A Rough Shear-Thinning Correction for EHD Film Thickness

A film thickness correction for shear-thinning in elastohydrodynamic contacts has been available that requires parameters obtained from flow curves generated for the specific liquid. For instances for which reduced accuracy is acceptable, a new rough film thickness correction has been formulated for pure rolling and a moderate amount of sliding based on Van Krevelen's graphical technique of estimating shear-thinning from the molecular weight. It has been shown to be useful for high-molecular-weight base oils, when lubricant specific shear-thinning data is absent, although it should most often overestimate the film thinning.     

ON SOME EXPLICIT APPROXIMATE SOLUTIONS OF THE MAXWELL-STEFAN EQUATIONS FOR THE MULTICOMPONENT FILM MODEL

An explicit approximate solution of the Maxwell-Stefan equations, which describe mass transfer in multi-componcnt gas mixtures, for a film model is developed as a generalisation of a method by Burghardt and Krupiczka for diffusion through a mixture of stagnant gases. The consistent approach to explicit approximations described here also leads to the earlier general method of Krishna. Numerical examples demonstrate the superiority of the new approximation in problems involving mass transfer at high rates.     

Simulation of the Vacuum Infusion Process using Idealized Components: Effects of Pore Size and Suspension Concentration

Vacuum infusion of porous food matrices (i.e., extruded starch crackers) with calorically dense suspensions of food powders in fat was investigated in an ideal system. Experiments involved infusion of model matrices with lipid suspensions consisting of milled, size-characterized sucrose in corn oil. The influences of pore size/particle size ratio and suspension concentration on the penetration of liquid and particles were determined. A mathematical model that allows prediction of future behavior was fitted to the test results. The model indicates that dry-weight particle penetration is strongly correlated with pore size and independent of initial particle concentration. Infusion of liquid plus particles was increased by raising porosity and lowering particle concentration.     

MEASUREMENT OF FLUID FOOD VISCOSITY USING MICROFABRICATED RADIO FREQUENCY COILS

We report on the use and applicability of microfabricated radio frequency (r.f.) coils for viscosity measurements of fluid foods. The viscosity of fluid milk and milklike products was measured using nuclear magnetic resonance imaging based on microfabricated r.f. coils coupled to in‐line tubing with an inner diameter of 1.4 × 10^‐3 m. The fluid's apparent viscosity ranged from 0.002 to 0.08 Pa·s. The magnetic resonance‐based measurements were limited in shear rate range because of the small size of the coil. Magnetic resonance‐based measurements from 2 to 15 s^‐1 were obtained and were equivalent to off‐line rotational rheometry.     

RELATION of BACTERIAL DESTRUCTION to CHEMICAL MARKER FORMATION DURING PROCESSING BY THERMAL PULSES1

This paper presents a formulation in dimensionless terms of the equations pertaining to first-order processes that follow Arrhenius kinetics, and applies them to problems in food thermoprocessing. the need for it arose from attempts to understand the relation between destruction of pathogenic microorganisms and formation of chemical markers in the food. During processing food is subjected to a thermal pulse that affects the markers and microorganisms. the dimensionless formulation makes it convenient to obtain equations expressing the relation between the decadic reduction in microbial population and the rise in marker concentration for temperature-time profiles of forms hitherto not conveniently calculable. Measurements of chemical markers can be used with these formulas to predict destruction of microorganisms. Examples are given of calculations demonstrating the feasibility of this approach when a single marker is monitored.     

ON POWER EQUATIONS RELATING STRESS TO SHEAR RATE IN RHEOLOGY

A brief outline is given of the use history of power equations in rheology and dimensional difficulties are discussed. No complete explanation is yet available for the very wide application of these equations, but a few special cases are cited. Possible applications to texture studies are considered.     

SELF-RESPECT AND CIVIC CULTURE: TOWARDS INDICATORS

In this essay the concept of self-respect is defined as “deference among equals.” In exploring the application of the concept in modern cities, it is considered in the light of differentiation and inequalities, as well as the process of maintaining social order. From this ensues an examination of the situations in which respect is tendered or denied, by what are predictably public actions; from another point of view, they are Everyman's engagements with institutional structures and organizational rules. From these are developed possible indicators of (1) the degree to which self-respect exists for citizens and agents in terms of a common moral order and (2) the degree to which the social and physical environment are conducive to self-respect. Thus a rudimentary theory of self-respect, derived from the social psychology of Cooley and Meade, may be applied to compare American cities. Which cities have created a civic culture conducive to citizen self-respect?     

Developments in the measurement of reinforcement strain distributions in reinforced concrete members

A technique is described for measuring in detail the longitudinal strain distribution along the reinforcement of reinforced concrete members by means of strain gauges installed in a central duct within the reinforcement. Results of a preliminary test are given.