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Sample records for accurate temperature control

  1. Development of an Accurate Feed-Forward Temperature Control Tankless Water Heater

    SciTech Connect

    David Yuill

    2008-06-30

    The following document is the final report for DE-FC26-05NT42327: Development of an Accurate Feed-Forward Temperature Control Tankless Water Heater. This work was carried out under a cooperative agreement from the Department of Energy's National Energy Technology Laboratory, with additional funding from Keltech, Inc. The objective of the project was to improve the temperature control performance of an electric tankless water heater (TWH). The reason for doing this is to minimize or eliminate one of the barriers to wider adoption of the TWH. TWH use less energy than typical (storage) water heaters because of the elimination of standby losses, so wider adoption will lead to reduced energy consumption. The project was carried out by Building Solutions, Inc. (BSI), a small business based in Omaha, Nebraska. BSI partnered with Keltech, Inc., a manufacturer of electric tankless water heaters based in Delton, Michigan. Additional work was carried out by the University of Nebraska and Mike Coward. A background study revealed several advantages and disadvantages to TWH. Besides using less energy than storage heaters, TWH provide an endless supply of hot water, have a longer life, use less floor space, can be used at point-of-use, and are suitable as boosters to enable alternative water heating technologies, such as solar or heat-pump water heaters. Their disadvantages are their higher cost, large instantaneous power requirement, and poor temperature control. A test method was developed to quantify performance under a representative range of disturbances to flow rate and inlet temperature. A device capable of conducting this test was designed and built. Some heaters currently on the market were tested, and were found to perform quite poorly. A new controller was designed using model predictive control (MPC). This control method required an accurate dynamic model to be created and required significant tuning to the controller before good control was achieved. The MPC design

  2. Accurate measurement of unsteady state fluid temperature

    NASA Astrophysics Data System (ADS)

    Jaremkiewicz, Magdalena

    2017-03-01

    In this paper, two accurate methods for determining the transient fluid temperature were presented. Measurements were conducted for boiling water since its temperature is known. At the beginning the thermometers are at the ambient temperature and next they are immediately immersed into saturated water. The measurements were carried out with two thermometers of different construction but with the same housing outer diameter equal to 15 mm. One of them is a K-type industrial thermometer widely available commercially. The temperature indicated by the thermometer was corrected considering the thermometers as the first or second order inertia devices. The new design of a thermometer was proposed and also used to measure the temperature of boiling water. Its characteristic feature is a cylinder-shaped housing with the sheath thermocouple located in its center. The temperature of the fluid was determined based on measurements taken in the axis of the solid cylindrical element (housing) using the inverse space marching method. Measurements of the transient temperature of the air flowing through the wind tunnel using the same thermometers were also carried out. The proposed measurement technique provides more accurate results compared with measurements using industrial thermometers in conjunction with simple temperature correction using the inertial thermometer model of the first or second order. By comparing the results, it was demonstrated that the new thermometer allows obtaining the fluid temperature much faster and with higher accuracy in comparison to the industrial thermometer. Accurate measurements of the fast changing fluid temperature are possible due to the low inertia thermometer and fast space marching method applied for solving the inverse heat conduction problem.

  3. Apparatus for accurately measuring high temperatures

    DOEpatents

    Smith, D.D.

    The present invention is a thermometer used for measuring furnace temperatures in the range of about 1800/sup 0/ to 2700/sup 0/C. The thermometer comprises a broadband multicolor thermal radiation sensor positioned to be in optical alignment with the end of a blackbody sight tube extending into the furnace. A valve-shutter arrangement is positioned between the radiation sensor and the sight tube and a chamber for containing a charge of high pressure gas is positioned between the valve-shutter arrangement and the radiation sensor. A momentary opening of the valve shutter arrangement allows a pulse of the high gas to purge the sight tube of air-borne thermal radiation contaminants which permits the radiation sensor to accurately measure the thermal radiation emanating from the end of the sight tube.

  4. Accurate method for computing correlated color temperature.

    PubMed

    Li, Changjun; Cui, Guihua; Melgosa, Manuel; Ruan, Xiukai; Zhang, Yaoju; Ma, Long; Xiao, Kaida; Luo, M Ronnier

    2016-06-27

    For the correlated color temperature (CCT) of a light source to be estimated, a nonlinear optimization problem must be solved. In all previous methods available to compute CCT, the objective function has only been approximated, and their predictions have achieved limited accuracy. For example, different unacceptable CCT values have been predicted for light sources located on the same isotemperature line. In this paper, we propose to compute CCT using the Newton method, which requires the first and second derivatives of the objective function. Following the current recommendation by the International Commission on Illumination (CIE) for the computation of tristimulus values (summations at 1 nm steps from 360 nm to 830 nm), the objective function and its first and second derivatives are explicitly given and used in our computations. Comprehensive tests demonstrate that the proposed method, together with an initial estimation of CCT using Robertson's method [J. Opt. Soc. Am. 58, 1528-1535 (1968)], gives highly accurate predictions below 0.0012 K for light sources with CCTs ranging from 500 K to 106 K.

  5. Apparatus for accurately measuring high temperatures

    DOEpatents

    Smith, Douglas D.

    1985-01-01

    The present invention is a thermometer used for measuring furnace temperaes in the range of about 1800.degree. to 2700.degree. C. The thermometer comprises a broadband multicolor thermal radiation sensor positioned to be in optical alignment with the end of a blackbody sight tube extending into the furnace. A valve-shutter arrangement is positioned between the radiation sensor and the sight tube and a chamber for containing a charge of high pressure gas is positioned between the valve-shutter arrangement and the radiation sensor. A momentary opening of the valve shutter arrangement allows a pulse of the high gas to purge the sight tube of air-borne thermal radiation contaminants which permits the radiation sensor to accurately measure the thermal radiation emanating from the end of the sight tube.

  6. Does forehead liquid crystal temperature accurately reflect "core" temperature?

    PubMed

    Allen, G C; Horrow, J C; Rosenberg, H

    1990-09-01

    Liquid crystal thermometry (LCT) is a non-invasive alternative to temperature monitoring. We evaluated the ability of forehead LCT, rectal temperature, and axillary skin temperature to trend distal oesophageal temperature during rapid warming on cardiopulmonary bypass. In 24 patients undergoing open heart surgery, temperatures were measured during the rapid warming phase on bypass (12-35 min). Scattergrams of temperature vs time for the four temperature sites each contained 150 data points. Polynomial regression analysis revealed that LCT, but not axillary or rectal temperatures, correlated with oesophageal temperature. We conclude that forehead LCT may be useful to monitor temperature trends and to detect rapid elevations in body temperature when more invasive temperature monitoring is inappropriate or unavailable.

  7. An Accurate Temperature Correction Model for Thermocouple Hygrometers 1

    PubMed Central

    Savage, Michael J.; Cass, Alfred; de Jager, James M.

    1982-01-01

    Numerous water relation studies have used thermocouple hygrometers routinely. However, the accurate temperature correction of hygrometer calibration curve slopes seems to have been largely neglected in both psychrometric and dewpoint techniques. In the case of thermocouple psychrometers, two temperature correction models are proposed, each based on measurement of the thermojunction radius and calculation of the theoretical voltage sensitivity to changes in water potential. The first model relies on calibration at a single temperature and the second at two temperatures. Both these models were more accurate than the temperature correction models currently in use for four psychrometers calibrated over a range of temperatures (15-38°C). The model based on calibration at two temperatures is superior to that based on only one calibration. The model proposed for dewpoint hygrometers is similar to that for psychrometers. It is based on the theoretical voltage sensitivity to changes in water potential. Comparison with empirical data from three dewpoint hygrometers calibrated at four different temperatures indicates that these instruments need only be calibrated at, e.g. 25°C, if the calibration slopes are corrected for temperature. PMID:16662241

  8. An accurate temperature correction model for thermocouple hygrometers.

    PubMed

    Savage, M J; Cass, A; de Jager, J M

    1982-02-01

    Numerous water relation studies have used thermocouple hygrometers routinely. However, the accurate temperature correction of hygrometer calibration curve slopes seems to have been largely neglected in both psychrometric and dewpoint techniques.In the case of thermocouple psychrometers, two temperature correction models are proposed, each based on measurement of the thermojunction radius and calculation of the theoretical voltage sensitivity to changes in water potential. The first model relies on calibration at a single temperature and the second at two temperatures. Both these models were more accurate than the temperature correction models currently in use for four psychrometers calibrated over a range of temperatures (15-38 degrees C). The model based on calibration at two temperatures is superior to that based on only one calibration.The model proposed for dewpoint hygrometers is similar to that for psychrometers. It is based on the theoretical voltage sensitivity to changes in water potential. Comparison with empirical data from three dewpoint hygrometers calibrated at four different temperatures indicates that these instruments need only be calibrated at, e.g. 25 degrees C, if the calibration slopes are corrected for temperature.

  9. Instrument accurately measures small temperature changes on test surface

    NASA Technical Reports Server (NTRS)

    Harvey, W. D.; Miller, H. B.

    1966-01-01

    Calorimeter apparatus accurately measures very small temperature rises on a test surface subjected to aerodynamic heating. A continuous thin sheet of a sensing material is attached to a base support plate through which a series of holes of known diameter have been drilled for attaching thermocouples to the material.

  10. Method for Accurate Surface Temperature Measurements During Fast Induction Heating

    NASA Astrophysics Data System (ADS)

    Larregain, Benjamin; Vanderesse, Nicolas; Bridier, Florent; Bocher, Philippe; Arkinson, Patrick

    2013-07-01

    A robust method is proposed for the measurement of surface temperature fields during induction heating. It is based on the original coupling of temperature-indicating lacquers and a high-speed camera system. Image analysis tools have been implemented to automatically extract the temporal evolution of isotherms. This method was applied to the fast induction treatment of a 4340 steel spur gear, allowing the full history of surface isotherms to be accurately documented for a sequential heating, i.e., a medium frequency preheating followed by a high frequency final heating. Three isotherms, i.e., 704, 816, and 927°C, were acquired every 0.3 ms with a spatial resolution of 0.04 mm per pixel. The information provided by the method is described and discussed. Finally, the transformation temperature Ac1 is linked to the temperature on specific locations of the gear tooth.

  11. Cooled, temperature controlled electrometer

    DOEpatents

    Morgan, John P.

    1992-08-04

    A cooled, temperature controlled electrometer for the measurement of small currents. The device employs a thermal transfer system to remove heat from the electrometer circuit and its environment and dissipate it to the external environment by means of a heat sink. The operation of the thermal transfer system is governed by a temperature regulation circuit which activates the thermal transfer system when the temperature of the electrometer circuit and its environment exceeds a level previously inputted to the external variable temperature control circuit. The variable temperature control circuit functions as subpart of the temperature control circuit. To provide temperature stability and uniformity, the electrometer circuit is enclosed by an insulated housing.

  12. Cooled, temperature controlled electrometer

    DOEpatents

    Morgan, John P.

    1992-01-01

    A cooled, temperature controlled electrometer for the measurement of small currents. The device employs a thermal transfer system to remove heat from the electrometer circuit and its environment and dissipate it to the external environment by means of a heat sink. The operation of the thermal transfer system is governed by a temperature regulation circuit which activates the thermal transfer system when the temperature of the electrometer circuit and its environment exceeds a level previously inputted to the external variable temperature control circuit. The variable temperature control circuit functions as subpart of the temperature control circuit. To provide temperature stability and uniformity, the electrometer circuit is enclosed by an insulated housing.

  13. Controlling Hay Fever Symptoms with Accurate Pollen Counts

    MedlinePlus

    ... Library ▸ Hay fever and pollen counts Share | Controlling Hay Fever Symptoms with Accurate Pollen Counts This article has ... Pongdee, MD, FAAAAI Seasonal allergic rhinitis known as hay fever is caused by pollen carried in the air ...

  14. Digital system accurately controls velocity of electromechanical drive

    NASA Technical Reports Server (NTRS)

    Nichols, G. B.

    1965-01-01

    Digital circuit accurately regulates electromechanical drive mechanism velocity. The gain and phase characteristics of digital circuits are relatively unimportant. Control accuracy depends only on the stability of the input signal frequency.

  15. Liquid crystal skin thermometry: an accurate reflection of core temperature?

    PubMed

    Brull, S J; Cunningham, A J; Connelly, N R; O'Connor, T Z; Silverman, D G

    1993-04-01

    Oesophageal, rectal, bladder, tympanic and pulmonary artery sites are used intraoperatively to measure body temperature. However, the temperatures measured at each site have different physiological and practical importance. The present two-part study sought to compare liquid crystal (CR) skin temperature with other temperature monitors which are used routinely during surgery. The first part compared CR with oesophageal (OS) temperature during general inhalational anaesthesia. The second part compared CR with OS, pulmonary artery (PA), and bladder (BL) temperatures during the periods of rapid temperature change associated with cardiopulmonary bypass (CPB). During the first part, the mean difference between OS and CR was -0.14 +/- 0.85 degrees C; this difference remained consistent over time (P < 0.05 by repeated measures analysis of variance). During the second part, the difference in temperature readings between CR and each of the other monitors remained consistent except for CR vs PA and CR vs OS during the cooling period of CPB, when the iced cardioplegia slush directly affected the PA and OS temperatures. This study suggests that CR, an inexpensive and noninvasive means of temperature monitoring, reflects trends in temperature changes in the clinical setting.

  16. Platinum thin film resistors as accurate and stable temperature sensors

    NASA Technical Reports Server (NTRS)

    Diehl, W.

    1984-01-01

    The measurement characteristics of thin-Pt-film temperature sensors fabricated using advanced methods are discussed. The limitations of wound-wire Pt temperature sensors and the history of Pt-film development are outlined, and the commonly used film-deposition, structuring, and trimming methods are presented in a table. The development of a family of sputtered film resistors is described in detail and illustrated with photographs of the different types. The most commonly used tolerances are reported as + or - 0.3 C + 0.5 percent of the temperature measured.

  17. Diamond micro-Raman thermometers for accurate gate temperature measurements

    SciTech Connect

    Simon, Roland B.; Pomeroy, James W.; Kuball, Martin

    2014-05-26

    Determining the peak channel temperature in AlGaN/GaN high electron mobility transistors and other devices with high accuracy is an important and challenging issue. A surface-sensitive thermometric technique is demonstrated, utilizing Raman thermography and diamond microparticles to measure the gate temperature. This technique enhances peak channel temperature estimation, especially when it is applied in combination with standard micro-Raman thermography. Its application to other metal-covered areas of devices, such as field plates is demonstrated. Furthermore, this technique can be readily applied to other material/device systems.

  18. ACCURATE TEMPERATURE MEASUREMENTS IN A NATURALLY-ASPIRATED RADIATION SHIELD

    SciTech Connect

    Kurzeja, R.

    2009-09-09

    Experiments and calculations were conducted with a 0.13 mm fine wire thermocouple within a naturally-aspirated Gill radiation shield to assess and improve the accuracy of air temperature measurements without the use of mechanical aspiration, wind speed or radiation measurements. It was found that this thermocouple measured the air temperature with root-mean-square errors of 0.35 K within the Gill shield without correction. A linear temperature correction was evaluated based on the difference between the interior plate and thermocouple temperatures. This correction was found to be relatively insensitive to shield design and yielded an error of 0.16 K for combined day and night observations. The correction was reliable in the daytime when the wind speed usually exceeds 1 m s{sup -1} but occasionally performed poorly at night during very light winds. Inspection of the standard deviation in the thermocouple wire temperature identified these periods but did not unambiguously locate the most serious events. However, estimates of sensor accuracy during these periods is complicated by the much larger sampling volume of the mechanically-aspirated sensor compared with the naturally-aspirated sensor and the presence of significant near surface temperature gradients. The root-mean-square errors therefore are upper limits to the aspiration error since they include intrinsic sensor differences and intermittent volume sampling differences.

  19. Temperature-Controlling Circuit

    NASA Technical Reports Server (NTRS)

    Temple, Gerald

    1987-01-01

    Simple circuit switches current to electrical heater on and off to maintain temperature of room at 25 plus or minus 0.5 degree C. Lightweight, compact, reliable, insensitive to electrical noise, and uses single 5-Vdc power supply. Handles ac loads of 10 A. Designed to operate outside temperature controlled environment over range of -55 to +85 degree C. Thermistor provides input signal for simple temperature controller. Output of controller applied to solid-state relay, which in turn switches current to resistance heater.

  20. Accurate estimation of cardinal growth temperatures of Escherichia coli from optimal dynamic experiments.

    PubMed

    Van Derlinden, E; Bernaerts, K; Van Impe, J F

    2008-11-30

    Prediction of the microbial growth rate as a response to changing temperatures is an important aspect in the control of food safety and food spoilage. Accurate model predictions of the microbial evolution ask for correct model structures and reliable parameter values with good statistical quality. Given the widely accepted validity of the Cardinal Temperature Model with Inflection (CTMI) [Rosso, L., Lobry, J. R., Bajard, S. and Flandrois, J. P., 1995. Convenient model to describe the combined effects of temperature and pH on microbial growth, Applied and Environmental Microbiology, 61: 610-616], this paper focuses on the accurate estimation of its four parameters (T(min), T(opt), T(max) and micro(opt)) by applying the technique of optimal experiment design for parameter estimation (OED/PE). This secondary model describes the influence of temperature on the microbial specific growth rate from the minimum to the maximum temperature for growth. Dynamic temperature profiles are optimized within two temperature regions ([15 degrees C, 43 degrees C] and [15 degrees C, 45 degrees C]), focusing on the minimization of the parameter estimation (co)variance (D-optimal design). The optimal temperature profiles are implemented in a computer controlled bioreactor, and the CTMI parameters are identified from the resulting experimental data. Approximately equal CTMI parameter values were derived irrespective of the temperature region, except for T(max). The latter could only be estimated accurately from the optimal experiments within [15 degrees C, 45 degrees C]. This observation underlines the importance of selecting the upper temperature constraint for OED/PE as close as possible to the true T(max). Cardinal temperature estimates resulting from designs within [15 degrees C, 45 degrees C] correspond with values found in literature, are characterized by a small uncertainty error and yield a good result during validation. As compared to estimates from non-optimized dynamic

  1. Dynamical correction of control laws for marine ships' accurate steering

    NASA Astrophysics Data System (ADS)

    Veremey, Evgeny I.

    2014-06-01

    The objective of this work is the analytical synthesis problem for marine vehicles autopilots design. Despite numerous known methods for a solution, the mentioned problem is very complicated due to the presence of an extensive population of certain dynamical conditions, requirements and restrictions, which must be satisfied by the appropriate choice of a steering control law. The aim of this paper is to simplify the procedure of the synthesis, providing accurate steering with desirable dynamics of the control system. The approach proposed here is based on the usage of a special unified multipurpose control law structure that allows decoupling a synthesis into simpler particular optimization problems. In particular, this structure includes a dynamical corrector to support the desirable features for the vehicle's motion under the action of sea wave disturbances. As a result, a specialized new method for the corrector design is proposed to provide an accurate steering or a trade-off between accurate steering and economical steering of the ship. This method guaranties a certain flexibility of the control law with respect to an actual environment of the sailing; its corresponding turning can be realized in real time onboard.

  2. Accurate, reliable control of process gases by mass flow controllers

    SciTech Connect

    Hardy, J.; McKnight, T.

    1997-02-01

    The thermal mass flow controller, or MFC, has become an instrument of choice for the monitoring and controlling of process gas flow throughout the materials processing industry. These MFCs are used on CVD processes, etching tools, and furnaces and, within the semiconductor industry, are used on 70% of the processing tools. Reliability and accuracy are major concerns for the users of the MFCs. Calibration and characterization technologies for the development and implementation of mass flow devices are described. A test facility is available to industry and universities to test and develop gas floe sensors and controllers and evaluate their performance related to environmental effects, reliability, reproducibility, and accuracy. Additional work has been conducted in the area of accuracy. A gravimetric calibrator was invented that allows flow sensors to be calibrated in corrosive, reactive gases to an accuracy of 0.3% of reading, at least an order of magnitude better than previously possible. Although MFCs are typically specified with accuracies of 1% of full scale, MFCs may often be implemented with unwarranted confidence due to the conventional use of surrogate gas factors. Surrogate gas factors are corrections applied to process flow indications when an MFC has been calibrated on a laboratory-safe surrogate gas, but is actually used on a toxic, or corrosive process gas. Previous studies have indicated that the use of these factors may cause process flow errors of typically 10%, but possibly as great as 40% of full scale. This paper will present possible sources of error in MFC process gas flow monitoring and control, and will present an overview of corrective measures which may be implemented with MFC use to significantly reduce these sources of error.

  3. Fast and Accurate Prediction of Stratified Steel Temperature During Holding Period of Ladle

    NASA Astrophysics Data System (ADS)

    Deodhar, Anirudh; Singh, Umesh; Shukla, Rishabh; Gautham, B. P.; Singh, Amarendra K.

    2017-04-01

    Thermal stratification of liquid steel in a ladle during the holding period and the teeming operation has a direct bearing on the superheat available at the caster and hence on the caster set points such as casting speed and cooling rates. The changes in the caster set points are typically carried out based on temperature measurements at the end of tundish outlet. Thermal prediction models provide advance knowledge of the influence of process and design parameters on the steel temperature at various stages. Therefore, they can be used in making accurate decisions about the caster set points in real time. However, this requires both fast and accurate thermal prediction models. In this work, we develop a surrogate model for the prediction of thermal stratification using data extracted from a set of computational fluid dynamics (CFD) simulations, pre-determined using design of experiments technique. Regression method is used for training the predictor. The model predicts the stratified temperature profile instantaneously, for a given set of process parameters such as initial steel temperature, refractory heat content, slag thickness, and holding time. More than 96 pct of the predicted values are within an error range of ±5 K (±5 °C), when compared against corresponding CFD results. Considering its accuracy and computational efficiency, the model can be extended for thermal control of casting operations. This work also sets a benchmark for developing similar thermal models for downstream processes such as tundish and caster.

  4. Fast and Accurate Prediction of Stratified Steel Temperature During Holding Period of Ladle

    NASA Astrophysics Data System (ADS)

    Deodhar, Anirudh; Singh, Umesh; Shukla, Rishabh; Gautham, B. P.; Singh, Amarendra K.

    2016-12-01

    Thermal stratification of liquid steel in a ladle during the holding period and the teeming operation has a direct bearing on the superheat available at the caster and hence on the caster set points such as casting speed and cooling rates. The changes in the caster set points are typically carried out based on temperature measurements at the end of tundish outlet. Thermal prediction models provide advance knowledge of the influence of process and design parameters on the steel temperature at various stages. Therefore, they can be used in making accurate decisions about the caster set points in real time. However, this requires both fast and accurate thermal prediction models. In this work, we develop a surrogate model for the prediction of thermal stratification using data extracted from a set of computational fluid dynamics (CFD) simulations, pre-determined using design of experiments technique. Regression method is used for training the predictor. The model predicts the stratified temperature profile instantaneously, for a given set of process parameters such as initial steel temperature, refractory heat content, slag thickness, and holding time. More than 96 pct of the predicted values are within an error range of ±5 K (±5 °C), when compared against corresponding CFD results. Considering its accuracy and computational efficiency, the model can be extended for thermal control of casting operations. This work also sets a benchmark for developing similar thermal models for downstream processes such as tundish and caster.

  5. Methods for accurate cold-chain temperature monitoring using digital data-logger thermometers

    NASA Astrophysics Data System (ADS)

    Chojnacky, M. J.; Miller, W. M.; Strouse, G. F.

    2013-09-01

    Complete and accurate records of vaccine temperature history are vital to preserving drug potency and patient safety. However, previously published vaccine storage and handling guidelines have failed to indicate a need for continuous temperature monitoring in vaccine storage refrigerators. We evaluated the performance of seven digital data logger models as candidates for continuous temperature monitoring of refrigerated vaccines, based on the following criteria: out-of-box performance and compliance with manufacturer accuracy specifications over the range of use; measurement stability over extended, continuous use; proper setup in a vaccine storage refrigerator so that measurements reflect liquid vaccine temperatures; and practical methods for end-user validation and establishing metrological traceability. Data loggers were tested using ice melting point checks and by comparison to calibrated thermocouples to characterize performance over 0 °C to 10 °C. We also monitored logger performance in a study designed to replicate the range of vaccine storage and environmental conditions encountered at provider offices. Based on the results of this study, the Centers for Disease Control released new guidelines on proper methods for storage, handling, and temperature monitoring of vaccines for participants in its federally-funded Vaccines for Children Program. Improved temperature monitoring practices will ultimately decrease waste from damaged vaccines, improve consumer confidence, and increase effective inoculation rates.

  6. Quality metric for accurate overlay control in <20nm nodes

    NASA Astrophysics Data System (ADS)

    Klein, Dana; Amit, Eran; Cohen, Guy; Amir, Nuriel; Har-Zvi, Michael; Huang, Chin-Chou Kevin; Karur-Shanmugam, Ramkumar; Pierson, Bill; Kato, Cindy; Kurita, Hiroyuki

    2013-04-01

    The semiconductor industry is moving toward 20nm nodes and below. As the Overlay (OVL) budget is getting tighter at these advanced nodes, the importance in the accuracy in each nanometer of OVL error is critical. When process owners select OVL targets and methods for their process, they must do it wisely; otherwise the reported OVL could be inaccurate, resulting in yield loss. The same problem can occur when the target sampling map is chosen incorrectly, consisting of asymmetric targets that will cause biased correctable terms and a corrupted wafer. Total measurement uncertainty (TMU) is the main parameter that process owners use when choosing an OVL target per layer. Going towards the 20nm nodes and below, TMU will not be enough for accurate OVL control. KLA-Tencor has introduced a quality score named `Qmerit' for its imaging based OVL (IBO) targets, which is obtained on the-fly for each OVL measurement point in X & Y. This Qmerit score will enable the process owners to select compatible targets which provide accurate OVL values for their process and thereby improve their yield. Together with K-T Analyzer's ability to detect the symmetric targets across the wafer and within the field, the Archer tools will continue to provide an independent, reliable measurement of OVL error into the next advanced nodes, enabling fabs to manufacture devices that meet their tight OVL error budgets.

  7. Thermionic Converter Temperature Controller

    SciTech Connect

    Shaner,B. J.; Wolf, Joseph H.; Johnson, Robert G. R.

    1999-08-23

    A method and apparatus for controlling the temperature of a thermionic reactor over a wide range of operating power, including a thermionic reactor having a plurality of integral cesium reservoirs, a honeycomb material disposed about the reactor which has a plurality of separated cavities, a solid sheath disposed about the honeycomb material and having an opening therein communicating with the honeycomb material and cavities thereof, and a shell disposed about the sheath for creating a coolant annulus therewith so that the coolant in the annulus may fill the cavities and permit nucleate boiling during the operation of the reactor.

  8. Thermionic converter temperature controller

    DOEpatents

    Shaner, Benjamin J.; Wolf, Joseph H.; Johnson, Robert G. R.

    2001-04-24

    A method and apparatus for controlling the temperature of a thermionic reactor over a wide range of operating power, including a thermionic reactor having a plurality of integral cesium reservoirs, a honeycomb material disposed about the reactor which has a plurality of separated cavities, a solid sheath disposed about the honeycomb material and having an opening therein communicating with the honeycomb material and cavities thereof, and a shell disposed about the sheath for creating a coolant annulus therewith so that the coolant in the annulus may fill the cavities and permit nucleate boiling during the operation of the reactor.

  9. Temperature-feedback upconversion nanocomposite for accurate photothermal therapy at facile temperature.

    PubMed

    Zhu, Xingjun; Feng, Wei; Chang, Jian; Tan, Yan-Wen; Li, Jiachang; Chen, Min; Sun, Yun; Li, Fuyou

    2016-02-04

    Photothermal therapy (PTT) at present, following the temperature definition for conventional thermal therapy, usually keeps the temperature of lesions at 42-45 °C or even higher. Such high temperature kills cancer cells but also increases the damage of normal tissues near lesions through heat conduction and thus brings about more side effects and inhibits therapeutic accuracy. Here we use temperature-feedback upconversion nanoparticle combined with photothermal material for real-time monitoring of microscopic temperature in PTT. We observe that microscopic temperature of photothermal material upon illumination is high enough to kill cancer cells when the temperature of lesions is still low enough to prevent damage to normal tissue. On the basis of the above phenomenon, we further realize high spatial resolution photothermal ablation of labelled tumour with minimal damage to normal tissues in vivo. Our work points to a method for investigating photothermal properties at nanoscale, and for the development of new generation of PTT strategy.

  10. Temperature-feedback upconversion nanocomposite for accurate photothermal therapy at facile temperature

    NASA Astrophysics Data System (ADS)

    Zhu, Xingjun; Feng, Wei; Chang, Jian; Tan, Yan-Wen; Li, Jiachang; Chen, Min; Sun, Yun; Li, Fuyou

    2016-02-01

    Photothermal therapy (PTT) at present, following the temperature definition for conventional thermal therapy, usually keeps the temperature of lesions at 42-45 °C or even higher. Such high temperature kills cancer cells but also increases the damage of normal tissues near lesions through heat conduction and thus brings about more side effects and inhibits therapeutic accuracy. Here we use temperature-feedback upconversion nanoparticle combined with photothermal material for real-time monitoring of microscopic temperature in PTT. We observe that microscopic temperature of photothermal material upon illumination is high enough to kill cancer cells when the temperature of lesions is still low enough to prevent damage to normal tissue. On the basis of the above phenomenon, we further realize high spatial resolution photothermal ablation of labelled tumour with minimal damage to normal tissues in vivo. Our work points to a method for investigating photothermal properties at nanoscale, and for the development of new generation of PTT strategy.

  11. Test system accurately determines tensile properties of irradiated metals at cryogenic temperatures

    NASA Technical Reports Server (NTRS)

    Levine, P. J.; Skalka, R. J.; Vandergrift, E. F.

    1967-01-01

    Modified testing system determines tensile properties of irradiated brittle-type metals at cryogenic temperatures. The system includes a lightweight cryostat, split-screw grips, a universal joint, and a special temperature control system.

  12. Temperature-feedback upconversion nanocomposite for accurate photothermal therapy at facile temperature

    PubMed Central

    Zhu, Xingjun; Feng, Wei; Chang, Jian; Tan, Yan-Wen; Li, Jiachang; Chen, Min; Sun, Yun; Li, Fuyou

    2016-01-01

    Photothermal therapy (PTT) at present, following the temperature definition for conventional thermal therapy, usually keeps the temperature of lesions at 42–45 °C or even higher. Such high temperature kills cancer cells but also increases the damage of normal tissues near lesions through heat conduction and thus brings about more side effects and inhibits therapeutic accuracy. Here we use temperature-feedback upconversion nanoparticle combined with photothermal material for real-time monitoring of microscopic temperature in PTT. We observe that microscopic temperature of photothermal material upon illumination is high enough to kill cancer cells when the temperature of lesions is still low enough to prevent damage to normal tissue. On the basis of the above phenomenon, we further realize high spatial resolution photothermal ablation of labelled tumour with minimal damage to normal tissues in vivo. Our work points to a method for investigating photothermal properties at nanoscale, and for the development of new generation of PTT strategy. PMID:26842674

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

    PubMed

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

    2016-08-08

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

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

    PubMed Central

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

    2016-01-01

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

  15. Air toxics being measured more accurately, controlled more effectively

    SciTech Connect

    1995-04-01

    In response to the directives of the Clean Air Act Amendments, Argonne National Laboratory is developing new or improved pollutant control technologies for industries that burn fossil fuels. This research continues Argonne`s traditional support for the US DOE Flue Gas Cleanup Program. Research is underway to measure process emissions and identify new and improved control measures. Argonne`s emission control research has ranged from experiments in the basic chemistry of pollution-control systems, through laboratory-scale process development and testing to pilot-scale field tests of several technologies. Whenever appropriate, the work has emphasized integrated or combined control systems as the best approach to technologies that offer low cost and good operating characteristics.

  16. Accurate ampacity determination: Temperature-Sag Model for operational real time ratings

    SciTech Connect

    Seppa, T.O.

    1995-07-01

    This report presents a method for determining transmission line ratings based on the relationship between the conductor`s temperature and its sag. The method is based on the Ruling Span principle and the use of transmission line tension monitoring systems. The report also presents a method of accurately calibrating the final sag of the conductor and determining the actual Ruling Span length of the line sections between deadend structures. Main error sources for two other real time methods are also examined.

  17. Accurate control of hyperbolic trajectories in any dimension.

    PubMed

    Balasuriya, Sanjeeva; Padberg-Gehle, Kathrin

    2014-09-01

    The unsteady (nonautonomous) analog of a hyperbolic fixed point is a hyperbolic trajectory, whose importance is underscored by its attached stable and unstable manifolds, which have relevance in fluid flow barriers, chaotic basin boundaries, and the long-term behavior of the system. We develop a method for obtaining the unsteady control velocity which forces a hyperbolic trajectory to follow a user-prescribed variation with time. Our method is applicable in any dimension, and accuracy to any order is achievable. We demonstrate and validate our method by (1) controlling the fixed point at the origin of the Lorenz system, for example, obtaining a user-defined nonautonomous attractor, and (2) the saddle points in a droplet flow, using localized control which generates global transport.

  18. Extracting accurate temperatures of molten basalts from non-contact thermal infrared radiance data

    NASA Astrophysics Data System (ADS)

    Fontanella, N. R.; Ramsey, M. S.; Lee, R.

    2013-12-01

    The eruptive and emplacement temperature of a lava flow relates important information on parameters such as the composition, rheology, and emplacement processes. It can also serve as a critical input into flow cooling and propagation models used for hazard prediction. One of the most common ways to determine temperatures of active lava flows is to use non-contact thermal infrared (TIR) measurements, either from ground-based radiometers and cameras or air and space-based remote sensing instruments. These temperature measurements assume a fixed value for the lava emissivity in order to solve the Planck Equation for temperature. The research presented here examines the possibility of variable emissivity in a material's molten state and the effect it has on deriving accurate surface temperature. Emplacement of a pahoehoe lava lobe at Kilauea volcano, Hawaii was captured with high spatial resolution/high frame rate TIR video in order to study this phenomenon. The data show the appearance of molten lava at a breakout point until it cools to form a glassy crust that begins to fold. Emissivity was adjusted sequentially along linear transects from a starting value of 1.0 to lower values until the TIR temperature matched the known temperature measured with a thermocouple. Below an emissivity of ~0.89, temperatures of the molten lava rose above the known lava temperature. This value suggests a decrease in emissivity with a change of state and is likely due to changes in the atomic bond structure of the melt. We have also recently completed the first ever calibrated laboratory-based emissivity measurements of molten basalts, and these high spectral resolution data confirm the field-based estimates. In contrast to rhyolites, basalts appear to display a less dramatic change between their glassy and molten spectra due to their higher melting and glass transition temperatures and the quick formation time of the crust. Therefore, the change in emissivity for molten rhyolite could

  19. Enabling quantum communications through accurate photons polarization control

    NASA Astrophysics Data System (ADS)

    Almeida, Álvaro J.; Muga, Nelson J.; Silva, Nuno A.; Stojanovic, Aleksandar D.; André, Paulo S.; Pinto, Armando N.; Mora, José; Capmany, José

    2013-11-01

    The rapid increase on the information sharing around the world, leads to an utmost requirement for capacity and bandwidth. However, the need for security in the transmission and storage of information is also of major importance. The use of quantum technologies provides a practical solution for secure communications systems. Quantum key distribution (QKD) was the first practical application of quantum mechanics, and nowadays it is the most developed one. In order to share secret keys between two parties can be used several methods of encoding. Due to its simplicity, the encoding into polarization is one of the most used. However, when we use optical fibers as transmission channels, the polarization suffers random rotations that may change the state of polarization (SOP) of the light initially sent to the fiber to a new one at the output. Thus, in order to enable real-time communication using this encoding method it is required the use of a dynamic control system. We describe a scheme of transmission of quantum information, which is based in the polarization encoding, and that allows to share secret keys through optical fibers without interruption. The dynamic polarization control system used in such scheme is described, both theoretically and experimentally. Their advantages and limitations for the use in quantum communications are presented and discussed.

  20. TG wave autoresonant control of plasma temperature

    SciTech Connect

    Kabantsev, A. A. Driscoll, C. F.

    2015-06-29

    The thermal correction term in the Trivelpiece-Gould (TG) wave’s frequency has been used to accurately control the temperature of electron plasma, by applying a swept-frequency continuous drive autoresonantly locked in balance with the cyclotron cooling. The electron temperature can be either “pegged” at a desired value (by constant drive frequency); or varied cyclically (following the tailored frequency course), with rates limited by the cooling time (on the way down) and by chosen drive amplitude (on the way up)

  1. Fast and accurate quantum molecular dynamics of dense plasmas across temperature regimes

    SciTech Connect

    Sjostrom, Travis; Daligault, Jerome

    2014-10-10

    Here, we develop and implement a new quantum molecular dynamics approximation that allows fast and accurate simulations of dense plasmas from cold to hot conditions. The method is based on a carefully designed orbital-free implementation of density functional theory. The results for hydrogen and aluminum are in very good agreement with Kohn-Sham (orbital-based) density functional theory and path integral Monte Carlo calculations for microscopic features such as the electron density as well as the equation of state. The present approach does not scale with temperature and hence extends to higher temperatures than is accessible in the Kohn-Sham method and lower temperatures than is accessible by path integral Monte Carlo calculations, while being significantly less computationally expensive than either of those two methods.

  2. Fast and accurate quantum molecular dynamics of dense plasmas across temperature regimes

    DOE PAGES

    Sjostrom, Travis; Daligault, Jerome

    2014-10-10

    Here, we develop and implement a new quantum molecular dynamics approximation that allows fast and accurate simulations of dense plasmas from cold to hot conditions. The method is based on a carefully designed orbital-free implementation of density functional theory. The results for hydrogen and aluminum are in very good agreement with Kohn-Sham (orbital-based) density functional theory and path integral Monte Carlo calculations for microscopic features such as the electron density as well as the equation of state. The present approach does not scale with temperature and hence extends to higher temperatures than is accessible in the Kohn-Sham method and lowermore » temperatures than is accessible by path integral Monte Carlo calculations, while being significantly less computationally expensive than either of those two methods.« less

  3. Central control of body temperature

    PubMed Central

    Morrison, Shaun F.

    2016-01-01

    Central neural circuits orchestrate the behavioral and autonomic repertoire that maintains body temperature during environmental temperature challenges and alters body temperature during the inflammatory response and behavioral states and in response to declining energy homeostasis. This review summarizes the central nervous system circuit mechanisms controlling the principal thermoeffectors for body temperature regulation: cutaneous vasoconstriction regulating heat loss and shivering and brown adipose tissue for thermogenesis. The activation of these thermoeffectors is regulated by parallel but distinct efferent pathways within the central nervous system that share a common peripheral thermal sensory input. The model for the neural circuit mechanism underlying central thermoregulatory control provides a useful platform for further understanding of the functional organization of central thermoregulation, for elucidating the hypothalamic circuitry and neurotransmitters involved in body temperature regulation, and for the discovery of novel therapeutic approaches to modulating body temperature and energy homeostasis. PMID:27239289

  4. System to measure accurate temperature dependence of electric conductivity down to 20 K in ultrahigh vacuum.

    PubMed

    Sakai, C; Takeda, S N; Daimon, H

    2013-07-01

    We have developed the new in situ electrical-conductivity measurement system which can be operated in ultrahigh vacuum (UHV) with accurate temperature measurement down to 20 K. This system is mainly composed of a new sample-holder fixing mechanism, a new movable conductivity-measurement mechanism, a cryostat, and two receptors for sample- and four-probe holders. Sample-holder is pushed strongly against the receptor, which is connected to a cryostat, by using this new sample-holder fixing mechanism to obtain high thermal conductivity. Test pieces on the sample-holders have been cooled down to about 20 K using this fixing mechanism, although they were cooled down to only about 60 K without this mechanism. Four probes are able to be touched to a sample surface using this new movable conductivity-measurement mechanism for measuring electrical conductivity after making film on substrates or obtaining clean surfaces by cleavage, flashing, and so on. Accurate temperature measurement is possible since the sample can be transferred with a thermocouple and∕or diode being attached directly to the sample. A single crystal of Bi-based copper oxide high-Tc superconductor (HTSC) was cleaved in UHV to obtain clean surface, and its superconducting critical temperature has been successfully measured in situ. The importance of in situ measurement of resistance in UHV was demonstrated for this HTSC before and after cesium (Cs) adsorption on its surface. The Tc onset increase and the Tc offset decrease by Cs adsorption were observed.

  5. Voltammetry under a Controlled Temperature Gradient

    PubMed Central

    Krejci, Jan; Sajdlova, Zuzana; Krejci, Jan; Marvanek, Tomas

    2010-01-01

    Electrochemical measurements are generally done under isothermal conditions. Here we report on the application of a controlled temperature gradient between the working electrode surface and the solution. Using electrochemical sensors prepared on ceramic materials with extremely high specific heat conductivity, the temperature gradient between the electrode and solution was applied here as a second driving force. This application of the Soret phenomenon increases the mass transfer in the Nernst layer and enables more accurate control of the electrode response enhancement by a combination of diffusion and thermal diffusion. We have thus studied the effect of Soret phenomenon by cyclic voltammetry measurements in ferro/ferricyanide. The time dependence of sensor response disappears when applying the Soret phenomenon, and the complicated shape of the cyclic voltammogram is replaced by a simple exponential curve. We have derived the Cotrell-Soret equation describing the steady-state response with an applied temperature difference. PMID:22163578

  6. Water Temperature Controls in Arctic Basins

    NASA Astrophysics Data System (ADS)

    Neilson, B. T.; King, T.; Schmadel, N. M.; Heavilin, J.; Overbeck, L. D.; Kane, D. L.

    2015-12-01

    Understanding the dynamics of heat transfer mechanisms in arctic rivers is critical for forecasting the effects of climate change on river temperatures. Building on the collection of key data and a dynamic river temperature model that accounts for heat fluxes found important in temperate climates, we were able to identify portions of an arctic basin and hydrologic conditions for which heat flux dynamics differ from those found in temperate systems. During the open water season, similarities in heat flux influences include dominant shortwave radiation, greater surface exchanges than bed exchanges and greater influences of lateral inflows in the lower order portions of the basin. Differing from temperate systems, the heat flux contribution of net longwave radiation is consistently negative and both latent heat and bed friction are negligible. Despite these differences, accounting for the bulk lateral inflows from the basin resulted in accurate predictions during higher flows. Under lower flow conditions, however, lateral inflows were limited and resulting temperature predictions were poor. Work in a temperate system demonstrated that spatial variability in hydraulics influencing stream residence times are necessary for accurate river temperature predictions. Because heat fluxes at the air-water interface become increasingly dominant at low flows and these fluxes are sensitive to parameters representing the water surface area to volume ratio, similar to temperate systems, we expect that high-resolution representations of stream geometry and hydraulics are important both for accurate flux and residence time estimates. Furthermore, given the highly dynamic nature of flows in arctic basins, we anticipate that detailed information regarding spatially variable hydraulic characteristics (e.g., channel width, depth, and velocity) is critical for accurate predictions in low arctic rivers through a large range of flow conditions. Upon identifying key processes controlling

  7. An accurate analytic representation of the temperature dependence of nonresonant nuclear reaction rate coefficients

    NASA Astrophysics Data System (ADS)

    Shizgal, Bernie D.

    2016-12-01

    There has been intense interest for several decades by different research groups to accurately model the temperature dependence of a large number of nuclear reaction rate coefficients for both light and heavy nuclides. The rate coefficient, k(T) , is given by the Maxwellian average of the reactive cross section expressed in terms of the astrophysical factor, S(E) , which for nonresonant reactions is generally written as a power series in the relative energy E. A computationally efficient algorithm for the temperature dependence of nuclear reaction rate coefficients is required for fusion reactor research and for models of nucleosynthesis and stellar evolution. In this paper, an accurate analytical expression for the temperature dependence of nuclear reaction rate coefficients is provided in terms of τ = 3(b / 2) 2/3 or equivalently, T - 1/3 , where b = B /√{kB T }, B is the Gamow factor and kB is the Boltzmann constant. The methodology is appropriate for all nonresonant nuclear reactions for which S(E) can be represented as a power series in E. The explicit expression for the rate coefficient versus temperature is derived with the asymptotic expansions of the moments of w(E) = exp(- E /kB T - B /√{ E }) in terms of τ. The zeroth order moment is the familiar Gaussian approximation to the rate coefficient. Results are reported for the representative reactions D(d, p)T, D(d, n)3He and 7Li(p, α) α and compared with several different fitting procedures reported in the literature.

  8. Core body temperature control by total liquid ventilation using a virtual lung temperature sensor.

    PubMed

    Nadeau, Mathieu; Micheau, Philippe; Robert, Raymond; Avoine, Olivier; Tissier, Renaud; Germim, Pamela Samanta; Vandamme, Jonathan; Praud, Jean-Paul; Walti, Herve

    2014-12-01

    In total liquid ventilation (TLV), the lungs are filled with a breathable liquid perfluorocarbon (PFC) while a liquid ventilator ensures proper gas exchange by renewal of a tidal volume of oxygenated and temperature-controlled PFC. Given the rapid changes in core body temperature generated by TLV using the lung has a heat exchanger, it is crucial to have accurate and reliable core body temperature monitoring and control. This study presents the design of a virtual lung temperature sensor to control core temperature. In the first step, the virtual sensor, using expired PFC to estimate lung temperature noninvasively, was validated both in vitro and in vivo. The virtual lung temperature was then used to rapidly and automatically control core temperature. Experimentations were performed using the Inolivent-5.0 liquid ventilator with a feedback controller to modulate inspired PFC temperature thereby controlling lung temperature. The in vivo experimental protocol was conducted on seven newborn lambs instrumented with temperature sensors at the femoral artery, pulmonary artery, oesophagus, right ear drum, and rectum. After stabilization in conventional mechanical ventilation, TLV was initiated with fast hypothermia induction, followed by slow posthypothermic rewarming for 1 h, then by fast rewarming to normothermia and finally a second fast hypothermia induction phase. Results showed that the virtual lung temperature was able to provide an accurate estimation of systemic arterial temperature. Results also demonstrate that TLV can precisely control core body temperature and can be favorably compared to extracorporeal circulation in terms of speed.

  9. Accurate force fields and methods for modelling organic molecular crystals at finite temperatures.

    PubMed

    Nyman, Jonas; Pundyke, Orla Sheehan; Day, Graeme M

    2016-06-21

    We present an assessment of the performance of several force fields for modelling intermolecular interactions in organic molecular crystals using the X23 benchmark set. The performance of the force fields is compared to several popular dispersion corrected density functional methods. In addition, we present our implementation of lattice vibrational free energy calculations in the quasi-harmonic approximation, using several methods to account for phonon dispersion. This allows us to also benchmark the force fields' reproduction of finite temperature crystal structures. The results demonstrate that anisotropic atom-atom multipole-based force fields can be as accurate as several popular DFT-D methods, but have errors 2-3 times larger than the current best DFT-D methods. The largest error in the examined force fields is a systematic underestimation of the (absolute) lattice energy.

  10. The Game of Temperature Control.

    ERIC Educational Resources Information Center

    Paine, Clair

    1980-01-01

    Describes a game intended as a laboratory exercise to help students understand temperature control in higher animals, discover how endotherms and ectotherms deal with gains and/or losses of heat, and discover the habits and habitats of higher animals and their influence on thermal regulation. (Author/SA)

  11. Linear signal noise summer accurately determines and controls S/N ratio

    NASA Technical Reports Server (NTRS)

    Sundry, J. L.

    1966-01-01

    Linear signal noise summer precisely controls the relative power levels of signal and noise, and mixes them linearly in accurately known ratios. The S/N ratio accuracy and stability are greatly improved by this technique and are attained simultaneously.

  12. Controlled temperature photothermal tissue welding.

    PubMed

    C Ilesiz, I

    1999-07-01

    Photothermal tissue welding has been investigated as an alternative surgical tool to improve bonding of a variety of severed tissues. Yet, after almost two decades of research, inconsistencies in interpretation of experimental reports and, consequently, mechanism of this photothermal process as well as control of dosimetry remain an enigma. Widespread clinical use may greatly depend on full automation of light dosimetry to perform durable and reproducible welds with minimal thermal damage to surrounding and/or underlying tissues. Recognizing photothermal damage as a rate process, radiometrically measured tissue surface temperature has been studied as an indirect marker of tissue status during laser irradiation. Dosimetry control systems and surgical devices were developed to perform controlled temperature tissue welding using surface temperature feedback from the site of laser impact. Nevertheless, end points that mark the completion of a durable and stable weld have not been precisely identified, and subsequently, not incorporated into dosimetry control algorithms. This manuscript reviews thermal dosimetry control systems of the 1990s in an attempt to systematically indicate the difficulties encountered so far and to elaborate on major issues for photothermal tissue welding to become a clinical reality in the new millennium. © 1999 Society of Photo-Optical Instrumentation Engineers.

  13. Automatic temperature controlled retinal photocoagulation

    NASA Astrophysics Data System (ADS)

    Schlott, Kerstin; Koinzer, Stefan; Ptaszynski, Lars; Bever, Marco; Baade, Alex; Roider, Johann; Birngruber, Reginald; Brinkmann, Ralf

    2012-06-01

    Laser coagulation is a treatment method for many retinal diseases. Due to variations in fundus pigmentation and light scattering inside the eye globe, different lesion strengths are often achieved. The aim of this work is to realize an automatic feedback algorithm to generate desired lesion strengths by controlling the retinal temperature increase with the irradiation time. Optoacoustics afford non-invasive retinal temperature monitoring during laser treatment. A 75 ns/523 nm Q-switched Nd:YLF laser was used to excite the temperature-dependent pressure amplitudes, which were detected at the cornea by an ultrasonic transducer embedded in a contact lens. A 532 nm continuous wave Nd:YAG laser served for photocoagulation. The ED50 temperatures, for which the probability of ophthalmoscopically visible lesions after one hour in vivo in rabbits was 50%, varied from 63°C for 20 ms to 49°C for 400 ms. Arrhenius parameters were extracted as ΔE=273 J mol-1 and A=3.1044 s-1. Control algorithms for mild and strong lesions were developed, which led to average lesion diameters of 162+/-34 μm and 189+/-34 μm, respectively. It could be demonstrated that the sizes of the automatically controlled lesions were widely independent of the treatment laser power and the retinal pigmentation.

  14. Automatic temperature controlled retinal photocoagulation.

    PubMed

    Schlott, Kerstin; Koinzer, Stefan; Ptaszynski, Lars; Bever, Marco; Baade, Alex; Roider, Johann; Birngruber, Reginald; Brinkmann, Ralf

    2012-06-01

    Laser coagulation is a treatment method for many retinal diseases. Due to variations in fundus pigmentation and light scattering inside the eye globe, different lesion strengths are often achieved. The aim of this work is to realize an automatic feedback algorithm to generate desired lesion strengths by controlling the retinal temperature increase with the irradiation time. Optoacoustics afford non-invasive retinal temperature monitoring during laser treatment. A 75 ns/523 nm Q-switched Nd:YLF laser was used to excite the temperature-dependent pressure amplitudes, which were detected at the cornea by an ultrasonic transducer embedded in a contact lens. A 532 nm continuous wave Nd:YAG laser served for photocoagulation. The ED50 temperatures, for which the probability of ophthalmoscopically visible lesions after one hour in vivo in rabbits was 50%, varied from 63°C for 20 ms to 49°C for 400 ms. Arrhenius parameters were extracted as ΔE=273 J mol(-1) and A=3 x 10(44) s(-1). Control algorithms for mild and strong lesions were developed, which led to average lesion diameters of 162 ± 34 μm and 189 ± 34 μm, respectively. It could be demonstrated that the sizes of the automatically controlled lesions were widely independent of the treatment laser power and the retinal pigmentation.

  15. Fuzzy Logic Controller for Low Temperature Application

    NASA Technical Reports Server (NTRS)

    Hahn, Inseob; Gonzalez, A.; Barmatz, M.

    1996-01-01

    The most common temperature controller used in low temperature experiments is the proportional-integral-derivative (PID) controller due to its simplicity and robustness. However, the performance of temperature regulation using the PID controller depends on initial parameter setup, which often requires operator's expert knowledge on the system. In this paper, we present a computer-assisted temperature controller based on the well known.

  16. Accurate prediction of severe allergic reactions by a small set of environmental parameters (NDVI, temperature).

    PubMed

    Notas, George; Bariotakis, Michail; Kalogrias, Vaios; Andrianaki, Maria; Azariadis, Kalliopi; Kampouri, Errika; Theodoropoulou, Katerina; Lavrentaki, Katerina; Kastrinakis, Stelios; Kampa, Marilena; Agouridakis, Panagiotis; Pirintsos, Stergios; Castanas, Elias

    2015-01-01

    Severe allergic reactions of unknown etiology,necessitating a hospital visit, have an important impact in the life of affected individuals and impose a major economic burden to societies. The prediction of clinically severe allergic reactions would be of great importance, but current attempts have been limited by the lack of a well-founded applicable methodology and the wide spatiotemporal distribution of allergic reactions. The valid prediction of severe allergies (and especially those needing hospital treatment) in a region, could alert health authorities and implicated individuals to take appropriate preemptive measures. In the present report we have collecterd visits for serious allergic reactions of unknown etiology from two major hospitals in the island of Crete, for two distinct time periods (validation and test sets). We have used the Normalized Difference Vegetation Index (NDVI), a satellite-based, freely available measurement, which is an indicator of live green vegetation at a given geographic area, and a set of meteorological data to develop a model capable of describing and predicting severe allergic reaction frequency. Our analysis has retained NDVI and temperature as accurate identifiers and predictors of increased hospital severe allergic reactions visits. Our approach may contribute towards the development of satellite-based modules, for the prediction of severe allergic reactions in specific, well-defined geographical areas. It could also probably be used for the prediction of other environment related diseases and conditions.

  17. Accurate Prediction of Severe Allergic Reactions by a Small Set of Environmental Parameters (NDVI, Temperature)

    PubMed Central

    Andrianaki, Maria; Azariadis, Kalliopi; Kampouri, Errika; Theodoropoulou, Katerina; Lavrentaki, Katerina; Kastrinakis, Stelios; Kampa, Marilena; Agouridakis, Panagiotis; Pirintsos, Stergios; Castanas, Elias

    2015-01-01

    Severe allergic reactions of unknown etiology,necessitating a hospital visit, have an important impact in the life of affected individuals and impose a major economic burden to societies. The prediction of clinically severe allergic reactions would be of great importance, but current attempts have been limited by the lack of a well-founded applicable methodology and the wide spatiotemporal distribution of allergic reactions. The valid prediction of severe allergies (and especially those needing hospital treatment) in a region, could alert health authorities and implicated individuals to take appropriate preemptive measures. In the present report we have collecterd visits for serious allergic reactions of unknown etiology from two major hospitals in the island of Crete, for two distinct time periods (validation and test sets). We have used the Normalized Difference Vegetation Index (NDVI), a satellite-based, freely available measurement, which is an indicator of live green vegetation at a given geographic area, and a set of meteorological data to develop a model capable of describing and predicting severe allergic reaction frequency. Our analysis has retained NDVI and temperature as accurate identifiers and predictors of increased hospital severe allergic reactions visits. Our approach may contribute towards the development of satellite-based modules, for the prediction of severe allergic reactions in specific, well-defined geographical areas. It could also probably be used for the prediction of other environment related diseases and conditions. PMID:25794106

  18. Temperature controller for a fluid cooled garment

    NASA Technical Reports Server (NTRS)

    Chambers, A. B.; Blackaby, J. R.; Billingham, J. (Inventor)

    1973-01-01

    An automatic controller for controlling the inlet temperature of the coolant to a fluid cooled garment without requiring skin sensors is described. Temperature is controlled by the wearer's evaporative water loss rate.

  19. High temperature control rod assembly

    DOEpatents

    Vollman, Russell E.

    1991-01-01

    A high temperature nuclear control rod assembly comprises a plurality of substantially cylindrical segments flexibly joined together in succession by ball joints. The segments are made of a high temperature graphite or carbon-carbon composite. The segment includes a hollow cylindrical sleeve which has an opening for receiving neutron-absorbing material in the form of pellets or compacted rings. The sleeve has a threaded sleeve bore and outer threaded surface. A cylindrical support post has a threaded shaft at one end which is threadably engaged with the sleeve bore to rigidly couple the support post to the sleeve. The other end of the post is formed with a ball portion. A hollow cylindrical collar has an inner threaded surface engageable with the outer threaded surface of the sleeve to rigidly couple the collar to the sleeve. the collar also has a socket portion which cooperates with the ball portion to flexibly connect segments together to form a ball and socket-type joint. In another embodiment, the segment comprises a support member which has a threaded shaft portion and a ball surface portion. The threaded shaft portion is engageable with an inner threaded surface of a ring for rigidly coupling the support member to the ring. The ring in turn has an outer surface at one end which is threadably engageably with a hollow cylindrical sleeve. The other end of the sleeve is formed with a socket portion for engagement with a ball portion of the support member. In yet another embodiment, a secondary rod is slidably inserted in a hollow channel through the center of the segment to provide additional strength. A method for controlling a nuclear reactor utilizing the control rod assembly is also included.

  20. Children Can Accurately Monitor and Control Their Number-Line Estimation Performance

    ERIC Educational Resources Information Center

    Wall, Jenna L.; Thompson, Clarissa A.; Dunlosky, John; Merriman, William E.

    2016-01-01

    Accurate monitoring and control are essential for effective self-regulated learning. These metacognitive abilities may be particularly important for developing math skills, such as when children are deciding whether a math task is difficult or whether they made a mistake on a particular item. The present experiments investigate children's ability…

  1. Temperature-Controlled Chameleonlike Cloak

    NASA Astrophysics Data System (ADS)

    Peng, Ruiguang; Xiao, Zongqi; Zhao, Qian; Zhang, Fuli; Meng, Yonggang; Li, Bo; Zhou, Ji; Fan, Yuancheng; Zhang, Peng; Shen, Nian-Hai; Koschny, Thomas; Soukoulis, Costas M.

    2017-01-01

    Invisibility cloaking based on transformation optics has brought about unlimited space for reverie. However, the design and fabrication of transformation-optics-based cloaks still remain fairly challenging because of the complicated, even extreme, material prescriptions, including its meticulously engineered anisotropy, inhomogeneity and singularity. And almost all the state-of-the-art cloaking devices work within a narrow and invariable frequency band. Here, we propose a novel mechanism for all-dielectric temperature-controllable cloaks. A prototype device was designed and fabricated with SrTiO3 ferroelectric cuboids as building blocks, and its cloaking effects were successfully demonstrated, including its frequency-agile invisibility by varying temperature. It revealed that the predesignated cloaking device based on our proposed strategy could be directly scaled in dimensions to operate at different frequency regions, without the necessity for further efforts of redesign. Our work opens the door towards the realization of tunable cloaking devices for various practical applications and provides a simple strategy to readily extend the cloaking band from microwave to terahertz regimes without the need for reconfiguration.

  2. Temperature Effects and Compensation-Control Methods

    PubMed Central

    Xia, Dunzhu; Chen, Shuling; Wang, Shourong; Li, Hongsheng

    2009-01-01

    In the analysis of the effects of temperature on the performance of microgyroscopes, it is found that the resonant frequency of the microgyroscope decreases linearly as the temperature increases, and the quality factor changes drastically at low temperatures. Moreover, the zero bias changes greatly with temperature variations. To reduce the temperature effects on the microgyroscope, temperature compensation-control methods are proposed. In the first place, a BP (Back Propagation) neural network and polynomial fitting are utilized for building the temperature model of the microgyroscope. Considering the simplicity and real-time requirements, piecewise polynomial fitting is applied in the temperature compensation system. Then, an integral-separated PID (Proportion Integration Differentiation) control algorithm is adopted in the temperature control system, which can stabilize the temperature inside the microgyrocope in pursuing its optimal performance. Experimental results reveal that the combination of microgyroscope temperature compensation and control methods is both realizable and effective in a miniaturized microgyroscope prototype. PMID:22408509

  3. An accurate air temperature measurement system based on an envelope pulsed ultrasonic time-of-flight technique

    NASA Astrophysics Data System (ADS)

    Huang, Y. S.; Huang, Y. P.; Huang, K. N.; Young, M. S.

    2007-11-01

    A new microcomputer based air temperature measurement system is presented. An accurate temperature measurement is derived from the measurement of sound velocity by using an ultrasonic time-of-flight (TOF) technique. The study proposes a novel algorithm that combines both amplitude modulation (AM) and phase modulation (PM) to get the TOF measurement. The proposed system uses the AM and PM envelope square waveform (APESW) to reduce the error caused by inertia delay. The APESW ultrasonic driving waveform causes an envelope zero and phase inversion phenomenon in the relative waveform of the receiver. To accurately achieve a TOF measurement, the phase inversion phenomenon was used to sufficiently identify the measurement pulse in the received waveform. Additionally, a counter clock technique was combined to compute the phase shifts of the last incomplete cycle for TOF. The presented system can obtain 0.1% TOF resolution for the period corresponding to the 40kHz frequency ultrasonic wave. Consequently, with the integration of a humidity compensation algorithm, a highly accurate and high resolution temperature measurement can be achieved using the accurate TOF measurement. Experimental results indicate that the combined standard uncertainty of the temperature measurement is approximately 0.39°C. The main advantages of this system are high resolution measurements, narrow bandwidth requirements, and ease of implementation.

