Ambient temperature recorder

A temperature data recorder, designated the Ambient Temperature Recorder (ATR-4), was developed at NASA Ames Research Center to meet particular requirements for space life sciences experiments. The small, self-contained, four-channel, battery-powered device records 32 kilobytes of temperature data over a range of -40 to +60 C at four sampling intervals ranging from 1.875 to 15 minutes. Data is stored in its internal electronic memory for later readout by a personal computer

Air Temperature Comparison between the MMTS and the USCRN Temperature Systems

A new U.S. Climate Reference Network (USCRN) was officially and nationally commissioned by the Department of Commerce and the National Oceanic and Atmospheric Administration in 2004. During a 1-yr side-by-side field comparison of USCRN temperatures and temperatures measured by a maximum-minimum temperature system (MMTS), analyses of hourly data show that the MMTS temperature performed with biases: 1) a systematic bias–ambient-temperature-dependent bias and 2) an ambient-solar-radiation- and ambient-wind- speed-dependent bias. Magnitudes of these two biases ranged from a few tenths of a degree to over 1C compared to the USCRN temperatures. The hourly average temperatures for the USCRN were the dependent variables in the development of two statistical models that remove the biases due to ambient temperature, ambient solar radiation, and ambient wind speed in the MMTS. The model performance was examined, and the results show that the adjusted MMTS data were substantially improved with respect to both systematic bias and the bias associated with ambient solar radiation and ambient wind speed. In addition, the results indicate that the historical temperature datasets prior to the MMTS era need to be further investigated to produce long-term homogenous times series of area-average temperature

Effect of microstructural evolution on magnetic properties of Ni thin films

Copyright © Indian Academy of Sciences.The magnetic properties of Ni thin films, in the range 20–500 nm, at the crystalline-nanocrystalline interface are reported. The effect of thickness, substrate and substrate temperature has been studied. For the films deposited at ambient temperatures on borosilicate glass substrates, the crystallite size, coercive field and magnetization energy density first increase and achieve a maximum at a critical value of thickness and decrease thereafter. At a thickness of 50 nm, the films deposited at ambient temperature onto borosilicate glass, MgO and silicon do not exhibit long-range order but are magnetic as is evident from the non-zero coercive field and magnetization energy. Phase contrast microscopy revealed that the grain sizes increase from a value of 30–50 nm at ambient temperature to 120–150 nm at 503 K and remain approximately constant in this range up to 593 K. The existence of grain boundary walls of width 30–50 nm is demonstrated using phase contrast images. The grain boundary area also stagnates at higher substrate temperature. There is pronounced shape anisotropy as evidenced by the increased aspect ratio of the grains as a function of substrate temperature. Nickel thin films of 50 nm show the absence of long-range crystalline order at ambient temperature growth conditions and a preferred [111] orientation at higher substrate temperatures. Thin films are found to be thermally relaxed at elevated deposition temperature and having large compressive strain at ambient temperature. This transition from nanocrystalline to crystalline order causes a peak in the coercive field in the region of transition as a function of thickness and substrate temperature. The saturation magnetization on the other hand increases with increase in substrate temperature.University Grants Commission for Centre of Advanced Studies in Physic

Rechargeable ambient temperature lithium cells

The cycling performance of a secondary lithium cell with a 2-methyl THF lithium hectofluorarsenate electrolyte is discussed. Stripping efficiency, dendritization, passivation on standing, and discharge efficiency are considered

Ambient-temperature co-oxidation catalysts

Oxidation catalysts which operate at ambient temperature were developed for the recombination of carbon monoxide (CO) and oxygen (O2) dissociation products which are formed during carbon dioxide (CO2) laser operation. Recombination of these products to regenerate CO2 allows continuous operation of CO2 lasers in a closed cycle mode. Development of these catalyst materials provides enabling technology for the operation of such lasers from space platforms or in ground based facilities without constant gas consumption required for continuous open cycle operation. Such catalysts also have other applications in various areas outside the laser community for removal of CO from other closed environments such as indoor air and as an ambient temperature catalytic converter for control of auto emissions

