Effective Stress Theory of Shrinkage Phenomena

1971 ◽  
Vol 8 (4) ◽  
pp. 503-513 ◽  
Author(s):  
A. Sridharan ◽  
G. Venkatappa Rao
Keyword(s):  
Surface Tension ◽  
Effective Stress ◽  
Void Ratio ◽  
Applied Pressure ◽  
Experimental Studies ◽  
Satisfactory Explanation ◽  
Stress Theory ◽  
Factors Affecting ◽  
Repulsive Forces

Shrinkage is one of the important soil phenomena in which an engineer is interested. The various factors affecting shrinkage phenomena are discussed. The investigation deals with theoretical and experimental studies of the physical mechanism involved in the process of shrinkage of a clay soil. A modified effective stress concept has been made use of for a satisfactory explanation of the phenomena. The relative importance of dielectric constant (in effecting the electrical attractive and repulsive forces) and the surface tension on the shrinkage of a clay has been brought out, using various organic solvents as pore fluids. Kaolinite has been used in the experimental investigation which includes conventional shrinkage limit tests, tests on samples consolidated to 1 ton/ft2 (1.093 kg/cm2) with different fabric as well as the same initial fabric, tests on samples consolidated to different pressures, and finally tests on samples with constant external applied pressure. The experimental results reveal that the modified effective stress concept proposed governs the shrinkage phenomena. Though surface tension is believed to be the cause of shrinkage, it has been shown that the void ratio at the shrinkage limit is governed by the contact stress at particle contact and (or) between particles, as defined by the modified effective stress concept. The role of fabric and externally applied load on shrinkage is discussed.

The methodology of experimental research of the feed components extrusion process in order to improve its energy performance

2020 ◽  
pp. 147-152
Author(s):  
E. M. Ratnikov ◽  
D. O. Milko
Keyword(s):  
Experimental Studies ◽  
Energy Performance ◽  
Extrusion Process ◽  
Mathematical Methods ◽  
Screw Extruder ◽  
Mathematical Planning ◽  
Factors Affecting ◽  
Extrusion Processing ◽  
Definition Of

Annotation Purpose. Development of a program and methods for conducting experimental studies of the extrusion process with the definition of parameters and modes of operation of the extruder to improve its energy performance. Methods. Methods of mathematical statistics, synthesis, analysis, description and modeling were used. Results. The application of mathematical methods, in particular mathematical planning, reduces the number of experiments several times, and allows to evaluate the role of influencing factors, obtain a mathematical model of the process and determine the optimal conditions for its parameters and modes, etc. Conclusions. The methodology for experimental studies of a screw extruder is presented with the necessary equipment and methodology for processing the obtained experimental data. A mathematical method of planning, which reduces the number of experiments several times, allows us to evaluate the role of factors affecting productivity and energy intensity is presented. Keywords: extruder, auger, nutrients, research methodology, extrusion, processing, feed.

scholarly journals THE ROLE OF SURFACE TENSION IN BREAKING WAVES

1972 ◽  
Vol 1 (13) ◽  
pp. 22 ◽  
Author(s):  
Robert L. Miller
Keyword(s):  
Surface Tension ◽  
Natural Waters ◽  
Experimental Studies ◽  
Breaking Waves ◽  
Engineering Model ◽  
Constant Depth ◽  
Model Studies ◽  
Limit Form ◽  
Satisfactory Theory

Breaking criteria in the vicinity of the crest, such as limit crest angle and limit form, and larger dimensions such as limit height (H/L) and breaker height (Hb/db)» are found experimentally to be significantly affected by change in surface tension. A number of wave types were examined, including periodic waves, solitary waves, and standing waves, over both constant depth and uniform slopes. Variations in natural waters in some cases were found to be of equivalent magnitude to those induced for the experiments. The conclusion is drawn that surface tension should be taken into account in development of a satisfactory theory of breakers. It is also an important factor in experimental studies, particularly engineering model studies involving breaking waves.

scholarly journals The surface-tension-driven evolution of a two-dimensional annular viscous tube

2007 ◽  
Vol 593 ◽  
pp. 181-208 ◽  
Author(s):  
I. M. GRIFFITHS ◽  
P. D. HOWELL
Keyword(s):  
Surface Tension ◽  
Numerical Solutions ◽  
Applied Pressure ◽  
Three Dimensional ◽  
Two Dimensional ◽  
Free Surfaces ◽  
Final Shape ◽  
Capillary Tubing ◽  
Well Posed

We consider the evolution of an annular two-dimensional region occupied by viscous fluid driven by surface tension and applied pressure at the free surfaces. We assume that the thickness of the domain is small compared with its circumference, so that it may be described as a thin viscous sheet whose ends are joined to form a closed loop. Analytical and numerical solutions of the resulting model are obtained and we show that it is well posed whether run forwards or backwards in time. This enables us to determine, in many cases explicitly, which initial shapes will evolve into a desired final shape. We also show how the application of an internal pressure may be used to control the evolution.This work is motivated by the production of non-axisymmetric capillary tubing via the Vello process. Molten glass is fed through a die and drawn off vertically, while the shape of the cross-section evolves under surface tension and any applied pressure as it flows downstream. Here the goal is to determine the die shape required to achieve a given desired final shape, typically square or rectangular. We conclude by discussing the role of our two-dimensional model in describing the three-dimensional tube-drawing process.

