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排序方式: 共有2700条查询结果,搜索用时 78 毫秒
41.
Virendra Mishra 《Materials and Manufacturing Processes》2018,33(14):1518-1530
The paper presents experimental investigations into electric discharge grinding (EDG) and ultrasonic vibration-assisted electric discharge grinding (UVAEDG) of Inconel 601. The process parameters selected for both processes were duty cycle, discharge current, pulse on time, grinding wheel speed, work speed, and speed ratio to study their influence on responses like surface roughness (Ra) and material removal rate (MRR). It was found that duty cycle, wheel speed, work speed, discharge current, speed ratio, and pulse duration significantly influenced MRR and Ra. It was inferred that MRR increased with increase in duty cycle, wheel speed, current, work speed, and pulse duration in both EDG and UVAEDG processes. It was also inferred that Ra increased with rise in duty factor, pulse on time, and discharge current in EDG and UVAEDG processes. 相似文献
42.
Fernando Maccari Tarini Prasad Mishra Monica Keszler Tobias Braun Esmaeil Adabifiroozjaei Iliya Radulov Tianshu Jiang Enrico Bruder Olivier Guillon Leopoldo Molina-Luna Martin Bram Oliver Gutfleisch 《Advanced Engineering Materials》2023,25(18):2300252
Flash spark plasma sintering (flash SPS) is an attractive method to obtain Nd–Fe–B magnets with anisotropic magnetic properties when starting from melt-spun powders. Compared to the benchmark processing route via hot pressing with subsequent die upsetting, flash SPS promises electroplasticity as an additional deformation mechanism and reduced tool wear, while maximizing magnetic properties by tailoring the microstructure—fully dense and high texture. A detailed parameter study is conducted to understand the influence of Flash SPS parameters on the densification and magnetic properties of commercial MQU-F powder. It is revealed that the presintering conditions and preheating temperature before applying the power pulse play a major role for tailoring grain size and texture in the case of hot deformation via Flash SPS. Detailed microstructure and magnetic domain evaluation disclose the texture enhancement with increasing flash SPS temperature at the expense of coercivity. The best compromise between remanence and coercivity (1.37 T and 1195 kA m−1, respectively) is achieved through a combination of presintering at 500 °C for 120 s and preheating temperature of 600 °C, resulting in a magnet with energy product (BH)max of 350 kJm−3. These findings show the potential of flash SPS to obtain fully dense anisotropic nanocrystalline magnets with high magnetic performance. 相似文献
43.
S. K. Mishra L. C. Pathak V. Rao D. Bhattacharya K. L. Chopra 《Journal of Superconductivity》1996,9(2):211-216
Critical current densities of the superconducting Y-Ba-Cu-O (YBCO) films have been observed to decrease with the increase of power of microwave radiation. Presence of Josephson type of junctions in the microbridges has been established from the microwave irradiation and magnetic field studies. BCS energy gap parameter (2/kT
c
) has been calculated from thedI/dV characteristics and found to be 3.7 at 13 K. 相似文献
44.
45.
An integrated intelligent computing model for the interpretation of EMG based neuromuscular diseases
Intelligent computing system (ICS) and knowledge-based system (KBS) have been widely used in the detection and interpretation of EMG (electromyography) based diseases. Heuristic-based detection methods of EMG parameters for a particular disease have also been reported in the literature but little effort has been made by researchers to combine rule-based reasoning (RBR) and case-based reasoning of KBS, and ANN (artificial neural nets) of ICS. Integrating the methods in KBS and ICS improves the computational and reasoning efficiency of the problem-solving strategy. We have developed an integrated model of CBR and RBR for generating cases, and ANN for matching cases for the interpretation and diagnosis of neuromuscular diseases. We have hierarchically structured the neuromuscular diseases in terms of their physio-pyscho (muscular, cognitive and psychological) parameters and EMG based parameters (amplitude, duration, phase etc.). Cumulative confidence factor is computed at different node from lowest to highest level of hierarchal structure in the process of diagnosis of the neuromuscular diseases. The diseases considered are Duchenne muscular dystrophy, Polymyostits, Endocrine myopathy, Metabolic myopathy, Neuropathy, Poliomyletis and Myasthenia gravis. The basic objective of this work is to develop an integrated model of RBR, CBR and ANN in which RBR is used to hierarchically correlate the sign and symptom of the disease and also to compute cumulative confidence factor (CCF) of the diseases. CBR is used for diagnosing the neuromuscular diseases and to find the relative importance of sign and symptoms of a diseases to other diseases and ANN is used for matching process in CBR. 相似文献
46.
