THE DEVELOPMENT OF CERAMIC WORK AT THE UNIVERSITY OF NORTH DAKOTA1

The development of the Ceramics Department of the University of North Dakota; correlation of research in chemical and experimental laboratories and cultural value of the work; inexhaustible supplies of the state being utilized.     

FOrmation and reactivity of oxides and basic salts. I. Basic magnesium chlorides and sulphates

Reactions of lime and magnesia with magnesium chloride and sulphate have been studied in relation to industrial processes, namely, extraction of magnesium from sea-water and production of Sorel-type cements. Variations in phase composition, surface area and crystallite and aggregate sizes of the products have been correlated with experimental conditions. The solid limes react rapidly with the more dilute magnesium salt solutions, and the precipitated magnesium hydroxides are much more finely-divided. Basic magnesium salts initially formed are decomposed subsequently to hydroxide as the pH becomes stabilised at higher values. Greater concentrations of magnesium chloride give more extensive basic salt formation and prevent all of the lime going quickly into solution. Similar products are given with solid magnesium hydroxide and magnesium chloride and sulphate solutions. The Sorel-type cements obtained from magnesium oxide and the more concentrated chloride solutions set appreciably, even before loss of surface through final ageing. They show two distinct phases: (a) irregular grains of 10–50 μm diameter, and (b) acicular or tabular crystals up to 20μm long, mainly in radiating growths. By contrast, the magnesium oxysulphate crystals are not so elongated and the cements set with considerable loss of surface area, giving interlocking structures in which 20–50 μm-diameter grains are often ‘fused’ together as larger 400–500 μm aggregates.     

Microstructural Evolution in Annealed and Crept Silicon Nitride

The microstructure of a commercial sintered silicon nitride has been examined in the as-sintered condition, after annealing to a stable microstructure in either air or argon, and after creep deformation. Both as-sintered material and material annealed to a stable microstructure were crept. Extensive analytical electron microscopy has been used to determine the composition of the intergranular material (amorphous and crystalline). The as-sintered material contains an amorphous intergranular phase which partially devitrifies upon exposure to high temperatures. The residual intergranular glass is homogeneous throughout the samples (even though different crystalline products form near the surface and in the center of samples annealed in air) and stable. Creep deformation does not affect the microstructural evolution. It is, however, responsible for internal strain and some cavitation in the material.     

The fight against Alzheimer's disease.

Describes gains made in the US in the fight against Alzheimer's disease (AD), noting increased funding for research into its etiology and possible cure, the growth and formation of support groups for caregivers of AD patients, and investigations into alternative means of care to institutionalization such as respite care. (3 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The effect of smoking and light activity on metabolism in men.

This experiment examined the metabolic effects of smoking during rest and light activity under naturalistic conditions. Thirty-nine male subjects first completed a submaximal graded exercise treadmill test to standardize activity level. Then 3 groups of subjects—smokers smoking (SS), smokers not smoking (SNS), and nonsmokers (NS)—were exposed to 3 stages of rest or 3 stages of light activity with order of rest or activity randomly determined over 2 different days. Energy expenditure was monitored continuously during these sessions. Significant increases in smokers' energy expenditure were observed during light activity when compared with smokers not smoking and nonsmokers. No differences were identified among groups at rest. These findings strengthen the conclusion that smoking or its components contribute to metabolic changes during typical levels of daily activity and suggest a mechanism for the frequently observed relationship between smoking status and body weight. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Conceptualizing Exposure to Community Violence: An Application of Confirmatory Factor Analysis.

The primary goal of the present study was to demonstrate how the technique of confirmatory factor analysis (CFA) could be applied to common measurement issues within the school psychology literature. Specifically, the CFA technique was used to test several alternative factor structures thought to underlie a commonly used measure of exposure to community violence. Data were collected from 242 elementary and middle-school, inner city, African American students. Results illustrate the potential benefits and limitations of applying CFA. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

An analysis of the shear strength of recycled aggregates

Increasing the use of recycled aggregates in civil engineering applications has the potential to reduce the current natural aggregate consumption requirements of the construction industry. Current levels of natural aggregate production are under threat due to tighter restrictions on planning issues related to quarrying. This paper presents a study on the shear strength of recycled aggregates with relevance to the use of such materials as backfill to structures. The tests were conducted on crushed concrete and demolition debris in a 300 mm×300 mm×179 mm shear box, and the results were compared with those of a limestone aggregate. The paper also includes an investigation into the possible application of an analysis of dilatancy (originally developed for use in soil mechanics) to aggregates and in particular to those aggregates of a soft-grain type such as recycled aggregates.

---

Résumé Augmenter l'utilisation des granulats recyclés dans des applications de génie civil pourrait réduire la demande actuelle par l'industrie de construction pour des granulats naturels. Le niveau existant de production des granulats naturels est menacé par des restrictions accrues sur l'exploitation des carrières. On présente ici une étude sur la résistance au cisaillement des granulats recyclés dans le cadre de l'utilisation des ces matériaux comme remblayage d'ouvrages. Les essais ont été effectués sur du béton concassé et des débris de démolition dans une éprouvette pour essai de cisaillement (300 mm×300 mm×179 mm). Les résultats ont été comparés avec ceux obtenus pour un granulat calcaire. On présente également une investigation sur la possibilité de l'appliquer une analyse de dilatance (élaborée à l'origine pour étudier la mécanique des sols) aux granulats, et en particulier, aux granulats à grains tendres tels que les granulats recyclés.

     

Odd man out: Reply to reviewers

This is the author's reply to three very different reviews of Mind As Machine: A history of Cognitive Science (Vols 1-2). Two of the reviews, written by Paul Thagard and Jerry Feldman, engage with the book seriously. The third, by Noam Chomsky, does not. It is a sadly unscholarly piece, guaranteed to mislead its readers about both the tone and the content of the book. It is also defamatory. The author provides appropriate responses to all three.