bluuebunny/crossref_metadata_2025 huggingface dataset:
Determination of effective macropore diffusion coefficients by digital image processing
Authors: Meyerhoff Karsten , Hesse Diethard
Published: August 2005

In this contribution, a new method is proposed for determining effective macropore diffusion coefficients in porous media by digitized microphotographs of porous support materials and random walk simulations. The method introduced allows calculation of the effective diffusion coefficient as a function of the mean free path length over a wide variety of values. A versatile method for the preparation of porous substances for light microscopy is described.

The frequently applied model of an active shell, which is used to model particle/solid collisions, was found to give incorrect results in conjunction with the application of the first passage time algorithm, which was applied to save computing time in the simulation of gas diffusion. It was possible to show that more realistic results are obtained if a Knudsen layer is used to model particle/solid collisions. Furthermore, in investigating diffusion in two‐ and three‐dimensional representations of capillary tubes, it was found that results of simulations performed to calculate transport properties of fluids in porous media, based on two‐dimensional model systems, cannot in any case be transferred to the corresponding three‐dimensional systems.
Mathematical modeling and simulation studies of scale‐down fermentation systems
Authors: Özbek Belma
Published: August 2005

In this study, a scale‐down approach has been used for the simulation of the imperfect mixing on the growth processes by considering several configurations of continuous stirred tank reactor (CSTR, aerated) and plug flow tubular reactor (PFTR, not aerated). The steady‐state concentrations of biomass and enzyme in a continuous culture were calculated as a function of dilution rate using modified Monod growth kinetics. A mathematical model for each combination of two bioreactors was developed to account for growth, substrate utilization (oxygen and glucose) and enzyme synthesis and decay. The model was then used to investigate biomass production and enzyme expression in relation to the volumetric fraction Uf = VPFTR/(VCSTR + VPFTR) and the recirculation ratio R = fr/(f + fr) of the fermentation system. These two mixing parameters were found to be significant factors in the biomass and enzyme production from the fermentation system. This model was also compared with some of the existing models.
Optimization of a process for the synthesis of a sperm whale oil analogue
Authors: Bautista L. Fernando , Martínez Mercedes , Aracil José
Published: August 2005

The development and optimization of the synthesis of an analogue of sperm whale oil have been carried out. The product is an ester with characteristics similar to those of natural sperm whale oil. A central composite design was applied in the synthesis of this fine chemical. The variables selected for the present study are reaction temperature, initial concentration of catalyst and working pressure. Temperature is the most significant factor in the esterification process, and its influence is positive. Pressure influence can be neglected, and the catalyst concentration has a positive influence on the process. Depending on the temperature value, the influence of the interactions can be more important than that of the other two main effects, pressure and catalyst concentration. Response surface models have been found adequate to represent the yield of ester. The commercial quality of the synthesized product is very similar to that of natural spermaceti. Because of its low cost, this synthesis process is considered, from an economical point of view, very attractive.
The impact of fluid dynamics on the regeneration of automotive fiber coil filters I. Prediction of soot distribution
Authors: Schnitzlein Klaus
Published: August 2005

The detailed knowledge of the soot distribution is an indispensible prerequisite for a study of the impact of fluid dynamics on the regeneration behaviour of ceramic fiber coil filters. As shown by experiments and simulation calculations the soot distribution can be reliably predicted with a mathematical model formulated in terms of the structural parameters as well as of the operating conditions. Furthermore, it is demonstrated that besides its effect on the regeneration behaviour the impact of fluid dynamics on the soot distribution must be considered, too.
Catalytic oxidation of anisole over titanium silicalite‐1
Authors: Vayssilov Georgi N. , Popova Zdravka , Tuel Alain
Published: August 2005

