scholarly journals STUDY OF THE PROPERTIES OF ELASTOMERS BASED ON BUTADIENE NITRILE, ETHYLENE-PROPYLENE RUBBERS AND CHLOROSULPHATED POLYETHYLENE

2020 ◽  
pp. 112-121
Author(s):  
I. A. Novakov ◽  
Minh Thuy Dang ◽  
M. A. Vaniev ◽  
D. A. Nilidin ◽  
S. G. Gubin ◽  
...  
Keyword(s):  
Heat Resistance ◽  
High Resistance ◽  
Frost Resistance ◽  
Field Tests ◽  
Climatic Zones ◽  
Climate Conditions ◽  
Ethylene Propylene ◽  
First Time ◽  
Fuel Resistance ◽  
Prospects Of Application

The properties of elastomers based on a combination of acrylonitrile-butadiene (NBR), ethylene-propylene (EPDM) rubbers and chlorosulfinated polyethylene (CSM) have been studied for the first time, which have been vulcanized by sulfur-free effective systems. The best balance in terms of frost resistance, heat resistance and fuel resistance is demonstrated by rubbers whose formulations are generally dominated by polar CSM and NBR with lower EPDM content (10-20 mas.h). The results of six-month field tests in tropical climate conditions demonstrate high resistance of elastomers to microorganisms. The obtained results stipulate the prospects of application of the created rubbers for operation in different climatic zones.

Features of radiothermoluminescence of polypropylene and ethylene propylenediene elastomer SKEPT-4044 compositions with nanoscale metal-containing fillers

2020 ◽  
pp. 66-73
Author(s):  
A.M. Magerramov ◽  
◽  
N.I. Kurbanova ◽  
M.N. Bayramov ◽  
N.A. Alimirzoyeva ◽  
...  
Keyword(s):  
Transition Temperature ◽  
Molecular Mobility ◽  
Fe3o4 Nanoparticles ◽  
Low Temperatures ◽  
Frost Resistance ◽  
Relaxation Processes ◽  
Ethylene Propylene ◽  
Temperature Range ◽  
Β Relaxation

Using radiothermoluminescence (RTL), the molecular mobility features in the temperature range of 77-300 K were studied for the polypropylene (PP)/ethylene propylene diene elastomer SKEPT-4044 with NiO, Cu2O and Fe3O4 nanoparticles (NPs) based on ABS-acrylonitrile butadiene or SCS-divinyl styrene matrices. It has been shown that the introduction of nanofillers in PP significantly affects the nature and temperature of γ- and β-relaxation processes, while the region of manifestation of the β-process noticeably shifts to the region of low temperatures. Composites with Cu2O NPs have a higher β-transition temperature Tβ than composites with other NPs. It was found that PP/SKEPT-4044 composites with Cu2O NPs with a dispersion of 11-15 nm and acrylonitrile butadiene thermoplastics have optimal frost resistance compared to other compositions.

Lichens of the Oasis Molodyozhnyi and adjacent areas (Enderby Land, Antarctic)

2013 ◽  
Vol 47 ◽  
pp. 167-178 ◽  
Author(s):  
M. P. Andreev
Keyword(s):  
Liquid Water ◽  
Climate Conditions ◽  
Water Ice ◽  
Buellia Frigida ◽  
Antarctic Continent ◽  
Harsh Climate ◽  
The Antarctic ◽  
First Time ◽  
Lichen Flora

Lichen flora and vegetation in the vicinity of the Russian base «Molodyozhnaya» (Enderby Land, Antarctica) were investigated in 2010–2011 in details for the first time. About 500 specimens were collected in 100 localities in all available ecotopes. The lichen flora is the richest in the region and numbers 39 species (21 genera, 11 families). The studied vegetation is very poor and sparse, but typical for coastal oases of the Antarctic continent. The poorness is caused by the extremely harsh climate conditions, insufficient availability of liquid water, ice-free land, and high insolation levels. The dominant and most common lichens are Rinodina olivaceobrunnea, Amandinea punctata, Candelariella flava, Physcia caesia, Caloplaca tominii, Lecanora expectans, Caloplaca ammiospila, Lecidea cancriformis, Pseudephebe minuscula, Lecidella siplei, Umbilicaria decussata, Buellia frigida, Lecanora fuscobrunnea, Usnea sphacelata, Lepraria and Buellia spp.

