Browsing by Subject "Temperature measurement"

Now showing 1 - 6 of 6
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    Uncertainty analysis of cryogenic turbine efficiency
    (Assoc Sci Res, 2000) Kanoglu Mehmet
    A procedure for estimating uncertainty in the hydraulic efficiency of cryogenic turbines is presented. A case study is performed based on the test data from a cryogenic turbine testing facility. The effects of uncertainties in the measurements of temperature, pressure, and generator power on the turbine hydraulic efficiency are studied and the uncertainty in turbine efficiency is estimated to be ±0.20%. About 79% of the uncertainty is determined to come from the uncertainty in generator power measurement. This uncertainty in turbine efficiency is believed to be reasonable and acceptable for the testing of cryogenic turbines.
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    Luminescence as a probe of phase changes in transition metal complexes
    (2005) Can N.; Sozerli-Can S.E.; Townsend P.D.; Yang B.; Atac A.; Peto A.
    Precise determination of phase transitions by x-ray analysis requires doses which can cause lattice damage. An alternative initial probe is feasible with radioluminescence temperature measurements, as the spectra, intensity and luminescence lifetimes can all alter discontinuously at a phase transition. The method reduces the total dose by ̃104. Sensitivity to surface contaminants is also possible, as in the case of powder analysis with X-rays. The success of the method has been demonstrated with two compounds, (a) HgI 2{NC5H4C(O)NH2} and (b) Mn(H 2O)6 (O-C6H4NO2) 2, where transitions were recorded at 120 and 230K for (a) and at 110, 145, 205 and 275K for (b). © 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
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    Spectral analysis for current and temperature measurements in power cables
    (2009) Taskin S.; Seker S.; Karahan M.; Akinci T.C.
    This research aims to detect spectral properties under thermal and current variations for power cables. Therefore, spectral diversities are exposed under current unbalances and different load conditions through the spectral analysis techniques. Also, huge load variations are easily detected from the current signals in the time-frequency plane using the short-time frequency analysis. Hence, this study presents the determination of the frequency characteristics and spectral similarities between the phase currents and thermal variations.
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    A practical approach to predict soil temperature variations for geothermal (ground) heat exchangers applications
    (2013) Ozgener O.; Ozgener L.; Tester J.W.
    The paper aims at improving a model predicting daily soil temperatures depending on depth and time. The thermal behavior of the ground (near the surface) as a function of depth and time is difficult to simulate from one point since there are many parameters such as short term weather variations, seasonal variations, moisture content of soil, and thermal conductivity of soil etc. affecting on the temperature of ground. The main drawback of this manuscript is that it claims that the improved model will provide the researchers with easily accessible predictions of daily soil temperature variations, which were modeled from daily fluctuations in air temperatures using a sinusoidal function of time and depth. Transient heat flow principles were used with assumptions of one dimensional heat flow, homogeneous soil, and constant thermal diffusivity. Measured and predicted soil temperatures at depths 5 cm, 10 cm, 20 cm and 300 cm were compared with experimental field results to validate the accuracy of the current model. For an annual cycle; at depth 5 cm, 10 cm, 20 cm, and 300 cm the average maximum percentage of errors were 10.78%, 10%, 10.26%, and 14.95%, respectively. Soil temperature measurements at 3 m depth were made on the earth to air heat exchanger system (EAHE) installed in the Solar Energy Institute in Ege University, Bornova, Izmir. Daily average soil temperatures at depths 5 cm, 10 cm, and 20 cm were taken from Izmir State Meteorological Station. Finally, we analyzed solar fluctuations on soil temperature as a function of depth from 5 cm to 300 cm, and time, gave soil temperature as a function of time up to 1 year (8760 h) for the following depths z = 50 cm, 100 cm, 300 cm, 500 cm, and 1000 cm. © 2013 Elsevier Ltd. All rights reserved.
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    Passive thermal management of an OLED TV display
    (National Institute of Optoelectronics, 2018) Nil M.; Öztürk Y.; Akgül M.B.; Çatalbaş M.C.; Nil M.
    In this study, passive thermal management of a 15’’ OLED TV display is studied. In addition to the OLED display, the effect of other heat generating electronic components on the device is taken into account. Experimental temperature measurements are conducted on the OLED display. The CFD model of the device is developed in order to be able to predict the temperatures and validated with experimental results. A good agreement is obtained between CFD simulation and experimental measurements. To eliminate hot spots and homogenize the tem perature distribution, heat spreaders like copper and graphite are used and the effects of them are discussed in detail. © 2018, National Institute of Optoelectronics. All rights reserved.
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    Microwave hyperthermia application with bioimplant single slot coaxial antenna design for mouse breast cancer treatment
    (Turkiye Klinikleri, 2022) Görgün A.R.; Baytore C.; Comlekci S.; Tuglu M.I.; Kaya A.
    In this study, a novel animal model for the breast cancer treatment which contains hyperthermia is proposed. For this main purpose a low cost, interstitial, bioimplant antenna by short ended single slot design is proposed to heat the cancerous tissues. Both the theoretical background of the proposed system and the simulation and measurement results of antenna design are presented. An artificial tissue phantom model has been created under laboratory conditions and then the utility of the proposed antenna has been tested on this model. Artificial tissues have been heated by 25W to (41-44 ◦C) in a short time like 25 s. Temperature measurement is performed in real-time and wireless by a digital temperature sensor using an embedded system platform. In addition, the effectuality of the proposed hyperthermia system has been tested by the study on live mice. For this purpose, breast cancer tissues created under laboratory conditions have been transferred to experimental group Balb/c mice to induce breast cancer. According to the results of hyperthermia treatment, the breast cancer has been inhibited by the proposed hyperthermia system. All studies have been animal care with ethics committee approval. All experiments have been repeated three times by at least two observers independently. The results of this study give hope that the breast cancer treatment method using this new antenna could be used in humans in the future. For this, the number of such types of ablation studies using this type of antenna should increase. © TÜBİTAK