Ambient temperature catalyst for hydrogen ignition

Low cost, ambient temperature catalyst for reacting hydrogen gas with air in a catalytic cell near the point of evolution at a controlled rate is announced

Transport and structural study of pressure-induced magnetic states in Nd0.55Sr0.45MnO3 and Nd0.5Sr0.5MnO3

Pressure effects on the electron transport and structure of Nd1-xSrxMnO3 (x = 0.45, 0.5) were investigated in the range from ambient to ~6 GPa. In Nd0.55Sr0.45MnO3, the low-temperature ferromagnetic metallic state is suppressed and a low temperature insulating state is induced by pressure. In Nd0.5Sr0.5MnO3, the CE-type antiferromagnetic charge-ordering state is suppressed by pressure. Under pressure, both samples have a similar electron transport behavior although their ambient ground states are much different. It is surmised that pressure induces an A-type antiferromagnetic state at low temperature in both compounds

Behavioral thermoregulation in the American lobster Homarus americanus

It is generally accepted that water temperature has a strong influence on the behavior of the American lobster Homarus americanus. However, there is surprisingly little behavioral evidence to support this view. To haracterize the behavioral responses of lobsters to thermal gradients, three different experiments were conducted. In the first, 40 lobsters acclimated to summer water temperatures (summer-acclimated, 15.5±0.2 °C, mean ±S.E.M.) were placed individually in an experimental shelter, and the temperature in the shelter was gradually raised until the lobster moved out. Lobsters avoided water warmer than 23.5±0.4 °C, which was an increase of 8.0±0.4 °C from ambient summer temperatures. When this experiment was repeated with lobsters acclimated to winter temperatures (winter-acclimated, 4.3±0.1 °C), the lobsters (N=30) did not find temperature increases of the same magnitude (∆T=8.0±0.4 °C) aversive. The second experiment was designed to allow individual summer-acclimated lobsters (N=22) to select one of five shelters, ranging in temperature from 8.5 to 25.5 °C. After 24 h, 68 % of the lobsters occupied the 12.5 °C shelter, which was slightly above the ambient temperature (approximately 11 °C). In a similar experiment, winter-acclimated lobsters (N=30) were given a choice between two shelters, one at ambient temperature (4.6±0.2 °C) and one at a higher temperature (9.7±0.3 °C). Winter-acclimated lobsters showed a strong preference (90 %) for the heated shelter. In the final experiment, summer-acclimated lobsters (N=9) were allowed to move freely in a tank having a thermal gradient of approximately 10 °C from one end to the other. Lobsters preferred a thermal niche of 16.5±0.4 °C and avoided water that was warmer than 19 °C or colder than 13 °C. When standardized for acclimation temperature, lobsters preferred water 1.2±0.4 °C above their previous ambient temperature. Collectively, the results of these studies indicate that lobsters are capable of sensing water temperature and use this information to thermoregulate behaviorally. The implications of these findings for lobster behavior and distribution in their natural habitat are discussed

Investigation on efficiency improvement of a Kalina cycle by sliding condensation pressure method

Conventional Kalina cycle-based geothermal power plants are designed with a fixed working point determined by the local maximum ambient temperature during the year. A previous study indicated that the plant’s annual average thermal efficiency would be improved if the ammonia mass fraction of the Kalina cycle could be tuned to adapt to the ambient conditions. In this paper, another sliding condensation pressure method is investigated. A theoretical model is set up and then a numerical program is developed to analyze the cycle performance. The condensation pressure adjustment in accordance to the changing ambient temperature has been numerically demonstrated under various ammonia-water mixture concentrations. The results indicate that the Kalina cycle using sliding condensation pressure method can achieve much better annual average thermal efficiency than a conventional Kalina cycle through matching the cycle with the changing ambient temperature via controlling condensation pressure. Furthermore, the sliding condensation pressure method is compared with the composition tuning method. The results show that the annual average efficiency improvement of the sliding condensation pressure method is higher than that of the composition tuning method