  4. Accurate and efficient integration for molecular dynamics simulations at constant temperature and pressure.

    PubMed

    Lippert, Ross A; Predescu, Cristian; Ierardi, Douglas J; Mackenzie, Kenneth M; Eastwood, Michael P; Dror, Ron O; Shaw, David E

    2013-10-28

    In molecular dynamics simulations, control over temperature and pressure is typically achieved by augmenting the original system with additional dynamical variables to create a thermostat and a barostat, respectively. These variables generally evolve on timescales much longer than those of particle motion, but typical integrator implementations update the additional variables along with the particle positions and momenta at each time step. We present a framework that replaces the traditional integration procedure with separate barostat, thermostat, and Newtonian particle motion updates, allowing thermostat and barostat updates to be applied infrequently. Such infrequent updates provide a particularly substantial performance advantage for simulations parallelized across many computer processors, because thermostat and barostat updates typically require communication among all processors. Infrequent updates can also improve accuracy by alleviating certain sources of error associated with limited-precision arithmetic. In addition, separating the barostat, thermostat, and particle motion update steps reduces certain truncation errors, bringing the time-average pressure closer to its target value. Finally, this framework, which we have implemented on both general-purpose and special-purpose hardware, reduces software complexity and improves software modularity.

  5. Accurate control of a Bose-Einstein condensate by managing the atomic interaction

    SciTech Connect

    Morales-Molina, L.; Arevalo, E.

    2010-07-15

    We exploit the variation of the atomic interaction in order to move ultracold atoms with attractive interaction across an ac-driven periodic lattice. By breaking relevant symmetries, a gathering of atoms is achieved. Accurate control of the gathered atoms' positions can be demonstrated via the control of the atomic localization process. The localization process is analyzed with the help of the nonlinear Floquet states where the Landau-Zener tunneling between states is observed and controlled. Transport effects in the presence of disorder are discussed.

  6. Performance of a flight qualified, thermoelectrically temperature controlled QCM sensor with power supply, thermal controller and signal processor

    NASA Technical Reports Server (NTRS)

    Wallace, D. A.

    1980-01-01

    A thermoelectrically temperature controlled quartz crystal microbalance (QCM) system was developed for the measurement of ion thrustor generated mercury contamination on spacecraft. Meaningful flux rate measurements dictated an accurately held sensing crystal temperature despite spacecraft surface temperature variations from -35 C to +60 C over the flight temperature range. An electronic control unit was developed with magentic amplifier transformer secondary power supply, thermal control electronics, crystal temperature analog conditioning and a multiplexed 16 bit frequency encoder.

  7. ON-LINE SELF-CALIBRATING SINGLE CRYSTAL SAPPHIRE OPTICAL SENSOR INSTRUMENTATION FOR ACCURATE AND RELIABLE COAL GASIFIER TEMPERATURE MEASUREMENT

    SciTech Connect

    Kristie Cooper; Gary Pickrell; Anbo Wang; Zhengyu Huang

    2004-04-01

    This report summarizes technical progress over the third six month period of the Phase II program ''On-Line Self-Calibrating Single Crystal Sapphire Optical Sensor Instrumentation for Accurate and Reliable Coal Gasifier Temperature Measurement'', funded by the Federal Energy Technology Center of the U.S. Department of Energy, and performed by the Center for Photonics Technology of the Bradley Department of Electrical and Computer Engineering at Virginia Tech. The outcome of the first phase of this program was the selection of broadband polarimetric differential interferometry (BPDI) for further prototype instrumentation development. This approach is based on the measurement of the optical path difference (OPD) between two orthogonally polarized light beams in a single-crystal sapphire disk. The objective of this program is to bring the BPDI sensor technology, which has already been demonstrated in the laboratory, to a level where the sensor can be deployed in the harsh industrial environments and will become commercially viable. Research efforts were focused on sensor probe design and machining, sensor electronics design, software algorithm design, sensor field installation procedures, and sensor remote data access and control. Field testing will begin in the next several weeks.

  8. Accurate radiation temperature and chemical potential from quantitative photoluminescence analysis of hot carrier populations

    NASA Astrophysics Data System (ADS)

    Gibelli, François; Lombez, Laurent; Guillemoles, Jean-François

    2017-02-01

    In order to characterize hot carrier populations in semiconductors, photoluminescence measurement is a convenient tool, enabling us to probe the carrier thermodynamical properties in a contactless way. However, the analysis of the photoluminescence spectra is based on some assumptions which will be discussed in this work. We especially emphasize the importance of the variation of the material absorptivity that should be considered to access accurate thermodynamical properties of the carriers, especially by varying the excitation power. The proposed method enables us to obtain more accurate results of thermodynamical properties by taking into account a rigorous physical description and finds direct application in investigating hot carrier solar cells, which are an adequate concept for achieving high conversion efficiencies with a relatively simple device architecture.

  9. Accurate radiation temperature and chemical potential from quantitative photoluminescence analysis of hot carrier populations.

    PubMed

    Gibelli, François; Lombez, Laurent; Guillemoles, Jean-François

    2017-02-15

    In order to characterize hot carrier populations in semiconductors, photoluminescence measurement is a convenient tool, enabling us to probe the carrier thermodynamical properties in a contactless way. However, the analysis of the photoluminescence spectra is based on some assumptions which will be discussed in this work. We especially emphasize the importance of the variation of the material absorptivity that should be considered to access accurate thermodynamical properties of the carriers, especially by varying the excitation power. The proposed method enables us to obtain more accurate results of thermodynamical properties by taking into account a rigorous physical description and finds direct application in investigating hot carrier solar cells, which are an adequate concept for achieving high conversion efficiencies with a relatively simple device architecture.

  10. Accurate determination of specific heat at high temperatures using the flash diffusivity method

    NASA Technical Reports Server (NTRS)

    Vandersande, J. W.; Zoltan, A.; Wood, C.

    1989-01-01

    The flash diffusivity method of Parker et al. (1961) was used to measure accurately the specific heat of test samples simultaneously with thermal diffusivity, thus obtaining the thermal conductivity of these materials directly. The accuracy of data obtained on two types of materials (n-type silicon-germanium alloys and niobium), was + or - 3 percent. It is shown that the method is applicable up to at least 1300 K.

  11. Fluorescence-based temperature control for polymerase chain reaction.

    PubMed

    Sanford, Lindsay N; Wittwer, Carl T

    2014-03-01

    The ability to accurately monitor solution temperature is important for the polymerase chain reaction (PCR). Robust amplification during PCR is contingent on the solution reaching denaturation and annealing temperatures. By correlating temperature to the fluorescence of a passive dye, noninvasive monitoring of solution temperatures is possible. The temperature sensitivity of 22 fluorescent dyes was assessed. Emission spectra were monitored and the change in fluorescence between 45 and 95°C was quantified. Seven dyes decreased in intensity as the temperature increased, and 15 were variable depending on the excitation wavelength. Sulforhodamine B (monosodium salt) exhibited a fold change in fluorescence of 2.85. Faster PCR minimizes cycling times and improves turnaround time, throughput, and specificity. If temperature measurements are accurate, no holding period is required even at rapid speeds. A custom instrument using fluorescence-based temperature monitoring with dynamic feedback control for temperature cycling amplified a fragment surrounding rs917118 from genomic DNA in 3min and 45s using 35 cycles, allowing subsequent genotyping by high-resolution melting analysis. Gold-standard thermocouple readings and fluorescence-based temperature differences were 0.29±0.17 and 0.96±0.26°C at annealing and denaturation, respectively. This new method for temperature cycling may allow faster speeds for PCR than currently considered possible.

  12. Evaluation of a low-cost and accurate ocean temperature logger on subsurface mooring systems

    SciTech Connect

    Tian, Chuan; Deng, Zhiqun; Lu, Jun; Xu, Xiaoyang; Zhao, Wei; Xu, Ming

    2014-06-23

    Monitoring seawater temperature is important to understanding evolving ocean processes. To monitor internal waves or ocean mixing, a large number of temperature loggers are typically mounted on subsurface mooring systems to obtain high-resolution temperature data at different water depths. In this study, we redesigned and evaluated a compact, low-cost, self-contained, high-resolution and high-accuracy ocean temperature logger, TC-1121. The newly designed TC-1121 loggers are smaller, more robust, and their sampling intervals can be automatically changed by indicated events. They have been widely used in many mooring systems to study internal wave and ocean mixing. The logger’s fundamental design, noise analysis, calibration, drift test, and a long-term sea trial are discussed in this paper.

  13. A novel method for more accurately mapping the surface temperature of ultrasonic transducers.

    PubMed

    Axell, Richard G; Hopper, Richard H; Jarritt, Peter H; Oxley, Chris H

    2011-10-01

    This paper introduces a novel method for measuring the surface temperature of ultrasound transducer membranes and compares it with two standard measurement techniques. The surface temperature rise was measured as defined in the IEC Standard 60601-2-37. The measurement techniques were (i) thermocouple, (ii) thermal camera and (iii) novel infra-red (IR) "micro-sensor." Peak transducer surface measurements taken with the thermocouple and thermal camera were -3.7 ± 0.7 (95% CI)°C and -4.3 ± 1.8 (95% CI)°C, respectively, within the limits of the IEC Standard. Measurements taken with the novel IR micro-sensor exceeded these limits by 3.3 ± 0.9 (95% CI)°C. The ambiguity between our novel method and the standard techniques could have direct patient safety implications because the IR micro-sensor measurements were beyond set limits. The spatial resolution of the measurement technique is not well defined in the IEC Standard and this has to be taken into consideration when selecting which measurement technique is used to determine the maximum surface temperature.

  14. A proportional temperature controller with automatic shutoff

    NASA Astrophysics Data System (ADS)

    Lucich, G. M.; Holland, P. W.

    1980-08-01

    A sensitive, proportional temperature controller useful in the temperature range from 40 to 400 C with an accuracy of plus or minus 0.1 C is described. It is potentially useful for regulating temperatures in air chambers, liquid baths, furnaces and reaction vessels and for other applications. This instrument was developed to control the duration and temperature of the heating cycle of a charcoal filled adsorber that is part of a special helium analyzer. The controller was made from commercially available parts and can be easily modified to provide continuous temperature control. The circuit is solid state and employs no electromechanical devices. Over a 2 year period of use as a component of the special helium analyzer, this temperature controller performed successfully and required no maintenance.

  15. Variable temperature seat climate control system

    DOEpatents

    Karunasiri, Tissa R.; Gallup, David F.; Noles, David R.; Gregory, Christian T.

    1997-05-06

    A temperature climate control system comprises a variable temperature seat, at least one heat pump, at least one heat pump temperature sensor, and a controller. Each heat pump comprises a number of Peltier thermoelectric modules for temperature conditioning the air in a main heat exchanger and a main exchanger fan for passing the conditioned air from the main exchanger to the variable temperature seat. The Peltier modules and each main fan may be manually adjusted via a control switch or a control signal. Additionally, the temperature climate control system may comprise a number of additional temperature sensors to monitor the temperature of the ambient air surrounding the occupant as well as the temperature of the conditioned air directed to the occupant. The controller is configured to automatically regulate the operation of the Peltier modules and/or each main fan according to a temperature climate control logic designed both to maximize occupant comfort during normal operation, and minimize possible equipment damage, occupant discomfort, or occupant injury in the event of a heat pump malfunction.

  16. Computing Highly Accurate Spectroscopic Line Lists that Cover a Large Temperature Range for Characterization of Exoplanet Atmospheres

    NASA Astrophysics Data System (ADS)

    Lee, T. J.; Huang, X.; Schwenke, D. W.

    2013-12-01

    Over the last decade, it has become apparent that the most effective approach for determining highly accurate rotational and rovibrational line lists for molecules of interest in planetary atmospheres is through a combination of high-resolution laboratory experiments coupled with state-of-the art ab initio quantum chemistry methods. The approach involves computing the most accurate potential energy surface (PES) possible using state-of-the art electronic structure methods, followed by computing rotational and rovibrational energy levels using an exact variational method to solve the nuclear Schrödinger equation. Then, reliable experimental data from high-resolution experiments is used to refine the ab initio PES in order to improve the accuracy of the computed energy levels and transition energies. From the refinement step, we have been able to achieve an accuracy of approximately 0.015 cm-1 for rovibrational transition energies, and even better for purely rotational transitions. This combined 'experiment / theory' approach allows for determination of essentially a complete line list, with hundreds of millions of transitions, and having the transition energies and intensities be highly accurate. Our group has successfully applied this approach to determine highly accurate line lists for NH3 and CO2 (and isotopologues), and very recently for SO2 and isotopologues. Here I will report our latest results for SO2 including all isotopologues. Comparisons to the available data in HITRAN2012 and other available databases will be shown, though we note that our line lists SO2 are significantly more complete than any other databases. Since it is important to span a large temperature range in order to model the spectral signature of exoplanets, we will also demonstrate how the spectra change on going from low temperatures (100 K) to higher temperatures (500 K).

  17. Can an Atmospherically Forced Ocean Model Accurately Simulate Sea Surface Temperature During ENSO Events?

    DTIC Science & Technology

    2010-01-01

    Mateger, Herley E. Hurlburt, Alan J. Walloraft H a inleficed to offer this paper to the (Nanm of Confe ounce) (Dafe. P/ace and Classification of...temperature during ENSO events? By A. BIROL KARA.HARLEY E. HURLBURT*. CHARLIE N. BARRON. ALAN J. WALLCRAFT andE. JOSEPH METZGER, Naval Research...Quantifying SST errors from an OGCM in relation to atmospheric forcing variables. Ocean Modell. 29, 43-57. Urge. W. G., McWilliams , J. C. and Doney. S. C

  18. Cooling of Er(3+) with Tm(3+) for accurate temperature sensing using yttrium silicate compact powders.

    PubMed

    Rakov, Nikifor; Maciel, Glauco S

    2014-11-14

    Er(3+) doped nanocrystalline powders are extensively used for thermometry based on luminescence spectral analysis. The luminescence from Er(3+) is produced by a nonlinear (two-photon) absorption process which may generate strong internal heat by activation of nonradiative relaxation channels. If the heat dissipation is not efficient, as is the case for compact powders, there will be inaccurate readings of the temperature. Our proposed solution is to cool down Er(3+) by transferring part of its accumulated energy to another rare-earth element in the lattice. Here, we show our results for Er(3+)-Tm(3+) co-doped yttrium silicate powders prepared by combustion synthesis.

  19. Accurate High-Temperature Reaction Networks for Alternative Fuels: Butanol Isomers

    SciTech Connect

    Van Geem, K. M.; Pyl, S. P.; Marin, G. B.; Harper, M. R.; Green, W. H.

    2010-11-03

    Oxygenated hydrocarbons, particularly alcohol compounds, are being studied extensively as alternatives and additives to conventional fuels due to their propensity of decreasing soot formation and improving the octane number of gasoline. However, oxygenated fuels also increase the production of toxic byproducts, such as formaldehyde. To gain a better understanding of the oxygenated functional group’s influence on combustion properties—e.g., ignition delay at temperatures above the negative temperature coefficient regime, and the rate of benzene production, which is the common precursor to soot formation—a detailed pressure-dependent reaction network for n-butanol, sec-butanol, and tert-butanol consisting of 281 species and 3608 reactions is presented. The reaction network is validated against shock tube ignition delays and doped methane flame concentration profiles reported previously in the literature, in addition to newly acquired pyrolysis data. Good agreement between simulated and experimental data is achieved in all cases. Flux and sensitivity analyses for each set of experiments have been performed, and high-pressure-limit reaction rate coefficients for important pathways, e.g., the dehydration reactions of the butanol isomers, have been computed using statistical mechanics and quantum chemistry. The different alcohol decomposition pathways, i.e., the pathways from primary, secondary, and tertiary alcohols, are discussed. Furthermore, comparisons between ethanol and n-butanol, two primary alcohols, are presented, as they relate to ignition delay.

  20. Temperature controlling system using embedded equipment

    NASA Astrophysics Data System (ADS)

    Rob, R.; Tirian, G. O.; Panoiu, C.

    2017-01-01

    Present paper describes the functionality of a temperature controlling system using PIC 18F45K22 microcontroller. The ambient temperature is acquired with LM35 analogue sensor. The microcontroller program is realized with MikroC compiler and it is able to control the speed of a cooling fan with dc motor. The speed can be increased in functioning with the increasing of the ambient temperature.

  1. Alternate method for achieving temperature control in the -160 to +90 Celcius range

    NASA Technical Reports Server (NTRS)

    Johnson, Kenneth R. (Inventor)

    1995-01-01

    A single-pass method for accurate and precise temperature control in the -160 to +90 C range is discussed. The method exhibited minimal set-point overshoot during temperature transitions. Control to +/-2 C with transitions between set-points of 7 C per minute were achieved. The method uses commercially available temperature controllers and a gaseous nitrogen/liquid nitrogen mixer to dampen the amplitude of cold temperature spikes caused by liquid nitrogen pulsing.

  2. Phase Change Fabrics Control Temperature

    NASA Technical Reports Server (NTRS)

    2009-01-01

    Originally featured in Spinoff in 1997, Outlast Technologies Inc. (formerly Gateway Technologies Inc.) has built its entire product line on microencapsulated phase change materials, developed in Small Business Innovation Research (SBIR) contracts with Johnson Space Center after initial development for the U.S. Air Force. The Boulder, Colorado-based company acquired the exclusive patent rights and now integrates these materials into textiles or onto finished apparel, providing temperature regulation in bedding materials and a full line of apparel for both ordinary and extreme conditions.

  3. Control circuitry using electronic emulation of a synchro signal for accurate control of position and rate of rotation for shafts

    NASA Technical Reports Server (NTRS)

    Howard, David E. (Inventor); Smith, Dennis A. (Inventor)

    1991-01-01

    The invention disclosed is a digital circuit which emulates a synchro signal in a synchro-resolver follower system for precise control of shaft position and rotation at very low rotational rates. The invention replaces the synchro and drive motor in a synchro-resolver follower system with a digital and analog synchro emulation circuit for generating the resolver control signal. The synchro emulation circuit includes amplitude modulation means to provide relatively high frequency resolver excitation signals for accurate resolver response even with very low shaft rotation rates.

  4. Control Circuitry Using Electronic Emulation of a Synchro Signal for Accurate Control of Position and Rate of Rotation for Shafts

    NASA Technical Reports Server (NTRS)

    Howard, David E. (Inventor); Smith, Dennis A. (Inventor)

    1992-01-01

    The invention herein disclosed is a digital circuit which emulates a synchro signal in a synchro-resolver follower system for precise control of shaft position and rotation at very low rotational rates. The subject invention replaces the synchro and drive motor in a synchroresolver follower system with a digital and analog synchro emulation circuit for generating the resolver control signal. The synchro emulation circuit includes amplitude modulation means to provide relatively high frequency resolver excitation signals for accurate resolver response even with very low shaft rotation rates.

  5. Accurate real-time depth control for CP-SSOCT distal sensor based handheld microsurgery tools

    PubMed Central

    Cheon, Gyeong Woo; Huang, Yong; Cha, Jaepyeng; Gehlbach, Peter L.; Kang, Jin U.

    2015-01-01

    This paper presents a novel intuitive targeting and tracking scheme that utilizes a common-path swept source optical coherence tomography (CP-SSOCT) distal sensor integrated handheld microsurgical tool. To achieve micron-order precision control, a reliable and accurate OCT distal sensing method is required; simultaneously, a prediction algorithm is necessary to compensate for the system delay associated with the computational, mechanical and electronic latencies. Due to the multi-layered structure of retina, it is necessary to develop effective surface detection methods rather than simple peak detection. To achieve this, a shifted cross-correlation method is applied for surface detection in order to increase robustness and accuracy in distal sensing. A predictor based on Kalman filter was implemented for more precise motion compensation. The performance was first evaluated using an established dry phantom consisting of stacked cellophane tape. This was followed by evaluation in an ex-vivo bovine retina model to assess system accuracy and precision. The results demonstrate highly accurate depth targeting with less than 5 μm RMSE depth locking. PMID:26137393

  6. Controlling temperature in magnetic hyperthermia with low Curie temperature particles

    NASA Astrophysics Data System (ADS)

    Astefanoaei, Iordana; Dumitru, Ioan; Chiriac, Horia; Stancu, Alexandru

    2014-05-01

    Hyperthermia induced by the heating of magnetic particles (MPs) in alternating magnetic field receives a considerable attention in cancer therapy. An interesting development in the studies dedicated to magnetically based hyperthermia is the possibility to control the temperature using MPs with selective magnetic absorption properties. This paper analyzes the temperature field determined by the heating of MPs having low Curie temperature (a FeCrNbB particulate system) injected within a malignant tissue, subjected to an ac magnetic field. The temperature evolution within healthy and tumor tissues was analyzed by finite element method simulations in a thermo-fluid model. The cooling effect produced by blood flowing in blood vessels was considered. This effect is intensified at the increase of blood velocity. The FeCrNbB particles, having the Curie temperature close to the therapeutic range, transfer the heat more homogeneous in the tumor keeping the temperature within the therapeutic range in whole tumor volume. Having the possibility to automatically control the temperature within a tumor, these particle type opens new research horizons in the magnetic hyperthermia.

  7. A Simple Dewar/Cryostat for Thermally Equilibrating Samples at Known Temperatures for Accurate Cryogenic Luminescence Measurements.

    PubMed

    Weaver, Phoebe G; Jagow, Devin M; Portune, Cameron M; Kenney, John W

    2016-07-19

    The design and operation of a simple liquid nitrogen Dewar/cryostat apparatus based upon a small fused silica optical Dewar, a thermocouple assembly, and a CCD spectrograph are described. The experiments for which this Dewar/cryostat is designed require fast sample loading, fast sample freezing, fast alignment of the sample, accurate and stable sample temperatures, and small size and portability of the Dewar/cryostat cryogenic unit. When coupled with the fast data acquisition rates of the CCD spectrograph, this Dewar/cryostat is capable of supporting cryogenic luminescence spectroscopic measurements on luminescent samples at a series of known, stable temperatures in the 77-300 K range. A temperature-dependent study of the oxygen quenching of luminescence in a rhodium(III) transition metal complex is presented as an example of the type of investigation possible with this Dewar/cryostat. In the context of this apparatus, a stable temperature for cryogenic spectroscopy means a luminescent sample that is thermally equilibrated with either liquid nitrogen or gaseous nitrogen at a known measureable temperature that does not vary (ΔT < 0.1 K) during the short time scale (~1-10 sec) of the spectroscopic measurement by the CCD. The Dewar/cryostat works by taking advantage of the positive thermal gradient dT/dh that develops above liquid nitrogen level in the Dewar where h is the height of the sample above the liquid nitrogen level. The slow evaporation of the liquid nitrogen results in a slow increase in h over several hours and a consequent slow increase in the sample temperature T over this time period. A quickly acquired luminescence spectrum effectively catches the sample at a constant, thermally equilibrated temperature.

  8. Enabling accurate gate profile control with inline 3D-AFM

    NASA Astrophysics Data System (ADS)

    Bao, Tianming; Lopez, Andrew; Dawson, Dean

    2009-05-01

    The logic and memory semiconductor device technology strives to follow the aggressive ITRS roadmap. The ITRS calls for increased 3D metrology to meet the demand for tighter process control at 45nm and 32nm nodes. In particular, gate engineering has advanced to a level where conventional metrology by CD-SEM and optical scatterometry (OCD) faces fundamental limitations without involvement of 3D atomic force microscope (3D-AFM or CD-AFM). This paper reports recent progress in 3D-AFM to address the metrology need to control gate dimension in MOSFET transistor formation. 3D-AFM metrology measures the gate electrode at post-etch with the lowest measurement uncertainty for critical gate geometry, including linewidth, sidewall profile, sidewall angle (SWA), line width roughness (LWR), and line edge roughness (LER). 3D-AFM enables accurate gate profile control in three types of metrology applications: reference metrology to validate CD-SEM and OCD, inline depth or 3D monitoring, or replacing TEM for 3D characterization for engineering analysis.

  9. Internal Temperature Control For Vibration Testers

    NASA Technical Reports Server (NTRS)

    Dean, Richard J.

    1996-01-01

    Vibration test fixtures with internal thermal-transfer capabilities developed. Made of aluminum for rapid thermal transfer. Small size gives rapid response to changing temperatures, with better thermal control. Setup quicker and internal ducting facilitates access to parts being tested. In addition, internal flows smaller, so less energy consumed in maintaining desired temperature settings.

  10. Analysis of algebraic reconstruction technique for accurate imaging of gas temperature and concentration based on tunable diode laser absorption spectroscopy

    NASA Astrophysics Data System (ADS)

    Hui-Hui, Xia; Rui-Feng, Kan; Jian-Guo, Liu; Zhen-Yu, Xu; Ya-Bai, He

    2016-06-01

    An improved algebraic reconstruction technique (ART) combined with tunable diode laser absorption spectroscopy(TDLAS) is presented in this paper for determining two-dimensional (2D) distribution of H2O concentration and temperature in a simulated combustion flame. This work aims to simulate the reconstruction of spectroscopic measurements by a multi-view parallel-beam scanning geometry and analyze the effects of projection rays on reconstruction accuracy. It finally proves that reconstruction quality dramatically increases with the number of projection rays increasing until more than 180 for 20 × 20 grid, and after that point, the number of projection rays has little influence on reconstruction accuracy. It is clear that the temperature reconstruction results are more accurate than the water vapor concentration obtained by the traditional concentration calculation method. In the present study an innovative way to reduce the error of concentration reconstruction and improve the reconstruction quality greatly is also proposed, and the capability of this new method is evaluated by using appropriate assessment parameters. By using this new approach, not only the concentration reconstruction accuracy is greatly improved, but also a suitable parallel-beam arrangement is put forward for high reconstruction accuracy and simplicity of experimental validation. Finally, a bimodal structure of the combustion region is assumed to demonstrate the robustness and universality of the proposed method. Numerical investigation indicates that the proposed TDLAS tomographic algorithm is capable of detecting accurate temperature and concentration profiles. This feasible formula for reconstruction research is expected to resolve several key issues in practical combustion devices. Project supported by the Young Scientists Fund of the National Natural Science Foundation of China (Grant No. 61205151), the National Key Scientific Instrument and Equipment Development Project of China (Grant

  11. Raoult’s law revisited: accurately predicting equilibrium relative humidity points for humidity control experiments

    PubMed Central

    Bowler, Michael G.

    2017-01-01

    The humidity surrounding a sample is an important variable in scientific experiments. Biological samples in particular require not just a humid atmosphere but often a relative humidity (RH) that is in equilibrium with a stabilizing solution required to maintain the sample in the same state during measurements. The controlled dehydration of macromolecular crystals can lead to significant increases in crystal order, leading to higher diffraction quality. Devices that can accurately control the humidity surrounding crystals while monitoring diffraction have led to this technique being increasingly adopted, as the experiments become easier and more reproducible. Matching the RH to the mother liquor is the first step in allowing the stable mounting of a crystal. In previous work [Wheeler, Russi, Bowler & Bowler (2012). Acta Cryst. F68, 111–114], the equilibrium RHs were measured for a range of concentrations of the most commonly used precipitants in macromolecular crystallography and it was shown how these related to Raoult’s law for the equilibrium vapour pressure of water above a solution. However, a discrepancy between the measured values and those predicted by theory could not be explained. Here, a more precise humidity control device has been used to determine equilibrium RH points. The new results are in agreement with Raoult’s law. A simple argument in statistical mechanics is also presented, demonstrating that the equilibrium vapour pressure of a solvent is proportional to its mole fraction in an ideal solution: Raoult’s law. The same argument can be extended to the case where the solvent and solute molecules are of different sizes, as is the case with polymers. The results provide a framework for the correct maintenance of the RH surrounding a sample. PMID:28381983

  12. Raoult's law revisited: accurately predicting equilibrium relative humidity points for humidity control experiments.

    PubMed

    Bowler, Michael G; Bowler, David R; Bowler, Matthew W

    2017-04-01

    The humidity surrounding a sample is an important variable in scientific experiments. Biological samples in particular require not just a humid atmosphere but often a relative humidity (RH) that is in equilibrium with a stabilizing solution required to maintain the sample in the same state during measurements. The controlled dehydration of macromolecular crystals can lead to significant increases in crystal order, leading to higher diffraction quality. Devices that can accurately control the humidity surrounding crystals while monitoring diffraction have led to this technique being increasingly adopted, as the experiments become easier and more reproducible. Matching the RH to the mother liquor is the first step in allowing the stable mounting of a crystal. In previous work [Wheeler, Russi, Bowler & Bowler (2012). Acta Cryst. F68, 111-114], the equilibrium RHs were measured for a range of concentrations of the most commonly used precipitants in macromolecular crystallography and it was shown how these related to Raoult's law for the equilibrium vapour pressure of water above a solution. However, a discrepancy between the measured values and those predicted by theory could not be explained. Here, a more precise humidity control device has been used to determine equilibrium RH points. The new results are in agreement with Raoult's law. A simple argument in statistical mechanics is also presented, demonstrating that the equilibrium vapour pressure of a solvent is proportional to its mole fraction in an ideal solution: Raoult's law. The same argument can be extended to the case where the solvent and solute molecules are of different sizes, as is the case with polymers. The results provide a framework for the correct maintenance of the RH surrounding a sample.

  13. Mould temperature control during injection moulding process

    NASA Astrophysics Data System (ADS)

    Postawa, Przemyslaw; Stachowiak, Tomasz

    2015-05-01

    Mould temperature is one of the most important parameter in injection moulding process of thermoplastic polymers in particular semi crystalline polymers. There are a lots of methods of control mould temperature but it is not simple and easy to measure heat transfer precisely. Injection moulds have usually a large mass and this is equal also to large heat capacity of tools and its thermal inertia. Measuring temperature by using contact equipment causes a lot of mistakes, because that method is based on heat transfer between thermocouple and measured area of mould. Result of research of 3 different method of temperature control of mould surface were present in the publication. For this purpose a special experimental mould was made. Mould has eight independent cooling circuits which were connected to the thermo controller Wittmann with two circuits. The main aim of research was to determine the effect of normal process of injection moulding on temperature changing in different area of mould. Under the cavity 4 thermocouple were placed and connect to the recorder what gave a possibility of uploading data during injection process. For that research mould temperature was change in many different layouts. Data and sequences of changes in temperature collected during tests gave very interesting result for discussion. Furthermore use of differences in temperature profile of the mould causes different temperature profile recorded during injection moulding. Tests were made by using fallowing equipment: Krauss Maffei injection moulding machine KM65-C4 and thermo controller Wittmann TPplus2, Shini Rotameter, infrared camera TESTO-890 and thermocouple signal recorder with 4 thermocouples of diameter 1mm located in injection mould 3mm under cavity surface. Draft of experimental mould and thermocouple location were presented in the article, and results of research as a drafts and charts of temperature changing in different area of mould were included.

  14. Accurate Lineshapes from Sub-1 cm-1 Resolution Sum Frequency Generation Vibrational Spectroscopy of α-Pinene at Room Temperature

    SciTech Connect

    Mifflin, Amanda L.; Velarde Ruiz Esparza, Luis A.; Ho, Junming; Psciuk, Brian; Negre, Christian; Ebben, Carlena J.; Upshur, Mary Alice; Lu, Zhou; Strick, Benjamin; Thomson, Regan; Batista, Victor; Wang, Hongfei; Geiger, Franz M.

    2015-02-26

    Room temperature sub-wavenumber high-resolution broadband sum frequency generation (HR-BB-SFG) spectra of the common terpene (+)-α-pinene reveal ten peaks in the C–H stretching region. The spectral resolution exceeds that of Fourier transform infrared, femtosecond stimulated Raman, and traditional BB-SFG and scanning SFG spectroscopy of the same molecule. Experiment and simulation show the spectral lineshapes to be accurate. Homogeneous vibrational decoherence lifetimes of up to 1.7 psec are assigned to specific oscillators and compare favorably to lifetimes computed from density functional tight binding molecular dynamics calculations, while phase-resolved spectra yield orientation information for them. We propose the new spectroscopy as an attractive alternative to time-resolved vibrational spectroscopy or heterodyne-detection schemes for studying vibrational energy relaxation and vibrational coherences in molecules.

  15. Temperature control in interstitial laser cancer immunotherapy

    NASA Astrophysics Data System (ADS)

    Bandyopadhyay, Pradip K.; Holmes, Kyland; Burnett, Corinthius; Zharov, Vladimir P.

    2003-07-01

    Positive results of Laser-Assisted Cancer Immunotherapy (LACI) have been reported previously in the irradiation of superficial tumors. This paper reports the effect of LACI using laser interstitial therapy approach. We hypothesize that the maximum immuno response depends on laser induced tumor temperature. The measurement of tumor temperature is crucial to ensure necrosis by thermal damage and immuno response. Wister Furth female rats in this study were inoculated with 13762 MAT B III rat mammary adinocarcinoma. LACI started seven to ten days following inoculation. Contrary to surface irradation, we applied laser interstitial irradiation of tumor volume to maximize the energy deposition. A diode laser with a wavelength of 805 nm was used for tumor irradiation. The laser energy was delivered inside the tumor through a quartz fiber. Tumor temperature was measured with a micro thermocouple (interstitial), while the tumor surface temperature was controlled with an IR detector. The temperature feedback demonstrates that it is possible to maintain the average tumor temperature at the same level with reasonable accuracy in the desired range from 65°C-85°C. In some experiments we used microwave thermometry to control average temperature in deep tissue for considerable period of time, to cause maximum thermal damage to the tumor. The experimental set-up and the different temperature measurement techniques are reported in detail, including the advantages and disadvantages for each method.

  16. Turbine gas temperature measurement and control system

    NASA Technical Reports Server (NTRS)

    Webb, W. L.

    1973-01-01

    A fluidic Turbine Inlet Gas Temperature (TIGIT) Measurement and Control System was developed for use on a Pratt and Whitney Aircraft J58 engine. Based on engine operating requirements, criteria for high temperature materials selection, system design, and system performance were established. To minimize development and operational risk, the TIGT control system was designed to interface with an existing Exhaust Gas Temperature (EGT) Trim System and thereby modulate steady-state fuel flow to maintain a desired TIGT level. Extensive component and system testing was conducted including heated (2300F) vibration tests for the fluidic sensor and gas sampling probe, temperature and vibration tests on the system electronics, burner rig testing of the TIGT measurement system, and in excess of 100 hours of system testing on a J58 engine. (Modified author abstract)

  17. On-Line Self-Calibrating Single Crystal Sapphire Optical Sensor Instrumentation for Accurate and Reliable Coal Gasifier Temperature Measurement

    SciTech Connect

    Kristie Cooper; Gary Pickrell; Anbo Wang

    2005-11-01

    This report summarizes technical progress April-September 2005 on the Phase II program ''On-Line Self-Calibrating Single Crystal Sapphire Optical Sensor Instrumentation for Accurate and Reliable Coal Gasifier Temperature Measurement'', funded by the Federal Energy Technology Center of the U.S. Department of Energy, and performed by the Center for Photonics Technology of the Bradley Department of Electrical and Computer Engineering at Virginia Tech. The outcome of the first phase of this program was the selection of broadband polarimetric differential interferometry (BPDI) for further prototype instrumentation development. This approach is based on the measurement of the optical path difference (OPD) between two orthogonally polarized light beams in a single-crystal sapphire disk. The objective of this program is to bring the sensor technology, which has already been demonstrated in the laboratory, to a level where the sensor can be deployed in the harsh industrial environments and will become commercially viable. Due to the difficulties described on the last report, field testing of the BPDI system has not continued to date. However, we have developed an alternative high temperature sensing solution, which is described in this report. The sensing system will be installed and tested at TECO's Polk Power Station. Following a site visit in June 2005, our efforts have been focused on preparing for that field test, including he design of the sensor mechanical packaging, sensor electronics, the data transfer module, and the necessary software codes to accommodate this application.. We are currently ready to start sensor fabrication.

  18. On-Line Self-Calibrating Single Crystal Sapphire Optical Sensor Instrumentation for Accurate and Reliable Coal Gasifier Temperature Measurement

    SciTech Connect

    Kristie Cooper; Anbo Wang

    2007-03-31

    This report summarizes technical progress October 2006 - March 2007 on the Phase II program ''On-Line Self-Calibrating Single Crystal Sapphire Optical Sensor Instrumentation for Accurate and Reliable Coal Gasifier Temperature Measurement'', funded by the Federal Energy Technology Center of the U.S. Department of Energy, and performed by the Center for Photonics Technology of the Bradley Department of Electrical and Computer Engineering at Virginia Tech. The outcome of the first phase of this program was the selection of broadband polarimetric differential interferometry (BPDI) for further prototype instrumentation development. This approach is based on the measurement of the optical path difference (OPD) between two orthogonally polarized light beams in a single-crystal sapphire disk. During the second phase, an alternative high temperature sensing system based on Fabry-Perot interferometry was developed that offers a number of advantages over the BPDI solution. The objective of this program is to bring the sensor technology, which has already been demonstrated in the laboratory, to a level where the sensor can be deployed in the harsh industrial environments and will become commercially viable. The sapphire wafer-based interferometric sensing system that was installed at TECO's Polk Power Station remained in operation for seven months. Our efforts have been focused on monitoring and analyzing the real-time data collected, and preparing for a second field test.

  19. ON-LINE SELF-CALIBRATING SINGLE CRYSTAL SAPPHIRE OPTICAL SENSOR INSTRUMENTATION FOR ACCURATE AND RELIABLE COAL GASIFIER TEMPERATURE MEASUREMENT

    SciTech Connect

    Kristie Cooper; Gary Pickrell; Anbo Wang

    2003-11-01

    This report summarizes technical progress over the second six month period of the Phase II program ''On-Line Self-Calibrating Single Crystal Sapphire Optical Sensor Instrumentation for Accurate and Reliable Coal Gasifier Temperature Measurement'', funded by the Federal Energy Technology Center of the U.S. Department of Energy, and performed by the Center for Photonics Technology of the Bradley Department of Electrical and Computer Engineering at Virginia Tech. The outcome of the first phase of this program was the selection of broadband polarimetric differential interferometry (BPDI) for further prototype instrumentation development. This approach is based on the measurement of the optical path difference (OPD) between two orthogonally polarized light beams in a single-crystal sapphire disk. The objective of this program is to bring the BPDI sensor technology, which has already been demonstrated in the laboratory, to a level where the sensor can be deployed in the harsh industrial environments and will become commercially viable. Research efforts were focused on evaluating corrosion effects in single crystal sapphire at temperatures up to 1400 C, and designing the sensor mechanical packaging with input from Wabash River Power Plant. Upcoming meetings will establish details for the gasifier field test.

  20. ON-LINE SELF-CALIBRATING SINGLE CRYSTAL SAPPHIRE OPTICAL SENSOR INSTRUMENTATION FOR ACCURATE AND RELIABLE COAL GASIFIER TEMPERATURE MEASUREMENT

    SciTech Connect

    Kristie Cooper; Gary Pickrell; Anbo Wang; Zhengyu Huang; Yizheng Zhu

    2005-04-01

    This report summarizes technical progress October 2004-March 2005 on the Phase II program ''On-Line Self-Calibrating Single Crystal Sapphire Optical Sensor Instrumentation for Accurate and Reliable Coal Gasifier Temperature Measurement'', funded by the Federal Energy Technology Center of the U.S. Department of Energy, and performed by the Center for Photonics Technology of the Bradley Department of Electrical and Computer Engineering at Virginia Tech. The outcome of the first phase of this program was the selection of broadband polarimetric differential interferometry (BPDI) for further prototype instrumentation development. This approach is based on the measurement of the optical path difference (OPD) between two orthogonally polarized light beams in a single-crystal sapphire disk. The objective of this program is to bring the BPDI sensor technology, which has already been demonstrated in the laboratory, to a level where the sensor can be deployed in the harsh industrial environments and will become commercially viable. Due to the difficulties described on the last report, field testing of the BPDI system has not continued to date. However, we have developed an alternative high temperature sensing solution, which is described in this report.

  1. On the temperature control in self-controlling hyperthermia therapy

    NASA Astrophysics Data System (ADS)

    Ebrahimi, Mahyar

    2016-10-01

    In self-controlling hyperthermia therapy, once the desired temperature is reached, the heat generation ceases and overheating is prevented. In order to design a system that generates sufficient heat without thermal ablation of surrounding healthy tissue, a good understanding of temperature distribution and its change with time is imperative. This study is conducted to extend our understanding about the heat generation and transfer, temperature distribution and temperature rise pattern in the tumor and surrounding tissue during self-controlling magnetic hyperthermia. A model consisting of two concentric spheres that represents the tumor and its surrounding tissue is considered and temperature change pattern and temperature distribution in tumor and surrounding tissue are studied. After describing the model and its governing equations and constants precisely, a typical numerical solution of the model is presented. Then it is showed that how different parameters like Curie temperature of nanoparticles, magnetic field amplitude and nanoparticles concentration can affect the temperature change pattern during self-controlling magnetic hyperthermia. The model system herein discussed can be useful to gain insight on the self-controlling magnetic hyperthermia while applied to cancer treatment in real scenario and can be useful for treatment strategy determination.

  2. Controlled-Temperature Hot-Air Gun

    NASA Technical Reports Server (NTRS)

    Munoz, M. C.

    1986-01-01

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

  3. Remote temperature-set-point controller

    DOEpatents

    Burke, William F.; Winiecki, Alan L.

    1986-01-01

    An instrument for carrying out mechanical strain tests on metallic samples with the addition of an electrical system for varying the temperature with strain, the instrument including opposing arms and associated equipment for holding a sample and varying the mechanical strain on the sample through a plurality of cycles of increasing and decreasing strain within predetermined limits, circuitry for producing an output signal representative of the strain during the tests, apparatus including a set point and a coil about the sample for providing a controlled temperature in the sample, and circuitry interconnected between the strain output signal and set point for varying the temperature of the sample linearly with strain during the tests.

  4. Multiphoton cryo microscope with sample temperature control

    NASA Astrophysics Data System (ADS)

    Breunig, H. G.; Uchugonova, A.; König, K.

    2013-02-01

    We present a multiphoton microscope system which combines the advantages of multiphoton imaging with precise control of the sample temperature. The microscope provides online insight in temperature-induced changes and effects in plant tissue and animal cells with subcellular resolution during cooling and thawing processes. Image contrast is based on multiphoton fluorescence intensity or fluorescence lifetime in the range from liquid nitrogen temperature up to +600°C. In addition, micro spectra from the imaged regions can be recorded. We present measurement results from plant leaf samples as well as Chinese hamster ovary cells.

  5. Optimization of a fluidic temperature control device

    NASA Technical Reports Server (NTRS)

    Zabsky, J. M.; Rask, D. R.; Starr, J. B.

    1970-01-01

    Refinements are described to an existing fluidic temperature control system developed under a prior study which modulated temperature at the inlet to the liquid-cooled garment by using existing liquid supply and return lines to transmit signals to a fluidic controller located in the spacecraft. This earlier system produced a limited range of garment inlet temperatures, requiring some bypassing of flow around the suit to make the astronaut comfortable at rest conditions. Refinements were based on a flow visualization study of the key element in the fluidic controller: the fluidic mixing valve. The valve's mixing-ratio range was achieved by making five key changes: (1) geometrical changes to the valve; (2) attenuation of noise generated in proportional amplifier cascades; (3) elimination of vortices at the exit of the fluidic mixing valve; (4) reduction of internal heat transfer; and (5) flow balancing through venting. As a result, the refined system is capable of modulating garment inlet temperature from 45 F to 70 F with a single manual control valve in series with the garment. This control valve signals without changing or bypassing flow through the garment.

  6. Feedwater temperature control methods and systems

    DOEpatents

    Moen, Stephan Craig; Noonan, Jack Patrick; Saha, Pradip

    2014-04-22

    A system for controlling the power level of a natural circulation boiling water nuclear reactor (NCBWR) is disclosed. The system, in accordance with an example embodiment of the present invention, may include a controller configured to control a power output level of the NCBWR by controlling a heating subsystem to adjust a temperature of feedwater flowing into an annulus of the NCBWR. The heating subsystem may include a steam diversion line configured to receive steam generated by a core of the NCBWR and a steam bypass valve configured to receive commands from the controller to control a flow of the steam in the steam diversion line, wherein the steam received by the steam diversion line has not passed through a turbine. Additional embodiments of the invention may include a feedwater bypass valve for controlling an amount of flow of the feedwater through a heater bypass line to the annulus.

  7. Advances in temperature derivative control and calorimetry

    SciTech Connect

    Hemmerich, J.L.; Loos, J.; Miller, A.; Milverton, P.

    1996-11-01

    Temperature stabilization by inertial feedback control has proven a powerful tool to create the ultrastable environment essential for high resolution calorimetry. A thermally insulated mass, connected to a base through Seebeck effect sensors (thermopiles) is used as a reference to control the base temperature. The thermopile signal is proportional to both the heat capacity of the reference mass and the derivative {dot {Theta}} of the base temperature {Theta}. Using vacuum insulation and bismuth telluride thermopiles, we designed and tested temperature derivative sensors (TDSs) with sensitivities up to 3300 VsK{sup {minus}1}. Standard industrial controllers with approximately {plus_minus}1 {mu}V input noise and stability, permit control of temperature derivatives to {plus_minus}3{times}10{sup {minus}10} Ks{sup {minus}1}. Single-cup thermoelectric calorimeters coupled to the TDS-controlled base permitted measurement of heat flow from samples in a power range from 3 {mu}W to 10 W with high accuracy ({plus_minus}100 ppm), resolution ({plus_minus}0.2 {mu}W), and reproducibility ({plus_minus}1 {mu}W). The design of two instruments is described in detail. Their performance is demonstrated on a variety of measurements, e.g., the determination of sample heat capacities with temperature ramp rates {dot {Theta}}={plus_minus}5{times}10{sup {minus}6} Ks{sup {minus}1}, the half-life of a 3 g tritium sample in a uranium getter bed, the decay heat of depleted uranium, and the heat evolution of epoxy resin. {copyright} {ital 1996 American Institute of Physics.}

  8. Low-Cost Programmed Oven Temperature Controller.

    ERIC Educational Resources Information Center

    Clubine, Gerald D.

    1982-01-01

    A remote, programed oven temperature controller unit was built for about $425.00. Specifications, circuit diagrams, design details, and operations are discussed. Detailed information including complete schematics, parts list, and detailed theory of operation may be obtained by contacting the author. (Author/SK)

  9. A temperature controller board for the ARC controller

    NASA Astrophysics Data System (ADS)

    Tulloch, Simon

    2016-07-01

    A high-performance temperature controller board has been produced for the ARC Generation-3 CCD controller. It contains two 9W temperature servo loops and four temperature input channels and is fully programmable via the ARC API and OWL data acquisition program. PI-loop control is implemented in an on-board micro. Both diode and RTD sensors can be used. Control and telemetry data is sent via the ARC backplane although a USB-2 interface is also available. Further functionality includes hardware timers and high current drivers for external shutters and calibration LEDs, an LCD display, a parallel i/o port, a pressure sensor interface and an uncommitted analogue telemetry input.

  10. ON-LINE SELF-CALIBRATING SINGLE CRYSTAL SAPPHIRE OPTICAL SENSOR INSTRUMENTATION FOR ACCURATE AND RELIABLE COAL GASIFIER TEMPERATURE MEASUREMENT

    SciTech Connect

    Kristie Cooper; Gary Pickrell; Anbo Wang

    2003-04-01

    This report summarizes technical progress over the first six months of the Phase II program ''On-Line Self-Calibrating Single Crystal Sapphire Optical Sensor Instrumentation for Accurate and Reliable Coal Gasifier Temperature Measurement'', funded by the Federal Energy Technology Center of the U.S. Department of Energy, and performed by the Center for Photonics Technology of the Bradley Department of Electrical and Computer Engineering at Virginia Tech. The outcome of the first phase of this program was the selection of broadband polarimetric differential interferometry (BPDI) for further prototype instrumentation development. This approach is based on the measurement of the optical path difference (OPD) between two orthogonally polarized light beams in a single-crystal sapphire disk. The objective of this program is to bring the BPDI sensor technology, which has already been demonstrated in the laboratory, to a level where the sensor can be deployed in the harsh industrial environments and will become commercially viable. Research efforts were focused on analyzing and testing factors that impact performance degradation of the initially designed sensor prototype, including sensing element movement within the sensing probe and optical signal quality degradation. Based these results, a new version of the sensing system was designed by combining the sapphire disk sensing element and the single crystal zirconia right angle light reflector into one novel single crystal sapphire right angle prism. The new sensor prototype was tested up to 1650 C.

  11. Observing Volcanic Thermal Anomalies from Space: How Accurate is the Estimation of the Hotspot's Size and Temperature?

    NASA Astrophysics Data System (ADS)

    Zaksek, K.; Pick, L.; Lombardo, V.; Hort, M. K.

    2015-12-01

    Measuring the heat emission from active volcanic features on the basis of infrared satellite images contributes to the volcano's hazard assessment. Because these thermal anomalies only occupy a small fraction (< 1 %) of a typically resolved target pixel (e.g. from Landsat 7, MODIS) the accurate determination of the hotspot's size and temperature is however problematic. Conventionally this is overcome by comparing observations in at least two separate infrared spectral wavebands (Dual-Band method). We investigate the resolution limits of this thermal un-mixing technique by means of a uniquely designed indoor analog experiment. Therein the volcanic feature is simulated by an electrical heating alloy of 0.5 mm diameter installed on a plywood panel of high emissivity. Two thermographic cameras (VarioCam high resolution and ImageIR 8300 by Infratec) record images of the artificial heat source in wavebands comparable to those available from satellite data. These range from the short-wave infrared (1.4-3 µm) over the mid-wave infrared (3-8 µm) to the thermal infrared (8-15 µm). In the conducted experiment the pixel fraction of the hotspot was successively reduced by increasing the camera-to-target distance from 3 m to 35 m. On the basis of an individual target pixel the expected decrease of the hotspot pixel area with distance at a relatively constant wire temperature of around 600 °C was confirmed. The deviation of the hotspot's pixel fraction yielded by the Dual-Band method from the theoretically calculated one was found to be within 20 % up until a target distance of 25 m. This means that a reliable estimation of the hotspot size is only possible if the hotspot is larger than about 3 % of the pixel area, a resolution boundary most remotely sensed volcanic hotspots fall below. Future efforts will focus on the investigation of a resolution limit for the hotspot's temperature by varying the alloy's amperage. Moreover, the un-mixing results for more realistic multi

  12. Accurate Modeling of Stability and Control Properties for Fighter Aircraft from CFD

    DTIC Science & Technology

    2012-03-01

    accurately placed and calibrated , etc. The results of the wind tunnel test must then be properly filtered and scaled to the proper size while taking...1 1.2 Background . . . . . . . . . . . . . . . . . . . . . . . . . 2 1.2.1 Wind Tunnel . . . . . . . . . . . . . . . . . . . 2...analysis, wind tunnel testing, flight testing, and Com- putational Fluid Dynamics (CFD). Analytical analysis includes linear aerodynamic techniques

  13. Remote temperature-set-point controller

    DOEpatents

    Burke, W.F.; Winiecki, A.L.

    1984-10-17

    An instrument is described for carrying out mechanical strain tests on metallic samples with the addition of means for varying the temperature with strain. The instrument includes opposing arms and associated equipment for holding a sample and varying the mechanical strain on the sample through a plurality of cycles of increasing and decreasing strain within predetermined limits, circuitry for producing an output signal representative of the strain during the tests, apparatus including a a set point and a coil about the sample for providing a controlled temperature in the sample, and circuitry interconnected between the strain output signal and set point for varying the temperature of the sample linearly with strain during the tests.

  14. Electric control of magnetism at room temperature.

    PubMed

    Wang, Liaoyu; Wang, Dunhui; Cao, Qingqi; Zheng, Yuanxia; Xuan, Haicheng; Gao, Jinlong; Du, Youwei

    2012-01-01

    In the single-phase multiferroics, the coupling between electric polarization (P) and magnetization (M) would enable the magnetoelectric (ME) effect, namely M induced and modulated by E, and conversely P by H. Especially, the manipulation of magnetization by an electric field at room-temperature is of great importance in technological applications, such as new information storage technology, four-state logic device, magnetoelectric sensors, low-power magnetoelectric device and so on. Furthermore, it can reduce power consumption and realize device miniaturization, which is very useful for the practical applications. In an M-type hexaferrite SrCo(2)Ti(2)Fe(8)O(19), large magnetization and electric polarization were observed simultaneously at room-temperature. Moreover, large effect of electric field-controlled magnetization was observed even without magnetic bias field. These results illuminate a promising potential to apply in magnetoelectric devices at room temperature and imply plentiful physics behind them.

  15. Electric control of magnetism at room temperature

    PubMed Central

    Wang, Liaoyu; Wang, Dunhui; Cao, Qingqi; Zheng, Yuanxia; Xuan, Haicheng; Gao, Jinlong; Du, Youwei

    2012-01-01

    In the single-phase multiferroics, the coupling between electric polarization (P) and magnetization (M) would enable the magnetoelectric (ME) effect, namely M induced and modulated by E, and conversely P by H. Especially, the manipulation of magnetization by an electric field at room-temperature is of great importance in technological applications, such as new information storage technology, four-state logic device, magnetoelectric sensors, low-power magnetoelectric device and so on. Furthermore, it can reduce power consumption and realize device miniaturization, which is very useful for the practical applications. In an M-type hexaferrite SrCo2Ti2Fe8O19, large magnetization and electric polarization were observed simultaneously at room-temperature. Moreover, large effect of electric field-controlled magnetization was observed even without magnetic bias field. These results illuminate a promising potential to apply in magnetoelectric devices at room temperature and imply plentiful physics behind them. PMID:22355737

  16. Mine operating accurate stability control with optical fiber sensing and Bragg grating technology: the BRITE-EURAM STABILOS project

    NASA Astrophysics Data System (ADS)

    Ferdinand, Pierre; Ferragu, Olivier; Lechien, J. L.; Lescop, B.; Marty-DeWinter, Veronique; Rougeault, S.; Pierre, Guillaume; Renouf, C.; Jarret, Bertrand; Kotrotsios, Georges; Neuman, Victor; Depeursinge, Y.; Michel, J. B.; Van Uffelen, M.; Verbandt, Yves; Voet, Marc R. H.; Toscano, D.

    1994-09-01

    Recent developments of stability control in mines, essentially based on Ge-doped Fiber Bragg Gratings (FBG) are reported including results about the different aspects of the system: accurate characterizations of FBG, sensor network topology and multiplexing method, user interface design and sensor packaging.

  17. Temperature-Control Apparatus For Hydrogen Maser

    NASA Technical Reports Server (NTRS)

    Vessot, R. F. C.; Mattison, E. M.

    1994-01-01

    Thermal-control apparatus maintains hydrogen maser at nearly constant temperature during long-term operational test. Designed to maintain, in small cylindrical vacuum tank containing maser, nearly isothermal condition when test conducted in air. Provides approximation of more nearly isothermal condition expected to be maintained in intended application, in which maser operated in vacuum environment and losses of heat reduced further by multilayer reflective insulation.

  18. Reaction temperature sensing (RTS)-based control for Li-ion battery safety

    PubMed Central

    Zhang, Guangsheng; Cao, Lei; Ge, Shanhai; Wang, Chao-Yang; Shaffer, Christian E.; Rahn, Christopher D.

    2015-01-01

    We report reaction temperature sensing (RTS)-based control to fundamentally enhance Li-ion battery safety. RTS placed at the electrochemical interface inside a Li-ion cell is shown to detect temperature rise much faster and more accurately than external measurement of cell surface temperature. We demonstrate, for the first time, that RTS-based control shuts down a dangerous short-circuit event 3 times earlier than surface temperature- based control and prevents cell overheating by 50 °C and the resultant cell damage. PMID:26658957

  19. Reaction temperature sensing (RTS)-based control for Li-ion battery safety.

    PubMed

    Zhang, Guangsheng; Cao, Lei; Ge, Shanhai; Wang, Chao-Yang; Shaffer, Christian E; Rahn, Christopher D

    2015-12-11

    We report reaction temperature sensing (RTS)-based control to fundamentally enhance Li-ion battery safety. RTS placed at the electrochemical interface inside a Li-ion cell is shown to detect temperature rise much faster and more accurately than external measurement of cell surface temperature. We demonstrate, for the first time, that RTS-based control shuts down a dangerous short-circuit event 3 times earlier than surface temperature- based control and prevents cell overheating by 50 °C and the resultant cell damage.

  20. Reaction temperature sensing (RTS)-based control for Li-ion battery safety

    NASA Astrophysics Data System (ADS)

    Zhang, Guangsheng; Cao, Lei; Ge, Shanhai; Wang, Chao-Yang; Shaffer, Christian E.; Rahn, Christopher D.

    2015-12-01

    We report reaction temperature sensing (RTS)-based control to fundamentally enhance Li-ion battery safety. RTS placed at the electrochemical interface inside a Li-ion cell is shown to detect temperature rise much faster and more accurately than external measurement of cell surface temperature. We demonstrate, for the first time, that RTS-based control shuts down a dangerous short-circuit event 3 times earlier than surface temperature- based control and prevents cell overheating by 50 °C and the resultant cell damage.

  1. 21 CFR 870.4250 - Cardiopulmonary bypass temperature controller.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Cardiopulmonary bypass temperature controller. 870... Cardiopulmonary bypass temperature controller. (a) Identification. A cardiopulmonary bypass temperature controller is a device used to control the temperature of the fluid entering and leaving a heat exchanger....

  2. 21 CFR 870.4250 - Cardiopulmonary bypass temperature controller.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Cardiopulmonary bypass temperature controller. 870... Cardiopulmonary bypass temperature controller. (a) Identification. A cardiopulmonary bypass temperature controller is a device used to control the temperature of the fluid entering and leaving a heat exchanger....

  3. 21 CFR 870.4250 - Cardiopulmonary bypass temperature controller.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Cardiopulmonary bypass temperature controller. 870... Cardiopulmonary bypass temperature controller. (a) Identification. A cardiopulmonary bypass temperature controller is a device used to control the temperature of the fluid entering and leaving a heat exchanger....

  4. 21 CFR 870.4250 - Cardiopulmonary bypass temperature controller.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Cardiopulmonary bypass temperature controller. 870... Cardiopulmonary bypass temperature controller. (a) Identification. A cardiopulmonary bypass temperature controller is a device used to control the temperature of the fluid entering and leaving a heat exchanger....

  5. 21 CFR 870.4250 - Cardiopulmonary bypass temperature controller.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Cardiopulmonary bypass temperature controller. 870... Cardiopulmonary bypass temperature controller. (a) Identification. A cardiopulmonary bypass temperature controller is a device used to control the temperature of the fluid entering and leaving a heat exchanger....

  6. Quantum Brachistochrone Curves as Geodesics: Obtaining Accurate Minimum-Time Protocols for the Control of Quantum Systems

    NASA Astrophysics Data System (ADS)

    Wang, Xiaoting; Allegra, Michele; Jacobs, Kurt; Lloyd, Seth; Lupo, Cosmo; Mohseni, Masoud

    2015-05-01

    Most methods of optimal control cannot obtain accurate time-optimal protocols. The quantum brachistochrone equation is an exception, and has the potential to provide accurate time-optimal protocols for a wide range of quantum control problems. So far, this potential has not been realized, however, due to the inadequacy of conventional numerical methods to solve it. Here we show that the quantum brachistochrone problem can be recast as that of finding geodesic paths in the space of unitary operators. We expect this brachistochrone-geodesic connection to have broad applications, as it opens up minimal-time control to the tools of geometry. As one such application, we use it to obtain a fast numerical method to solve the brachistochrone problem, and apply this method to two examples demonstrating its power.

  7. Tuning-free controller to accurately regulate flow rates in a microfluidic network

    PubMed Central

    Heo, Young Jin; Kang, Junsu; Kim, Min Jun; Chung, Wan Kyun

    2016-01-01

    We describe a control algorithm that can improve accuracy and stability of flow regulation in a microfluidic network that uses a conventional pressure pump system. The algorithm enables simultaneous and independent control of fluid flows in multiple micro-channels of a microfluidic network, but does not require any model parameters or tuning process. We investigate robustness and optimality of the proposed control algorithm and those are verified by simulations and experiments. In addition, the control algorithm is compared with a conventional PID controller to show that the proposed control algorithm resolves critical problems induced by the PID control. The capability of the control algorithm can be used not only in high-precision flow regulation in the presence of disturbance, but in some useful functions for lab-on-a-chip devices such as regulation of volumetric flow rate, interface position control of two laminar flows, valveless flow switching, droplet generation and particle manipulation. We demonstrate those functions and also suggest further potential biological applications which can be accomplished by the proposed control framework. PMID:26987587

  8. Tuning-free controller to accurately regulate flow rates in a microfluidic network

    NASA Astrophysics Data System (ADS)

    Heo, Young Jin; Kang, Junsu; Kim, Min Jun; Chung, Wan Kyun

    2016-03-01

    We describe a control algorithm that can improve accuracy and stability of flow regulation in a microfluidic network that uses a conventional pressure pump system. The algorithm enables simultaneous and independent control of fluid flows in multiple micro-channels of a microfluidic network, but does not require any model parameters or tuning process. We investigate robustness and optimality of the proposed control algorithm and those are verified by simulations and experiments. In addition, the control algorithm is compared with a conventional PID controller to show that the proposed control algorithm resolves critical problems induced by the PID control. The capability of the control algorithm can be used not only in high-precision flow regulation in the presence of disturbance, but in some useful functions for lab-on-a-chip devices such as regulation of volumetric flow rate, interface position control of two laminar flows, valveless flow switching, droplet generation and particle manipulation. We demonstrate those functions and also suggest further potential biological applications which can be accomplished by the proposed control framework.

