Using high-pressure torsion for the cold-consolidation of copper chips produced by machining

High-pressure torsion (HPT) was used to consolidate chips machined from coarse-grained copper and from copper processed by ECAP. The results are compared with discs prepared by HPT and with discs processed by a combination of equal-channel angular pressing (ECAP) and HPT. It is demonstrated that the consolidated discs have exceptionally fine microstructures and high hardness. The results suggest the possibility of a saturation in grain refinement which may be related to a release in heat during high-pressure straining.     

Effect of the deformation zone on the structure refinement in metals

Structure refinement in pure metals has been considered on the base of the concept of large deformations [1] with allowance for the role of intracrystallite and intercrystallite components. The effect of a parameter expressed as the ratio of the area of the deformation zone surface to its volume on the deformation mechanisms and the level of structure refinement has been demonstrated. A model of structure refinement in metals during cold deformation has been proposed.     

Usability and Feasibility of PmEB: A Mobile Phone Application for Monitoring Real Time Caloric Balance

Obesity is a major public health challenge with over 65% of US adults either overweight or obese. Estimated annual costs of obesity are $78.5 billion. Self-monitoring is a critical skill for successful weight management. However, self-monitoring is labor-intensive, and compliance is often difficult. In this paper, the authors describe the Patient-Centered Assessment and Counseling Mobile Energy Balance (PmEB) mobile phone application that allows users to self-monitor caloric balance in real time. The application was developed and applied in a four-phase iterative research and development methodology. A usability study and a preliminary feasibility study were conducted. The 1 month feasibility study measured compliance and satisfaction among a sample of 15 participants randomized to one of three groups: (1) a paper diary group, (2) a PmEB group with one daily prompt, and (3) a PmEB group with three daily prompts. PmEB scored highly on usability, compliance, and satisfaction. In addition, mobile phone group users scored PmEB the same as or better than Paper Group members scored the paper diary in nearly all categories. Thematic analysis of comments revealed very positive reviews of PmEB as well as areas for improvement. PmEB is both usable and feasible for weight management self-monitoring, and the iterative pilot study methodology was effective in improving its usability.     

Effect of the Type of Crystal Lattice of Metals on Structure Formation and Mechanical Properties Under Plastic Shear Deformation

Metal Science and Heat Treatment - The structural state and the post-deformation mechanical properties of steel 10 (bcc), copper M1 (fcc) and titanium Grade 4 (hcp) are studied using the method of...     

Validation of a computer model for solar assisted district heating systems with seasonal hot water heat store

The TRNSYS XST-model for the calculation of the thermal behaviour of ground buried hot water heat stores was validated. For the validation procedure measured data of the seasonal hot water heat store in Hannover (Germany) were used. In contrast to previous investigations the temperatures of the surrounding ground were also taken into consideration. The determination of the heat store parameters was carried out using TRNSYS in combination with the parameter identification software DF. The deviation between measured and calculated temperatures is less than ±3%. The measured and calculated heat quantities are also in good agreement (annual deviation less than 2%). The validated XST-model was integrated into a TRNSYS model to calculate the thermal behaviour of the solar assisted district heating system in Hannover in 2002. The deviations between measured and calculated heat quantities do not exceed 5%.     

Some Interactions Between Gelatin and Surfactants

Abstract

The interactions between gelatin and sodium dodecyl sulphate (SDS) were studied with respect to the viscosity increase. Beside the temperature, pHand SDS concentration, we learned that the starting viscosity is of importance. Obviously, the high molecular parts have a major influence. These interactions can be suppressed by a suitable modification.     

Java-basiertes automatisiertes Test-Framework

Java-based Automated Test-Framework With an increasing number of software-systems built using components, software developers are faced with entirely new challenges. For example, testing these modu-lar systems has become far more complex. Manual test approaches are incapable of dealing with the new architectures, leaving several parts of the systems untested. Thorough tests require extensive use of human resources, with enormous financial repercussions. Most customers are unwilling to accept these, completely unaware of their eventual benefit. Even existing automated software test approaches can only remedy these problems in parts. They commonly require source code access to add the necessary test routines, making the approach unsuitable for third party compo-nents. The innovative CBTesten approach tackles this problem. A highly dynamic framework is introduced into the software-system after compilation, which allows de-riving of test cases as well as fully automated tests based on the collected data.     

Structure development in oriented polyethylene films and microporous membranes as monitored by sound propagation

Microporous membranes of high‐density polyethylene were prepared by melt‐extrusion followed by annealing and uniaxial extension. Crystallization at a high melt flow rate and subsequent annealing of the spun films with fixed ends led to the formation of oriented hard‐elastic materials with a high modulus of elasticity and a considerable work recovery. Uniaxial stretching of such systems along the orientation direction induced the formation of microscopic pores due to the specific structure of the hard‐elastic material. At some critical values of the processing parameters, through‐flow channels were formed, converting the film into a microporous membrane permeable to liquids and vapors. Sound propagation, tensile measurements, and X‐ray diffraction techniques were used to characterize the structure and properties of the samples at individual stages of the process as a function of the processing parameters. In particular, it was shown that polar diagrams of the sound propagation velocity reflect sensitively the structural changes in the process of porous structure formation. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 214–222, 2001