Insulation Sheath Materials for Cold Preservation

2019 ◽  
Vol 974 ◽  
pp. 452-457
Author(s):  
Alexey D. Zhukov ◽  
Karapet A. Ter-Zakaryan ◽  
Ekaterina Yu. Bobrova ◽  
Anaton S. Pilipenko
Keyword(s):  
Tensile Strength ◽  
Low Temperatures ◽  
Energy Savings ◽  
Experimental Studies ◽  
Functional Results ◽  
Frame Structures ◽  
Sports Facilities ◽  
Cold Preservation ◽  
Ski Resorts ◽  
Lock Joint

The article studies one of the aspects of the heat-insulating multifunctional shells use - the cold preservation. Such task is relevant for cold storages, workshops and warehouses, in which low temperatures constant maintenance is necessary, for sports facilities (for example, ice rinks and ski facilities). In all cases of application, the main goal is to achieve the economic efficiency, which is expressed in functional results (preservation of the material that breaks down at positive temperatures) and in energy savings. The use of polyethylene-based shells, which are connected by a lock joint, is substantiated. The experimental studies results of the material given in the article shows that in terms of resistance to low and alternating temperatures, operational durability, tensile strength and water absorption, this material and insulating shells based on it are quite applicable for insulation of cold-saving objects. The experience of using heat, vapor and moisture insulating shells based on polyethylene foam with the equipment of frameless and frame structures, sports facilities, as well as for the preservation of snow at ski resorts is also provided in the article.

Effect of Wood Filler Concentration on Physical and Mechanical Properties of PLA-Based Composites

2021 ◽  
Vol 887 ◽  
pp. 110-115
Author(s):  
G.A. Sabirova ◽  
R.R. Safin ◽  
N.R. Galyavetdinov
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Elastic Modulus ◽  
Composite Materials ◽  
Impact Strength ◽  
Wood Flour ◽  
Experimental Studies ◽  
Physical And Mechanical Properties ◽  
Filler Concentration ◽  
High Concentration

This paper presents the findings of experimental studies of the physical and mechanical properties of wood-filled composites based on polylactide (PLA) and vegetable filler in the form of wood flour (WF) thermally modified at 200-240 °C. It also reveals the dependence of the tensile strength, impact strength, bending elastic modulus, and density of composites on the amount of wood filler and the temperature of its thermal pre-modification. We established that an increase in the concentration of the introduced filler and the degree of its heat treatment results in a decrease of the tensile strength, impact strength and density of composite materials, while with a lower binder content, thermal modification at 200 °C has a positive effect on bending elastic modulus. We also found that 40 % content of a wood filler heated to 200 °C is sufficient to maintain relatively high physical and mechanical properties of composite materials. With a higher content of a wood filler, the cost can be reduced but the quality of products made of this material may significantly deteriorate. However, depending on the application and the life cycle of this product, it is possible to develop a formulation that includes a high concentration of filler.

Research of the Mechanical Properties of the Filament from the Percentage of Filling when Prototyping Machine Parts

2021 ◽  
Vol 410 ◽  
pp. 617-623
Author(s):  
Elena N. Gryadynova ◽  
Andrey V. Gorin ◽  
Alexey Yu. Rodichev
Keyword(s):  
Tensile Strength ◽  
Tensile Testing ◽  
Testing Machine ◽  
Experimental Studies ◽  
Relative Deformation ◽  
Strain Diagram ◽  
Experimental Sample ◽  
Tensile Testing Machine ◽  
Machine Parts ◽  
Fisher’S Criterion

The article contains the analysis of thermoplastics used in prototyping machine parts. We used several types of experimental samples with different filling percentages. The equipment on which the experimental studies were carried out is shown. During the experiment, a specialized tensile testing machine was used. The experimental samples were installed in the developed centering device. Normal conditions were observed during the tests. The results of an experimental tensile study of PLA-plastic specimens are presented. The typical stress-strain diagram of an experimental sample is described, which describes the dependence of stress on relative deformation. An equation of the linear dependence of the tensile strength on the percentage of filament filling has been compiled, which makes it possible to determine the tensile strength of the product at any percentage of the filling of the plastic filament. The assessment is adequately verified by Fisher's criterion. Recommendations for filament filling in prototyping machine parts are given.