The reaction of anisole hydroxylation with hydrogen peroxide to form methoxyphenols over TS‐1 was studied. Four C1‐C3 alcohols and the two aprotonic solvents acetone and acetonitrile were used. Product conversion was almost proportional to the titanium content of the catalyst sample. The highest conversion and p‐selectivity were observed in ethanol. Some speculations, based on the formation of substrate‐solvent or titanium‐solvent‐oxidant complexes, about the role of the solvent are presented. It was found that in all the solvents studied the p/o ratio increased with time.
Correlation and prediction of synthesis gas solubility in n‐paraffin systems
Authors: Campanella Enrique A.
Published: August 2005

Fluctuation solution theory relates thermodynamics partial derivatives to integrals of molecular direct correlation functions from statistical mechanics. This paper describes an application of that theory for correlating and predicting solubilities of light gases in heavy n‐paraffins. Two of the solvents are complex waxes. Equations from the theory represent the liquid phase, and additional hypothesis are adopted to build a model for the high pressure vapor‐liquid equilibrium. In the correlation mode, the model, based in the fluctuation solution theory, produces a molar fraction of the gas in the liquid phase with an average absolute relative deviation under 3% in a large number of cases. In the prediction mode, when binary parameters are used, errors are on the order of 10%. Overall for n‐paraffins solvents, the model presented in this paper shows a good capacity to correlate experimental solubility and an adequate power to extrapolate lower pressure data when a binary parameter value has been chosen.
Heterogeneously catalyzed oxidative dehydrogenation of isobutyric acid to methacrylic acid: A new application of periodic flow reversal
Authors: Seuffert Wolfgang , Laubersheimer Jürgen , Emig Gerhard
Published: August 2005

The heterogeneously catalyzed oxidative dehydrogenation of isobutyric acid in a fixed bed reactor using molybdenum (Mo) heteropoly acids as catalysts shows a loss of Mo into the gas phase due to the formation of volatile Mo‐complexes under reaction conditions. To avoid this loss of catalyst and to keep the catalytic material in the fixed bed and thus increase the catalyst's lifetime, the process has been performed under periodic flow reversal within the reactor. In this work, periodic flow reversal is tried in a semi‐pilot test reactor as a method to fix the Mo‐compounds in the catalyst bed. The influence of this mode of operation on the temperature profile in the reactor, on conversion, selectivity and yield of the product methacrylic acid is investigated in comparison with the process without periodic flow reversal.
A nonlinear observer for the iron‐catalysed hydrogen peroxide decomposition in a continuous stirred tank reactor
Authors: Neimeier Rolf , Schulz‐Ekloff Günter , Vielhaben Thomas , Thiele Georg
Published: August 2005

The H2O2 concentration for the nonlinear process of the iron‐catalysed hydrogen peroxide decomposition in a continuous stirred tank reactor is estimated using a time‐variant Extended Luenberger‐Observer. The asymptotic stability of the observer, designed by adequate pole‐placement, is demonstratéd by simulation and comparison of the transient behavior of the estimated concentration profiles with those of the nonlinear system. Comparison with measured H2O2 concentrations indicates satisfactory observer dynamics and accuracy with respect to a lower stationary state of the nonlinear process.
A new pigment disperser for high solids paper coating colors
Authors: Duquesnoy Jean‐Alain , Tanguy Philippe Anoré , Thibault Francis , Leuliet Jean‐Claude
Published: August 2005

In paper coating make‐down, a poor dispersion of pigments in coating colors may lead to coater runnability problems. This is manifested by coat defects at the paper surface, excessive coater blade wear, and an over‐consumption of pigments. For this reason, high shear impellers operated at high speed are used, yielding a high energy consumption. A new method to disperse high solids mix at low energy consumption is presented. This method based on the use of a rod impeller scraping the fluid surface in the vessel, is tested on a slurry composed of calcined and delaminated clays up to a solids content of 66.7 wt.% without dispersing aids.
Two Cubic Polymorphs of AlGeLi.
Authors: Tillard Monique , Belin Claude , Spina Laurent , Jia Yong Zhong
Published: August 2005

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Electronic Structure of the Ti1‐xScxNiSn and Zr1‐xScxNiSn Solid Solutions.
Authors: Romaka L. , Stadnyk Yu. , Horyn A. , Shelyapina M. G. , Kasperovich V. S. , Fruchart D. , Hlil E. K. , Wolfers P.
Published: August 2005

