INTRODUCING META-LEVELS TO QUALITATIVE REASONING

Current approaches to qualitative reasoning are largely based on a fixed framework for modeling the physical world and concentrate on the reasoning methods that support qualitative reasoning. This paper argues that we need several levels of abstraction and different viewpoints on how to model the physical world, in order to create systems that reason about the physical world in a flexible way. We present a framework that integrates the three basic approaches to qualitative reasoning and show how this framework can be used as a basis for a flexible qualitative reasoning system.     

Alkaline-Earth Tungstates: Equilibrium and Stability in the M-W-O Systems

Phase relations in the systems alkaline earth oxide-tungsten trioxide and their stability with metallic tungsten were investigated by the quenching technique using sealed capsules. In the system BeO-WO₂, no intermediate compounds were formed. Binary mixtures resulted in a eutectic at 1185°C and 37 mole % BeO. In the system MgO-WO₃, the 1:1 compound was stable and melted congruently at 1358°C. There are two crystalline modifications of this compound. The well-known wolframite-type form is stable below 1165°C. Two eutectics were found: 1120°C and 28.5 mole % MgO and 1318°C and 55.0 mole % MgO. In the systems CaO-WO₃, SrO-WO₃, and BaO-WO₃, two binary compounds are stable. The 1:1 compounds with the scheelite-type structure melt, respectively, at 1580°, 1535°, and 1475°C, and form eutectics with WO₃ at 1135°, 1073°, and 935°C, all with a eutectic composition near 75 mole % WO₃. The 3:1 compounds having the distorted (NH,)₃FeF₆-type structure melt at ∼2250°, 2225°, and 1795°C. The eutectics between these two compounds are at 1490°C and 56.5 mole % CaO, 1410°C and 57.0 mole % SrO, and 1320°C and 58.2 mole % BaO. Phase transformations to an ideal (NH₄)₃FeF₆-type structure in Sr₃WO₆ and Ba₃WO₆, were observed at 1100° and 805° C, respectively, by application of both high-temperature X-ray diffraction and DTA. At 1700°C, metallic tungsten exists in equilibrium with liquid, the alkaline earth oxides, W₁₈O₄₉, the 3:1 ternary oxides, and with combinations thereof.     

THE IMPACTS OF PRODUCT ACCEPTABILITY, BRAND VALUE AND PRICE ON RESPONSES OF FOODSERVICE PROFESSIONALS TO BULK TURKEY

The objective of the research is to assess the contribution of product itself, brand image, and stated price, respectively, as determiners of purchase intent for foodservice managers and food brokers. The paper presents two sets of results. The first set shows that on a blind basis products differ moderately in perceived quality, but perceived quality may change with branding. The effect of branding is idiosyncratic, varying by product, usage behavior of the panelist, and panelist's job. The second set of results shows that price is far more important than product quality as a determiner of purchase intent, but the interplay of quality, price and purchase intent varies by the nature of the respondent.     

RATING AMERICAN CITIES-CREDIT RISK,URBAN DISTRESS AND THE QUALITY OF LIFE

Since communities have failed to generate their own indicators of social and economic well-being and the quality of community life, they have been forced to rely on externally generated indicators, often presented in form of rankings comparing one community with another. Three such rankings are explored in this paper (1) credit risk, (2) urban distress, and (3) quality of life. While each of the ratings serves a particular purpose and clientele, none was designed with the needs or interests of cities in mind. These rankings affect the community in numerous ways both directly and indirectly by driving up the cost of borrowing, altering local priorities and distorting agendas, and by shaping the images held by persons and businesses of particular cities and the desirability of locating in them. Unless and until local governments are willing to generate their own indicators they are at the mercy of these and should be aware of their strengths and weaknesses.     

Setting Agendas for Community Change: The Community Goal-Setting Strategy

ABSTRACT: Communities find it difficult to set their agendas and act, hamstrung by fragmentation, internal division and incrementalism Yet in rapidly changing environments, localities can ill-afford to let nature take its course. As a consequence a number of communities have turned to goal-setting. This paper examines community goal setting as a strategy of change. Three types of goals projects are identified the American Assembly Process, Anticipatory Democracy, and Strategic Planning. In considering their strengths and weaknesses, we ask(1) Who initiates the process for what purpose? (2) What problems are encountered? and (3) Is the public interest being served? Goal-setting, while not a replacement for government, can serve as a useful strategy to aid cities in transition.     

Phase Relations in Refractory Metal-Oxygen Systems

Phases and phase relations in the tungsten-oxygen, molybdenum-oxygen, tantalum-oxygen, and niobium-oxygen systems are reviewed.     

Equilibria in KAlF4-Containing Systems

Stability relations in the systems KF-AlF₃, KAlF₄-RbAlF₄, and KAlF₄-RbAlF₄-KBF₄ were established using DTA, direct observational analysis, and quenching techniques. Two KF-AlF₃ compounds, K₃AlF₆ and KAlF₄, are stable and, on cooling, cubic KAlF₄ inverts (between -23° and +50°C) to an orthorhombic modification. On heating, the cubic form is stable to the congruent melting temperature of 574°± 1°C. Melting points of K₃AlF₆, and AlF₃ are 985° and 990°C, respectively. The compounds KAlF₄ and RbAlF₄ form a complete solid solution with a relatively narrow solidus-liquidus interval. As little as 5 mole % RbAlF₄ in the KAlF₄ lattice greatly affects the low-temperature inversion, causing it to occur below the temperature of liquid nitrogen (−196°C).     

Modeling Low Temperature Blanched Carrot Firmness Based on Heat Induced Processes and Enzyme Activity

A kinetic texture model was developed describing the low temperature blanching firming effect. The rupture stress of carrots during blanching at 55°, 65° and 75°C and subsequent cooking at 95° and 100°C was measured. Firming effects were highest at 55° and 65°C although shorter blanching times were needed at 65°C. Model parameters were estimated by non-linear regression analysis on these measurements. The model summarized the biochemical mechanisms occurring in the cell wall during processing. The model was suitable for process design purposes as well as for gaining a better understanding of the firming process.     

Effects of In Vitro Proteolysis on the Allergenicity of Major Whey Proteins

The effects of in vitro proteolysis on the allergenicity of major whey proteins (α-lactalbumin and β-lactoglobulin) by simulating the human gastrointestinal conditions were evaluated. The proteolysis of demineralized whey with pepsin (pH 2.0 for 30 min) and/or various pancreatic enzymes (pH 7.5 for 60 and 240 min) was performed by the pH-stat technique at 37°C. The enzyme inactivation was performed by heating at 80°C for 20 min. Allergenicity of the hydrolyzates was evaluated by RAST inhibition using sera obtained from children allergic to whey proteins. Selective proteolysis of whey by pepsin and α-chymotrypsin was the most efficient combination of enzymes to reduce the allergenicity of both α-lactalbumin and β-lactoglobulin. The above hydrolyzate could be used to develop an ingredient for infant milk formula with a lower allergenicity.     

Degradation of Aspartame in Yogurt Related to Microbial Growth

Three commercial yogurt cultures and strains of Lactobacillus bulgaricus and Streptococcus thermophilus isolated therefrom were evaluated for their effect on aspartame degradation during and after fermentation. The rate of aspartame loss was related to growth of the organisms. Differences in losses due to strain type did not appear signficiant. Aspartame degradation rates were correlated to metabolic rate of the culture. As the rate decreased, loss of aspartame decreased. As a result, less than 10% aspartame was degraded during 6 wk refrigerated storage. Results indicate aspartame should remain stable in yogurt, provided it is added after fermentation.