scholarly journals Determination of Direct Tensile Strength Values of Rock Materials by a New Test Method of Drilled Disc Tension

2019 ◽  
Author(s):  
Eren Komurlu ◽  
Serhat Demir
Keyword(s):  
Tensile Strength ◽  
Experimental Studies ◽  
Test Method ◽  
Uniaxial Tensile ◽  
Direct Tension ◽  
Rock Materials ◽  
Uniaxial Tensile Stress ◽  
Direct Tensile ◽  
Drill Holes ◽  
Direct Tensile Strength

Use of drilled disc specimens was investigated with both numerical and experimental studies to determine direct tensile strengths of rock materials. A new loading apparatus with rods to insert into the drill holes of discs has been designed and manufactured to supply tension by using the compression test presses. In addition to the use of popular compressive presses for direct tension, elimination of the gluing in the standard direct tensile strength test method is a significant advantage to make possible both hard and soft rocks to be tested. The Brazilian test discs with the diameter of NX size and length to diameter ratio of 0.5 were used in tests. Different loading apparatus designs were analyzed and ideal angle of contact between rock and the loading rods was assessed to be 50° within various choices investigated in this study. The drilled discs were determined to fail due to the crack initiation under the condition of uniaxial tensile stress distribution at sidewalls of the hole. In addition to the drilled disc tension test, standard direct tensile strength tests were also carried out to take as reference and compare the results obtained from different methods. According to the results of both numerical and experimental studies, an equation was suggested to determine uniaxial tensile strengths of drilled disc specimens with 20 mm hole diameter and the contact angle of 50°.

Decreased storage stability of creatine kinase in a cardiac reperfusion solution

1990 ◽  
Vol 36 (5) ◽  
pp. 778-780 ◽  
Author(s):  
G Dunphy ◽  
D Ely
Keyword(s):  
Creatine Kinase ◽  
Low Temperatures ◽  
Storage Stability ◽  
Frozen Storage ◽  
Cellular Damage ◽  
Prolonged Storage ◽  
Cold Preservation ◽  
Rat Hearts ◽  
The Stability ◽  
Storage Temperatures

Abstract Creatine kinase (CK; EC 2.7.3.2) has been used as an indicator of myocardial cellular damage. In this study we used a Krebs-Henseleit (KH) solution to reperfuse isolated rat hearts after 24 h of cold preservation and collected the KH reperfusate for assay of CK to assess cellular damage. We wanted to determine the stability of CK in the KH solution at different cold-storage temperatures and albumin concentrations. CK activity (mean +/- SEM) after one week of refrigeration (5 degrees C) was 93% +/- 1% of control values, whereas CK activity in nitrogen-frozen (-200 degrees C) samples was only 1.6% +/- 1% of control values, and that in samples frozen at moderately low temperatures (-10 degrees C) was 63% +/- 1% of control values. To enhance stability, we added albumin at several concentrations (49, 25, 12, and 6 g/L) to reperfusion collections in which CK had been previously determined. Specimens were frozen (-10 degrees C), then re-analyzed for CK weekly for three weeks. CK activity was maintained (100% +/- 5%) only in samples containing 25 g/L or more albumin. These data suggest that refrigeration (5 degrees C) for one week maintains normal CK activity in KH solution; however, if prolonged storage is necessary, a stabilizer such as albumin (greater than or equal to 25 g/L) will maintain analyte stability in frozen storage (-10 degrees C) for at least three weeks.

scholarly journals Ground-Coupled Natural Circulating Devices (Thermosiphons): A Review of Modeling, Experimental and Development Studies

Inventions ◽  
2019 ◽  
Vol 4 (1) ◽  
pp. 14
Author(s):  
Messaoud Badache ◽  
Zine Aidoun ◽  
Parham Eslami-Nejad ◽  
Daniela Blessent
Keyword(s):  
Heat Transfer ◽  
Heat Exchangers ◽  
Low Temperatures ◽  
Experimental Studies ◽  
Heat Transfer Fluid ◽  
Fluid Circulation ◽  
Ground Heat Exchangers ◽  
Additional Equipment ◽  
Different Types ◽  
Overall Efficiency

