scholarly journals Mechanical Properties Of Traditional And Nanofibre Textiles

2015 ◽  
Vol 15 (3) ◽  
pp. 198-206
Author(s):  
Petr Ursíny ◽  
Martin Bílek ◽  
Eva Moučková ◽  
Martina Pokorná ◽  
Petr Tumajer ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Low Degree ◽  
Deformation Properties ◽  
Degree Of Orientation ◽  
New Material ◽  
Plied Yarn ◽  
Dynamic Loading Conditions ◽  
High Degree ◽  
Static And Dynamic Loading

Abstract This study deals with a comparison of mechanical properties of a conventional yarn and a textile from nanofibres. The conventional yarn represents the textile objects with high degree of orientation of fibres and the textile from nanofibres represents the textile objects with low degree of orientation of fibres. The theoretical section is concerned with the issue of internal structure of plied yarn and resulting differences in the orientation and straightening of fibres and in utilisation of deformation properties of fibres in comparison to the referred nano textile. The experimental section describes the manner of realisation of both static and dynamic tests of conventional yarn and strips of nanofibres. The results show differences in the mechanical properties of conventional yarn and textile strip from nanofibres under static and dynamic loading conditions. The processing technology of conventional yarn has been verified in the long term. But textiles from nanofibres are a relatively new material and mechanical properties of the detected differences point out possible problems with their behaviour during standard technological processes.

scholarly journals Experimental Study on the Creep Behavior of Red Sandstone under Low Temperatures

2019 ◽  
Vol 2019 ◽  
pp. 1-9 ◽  
Author(s):  
Yongjun Song ◽  
Leitao Zhang ◽  
Huimin Yang ◽  
Jianxi Ren ◽  
Yongxin Che
Keyword(s):  
Mechanical Properties ◽  
Low Temperature ◽  
Deformation Characteristics ◽  
Red Sandstone ◽  
Rock Samples ◽  
Uniaxial Creep ◽  
Deformation Properties ◽  
Accelerated Creep ◽  
Different Temperatures

In cold regions, the deformation characteristics and long-term mechanical properties of rocks under low-temperature conditions are considerably different from those in other regions. To study the deformation characteristics and long-term mechanical properties of rocks in a low-temperature environment and the effect of different temperatures, we perform a multilevel loading-unloading uniaxial creep test on red sandstone samples and obtain the creep curves at different temperatures (20°C, −10°C, and −20°C). The results demonstrate that the total strain at each temperature can be divided into instantaneous and creep strains; the instantaneous strain includes instantaneous elastic and plastic strains, and the creep strain includes viscoelastic and viscoplastic strains. Temperature has a significant effect on the deformation properties of red sandstone. A decrease in temperature reduces the instantaneous and creep deformations of the rocks at all levels of stress. In addition, a decrease in temperature exponentially attenuates the total creep and viscoplastic strains of the rocks. 0°C is a critical point for the reduction of the total creep and viscoplastic strains of the rocks. When the temperature is greater than 0°C, the total creep and viscoplastic strains of the rocks decrease rapidly and linearly with decrease in temperature; however, when the temperature is less than 0°C, the decrease in the total creep and viscoplastic strains of the rocks is slow. The steady-state creep rate of the rock samples decreases with decrease in temperature, whereas the creep duration increases with decrease in temperature, especially in the case of the accelerated creep stage. The accelerated creep durations of the rock samples S4 (20°C) and S7 (–10°C) are 0.07 h and 0.23 h, respectively.

Anisotropy in Thermal, Electrical and Mechanical Properties of Spin-Coated Polymer Dielectrics

1994 ◽  
Vol 338 ◽  
Author(s):  
Sue Ann Bidstrup ◽  
Thomas C. Hodge ◽  
Linda Lin ◽  
Paul A. Kohl ◽  
J.B. Lee ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Three Dimensional ◽  
Interlayer Dielectrics ◽  
Polymer Dielectrics ◽  
Degree Of Orientation ◽  
High Degree ◽  
Interconnection Structure

ABSTRACTIn MCM-D applications, interlayer dielectrics separate and insulate metal conductors to form a three-dimensional interconnection structure. Due to the three-dimensional nature of these structures, the thermal, electrical and mechanical properties of the dielectricmaterials must be known for all orientations in order to correctly design and simulate devices. The most commonly used polymer in microelectronics, polyimide, exists in formulations which have been shown to have a high degree of orientation and exhibit anisotropicproperties.

scholarly journals Proliferative activity of the epithelium in squamous epithelial lesions of the cervix

