Wyniki wyszukiwania - BazTech

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Effects of bench step exercise intervention on work ability in terms of cardiovascular risk factors and oxidative stress: a randomized controlled study

Ohta M., Eguchi Y., Inoue T., Honda T., Morita Y., Konno Y., Yamato H., Kumashiro M.

International Journal of Occupational Safety and Ergonomics

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2015

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Vol. 21, No. 2

141--149

EN

Work ability is partly determined by physical and mental fitness. Bench step exercise can be practiced anywhere at any time. The aim of this study was to determine the effects of a bench step exercise on work ability by examining cardiovascular risk factors and oxidative stress. Thirteen volunteers working in a warehousing industry comprised the bench step exercise group (n = 7) and the control group (n = 6). The participants in the step exercise group were encouraged to practice the step exercise at home for 16 weeks. The step exercise improved glucose metabolism and antioxidative capacity and increased work ability by reducing absences from work and improving the prognosis of work ability. The improvement in work ability was related to a reduction in oxidative stress. These results suggest that a bench step exercise may improve work ability by reducing cardiovascular risk factors and oxidative stress.

2

A simple local navigation system inspired by hippocampal function and its autonomous mobile robot implementation

Miki T., Hayashi H., Goto Y., Watanabe M., Inoue T.

Journal of Automation Mobile Robotics and Intelligent Systems

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2010

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Vol. 4, No. 2

31-38

EN

We propose a practical simple local navigation system inspired by the sequence learning mechanism of the entorhino-hippocampal system. The proposed system memorizes a route as sequences of landmarks in the same way humans do. The proposed local navigation system includes a local route memory unit, landmark extraction unit, and learning-type matching unit. In the local route memory unit, the concept of the sequence learning mechanism of the entorhino-hippocampal system is implemented using a fully connected network, while a sequence of landmarks is embedded in the connection matrix as the local route memory. This system has two operation modes: learning and recall modes. In learning mode, a sequence of landmarks, i.e. a local route, is represented by enhanced loop connections in the connection matrix. In recall mode, the system traces the stored route comparing current landmarks with the stored landmarks using the landmark extraction and learning-type matching units. The system uses a prospective sequence to match the current landmark sequence with the recalled one. Using a prospective sequence in the route comparison allows confirmation of the correct route and deals with any slight change in the current sequence of landmarks. A certainty index is also introduced for judging the validity of the route selection. We describe a basic update mechanism for the stored landmark sequence in the case of a small change in the local route memory. The validity of the proposed system is confirmed using an autonomous mobile robot with the proposed navigation system.

3

Development of micro ceramic gas turbine based on mini jet engine

Yoshida H., Sodeoka S., Iki N., Matsunuma T., Inoue T., Suzuki M., Ebara T., Lee Y.

Prace Naukowe Politechniki Warszawskiej. Konferencje

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2005

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z. 24

365--374

EN

Ceramic Gas Turbine can achieve high thermal efficiency without cooling system of turbine blades. However, ceramic elements are too expensive for development and introduction stage. Thus a hybrid type gas turbine of ceramic parts and metal parts are designed and manufactured. The hottest parts i.e., a turbine nozzle and rotor are replaced to ceramic type. But its combustor is still made of metal. The baseline machine is a small single-shaft turbojet engine (J-850, Sophia Precision, Co., Ltd.) with a centrifugal compressor and a radial turbine. An Inconel 713C alloy turbine rotor was replaced into a ceramic rotor (SN-235, Kyocera Corporation). The Inconel turbine nozzle and casing were replaced into the ceramic parts (SN-01, Otsuka Ceramics Co., Ltd.). The ceramic nozzle and case is supported by metal parts. As a first step, only turbine rotor was replaced with a ceramic rotor. A test operation was conducted at rotating speeds of up to 140,000 rpm in atmospheric air. As a second step, the Inconel turbine nozzle and turbine nozzle casing were replaced with ceramic parts. The ceramic nozzle and case were supported by metal parts. Through tests with the ceramic nozzle, it became evident that one of the key technologies for the development of ceramic gas turbines is the design of the interface between the ceramic components and the metallic components, because the difference between the coefficients of linear thermal expansion of the ceramic and metal produces large thermal stress at their interface in the high-temperature condition. Therefore a buffer material made of alumina fiber was inserted at the interface between the ceramic and metal. However alumina fiber is not tough enough for repeat of assembly and disassembly. The metallic spring ring seal can be applied instead of the alumina fiber, because the wall temperature of the combustor is not as high as the turbine inlet temperature due to the cooling effect of the combustion air. This metallic seal and the ceramic rotor were assembled into the gas turbine. This engine could operate for 1 hour in the condition that the estimated turbine inlet temperature was over 1000 °C.

4

Macro- Meso- and Micro-scopic Metallo-Thermo-Mechanics - Application to Phase Transformation Incorporating Process Simulation

Inoue T.

Inżynieria Powierzchni

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2005

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Nr 1

23-35

EN

Three kinds of approach from macro- meso- and micro-scopic viewpoints are summarized in this paper, relevant to simulating the phase transformation incorporating processes. Since the fields of material structure, temperature and stress/strain induced in a body in such process are coupled each other, the ordinal way to solve independent (or, uncoupled) governing equations for transformation kinetics, heat conduction and stress analysis is insufficient, but thermodynamics-based consideration is needed to obtain the coupled equations among three fields. A transformation parameter indicating progressive phase change is introduced as one of internal parameters representing volume fraction of each phase or phase field parameter, and governing three kinds of equation for the parameter, Fourier law and stress-strain constitutive equation are derived. Thus obtained equations are applied to formulate the macroscopic finite element scheme and also the phase field method in meso-scopic sense in the framework of continuum thermodynamics. The molecular dynamics approach is also carried out to evaluate microscopic, or physical aspect of the fields. Some examples of the computer simulated processes with phase transformation are illustrated based on such three kinds of approach.

PL

W artykule przedstawiono trzy sposoby oceny przemian fazowych w metalach, tzn. w skali: makro-mezo i mikroskopowej, uwzględniając przy tym proces symulacji komputerowej. Ponieważ w strukturze materiału zaznacza się wpływ temperatury, nacisków oraz naprężeń własnych i to w całej jego objętości, a procesy te są wzajemnie powiązane, toteż stosowany zazwycząj sposób rozwiązania analitycznego z użyciem niezależnych wzorów dotyczących kinetyki przemian, przewodnictwa cieplnego czy rozkładu naprężeń własnych, okazał się niewystarczający. W tej sytuacji niezbędnym się stały rozważania bazujące na termodynamice i pozwalające na uzyskanie zależności łączących przemiany fazowe zachodzące w trzech rozważanych obszarach, tj. skali: makro-mezo- i mikroskopowej. W tym celu sformułowano m. in. parametr wewnętrzny przemian charakteryzu jący zmiany fazowe, a reprezentujący objętościowe części poszczególnych faz i związany z trzema rodzajami równań wyprowadzonych dla rozważanych obszarów. Równania te wyprowadzono korzystając z prawa Fouriera oraz równań konstytutywnych dla nacisków i naprężeń własnych. Wyprowadzone równania zastosowano do utworzenia schematu przemian w skali makroskopowej - metodą elementów skończonych oraz schematu przemian w skali mezoskopowej metodą pól fazowych w ramach continuum termodynamicznego. Molekularno-dynamiczne podejście zostało przyjęte dla wykonania obliczeń w skali mikroskopowej. W artykule podano również przykłady symulacji komputerowej procesów z przemianami fazowymi, bazując na trzech przjętych sposobach podejścia, tj. dla skali: makro-mezo- i mikroskopowej.