Nishant Doshi Saru Kumari Dheerendra Mishra Xiong Li Kim-Kwang Raymond Choo Arun Kumar Sangaiah 《Multimedia Tools and Applications》2017,76(24):25893-25918
In this digital era, where Internet of Things (IoT) is increasing day by day, use of resource constrained devices is also increasing. Indeed, the features such as low cost, less maintenance, more adaptive to hostile environment, etc. make the wireless multimedia devices to be the best choice as the resource constrained devices. For the security, the end user device requires to establish the session key with the server before transferring the data. Mobile is one of the device having more and more usage as wireless multimedia device in recent years. In 2013, Li et al. proposed an efficient scheme for the wireless mobile communications and claimed it to be secure against various attacks. Recently, Shen et al. claimed that the scheme of Li et al. is still vulnerable to the privileged insider attack, the stolen verifier attack and finally proposed a scheme to withstand the mentioned and other attacks. However, in this paper we claim that the scheme of Shen et al. is still susceptible to the user anonymity, the session specific temporary information attack and the replay attack. In addition, Shen et al.’s scheme requires more time due to many operations. Further, we propose an efficient scheme that is secure against various known attacks and due to reduced time complexity our scheme is a preferred choice for the wireless mobile networks and hence for wireless multimedia systems. 相似文献
47.
In this paper, we investigate control strategies for a scalar, one-step delay system in discrete-time, i.e., the state of the system is the input delayed by one time unit. In contrast with classical approaches, here the control action must be a memoryless function of the output of the plant, which comprises the current state corrupted by measurement noise. We adopt a first order state-space representation for the delay system, where the initial state is a Gaussian random variable. In addition, we assume that the measurement noise is drawn from a white and Gaussian process with zero mean and constant variance. Performance evaluation is carried out via a finite-time quadratic cost that combines the second moment of the control signal, and the second moment of the difference between the initial state and the state at the final time. We show that if the time-horizon is one or two then the optimal control is a linear function of the plant’s output, while for a sufficiently large horizon a control taking on only two values will outperform the optimal affine solution. This paper complements the well-known counterexample by Hans Witsenhausen, which showed that the solution to a linear, quadratic and Gaussian optimal control paradigm might be nonlinear. Witsenhausen’s counterexample considered an optimization horizon with two time-steps (two stage control). In contrast with Witsenhausen’s work, the solution to our counterexample is linear for one and two stages but it becomes nonlinear as the number of stages is increased. The fact that our paradigm leads to nonlinear solutions, in the multi-stage case, could not be predicted from prior results. In contrast to prior work, the validity of our counterexample is based on analytical proof methods. Our proof technique rests on a simple nonlinear strategy that is useful in its own right, since it outperforms any affine solution. 相似文献
48.
Semantic web reasoners and languages 总被引:1,自引:0,他引:1
Semantic web reasoners and languages enable the semantic web to function. Some of the latest reasoning models developed in
the last few years are: DLP, FaCT, RACER, Pellet, MSPASS, CEL, Cerebra Engine, QuOnto, KAON2, HermiT and others. Some software
tools such as Protégé, Jena and others also have been developed, which provide inferencing as well as ontology development
and management environments. These reasoners usually differ in their inference procedures, supporting logic, completeness
of reasoning, expressiveness and implementation languages. Various semantic web languages with increasing expressive power
continue to be developed for describing web services. We survey the some of the more recent languages like OWL-S (Ontology
Web Language-Schema), WSML (Web Service Modeling Language), SWRL (Semantic Web Rule Language) and others that have been tested
in early use. We also survey semantic web reasoners and their relationship to these languages. 相似文献
49.
Creep fracture behaviour of pure aluminium-matrix composites with 10–30 vol% SiC particulates at 623 K is reported. A comparison of tensile and compression creep data shows the existence of a transition stress. Above this transition stress no steady state creep is observed in tension. This transition stress is related to a transition from intergranular to transgranular fracture. The origin of transition stress is perhaps associated with the diffusional relaxation of stress concentration at the matrix/particle interface by lattice diffusion. The intergranular creep fracture of composites appears to be similar to that of unreinforced aluminium and it is power-law creep controlled. The transgranular creep fracture occurs by void nucleation and growth. The nucleation strain for voids is quite small and hence the tertiary stage starts before the end of the primary stage. The ductile fracture models overestimate the strain to fracture and do not predict the observed stress dependence of strain to fracture. 相似文献
50.
Delayed settling of the ash particles and poor drainage of water from the pond ash are the major problems faced during the hydraulic stowing of pond ash. In this study the effect of polymeric flocculant on settling of the ash particles and drainage of water during pond ash stowing are investigated. In addition, the parameters, viz. drainage and absorption of water during pond ash stowing are quantified by stowing a mine goaf model with pond ash slurries of five different concentrations added with and without flocculant. The study revealed that addition of only 5 × 10?6 of Sodium Carboxymethyl Cellulose (Na-CMC) flocculant with the pond ash slurries during stowing offers best result in terms of quicker settling of the ash particles and enhanced water drainage from the hydraulically stowed pond ash. Besides, it resulted in drainage of more than 85% of the total water used in the initial 45 min of stowing. The improvement in drainage is caused due to coagulation and flocculation of the pond ash particles because of charge neutralization and particle–particle bridging. This study may provide a basis for estimating the drainage and absorption of water during the real pond ash stowing operation in underground mines. 相似文献