scholarly journals ERGONOMIC PROPERTIES OF THE SEMI-FINISHED SHORT HAIRY RABBIT FUR PRODUCT

2020 ◽  
Vol 49 (3) ◽  
pp. 3-5
Author(s):  
О. А. Strepetova ◽  
M. V. Gorbacheva ◽  
T. V. Reusova
Keyword(s):  
Moisture Content ◽  
Thermal Resistance ◽  
Thermal Protection ◽  
Total Thermal Resistance ◽  
Content Index ◽  
Rex Rabbit ◽  
Skin Samples

The article is dedicated to the study of the ergonomic properties of the semi-finished short-haired rabbit fur, which determine the technological possibilities of fur. It is shown that the semi-finished rabbit of rex breed of colour castor and chinchilla has equal resistance to moisture when wet, which is indicated by the moisture content index. When testing hygroscopicity, it is established that the skin samples with hair are less hydrophilic than those without it; by 12,5 %, in the rabbit skins of the rex castor breed, and by 13,8 %, in the skins of the rabbit of rex chinchilla breed. The total thermal resistance of a semi-finished rex rabbit product exceeds the value of the feature of 0,210 m2 ·ºC/W, which makes it one of the group of semi-finished fur products with high thermal protection properties. The established indicators of ergonomic properties of a semi-finished rex rabbit product should be taken into account when choosing semi-finished products and creating furs of different designs and silhouettes.

scholarly journals ТЕРМІЧНИЙ ОПІР ХУТРЯНОГО ОДЯГУ

2021 ◽  
pp. 41-47
Author(s):  
С. І. Мойсеєнко ◽  
С. В. Донченко ◽  
А. І. Кулішова
Keyword(s):  
Thermal Resistance ◽  
Red Fox ◽  
Thermal Protection ◽  
Experimental Studies ◽  
Information Support ◽  
Total Thermal Resistance ◽  
Information Base ◽  
Heat Shielding ◽  
Fur Animals ◽  
Available Information

Improving the process of forecasting thermal protection of clothing by expanding the information base of thermophysical indicators of fur, namely its thermal resistance. Methodology. To achieve this goal, an experimental method has been applied to study the thermal resistance of clothes by indirectly measuring and simulating heat transfer of the human body with the environment at various temperatures without using a climate chamber.Results. The paper analyzes the existing information base for the thermophysical parameters of the fur of diff erent animals, as a result of which it was found that the available information is not suffi cient to predict the thermal protection of clothing. The subject of the study was selected fur animals that are in greatest demand among consumers in Ukraine. Experimental studies of the thermal conductivity of fur vests were carried out as a result of which their thermal resistance was determined. It has been established experimentally that the thermal resistance of the fur of a long-haired rabbit is 0,1 °C m 2 /W more than that of a red fox. As a result of experimental studies, it was found that the total thermal resistance of red fox fur and long-haired rabbit is in the range of 0,471 to 0,559 °C m 2  / W.  For the fi rst time, the thermal resistance of vests made of long-haired rabbit and red fox fur was determined taking into account the anatomical reliefs of the human torso. The existing methodology for determining the thermal resistance of garments on the simulated thermal stand of a human torso (ITSHB) to determine the thermal resistance of fur products has been adapted. Practical signifi cance. Extension of information support for the process of forecasting the heat-shielding properties of fur clothing. Reducing material costs for researching the thermal resistance of fur products.

