Machine grouping problem in cellular manufacturing systems— an integer programming approach

In this paper a methodology is proposed to group the machines in cellular manufacturing systems based on the tooling requirements of the parts, toolings available on the machines and the processing times. Two 0-1 integer programming formulations are proposed. These formulations assume that the part families are known. The first formulation groups the machines based on the compatibility of parts with machines. The second formulation groups the machines in order to minimise the cost of allocating the machines and the cost of intercell movement. These formulations take into account the limitations on the number of machines in a group and the number of machines available of a particular type. The application of these formulations is illustrated using an example.     

Assessment of patentability by means of semantic patent analysis – A mathematical-logical approach

To obtain patent protection, a patent must fulfill statutory patentability requirements examined by a patent office. Such examinations are mostly performed manually and are quite time-consuming. Therefore, we suggest a computer-based process for the assessment of patentability by means of a mathematical-logical approach comparing patents with semantic structures. In order to make such an assessment, we compare the feature combinations of patent claims with the pertinent prior art. For proof of concept, the process has been tested successfully on an US-application claiming a method for raising a crane boom which can be categorized as non-patentable with regard to the requirement of non-obviousness. The result is consistent with that of a USPTO patent examiner, which underpins that at least under certain conditions not only patent examiners but also applicants and third parties can assess the chance and scope of protection for claimed inventions and patent applications with regard to patentability by our process.     

Testing the proficiency of analytical laboratories by means of inter-laboratory comparison tests – an important element in assurance of the uniformity of measurements

The role of proficiency testing of laboratories through inter-laboratory comparison tests in an effort to assure the uniformity of measurements is considered.     

Heating of metals at a free surface by laser irradiation—an electron kinetic theory approach

Application of Fourier theory to heat conduction due to laser irradiation at high power intensities (i.e. 10¹⁰ w/m²) gives errors of the order of 30 percent at the upper end of the temperature rise time. This is caused by the assumptions made in the Fourier theory, since the heat flux through a given plane depends on the electron energy distribution through the material. The scale of distance required to examine the problem, the material can no longer be considered as being homogenous continuum and when the power intensities of interest are concerned, the higher order terms in the heat transfer equation becomes important. Therefore, the problem requires to be examined in the quantum field. Application of electron kinetic theory to the problem enhance the solution within an accuracy greater than 90 percent. The present theory introduces a new model for the conduction mechanism.     

The energetics of helium and hydrogen atoms in β-SiC: an ab initio approach

Silicon carbide is a prime candidate for plasma-facing materials in future fusion reactors. The formation energies of various interstitial configurations of helium and hydrogen atoms in β-SiC were estimated based on density functional theory. Special consideration was given to the helium and hydrogen interstitials as the bubble seeds in β-SiC. From an energetic point of view, only one helium atom could position itself into the tetrahedral sites. However, up to three hydrogen atoms could easily position themselves into the tetrahedral sites by forming a stable H₂ molecule or a 3H-trimer that was newly identified in this study. Based on the different behaviors of helium and hydrogen, an explanation is proposed for the experimental observations of bubble formation in irradiated β-SiC.     

Minimizing stochastic moiré in frequency-modulated halftones by means of green-noise masks

In color halftoning, moiré is the low-frequency spatial artifact generated by the interference of superimposed primary color dot screens that adds an unwanted artificial texture to the printed image. When these overlapping dot screens are irregular, as in the case of stochastic dot screens, this interference pattern follows a random spatial distribution resulting in 'stochastic" moiré. This stochastic moiré is at its most visible when the overlapping dither patterns have the same relative spacing between dots. We study the occurrence of stochastic moiré in green-noise halftones where dither patterns are composed of clusters of varying sizes and where the visibility of stochastic moiré6 can be reduced by varying the coarseness of dither patterns between the component cyan, magenta, yellow, and black colors.     

A study of the surface of carbon fiber by means of X-ray photoelectron spectroscopy—III

This paper reports a study of the surface composition of carbon fibers treated by various methods by means of X-ray photoelectron spectroscopy (SPS). C_1S X-ray photoelectron spectra showed that after the surface treatment of carbon fibers, the carbon atoms in the hydrocarbon were changed into

etc. oxygen-containing groups, that is, the results of surface oxidation and concentration increased with time but finally reached a constant level. Comparing experimental results for the treatments used, we found that all of these methods resulted in concentrations of oxygen groups on the surface in the order:

.Evidence was found for the formation of lactone groups

during treatment in an oxygen or nitrogen plasma, but not during treatment by nitric acid or anodic oxidation.     

Errata to “The effect of an axial temperature gradient on the steady motion of a large droplet in a tube” by S. K. Wilson

Errata to The effect of an axial temperature gradient on the steady motion of a large droplet in a tube by S. K. Wilson J. Eng. Maths 29 (1995) 205–217     

Measurements of the mechanical stress in mild steel by means of rotation of magnetic field strength —part 3: practical applications

An annealed disc of mild steel, 400 mm diameter and 12.7 mm thick, was compressed at the ends of a diameter. The isochromatic and isoclinic stress contours were measured magnetically using equipment called the Rotation Rig. The isochromatics agreed with the theoretical stress contours to within 20% and the agreement between isoclinics was ± 5°. Results are also given for the residual stresses around a weld in a steel plate, but these are not confirmed by an alternative method.     

Diffraction of elastic waves by an elliptic crack—II

A recently developed integral equation technique is used to obtain a low frequency solution for the diffraction of a plane compressional or shear wave by an elliptic crack embedded in an elastic medium. The mixed boundary value problem is reduced to a coupled system of integro-differential equations. A formal power series solution for the coupled system of integro-differential equations is developed. Attention is focussed on the farfield scattered amplitudes and the dynamic stress intensity factor. The limiting values when the ellipse degenerates into a circle agree with those of a circular crack.     