  9. Tuning-free controller to accurately regulate flow rates in a microfluidic network.

    PubMed

    Heo, Young Jin; Kang, Junsu; Kim, Min Jun; Chung, Wan Kyun

    2016-03-18

    We describe a control algorithm that can improve accuracy and stability of flow regulation in a microfluidic network that uses a conventional pressure pump system. The algorithm enables simultaneous and independent control of fluid flows in multiple micro-channels of a microfluidic network, but does not require any model parameters or tuning process. We investigate robustness and optimality of the proposed control algorithm and those are verified by simulations and experiments. In addition, the control algorithm is compared with a conventional PID controller to show that the proposed control algorithm resolves critical problems induced by the PID control. The capability of the control algorithm can be used not only in high-precision flow regulation in the presence of disturbance, but in some useful functions for lab-on-a-chip devices such as regulation of volumetric flow rate, interface position control of two laminar flows, valveless flow switching, droplet generation and particle manipulation. We demonstrate those functions and also suggest further potential biological applications which can be accomplished by the proposed control framework.

  10. Adaptive fuzzy PID temperature control system based on single-chip computer for the autoclave

    NASA Astrophysics Data System (ADS)

    Zhang, F.; Wang, J.; Fu, S. L.; He, Z. T.; Li, X. P.

    2008-12-01

    The autoclave is one of main preparation equipments of crystal preparation by hydrothermal method. The preparation temperature will seriously influence crystals quality and crystals size at high temperature, how to measure and control precisely the autoclave temperature can be of real significance. The characteristic of hysteresis, nonlinearity and difficulty to acquire the precise mathematical model existing in the temperature control of the autoclave was researched. The general PID controller adopted usually in the autoclave temperature control system is hard to improve temperature control performance. Based on the advantages of fuzzy controller that does not depend on the precise mathematical model and the stabilization of PID controller, single-chip computer integrated fuzzy PID control algorithm is adopted, and the temperature system is designed, the foundational working principle was discussed. The control system includes SCM (AT89C52), temperature sensor, A/D converter circuit and corresponding circuit and interface, can make the autoclave temperature measure and control accurately. The system hardware includes main circuit, thyristor drive circuit, audible and visual alarm circuit, watchdog circuit, clock circuit, keyboard and display circuit so on, which can achieve gathering, analyzing, comparing and controlling the autoclave temperature parameter. The program of control system includes the treatment and collection of temperature data, the dynamic display program, the fuzzy PID control system, the audible and visual alarm program, et al, and the system's main software, which includes initialization, key-press processing, input processing, display, and the fuzzy PID control program was analyzed. The results showed that the fuzzy PID control system makes the adjustment time of temperature decreased and the precision of temperature control improved, the quality and the crystals size of the preparation crystals can achieve the expect experiment results.

  11. On controllability of thermocapillary instability by local temperature control

    NASA Astrophysics Data System (ADS)

    Shiomi, Junichiro

    Thermally nonequilibrium liquid processing and experiments in microgravity or microscale of-ten suffer from dominant thermocapillary convection and its instability. While the instability can be utilized to promote mixing, there are certainly situations where it is desirable to atten-uate the fluid motion. Here, we theoretically investigate the possibility to control the unstable thermocapillary convection by taking a simple model system, i.e. a liquid-filled open cavity. The system is closely related to the liquid bridge and annular systems, which have been investi-gated extensively over the last few decades, being motivated by the crystal growth application. Such system is suitable for flow control target since they usually have strong mode selectivity, and hence, the observability and controllability can be satisfied by small number of controllers. In addition, since the convection is driven by the temperature distribution at the free surface, the entire flow field can be influenced by perturbing the scalar quantity (temperature). Fur-thermore, the relatively slow timescales of the phenomena (e.g. compared with turbulent flow) allow us to apply advanced real-time control laws. The author and coworkers have demon-strated the possibility of stabilizing the convective instability by applying mode-selective linear and weakly nonlinear feedback control schemes with only a few pairs of local temperature sen-sors and actuators (heaters) [1]. In this work, with an aim to develop a practical control scheme that is applicable to various degrees of nonlinearity and number of modes, an optimal control problem has been formulated. Based on the reduced toy model of the open cavity system [2] with 6 oscillatory modes, the linear optimal control was applied with only 2 actuators. The performance of the control was quantified for different strengths of nonlinearity. Dependences of the control performance on the actuator position and size were also investigated. The result shows

  12. Solar energy control system. [temperature measurement

    NASA Technical Reports Server (NTRS)

    Currie, J. R. (Inventor)

    1981-01-01

    A solar energy control system for a hot air type solar energy heating system wherein thermocouples are arranged to sense the temperature of a solar collector, a space to be heated, and a top and bottom of a heat storage unit is disclosed. Pertinent thermocouples are differentially connected together, and these are employed to effect the operation of dampers, a fan, and an auxiliary heat source. In accomplishing this, the differential outputs from the thermocouples are amplified by a single amplifier by multiplexing techniques. Additionally, the amplifier is corrected as to offset by including as one multiplex channel a common reference signal.

  13. Myoelectric neural interface enables accurate control of a virtual multiple degree-of-freedom foot-ankle prosthesis.

    PubMed

    Tkach, D C; Lipschutz, R D; Finucane, S B; Hargrove, L J

    2013-06-01

    Technological advances have enabled clinical use of powered foot-ankle prostheses. Although the fundamental purposes of such devices are to restore natural gait and reduce energy expenditure by amputees during walking, these powered prostheses enable further restoration of ankle function through possible voluntary control of the powered joints. Such control would greatly assist amputees in daily tasks such as reaching, dressing, or simple limb repositioning for comfort. A myoelectric interface between an amputee and the powered foot-ankle prostheses may provide the required control signals for accurate control of multiple degrees of freedom of the ankle joint. Using a pattern recognition classifier we compared the error rates of predicting up to 7 different ankle-joint movements using electromyographic (EMG) signals collected from below-knee, as well as below-knee combined with above-knee muscles of 12 trans-tibial amputee and 5 control subjects. Our findings suggest very accurate (5.3 ± 0.5%SE mean error) real-time control of a 1 degree of freedom (DOF) of ankle joint can be achieved by amputees using EMG from as few as 4 below-knee muscles. Reliable control (9.8 ± 0.7%SE mean error) of 3 DOFs can be achieved using EMG from 8 below-knee and above-knee muscles.

  14. Apparatus for use in rapid and accurate controlled-potential coulometric analysis

    DOEpatents

    Frazzini, Thomas L.; Holland, Michael K.; Pietri, Charles E.; Weiss, Jon R.

    1981-01-01

    An apparatus for controlled-potential coulometric analysis of a solution includes a cell to contain the solution to be analyzed and a plurality of electrodes to contact the solution in the cell. Means are provided to stir the solution and to control the atmosphere above it. A potentiostat connected to the electrodes controls potential differences among the electrodes. An electronic circuit connected to the potentiostat provides analog-to-digital conversion and displays a precise count of charge transfer during a desired chemical process. This count provides a measure of the amount of an unknown substance in the solution.

  15. A Polymer Visualization System with Accurate Heating and Cooling Control and High-Speed Imaging

    PubMed Central

    Wong, Anson; Guo, Yanting; Park, Chul B.; Zhou, Nan Q.

    2015-01-01

    A visualization system to observe crystal and bubble formation in polymers under high temperature and pressure has been developed. Using this system, polymer can be subjected to a programmable thermal treatment to simulate the process in high pressure differential scanning calorimetry (HPDSC). With a high-temperature/high-pressure view-cell unit, this system enables in situ observation of crystal formation in semi-crystalline polymers to complement thermal analyses with HPDSC. The high-speed recording capability of the camera not only allows detailed recording of crystal formation, it also enables in situ capture of plastic foaming processes with a high temporal resolution. To demonstrate the system’s capability, crystal formation and foaming processes of polypropylene/carbon dioxide systems were examined. It was observed that crystals nucleated and grew into spherulites, and they grew at faster rates as temperature decreased. This observation agrees with the crystallinity measurement obtained with the HPDSC. Cell nucleation first occurred at crystals’ boundaries due to CO2 exclusion from crystal growth fronts. Subsequently, cells were nucleated around the existing ones due to tensile stresses generated in the constrained amorphous regions between networks of crystals. PMID:25915031

  16. Procedure for computer-controlled milling of accurate surfaces of revolution for millimeter and far-infrared mirrors

    NASA Technical Reports Server (NTRS)

    Emmons, Louisa; De Zafra, Robert

    1991-01-01

    A simple method for milling accurate off-axis parabolic mirrors with a computer-controlled milling machine is discussed. For machines with a built-in circle-cutting routine, an exact paraboloid can be milled with few computer commands and without the use of the spherical or linear approximations. The proposed method can be adapted easily to cut off-axis sections of elliptical or spherical mirrors.

  17. Precision Pointing Control to and Accurate Target Estimation of a Non-Cooperative Vehicle

    NASA Technical Reports Server (NTRS)

    VanEepoel, John; Thienel, Julie; Sanner, Robert M.

    2006-01-01

    In 2004, NASA began investigating a robotic servicing mission for the Hubble Space Telescope (HST). Such a mission would not only require estimates of the HST attitude and rates in order to achieve capture by the proposed Hubble Robotic Vehicle (HRV), but also precision control to achieve the desired rate and maintain the orientation to successfully dock with HST. To generalize the situation, HST is the target vehicle and HRV is the chaser. This work presents a nonlinear approach for estimating the body rates of a non-cooperative target vehicle, and coupling this estimation to a control scheme. Non-cooperative in this context relates to the target vehicle no longer having the ability to maintain attitude control or transmit attitude knowledge.

  18. 14 CFR 23.1157 - Carburetor air temperature controls.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

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

  19. 14 CFR 23.1157 - Carburetor air temperature controls.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

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

  20. 14 CFR 23.1157 - Carburetor air temperature controls.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

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

  1. 14 CFR 23.1157 - Carburetor air temperature controls.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

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

  2. 14 CFR 23.1157 - Carburetor air temperature controls.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

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

  3. Intestinal ferritin H is required for an accurate control of iron absorption.

    PubMed

    Vanoaica, Liviu; Darshan, Deepak; Richman, Larry; Schümann, Klaus; Kühn, Lukas C

    2010-09-08

    To maintain appropriate body iron levels, iron absorption by the proximal duodenum is thought to be controlled by hepcidin, a polypeptide secreted by hepatocytes in response to high serum iron. Hepcidin limits basolateral iron efflux from the duodenal epithelium by binding and downregulating the intestinal iron exporter ferroportin. Here, we found that mice with an intestinal ferritin H gene deletion show increased body iron stores and transferrin saturation. As expected for iron-loaded animals, the ferritin H-deleted mice showed induced liver hepcidin mRNA levels and reduced duodenal expression of DMT1 and DcytB mRNA. In spite of these feedback controls, intestinal ferroportin protein and (59)Fe absorption were increased more than 2-fold in the deleted mice. Our results demonstrate that hepcidin-mediated regulation alone is insufficient to restrict iron absorption and that intestinal ferritin H is also required to limit iron efflux from intestinal cells.

  4. Accurate liability estimation improves power in ascertained case-control studies.

    PubMed

    Weissbrod, Omer; Lippert, Christoph; Geiger, Dan; Heckerman, David

    2015-04-01

    Linear mixed models (LMMs) have emerged as the method of choice for confounded genome-wide association studies. However, the performance of LMMs in nonrandomly ascertained case-control studies deteriorates with increasing sample size. We propose a framework called LEAP (liability estimator as a phenotype; https://github.com/omerwe/LEAP) that tests for association with estimated latent values corresponding to severity of phenotype, and we demonstrate that this can lead to a substantial power increase.

  5. [Pharmacological approaches to control of body temperature].

    PubMed

    Soto Ruiz, M Nelia; Ezquerro Rodríguez, Esther; Marín Fernández, Blanca

    2012-05-01

    The main antipyretic drugs belong to two different therapeutic groups: non-steroidal anti-inflammatory and antirheumatic; and analgesic and antipyretic. In some cases, both groups are included in the NSAID group (analgesics antipyretics and NSAID). Most of the chemical compounds included in this group have three actions, but the relative performance of each of them can be different, as well as the incidence of adverse effects. For this reason its clinical use will depend on effectiveness and relative toxicity. When there is fever, NSAID normalizes the action of the thermoregulatory center in the hypothalamus, decreasing production of prostaglandins by inhibiting enzymes cyclooxygenase. But not all are capable of controlling the temperature which increases in adaptative physiological situations, as in heat stroke, intense exercise or by increasing the temperature. The classification is based on chemical characteristics and can be grouped into nine classes: 1) Salicylates, 2) Para-aminophenol derivatives, 3) Derivatives of pyrazolone, 4) Acetic acid derivatives, 5) Derivatives propionic acid, 6) Anthranilic derivatives, 7) Oxicam derivatives, 8) COX-2 inhibitors, 9) Other NSAID. This article describes the indications, mechanism of action, clinical presentation, routes of administration, adverse reactions, contraindications, precautions and drug interactions of the most commonly used (Derivatives of Salicylic Acid, Paracetamol, Metamizole, Ibuprofen, Drantoleno).

  6. Temperature-Controlled Clamping and Releasing Mechanism

    NASA Technical Reports Server (NTRS)

    Rosing, David; Ford, Virginia

    2005-01-01

    A report describes the development of a mechanism that automatically clamps upon warming and releases upon cooling between temperature limits of approx. =180 K and approx. =293 K. The mechanism satisfied a need specific to a program that involved repeated excursions of a spectrometer between a room-temperature atmospheric environment and a cryogenic vacuum testing environment. The mechanism was also to be utilized in the intended application of the spectrometer, in which the spectrometer would be clamped for protection during launch of a spacecraft and released in the cold of outer space to allow it to assume its nominal configuration for scientific observations. The mechanism is passive in the sense that its operation does not depend on a control system and does not require any power other than that incidental to heating and cooling. The clamping and releasing action is effected by bolt-preloaded stacks of shape-memory-alloy (SMA) cylinders. In designing this mechanism, as in designing other, similar SMA mechanisms, it was necessary to account for the complex interplay among thermal expansion, elastic and inelastic deformation under load, and SMA thermomechanical properties.

  7. Are tidal volume measurements in neonatal pressure-controlled ventilation accurate?

    PubMed

    Chow, Lily C; Vanderhal, Andre; Raber, Jorge; Sola, Augusto

    2002-09-01

    Bedside pulmonary mechanics monitors (PMM) have become useful in ventilatory management in neonates. These monitors are used more frequently due to recent improvements in data-processing capabilities. PMM devices are often part of the ventilator or are separate units. The accuracy and reliability of these systems have not been carefully evaluated. We compared a single ventilatory parameter, tidal volume (V(t)), as measured by several systems. We looked at two freestanding PMMs: the Ventrak Respiratory Monitoring System (Novametrix, Wallingford, CT) and the Bicore CP-100 Neonatal Pulmonary Monitor (Allied Health Care Products, Riverside, CA), and three ventilators with built-in PMM: the VIP Bird Ventilator (Bird Products Corp., Palm Springs, CA), Siemens Servo 300A (Siemens-Elema AB, Solna, Sweden), and Drager Babylog 8000 (Drager, Inc., Chantilly, VA). A calibrated syringe (Hans Rudolph, Inc., Kansas City, MO) was used to deliver tidal volumes of 4, 10, and 20 mL to each ventilator system coupled with a freestanding PMM. After achieving steady state, six consecutive V(t) readings were taken simultaneously from the freestanding PMM and each ventilator. In a second portion of the bench study, we used pressure-control ventilation and measured exhaled tidal volume (V(te)) while ventilating a Bear Test Lung with the same three ventilators. We adjusted peak inspiratory pressure (PIP) under controlled conditions to achieve the three different targeted tidal volumes on the paired freestanding PMM. Again, six V(te) measurements were recorded for each tidal volume. Means and standard deviations were calculated.The percentage difference in measurement of V(t) delivered by calibrated syringe varied greatly, with the greatest discrepancy seen in the smallest tidal volumes, by up to 28%. In pressure control mode, V(te) as measured by the Siemens was significantly overestimated by 20-95%, with the biggest discrepancy at the smallest V(te), particularly when paired with the Bicore

  8. A long time low drift integrator with temperature control.

    PubMed

    Zhang, Donglai; Yan, Xiaolan; Zhang, Enchao; Pan, Shimin

    2016-10-01

    The output of an operational amplifier always contains signals that could not have been predicted, even with knowledge of the input and an accurately determined closed-loop transfer function. These signals lead to integrator zero-drift over time. A new type of integrator system with a long-term low-drift characteristic has therefore been designed. The integrator system is composed of a temperature control module and an integrator module. The aluminum printed circuit board of the integrator is glued to a thermoelectric cooler to maintain the electronic components at a stable temperature. The integration drift is automatically compensated using an analog-to-digital converter/proportional integration/digital-to-analog converter control circuit. Performance testing in a standard magnet shows that the proposed integrator, which has an integration time constant of 10 ms, has a low integration drift (<5 mV) over 1000 s after repeated measurements. The integrator can be used for magnetic flux measurements in most tokamaks and in the wire rope nondestructive test.

  9. A long time low drift integrator with temperature control

    NASA Astrophysics Data System (ADS)

    Zhang, Donglai; Yan, Xiaolan; Zhang, Enchao; Pan, Shimin

    2016-10-01

    The output of an operational amplifier always contains signals that could not have been predicted, even with knowledge of the input and an accurately determined closed-loop transfer function. These signals lead to integrator zero-drift over time. A new type of integrator system with a long-term low-drift characteristic has therefore been designed. The integrator system is composed of a temperature control module and an integrator module. The aluminum printed circuit board of the integrator is glued to a thermoelectric cooler to maintain the electronic components at a stable temperature. The integration drift is automatically compensated using an analog-to-digital converter/proportional integration/digital-to-analog converter control circuit. Performance testing in a standard magnet shows that the proposed integrator, which has an integration time constant of 10 ms, has a low integration drift (<5 mV) over 1000 s after repeated measurements. The integrator can be used for magnetic flux measurements in most tokamaks and in the wire rope nondestructive test.

  10. A comparative design view for accurate control of servos using a field programmable gate array

    NASA Astrophysics Data System (ADS)

    Tickle, A. J.; Harvey, P. K.; Wu, F.; Buckle, J. R.; Smith, J. S.

    2009-07-01

    An embedded system is a special-purpose computer system designed to perform one or a few dedicated functions. Altera DSP Builder presents designers and users with an alternate approach when creating their systems by employing a blockset similar to that already used in Simulink. The application considered in this paper is the design of a Pulse Width Modulation (PWM) system for use in stereo vision. PWM can replace a digital-to-analogue converter to control audio speakers, LED intensity, motor speed, and servo position. Rather than the conventional HDL coding approach this Simulink approach provides an easy understanding platform to the PWM design. This paper includes a comparison between two approaches regarding resource usage and flexibility etc. Included is how DSP Builder manipulates an onboard clock signal, in order to create the control pulses to the "raw" coding of a PWM generator in VHDL. Both methods were shown to a selection of people and their views on which version they would subsequently use in their relative fields is discussed.

  11. Smart building temperature control using occupant feedback

    NASA Astrophysics Data System (ADS)

    Gupta, Santosh K.

    This work was motivated by the problem of computing optimal commonly-agreeable thermal settings in spaces with multiple occupants. In this work we propose algorithms that take into account each occupant's preferences along with the thermal correlations between different zones in a building, to arrive at optimal thermal settings for all zones of the building in a coordinated manner. In the first part of this work we incorporate active occupant feedback to minimize aggregate user discomfort and total energy cost. User feedback is used to estimate the users comfort range, taking into account possible inaccuracies in the feedback. The control algorithm takes the energy cost into account, trading it off optimally with the aggregate user discomfort. A lumped heat transfer model based on thermal resistance and capacitance is used to model a multi-zone building. We provide a stability analysis and establish convergence of the proposed solution to a desired temperature that minimizes the sum of energy cost and aggregate user discomfort. However, for convergence to the optimal, sufficient separation between the user feedback frequency and the dynamics of the system is necessary; otherwise, the user feedback provided do not correctly reflect the effect of current control input value on user discomfort. The algorithm is further extended using singular perturbation theory to determine the minimum time between successive user feedback solicitations. Under sufficient time scale separation, we establish convergence of the proposed solution. Simulation study and experimental runs on the Watervliet based test facility demonstrates performance of the algorithm. In the second part we develop a consensus algorithm for attaining a common temperature set-point that is agreeable to all occupants of a zone in a typical multi-occupant space. The information on the comfort range functions is indeed held privately by each occupant. Using occupant differentiated dynamically adjusted prices as

  12. Compact and cost-effective temperature-insensitive bio-sensor based on long-period fiber gratings for accurate detection of E. coli bacteria in water.

    PubMed

    Dandapat, Krishnendu; Tripathi, Saurabh Mani; Chinifooroshan, Yasser; Bock, Wojtek J; Mikulic, Predrag

    2016-09-15

    We propose and demonstrate a novel temperature-insensitive bio-sensor for accurate and quantitative detection of Escherichia coli (E. coli) bacteria in water. Surface sensitivity is maximized by operating the long-period fiber grating (LPFG) closest to its turnaround wavelength, and the temperature insensitivity is achieved by selectively exciting a pair of cladding modes with opposite dispersion characteristics. Our sensor shows a nominal temperature sensitivity of ∼1.25  pm/°C, which can be further reduced by properly adjusting the LPFG lengths, while maintaining a high refractive index sensitivity of 1929 nm/RIU. The overall length of the sensor is ∼3.6  cm, making it ideally suitable for bio-sensing applications. As an example, we also show the sensor's capability for reliable, quantitative detection of E. coli bacteria in water over a temperature fluctuation of room temperature to 40°C.

  13. Fuel processor temperature monitoring and control

    DOEpatents

    Keskula, Donald H.; Doan, Tien M.; Clingerman, Bruce J.

    2002-01-01

    In one embodiment, the method of the invention monitors one or more of the following conditions: a relatively low temperature value of the gas stream; a relatively high temperature value of the gas stream; and a rate-of-change of monitored temperature. In a preferred embodiment, the rate of temperature change is monitored to prevent the occurrence of an unacceptably high or low temperature condition. Here, at least two temperatures of the recirculating gas stream are monitored over a period of time. The rate-of-change of temperature versus time is determined. Then the monitored rate-of-change of temperature is compared to a preselected rate-of-change of value. The monitoring of rate-of-change of temperature provides proactive means for preventing occurrence of an unacceptably high temperature in the catalytic reactor.

  14. Device for self-verifying temperature measurement and control

    DOEpatents

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

    2004-08-03

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

  15. Parasitic load control system for exhaust temperature control

    DOEpatents

    Strauser, Aaron D.; Coleman, Gerald N.; Coldren, Dana R.

    2009-04-28

    A parasitic load control system is provided. The system may include an exhaust producing engine and a fuel pumping mechanism configured to pressurize fuel in a pressure chamber. The system may also include an injection valve configured to cause fuel pressure to build within the pressure chamber when in a first position and allow injection of fuel from the pressure chamber into one or more combustion chambers of the engine when in a second position. The system may further include a controller configured to independently regulate the pressure in the pressure chamber and the injection of fuel into the one or more combustion chambers, to increase a load on the fuel pumping mechanism, increasing parasitic load on the engine, thereby increasing a temperature of the exhaust produced by the engine.

  16. 30 CFR 77.314 - Automatic temperature control instruments.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Automatic temperature control instruments. 77... UNDERGROUND COAL MINES Thermal Dryers § 77.314 Automatic temperature control instruments. (a) Automatic temperature control instruments for thermal dryer system shall be of the recording type. (b)...

  17. 30 CFR 77.314 - Automatic temperature control instruments.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Automatic temperature control instruments. 77... UNDERGROUND COAL MINES Thermal Dryers § 77.314 Automatic temperature control instruments. (a) Automatic temperature control instruments for thermal dryer system shall be of the recording type. (b)...

  18. 30 CFR 77.314 - Automatic temperature control instruments.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Automatic temperature control instruments. 77... UNDERGROUND COAL MINES Thermal Dryers § 77.314 Automatic temperature control instruments. (a) Automatic temperature control instruments for thermal dryer system shall be of the recording type. (b)...

  19. 30 CFR 77.314 - Automatic temperature control instruments.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Automatic temperature control instruments. 77... UNDERGROUND COAL MINES Thermal Dryers § 77.314 Automatic temperature control instruments. (a) Automatic temperature control instruments for thermal dryer system shall be of the recording type. (b)...

  20. 30 CFR 77.314 - Automatic temperature control instruments.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Automatic temperature control instruments. 77... UNDERGROUND COAL MINES Thermal Dryers § 77.314 Automatic temperature control instruments. (a) Automatic temperature control instruments for thermal dryer system shall be of the recording type. (b)...

  1. [Physical methods used to control body temperature].

    PubMed

    Ezquerro Rodríguez, Esther; Montes García, Yolanda; Marín Fernández, Blanca

    2012-10-01

    The physical methods to control body temperature, either to induce hypothermia, or to increase body temperature, can be of two types: physical methods of external heating or cooling and invasive methods that require complex procedures and technology. There are many strategies for the induction of hypothermia, all based on three of the four basic mechanisms of heat transfer, evaporation, convection and conduction. In the hospital environment the external cooling methods or surface (blankets of cold air or water circulation, plates of hydrogel Artic Sun, methods of cooling helmet) are the most widely used for the induction of therapeutic hypothermia. The most non-invasive devices used are blades of hydrogel, which use water conduction high speed between the layers of pads. But there are quicker methods to induce hypothermia; i.e., invasive methods of internal cooling: infusion of intravenous crystalloid; endovascular catheters located in a central vein through which flows saline pumped by a closed circuit; By-pass cardio-pulmonary with extracorporeal circulation; and By-pass percutaneous venous system for continuous hemofiltration. The average physical external heating is based on the patient's ability to produce and retain heat or in the application of heat to the body surface of the patient (hot spring baths with hot water, air blankets, blankets of water). But when the answer to these methods are not sufficient or hypothermia is moderate or severe, other methods of internal heat are suggested: inhalation of oxygen or warm to 40-45 degrees C and wet by facial mask or endotracheal tube; intravenous (IV) infusion with hot solutions; Irrigation of body cavities with warm saline solution to 40-42 degrees C; peritoneal dialysis, haemodialysis and hemofiltration; Continuous reheating arterio-venous or venous-venous; extracorporeal circulation with cardiopulmonary bypass. In this article each of the methods listed above will be described for the induction of hypothermia

  2. Transcutaneous temperature controlled radiofrequency for orgasmic dysfunction

    PubMed Central

    2016-01-01

    Background and Objectives To evaluate the safety, tolerability, and clinical efficacy of transcutaneous temperature controlled radiofrequency (TTCRF) on vulvovaginal tissue for orgasmic dysfunction. Study Design/Materials and Methods Subjects included 25 sexually active women, ages 21–65, with self‐reported difficulty in achieving orgasms during sex (anorgasmic or slow‐to‐orgasm). Each patient received three sessions at intervals of about 1 month. Treatment was performed using a slim S‐shaped probe with a stamp‐sized metal radiofrequency emitter on one surface of the tip (25 minutes total time on average). External treatments covered the labia majora and minora, lower mons pubis, perineal body, clitoral hood, and clitoris. Full length treatment of the vagina with concentration on the anterior wall was performed. Tissue temperature during therapy was elevated to and maintained between 40°C and 45°C. No anesthesia was required. After treatment, patients immediately resumed normal activities, including sex. Results Twenty‐three of 25 patients reported an average reduction in time to orgasm of 50%. Patients also noted significant vaginal tightening effects, increased vaginal moisture, and improved vulvar and clitoral sensitivity. All anorgasmic patients reported the ability to achieve orgasms. Two patients had minimal response. Conclusion TTCRF is an effective non‐hormonal, non‐surgical option for women having difficulty achieving orgasm. Treatment also has visible tightening effects on feminine tissues and appears to increase local blood flow, resulting in increased vaginal tightness and moisture. Improved appearance and friction resulted in improved confidence and reduced performance anxiety. Lasers Surg. Med. 48:641–645, 2016. © 2016 The Authors. Lasers in Surgery and Medicine Published by Wiley Periodicals, Inc. PMID:27197701

  3. Silver halide fiber optic radiometry for temperature monitoring and control of tissues heated by microwave

    NASA Astrophysics Data System (ADS)

    Shenfeld, Ofer; Belotserkovsky, Edward; Goldwasser, Benad; Zur, Albert; Katzir, Abraham

    1993-02-01

    The heating of tissue by microwave radiation has attained a place of importance in various medical fields, such as the treatment of malignancies, urinary retention, and hypothermia. Accurate temperature measurements in these treated tissues is important for treatment planning and for the control of the heating process. It is also important to be able to measure spacial temperature distribution in the tissues because they are heated in a nonuniform way by the microwave radiation. Conventional temperature sensors used today are inaccurate in the presence of microwave radiation and require contact with the heated tissue. Fiber optic radiometry makes it possible to measure temperatures accurately in the presence of microwave radiation and does not require contact with the tissue. Accurate temperature measurements of tissues heated by microwave was obtained using a silver halide optic radiometer, enabling control of the heating process in other regions of the tissue samples. Temperature mappings of the heated tissues were performed and the nonuniform temperature distributions in these tissues was demonstrated.

  4. How the body controls brain temperature

    PubMed Central

    Zhu, Mingming; Ackerman, Joseph J. H.; Sukstanskii, Alexander L.; Yablonskiy, Dmitriy A.

    2007-01-01

    Normal brain functioning largely depends on maintaining brain temperature. However, the mechanisms protecting brain against a cooler environment are poorly understood. Reported herein is the first detailed measurement of the brain-temperature profile. It is found to be exponential, defined by a characteristic temperature shielding length, with cooler peripheral areas and a warmer brain core approaching body temperature. Direct cerebral blood flow (CBF) measurements with microspheres show that the characteristic temperature shielding length is inversely proportional to the square root of CBF in excellent agreement with a theoretical model. This “temperature shielding effect” quantifies the means by which CBF prevents “extracranial cold” from penetrating deep brain structures. The effect is crucial for research and clinical applications; the relationship between brain, body, and extracranial temperatures can now be quantitatively predicted. PMID:16840581

  5. What Controls the Arctic Lower Stratosphere Temperature?

    NASA Technical Reports Server (NTRS)

    Newman, Paul A.; Nash, Eric R.; Einaudi, Franco (Technical Monitor)

    2001-01-01

    The temperature of the Arctic lower stratosphere is critical for understanding polar ozone levels. As temperatures drop below about 195 K, polar stratospheric clouds form, which then convert HCl and ClONO2 into reactive forms that are catalysts for ozone loss reactions. Hence, the lower stratospheric temperature during the March period is a key parameter for understanding polar ozone losses. The temperature is basically understood to be a result of planetary waves which drive the polar temperature away from a cold "radiative equilibrium" state. This is demonstrated using NCEP/NCAR reanalysis calculations of the heat flux and the mean polar temperature. The temperature during the March period is fundamentally driven by the integrated impact of large scale waves moving from the troposphere to the stratosphere during the January through February period. We will further show that the recent cold years in the northern polar vortex are a result of this weakened wave driving of the stratosphere.

  6. What Controls the Arctic Lower Stratosphere Temperature?

    NASA Technical Reports Server (NTRS)

    Newman, Paul A.; Nash, Eric R.; Einaudi, Franco (Technical Monitor)

    2000-01-01

    The temperature of the Arctic lower stratosphere is critical for understanding polar ozone levels. As temperatures drop below about 195 K, polar stratospheric clouds form, which then convert HCl and ClONO2 into reactive forms that are catalysts for ozone loss reactions. Hence, the lower stratospheric temperature during the March period is a key parameter for understanding polar ozone losses. The temperature is basically understood to be a result of planetary waves which drive the polar temperature away from a cold "radiative equilibrium" state. This is demonstrated using NCEP/NCAR reanalysis calculations of the heat flux and the mean polar temperature. The temperature during the March period is fundamentally driven by the integrated impact of large scale waves moving from the troposphere to the stratosphere during the January through February period.

  7. Accurate extraction of WSe2 FETs parameters by using pulsed I-V method at various temperatures

    NASA Astrophysics Data System (ADS)

    Lee, Sung Tae; Cho, In Tak; Kang, Won Mook; Park, Byung Gook; Lee, Jong-Ho

    2016-11-01

    This work investigates the intrinsic characteristics of multilayer WSe2 field effect transistors (FETs) by analysing Pulsed I- V (PIV) and DC characteristics measured at various temperatures. In DC measurement, unwanted charge trapping due to the gate bias stress results in I- V curves different from the intrinsic characteristic. However, PIV reduces the effect of gate bias stress so that intrinsic characteristic of WSe2 FETs is obtained. The parameters such as hysteresis, field effect mobility (μeff), subthreshold slope ( SS), and threshold voltage ( V th) measured by PIV are significantly different from those obtained by DC measurement. In PIV results, the hysteresis is considerably reduced compared with DC measurement, because the charge trapping effect is significantly reduced. With increasing temperature, the field effect mobility (μeff) and subthreshold swing ( SS) are deteriorated, and threshold voltage ( V th) decreases.

  8. Vapor-modulated heat pipe for improved temperature control

    NASA Technical Reports Server (NTRS)

    Edwards, D. K.; Eninger, J. E.; Ludeke, E. E.

    1978-01-01

    Dryout induced by vapor throttling makes control of equipment temperature less dependent on variations in sink environment. Mechanism controls flow of vapor in heat pipe by using valve in return path to build difference in pressure and also difference in saturation temperature of the vapor. In steady state, valve closes just enough to produce partial dryout that achieves required temperature drop.

  9. Temperature Dependence of Factors Controlling Isoprene Emissions

    NASA Technical Reports Server (NTRS)

    Duncan, Bryan N.; Yoshida, Yasuko; Damon, Megan R.; Douglass, Anne R.; Witte, Jacquelyn C.

    2009-01-01

    We investigated the relationship of variability in the formaldehyde (HCHO) columns measured by the Aura Ozone Monitoring Instrument (OMI) to isoprene emissions in the southeastern United States for 2005-2007. The data show that the inferred, regional-average isoprene emissions varied by about 22% during summer and are well correlated with temperature, which is known to influence emissions. Part of the correlation with temperature is likely associated with other causal factors that are temperature-dependent. We show that the variations in HCHO are convolved with the temperature dependence of surface ozone, which influences isoprene emissions, and the dependence of the HCHO column to mixed layer height as OMI's sensitivity to HCHO increases with altitude. Furthermore, we show that while there is an association of drought with the variation in HCHO, drought in the southeastern U.S. is convolved with temperature.

  10. Design of a feedback-feedforward steering controller for accurate path tracking and stability at the limits of handling

    NASA Astrophysics Data System (ADS)

    Kapania, Nitin R.; Gerdes, J. Christian

    2015-12-01

    This paper presents a feedback-feedforward steering controller that simultaneously maintains vehicle stability at the limits of handling while minimising lateral path tracking deviation. The design begins by considering the performance of a baseline controller with a lookahead feedback scheme and a feedforward algorithm based on a nonlinear vehicle handling diagram. While this initial design exhibits desirable stability properties at the limits of handling, the steady-state path deviation increases significantly at highway speeds. Results from both linear and nonlinear analyses indicate that lateral path tracking deviations are minimised when vehicle sideslip is held tangent to the desired path at all times. Analytical results show that directly incorporating this sideslip tangency condition into the steering feedback dramatically improves lateral path tracking, but at the expense of poor closed-loop stability margins. However, incorporating the desired sideslip behaviour into the feedforward loop creates a robust steering controller capable of accurate path tracking and oversteer correction at the physical limits of tyre friction. Experimental data collected from an Audi TTS test vehicle driving at the handling limits on a full length race circuit demonstrates the improved performance of the final controller design.

  11. Power-controlled temperature guided retinal photocoagulation

    NASA Astrophysics Data System (ADS)

    Baade, Alexander; Schwarzer, Wadim; Koinzer, Stefan; Schlott, Kerstin; Birngruber, Reginald; Brinkmann, Ralf

    2015-03-01

    The necessary lesion strength for a given therapeutical effect in retinal photocoagulationis is currently the subject of several investigations. In some cases, even sub-visible irradiations can be beneficial for the patient. The aim of this work is to realise an automatic temperature feedback algorithm to perform uniform sub-visible and visible irradiations with a total irradiation time of 50 ms. A 75 ns/523 nm Q-switched Nd:YLF laser is used to induce optoacoustic temperature-dependent pressure amplitudes at the retina, which are detected at the cornea by an ultrasonic transducer embedded in a contact lens. A 532 nm continuous wave Nd:YAG laser serves as treatment laser and the power was adjusted during the irradiation in order to achieve the desired temperature rise. The feedback algorithm was applied for four aim temperatures, 50, 57, 65 and 82 °C. The results showed ophthalmoscopically or angiographically invisible effects for irradiations at 50 °C, despite a wide range of treatment powers. The standard deviation for the achieved temperatures ranged from 3.0 °C for an aim temperature of 50 °C to 8.8 °C for 82 °C. The introduced method could be used to improve photocoagulation for shorttime irradiations and allow the investigation of sub-visible effects.

  12. Tools for Physiology Labs: An Inexpensive Means of Temperature Control

    PubMed Central

    Krans, Jacob L.; Hoy, Ronald R.

    2005-01-01

    We describe a simple means of modulating preparation temperature, which may be useful in undergraduate physiology laboratories. The device was developed in an effort to make teaching exercises that involve temperature modulation accessible at low cost. Although we were interested in using the device specifically with the larval fruit fly preparation, it is applicable to many preparations and temperature sensitive phenomena. Feedback driven thermoregulators offer superior precision in experiments requiring temperature control, but can be prohibitively expensive, require power supplies and circuitry, and often generate large switching transients (artifacts) during physiological recording. Moreover, many interesting exercises involving temperature control can be carried out with a slightly reduced level of temperature precision. PMID:23493108

  13. Accurate calibration and control of relative humidity close to 100% by X-raying a DOPC multilayer

    DOE PAGES

    Ma, Yicong; Ghosh, Sajal K.; Bera, Sambhunath; ...

    2015-01-01

    Here in this study, we have designed a compact sample chamber that can achieve accurate and continuous control of the relative humidity (RH) in the vicinity of 100%. A 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) multilayer can be used as a humidity sensor by measuring its inter-layer repeat distance (d-spacing) via X-ray diffraction. We convert from DOPC d-spacing to RH according to a theory given in the literature and previously measured data of DOPC multilamellar vesicles in polyvinylpyrrolidone (PVP) solutions. This curve can be used for calibration of RH close to 100%, a regime where conventional sensors do not have sufficient accuracy. We demonstratemore » that this control method can provide RH accuracies of 0.1 to 0.01%, which is a factor of 10–100 improvement compared to existing methods of humidity control. Our method provides fine tuning capability of RH continuously for a single sample, whereas the PVP solution method requires new samples to be made for each PVP concentration. The use of this cell also potentially removes the need for an X-ray or neutron beam to pass through bulk water if one wishes to work close to biologically relevant conditions of nearly 100% RH.« less

  14. Accurate calibration and control of relative humidity close to 100% by X-raying a DOPC multilayer

    SciTech Connect

    Ma, Yicong; Ghosh, Sajal K.; Bera, Sambhunath; Jiang, Zhang; Tristram-Nagle, Stephanie; Lurio, Laurence B.; Sinha, Sunil K.

    2015-01-01

    Here in this study, we have designed a compact sample chamber that can achieve accurate and continuous control of the relative humidity (RH) in the vicinity of 100%. A 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) multilayer can be used as a humidity sensor by measuring its inter-layer repeat distance (d-spacing) via X-ray diffraction. We convert from DOPC d-spacing to RH according to a theory given in the literature and previously measured data of DOPC multilamellar vesicles in polyvinylpyrrolidone (PVP) solutions. This curve can be used for calibration of RH close to 100%, a regime where conventional sensors do not have sufficient accuracy. We demonstrate that this control method can provide RH accuracies of 0.1 to 0.01%, which is a factor of 10–100 improvement compared to existing methods of humidity control. Our method provides fine tuning capability of RH continuously for a single sample, whereas the PVP solution method requires new samples to be made for each PVP concentration. The use of this cell also potentially removes the need for an X-ray or neutron beam to pass through bulk water if one wishes to work close to biologically relevant conditions of nearly 100% RH.

  15. A thermosensory pathway that controls body temperature.

    PubMed

    Nakamura, Kazuhiro; Morrison, Shaun F

    2008-01-01

    Defending body temperature against environmental thermal challenges is one of the most fundamental homeostatic functions that are governed by the nervous system. Here we describe a somatosensory pathway that essentially constitutes the afferent arm of the thermoregulatory reflex that is triggered by cutaneous sensation of environmental temperature changes. Using in vivo electrophysiological and anatomical approaches in the rat, we found that lateral parabrachial neurons are pivotal in this pathway by glutamatergically transmitting cutaneous thermosensory signals received from spinal somatosensory neurons directly to the thermoregulatory command center, the preoptic area. This feedforward pathway mediates not only sympathetic and shivering thermogenic responses but also metabolic and cardiac responses to skin cooling challenges. Notably, this 'thermoregulatory afferent' pathway exists in parallel with the spinothalamocortical somatosensory pathway that mediates temperature perception. These findings make an important contribution to our understanding of both the somatosensory system and thermal homeostasis -- two mechanisms that are fundamental to the nervous system and to our survival.

  16. Temperature control system for liquid-fed ceramic melters

    SciTech Connect

    Westsik, J.H. Jr.

    1986-10-01

    A temperature-feedback system has been developed for controlling electrical power to liquid-fed ceramic melters (LFCM). Software, written for a microcomputer-based data acquisition and process monitoring system, compares glass temperatures with a temperature setpoint and adjusts the electrical power accordingly. Included in the control algorithm are steps to reject failed thermocouples, spatially average the glass temperatures, smooth the averaged temperatures over time using a digital filter, and detect foaming in the glass. The temperature control system has proved effective during all phases of melter operation including startup, steady operation, loss of feed, and shutdown. This system replaces current, power, and resistance feedback control systems used previously in controlling the LFCM process.

  17. Active structural vibration control: Robust to temperature variations

    NASA Astrophysics Data System (ADS)

    Gupta, Vivek; Sharma, Manu; Thakur, Nagesh

    2012-11-01

    d-form augmented piezoelectric constitutive equations which take into account temperature dependence of piezoelectric strain coefficient (d31) and permittivity (∈33), are converted into e-form. Using e-form constitutive equations, a finite element model of a smart two dimensional plate instrumented with piezoelectric patches is derived. Equations of motion are derived using Hamilton's variational principle. Coupled equations of motion are uncoupled using modal analysis. Modal state vectors are estimated using the Kalman observer. The first mode of smart cantilevered plate is actively controlled using negative first modal velocity feedback at various temperatures. Total control effort required to do so is calculated using the electro-mechanical impedance method. The temperature dependence of sensor voltage, control voltage, control effort and Kalman observer equations is shown analytically. Simulation results are presented using MATLAB. Variations in (i) peak sensor voltage, (ii) actual and estimated first modal velocities, (iii) peak control voltage, (iv) total control effort and (v) settling time with respect to temperature are presented. Active vibration control performance is not maintained at temperature away from reference temperature when the temperature dependence of piezoelectric stress coefficient ‘e31' and permittivity ‘∈33' is not included in piezoelectric constitutive equations. Active control of vibrations becomes robust to temperature variations when the temperature dependence of ‘e31' and ‘∈33' is included in piezoelectric constitutive equations.

  18. Water temperature controls in low arctic rivers

    NASA Astrophysics Data System (ADS)

    King, Tyler V.; Neilson, Bethany T.; Overbeck, Levi D.; Kane, Douglas L.

    2016-06-01

    Understanding the dynamics of heat transfer mechanisms is critical for forecasting the effects of climate change on arctic river temperatures. Climate influences on arctic river temperatures can be particularly important due to corresponding effects on nutrient dynamics and ecological responses. It was hypothesized that the same heat and mass fluxes affect arctic and temperate rivers, but that relative importance and variability over time and space differ. Through data collection and application of a river temperature model that accounts for the primary heat fluxes relevant in temperate climates, heat fluxes were estimated for a large arctic basin over wide ranges of hydrologic conditions. Heat flux influences similar to temperate systems included dominant shortwave radiation, shifts from positive to negative sensible heat flux with distance downstream, and greater influences of lateral inflows in the headwater region. Heat fluxes that differed from many temperate systems included consistently negative net longwave radiation and small average latent heat fluxes. Radiative heat fluxes comprised 88% of total absolute heat flux while all other heat fluxes contributed less than 5% on average. Periodic significance was seen for lateral inflows (up to 26%) and latent heat flux (up to 18%) in the lower and higher stream order portions of the watershed, respectively. Evenly distributed lateral inflows from large scale flow differencing and temperatures from representative tributaries provided a data efficient method for estimating the associated heat loads. Poor model performance under low flows demonstrated need for further testing and data collection to support the inclusion of additional heat fluxes.

  19. Pressure-Sensitive System for Gas-Temperature Control

    NASA Technical Reports Server (NTRS)

    Cesaro, Richard S; Matz, Norman

    1948-01-01

    A thermodynamic relation is derived and simplified for use as a temperature-limiting control equation involving measurement of gas temperature before combustion and gas pressures before and after combustion. For critical flow in the turbine nozzles of gas-turbine engines, the control equation is further simplified to require only measurements upstream of the burner. Hypothetical control systems are discussed to illustrate application of the control equations.

  20. Accurate measurements and temperature dependence of the water vapor self-continuum absorption in the 2.1 μm atmospheric window.

    PubMed

    Ventrillard, I; Romanini, D; Mondelain, D; Campargue, A

    2015-10-07

    In spite of its importance for the evaluation of the Earth radiative budget, thus for climate change, very few measurements of the water vapor continuum are available in the near infrared atmospheric windows especially at temperature conditions relevant for our atmosphere. In addition, as a result of the difficulty to measure weak broadband absorption signals, the few available measurements show large disagreements. We report here accurate measurements of the water vapor self-continuum absorption in the 2.1 μm window by Optical Feedback Cavity Enhanced Absorption Spectroscopy (OF-CEAS) for two spectral points located at the low energy edge and at the center of the 2.1 μm transparency window, at 4302 and 4723 cm(-1), respectively. Self-continuum cross sections, CS, were retrieved with a few % relative uncertainty, from the quadratic dependence of the spectrum base line level measured as a function of water vapor pressure, between 0 and 16 Torr. At 296 K, the CS value at 4302 cm(-1) is found 40% higher than predicted by the MT_CKD V2.5 model, while at 4723 cm(-1), our value is 5 times larger than the MT_CKD value. On the other hand, these OF-CEAS CS values are significantly smaller than recent measurements by Fourier transform spectroscopy at room temperature. The temperature dependence of the self-continuum cross sections was also investigated for temperatures between 296 K and 323 K (23-50 °C). The derived temperature variation is found to be similar to that derived from previous Fourier transform spectrometer (FTS) measurements performed at higher temperatures, between 350 K and 472 K. The whole set of measurements spanning the 296-472 K temperature range follows a simple exponential law in 1/T with a slope close to the dissociation energy of the water dimer, D0 ≈ 1100 cm(-1).

  1. New experimental methodology, setup and LabView program for accurate absolute thermoelectric power and electrical resistivity measurements between 25 and 1600 K: Application to pure copper, platinum, tungsten, and nickel at very high temperatures

    NASA Astrophysics Data System (ADS)

    Abadlia, L.; Gasser, F.; Khalouk, K.; Mayoufi, M.; Gasser, J. G.

    2014-09-01

    In this paper we describe an experimental setup designed to measure simultaneously and very accurately the resistivity and the absolute thermoelectric power, also called absolute thermopower or absolute Seebeck coefficient, of solid and liquid conductors/semiconductors over a wide range of temperatures (room temperature to 1600 K in present work). A careful analysis of the existing experimental data allowed us to extend the absolute thermoelectric power scale of platinum to the range 0-1800 K with two new polynomial expressions. The experimental device is controlled by a LabView program. A detailed description of the accurate dynamic measurement methodology is given in this paper. We measure the absolute thermoelectric power and the electrical resistivity and deduce with a good accuracy the thermal conductivity using the relations between the three electronic transport coefficients, going beyond the classical Wiedemann-Franz law. We use this experimental setup and methodology to give new very accurate results for pure copper, platinum, and nickel especially at very high temperatures. But resistivity and absolute thermopower measurement can be more than an objective in itself. Resistivity characterizes the bulk of a material while absolute thermoelectric power characterizes the material at the point where the electrical contact is established with a couple of metallic elements (forming a thermocouple). In a forthcoming paper we will show that the measurement of resistivity and absolute thermoelectric power characterizes advantageously the (change of) phase, probably as well as DSC (if not better), since the change of phases can be easily followed during several hours/days at constant temperature.

  2. New experimental methodology, setup and LabView program for accurate absolute thermoelectric power and electrical resistivity measurements between 25 and 1600 K: application to pure copper, platinum, tungsten, and nickel at very high temperatures.

    PubMed

    Abadlia, L; Gasser, F; Khalouk, K; Mayoufi, M; Gasser, J G

    2014-09-01

    In this paper we describe an experimental setup designed to measure simultaneously and very accurately the resistivity and the absolute thermoelectric power, also called absolute thermopower or absolute Seebeck coefficient, of solid and liquid conductors/semiconductors over a wide range of temperatures (room temperature to 1600 K in present work). A careful analysis of the existing experimental data allowed us to extend the absolute thermoelectric power scale of platinum to the range 0-1800 K with two new polynomial expressions. The experimental device is controlled by a LabView program. A detailed description of the accurate dynamic measurement methodology is given in this paper. We measure the absolute thermoelectric power and the electrical resistivity and deduce with a good accuracy the thermal conductivity using the relations between the three electronic transport coefficients, going beyond the classical Wiedemann-Franz law. We use this experimental setup and methodology to give new very accurate results for pure copper, platinum, and nickel especially at very high temperatures. But resistivity and absolute thermopower measurement can be more than an objective in itself. Resistivity characterizes the bulk of a material while absolute thermoelectric power characterizes the material at the point where the electrical contact is established with a couple of metallic elements (forming a thermocouple). In a forthcoming paper we will show that the measurement of resistivity and absolute thermoelectric power characterizes advantageously the (change of) phase, probably as well as DSC (if not better), since the change of phases can be easily followed during several hours/days at constant temperature.

  3. New experimental methodology, setup and LabView program for accurate absolute thermoelectric power and electrical resistivity measurements between 25 and 1600 K: Application to pure copper, platinum, tungsten, and nickel at very high temperatures

    SciTech Connect

    Abadlia, L.; Mayoufi, M.; Gasser, F.; Khalouk, K.; Gasser, J. G.

    2014-09-15

    In this paper we describe an experimental setup designed to measure simultaneously and very accurately the resistivity and the absolute thermoelectric power, also called absolute thermopower or absolute Seebeck coefficient, of solid and liquid conductors/semiconductors over a wide range of temperatures (room temperature to 1600 K in present work). A careful analysis of the existing experimental data allowed us to extend the absolute thermoelectric power scale of platinum to the range 0-1800 K with two new polynomial expressions. The experimental device is controlled by a LabView program. A detailed description of the accurate dynamic measurement methodology is given in this paper. We measure the absolute thermoelectric power and the electrical resistivity and deduce with a good accuracy the thermal conductivity using the relations between the three electronic transport coefficients, going beyond the classical Wiedemann-Franz law. We use this experimental setup and methodology to give new very accurate results for pure copper, platinum, and nickel especially at very high temperatures. But resistivity and absolute thermopower measurement can be more than an objective in itself. Resistivity characterizes the bulk of a material while absolute thermoelectric power characterizes the material at the point where the electrical contact is established with a couple of metallic elements (forming a thermocouple). In a forthcoming paper we will show that the measurement of resistivity and absolute thermoelectric power characterizes advantageously the (change of) phase, probably as well as DSC (if not better), since the change of phases can be easily followed during several hours/days at constant temperature.

  4. Design of a computerized, temperature-controlled, recirculating aquaria system

    USGS Publications Warehouse

    Widmer, A.M.; Carveth, C.J.; Keffler, J.W.; Bonar, Scott A.

    2006-01-01

    We built a recirculating aquaria system with computerized temperature control to maintain static temperatures, increase temperatures 1 ??C/day, and maintain diel temperature fluctuations up to 10 ??C. A LabVIEW program compared the temperature recorded by thermocouples in fish tanks to a desired set temperature and then calculated the amount of hot or cold water to add to tanks to reach or maintain the desired temperature. Intellifaucet?? three-way mixing valves controlled temperature of the input water and ensured that all fish tanks had the same turnover rate. The system was analyzed over a period of 50 days and was fully functional for 96% of that time. Six different temperature treatments were run simultaneously in 18, 72 L fish tanks and temperatures stayed within 0.5 ??C of set temperature. We used the system to determine the upper temperature tolerance of fishes, but it could be used in aquaculture, ecological studies, or other aquatic work where temperature control is required. ?? 2005 Elsevier B.V. All rights reserved.

  5. Accurate control of oxygen level in cells during culture on silicone rubber membranes with application to stem cell differentiation.

    PubMed

    Powers, Daryl E; Millman, Jeffrey R; Bonner-Weir, Susan; Rappel, Michael J; Colton, Clark K

    2010-01-01

    Oxygen level in mammalian cell culture is often controlled by placing culture vessels in humidified incubators with a defined gas phase partial pressure of oxygen (pO(2gas)). Because the cells are consuming oxygen supplied by diffusion, a difference between pO(2gas) and that experienced by the cells (pO(2cell)) arises, which is maximal when cells are cultured in vessels with little or no oxygen permeability. Here, we demonstrate theoretically that highly oxygen-permeable silicone rubber membranes can be used to control pO(2cell) during culture of cells in monolayers and aggregates much more accurately and can achieve more rapid transient response following a disturbance than on polystyrene and fluorinated ethylene-propylene copolymer membranes. Cell attachment on silicone rubber was achieved by physical adsorption of fibronectin or Matrigel. We use these membranes for the differentiation of mouse embryonic stem cells to cardiomyocytes and compare the results with culture on polystyrene or on silicone rubber on top of polystyrene. The fraction of cells that are cardiomyocyte-like increases with decreasing pO(2) only when using oxygen-permeable silicone membrane-based dishs, which contract on silicone rubber but not polystyrene. The high permeability of silicone rubber results in pO(2cell) being equal to pO(2gas) at the tissue-membrane interface. This, together with geometric information from histological sections, facilitates development of a model from which the pO(2) distribution within the resulting aggregates is computed. Silicone rubber membranes have significant advantages over polystyrene in controlling pO(2cell), and these results suggest they are a valuable tool for investigating pO(2) effects in many applications, such as stem cell differentiation.

  6. 14 CFR 25.1157 - Carburetor air temperature controls.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

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

  7. 14 CFR 29.1157 - Carburetor air temperature controls.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

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

  8. 14 CFR 29.1157 - Carburetor air temperature controls.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

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

  9. 14 CFR 25.1157 - Carburetor air temperature controls.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

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

  10. 14 CFR 25.1157 - Carburetor air temperature controls.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Carburetor air temperature controls. 25.1157 Section 25.1157 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF... Accessories § 25.1157 Carburetor air temperature controls. There must be a separate carburetor air...

  11. 14 CFR 25.1157 - Carburetor air temperature controls.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Carburetor air temperature controls. 25.1157 Section 25.1157 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF... Accessories § 25.1157 Carburetor air temperature controls. There must be a separate carburetor air...

  12. 14 CFR 29.1157 - Carburetor air temperature controls.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Carburetor air temperature controls. 29.1157 Section 29.1157 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF... Accessories § 29.1157 Carburetor air temperature controls. There must be a separate carburetor air...

  13. 14 CFR 29.1157 - Carburetor air temperature controls.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

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

  14. 14 CFR 29.1157 - Carburetor air temperature controls.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

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

  15. 14 CFR 25.1157 - Carburetor air temperature controls.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

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

  16. Effects of Temperature and Controlled Atmospheres on Codling Moth Metabolism

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Although controlled atmosphere temperature treatments are effective in controlling codling moth in fruit, the mechanism by which this combination treatment kills the larvae is unknown. Differential scanning calorimetry was used to determine the effects of elevated temperatures, low oxygen, and high ...

  17. Microprocessor Based Temperature Control of Liquid Delivery with Flow Disturbances.

    ERIC Educational Resources Information Center

    Kaya, Azmi

    1982-01-01

    Discusses analytical design and experimental verification of a PID control value for a temperature controlled liquid delivery system, demonstrating that the analytical design techniques can be experimentally verified by using digital controls as a tool. Digital control instrumentation and implementation are also demonstrated and documented for…

  18. Embedded resistance wire as a heating element for temperature control in microbioreactors

    NASA Astrophysics Data System (ADS)

    Nazrul Hisham Zainal Alam, Muhd; Schäpper, Daniel; Gernaey, Krist V.

    2010-05-01

    This paper presents the technical realization of a low-cost heating element consisting of a resistance wire in a microbioreactor, as well as the implementation and performance assessment of an on/off controller for temperature control of the microbioreactor content based on this heating element. The microbioreactor (working volume of 100 µL) is designed to work bubble-free, and is fabricated out of the polymers poly(methylmethacrylate) (PMMA) and poly(dimethylsiloxane) (PDMS). The temperature is measured with a Pt 100 sensor, and the resistance wires are embedded in the polymer such that they either surround the reactor chamber or are placed underneath it. The latter can achieve an even temperature distribution across the reactor chamber and direct heating of the reactor content. We show that an integrated resistance wire coupled to a simple on/off controller results in accurate temperature control of the reactor (±0.1 °C of the set point value) and provides a good disturbance rejection capability (corrective action for a sudden temperature drop of 2.5 °C at an operating temperature of 50 °C takes less than 30 s). Finally, we also demonstrate the workability of the established temperature control in a batch Saccharomyces cerevisiae cultivation in a microbioreactor.

  19. Definition study for temperature control in advanced protein crystal growth

    NASA Astrophysics Data System (ADS)

    Nyce, Thomas A.; Rosenberger, Franz; Sowers, Jennifer W.; Monaco, Lisa A.

    1990-09-01

    Some of the technical requirements for an expedient application of temperature control to advanced protein crystal growth activities are defined. Lysozome was used to study the effects of temperature ramping and temperature gradients for nucleation/dissolution and consecutive growth of sizable crystals and, to determine a prototype temperature program. The solubility study was conducted using equine serum albumin (ESA) which is an extremely stable, clinically important protein due to its capability to bind and transport many different small ions and molecules.

  20. Definition study for temperature control in advanced protein crystal growth

    NASA Technical Reports Server (NTRS)

    Nyce, Thomas A.; Rosenberger, Franz; Sowers, Jennifer W.; Monaco, Lisa A.

    1990-01-01

    Some of the technical requirements for an expedient application of temperature control to advanced protein crystal growth activities are defined. Lysozome was used to study the effects of temperature ramping and temperature gradients for nucleation/dissolution and consecutive growth of sizable crystals and, to determine a prototype temperature program. The solubility study was conducted using equine serum albumin (ESA) which is an extremely stable, clinically important protein due to its capability to bind and transport many different small ions and molecules.

  1. Toward accurate thermochemistry of the (24)MgH, (25)MgH, and (26)MgH molecules at elevated temperatures: corrections due to unbound states.

    PubMed

    Szidarovszky, Tamás; Császár, Attila G

    2015-01-07

    The total partition functions QT and their first two moments Q(')T and Q(″)T, together with the isobaric heat capacities CpT, are computed a priori for three major MgH isotopologues on the temperature range of T = 100-3000 K using the recent highly accurate potential energy curve, spin-rotation, and non-adiabatic correction functions of Henderson et al. [J. Phys. Chem. A 117, 13373 (2013)]. Nuclear motion computations are carried out on the ground electronic state to determine the (ro)vibrational energy levels and the scattering phase shifts. The effect of resonance states is found to be significant above about 1000 K and it increases with temperature. Even very short-lived states, due to their relatively large number, have significant contributions to QT at elevated temperatures. The contribution of scattering states is around one fourth of that of resonance states but opposite in sign. Uncertainty estimates are given for the possible error sources, suggesting that all computed thermochemical properties have an accuracy better than 0.005% up to 1200 K. Between 1200 and 2500 K, the uncertainties can rise to around 0.1%, while between 2500 K and 3000 K, a further increase to 0.5% might be observed for Q(″)T and CpT, principally due to the neglect of excited electronic states. The accurate thermochemical data determined are presented in the supplementary material for the three isotopologues of (24)MgH, (25)MgH, and (26)MgH at 1 K increments. These data, which differ significantly from older standard data, should prove useful for astronomical models incorporating thermodynamic properties of these species.

  2. All-solid very large mode area ytterbium-doped silica microstructured fiber based on accurate control on cladding index.

    PubMed

    Wei, Huifeng; Chen, Kangkang; Yang, Yucheng; Li, Jinyan

    2016-04-18

    We have demonstrated a new approach for developing very large mode area silica-based microstructured Ytterbium (Yb)-doped fibers. The microstructured region acting as pump cladding around the core is composed by periodically arranged low-index Fluorine-doped silica inclusions with an extremely low filling ratio of 0.088. To the best of our knowledge, we achieved the most accurate controlling on cladding index by 1 × 10-5 via our passively doped cladding (PDC) method. Two fibers with 127μm and 50μm core diameter respectively were fabricated from the same final preform designed by this approach. It is verified that our 50μm core diameter fiber can maintain robust single mode behavior at 1064nm wavelength. The advantage of an all-solid structure along with a much simpler fabrication process makes our approach very suitable for realizing very large mode area fibers for high power fiber laser application.