Combined Microstructure and Heat Transfer Modeling of Carbon Nanotube Thermal Interface Materials1

2016 ◽  
Vol 138 (4) ◽  
Author(s):  
Sridhar Sadasivam ◽  
Stephen L. Hodson ◽  
Matthew R. Maschmann ◽  
Timothy S. Fisher
Keyword(s):  
Heat Transfer ◽  
Thermal Resistance ◽  
Finite Volume ◽  
Pressure Dependence ◽  
Matrix Material ◽  
Three Dimensional ◽  
Coarse Grain ◽  
Total Thermal Resistance ◽  
Thermal Interface ◽  
Cnt Arrays

A microstructure-sensitive thermomechanical simulation framework is developed to predict the mechanical and heat transfer properties of vertically aligned CNT (VACNT) arrays used as thermal interface materials (TIMs). The model addresses the gap between atomistic thermal transport simulations of individual CNTs (carbon nanotubes) and experimental measurements of thermal resistance of CNT arrays at mesoscopic length scales. Energy minimization is performed using a bead–spring coarse-grain model to obtain the microstructure of the CNT array as a function of the applied load. The microstructures obtained from the coarse-grain simulations are used as inputs to a finite volume solver that solves one-dimensional and three-dimensional Fourier heat conduction in the CNTs and filler matrix, respectively. Predictions from the finite volume solver are fitted to experimental data on the total thermal resistance of CNT arrays to obtain an individual CNT thermal conductivity of 12 W m−1 K−1 and CNT–substrate contact conductance of 7 × 107 W m−2 K−1. The results also indicate that the thermal resistance of the CNT array shows a weak dependence on the CNT–CNT contact resistance. Embedding the CNT array in wax is found to reduce the total thermal resistance of the array by almost 50%, and the pressure dependence of thermal resistance nearly vanishes when a matrix material is introduced. Detailed microstructural information such as the topology of CNT–substrate contacts and the pressure dependence of CNT–opposing substrate contact area are also reported.

Investigation of the Influence of Technological Factors on the Characteristics of Flexible Non-Adhesive Foil Dielectrics

2020 ◽  
Vol 25 (6) ◽  
pp. 505-516
Author(s):  
A.V. Vorobyov ◽  
◽  
V.D. Zhora ◽  
N.I. Plis ◽  
S.P. Timoshenkov ◽  
...  
Keyword(s):  
Thermal Resistance ◽  
Electrical Characteristics ◽  
Traditional Use ◽  
Total Thermal Resistance ◽  
Technological Factors ◽  
High Adhesion ◽  
Negative Effect ◽  
The Stability ◽  
Thermal Resistors ◽  
The Given

Currently, the traditional use of varnish-foil dielectrics for manufacturing resistors, resistive assemblies and heating elements has been supplemented by their application in production of thermal resistors, the membranes of acoustic and photoelectric transformers. As a rule, the non-adhesive foil dielectrics sustain the affect of high temperatures, permit to significantly increase the density of elements and have better quality characteristics, because the adhesives have negative effect upon the electrical characteristics of the materials, manufactured with their application. Also, the adhesives have comparatively low thermal resistance, which manifests on the total thermal resistance of foil dielectric and the items manufactured on it, especially in case when as a base polyimide is used. In the paper the flexible foil dielectrics for electronic equipment and their manufacturing technology have been considered. The advantages of the non-adhesive foil dielectrics with complete imidization of the polymer base have been shown. The technology of manufacturing the varnish-foil dielectrics, used in manufacturing highly reliable microcircuits of modification 2 and of highly technological membranes of acoustic transformers, has been developed. The polyimide base of the dielectrics has high adhesion to foil and the guaranteed uniformity of the imidization extent 95-100 %. This provides the stability of technological conditions in the process of manufacturing the items from the given materials, as well as an increase of the storage life of the varnish-foil dielectrics up to 12 months.