2021 ◽  
Vol 50 (1) ◽  
pp. 34-36
Author(s):  
I. B. Manukhin ◽  
G. .N. Minkina
Keyword(s):  
Proliferative Activity ◽  
Cell Nuclei ◽  
Squamous Intraepithelial Lesion ◽  
Low Degree ◽  
Stratified Squamous Epithelium ◽  
Intraepithelial Lesion ◽  
Epithelial Lesions ◽  
High Degree ◽  
Proliferating Cell

As a criterion for precancerous changes in the stratified squamous epithelium of the cervix, its proliferative activity, studied using monoclonal antibodies PC-10 to the antigen of proliferating cell nuclei (PCNA), is considered. The results of the studies showed that patients with a low degree of squamous intraepithelial lesion are characterized by weak proliferative activity, and for patients with a high degree of lesion it is moderate and pronounced. An increase in proliferative activity is a prognostic factor that determines long-term persistence and the likely progression of the lesion.

STUDY OF CHARACTERISTICS OF MECHANICAL PROPERTIES OF GAS-DISTRIBUTING STATION PIPES METAL AFTER LONG-TERM OPERATION

2015 ◽  
pp. 86-91
Author(s):  
I. Yu. Bykov ◽  
I. N. Birillo ◽  
P. A. Kuzbozhev
Keyword(s):  
Mechanical Properties ◽  
High Pressure ◽  
Internal Pressure ◽  
Dynamic Loading ◽  
Static Loading ◽  
High Speed ◽  
Term Operation ◽  
Loading Effects ◽  
Static And Dynamic Loading

During operation the technological pipelines of gas-distributing station are affected by mechanical static loading resulted from internal pressure of gas in the high pressure pipelines and a dynamic loading from a high-speed stream of gas in low pressure pipelines. A comparison is made of characteristics of mechanical properties of gas-distributing station pipes metal after a long-term operation for the conditions of static and dynamic loading effects.

scholarly journals Analysis of the Behavior of Carbon Nanotubes on Cementitious Composites

2013 ◽  
Vol 2013 ◽  
pp. 1-17 ◽  
Author(s):  
Jorge Fernandes de Morais ◽  
Assed Naked Haddad ◽  
Laia Haurie
Keyword(s):  
Mechanical Properties ◽  
Carbon Nanotubes ◽  
Construction Industry ◽  
Cementitious Materials ◽  
Cementitious Composites ◽  
Science And Engineering ◽  
Nondestructive Tests ◽  
Deformation Properties ◽  
New Material ◽  
Strength And Durability

Nanotechnology has brought significant innovations in science and engineering. Carbon nanotube has been considered a new and outstanding material in nanoscience field with great potential application in the construction industry. The main objective of this study is to analyze the behavior of cementitious materials produced with the insertion of carbon nanotubes of multiple walls in different concentrations and compare their physic-mechanical properties with plain mortar. This research covers the examination of nanoscale cement products and the use of carbon nanotubes to increase the strength and durability of cementitious composites. Three different ratios of carbon nanotubes have been searched: 0.20, 0.40, and 0.60%. To evaluate the mechanical properties of the samples, destructive and nondestructive tests were carried out to obtain compressive strength, tensile strength by diametrical compression, and dynamic modulus of elasticity as well as to determine their deformation properties. Methods of instrumentation such as scanning electron microscopy and porosity were also used in the analysis of microstructure of the materials. The study presents graphs, tables, and figures describing the behavior of CNT added to mortars samples, allowing a better understanding of the use of this new material in the construction industry.

Deep Submergence Spherical Shell Window Assembly With Glass or Transparent Ceramic Windows for Abyssal Depth Service

1975 ◽  
Vol 97 (3) ◽  
pp. 1020-1034 ◽  
Author(s):  
J. D. Stachiw
Keyword(s):  
Spherical Shell ◽  
Ceramic Materials ◽  
Transparent Ceramic ◽  
Test Results ◽  
Assembly Design ◽  
Underwater Shock ◽  
Materials Used ◽  
Dynamic Loading Conditions ◽  
Static And Dynamic Loading

A total of 20 spherical shell windows with R0 = 4 in., Ri = 3 in., and 150 deg included spherical angle have been pressure tested under static and dynamic loading conditions. The tests included not only long term cyclic tests at 4500, 9000, 13,500, and 20,000 psi but also underwater shock tests at 450 psi static pressure. Two different gasket and four different transparent window materials were tested in the same metallic window flange with plane bearing surface. The transparent materials used in windows were glass ceramic CERVIT C-101, chemically surface compressed glass CERVIT SSC-201, borosilicate crown glass BK-7, and Plexiglas G acrylic plastic. The test results based on a total of over 10,000 hr of pressure testing indicate that the NUC 150 deg spherical shell window assembly design with t/Ri = 0.333 windows described in this paper can be routinely used in unmanned systems to any depth found in the ocean providing that the chemically surface compressed glass or transparent ceramic materials evaluated in this study are used in the assembly.