Development of papain containing pellets produced by extrusion–spheronization: an operational stage approach

The performance of the standardized extrusion–spheronization technique, operational conditions, formulation parameters and storage of the final product over the bioactivity of papain containing pellets has been evaluated to obtain an insight into the potential of the technique for the manufacture of solid protein formulations. The pellets produced were assayed in terms of biological activity – monitored at each operational stage using N-benzoyl-dl-arginine ρ-nitroanilide as a substrate, and according to the physical properties – evaluated by means of size distribution, apparent density and friability. The produced pellets presented adequate physical and mechanical properties. Monitoring biological activity at each production stage revealed that the most critical steps corresponded to drying and storage, with bioactivity decay ranging from 5 to 30% and 5 to 20% for each process. Dry mixing and extrusion did not hold any influence over papain activity, while wet massing decreased the bioactivity by approximately 0–5% and the spheronization 0–2%. The results varied as a function of the experimental conditions and formulation components. In conclusion, the extrusion--spheronization technique was suitable to produce solid multiparticulate dosage forms for papain, considering the possibility to originate pellets with relatively low bioactivity decay. However, weak points of the technique corresponded to the wet massing and drying stages as well as storage.     

The substrate problem in X-ray diffraction of boron-rich amorphous FeB alloys

Energy-dispersive X-ray diffraction spectra of boron-rich amorphous FeB alloys are presented. Special attention is paid to the preparation of the samples in a sputtering apparatus specially designed to give very pure materials. A solution is given to the “substrate problem”. The amorphous films are sputtered onto thin polycarbobate foils 2 μm thick fixed to a copper backing by means of SIRA adhesive wax. It is shown that the data evaluation is greatly simplified when the polycarbonate is directed towards the incident X-ray beam during the measurements.     

Cobalt rich phase formation in metastable Cu–Co alloys by means of melt spinning

Abstract

Metastable CO_xCU_100?x alloys with extended cobalt solubility (5≤x≤20), which can not be obtained by equilibrium methods, were prepared by melt spinning. The separation of the cobalt rich phase upon heating was monitored by X-ray diffraction and calorimetric measurements. The volume fraction of cobalt rich particles can not be determined using X-ray diffraction if the cobalt rich particle size is below a critical value. The separation of the cobalt rich phase seems to be a three step process including nucleation, growth, and coarsening. The non-isothermal kinetics of nucleation and growth of the cobalt rich phase were analysed in terms of a modified Kissinger model. The heat release during phase separation is closely related to the amount of cobalt dissolved in the copper matrix.

MST/3258     

The 'stage’ model of growth of small firms—an alternative hypothesis

Amongst the types of problem faced by production managers in a wide variety of Canadian industries, those concerned with growth and change are encountered frequently and are especially severe in small firms. This paper proposes and tests the hypothesis that as small companies grow they pass through alternating phases of good and poor performance. During the latter phases there is a high probability of failure brought about by common problems in a homogeneous group of small companies in an industry. The analysis of data so far supports the hypothesis in commercial printing firms of up to 70 employees, but requires modification for larger companies,     

Effect of gas introduction position on substrate etching by means of Ar-dominated graphite-cathodic-arc plasma beam in μT-FAD

Substrate etching by means of Ar-mixed graphite-cathodic-arc plasma beam was investigated in a newly-developed compact-type μT-FAD. The surface level and roughness change were measured as a function of the Ar gas flow rate, when Ar gas was introduced into the arc generation zone and in the vicinity of the substrate. When Ar gas was introduced to the arc generation zone, the etching rate was lower but the surface was relatively not roughened. When Ar gas was introduced in the vicinity of the substrate, the etching rate was higher but the surface was roughened. At the same gas flow rate (and pressure), the substrate was etched more than three times faster when Ar gas was introduced into the arc generation zone than to the vicinity of the substrate. After measuring the discharge and plasma conditions, the results were considered to be caused by the difference in the amount of plasma transported to the substrate.     

The role of periodic solutions in the Falkner-Skan problem for λ>0

Summary The Falkner-Skan equation and those being periodic. In both cases, numerical evidence is given for a rich structure of multiple solutions. Branching occurs for =1,2,3,.... All solutions can be characterized by means of a special subset of periodic solutions.     

The approximate solutions to source inverse problem of 1-D convection–diffusion equation by LS-SVM

This article deals with the determination of the source in 1-D convection–diffusion problem. A method which based on the least squares support vector machines is proposed. The approximate solutions consist of two parts. The first part is a known function that satisfies the initial/boundary conditions. The other part is the combination of Gauss Kernel functions with regression coefficients, which is not affected from the initial/boundary conditions. According to the principle of least squares support vector machines regression, the problem can be transformed into a quadratic programming. The method has been tested on four examples and has yielded accurate results.     

The Status Quo of China''''s Industrial Engineering: Retrospect and Prospect——The 7th Academicians''''Saloon held in Shanghai by Shanghai Academicians''''Center

The 7th Academicians' Saloon, with the theme of "The Status Quo of China's IndustrialEngineering--Retrospect and Prospect" was held in the Sinan Buildng, Shanghai Science Hall onMareh 7, 2003. More than 30 people attended this saloon, including academicians, scholare, specialistsand entrepreneurs from the academic circles and business ciroles in Shanghai. Members of the editorialboard & editorial office of IE&M were invited to the saloon. The academicians, specialists, scholars andentrepreneurs, with the introduction of their own experiences and understanding, have discussed and