Friction and forced convective heat transfer in a sintered porous channel with obstacle blocks

This work experimentally studies the flow characteristics and forced convective heat transfer in a sintered porous channel that filled with sintered copper beads of three average diameters ( 0.830, and 1.163 mm). The pressure drop and the local temperature measurements can be applied to figure out the distributions of the friction coefficient and the heat transfer coefficient. Three sintered porous channels differ in the arrangement of obstacle blocks. Model A has no obstacle. Models B and C have five obstacle blocks facing down and up, respectively, in a sintered porous channel. The range of experimental parameters, porosity, heat flux, and effect of forced convection are 0.370 ≤ ɛ ≤ 0.385, q=0.228, 0.872, 1.862 W/cm², and 200 ≤ Re _d ≤ 800. The permeability and inertia coefficient of each of the three sintered porous channels are analyzed. The results for Model A agree with those obtained by previous investigations in C _f distribution. The heat transfer of Model C exceeds that of Model A by approximately 20%. Finally, a series of empirical correlation equations were obtained for practical applications and engineering problems.     

Synthesis and study of N,N‐disubstituted 4‐[(4‐aminophenyl)diazenyl]benzylidene‐4′‐alkylanilines

A series of N,N‐disubstituted‐4‐[(4‐aminophenyl)diazenyl]benzylidene‐4′‐alkylanilines (azo dyes) were synthesized from the reaction of the corresponding benzaldehyde with alkylanilines. These azo dyes exhibit nematic and SmC phases on heating. Their order parameter, photo‐stability and miscibility were studied by investigation of a representative sample.     

Fine Substituent Effects in Sandwich Complexes: A Threshold Ionization Study of Monosubstituted Chromium Bisarene Compounds

Mass‐analyzed threshold ionization spectra of jet‐cooled [(η⁶‐PhMe)(η⁶‐PhH)Cr] and [(η⁶‐Ph₂)(η⁶‐PhH)Cr] reveal with unprecedented accuracy the effects of methyl and phenyl groups on the electronic structure of bis(η⁶‐benzene)chromium. These “pure” substituent effects allow quantitative experimental determination of the ionization energy changes caused by the mutual substituent influence in bisarene systems. Two types of such influence have been revealed for the first time in bis(η⁶‐toluene)chromium.     

Study on tribological behaviors of short glass fiber and polytetrafluoroethylene reinforced polycarbonate composites via a d‐optimal mixture design

This study analyzed variations of tribological behaviors that depend on the injection molding techniques during the blending of short glass fiber (SGF) and polytetrafluoroethylene (PTFE) reinforced polycarbonate (PC) composites. The proposed planning of blending experiments is to use a D‐optimal mixture design (DMD). The tribological behaviors of friction coefficient and wear mass loss were selected for discussion. Nine experimental runs, based on a DMD method, utilized to train the back‐propagation neural network (BPNN) and then the simulated annealing algorithm (SAA) approach is applied to search for an optimal mixture ratio setting. In addition, the result of BPNN integrating SAA was also compared with response surface methodology (RSM) approach. The results of confirmation experiment show that DMD, RSM, and BPNN integrating SAA method are effective tools for the optimization of reinforced process. Furthermore, the scanning electron microscope (SEM) images show that the abundant debris are peeled off from the matrix materials and predominant delamination mechanisms and plastic deformation are shown on the worn surface after tribological behavior tests. Copyright © 2010 John Wiley & Sons, Ltd.     

The minimum norm method for the determination of the charge density from elastic electron scattering data

Unphysical behavior in the QR algorithm based least squares determination of the expansion coefficients of the charge density obtained from limited information about the charge form factor occurs when the spread of the singular values in the matrix relating these quantities becomes too large. Setting the smallest singular values equal to zero in the singular value decomposition used in the minimum norm method yields a much more reasonable determination of the charge density. Increasing the size of the basis without increasing the range of the prior information about the charge form factor leads to ambiguities in the determination of the charge density. Numerical results in an analytic model are presented.     

Identification of interrelationship of key customers’ needs based on structural model for services/capabilities provided by a Semiconductor-Intellectual-Property Mall

The semiconductor industry is shifting towards innovation and acquisition of intellectual property. Semiconductor-Intellectual-Property (SIP) design, a new industry, is also rapidly growing. This challenges both providers and users to develop infrastructure and standard interfaces. Establishing an SIP Mall to provide a full array of SIP business services is a new concept used to promote growth of the SIP industry. Many foundries and governments have been involved in setting up SIP Malls; however, the major services needed for an SIP Mall to attract SIP providers and SIP users must still be clarified. In this paper, the DEMATEL (DEcision MAking Trial and Evaluation Laboratory) method was used to discover and illustrate the key services needed to attract SIP users and SIP providers to an SIP Mall. Research enabled the derivation of the interrelated services and the structural interrelationship between them using the DEMATEL method. Overall, four key services were found to be vital for an SIP Mall to attract customers and to allocate resources efficiently.     

Chemical Oxidative Degradation of Acridine Orange Dye in Aqueous Solution by Fenton's Reagent

Degradation of acridine orange (AO) in aqueous solution by Fenton's reagent (Fe²⁺ and H₂O₂) was investigated. The effects of different reaction parameters such as initial AO concentration, pH value of solution, ferrous concentration, hydrogen peroxide concentration, and the presence of chloride ion on the oxidative degradation of AO were investigated. Under optimum conditions, 2 mM H₂O₂, 0.4 mM Fe²⁺ and pH 3.0, the initial 0.2 mM AO solution was reduced by 95.8% within 10 min. The primary intermediates of the degradation reaction of AO were identified. The analytical results indicated that the N‐de‐methylation degradation of AO dye took place in a stepwise manner to yield mono‐, di‐, tri‐, and tetra‐N‐de‐methylated AO species generated during the Fenton process. The probable degradation pathways were proposed and discussed.