Double-Sided Transferred Carbon Nanotube Arrays for Improved Thermal Interface Materials

2015 ◽  
Vol 137 (3) ◽  
Author(s):  
Andrew J. McNamara ◽  
Yogendra Joshi ◽  
Zhuomin Zhang ◽  
Kyoung-sik Moon ◽  
Ziyin Lin ◽  
...  
Keyword(s):  
Carbon Nanotube ◽  
Thermal Resistance ◽  
Prolonged Exposure ◽  
Silicon Substrates ◽  
Thermal Interface Materials ◽  
Total Thermal Resistance ◽  
Thermal Interface ◽  
Ir Microscopy ◽  
Vertically Aligned ◽  
Interface Materials

Recently, much attention has been given to reducing the thermal resistance attributed to thermal interface materials (TIMs) in electronic devices, which contribute significantly to the overall package thermal resistance. Thermal transport measured experimentally through several vertically aligned carbon nanotube (VACNT) array TIMs anchored to copper and silicon substrates is considered. A steady-state infrared (IR) microscopy experimental setup was designed and utilized to measure the cross-plane total thermal resistance of VACNT TIMs. Overall thermal resistance for the anchored arrays ranged from 4 to 50 mm2 KW-1. These values are comparable to the best current TIMs used for microelectronic packaging. Furthermore, thermal stability after prolonged exposure to a high-temperature environment and thermal cycling tests shows limited deterioration for an array anchored using a silver-loaded thermal conductive adhesive (TCA).

scholarly journals Thermal Protection and Microclimate of SOLAS Approved Lifeboats

2010 ◽  
Author(s):  
Lawrence Mak ◽  
Andrew Kuczora ◽  
Brian Farnworth ◽  
Rob Brown ◽  
Michel B. DuCharme
Keyword(s):  
Thermal Resistance ◽  
Thermal Protection ◽  
Heat Rate ◽  
Offshore Structures ◽  
Ventilation Rate ◽  
The Arctic ◽  
Thermal Manikin ◽  
High Concentration ◽  
Marine Vehicles ◽  
Heat And Cold Stress

Lifeboats are used as an evacuation system on a wide variety of offshore structures and marine vehicles. Currently, International Maritime Organization (IMO) Lifesaving Appliances (LSA) Code does not specify thermal protection and ventilation criteria for lifeboats. A test program was conducted to assess the system thermal protection and microclimate of SOLAS approved lifeboats for the Arctic environment. Some of the research findings of the first phase experiments are reported in this paper. In conducting experiments with a 72-person SOLAS approved lifeboat, the study found that the lifeboat only had a ventilation rate of 2 litres per second with vents open only, which may not be adequate. Inadequate ventilation will result in high concentration of carbon dioxide, causing headache, dizziness, restlessness, breathing difficulty, sweating, and increased heat rate, cardiac output and blood pressure. All of these may adversely affect lifeboat occupants in performing survival tasks. Using a thermal manikin, only slight decrease in thermal resistance (less than 10%) was observed in many test cases, when active ventilation was implemented (ventilation rate of 31 and 42 litres per second) and when side hatches were opened (ventilation rate of 95 litres per second). This suggests that reasonable increase in ventilation rate may be implemented without trading off much in thermal protection. However, a more noticeable decreases in thermal resistance (15% to over 30%) were observed when clothing was wet. This suggests it is critical to stay dry. A mathematical model was also developed to assess heat and cold stress of lifeboat occupants under different environment, lifeboat, occupant and ventilation conditions.

Thermal resistance of polyurethane-coated knitted fabrics before and after weathering

2014 ◽  
Vol 84 (19) ◽  
pp. 2015-2025 ◽  
Author(s):  
Vesna Marija Potočić Matković ◽  
Ivana Salopek Čubrić ◽  
Zenun Skenderi
Keyword(s):  
Thermal Resistance ◽  
Thermal Protection ◽  
Winter Season ◽  
Outdoor Exposure ◽  
Woven Fabrics ◽  
Knitted Fabric ◽  
Knitted Fabrics ◽  
Coated Fabric ◽  
Before And After ◽  
Coated Fabrics

