Technology combats disabilities

The author focusses on advances in equipment that offset physically functional limitations. He discusses how disabled and elderly people are using aids that enhance mobility (walking a certain distance, lifting a weight, or climbing stairs) as well as sensory faculties (seeing print, hearing conversation, and speaking intelligibly)     

a-Si alloy three-stacked solar cells with high stabilized-efficiency

a-Si alloy three-stacked solar cells have been studied to improve the stabilized efficiency of a-Si: H based solar cells. Based on the analysis by the individual characterization method of the component cells in stacked type cells, the a-Si :H middle cell was replaced with an a-SiGe :H cell. Furthermore, the optical confinement technology was improved to obtain a high-output current with thin i-layer thickness in the a-SiGe :H bottom cell. By this device design, the initial conversion efficiency was improved up to 12.4% and more than a 10% stabilized efficiency was obtained in a-SiC :H/a-SiGe :H/a-SiGe :H three-stacked cells. These cell characteristics were confirmed by measurements at the JQA Organization (the former JMI Institute).     

Resonance assignment of methionine methyl groups and chi 3 angular information from long-range proton-carbon and carbon-carbon J correlation in a calmodulin-peptide complex

Several simple 3D experiments are used to provide J correlations between methionine C epsilon methyl carbons and either the C gamma H2 protons or C beta and C gamma. The intensity of the J correlations provides information on the size of the three-bond J couplings and thereby on the chi 3 torsion angle. In addition, a simple 3D version of the HMBC experiment provides a sensitive link between the C epsilon H3 methyl protons and C gamma. The methods are demonstrated for a 20 kDa complex between calmodulin and a 26-residue peptide fragment of skeletal muscle myosin light chain kinase.     

Aortic valve papillary fibroelastoma. A diagnosis by transthoracic echocardiography

Cardiac papillary fibroelastomas are unusual, frond-like growths typically found on cardiac valves, diagnosed incidentally on autopsy or cardiac surgery, but rarely during life. We report a rare case of an aortic valve papillary fibroelastoma detected by transthoracic echocardiography and confirmed by histologic study.     

An anomalous acoustic effect during martensite transformations in NiTi-based alloys

Martensite transformations proceeding in mechanically loaded TiNi-based alloys account for an “anomalous” character of the acoustic emission from the material, whereby cyclic transformations during the growth of mechanical stress in the course of the direct transition is accompanied by an increase, rather than by a decrease, in the acoustic emission energy. This behavior of the acoustic emission is evidence of a significant influence of the external stresses on the martensite transformations and the related energy dissipation process.     

Photoelectric properties of planar structures with double Schottky barrier treated in a high-vacuum microwave discharge

The state of the surface of n-GaAs crystals upon high-vacuum microwave plasmachemical (HVMWPC) etching in various gas mixtures and the influence of the semiconductor surface condition on the photoelectric characteristics of related metal-semiconductor-metal structures with double Schottky barrier (MSMDSB structures) are investigated. Dependence of the HVMWPC etching rate of the GaAs surface on the gas mixture composition and substrate temperature is determined. It is shown that the HVMWPC etching regime strongly influences the photoelectric properties of MSMDSB structures: the treatment can lead to either growth or drop in photosensitivity of the samples. Optimum etching regimes are established for which good semiconductor surface quality and high photosensitivity of the MSMDSB structures are retained at a high etching rate.     

Characteristics of hydrostatic bearing/seal parts for water hydraulic pumps and motors. Part 1: Experiment and theory

In this paper, the load-carrying capacity, power losses and stiffness of disk-type hydrostatic thrust bearings including the case of eccentric loading are discussed theoretically. The numerical analysis method is established based on a two-dimensional elastohydrostatic problem with an elastic deformation model, which is extended to adapt it for a non-axisymmetric load acting on the thrust bearing. The bearing is made of a combination of stainless steel/stainless steel and stainless steel/plastics. For the elastic materials, the maximum stiffness derived from, i.e., minimum film thickness is, larger than that of the rigid material in the range of a large ratio of pocket pressure and a hydrostatic balance ratio of over unity, which is defined as the ratio of the load to the maximum hydrostatic load-carrying capacity. The maximum load-carrying capacity and minimum power loss can exist in the domain of the hydrostatic balance ratio over unity for the case of the bearing consisting of elastic/rigid materials, in comparison with that composed of the same rigid materials. For the case of water, the power loss due to leakage flow is slightly larger but that due to frictional torque is much smaller than that in the case of hydraulic oil. Then, the total power loss is much smaller than that of hydraulic oil.     

Climatic solar roof: an ecological alternative to heat dissipation in buildings

A new system based on the harnessing of solar and wind power is presented for heat dissipation in air conditioning facilities. The innovation offered by the new system is the integration of two well-known subsystems: a cooling tower and a solar chimney which increases the air flow without the use of electric power. The system is described and presented together with a model for its study. The field data acquired from the prototype built in southern Spain establishes the actual potential of the system, which provides a new approach to a sustainable technological development.