The Influence of Size and Hardness of Sand Particles and Their Proportions on the Friction Characteristics of Cement Mortars: A Laboratory Study

1994 ◽  
Vol 16 (2) ◽  
pp. 140 ◽  
Author(s):  
RD Hooton ◽  
S Kolias
Keyword(s):  
Laboratory Study ◽  
Friction Characteristics ◽  
Cement Mortars ◽  
Sand Particles

A laboratory study of the electrostatic charge of individual sand particles lofted in an electric field

2021 ◽  
Vol 50 ◽  
pp. 100675
Author(s):  
Li Xie ◽  
Yakui Liu ◽  
Cheng Zhou ◽  
Mark Wang ◽  
Daniel J. Lacks ◽  
...  
Keyword(s):  
Electric Field ◽  
Laboratory Study ◽  
Electrostatic Charge ◽  
Sand Particles

Hydraulic performance of sewer pipes with deposited sediments

2008 ◽  
Vol 57 (11) ◽  
pp. 1743-1748 ◽  
Author(s):  
Robert Banasiak
Keyword(s):  
Discharge Capacity ◽  
Laboratory Study ◽  
Hydraulic Performance ◽  
Experimental Results ◽  
Cohesive Sediments ◽  
Sewer Pipes ◽  
Friction Characteristics ◽  
Study Results ◽  
Bed Forms ◽  
Sediment Deposit

This paper investigates in-sewer sediment deposit behaviour and its influence on the hydraulic performance of sewer pipes. This evaluation is based on experimental results regarding the mobility of non-cohesive and partly cohesive deposits in a partially full circular pipe. The focus of these tests is on the development of bed forms and friction characteristics. In particular, it is investigated to what extent the bed forms from the non-cohesive and (partly) cohesive sediments affect a sewer's discharge capacity. Based on the laboratory study results and on the existing criteria for sewer design, a generic assessment of a sewer's hydraulic performance is made. The relative discharge factor for a pipe with sediment deposit is analysed in terms of the thickness and roughness of the deposit.

STUDIES ON THE ACTION OF SULPHATES ON PORTLAND CEMENT: II. STEAM-CURING OF PORTLAND CEMENT MORTAR AND CONCRETE AS A REMEDY FOR SULPHATE (ALKALI) ACTION

1929 ◽  
Vol 1 (4) ◽  
pp. 359-384 ◽  
Author(s):  
T. Thorvaldson ◽  
V. A. Vigfusson ◽  
D. Wolochow
Keyword(s):  
Tensile Strength ◽  
Compressive Strength ◽  
Portland Cement ◽  
Laboratory Study ◽  
Cement Mortar ◽  
Steam Curing ◽  
Cement Mortars ◽  
Sodium Magnesium ◽  
The Stability

A study was made of the effect of steam-curing at various temperatures between 50° and 200 °C. on the resistance of Portland cement mortars to the action of solutions of the sulphates of sodium, magnesium and calcium. The methods used consisted in comparing the expansion of steam-cured and untreated mortar specimens during exposure to the solutions, and in determining the changes in the tensile strength of the more resistant mortars after long periods of exposure.A laboratory study of steam-curing as a remedy for the action of sulphates ("alkali") on Portland cement mortars, was made by determining the effect on the stability of the mortar as indicated by changes in volume and in tensile strength on exposure to sulphate solutions at 21 °C. The effect of steam-curing on the tensile and compressive strength of mortars and concrete was also studied.

Paper 10: Total Human Hip Joint Prostheses—A Laboratory Study of Friction and Wear

1966 ◽  
Vol 181 (10) ◽  
pp. 90-103 ◽  
Author(s):  
I. Duff-Barclay ◽  
D. T. Spillman
Keyword(s):  
Hip Joint ◽  
Laboratory Study ◽  
Friction And Wear ◽  
Special Equipment ◽  
Artificial Joints ◽  
Friction Characteristics ◽  
Wear And Friction ◽  
Bearing Materials ◽  
Joint Prostheses

The design of artificial joints is determined by anatomical surgical, and physical considerations. A review of previous work has shown the need for data on the lubrication, wear, and friction characteristics of suitable biologically acceptable bearing materials. To obtain this information special equipment has been designed which can simulate the motions and loadings that occur in the hip joint during walking. The results of the investigations are presented.

