Long time behaviour of the solution of a system of equations from new theory of shock dynamics

The new theory of shock dynamics gives a system of n + 2 equations, the solution of which determines the propagation of a discontinuity in the initial condition. For the model equation u_t + u u_x = 0, the long time behaviour of the solution is investigated for various confined initial data. The suitability of using Padé approximants for the solution is examined. Special exact solutions are obtained.     

Skeletal muscle fatigue and physical endurance of young and old mice

In order to evaluate the role played by muscular and extramuscular factors in the development of fatigue in old age, the time course of fatigue in isolated skeletal muscles and spontaneous motor activity and endurance of whole animals were monitored using young (3-6 months) and old (34-36 months) CF57BL/6J mice. The isolated extensor digitorum longus (EDL) and soleus muscles from old mice had smaller (P < 0.05) mass and developed lower (P < 0.02) maximal tetanic tension at 100-Hz stimulation than the muscles of young mice. During stimulation at 30 Hz every 2.5 s, a 50% decline in original tetanic tension occurred by 109 s in young EDL and 129 s in old EDL, but by 482 s in young soleus and 1134 s (projected) in old soleus, indicating more (P < 0.05) resistance to fatigue in old than young soleus. However, the old mice showed significantly fewer (P < 0.002) spontaneous ambulatory movements than the young mice. On a treadmill with a belt speed of 10 m/min at an inclination of 0 degrees, the old mice could only run for 22 min compared to 39 min ran by young mice (P < 0.02). They took more rest periods (P< 0.02) than the young mice. In a quantitative swimming monitor, the old mice swam for a shorter (P < 0.05) time than young mice (20.4 min compared to 28.6 min). Integrated swimming activity at 20 min was smaller (P < 0.05) in old mice than in young mice (413 g/s compared to 628 g/s). Hence increased fatigue in old age is not caused by impairment of processes within the muscles, but by impairment of central or extramuscular processes.     

Cost-sensitive partitioning in an architecture synthesis system for multicluster processors

Application-specific instruction processors (ASIPs) have great potential to meet the challenging demands of pervasive systems. This hierarchical system automatically designs highly customized multicluster processors. In the first of two tightly coupled components, design space exploration heuristically searches the basic capabilities that define the processor's overall parallelism. In the second, a hardware compiler determines the detailed architecture configuration that realizes the parallelism.     

Multi-media instructional approach to teaching linear programming

This paper describes different strategies employed in converting a lecture-oriented mathematical programming course to a Personalized Self-Paced Instructional (PSI) format. This is an elective course for students in science, engineering and management. A multi media instructional approach is used in the PSI system which combines traditional lectures, self-paced and individualized learning assisted by interactive computer programs and video taped instructional materials. This unique PSI system for mathematical programming provides maximum learning opportunity and flexibility to students. The author's experiences with the PSI system and the students' evaluation of the self-paced system are also discussed.     

Preparation of new niobates with the rutile structure

CrVNbO₆, FeVNbO₆ and NiV₂Nb₂O₁₀ have been prepared. The compounds are isostructural with the rutile phase of FeNbO₄, are nonstoichiometric with respect to all three constituent metal atoms, and show appreciable electrical conductivity.     

Characterization of zinc-nickel alloy electrodeposits obtained from sulphamate bath containing substituted aldehydes

Zinc alloy offers superior sacrificial protection to steel as the alloy dissolves more slowly than pure zinc. The degree of protection and the rate of dissolution depend on the alloying metal and its composition. Zinc-nickel alloy may also serve as at less toxic substitute for cadmium. In this paper the physico-chemical characterization of zinc-nickel electrodeposits obtained from sulphamate bath containing substituted aldehydes was carried out using hardness testing, X-ray diffraction, and corrosion resistance measurements. The corrosion behaviour of these samples in a 3.5% NaCl solution was examined. The decrease inI _corr and high charge transfer resistance indicated the improved corrosion resistance of these deposits.     

Gel and Pasting Behaviour of Fenugreek‐Wheat Starch and Fenugreek – Wheat Flour Combinations

The influence of fenugreek material on starch and flour rheological characteristics was determined. Ground fenugreek grain material, and a purified fenugreek extract (Fenulife®) were used as replacement or as addition to flour or starch. Evaluation of the pasting properties of starch and flour fenugreek mixtures illustrated that fenugreek addition increased the peak and final viscosity of the mixtures in relation to the level of fenugreek addition used. The ground fenugreek seeds yielded a lower response than the purified Fenulife® sample, due to the presence of protein, starch and other polysaccharide material in the ground flour. Rheology of the pastes showed that the addition of fenugreek material (especially Fenulife®) increased the viscoelastic nature of the material. Textural analysis of the cooled gels illustrated that the inclusion of fenugreek into flour mixes generally raised the hardness of the gels, although the gels became softer with higher levels of fenugreek material used. The inclusion of fenugreek into starch gels showed similar patterns of pasting and textural properties, with a general decrease in texture related to the level of fenugreek included.     

A New Hot Tearing Assessment by Using Stepped Ring Core Mold and the Effect of Strontium on the Hot-Tearing Resistance of Al–6 wt% Zn Based Alloy

Automobile and aerospace industries use thin wall aluminium alloy castings which provide lighter structures with excellent mechanical properties. Production of thin wall castings is more challenging due to hot tear formation. Lack of fluidity in molten alloy causes hot tears and must be addressed in thin wall castings of Al-alloys. The present study is focused on a new technique known as stepped ring mould casting. It is possible to assess the hot tear susceptibility of Al–6Zn alloys by varying ring thickness to find out the critical thickness for occurrence of hot tears. The alloy was cast using different strontium (Sr) concentrations (0.2, 0.4, 0.6%). Effects of strontium concentrations were studied in terms of fluidity, porosity content, microstructure and tensile properties of Al–6Zn alloy. In the present work, unmodified and Sr modified alloy casts were characterized by SEM, EDS and XRD respectively. Al–6Zn ingots were procured by master alloy route. Repetition of stepped ring test on the critical thickness showed that hot tear were successfully eliminated significantly due to the addition of Sr. On the other hand, 0.6% Sr also exhibited a good amount of porosity and decrease in elongation. Shorter fluidity length was observed in 0.2% Sr modified alloy. Mechanical and metallographic tests revealed that the alloy castings modified with 0.4% Sr offered better results in yield strength, less porosity and an improved hot tear resistance at micro and macro levels.