scholarly journals Sand Distribution In Central Fergana

Author(s):  
Sanoat Xomdamovna Zokirova ◽  
◽  
Rakhmatillo Fayzullaevich Akbarov ◽  
Sadafxon Mukhammadaminovna Isagaliyeva ◽  
Komila Ravshanovna Xonkeldiyeva ◽  
...  

Sands have a high heat capacity and rapid heat transfer - properties that sharply distinguish them from all other soils and determine the characteristic climatic conditions of sand massifs.

SLEEP ◽  
2019 ◽  
Vol 43 (5) ◽  
Author(s):  
Sebastian Herberger ◽  
Kurt Kräuchi ◽  
Martin Glos ◽  
Katharina Lederer ◽  
Lisa Assmus ◽  
...  

Abstract Study Objectives This study deals with the question whether a slow (non-disturbing) reduction of core body temperature (CBT) during sleep increases sleep stage N3 and EEG slow wave energy (SWE) and leads to a slowing of heart rate in humans. Participants Thirty-two healthy male subjects with a mean ± SD age 46 ± 4 years and body mass index 25.2 ± 1.8 kg/m2. Methods A high-heat capacity mattress (HM) was used to lower body temperatures in sleep and was compared to a conventional low-heat capacity mattress (LM) in a double-blinded fashion. Polysomnography was performed accompanied by measurements of skin-, core body- and mattress surface-temperatures, and heart rate. EEG power spectral analyses were carried out using Fast Fourier Transform. Interbeat intervals were derived from the electrocardiogram. Results The HM led to a larger decline in CBT, mediated through higher heat conduction from the core via the proximal back skin onto the mattress together with reduced heart rate. These effects occurred together with a significant increase in sleep stage N3 and standardized slow wave energy (sSWE, 0.791–4.297 Hz) accumulated in NREM sleep. In the 2nd half of the night sSWE increase was significantly correlated with body temperature changes, for example with CBT decline in the same phase. Conclusions A HM subtly decreases CBT, leading to an increased amount of sleep stage N3 and of sSWE, as well as a slowing of heart rate.


2018 ◽  
Vol 185 ◽  
pp. 23-30 ◽  
Author(s):  
Kurt Kräuchi ◽  
Elisa Fattori ◽  
Alessandra Giordano ◽  
Maria Falbo ◽  
Antonella Iadarola ◽  
...  

2017 ◽  
Vol 2 (7) ◽  
pp. 45
Author(s):  
Fadhil K. Farhan ◽  
Zainab Al-Ramadhan ◽  
Widad A. Abd-Al Hussein

In this study, thermal analysis properties (Heat Transfer) have been studied for UPE-PMMA polymer blend reinforced with x-ZnO where x is (0wt%, 1wt%, 2wt%, 3wt%, 4wt% and 5wt %). Ultrasonic dispersion technique used to prepare the nanocomposites specimens follow with cold casting technique using Teflon molds at standard conditions. C - Thermosensor (TC i) technique was used to measure the heat transfer properties such as; (thermal conductivity, thermal effusivity, thermal diffusivity, heat capacity and thermal resistance). Results show that the values of conductivity, effusivity and diffusivity are increased by succession of weight percentage of fillers. While a heat capacity and thermal resistance results show that the values are decreased progressively by succession of weight percentage of fillers. Scanning electron microscopy was employed to aid interpretation results of thermal analyzer and to show the distribution of nanoparticles in polymer matrix.


2020 ◽  
Vol 143 (1) ◽  
Author(s):  
Om Singh ◽  
Kaustubh Bhatwadekar ◽  
N. G. Kartheek ◽  
Shireesh B. Kedare ◽  
Suneet Singh

Abstract Previously reported studies have shown that the volumetric receivers have lower radiative and convective losses, leading to higher efficiency. However, the conventional volumetric receivers are difficult to use along with the thermal storage systems, owing to the use of air as the heat transfer fluid. Molten salt, having high heat capacity, emerges as a suitable candidate to be employed as the heat transfer fluid and for storing thermal energy in the storage devices. It is challenging to use the molten salt in the conventional volumetric receiver configuration; therefore, a novel design called Liquid Volumetric Plated Cavity Receiver is proposed, where the solar salt is used as heat transfer fluid. It consists of a parallel arrangement of hollow plates in an open cavity. Solar radiation concentrated by the heliostat field is absorbed on the outer surface of the hollow plates. The heat is then taken away by the molten salt flowing inside the hollow plates. The plates are arranged such that the molten salt gets heated up within the volume of the enclosure, effectively mimicking the heating performance of the volumetric receivers. Using an analytical model for heat losses, it is observed that the losses are very sensitive to the aspect ratio of the aperture and depth of the receiver. The effects of receiver inclination, plate orientations, radiation incident at the aperture, and surface emissivity have been investigated as well. The results show that a Liquid Volumetric Plated Cavity Receiver increases the efficiency (by ∼3%) as compared with that of the simple cubic receiver.


RSC Advances ◽  
2019 ◽  
Vol 9 (38) ◽  
pp. 21844-21851 ◽  
Author(s):  
Liqiang Yi ◽  
Yan Wang ◽  
Yini Fang ◽  
Ming Zhang ◽  
Juming Yao ◽  
...  

Fabrication of core–sheath structured smart nanofibers loaded with CsxWO3 by coaxial electrospinning which demonstrate high heat capacity and NIR absorbance.


2018 ◽  
Vol 924 ◽  
pp. 866-870
Author(s):  
Brandon Passmore ◽  
Brice McPherson ◽  
David Simco ◽  
Alex Lostetter

This paper discusses Wolfspeed’s advances in silicon carbide (SiC) power module packaging, focusing on recent developments in advanced power module heat transfer techniques, the integration of pinfin mechanical structures, and the implementation of advanced die attach materials. Heat spreader materials and novel cooling methods suitable for SiC power modules are presented, focusing on the thermal heat transfer properties and a discussion of the design and prototype experimental impacts.


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