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Investigation of Magnetic Phase Transitions in HfFe6Ge6‐Type Gd1‐xErxMn6Sn6 Intermetallics.
Authors: Cakir O. , Dincer I. , Elmali A. , Elerman Y. , Ehrenberg H. , Fuess H.
Published: August 2005

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Formation, Composition and Stability of Mg—Co Compounds.
Authors: Gennari Fabiana C. , Castro Facundo J.
Published: August 2005

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Nanocrystalline FexNi1‐x (x ≤ 0.65) Alloys Formed by Chemical Synthesis.
Authors: Lima Enio Jr. , Drago Valderes , de Lima Joao Cardoso , Fichtner Paulo Fernando Papaleo
Published: August 2005

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Ruthenium(salen)‐Catalyzed Aerobic Oxidative Desymmetrization of meso‐Diols and Its Kinetics.
Authors: Shimizu Hideki , Onitsuka Satoaki , Egami Hiromichi , Katsuki Tsutomu
Published: August 2005

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Aza‐Michael Addition of Chiral Hydrazines to Alkylidene Malonates.
Authors: Prieto Auxiliadora , Fernandez Rosario , Lassaletta Jose M. , Vazquez Juan , Alvarez Eleuterio
Published: August 2005

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Novel Organic Catalysts for the Direct Enantioselective α‐Oxidation of Carbonyl Compounds.
Authors: Sunden Henrik , Dahlin Nils , Ibrahem Ismail , Adolfsson Hans , Cordova Armando
Published: August 2005

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Application of Organocerium Reagents for the Efficient Conversion of Z‐α,β‐Unsaturated Weinreb Amides to Z‐α,β‐Unsaturated Ketones.
Authors: Kojima Satoshi , Hidaka Tsugihiko , Yamakawa Atsushi
Published: August 2005

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Highly Efficient KF/Al2O3‐Catalyzed Versatile Hetero‐Michael Addition of Nitrogen, Oxygen, and Sulfur Nucleophiles to α,β‐Ethylenic Compounds.
Authors: Yang Lei , Xu Li‐Wen , Xia Chun‐Gu
Published: August 2005

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An Efficient, Microwave Assisted Solvent‐Free Synthesis of Polarized Enamines.
Authors: Chanda Kaushik , Dutta Milan Ch. , Karim E. , Vishwakarma J. N.
Published: August 2005

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Ionic Liquid/Water as a Recyclable Medium for Tsuji—Trost Reaction Assisted by Microwaves.
Authors: Liao Meng‐chun , Duan Xin‐hua , Liang Yong‐min
Published: August 2005

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Lewis Base Catalyzed Diastereoselective Strecker‐Type Reaction Between Trimethylsilyl Cyanide and Chiral Sulfinimines.
Authors: Takahashi Eiki , Fujisawa Hidehiko , Yanai Toshiharu , Mukaiyama Teruaki
Published: August 2005

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Fragmentation of Tertiary Cyclopropanol Compounds Catalyzed by Vanadyl Acetylacetonate.
Authors: Kirihara Masayuki , Kakuda Hiroko , Ichinose Motohiro , Ochiai Yuta , Takizawa Shinobu , Mokuya Asuka , Okubo Kumiko , Hatano Akihiko , Shiro Motoo
Published: August 2005

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Synthesis of 1,2‐Diamino‐1‐phenylpropane Diastereoisomers from u‐N‐Trifluoroacetyl‐2‐amino‐1‐phenylpropan‐1‐ol.
Authors: Dufrasne Francois , Neve Jean
Published: August 2005

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Polymer‐Supported Formate and Magnesium: An Efficient Transfer Hydrogenation System for the Facile Reduction of Azo Compounds.
Authors: Srinivasa G. R. , Abiraj K. , Gowda D. Channe
Published: August 2005

