FLOW BEHAVIOR OF CLARIFIED ORANGE JUICE AT LOW TEMPERATURES

This paper presents a study of the rheological behavior of clarified and depectinated orange juices, with different soluble solid contents, at temperatures just above their freezing point. The rheological behavior of depectinated and clarified orange juice was determined for a wide range of soluble solid contents (10–65.8° Brix) and temperatures ( − 15 to 30C). The results indicated that the samples behave like a Newtonian fluid. The effect of temperature on the juice can be described with an Arrhenius-type equation. It was found that the activation energy for viscous flow was in the range of 9.4 to 59 kJ/mol, depending on the concentration. The effect of the soluble solid content can be described by an exponential-type equation. Finally, an equation in which dynamic viscosity depends on temperature and soluble solids content gives the following expression: η =  1  ×  10 ^{- 15} exp(0.12C  +  9021/T), where T in Kelvin, C in °Brix, and viscosity in mPa·s.

PRACTICAL APPLICATIONS

It is necessary to know the relationship between viscosity with temperature and concentration, since knowledge of these parameters is of vital importance in the manipulation, calculation and design of all those unit operations during the process, mainly those based on heat and quantum transfer.     

INFERENCE OF ATTITUDES FROM NONVERBAL COMMUNICATION IN TWO CHANNELS.

3 DEGREES OF ATTITUDE (I.E., POSITIVE, NEUTRAL, AND NEGATIVE) IN FACIAL EXPRESSION WERE EACH COMBINED WITH 3 DEGREES OF ATTITUDE COMMUNICATED VOCALLY. THE VOCAL COMMUNICATIONS OF ATTITUDE WERE SUPERIMPOSED ON A NEUTRAL WORD. IN PREPARING THE 2-COMPONENT COMMUNICATIONS, THE COMPONENTS WERE SELECTED SO THAT THE DEGREE OF POSITIVE ATTITUDE COMMUNICATED FACIALLY WAS EQUIVALENT TO THAT COMMUNICATED VOCALLY-I.E., THE INDEPENDENT EFFECTS OF THE 2 COMPONENTS WERE COMPARABLE. IT WAS FOUND THAT ATTITUDES INFERRED FROM COMBINED FACIAL-VOCAL COMMUNICATIONS ARE A LINEAR FUNCTION OF THE ATTITUDES COMMUNICATED IN EACH COMPONENT, WITH THE FACIAL COMPONENT RECEIVING APPROXIMATELY 3/2 THE WEIGHT RECEIVED BY THE VOCAL COMPONENT. IMPLICATIONS OF THE FINDINGS FOR MORE GENERAL ATTITUDE-COMMUNICATION PROBLEMS ARE DISCUSSED. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Crystal Chemistry of Hydrous Calcium Silicates: III, Morphology and Other Properties of Tobermorite and Related Phases

Three very similar hydrous calcium silicates that serve as binders for, or are closely related to the binding material of, autoclaved and moist-air-cured concrete and related products have been differentiated by electron microscopy, X-ray diffraction, differential thermal analysis, infrared absorption, degree of stability to the acetoacetic ester, and oxide composition. Tobermorite, 4–5CaO.5SiO₂.5H₂O, is the binder of properly autoclaved concrete and related products. It integrates uniformly into a dimension-ally stable solid of high strength. This phase is identified by X-ray diffraction lines at 11, 3.07, and 2.97 a.u. of strong intensity, by a basal spacing at 11 a.u., and by a flat platy crystal habit. The analogous hydrate of similar CaO/SiO₂ molar ratio (C/S) and designated the 0.8 to 1.33 C/S hydrate, generally shows a basal spacing at 14 a.u., occurs in crinkly foils, and exhibits a strong exothermic effect in differential thermal analysis at 835° C. This phase differs markedly from tobermorite, does not undergo any crystal-to-crystal binding, and shows some of the physical characteristics of clay. It is the low-lime intermediate in the formation of tobermorite. The binder of low-pressure-steam-cured concrete occurs in part in gel-like globules, sometimes in the shape of spheres. This phase, having a probable composition anywhere between 1.5 and 2.0 C/S, depending on the time of curing, is characterized by the gel-like morphological characteristic, a basal spacing of about 10 a.u., and variable but still characteristic differential thermal analysis effects. Apparently the same product is obtained by reacting lime and silicic acid, but it Occurs in the form of distinctly fibrous crystals.     

