Profit evaluation of a two-unit system with internal and external repairs, inspection and post repair

In practice, systems do not always fail with a major breakdown, needing a heavy repair from some external source. Quite often, systems have a minor fault for which an immediate internal repair is more appropriate, in terms of availability of the system and economy, than calling a repairman from some external repair facility, waiting idly for his arrival or making a call with a higher cost. The present work discusses two non-identical unit systems with two types of repair, the internal and the external one. The external repair is called only when the internal staff fail to do the job. In the case of external repair, there is a provision of inspection, wherein if the repair is found unsatisfactory, it is sent for post repair. Using the regenerative point technique, various reliability characteristics of system effectiveness have been obtained.     

Multi-stage point estimation of the common location parameter of several exponential distributions

The problem of point estimation of the common location parameter of several exponential distributions is considered. The scale parameters are assumed to be unknown and unequal. Consideration is given to a family of loss functions. Non-existence of the fixed sample size procedure is established to deal with the present estimation problem. Purely sequential, accelerated sequential, three-stage and two-stage procedures are developed to handle the situation. Relative advantage and disadvantage of these estimation approaches are established.     

Development of elastomer blends for specific defence application

Several aspects of butyl (CIIR)-polychloroprene (CR) rubber blends viz (i) phase morphology evolution with respect to varied blend ratios and the effect of compatibilizer, (ii) processing characteristics, (iii) vapour impermeability and flame retardancy, (iv) mechanical properties, (v) ageing characteristics and (vi) the effect of addition of fillers into these blends have been studied. Scanning electron microscopy (SEM) has been used as a tool to investigate the phase morphology and also the failure mechanism. Blends based on CR and CIIR are likely to be important to Defence services for developing several rubber products with the above properties and characteristics. Paper presented at the poster session of MRSI AGM VI, Kharagpur, 1995     

Adaptive control of aircraft in windshear

The control of an aircraft encountering windshear after takeoff is treated as a problem of stabilizing the climb rate about a desired value. An adaptive strategy is developed which uses only climb rate information. Robustness vis à vis windshear structure and intensity is illustrated via simulations employing four different windshear models.     

Noncoherently orthogonal digital phase modulation

This work considers noncoherently orthogonal signaling with full response digital phase modulation and focuses on the phase function shaping problem. A criterion for the phase function that ensures noncoherent orthogonality of the modulated signal over one symbol interval is introduced. Furthermore, a new family of phase modulated signals is presented. This new orthogonal modulation format lacks the well-known spectral lines of noncoherently orthogonal FSK and hence uses the power efficiently to convey information     

An Equation of State for High-Temperature Superconductors

In the present paper the expression of cohesive energy and the bulk modulus as a function of volume are formulated for high-T _c copper oxide superconductors. The model employed consists of long-range electrostatic Coulomb interaction and short-range overlap repulsion. The short-range overlap potential is considered in the Born-Landé inverse power form. The model parameters of the Born-Landé model are calculated from the equilibrium condition and data of bulk modulus at room temperature. The computed values of the pressure derivatives of the bulk modulus atP = 0 and the values of the bulk modulus are found to be in very close agreement with experimental values for high-T _c copper oxide and their nonsuperconducting parent compounds. It is also found that the quantityAU/U( V ₀ ) of these compounds increases with increasing hydrostatic pressure.     

Perceptual and conceptual memory processes in global amnesia.

To determine whether global amnesia reflects a selective deficit in conceptual processing, amnesic and control Ss performed 4 memory tasks that varied processing and retrieval requirements. A study-phase modality (auditory/visual) manipulation validated the nature of processing (perceptual and conceptual) engaged by each task. Amnesic patients were impaired on perceptual and conceptual explicit memory tasks (word-fragment and word-associate cued recall) and were intact on perceptual and conceptual implicit memory tasks (word-fragment completion and word association). These results are consistent with the view that limbic-diencephalic structures damaged in amnesia mediate, in part, processes typically engaged during explicit retrieval. The results are inconsistent, however, with the characterization of that deficit as being one of conceptual processing per se. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Sliding wear response of a zinc-based alloy compared to a copper-based alloy

In the present investigation, an attempt has been made to study the wear response of a zinc-based alloy at different sliding speeds and pressures. The wear behavior of the zinc-based alloy has been compared to that of a conventionally used copper-based alloy against an EN24 steel disc. Operative wear mechanisms have also been discussed through the examination of wear surfaces, subsurface regions, and debris particles. The results obtained revealed that the wear response of the zinc-based alloy is much better than the conventionally used copper-based alloy at all the speeds; the latter suffered from “material chipping off,” leading to its higher wear rates. The wear characteristics of the specimens have been explained on the basis of their specific microstructural features.     

Facial expressions of emotions and schizophrenia: a review

It is generally agreed that schizophrenia patients show a markedly reduced ability to perceive and express facial emotions. Previous studies have shown, however, that such deficits are emotion-specific in schizophrenia and not generalized. Three kinds of studies were examined: decoding studies dealing with schizophrenia patients' ability to perceive universally recognized facial expressions of emotions, encoding studies dealing with schizophrenia patients' ability to express certain facial emotions, and studies of subjective reactions of patients' sensitivity toward universally recognized facial expressions of emotions. A review of these studies shows that schizophrenia patients, despite a general impairment of perception or expression of facial emotions, are highly sensitive to certain negative emotions of fear and anger. These observations are discussed in the light of hemispheric theory, which accounts for a generalized performance deficit, and social-cognitive theory, which accounts for an emotion-specific deficit in schizophrenia.