On the Use of A Vehicle Routing Algorithm for the Parallel Processor Problem with Sequence Dependent Changeover Costs

We consider the problem of sequencing a set of changeover dependent jobs in a parallel processor shop subject to a workload restriction where the objective is to achieve minimum total changeover cost. A heuristic algorithm, developed previously to treat the vehicle delivery model, is used on the problem. Suitable computational experience with the algorithm is provided the results of which would support its application to problems of realistic size.     

Two manpower location aspects of energy resource development: Case of the Wyoming uranium industry

Several strip-mine mineral industries in the West--particularly coal, uranium, and oil shale--are currently the center of concern to energy and rural development policy makers. In addition to numerous environmental and social ramifications of development of these industries, large numbers of jobs may be generated in what are presently sparsely populated rural areas. This raises questions regarding places of origin of employees and creation of new mining towns versus location of employees in existing towns. In order to gain insights and direction for future developments, the existing Wyoming uranium industry work force is examined in this study with respect to 1) the locational origins of employees and 2) employee commuting patterns. Manpower location considerations in rural development are conceptualized in the first portion of the paper. Work force patterns in three uranium areas of Wyoming are then analyzed and compared. Implications of the empirical findings for manpower and development policies are explored in the concluding section of the paper. Manpower training and transportation policies are addressed.Wyoming Agricultural Experiment Station Journal Article No. JA 602. This paper results from research carried out under Wyoming Agricultural Experiment Station Proiect Wyo. 63–71 and Western Regional Research Project W-113, entitled Improvement of Employment Opportunities and Earnings for Disadvantaged People in Non-metropolitan Areas. The paper has benefited from the comments of several individuals at the University of Wyoming; a number of comments made by John Leyes were particularly helpful.     

Lipids of six cultivated barley (Hordeum vulgare L.) varieties

The lipids of representative varieties of 2-row spring, 6-row spring, and 6-row winter-type barleys were studied. Total barley lipids were classified by silicic acid gel column chromatography and separated by thin layer chromatography, and the fatty acid composition was determined by gas liquid chromatography. Total lipid content of the 6 barley varieties ranged from 3.12%–3.56% (dry wt basis). The average values for neutral lipids, glycolipids, and phospholipids were 71, 9, and 20%, respectively. The fatty acid composition of barley was rather typical of plant tissue. The neutral lipids and glycolipids from all the varieties contained a higher percent of linoleic and linolenic (C 18∶2 and C 18∶3) acids than the phospholipid fraction. South Dakota Experiment Station Paper 1248.     

Tomorrow's mass rapid transit?available today!

Similarity exists between moving large masses of people and the process industry. Both have fixed inputs, fixed outputs, predictable patterns, variables that can be measured, and corrections that can be made. Both entities respond to the principle of closed-loop regulation. From the experience gained in the San Francisco Bay Area Rapid Transit District (BARTD), a planned approach to coordinated and automated mass transportation systems is entirely feasible. Electronic controls are a major factor in providing an economic solution to the problem.     

Imperfections in laser clading with powder and wire fillers

Laser cladding has been increasing in laser job shops both for component repair and manufacture. The process is quite mature nowadays, from a scientific approach, but companies need manufacturing guidelines and procedures to minimise the occurrence of defects and improve service quality and productivity. Typical imperfections occurring in laser clads can be divided into two major groups: shape and microstructural defects. The first group includes the contact angle of the clad track with the substrate surface and the total height of the clad including penetration. In the second group are considered lack of fusion, porosity and cracks. It is not clear to which extent the use of powder or wire as filler materials influence defect formation, though it is well known that these are mostly related to material properties and operational procedures. This paper presents the work done in laser cladding using filler wire and powder in real productive environment in job shop cases on different substrates: AISI 316 stainless steel, H13 and P20 tool steels. An overview of the defects that are more prone to appear in these materials is presented and strategies to minimise their occurrence proposed.     

Performance enhancement of mSCTP for vertical handover across heterogeneous wireless networks

In the mobile Stream Control Transmission Protocol (mSCTP) for vertical handover, a mobile user may suffer from performance degradation due to the problems of packet reordering and retransmission timeout and due to the packet loss during handover. To solve these problems, we propose a new scheme of handover retransmission for mSCTP handover, in which the correspondent node retransmits the outstanding data packets to the mobile node over the new primary path. From simulation results, it is shown that the proposed scheme can avoid the packet reordering and retransmission timeout problems during handover. Moreover, we can see that the proposed scheme can significantly improve throughput of mSCTP handover, compared with the existing schemes. Copyright © 2009 John Wiley & Sons, Ltd.     