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Synthesis and Properties of Substituted 2‐Amino‐5‐nitrosobenzylamines.
Authors: Semichenko E. S. , Gavrilova N. A. , Suboch G. A.
Published: August 2005

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Chemical Oxidation of Fluoroanilines to Fluoroazobenzenes and Fluorophenazines with Potassium Ferricyanide and Potassium Hydroxide.
Authors: Leyva Elisa , Medina Concepcion , Moctezuma Edgar , Leyva Socorro
Published: August 2005

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HNO3/Silica Gel Supported CAN; Oxidative Deprotection of Benzylic Tetrahydropyranyl Ethers under Solvent‐Free Conditions Using Microwaves.
Authors: Heravi Majid M. , Kazemian Pegah , Oskooie Hossein A. , Ghassemzadeh Mitra
Published: August 2005

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Stereospecific Electrochemical Carboxylation of β‐Bromostyrene by Use of Nickel(II) Catalyst.
Authors: Kuang Chunxiang , Yang Qing , Senboku Hisanori , Tokuda Masao
Published: August 2005

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Synthesis and Study of Some New N‐Substituted Imide Derivatives as Potential Anticancer Agents.
Authors: Jindal Dharam Paul , Bedi Vikas , Jit Birinder , Karkra Nalin , Guleria Sheetal , Bansal Ranju , Palusczak Anja , Hartmann Rolf W.
Published: August 2005

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Conventional and Microwave‐Assisted Conversion of Substituted 3‐Amino‐oxazolidin‐2,4‐diones into N′,N′‐Disubstituted α‐Hydroxyhydrazides.
Authors: Kurz Thomas , Widyan Khalid
Published: August 2005

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Highly Efficient and Stereoselective Synthesis of (2Z)‐2‐(Halomethyl)alk‐2‐enoates in Acidic Ionic Liquid.
Authors: Ying Taokei , Bao Weiliang , Wang Zhonghua , Zhang Yongmin
Published: August 2005

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A Highly Stereoselective Preparation of CF3‐Substituted 1‐Aryl‐1,2‐diphenylethenes: Application to the Synthesis of Panomifene.
Authors: Kim Myong Sang , Jeong In Howa
Published: August 2005

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The Effects of Amines on Oxidative Homo‐Coupling of Terminal Alkynes Promoted by Copper Salts.
Authors: Wang Lei , Yan Jincan , Li Pinhua , Wang Min , Su Caina
Published: August 2005

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Derivatives of spiro‐Fused Cyclopropane‐Dibenzocycloheptatriene and ‐Dibenzocyclooctatriene. Synthesis and Properties.
Authors: Pop Mircea , Surugiu Nina Mirela , Pavel Claudia , Negoescu Mirela‐Alina , Razus Alexandru C.
Published: August 2005

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Catalyzed Asymmetric Induction of Planar Chirality: Palladium‐Catalyzed Intramolecular Mizoroki—Heck Reaction of Prochiral (Arene)chromium Complexes.
Authors: Kamikawa Ken , Harada Kenji , Uemura Motokazu
Published: August 2005

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Cyanoacetylene and Its Derivatives. Part 32. Addition of Ammonia and Methylamine to 4‐Hydroxy‐4,4‐diphenyl‐2‐butynenitrile.
Authors: Mal'kina A. G. , Sokolyanskaya L. V. , Kudyakova R. N. , Sinegovskaya L. M. , Albanov A. I. , Shemyakina O. A. , Trofimov B. A.
Published: August 2005

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First Example of Base‐Promoted Tandem Alkylation—Bromination of 2‐Bromothiophene via Halogen Dance Process: A Remarkable Temperature Effect.
Authors: Peyron Corinne , Navarre Jean‐Michel , Van Craynest Nathalie , Benhida Rachid
Published: August 2005

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Synthesis of Chlorinated 2‐(Aminomethyl)‐ and 2‐(Alkoxymethyl)pyrroles.
Authors: Verniest Guido , Claessens Sven , De Kimpe Norbert
Published: August 2005

