along the network to an acceptable level....

  20. A IR-Femtosecond Laser Hybrid Sensor to Measure the Thermal Expansion and Thermo-Optical Coefficient of Silica-Based FBG at High Temperatures.

    Science.gov (United States)

    Li, Litong; Lv, Dajuan; Yang, Minghong; Xiong, Liangming; Luo, Jie

    2018-01-26

    In this paper, a hybrid sensor was fabricated using a IR-femtosecond laser to measure the thermal expansion and thermo-optical coefficient of silica-based fiber Bragg gratings (FBGs). The hybrid sensor was composed of an inline fiber Fabry-Perot interferometer (FFPI) cavity and a type-II FBG. Experiment results showed that the type-II FBG had three high reflectivity resonances in the wavelength ranging from 1100 to 1600 nm, showing the peaks in 1.1, 1.3 and 1.5 μm, respectively. The thermal expansion and thermo-optical coefficient (1.3 μm, 1.5 μm) of silica-based FBG, under temperatures ranging from 30 to 1100 °C, had been simultaneously calculated by measuring the wavelength of the type-II FBG and FFPI cavity length.