Sand Distribution In Central Fergana

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.

Model of heat diffusion in the outer crust of bursting neutron stars

ABSTRACT We study heat diffusion after an energy release in a deep spherical layer of the outer neutron star crust (107 ≲ ρ ≲ 4 × 1011 g cm−3). We demonstrate that this layer possesses specific heat-accumulating properties, absorbing heat and directing it mostly inside the star. It can absorb up to ∼1043–1044 erg due to its high heat capacity, until its temperature exceeds T ∼ 3 × 109 K and triggers a rapid neutrino cooling. A warm layer (T ∼ 108–3 × 109 K) can serve as a good heat reservoir, which is thermally decoupled from the inner crust and the stellar core for a few months. We present a toy model to explore the heat diffusion within the heat-accumulating layer, and we test this model using numerical simulations. We formulate some generic features of the heat propagation that can be useful, for instance, for the interpretation of superbursts in accreting neutron stars. We present a self-similar analysis of late afterglow after such superbursts, which can be helpful to estimate properties of bursting stars.

Polymeric Reaction Molding of Biocompatible Materials: Lessons Learned

Polymeric materials are often used as structural binders for biomedical applications. The mechanical properties of the material strongly depend on the fabrication process. To this end, we illustrate a set of casting methods for the production of samples to be tested via destructive methods. The curing process of the artifact was controlled during fabrication, and the molds were also made of polymeric materials. The fabrication of molds is illustrated where particular emphasis is posed on the manufacturing and testing of silicone molds using off-the-shelf material. Cyanoacrylate (CA), Epoxy resin (EP) and Methacrylate ester monomers (MEMs) artifacts have been fabricated using said molds. Of the aforementioned resins, MEMs are a class of thermosetting biocompatible polymers in which fabrication is especially problematic because of the very narrow temperature window at which the monomers polymerize. This research analyzes the casting process of curable materials highlighting the setbacks of using plastic-based molds. Among the cast based manufacturing techniques, specific focus was given to the case where MEMs is made to polymerize in a silicone mold controlling the temperature of the environment. The thermal properties that the silicone-based molds require for the appropriate curing of the polymer are analyzed. It was found that due to the very high heat capacity of silicone, the regulation of the temperature within the mold is difficult often exciding the boiling point of the casted resin.

A Novel Design of Liquid Volumetric Plated Cavity Receiver for Central Tower Systems

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.

0015 Manipulating Body Temperature: Effects on Sleep in Postmenopausal Women

Introduction A decline in sleep quality and reduction in slow wave sleep (SWS) and slow wave activity (SWA) are common in older adults. Prior studies have shown that manipulating body temperature during sleep can increase SWS/SWA. The aim of this study was to determine the effects of manipulation of body temperatures during sleep, using a high heat capacity mattress, on SWS/SWA and heart rate variability in post-menopausal women. Methods Twenty-four healthy postmenopausal women between 40–75 years of age (mean age 62.4 ± 8.2 years, mean BMI 25.4 ± 3.5 kg/m2) were randomized in a single-blind, counterbalanced, cross-over manner to sleep on either a high heat capacity mattress (HHCM) or a low heat capacity mattress(LHCM) a week apart. Sleep was recorded using polysomnography during an 8-hour sleep opportunity. Core and peripheral temperatures were recorded using Equivital and ibutton respectively. Results In comparison to the LHCM, sleep on HHCM exhibited a selective increase in SWS (average increase in Stage N3 of 9.6 minutes (2.1%), p = 0.04) and in slow oscillatory activity (0.5-1Hz) in the first NREM/REM cycle (p=0.04). In addition, the HHCM induced a greater reduction in core body temperature (p=0.002), and delayed the increase in mattress surface temperature (maximal difference LHCM-HHCM: 4.66±0.17°C). Average heart rate was 2.7 beats/minute lower across the night on the HHCM compared to the LHCM (p=0.001). Conclusion The results of this study indicate that manipulation of body temperature during sleep may be a useful approach to enhance SWS sleep and cardiovascular function in postmenopausal women. Support Technogel