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Organoiodine(III) Mediated One‐Pot Synthesis of N‐Substituted 2‐Aminothiazoles.
Authors: Prakash Om , Pundeer Rashmi , Chaudhri Vishwas
Published: August 2005

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A Base‐Catalyzed, Direct Synthesis of 3,5‐Disubstituted 1,2,4‐Triazoles from Nitriles and Hydrazides.
Authors: Yeung Kap‐Sun , Farkas Michelle E. , Kadow John F. , Meanwell Nicholas A.
Published: August 2005

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Synthesis and Biological Activities of Some 2‐(Substituted‐phenyl)‐2‐methyl‐4‐ (1,2,4‐triazole‐1‐yl)methane‐1,3‐dioxolane Derivatives.
Authors: Jian Fangfang , Xiao Hailian , Xu Liangzhong , Yu Guanping
Published: August 2005

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New Synthetic Approaches to Functionally Substituted 4,5‐Dihydro‐1,2,3‐oxadiazole 2‐Oxides
Authors: Tartakovskii V. A. , Ermakov A. S. , Strelenko Yu. A. , Vinogradov D. B. , Petrov E. Yu.
Published: August 2005

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Synthesis and Rearrangement of Benzopyrano[4,3‐c]pyrazole Derivatives.
Authors: Rudenko Roman V. , Desenko Sergey M. , Chebanov Valentin A. , Chernenko Vitaly N. , Musatov Vladimir I.
Published: August 2005

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Synthesis and Antimicrobial Activity of New Linearly Fused 6‐Substituted‐3,8‐diacetyl‐4,7‐dimethyl‐2H‐pyrano[6,5‐f]indoles, Their Chemoselective Bromination and Synthesis of 3‐Thiazolylpyranoindoles.
Authors: Gadaginamath Guru S. , Pujar Shashikant R. , Donawade Dundappa S. , Kavali Rajesh R.
Published: August 2005

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Potassium Exchanged Layered Zirconium Phosphate as Catalyst in the Preparation of 4H‐Chromenes.
Authors: Curini Massimo , Epifano Francesco , Chimichi Stefano , Montanari Francesca , Nocchetti Morena , Rosati Ornelio
Published: August 2005

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Efficient and Fast Heck Vinylation of 2‐Bromo‐6‐methylpyridines with Methyl Acrylate. Application to the Synthesis of 6‐Methylcyclopenta[b]pyridinone.
Authors: Robert Nicolas , Hoarau Christophe , Celanire Sylvain , Ribereau Pierre , Godard Alain , Queguiner Guy , Marsais Francis
Published: August 2005

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Polymethylene Bis(4‐dimethylaminopyridinium bromide): Synthesis, Electrochemical and Biological Investigation.
Authors: Sarkunam K. , Nallu M.
Published: August 2005

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Synthesis of Some Novel Azido‐ and Tetrazoloquinoline‐3‐carbonitriles and Their Conversion into 2,4‐Diaminoquinoline‐3‐carbonitriles.
Authors: Mekheimer Ramadan Ahmed , Elgemeie Galal Hamza , Kappe Thomas
Published: August 2005

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On the Synthesis of Some 2‐Arylhydrazono‐3‐oxothieno[2,3‐b]pyridines by Reaction of Nitrilimines with 2‐Mercaptonicotinic Acid.
Authors: Zahra Jalal A. , Thaher Bassam Abu , El‐Abadelah Mustafa M. , Otto Hans‐Hartwig
Published: August 2005

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A Furan Ring Expansion Approach to the Synthesis of Novel Pyridazino‐Psoralen Derivatives.
Authors: Gonzalez‐Gomez Jose C. , Santana Lourdes , Uriarte Eugenio
Published: August 2005

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Antibacterial and Antifungal Activities of New Pyrazolo[3,4‐d]pyridazin Derivatives.
Authors: Akbas Esvet , Berber Ismet
Published: August 2005