Laboratory and in-situ analysis of comet dust

1988 ◽  
Vol 46 ◽  
pp. 8-9
Author(s):  
D.E. Brownlee ◽  
A.L. Albee
Keyword(s):  
Electron Microscopy ◽  
Solar System ◽  
Laboratory Study ◽  
Isotopic Analysis ◽  
Building Blocks ◽  
Sem Analysis ◽  
Early Solar System ◽  
Cometary Material ◽  
Comet Dust

Comets are primitive, kilometer-sized bodies that formed in the outer regions of the solar system. Composed of ice and dust, comets are generally believed to be relic building blocks of the outer solar system that have been preserved at cryogenic temperatures since the formation of the Sun and planets. The analysis of cometary material is particularly important because the properties of cometary material provide direct information on the processes and environments that formed and influenced solid matter both in the early solar system and in the interstellar environments that preceded it.The first direct analyses of proven comet dust were made during the Soviet and European spacecraft encounters with Comet Halley in 1986. These missions carried time-of-flight mass spectrometers that measured mass spectra of individual micron and smaller particles. The Halley measurements were semi-quantitative but they showed that comet dust is a complex fine-grained mixture of silicates and organic material. A full understanding of comet dust will require detailed morphological, mineralogical, elemental and isotopic analysis at the finest possible scale. Electron microscopy and related microbeam techniques will play key roles in the analysis. The present and future of electron microscopy of comet samples involves laboratory study of micrometeorites collected in the stratosphere, in-situ SEM analysis of particles collected at a comet and laboratory study of samples collected from a comet and returned to the Earth for detailed study.

Chemical Classification and Particle Sizing of Foundry Sands

1985 ◽  
Vol 43 ◽  
pp. 388-389
Author(s):  
D.S. DeMiglio
Keyword(s):  
Image Analysis ◽  
Energy Dispersive Spectrometer ◽  
Image Analysis System ◽  
Representative Sampling ◽  
Foundry Sands ◽  
Large Atomic Number ◽  
Backscattered Electron ◽  
Sand Particles ◽  
Analysis System ◽  
Reclamation System

Much progress has been made in recent years towards the development of closed-loop foundry sand reclamation systems. However, virtually all work to date has determined the effectiveness of these systems to remove surface clay and metal oxide scales by a qualitative inspection of a representative sampling of sand particles. In this investigation, particles from a series of foundry sands were sized and chemically classified by a Lemont image analysis system (which was interfaced with an SEM and an X-ray energy dispersive spectrometer) in order to statistically document the effectiveness of a reclamation system developed by The Pangborn Company - a subsidiary of SOHIO.The following samples were submitted: unreclaimed sand; calcined sand; calcined & mechanically scrubbed sand and unused sand. Prior to analysis, each sample was sprinkled onto a carbon mount and coated with an evaporated film of carbon. A backscattered electron photomicrograph of a field of scale-covered particles is shown in Figure 1. Due to a large atomic number difference between sand particles and the carbon mount, the backscattered electron signal was used for image analysis since it had a uniform contrast over the shape of each particle.

When Apologies for Injustice Matter

2008 ◽  
Vol 13 (4) ◽  
pp. 239-247 ◽  
Author(s):  
David De Cremer ◽  
Barbara C. Schouten
Keyword(s):  
Laboratory Study ◽  
Interaction Effect ◽  
Interactive Effect ◽  
Cross Sectional ◽  
Fairness Perceptions ◽  
Organizational Survey ◽  
Experimental Laboratory

The present research examined the idea that the effectiveness of apologies on promoting fairness perceptions depends on how meaningful and sincere the apology is experienced. More precisely, it was predicted that apologies are more effective when they are communicated by an authority being respectful to others. A study using a cross-sectional organizational survey showed that an apology (relative to giving no apology) revealed higher fairness perceptions, but only so when the authority was respectful rather than disrespectful. In a subsequent experimental laboratory study the same interaction effect (as in Study 1) on fairness perceptions was found. In addition, a similar interaction effect also emerged on participants’ self-evaluations in terms of relational appreciation (i.e., feeling valued and likeable). Finally, these self-evaluations accounted (at least partly) for the interactive effect on fairness perceptions.

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