  3. Automatic and accurate reconstruction of distal humerus contours through B-Spline fitting based on control polygon deformation.

    PubMed

    Mostafavi, Kamal; Tutunea-Fatan, O Remus; Bordatchev, Evgueni V; Johnson, James A

    2014-12-01

    The strong advent of computer-assisted technologies experienced by the modern orthopedic surgery prompts for the expansion of computationally efficient techniques to be built on the broad base of computer-aided engineering tools that are readily available. However, one of the common challenges faced during the current developmental phase continues to remain the lack of reliable frameworks to allow a fast and precise conversion of the anatomical information acquired through computer tomography to a format that is acceptable to computer-aided engineering software. To address this, this study proposes an integrated and automatic framework capable to extract and then postprocess the original imaging data to a common planar and closed B-Spline representation. The core of the developed platform relies on the approximation of the discrete computer tomography data by means of an original two-step B-Spline fitting technique based on successive deformations of the control polygon. In addition to its rapidity and robustness, the developed fitting technique was validated to produce accurate representations that do not deviate by more than 0.2 mm with respect to alternate representations of the bone geometry that were obtained through different-contact-based-data acquisition or data processing methods.

  4. Thermoelectric temperature control system for the pushbroom microwave radiometer (PBMR)

    NASA Astrophysics Data System (ADS)

    Dillon-Townes, L. A.; Averill, R. D.

    1984-06-01

    A closed loop thermoelectric temperature control system is developed for stabilizing sensitive RF integrated circuits within a microwave radiometer to an accuracy of + or - 0.1 C over a range of ambient conditions from -20 C to +45 C. The dual mode (heating and cooling) control concept utilizes partial thermal isolation of the RF units from an instrument deck which is thermally controlled by thermoelectric coolers and thin film heaters. The temperature control concept is simulated with a thermal analyzer program (MITAS) which consists of 37 nodes and 61 conductors. A full scale thermal mockup is tested in the laboratory at temperatures of 0 C, 21 C, and 45 C to confirm the validity of the control concept. A flight radiometer and temperature control system is successfully flight tested on the NASA Skyvan aircraft.

  5. Thermoelectric temperature control system for the pushbroom microwave radiometer (PBMR)

    NASA Technical Reports Server (NTRS)

    Dillon-Townes, L. A.; Averill, R. D.

    1984-01-01

    A closed loop thermoelectric temperature control system is developed for stabilizing sensitive RF integrated circuits within a microwave radiometer to an accuracy of + or - 0.1 C over a range of ambient conditions from -20 C to +45 C. The dual mode (heating and cooling) control concept utilizes partial thermal isolation of the RF units from an instrument deck which is thermally controlled by thermoelectric coolers and thin film heaters. The temperature control concept is simulated with a thermal analyzer program (MITAS) which consists of 37 nodes and 61 conductors. A full scale thermal mockup is tested in the laboratory at temperatures of 0 C, 21 C, and 45 C to confirm the validity of the control concept. A flight radiometer and temperature control system is successfully flight tested on the NASA Skyvan aircraft.

  6. System for controlling the operating temperature of a fuel cell

    DOEpatents

    Fabis, Thomas R.; Makiel, Joseph M.; Veyo, Stephen E.

    2006-06-06

    A method and system are provided for improved control of the operating temperature of a fuel cell (32) utilizing an improved temperature control system (30) that varies the flow rate of inlet air entering the fuel cell (32) in response to changes in the operating temperature of the fuel cell (32). Consistent with the invention an improved temperature control system (30) is provided that includes a controller (37) that receives an indication of the temperature of the inlet air from a temperature sensor (39) and varies the heat output by at least one heat source (34, 36) to maintain the temperature of the inlet air at a set-point T.sub.inset. The controller (37) also receives an indication of the operating temperature of the fuel cell (32) and varies the flow output by an adjustable air mover (33), within a predetermined range around a set-point F.sub.set, in order to maintain the operating temperature of the fuel cell (32) at a set-point T.sub.opset.

  7. Infrared sensor-based temperature control for domestic induction cooktops.

    PubMed

    Lasobras, Javier; Alonso, Rafael; Carretero, Claudio; Carretero, Enrique; Imaz, Eduardo

    2014-03-14

    In this paper, a precise real-time temperature control system based on infrared (IR) thermometry for domestic induction cooking is presented. The temperature in the vessel constitutes the control variable of the closed-loop power control system implemented in a commercial induction cooker. A proportional-integral controller is applied to establish the output power level in order to reach the target temperature. An optical system and a signal conditioning circuit have been implemented. For the signal processing a microprocessor with 12-bit ADC and a sampling rate of 1 Ksps has been used. The analysis of the contributions to the infrared radiation permits the definition of a procedure to estimate the temperature of the vessel with a maximum temperature error of 5 °C in the range between 60 and 250 °C for a known cookware emissivity. A simple and necessary calibration procedure with a black-body sample is presented.

  8. Temperature Control of Avalanche Photodiode Using Thermoelectric Cooler

    NASA Technical Reports Server (NTRS)

    Refaat, Tamer F.; Luck, William S., Jr.; DeYoung, Russell J.

    1999-01-01

    Avalanche photodiodes (APDS) are quantum optical detectors that are used for visible and near infrared optical detection applications. Although APDs are compact, rugged, and have an internal gain mechanism that is suitable for low light intensity; their responsivity, and therefore their output, is strongly dependent on the device temperature. Thermoelectric coolers (TEC) offers a suitable solution to this problem. A TEC is a solid state cooling device, which can be controlled by changing its current. TECs are compact and rugged, and they can precisely control the temperature to within 0.1 C with more than a 150 C temperature gradient between its surfaces. In this Memorandum, a proportional integral (PI) temperature controller for APDs using a TEC is discussed. The controller is compact and can successfully cool the APD to almost 0 C in an ambient temperature environment of up to 27 C.

  9. Infrared Sensor-Based Temperature Control for Domestic Induction Cooktops

    PubMed Central

    Lasobras, Javier; Alonso, Rafael; Carretero, Claudio; Carretero, Enrique; Imaz, Eduardo

    2014-01-01

    In this paper, a precise real-time temperature control system based on infrared (IR) thermometry for domestic induction cooking is presented. The temperature in the vessel constitutes the control variable of the closed-loop power control system implemented in a commercial induction cooker. A proportional-integral controller is applied to establish the output power level in order to reach the target temperature. An optical system and a signal conditioning circuit have been implemented. For the signal processing a microprocessor with 12-bit ADC and a sampling rate of 1 Ksps has been used. The analysis of the contributions to the infrared radiation permits the definition of a procedure to estimate the temperature of the vessel with a maximum temperature error of 5 °C in the range between 60 and 250 °C for a known cookware emissivity. A simple and necessary calibration procedure with a black-body sample is presented. PMID:24638125

  10. Seasonal mean temperature changes control future heat waves

    NASA Astrophysics Data System (ADS)

    Argüeso, Daniel; Di Luca, Alejandro; Perkins-Kirkpatrick, Sarah E.; Evans, Jason P.

    2016-07-01

    Increased temperature will result in longer, more frequent, and more intense heat waves. Changes in temperature variability have been deemed necessary to account for future heat wave characteristics. However, this has been quantified only in Europe and North America, while the rest of the globe remains unexplored. Using late century global climate projections, we show that annual mean temperature increases is the key factor defining heat wave changes in most regions. We find that commonly studied areas are an exception rather than the standard and the mean climate change signal generally outweighs any influence from variability changes. More importantly, differences in warming across seasons are responsible for most of the heat wave changes and their consideration relegates the contribution of variability to a marginal role. This reveals that accurately capturing mean seasonal changes is crucial to estimate future heat waves and reframes our interpretation of future temperature extremes.

  11. Ultraviolet Rayleigh-Mie lidar by use of a multicavity Fabry-Perot filter for accurate temperature profiling of the troposphere.

    PubMed

    Hua, Dengxin; Kobayashi, Takao

    2005-10-20

    A UV Rayleigh-Mie scattering lidar system at 355 nm has been upgraded for more-accurate temperature profiling of the troposphere by use of a new multicavity Fabry-Perot etalon (MCFPE) filter. The MCFPE filter, which was designed to improve the stability and operational characteristics of the lidar system, has three filter bandpass functions and separates one Mie scattering and two Rayleigh scattering signals from the lidar return signal and simultaneously acts as a laser frequency discriminator to lock the laser frequency. Moreover, a high-resolution grating is employed to block signal interference from Raman scattering and the solar background. A practical lidar system, which features strong system stabilization and high measurement accuracy, has been built, and the performance of the lidar system has been verified by comparison of temperature profiling between the lidar and a radiosonde. Good agreement between the two instrument measurements was obtained in terms of lapse rate and inversion layer height. Statistical temperature errors of less than 1 K up to a height of 3 km are obtainable with 5 min observation time for daytime measurements.

  12. Temperature and melt solid interface control during crystal growth

    NASA Technical Reports Server (NTRS)

    Batur, Celal

    1990-01-01

    Findings on the adaptive control of a transparent Bridgman crystal growth furnace are summarized. The task of the process controller is to establish a user specified axial temperature profile by controlling the temperatures in eight heating zones. The furnace controller is built around a computer. Adaptive PID (Proportional Integral Derivative) and Pole Placement control algorithms are applied. The need for adaptive controller stems from the fact that the zone dynamics changes with respect to time. The controller was tested extensively on the Lead Bromide crystal growth. Several different temperature profiles and ampoule's translational rates are tried. The feasibility of solid liquid interface quantification by image processing was determined. The interface is observed by a color video camera and the image data file is processed to determine if the interface is flat, convex or concave.

  13. Implementation of Temperature Sequential Controller on Variable Speed Drive

    NASA Astrophysics Data System (ADS)

    Cheong, Z. X.; Barsoum, N. N.

    2008-10-01

    There are many pump and motor installations with quite extensive speed variation, such as Sago conveyor, heating, ventilation and air conditioning (HVAC) and water pumping system. A common solution for these applications is to run several fixed speed motors in parallel, with flow control accomplish by turning the motors on and off. This type of control method causes high in-rush current, and adds a risk of damage caused by pressure transients. This paper explains the design and implementation of a temperature speed control system for use in industrial and commercial sectors. Advanced temperature speed control can be achieved by using ABB ACS800 variable speed drive-direct torque sequential control macro, programmable logic controller and temperature transmitter. The principle of direct torque sequential control macro (DTC-SC) is based on the control of torque and flux utilizing the stator flux field orientation over seven preset constant speed. As a result of continuous comparison of ambient temperature to the references temperatures; electromagnetic torque response is particularly fast to the motor state and it is able maintain constant speeds. Experimental tests have been carried out by using ABB ACS800-U1-0003-2, to validate the effectiveness and dynamic respond of ABB ACS800 against temperature variation, loads, and mechanical shocks.

  14. Battery pack/controller for high temperature applications

    SciTech Connect

    Wolfenbarger, F.M.

    1986-01-01

    At temperatures in excess of 300/sup 0/C, standard conductive wirelines cannot be used for signal or power transmission in geothermal wells. At such temperatures, a mechanical slickline can be used to raise and lower instrumentation, but the instrumentation control and power must then be self contained. This paper reviews the development of a battery and timing circuit to control a motor in a Los Alamos National Laboratory sampling tool. The battery pack-controller circuitry enclosed in a dewar was used in the Salton Sea Scientific Drilling Project (SSSDP) for temperatures approaching 400/sup 0/C.

  15. Accurate Monte Carlo simulations on FCC and HCP Lennard-Jones solids at very low temperatures and high reduced densities up to 1.30.

    PubMed

    Adidharma, Hertanto; Tan, Sugata P

    2016-07-07

    Canonical Monte Carlo simulations on face-centered cubic (FCC) and hexagonal closed packed (HCP) Lennard-Jones (LJ) solids are conducted at very low temperatures (0.10 ≤ T(∗) ≤ 1.20) and high densities (0.96 ≤ ρ(∗) ≤ 1.30). A simple and robust method is introduced to determine whether or not the cutoff distance used in the simulation is large enough to provide accurate thermodynamic properties, which enables us to distinguish the properties of FCC from that of HCP LJ solids with confidence, despite their close similarities. Free-energy expressions derived from the simulation results are also proposed, not only to describe the properties of those individual structures but also the FCC-liquid, FCC-vapor, and FCC-HCP solid phase equilibria.

  16. Accurate Monte Carlo simulations on FCC and HCP Lennard-Jones solids at very low temperatures and high reduced densities up to 1.30

    NASA Astrophysics Data System (ADS)

    Adidharma, Hertanto; Tan, Sugata P.

    2016-07-01

    Canonical Monte Carlo simulations on face-centered cubic (FCC) and hexagonal closed packed (HCP) Lennard-Jones (LJ) solids are conducted at very low temperatures (0.10 ≤ T∗ ≤ 1.20) and high densities (0.96 ≤ ρ∗ ≤ 1.30). A simple and robust method is introduced to determine whether or not the cutoff distance used in the simulation is large enough to provide accurate thermodynamic properties, which enables us to distinguish the properties of FCC from that of HCP LJ solids with confidence, despite their close similarities. Free-energy expressions derived from the simulation results are also proposed, not only to describe the properties of those individual structures but also the FCC-liquid, FCC-vapor, and FCC-HCP solid phase equilibria.

  17. Control of temperature for health and productivity inoffices

    SciTech Connect

    Seppanen, Olli; Fisk, William J.; Faulkner, David

    2004-06-01

    Indoor temperature is one of the fundamental characteristics of the indoor environment. It can be controlled with different accuracy depending on the building and its HVAC system. The purpose of this study was to evaluate the potential benefits of improved temperature control, and apply the information for a cost-benefit analyses. The indoor temperature affects several human responses, including thermal comfort, perceived air quality, sick building syndrome symptoms and performance in work. In this study we focused on the effects of temperature on performance in work. We collected and analyzed the literature relating the performance in work and temperature. The results of multiple studies are relatively consistent and show an average relationship of 2% decrement in work performance per degree C when the temperature is above 25 C. Less data were available on the performance in low temperatures. However, studies show a strong effect on manual tasks with temperatures below thermal neutrality as soon as the temperature of hands decreased due to control of blood flow. When the estimated productivity decrement from elevated temperatures was applied to data from a study of night-time ventilative cooling, the estimated value of productivity improvements were 32 to 120 times greater than the cost of energy to run fans during the night.

  18. Research on adaptive temperature control in sound field induced by self-focused concave spherical transducer.

    PubMed

    Hu, Jiwen; Qian, Shengyou; Ding, Yajun

    2010-05-01

    Temperature control of hyperthermia treatments is generally implemented with multipoint feedback system comprised of phased-array transducer, which is complicated and high cost. Our simulations to the acoustic field induced by a self-focused concave spherical transducer (0.5MHz, 9cm aperture width, 8.0cm focal length) show that the distribution of temperature can keep the same "cigar shape" in the focal region during ultrasound insonation. Based on the characteristic of the temperature change, a two-dimensional model of a "cigar shape" tumor is designed and tested through numerical simulation. One single-point on the border of the "cigar shape" tumor is selected as the control target and is controlled at the temperature of 43 degrees C by using a self-tuning regulator (STR). Considering the nonlinear effects of biological medium, an accurate state-space model obtained via the finite Fourier integral transformation to the bioheat equation is presented and used for calculating temperature. Computer simulations were performed with the perfusion rates of 2.0kg/(m(3)s) and 4.5kg/(m(3)s) to the different targets, it was found that the temperatures on the border of the "cigar shape" tumor can achieve the desired temperature of 43 degrees C by control of one single-point. A larger perfusion rate requires a higher power output to obtain the same temperature elevation under the same insonation time and needs a higher cost for compensating the energy loss carried away by blood flow after steady state. The power output increases with the controlled region while achieving the same temperature at the same time. Especially, there is no overshoot during temperature elevation and no oscillation after steady state. The simulation results demonstrate that the proposed approach may offers a way for obtaining a single-point, low-cost hyperthermia system.

  19. Accurate measurements and temperature dependence of the water vapor self-continuum absorption in the 2.1 μm atmospheric window

    SciTech Connect

    Ventrillard, I.; Romanini, D.; Mondelain, D.; Campargue, A.

    2015-10-07

    In spite of its importance for the evaluation of the Earth radiative budget, thus for climate change, very few measurements of the water vapor continuum are available in the near infrared atmospheric windows especially at temperature conditions relevant for our atmosphere. In addition, as a result of the difficulty to measure weak broadband absorption signals, the few available measurements show large disagreements. We report here accurate measurements of the water vapor self-continuum absorption in the 2.1 μm window by Optical Feedback Cavity Enhanced Absorption Spectroscopy (OF-CEAS) for two spectral points located at the low energy edge and at the center of the 2.1 μm transparency window, at 4302 and 4723 cm{sup −1}, respectively. Self-continuum cross sections, C{sub S}, were retrieved with a few % relative uncertainty, from the quadratic dependence of the spectrum base line level measured as a function of water vapor pressure, between 0 and 16 Torr. At 296 K, the C{sub S} value at 4302 cm{sup −1} is found 40% higher than predicted by the MT-CKD V2.5 model, while at 4723 cm{sup −1}, our value is 5 times larger than the MT-CKD value. On the other hand, these OF-CEAS C{sub S} values are significantly smaller than recent measurements by Fourier transform spectroscopy at room temperature. The temperature dependence of the self-continuum cross sections was also investigated for temperatures between 296 K and 323 K (23-50 °C). The derived temperature variation is found to be similar to that derived from previous Fourier transform spectrometer (FTS) measurements performed at higher temperatures, between 350 K and 472 K. The whole set of measurements spanning the 296-472 K temperature range follows a simple exponential law in 1/T with a slope close to the dissociation energy of the water dimer, D{sub 0} ≈ 1100 cm{sup −1}.

  20. Possibilities of improving the parameters of hyperthermia in regional isolated limb perfusion using epidural bupivacaine and accurate temperature measurement of the three layers of limb tissue.

    PubMed

    Jastrzebski, Tomasz; Sommer, Anna; Swierblewski, Maciej; Lass, Piotr; Rogowski, Jan; Drucis, Kamil; Kopacz, Andrzej

    2006-06-01

    The present study presents the author's modification of the method, which aims to create proper parameters of the treatment. The selected group consisted of 15 women and eight men, with a mean age of 57.2 years (range from 26 to 72 years). The patients were divided into two groups, depending on whether they were given epidural bupivacaine (group I - 13 patients treated between the years 2001 and 2004) or not [group II (control) - 10 patients treated earlier, between the years 1997 and 2000]. We observed a significant change in the temperature of thigh muscles (P=0.009) and shank muscles (P=0.006). In the control group II, there was a statistically significant difference (P=0.048) in the temperatures between the muscles and subcutaneous tissue on the one hand and the shank skin on the other. That difference was mean 0.67 degrees Celsius (from 0.4 to 0.9) during the perfusion after applying the cytostatic. The temperature of the skin was lower than the temperature of the deeper tissues of the shank and did not exceed 39.9 degrees Celsius. Such a difference in the temperatures was not observed in case of the group I patients who were given bupivacaine into the extrameningeal space before applying the cytostatic. The difference in the temperatures was on average 0.26 degrees Celsius and was not statistically significant (P=0.99), whereas the shank skin temperature was 40.0-40.6 degrees Celsius. The attained results imply that despite the noticeable improvement in the heating of the limb muscles after application of bupivacaine, the improvement in the heating of the skin and subcutaneous tissue is still not satisfactory, although the growing tendency implies such a possibility.

  1. Synchronous temperature rate control for refrigeration with reduced energy consumption

    DOEpatents

    Gomes, Alberto Regio; Keres, Stephen L.; Kuehl, Steven J.; Litch, Andrew D.; Richmond, Peter J.; Wu, Guolian

    2015-09-22

    Methods of operation for refrigerator appliance configurations with a controller, a condenser, at least one evaporator, a compressor, and two refrigeration compartments. The configuration may be equipped with a variable-speed or variable-capacity compressor, variable speed evaporator or compartment fans, a damper, and/or a dual-temperature evaporator with a valve system to control flow of refrigerant through one or more pressure reduction devices. The methods may include synchronizing alternating cycles of cooling each compartment to a temperature approximately equal to the compartment set point temperature by operation of the compressor, fans, damper and/or valve system. The methods may also include controlling the cooling rate in one or both compartments. Refrigeration compartment cooling may begin at an interval before or after when the freezer compartment reaches its lower threshold temperature. Freezer compartment cooling may begin at an interval before or after when the freezer compartment reaches its upper threshold temperature.

  2. Fault-Tolerant, Multiple-Zone Temperature Control

    NASA Technical Reports Server (NTRS)

    Granger, James; Franklin, Brian; Michalik, Martin; Yates, Phillip; Peterson, Erik; Borders, James

    2008-01-01

    A computer program has been written as an essential part of an electronic temperature control system for a spaceborne instrument that contains several zones. The system was developed because the temperature and the rate of change of temperature in each zone are required to be maintained to within limits that amount to degrees of precision thought to be unattainable by use of simple bimetallic thermostats. The software collects temperature readings from six platinum resistance thermometers, calculates temperature errors from the readings, and implements a proportional + integral + derivative (PID) control algorithm that adjusts heater power levels. The software accepts, via a serial port, commands to change its operational parameters. The software attempts to detect and mitigate a host of potential faults. It is robust to many kinds of faults in that it can maintain PID control in the presence of those faults.

  3. Fiber Fabry-Perot interferometer with controllable temperature sensitivity.

    PubMed

    Zhang, Xinpu; Peng, Wei; Zhang, Yang

    2015-12-01

    We proposed a fiber taper based on the Fabry-Perot (FP) interferometer structure with controllable temperature sensitivity. The FP interferometer is formed by inserting a segment of tapered fiber tip into the capillary and subsequently splicing the other end of the capillary to a single-mode fiber (SMF), the tapered fiber endface, and the spliced face form the FP cavity. Through controlling the inserted tapered fiber length, a series of FP interferometers were made. Because the inserted taper tip has the degree of freedom along the fiber axial, when the FP interferometer is subjected to temperature variation, the thermal expansion of the fiber taper tip will resist the FP cavity length change caused by the evolution of capillary length, and we can control the temperature sensitivity by adjusting the inserted taper length. In this structure, the equivalent thermal expansion coefficient of the FP interferometer can be defined; it was used to evaluate the temperature sensitivity of the FP interferometer, which provides an effective method to eliminate the temperature effect and to enhance other measurement accuracy. We fabricated the FP interferometers and calibrated their temperature characters by measuring the wavelength shift of the resonance dips in the reflection spectrum. In a temperature range of 50°C to 150°C, the corresponding temperature sensitivities can be controlled between 0 and 1.97 pm/°C when the inserted taper is between 75 and 160 μm. Because of its controllable temperature sensitivity, ease of fabrication, and low cost, this FP interferometer can meet different temperature sensitivity requirements in various application areas, especially in the fields which need temperature insensitivity.

  4. Three calibration factors, applied to a rapid sweeping method, can accurately estimate Aedes aegypti (Diptera: Culicidae) pupal numbers in large water-storage containers at all temperatures at which dengue virus transmission occurs.

    PubMed

    Romero-Vivas, C M E; Llinás, H; Falconar, A K I

    2007-11-01

    The ability of a simple sweeping method, coupled to calibration factors, to accurately estimate the total numbers of Aedes aegypti (L.) (Diptera: Culicidae) pupae in water-storage containers (20-6412-liter capacities at different water levels) throughout their main dengue virus transmission temperature range was evaluated. Using this method, one set of three calibration factors were derived that could accurately estimate the total Ae. aegypti pupae in their principal breeding sites, large water-storage containers, found throughout the world. No significant differences were obtained using the method at different altitudes (14-1630 m above sea level) that included the range of temperatures (20-30 degrees C) at which dengue virus transmission occurs in the world. In addition, no significant differences were found in the results obtained between and within the 10 different teams that applied this method; therefore, this method was extremely robust. One person could estimate the Ae. aegypti pupae in each of the large water-storage containers in only 5 min by using this method, compared with two people requiring between 45 and 90 min to collect and count the total pupae population in each of them. Because the method was both rapid to perform and did not disturb the sediment layers in these domestic water-storage containers, it was more acceptable by the residents, and, therefore, ideally suited for routine surveillance purposes and to assess the efficacy of Ae. aegypti control programs in dengue virus-endemic areas throughout the world.

  5. Variable-thermoinsulation garments with a microprocessor temperature controller.

    PubMed

    Kurczewska, Agnieszka; Leánikowski, Jacek

    2008-01-01

    This paper presents the concept of active variable thermoinsulation clothing for users working in low temperatures. Those garments contain heating inserts regulated by a microprocessor temperature controller. This paper also presents the results of tests carried out on the newly designed garments.

  6. Weld Nugget Temperature Control in Thermal Stir Welding

    NASA Technical Reports Server (NTRS)

    Ding, R. Jeffrey (Inventor)

    2014-01-01

    A control system for a thermal stir welding system is provided. The control system includes a sensor and a controller. The sensor is coupled to the welding system's containment plate assembly and generates signals indicative of temperature of a region adjacent and parallel to the welding system's stir rod. The controller is coupled to the sensor and generates at least one control signal using the sensor signals indicative of temperature. The controller is also coupled to the welding system such that at least one of rotational speed of the stir rod, heat supplied by the welding system's induction heater, and feed speed of the welding system's weld material feeder are controlled based on the control signal(s).

  7. Numerical simulations and analyses of temperature control loop heat pipe for space CCD camera

    NASA Astrophysics Data System (ADS)

    Meng, Qingliang; Yang, Tao; Li, Chunlin

    2016-10-01

    As one of the key units of space CCD camera, the temperature range and stability of CCD components affect the image's indexes. Reasonable thermal design and robust thermal control devices are needed. One kind of temperature control loop heat pipe (TCLHP) is designed, which highly meets the thermal control requirements of CCD components. In order to study the dynamic behaviors of heat and mass transfer of TCLHP, particularly in the orbital flight case, a transient numerical model is developed by using the well-established empirical correlations for flow models within three dimensional thermal modeling. The temperature control principle and details of mathematical model are presented. The model is used to study operating state, flow and heat characteristics based upon the analyses of variations of temperature, pressure and quality under different operating modes and external heat flux variations. The results indicate that TCLHP can satisfy the thermal control requirements of CCD components well, and always ensure good temperature stability and uniformity. By comparison between flight data and simulated results, it is found that the model is to be accurate to within 1°C. The model can be better used for predicting and understanding the transient performance of TCLHP.

  8. Body temperature control in sepsis-induced acute lung injury.

    PubMed

    Wang, Giueng-Chueng; Chi, Wei-Ming; Perng, Wan-Cherng; Huang, Kun-Lun

    2003-12-31

    Body temperature is precisely regulated to maintain homeostasis in homeothermic animals. Although it remains unproved whether change of body temperature constitutes a beneficial or a detrimental component of the septic response, temperature control should be an important entity in septic experiments. We investigated the effect of body temperature control on the lipopolysaccharide (LPS)-induced lung injury. Acute lung injury in rats was induced by intratracheal spray of LPS and body temperature was either clamped at 37 degrees C for 5 hours or not controlled. The severity of lung injury was evaluated at the end of the experiment. Intratracheal administration of aerosolized LPS caused a persistent decline in body temperature and a significant lung injury as indicated by an elevation of protein-concentration and LDH activity in the bronchoalveolar lavage (BAL) fluid and wet/dry weight (W/D) ratio of lungs. Administration of LPS also caused neutrophil sequestration and lipid peroxidation in the lung tissue as indicated by increase in myeloperoxidase (MPO) activity and malondialdehyde (MDA) production, respectively. Control of body temperature at 37 degrees C after LPS (LPS/BT37, n = 11) significantly reduced acute lung injury as evidenced by decreases in BAL fluid protein concentration (983 +/- 189 vs. 1403 +/- 155 mg/L) and LDH activity (56 +/- 10 vs. 123 +/- 17 deltamAbs/min) compared with the LPS group (n = 11). Although the W/D ratio of lung and MDA level were lower in the rats received temperature control compared with those received LPS only, the differences were not statistically significant. Our results demonstrated that intratracheal administration of aerosolized LPS induced a hypothermic response and acute lung injury in rats and controlling body temperature at a normal range may alleviate the LPS-induced lung injury.

  9. Enhanced Temperature Control Method Using ANFIS with FPGA

    PubMed Central

    Zhou, Jun-Tin

    2014-01-01

    Temperature control in etching process is important for semiconductor manufacturing technology. However, pressure variations in vacuum chamber results in a change in temperature, worsening the accuracy of the temperature of the wafer and the speed and quality of the etching process. This work develops an adaptive network-based fuzzy inference system (ANFIS) using a field-programmable gate array (FPGA) to improve the effectiveness. The proposed method adjusts every membership function to keep the temperature in the chamber stable. The improvement of the proposed algorithm is confirmed using a medium vacuum (MV) inductively-coupled plasma- (ICP-) type etcher. PMID:24715808

  10. Heat pipes for spacecraft temperature control: Their usefulness and limitations

    NASA Technical Reports Server (NTRS)

    Ollendorf, S.; Stipandic, E.

    1972-01-01

    Heat pipes are used in spacecraft to equalize the temperature of structures and maintain temperature control of electronic components. Information is provided for a designer on: (1) a typical mounting technique, (2) choices available in wick geometries and fluids, (3) tests involved in flight-qualifying the design, and (4) heat pipe limitations. An evaluation of several heat pipe designs showed that the behavior of heat pipes at room temperature does not necessarily correlate with the classic equations used to predict their performance. They are sensitive to such parameters as temperature, fluid inventory, orientation, and noncondensable gases.

  11. Keep it cool: temperature priming effect on cognitive control.

    PubMed

    Halali, Eliran; Meiran, Nachshon; Shalev, Idit

    2017-03-01

    The effect of physical temperature on cognition and behavior has been the focus of extensive research in recent years, demonstrating that embodied concepts are grounded in, and shaped by, sensorimotor physical experiences. Nevertheless, less is known about how experienced and perceived temperatures affect cognitive control, one of humans core executive functions. In the present work, we primed participants with cool versus warm temperature using a between participants manipulation of physical touch experience (Experiment 1), and a within participants manipulation of seeing landscape views associated with cool vs. warm temperatures (Experiment 2). In both experiments, cool compared to warm temperatures lead to improved performance on an anti-saccade task, an established cognitive control measure. Implications are discussed.

  12. Ion Temperature Control of the Io Plasma Torus

    NASA Technical Reports Server (NTRS)

    Delamere, P. A.; Schneider, N. M.; Steffl, A. J.; Robbins, S. J.

    2005-01-01

    We report on observational and theoretical studies of ion temperature in the Io plasma torus. Ion temperature is a critical factor for two reasons. First, ions are a major supplier of energy to the torus electrons which power the intense EUV emissions. Second, ion temperature determines the vertical extent of plasma along field lines. Higher temperatures spread plasma out, lowers the density and slows reaction rates. The combined effects can play a controlling role in torus energetics and chemistry. An unexpected tool for the study of ion temperature is the longitudinal structure in the plasma torus which often manifests itself as periodic brightness variations. Opposite sides of the torus (especially magnetic longitudes 20 and 200 degrees) have been observed on numerous occasions to have dramatically different brightness, density, composition, ionization state, electron temperature and ion temperature. These asymmetries must ultimately be driven by different energy flows on the opposite sides, presenting an opportunity to observe key torus processes operating under different conditions. The most comprehensive dataset for the study of longitudinal variations was obtained by the Cassini UVIS instrument during its Jupiter flyby. Steffl (Ph.D. thesis, 2005) identified longitudinal variations in all the quantities listed above wit the exception of ion temperature. We extend his work by undertaking the first search for such variation in the UVIS dataset. We also report on a 'square centimeter' model of the torus which extend the traditional 'cubic centimeter' models by including the controlling effects of ion temperature more completely.

  13. A liquid cooled garment temperature controller based on sweat rate

    NASA Technical Reports Server (NTRS)

    Chambers, A. B.; Blackaby, J. R.

    1972-01-01

    An automatic controller for liquid cooled space suits is reported that utilizes human sweat rate as the primary input signal. The controller is so designed that the coolant inlet temperature is inversely proportional to the subject's latent heat loss as evidenced by evaporative water loss.

  14. Solid-state Distributed Temperature Control for International Space Station

    NASA Technical Reports Server (NTRS)

    Holladay, Jon B.; Reagan, Shawn E.; Day, Greg

    2004-01-01

    A newly developed solid-state temperature controller will offer greater flexibility in the thermal control of aerospace vehicle structures. A status of the hardware development along with its implementation on the Multi- Purpose Logistics Module will be provided. Numerous advantages of the device will also be discussed with regards to current and future flight vehicle implementations.

  15. Temperature control system for a J-module heat exchanger

    DOEpatents

    Basdekas, Demetrios L.; Macrae, George; Walsh, Joseph M.

    1978-01-01

    The level of primary fluid is controlled to change the effective heat transfer area of a heat exchanger utilized in a liquid metal nuclear power plant to eliminate the need for liquid metal control valves to regulate the flow of primary fluid and the temperature of the effluent secondary fluid.

  16. Riparian Vegetation Control of In-Stream Temperature

    NASA Astrophysics Data System (ADS)

    Davies, P. M.

    2005-05-01

    Stream temperature is an important physical characteristic that can control the structure of aquatic fauna and influence key ecological processes. The response of in-stream temperature to topographic and vegetative shade can be predicted with reasonable accuracy at the sub-catchment scale. A more difficult task is to determine the biotic response to thermal stress and therefore set guideline values. A series of LD50 experiments supported extensive worldwide literature on temperature tolerances of aquatic fauna. Temperature modelling was applied at different biogeographic zones of Australia. In Mediterranean climates where low flow corresponded with high summer air temperatures, in-stream thermal stress was highly seasonal. In the tropics the situation was reversed such that high air temperatures, during summer, corresponded with high stream flows that moderated the magnitude of seasonal variation. When combined with the estimated thermal tolerance of selected taxa, model analyses identified critical bottlenecks, in space and time, and enabled prioritisation of riparian restoration efforts.

  17. Method and apparatus for controlling the temperature in thermoforming machines

    SciTech Connect

    Janke, J.

    1985-04-02

    The temperature of upper and lower parts of a forming tool making deep-drawn thermoplastic articles is controlled with a system which performs the steps of passing a coolant of predetermined total volume through the upper part and the lower part of the forming tool; measuring the temperature of the upper and lower parts; determining the actual temperature difference between the upper and lower parts; comparing the actual temperature difference with a predetermined desired temperature difference; generating a signal representing the magnitude of deviation between the actual and desired temperature differences; and, as a function of the signal, increasing the volume of coolant passing through one of the forming tool parts and decreasing the volume of coolant passing through the other of the forming tool parts for reducing the magnitude of deviation while maintaining the total volume unchanged.

  18. Temperature control of power semiconductor devices in traction applications

    NASA Astrophysics Data System (ADS)

    Pugachev, A. A.; Strekalov, N. N.

    2017-02-01

    The peculiarity of thermal management of traction frequency converters of a railway rolling stock is highlighted. The topology and the operation principle of the automatic temperature control system of power semiconductor modules of the traction frequency converter are designed and discussed. The features of semiconductors as an object of temperature control are considered; the equivalent circuit of thermal processes in the semiconductors is suggested, the power losses in the two-level voltage source inverters are evaluated and analyzed. The dynamic properties and characteristics of the cooling fan induction motor electric drive with the scalar control are presented. The results of simulation in Matlab are shown for the steady state of thermal processes.

  19. Active disturbance rejection control of temperature for ultrastable optical cavities.

    PubMed

    Pizzocaro, Marco; Calonico, Davide; Calosso, Claudio; Clivati, Cecilia; Costanzo, Giovanni A; Levi, Filippo; Mura, Alberto

    2013-02-01

    This paper describes the application of a novel active disturbance rejection control (ADRC) to the stabilization of the temperature of two ultra-stable Fabry-Perot cavities. The cavities are 10 cm long and entirely made of ultralow- expansion glass. The control is based on a linear extended state observer that estimates and compensates the disturbance in the system in real time. The resulting control is inherently robust and easy to tune. A digital implementation of ADRC gives a temperature instability of 200 μK at one day of integration time.

  20. Data Assimilation Experiments using Quality Controlled AIRS Version 5 Temperature Soundings

    NASA Technical Reports Server (NTRS)

    Susskind, Joel

    2008-01-01

    The AIRS Science Team Version 5 retrieval algorithm has been finalized and is now operational at the Goddard DAAC in the processing (and reprocessing) of all AlRS data. Version 5 contains accurate case-by-case error estimates for most derived products, which are also used for quality control. We have conducted forecast impact experiments assimilating AlRS quality controlled temperature profiles using the NASA GEOS-5 data assimilation system, consisting of the NCEP GSI analysis coupled with the NASA FVGCM. Assimilation of quality controlled temperature profiles resulted in significantly improved forecast skill in both the Northern Hemisphere and Southern Hemisphere Extra-Tropics, compared to that obtained from analyses obtained when all data used operationally by NCEP except for AlRS data is assimilated. Experiments using different Quality Control thresholds for assimilation of AlRS temperature retrievals showed that a medium quality control threshold performed better than a tighter threshold, which provided better overall sounding accuracy; or a looser threshold, which provided better spatial coverage of accepted soundings. We are conducting more experiments to further optimize this balance of spatial coverage and sounding accuracy from the data assimilation perspective. In all cases, temperature soundings were assimilated well below cloud level in partially cloudy cases. The positive impact of assimilating AlRS derived atmospheric temperatures all but vanished when only AIRS stratospheric temperatures were assimilated. Forecast skill resulting from assimilation of AlRS radiances uncontaminated by clouds, instead of AlRS temperature soundings, was only slightly better than that resulting from assimilation of only stratospheric AlRS temperatures. This reduction in forecast skill is most likely the result of significant loss of tropospheric information when only AIRS radiances unaffected by clouds are used in the data assimilation process.

  1. Finger temperature controller for non-invasive blood glucose measurement

    NASA Astrophysics Data System (ADS)

    Zhang, Xiqin; Ting, Choon Meng; Yeo, Joon Hock

    2010-11-01

    Blood glucose level is an important parameter for doctors to diagnose and treat diabetes. The Near-Infra-Red (NIR) spectroscopy method is the most promising approach and this involves measurement on the body skin. However it is noted that the skin temperature does fluctuate with the environmental and physiological conditions and we found that temperature has important influences on the glucose measurement. In-vitro and in-vivo investigations on the temperature influence on blood glucose measurement have been carried out. The in-vitro results show that water temperature has significant influence on water absorption. Since 90% of blood components are water, skin temperature of measurement site has significant influence on blood glucose measurement. Also the skin temperature is related to the blood volume, blood volume inside capillary vessels changes with skin temperature. In this paper the relationship of skin temperature and signal from the skin and inside tissue was studied at different finger temperatures. Our OGTT (oral glucose tolerance test) trials results show the laser signals follow the skin temperature trend and the correlation of signal and skin temperature is much stronger than the correlation of signal and glucose concentration. A finger heater device is designed to heat and maintain the skin temperature of measurement site. The heater is controlled by an electronic circuit according to the skin temperature sensed by a thermocouple that is put close to the measurement site. In vivo trials were carried out and the results show that the skin temperature significantly influences the signal fluctuations caused by pulsate blood and the average signal value.

  2. Heat pipe temperature control utilizing a soluble gas absorption reservior

    NASA Technical Reports Server (NTRS)

    Saaski, E. W.

    1976-01-01

    A new gas-controlled heat pipe design is described which uses a liquid matrix reservior, or sponge, to replace the standard gas reservior. Reservior volume may be reduced by a factor of five to ten for certain gas-liquid combinations, while retaining the same level of temperature control. Experiments with ammonia, butane, and carbon dioxide control gases with methanol working fluid are discussed.

  3. Modeling Validation and Control Analysis for Controlled Temperature and Humidity of Air Conditioning System

    PubMed Central

    Lee, Jing-Nang; Lin, Tsung-Min

    2014-01-01

    This study constructs an energy based model of thermal system for controlled temperature and humidity air conditioning system, and introduces the influence of the mass flow rate, heater and humidifier for proposed control criteria to achieve the controlled temperature and humidity of air conditioning system. Then, the reliability of proposed thermal system model is established by both MATLAB dynamic simulation and the literature validation. Finally, the PID control strategy is applied for controlling the air mass flow rate, humidifying capacity, and heating, capacity. The simulation results show that the temperature and humidity are stable at 541 sec, the disturbance of temperature is only 0.14°C, 0006 kgw/kgda in steady-state error of humidity ratio, and the error rate is only 7.5%. The results prove that the proposed system is an effective controlled temperature and humidity of an air conditioning system. PMID:25250390

  4. Modeling validation and control analysis for controlled temperature and humidity of air conditioning system.

    PubMed

    Lee, Jing-Nang; Lin, Tsung-Min; Chen, Chien-Chih

    2014-01-01

    This study constructs an energy based model of thermal system for controlled temperature and humidity air conditioning system, and introduces the influence of the mass flow rate, heater and humidifier for proposed control criteria to achieve the controlled temperature and humidity of air conditioning system. Then, the reliability of proposed thermal system model is established by both MATLAB dynamic simulation and the literature validation. Finally, the PID control strategy is applied for controlling the air mass flow rate, humidifying capacity, and heating, capacity. The simulation results show that the temperature and humidity are stable at 541 sec, the disturbance of temperature is only 0.14 °C, 0006 kg(w)/kg(da) in steady-state error of humidity ratio, and the error rate is only 7.5%. The results prove that the proposed system is an effective controlled temperature and humidity of an air conditioning system.

  5. Regulation of Silk Material Structure by Temperature-Controlled Water Vapor Annealing

    PubMed Central

    Hu, Xiao; Shmelev, Karen; Sun, Lin; Gil, Eun-Seok; Park, Sang-Hyug; Cebe, Peggy; Kaplan, David L.

    2011-01-01

    We present a simple and effective method to obtain refined control of the molecular structure of silk biomaterials through physical temperature-controlled water vapor annealing (TCWVA). The silk materials can be prepared with control of crystallinity, from a low content using conditions at 4°C (alpha-helix dominated silk I structure), to highest content of ~60% crystallinity at 100°C (beta-sheet dominated silk II structure). This new physical approach covers the range of structures previously reported to govern crystallization during the fabrication of silk materials, yet offers a simpler, green chemistry, approach with tight control of reproducibility. The transition kinetics, thermal, mechanical, and biodegradation properties of the silk films prepared at different temperatures were investigated and compared by Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), uniaxial tensile studies, and enzymatic degradation studies. The results revealed that this new physical processing method accurately controls structure, in turn providing control of mechanical properties, thermal stability, enzyme degradation rate, and human mesenchymal stem cell interactions. The mechanistic basis for the control is through the temperature controlled regulation of water vapor, to control crystallization. Control of silk structure via TCWVA represents a significant improvement in the fabrication of silk-based biomaterials, where control of structure-property relationships is key to regulating material properties. This new approach to control crystallization also provides an entirely new green approach, avoiding common methods which use organic solvents (methanol, ethanol) or organic acids. The method described here for silk proteins would also be universal for many other structural proteins (and likely other biopolymers), where water controls chain interactions related to material properties. PMID:21425769

  6. Control and Room Temperature Optimization of Energy Efficient Buildings

    SciTech Connect

    Djouadi, Seddik M; Kuruganti, Phani Teja

    2012-01-01

    The building sector consumes a large part of the energy used in the United States and is responsible for nearly 40% of greenhouse gas emissions. It is therefore economically and environmentally important to reduce the building energy consumption to realize massive energy savings. In this paper, a method to control room temperature in buildings is proposed. The approach is based on a distributed parameter model represented by a three dimensional (3D) heat equation in a room with heater/cooler located at ceiling. The latter is resolved using finite element methods, and results in a model for room temperature with thousands of states. The latter is not amenable to control design. A reduced order model of only few states is then derived using Proper Orthogonal Decomposition (POD). A Linear Quadratic Regulator (LQR) is computed based on the reduced model, and applied to the full order model to control room temperature.

  7. Temperature control system for optical elements in astronomical instrumentation

    NASA Astrophysics Data System (ADS)

    Verducci, Orlando; de Oliveira, Antonio C.; Ribeiro, Flávio F.; Vital de Arruda, Márcio; Gneiding, Clemens D.; Fraga, Luciano

    2014-07-01

    Extremely low temperatures may damage the optical components assembled inside of an astronomical instrument due to the crack in the resin or glue used to attach lenses and mirrors. The environment, very cold and dry, in most of the astronomical observatories contributes to this problem. This paper describes the solution implemented at SOAR for remotely monitoring and controlling temperatures inside of a spectrograph, in order to prevent a possible damage of the optical parts. The system automatically switches on and off some heat dissipation elements, located near the optics, as the measured temperature reaches a trigger value. This value is set to a temperature at which the instrument is not operational to prevent malfunction and only to protect the optics. The software was developed with LabVIEWTM and based on an object-oriented design that offers flexibility and ease of maintenance. As result, the system is able to keep the internal temperature of the instrument above a chosen limit, except perhaps during the response time, due to inertia of the temperature. This inertia can be controlled and even avoided by choosing the correct amount of heat dissipation and location of the thermal elements. A log file records the measured temperature values by the system for operation analysis.

  8. Rapid control of mold temperature during injection molding process

    SciTech Connect

    Liparoti, Sara; Titomanlio, Giuseppe; Hunag, Tsang Min; Cakmak, Mukerrem; Sorrentino, Andrea

    2015-05-22

    The control of mold surface temperature is an important factor that determines surface morphology and its dimension in thickness direction. It can also affect the frozen molecular orientation and the mold surface replicability in injection molded products. In this work, thin thermally active films were used to quickly control the mold surface temperature. In particular, an active high electrical conductivity carbon black loaded polyimide composites sandwiched between two insulating thin polymeric layers was used to condition the mold surface. By controlling the heating time, it was possible to control precisely the temporal variation of the mold temperature surface during the entire cycle. The surface heating rate was about 40°C/s and upon contact with the polymer the surface temperature decreased back to 40°C within about 5 s; the overall cycle time increased only slightly. The effect on cross section sample morphology of samples of iPP were analyzed and discussed on the basis of the recorded temperature evolution.

  9. A New Method for Controlling Billet Temperature During Isothermal Die Forging of a Complex Superalloy Casing

    NASA Astrophysics Data System (ADS)

    Lin, Y. C.; Wu, Xian-Yang

    2015-09-01

    Isothermal die forging is one of near net-shape metal-forming technologies. Strict control of billet temperature during isothermal die forging is a guarantee for the excellent properties of final product. In this study, a new method is proposed to accurately control the billet temperature of complex superalloy casing, based on the finite element simulation and response surface methodology (RSM). The proposed method is accomplished by the following two steps. Firstly, the thermal compensation process is designed and optimized to overcome the inevitable heat loss of dies during hot forging. i.e., the layout and opening time of heaters assembled on die sleeves are optimized. Then, the effects of forging speed (the pressing velocity of hydraulic machine) and its changing time on the maximum billet temperature are discussed. Furthermore, the optimized forging speed and its changing time are obtained by RSM. Comparisons between the optimized and conventional die forging processes indicate that the proposed method can effectively control the billet temperature within the optimal forming temperature range. So, the optimized die forging processes can guarantee the high volume fraction of dynamic recrystallization, and restrict the rapid growth of grains in the forged superalloy casing.

  10. Accurate control of a liquid-crystal display to produce a homogenized Fourier transform for holographic memories.

    PubMed

    Márquez, Andrés; Gallego, Sergi; Méndez, David; Alvarez, Mariela L; Fernández, Elena; Ortuño, Manuel; Neipp, Cristian; Beléndez, Augusto; Pascual, Inmaculada

    2007-09-01

    We show an accurate procedure to obtain a Fourier transform (FT) with no dc term using a commercial twisted-nematic liquid-crystal display. We focus on the application to holographic storage of binary data pages, where a drastic decrease of the dc term in the FT is highly desirable. Two different codification schemes are considered: binary pi radians phase modulation and hybrid ternary modulation. Any deviation in the values of the amplitude and phase shift generates the appearance of a strong dc term. Experimental results confirm that the calculated configurations provide a FT with no dc term, thus showing the effectiveness of the proposal.

  11. Thermoelectrically controlled device for studies of temperature-induced corneal shrinkage

    NASA Astrophysics Data System (ADS)

    Borja, David; Manns, Fabrice; Fernandez, Viviana; Lamar, Peggy; Soederberg, Per G.; Parel, Jean-Marie A.

    2002-06-01

    The purpose of this study was to design and calibrate a device to measure the dynamics of thermal shrinkage in corneal and scleral strips. The apparatus consists of a thermoelectric cell controlled by a temperature controller designed to generate temperatures up to 90 degree(s)C in rectangular corneal strips; a copper cuvette filled with Dextran solution that holds the corneal strip and a displacement sensor that measures the change in length of the tissue during heat-induced shrinkage. The device was tested on corneal tissue from Florida Eye-Bank eyes that were cut into 2x4mm rectangular strips. Preliminary results indicate that our system can reproducibly create and accurately measure thermally induced corneal shrinkage. Shrinkage experiments will be used to optimize laser parameters for corneal shrinkage during laser thermokeratoplasty and laser scleral buckling.

  12. Instrument-free exothermic heating with phase change temperature control for paper microfluidic devices

    PubMed Central

    Singleton, Jered; Zentner, Chris; Buser, Josh; Yager, Paul; LaBarre, Paul; Weigl, Bernhard H.

    2014-01-01

    Many infectious diseases, as well as some cancers, that affect global health are most accurately diagnosed through nucleic acid amplification and detection. There is a great need to simplify nucleic acid-based assay systems for use in global health in low-resource settings as well as in settings that do not have convenient access to laboratory staff and equipment such as doctors' offices and home care settings. In developing countries, unreliable electric power, inadequate supply chains, and lack of maintenance for complex diagnostic instruments are all common infrastructure shortfalls. Many elements of instrument-free, disposable, nucleic acid amplification assays have been demonstrated in recent years. However, the problem of instrument-free,1 low-cost, temperature-controlled chemical heating remains unsolved. In this paper we present the current status and results of work towards developing disposable, low-cost, temperature-controlled heaters designed to support isothermal nucleic acid amplification assays that are integrated with a two-dimensional paper network. Our approach utilizes the heat generated through exothermic chemical reactions and controls the heat through use of engineered phase change materials to enable sustained temperatures required for nucleic acid amplification. By selecting appropriate exothermic and phase change materials, temperatures can be controlled over a wide range, suitable for various isothermal amplification methods, and maintained for over an hour at an accuracy of +/- 1°C. PMID:25426269

  13. Study on Control of Brain Temperature for Brain Hypothermia Treatment

    NASA Astrophysics Data System (ADS)

    Gaohua, Lu; Wakamatsu, Hidetoshi

    The brain hypothermia treatment is an attractive therapy for the neurologist because of its neuroprotection in hypoxic-ischemic encephalopathy patients. The present paper deals with the possibility of controlling the brain and other viscera in different temperatures from the viewpoint of system control. It is theoretically attempted to realize the special brain hypothermia treatment to cool only the head but to warm the body by using the simple apparatus such as the cooling cap, muffler and warming blanket. For this purpose, a biothermal system concerning the temperature difference between the brain and the other thoracico-abdominal viscus is synthesized from the biothermal model of hypothermic patient. The output controllability and the asymptotic stability of the system are examined on the basis of its structure. Then, the maximum temperature difference to be realized is shown dependent on the temperature range of the apparatus and also on the maximum gain determined from the coefficient matrices A, B and C of the biothermal system. Its theoretical analysis shows the realization of difference of about 2.5°C, if there is absolutely no constraint of the temperatures of the cooling cap, muffler and blanket. It is, however, physically unavailable. Those are shown by simulation example of the optimal brain temperature regulation using a standard adult database. It is thus concluded that the surface cooling and warming apparatus do no make it possible to realize the special brain hypothermia treatment, because the brain temperature cannot be cooled lower than those of other viscera in an appropriate temperature environment. This study shows that the ever-proposed good method of clinical treatment is in principle impossible in the actual brain hypothermia treatment.

  14. Data Assimilation Experiments Using Quality Controlled AIRS Version 5 Temperature Soundings

    NASA Technical Reports Server (NTRS)

    Susskind, Joel

    2009-01-01

    The AIRS Science Team Version 5 retrieval algorithm has been finalized and is now operational at the Goddard DAAC in the processing (and reprocessing) of all AIRS data. The AIRS Science Team Version 5 retrieval algorithm contains a number of significant improvements over Version 4. Two very significant improvements are described briefly below. 1) The AIRS Science Team Radiative Transfer Algorithm (RTA) has now been upgraded to accurately account for effects of non-local thermodynamic equilibrium on the AIRS observations. This allows for use of AIRS observations in the entire 4.3 micron CO2 absorption band in the retrieval algorithm during both day and night. Following theoretical considerations, tropospheric temperature profile information is obtained almost exclusively from clear column radiances in the 4.3 micron CO2 band in the AIRS Version 5 temperature profile retrieval step. These clear column radiances are a derived product that are indicative of radiances AIRS channels would have seen if the field of view were completely clear. Clear column radiances for all channels are determined using tropospheric sounding 15 micron CO2 observations. This approach allows for the generation of accurate values of clear column radiances and T(p) under most cloud conditions. 2) Another very significant improvement in Version 5 is the ability to generate accurate case-by-case, level-by-level error estimates for the atmospheric temperature profile, as well as for channel-by-channel clear column radiances. These error estimates are used for quality control of the retrieved products. Based on error estimate thresholds, each temperature profiles is assigned a characteristic pressure, pg, down to which the profile is characterized as good for use for data assimilation purposes. We have conducted forecast impact experiments assimilating AIRS quality controlled temperature profiles using the NASA GEOS-5 data assimilation system, consisting of the NCEP GSI analysis coupled with the

  15. Temperature Controlled Laser Joining of Aluminum to Galvanized Steel

    NASA Astrophysics Data System (ADS)

    Weller, Daniel; Simon, Jörg; Stritt, Peter; Weber, Rudolf; Graf, Thomas; Bezençon, Cyrille; Bassi, Corrado

    Reliable joining of 6000 series aluminum alloy to galvanized steel is a challenge for current manufacturing technologies. To control and limit the formation of brittle intermetallic phases, mixing of both metals in liquid state has to be avoided. It has been shown that laser weld-brazing is a possible process. Thereby the aluminum and zinc layer of the galvanized steel are molten and the steel remains solid during the process. In addition, to avoid zinc degassing, the aluminum melt bath temperature has to be below zinc boiling temperature of 907°C. To meet these requirements a temperature controlled laser process was developed, allowing to join the two materials without flux and filler material. The thickness of the intermetallic layer shows a dependency on the set temperature used to control the process. At optimum set temperature the thickness of intermetallic phases can be limited to about 5 μm. Tensile strengths of the joints of up to 75% of the aluminum base material were achieved.

  16. High Temperature Evaluation of an Active Clearance Control System Concept

    NASA Technical Reports Server (NTRS)

    Taylor, Shawn C.; Steinetz, Bruce M.; Oswald, Jay J.

    2006-01-01

    A mechanically actuated blade tip clearance control concept was evaluated in a nonrotating test rig to quantify secondary seal leakage at elevated temperatures. These tests were conducted to further investigate the feasibility of actively controlling the clearance between the rotor blade tips and the surrounding shroud seal in the high pressure turbine (HPT) section of a turbine engine. The test environment simulates the state of the back side of the HPT shroud seal with pressure differentials as high as 120 psig and temperatures up to 1000 F. As expected, static secondary seal leakage decreased with increasing temperature. At 1000 F, the test rig's calculated effective clearance (at 120 psig test pressure) was 0.0003 in., well within the industry specified effective clearance goal.

  17. Temperature control of microheaters for localized carbon nanotube synthesis.

    PubMed

    Lu, Jingyu; Xu, Ting; Miao, Jianmin

    2011-12-01

    The temperatures of microheater devices for the localized growth of carbon nanotubes (CNTs) were brought under control to a great extent by providing the appropriate electric load (direct current or voltage) to the microheater circuit. The electrical-thermal coupled field simulations show that high temperatures only appear in very local areas under certain electric load. The infrared image of the produced microheater device agrees well with the simulation results. By applying the selected current to the fabricated microheater device and providing the mixed reaction gases, long, dense, and vertically well aligned CNT bundles were successfully grown very locally on the substrate. The control of temperatures paves the way to the localized growth of CNTs with good compatibility with CMOS process, and thus facilitating the direct integration of CNTs into future micro/nano electronics as interconnects. What's more, the method will also excite more in depth investigations on the applications of microheaters in many other fields.

  18. A portable device for temperature control along microchannels.

    PubMed

    Vigolo, Daniele; Rusconi, Roberto; Piazza, Roberto; Stone, Howard A

    2010-03-21

    For many physical, chemical and biological measurements, temperature is a crucial parameter to control. In particular, the recent development of microreactors and chip-based technologies requires integrated thermostatic systems. However, the requirements of disposability and visual inspection of a device under a microscope cannot accommodate equipment such as external heaters. By exploiting a silver-filled epoxy that can be injected and solidified in a microfluidic chip, we demonstrate a simple and inexpensive design of a conductive path, which allows heating by the Joule effect of both sides of a microchannel. In addition to permitting the maintenance of a constant temperature along the channel walls, our method can control the temperature gradient across the channel, thus enabling non-equilibrium studies in a microfluidic geometry.

  19. Control of matric water potential by temperature differential

    NASA Technical Reports Server (NTRS)

    Palmer, R. J. Jr; Nienow, J. A.; Friedmann, E. I.

    1987-01-01

    A method for controlling relative humidity based on temperature differentials, rather than on salt solutions, is described. This method has the following advantages: (1) it does not exhibit the anomalous CO2 solution effects that we have found to occur with salt solutions; (2) humidity is continuously adjustable without sample removal; (3) circulation of the atmosphere results in short equilibration times.

  20. 93. TEMPERATURE AND FLOW RATE CONTROLS FOR SYSTEM 1 AND ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    93. TEMPERATURE AND FLOW RATE CONTROLS FOR SYSTEM 1 AND SYSTEM 2, FACING WEST IN MECHANICAL EQUIPMENT ROOM (101), LSB (BLDG. 770) - Vandenberg Air Force Base, Space Launch Complex 3, Launch Pad 3 West, Napa & Alden Roads, Lompoc, Santa Barbara County, CA

  1. Auxiliary coil controls temperature of RF induction heater

    NASA Technical Reports Server (NTRS)

    1966-01-01

    Auxiliary coil controls the temperature of an RF induction furnace that is powered by a relatively unstable RF generator. Manual or servoed adjustments of the relative position of the auxiliary coil, which is placed in close proximity to the RF coil, changes the looseness of the RF coil and hence the corresponding heating effect of its RF field.

  2. A Reliable, Inexpensive Proportional Temperature Controller and Differential Thermometer.

    ERIC Educational Resources Information Center

    Badger, Robert C.

    1978-01-01

    Describes the construction of an inexpensive, highly reliable, milli-degree temperature controller and differential thermometer from an extremely stable thermistor and other readily available materials. Actual construction time is relatively short for both devices. Illustrations are included. (Author/MA)

  3. Temperature and humidity control in indirect calorimeter chambers

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A three-chamber, indirect calorimeter has been a part of the Environmental Laboratory at the U.S. Meat Animal Research Center (MARC) for over 25 yr. Corrosion of the animal chambers and unreliable temperature control forced either major repairs or complete replacement. There is a strong demand for...

  4. Temperature-controlled molecular depolarization gates in nuclear magnetic resonance

    SciTech Connect

    Schroder, Leif; Schroder, Leif; Chavez, Lana; Meldrum, Tyler; Smith, Monica; Lowery, Thomas J.; E. Wemmer, David; Pines, Alexander

    2008-02-27

    Down the drain: Cryptophane cages in combination with selective radiofrequency spin labeling can be used as molecular 'transpletor' units for transferring depletion of spin polarization from a hyperpolarized 'source' spin ensemble to a 'drain' ensemble. The flow of nuclei through the gate is adjustable by the ambient temperature, thereby enabling controlled consumption of hyperpolarization.

  5. Temperature-dependent liquid metal flowrate control device

    DOEpatents

    Carlson, Roger D.

    1978-01-01

    A temperature-dependent liquid metal flowrate control device includes a magnet and a ferromagnetic member defining therebetween a flow path for liquid metal, the ferromagnetic member being formed of a material having a curie temperature at which a change in the flow rate of the liquid metal is desired. According to the preferred embodiment the magnet is a cylindrical rod magnet axially disposed within a cylindrical member formed of a curie material and having iron pole pieces at the ends. A cylindrical iron shunt and a thin wall stainless steel barrier are disposed in the annulus between magnet and curie material. Below the curie temperature flow between steel barrier and curie material is impeded and above the curie temperature flow impedance is reduced.

  6. Hollow glass microspheres for temperature and irradiance control in photobioreactors.

    PubMed

    Pereira, Darlan A; José, Nadia M; Villamizar, Sonia M G; Sales, Emerson A; Perelo, Louisa W

    2014-04-01

    The addition of hollow glass microspheres (HGM) to polymers to change thermal insulation and mechanical properties is widely used. In this study HGM were tested as a new construction material for photobioreactors to control irradiance and broth temperature in microalgae cultivation. The heat isolation properties of HGMs of three different densities were tested in a polymer matrix. The transmittance (5-50%) and the thermal conductivity (182.05-190.73 W/mK) of the HGM composite material were analyzed. The results were tested in a model to predict the broth temperature and the growth rate as a function of temperature and irradiance. The addition of 1.3 and 0.6 vol.% of HGM lead to an increase in the growth rate of up to 37% and a reduction in the broth temperature up to 9°C. The mechanical resistance of the composites tested is similar to the polymer matrix.