Relation Between Refractive Index and Elastic Moduli of a Borosilicate Glass After Heat-Treatment

Several specimens of a borosilicate glass were subjected to a series of different annealing schedules and the refractive indices and elastic moduli were measured and compared after each heat-treatment. The elastic moduli were determined by a dynamic resonance method at frequencies both within and slightly above the sonic range. The refractive indices were measured on the Grauer refractometer. A linear relation was found to exist between these two properties for specimens with different heat-treatments. A linear relation has already been established between refractive index and density by several investigators. This indicates that a single fictive temperature (τ) scale can be used to characterize the condition of a glass with respect to three properties: index of refraction, density, and elastic moduli.     

The Houston Growth Coalition In “Boom” and “Bust”

ABSTRACT: Although growth machine theory emphasizes the coalition's tactics and organization, it neglects adjustment to changing economic conditions. This article explores the changes in the strategy and organization of Houston's growth coalition during the peak growth of the 1970s and the decline of the 1980s. During the boom, the coalition focused not on additional growth but on easing the city's infrastructure problems. The coalition underwent several major changes during decline as it struggled to compete aggressively with other cities for various enterprises and to devise strategies for diversifying the economy. A growth coalition has the opportunity to establish the economic basis for future growth when the city's dominant industries reach maturity and decline.     

CHEMICAL COMPOSITION OF TOMATOES AS AFFECTED BY MATURITY AND FERTIGATION PRACTICES

The objective of this study was to determine the effect of various fertigation practices and maturity stages on tomato fruit composition. Soluble solids, reducing sugar content, and sugar/acid ratio of tomatoes increased with maturity. Fertigation treatments had less of an effect on the chemical composition of the fruit than the stage of maturity. Mineral (P, K, Ca, Mg) levels of tomato fruits in fertigated treatments were higher than in the control plot treatments receiving no supplemental water during the production season. Ascorbic acid content in whole mature-red fresh tomatoes was 13.24% and 25.71% higher than that in mature-pink and mature-light pink tomatoes, respectively. The locule section contained more ascorbic acid than other parts of the fruit at maturity. Intensive mineral fertigation and harvesting at the ripe stage contributes toward higher nutritional quality in fresh tomatoes.     

FLOW PROPERTIES OF ORANGE DIETARY FIBER SUSPENSIONS

The flow behavior of 7–20% orange dietary fiber (DF) suspensions at 15–65C was most adequately described by the simple power law model. The effect of the temperature on the apparent coefficient of viscosity (η_app) followed an Arrhenius-type relationship. The flow activation energy (E_a) was in the range 3.0–14. 7kJ/mol, depending on the concentration. The η_app increased exponentially with concentration within the temperature range studied. The combined effect of temperature and concentration on the η_app could be represented by an exponential equation. In all the cases, the effect of concentration on η_app was more pronounced than that of the temperature.     

Crack Initiation and Arrest in a SiC Whisker/A12O3 Matrix Composite

The fracture initiation and arrest stress intensity factors were determined for a SiC-whisker-reinforced AI₂O₃ matrix composite. A chevron-notched, three-point-bend specimen was used to genera e the load/displacement curve, which exhibited repeated crack initiation, followed by crack arrest behavior. Corresponding stress intensity factors were determined for both situations using the compliance technique. Calculated crack arrest positions were in agreement with fractographic observations. Both the crack arrest and the crack initiation stress intensity factors exhibited a rising R -curve with increasing crack length, suggesting the presence of wake toughening effects on the crack growth resistance.     

Statistical Study of Thermal Fracture of Ceramic Materials in the Water Quench Test

The Weibull statistical theory of fracture was applied to thermal shock of ceramics in the water quench test. Transient thermal stresses and probability of failure were calculated for a cylindrical specimen cooled by convection. The convective heat transfer coefficient was calibrated using the time to failure which was measured with an acoustic emission technique. Theoretical failure probability distributions as a function of time and quench temperature compare favorably with experimental results for three high-alumina ceramics and a glass.