Practice for Determination of Weight and Shape Changes of Plastics Under Accelerated Service Conditions

1993 ◽  
Author(s):  
Keyword(s):  
Service Conditions ◽  
Shape Changes

Pressure-Induced Metabolic Activation of Platelets Demonstrated In Vitro by Determination of Malondialdehyde Formation

1984 ◽  
Vol 52 (01) ◽  
pp. 004-006 ◽  
Author(s):  
Alessandro Torsellini ◽  
Luca Doni ◽  
Wulf Palinski ◽  
Giovanni Guidi ◽  
Valeriano Lombardi
Keyword(s):  
Arachidonic Acid ◽  
Atmospheric Pressure ◽  
Platelet Rich Plasma ◽  
Metabolic Activation ◽  
Platelet Factor ◽  
Malondialdehyde Formation ◽  
Shape Changes

SummaryPlatelet rich plasma (PRP) exposed in vitro to 200 mm Hg above atmospheric pressure showed a significant increase in malondialdehyde (MDA) formation compared to PRP at atmospheric pressure. This difference is also evident when platelets are incubated with arachidonic acid.The increase of MDA demonstrates that the increased beta- thromboglobulin and platelet factor 4 in plasma and the shape changes of platelets after pressure stimulation in vitro that were described in a previous paper result from the release reaction.Pressure-induced effects in vivo are discussed

Dynamic Mechanical Properties of Sugarcane

2013 ◽  
Vol 811 ◽  
pp. 314-318
Author(s):  
Jan Džugan ◽  
Martina Maresova ◽  
Pavel Podany
Keyword(s):  
Mechanical Properties ◽  
Dynamic Loading ◽  
Dynamic Mechanical Properties ◽  
Recent Time ◽  
Optimized Design ◽  
Material Optimization ◽  
New Material ◽  
Service Conditions ◽  
Increasing Demand

New design of a sugarcane shredder is being performed within a research project. This kind of equipment used to be traditionally designed on the basis experiences up to recent time. With increasing demand for the material economic utilization and reliable service, new material optimized design of shredders is required. In order to be able to perform qualified design and material optimization, service conditions has to be known. The paper is dealing with determination of sugarcane mechanical properties under dynamic loading, as the shredding process is performed at high velocities in the range of several meters per second. The mechanical properties of the sugarcane are going to be subsequently used for calculation of in operation loading on shredder components in the further steps.

scholarly journals THE LABORATORY INVESTIGATIONS OF HIGH-DENSITY POLYETHYLENE DRAINS FOR APPLICATION IN TAILINGS

2020 ◽  
Vol 14 (1) ◽  
Author(s):  
Mihailo Muravljov ◽  
Petar Anagnosti ◽  
Aleksandar R. Savić
Keyword(s):  
High Density Polyethylene ◽  
Tangential Direction ◽  
High Density ◽  
Test Results ◽  
Specific Behavior ◽  
Tailings Pond ◽  
Laboratory Investigations ◽  
Service Conditions ◽  
Under Construction

For the purposes of draining material deposited in the tailings pond under construction, there was aneed to examine the properties of the high-density polyethylene drain tubes and the consistingmaterials in order to assess their adequacy in the specific conditions. The conducted laboratoryinvestigations of the samples cut from the tubes included: determination of bulk density, tensilestrength in the tangential direction, as well as the compressive strength in a radial direction.Representative samples of the tubes themselves were tested in two different loading dispositions, inorder to record the load-deflection effects. The test results indicated the specific behavior of thetested material in service conditions.