Compared to conventional ground heat exchangers that require a separate pump or othermechanical devices to circulate the heat transfer fluid, ground coupled thermosiphons or naturallycirculating ground heat exchangers do not require additional equipment for fluid circulation in theloop. This might lead to a better overall efficiency and much simpler operation. This paper providesa review of the current published literature on the different types of existing ground coupledthermosiphons for use in applications requiring moderate and low temperatures. Effort has beenfocused on their classification according to type, configurations, major designs, and chronologicalyear of apparition. Important technological findings and characteristics are provided in summarytables. Advances are identified in terms of the latest device developments and innovative conceptsof thermosiphon technology used for the heat transfer to and from the soil. Applications arepresented in a novel, well-defined classification in which major ground coupled thermosiphonapplications are categorized in terms of medium and low temperature technologies. Finally,performance evaluation is meticulously discussed in terms of modeling, simulations, parametric,and experimental studies.

scholarly journals Always a price to pay: hibernation at low temperatures comes with a trade-off between energy savings and telomere damage

2019 ◽  
Vol 15 (10) ◽  
pp. 20190466 ◽  
Author(s):  
Julia Nowack ◽  
Iris Tarmann ◽  
Franz Hoelzl ◽  
Steve Smith ◽  
Sylvain Giroud ◽  
...  
Keyword(s):  
Body Temperature ◽  
Low Temperatures ◽  
Energy Demand ◽  
Energy Savings ◽  
High Energy ◽  
Cellular Level ◽  
The Body ◽  
Temperature Differential ◽  
Lower Temperature ◽  
Telomere Dynamics

We experimentally tested the costs of deep torpor at low temperatures by comparing telomere dynamics in two species of rodents hibernating at either 3 or 14°C. Our data show that hibernators kept at the warmer temperature had higher arousal frequencies, but maintained longer telomeres than individuals hibernating at the colder temperature. We suggest that the high-energy demand of frequent arousals is counteracted by a lower temperature differential between torpid and euthermic body temperature and that telomere length is restored during arousals when the body temperature is returned to normothermic values. Taken together, our study shows that hibernation at low body temperatures comes with costs on a cellular level and that hibernators need to actively counterbalance the shortening of telomeres.

Structural Performance Evaluation of Built-Up Stub Steel Column with Various Steel Grades under Concentric Loading

2015 ◽  
Vol 764-765 ◽  
pp. 127-131
Author(s):  
Yang Yang ◽  
Kang Min Lee ◽  
Keun Yeong Oh ◽  
Sung Bin Hong
Keyword(s):  
Tensile Strength ◽  
High Strength Steel ◽  
Local Stability ◽  
Experimental Studies ◽  
High Strength Steels ◽  
High Strength ◽  
Design Criteria ◽  
Stability Criteria ◽  
Steel Grades ◽  
Concentric Loading

The current local stability criteria (KBC2009, AISC2010) are enacted through theoretical and experimental studies of ordinary steels, but the mechanical properties of high strength steels are different from ordinary steels. The high strength steel in the applicability of design criteria should be needed to review because of increasing market demanding for high strength steel in the high-rise and long span buildings. In this study, stub columns of H-shaped and box section with various steel grades subjected to concentric loading were investigated, and these steels were checked to the applicability of current local stability criteria. The difference between the ordinary steel and high strength steel was compared. As a result of comparison with various steel grades, most specimens were satisfied with the design criteria, but some specimens with lower tensile strength were not reached the required strength. It is considered that the uncertainty of material was the higher when the tensile strength of material was the lower.

ChemInform Abstract: Experimental Studies of Gas-Phase Reactions at Extremely Low Temperatures

ChemInform ◽  
2010 ◽  
Vol 26 (28) ◽  
pp. no-no
Author(s):  
B. R. ROWE ◽  
I. R. SIMS ◽  
P. BOCHEREL ◽  
I. W. M. SMITH
Keyword(s):  
Gas Phase ◽  
Low Temperatures ◽  
Experimental Studies ◽  
Gas Phase Reactions
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