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71.
72.
ABSTRACT Equipment availability is the most significant factor in the productivity of many mines and processing plants. Machine breakdowns are not only expensive in terms of production losses but also important in meeting production schedules. In the case of an equipment breakdown, a large portion of the downtime is spent in locating the fault. For this reason, it is felt that an automated method is needed to assist the operator in the diagnostic process. In this paper, a diagnostic procedure is developed by modelling the partially known or imprecise relations and poorly defined variables found in a diagnostic environment. A diagnostic algorithm which relates the possible causes of a failure to their respective symptoms through fuzzy logic paths is presented. Application of the algorithm is illustrated by a simple example. 相似文献
73.
A case of unicystic ameloblastoma which recurred after 15 years showing unusual histological features is reported. The prominent pseudo-glandular features present are described. This case highlights the importance of extensive histological examination for more characteristic features of ameloblastoma to reach a correct diagnosis. 相似文献
74.
L. E. Kar’kina I. N. Kar’kin Yu. N. Gornostyrev 《The Physics of Metals and Metallography》2006,101(2):130-140
Size effect in Fe-Ni-alloy nanoclusters has been studied by the molecular-dynamics (MD) method using multiparticle interatomic interaction potentials. It is shown that the α-γ transformation in nanoparticles with sizes d>3.5 nm proceeds by the mechanism of nucleation at grain boundaries and propagation of fcc-phase plates. As a result of the transformation, a twinned lamellar domain structure is formed. In particles with sizes 3.0<d<3.5 nm, the α-γ transformation is accompanied by radial-symmetry atomic movements that are close to those characteristic of the Bain scheme. This results in the formation of a single-domain fcc phase. In nanoparticles with sizes 1.5<d<3.0 nm, the α-γ transformation proceeds via an intermediate state that is retained within a temperature range of a few hundreds of kelvins and is characterized by an incomplete phase transformation. It has been found that in Fe-Ni clusters with sizes d≤1.5 nm, the α-γ transformation does not occur. During heating, the initial bcc configuration turns into an icosahedral one through polytetrahedral or amorphous-like configuration. 相似文献
75.
For the accurate prediction of the performances of saturated synchronous machines, the saturation characteristics in both the direct and quadrature axes are needed. The d-axis saturation characteristic of a synchronous machine can be measured easily by the open-circuit test with the machine excited from its field winding. On the other hand, the q-axis saturation characteristic of a synchronous machine cannot be measured applying a similar easy, simple method and, as a result, these characteristics are usually not experimentally measured and are not available. In this paper, three possible experimental methods for determining the q-axis saturation characteristics of both cylindrical-rotor and salient-pole synchronous machines are presented. The merits and demerits of these experimental methods are discussed from the point of view of their complexity and their accuracy. Comparisons between the measured q-axis saturation characteristics obtained by these experimental methods are made for a cylindrical-rotor machine and two salient-pole machines. Moreover, the various sources of errors, which may affect the accuracy of determining the q-axis saturation characteristics by these methods, are investigated. 相似文献
76.
A mathematical analysis describing the densification of ceramic coating processed with a moving TEM00, mode laser beam has been presented in this paper. Calculations of the depth of the heat affected zone in ZrO2, A12O3 and TiO2 ceramic substances is performed by adopting a three-dimensional quasi-steady state heat conduction model based on the mechanism of viscous solid-phase densification. Also, a working range for these ceramics coating densification is predicted by varying the laser beam power, spot size and scanning velocity. The heat-affected layer in ZrO2 compact is found to be confined within a depth of 50 μm from the surface and it is fully densified for grains of initial radius 5 μm. A simple expression for temperature distribution is presented, which is found to provide sufficiently accurate estimates within a limited region around the laser spot. 相似文献
77.
Asheesh Kumar Raghunandan Sharma Chhatrasal Gayner Siddanathi Nageswara Rao Devendra P. Singh Malay K. Das Kamal K. Kar 《International Journal of Applied Glass Science》2017,8(1):97-104
The (AgBr)x(LiPO3)(1−x) (x=0.4 and 0.5) and [(AgI)x(AgBr)0.4−x](LiPO3)0.6 (x=0.1, 0.2, and 0.3) superionic electrolytes have been prepared by conventional melt quenching using a twin roller. These electrolytes are characterized by X-ray diffraction, SEM, and energy dispersive X-ray analysis (EDAX) for structural investigation. Electrical characterizations have been carried out by the AC impedance analysis. The conductivity of LiPO3 glassy system at room temperature is improved by doping with the silver bromide (AgBr)x(LiPO3)(1−x) and the mixture of silver iodide, silver bromide (AgI-AgBr-LiPO3 system) up to 10−5 and 10−3 Ω−1 cm−1, respectively (improvements by four or five orders of magnitude). The frequency response of ionic conductivity has been analyzed by universal dynamic response model (Jonscher's law) and AC conductivity data are fitted using the Jonscher's power law. The conductivity values obtained by the power law and impedance plots are comparable. The frequency exponent (n) has a value between 0 and 1. The AgI-AgBr-LiPO3 system shows the mixed alkali effect. Summerfield scaling master curve is temperature dependent, which may be due to the contribution of the both lithium and silver ions to ionic conduction. 相似文献
78.
Bishnu Prasad De R. Kar D. Mandal S. P. Ghoshal 《International Journal of Numerical Modelling》2016,29(5):873-896
This paper presents an efficient approach for the optimal designs of two analog circuits, namely complementary metal oxide semiconductor) two‐stage comparator with p‐channel metal oxide semiconductor input driver and n‐channel input and folded‐cascode operational amplifier using a recently proposed meta‐heuristic‐based optimization algorithm named as colliding bodies optimization (CBO). It is a multi‐agent algorithm that does not depend upon any internal control parameter, making the algorithm extremely simple. The main objective of this paper is to optimize the metal oxide semiconductor (MOS) transistors' sizes using CBO in order to reduce the areas occupied by the circuits and to get better performance parameters of the circuits. Simulation Program with Integrated Circuit Emphasis simulation has been carried out by using the optimal values of MOS transistors' sizes and other design parameters to validate that CBO‐based design is satisfying the desired specifications. Simulation results demonstrate that the design specifications are closely met and the required functionalities are achieved. The simulation results also confirm that the CBO‐based approach is superior to the other algorithms in terms of MOS area and performance parameters like gain, power dissipation, etc., for the examples considered. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
79.
80.
A new AFM (atomic force microscopy) nanotribology method using a T-shape cantilever with an off-axis tip (Nat Nanotechnol
2:507–514, 2007) has been developed for measuring friction coefficient at nanometer scale. In this method, signals due to both bending and
twisting of the T-shape AFM cantilever are detected simultaneously. For a T-shape AFM cantilever, the bending is caused by
the normal load and the twisting is caused by both the normal and the lateral loads. The twisting generated by the normal
load is calibrated in advance. Consequently, the twisting only due to the lateral load can be decoupled from the total lateral
voltage signal. And the friction coefficient can be finally determined based on a conversion relationship between the normal
and lateral voltage signals of the AFM photodetector. A practical procedure for minimizing Abbé error in friction coefficient
measurement has also been introduced. The proposed new method is simple and accurate, and requires the least operation for
friction coefficient measurement at nanometer scale. 相似文献