  7. PARTICLE ACCELERATOR AND METHOD OF CONTROLLING THE TEMPERATURE THEREOF

    DOEpatents

    Neal, R.B.; Gallagher, W.J.

    1960-10-11

    A method and means for controlling the temperature of a particle accelerator and more particularly to the maintenance of a constant and uniform temperature throughout a particle accelerator is offered. The novel feature of the invention resides in the provision of two individual heating applications to the accelerator structure. The first heating application provided is substantially a duplication of the accelerator heat created from energization, this first application being employed only when the accelerator is de-energized thereby maintaining the accelerator temperature constant with regard to time whether the accelerator is energized or not. The second heating application provided is designed to add to either the first application or energization heat in a manner to create the same uniform temperature throughout all portions of the accelerator.

  8. Control Performance of ER Engine Mount Subjected to Temperature Variations

    NASA Astrophysics Data System (ADS)

    Song, H. J.; Choi, S. B.; Kim, K. S.

    A key function of engine mount of vehicle systems is to support engine mass and isolate noise and vibration from engine disturbance forces. One of attractive candidates to achieve this goal is to utilize a semi-active ER engine mount. By applying this, we can effectively control damping force and hence the noise and vibration by just controlling the intensity of electric field. However, control performance of the engine mount may be very sensitive to temperature variation during engine operation. In this work, we investigate dynamic and control performances of ER engine mount with respect to the temperature variation. In order to undertake this, a flow-mode type of ER engine mount is designed and manufactured. Displacement transmissibility is experimentally evaluated for 1 degree of freedom. The ER engine mount is then incorporated with full-vehicle model in order to investigate vibration control performance. After formulating the governing equation of motion, a semi-active controller is designed. The controller is implemented through a hardware-in-the-loop simulation (HILS), and control responses such as acceleration level at various engine speeds are evaluated in the frequency and time domains.

  9. Characterization of a temperature-controlled FAIMS system.

    PubMed

    Barnett, David A; Belford, Michael; Dunyach, Jean-Jacques; Purves, Randy W

    2007-09-01

    High-field asymmetric waveform ion mobility spectrometry (FAIMS) focuses and separates gas-phase analyte ions from chemical background, offering substantial improvements in the detection of targeted species in biological matrices. Ion separations have been typically performed at atmospheric pressure and ambient temperature, although routine small molecule quantitation by LC-MS (and thus LC-FAIMS-MS) is generally performed at liquid flow rates (e.g., in excess of 200 microL/min) in which atmospheric pressure ionization sources (e.g., APCI and ESI) need to be run at elevated temperatures to enhance ion desolvation. Heat from the ionization source and/or the mass spectrometer capillary interface is shown to have a significant impact on the performance of a conventional FAIMS electrode set. This study introduces a new FAIMS system that uses gas heating/cooling to quickly reach temperature equilibrium independent of the external temperature conditions. A series of equations and balance plots, which look at the effect of temperature and other variables, on the normalized field strength (E/N), are introduced and used to explain experimental observations. Examples where the ion behavior deviates from the predicted behavior are presented and explanations based on clusters or changes in ion-neutral interactions are given. Consequences of the use of temperature control, and in particular advantages of using different temperature settings on the inner and outer electrodes, for the purpose of manipulating ion separation are described.

  10. Field Test of Boiler Primary Loop Temperature Controller

    SciTech Connect

    Glanville, P.; Rowley, P.; Schroeder, D.; Brand, L.

    2014-09-01

    Beyond these initial system efficiency upgrades are an emerging class of Advanced Load Monitoring (ALM) aftermarket controllers that dynamically respond to the boiler load, with claims of 10% to 30% of fuel savings over a heating season. For hydronic boilers specifically, these devices perform load monitoring, with continuous measurement of supply and, in some cases, return water temperatures. Energy savings from these ALM controllers are derived from dynamic management of the boiler differential, where a microprocessor with memory of past boiler cycles prevents the boiler from firing for a period of time, to limit cycling losses and inefficient operation during perceived low load conditions. These differ from OTR controllers, which vary boiler setpoint temperatures with ambient conditions while maintaining a fixed differential.

  11. Temperature and oxygen visual estimator for carbonization process control

    NASA Astrophysics Data System (ADS)

    Martínez, Fredy; Martínez, Fernando; Montiel, Holman

    2017-02-01

    This paper proposes a visual estimator for temperature and oxygen content for closed loop control of carbonization furnace in the production of activated carbon. The carbonization process involves thermal decomposition of vegetal material in the absence of air; this requires rigorous sensing and control of these two variables. The system consists of two cameras, a thermographic camera to estimate the temperature, and a traditional digital camera to estimate the oxygen content. In both cases we use similarity measures between images to estimate the value of the variables into the furnace, estimation that is used to control the furnace flame. The algorithm is tested with reference photos taken at the production plant, and the experimental results prove the performance of the proposed technique.

  12. Improving Forecast Skill by Assimilation of Quality Controlled AIRS Version 5 Temperature Soundings

    NASA Technical Reports Server (NTRS)

    Susskind, Joel; Reale, Oreste

    2009-01-01

    The AIRS Science Team Version 5 retrieval algorithm has been finalized and is now operational at the Goddard DAAC in the processing (and reprocessing) of all AIRS data. The AIRS Science Team Version 5 retrieval algorithm contains two significant improvements over Version 4: 1) Improved physics allows for use of AIRS observations in the entire 4.3 micron CO2 absorption band in the retrieval of temperature profile T(p) during both day and night. Tropospheric sounding 15 micron CO2 observations are now used primarily in the generation of cloud cleared radiances R(sub i). This approach allows for the generation of accurate values of R(sub i) and T(p) under most cloud conditions. 2) Another very significant improvement in Version 5 is the ability to generate accurate case-by-case, level-by-level error estimates for the atmospheric temperature profile, as well as for channel-by-channel error estimates for R(sub i). These error estimates are used for Quality Control of the retrieved products. We have conducted forecast impact experiments assimilating AIRS temperature profiles with different levels of Quality Control using the NASA GEOS-5 data assimilation system. Assimilation of Quality Controlled T(p) resulted in significantly improved forecast skill compared to that obtained from analyses obtained when all data used operationally by NCEP, except for AIRS data, is assimilated. We also conducted an experiment assimilating AIRS radiances uncontaminated by clouds, as done operationally by ECMWF and NCEP. Forecast resulting from assimilated AIRS radiances were of poorer quality than those obtained assimilating AIRS temperatures.

  13. Data Assimilation Experiments using Quality Controlled AIRS Version 5 Temperature Soundings

    NASA Technical Reports Server (NTRS)

    SUsskind, Joel

    2008-01-01

    The AIRS Science Team Version 5 retrieval algorithm has been finalized and is now operational at the Goddard DAAC in the processing (and reprocessing) of all AIRS data. The AIRS Science Team Version 5 retrieval algorithm contains two significant improvements over Version 4: 1) Improved physics allows for use of AIRS observations in the entire 4.3 pm C02 absorption band in the retrieval of temperature profile T(p) during both day and night. Tropospheric sounding 15 pm C02 observations are now used primarily in the generation of cloud cleared radiances Ri. This approach allows for the generation of accurate values of Ri and T(p) under most cloud conditions. 2) Another very significant improvement in Version 5 is the ability to generate accurate case-by-case, level-by-level error estimates for the atmospheric temperature profile, as well as for channel-by- channel error estimates for Ri. These error estimates are used for quality control of the retrieved products. We have conducted forecast impact experiments assimilating AIRS temperature profiles with different levels of quality control using the NASA GEOS-5 data assimilation system. Assimilation of quality controlled T(p) resulted in significantly improved forecast skill compared to that obtained from analyses obtained when all data used operationally by NCEP, except for AIRS data, is assimilated. We also conducted an experiment assimilating AIRS radiances uncontaminated by clouds, as done Operationally by ECMWF and NCEP. Forecasts resulting from assimilated AIRS radiances were of poorer quality than those obtained assimilating AIRS temperatures.

  14. Stimulation of bioluminescence in Noctiluca sp. using controlled temperature changes.

    PubMed

    Han, Jing; Li, GuiJuan; Liu, HuanYing; Hu, HaoHao; Zhang, XueGang

    2013-01-01

    Bioluminescence induced by multifarious stimuli has long been observed and is remains under investigation because of its great complexity. In particular, the exact mechanism underlying bioluminescence is not yet fully understood. This work presents a new experimental method for studying Noctiluca sp. bioluminescence under temperature change stimulation. It is a study of Noctiluca sp. bioluminescence using controlled temperature changes in a tank. A characteristic of this experiment is the large volume of water used (1 m(3) in a tank of 2 × 1 × 1 m). Temperature changes were controlled by two methods. In the first, a flask filled with hot water was introduced into the tank and in the second, a water heater was used in the tank. Temperature changes were recorded using sensors. Noctiluca sp. bioluminescence was recorded using a Canon 5D Mark II and this allowed the characteristics of Noctiluca sp. bioluminescence under temperature change stimulation to be monitored.

  15. Temperature Measurement and Control System for Transtibial Prostheses: Functional Evaluation.

    PubMed

    Ghoseiri, Kamiar; Zheng, Yong Ping; Leung, Aaron K L; Rahgozar, Mehdi; Aminian, Gholamreza; Lee, Tat Hing; Safari, Mohammad Reza

    2016-10-03

    The accumulation of heat inside the prosthetic socket increases skin temperature and fosters perspiration, which consequently leads to high tissue stress, friction blister, discomfort, unpleasant odor, and decreased prosthesis suspension and use. In the present study, the prototype of a temperature measurement and control (TM&C) system was designed, fabricated, and functionally evaluated in a phantom model of the transtibial prosthetic socket. The TM&C system was comprised of 12 thermistors divided equally into two groups that arranged internal and external to a prosthetic silicone liner. Its control system was programmed to select the required heating or cooling function of a thermal pump to provide thermal equilibrium based on the amount of temperature difference from a defined set temperature, or the amount of difference between the mean temperature recorded by inside and outside thermistors. A thin layer of aluminum was used for thermal conduction between the thermal pump and different sites around the silicone liner. The results showed functionality of the TM&C system for thermoregulation inside the prosthetic socket. However, enhancing the structure of this TM&C system, increasing its thermal power, and decreasing its weight and cost are main priorities before further development.

  16. Fermilab linac upgrade side coupled cavity temperature control system

    SciTech Connect

    Crisp, J.; Satti, J.

    1991-05-01

    Each cavity section has a temperature control system which maintains the resonant frequency by exploiting the 17.8 ppm/{degree}C frequency sensitivity of the copper cavities. Each accelerating cell has a cooling tube brazed azimuthally to the outside surface. Alternate supply and return connection to the water manifolds reduce temperature gradients and maintain physical alignment of the cavity string. Special tubing with spiral inner fins and large flow rate are used to reduce the film coefficient. Temperature is controlled by mixing chilled water with the water circulating between the cavity and the cooling skid located outside the radiation enclosure. Chilled water flow is regulated with a valve controlled by a local microcomputer. The temperature loop set point will be obtained from a slower loop which corrects the phase error between the cavity section and the rf drive during normal beam loaded conditions. Time constants associated with thermal gradients induced in the cavity with the rf power require programming it to the nominal 7.1 MW level over a 1 minute interval to limit the reverse power. 4 refs., 4 figs.

  17. Optoacoustic temperature determination and automatic coagulation control in rabbits

    NASA Astrophysics Data System (ADS)

    Schlott, Kerstin; Koinzer, Stefan; Ptaszynski, Lars; Luft, Susanne; Baade, Alex; Bever, Marco; Roider, Johann; Birngruber, Reginald; Brinkmann, Ralf

    2011-03-01

    Retinal laser photocoagulation is an established treatment method for many retinal diseases like macula edema or diabetic retinopathy. The selection of the laser parameters is so far based on post treatment evaluation of the lesion size and strength. Due to local pigment variations in the fundus and individual transmission the same laser parameters often lead to an overtreatment. Optoacoustic allows a non invasive monitoring of the retinal temperature increase during retinal laser irradiation by measuring the temperature dependent pressure amplitudes, which are induced by short probe laser pulses. A 75 ns/ 523 nm Nd:YLF was used as a probe laser at a repetition rate of 1 kHz, and a cw / 532 nm treatment laser for heating. A contact lens was modified with a ring-shaped ultrasonic transducer to detect the pressure waves at the cornea. Temperatures were collected for irradiations leading to soft or invisible lesions. Based on this data the threshold for denaturation was found. By analyzing the initial temperature increase, the further temperature development during irradiation could be predicted. An algorithm was found to calculate the irradiation time, which is needed for a soft lesion formation, from the temperature curve. By this it was possible to provide a real-time dosimetry by automatically switching off the treatment laser after the calculated irradiation time. Automatically controlled coagulations appear softer and more uniformly.

  18. Lesion strength control by automatic temperature guided retinal photocoagulation

    NASA Astrophysics Data System (ADS)

    Schlott, Kerstin; Koinzer, Stefan; Baade, Alexander; Birngruber, Reginald; Roider, Johann; Brinkmann, Ralf

    2016-09-01

    Laser photocoagulation is an established treatment for a variety of retinal diseases. However, when using the same irradiation parameter, the size and strength of the lesions are unpredictable due to unknown inter- and intraindividual optical properties of the fundus layers. The aim of this work is to investigate a feedback system to generate desired lesions of preselectable strengths by automatically controlling the irradiation time. Optoacoustics were used for retinal temperature monitoring. A 532-nm continuous wave Nd:YAG laser was used for photocoagulation. A 75-ns/523-nm Q-switched Nd:YLF laser simultaneously excited temperature-dependent pressure transients, which were detected at the cornea by an ultrasonic transducer embedded in a contact lens. The temperature data were analyzed during the irradiation by a LabVIEW routine. The treatment laser was switched off automatically when the required lesion strength was achieved. Five different feedback control algorithms for different lesion sizes were developed and tested on rabbits in vivo. With a laser spot diameter of 133 μm, five different lesion types with ophthalmoscopically visible diameters ranging mostly between 100 and 200 μm, and different appearances were achieved by automatic exposure time control. The automatically controlled lesions were widely independent of the treatment laser power and the retinal pigmentation.

  19. Proppant-flowback control in high-temperature wells

    SciTech Connect

    1998-06-01

    Proppant flowback following fracturing treatments can be controlled by use of resin-coated proppant, inorganic fibers, or polymer strips. Each of these technologies has limitations. Resin-coated proppants cannot be used above 374 F and require an activator below 158 F. Thermoplastic strips cannot be used at temperatures above their melting point. Glass fibers have been used successfully for proppant-flowback control, but they cannot be used at reservoir temperatures below 302 F, they provide only short-term control in carbonate reservoirs, and they cannot be used in an environment where they would be exposed to HF. A new high-performance fiber for proppant-flow-back control has been developed to overcome these limitations. In laboratory testing, these fibers were resistant to steam, diesel, xylene, HCl, and mud acid at temperatures up to 482 F for periods up to 7 months. Field testing in deep, hot, carbonate reservoirs confirmed the performance of the new fiber. Case histories of gas wells are given.

  20. Configurational temperature control for atomic and molecular systems.

    PubMed

    Travis, Karl P; Braga, Carlos

    2008-01-07

    A new configurational temperature thermostat suitable for molecules with holonomic constraints is derived. This thermostat has a simple set of motion equations, can generate the canonical ensemble in both position and momentum space, acts homogeneously through the spatial coordinates, and does not intrinsically violate the constraints. Our new configurational thermostat is closely related to the kinetic temperature Nosé-Hoover thermostat with feedback coupled to the position variables via a term proportional to the net molecular force. We validate the thermostat by comparing equilibrium static and dynamic quantities for a fluid of n-decane molecules under configurational and kinetic temperature control. Practical aspects concerning the implementation of the new thermostat in a MOLECULAR DYNAMICS code and the potential applications are discussed.

  1. Parallel circuits control temperature preference in Drosophila during ageing.

    PubMed

    Shih, Hsiang-Wen; Wu, Chia-Lin; Chang, Sue-Wei; Liu, Tsung-Ho; Lai, Jason Sih-Yu; Fu, Tsai-Feng; Fu, Chien-Chung; Chiang, Ann-Shyn

    2015-07-16

    The detection of environmental temperature and regulation of body temperature are integral determinants of behaviour for all animals. These functions become less efficient in aged animals, particularly during exposure to cold environments, yet the cellular and molecular mechanisms are not well understood. Here, we identify an age-related change in the temperature preference of adult fruit flies that results from a shift in the relative contributions of two parallel mushroom body (MB) circuits—the β'- and β-systems. The β'-circuit primarily controls cold avoidance through dopamine signalling in young flies, whereas the β-circuit increasingly contributes to cold avoidance as adult flies age. Elevating dopamine levels in β'-afferent neurons of aged flies restores cold sensitivity, suggesting that the alteration of cold avoidance behaviour with ageing is functionally reversible. These results provide a framework for investigating how molecules and individual neural circuits modulate homeostatic alterations during the course of senescence.

  2. Low-temperature thermal control for a lunar base

    NASA Technical Reports Server (NTRS)

    Swanson, Theodore D.; Radermacher, Reinhard; Costello, Frederick A.; Moore, James S., Jr.; Mengers, David R.

    1990-01-01

    The generic problem of rejecting low- to moderate-temperature heat from space facilities located in a hot thermal sink environment is studied, and the example of a lunar base located near the equator is described. The effective thermal sink temperature is often above or near nominal room temperature. A three heat pump assisted thermal bus concept appears to be the most viable as they are the least sensitive to environmental conditions. Weight estimates are also developed for each of the five thermal control concepts studied: (1) 149kg/kW for a central thermal loop with unitary heat pumps; (2) 133 kg/kW for a conventional bus connected to large, central heat pumps at the radiator; (3) 134 kg/kW for a central, dual loop heat pump concept; (4) 95 kg/kW for the selective field-of-view radiator; and (5) 126 kg/kW for the regolith concept.

  3. Controlled Chemistry Helium High Temperature Materials Test Loop

    SciTech Connect

    Richard N. WRight

    2005-08-01

    A system to test aging and environmental effects in flowing helium with impurity content representative of the Next Generation Nuclear Plant (NGNP) has been designed and assembled. The system will be used to expose microstructure analysis coupons and mechanical test specimens for up to 5,000 hours in helium containing potentially oxidizing or carburizing impurities controlled to parts per million levels. Impurity levels in the flowing helium are controlled through a feedback mechanism based on gas chromatography measurements of the gas chemistry at the inlet and exit from a high temperature retort containing the test materials. Initial testing will focus on determining the nature and extent of combined aging and environmental effects on microstructure and elevated temperature mechanical properties of alloys proposed for structural applications in the NGNP, including Inconel 617 and Haynes 230.

  4. Northwestern Pacific typhoon intensity controlled by changes in ocean temperatures

    PubMed Central

    Mei, Wei; Xie, Shang-Ping; Primeau, François; McWilliams, James C.; Pasquero, Claudia

    2015-01-01

    Dominant climatic factors controlling the lifetime peak intensity of typhoons are determined from six decades of Pacific typhoon data. We find that upper ocean temperatures in the low-latitude northwestern Pacific (LLNWP) and sea surface temperatures in the central equatorial Pacific control the seasonal average lifetime peak intensity by setting the rate and duration of typhoon intensification, respectively. An anomalously strong LLNWP upper ocean warming has favored increased intensification rates and led to unprecedentedly high average typhoon intensity during the recent global warming hiatus period, despite a reduction in intensification duration tied to the central equatorial Pacific surface cooling. Continued LLNWP upper ocean warming as predicted under a moderate [that is, Representative Concentration Pathway (RCP) 4.5] climate change scenario is expected to further increase the average typhoon intensity by an additional 14% by 2100. PMID:26601179

  5. Northwestern Pacific typhoon intensity controlled by changes in ocean temperatures.

    PubMed

    Mei, Wei; Xie, Shang-Ping; Primeau, François; McWilliams, James C; Pasquero, Claudia

    2015-05-01

    Dominant climatic factors controlling the lifetime peak intensity of typhoons are determined from six decades of Pacific typhoon data. We find that upper ocean temperatures in the low-latitude northwestern Pacific (LLNWP) and sea surface temperatures in the central equatorial Pacific control the seasonal average lifetime peak intensity by setting the rate and duration of typhoon intensification, respectively. An anomalously strong LLNWP upper ocean warming has favored increased intensification rates and led to unprecedentedly high average typhoon intensity during the recent global warming hiatus period, despite a reduction in intensification duration tied to the central equatorial Pacific surface cooling. Continued LLNWP upper ocean warming as predicted under a moderate [that is, Representative Concentration Pathway (RCP) 4.5] climate change scenario is expected to further increase the average typhoon intensity by an additional 14% by 2100.

  6. ACTH and. cap alpha. -melanotropin in central temperature control

    SciTech Connect

    Lipton, J.M.; Glyn, J.R.; Zimmer, J.A.

    1981-11-01

    Adrenocorticotropin (ACTH) and ..cap alpha..-melanotropin (..cap alpha..-MSH) occur in brain tissue known to be important to temperature control. These peptides cause hypothermia if they are injected centrally in sufficient doses, but they do not act on the central set point of temperature control. Instead they appear to inhibit central pathways for heat conservation and production. In addition to their hypothermic capability, these peptides are antipyretic when given centrally in doses that have no effect on normal body temperature. ACTH has previously been associated with fever reduction in both clinical and experimental studies, and it may be that endogenous central ACTH is important for limitation of maximal fever. The hypothermic and antipyretic effects of ACTH do not depend on stimulation of the adrenal cortex because they are also observed in adrenalectomized rabbits. Nor is the antipyretic effect limited to the rabbit inasmuch as a comparable effect has been demonstrated in the squirrel monkey. The two peptides may be involved in central mediation of normal thermoregulation and fever, perhaps limiting the febrile response and other rises in body temperature by acting as neurotransmitters or neuromodulators in central thermoregulatory pathways.

  7. An Acoustothermal Microheater with Omni-temperature Controllability

    NASA Astrophysics Data System (ADS)

    Ha, Byung Hang; Lee, Kang Soo; Destgeer, Ghulam; Park, Jinsoo; Jung, Jin Ho; Sung, Hyung Jin

    Here we report the first observation of rapid volumetric heating of polydimethylsiloxane (PDMS) under cyclic loadings at a range of high (∼MHz) frequencies. Based on the finding, we developed a microheater which utilizes the vibration damping of PDMS, the most commonly used material in microfluidics, induced by sound waves generated and precisely controlled by a surface acoustic wave (SAW) microfluidic system. An omni-temperature controllability of the microheater enabled us to perform two-step continuous flow polymerase chain reaction for a billion-fold amplification of 134 bp DNA amplicon in less than 45 sec.

  8. Chemical control of rate and onset temperature of nadimide polymerization

    NASA Technical Reports Server (NTRS)

    Lauver, R. W.

    1985-01-01

    The chemistry of norbornenyl capped imide compounds (nadimides) is briefly reviewed with emphasis on the contribution of Diels-Alder reversion in controlling the rate and onset of the thermal polymerization reaction. Control of onset temperature of the cure exotherm by adjusting the concentration of maleimide is demonstrated using selected model compounds. The effects of nitrophenyl compounds as free radical retarders on nadimide reactivity are discussed. A simple copolymerization model is proposed for the overall nadimide cure reaction. An approximate numerical analysis is carried out to demonstrate the ability of the model to simulate the trends observed for both maleimide and nitrophenyl additions.

  9. Field Test of Boiler Primary Loop Temperature Controller

    SciTech Connect

    Glanville, P.; Rowley, P.; Schroeder, D.; Brand, L.

    2014-09-01

    Beyond these initial system efficiency upgrades are an emerging class of Advanced Load Monitoring (ALM) aftermarket controllers that dynamically respond to the boiler load, with claims of 10% to 30% of fuel savings over a heating season. For hydronic boilers specifically, these devices perform load monitoring, with continuous measurement of supply and in some cases return water temperatures. Energy savings from these ALM controllers are derived from dynamic management of the boiler differential, where a microprocessor with memory of past boiler cycles prevents the boiler from firing for a period of time, to limit cycling losses and inefficient operation during perceived low load conditions. These differ from OTR controllers, which vary boiler setpoint temperatures with ambient conditions while maintaining a fixed differential. PARR installed and monitored the performance of one type of ALM controller, the M2G from Greffen Systems, at multifamily sites in the city of Chicago and its suburb Cary, IL, both with existing OTR control. Results show that energy savings depend on the degree to which boilers are over-sized for their load, represented by cycling rates. Also savings vary over the heating season with cycling rates, with greater savings observed in shoulder months. Over the monitoring period, over-sized boilers at one site showed reductions in cycling and energy consumption in line with prior laboratory studies, while less over-sized boilers at another site showed muted savings.

  10. Control system for Fermilab`s low temperature upgrade

    SciTech Connect

    Norris, B.L.

    1996-09-01

    Fermilab recently upgraded the Tevatron Cryogenic Systems to allow for lower temperature operation. This Lower Temperature Upgrade grew out of a desire to increase the Colliding Beam Physics energy from 900 GeV to 1000 GeV. A key element in achieving this goal is the new cryogenic control system designed at Fermilab and installed in 24 satellite refrigerators and 8 compressor buildings. The cryogenic improvements and addition hardware like cold compressors exceeded the capability of the original distributed controls package. The new distributed controls package uses a Multibus II platform and Intel`s 80386 microprocessor. Token Ring is used as the link to the systems 6 primary crate locations with Arcnet used as the connection to the systems numerous I/O crates. I/0 capabilities are double the capabilities of the original system. Software has also been upgraded with the introduction of more flexible control loop strategies and Finite State Machines used for automatic sequential control, like quench recovery or cold compressor pump down.

  11. Remote control of magnetostriction-based nanocontacts at room temperature.

    PubMed

    Jammalamadaka, S Narayana; Kuntz, Sebastian; Berg, Oliver; Kittler, Wolfram; Kannan, U Mohanan; Chelvane, J Arout; Sürgers, Christoph

    2015-09-01

    The remote control of the electrical conductance through nanosized junctions at room temperature will play an important role in future nano-electromechanical systems and electronic devices. This can be achieved by exploiting the magnetostriction effects of ferromagnetic materials. Here we report on the electrical conductance of magnetic nanocontacts obtained from wires of the giant magnetostrictive compound Tb0.3Dy0.7Fe1.95 as an active element in a mechanically controlled break-junction device. The nanocontacts are reproducibly switched at room temperature between "open" (zero conductance) and "closed" (nonzero conductance) states by variation of a magnetic field applied perpendicularly to the long wire axis. Conductance measurements in a magnetic field oriented parallel to the long wire axis exhibit a different behaviour where the conductance switches between both states only in a limited field range close to the coercive field. Investigating the conductance in the regime of electron tunneling by mechanical or magnetostrictive control of the electrode separation enables an estimation of the magnetostriction. The present results pave the way to utilize the material in devices based on nano-electromechanical systems operating at room temperature.

  12. Remote control of magnetostriction-based nanocontacts at room temperature

    PubMed Central

    Jammalamadaka, S. Narayana; Kuntz, Sebastian; Berg, Oliver; Kittler, Wolfram; Kannan, U. Mohanan; Chelvane, J. Arout; Sürgers, Christoph

    2015-01-01

    The remote control of the electrical conductance through nanosized junctions at room temperature will play an important role in future nano-electromechanical systems and electronic devices. This can be achieved by exploiting the magnetostriction effects of ferromagnetic materials. Here we report on the electrical conductance of magnetic nanocontacts obtained from wires of the giant magnetostrictive compound Tb0.3Dy0.7Fe1.95 as an active element in a mechanically controlled break-junction device. The nanocontacts are reproducibly switched at room temperature between “open” (zero conductance) and “closed” (nonzero conductance) states by variation of a magnetic field applied perpendicularly to the long wire axis. Conductance measurements in a magnetic field oriented parallel to the long wire axis exhibit a different behaviour where the conductance switches between both states only in a limited field range close to the coercive field. Investigating the conductance in the regime of electron tunneling by mechanical or magnetostrictive control of the electrode separation enables an estimation of the magnetostriction. The present results pave the way to utilize the material in devices based on nano-electromechanical systems operating at room temperature. PMID:26323326

  13. Temperature-gated thermal rectifier for active heat flow control.

    PubMed

    Zhu, Jia; Hippalgaonkar, Kedar; Shen, Sheng; Wang, Kevin; Abate, Yohannes; Lee, Sangwook; Wu, Junqiao; Yin, Xiaobo; Majumdar, Arun; Zhang, Xiang

    2014-08-13

    Active heat flow control is essential for broad applications of heating, cooling, and energy conversion. Like electronic devices developed for the control of electric power, it is very desirable to develop advanced all-thermal solid-state devices that actively control heat flow without consuming other forms of energy. Here we demonstrate temperature-gated thermal rectification using vanadium dioxide beams in which the environmental temperature actively modulates asymmetric heat flow. In this three terminal device, there are two switchable states, which can be regulated by global heating. In the "Rectifier" state, we observe up to 28% thermal rectification. In the "Resistor" state, the thermal rectification is significantly suppressed (<1%). To the best of our knowledge, this is the first demonstration of solid-state active-thermal devices with a large rectification in the Rectifier state. This temperature-gated rectifier can have substantial implications ranging from autonomous thermal management of heating and cooling systems to efficient thermal energy conversion and storage.

  14. A Precise Temperature-Responsive Bistable Switch Controlling Yersinia Virulence

    PubMed Central

    Klein, Johannes; Bücker, René; Herbst, Katharina; Heroven, Ann Kathrin; Pisano, Fabio; Wittmann, Christoph; Münch, Richard; Müller, Johannes; Jahn, Dieter

    2016-01-01

    Different biomolecules have been identified in bacterial pathogens that sense changes in temperature and trigger expression of virulence programs upon host entry. However, the dynamics and quantitative outcome of this response in individual cells of a population, and how this influences pathogenicity are unknown. Here, we address these questions using a thermosensing virulence regulator of an intestinal pathogen (RovA of Yersinia pseudotuberculosis) as a model. We reveal that this regulator is part of a novel thermoresponsive bistable switch, which leads to high- and low-invasive subpopulations within a narrow temperature range. The temperature range in which bistability is observed is defined by the degradation and synthesis rate of the regulator, and is further adjustable via a nutrient-responsive regulator. The thermoresponsive switch is also characterized by a hysteretic behavior in which activation and deactivation occurred on vastly different time scales. Mathematical modeling accurately mirrored the experimental behavior and predicted that the thermoresponsiveness of this sophisticated bistable switch is mainly determined by the thermo-triggered increase of RovA proteolysis. We further observed RovA ON and OFF subpopulations of Y. pseudotuberculosis in the Peyer’s patches and caecum of infected mice, and that changes in the RovA ON/OFF cell ratio reduce tissue colonization and overall virulence. This points to a bet-hedging strategy in which the thermoresponsive bistable switch plays a key role in adapting the bacteria to the fluctuating conditions encountered as they pass through the host’s intestinal epithelium and suggests novel strategies for the development of antimicrobial therapies. PMID:28006011

  15. Injection molding simulation with variothermal mold temperature control of highly filled polyphenylene sulfide

    NASA Astrophysics Data System (ADS)

    Birkholz, A.; Tschiersky, M.; Wortberg, J.

    2015-05-01

    For the installation of a fuel cell stack to convert chemical energy into electricity it is common to apply bipolar plates to separate and distribute reaction gases and cooling agents. For reducing manufacturing costs of bipolar plates a fully automated injection molding process is examined. The high performance thermoplastic matrix material, polyphenylene sulfide (PPS), defies against the chemical setting and the operation temperature up to 200 °C. To adjust also high electrical and thermal conductivity, PPS is highly filled with various carbon fillers up to an amount of 65 percentage by volume. In the first step two different structural plates (one-sided) with three different gate heights and molds are designed according to the characteristics of a bipolar plate. To cope with the approach that this plate should be producible on standard injection molding machines with variothermal mold temperature control, injection molding simulation is used. Additionally, the simulation should allow to formulate a quality prediction model, which is transferrable to bipolar plates. Obviously, the basis for a precise simulation output is an accurate description of the material properties and behavior of the highly filled compound. This, the design of the structural plate and mold and the optimization via simulation is presented, as well. The influence of the injection molding process parameters, e.g. injection time, cycle times, packing pressure, mold temperature, and melt temperature on the form filling have been simulated to determine optimal process conditions. With the aid of the simulation and the variothermal mold temperature control it was possible to reduce the required melt temperature below the decomposition temperature of PPS. Thereby, hazardous decomposition products as hydrogen sulfide are obviated. Thus, the health of the processor, the longevity of the injection molding machine as well as the material and product properties can be protected.

  16. A new expression of Ns versus Ef to an accurate control charge model for AlGaAs/GaAs

    NASA Astrophysics Data System (ADS)

    Bouneb, I.; Kerrour, F.

    2016-03-01

    Semi-conductor components become the privileged support of information and communication, particularly appreciation to the development of the internet. Today, MOS transistors on silicon dominate largely the semi-conductors market, however the diminution of transistors grid length is not enough to enhance the performances and respect Moore law. Particularly, for broadband telecommunications systems, where faster components are required. For this reason, alternative structures proposed like hetero structures IV-IV or III-V [1] have been.The most effective components in this area (High Electron Mobility Transistor: HEMT) on IIIV substrate. This work investigates an approach for contributing to the development of a numerical model based on physical and numerical modelling of the potential at heterostructure in AlGaAs/GaAs interface. We have developed calculation using projective methods allowed the Hamiltonian integration using Green functions in Schrodinger equation, for a rigorous resolution “self coherent” with Poisson equation. A simple analytical approach for charge-control in quantum well region of an AlGaAs/GaAs HEMT structure was presented. A charge-control equation, accounting for a variable average distance of the 2-DEG from the interface was introduced. Our approach which have aim to obtain ns-Vg characteristics is mainly based on: A new linear expression of Fermi-level variation with two-dimensional electron gas density in high electron mobility and also is mainly based on the notion of effective doping and a new expression of AEc

  17. In Situ Microstructural Control and Mechanical Testing Inside the Transmission Electron Microscope at Elevated Temperatures

    NASA Astrophysics Data System (ADS)

    Wang, Baoming; Haque, M. A.

    2015-08-01

    With atomic-scale imaging and analytical capabilities such as electron diffraction and energy-loss spectroscopy, the transmission electron microscope has allowed access to the internal microstructure of materials like no other microscopy. It has been mostly a passive or post-mortem analysis tool, but that trend is changing with in situ straining, heating and electrical biasing. In this study, we design and demonstrate a multi-functional microchip that integrates actuators, sensors, heaters and electrodes with freestanding electron transparent specimens. In addition to mechanical testing at elevated temperatures, the chip can actively control microstructures (grain growth and phase change) of the specimen material. Using nano-crystalline aluminum, nickel and zirconium as specimen materials, we demonstrate these novel capabilities inside the microscope. Our approach of active microstructural control and quantitative testing with real-time visualization can influence mechanistic modeling by providing direct and accurate evidence of the fundamental mechanisms behind materials behavior.

  18. Cascade control of superheated steam temperature with neuro-PID controller.

    PubMed

    Zhang, Jianhua; Zhang, Fenfang; Ren, Mifeng; Hou, Guolian; Fang, Fang

    2012-11-01

    In this paper, an improved cascade control methodology for superheated processes is developed, in which the primary PID controller is implemented by neural networks trained by minimizing error entropy criterion. The entropy of the tracking error can be estimated recursively by utilizing receding horizon window technique. The measurable disturbances in superheated processes are input to the neuro-PID controller besides the sequences of tracking error in outer loop control system, hence, feedback control is combined with feedforward control in the proposed neuro-PID controller. The convergent condition of the neural networks is analyzed. The implementation procedures of the proposed cascade control approach are summarized. Compared with the neuro-PID controller using minimizing squared error criterion, the proposed neuro-PID controller using minimizing error entropy criterion may decrease fluctuations of the superheated steam temperature. A simulation example shows the advantages of the proposed method.

  19. Probing DNA helicase kinetics with temperature-controlled magnetic tweezers.

    PubMed

    Gollnick, Benjamin; Carrasco, Carolina; Zuttion, Francesca; Gilhooly, Neville S; Dillingham, Mark S; Moreno-Herrero, Fernando

    2015-03-18

    Motor protein functions like adenosine triphosphate (ATP) hydrolysis or translocation along molecular substrates take place at nanometric scales and consequently depend on the amount of available thermal energy. The associated rates can hence be investigated by actively varying the temperature conditions. In this article, a thermally controlled magnetic tweezers (MT) system for single-molecule experiments at up to 40 °C is presented. Its compact thermostat module yields a precision of 0.1 °C and can in principle be tailored to any other surface-coupled microscopy technique, such as tethered particle motion (TPM), nanopore-based sensing of biomolecules, or super-resolution fluorescence imaging. The instrument is used to examine the temperature dependence of translocation along double-stranded (ds)DNA by individual copies of the protein complex AddAB, a helicase-nuclease motor involved in dsDNA break repair. Despite moderately lower mean velocities measured at sub-saturating ATP concentrations, almost identical estimates of the enzymatic reaction barrier (around 21-24 k(B)T) are obtained by comparing results from MT and stopped-flow bulk assays. Single-molecule rates approach ensemble values at optimized chemical energy conditions near the motor, which can withstand opposing loads of up to 14 piconewtons (pN). Having proven its reliability, the temperature-controlled MT described herein will eventually represent a routinely applied method within the toolbox for nano-biotechnology.

  20. Temperature controlled material irradiation in the advanced test reactor

    NASA Astrophysics Data System (ADS)

    Ingram, F. W.; Palmer, A. J.; Stites, D. J.

    1998-10-01

    The United States Department of Energy (US DOE) has initiated the development of an Irradiation Test Vehicle (ITV) for fusion materials irradiation at the Advanced Test Reactor (ATR) in Idaho Falls, Idaho, USA. The ITV is capable of providing neutron spectral tailoring and individual temperature control for up to 15 experiment capsules simultaneously. The test vehicle consists of three In-Pile Tubes (IPTs) running the length of the reactor vessel. These IPTs are kept dry and test trains with integral instrumentation are inserted and removed through a transfer shield plate above the reactor vessel head. The test vehicle is designed to irradiate specimens as large as 2.2 cm in diameter, at temperatures of 250-800°C, achieving neutron damage rates as high as 10 displacements per atom per year. The high fast to thermal neutron flux ratio required for fusion materials testing is accomplished by using an aluminum filler to displace as much water as possible from the flux trap and surrounding the filler piece with a ring of replaceable neutron absorbing material. The gas blend temperature control system remains in place from test to test, thus hardware costs for new tests are limited to the experiment capsule train and integral instrumentation.

  1. Robust isothermal electric control of exchange bias at room temperature

    NASA Astrophysics Data System (ADS)

    Binek, Christian

    2011-03-01

    Voltage-controlled spintronics is of particular importance to continue progress in information technology through reduced power consumption, enhanced processing speed, integration density, and functionality in comparison with present day CMOS electronics. Almost all existing and prototypical solid-state spintronic devices rely on tailored interface magnetism, enabling spin-selective transmission or scattering of electrons. Controlling magnetism at thin-film interfaces, preferably by purely electrical means, is a key challenge to better spintronics. Currently, most attempts to electrically control magnetism focus on potentially large magnetoelectric effects of multiferroics. We report on our interest in magnetoelectric Cr 2 O3 (chromia). Robust isothermal electric control of exchange bias is achieved at room temperature in perpendicular anisotropic Cr 2 O3 (0001)/CoPd exchange bias heterostructures. This discovery promises significant implications for potential spintronics. From the perspective of basic science, our finding serves as macroscopic evidence for roughness-insensitive and electrically controllable equilibrium boundary magnetization in magnetoelectric antiferromagnets. The latter evolves at chromia (0001) surfaces and interfaces when chromia is in one of its two degenerate antiferromagnetic single domain states selected via magnetoelectric annealing. Theoretical insight into the boundary magnetization and its role in electrically controlled exchange bias is gained from first-principles calculations and general symmetry arguments. Measurements of spin-resolved ultraviolet photoemission, magnetometry at Cr 2 O3 (0001) surfaces, and detailed investigations of the unique exchange bias properties of Cr 2 O3 (0001)/CoPd including its electric controllability provide macroscopically averaged information about the boundary magnetization of chromia. Laterally resolved X-ray PEEM and temperature dependent MFM reveal detailed microscopic information of the chromia

  2. Accurate Control of 17β-Estradiol Long-Term Release Increases Reliability and Reproducibility of Preclinical Animal Studies.

    PubMed

    Gérard, Céline; Gallez, Anne; Dubois, Charline; Drion, Pierre; Delahaut, Philippe; Quertemont, Etienne; Noël, Agnès; Pequeux, Christel

    2017-03-01

    Estrogens are the subject of intensive researches aiming to elucidate their mechanism of action on the various tissues they target and especially on mammary gland and breast cancer. The use of ready-to-use slow releasing devices to administer steroids, especially estrogens, to small experimental animals remains the method of choice in terms of animal well-being and of safety for both the researcher and the animal. In this study, we evaluated and compared, in vitro and in vivo, the release kinetic of estradiol (E2) over sixty days from two different slow-releasing systems: the matrix pellet (MP) and the reservoir implant (RI). We compared the impact of these systems in three E2-sensitive mouse models : mammary gland development, human MCF7 adenocarcinoma xenograft and mouse melanoma progression. The real amount of E2 that is released from both types of devices could differ from manufacturer specifications due to inadequate release for MP and initial burst effect for RI. Compared to MP, the interindividual variability was reduced with RI thanks to a superior control of the E2 release. Depending on the dose-dependent sensitivity of the physiological or pathological readout studied, this could lead to an improvement of the statistical power of in vivo experiments and thus to a reduction of the required animal number. Altogether, our data draw attention on the importance to adequately select the slow-releasing device that is the most appropriated to a specific experiment to better fulfill the 3Rs rule (Replacement, Reduction, Refinement) related to animal welfare and protection.

  3. MEMS Device Being Developed for Active Cooling and Temperature Control

    NASA Technical Reports Server (NTRS)

    Moran, Matthew E.

    2001-01-01

    High-capacity cooling options remain limited for many small-scale applications such as microelectronic components, miniature sensors, and microsystems. A microelectromechanical system (MEMS) is currently under development at the NASA Glenn Research Center to meet this need. It uses a thermodynamic cycle to provide cooling or heating directly to a thermally loaded surface. The device can be used strictly in the cooling mode, or it can be switched between cooling and heating modes in milliseconds for precise temperature control. Fabrication and assembly are accomplished by wet etching and wafer bonding techniques routinely used in the semiconductor processing industry. Benefits of the MEMS cooler include scalability to fractions of a millimeter, modularity for increased capacity and staging to low temperatures, simple interfaces and limited failure modes, and minimal induced vibration.

  4. Temperature controlled material irradiation in the advanced test reactor

    SciTech Connect

    Furstenau, R.V.; Ingrahm, F.W.

    1995-12-31

    The Advanced Test Reactor (ATR) is located at the Idaho National Engineering Laboratory (INEL) near Idaho Falls, Idaho, USA and is owned and regulated by the U.S. Department of Energy (US DOE). The ATR is operated for the US DOE by Lockheed Martin Idaho Technologies. In recent years, prime irradiation space in the ATR has been made available for use by customers having irradiation service needs in addition to the reactor`s principal user, the U.S. Naval Nuclear Propulsion Program. To enhance the reactor`s capabilities, the US DOE has initiated the development of an Irradiation Test Vehicle (ITV) capable of providing neutron spectral tailoring and temperature control for up to 28 experiments. The ATR-ITV will have the flexibility to simultaneously support a variety of experiments requiring fast, thermal or mixed spectrum neutron environments. Temperature control is accomplished by varying the thermal conductivity across a gas gap established between the experiment specimen capsule wall and the experiment `in-pile tube (IPT)` inside diameter. Thermal conductivity is adjusted by alternating the control gas mixture ratio of two gases with different thermal conductivities.

  5. Methane reforming in a temperature-controlled DBD reactor

    NASA Astrophysics Data System (ADS)

    Levko, Dmitry; Raja, Laxminarayan

    2015-09-01

    Methane and carbon dioxide are among the main products of human activity. Therefore, they are considered among greenhouse gases, which may cause the global warming. On the other hand, methane is widely used in everyday life as an energy source and in industry for the synthesis of different chemicals. In order to utilize greenhouse gases or to generate chemicals from methane, one needs first to dissociate it. Then, this gas converts into desired products such as methanol, gasoline, syn-gas etc. Nowadays, there are several methods for CH4 conversion. Steam reforming, partial oxidation, thermal and non-thermal plasmas are among them. During the last decades, the use of non-thermal plasma for methane reforming attracts more and more attention. This is caused by the possibility to control the process of methane conversion as well as the gas component content at the reactor outlet. In addition, the use of non-thermal plasma facilitates the control of reactor start up. The goal of the present work is the deep understanding of the plasma chemical processes accompanying the methane-air conversion in a temperature-controlled DBD reactor. To do this, we have developed the kinetic mechanism of CH4/N2/O2 conversion for the gas temperature range 300-800 K and applied it to the global model.

  6. To the problem of electron temperature control in plasma

    SciTech Connect

    Galechyan, G.A.; Anna, P.R.

    1995-12-31

    One of the main problems in low temperature plasma is control plasma parameters at fixed values of current and gas pressure in the discharge. It is known that an increase in the intensity of sound wave directed along the positive column to values in excess of a definite threshold leads to essential rise of the temperature of electrons. However, no less important is the reduction of electron temperature in the discharge down to the value less than that in plasma in the absence external influence. It is known that to reduce the electron temperature in the plasma of CO{sub 2} laser, easily ionizable admixture are usually introduced in the discharge area with the view of increasing the overpopulation. In the present work we shall show that the value of electron temperature can be reduced by varying of sound wave intensity at its lower values. The experiment was performed on an experimental setup consisted of the tube with length 52 cm and diameter 9.8 cm, two electrodes placed at the distance of 27 cm from each other. An electrodynamical radiator of sound wave was fastened to one of tube ends. Fastened to the flange at the opposite end was a microphone for the control of sound wave parameters. The studies were performed in range of pressures from 40 to 180 Torr and discharge currents from 40 to 110 mA. The intensity of sound wave was varied from 74 to 92 dB. The measurement made at the first resonance frequency f = 150 Hz of sound in the discharge tube, at which a quarter of wave length keep within the length of the tube. The measurement of longitudinal electric field voltage in plasma of positive column was conducted with the help of two probes according to the compensation method. Besides, the measurement of gas temperature in the discharge were taken. Two thermocouple sensors were arranged at the distance of 8 cm from the anode, one of them being installed on the discharge tube axis, the second-fixed the tube wall.

  7. Battery charge control with temperature compensated voltage limit

    NASA Technical Reports Server (NTRS)

    Thierfelder, H. E.

    1983-01-01

    Battery charge control for orbiting spacecraft with mission durations from three to ten years, is a critical design feature that is discussed. Starting in 1974, the General Electric Space Systems Division designed, manufactured and tested battery systems for six different space programs. Three of these are geosynchronous missions, two are medium altitude missions and one is a near-earth mission. All six power subsystems contain nickel cadmium batteries which are charged using a temperature compensated voltage limit. This charging method was found to be successful in extending the life of nickel cadmium batteries in all three types of earth orbits. Test data and flight data are presented for each type of orbit.

  8. Transparent electrically conducting thin films for spacecraft temperature control applications

    NASA Technical Reports Server (NTRS)

    Hass, G.; Heaney, J. B.; Toft, A. R.

    1979-01-01

    Thin transparent films of In2O3 or In2O3 + SnO2 prepared by evaporation or sputtering have been tested for use as surface layers for spacecraft temperature control coatings. The films are intended to prevent nonuniform electric charge buildup on the spacecraft exterior. Film thicknesses of 300 to 500 A were found to be optimal in terms of durability and minimum impact on the solar absorptance and the thermal emissivity of the underlayers. As a verification of their suitability for long-duration space missions, the films were subjected to simulated solar UV plus proton irradiation in a vacuum.

  9. Moderate temperature control technology for a lunar base

    NASA Technical Reports Server (NTRS)

    Swanson, Theodore D.; Sridhar, K. R.; Gottmann, Matthias

    1993-01-01

    A parametric analysis is performed to compare different heat pump based thermal control systems for a Lunar Base. Rankine cycle and absorption cycle heat pumps are compared and optimized for a 100 kW cooling load. Variables include the use or lack of an interface heat exchanger, and different operating fluids. Optimization of system mass to radiator rejection temperature is performed. The results indicate a relatively small sensitivity of Rankine cycle system mass to these variables, with optimized system masses of about 6000 kg for the 100 kW thermal load. It is quantitaively demonstrated that absorption based systems are not mass competitive with Rankine systems.

  10. Wall temperature control of low-speed body drag

    NASA Technical Reports Server (NTRS)

    Lin, J. C.; Ash, R. L.

    1986-01-01

    The use of thermal means to control drag under turbulent boundary layer conditions is examined. Numerical calculations are presented for both skin friction and (unseparated) pressure drag for turbulent boundary-layer flows over a fuselage-like body with wall heat transfer. In addition, thermal control of separation on a bluff body is investigated. It is shown that a total drag reduction of up to 20 percent can be achieved for wall heating with a wall-to-total-freestream temperature ratio of 2. For streamlined slender bodies, partial wall heating of the forebody can produce almost the same order of total drag reduction as the full body heating case. For bluff bodies, the separation delay from partial wall cooling of the afterbody is approximately the same as for the fully cooled body.

  11. Robust isothermal electric control of exchange bias at room temperature.

    PubMed

    He, Xi; Wang, Yi; Wu, Ning; Caruso, Anthony N; Vescovo, Elio; Belashchenko, Kirill D; Dowben, Peter A; Binek, Christian

    2010-07-01

    Voltage-controlled spin electronics is crucial for continued progress in information technology. It aims at reduced power consumption, increased integration density and enhanced functionality where non-volatile memory is combined with high-speed logical processing. Promising spintronic device concepts use the electric control of interface and surface magnetization. From the combination of magnetometry, spin-polarized photoemission spectroscopy, symmetry arguments and first-principles calculations, we show that the (0001) surface of magnetoelectric Cr(2)O(3) has a roughness-insensitive, electrically switchable magnetization. Using a ferromagnetic Pd/Co multilayer deposited on the (0001) surface of a Cr(2)O(3) single crystal, we achieve reversible, room-temperature isothermal switching of the exchange-bias field between positive and negative values by reversing the electric field while maintaining a permanent magnetic field. This effect reflects the switching of the bulk antiferromagnetic domain state and the interface magnetization coupled to it. The switchable exchange bias sets in exactly at the bulk Néel temperature.

  12. Robust isothermal electric control of exchange bias at room temperature

    SciTech Connect

    He, X.; Vescovo, E.; Wang, Y.; Caruso, A.N.; Belashchenko, K.D.; Dowben, P.A.; Binek, C.

    2010-06-20

    Voltage-controlled spin electronics is crucial for continued progress in information technology. It aims at reduced power consumption, increased integration density and enhanced functionality where non-volatile memory is combined with high-speed logical processing. Promising spintronic device concepts use the electric control of interface and surface magnetization. From the combination of magnetometry, spin-polarized photoemission spectroscopy, symmetry arguments and first-principles calculations, we show that the (0001) surface of magnetoelectric Cr{sub 2}O{sub 3} has a roughness-insensitive, electrically switchable magnetization. Using a ferromagnetic Pd/Co multilayer deposited on the (0001) surface of a Cr{sub 2}O{sub 3} single crystal, we achieve reversible, room-temperature isothermal switching of the exchange-bias field between positive and negative values by reversing the electric field while maintaining a permanent magnetic field. This effect reflects the switching of the bulk antiferromagnetic domain state and the interface magnetization coupled to it. The switchable exchange bias sets in exactly at the bulk Neel temperature.

  13. Temperature and humidity control system in a lunar base.

    PubMed

    Izutani, N; Kobayashi, N; Ogura, T; Nomura, I; Kawazoe, M; Yamamoto, H

    1992-01-01

    An increasing number of lunar base construction programs are in the process of developing lunar resources such as helium 3. The objective of the present work is to evaluate the temperature and humidity control system, which will allow man to live and work on the moon while developing lunar resources. The results of thermal load calculation show that the load of electric lighting is a 80 to 90% of the cooling load in the habitat module and that only the cooling function is required for temperature control. Due to this, a fluorocarbon refrigerant heat pump system was selected to satisfy reliability, energy consumption, size and weight requirements for the lunar base equipment. According to the load calculation, occupants will feel discomfort due to radiant heat from lighting fixtures. To resolve this problem, an air conditioning system, used in combination with forced convective cooling and panel cooling on the ceiling, was adopted in the living space. Moreover, the experiment on the ground was carried out to evaluate the effects of panel cooling.

  14. Evaluating geothermal and hydrogeologic controls on regional groundwater temperature distribution

    NASA Astrophysics Data System (ADS)

    Burns, Erick R.; Ingebritsen, Steven E.; Manga, Michael; Williams, Colin F.

    2016-02-01

    A one-dimensional (1-D) analytic solution is developed for heat transport through an aquifer system where the vertical temperature profile in the aquifer is nearly uniform. The general anisotropic form of the viscous heat generation term is developed for use in groundwater flow simulations. The 1-D solution is extended to more complex geometries by solving the equation for piece-wise linear or uniform properties and boundary conditions. A moderately complex example, the Eastern Snake River Plain (ESRP), is analyzed to demonstrate the use of the analytic solution for identifying important physical processes. For example, it is shown that viscous heating is variably important and that heat conduction to the land surface is a primary control on the distribution of aquifer and spring temperatures. Use of published values for all aquifer and thermal properties results in a reasonable match between simulated and measured groundwater temperatures over most of the 300 km length of the ESRP, except for geothermal heat flow into the base of the aquifer within 20 km of the Yellowstone hotspot. Previous basal heat flow measurements (˜110 mW/m2) made beneath the ESRP aquifer were collected at distances of >50 km from the Yellowstone Plateau, but a higher basal heat flow of 150 mW/m2 is required to match groundwater temperatures near the Plateau. The ESRP example demonstrates how the new tool can be used during preliminary analysis of a groundwater system, allowing efficient identification of the important physical processes that must be represented during more-complex 2-D and 3-D simulations of combined groundwater and heat flow.

  15. Evaluating geothermal and hydrogeologic controls on regional groundwater temperature distribution

    USGS Publications Warehouse

    Burns, Erick R.; Ingebritsen, Steven E.; Manga, Michael; Williams, Colin F.

    2016-01-01

    A one-dimensional (1-D) analytic solution is developed for heat transport through an aquifer system where the vertical temperature profile in the aquifer is nearly uniform. The general anisotropic form of the viscous heat generation term is developed for use in groundwater flow simulations. The 1-D solution is extended to more complex geometries by solving the equation for piece-wise linear or uniform properties and boundary conditions. A moderately complex example, the Eastern Snake River Plain (ESRP), is analyzed to demonstrate the use of the analytic solution for identifying important physical processes. For example, it is shown that viscous heating is variably important and that heat conduction to the land surface is a primary control on the distribution of aquifer and spring temperatures. Use of published values for all aquifer and thermal properties results in a reasonable match between simulated and measured groundwater temperatures over most of the 300 km length of the ESRP, except for geothermal heat flow into the base of the aquifer within 20 km of the Yellowstone hotspot. Previous basal heat flow measurements (∼110 mW/m2) made beneath the ESRP aquifer were collected at distances of >50 km from the Yellowstone Plateau, but a higher basal heat flow of 150 mW/m2 is required to match groundwater temperatures near the Plateau. The ESRP example demonstrates how the new tool can be used during preliminary analysis of a groundwater system, allowing efficient identification of the important physical processes that must be represented during more-complex 2-D and 3-D simulations of combined groundwater and heat flow.

  16. Temperature control in a solar collector field using Filtered Dynamic Matrix Control.

    PubMed

    Lima, Daniel Martins; Normey-Rico, Julio Elias; Santos, Tito Luís Maia

    2016-05-01

    This paper presents the output temperature control of a solar collector field of a desalinization plant using the Filtered Dynamic Matrix Control (FDMC). The FDMC is a modified controller based on the Dynamic Matrix Control (DMC), a predictive control strategy widely used in industry. In the FDMC, a filter is used in the prediction error, which allows the modification of the robustness and disturbance rejection characteristics of the original algorithm. The implementation and tuning of the FDMC are simple and maintain the advantages of DMC. Several simulation results using a validated model of the solar plant are presented considering different scenarios. The results are also compared to nonlinear control techniques, showing that FDMC, if properly tuned, can yield similar results to more complex control algorithms.

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

    DOEpatents

    Blackburn, Bryan M; Wachsman, Eric D

    2015-05-12

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

  18. Accurate high-pressure and high-temperature effective pair potentials for the systems N2-N and O2-O

    NASA Astrophysics Data System (ADS)

    van Thiel, M.; Ree, F. H.

    1996-04-01

    Statistical mechanical chemical equilibrium calculations of N2 and O2 show that these molecules dissociate behind strong shock waves. Our determination of accurate intermolecular potentials has required the consideration of the dissociation products N and O. Our previous theoretical efforts to predict the thermodynamic properties of these molecules relied in part on corresponding states theory and shock wave data of argon, without consideration of the dissociation products. Recent high-pressure Hugoniot measurements, however, allowed a more accurate determination of the potentials and the explicit inclusion of the dissociation products. The best fit to the data is obtained with the exponential-6 coefficients, for O2-O2: ɛ/k=125 K, r*=3.86 Å, α=13.2; for O-O: ɛ/k=700 K, r*=2.40 Å, α=11.0; for N2-N2: ɛ/k=293 K, r*=3.91 Å, α=11.5; and for N-N: ɛ/k=600 K, r*=2.47 Å, α=10.0. The unlike pair interactions are obtained from these like interactions with a modified Lorentz-Berthelot rule. The coefficients in the modified Lorentz-Berthelot equations are k/l/m=1/1/0.93 for O2-O- and k/l/m=1/1/0.90 for N2-N interactions.

  19. Realization of the Energy Saving of the Environmental Examination Device Temperature Control System in Consideration of Temperature Characteristics

    NASA Astrophysics Data System (ADS)

    Onogaki, Hitoshi; Yokoyama, Shuichi

    The temperature control of the environmental examination device has loss of the energy consumption to cool it while warming it. This paper proposed a tempareture control system method with energy saving for the enviromental examination device without using cooling in consideration of temperature characteristics.

  20. Accurate Modelling of a Flexible-Link Planar Mechanism by Means of a Linearized Model in the State-Space Form for Design of a Vibration Controller

    NASA Astrophysics Data System (ADS)

    GASPARETTO, A.

    2001-02-01

    Vibration control of flexible link mechanisms with more than two flexible links is still an open question, mainly because defining a model that is adequate for the designing of a controller is a rather difficult task. In this work, an accurate dynamic non-linear model of a flexible-link planar mechanism is presented. In order to bring the system into a form that is suitable for the design of a vibration controller, the model is then linearized about an operating point, so as to achieve a linear model of the system in the standard state-space form of system theory. The linear model obtained, which is valid for whatever planar mechanism with any number of flexible link, is then applied to a four-bar planar linkage. Extensive simulation is carried out, aimed at comparing the system dynamic evolution, both in the open- and in the closed-loop case, using the non-linear model and the linearized one. The results prove that the error made by using the linearized system instead of the non-linear one is small. Therefore, it can be concluded that the model proposed in this work can constitute an effective basis for designing and testing many types of vibration controllers for flexible planar mechanisms.

  1. Development of an Outdoor Temperature-Based Control Algorithm for Residential Mechanical Ventilation Control

    SciTech Connect

    Less, Brennan; Walker, Iain; Tang, Yihuan

    2014-06-01

    Smart ventilation systems use controls to ventilate more during those periods that provide either an energy or IAQ advantage (or both) and less during periods that provide a dis advantage. Using detailed building simulations, this study addresses one of the simplest and lowest cost types of smart controllers —outdoor temperature- based control. If the outdoor temperature falls below a certain cut- off, the fan is simply turned off. T he main principle of smart ventilation used in this study is to shift ventilation from time periods with large indoor -outdoor temperature differences, to periods where these differences are smaller, and their energy impacts are expected to be less. Energy and IAQ performance are assessed relative to a base case of a continuously operated ventilation fan sized to comply with ASHRAE 62.2-2013 whole house ventilation requirements. In order to satisfy 62.2-2013, annual pollutant exposure must be equivalent between the temperature controlled and continuous fan cases. This requires ventilation to be greater than 62.2 requirements when the ventilation system operates. This is achieved by increasing the mechanical ventilation system air flow rates.

