An integrated scheme for process planning and scheduling in FMS

Process planning and scheduling are the two important manufacturing functions involved in any shop floor activities. As functional integration is essential to realize the benefits of computer integrated manufacturing, a scheme for integration of process planning and scheduling has been introduced in this paper. The proposed scheme can be implemented in a company with existing process planning and scheduling departments when multiple process plans remain available on the shop floor. It consists of two main modules, introduced in detail in this paper. They are process plan selection module and scheduling module.     

A two-stage algorithm for ground filtering of airborne laser scanning data

ABSTRACT

A two-stage algorithm is proposed in this article for ground filtering of airborne laser scanning (ALS) data. Input ALS data are initially preprocessed for outliers removal. The first stage removes the non-ground objects from preprocessed ALS data based on the geometrical reasoning, which is applied over piecewise local neighbourhoods around selected points. The second stage retrieved the ground points falsely recognized as non-ground in the first stage using geometrical similarity of ground points in their surroundings. The proposed algorithm was tested and validated comprehensively using complex and heterogeneous landscapes of selected 10 ALS data sets and additional 15 International Society of Photogrammetry and Remote Sensing data samples. The ground points were filtered out in these data sets and data samples at average total error and kappa coefficient of 3.66% and 89.15%, respectively. The proposed algorithm performs satisfactorily in the complex terrain cases such as mixed vegetation and houses on sloping terrain, low vegetation, complex objects, low and small objects, scene border, and discontinuity. The proposed algorithm is straightforward and, consequently, computationally efficient. Thus, it has potential for wider use in industry.     

A review on manufacturing flexibility

Flexibility has become one of the most useful and necessary tool in today’s competitive markets. Manufacturing flexibility is widely recognised as a critical component to achieving a competitive advantage in the market place. It is one of the most sought after properties for manufacturing enterprises and has aroused considerable interest among researchers and professionals. This paper presents a review of various issues related with manufacturing flexibility specifically concept, need, dimensions, measurement, relationship among various dimensions, implementation aspect in a company and management of manufacturing flexibility and its aim to contribute to the conceptual systemisation of the material.     

Ligand concentration and reaction time controlled successive substitution of chloro and η6-benzene of di-μ-chlorobis{η6-benzene)dichlororuthenium(II)} with selenated Schiff base: Formation of half sandwich Ru(II) complex highly active catalyst for oxidation of alcohols

Schiff base (L) synthesized by reacting 2-methylthiobenzeldehyde with 2-(phenylseleno)ethylamine on reaction with di-μ-chlorobis{η⁶-benzene)dichloro-ruthenium(II)}(a) forms two type of species: (i) [Ru(L)₂][PF₆]₂ (1) [L:a = 4:1 and reaction time ～8 h] and (ii) [Ru(η⁶-C₆H₆)(L)][PF₆]₂ (2) [L:a = 2:1 and reaction time ～1 h]. This is first example in which chloro as well benzene ring both are successively substituted by controlling metal:ligand ratio and duration of reaction. The geometry around Ru in complex 1 is distorted octahedral. The 2 has a pseudo-octahedral half sandwich “piano-stool” disposition of ligands around Ru. The Ru–Se distances are 2.4683(10)–2.5082(7) ?. The proton and carbon-13 NMR spectra of L and its both complexes 1 and 2 authenticate them. The 2 shows high catalytic activity for oxidation of primary and secondary alcohols both (TON upto 9.6 × 10⁴; TOF upto 4.80 × 10⁴ h^?1).     

ANALYSIS OF TRANSIENT TEMPERATURE DISTRIBUTIONS IN A PERFUSED MEDIUM DUE TO A SPHERICAL HEAT SOURCE WITH APPLICATION TO HEAT TRANSFER IN TUMORS: HOMOGENEOUS AND INFINITE MEDIUM

The role of conduction and convection in transferring heat through a perfused medium is quantified by analyzing the transient temperature field within and around a spherical heat source embedded in the medium, using the bio-heat transfer equation. Analytical expressions for transient temperature distributions are obtained in terms of the following dimensionless variables: ξ, the relative position; τ, the Fourier number; β²;, the Peclet number, and ratios of thermal conductivities and difFusivities. The perfused medium is assumed to be infinite, isotropic and homogeneous. Frequency response of the probe to sinusoidal power input is also analyzed. The analytical expressions obtained are used to estimate heat transfer characteristics of tumors from in vivo data describing blood flow and temperature distributions around a spherical probe.     

Modelling of hybrid energy system—Part I: Problem formulation and model development

A well designed hybrid energy system can be cost effective, has a high reliability and can improve the quality of life in remote rural areas. The economic constraints can be met, if these systems are fundamentally well designed, use appropriate technology and make use effective dispatch control techniques. The first paper of this tri-series paper, presents the analysis and design of a mixed integer linear mathematical programming model (time series) to determine the optimal operation and cost optimization for a hybrid energy generation system consisting of a photovoltaic array, biomass (fuelwood), biogas, small/micro-hydro, a battery bank and a fossil fuel generator. The optimization is aimed at minimizing the cost function based on demand and potential constraints. Further, mathematical models of all other components of hybrid energy system are also developed. This is the generation mix of the remote rural of India; it may be applied to other rural areas also.     

Low-Bit-Rate VQ: A Projection Based Approach

In this paper, we present an image decompression scheme that emphasizes visual perception rather than objective signal integrity between the orginal and the reconstructed images. The decoding scheme is developed in the context of vector quantization (VQ). The technique includes a projection based image recovery algorithm as part of the decoding process. The quantized blocks are classified into edge and shade blocks. The edge blocks are filtered using optimized templates while the shade blocks are left unaltered. The method can be considered as a constrained smoothing of edges, which does not cause any degradation to the shade (background) regions in the decoded image. The result is a reconstruction that is subjectively better than a simple look-up table decoding.     

Organorhenium(Ⅶ) oxides

Methyltrioxorhenium (MTO) and its derivatives were utilized as catalysts for a broad variety of organic reactions after the discovery of an easy synthetic access way to this class of compounds. Among the numerous characterization techniques, 17O-NMR spectroscopy and vibrational spectroscopy were exemplary discussed. The immobilization of MTO and its derivatives is of significant current interest as is the synthesis of chiral derivatives.     

DYNAMIC MODEL OF CHOPPER FED DC SEPARATELY EXCITED MOTOR

ABSTRACT

This paper describes the transient response of a chopper fed dc separately excited motor using time ratio control. An approximate second order model for predicting the transient behaviour of the motor is developed using perturbation technique. The transient response for small and sudden variations of duty interval and load torque is deduced during discontinuous and continuous current mode operations. The effect of external inductance on the performance of motor in the armature circuit has also been investigated. The results are compared with those obtained from a digital computer by numerically solving the simultaneous differential equations valid for different intervals of chopper cycle and also with the first order model. It is shown that the second order model is more accurate than the first order model and much simpler and efficient than the numerical approach. The theoretical results obtained are also verified with an experimental set up. Experimental results closely agree with theoretical predictions.