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81.
Anton?ShterenlikhtEmail author Sayyed?H.?Hashemi John?R.?Yates Ian?C.?Howard Robert?M.?Andrews 《International Journal of Fracture》2005,132(1):81-97
The dynamic responses of the standard Charpy impact machine were studied experimentally using strain gauges and accelerometer attached to the striker and the rotary position sensor fixed at the rotating axis and numerically with the finite element analysis. The fracture propagation was simulated with the cellular automata finite element approach developed earlier. A series of low velocity as well as full capacity Charpy tests were analysed. It was found that the strain gauge signal recorded close to the tup edge and the acceleration recorded at the back of the striker do not match. The energy calculated with the strain gauge data agrees well with the dial reading, while the energy calculated with the accelerometer signal is never near it. Frequencies close to the first natural \hbox{frequency} of the Charpy sample have high modal magnitudes in the acceleration signal but are effectively damped in the strain gauge response. Vibrations of the striker arm have highest modal magnitudes in the rotary position sensor. A low-pass filter is used to obtain the striker movements. The finite element analysis partly supports the experimental observations but also suggests that acceleration at the tup edge suffers higher oscillations than strain. 相似文献
82.
2 hypotheses were tested with the Block Design subtest of the Wechsler Intelligence Scale and the Drawing Version of the Block Design Rotation Test: (1) Brain-damaged patients rotate significantly more than non-brain-damaged patients, and (2) The factors influencing rotation in the blocks test would be the same in the drawing version. Ss consisted of 20 brain-damaged patients, 25 non-brain-damaged psychiatric patients, and a control group of 25 normal persons. It was found that rotation effects in a drawing version of a task requiring the copying of designs discriminated between brain-damaged and non-brain-damaged Ss. The relative influence of the factors affecting the appearance of the rotation effect in all Ss was shown to be different in the drawing version than in the blocks version. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
83.
B. Yates B. A. McCalla J. P. Sargent K. F. Rogers D. M. Kingston-Lee L. N. Phillips 《Journal of Materials Science》1978,13(10):2226-2232
Measurements of the principal linear thermal expansion coefficients of a tridirectional (–45°, 0°, +45°) carbon fibre reinforced plastics laminate are reported in the approximate temperature range 90 K to 500 K. A quantitative evaluation of the in-plane results in thermoelastic terms has yielded an agreement with these results consistent with the approximations and uncertainties involved. The qualitative agreement with expectations based upon the behaviour of unidirectional and bidirectional laminates is also demonstrated. The account concludes with an examination of some effects which are peculiar to multidirectional laminates. 相似文献
84.
Mailed 8 different types of requests for research participation to psychologists and psychiatrists (N = 412) employed in Canadian mental health facilities. There was a better response to requests for participation as research Ss than to more informal appeals. Responsivity was inversely related to expected visibility, including lack of anonymity of response. Results suggest that fear of evaluation largely determined response rates in studies soliciting clinicians to participate in research. (French summary) (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
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Yates Sorrell F. Seungil Yu Kiether W.J. 《Semiconductor Manufacturing, IEEE Transactions on》1994,7(4):454-459
A simulation of a complete rapid thermal processing (RTP) system is made to investigate the accuracy of various techniques for temperature control. The process simulated was the chemical vapor deposition (CVD) of polycrystalline silicon over an oxide. Control strategies considered were, open loop control, pyrometer control, pyrometer control with a correction for emissivity changes produced by CVD, and open loop control with the lamp heating programmed as a function of time, based an model predictions. The temperature variation and final film thickness of each was predicted by the simulation. The results indicate that model-based open loop control is viable strategy for practical RTCVD control. Based on this strategy, model-based open loop control was then implemented for the control of an existing RTP system. The experimental results confirm the simulations and provide improved temperature control for RTCVD 相似文献
88.
CRACK PROPAGATION UNDER MIXED MODE (I + III) LOADING 总被引:1,自引:0,他引:1
J. R. Yates R. A. Mohammed 《Fatigue & Fracture of Engineering Materials & Structures》1996,19(10):1285-1290
Abstract— In this paper are presented the results of fatigue crack propagation tests on angled-slit, three point bend mixed-mode (I + III) specimens manufactured from a low pressure steam turbine rotor forging. The path of crack propagation has been studied for two mixed mode (I + III) loading conditions. It has been observed that crack growth occurs by a mode I mechanism and a model has been developed to correlate crack growth rates in mixed mode (I + III) specimens with data from pure mode I fatigue tests. 相似文献
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A fault-tolerant microprocessor system designed to provide digital control for an active magnetic bearing is described. This particular control problem demands significant processing power, is easily divided into relatively independent parallel tasks, and cannot tolerate controller failures. The overall system requirements and architecture are described, as is the design of the digital control module and the analog I/O board. The fault tolerance of the system is evaluated. Extensive computer simulations of system reliability models verified that the design satisfies all of the reliability requirements. Although the system was designed for a specific problem, much effort was expended to make it general enough for applications to a wide range of real-time applications 相似文献