scholarly journals Mechanical Properties of Cement-Treated Soil Mixed with Cellulose Nanofibre

2021 ◽  
Vol 11 (14) ◽  
pp. 6425
Author(s):  
Hidenori Takahashi ◽  
Shinya Omori ◽  
Hideyuki Asada ◽  
Hirofumi Fukawa ◽  
Yusuke Gotoh ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Flexural Strength ◽  
Geotechnical Engineering ◽  
Strength Development ◽  
Soft Ground ◽  
Wood Cellulose ◽  
Treated Soil ◽  
Made In ◽  
Cement Treatment

Cellulose nanofibre (CNF), a material composed of ultrafine fibres of wood cellulose fibrillated to nano-order level, is expected to be widely used because of its excellent properties. However, in the field of geotechnical engineering, almost no progress has been made in the development of techniques for using CNFs. The authors have focused on the use of CNF as an additive in cement treatment for soft ground, where cement is added to solidify the ground, because CNF can reduce the problems associated with cement-treated soil. This paper presents the results of a study on the method of mixing CNF, the strength and its variation obtained by adding CNF, and the change in permeability. CNF had the effect of mixing the cement evenly and reducing the variation in the strength of the treated soil. The CNF mixture increased the strength at the initial age but reduced the strength development in the long term. The addition of CNF also increased the flexural strength, although it hardly changed the permeability.

Hate Crime and Place: The Spatial and Temporal Concentration of Bias-Motivated Crime in Washington, D.C.

2021 ◽  
pp. 088626052098781
Author(s):  
Marin R. Wenger ◽  
Brendan Lantz
Keyword(s):  
Hate Crime ◽  
Hate Crimes ◽  
Temporal Perspective ◽  
Spatial Stability ◽  
Units Of Analysis ◽  
Crime Types ◽  
High Degree ◽  
Block Groups ◽  
Street Segments

Prior research suggests that many crime types are spatially concentrated and stable over time. Hate crime, however, is a unique crime type that is etiologically distinct from others. As such, examination of hate crime from a spatial and temporal perspective offers an opportunity to understand hate crime and the spatial concentration of crime more generally. The current study examines the spatial stability of hate crimes reported to the police in Washington, D.C., from 2012 through 2018 using street segments, intersections, and block groups as units of analysis. Findings reveal that hate crime is spatially concentrated, with less than 4% of street segments and intersections experiencing hate crime over the study period. Results reveal a high degree of spatial stability, both year-to-year and over the long term even when restricting the analysis to units that experienced at least one hate crime.

scholarly journals Influence of the Share of Renewable Energy Sources on the Level of Energy Security in EECCA Countries

Energies ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 903 ◽  
Author(s):  
Ivan Trifonov ◽  
Dmitry Trukhan ◽  
Yury Koshlich ◽  
Valeriy Prasolov ◽  
Beata Ślusarczyk
Keyword(s):  
Renewable Energy ◽  
Energy Security ◽  
Structural Characteristics ◽  
Renewable Energy Sources ◽  
Energy Resource ◽  
Energy Sources ◽  
Structural Content ◽  
High Degree

In this study we aimed to determine the extent to which changes in the share of renewable energy sources, their structural complex, and the level of energy security in Eastern Europe, Caucasus and Central Asia (EECCA) countries in the medium- and long-term are interconnected. The study was performed through modeling and determination of the structural characteristics of energy security in the countries. The methodology of the approach to modeling was based on solving the problem of nonlinear optimization by selecting a certain scenario. For the study, the data of EECCA countries were used. The ability of EECCA countries to benefit from long-term indirect and induced advantages of the transformation period depends on the extent to which their domestic supply chains facilitate the deployment of energy transformation and induced economic activity. This study provides an opportunity to assess the degree of influence of renewable energy sources on the level of energy security of countries in the context of energy resource diversification. The high degree of influence of renewable energy sources on energy security in the EECCA countries has been proven in the implementation of the developed scenarios for its increase. Energy security is growing. At the same time, its level depends not only on an increase in the share of renewable sources but also on the structure of energy resources complex of countries, and the development of various renewable energy sources. Therefore, today the EECCA countries are forced not only to increase the share of renewable energy sources but also to attach strategic importance to the structural content of their energy complex.

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