Generalized orderings of excess lifetimes of renewal processes

Several concepts of generalized orderings and generalized ageing classes have been considered in the literature (see Fagiuoli and Pellerey, 1993, Nav Res Logist 40: 829–842). They have been used in reliability, economics and actuarial sciences. These generalized notions provide a knowledge of the intrinsic structure of the ageing and ordering properties of random variables and have become an important tool in applied probability. In this paper, we provide new results about generalized orderings of excess lifetimes at different times of a renewal process when the underlying distribution belongs to some generalized ageing class. We also derive some interpretations and give some discussions of these results.     

Pressure drop and cavitation investigations on static helical-grooved square, triangular and curved cavity liquid labyrinth seals

Sodium cooled Fast Breeder Reactors (FBR) form the second stage of India's Nuclear power programme. Through a narrow annular space in the grid plate assembly of a prototype FBR, a very low leakage flow of liquid metal sodium should pass, experiencing a stipulated high pressure drop, and without much cavitation. To achieve this, a suitable labyrinth seal is required to be developed for use in the annulus. Water is employed as the model testing liquid which is estimated to experience a pressure drop ratio of 10.5 at the rated leakage flow. Previously studied circular or sinusoidal-grooved square, triangular or curved cavity labyrinth seals were unable to meet this value. In the present work, Computational Fluid Dynamics (CFD) analyses are carried out on Helical-grooved Square cavity Labyrinth Seals (HSLS), using commercial code Fluent. It is found that the geometrical configuration of the grooves plays a major role on the pressure drop. Experimental results reveal close agreement with CFD predictions. An optimal configuration of this square cavity seal is identified by applying genetic algorithm (GA) using commercial packages. It meets just about 24% of the targeted value. Later, using parametric CFD analyses, a Helical-grooved Triangular cavity Labyrinth Seal (HTLS) and different Helical-grooved Curved cavity Labyrinth Seals (HCLS) are analysed. The most favourable profile is tested and found to reach the required pressure drop. CFD cavitation analyses predict the intensity of cavitation in these seals to be below prohibitive levels.     

Single pole compact narrow band pass filter using periodic ground defects

In this paper a compact narrow band pass filter has been designed. An H-shape section of microstrip is used to get the smaller band width. The parallel lines are connected to the H section. The periodic slots are made on the ground plane of the microstrip. These defects cause the circuit more compact. The filter has been designed for center frequency 4 GHz and fractional band width 3%. The design methodology has been clearly explained. To verify the proposed technique, a filter has been fabricated and tested. Amoderate matching of the results between the measured and simulated results has been observed due to some imperfection in fabrication.     

Twin-bus-controller protocol for fibre optic networks

A new Data Link Layer protocol, named the Twin-Bus-Controller (TBC) protocol, is proposed for a fibre optic network with unidirectional bus topology. The TBC protocol operates on a contention-based, time-division multiplexing scheme, and is managed by two centralized bus controllers. These controllers, which also function as network managers cooperate with each other to control and coordinate the activities on the twin bus. The IBC protocol has the capability to perform at a very high network utilization, and uses simple hardware at all stations except the two bus controllers. This arrangement provides a relatively inexpensive means to accommodate a large number of stations. Heterogeneous data consisting of real-time sensor and control signals, voice and video data, and non-real-time data such as those due to accounting and administration, can be simultaneously handled by the TBC protocol. The TBC protocol maintains global queues for all different types of data, and each class of data has a bounded delay. Furthermore, any new type of data can be added easily to the network without shutting it down or affecting those stations that are unrelated to the new data. A finite-state-machine model has been used to describe the TBC protocol. Performance of the TBC protocol has been evaluated by statistical analysis as well as via simulation for multiple classes of data traffic. Performance of the TBC protocol has been compared with that of Buzznet and Fasnet. The TBC protocol can be directly applied to diverse computer communication systems, e.g. office, manufacturing, and banking environments.     

Solar cells consisting of phenazine dyes in polymer matrix

We have constructed p−n heterojunction solar sandwich cells with phenazine dyes in a thin film of polyvinyl alcohol placed between a conducting glass coated with indium oxide and a platinum foil. The current-voltage relations of the cells have been measured in the dark and light under both forward and reverse biases.     

Wall-to-bed heat transfer characteristics of spout-fluid beds

Wall-to-bed heat transfer characteristics have been investigated in a rectangular spout-fluid (S–F) bed segment column (20 cm length, 5 cm width and 50 cm height) utilizing glass beads (D_p = 0.254, 0.388 and 0.461 mm) and air as fluid. Results indicate that h values in the S–F bed increase with increasing air mass velocity and particle diameter, and decrease with increasing bed height. Under identical flow conditions h values in the S–F bed were about 30% more than for the corresponding fluidized bed.     

Innovative Utilization of Improved n-doped μc-SiOx:H Films to Amplify the Performance of Micromorph Solar Cells

Silicon - Due to in-situ deposition process doped SiOx material attracts the PV community as intermediate reflecting layer (IRL) for the less hazardous deposition process. Previously we have been...     

Performance management of integrated manufacturing system networks

Performance management of communication networks is critical for speed, reliability, and flexibility of information exchange between different components, subsystems, and sectors (e.g., factory, engineering design, and administration) of production process organizations in the environment of Computer Integrated Manufacturing (CIM). The objective is to improve the efficiency in handling various types of messages, e.g., control signals, sensor data and production orders, by on-line adjustment of the parameters of the network protocol. This paper presents conceptual design, development, and implementation of a performance management procedure for CIM applications. The performance management algorithm is formulated using the concepts of: (i) perturbation analysis of discrete event dynamic systems; (ii) stochastic approximation; and (iii) learning automata. The performance management procedure has been tested via emulation on a network testbed that is based on the Manufacturing Automation Protocol (MAP). The conceptual design presented in this paper offers a step forward to bridging the gap between management standards and users' demands for efficient network operations since most standards such as ISO and IEEE address only the architecture, services, and interfaces for network management. The proposed concept for performance management can also be used as a general framework to assist design, operation, and management of flexible manufacturing systems.