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Synthesis, Biological Studies and Molecular Modeling Investigation of 1,3‐Dimethyl‐2,4‐dioxo‐6‐methyl‐8‐(substituted) 1,2,3,4‐Tetrahydro‐[1,2,4]‐triazolo‐[3,4‐f]‐purines as Potential Adenosine Receptor Antagonists.
Authors: Pastorin Giorgia , Bolcato Chiara , Cacciari Barbara , Kachler Sonja , Klotz Karl‐Norbert , Montopoli Christian , Moro Stefano , Spalluto Giampiero
Published: August 2005

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Efficient Methods for the Synthesis of 2‐Hydroxyphenazine Based on the Pd‐Catalyzed N‐Arylation of Aryl Bromides.
Authors: Tietze Mario , Iglesias Alberto , Merisor Elena , Conrad Juergen , Klaiber Iris , Beifuss Uwe
Published: August 2005

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Organometallic Alkylation of 2‐Chloro‐4,6‐dimethoxy‐1,3,5‐triazine: A Study.
Authors: Samaritani Simona , Signore Giovanni , Malanga Corrado , Menicagli Rita
Published: August 2005

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Improved Synthesis of 7,5‐Fused Bicyclic Lactam for Use as Peptidomimetics.
Authors: Seide Wesly , Watson Samuel E.
Published: August 2005

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Straightforward Synthesis of Sulfur Bridged Oligopyrrolic Macrocycles.
Authors: Sanchez‐Garcia David , Koehler Thomas , Seidel Daniel , Lynch Vincent , Sessler Jonathan L.
Published: August 2005

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Reactions of 1‐Alkynylphosphonates with Group (IV) Complexes
Authors: Al‐Quntar Abed Al‐Aziz , Srebnik Morris
Published: August 2005

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Convenient Route to Dialkyl Diselenides from Alkyl Tosylates. Synthesis of Di(cis‐myrtanyl) Diselenide.
Authors: Scianowski Jacek
Published: August 2005

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Application of Vinyl Tris(trimethylsilyl)germanes in Pd‐Catalyzed Couplings.
Authors: Wang Zhizhong , Wnuk Stanislaw F.
Published: August 2005

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Solid Acid Catalyzed Isomerization of R(+)‐Limonene Diepoxides.
Authors: Salomatina Oksana V. , Yarovaya Olga I. , Korchagina Dina V. , Polovinka Marina P. , Barkhash Vladimir A.
Published: August 2005

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Catalysis of the Reaction of Cholesteryl Acetate with 4‐Phenyl‐1,2,4‐triazoline‐3,5‐dione by Lithium Perchlorate.
Authors: Kinart Wojciech J. , Nazarski Ryszard B. , Kinart Cezary M. , Thuong Quang T. , Oszczeda Rafal
Published: August 2005

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Synthesis of α1‐(Cbz‐Aminoalkyl)‐α2‐ (hydroxyalkyl)phosphinic Esters.
Authors: Drag Marcin , Oleksyszyn Jozef
Published: August 2005

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Synthesis of Ribavirin Analogues Containing Amino‐Acid Residues.
Authors: Li Daliang , Bao Hongli , Tan Qitao , Cai Dongmei , You Tianpa
Published: August 2005

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A Simple, Concise, Stereocontrolled Synthesis of (8E,10Z)‐Pentadecadien‐1‐ol Acetate.
Authors: Chavan Subhash P. , Kharul Rajendra K. , Kamat Subhash K. , Kalkote Uttam R. , Kale Ramesh R.
Published: August 2005

For Abstract see ChemInform Abstract in Full Text.
Metallic Nanowires of Nb3Te4: A Nanostructured Chalcogenide.
Authors: Edwards Hannah K. , Salyer Pamela A. , Roe Martin J. , Walker Gavin S. , Brown Paul D. , Gregory Duncan H.
Published: August 2005

For Abstract see ChemInform Abstract in Full Text.
Ga—Ge—Ni
Authors: Gupta K. P.
Published: August 2005

For Abstract see ChemInform Abstract in Full Text.
Heteropolyboranes with the Heavier Group 14 Elements
Authors: Wesemann Lars , Hosmane Narayan S.
Published: August 2005