  2. Measurement of Effective Canopy Temperature: The Missing Link to Modeling Transpiration in Controlled Environments

    NASA Technical Reports Server (NTRS)

    Monje, O. A.; McCormack, Ann; Bugbee, Bruce; Jones, Harry W., Jr. (Technical Monitor)

    1994-01-01

    The objectives were to apply energy balance principles to plant canopies, and to determine which parameters are essential for predicting plant canopy transpiration (E) in controlled environments. Transpiration was accurately measured in a gas-exchange system. Absorbed radiation (R(sub abs)) by the canopy was measured with a net radiometer and calculated from short and long-wave radiation components. Average canopy foliar temperature T(sub L) can be measured with an infrared radiometer, but since T(sub L) is seldom uniform, a weighed average measurement of T(sub L) must be made. The effective canopy temperature T(sub C) is that temperature that balances the energy flux between absorbed radiation and latent heat L(sub E) and sensible heat (H) fluxes. TC should exactly equal air temperature T(sub A) when L(sub E) equals R(sub abs). When unnecessary thermal radiation from the lighting system is removed by a water filter, the magnitude of L(sub E) from transpiration approaches Rabs and T(sub C) is close to T(sub A). Unlike field models, we included the energy used in photosynthesis and found that up to 10% of Rabs was used in photosynthesis. We calculated aerodynamic conductance for H from measurements of wind speed and canopy height using the wind profile equation. Canopy aerodynamic conductance ranged from.03 to.04 m/s for wind speeds from.6 to 1 m/s; thus a 0.1 C canopy to air temperature difference results in a sensible heat flux of about 4 W/sq m, which is only 1% of R(sub abs). We examined the ability of wide angle infrared transducers to accurately integrate T(sub L) from the top to the bottom of the canopy. We measured evaporation from the hydroponic media to be approximately 1 micro mol/sq m s or 10% of R(sub abs). This result indicates that separating evaporation from transpiration is more important than exact measurement of canopy temperature.

  3. Compact, accurate description of diagnostic neutral beam propagation and attenuation in a high temperature plasma for charge exchange recombination spectroscopy analysis.

    PubMed

    Bespamyatnov, Igor O; Rowan, William L; Granetz, Robert S

    2008-10-01

    Charge exchange recombination spectroscopy on Alcator C-Mod relies on the use of the diagnostic neutral beam injector as a source of neutral particles which penetrate deep into the plasma. It employs the emission resulting from the interaction of the beam atoms with fully ionized impurity ions. To interpret the emission from a given point in the plasma as the density of emitting impurity ions, the density of beam atoms must be known. Here, an analysis of beam propagation is described which yields the beam density profile throughout the beam trajectory from the neutral beam injector to the core of the plasma. The analysis includes the effects of beam formation, attenuation in the neutral gas surrounding the plasma, and attenuation in the plasma. In the course of this work, a numerical simulation and an analytical approximation for beam divergence are developed. The description is made sufficiently compact to yield accurate results in a time consistent with between-shot analysis.

  4. Loop Heat Pipe Operation Using Heat Source Temperature for Set Point Control

    NASA Technical Reports Server (NTRS)

    Ku, Jentung; Paiva, Kleber; Mantelli, Marcia

    2011-01-01

    Loop heat pipes (LHPs) have been used for thermal control of several NASA and commercial orbiting spacecraft. The LHP operating temperature is governed by the saturation temperature of its compensation chamber (CC). Most LHPs use the CC temperature for feedback control of its operating temperature. There exists a thermal resistance between the heat source to be cooled by the LHP and the LHP's CC. Even if the CC set point temperature is controlled precisely, the heat source temperature will still vary with its heat output. For most applications, controlling the heat source temperature is of most interest. A logical question to ask is: "Can the heat source temperature be used for feedback control of the LHP operation?" A test program has been implemented to answer the above question. Objective is to investigate the LHP performance using the CC temperature and the heat source temperature for feedback control

  5. Electrical detection of C-reactive protein using a single free-standing, thermally controlled piezoresistive microcantilever for highly reproducible and accurate measurements.

    PubMed

    Yen, Yi-Kuang; Lai, Yu-Cheng; Hong, Wei-Ting; Pheanpanitporn, Yotsapoom; Chen, Chuin-Shan; Huang, Long-Sun

    2013-07-29

    This study demonstrates a novel method for electrical detection of C-reactive protein (CRP) as a means of identifying an infection in the body, or as a cardiovascular disease risk assay. The method uses a single free-standing, thermally controlled piezoresistive microcantilever biosensor. In a commonly used sensing arrangement of conventional dual cantilevers in the Wheatstone bridge circuit, reference and gold-coated sensing cantilevers that inherently have heterogeneous surface materials and different multilayer structures may yield independent responses to the liquid environmental changes of chemical substances, flow field and temperature, leading to unwanted signal disturbance for biosensing targets. In this study, the single free-standing microcantilever for biosensing applications is employed to resolve the dual-beam problem of individual responses in chemical solutions and, in a thermally controlled system, to maintain its sensor performance due to the sensitive temperature effect. With this type of single temperature-controlled microcantilever sensor, the electrical detection of various CRP concentrations from 1 µg/mL to 200 µg/mL was performed, which covers the clinically relevant range. Induced surface stresses were measured at between 0.25 N/m and 3.4 N/m with high reproducibility. Moreover, the binding affinity (KD) of CRP and anti-CRP interaction was found to be 18.83 ± 2.99 µg/mL, which agreed with results in previous reported studies. This biosensing technique thus proves valuable in detecting inflammation, and in cardiovascular disease risk assays.

  6. High temperature electrically conducting ceramic heating element and control system

    NASA Technical Reports Server (NTRS)

    Halbach, C. R.; Page, R. J.

    1975-01-01

    Improvements were made in both electrode technology and ceramic conductor quality to increase significantly the lifetime and thermal cycling capability of electrically conducting ceramic heater elements. These elements were operated in vacuum, inert and reducing environments as well as oxidizing atmospheres adding to the versatility of the conducting ceramic as an ohmic heater. Using stabilized zirconia conducting ceramic heater elements, a furnace was fabricated and demonstrated to have excellent thermal response and cycling capability. The furnace was used to melt platinum-20% rhodium alloy (melting point 1904 C) with an isothermal ceramic heating element having a nominal working cavity size of 2.5 cm diameter by 10.0 cm long. The furnace was operated to 1940 C with the isothermal ceramic heating element. The same furnace structure was fitted with a pair of main heater elements to provide axial gradient temperature control over a working cavity length of 17.8 cm.

  7. Tropical cyclone rainfall area controlled by relative sea surface temperature

    PubMed Central

    Lin, Yanluan; Zhao, Ming; Zhang, Minghua

    2015-01-01

    Tropical cyclone rainfall rates have been projected to increase in a warmer climate. The area coverage of tropical cyclones influences their impact on human lives, yet little is known about how tropical cyclone rainfall area will change in the future. Here, using satellite data and global atmospheric model simulations, we show that tropical cyclone rainfall area is controlled primarily by its environmental sea surface temperature (SST) relative to the tropical mean SST (that is, the relative SST), while rainfall rate increases with increasing absolute SST. Our result is consistent with previous numerical simulations that indicated tight relationships between tropical cyclone size and mid-tropospheric relative humidity. Global statistics of tropical cyclone rainfall area are not expected to change markedly under a warmer climate provided that SST change is relatively uniform, implying that increases in total rainfall will be confined to similar size domains with higher rainfall rates. PMID:25761457

  8. Cesium lead iodide solar cells controlled by annealing temperature.

    PubMed

    Kim, Yu Geun; Kim, Tae-Yoon; Oh, Jeong Hyeon; Choi, Kyoung Soon; Kim, Youn-Jea; Kim, Soo Young

    2017-02-22

    An inorganic lead halide perovskite film, CsPbI3, used as an absorber in perovskite solar cells (PSCs) was optimized by controlling the annealing temperature and the layer thickness. The CsPbI3 layer was synthesized by one-step coating of CsI mixed with PbI2 and a HI additive in N,N-dimethylformamide. The annealing temperature of the CsPbI3 film was varied from 80 to 120 °C for different durations and the thickness was controlled by changing the spin-coating rpm. After annealing the CsPbI3 layer at 100 °C under dark conditions for 10 min, a black phase of CsPbI3 was formed and the band gap was 1.69 eV. Most of the yellow spots disappeared, the surface coverage was almost 100%, and the rms roughness was minimized to 3.03 nm after annealing at 100 °C. The power conversion efficiency (PCE) of the CsPbI3 based PSC annealed at 100 °C was 4.88%. This high PCE value is attributed to the low yellow phase ratio, high surface coverage, low rms roughness, lower charge transport resistance, and lower charge accumulation. The loss ratio of the PCE of the CH3NH3PbIxCl3-x and CsPbI3 based PSCs after keeping in air was 47 and 26%, respectively, indicating that the stability of the CsPbI3 based PSC is better than that of the CH3NH3PbIxCl3-x based PSC. From these results, it is evident that CsPbI3 is a potential candidate for solar cell applications.

  9. Improving Forecast Skill by Assimilation of Quality-controlled AIRS Temperature Retrievals under Partially Cloudy Conditions

    NASA Technical Reports Server (NTRS)

    Reale, O.; Susskind, J.; Rosenberg, R.; Brin, E.; Riishojgaard, L.; Liu, E.; Terry, J.; Jusem, J. C.

    2007-01-01

    The National Aeronautics and Space Administration (NASA) Atmospheric Infrared Sounder (AIRS) on board the Aqua satellite has been long recognized as an important contributor towards the improvement of weather forecasts. At this time only a small fraction of the total data produced by AIRS is being used by operational weather systems. In fact, in addition to effects of thinning and quality control, the only AIRS data assimilated are radiance observations of channels unaffected by clouds. Observations in mid-lower tropospheric sounding AIRS channels are assimilated primarily under completely clear-sky conditions, thus imposing a very severe limitation on the horizontal distribution of the AIRS-derived information. In this work it is shown that the ability to derive accurate temperature profiles from AIRS observations in partially cloud-contaminated areas can be utilized to further improve the impact of AIRS observations in a global model and forecasting system. The analyses produced by assimilating AIRS temperature profiles obtained under partial cloud cover result in a substantially colder representation of the northern hemisphere lower midtroposphere at higher latitudes. This temperature difference has a strong impact, through hydrostatic adjustment, in the midtropospheric geopotential heights, which causes a different representation of the polar vortex especially over northeastern Siberia and Alaska. The AIRS-induced anomaly propagates through the model's dynamics producing improved 5-day forecasts.

  10. Improving forecast skill by assimilation of quality-controlled AIRS temperature retrievals under partially cloudy conditions

    NASA Astrophysics Data System (ADS)

    Reale, O.; Susskind, J.; Rosenberg, R.; Brin, E.; Liu, E.; Riishojgaard, L. P.; Terry, J.; Jusem, J. C.

    2008-04-01

    The National Aeronautics and Space Administration (NASA) Atmospheric Infrared Sounder (AIRS) on board the Aqua satellite is now recognized as an important contributor towards the improvement of weather forecasts. At this time only a small fraction of the total data produced by AIRS is being used by operational weather systems. In fact, in addition to effects of thinning and quality control, the only AIRS data assimilated are radiance observations of channels unaffected by clouds. Observations in mid-lower tropospheric sounding AIRS channels are assimilated primarily under completely clear-sky conditions, thus imposing a very severe limitation on the horizontal distribution of the AIRS-derived information. In this work it is shown that the ability to derive accurate temperature profiles from AIRS observations in partially cloud-contaminated areas can be utilized to further improve the impact of AIRS observations in a global model and forecasting system. The analyses produced by assimilating AIRS temperature profiles obtained under partial cloud cover result in a substantially colder representation of the northern hemisphere lower midtroposphere at higher latitudes. This temperature difference has a strong impact, through hydrostatic adjustment, in the midtropospheric geopotential heights, which causes a different representation of the polar vortex especially over northeastern Siberia and Alaska. The AIRS-induced anomaly propagates through the model's dynamics producing improved 5-day forecasts.

  11. Bonding surgical incisions using a temperature-controlled laser system based on a single infrared fiber.

    PubMed

    Gabay, Ilan; Barequet, Irina; Varssano, David; Rosner, Mordechai; Katzir, Abraham

    2013-11-01

    ABSTRACT. Although there has been great interest in laser heating for bonding of surgical incisions in tissues, it has not gained wide acceptance by surgeons. We argue that the main obstacle has been the lack of temperature control, which may lead to a weak bonding. We previously developed a laser bonding system based on two infrared transmitting AgBrCl fibers, one for laser heating and one for temperature control. In view of the inherent limitations of such systems observed in many animal experiments, we developed an improved system based on a single infrared fiber. Besides the decreased dimensions, this system offers many advantages over the two-fiber system. It is less sensitive to accuracy of height and tilt of the fiber distal tip above the tissue, ensuring more accurate heating that can potentially lead to stronger bonding with minimal thermal damage. The system is successfully tested in the soldering of 15 corneal incisions, ex vivo. Histopathology shows little thermal damage and good wound apposition. The average burst pressure is 100±30  mm Hg. These findings indicate the usefulness of the system for ophthalmic surgery as well as other surgical procedures, including endoscopic and robotic surgery.

  12. Determination of equilibrium humidities using temperature and humidity controlled X-ray diffraction (RH-XRD).

    PubMed

    Linnow, Kirsten; Steiger, Michael

    2007-01-30

    Confined growth of crystals in porous building materials is generally considered to be a major cause of damage. We report on the use of X-ray diffraction under controlled conditions of temperature and relative humidity (RH-XRD) for the investigation of potentially deleterious phase transition reactions. An improved procedure based on rate measurements is used for the accurate and reproducible determination of equilibrium humidities of deliquescence and hydration reactions. The deliquescence humidities of NaCl (75.4+/-0.5% RH) and Ca(NO3)2 x 4 H2O (50.8+/-0.7% RH) at 25 degrees C determined with this improved RH-XRD technique are in excellent agreement with available literature data. Measurement of the hydration of anhydrous Ca(NO3)2 to form Ca(NO3)2 x 2 H2O revealed an equilibrium humidity of 10.2+/-0.3%, which is also in reasonable agreement with available data. In conclusion, dynamic X-ray diffraction measurements are an appropriate method for the accurate and precise determination of equilibrium humidities with a number of interesting future applications.

  13. Studying the Protein Quality Control System of D. discoideum Using Temperature-controlled Live Cell Imaging

    PubMed Central

    Malinovska, Liliana; Alberti, Simon

    2016-01-01

    The complex lifestyle of the social amoebae Dictyostelium discoideum makes it a valuable model for the study of various biological processes. Recently, we showed that D. discoideum is remarkably resilient to protein aggregation and can be used to gain insights into the cellular protein quality control system. However, the use of D. discoideum as a model system poses several challenges to microscopy-based experimental approaches, such as the high motility of the cells and their susceptibility to photo-toxicity. The latter proves to be especially challenging when studying protein homeostasis, as the phototoxic effects can induce a cellular stress response and thus alter to behavior of the protein quality control system. Temperature increase is a commonly used way to induce cellular stress. Here, we describe a temperature-controllable imaging protocol, which allows observing temperature-induced perturbations in D. discoideum. Moreover, when applied at normal growth temperature, this imaging protocol can also noticeably reduce photo-toxicity, thus allowing imaging with higher intensities. This can be particularly useful when imaging proteins with very low expression levels. Moreover, the high mobility of the cells often requires the acquisition of multiple fields of view to follow individual cells, and the number of fields needs to be balanced against the desired time interval and exposure time. PMID:28060267

  14. Low temperature carrier transport properties in isotopically controlled germanium

    SciTech Connect

    Itoh, Kohei

    1994-12-01

    Investigations of electronic and optical properties of semiconductors often require specimens with extremely homogeneous dopant distributions and precisely controlled net-carrier concentrations and compensation ratios. The previous difficulties in fabricating such samples are overcome as reported in this thesis by growing high-purity Ge single crystals of controlled 75Ge and 70Ge isotopic compositions, and doping these crystals by the neutron transmutation doping (NTD) technique. The resulting net-impurity concentrations and the compensation ratios are precisely determined by the thermal neutron fluence and the [74Ge]/[70Ge] ratios of the starting Ge materials, respectively. This method also guarantees unprecedented doping uniformity. Using such samples the authors have conducted four types of electron (hole) transport studies probing the nature of (1) free carrier scattering by neutral impurities, (2) free carrier scattering by ionized impurities, (3) low temperature hopping conduction, and (4) free carrier transport in samples close to the metal-insulator transition.

  15. Device and method for self-verifying temperature measurement and control

    DOEpatents

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

    2002-10-29

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

  16. 46 CFR 154.701 - Cargo pressure and temperature control: General.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 5 2013-10-01 2013-10-01 false Cargo pressure and temperature control: General. 154.701 Section 154.701 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CERTAIN BULK DANGEROUS... Equipment Cargo Pressure and Temperature Control § 154.701 Cargo pressure and temperature control:...

  17. 46 CFR 154.701 - Cargo pressure and temperature control: General.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 5 2010-10-01 2010-10-01 false Cargo pressure and temperature control: General. 154.701 Section 154.701 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CERTAIN BULK DANGEROUS... Equipment Cargo Pressure and Temperature Control § 154.701 Cargo pressure and temperature control:...

  18. 46 CFR 154.701 - Cargo pressure and temperature control: General.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 5 2014-10-01 2014-10-01 false Cargo pressure and temperature control: General. 154.701 Section 154.701 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CERTAIN BULK DANGEROUS... Equipment Cargo Pressure and Temperature Control § 154.701 Cargo pressure and temperature control:...

  19. 46 CFR 154.701 - Cargo pressure and temperature control: General.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 5 2012-10-01 2012-10-01 false Cargo pressure and temperature control: General. 154.701 Section 154.701 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CERTAIN BULK DANGEROUS... Equipment Cargo Pressure and Temperature Control § 154.701 Cargo pressure and temperature control:...

  20. 46 CFR 154.701 - Cargo pressure and temperature control: General.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 5 2011-10-01 2011-10-01 false Cargo pressure and temperature control: General. 154.701 Section 154.701 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CERTAIN BULK DANGEROUS... Equipment Cargo Pressure and Temperature Control § 154.701 Cargo pressure and temperature control:...

  1. Extrinsic Fabry-Perot interferometry for noncontact temperature control of nanoliter-volume enzymatic reactions in glass microchips.

    PubMed

    Easley, Christopher J; Legendre, Lindsay A; Roper, Michael G; Wavering, Thomas A; Ferrance, Jerome P; Landers, James P

    2005-02-15

    Optical fiber extrinsic Fabry-Perot interferometry (EFPI) was investigated as a noncontact temperature sensor and utilized for regulating the temperature of small-volume solutions in microchips. Interference pattern analysis determined the optical path lengths (OPL) associated with reflections from various surfaces on or in the microchip, in particular, from gold sputtered on the bottom of a microchannel. Since OPL is directly proportional to refractive index, which is dependent on solution temperature, the EFPI sensor was capable of noncontact monitoring of solution temperature simply from alterations in the measured path length. Calibration of the sensor against a thermocouple was performed while heating the microchip in a noncontact manner with an IR lamp. The combination of EFPI temperature sensor, IR-mediated heating, and air cooling allowed a fully noncontact system for small-volume temperature control in microchip structures, and its utility was illustrated by optimal digestion of DNA by a temperature-dependent restriction endonuclease in 320 nL. The functionality and simplicity of the microchip EFPI temperature sensor was enhanced by replacing the prebonding sputtered gold with a tunable, chemically plated semireflective silver coating created in situ after chip fabrication. This provided an 8-fold improvement in the lowest detectable temperature change (deltaT = 0.1 degrees C), facilitated primarily by enhanced reflection from both the bottom and top surfaces of the microchannel. This approach for controlling micro- and nanoscale reactions--with heating, cooling, and temperature control being carried out in a completely noncontact fashion--provides an accurate and sensitive method for executing chemical and biochemical reactions in microchips.

  2. Hot roller embossing system equipped with a temperature margin-based controller

    SciTech Connect

    Kim, Seyoung Son, Youngsu; Lee, Sunghee; Ham, Sangyong; Kim, Byungin

    2014-08-15

    A temperature control system was proposed for hot roller embossing. The roll surface was heated using induction coils and cooled with a circulating chilled water system. The temperature of the roll surface was precisely controlled by a temperature margin-based control algorithm that we developed. Implementation of the control system reduced deviations in the roll surface temperature to less than ±2 °C. The tight temperature control and the ability to rapidly increase and decrease the roll temperature will allow optimum operating parameters to be developed quickly. The temperature margin-based controller could also be used to optimize the time course of electrical power and shorten the cooling time by choosing an appropriate temperature margin, possibly for limited power consumption. The chiller-equipped heating roll with the proposed control algorithm is expected to decrease the time needed to determine the optimal embossing process.

  3. High-resolution separation and accurate size determination in pulsed-field gel electrophoresis of DNA. 1. DNA size standards and the effect of agarose and temperature

    SciTech Connect

    Mathew, M.K.; Smith, C.L.; Cantor, C.R. )

    1988-12-27

    Pulsed-field gel electrophoresis (PGF) subjects DNA alternately to two electrical fields to resolve DNA ranging from 10,000 base pairs (10 kb) to 10,000 kb in size. The separations are quite sensitive to a variety of experimental variables. This makes it critical to have a wide range of reliable size standards. A technique is described for preparing mixtures of bacteriophage DNA oligomers that span a size range from monomer to more than 30-mer. The relationship between size and mobility of oligomers of different bacteriophage DNA monomers is generally self-consistent. Thus, these samples can serve as primary length standards for DNAs ranging from 10 kb to more than 1,500 kb. They have been used to estimate the size of the chromosomal DNAs from various Saccharomyces cerevisiae strains and to test the effect of gel concentration and temperature on PFG. DNA resolution during PFG is slightly improved in agarose gels with small pore sizes, in contrast to continuous electrophoresis where the opposite is observed. PFG mobility is surprisingly sensitive to changes in the running temperature.

  4. The Temperature Fuzzy Control System of Barleythe Malt Drying Based on Microcontroller

    NASA Astrophysics Data System (ADS)

    Gao, Xiaoyang; Bi, Yang; Zhang, Lili; Chen, Jingjing; Yun, Jianmin

    The control strategy of temperature and humidity in the beer barley malt drying chamber based on fuzzy logic control was implemented.Expounded in this paper was the selection of parameters for the structure of the regulatory device, as well as the essential design from control rules based on the existing experience. A temperature fuzzy controller was thus constructed using relevantfuzzy logic, and humidity control was achieved by relay, ensured the situation of the humidity to control the temperature. The temperature's fuzzy control and the humidity real-time control were all processed by single chip microcomputer with assembly program. The experimental results showed that the temperature control performance of this fuzzy regulatory system,especially in the ways of working stability and responding speed and so on,was better than normal used PID control. The cost of real-time system was inquite competitive position. It was demonstrated that the system have a promising prospect of extensive application.

  5. Control of skin blood flow, sweating, and heart rate - Role of skin vs. core temperature

    NASA Technical Reports Server (NTRS)

    Wyss, C. R.; Brengelmann, G. L.; Johnson, J. M.; Rowell, L. B.; Niederberger, M.

    1974-01-01

    A study was conducted to generate quantitative expressions for the influence of core temperature, skin temperature, and the rate of change of skin temperature on sweat rate, skin blood flow, and heart rate. A second goal of the study was to determine whether the use of esophageal temperature rather than the right atrial temperature as a measure of core temperature would lead to different conclusions about the control of measured effector variables.

  6. Temperature imaging with ultrasonic transmission tomography for treatment control

    NASA Astrophysics Data System (ADS)

    Chu, Zheqi; Pinter, Stephen. Z.; Yuan, Jie; Scarpelli, Matthew L.; Kripfgans, Oliver D.; Fowlkes, J. Brian; Duric, Neb; Carson, Paul L.

    2017-03-01

    Hyperthermia is a promising method to enhance chemo- or radiation therapy of breast cancer and the time-temperature profile in the target and surrounding areas is the primary monitoring method. Unlike with thermal ablation of lesions, in hyperthermia there are not good alternative treatment monitoring quantities. However, there is less problem with non-monotonic thermal coefficients of speed of sound used with ultrasonic imaging of temperature. This paper tests a long discussed but little investigated method of imaging temperature using speed of sound and proposes methods of reducing edge enhancement artifacts in the temperature image. Normally, when directly using the speed of sound to reconstruct the temperature image around the tumor, there will be an abnormal bipolar edge enhancement along the boundary between two materials with different speeds of sound at a given temperature. This due to partial volume effects and can be diminished by regularized, weighted deconvolution. An initial, manual deconvolution is shown, as well as an EMD (Empirical Mode Decomposition) method. Here we use the continuity and other constraints to choose the coefficient, reprocess the temperature field image and take the mean variations of the temperature in the adjacent pixels as the judgment criteria. Both methods effectively reduce the edge enhancement and produce a more precise image of temperature.

  7. Energy Consumption and Control Response Evaluations of AODV Routing in WSANs for Building-Temperature Control

    PubMed Central

    Booranawong, Apidet; Teerapabkajorndet, Wiklom; Limsakul, Chusak

    2013-01-01

    The main objective of this paper is to investigate the effects of routing protocols on wireless sensor and actuator networks (WSANs), focusing on the control system response and the energy consumption of nodes in a network. We demonstrate that routing algorithms designed without considering the relationship between communication and control cannot be appropriately used in wireless networked control applications. For this purpose, an ad-hoc on-demand distance vector (AODV) routing, an IEEE 802.15.4, and a building-temperature control system are employed for this exploration. The findings from our scenarios show that the AODV routing can select a path with a high traffic load for data transmission. It takes a long time before deciding to change a new route although it experiences the unsuccessful transmission of packets. As a result, the desirable control target cannot be achieved in time, and nodes consume more energy due to frequent packet collisions and retransmissions. Consequently, we propose a simple routing solution to alleviate these research problems by modifying the original AODV routing protocol. The delay-threshold is considered to avoid any congested connection during routing procedures. The simulation results demonstrate that our solution can be appropriately applied in WSANs. Both the energy consumption and the control system response are improved. PMID:23807689

  8. TEMPERATURE AND MOISTURE CONTROL OF SEED AGING IN RYE

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The interactions between temperature and moisture that regulate seed aging were measured using rye seeds. Experiments include a number of long term storage studies under conditions of varying relative humidity (RH), water content and temperature. Decrease in germination percentage and radicle leng...

  9. Regional amplification of projected changes in extreme temperatures strongly controlled by soil moisture-temperature feedbacks

    NASA Astrophysics Data System (ADS)

    Vogel, M. M.; Orth, R.; Cheruy, F.; Hagemann, S.; Lorenz, R.; Hurk, B. J. J. M.; Seneviratne, S. I.

    2017-02-01

    Regional hot extremes are projected to increase more strongly than global mean temperature, with substantially larger changes than 2°C even if global warming is limited to this level. We investigate the role of soil moisture-temperature feedbacks for this response based on multimodel experiments for the 21st century with either interactive or fixed (late 20th century mean seasonal cycle) soil moisture. We analyze changes in the hottest days in each year in both sets of experiments, relate them to the global mean temperature increase, and investigate processes leading to these changes. We find that soil moisture-temperature feedbacks significantly contribute to the amplified warming of the hottest days compared to that of global mean temperature. This contribution reaches more than 70% in Central Europe and Central North America. Soil moisture trends are more important for this response than short-term soil moisture variability. These results are relevant for reducing uncertainties in regional temperature projections.

  10. Loop Heat Pipe Operation Using Heat Source Temperature for Set Point Control

    NASA Technical Reports Server (NTRS)

    Ku, Jentung; Paiva, Kleber; Mantelli, Marcia

    2011-01-01

    The LHP operating temperature is governed by the saturation temperature of its reservoir. Controlling the reservoir saturation temperature is commonly accomplished by cold biasing the reservoir and using electrical heaters to provide the required control power. Using this method, the loop operating temperature can be controlled within +/- 0.5K. However, because of the thermal resistance that exists between the heat source and the LHP evaporator, the heat source temperature will vary with its heat output even if LHP operating temperature is kept constant. Since maintaining a constant heat source temperature is of most interest, a question often raised is whether the heat source temperature can be used for LHP set point temperature control. A test program with a miniature LHP has been carried out to investigate the effects on the LHP operation when the control temperature sensor is placed on the heat source instead of the reservoir. In these tests, the LHP reservoir is cold-biased and is heated by a control heater. Tests results show that it is feasible to use the heat source temperature for feedback control of the LHP operation. Using this method, the heat source temperature can be maintained within a tight range for moderate and high powers. At low powers, however, temperature oscillations may occur due to interactions among the reservoir control heater power, the heat source mass, and the heat output from the heat source. In addition, the heat source temperature could temporarily deviate from its set point during fast thermal transients. The implication is that more sophisticated feedback control algorithms need to be implemented for LHP transient operation when the heat source temperature is used for feedback control.

  11. Automated control and monitoring of thermal processing using high temperature, short time pasteurization.

    PubMed

    Schlesser, J E; Armstrong, D J; Cinar, A; Ramanauskas, P; Negiz, A

    1997-10-01

    High temperature, short time pasteurization was used to evaluate a computer-based system for controlling the pasteurization process, acquiring data, and monitoring records. Software was used for the control of hot water temperature, flow rate through the centrifugal timing pump, and diversion of under-processed product. Three types of control strategies were conducted: single loop, cascade, and multivariable. The single loop control strategy showed the most rapid responses to temperature changes, but the temperature response curve was slowest to return to its set point. The cascade control strategy showed slower recoveries to temperature changes, but the temperature response curve was smoother. The multivariable control strategy responded slightly faster than the cascade control strategy, and the temperature response curve was slightly smoother than the cascade control strategy. The multivariable control strategy was able to control the flow diversion valve by the use of a lethality controller. The data acquisition system, used to monitor the data obtained from the high temperature, short-time pasteurization system, was within +/- 0.1 degree C of the temperature recorded by the safety thermal limit recorder. Reliability was determined by examining the changes in the position of the flow diversion valve to identify process deviations and by comparing the changes to the event marker on circular charts. The data acquisition system was an effective alternative for monitoring the completeness of data.

  12. The timing of the human circadian clock is accurately represented by the core body temperature rhythm following phase shifts to a three-cycle light stimulus near the critical zone

    NASA Technical Reports Server (NTRS)

    Jewett, M. E.; Duffy, J. F.; Czeisler, C. A.

    2000-01-01

    A double-stimulus experiment was conducted to evaluate the phase of the underlying circadian clock following light-induced phase shifts of the human circadian system. Circadian phase was assayed by constant routine from the rhythm in core body temperature before and after a three-cycle bright-light stimulus applied near the estimated minimum of the core body temperature rhythm. An identical, consecutive three-cycle light stimulus was then applied, and phase was reassessed. Phase shifts to these consecutive stimuli were no different from those obtained in a previous study following light stimuli applied under steady-state conditions over a range of circadian phases similar to those at which the consecutive stimuli were applied. These data suggest that circadian phase shifts of the core body temperature rhythm in response to a three-cycle stimulus occur within 24 h following the end of the 3-day light stimulus and that this poststimulus temperature rhythm accurately reflects the timing of the underlying circadian clock.

  13. Temperature control of thermal radiation from composite bodies

    NASA Astrophysics Data System (ADS)

    Jin, Weiliang; Polimeridis, Athanasios G.; Rodriguez, Alejandro W.

    2016-03-01

    We demonstrate that recent advances in nanoscale thermal transport and temperature manipulation can be brought to bear on the problem of tailoring thermal radiation from wavelength-scale composite bodies. We show that such objects—complicated arrangements of phase-change chalcogenide (Ge2Sb2Te5 ) glasses and metals or semiconductors—can be designed to exhibit strong resonances and large temperature gradients, which in turn lead to large and highly directional emission at midinfrared wavelengths. We find that partial directivity depends sensitively on a complicated interplay between shape, material dispersion, and temperature localization within the objects, requiring simultaneous design of the electromagnetic scattering and thermal properties of these structures. Our calculations exploit a recently developed fluctuating-volume current formulation of electromagnetic fluctuations that rigorously captures radiation phenomena in structures with strong temperature and dielectric inhomogeneities, such as those studied here.

  14. Parametric sensitivity analysis for temperature control in outdoor photobioreactors.

    PubMed

    Pereira, Darlan A; Rodrigues, Vinicius O; Gómez, Sonia V; Sales, Emerson A; Jorquera, Orlando

    2013-09-01

    In this study a critical analysis of input parameters on a model to describe the broth temperature in flat plate photobioreactors throughout the day is carried out in order to assess the effect of these parameters on the model. Using the design of experiment approach, variation of selected parameters was introduced and the influence of each parameter on the broth temperature was evaluated by a parametric sensitivity analysis. The results show that the major influence on the broth temperature is that from the reactor wall and the shading factor, both related to the direct and reflected solar irradiation. Other parameter which play an important role on the temperature is the distance between plates. This study provides information to improve the design and establish the most appropriate operating conditions for the cultivation of microalgae in outdoor systems.

  15. Determination of the temperature-dependent cell membrane permeabilities using microfluidics with integrated flow and temperature control.

    PubMed

    Fang, Cifeng; Ji, Fujun; Shu, Zhiquan; Gao, Dayong

    2017-02-28

    We developed an integrated microfluidic platform for instantaneous flow and localized temperature control. The platform consisted of a flow-focusing region for sample delivery and a cross-junction region embedded with a microheater for cell trapping and localized temperature control by using an active feedback control system. We further used it to measure the membrane transport properties of Jurkat cells, including the osmotically inactive cell volume (Vb) and cell membrane permeabilities to water (Lp) and to cryoprotective agent (CPA) solutions (dimethyl sulfoxide (DMSO) in this study) (PS) at various temperatures (room temperature, 30 °C, and 37 °C). Such characteristics of cells are of great importance in many applications, especially in optimal cryopreservation. With the results, the corresponding activation energy for water and CPA transport was calculated. The comparison of the results from the current study with reference data indicates that the developed platform is a reliable tool for temperature-dependent cell behavior study, which provides valuable tools for general cell manipulation applications with precise temperature control.

  16. Tuning the local temperature during feedback controlled electromigration in gold nanowires

    SciTech Connect

    Xiang, An; Hou, Shimin Liao, Jianhui

    2014-06-02

    Feedback controlled electromigration (FCE) in metallic nanowires has been widely used for various purposes. However, the control of the local temperature during FCE remains a challenge. Here, we report that the environment temperature can be used as a knob to tune the local temperature during FCE in gold nanowires. FCE was performed in gold nanowires at various environment temperatures ranging from 4.2 K to 300 K. We find that the dissipated power normalized by the cross section area of the nano constriction is linearly proportional to the environment temperature. Interestingly, the estimated local maximum temperature parabolically depends on the environment temperature. A minimum in the local temperature can be reached if an appropriate environment temperature is chosen. Our findings are well supported by the finite element simulation. Moreover, the data indicates the coupling between FCE triggering current density and local temperature.

  17. Temperature control and measurement with tunable femtosecond optical tweezers

    NASA Astrophysics Data System (ADS)

    Mondal, Dipankar; Goswami, Debabrata

    2016-09-01

    We present the effects of wavelength dependent temperature rise in a femtosecond optical tweezers. Our experiments involve the femtosecond trapping laser tunable from 740-820 nm at low power 25 mW to cause heating in the trapped volume within a homogeneous solution of sub micro-molar concentration of IR dye. The 780 nm high repetition rate laser acts as a resonant excitation source which helps to create the local heating effortlessly within the trapping volume. We have used both position autocorrelation and equipartion theorem to evaluate temperature at different wavelength having different absorption coefficient. Fixing the pulse width in the temporal domain gives constant bandwidth at spatial domain, which makes our system behave as a tunable temperature rise device with high precision. This observation leads us to calculate temperature as well as viscosity within the vicinity of the trapping zone. A mutual energy transfer occurs between the trapped bead and solvents that leads to transfer the thermal energy of solvents into the kinetic energy of the trap bead and vice-versa. Thus hot solvated molecules resulting from resonant and near resonant excitation of trapping wavelength can continuously dissipate heat to the trapped bead which will be reflected on frequency spectrum of Brownian noise exhibited by the bead. Temperature rise near the trapping zone can significantly change the viscosity of the medium. We observe temperature rise profile according to its Gaussian shaped absorption spectrum with different wavelength.

  18. Temperature control during diode laser welding in a human cornea

    NASA Astrophysics Data System (ADS)

    Rossi, Francesca; Matteini, Paolo; Pini, Roberto; Menabuoni, Luca

    2007-07-01

    Diode laser welding is a technique proposed in ophthalmic surgery to induce immediate sealing of clear corneal wounds. The welding effect is achieved irradiating the area, previously treated with a chromophore, by the use of a low power diode laser: the resulting thermal effect induces structural modifications in the stromal collagen, that welds upon cooling. We present a study on the temperature dynamics developing during welding in a human eye. An infrared thermocamera was used to measure the temperature variations on the surface of the cornea during clinical penetrating keratoplasty (corneal transplant). The experimental data were used as a starting point for a theoretical investigation of the temperature rising inside the ocular structures: we developed a mathematical model based on the bio-heat equation and solved by the use of the Finite Element Method (FEM). The predictive accuracy was verified by comparing the temperature post-processing description with the results obtained from the thermographic data. The model was then used to study the temperature rise and heat propagation inside the eye. Experimental results and model analysis indicated the occurrence of heat confinement during the treatment procedure and a modest enhancement of the temperature (reaching about 55°C inside the laser treated wound), thus evidencing the safety of the procedure in clinical applications.

  19. A versatile phenomenological model for the S-shaped temperature dependence of photoluminescence energy for an accurate determination of the exciton localization energy in bulk and quantum well structures

    NASA Astrophysics Data System (ADS)

    Dixit, V. K.; Porwal, S.; Singh, S. D.; Sharma, T. K.; Ghosh, Sandip; Oak, S. M.

    2014-02-01

    Temperature dependence of the photoluminescence (PL) peak energy of bulk and quantum well (QW) structures is studied by using a new phenomenological model for including the effect of localized states. In general an anomalous S-shaped temperature dependence of the PL peak energy is observed for many materials which is usually associated with the localization of excitons in band-tail states that are formed due to potential fluctuations. Under such conditions, the conventional models of Varshni, Viña and Passler fail to replicate the S-shaped temperature dependence of the PL peak energy and provide inconsistent and unrealistic values of the fitting parameters. The proposed formalism persuasively reproduces the S-shaped temperature dependence of the PL peak energy and provides an accurate determination of the exciton localization energy in bulk and QW structures along with the appropriate values of material parameters. An example of a strained InAs0.38P0.62/InP QW is presented by performing detailed temperature and excitation intensity dependent PL measurements and subsequent in-depth analysis using the proposed model. Versatility of the new formalism is tested on a few other semiconductor materials, e.g. GaN, nanotextured GaN, AlGaN and InGaN, which are known to have a significant contribution from the localized states. A quantitative evaluation of the fractional contribution of the localized states is essential for understanding the temperature dependence of the PL peak energy of bulk and QW well structures having a large contribution of the band-tail states.

  20. An Improved Tumour Temperature Measurement and Control Method for Superficial Tumour Ultrasound Hyperthermia Therapeutic System

    NASA Astrophysics Data System (ADS)

    Shen1, G. F.; Chen, Y. Z.; Ren, G. X.

    2006-10-01

    In tumour hyperthermia therapy, the research on measurement and control of tumour temperature is very important. Based on the hardware platform of superficial tumour ultrasound hyperthermia therapeutic system, an improved tumour temperature measurement and control method is presented in this paper. The experiment process, data and results are discussed in detail. The improved method will greatly reduce the pain and dread of the patients during the therapy period on the tumour temperature measurement and control by using the pinhead sensor.

  1. Toward accurate thermochemistry of the {sup 24}MgH, {sup 25}MgH, and {sup 26}MgH molecules at elevated temperatures: Corrections due to unbound states

    SciTech Connect

    Szidarovszky, Tamás; Császár, Attila G.

    2015-01-07

    The total partition functions Q(T) and their first two moments Q{sup ′}(T) and Q{sup ″}(T), together with the isobaric heat capacities C{sub p}(T), are computed a priori for three major MgH isotopologues on the temperature range of T = 100–3000 K using the recent highly accurate potential energy curve, spin-rotation, and non-adiabatic correction functions of Henderson et al. [J. Phys. Chem. A 117, 13373 (2013)]. Nuclear motion computations are carried out on the ground electronic state to determine the (ro)vibrational energy levels and the scattering phase shifts. The effect of resonance states is found to be significant above about 1000 K and it increases with temperature. Even very short-lived states, due to their relatively large number, have significant contributions to Q(T) at elevated temperatures. The contribution of scattering states is around one fourth of that of resonance states but opposite in sign. Uncertainty estimates are given for the possible error sources, suggesting that all computed thermochemical properties have an accuracy better than 0.005% up to 1200 K. Between 1200 and 2500 K, the uncertainties can rise to around 0.1%, while between 2500 K and 3000 K, a further increase to 0.5% might be observed for Q{sup ″}(T) and C{sub p}(T), principally due to the neglect of excited electronic states. The accurate thermochemical data determined are presented in the supplementary material for the three isotopologues of {sup 24}MgH, {sup 25}MgH, and {sup 26}MgH at 1 K increments. These data, which differ significantly from older standard data, should prove useful for astronomical models incorporating thermodynamic properties of these species.

  2. Wide-Temperature Electronics for Thermal Control of Nanosats

    NASA Technical Reports Server (NTRS)

    Dickman, John Ellis; Gerber, Scott

    2000-01-01

    This document represents a presentation which examines the wide and low-temperature electronics required for NanoSatellites. In the past, larger spacecraft used Radioisotope Heating Units (RHU's). The advantage of the use of these electronics is that they could eliminate or reduce the requirement for RHU's, reduce system weight and simplify spacecraft design by eliminating containment/support structures for RHU's. The Glenn Research Center's Wide/Low Temperature Power Electronics Program supports the development of power systems capable of reliable, efficient operation over wide and low temperature ranges. Included charts review the successes and failures of various electronic devices, the IRF541 HEXFET, The NE76118n-Channel GaAS MESFET, the Lithium Carbon Monofluoride Primary Battery, and a COTS DC-DC converter. The preliminary result of wide/low temperature testing of CTS and custom parts and power circuit indicate that through careful selection of components and technologies it is possible to design and build power circuits which operate from room temperature to near 100K.

  3. Uv Photodissociation Spectroscopy of Temperature Controlled Hydrated Phenol Cluster Cation

    NASA Astrophysics Data System (ADS)

    Kurusu, Itaru; Yagi, Reona; Kasahara, Yasutoshi; Ishikawa, Haruki

    2016-06-01

    Owing to various developments of spectroscopic techniques, microscopic hydration structures of various clusters in the gas phase have been determined so far. The next step for further understanding of the microscopic hydration is to reveal the temperature effect, such as a fluctuation of the hydration structure. Thus, we have been carrying out photodissociation spectroscopy on the hydrated phenol cation clusters, [PhOH(H_2O)_n]^+, trapped in our temperature-variable ion trap. After the last symposium, we succeeded in improving our experimental condition and recorded the UV photodissociation spectra of [PhOH(H_2O)_5]^+ at the trap temperatures of 20, 50, and 100 K. We identified three groups of bands by their temperature dependence in the spectra. Based on the results of the DFT calculations, we estimated the temperature dependence of the relative populations among the isomers. As a results, the isomers were grouped into three groups having different motifs of the hydrogen-bond structures. Comparing the experimental with the theoretical results, we assigned the relation between the band carriers and the hydrogen-bond structure motifs. Details of the discussion will be presented in the paper. H. Ishikawa, T. Nakano, T. Eguchi, T. Shibukawa, K. Fuke, Chem. Phys. Lett. 514, 234 (2011) R. Yagi, Y. Kasahara, H. Ishikawa, WH12, the 70th International Symposium on Molecular Spectroscopy (2015)

  4. Temperature-time issues in bioburden control for planetary protection

    NASA Astrophysics Data System (ADS)

    Clark, Benton C.

    2004-01-01

    Heat energy, administered in the form of an elevated temperature heat soak over a specific interval of time, is a well-known method for inactivating organisms. Sterilization protocols, from commercial pasteurization to laboratory autoclaving, specify both temperature and time, as well as water activity, for treatments to achieve either acceptable reduction of bioburden or complete sterilization. In practical applications of planetary protection, whether to reduce spore load in forward or roundtrip contamination, or to exterminate putative organisms in returned samples from bodies suspected of possible life, avoidance of expensive or potentially damaging treatments of hardware (or samples) could be accomplished if reciprocal relationships between time duration and soak temperature could be established. Conservative rules can be developed from consideration of empirical test data, derived relationships, current standards and various theoretical or proven mechanisms for thermal damage to biological systems.

  5. Temperature-Time Issues in Bioburden Control for Planetary Protection

    NASA Astrophysics Data System (ADS)

    Clark, B.

    Heat energy, administered in the form of an elevated temperature heat soak over a specific interval of time, is a well-known method of inactivating organisms. Ster- ilization protocols, from commercial pasteurization to laboratory autoclaving, specify both the temperature and the time, as well as water activity, for treatments to achieve either acceptable reduction of bioburden or complete sterilization. In practical applications of planetary protection, whether to reduce spore load in for- ward or roundtrip contamination, or to exterminate putative organisms in returned samples from planetary bodies suspected of possible life, avoidance of expensive or potentially damaging treatments of hardware (or samples) could be accomplished if reciprocal relationships between time duration and soak temperature could be established. Conservative rules can be developed from consideration of empirical test data, derived relationships, current standards and various theoretical or proven mechanisms for thermal damage to biological systems.

  6. High temperature sensor/microphone development for active noise control

    NASA Technical Reports Server (NTRS)

    Shrout, Thomas R.

    1993-01-01

    The industrial and scientific communities have shown genuine interest in electronic systems which can operate at high temperatures, among which are sensors to monitor noise, vibration, and acoustic emissions. Acoustic sensing can be accomplished by a wide variety of commercially available devices, including: simple piezoelectric sensors, accelerometers, strain gauges, proximity sensors, and fiber optics. Of the several sensing mechanisms investigated, piezoelectrics were found to be the most prevalent, because of their simplicity of design and application and, because of their high sensitivity over broad ranges of frequencies and temperature. Numerous piezoelectric materials are used in acoustic sensors today; but maximum use temperatures are imposed by their transition temperatures (T(sub c)) and by their resistivity. Lithium niobate, in single crystal form, has the highest operating temperature of any commercially available material, 650 C; but that is not high enough for future requirements. Only two piezoelectric materials show potential for use at 1000 C; AlN thin film reported to be piezoactive at 1150 C, and perovskite layer structure (PLS) materials, which possess among the highest T(sub c) (greater than 1500 C) reported for ferroelectrics. A ceramic PLS composition was chosen. The solid solution composition, 80% strontium niobate (SN) and 20% strontium tantalate (STa), with a T(sub c) approximately 1160 C, was hot forged, a process which concurrently sinters and renders the plate-like grains into a highly oriented configuration to enhance piezo properties. Poled samples of this composition showed coupling (k33) approximately 6 and piezoelectric strain constant (d33) approximately 3. Piezoactivity was seen at 1125 C, the highest temperature measurement reported for a ferroelectric ceramic. The high temperature piezoelectric responses of this, and similar PLS materials, opens the possibility of their use in electronic devices operating at temperatures up to

  7. Phase change material for temperature control and material storage

    NASA Technical Reports Server (NTRS)

    Wessling, Jr., Francis C. (Inventor); Blackwood, James M. (Inventor)

    2011-01-01

    A phase change material comprising a mixture of water and deuterium oxide is described, wherein the mole fraction of deuterium oxide is selected so that the mixture has a selected phase change temperature within a range between 0.degree. C. and 4.degree. C. The mixture is placed in a container and used for passive storage and transport of biomaterials and other temperature sensitive materials. Gels, nucleating agents, freezing point depression materials and colorants may be added to enhance the characteristics of the mixture.

  8. Control of column temperature in reversed-phase liquid chromatography.

    PubMed

    Wolcott, R G; Dolan, J W; Snyder, L R; Bakalyar, S R; Arnold, M A; Nichols, J A

    2000-02-11

    When separations by reversed-phase liquid chromatography (RP-LC) are carried out at temperatures other than ambient, resulting retention times and bandwidths can depend on the equipment used. As a result, an RP-LC separation that is adequate when carried out on one LC system may prove inadequate when the separation is repeated on a second system. In the present study, various temperature-related problems which can result in a failure of method transfer for non-ambient RP-LC methods were examined. Means for correcting for such effects and thereby ensuring method transferability are described.

  9. Basic factors controlling pest in high temperature systems

    NASA Technical Reports Server (NTRS)

    Berkowitz-Mattuck, J.; Rossetti, M.

    1971-01-01

    The catastrophic disintegration in air at intermediate temperatures of refractory materials which are very resistant to oxidation at high temperatures is known as pest. A study was undertaken to determine whether the mechanism proposed for pest failure in silicides might also be responsible for pest failure in NbAl3. The aim was to correlate oxidation kinetics in the range where disintegration of NbAl3 is observed with delayed failure data obtained under similar conditions. Studies were also undertaken to develop some understanding of deformation mechanisms in both silicides and aluminides.

  10. Turbidity, light, temperature, and hydropeaking control primary productivity in the Colorado River, Grand Canyon

    USGS Publications Warehouse

    Hall, Robert O.; Yackulic, Charles B.; Kennedy, Theodore A.; Yard, Michael D.; Rosi-Marshall, Emma J.; Voichick, Nicholas; Behn, Kathrine E.

    2015-01-01

    Dams and river regulation greatly alter the downstream environment for gross primary production (GPP) because of changes in water clarity, flow, and temperature regimes. We estimated reach-scale GPP in five locations of the regulated Colorado River in Grand Canyon using an open channel model of dissolved oxygen. Benthic GPP dominates in Grand Canyon due to fast transport times and low pelagic algal biomass. In one location, we used a 738 days time series of GPP to identify the relative contribution of different physical controls of GPP. We developed both linear and semimechanistic time series models that account for unmeasured temporal covariance due to factors such as algal biomass dynamics. GPP varied from 0 g O2 m−2 d−1 to 3.0 g O2 m−2 d−1 with a relatively low annual average of 0.8 g O2 m−2d−1. Semimechanistic models fit the data better than linear models and demonstrated that variation in turbidity primarily controlled GPP. Lower solar insolation during winter and from cloud cover lowered GPP much further. Hydropeaking lowered GPP but only during turbid conditions. Using the best model and parameter values, the model accurately predicted seasonal estimates of GPP at 3 of 4 upriver sites and outperformed the linear model at all sites; discrepancies were likely from higher algal biomass at upstream sites. This modeling approach can predict how changes in physical controls will affect relative rates of GPP throughout the 385 km segment of the Colorado River in Grand Canyon and can be easily applied to other streams and rivers.

  11. Lithology and temperature: How key mantle variables control rift volcanism

    NASA Astrophysics Data System (ADS)

    Shorttle, O.; Hoggard, M.; Matthews, S.; Maclennan, J.

    2015-12-01

    Continental rifting is often associated with extensive magmatic activity, emplacing millions of cubic kilometres of basalt and triggering environmental change. The lasting geological record of this volcanic catastrophism are the large igneous provinces found at the margins of many continents and abrupt extinctions in the fossil record, most strikingly that found at the Permo-Triassic boundary. Rather than being considered purely a passive plate tectonic phenomenon, these episodes are frequently explained by the involvement of mantle plumes, upwellings of mantle rock made buoyant by their high temperatures. However, there has been debate over the relative role of the mantle's temperature and composition in generating the large volumes of magma involved in rift and intra-plate volcanism, and even when the mantle is inferred to be hot, this has been variously attributed to mantle plumes or continental insulation effects. To help resolve these uncertainties we have combined geochemical, geophysical and modelling results in a two stage approach: Firstly, we have investigated how mantle composition and temperature contribute to melting beneath Iceland, the present day manifestation of the mantle plume implicated in the 54Ma break up of the North Atlantic. By considering both the igneous crustal production on Iceland and the chemistry of its basalts we have been able to place stringent constraints on the viable temperature and lithology of the Icelandic mantle. Although a >100°C excess temperature is required to generate Iceland's thick igneous crust, geochemistry also indicates that pyroxenite comprises 10% of its source. Therefore, the dynamics of rifting on Iceland are modulated both by thermal and compositional mantle anomalies. Secondly, we have performed a global assessment of the mantle's post break-up thermal history to determine the amplitude and longevity of continental insulation in driving excess volcanism. Using seismically constrained igneous crustal

  12. Method and apparatus for controlling hybrid powertrain system in response to engine temperature

    SciTech Connect

    Martini, Ryan D; Spohn, Brian L; Lehmen, Allen J; Cerbolles, Teresa L

    2014-10-07

    A method for controlling a hybrid powertrain system including an internal combustion engine includes controlling operation of the hybrid powertrain system in response to a preferred minimum coolant temperature trajectory for the internal combustion engine.

  13. On line diagnostics and self-tuning method for the fluidized bed temperature controller

    NASA Astrophysics Data System (ADS)

    Porzuczek, Jan

    2016-03-01

    The paper presents the method of on-line diagnostics of the bed temperature controller for the fluidized bed boiler. Proposed solution is based on the methods of statistical process control. Detected decrease of the bed temperature control quality is used to activate the controller self-tuning procedure. The algorithm that provides optimal tuning of the bed temperature controller is also proposed. The results of experimental verification of the presented method is attached. Experimental studies were carried out using the 2 MW bubbling fluidized bed boiler.

  14. Temperature-stable LED-based light source without temperature control

    NASA Astrophysics Data System (ADS)

    Bosiljevac, M.; Babić, D.; Sipus, Zvonimir

    2016-03-01

    Many medical, environmental, and industrial sensing applications could take advantage of uncooled temperature-stable optical sources that are incoherent and un-polarized as such sources do not produce interference fringes, speckle patterns, or intensity variations due to polarization. For this purpose we propose an optical system for stabilization of light-emitting diodes over temperature exhibiting output power variation below 50 ppm/°C which does not employ any kind of TEC elements or even thermometers. This makes it especially suitable for handheld and battery operated instruments.

  15. Optimized Design of the SGA-WZ Strapdown Airborne Gravimeter Temperature Control System

    PubMed Central

    Cao, Juliang; Wang, Minghao; Cai, Shaokun; Zhang, Kaidong; Cong, Danni; Wu, Meiping

    2015-01-01

    The temperature control system is one of the most important subsystems of the strapdown airborne gravimeter. Because the quartz flexible accelerometer based on springy support technology is the core sensor in the strapdown airborne gravimeter and the magnet steel in the electromagnetic force equilibrium circuits of the quartz flexible accelerometer is greatly affected by temperature, in order to guarantee the temperature control precision and minimize the effect of temperature on the gravimeter, the SGA-WZ temperature control system adopts a three-level control method. Based on the design experience of the SGA-WZ-01, the SGA-WZ-02 temperature control system came out with a further optimized design. In 1st level temperature control, thermoelectric cooler is used to conquer temperature change caused by hot weather. The experiments show that the optimized stability of 1st level temperature control is about 0.1 °C and the max cool down capability is about 10 °C. The temperature field is analyzed in the 2nd and 3rd level temperature control using the finite element analysis software ANSYS. The 2nd and 3rd level temperature control optimization scheme is based on the foundation of heat analysis. The experimental results show that static accuracy of SGA-WZ-02 reaches 0.21 mGal/24 h, with internal accuracy being 0.743 mGal/4.8 km and external accuracy being 0.37 mGal/4.8 km compared with the result of the GT-2A, whose internal precision is superior to 1 mGal/4.8 km and all of them are better than those in SGA-WZ-01. PMID:26633407

  16. Optimized Design of the SGA-WZ Strapdown Airborne Gravimeter Temperature Control System.

    PubMed

    Cao, Juliang; Wang, Minghao; Cai, Shaokun; Zhang, Kaidong; Cong, Danni; Wu, Meiping

    2015-12-01

    The temperature control system is one of the most important subsystems of the strapdown airborne gravimeter. Because the quartz flexible accelerometer based on springy support technology is the core sensor in the strapdown airborne gravimeter and the magnet steel in the electromagnetic force equilibrium circuits of the quartz flexible accelerometer is greatly affected by temperature, in order to guarantee the temperature control precision and minimize the effect of temperature on the gravimeter, the SGA-WZ temperature control system adopts a three-level control method. Based on the design experience of the SGA-WZ-01, the SGA-WZ-02 temperature control system came out with a further optimized design. In 1st level temperature control, thermoelectric cooler is used to conquer temperature change caused by hot weather. The experiments show that the optimized stability of 1st level temperature control is about 0.1 °C and the max cool down capability is about 10 °C. The temperature field is analyzed in the 2nd and 3rd level temperature control using the finite element analysis software ANSYS. The 2nd and 3rd level temperature control optimization scheme is based on the foundation of heat analysis. The experimental results show that static accuracy of SGA-WZ-02 reaches 0.21 mGal/24 h, with internal accuracy being 0.743 mGal/4.8 km and external accuracy being 0.37 mGal/4.8 km compared with the result of the GT-2A, whose internal precision is superior to 1 mGal/4.8 km and all of them are better than those in SGA-WZ-01.

  17. Atmospheric CO2: Principal Control Knob Governing Earth's Temperature

    NASA Technical Reports Server (NTRS)

    Lacis, Andrew A.; Schmidt, Gavin A.; Rind, David; Ruedy, Reto A.

    2010-01-01

    Ample physical evidence shows that carbon dioxide (CO2) is the single most important climate-relevant greenhouse gas in Earth s atmosphere. This is because CO2, like ozone, N2O, CH4, and chlorofluorocarbons, does not condense and precipitate from the atmosphere at current climate temperatures, whereas water vapor can and does. Noncondensing greenhouse gases, which account for 25% of the total terrestrial greenhouse effect, thus serve to provide the stable temperature structure that sustains the current levels of atmospheric water vapor and clouds via feedback processes that account for the remaining 75% of the greenhouse effect. Without the radiative forcing supplied by CO2 and the other noncondensing greenhouse gases, the terrestrial greenhouse would collapse, plunging the global climate into an icebound Earth state.

  18. Development of a prototype automatic controller for liquid cooling garment inlet temperature

    NASA Technical Reports Server (NTRS)

    Weaver, C. S.; Webbon, B. W.; Montgomery, L. D.

    1982-01-01

    The development of a computer control of a liquid cooled garment (LCG) inlet temperature is descirbed. An adaptive model of the LCG is used to predict the heat-removal rates for various inlet temperatures. An experimental system that contains a microcomputer was constructed. The LCG inlet and outlet temperatures and the heat exchanger outlet temperature form the inputs to the computer. The adaptive model prediction method of control is successful during tests where the inlet temperature is automatically chosen by the computer. It is concluded that the program can be implemented in a microprocessor of a size that is practical for a life support back-pack.

  19. Coolant and ambient temperature control for chillerless liquid cooled data centers

    DOEpatents

    Chainer, Timothy J.; David, Milnes P.; Iyengar, Madhusudan K.; Parida, Pritish R.; Simons, Robert E.

    2016-02-02

    Cooling control methods include measuring a temperature of air provided to a plurality of nodes by an air-to-liquid heat exchanger, measuring a temperature of at least one component of the plurality of nodes and finding a maximum component temperature across all such nodes, comparing the maximum component temperature to a first and second component threshold and comparing the air temperature to a first and second air threshold, and controlling a proportion of coolant flow and a coolant flow rate to the air-to-liquid heat exchanger and the plurality of nodes based on the comparisons.

  20. Method of controlling temperature of a thermoelectric generator in an exhaust system

    DOEpatents

    Prior, Gregory P; Reynolds, Michael G; Cowgill, Joshua D

    2013-05-21

    A method of controlling the temperature of a thermoelectric generator (TEG) in an exhaust system of an engine is provided. The method includes determining the temperature of the heated side of the TEG, determining exhaust gas flow rate through the TEG, and determining the exhaust gas temperature through the TEG. A rate of change in temperature of the heated side of the TEG is predicted based on the determined temperature, the determined exhaust gas flow rate, and the determined exhaust gas temperature through the TEG. Using the predicted rate of change of temperature of the heated side, exhaust gas flow rate through the TEG is calculated that will result in a maximum temperature of the heated side of the TEG less than a predetermined critical temperature given the predicted rate of change in temperature of the heated side of the TEG. A corresponding apparatus is provided.

  1. Temperature sensing by an olfactory neuron in a circuit controlling behavior of C. elegans.

    PubMed

    Kuhara, Atsushi; Okumura, Masatoshi; Kimata, Tsubasa; Tanizawa, Yoshinori; Takano, Ryo; Kimura, Koutarou D; Inada, Hitoshi; Matsumoto, Kunihiro; Mori, Ikue

    2008-05-09

    Temperature is an unavoidable environmental cue that affects the metabolism and behavior of any creature on Earth, yet how animals perceive temperature is poorly understood. The nematode Caenorhabditis elegans "memorizes" temperatures, and this stored information modifies its subsequent migration along a temperature gradient. We show that the olfactory neuron designated AWC senses temperature. Calcium imaging revealed that AWC responds to temperature changes and that response thresholds differ depending on the temperature to which the animal was previously exposed. In the mutant with impaired heterotrimeric guanine nucleotide-binding protein (G protein)-mediated signaling, AWC was hyperresponsive to temperature, whereas the AIY interneuron (which is postsynaptic to AWC) was hyporesponsive to temperature. Thus, temperature sensation exhibits a robust influence on a neural circuit controlling a memory-regulated behavior.

  2. Skin temperature as a thermal controller of exercise intensity.

    PubMed

    Schlader, Zachary J; Simmons, Shona E; Stannard, Stephen R; Mündel, Toby

    2011-08-01

    This study examined the role of skin temperature on self-selected exercise intensity (i.e., power output). Eight well-trained, male cyclists completed two 60 min self-paced cycling bouts during which they completed as much work as possible. Using a liquid-perfused suit, skin temperature (T (Sk)) was changed during the two trials such that T (Sk) either started hot and was cooled (H to C) or started cold and was heated (C to H) throughout exercise. Pre-exercise core temperatures (T (C)) and heart rates (HR) were similar between trials, while T (Sk), thermal comfort and thermal sensation were higher in H to C. The change in T (Sk) was similar in magnitude during the two trials. Work completed was greatest in C to H, which was attributed to a higher initial power output. T (C) was similar between trials. HR was similar until 35 min had elapsed, after which it became lower in H to C. The perception of effort increased similarly between the two trials, while thermal comfort and thermal sensation generally reflected the changes observed in T (Sk). These results indicate that upon exercise commencement T (Sk) and the accompanying thermal perceptions are important inputs in the initial selection of exercise intensity.