ENERGY AND FEASIBILITY ANALYSIS OF APPLYING BIO-BASED PHASE CHANGE MATERIALS TO BUILDINGS IN EAST ASIA

ABSTRACT The application of phase change materials (PCMs) in building envelopes can help promote energy efficiency due to its high heat capacity. Our study aimed to provide energy and economic insights for deploying PCM to buildings in eight different regions of East Asia through a series of energy and economic analysis using computer modelling and simulations. The static payback period (SPP) and dynamic payback (DPP) methods were used to evaluate the economic feasibility of applying a PCM at different melting phase temperatures (20°C, 23°C, 25°C, 27°C and 29°C). Results show that the proper choice of a PCM melting temperature is a key factor to improve the performance of the PCM applied to buildings. A melting phase temperature of 29°C achieved the highest economic feasibility in Seoul, Tokyo; Pyongyang; Beijing; and Ulaanbaatar and a melting temperature of 23°C in Hong Kong had the highest economic feasibility. Overall, the combined economic and energy analysis presented in this study can play an important role in improving the energy and economic feasibility of PCM in buildings.

The integration of selected technology to energy activated ETICS - theoretical approach

The main goal of this study is to develop the new external thermal insulation composite system (ETICS) by integration of flexible photovoltaic (FPV) and encapsulated phase change materials (PCM). This work is the first step of the international project En-ActivETICS and concerns mainly material selection and systems integration issues. The paper presents a complete solution of façade component which integrates thermal insulation, heat storage and electricity generation - En-ActivETICS that combines ETICS technology with a self-supporting flexible photovoltaic elements. This system will be applicable for both masonry or concrete constructions and it is a new step in the development of building facade technology allowing to achieve a component classified to the group of functional material. In the paper, the formulation of basic principles of En-ActivETICS as well as an overview of existing materials and technologies is presented. Finally, the initial concept of the system is described. The main features of that system is using an elastic, high heat capacity and frost resistant adhesive joining flexible PV with thermal insulation.

Effects of sleep on a high-heat capacity mattress on sleep stages, EEG power spectra, cardiac interbeat intervals and body temperatures in healthy middle-aged men‡

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.

Inverse Contrast in Non-Destructive Materials Research by Using Active Thermography

Background: it is undesirable for defects to occur in building partitions and units. There is a need to develop and improve research techniques for locating such defects, especially non-destructive techniques for active thermography. The aim of the experiment was to explore the possibility of using active thermography for testing large-sized building units (with high heat capacity) in order to locate material inclusions. Methods: as part of the experiment, two building partition models—one made of gypsum board (GB) and another made of oriented strand board (OSB)—were built. Three material inclusions (styrofoam, granite, and steel), considerably differing in their thermal parameters, were placed in each of the partitions. A 7.2 kW infrared radiator was used for thermally exciting (heating) the investigated element for 30 min. The distribution of the temperature field was studied on both sides of the partition for a few hours. Results: using the proposed investigative method, one can detect defects in building partitions under at least 22 mm of thick cladding. At a later cooling down phase, inverse temperature contrasts were found to occur—the defects, which at the beginning of cooling down were visible as warmer areas, at a later phase of cooling down are perceived as cooler areas, and vice versa (on the same front surface). In the transmission mode, the defects are always visible as areas warmer than defect-free areas. Moreover, a quantitative (defect location depth) analysis with an accuracy of up to 10% was carried out using the Echo Defect Shape method. Conclusions: active thermography can be used in construction for non-destructive materials testing. When the recording of thermograms is conducted for an appropriate length of time, inverse contrasts can be observed (on the same front surface).

Development of core–sheath structured smart nanofibers by coaxial electrospinning for thermo-regulated textiles

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