Identification of Nucleation Center Sites in Thermally Annealed Hydrogenated Amorphous Silicon

Utilizing the concepts of a critical crystallite size and local film inhomogeneity, it is shown that nucleation in thermally annealed hydrogenated amorphous silicon occurs in the more well ordered spatial regions in the network, which are defined by the initial inhomogeneous H distributions in the as‐grown films. Although the film H evolves very early during annealing, the local film order is largely retained in the still amorphous films even after the vast majority of the H is evolved, and the more well ordered regions which are the nucleation center sites for crystallization are those spatial regions which do not initially contain clustered H, as probed by H NMR spectroscopy. The sizes of these better ordered regions relative to a critical crystallite size determine the film incubation times (the time before the onset of crystallization). Changes in film short range order upon H evolution, and the presence of microvoid type structures in the as grown films play no role in the crystallization process. While the creation of dangling bonds upon H evolution may play a role in the actual phase transformation itself, the film defect densities measured just prior to the onset of crystallization exhibit no trends which can be correlated with the film incubation times.     

Influence of Mg Addition on the Catalytic Activity of Alumina Supported Ag for C3H6-SCR of NO

The influence of different magnesium (Mg) weight percentages (1, 2.5, 5, 7.5 and 10) over silver (3 wt%) impregnated alumina (SA) catalyst was investigated for the reduction of NO by C₃H₆. Mg doped SA catalysts were prepared by conventional impregnation method and characterized by XRD, BET-SA, ICP-MS, XPS, SEM, UV-DRS, H₂-TPR and O₂-TPD. The existence of MgO and MgAl₂O₄ phases on Mg doped SA catalysts were observed from XRD and XPS analyses. Existence of high percentage MgAl₂O₄ phase on 5% Mg doped SA catalyst (Mg (5) SA) enhances the dispersion and stabilization of silver phases (Ag₂O). Mg (5) SA catalyst shows a 51% of high selectivity (NO to N₂) in presence of SO₂ (80 ppm) at low temperatures (350 °C) and maintained high selectivity’s with a wide temperature window (350–500 °C). An optimal high surface availability of Ag⁰ and Ag⁺ species were observed from XPS analysis over Mg (5) SA catalyst. H₂-TPR analysis shows high temperature reduction peak over Mg (5) SA compared to SA catalyst. XPS analysis confirms the high percent availability of MgAl₂O₄ species over Mg (5) SA catalyst. DRIFTS study reveals the molecular evidences for the evolution of enolic species during NO reduction over the highly active Mg (5) SA catalyst at low temperatures. It also confirms further transformation of enolic species into –NCO species with NO + O₂ and finally into N₂ and CO₂.     

A high resolution XPS study of sidewall functionalized MWCNTs by fluorination

Carbon nanotubes must be modified to magnify their application. Understanding the chemistry of carbon nanotubes is a crucial step towards their ultimate practical use. In this study, multi-walled carbon nanotubes (MWCNTs) were fluorinated at several different conditions. The change in the atomic structures of fluorinated MWCNTs was investigated using X-ray photoelectron spectroscopy (XPS). All core level spectra of MWCNTs were deconvoluted to several Pseudo-Voigt functions (sum of Gaussian–Lorentzian functions). The amount of doped fluorine increased with increasing doping fluorine partial pressure, and the fluorine atoms were covalently attached to the side-wall of the MWCNTs. However, the increasing rate of F1s component ratio became dull at 70%, as compared with ratios below 70%. This suggests that fluorine contents during the fluorination of carbon materials can be managed by controlling the fluorine mixing ratio.     

Palladium‐Catalyzed Decarboxylative sp‐sp2 Cross‐Coupling Reactions of Aryl and Vinyl Halides and Triflates with α,β‐Ynoic Acids using Silver Oxide

Palladium‐catalyzed decarboxylative sp‐sp² cross‐coupling reactions of aryl and vinyl halides and triflates with α,β‐ynoic acids using silver oxide have been developed. A variety of α,β‐ynoic acids were readily decarboxylated in the presence of silver oxide and then, generated in situ, silver acetylides were coupled with electrophiles in the presence of a palladium(0) catalyst under neutral conditions, producing either symmetrical or unsymmetrical diarylacetylenes, arylalkylacetylenes and arylvinylacetylenes in good to excellent yields.