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The Road to Early‐Transition‐Metal Phosphinimide Olefin Polymerization Catalysts
Authors: Stephan Douglas W.
Published: August 2005

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gem‐Disubstituent Effect: Theoretical Basis and Synthetic Applications
Authors: Jung Michael E. , Piizzi Grazia
Published: August 2005

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Structure—Activity Relationship Studies of Chemical Mutagens and Carcinogens: Mechanistic Investigations and Prediction Approaches
Authors: Benigni Romualdo
Published: August 2005

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Modified BINAP: The How and the Why
Authors: Berthod Mikael , Mignani Gerard , Woodward Gary , Lemaire Marc
Published: August 2005

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Conjugated Oligoenynes Based on the Diethynylethene Unit
Authors: Nielsen Mogens Broendsted , Diederich Francois
Published: August 2005

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Recent Advances in the Total Synthesis of Piperidine Azasugars
Authors: Pearson Morwenna S. M. , Mathe‐Allainmat Monique , Fargeas Valerie , Lebreton Jacques
Published: August 2005

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Chiral‐Auxiliary‐Controlled Diastereoselective Epoxidations
Authors: Adam Waldemar , Zhang Aimin
Published: August 2005

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Recent Advances in Biaryl‐Type Bisphosphine Ligands
Authors: Shimizu Hideo , Nagasaki Izuru , Saito Takao
Published: August 2005

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Methods for the Enantioselective Biocatalytic Production of L‐Amino Acids on an Industrial Scale
Authors: Groeger Harald , Drauz Karlheinz
Published: August 2005

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Solid‐Phase Peptide Synthesis
Authors: Klok Harm‐Anton
Published: August 2005

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Versatile Oligo(N‐substituted) Glycines: The Many Roles of Peptoids in Drug Discovery
Authors: Patch James A. , Kirshenbaum Kent , Seurynck Shannon L. , Zuckermann Ronald N. , Barron Annelise E.
Published: August 2005

For Abstract see ChemInform Abstract in Full Text.
Recent Advances in the Use of Tri(2‐furyl)germane, Triphenylgermane and Their Derivatives in Organic Synthesis
Authors: Yorimitsu Hideki , Oshima Koichiro
Published: August 2005

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Thermoregulated Phase‐Transfer and Thermoregulated Phase‐Separable Catalysis
Authors: Jin Zilin , Wang Yanhua , Zheng Xiaolai
Published: August 2005

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Guanidine Derivatives
Authors: Berlinck R. G. S. , Kossuga M. H. , Nascimento A. M.
Published: August 2005

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Imidic Acids and Derivatives, Isoureas and Derivatives, Sulfur and Selenium Equivalents, and Analogously Substituted Methylenephosphines
Authors: Gilchrist T. L.
Published: August 2005

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Acyclic and Cyclic Ureas
Authors: Sartori G. , Maggi R.
Published: August 2005

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Magnesium Compounds
Authors: Zhang J.‐H. , Keh C. C. K. , Li C.‐J.
Published: August 2005

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Application of Solid‐State Fermentation to Ligninolytic Enzyme Production
Authors: Rodriguez Couto S. , Sanroman M. A.
Published: August 2005

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The Stepwise Supramolecular Organization of Guanosine Derivatives
Authors: Gottarelli Giovanni , Spada Gian Piero
Published: August 2005

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Cyclophosphazenes with P—C Bond(s). Part 1. Synthesis and Reactivity
Authors: Cristau Henri‐Jean , Fruchier Alain , Plenat Francoise , Taillefer Marc , Vicente Virginie
Published: August 2005

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Synthesis and Applications of Phosphazene Compounds
Authors: Kajiwara Meisetsu , Moriya Keiichi
Published: August 2005

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Strained Heteroatom‐Bridged Metallocenophanes
Authors: Manners Ian , Vogel Ulf
Published: August 2005