  3. Lay out, test verification and in orbit performance of HELIOS a temperature control system

    NASA Technical Reports Server (NTRS)

    Brungs, W.

    1975-01-01

    HELIOS temperature control system is described. The main design features and the impact of interactions between experiment, spacecraft system, and temperature control system requirements on the design are discussed. The major limitations of the thermal design regarding a closer sun approach are given and related to test experience and performance data obtained in orbit. Finally the validity of the test results achieved with prototype and flight spacecraft is evaluated by comparison between test data, orbit temperature predictions and flight data.

  4. Controls on cave drip water temperature and implications for speleothem-based paleoclimate reconstructions

    NASA Astrophysics Data System (ADS)

    Rau, Gabriel C.; Cuthbert, Mark O.; Andersen, Martin S.; Baker, Andy; Rutlidge, Helen; Markowska, Monika; Roshan, Hamid; Marjo, Christopher E.; Graham, Peter W.; Acworth, R. Ian

    2015-11-01

    While several studies explore cave climate and thermal regimes, little is known about the controls on cave drip water temperature. Yet water temperature significantly influences biogeochemical processes associated with cave drips. To identify the processes that control the cave drip water temperature, we measured the temperatures at multiple locations along a speleothem flow path and drip sources (stalactites) concurrently with the drip rates in Cathedral Cave, Wellington, Australia. We monitored long-term drip water temperature, drip rates, surface and cave climate and in-cave evaporation rates and conducted 3 infiltration experiments with different flow, temperature and isotopic conditions. Our results show that the drip water temperature is controlled by multiple superimposed heat transport mechanisms that act upon the infiltrating water in the epikarst, the water film after it enters the cave and before it becomes a drip. The two main heat sources/sinks for drip water are the cave air and the surrounding rock. The subsurface temperature is coupled to the surface temperature by conduction through the soil and rock mass, but the cave climate is also coupled to the surface climate by venting. On a regional scale, drip temperatures are mainly driven by the annual ground surface temperature signal but damped with depth and shifted in time compared to the surface. On a local scale, the drip water temperature can differ significantly from cave air and speleothem temperature due to the latent heat exchange of evaporation and localised water film convection. The main controls are ground surface temperature, subsurface depth, air density induced ventilation, distance from entry and drip rate. We present a conceptual model that explains drip water temperature signals and provide signal driven guidance on best type and location for speleothem sampling. We anticipate that our results will significantly improve the understanding of temperature-dependent paleoclimate signals

  5. Factors Controlling Elevated Temperature Strength Degradation of Silicon Carbide Composites

    NASA Technical Reports Server (NTRS)

    2005-01-01

    For 5 years, the cooperative agreement NCC3-763 has focused on the development and understanding of Sic-based composites. Most of the work was performed in the area of SiC fiber-reinforced composites for UEET and NGLT and in collaboration with Goodrich Corporation under a partially reimbursable Space Act Agreement. A smaller amount of work was performed on C fiber-reinforced SiC matrix composites for NGLT. Major accomplishments during this agreement included: Improvements to the interphase used in melt-infiltrated (MI) SiC/SiC composites which increases the life under stressed-oxidation at intermediate temperatures referred to as "outside-debonding". This concept is currently in the patent process and received a Space Act Award. Mechanistic-based models of intermediate temperature degradation for MI SiC/SiC Quantification and relatively robust relationships for matrix crack evolution under stress in SiC/SiC composites which serve as the basis for stress-strain and elevated temperature life models The furthering of acoustic emission as a useful tool in composite damage evolution and the extension of the technique to other composite systems Development of hybrid C-SiC fiber-reinforced SiC matrix composites Numerous presentations at conferences, industry partners, and government centers and publications in recognized proceedings and journals. Other recognition of the author's accomplishments by NASA with a TGIR award (2004), NASA's Medal for Public Service (2004), and The American Ceramic Society s Richard M. Fulrath Award (2005). The following will briefly describe the work of the past five years in the three areas of interest: SiC/SiC composite development, mechanistic understanding and modeling of SiC/SiC composites, and environmental durability of C/SiC composites. More detail can be found in the publications cited at the end of this report.

  6. Multichannel temperature controller for hot air solar house

    NASA Technical Reports Server (NTRS)

    Currie, J. R.

    1979-01-01

    This paper describes an electronic controller that is optimized to operate a hot air solar system. Thermal information is obtained from copper constantan thermocouples and a wall-type thermostat. The signals from the thermocouples are processed through a single amplifier using a multiplexing scheme. The multiplexing reduces the component count and automatically calibrates the thermocouple amplifier. The processed signals connect to some simple logic that selects one of the four operating modes. This simple, inexpensive, and reliable scheme is well suited to control hot air solar systems.

  7. Pulse width modulation-based temperature tracking for feedback control of a shape memory alloy actuator.

    PubMed

    Ayvali, Elif; Desai, Jaydev P

    2014-04-01

    This work presents a temperature-feedback approach to control the radius of curvature of an arc-shaped shape memory alloy (SMA) wire. The nonlinear properties of the SMA such as phase transformation and its dependence on temperature and stress make SMA actuators difficult to control. Tracking a desired trajectory is more challenging than controlling just the position of the SMA actuator since the desired path is continuously changing. Consequently, tracking the desired strain directly or tracking the parameters such as temperature and electrical resistance that are related to strain with a model is a challenging task. Temperature-feedback is an attractive approach when direct measurement of strain is not practical. Pulse width modulation (PWM) is an effective method for SMA actuation and it can be used along with a compensator to control the temperature of the SMA. Using the constitutive model of the SMA, the desired temperature profile can be obtained for a given strain trajectory. A PWM-based nonlinear PID controller with a feed-forward heat transfer model is proposed to use temperature-feedback for tracking a desired temperature trajectory. The proposed controller is used during the heating phase of the SMA actuator. The controller proves to be effective in tracking step-wise and continuous trajectories.

  8. Takagi-Sugeno control of nocturnal temperature in greenhouses using air heating.

    PubMed

    Nachidi, M; Rodríguez, F; Tadeo, F; Guzman, J L

    2011-04-01

    A solution to the problem of controlling the minimum temperature in greenhouses using controllers developed from nonlinear models of the system is discussed and applied on a real greenhouse. More precisely, the controllers designed are Takagi-Sugeno type controllers, and the proposed design method is an iterative method based on solving a set of Linear Matrix Inequalities, which ensures stability and performance in closed-loop. The tests in a real greenhouse show that it is possible to design controllers for control of nocturnal temperature that give good performance, and guarantee stability in a wide range of working conditions.

  9. Understanding and controlling low-temperature aging of nanocrystalline materials.

    SciTech Connect

    Battaile, Corbett Chandler; Boyce, Brad Lee; Brons, Justin G.; Foiles, Stephen Martin; Hattar, Khalid Mikhiel; Holm, Elizabeth A; Padilla, Henry A.,; Sharon, John Anthony; Thompson, Gregory B.

    2013-10-01

    Nanocrystalline copper lms were created by both repetitive high-energy pulsed power, to produce material without internal nanotwins; and pulsed laser deposition, to produce nan- otwins. Samples of these lms were indented at ambient (298K) and cryogenic temperatures by immersion in liquid nitrogen (77K) and helium (4K). The indented samples were sectioned through the indented regions and imaged in a scanning electron microscope. Extensive grain growth was observed in the lms that contained nanotwins and were indented cryogenically. The lms that either lacked twins, or were indented under ambient conditions, were found to exhibit no substantial grain growth by visual inspection. Precession transmission elec- tron microscopy was used to con rm these ndings quantitatively, and show that 3 and 7 boundaries proliferate during grain growth, implying that these interface types play a key role in governing the extensive grain growth observed here. Molecular dynamics sim- ulations of the motion of individual grain boundaries demonstrate that speci c classes of boundaries - notably 3 and 7 - exhibit anti- or a-thermal migration, meaning that their mobilities either increase or do not change signi cantly with decreasing temperature. An in-situ cryogenic indentation capability was developed and implemented in a transmission electron microscope. Preliminary results do not show extensive cryogenic grain growth in indented copper lms. This discrepancy could arise from the signi cant di erences in con g- uration and loading of the specimen between the two approaches, and further research and development of this capability is needed.

  10. Temperature controls organic carbon sequestration in a subarctic lake

    NASA Astrophysics Data System (ADS)

    Rantala, Marttiina V.; Luoto, Tomi P.; Nevalainen, Liisa

    2016-10-01

    Widespread ecological reorganizations and increases in organic carbon (OC) in lakes across the Northern Hemisphere have raised concerns about the impact of the ongoing climate warming on aquatic ecosystems and carbon cycling. We employed diverse biogeochemical techniques on a high-resolution sediment record from a subarctic lake in northern Finland (70°N) to examine the direction, magnitude and mechanism of change in aquatic carbon pools prior to and under the anthropogenic warming. Coupled variation in the elemental and isotopic composition of the sediment and a proxy-based summer air temperature reconstruction tracked changes in aquatic production, depicting a decline during a cool climate interval between ~1700–1900 C.E. and a subsequent increase over the 20th century. OC accumulation rates displayed similar coeval variation with temperature, mirroring both changes in aquatic production and terrestrial carbon export. Increase in sediment organic content over the 20th century together with high inferred aquatic UV exposure imply that the 20th century increase in OC accumulation is primarily connected to elevated lake production rather than terrestrial inputs. The changes in the supply of autochthonous energy sources were further reflected higher up the benthic food web, as evidenced by biotic stable isotopic fingerprints.

  11. Temperature controls organic carbon sequestration in a subarctic lake

    PubMed Central

    Rantala, Marttiina V.; Luoto, Tomi P.; Nevalainen, Liisa

    2016-01-01

    Widespread ecological reorganizations and increases in organic carbon (OC) in lakes across the Northern Hemisphere have raised concerns about the impact of the ongoing climate warming on aquatic ecosystems and carbon cycling. We employed diverse biogeochemical techniques on a high-resolution sediment record from a subarctic lake in northern Finland (70°N) to examine the direction, magnitude and mechanism of change in aquatic carbon pools prior to and under the anthropogenic warming. Coupled variation in the elemental and isotopic composition of the sediment and a proxy-based summer air temperature reconstruction tracked changes in aquatic production, depicting a decline during a cool climate interval between ~1700–1900 C.E. and a subsequent increase over the 20th century. OC accumulation rates displayed similar coeval variation with temperature, mirroring both changes in aquatic production and terrestrial carbon export. Increase in sediment organic content over the 20th century together with high inferred aquatic UV exposure imply that the 20th century increase in OC accumulation is primarily connected to elevated lake production rather than terrestrial inputs. The changes in the supply of autochthonous energy sources were further reflected higher up the benthic food web, as evidenced by biotic stable isotopic fingerprints. PMID:27708382

  12. Selection and Validation of Reference Genes for Accurate RT-qPCR Data Normalization in Coffea spp. under a Climate Changes Context of Interacting Elevated [CO2] and Temperature

    PubMed Central

    Martins, Madlles Q.; Fortunato, Ana S.; Rodrigues, Weverton P.; Partelli, Fábio L.; Campostrini, Eliemar; Lidon, Fernando C.; DaMatta, Fábio M.; Ramalho, José C.; Ribeiro-Barros, Ana I.

    2017-01-01

    World coffee production has faced increasing challenges associated with ongoing climatic changes. Several studies, which have been almost exclusively based on temperature increase, have predicted extensive reductions (higher than half by 2,050) of actual coffee cropped areas. However, recent studies showed that elevated [CO2] can strongly mitigate the negative impacts of heat stress at the physiological and biochemical levels in coffee leaves. In addition, it has also been shown that coffee genotypes can successfully cope with temperatures above what has been traditionally accepted. Altogether, this information suggests that the real impact of climate changes on coffee growth and production could be significantly lower than previously estimated. Gene expression studies are an important tool to unravel crop acclimation ability, demanding the use of adequate reference genes. We have examined the transcript stability of 10 candidate reference genes to normalize RT-qPCR expression studies using a set of 24 cDNAs from leaves of three coffee genotypes (CL153, Icatu, and IPR108), grown under 380 or 700 μL CO2 L−1, and submitted to increasing temperatures from 25/20°C (day/night) to 42/34°C. Samples were analyzed according to genotype, [CO2], temperature, multiple stress interaction ([CO2], temperature) and total stress interaction (genotype, [CO2], and temperature). The transcript stability of each gene was assessed through a multiple analytical approach combining the Coeficient of Variation method and three algorithms (geNorm, BestKeeper, NormFinder). The transcript stability varied according to the type of stress for most genes, but the consensus ranking obtained with RefFinder, classified MDH as the gene with the highest mRNA stability to a global use, followed by ACT and S15, whereas α-TUB and CYCL showed the least stable mRNA contents. Using the coffee expression profiles of the gene encoding the large-subunit of ribulose-1,5-bisphosphate carboxylase

  13. Materials Processing and Microstructure Control in High Temperature Ordered Intermetallics.

    DTIC Science & Technology

    2007-11-02

    an integrated approach that couples processing with microstructure control as guided by the operative phase equilibria has been used to identify...several promising intermetallic alloys. The experimental efforts have focused on three areas involving a coordination of phase equilibria information with

  14. Temperature dynamics and control of a water-cooled fuel cell stack

    NASA Astrophysics Data System (ADS)

    O'Keefe, Daniel; El-Sharkh, M. Y.; Telotte, John C.; Palanki, Srinivas

    2014-06-01

    In this paper, a time-varying proportional-integral (PI) controller is designed for controlling the temperature of a water-cooled 5 kW hydrogen fuel cell stack. This controller is designed using a mathematical model for the stack temperature, which is derived using basic chemical engineering material and energy balances. The controller affects the stack temperature by changing the flow rate of cooling water that passes across the stack. The model is then analyzed using a number of power demand profiles to determine the effectiveness of the controller. The results show that a time-varying PI controller is adequate for maintaining the stack temperature within 5 K of the target point.

  15. Organic thermoelectric materials for energy harvesting and temperature control

    NASA Astrophysics Data System (ADS)

    Russ, Boris; Glaudell, Anne; Urban, Jeffrey J.; Chabinyc, Michael L.; Segalman, Rachel A.

    2016-10-01

    Conjugated polymers and related processing techniques have been developed for organic electronic devices ranging from lightweight photovoltaics to flexible displays. These breakthroughs have recently been used to create organic thermoelectric materials, which have potential for wearable heating and cooling devices, and near-room-temperature energy generation. So far, the best thermoelectric materials have been inorganic compounds (such as Bi2Te3) that have relatively low Earth abundance and are fabricated through highly complex vacuum processing routes. Molecular materials and hybrid organic-inorganic materials now demonstrate figures of merit approaching those of these inorganic materials, while also exhibiting unique transport behaviours that are suggestive of optimization pathways and device geometries that were not previously possible. In this Review, we discuss recent breakthroughs for organic materials with high thermoelectric figures of merit and indicate how these materials may be incorporated into new module designs that take advantage of their mechanical and thermoelectric properties.

  16. Infrared Astronomical Satellite (IRAS) superfluid helium tank temperature control

    NASA Technical Reports Server (NTRS)

    Petrac, D.; Mason, P. V.

    1984-01-01

    The infrared detectors on the Infrared Astronomical Satellite (IRAS), which was placed into a polar orbit in January 1983, are cooled to a temperature of less than 3 K by thermal coupling to the main cryogenic tank (MCT) containing superfluid helium. A porous plug built into the vent line entrance acts as a superfluid helium liquid/vapor separator in zero gravity. A description of the IRAS MCT flight porous plug is presented, and tests of the plug in situ are discussed, taking into account submerged plug tests, a restart test, and a cold vapor flow test. Aspects of flow rate determination in the case of an unavailability of flight flow rate data are also considered.

  17. Temperature controlled junction behavior of polyaniline/ZnO heterostructures

    NASA Astrophysics Data System (ADS)

    Dhingra, Mansi; Shrivastava, Sadhna; Asokan, K.; Annapoorni, S.

    2016-05-01

    Organic-Inorganic hybrid materials have remained an active field of research both from the point of understanding the interfaces and for device purpose. In the present work, Zinc Oxide (ZnO) - Polyaniline (PANI) interface obtained by drop casting PANI nanofibres on sputtered ZnO thin film is investigated. The study of layer by layer deposition of organic and inorganic materials to form interface, is a very important issue related to carrier transport, charge separation, structural connectivity and interfacial defects. I-V characteristics were performed for different thickness of the underlying ZnO layer. The effect of temperature on the I-V characteristics is also investigated. Hall measurements were performed to estimate the charge carrier concentration of the n-ZnO and the p-PANI. Morphology and thickness of the interface was studied using SEM imaging technique. These interfaces could be explored for different applications in areas like sensors and optoelectronics.

  18. Heat pipes for spacecraft temperature control: An assessment of the state-of-the-art

    NASA Technical Reports Server (NTRS)

    Kirkpatrick, J. P.; Groll, M.

    1976-01-01

    Various heat pipe temperature control techniques are critically evaluated using characteristic features and properties, including heat transport capability, volume and mass requirements, complexity and ease of fabrication, reliability, and control characteristics. Advantages and disadvantages of specific approaches are derived and discussed. Using four development levels, the state of-the-art of the various heat pipe temperature control techniques is assessed. The need for further research and development is discussed and suggested future efforts are projected.

  19. 12-Channel Peltier array temperature control unit for single molecule enzymology studies using capillary electrophoresis.

    PubMed

    Craig, Douglas B; Reinfelds, Gundars; Henderson, Anna

    2014-08-01

    Capillary electrophoresis has been used to demonstrate that individual molecules of a given enzyme support different catalytic rates. In order to determine how rate varies with temperature, and determine activation energies for individual β-galactosidase molecules, a 12-channel Peltier array temperature control device was constructed where the temperature of each cell was separately controlled. This array was used to control the temperature of the central 30 cm of a 50 cm long capillary, producing a temperature gradient along its length. Continuous flow single β-galactosidase molecule assays were performed allowing measurement of the catalytic rates at different temperatures. Arrhenius plots were produced and the distribution of activation energies for individual β-galactosidase molecules was found to be 56 ± 10 kJ/mol with a range of 34-72 kJ/mol.

  20. Reducing temperature influence on dry quantitative ultrasound bone assessment with constant temperature control.

    PubMed

    Chen, Yan-Yan; Xu, Yu-Bing; Zhan, Li-Kui; Ma, Zu-Chang; Sun, Yi-Ning

    2012-02-01

    Nowadays, ultrasonic bone assessment is increasingly being used to assess bone status. Therefore, the purpose of this study was to enhance the precision of ultrasonic bone assessment by reducing the influence of temperature in a dry, gel coupled transducer system. A warm airflow generator was designed to make the measurement temperature constant (35±1°C). Thirty people were recruited for the evaluation of in-vivo performance. The short-term precision was performed 10 times with repositioning during a consecutive measurement session within 20min. It was expressed as root-mean square average of coefficient of variation, which is abbreviated for CV(RMS). The CV(RMS) was 3.84% for broadband ultrasound attenuation, and 0.30% for speed of sound. The Pearson correlations between gel coupled transducer system and dual energy X-ray absorptiometry (DEXA) were 0.808 (p<0.001) for broadband ultrasound attenuation, and 0.586 (p<0.005) for speed of sound. The result showed the high performance of reproducibility and the significant (p<0.005) correlations with DEXA in the dry, gel coupled transducer system.

  1. Low-temperature solution syntheses of hexagonal ZnO nanorods and morphology-controlled nanostructures

    NASA Astrophysics Data System (ADS)

    Son, Nguyen Thanh; Noh, Jin-Seo; Lee, In-Hwan

    2016-02-01

    Well-developed hexagonal ZnO nanorods and morphology-controlled nanostructures were synthesized at low temperatures using a simple solution method without the assistance of any templates or catalysts. Uniform conical nanorods with an average diameter of 35 nm and the aspect ratio of 14 could be obtained at a near-room temperature, while nanoplatelets with the planar aspect ratio of 2.4-4.8 were produced at higher temperatures. It was revealed that the morphology, dimensions, and the crystallinity of ZnO nanostructures could be controlled by elaborately adjusting experimental conditions such as the molar ratio of Zn2+ to OH-, EDA concentration, and temperature.

  2. An active thermal control surfaces experiment. [spacecraft temperature determination

    NASA Technical Reports Server (NTRS)

    Wilkes, D. R.; Brown, M. J.

    1979-01-01

    An active flight experiment is described that has the objectives to determine the effects of the low earth natural environment and the Shuttle induced environment on selected thermal control and optical surfaces. The optical and thermal properties of test samples will be measured in-situ using an integrating sphere reflectrometer and using calorimetric methods. This experiment has been selected for the Long Duration Exposure Facility (LDEF) flight which will be carried to orbit by the NASA Space Shuttle. The LDEF will remain in orbit to be picked up by a later Shuttle mission and returned for postflight evaluation.

  3. Jasmonates: Emerging Players in Controlling Temperature Stress Tolerance.

    PubMed

    Sharma, Manvi; Laxmi, Ashverya

    2015-01-01

    The sedentary life of plants has forced them to live in an environment that is characterized by the presence of numerous challenges in terms of biotic and abiotic stresses. Phytohormones play essential roles in mediating plant physiology and alleviating various environmental perturbations. Jasmonates are a group of oxylipin compounds occurring ubiquitously in the plant kingdom that play pivotal roles in response to developmental and environmental cues. Jasmonates (JAs) have been shown to participate in unison with key factors of other signal transduction pathway, including those involved in response to abiotic stress. Recent findings have furnished large body of information suggesting the role of jasmonates in cold and heat stress. JAs have been shown to regulate C-repeat binding factor (CBF) pathway during cold stress. The interaction between the integrants of JA signaling and components of CBF pathway demonstrates a complex relationship between the two. JAs have also been shown to counteract chilling stress by inducing ROS avoidance enzymes. In addition, several lines of evidence suggest the positive regulation of thermotolerance by JA. The present review provides insights into biosynthesis, signal transduction pathway of jasmonic acid and their role in response to temperature stress.

  4. Jasmonates: Emerging Players in Controlling Temperature Stress Tolerance

    PubMed Central

    Sharma, Manvi; Laxmi, Ashverya

    2016-01-01

    The sedentary life of plants has forced them to live in an environment that is characterized by the presence of numerous challenges in terms of biotic and abiotic stresses. Phytohormones play essential roles in mediating plant physiology and alleviating various environmental perturbations. Jasmonates are a group of oxylipin compounds occurring ubiquitously in the plant kingdom that play pivotal roles in response to developmental and environmental cues. Jasmonates (JAs) have been shown to participate in unison with key factors of other signal transduction pathway, including those involved in response to abiotic stress. Recent findings have furnished large body of information suggesting the role of jasmonates in cold and heat stress. JAs have been shown to regulate C-repeat binding factor (CBF) pathway during cold stress. The interaction between the integrants of JA signaling and components of CBF pathway demonstrates a complex relationship between the two. JAs have also been shown to counteract chilling stress by inducing ROS avoidance enzymes. In addition, several lines of evidence suggest the positive regulation of thermotolerance by JA. The present review provides insights into biosynthesis, signal transduction pathway of jasmonic acid and their role in response to temperature stress. PMID:26779205

  5. Temperature control for PCR thermocyclers based on peltier-effect thermoelectric.

    PubMed

    Qiu, Xianbo; Yuan, Jingqi

    2005-01-01

    In thermal cycling of polymerase chain reaction, the process recipe is characterized by high ramp rates and short temperature holds. In order to reduce the time taken to complete a standard PCR protocol, a model-based hybrid control configuration is designed to rapidly track the thermal cycling recipe. The hybrid control configuration consists of feedforward, feedback and Bang-Bang actions, of which, the feedforward control is a model predictive control action and improves the dynamic performance of temperature tracking significantly. The model of the thermocycler is identified with step response data at different operating regions. Experimental results demonstrate that the hybrid control strategy performs better than the conventional PID controller both in setpoint response and in steady-state performance of temperature control, so that the accuracy and efficiency of PCR are improved accordingly.

  6. Analysis, testing, and control of telescope's high-precision drive system in low-temperature environment

    NASA Astrophysics Data System (ADS)

    Du, Fu-Jia; Zhang, Jian; Wen, Hai-Kun

    2014-07-01

    Antarctic is perfect site for astronomic observatory. But Antarctic also challenge the telescope design because of low temperature. The low temperature can impact characterization of telescope control system, especially for drive system. The following phenomenon can be produced due to low temperature. 1. The viscosity of grease will increase. 2. The clearance of bearing and gear will decrease. These two factors can lead to the increase in load torque of drive system with temperature drop. This would cause the bad tracking accuracy and low speed creeping. In order to overcome the impact of low temperature and improve the telescope's track accuracy. In this paper, we describe some methods to overcome the effect of low temperature. First, the motor's electromagnetism and lubrication in low temperature are analyzed. It shows that motor's electromagnetism is little affected by temperature if the suitable material is selected. But the characterization of grease change dramatically with temperature. Second, the other lubricant material, solid lubricant, instead of lubricating grease is proposed. Contrasting experiment on two lubricant material proved that the solid lubricant is better than lubricating grease in low temperature environment. Third, besides the mechanical solution, a method from control point view is proposed to reduce the temperature influence. In this paper, the friction feedforward algorithm is used to compensate the torque change. Laboratory testing results will be presented verifying that friction feedforward can increase the tracking accuracy in low temperature environment.

  7. An alternate method for achieving temperature control in the -130 C to 75 C range

    NASA Technical Reports Server (NTRS)

    Johnson, Kenneth R.; Anderson, Mark R.; Lane, Robert W.; Cortez, Maximo G.

    1992-01-01

    Thermal vacuum testing often requires temperature control of chamber shrouds and heat exchangers within the -130 C to 75 C range. There are two conventional methods which are normally employed to achieve control through this intermediate temperature range: (1) single-pass flow where control is achieved by alternately pulsing hot gaseous nitrogen (GN2) and cold LN2 into the feed line to yield the setpoint temperature; and (2) closed-loop circulation where control is achieved by either electrically heating or LN2 cooling the circulating GN2 to yield the setpoint temperature. A third method, using a mass flow ratio controller along with modulating control valves on GN2 and LN2 lines, provides excellent control but equipment for this method is expensive and cost-prohibitive for all but long-term continuous processes. The single-pass method provides marginal control and can result in unexpected overcooling of the test article from even a short pulse of LN2. The closed-loop circulation method provides excellent control but requires an expensive blower capable of operating at elevated pressures and cryogenic temperatures. Where precise control is needed (plus or minus 2 C), single-pass flow systems typically have not provided the precision required, primarily because of overcooling temperature excursions. Where several individual circuits are to be controlled at different temperatures, the use of expensive cryogenic blowers for each circuit is also cost-prohibitive, especially for short duration of one-of-a-kind tests. At JPL, a variant of the single-pass method was developed that was shown to provide precise temperature control in the -130 C to 75 C range while exhibiting minimal setpoint overshoot during temperature transitions. This alternate method uses a commercially available temperature controller along with a GN2/LN2 mixer to dampen the amplitude of cold temperature spikes caused by LN2 pulsing. The design of the GN2/LN2 mixer, the overall control system

  8. Improving arachidonic acid fermentation by Mortierella alpina through multistage temperature and aeration rate control in bioreactor.

    PubMed

    Gao, Min-Jie; Wang, Cheng; Zheng, Zhi-Yong; Zhu, Li; Zhan, Xiao-Bei; Lin, Chi-Chung

    2016-05-18

    Effective production of arachidonic acid (ARA) using Mortierella alpina was conducted in a 30-L airlift bioreactor. Varying the aeration rate and temperature significantly influenced cell morphology, cell growth, and ARA production, while the optimal aeration rate and temperature for cell growth and product formation were quite different. As a result, a two-stage aeration rate control strategy was constructed based on monitoring of cell morphology and ARA production under various aeration rate control levels (0.6-1.8 vvm). Using this strategy, ARA yield reached 4.7 g/L, an increase of 38.2% compared with the control (constant aeration rate control at 1.0 vvm). Dynamic temperature-control strategy was implemented based on the fermentation performance at various temperatures (13-28°C), with ARA level in total cellular lipid increased by 37.1% comparing to a constant-temperature control (25°C). On that basis, the combinatorial fermentation strategy of two-stage aeration rate control and dynamic temperature control was applied and ARA production achieved the highest level of 5.8 g/L.

  9. Synchronous temperature rate control and apparatus for refrigeration with reduced energy consumption

    DOEpatents

    Gomes, Alberto Regio; Keres, Stephen L.; Kuehl, Steven J.; Litch, Andrew D.; Richmond, Peter J.; Wu, Guolian

    2015-09-22

    A refrigerator appliance configuration, and associated methods of operation, for an appliance with a controller, a condenser, at least one evaporator, a compressor, and two refrigeration compartments. The configuration may be equipped with a variable-speed or variable-capacity compressor, variable speed evaporator or compartment fans, a damper, and/or a dual-temperature evaporator with a valve system to control flow of refrigerant through one or more pressure reduction devices. The controller, by operation of the compressor, fans, damper and/or valve system, depending on the appliance configuration, synchronizes alternating cycles of cooling each compartment to a temperature approximately equal to the compartment set point temperature.

  10. Evaluation of extreme temperature events in northern Spain based on process control charts

    NASA Astrophysics Data System (ADS)

    Villeta, M.; Valencia, J. L.; Saá, A.; Tarquis, A. M.

    2017-02-01

    Extreme climate events have recently attracted the attention of a growing number of researchers because these events impose a large cost on agriculture and associated insurance planning. This study focuses on extreme temperature events and proposes a new method for their evaluation based on statistical process control tools, which are unusual in climate studies. A series of minimum and maximum daily temperatures for 12 geographical areas of a Spanish region between 1931 and 2009 were evaluated by applying statistical process control charts to statistically test whether evidence existed for an increase or a decrease of extreme temperature events. Specification limits were determined for each geographical area and used to define four types of extreme anomalies: lower and upper extremes for the minimum and maximum anomalies. A new binomial Markov extended process that considers the autocorrelation between extreme temperature events was generated for each geographical area and extreme anomaly type to establish the attribute control charts for the annual fraction of extreme days and to monitor the occurrence of annual extreme days. This method was used to assess the significance of changes and trends of extreme temperature events in the analysed region. The results demonstrate the effectiveness of an attribute control chart for evaluating extreme temperature events. For example, the evaluation of extreme maximum temperature events using the proposed statistical process control charts was consistent with the evidence of an increase in maximum temperatures during the last decades of the last century.

  11. Diurnal evolution of the temperature sensitivity of CO2 efflux in permafrost soils under control and warm conditions.

    PubMed

    Fouché, Julien; Keller, Catherine; Allard, Michel; Ambrosi, Jean Paul

    2017-03-01

    Cryosols contain ~33% of the global soil organic carbon. Cryosol warming and permafrost degradation may enhance the CO2 release to the atmosphere through the microbial decomposition. Despite the large carbon pool, the permafrost carbon feedback on the climate remains uncertain. In this study, we aimed at better understanding the diurnal evolution of the temperature sensitivity of CO2 efflux in Cryosols. A Histic Cryosol and a Turbic Cryosol were instrumented in tussock tundra ecosystems near Salluit (Nunavik, Canada). Open top chambers were installed during summer 2011 and the ground temperature, the soil moisture and meteorological variables were recorded hourly while the ecosystem respiration was measured three times per day every second day with opaque and closed dynamic chambers in control and warm stations. Despite warmer conditions, the average CO2 efflux at the control stations at the Histic site (1.29±0.45μmolCO2m(-2)s(-1)) was lower than at the Turbic site (2.30±0.74μmolCO2m(-2)s(-1)). The increase in CO2 efflux with warming was greater in the Histic Cryosol (~39%) than in the Turbic Cryosol (~16%). Our study showed that the temperature sensitivity of the ecosystem respiration evolved during the day and decreased with the experimental warming. Both sites exhibited diurnal hysteresis loops between CO2 efflux and the soil surface temperature. The width of hysteresis loops increased with the solar radiation and decreased along the growing season. We developed simple linear models that took into account the diurnal evolution of the temperature sensitivity of CO2 efflux and we estimated the seasonal cumulative carbon release to the atmosphere. The calculation using solely diurnal measurements significantly differed from the seasonal carbon release modelled hourly. Our study highlighted that the time of the day when measurements are performed should be taken into account to accurately estimate the seasonal carbon release from tundra ecosystems.

  12. Winter to Spring Transition in Europe 48-45 degrees N: From Temperature Control by Advection to Control by Insolation

    NASA Technical Reports Server (NTRS)

    Otterman, J.; Ardizzone, J.; Atlas, R.; Hu, H.; Jusem, J. C.; Starr, D.

    1999-01-01

    As established in previous studies, and analyzed further herein for the years 1988-1998, warm advection from the North Atlantic is the predominant control of the surface-air temperature in northern-latitude Europe in late winter. This thesis is supported by the substantial correlation Cti between the speed of the southwesterly surface winds over the eastern North Atlantic, as quantified by a specific Index Ina, and the 2-meter level temperature Ts over central Europe (48-54 deg N; 5-25 deg E), for January, February and early March. In mid-March and subsequently, the correlation Cti drops drastically (quite often it is negative). The change in the relationship between Ts and Ina marks a transition in the control of the surface-air temperature. As (a) the sun rises higher in the sky, (b) the snows melt (the surface absorptivity can increase by a factor of 3.0), (c) the ocean-surface winds weaken, and (d) the temperature difference between land and ocean (which we analyze) becomes small, absorption of insolation replaces the warm advection as the dominant control of the continental temperature. We define the onset of spring by this transition, which evaluated for the period of our study occurs at pentad 16 (Julian Date 76, that is, March 16). The control by insolation means that the surface is cooler under cloudy conditions than under clear skies. This control produces a much smaller interannual variability of the surface temperature and of the lapse rate than prevailing in winter, when the control is by advection. Regional climatic data would be of greatest value for agriculture and forestry if compiled for well-defined seasons. For continental northern latitudes, analysis presented here of factors controlling the surface temperature appears an appropriate tool for this task.

  13. International Space Station Environmental Control and Life Support System Acceptance Testing for Node 1 Temperature and Humidity Control Subsystem

    NASA Technical Reports Server (NTRS)

    Williams, David E.

    2011-01-01

    The International Space Station (ISS) Node 1 Environmental Control and Life Support (ECLS) System is comprised of five subsystems: Atmosphere Control and Storage (ACS), Atmosphere Revitalization (AR), Fire Detection and Suppression (FDS), Temperature and Humidity Control (THC), and Water Recovery and Management (WRM). This paper will provide a summary of the Node 1 ECLS THC subsystem design and a detailed discussion of the ISS ECLS Acceptance Testing methodology utilized for this subsystem.The International Space Station (ISS) Node 1 Environmental Control and Life Support (ECLS) System is comprised of five subsystems: Atmosphere Control and Storage (ACS), Atmosphere Revitalization (AR), Fire Detection and Suppression (FDS), Temperature and Humidity Control (THC), and Water Recovery and Management (WRM). This paper will provide a summary of the Node 1 ECLS THC subsystem design and a detailed discussion of the ISS ECLS Acceptance Testing methodology utilized for this subsystem.

  14. Circadian rhythm of temperature preference and its neural control in Drosophila

    PubMed Central

    Kaneko, Haruna; Head, Lauren M.; Ling, Jinli; Tang, Xin; Liu, Yilin; Hardin, Paul E.; Emery, Patrick; Hamada, Fumika N.

    2012-01-01

    A daily body temperature rhythm (BTR) is critical for the maintenance of homeostasis in mammals. While mammals use internal energy to regulate body temperature, ectotherms typically regulate body temperature behaviorally [1]. Some ectotherms maintain homeostasis via a daily temperature preference rhythm (TPR) [2], but the underlying mechanisms are largely unknown. Here, we show that Drosophila exhibit a daily circadian clock dependent TPR that resembles mammalian BTR. Pacemaker neurons critical for locomotor activity are not necessary for TPR; instead, the dorsal neuron 2s (DN2s), whose function was previously unknown, is sufficient. This indicates that TPR, like BTR, is controlled independently from locomotor activity. Therefore, the mechanisms controlling temperature fluctuations in fly TPR and mammalian BTR may share parallel features. Taken together, our results reveal the existence of a novel DN2- based circadian neural circuit that specifically regulates TPR; thus, understanding the mechanisms of TPR will shed new light on the function and neural control of circadian rhythms. PMID:22981774

  15. Geothermal and Hydrogeologic Controls on Regional Groundwater Temperatures

    NASA Astrophysics Data System (ADS)

    Burns, E. R.; Ingebritsen, S.; Williams, C. F.; Manga, M.

    2015-12-01

    A 1-D analytic solution for combined heat and groundwater flow through an aquifer system accounts for geothermal heating at the base of the aquifer, recharge of cooler water along the groundwater flow path, advection of heat within the aquifer, conduction of heat through the vadose zone, and viscous heating. The 1-D solution, which uses a freely available Python script, can be applied to moderately complex geometries by solving the heat flow equation for piece-wise linear or constant properties and boundary conditions. Analysis of the Eastern Snake River Plain regional aquifer system demonstrates that viscous heating, normally neglected by numerical solutions, is variably important along the groundwater flow path, and that heat conduction to the land surface and cool recharge are the primary thermal perturbations causing deviation from a steady, slow heating along the flow path. Because viscous heating is sometimes important, a general anisotropic form of the viscous heat-generation term has been derived and can be included in more complex 2-D and 3-D numerical solvers of the coupled heat and groundwater flow equations. The 1-D solution allows quick and easy determination of whether this term needs to be included. The rate at which thermal perturbations equilibrate with distance is controlled by the Peclet Number (the ratio of advective to conductive heat transport), which can be used to estimate the distance over which thermal perturbations (e.g., cool recharge or local geothermal hotspots) will be detectable.

  16. Dynamics of Weight Change and Temperature of Apis mellifera (Hymenoptera: Apidae) Colonies in a Wintering Building With Controlled Temperature.

    PubMed

    Stalidzans, E; Zacepins, A; Kviesis, A; Brusbardis, V; Meitalovs, J; Paura, L; Bulipopa, N; Liepniece, M

    2017-01-04

    Honey bee wintering in a wintering building (indoors) with controlled microclimate is used in some cold regions to minimize colony losses due to the hard weather conditions. The behavior and possible state of bee colonies in a dark room, isolated from natural environment during winter season, was studied by indirect temperature measurements to analyze the expression of their annual rhythm when it is not affected by ambient temperature, rain, snow, wind, and daylight. Thus, the observed behavior in the wintering building is initiated solely by bee colony internal processes. Experiments were carried out to determine the dynamics of temperature above the upper hive body and weight dynamics of indoors and outdoors wintered honey bee colonies and their brood-rearing performance in spring. We found significantly lower honey consumption-related weight loss of indoor wintered colonies compared with outdoor colonies, while no significant difference in the amount of open or sealed brood was found, suggesting that wintering building saves food and physiological resources without an impact on colony activity in spring. Indoor wintered colonies, with or without thermal insulation, did not have significant differences in food consumption and brood rearing in spring. The thermal behavior and weight dynamics of all experimental groups has changed in the middle of February possibly due to increased brood-rearing activity. Temperature measurement above the upper hive body is a convenient remote monitoring method of wintering process. Predictability of food consumption in a wintering building, with constant temperature, enables wintering without oversupply of wintering honey.

  17. A technique for brain temperature control during ischemia, suitable for measurements with ion-sensitive microelectrodes.

    PubMed

    Ekholm, A; Siesjö, B K

    1992-10-01

    A technique is described for maintaining rat brain temperature constant during ischemia, a technique that also allows measurements with, and calibration of, ion-sensitive microelectrodes under defined temperature conditions. The brain temperature is controlled by a stream of air of defined temperature and humidity, which is perfused through a box enclosing the animal's head. A device for calibration of ion-sensitive microelectrodes is temperature controlled by similar principles. The air stream is delivered by a heater/humidifier that is standard in many commercial respirators/ventilators. When the relative humidity of the air stream is greater than 98%, the neocortical temperature can be maintained within less than 0.5 degrees C during 15 min of ischemia. The biological applicability of the technique is discussed.

  18. Metal catalyst for low-temperature growth of controlled zinc oxide nanowires on arbitrary substrates.

    PubMed

    Kim, Baek Hyun; Kwon, Jae W

    2014-03-14

    Zinc oxide nanowires generated by hydrothermal method present superior physical and chemical characteristics. Quality control of the growth has been very challenging and controlled growth is only achievable under very limited conditions using homogeneous seed layers with high temperature processes. Here we show the controlled ZnO nanowire growth on various organic and inorganic materials without the requirement of a homogeneous seed layer and a high temperature process. We also report the discovery of an important role of the electronegativity in the nanowire growth on arbitrary substrates. Using heterogeneous metal oxide interlayers with low-temperature hydrothermal methods, we demonstrate well-controlled ZnO nanowire arrays and single nanowires on flat or curved surfaces. A metal catalyst and heterogeneous metal oxide interlayers are found to determine lattice-match with ZnO and to largely influence the controlled alignment. These findings will contribute to the development of novel nanodevices using controlled nanowires.

  19. Metal Catalyst for Low-Temperature Growth of Controlled Zinc Oxide Nanowires on Arbitrary Substrates

    PubMed Central

    Kim, Baek Hyun; Kwon, Jae W.

    2014-01-01

    Zinc oxide nanowires generated by hydrothermal method present superior physical and chemical characteristics. Quality control of the growth has been very challenging and controlled growth is only achievable under very limited conditions using homogeneous seed layers with high temperature processes. Here we show the controlled ZnO nanowire growth on various organic and inorganic materials without the requirement of a homogeneous seed layer and a high temperature process. We also report the discovery of an important role of the electronegativity in the nanowire growth on arbitrary substrates. Using heterogeneous metal oxide interlayers with low-temperature hydrothermal methods, we demonstrate well-controlled ZnO nanowire arrays and single nanowires on flat or curved surfaces. A metal catalyst and heterogeneous metal oxide interlayers are found to determine lattice-match with ZnO and to largely influence the controlled alignment. These findings will contribute to the development of novel nanodevices using controlled nanowires. PMID:24625584

  20. Application of fuzzy logic to the control of wind tunnel settling chamber temperature

    NASA Technical Reports Server (NTRS)

    Gwaltney, David A.; Humphreys, Gregory L.

    1994-01-01

    The application of Fuzzy Logic Controllers (FLC's) to the control of nonlinear processes, typically controlled by a human operator, is a topic of much study. Recent application of a microprocessor-based FLC to the control of temperature processes in several wind tunnels has proven to be very successful. The control of temperature processes in the wind tunnels requires the ability to monitor temperature feedback from several points and to accommodate varying operating conditions in the wind tunnels. The FLC has an intuitive and easily configurable structure which incorporates the flexibility required to have such an ability. The design and implementation of the FLC is presented along with process data from the wind tunnels under automatic control.

  1. Achieving nitritation in a continuous moving bed biofilm reactor at different temperatures through ratio control.

    PubMed

    Bian, Wei; Zhang, Shuyan; Zhang, Yanzhuo; Li, Wenjing; Kan, Ruizhe; Wang, Wenxiao; Zheng, Zhaoming; Li, Jun

    2017-02-01

    A ratio control strategy was implemented in a continuous moving bed biofilm reactor (MBBR) to investigate the response to different temperatures. The control strategy was designed to maintain a constant ratio between dissolved oxygen (DO) and total ammonia nitrogen (TAN) concentrations. The results revealed that a stable nitritation in a biofilm reactor could be achieved via ratio control, which compensated the negative influence of low temperatures by stronger oxygen-limiting conditions. Even with a temperature as low as 6°C, stable nitritation could be achieved when the controlling ratio did not exceed 0.17. Oxygen-limiting conditions in the biofilm reactor were determined by the DO/TAN concentrations ratio, instead of the mere DO concentration. This ratio control strategy allowed the achievement of stable nitritation without complete wash-out of NOB from the reactor. Through the ratio control strategy full nitritation of sidestream wastewater was allowed; however, for mainstream wastewater, only partial nitritation was recommended.

  2. A global evaluation of temperature and carbonate ion control on Mg/Ca ratios of ostracoda genus Krithe

    NASA Astrophysics Data System (ADS)

    Elmore, A. C.; Sosdian, S.; Rosenthal, Y.; Wright, J. D.

    2012-09-01

    Improving estimates of past ocean temperatures is paramount to our understanding of ocean circulation and its role in climate change. Magnesium/calcium (Mg/Ca) ratios of carapaces of the benthic ostracod genus Krithe were determined from new, globally distributed core top samples from the Norwegian Sea, Cape Hatteras shelf, Gulf of Mexico, Sulawesi Margin (Indonesia), New Zealand shelf, Ceara Rise, and the North Atlantic. A linear regression of the Krithe Mg/Ca ratios and bottom water temperature (BWT) reveals a significant correlation for locations where temperature during carapace calcification was above ˜3°C, which can be described by the equation Mg/Ca = (0.972 ± 0.152) * BWT + (7.948 ± 1.103) consistent with previous North Atlantic calibrations. Deviations from the global calibration line below ˜3°C follow the same pattern observed for benthic foraminifera, suggesting that the incorporation of magnesium into ostracodal calcite may be secondarily controlled by changes in carbonate ion concentration. Therefore, we propose a linear regression that describes the relationship between magnesium incorporation, temperature, and carbonate saturation for low temperatures (<3°C) Mg/Ca = (0.972 ± 0.152) * BWT + (0.100 ± 0.030) * Δ[CO32-]) + (4.440 ± 1.103) (1 SE = ± 0.3°C). While the standard error of the calibration is small, it requires an accurate knowledge of past Δ[CO32-] concentration, which necessitates additional proxy data. Applying the calibration to glacial samples from the deep North Atlantic Ocean we show that estimates of bottom water temperatures generated from the new Δ[CO32-]- corrected equations are more consistent with results from oxygen isotopes and pore water studies.

  3. Accurate Finite Difference Algorithms

    NASA Technical Reports Server (NTRS)

    Goodrich, John W.

    1996-01-01

    Two families of finite difference algorithms for computational aeroacoustics are presented and compared. All of the algorithms are single step explicit methods, they have the same order of accuracy in both space and time, with examples up to eleventh order, and they have multidimensional extensions. One of the algorithm families has spectral like high resolution. Propagation with high order and high resolution algorithms can produce accurate results after O(10(exp 6)) periods of propagation with eight grid points per wavelength.

  4. Accurate monotone cubic interpolation

    NASA Technical Reports Server (NTRS)

    Huynh, Hung T.

    1991-01-01

    Monotone piecewise cubic interpolants are simple and effective. They are generally third-order accurate, except near strict local extrema where accuracy degenerates to second-order due to the monotonicity constraint. Algorithms for piecewise cubic interpolants, which preserve monotonicity as well as uniform third and fourth-order accuracy are presented. The gain of accuracy is obtained by relaxing the monotonicity constraint in a geometric framework in which the median function plays a crucial role.

  5. Pulse tube cryocooler SQUID cooling system involving an infrared temperature controller cooled by a cryocooler

    NASA Astrophysics Data System (ADS)

    Tanaka, S.; Iwao, S.; Hatsukade, Y.

    2005-10-01

    We propose a pulse tube cryocooler SQUID cooling system, which temperature was controlled by an infrared source. A high-Tc SQUID magnetometer was mounted and cooled by a coaxial pulse tube cryocooler. A light from a halogen lamp was guided by a quartz flexible bundle fiber and was introduced to the cold head. The output power of the lamp was controlled by a temperature controller in accordance with the cold stage temperature. As a result, the flux noise of the SQUID output was not changed in the range of 1-1000 Hz regardless of the lamp power. The temperature could be controlled at 77 K with accuracy of ±0.03 K for long time duration more than 2 h. This demonstrated that the system can be applied to any applications such as NDE systems.

  6. Importance of temperature control for HEFLEX, a biological experiment for Spacelab 1. [plant gravitational physiology study

    NASA Technical Reports Server (NTRS)

    Chapman, D. K.; Brown, A. H.

    1979-01-01

    The importance of temperature control to HEFLEX, a Spacelab experiment designed to measure kinetic properties of Helianthis nutation in a low-g environment, is discussed. It is argued that the development of the HEFLEX experiment has been severely hampered by the inadequate control of ambient air temperature provided by the spacecraft module design. A worst case calculation shows that delivery of only 69% of the maximum yield of useful data from the HEFLEX system is guaranteed; significant data losses from inadequate temperature control are expected. The magnitude of the expected data losses indicates that the cost reductions associated with imprecise temperature controls may prove to be a false economy in the long term.

  7. Tomato flavor changes at chilling and non-chilling temperatures as influenced by controlled atmospheres

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Postharvest temperatures recommended as safe to avoid chilling injury (CI) based on lack of visible symptoms suppress tomato aroma development. We investigated how temperatures at or above the putative CI threshold of 12.5°C affected aroma of pink ‘Tasti Lee’ tomatoes and if controlled atmosphere (C...

  8. 49 CFR 173.224 - Packaging and control and emergency temperatures for self-reactive materials.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 2 2014-10-01 2014-10-01 false Packaging and control and emergency temperatures... temperatures for self-reactive materials. (a) General. When the § 172.101 table of this subchapter specifies... packagings meeting Packing Group I are not authorized. Self-reactive materials which require...

  9. 49 CFR 173.224 - Packaging and control and emergency temperatures for self-reactive materials.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 2 2012-10-01 2012-10-01 false Packaging and control and emergency temperatures... temperatures for self-reactive materials. (a) General. When the § 172.101 table of this subchapter specifies... packagings meeting Packing Group I are not authorized. Self-reactive materials which require...

  10. 49 CFR 173.224 - Packaging and control and emergency temperatures for self-reactive materials.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 2 2013-10-01 2013-10-01 false Packaging and control and emergency temperatures... temperatures for self-reactive materials. (a) General. When the § 172.101 table of this subchapter specifies... packagings meeting Packing Group I are not authorized. Self-reactive materials which require...

  11. Temperature control and calibration issues in the growth, processing and characterization of electronic materials

    NASA Technical Reports Server (NTRS)

    Wilson, B. A.

    1989-01-01

    The temperature control and calibration issues encountered in the growth, processing, and characterization of electronic materials are summarized. The primary problem area is identified as temperature control during epitaxial materials growth. While qualitative thermal measurements are feasible and reproducibility is often achievable within a given system, absolute calibration is essentially impossible in many cases, precluding the possibility of portability from one system to another. The procedures utilized for thermal measurements during epitaxial growth are described, and their limitations discussed.

  12. Controlled simulation of optical turbulence in a temperature gradient air chamber

    NASA Astrophysics Data System (ADS)

    Toselli, Italo; Wang, Fei; Korotkova, Olga

    2016-05-01

    Atmospheric turbulence simulator is built and characterized for in-lab optical wave propagation with controlled strength of the refractive-index fluctuations. The temperature gradients are generated by a sequence of heat guns with controlled individual strengths. The temperature structure functions are measured in two directions transverse to propagation path with the help of a thermocouple array and used for evaluation of the corresponding refractive-index structure functions of optical turbulence.

  13. Fast and accurate exhaled breath ammonia measurement.

    PubMed

    Solga, Steven F; Mudalel, Matthew L; Spacek, Lisa A; Risby, Terence H

    2014-06-11

    This exhaled breath ammonia method uses a fast and highly sensitive spectroscopic method known as quartz enhanced photoacoustic spectroscopy (QEPAS) that uses a quantum cascade based laser. The monitor is coupled to a sampler that measures mouth pressure and carbon dioxide. The system is temperature controlled and specifically designed to address the reactivity of this compound. The sampler provides immediate feedback to the subject and the technician on the quality of the breath effort. Together with the quick response time of the monitor, this system is capable of accurately measuring exhaled breath ammonia representative of deep lung systemic levels. Because the system is easy to use and produces real time results, it has enabled experiments to identify factors that influence measurements. For example, mouth rinse and oral pH reproducibly and significantly affect results and therefore must be controlled. Temperature and mode of breathing are other examples. As our understanding of these factors evolves, error is reduced, and clinical studies become more meaningful. This system is very reliable and individual measurements are inexpensive. The sampler is relatively inexpensive and quite portable, but the monitor is neither. This limits options for some clinical studies and provides rational for future innovations.

  14. Fuzzy Predictive Control Strategy in the Application of the Industrial Furnace Temperature Control

    NASA Astrophysics Data System (ADS)

    Dai, Luping; Chen, Xingliang; Chen, Liu; Liu, Xia

    Ceramic kiln with large heat capacity, big lag and nonlinear characteristic, this paper proposes a combining fuzzy control and predictive control of the control algorithm, to enhance the tracking and anti-interference ability of the algorithm. The simulation results show, this method compared with the control of PID has the high steady precision and dynamic characteristic.

  15. Research on temperature control with numerical regulators in electric resistance furnaces with indirect heating

    NASA Astrophysics Data System (ADS)

    Diniş, C. M.; Popa, G. N.; Iagăr, A.

    2016-02-01

    The paper is an analysis of two-positions (hysteresis) regulators, self-tuned PID controller and PID controller for temperature control used for indirect heat resistance furnaces. For PID controller was used three methods of tuning: Ziegler-Nichols step response model, Cohen-Coon tuning rules and Ziegler-Nichols tuning rules. In experiments it used an electric furnace with indirect heating with active power of resistance of 1 kW/230V AC and a numerical temperature regulator AT-503 type (ANLY). It got a much better temperature control when using the Cohen-Coon tuning rules method than those of Ziegler-Nichols step response method and Ziegler-Nichols tuning rules method.

  16. Method and apparatus for controlling combustor temperature during transient load changes

    DOEpatents

    Clingerman, Bruce J.; Chalfant, Robert W.

    2002-01-01

    A method and apparatus for controlling the temperature of a combustor in a fuel cell apparatus includes a fast acting air bypass valve connected in parallel with an air inlet to the combustor. A predetermined excess quantity of air is supplied from an air source to a series connected fuel cell and combustor. The predetermined excess quantity of air is provided in a sufficient amount to control the temperature of the combustor during start-up of the fuel processor when the load on the fuel cell is zero and to accommodate any temperature transients during operation of the fuel cell.

  17. How light, temperature, and measurement and growth [CO2] interactively control isoprene emission in hybrid aspen

    PubMed Central

    Niinemets, Ülo; Sun, Zhihong

    2015-01-01

    Plant isoprene emissions have been modelled assuming independent controls by light, temperature and atmospheric [CO2]. However, the isoprene emission rate is ultimately controlled by the pool size of its immediate substrate, dimethylallyl diphosphate (DMADP), and isoprene synthase activity, implying that the environmental controls might interact. In addition, acclimation to growth [CO2] can shift the share of the control by DMADP pool size and isoprene synthase activity, and thereby alter the environmental sensitivity. Environmental controls of isoprene emission were studied in hybrid aspen (Populus tremula × Populus tremuloides) saplings acclimated either to ambient [CO2] of 380 μmol mol–1 or elevated [CO2] of 780 μmol mol–1. The data demonstrated strong interactive effects of environmental drivers and growth [CO2] on isoprene emissions. Light enhancement of isoprene emission was the greatest at intermediate temperatures and was greater in elevated-[CO2]-grown plants, indicating greater enhancement of the DMADP supply. The optimum temperature for isoprene emission was higher at lower light, suggesting activation of alternative DMADP sinks at higher light. In addition, [CO2] inhibition of isoprene emission was lost at a higher temperature with particularly strong effects in elevated-[CO2]-grown plants. Nevertheless, DMADP pool size was still predicted to more strongly control isoprene emission at higher temperatures in elevated-[CO2]-grown plants. We argue that interactive environmental controls and acclimation to growth [CO2] should be incorporated in future isoprene emission models at the level of DMADP pool size. PMID:25399006

  18. A crystallization apparatus for temperature-controlled flow-cell dialysis with real-time visualization

    PubMed Central

    Junius, Niels; Oksanen, Esko; Terrien, Maxime; Berzin, Christophe; Ferrer, Jean-Luc; Budayova-Spano, Monika

    2016-01-01

    Many instrumentation developments in crystallization have concentrated on massive parallelization assays and reduction of sample volume per experiment to find initial crystallization conditions. Yet improving the size and diffraction quality of the crystals for diffraction studies often requires decoupling of crystal nucleation and growth. This in turn requires the control of variables such as precipitant and protein concentration, equilibration rate, and temperature, which are all difficult parameters to control in the existing setups. The success of the temperature-controlled batch method, originally developed to grow very large crystals for neutron crystallography, demonstrated that the rational optimization of crystal growth has potential in structural biology. A temperature-controlled dialysis button has been developed for our previous device, and a prototype of an integrated apparatus for the rational optimization of crystal growth by mapping and manipulating temperature–precipitant concentration phase diagrams has been constructed. The presented approach differs from the current paradigm, since it involves serial instead of parallel experiments, exploring multiple crystallization conditions with the same protein sample. The sample is not consumed in the experiment and the conditions can be changed in a reversible fashion, using dialysis with a flowing precipitant reservoir as well as precise temperature control. The control software allows visualization of the crystals, as well as control of the temperature and composition of the crystallization solution. The rational crystallization optimization strategies presented here allow tailoring of crystal size, morphology and diffraction quality, significantly reducing the time, effort and amount of expensive protein material required for structure determination. PMID:27275137

  19. Substrate temperature control for the formation of metal nanohelices by glancing angle deposition

    SciTech Connect

    Sumigawa, Takashi Sakurai, Atsushi; Iwata, Kazuya; Chen, Shaoguang; Kitamura, Takayuki; Tanie, Hisashi

    2015-11-15

    The targets of this study are to develop a device to precisely control the temperature during glancing angle deposition, to make films consisting of low melting temperature metal nanoelements with a controlled shape (helix), and to explore the substrate temperature for controlling the nanoshapes. A vacuum evaporation system capable of both cooling a substrate and measurement of its temperature was used to form thin films consisting of arrays of Cu and Al nanohelices on silicon substrates by maintaining the substrate temperature at T{sub s}/T{sub m} < 0.22 (T{sub s} is the substrate temperature and T{sub m} is the melting temperature of target material). The critical T{sub s}/T{sub m} to produce Cu and Al nanohelices corresponds to the transitional homologous temperature between zones I and II in the structure zone model for the solid film, where surface diffusion becomes dominant. X-ray diffraction analysis indicated that the Cu and Al nanohelix thin films were composed of coarse oriented grains with diameters of several tens of nanometers.

  20. Improved Temperature Dynamic Model of Turbine Subcomponents for Facilitation of Generalized Tip Clearance Control

    NASA Technical Reports Server (NTRS)

    Kypuros, Javier A.; Colson, Rodrigo; Munoz, Afredo

    2004-01-01

    This paper describes efforts conducted to improve dynamic temperature estimations of a turbine tip clearance system to facilitate design of a generalized tip clearance controller. This work builds upon research previously conducted and presented in and focuses primarily on improving dynamic temperature estimations of the primary components affecting tip clearance (i.e. the rotor, blades, and casing/shroud). The temperature profiles estimated by the previous model iteration, specifically for the rotor and blades, were found to be inaccurate and, more importantly, insufficient to facilitate controller design. Some assumptions made to facilitate the previous results were not valid, and thus improvements are presented here to better match the physical reality. As will be shown, the improved temperature sub- models, match a commercially validated model and are sufficiently simplified to aid in controller design.

  1. Nonlinear dynamics of homeothermic temperature control in skunk cabbage, Symplocarpus foetidus

    NASA Astrophysics Data System (ADS)

    Ito, Takanori; Ito, Kikukatsu

    2005-11-01

    Certain primitive plants undergo orchestrated temperature control during flowering. Skunk cabbage, Symplocarpus foetidus, has been demonstrated to maintain an internal temperature of around 20 °C even when the ambient temperature drops below freezing. However, it is not clear whether a unique algorithm controls the homeothermic behavior of S. foetidus, or whether such an algorithm might exhibit linear or nonlinear thermoregulatory dynamics. Here we report the underlying dynamics of temperature control in S. foetidus using nonlinear forecasting, attractor and correlation dimension analyses. It was shown that thermoregulation in S. foetidus was governed by low-dimensional chaotic dynamics, the geometry of which showed a strange attractor named the “Zazen attractor.” Our data suggest that the chaotic thermoregulation in S. foetidus is inherent and that it is an adaptive response to the natural environment.

  2. Temperature-dependent variation in gas exchange patterns and spiracular control in Rhodnius prolixus.

    PubMed

    Heinrich, Erica; Bradley, Timothy

    2014-08-01

    Insects display an array of respiratory behaviors, including the use of discontinuous gas exchange. This pattern is characterized by periods of spiracular closure, micro-openings (flutter), and complete openings during which the majority of gas exchange takes place. A current model of insect spiracular control suggests that spiracles are controlled by two interacting feedback loops, which produce the discontinuous pattern. The flutter period is thought to be initiated by a critically low partial pressure of oxygen, while the open period is initiated by a critically high CO2 threshold. The goal of our study was to test this control model under conditions of feeding-induced or temperature-induced changes in metabolic rate. We manipulated the metabolic rate of the insect Rhodnius prolixus using two discrete mechanisms: (1) feeding the insects a bloodmeal or (2) exposing them to a range of temperatures (18-38°C). Examining the variation in the gas exchange patterns produced by insects in each of these treatments allowed us to determine whether spiracular control is sensitive to metabolic rate and/or temperature. We found that increases in temperature caused significant decreases in open phase burst volumes and premature abandonment of discontinuous gas exchange cycles. These effects were not observed in fed individuals maintained at a single temperature despite their higher metabolic rates. Our results indicate that some part of the spiracular control mechanism is temperature sensitive, suggesting a possible role for pH in CO2 sensing.