A statistical theory of liquid crystalline mixtures: phase separation

1976 ◽  
Vol 352 (1668) ◽  
pp. 41-56 ◽  
Keyword(s):  
Liquid Crystal ◽  
Phase Separation ◽  
Liquid Crystalline ◽  
Experimental Studies ◽  
Phase Region ◽  
Crystal Formation ◽  
Two Phase ◽  
First Order ◽  
Repulsive Forces

The molecular field theory of multicomponent liquid crystalline mixtures, developed by Humphries, James & Luckhurst, has been extended to investigate the possibility of phase separation in binary mixtures of rods and spheres. This extension indicates that the addition of a spherical solute to a liquid crystal depresses the transition from the isotropic to the nematic phase. The solute induced phase transition is first order, although the nematic and isotropic phases are found to be separated by a two-phase region consisting of both nematic and isotropic phases. These qualitative conclusions of the theory are in complete accord with experiment and there is also reasonable agreement with certain quantitative predictions. The same problem has been tackled using a lattice model with purely repulsive anisotropic interactions; this theory would appear to be marginally less successful than our own which is based on a weaker anisotropic potential. Consequently it is not possible to use experimental studies of phase separation in binary liquid crystal mixtures to demonstrate the rôle of repulsive forces in liquid crystal formation.

Online shopping cart abandonment: a consumer mindset perspective

2020 ◽  
Vol 37 (5) ◽  
pp. 487-499
Author(s):  
Daniel Rubin ◽  
Chrissy Martins ◽  
Veronika Ilyuk ◽  
Diogo Hildebrand
Keyword(s):  
Online Shopping ◽  
Experimental Studies ◽  
Underlying Mechanism ◽  
Content Type ◽  
Factors Affecting ◽  
Shopping Cart ◽  
Online Retailers ◽  
Implementing Strategies ◽  
Shopping Cart Abandonment

Purpose While the popularity of online shopping has increased in recent years, surprisingly little research has examined the factors affecting consumers’ behavior in this context. Furthermore, though a widespread problem for companies, the phenomenon of online shopping cart abandonment has garnered even less attention. The purpose of this study is to examine the role of consumers’ mindsets in online shopping cart abandonment. Design/methodology/approach Three experimental studies were conducted to examine the effect of consumer mindsets (i.e. abstract vs concrete) on purchase intentions. Findings Results indicate that consumers who have an abstract (as opposed to concrete) mindset when shopping online rate the products they include in their shopping carts to be more important, and consequently are more likely to purchase them, reducing shopping cart abandonment. Practical implications The findings suggest that online retailers can reduce shopping cart abandonment by implementing strategies that allow consumers to think abstractly. Originality/value This research contributes to the literature by identifying an important underlying mechanism affecting online shopping cart abandonment.

DIESEL ENGINE OPERATION IN USE OF FUEL WITH ADDITIVES

2018 ◽  
pp. 18-24
Author(s):  
Petar Kazakov ◽  
Atanas Iliev ◽  
Emil Marinov
Keyword(s):  
Diesel Engine ◽  
Fuel Consumption ◽  
Diesel Fuel ◽  
Internal Combustion Engines ◽  
Experimental Studies ◽  
Combustion Engines ◽  
Engine Operation ◽  
Factors Affecting ◽  
Operating Modes ◽  
Positive Effects

Over the decades, more attention has been paid to emissions from the means of transport and the use of different fuels and combustion fuels for the operation of internal combustion engines than on fuel consumption. This, in turn, enables research into products that are said to reduce fuel consumption. The report summarizes four studies of fuel-related innovation products. The studies covered by this report are conducted with diesel fuel and usually contain diesel fuel and three additives for it. Manufacturers of additives are based on already existing studies showing a 10-30% reduction in fuel consumption. Comparative experimental studies related to the use of commercially available diesel fuel with and without the use of additives have been performed in laboratory conditions. The studies were carried out on a stationary diesel engine СМД-17КН equipped with brake КИ1368В. Repeated results were recorded, but they did not confirm the significant positive effect of additives on specific fuel consumption. In some cases, the factors affecting errors in this type of research on the effectiveness of fuel additives for commercial purposes are considered. The reasons for the positive effects of such use of additives in certain engine operating modes are also clarified.

Researching the factors influencing the satisfaction of master students at VNU School of Interdisciplinary Studies

2019 ◽  
Vol 35 (3) ◽  
Author(s):  
Do Huy Thuong ◽  
Nguyen Thi Phuong Hong
Keyword(s):  
Service Industry ◽  
Interdisciplinary Studies ◽  
Number Of Solutions ◽  
Factors Affecting ◽  
Training Institutions ◽  
Market Needs ◽  
Market Strategies ◽  
Students Satisfaction ◽  
Training Service

Improving the quality in order to keep up with the trend in the world is the vital task of training institutions today. Training institutions need to grasp market needs and satisfy the requirements of customers - learners. Nadiri, H., Kandampully, J & Hussain, K. (2009) argue that the managers in education need to apply market strategies that are being used by manufacturing and business enterprises and need to be aware that the role of training institutions is a service industry which is responsible for satisfying learner needs (Elliott & Shin, 2002). Currently, there have been many researches on students’ satisfaction. However, each research has its own objectives and is conducted on different scales. This study is implemented to provide information about the factors affecting master students’ satisfaction with the training service at VNU School of Interdisciplinary Studies (VNU SIS). Through it, the research offers a number of solutions to improving the satisfaction level of the master students at VNU SIS in the coming time.

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