Innovations Based on PCC

2013 ◽  
Vol 687 ◽  
pp. 369-377 ◽  
Author(s):  
Andrea Dimmig-Osburg
Keyword(s):  
Mechanical Engineering ◽  
Field Tests ◽  
Innovative Development ◽  
Self Compacting Concrete ◽  
Cement Ratio ◽  
Water Cement Ratio ◽  
Innovation Potential ◽  
Acrylic Ester ◽  
Bridge Building ◽  
First Time

Abstract. In this paper, three examples for the application of PCC are presented, which exceed the well established use as restoration material and show the great innovation potential of these materials. The first example shows an innovative development of a polymer-modified self-compacting concrete (SPCC) for the restoration of vertical facing concrete surfaces. In the second example PCC was for the first time applied as construction concrete to a bridge building. The last instance describes the potential of the SPCC for special applications in mechanical engineering. A styrene acrylic ester dispersion and different sorts of cement were used. The polymer/cement-ratio varied from 0.05 to 0.10. The water/cement-ratio depended on the requirements of the different PCC. The essential laboratory and field tests as well as the results are described.

scholarly journals A short history of climate change

2020 ◽  
Vol 246 ◽  
pp. 00002
Author(s):  
Dirk Notz
Keyword(s):  
Climate Change ◽  
Energy Production ◽  
Short History ◽  
Unique Challenge ◽  
Climate Conditions ◽  
The Earth ◽  
Two Factors ◽  
History Of ◽  
Natural Climate ◽  
First Time

The flux of energy through the climate system determines the living conditions of our planet. In this contribution, I outline the main processes regulating this flux of energy, how these processes have changed throughout Earth history, and how today they are changing by human activities, in particular by activities related to energy production. The changes in the climate state of our planet, which have been ongoing ever since the formation of the Earth some 5 billion years ago, have shaped the world we live in today. Yet, today’s climate change is special in two overarching ways. First, it is the first time that a major climate change is globally affecting a civilisation that is perfectly adapted to thousands of years of stable climate conditions. Second, today’s climate change is occurring at a rate much faster than preceding natural climate changes. In combination, these two factors make today’s climate change a unique challenge to humankind, with direct consequences of future energy production as outlined in the other contributions to this volume.

scholarly journals Field Test Investigation of the Pile Jacking Performance for Prefabricated Square Rigid-Drainage Piles in Saturated Silt Sandy Soils

2019 ◽  
Vol 2019 ◽  
pp. 1-11 ◽  
Author(s):  
Xiangying Wang
Keyword(s):  
Pore Water ◽  
Field Test ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Field Tests ◽  
Excess Pore Water Pressure ◽  
New Type ◽  
Test Investigation ◽  
First Time ◽  
Excess Pore

The rigid-drainage pile, designed to accelerate the dissipation of excess pore water pressure around the pile, is a new type of pile that combines the bearing capacity of ordinary rigid piles and the draining capacity of gravel piles. Field tests of these new piles were performed for the first time at a construction site in the new campus of Jiangyin No. 1 High School. Numerous parameters were observed for the test piles in many trials, including the excess pore water pressures, horizontal soil pressures, and displacements. At the measuring position at 0.6 m from the pile center, the rigid-drainage pile dissipates 70% of the peak excess pore water pressure in 1000 s, whereas the ordinary pile requires nearly 4000 s to dissipate the identical amplitude. The field test results clearly demonstrate that the rigid-drainage pile can reduce the amplitude of the peak pressure caused by piling in the liquefiable layer, quickly dissipate the excess pore water pressure, reduce the loss of effective stress in the soil surrounding the pile, and maintain the foundation stability.

scholarly journals New WSR-88D Volume Coverage Pattern 12: Results of Field Tests

2005 ◽  
Vol 20 (3) ◽  
pp. 385-393 ◽  
Author(s):  
Rodger A. Brown ◽  
Vincent T. Wood ◽  
Randy M. Steadham ◽  
Robert R. Lee ◽  
Bradley A. Flickinger ◽  
...  
Keyword(s):  
Field Tests ◽  
Test Bed ◽  
Scanning Strategy ◽  
Severe Storms ◽  
National Network ◽  
Lower Elevation ◽  
Storm Cells ◽  
Scanning Strategies ◽  
First Time