On the Rate Controlling Mechanism Operative During Superplastic Flow

1971 ◽  
Vol 29 ◽  
pp. 110-111
Author(s):  
E. Gecklini ◽  
L. J. Anderson ◽  
C. R. Barrett
Keyword(s):  
Grain Boundary ◽  
Room Temperature ◽  
Grain Boundary Sliding ◽  
Superplastic Flow ◽  
Localized Deformation ◽  
Controlling Mechanism ◽  
Boundary Sliding ◽  
Shape Changes ◽  
Mechanism Operative

This investigation is concerned with a determination of the rate controlling mechanisms operative during superplastic flow. The experimental technique involves the deformation of Pb-Sn eutectic samples in a scanning electron microscope. Surface observations of grain shape changes and grain boundary shearing are used to assess the importance of the various deformation mechanisms. As described below, the experimental observations are consistent with a model of grain boundary sliding in association with localized deformation near grain boundaries to maintain coherency.Experiments are carried out using a specially designed tensile stage in an AMR 900 microscope. The gage section of the tensile sample is 3 mm long, 2 mm wide and 0.5 mm thick. The grain size range investigated is 2 - 5μ and deformation is carried out at room temperature. The tensile stage is designed such that the ends of the sample are translated in opposite directions.

Factors Affecting Bond Strength between the Elements of Tires

1960 ◽  
Vol 33 (2) ◽  
pp. 556-580
Author(s):  
G. N. Buĭko ◽  
N. M. Arenzon ◽  
A. I. Tumanova ◽  
N. P. Zinchenko ◽  
N. A. Pruzhanskaya ◽  
...  
Keyword(s):  
Bond Strength ◽  
Point Of View ◽  
Factors Affecting ◽  
Synthetic Rubber ◽  
Decisive Importance ◽  
Physico Chemical ◽  
Technical Proficiency ◽  
Service Conditions ◽  
Butadiene Styrene

Abstract 1. Ply separation of tires is one of the essential factors reducing their mileage, particularly under difficult service conditions. Enhancement of the dynamic bond strength between elements of the tires is a most important line of study for increasing the mileage of tires based on synthetic rubber. 2. An analysis of defects in tires failing as a result of separation shows that for a given level of technical proficiency in handling synthetic rubber the adhesion type of separation between pliedup compounds or between rubber and cord (of viscose filament) is predominant. This form of failure is particularly characteristic of tires with vulcanizates based on butadiene/styrene rubber in all the main parts. 3. In investigations concerning separation phenomena in tires, decisive importance attaches to methods of determination of bond strength under conditions of dynamic loading of pliedup vulcanizates and rubber cord systems. We still do not have methods which could be regarded as fully satisfying the requirements proposed. However a series of methods have been provided which make it possible to assess, with an accuracy suitable for practical purposes, the effect of this or that factor upon the bond strength and to show the advantages and inadequacies of pliedup systems from the point of view of the operation of tires under actual service conditions. 4. The experimental results obtained show that the dynamic bond strength in pliedup systems, as also the endurance of the tires in relation to separation resistance, is determined by a complex body of physico-chemical and technological factors, by the construction of the articles, and also by the pattern of loading under repeated deformations. The general theoretical ideas developed in articles by some investigators, that the highest bond strength is to be achieved where full adhesion of the raw pliedup stocks takes place, as shown by the disappearance of boundaries between them, and that in all cases the factors which enhance the flowability of the stock enhance also the bond strength between them, were not confirmed experimentally.

Galactic orbits of stars

1966 ◽  
Vol 25 ◽  
pp. 93-97
Author(s):  
Richard Woolley
Keyword(s):  
Globular Cluster ◽  
Potential Field ◽  
High Velocity ◽  
Velocity Vector ◽  
Variable Stars ◽  
The Sun ◽  
Proper Motions ◽  
Rr Lyrae ◽  
The Galaxy

It is now possible to determine proper motions of high-velocity objects in such a way as to obtain with some accuracy the velocity vector relevant to the Sun. If a potential field of the Galaxy is assumed, one can compute an actual orbit. A determination of the velocity of the globular clusterωCentauri has recently been completed at Greenwich, and it is found that the orbit is strongly retrograde in the Galaxy. Similar calculations may be made, though with less certainty, in the case of RR Lyrae variable stars.

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