  3. Temperature control during regeneration of activated carbon fiber cloth with resistance-feedback.

    PubMed

    Johnsen, David L; Rood, Mark J

    2012-10-16

    Electrothermal swing adsorption (ESA) of organic compounds from gas streams with activated carbon fiber cloth (ACFC) reduces emissions to the atmosphere and recovers feedstock for reuse. Local temperature measurement (e.g., with a thermocouple) is typically used to monitor/control adsorbent regeneration cycles. Remote electrical resistance measurement is evaluated here as an alternative to local temperature measurement. ACFC resistance that was modeled based on its physical properties was within 10.5% of the measured resistance values during electrothermal heating. Resistance control was developed based on this measured relationship and used to control temperature to within 2.3% of regeneration set-point temperatures. Isobutane-laden adsorbent was then heated with resistance control. After 2 min of heating, the temperature of the adsorbent with isobutane was 13% less than the adsorbent without isobutane. This difference decreased to 2.1% after 9 min of heating, showing desorption of isobutane. An ACFC cartridge was also heated to 175 °C for 900 cycles with its resistance and adsorption capacity values remaining within 3% and 2%, respectively. This new method to control regeneration power application based on rapid sensing of the adsorbent's resistance removes the need for direct-contact temperature sensors providing a simple, cost-efficient, and long-term regeneration technique for ESA systems.

  4. Development of Automatic Controller of Brain Temperature Based on the Conditions of Clinical Use

    NASA Astrophysics Data System (ADS)

    Utsuki, Tomohiko; Wakamatsu, Hidetoshi

    A new automatic controller of brain temperature was developed based on the inevitable conditions of its clinical use from the viewpoint of various kinds of feasibility, in particular, electric power consumption of less than 1,500W in ICU. The adaptive algorithm was employed to cope with individual time-varying characteristic change of patients. The controller under water-surface cooling hypothermia requires much power for the frequent regulation of the water temperature of cooling blankets. Thus, in this study, the power consumption of the controller was checked by several kinds of examinations involving the control simulation of brain temperature using a mannequin with thermal characteristics similar to that of adult patients. The required accuracy of therapeutic brain hypothermia, i.e. control deviation within ±0.1C was experimentally confirmed using “root mean square of the control error”, despite the present controller consumes less energy comparing with the one in the case of our conventional controller, where it can still keeps remaining power margin more than 300W even in the full operation. Thereby, the clinically required water temperature was also confirmed within the limit of power supply, thus its practical application is highly expected with less physical burden of medical staff inclusive of more usability and more medical cost performance.

  5. 3. DETAIL OF RACKS AND TEMPERATURE/HUMIDITY CONTROL SYSTEM IN CURING ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    3. DETAIL OF RACKS AND TEMPERATURE/HUMIDITY CONTROL SYSTEM IN CURING ROOM ON LEVEL 6; LOOKING SOUTHEAST; ENVIRONMENT INSIDE THE CURING ROOM WAS CONTROLLED BY NIAGARA MODEL 87007 SPRAY COOLER AND BUFFALO FORGE CENTRIFUGAL FAN IN BACKGROUND - Rath Packing Company, Cooler Building, Sycamore Street between Elm & Eighteenth Streets, Waterloo, Black Hawk County, IA

  6. Estimating controls systems for HVAC: A guide to pricing temperature controls systems for commercial buildings

    SciTech Connect

    Edwards, H.J. Jr.

    1986-01-01

    This book covers design, marketing, estimating, managing, specifications, fail-safe considerations, equipment and purchasing. It demonstrates estimating procedures for both controls installation and maintenance contracts - techniques applicable to pneumatic, electric, or hybrid control systems.

  7. A fast and accurate method for controlling the correct labeling of products containing buffalo meat using High Resolution Melting (HRM) analysis.

    PubMed

    Sakaridis, Ioannis; Ganopoulos, Ioannis; Argiriou, Anagnostis; Tsaftaris, Athanasios

    2013-05-01

    The substitution of high priced meat with low cost ones and the fraudulent labeling of meat products make the identification and traceability of meat species and their processed products in the food chain important. A polymerase chain reaction followed by a High Resolution Melting (HRM) analysis was developed for species specific detection of buffalo; it was applied in six commercial meat products. A pair of specific 12S and universal 18S rRNA primers were employed and yielded DNA fragments of 220bp and 77bp, respectively. All tested products were found to contain buffalo meat and presented melting curves with at least two visible inflection points derived from the amplicons of the 12S specific and 18S universal primers. The presence of buffalo meat in meat products and the adulteration of buffalo products with unknown species were established down to a level of 0.1%. HRM was proven to be a fast and accurate technique for authentication testing of meat products.

  8. Electrostatic control over temperature-dependent tunnelling across a single-molecule junction

    PubMed Central

    Garrigues, Alvar R.; Wang, Lejia; del Barco, Enrique; Nijhuis, Christian A.

    2016-01-01

    Understanding how the mechanism of charge transport through molecular tunnel junctions depends on temperature is crucial to control electronic function in molecular electronic devices. With just a few systems investigated as a function of bias and temperature so far, thermal effects in molecular tunnel junctions remain poorly understood. Here we report a detailed charge transport study of an individual redox-active ferrocene-based molecule over a wide range of temperatures and applied potentials. The results show the temperature dependence of the current to vary strongly as a function of the gate voltage. Specifically, the current across the molecule exponentially increases in the Coulomb blockade regime and decreases at the charge degeneracy points, while remaining temperature-independent at resonance. Our observations can be well accounted for by a formal single-level tunnelling model where the temperature dependence relies on the thermal broadening of the Fermi distributions of the electrons in the leads. PMID:27211787

  9. Automatically controlled high temperature furnace for the first firing of porcelain products

    SciTech Connect

    Kryzhanovskii, K.S.; Davidenko, V.K.; Oliyarnik, P.N.

    1987-11-01

    A computer-controlled gas furnace, intended for the first firing of porcelain products, is described. The design specifications include measures taken for protecting the firing products from contamination by combustion products and structural imhomogeneities caused by nonuniform temperature distributions, as well as temperature and combustion control regimes to ensure maximum energy utilization during firing. Burner and fuel system configurations are described, performance data on fuel economy, quality control, and productivity are determined, and results of a cost benefit analysis on the implementation of the furnace in industry are given.

  10. Mill profiler machines soft materials accurately

    NASA Technical Reports Server (NTRS)

    Rauschl, J. A.

    1966-01-01

    Mill profiler machines bevels, slots, and grooves in soft materials, such as styrofoam phenolic-filled cores, to any desired thickness. A single operator can accurately control cutting depths in contour or straight line work.

  11. High-dimensional immunomonitoring models of HIV-1–specific CD8 T-cell responses accurately identify subjects achieving spontaneous viral control

    PubMed Central

    Ndhlovu, Zaza M.; Chibnik, Lori B.; Proudfoot, Jacqueline; Vine, Seanna; McMullen, Ashley; Cesa, Kevin; Porichis, Filippos; Jones, R. Brad; Alvino, Donna Marie; Hart, Meghan G.; Stampouloglou, Eleni; Piechocka-Trocha, Alicja; Kadie, Carl; Pereyra, Florencia; Heckerman, David; De Jager, Philip L.; Walker, Bruce D.

    2013-01-01

    The development of immunomonitoring models to determine HIV-1 vaccine efficacy is a major challenge. Studies suggest that HIV-1–specific CD8 T cells play a critical role in subjects achieving spontaneous viral control (HIV-1 controllers) and that they will be important in immune interventions. However, no single CD8 T-cell function is uniquely associated with controller status and the heterogeneity of responses targeting different epitopes further complicates the discovery of determinants of protective immunity. In the present study, we describe immunomonitoring models integrating multiple functions of epitope-specific CD8 T cells that distinguish controllers from subjects with treated or untreated progressive infection. Models integrating higher numbers of variables and trained with the least absolute shrinkage and selection operator (LASSO) variant of logistic regression and 10-fold cross-validation produce “diagnostic tests” that display an excellent capacity to delineate subject categories. The test accuracy reaches 75% area under the receiving operating characteristic curve in cohorts matched for prevalence of protective alleles. Linear mixed-effects model analyses show that the proliferative capacity, cytokine production, and kinetics of cytokine secretion are associated with HIV-1 control. Although proliferative capacity is the strongest single discriminant, integrated modeling of different dimensions of data leverages individual associations. This strategy may have important applications in predictive model development and immune monitoring of HIV-1 vaccine trials. PMID:23233659

  12. An efficient transmission power control scheme for temperature variation in wireless sensor networks.

    PubMed

    Lee, Jungwook; Chung, Kwangsue

    2011-01-01

    Wireless sensor networks collect data from several nodes dispersed at remote sites. Sensor nodes can be installed in harsh environments such as deserts, cities, and indoors, where the link quality changes considerably over time. Particularly, changes in transmission power may be caused by temperature, humidity, and other factors. In order to compensate for link quality changes, existing schemes detect the link quality changes between nodes and control transmission power through a series of feedback processes, but these approaches can cause heavy overhead with the additional control packets needed. In this paper, the change of the link quality according to temperature is examined through empirical experimentation. A new power control scheme combining both temperature-aware link quality compensation and a closed-loop feedback process to adapt to link quality changes is proposed. We prove that the proposed scheme effectively adapts the transmission power to the changing link quality with less control overhead and energy consumption.

  13. An Efficient Transmission Power Control Scheme for Temperature Variation in Wireless Sensor Networks

    PubMed Central

    Lee, Jungwook; Chung, Kwangsue

    2011-01-01

    Wireless sensor networks collect data from several nodes dispersed at remote sites. Sensor nodes can be installed in harsh environments such as deserts, cities, and indoors, where the link quality changes considerably over time. Particularly, changes in transmission power may be caused by temperature, humidity, and other factors. In order to compensate for link quality changes, existing schemes detect the link quality changes between nodes and control transmission power through a series of feedback processes, but these approaches can cause heavy overhead with the additional control packets needed. In this paper, the change of the link quality according to temperature is examined through empirical experimentation. A new power control scheme combining both temperature-aware link quality compensation and a closed-loop feedback process to adapt to link quality changes is proposed. We prove that the proposed scheme effectively adapts the transmission power to the changing link quality with less control overhead and energy consumption. PMID:22163787

  14. Controlling factors of Ca isotope fractionation in scleractinian corals evaluated by temperature, pH and light controlled culture experiments

    NASA Astrophysics Data System (ADS)

    Inoue, Mayuri; Gussone, Nikolaus; Koga, Yasuko; Iwase, Akihiro; Suzuki, Atsushi; Sakai, Kazuhiko; Kawahata, Hodaka

    2015-10-01

    In this study, the 44Ca/40Ca ratios of Porites australiensis grown under three different culture experiments composed of temperature, pH and light controlled culture experiments are measured. The temperature dependent isotope fractionation of 0.02‰/°C deduced from this study is similar to inorganic aragonite, but the degree of isotope fractionation is about +0.4‰ offset in corals. These observations agree with earlier results on different coral species, suggesting Ca isotope fractionation during Ca transmembrane transport in corals. While in cultured corals a significant temperature dependence of δ44Ca is observed, the relationships between calcium isotope fractionation and pH as well as light intensity are negligible. Therefore variation of δ44Ca in Porites corals is mainly controlled by temperature. A combination of δ44Ca and Sr/Ca of corals in temperature controlled experiments cannot be explained by Rayleigh type fractionation directly from a fluid, which is seawater-like in terms of δ44Ca and Sr/Ca. Through coral-specific biomineralization processes, overall mean δ44Ca of scleractinian corals including previous studies are different from biogenic aragonites secreted by sclerosponges and pteropods, but are comparable with those of bivalves as well as calcitic coccolithophores and foraminifers. These findings are important for better understanding biomineralization in corals and in order to constrain the Ca isotopic composition of oceanic Ca sinks in response to climate changes and associated with shifts of calcite and aragonite seas.

  15. Controlling the temperature of bones using pulsed CO2 lasers: observations and mathematical modeling.

    PubMed

    Lévesque, Luc; Noël, Jean-Marc; Scott, Calum

    2015-12-01

    Temperature of porcine bone specimens are investigated by aiming a pulsed CO2 laser beam at the bone-air surface. This method of controlling temperature is believed to be flexible in medical applications as it avoids the uses of thermal devices, which are often cumbersome and generate rather larger temperature variations with time. The control of temperature using this method is modeled by the heat-conduction equation. In this investigation, it is assumed that the energy delivered by the CO2 laser is confined within a very thin surface layer of roughly 9 μm. It is shown that temperature can be maintained at a steady temperature using a CO2 laser and we demonstrate that the method can be adapted to be used in tandem with another laser beam. This method to control the temperature is believed to be useful in de-contamination of bone during the implantation treatment, in bone augmentation when using natural or synthetic materials and in low-level laser therapy.

  16. Accurate quantum chemical calculations

    NASA Technical Reports Server (NTRS)

    Bauschlicher, Charles W., Jr.; Langhoff, Stephen R.; Taylor, Peter R.

    1989-01-01

    An important goal of quantum chemical calculations is to provide an understanding of chemical bonding and molecular electronic structure. A second goal, the prediction of energy differences to chemical accuracy, has been much harder to attain. First, the computational resources required to achieve such accuracy are very large, and second, it is not straightforward to demonstrate that an apparently accurate result, in terms of agreement with experiment, does not result from a cancellation of errors. Recent advances in electronic structure methodology, coupled with the power of vector supercomputers, have made it possible to solve a number of electronic structure problems exactly using the full configuration interaction (FCI) method within a subspace of the complete Hilbert space. These exact results can be used to benchmark approximate techniques that are applicable to a wider range of chemical and physical problems. The methodology of many-electron quantum chemistry is reviewed. Methods are considered in detail for performing FCI calculations. The application of FCI methods to several three-electron problems in molecular physics are discussed. A number of benchmark applications of FCI wave functions are described. Atomic basis sets and the development of improved methods for handling very large basis sets are discussed: these are then applied to a number of chemical and spectroscopic problems; to transition metals; and to problems involving potential energy surfaces. Although the experiences described give considerable grounds for optimism about the general ability to perform accurate calculations, there are several problems that have proved less tractable, at least with current computer resources, and these and possible solutions are discussed.

  17. An ergodic configurational thermostat using selective control of higher order temperatures.

    PubMed

    Patra, Puneet Kumar; Bhattacharya, Baidurya

    2015-05-21

    The conventional Nosé-Hoover type deterministic thermostat scheme for controlling temperature by configurational variables (Braga-Travis (BT) thermostat) is non-ergodic for systems with a few degrees of freedom. While for the original Nosé-Hoover kinetic thermostat ergodicity has been achieved by controlling the higher order moments of kinetic energy, the issues of nonergodicity of BT thermostat persists. In this paper, we introduce two new measures of configurational temperature (second and third order) based on the generalized temperature-curvature relationship and obtain a family of deterministic thermostatting schemes by selectively (and simultaneously) controlling the different orders of temperatures through pseudo-friction terms. The ergodic characteristics of the proposed thermostats are tested using a single harmonic oscillator through statistical (normality of joint distributions at different Poincare sections) as well as dynamical tests (difference of the minimum and maximum largest Lyapunov exponent). Our results indicate that simultaneously controlling the first and the second order configurational temperatures (C(1,2) thermostat) is sufficient to make the dynamics ergodic. A 2000 particle Lennard-Jones system is subjected to (i) equilibrium and (ii) sudden temperature change under BT and C(1,2) thermostatting schemes. The C(1,2) thermostat is found to be more robust than the BT thermostat without increasing computational costs.

  18. A non-contact temperature measurement system for controlling photothermal medical laser treatments

    NASA Astrophysics Data System (ADS)

    Kaya, Ã.-zgür; Gülsoy, Murat

    2016-03-01

    Photothermal medical laser treatments are extremely dependent on the generated tissue temperature. It is necessary to reach a certain temperature threshold to achieve successful results, whereas preventing to exceed an upper temperature value is required to avoid thermal damage. One method to overcome this problem is to use previously conducted dosimetry studies as a reference. Nevertheless, these results are acquired in controlled environments using uniform subjects. In the clinical environment, the optical and thermal characteristics (tissue color, composition and hydration level) vary dramatically among different patients. Therefore, the most reliable solution is to use a closed-loop feedback system that monitors the target tissue temperature to control laser exposure. In this study, we present a compact, non-contact temperature measurement system for the control of photothermal medical laser applications that is cost-efficient and simple to use. The temperature measurement is achieved using a focused, commercially available MOEMS infrared thermocouple sensor embedded in an off-axis arrangement on the laser beam delivery hand probe. The spot size of the temperature sensor is ca. 2.5 mm, reasonably smaller than the laser spot sizes used in photothermal medical laser applications. The temperature readout and laser control is realized using a microcontroller for fast operation. The utilization of the developed system may enable the adaptation of several medical laser treatments that are currently conducted only in controlled laboratory environments into the clinic. Laser tissue welding and cartilage reshaping are two of the techniques that are limited to laboratory research at the moment. This system will also ensure the safety and success of laser treatments aiming hyperthermia, coagulation and ablation, as well as LLLT and PDT.

  19. Low temperature dry etching of chromium towards control at sub-5 nm dimensions

    NASA Astrophysics Data System (ADS)

    Staaks, Daniel; Yang, XiaoMin; Lee, Kim Y.; Dhuey, Scott D.; Sassolini, Simone; Rangelow, Ivo W.; Olynick, Deirdre L.

    2016-10-01

    Patterned chromium and its compounds are crucial materials for nanoscale patterning and chromium based devices. Here we investigate how temperature can be used to control chromium etching using chlorine/oxygen gas mixtures. Oxygen/chlorine ratios between 0% and 100% and temperatures between -100 °C and +40 °C are studied. Spectroscopic ellipsometry is used to precisely measure rates, chlorination, and the thickness dependence of n and k. Working in the extremes of oxygen content (very high or very low) and lower temperatures, we find rates can be controlled to nanometers per minute. Activation energies are measured and show that etch mechanisms are both temperature and oxygen level dependent. Furthermore, we find that etching temperature can manipulate the surface chemistry. One surprising consequence is that at low oxygen levels, Etching rates increase with decreasing temperature. Preliminary feature-profile studies show the extremes of temperature and oxygen provide advantages over commonly used room temperature processing conditions. One example is with higher ion energies at -100 °C, where etching products deposit.

  20. Importance of behavior and morphological traits for controlling body temperature in littorinid snails.

    PubMed

    Miller, Luke P; Denny, Mark W

    2011-06-01

    For organisms living in the intertidal zone, temperature is an important selective agent that can shape species distributions and drive phenotypic variation among populations. Littorinid snails, which occupy the upper limits of rocky shores and estuaries worldwide, often experience extreme high temperatures and prolonged aerial emersion during low tides, yet their robust physiology--coupled with morphological and behavioral traits--permits these gastropods to persist and exert strong grazing control over algal communities. We use a mechanistic heat-budget model to compare the effects of behavioral and morphological traits on the body temperatures of five species of littorinid snails under natural weather conditions. Model predictions and field experiments indicate that, for all five species, the relative contribution of shell color or sculpturing to temperature regulation is small, on the order of 0.2-2 °C, while behavioral choices such as removing the foot from the substratum or reorienting the shell can lower body temperatures by 2-4 °C on average. Temperatures in central California rarely exceeded the thermal tolerance limits of the local littorinid species during the study period, but at sites where snails are regularly exposed to extreme high temperatures, the functional significance of the tested traits may be important. The mechanistic approach used here provides the ability to gauge the importance of behavioral and morphological traits for controlling body temperature as species approach their physiological thresholds.

  1. Modeling and open-loop control of IPMC actuators under changing ambient temperature

    NASA Astrophysics Data System (ADS)

    Dong, Roy; Tan, Xiaobo

    2012-06-01

    Because of the cost and complexity associated with sensory feedback, open-loop control of ionic polymer-metal composite (IPMC) actuators is of interest in many biomedical and robotic applications. However, the performance of an open-loop controller is sensitive to the change in IPMC dynamics, which is influenced heavily by ambient environmental conditions including the temperature. In this paper we propose a novel approach to the modeling and open-loop control of temperature-dependent IPMC actuation dynamics. An IPMC actuator is modeled empirically with a transfer function, the zeros and poles of which are functions of the temperature. With auxiliary temperature measurement, open-loop control is realized by inverting the model at the current ambient temperature. We use a stable but noncausal algorithm to deal with non-minimum-phase zeros in the system that would prevent directly inverting the dynamics. Experimental results are presented to show the effectiveness of the proposed approach in open-loop tracking control of IPMC actuators.

  2. Does phylogeny control U37K -temperature sensitivity? Implications for lacustrine alkenone paleothermometry

    NASA Astrophysics Data System (ADS)

    D'Andrea, William J.; Theroux, Susanna; Bradley, Raymond S.; Huang, Xiaohui

    2016-02-01

    Alkenone paleothermometry (via the U37K and U37K‧ indices) has long been used to reconstruct sea surface temperature and has more recently been proven effective in lacustrine settings. Genetic analyses indicate that there is a diversity of different alkenone-producing lacustrine haptophytes, and differences among U37K -temperature calibrations suggest that unique calibrations might be required to quantify past temperature variation from individual lakes. The only term necessary to quantify U37K -inferred temperature relative to a reference period (e.g., modern temperature 20th Century mean) is the slope of the calibration regression, the U37K -temperature sensitivity (i.e., the change in U37K per °C temperature change). Here, we bring together all of the existing U37K -temperature calibrations in order to compare the variability among U37K -temperature sensitivities. We also report a new in situ U37K -temperature calibration along with environmental genomic analysis based on the 18S rRNA gene of an alkenone producing haptophyte from lake Vikvatnet in Norway. We propose and test the hypothesis that U37K -temperature sensitivity is controlled by phylogeny and that this term can be used to quantify past temperature variation from lake sediments if the genetic identity of the lake's alkenone-producer is known. Using the existing calibration data sets, we determine four phylotype-specific U37K -temperature sensitivities for use in cases where in situ calibration is unavailable but the phylogeny of the alkenone producers is known.

  3. Study on the idity fuzzy neural network controller based on improved genetic algorithm of intelligent temperature control system in vegetable greenhouse

    NASA Astrophysics Data System (ADS)

    Zhang, Su; Yuan, Hongbo; Zhou, Yuhong; Wang, Nan

    2009-07-01

    In order to create the environment that the suitable crop grows, direct against the characteristic of the system of the greenhouse. The aim of the research was to study the intelligent temperature control system in vegetable greenhouse. Based on computer automatic control ,a kind of intelligent temperature control system in vegetable greenhouse was designed. The design thought of systematic hardwares such as temperature collection system, temperature display, control system, heater control circuit in the heater were expounded in detail The control algorithm of the system was improved and system simulation was made by using MATLAB finally. The control algorithm of the system was improved by a new fuzzy neural network controller. The stimulation curve showed that the system had better controlling and tracking performances ,higher accuracy of controlling the temperature. And this system and host epigyny computer could constitute the secondary computer control system which was favorable for realizing the centralized management of the production.

  4. Temperature control using a heat exchanger of a cardioplegic system in cardiopulmonary bypass model for rats.

    PubMed

    Kim, Won Gon; Choi, Se Hun; Kim, Jin Hyun

    2008-12-01

    Small animal cardiopulmonary bypass (CPB) model would be a valuable tool for investigating pathophysiological and therapeutic strategies on bypass. However, the rat CPB models have a number of technical limitations. Effective maintenance and control of core temperature by heat exchanger (HE) is among them. The purpose of this study was to confirm the effect of rectal temperature maintenance and hypothermic control using a HE of cardioplegia system in CPB model for rats. The miniature circuit consisted of a reservoir, HE, membrane oxygenator, and roller pump; the static priming volume was 40 cc. In the first stage of experiment, 10 male Sprague-Dawley rats were divided into two groups; HE group was subjected to CPB with HE from a cardioplegia system, and control group was subjected to CPB with warm water circulating around the reservoir. Partial CPB was conducted at a flow rate of 40 mg/kg/min for 20 min after venous cannulation (via the internal jugular vein) and arterial cannulation (via the femoral artery). Rectal temperature was measured after anesthetic induction, after cannulation, 5, 10, 15, and 20 min after CPB. Arterial blood gas with hematocrit was also analyzed, 5 and 15 min after CPB. In the second stage with the same experimental setting, rectal temperatures were lowered in 10 rats to the target temperature of 32 degrees C. After reaching the target temperature, animals were rewarmed. Rectal temperature was measured after cannulation, 5, 10, 15, 20, 25, and 30 min after CPB. Arterial blood gas with hematocrit was also analyzed, 5 and 15 min after CPB. Rectal temperature change differed between the two groups (P < 0.01). The temperatures of the HE group were well maintained during CPB, whereas the control group was under progressive hypothermia. Rectal temperature 20 min after CPB was 36.16 +/- 0.32 degrees C in the HE group and 34.22 +/- 0.36 degrees C in the control group. In the second set of experiments, the hypothermia targeted (32 degrees C) was

  5. Realization of tin freezing point using a loop heat pipe-based hydraulic temperature control technique

    NASA Astrophysics Data System (ADS)

    Joung, Wukchul; Gam, Kee Sool; Kim, Yong-Gyoo

    2015-10-01

    In this work, the freezing point of tin (Sn FP) was realized by inside nucleation where the supercooling of tin and the reheating of the sample after the nucleation were achieved without extracting the cell from an isothermal apparatus. To this end, a novel hydraulic temperature control technique, which was based on the thermo-hydraulic characteristics of a pressure-controlled loop heat pipe (LHP), was employed to provide a slow cooling of the sample for deep supercooling and fast reheating after nucleation to minimize the amount of initial freeze of the sample. The required temperature controls were achieved by the active pressure control of a control gas inside the compensation chamber of the pressure-controlled LHP, and slow cooling at  -0.05 K min-1 for the deep supercooling of tin and fast heating at 2 K min-1 for reheating the sample after nucleation was attained. Based on this hydraulic temperature control technique, the nucleation of tin was realized at supercooling of around 19 K, and a satisfactorily fast reheating of the sample to the plateau-producing temperature (i.e. 0.5 K below the Sn FP) was achieved without any temperature overshoots of the isothermal region. The inside-nucleated Sn FP showed many desirable features compared to the Sn FP realized by the conventional outside nucleation method. The longer freezing plateaus and the better immersion characteristics of the Sn FP were obtained by inside nucleation, and the measured freezing temperature of the inside-nucleated Sn FP was as much as 0.37 mK higher than the outside-nucleated Sn FP with an expanded uncertainty of 0.19 mK. Details on the experiment are provided and explanations for the observed differences are discussed.

  6. Temperature feedback-controlled photothermal treatment with diffusing applicator: theoretical and experimental evaluations

    PubMed Central

    Nguyen, Trung Hau; Park, Suhyun; Hlaing, Kyu Kyu; Kang, Hyun Wook

    2016-01-01

    To minimize thermal injury, the current study evaluated the real-time temperature monitoring with a proportional-integrative-derivative (PID) controller during 980-nm photothermal treatment with a radially-diffusing applicator. Both simulations and experiments demonstrated comparable thermal behaviors in temperature distribution and the degree of irreversible tissue denaturation. The PID-controlled application constantly maintained the pre-determined temperature of 353 K (steady-state error = < 1 K). Due to constant energy delivery, coagulation volumes linearly increased up to 1.04 ± 0.02 cm3 with irradiation time. Integration of temperature feedback with diffuser-assisted photothermal treatments can provide a feasible therapeutic modality to treat pancreatic tumors in an effective manner. PMID:27231632

  7. Robust control of speed and temperature in a power plant gas turbine.

    PubMed

    Najimi, Ebrahim; Ramezani, Mohammad Hossein

    2012-03-01

    In this paper, an H(∞) robust controller has been designed for an identified model of MONTAZER GHAEM power plant gas turbine (GE9001E). In design phase, a linear model (ARX model) which is obtained using real data has been applied. Since the turbine has been used in a combined cycle power plant, its speed and also the exhaust gas temperature should be adjusted simultaneously by controlling fuel signals and compressor inlet guide vane (IGV) position. Considering the limitations on the system inputs, the aim of the control is to maintain the turbine speed and the exhaust gas temperature within desired interval under uncertainties and load demand disturbances. Simulation results of applying the proposed robust controller on the nonlinear model of the system (NARX model), fairly fulfilled the predefined aims. Simulations also show the improvement in the performance compared to MPC and PID controllers for the same conditions.

  8. Model-based control rescues boiler from steam-temperature excursions

    SciTech Connect

    Hanson, K.; Werre, J.; Chloupek, J.; Richerson, J.

    1995-05-01

    This article describes how, after operators of a lignite-fired boiler wrestled for years to control its main steam temperature, a switch to model-based control resolved the problem. Decoupling of control loops was essential. Montana Dakota Utilities (MDU) is the operator of the Coyote station, a 450-MW unit located at Beulah, ND, in the heart of lignite country. Owners of the plant are MDU, Northern Municipal Power Agency, Northwestern Public Service Co., and Otter Tail Power Co. The unit, a Babcock and Wilcox Co. (Barberton, Ohio) drum-boiler design, came on line in 1981. It burns lignite with a heating value of 6,900 Btu/lb using 12 cyclones. Because of unique boiler characteristics and controls implementation using several different control systems, the Coyote station had experienced significant steam-temperature excursions over the years.

  9. Averaged kinetic temperature controlling algorithm: Application to spontaneous alloying in microclusters

    NASA Astrophysics Data System (ADS)

    Kobayashi, Taizo R.; Ikeda, Kensuke S.; Shimizu, Yasushi; Sawada, Shin-ichi

    2003-04-01

    A simple algorithm of velocity scaling is proposed for the isothermal simulation of nonequilibrium relaxation processes accompanied with heat generation or absorption. The algorithm controls the kinetic temperature averaged over an arbitrary time interval at an arbitrary relaxation rate and at an arbitrary velocity scaling interval. The general conditions of controlling temperature are derived analytically and criteria for stable control are established. Our algorithm is applied to simulating the effect of substrate on the "spontaneous alloying" process of metal microclusters [H. Yasuda, H. Mori, M. Komatsu, K. Takeda, and H. Fujita, J. Electron Microsc. 41, 267 (1992)]. The results are compared with the results obtained by the Langevin algorithm in which the kinetic energy of every atom is controlled by respective stochastic heat reservoir. In spite of the marked difference between the two algorithms the relaxation dynamics agree very well in quantity over a sufficient wide range of control parameters.

  10. Homeostatic and circadian control of body temperature in the fat-tailed gerbil.

    PubMed

    Refinetti, R

    1998-01-01

    The interplay of homeostasis and circadian rhythmicity in the control of body temperature was studied in the fat-tailed gerbil (Pachyuromys duprasi). In a first study, the body temperature rhythm of 8 gerbils maintained at 24 degrees C under a 14L:10D light-dark cycle was studied by telemetry. Data from 9 other species of small mammals were also obtained for comparison. The gerbils were found to exhibit a robust rhythm of body temperature (the most robust of the 10 species) with a high plateau during the dark phase of the light-dark cycle and a low plateau during the light phase. In a second experiment, 5 gerbils were allowed to select the temperature of their environment by moving along a thermal gradient. The animals consistently selected higher ambient temperatures during the light phase of the light-dark cycle (when their body temperature was at the low plateau). In a third experiment, the metabolic response of 8 gerbils to an acute cold exposure was determined by indirect calorimetry. Greater cold-induced thermogenesis was observed during the light phase. The fact that the animals selected higher ambient temperatures and displayed greater cold-induced thermogenesis when their body temperature was lower contradicts the hypothesis that the body temperature rhythm is caused by a rhythmic oscillation of the thermoregulatory set point.

  11. Control performances of a piezoactuator direct drive valve system at high temperatures with thermal insulation

    NASA Astrophysics Data System (ADS)

    Han, Yung-Min; Han, Chulhee; Kim, Wan Ho; Seong, Ho Yong; Choi, Seung-Bok

    2016-09-01

    This technical note presents control performances of a piezoactuator direct drive valve (PDDV) operated at high temperature environment. After briefly discussing operating principle and mechanical dimensions of the proposed PDDV, an appropriate size of the PDDV is manufactured. As a first step, the temperature effect on the valve performance is experimentally investigated by measuring the spool displacement at various temperatures. Subsequently, the PDDV is thermally insulated using aerogel and installed in a large-size heat chamber in which the pneumatic-hydraulic cylinders and sensors are equipped. A proportional-integral-derivative feedback controller is then designed and implemented to control the spool displacement of the valve system. In this work, the spool displacement is chosen as a control variable since it is directly related to the flow rate of the valve system. Three different sinusoidal displacements with different frequencies of 1, 10 and 50 Hz are used as reference spool displacement and tracking controls are undertaken up to 150 °C. It is shown that the proposed PDDV with the thermal insulation can provide favorable control responses without significant tracking errors at high temperatures.

  12. Enhanced nanoscale imaging of polymer blends by temperature-controlled selective dissolution.

    PubMed

    Friedel, Bettina; Ehrler, Bruno; Hüttner, Sven; Greenham, Neil C

    2012-01-23

    Nanoscale imaging on polymer blends is vital, especially in organic electronics. By using temperature-controlled selective dissolution, the 3D structure of a thin film becomes accessible without the expensive search for adequate orthogonal solvents. The method, which takes advantage of the temperature dependence of the solubility, is demonstrated to image P3HT:PCBM and P3HT:F8TBT photovoltaic blend films using atomic force and scanning electron microscopy.

  13. Article comprising a garment or other textile structure for use in controlling body temperature

    DOEpatents

    Butzer, Melissa J.

    2000-01-01

    There is disclosed an article for use in cooling body temperature which comprises a garment having a coat and pant, with each having a body section adapted to receive a portion of the torso of the wearer and extensions from the body section to receive the wearer's limbs. The garment includes a system for circulating temperature controlling fluid from a suitable source through patches removably received in pockets in each of body section and extensions.

  14. System and method for air temperature control in an oxygen transport membrane based reactor

    DOEpatents

    Kelly, Sean M

    2016-09-27

    A system and method for air temperature control in an oxygen transport membrane based reactor is provided. The system and method involves introducing a specific quantity of cooling air or trim air in between stages in a multistage oxygen transport membrane based reactor or furnace to maintain generally consistent surface temperatures of the oxygen transport membrane elements and associated reactors. The associated reactors may include reforming reactors, boilers or process gas heaters.

  15. System and method for temperature control in an oxygen transport membrane based reactor

    DOEpatents

    Kelly, Sean M.

    2017-02-21

    A system and method for temperature control in an oxygen transport membrane based reactor is provided. The system and method involves introducing a specific quantity of cooling air or trim air in between stages in a multistage oxygen transport membrane based reactor or furnace to maintain generally consistent surface temperatures of the oxygen transport membrane elements and associated reactors. The associated reactors may include reforming reactors, boilers or process gas heaters.

  16. Thermoelectric Converter for Loop Heat Pipe Temperature Control: Experience and Lessons Learned

    NASA Technical Reports Server (NTRS)

    Ku, Jentung; Ottenstein, Laura

    2010-01-01

    This paper describes the theoretical background and implementation methodology of using a thermoelectric converter (TEC) for operating temperature control of a loop heat pipe (LHP). In particular, experimental results from ambient and thermal vacuum tests of an LHP are presented for illustrations. The most commonly used state-of-the-art method to control the LHP operating temperature is to cold bias its compensation chamber (CC) and use an electrical heater to maintain the CC at the desired set point temperature. Although effective, this approach has its shortcomings in that the electrical heater can only provide heating to the CC, and the required power can be large under certain conditions. An alternative method is to use a TEC, which is capable of providing both heating and cooling to the CC. In this method, one side of the TEC is attached to the CC, and the other side is connected to the evaporator via a thermal strap. Using a bipolar power supply and a control algorithm, a TEC can function as a heater or a cooler, depending on the direction of the current flow. Extensive ground tests of several LHPs have demonstrated that a TEC can provide very tight temperature control for the CC. It also offers several additional advantages: (1) The LHP can operate at temperatures below its natural operating temperature at low heat loads; (2) The required heater power for a TEC is much less than that for an electrical heater; and (3) It enhances the LHP start-up success. Although the concept of using a TEC for LHP temperature control is simple, there are many factors to be considered in its implementation for space applications because the TEC is susceptible to the shear stress and yet has to sustain the dynamic load under the spacecraft launch environment. The added features that help the TEC to withstand the dynamic load will inevitably affect the TEC thermal performance. Some experiences and lessons learned are addressed in this paper.

  17. A fast solution switching system with temperature control for single cell measurements

    PubMed Central

    Koh, Duk-Su; Chen, Liangyi; Ufret-Vincenty, Carmen A.; Jung, Seung-Ryoung

    2011-01-01

    This article describes a perfusion system for biophysical single cell experiments at the physiological temperature. Our system regulates temperature of test solutions using a small heat exchanger that includes several capillaries. Water circulating inside the heat exchanger warms or cools test solutions flowing inside the capillaries. Temperature-controlled solutions are delivered directly to a single cell(s) through a multibarreled manifold that switches solutions bathing a cell in less than 1 s. This solution exchange is optimal for patch clamp, single-cell microamperometry, and microfluorometry experiments. Using this system, we demonstrate that exocytosis from pancreatic β cells and activation of TRPV1 channels are temperature sensitive. We also discuss how to measure local temperature near a single cell under investigation. PMID:21536068

  18. A particle temperature sensor for monitoring and control of the thermal spray process

    SciTech Connect

    Swank, W.D.; Fincke, J.R.; Haggard, D.C.

    1995-12-01

    The temperature and velocity of thermally sprayed particles prior to their impact on the substrate are two of the predominant determinants of coating quality and characteristics. This paper describes an instrument developed for real time monitoring of in-flight particle temperature in an industrial environment. The instrument is designed to operate as a stand alone device for verifying that a desired particle temperature is attained or for developing process settings to yield a particular temperature. The device is also suitable for incorporation into a closed loop process controller. Data showing the relationship between torch parameters and average particle temperature are presented. There is good agreement between previous measurements using laboratory instrumentation and the simpler, industrially hardened technique described here. The assumption of gray body behavior is evaluated and for known emissivities corrections are developed.

  19. Nano-Kelvin thermometry and temperature control: beyond the thermal noise limit.

    PubMed

    Weng, Wenle; Anstie, James D; Stace, Thomas M; Campbell, Geoff; Baynes, Fred N; Luiten, Andre N

    2014-04-25

    We demonstrate thermometry with a resolution of 80  nK/Hz using an isotropic crystalline whispering-gallery mode resonator based on a dichroic dual-mode technique. We simultaneously excite two modes that have a mode frequency ratio that is very close to two (±0.3  ppm). The wavelength and temperature dependence of the refractive index means that the frequency difference between these modes is an ultrasensitive proxy of the resonator temperature. This approach to temperature sensing automatically suppresses sensitivity to thermal expansion and vibrationally induced changes of the resonator. We also demonstrate active suppression of temperature fluctuations in the resonator by controlling the intensity of the driving laser. The residual temperature fluctuations are shown to be below the limits set by fundamental thermodynamic fluctuations of the resonator material.

  20. BIOACCESSIBILITY TESTS ACCURATELY ESTIMATE ...

    EPA Pesticide Factsheets

    Hazards of soil-borne Pb to wild birds may be more accurately quantified if the bioavailability of that Pb is known. To better understand the bioavailability of Pb to birds, we measured blood Pb concentrations in Japanese quail (Coturnix japonica) fed diets containing Pb-contaminated soils. Relative bioavailabilities were expressed by comparison with blood Pb concentrations in quail fed a Pb acetate reference diet. Diets containing soil from five Pb-contaminated Superfund sites had relative bioavailabilities from 33%-63%, with a mean of about 50%. Treatment of two of the soils with P significantly reduced the bioavailability of Pb. The bioaccessibility of the Pb in the test soils was then measured in six in vitro tests and regressed on bioavailability. They were: the “Relative Bioavailability Leaching Procedure” (RBALP) at pH 1.5, the same test conducted at pH 2.5, the “Ohio State University In vitro Gastrointestinal” method (OSU IVG), the “Urban Soil Bioaccessible Lead Test”, the modified “Physiologically Based Extraction Test” and the “Waterfowl Physiologically Based Extraction Test.” All regressions had positive slopes. Based on criteria of slope and coefficient of determination, the RBALP pH 2.5 and OSU IVG tests performed very well. Speciation by X-ray absorption spectroscopy demonstrated that, on average, most of the Pb in the sampled soils was sorbed to minerals (30%), bound to organic matter 24%, or present as Pb sulfate 18%. Ad

  1. Nonlocal control of electron temperature in short direct current glow discharge plasma

    SciTech Connect

    Demidov, V. I.; Kudryavtsev, A. A.; Stepanova, O. M.; Kurlyandskaya, I. P.

    2014-09-15

    To demonstrate controlling the electron temperature in nonlocal plasma, experiments have been performed on a short (without positive column) dc glow discharge with a cold cathode by applying different voltages to the conducting discharge wall. The experiments have been performed for low-pressure noble gas discharges. The applied voltage can modify trapping the energetic electrons emitted from the cathode sheath and arising from the atomic and molecular processes in the plasma within the device volume. This phenomenon results in the energetic electrons heating the slow plasma electrons, which consequently modifies the electron temperature. Furthermore, a numerical model of the discharge has demonstrated the electron temperature modification for the above case.

  2. Temperature-controlled optical stimulation of the rat prostate cavernous nerves.

    PubMed

    Tozburun, Serhat; Hutchens, Thomas C; McClain, Michael A; Lagoda, Gwen A; Burnett, Arthur L; Fried, Nathaniel M

    2013-06-01

    Optical nerve stimulation (ONS) may be useful as a diagnostic tool for intraoperative identification and preservation of the prostate cavernous nerves (CN), responsible for erectile function, during prostate cancer surgery. Successful ONS requires elevating the nerve temperature to within a narrow range (~42 to 47°C) for nerve activation without thermal damage to the nerve. This preliminary study explores a prototype temperature-controlled optical nerve stimulation (TC-ONS) system for maintaining a constant (±1°C) nerve temperature during short-term ONS of the rat prostate CNs. A 150-mW, 1455-nm diode laser was operated in continuous-wave mode, with and without temperature control, during stimulation of the rat CNs for 15 to 30 s through a fiber optic probe with a 1-mm-diameter spot. A microcontroller opened and closed an in-line mechanical shutter in response to an infrared sensor, with a predetermined temperature set point. With TC-ONS, higher laser power settings were used to rapidly and safely elevate the CNs to a temperature necessary for a fast intracavernous pressure response, while also preventing excessive temperatures that would otherwise cause thermal damage to the nerve. With further development, TC-ONS may provide a rapid, stable, and safe method for intraoperative identification and preservation of the prostate CNs.

  3. A Review of Heating and Temperature Control in Microfluidic Systems: Techniques and Applications

    PubMed Central

    Miralles, Vincent; Huerre, Axel; Malloggi, Florent; Jullien, Marie-Caroline

    2013-01-01

    This review presents an overview of the different techniques developed over the last decade to regulate the temperature within microfluidic systems. A variety of different approaches has been adopted, from external heating sources to Joule heating, microwaves or the use of lasers to cite just a few examples. The scope of the technical solutions developed to date is impressive and encompasses for instance temperature ramp rates ranging from 0.1 to 2,000 °C/s leading to homogeneous temperatures from −3 °C to 120 °C, and constant gradients from 6 to 40 °C/mm with a fair degree of accuracy. We also examine some recent strategies developed for applications such as digital microfluidics, where integration of a heating source to generate a temperature gradient offers control of a key parameter, without necessarily requiring great accuracy. Conversely, Temperature Gradient Focusing requires high accuracy in order to control both the concentration and separation of charged species. In addition, the Polymerase Chain Reaction requires both accuracy (homogeneous temperature) and integration to carry out demanding heating cycles. The spectrum of applications requiring temperature regulation is growing rapidly with increasingly important implications for the physical, chemical and biotechnological sectors, depending on the relevant heating technique. PMID:26835667

  4. Low temperature limits photoperiod control of smolting in atlantic salmon through endocrine mechanisms

    USGS Publications Warehouse

    McCormick, S.D.; Moriyama, S.

    2000-01-01

    We have examined the interaction of photoperiod and temperature in regulating the parr-smolt transformation and its endocrine control. Atlantic salmon juveniles were reared at a constant temperature of 10??C or ambient temperature (2??C from January to April followed by seasonal increase) under simulated natural day length. At 10??C, an increase in day length [16 h of light and 8 h of darkness (LD 16:8)] in February accelerated increases in gill Na+K+-ATPase activity, whereas fish at ambient temperature did not respond to increased day length. Increases in gill Na+K+-ATPase activity under both photoperiods occurred later at ambient temperature than at 10??C. Plasma growth hormone (GH), insulin-like growth factor, and thyroxine increased within 7 days of increased day length at 10??C and remained elevated for 5-9 wk; the same photoperiod treatment at 2??C resulted in much smaller increases of shorter duration. Plasma cortisol increased transiently 3 and 5 wk after LD 16:8 at 10??C and ambient temperature, respectively. Plasma thyroxine was consistently higher at ambient temperature than at 10??C. Plasma triiodothyronine was initially higher at 10??C than at ambient temperature, and there was no response to LD 16:8 under either temperature regimen. There was a strong correlation between gill Na+K+-ATPase activity and plasma GH; correlations were weaker with other hormones. The results provide evidence that low temperature limits the physiological response to increased day length and that GH, insulin-like growth factor I, cortisol, and thyroid hormones mediate the environmental control of the parr-smolt transformation.

  5. Automatic Incubator-type Temperature Control System for Brain Hypothermia Treatment

    NASA Astrophysics Data System (ADS)

    Gaohua, Lu; Wakamatsu, Hidetoshi

    An automatic air-cooling incubator is proposed to replace the manual water-cooling blanket to control the brain tissue temperature for brain hypothermia treatment. Its feasibility is theoretically discussed as follows: First, an adult patient with the cooling incubator is modeled as a linear dynamical patient-incubator biothermal system. The patient is represented by an 18-compartment structure and described by its state equations. The air-cooling incubator provides almost same cooling effect as the water-cooling blanket, if a light breeze of speed around 3 m/s is circulated in the incubator. Then, in order to control the brain temperature automatically, an adaptive-optimal control algorithm is adopted, while the patient-blanket therapeutic system is considered as a reference model. Finally, the brain temperature of the patient-incubator biothermal system is controlled to follow up the given reference temperature course, in which an adaptive algorithm is confirmed useful for unknown environmental change and/or metabolic rate change of the patient in the incubating system. Thus, the present work ensures the development of the automatic air-cooling incubator for a better temperature regulation of the brain hypothermia treatment in ICU.

  6. Improved Temperature Sounding and Quality Control Methodology Using AIRS/AMSU Data: The AIRS Science Team Version 5 Retrieval Algorithm

    NASA Technical Reports Server (NTRS)

    Susskind, Joel; Blaisdell, John M.; Iredell, Lena; Keita, Fricky

    2009-01-01

    This paper describes the AIRS Science Team Version 5 retrieval algorithm in terms of its three most significant improvements over the methodology used in the AIRS Science Team Version 4 retrieval algorithm. Improved physics in Version 5 allows for use of AIRS clear column radiances in the entire 4.3 micron CO2 absorption band in the retrieval of temperature profiles T(p) during both day and night. Tropospheric sounding 15 micron CO2 observations are now used primarily in the generation of clear column radiances .R(sub i) for all channels. This new approach allows for the generation of more accurate values of .R(sub i) and T(p) under most cloud conditions. Secondly, Version 5 contains a new methodology to provide accurate case-by-case error estimates for retrieved geophysical parameters and for channel-by-channel clear column radiances. Thresholds of these error estimates are used in a new approach for Quality Control. Finally, Version 5 also contains for the first time an approach to provide AIRS soundings in partially cloudy conditions that does not require use of any microwave data. This new AIRS Only sounding methodology, referred to as AIRS Version 5 AO, was developed as a backup to AIRS Version 5 should the AMSU-A instrument fail. Results are shown comparing the relative performance of the AIRS Version 4, Version 5, and Version 5 AO for the single day, January 25, 2003. The Goddard DISC is now generating and distributing products derived using the AIRS Science Team Version 5 retrieval algorithm. This paper also described the Quality Control flags contained in the DISC AIRS/AMSU retrieval products and their intended use for scientific research purposes.

  7. The design of an embedded system for controlling humidity and temperature room

    NASA Astrophysics Data System (ADS)

    Dwi Teguh, R.; Didik Eko, S.; Laksono, Pringgo D.; Jamaluddin, Anif

    2016-11-01

    The aim of the system is to design an embedded system for maintenance confortable room. The confortable room was design by controlling temperature (on range 18 - 34 °C) and humidity (on range 40% - 70%.) of room condition. Temperature and humidity of room were maintained using four variable such as lamp for warm, water pump for distributing water vapour, a fan for air circullation and an exhaust-fan for air cleaner. The system was constucted both hardware (humidity sensor, microcontroller, pump, lamp, fan) and software (arduino IDE). The result shows that the system was perfectly performed to control room condition.

  8. Local control of light polarization with low-temperature fiber optics.

    PubMed

    Mack, A H; Riordon, J; Dean, C R; Talbot, R; Gervais, G

    2007-06-01

    A fiber-optic-based polarization control system that uses a backreflection measurement scheme at low temperatures has been developed. This provides a stringent test of the light polarization state at the output of the fiber, allowing for determination and control of the degree of circular polarization; i.e., it can generate linear, right, or left circular polarization with cryogenic fibers. This polarization controller is paving the way toward the control and manipulation of nuclear spins in semiconductors via the optical Overhauser effect and could be used, for example, for the purpose of quantum information processing with the large nuclear spins of GaAs.

  9. Accurate spectral color measurements

    NASA Astrophysics Data System (ADS)

    Hiltunen, Jouni; Jaeaeskelaeinen, Timo; Parkkinen, Jussi P. S.

    1999-08-01

    Surface color measurement is of importance in a very wide range of industrial applications including paint, paper, printing, photography, textiles, plastics and so on. For a demanding color measurements spectral approach is often needed. One can measure a color spectrum with a spectrophotometer using calibrated standard samples as a reference. Because it is impossible to define absolute color values of a sample, we always work with approximations. The human eye can perceive color difference as small as 0.5 CIELAB units and thus distinguish millions of colors. This 0.5 unit difference should be a goal for the precise color measurements. This limit is not a problem if we only want to measure the color difference of two samples, but if we want to know in a same time exact color coordinate values accuracy problems arise. The values of two instruments can be astonishingly different. The accuracy of the instrument used in color measurement may depend on various errors such as photometric non-linearity, wavelength error, integrating sphere dark level error, integrating sphere error in both specular included and specular excluded modes. Thus the correction formulas should be used to get more accurate results. Another question is how many channels i.e. wavelengths we are using to measure a spectrum. It is obvious that the sampling interval should be short to get more precise results. Furthermore, the result we get is always compromise of measuring time, conditions and cost. Sometimes we have to use portable syste or the shape and the size of samples makes it impossible to use sensitive equipment. In this study a small set of calibrated color tiles measured with the Perkin Elmer Lamda 18 and the Minolta CM-2002 spectrophotometers are compared. In the paper we explain the typical error sources of spectral color measurements, and show which are the accuracy demands a good colorimeter should have.

  10. RHIC 12x150A current lead temperature controller: design and implementation

    SciTech Connect

    Mi, C.; Seberg, S.; Ganetis, Hamdi, K.; Louie, W.; Heppner, G.; Jamilkowski, J.; Bruno, D.; DiLieto, A.; Sirio, C.; Tuozzolo, J.; Sandberg, J.; Unger, K.

    2011-03-28

    There are 60 12 x 150A current leads distributed in six RHIC service buildings; each lead delivers power supply current from room temperature to cryogenic temperature in RHIC. Due to the humid environment, condensation occurs frequently and ice forms quickly during operation, especially during an extensive storage period. These conditions generate warnings and alarms to which personnel must respond and establish temporary solutions to keep the machine operating. In here, we designed a temperature control system to avoid such situations. This paper discusses its design, implementation, and some results. There are six service buildings in the RHIC complex; each building has two valve boxes that transfer room-temperature current cables from the power supplies into superconducting leads, and then transport them into the RHIC tunnel. In there, the transition between the room-temperature lead into superconducting lead is critical and essential; smooth running during the physics store is crucial for the machine's continuing operation. One of the problems that often occurred previously was the icing of these current leads that could result in a potential leakage current onto ground, thereby preventing a continuous supply of physics store. Fig. 1 illustrates a typical example on a power lead. Among the modifications of the design of the valve box, we list below the new requirements for designing the temperature controller to prevent icing occurring: (1) Remotely control, monitor, and record each current lead's temperature in real time. Prevent icing or overheating of a power lead. (2) Include a temperature alarm for the high/low level threshold. In this paper we discuss the design, implementation, upgrades to, and operation of this new system.

  11. The Effects of Increased Body Temperature on Motor Control during Golf Putting.

    PubMed

    Mathers, John F; Grealy, Madeleine A

    2016-01-01

    This study investigated the effect of increased core temperature on the performance outcome and movement kinematics of elite golfers during a golf putting task. The study aimed to examine individual differences in the extent to which increased temperature influenced the rate of putting success, whether increased temperature speeded up the timing of the putting downswing and whether elite golfers changed their movement kinematics during times of thermal stress. Six participants performed 20 putts to each of four putt distances (1, 2, 3, and 4 m) under normal temperature conditions and when core body temperature was increased. There was no significant difference in the number of successful putts between the two temperature conditions, but there was an increase in putterhead velocity at ball impact on successful putts to distances of 1 and 4 m when temperature was elevated. This reflected an increase in swing amplitude rather than a reduction in swing duration as hypothesized. There were individual differences in the motor control response to thermal stress as three of the golfers changed the kinematic parameters used to scale their putting movements to achieve putts of different distances at elevated temperatures. Theoretical implications for these findings and the practical implications for elite golfers and future research are discussed.

  12. The Effects of Increased Body Temperature on Motor Control during Golf Putting

    PubMed Central

    Mathers, John F.; Grealy, Madeleine A.

    2016-01-01

    This study investigated the effect of increased core temperature on the performance outcome and movement kinematics of elite golfers during a golf putting task. The study aimed to examine individual differences in the extent to which increased temperature influenced the rate of putting success, whether increased temperature speeded up the timing of the putting downswing and whether elite golfers changed their movement kinematics during times of thermal stress. Six participants performed 20 putts to each of four putt distances (1, 2, 3, and 4 m) under normal temperature conditions and when core body temperature was increased. There was no significant difference in the number of successful putts between the two temperature conditions, but there was an increase in putterhead velocity at ball impact on successful putts to distances of 1 and 4 m when temperature was elevated. This reflected an increase in swing amplitude rather than a reduction in swing duration as hypothesized. There were individual differences in the motor control response to thermal stress as three of the golfers changed the kinematic parameters used to scale their putting movements to achieve putts of different distances at elevated temperatures. Theoretical implications for these findings and the practical implications for elite golfers and future research are discussed. PMID:27630588

  13. Thermoregulatory consequences of long-term microwave exposure at controlled ambient temperatures. Final report

    SciTech Connect

    Adair, E.R.; Spiers, D.E.; Rawson, R.O.; Adams, B.W.; Sheldon, D.K.

    1984-08-01

    The study was designed to identify and measure changes in thermoregulatory response systems, both behavioral and physiological, that may occur when squirrel monkeys are exposed to 2450-MHz CW microwaves 40 hours/week for 15 weeks. Microwave power densities explored were 1 and 5 mW/sq. cm. (SAR = 0.16 W/kg per mW/sq. cm.) and were presented at controlled environmental temperatures of 25, 30, and 35 C. Standardized tests, conducted periodically, assessed changes in thermoregulatory responses. Dependent variables measured included body mass, certain blood properties, metabolic heat production, sweating, skin temperatures, deep body temperature, and behavioral responses by which the monkeys selected a preferred environmental temperature. Results showed no alteration of metabolic rate, internal body temperature, or thermoregulatory behavior by microwave exposure although the ambient temperature prevailing during chronic exposure could exert an effect. An increase in sweating rate occurred in the 35 C environment, not enhanced significantly by microwave exposure. Skin temperature, reflecting vasomotor state, was reliably influenced by both ambient temperature and microwaves. The most robust consequence of microwave exposure was a reduction in body mass which appeared to be a function of microwave power density.

  14. Temperature sensitivity analysis of polarity controlled electrostatically doped tunnel field-effect transistor

    NASA Astrophysics Data System (ADS)

    Nigam, Kaushal; Pandey, Sunil; Kondekar, P. N.; Sharma, Dheeraj

    2016-09-01

    The conventional tunnel field-effect transistors (TFETs) have shown potential to scale down in sub-22 nm regime due to its lower sub-threshold slope and robustness against short-channel effects (SCEs), however, sensitivity towards temperature variation is a major concern. Therefore, for the first time, we investigate temperature sensitivity analysis of a polarity controlled electrostatically doped tunnel field-effect transistor (ED-TFET). Different performance metrics and analog/RF figure-of-merits were considered and compared for both devices, and simulations were performed using Silvaco ATLAS device tool. We found that the variation in ON-state current in ED-TFET is almost temperature independent due to electrostatically doped mechanism, while, it increases in conventional TFET at higher temperature. Above room temperature, the variation in ION, IOFF, and SS sensitivity in ED-TFET are only 0.11%/K, 2.21%/K, and 0.63%/K, while, in conventional TFET the variations are 0.43%/K, 2.99%/K, and 0.71%/K, respectively. However, below room temperature, the variation in ED-TFET ION is 0.195%/K compared to 0.27%/K of conventional TFET. Moreover, it is analysed that the incomplete ionization effect in conventional TFET severely affects the drive current and the threshold voltage, while, ED-TFET remains unaffected. Hence, the proposed ED-TFET is less sensitive towards temperature variation and can be used for cryogenics as well as for high temperature applications.

  15. Humboldt's spa: microbial diversity is controlled by temperature in geothermal environments.

    PubMed

    Sharp, Christine E; Brady, Allyson L; Sharp, Glen H; Grasby, Stephen E; Stott, Matthew B; Dunfield, Peter F

    2014-06-01

    Over 200 years ago Alexander von Humboldt (1808) observed that plant and animal diversity peaks at tropical latitudes and decreases toward the poles, a trend he attributed to more favorable temperatures in the tropics. Studies to date suggest that this temperature-diversity gradient is weak or nonexistent for Bacteria and Archaea. To test the impacts of temperature as well as pH on bacterial and archaeal diversity, we performed pyrotag sequencing of 16S rRNA genes retrieved from 165 soil, sediment and biomat samples of 36 geothermal areas in Canada and New Zealand, covering a temperature range of 7.5-99 °C and a pH range of 1.8-9.0. This represents the widest ranges of temperature and pH yet examined in a single microbial diversity study. Species richness and diversity indices were strongly correlated to temperature, with R(2) values up to 0.62 for neutral-alkaline springs. The distributions were unimodal, with peak diversity at 24 °C and decreasing diversity at higher and lower temperature extremes. There was also a significant pH effect on diversity; however, in contrast to previous studies of soil microbial diversity, pH explained less of the variability (13-20%) than temperature in the geothermal samples. No correlation was observed between diversity values and latitude from the equator, and we therefore infer a direct temperature effect in our data set. These results demonstrate that temperature exerts a strong control on microbial diversity when considered over most of the temperature range within which life is possible.

  16. Synchronous compartment temperature control and apparatus for refrigeration with reduced energy consumption

    DOEpatents

    Gomes, Alberto Regio; Keres, Stephen L.; Kuehl, Stephen J.; Litch, Andrew D.; Richmond, Peter J.; Wu, Guolian

    2015-09-22

    A refrigerator appliance configuration, and associated methods of operation, for an appliance with a controller, a condenser, at least one evaporator, a compressor, and two refrigeration compartments. The configuration may be equipped with a variable-speed or variable-capacity compressor, variable speed evaporator or compartment fans, a damper and/or a dual-temperature evaporator with a valve system to control flow of refrigerant through one or more pressure reduction devices. The controller, by operation of the compressor, fans, damper and/or valve system, depending on the appliance configuration, controls the cooling rate in one or both compartments to synchronize, alternating cycles of cooling the compartments to their set point temperatures.

  17. 46 CFR 154.1836 - Vapor venting as a means of cargo tank pressure and temperature control.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... temperature control. 154.1836 Section 154.1836 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY... LIQUEFIED GASES Operations § 154.1836 Vapor venting as a means of cargo tank pressure and temperature... cargo pressure and temperature control system under §§ 154.701 through 154.709 is operating and...

  18. 46 CFR 154.1836 - Vapor venting as a means of cargo tank pressure and temperature control.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... temperature control. 154.1836 Section 154.1836 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY... LIQUEFIED GASES Operations § 154.1836 Vapor venting as a means of cargo tank pressure and temperature... cargo pressure and temperature control system under §§ 154.701 through 154.709 is operating and...

  19. 46 CFR 154.1836 - Vapor venting as a means of cargo tank pressure and temperature control.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... temperature control. 154.1836 Section 154.1836 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY... LIQUEFIED GASES Operations § 154.1836 Vapor venting as a means of cargo tank pressure and temperature... cargo pressure and temperature control system under §§ 154.701 through 154.709 is operating and...

  20. 46 CFR 154.1836 - Vapor venting as a means of cargo tank pressure and temperature control.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... temperature control. 154.1836 Section 154.1836 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY... LIQUEFIED GASES Operations § 154.1836 Vapor venting as a means of cargo tank pressure and temperature... cargo pressure and temperature control system under §§ 154.701 through 154.709 is operating and...