Composition and Refinement of Specifications of Parameterized Data Types

In [5] we introduced a framework for specification of parameterized data types utilizing a generalization of the traditional semantics based on the pushout construction. In the present paper, we address the issue of program development using this framework with particular emphasis on the notion of refinement. Unlike for the loose specifications, refinement does not amount merely to a narrowing of the model class, but primarily to introduction of additional structure into the specified program. We give examples based on the analogues of the classical vertical and horizontal composition of such specifications.     

Extruded wheat flour: Correlation between processing and product quality parameters

The influence of independent processing parameters on the product properties of extruded mixtures of wheat flour and water has been investigated. Physical, chemical, and sensory measurements are reported and correlated with underlying processing parameters. Such correlation could be used to automate and control the extrusion process.     

Reproductive status in female perch (Perca fluviatilis) outside a sewage treatment plant processing leachate from a refuse dump

Reproductive failure and endocrine disruption in female perch (Perca fluviatilis) and female brook trout (Salvelinus fontinalis), naturally exposed to toxic leachate from a municipal refuse dump, has raised concerns about the reproductive status in female fish outside the sewage treatment plant (STP), which now treats the same leachate. Female perch from the receiving water, Lake Siljan, were therefore sampled in a gradient from the STP in Fornby and Osterviken and compared with reference females from Isunda or Solleron. A high resolution gas chromatography/high resolution mass spectrometry (HRGC/HRMS) technique enabled the analysis of circulating steroids in blood plasma: the sex steroids progesterone (P), 17alpha-hydroxyprogesterone (17alpha-OHP), androstenedione (A), testosterone (T), estrone (E1), and 17beta-oestradiol (E2), the maturation-inducing hormone (MIH) 17alpha,20beta-dihydroxy-4-pregnen-3-one (17alpha,20beta-P), and the glucocorticoids 11-deoxycortisol (11-DC) and cortisol (C). Body and organ measurements, ratio of sexually mature (SM) females, and frequencies of body lesions, were also recorded. The percentages of SM females found in Fornby on Oct 23 (83.8%) and in Osterviken on May 14 (54.0%) were lower compared with Isunda (100%). The lack of differences in gonadosomatic index (GSI) and liver-somatic index (LSI) indicated a normal vitellogenesis in SM females from Fornby and Osterviken. No differences in circulating levels of steroids were observed between the sites, except at the time of spawning, when elevated P and 17alpha-OHP levels in females from Osterviken indicated a steroidogenic shift from the synthesis of sex steroids towards the production of the MIH 17alpha,20beta-P. The significant peak-levels of both 17alpha,20beta-P and 11-DC in female perch from Osterviken at the same time suggest that both are involved in controlling final oocyte maturation in perch. The elevated levels of androgens (A and T) in females caught on the same occasion in Fornby implied that these females were at an earlier stage of oocyte maturation, prior to the steroidogenic shift towards MIH-production. This study confirms the results of an earlier study revealing low numbers of SM female perch outside the STP in Fornby. The lack of associated effects on organ indexes and circulating levels of steroids does not indicate exposure to endocrine disrupting substances (EDSs) from the treated sewage. The consistently high numbers of SM females in the northern part of Siljan suggest, however, that natural factors are not responsible for the reproductive failures in the southern part of the lake.     

Material removal mechanism of Ni(200) when eroded by a slurry at 30° incidence

Ni(200) samples were eroded under steady state conditions by a slurry consisting of 30 wt.% 88–150 μm glass beads in 1 M NaClO₄ at 30° incidence angle and 30 m s^?1 velocity. Detailed optical and scanning electron microscopy examination was performed on the eroded surfaces and metallographic sections. A wavy surface topography formed by plastic deformation was observed. At the downstream sides of the wavecrests thin tongues are formed when the plastically deformed surface layer is gradually pushed over the crest of the waves. Material is removed when the tongues or fractions of them are torn off. Hence the material removal mechanism is a process of plastic flow and tearing of tongues.