Polyurethane-coated knitted fabrics are of interest because they exhibit several positive properties, they are more stretchable, elastic and comfortable than coated woven fabrics and yet they are little studied. Information of weather durability, as well as thermal properties, is essential to ensure thermal protection for textile materials intended for outdoor use. In the presented research, a series of coated knitted fabrics for protective clothing were developed and exposed to weathering in summer and winter seasons. After three months of outdoor exposure, thermal resistance of all the tested materials decreased by 13% after the summer season and 25% after the winter season. A very good correlation of knitted fabric mass per unit area and thermal resistance of knitted fabric, coated fabric and aged coated fabric occurred. The studied materials experienced a partial degradation of the polyurethane layer, which is not related to the deterioration of the knitted substrate. The presented investigation of thermal resistance of coated fabrics and their dependence on the knitted substrate, as well as the influence of environmental conditions, allows the improvement of coated fabrics with the aim of better thermal protection.

Variation of thermal resistance with input current and ambient temperature in low-power SMD LED

2018 ◽  
Vol 35 (1) ◽  
pp. 1-11 ◽  
Author(s):  
Muna E. Raypah ◽  
Dheepan M.K. ◽  
Mutharasu Devarajan ◽  
Shanmugan Subramani ◽  
Fauziah Sulaiman
Keyword(s):  
Low Power ◽  
Thermal Resistance ◽  
Ambient Temperature ◽  
Light Emitting Diode ◽  
Operating Conditions ◽  
Input Current ◽  
Junction Temperature ◽  
Total Thermal Resistance ◽  
Content Type ◽  
Thermal Transient

Purpose Thermal behavior of light-emitting diode (LED) device under different operating conditions must be known to enhance its reliability and efficiency in various applications. The purpose of this study is to report the influence of input current and ambient temperature on thermal resistance of InGaAlP low-power surface-mount device (SMD) LED. Design/methodology/approach Thermal parameters of the LED were measured using thermal transient measurement via Thermal Transient Tester (T3Ster). The experimental results were validated using computational fluid dynamics (CFD) software. Findings As input current increases from 50 to 90 mA at 25°C, the relative increase in LED package (ΔRthJS) and total thermal resistance (ΔRthJA) is about 10 and 4 per cent, respectively. In addition, at 50 mA and ambient temperature from 25 to 65°C, the ΔRthJS and ΔRthJA are roughly 28 and 22 per cent, respectively. A good agreement between simulation and experiment results of junction temperature. Originality/value Most of previous studies have focused on thermal management of high-power LEDs. There were no studies on thermal analysis of low-power SMD LED so far. This work will help in predicting the thermal performance of low-power LEDs in solid-state lighting applications.

Optimization Design the Configuration Sizes of Multi-Layer Rectangle Micro-Channel Heat Sink

2013 ◽  
Vol 444-445 ◽  
pp. 1101-1106
Author(s):  
Li Feng Wang ◽  
Bao Dong Shao ◽  
He Ming Cheng ◽  
Ying He
Keyword(s):  
Pressure Drop ◽  
Thermal Resistance ◽  
Heat Sink ◽  
Optimization Design ◽  
High Heat ◽  
Micro Channel ◽  
Compact Structure ◽  
Total Thermal Resistance ◽  
High Heat Transfer ◽  
High Heat Transfer Coefficient

The configuration sizes of multi-layer rectangle micro-channel heat sink are optimized, which has been widely used to cool electronic chip for its high heat transfer coefficient and compact structure. Taking the thermal resistance and the pressure drop as goal functions, a binary-objective optimization model was proposed for the multi-layer rectangle micro-channel heat sink based on Sequential Quadratic Programming (SQP) method. The number of optimized micro-channel in width n1 and that in height n2 are 24 and 3, the width of optimized micro-channel Wc and fin Wf are 360 and 55μm, the height of optimized micro-channel Hc is 1000μm, and the corresponding total thermal resistance of the whole micro-channel heat sink is 1.5429 °C/W. The corresponding pressure drop is about 2.3454 Pa. When the velocity of liquid is larger than 0.3 m/s, the effect of change of velocity of liquid on the thermal resistance and pressure drop can be neglected.

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