A complete axiomatic semantics of spawning

Summary In modern imperative languages there are two commonly occurring ways to activate concurrently running tasks,splitting (cobegin...coend) andspawning. The programming language Ada makes use of both forms of task activation. We present a formal system for verifying partial correctness specifications of Ada tasks activated by spawning. The system is based upon a view of tasks as histories of events. We show how the mindset of splitting may be applicable when developing a formal system for reasoning about spawning. The resultant proof system is compositional, and a robust extension of partial correctness proof systems for sequential constructs. A transition model is given for spawning, and the proof system is proven complete in the sense of Cook [10] relative to this model, under certain reasonable assumptions. The specific proof rules given apply to a subset of Ada without real-time and distributed termination. Our approach to task verification applies to other imperative languages besides Ada, and the essential parts of our methodology are applicable to other formal systems besides those based on partial correctness reasoning. Sigurd Meldal is professor of informatics at the University of Bergen. He is interested in techniques and tools based on formal methods for development of concurrent software. His current foci are the investigation of algebraic approaches to nondeterminism, and the participation in the design of a concurrent specification, prototyping and implementation language. The latter supplements formal proof with support for run time control of consistency between concurrent systems as specified and as implemented. Meldal received his cand. real. (1982) and dr. scient. (1986) degrees in informatics from the University of Oslo.This research was supported by a grant from the Norwegian Research Council for Science and the Humanities, by the Defense Advanced Research Projects Agency/Information Systems Technology Office under the office of Naval Research contract N00014-90-J1232, by the Air Force Office of Scientific Research under Grant AFOSR83-0255 and by a Fulbright Scholarship from the US Educational Foundation in Norway     

Optimisation of the electric arc furnace lancing strategy by physical and numerical simulation

Due to a partial lack of detailed knowledge of the relevant physical processes, the operational proceeding of oxygen and solid material injection in the electric arc furnace is often still based on experience. Therefore, the influence of important operational parameters on the fluid dynamics of the DC electric arc furnace have been investigated to find optimised lancing conditions. Therefore, physical model trials and additional numerical simulation were performed. Based on a defined standard operation condition, oxygen‐ and particle flowrate, lance inclination and distance of the nozzle from melt surface were varied. Furthermore, different geometrical nozzle arrangements and the influence of the electric arc were investigated. The resulting mixing of the melt, particle dispersion, surface fluctuations, and foaming behaviour were compared. Suggestions have been made for improved lancing strategy and lance design.     

Weldability Aspects of a Newly Developed Duplex Stainless Steel LDX 2101

Duplex grades have, due to balanced chemical compositions of both filler and base metals, a weldability that allows for successful welding using a majority of the technically relevant techniques of today. In order to fulfil the performance requirements several aspects must be considered. In the heat affected zone (HAZ) the austenite reformation must be reasonably high and in the weld metal the microstructure must be stable so that e.g. high productivity welding and multi‐pass welding are possible, without precipitation of detrimental phases in previous passes. This paper addresses the effect of alloying elements and thermal cycles on phase balance in the high temperature HAZ (HTHAZ) of the newly developed lean duplex grade LDX 2101 (EN 1.4162, UNS S32101). Bead‐on‐plate welds and simulated weld structures have been produced and investigated using metallography, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The results are analysed using the thermodynamic database Thermo‐Calc and a model for phase transformation based on a paraequilibrium assumption for ferrite‐austenite transformation. In the temperature region outside the paraequilibrium domain, growth controlled by diffusion of substitutional elements was considered. The analysis follows a model by Cahn regarding grain boundary nucleated growth and the Hillert‐Engberg model on kinetics of spherical and planar growth.     

Influence of diesel particulate filter additives on biodiesel quality

The influence of the diesel particulate filter additives (DPA) SATACEN and EOLYS on biodiesel fuel quality has been evaluated. Both additives significantly affected the oxidation stability of neat biodiesel. The influence on acid values and CFPP was found to be only small. Combination of diesel additives with biodiesel additives like oxidation stability and CFPP improvers led to similar results. Results indicated that DPA also lowered the efficiency of the oxidation stability improver Baynox. Furthermore, the CFPP additives Chimec and Infineum were also prone to have a small influence on biodiesel oxidation stability.     

Die Erzeugung mitteldichter Faserplatten-MDF

Ohne Zusammenfassung     

Lightweight floors — Vibration

Civil Engineer Sigurd Hveem at the Norwegian Building Research Institute, BI, describes the laboratory and field tests carried out on the dynamic response of different lightweight timber floors to establish new design guidelines. NBI are also looking at theoretical calculation methods in order to predict the results obtained by measuring dynamic properties.     

Review of Coping strategies therapy for bulimia nervosa.

Reviews the book, Coping strategies therapy for bulimia nervosa by David L. Tobin (see record 2000-07256-000). The book starts with a short introduction of the need for combination treatments and the obstacles therapists have to overcome in order to arrive at a cost-effective care for bulimic patients. The first part of the book provides a framework for coping strategies therapy (CST). The author reviews empirical and theoretical models of psychotherapy. This discussion is followed by an overview of CST, with short summaries of the different doses of therapy that are a central outcome of the author's work. The second part of the book is an elaboration of the details of the different doses of therapy: Dose 1 (problem engagement with a "remoralizing" aim; 1-2 sessions), Dose 2 (problem engagement with a "remediating" aim; 3-8 sessions), Dose 3 (emotion engagement with a rehabilitating aim; 9-20 sessions), and Dose 4 (problem and emotion disengagement with the aim of "rooting out the source of the disease"; 50-100+ sessions). Each dose is a separate treatment program designed for a specific bulimic patient group, and each has a specific aim and starts at a specific level of motivation for change. Basic aims for the author are to justify the broad range of activities on a theoretical and empirical basis, to organize those activities to help clinicians make rationally administered interventions, to provide a rationale for combining diverse interventions, and to build an informed basis that facilitates clinical care. These are far-reaching aims, and the reviewer thinks Tobin takes a large and interesting step toward a more integrative understanding and practical approach to the treatment of eating disorders. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Wet spun fibers from solutions of cellulose in an ionic liquid with suspended carbon nanoparticles

Wet spun fibers from solutions of dissolving pulp in 1‐ethyl‐3‐methylimidazolium acetate (EmimAc) with up to 50 wt % (based on cellulose) suspended carbon black and graphene nanoplatelets particles were studied. Carbon fillers were dispersed by simple shearing in a Couette type mixer and the resulting spin dope was extruded into a hot water coagulation bath from a single hole spinneret. Microstructure, mechanical properties, and electrical conductivity were assessed as a function of filler loading and discussed in comparison to melt spun fibers with similar fillers. The coagulation process and subsequent drying of wet spun fibers was found to produce a significant microporosity, more so the higher the filler loading. The electrical percolation threshold was quite high in the wet spun fibers and relatively modest values of conductivity were obtained with regard to the high filler loadings. Carbon black was found to be superior to graphene nanoplatelets. This was related to flow‐induced orientation effects. The mechanical properties of the carbon‐filled fibers were found to be similar or lower compared to the pure cellulose fibers because of low interfacial interactions and formation of microporosity. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41417.