Abstract For the first time since the installation of the national network of Weather Surveillance Radar-1988 Doppler (WSR-88D), a new scanning strategy—Volume Coverage Pattern 12 (VCP 12)—has been added to the suite of scanning strategies. VCP 12 is a faster version of VCP 11 and has denser vertical sampling at lower elevation angles. This note discusses results of field tests in Oklahoma and Mississippi during 2001–03 that led to the decision to implement VCP 12. Output from meteorological algorithms for a test-bed radar using an experimental VCP were compared with output for a nearby operational WSR-88D using VCP 11 or 21. These comparisons were made for severe storms that were at comparable distances from both radars. Findings indicate that denser vertical sampling at lower elevation angles leads to earlier and longer algorithm identifications of storm cells and mesocyclones, especially those more distant from a radar.

scholarly journals Impurity-controlled densification: a new model for stratified polar firn

2013 ◽  
Vol 59 (218) ◽  
pp. 1163-1169 ◽  
Author(s):  
Johannes Freitag ◽  
Sepp Kipfstuhl ◽  
Thomas Laepple ◽  
Frank Wilhelms
Keyword(s):  
Ice Cores ◽  
Ion Concentration ◽  
Impurity Effect ◽  
Air Entrapment ◽  
Density Profiles ◽  
Climate Conditions ◽  
Order Of Magnitude ◽  
Effect Of Impurities ◽  
The One ◽  
First Time

AbstractA new densification model, which simulates the effect of impurities on the densification of polar firn, is presented. The classical densification models of Herron and Langway (1980) and Pimienta and Barnola (Barnola and others, 1991) are modified by assuming that the activation energy for deformation is reduced by the impurities. Motivated by recent observations, the impurity effect is formulated on an empirical basis using the seasonally varying Ca2+ ion concentration. Excellent agreement between simulated and measured high-resolution density profiles confirms the new approach. The same parameterization applies for Greenland and Antarctica despite the one order of magnitude difference in impurity concentration. The new models allow us, for the first time, to simulate the density layering in firn down to the firn–ice transition. Our results emphasize the importance of impurities and density layering for the air entrapment and for dating gas records of deep ice cores, in particular for glacial climate conditions where the impurity concentrations are 10–100-fold higher than in modern firn.

High-performance heat resistant insulation materials for coils

1995 ◽  
Vol 7 (3) ◽  
pp. 325-336 ◽  
Author(s):  
Tohru Koyama ◽  
Katuo Sugawara ◽  
Chikasi Kanno ◽  
Syouichi Maruyama ◽  
Yoshikiyo Kashiwamura
Keyword(s):  
Heat Resistance ◽  
High Performance ◽  
Heterocyclic Ring ◽  
Cross Linking ◽  
Epoxide Resin ◽  
Traction Motor ◽  
Thermal Index ◽  
Low Viscosity ◽  
First Time ◽  
Good Workability

A new impregnating epoxide resin has been developed by optimizing cross-linking densities. The resin satisfies the thermal index of 210C: this is the first time an epoxide system without a heterocyclic ring has done so. Thermal class 220C insulating systems of traction motor coils are developed by interaction of the impregnating epoxide resin and epoxide binding resin in a new insulating tape. The newly developed epoxide impregnating resin has low viscosity and very good workability. Therefore, electrically insulated coils of various classes of heat resistance, such as class C (> 180C), class H (180 C) and class F (155C), can be prepared by using only a single kind of impregnating resin, by selecting the insulating tape and hardening conditions. It is unnecessary to keep various kinds of impregnating resin corresponding to the different beat resistant grades and it is possible to decrease drastically the amount of waste generated by using several different impregnating resins.

Preparation and Investigation on Properties of Shape Memory Epoxy Modified by Hyperbranched Polyester

2011 ◽  
Vol 335-336 ◽  
pp. 851-855 ◽  
Author(s):  
Chun Miao Han ◽  
Yu Yan Liu ◽  
Hui Feng Tan
Keyword(s):  
Heat Resistance ◽  
Shape Memory ◽  
Hyperbranched Polyester ◽  
Shape Memory Property ◽  
Elongation At Break ◽  
Memory Property ◽  
Negative Effect ◽  
Shape Retention ◽  
First Time ◽  
Hyperbranched Structure

A series of hyperbranched polyester (HBPE) modified shape memory epoxies (SMEPs) were prepared for the first time. The materials’ toughness, mechanical properties and heat resistance were investigated by impact test, tensile test and DSC analysis. Besides, the possible effect of hyperbranched structure on SMEP’s shape memory property was studied by fold-deploy shape memory test. The results showed 5wt. % HBPE modified SMEP had the optimum properties. Its impact strength, tensile strength and elongation at break were increased by 51.8, 11.4 and 25.4%, respectively, without negative effect on SMEP’s heat resistance and shape memory property. All the samples had high shape retention ratio and 100% shape recovery ratio.

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