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Dynamics for the Reactions of Ion Pair Intermediates of Solvolysis
Authors: Richard John P. , Amyes Tina L. , Toteva Maria M. , Tsuji Yutaka
Published: August 2005

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Friedel—Crafts‐Type Mechanism for the Enzymatic Elimination of Ammonia from Histidine and Phenylalanine
Authors: Poppe Laszlo , Retey Janos
Published: August 2005

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Local Dynamics in Polypeptides Studied by Solid State 2H NMR: Side Chain Dynamics of Poly(γ‐benzyl L‐glutamate) and Racemic Poly(γ‐benzyl Glutamate)
Authors: Hiraoki T. , Kitazawa S. , Tsutsumi A.
Published: August 2005

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Colorectal carcinoma screening procedure use among primary care patients
Authors: Lafata Jennifer Elston , Williams L. Keoki , Ben‐Menachem Tamir , Moon Christina , Divine George
Published: August 2005

BACKGROUND

Despite evidence‐based recommendations for colorectal carcinoma screening, population‐based surveys report low screening rates. To the authors' knowledge, the extent to which screening procedures are used by patients seen in primary care is not as clear. The authors estimated the annual and 5‐year colorectal carcinoma screening procedure use among a cohort of primary care patients and evaluated the correlation between patient characteristics and the use of screening procedures.

METHODS

The authors identified a cohort of patients (n = 21,833 patients) ages 55–70 years who had a primary care visit in 2003 and who were enrolled in a health plan for the 5‐year period ending December 31, 2003. Using automated data for the 5‐year period ending December 31, 2003, information on patient sociodemographic characteristics, primary care and health maintenance examination (HME) visits, comorbid diagnoses, income, and screening receipt was compiled. The latter included barium enema, colonoscopy, fecal occult blood testing (FOBT), and flexible sigmoidoscopy use.

RESULTS

Approximately one‐half of insured, primary care patients (54%) received recommended colorectal carcinoma screening procedures over the 5‐year observation period. Among individuals who received screening, colonoscopy was used most frequently (39.9%), followed by flexible sigmoidoscopy testing alone (28.3%) or in combination with FOBT (4.3%). Annual screening rates increased by 3.1% between 1999 and 2003. Among individuals who did not receive recommended colorectal carcinoma screening, 64% had at least 3 HME visits, and 41% received at least 1 FOBT. Increasing HME visits and other primary care visit frequency, along with increasing age, income, male gender, and African‐American race, were associated with screening receipt.

CONCLUSIONS

Significant opportunities exist to increase colorectal carcinoma screening among primary care patients. Cancer 2005. © 2005 American Cancer Society.
A partitioned solution procedure for geothermal reservoir analysis
Authors: Schrefler B. A.
Published: August 2005

The monolithic augmentation approach, when applied to the analysis of geothermal reservoirs, results in an unsymmetric coefficient matrix of the combined equations. The computational difficulties experienced with this approach suggest the use of a partitioned solution procedure. For this purpose, the fully coupled first‐order three‐field system of equations is integrated in the time domain by a two‐point recurrence scheme. The resulting time‐discrete algebraic system is then partitioned in such a way that the coefficient matrix remains symmetric. A stability analysis of the partitioned system is also carried out.
Exponential upwinding and integrating factors for symmetrization
Authors: Carey G. F.
Published: August 2005

Exponential upwinding in the Petrov–Galerkin method for convection diffusion problems is related to the use of integrating factors for transforming the problem to a (symmetric) self‐adjoint form. The technique yields non‐oscillatory approximations on coarse meshes.
The condensation of the boundary element stiffness matrix in FEBEM analysis
Authors: Sharma K. G. , Varadarajan A. , Singh R. B.
Published: August 2005

Two alternatives are discussed to take into consideration symmetry due to shape and loading in the development of the boundary element stiffness matrix. The resulting boundary element stiffness matrix is coupled with the finite element stiffness matrix and the displacements are computed for a circular tunnel. There is a considerable saving in computation time when symmetry is considered by either of the alternatives, but one appears to be preferable to the other.
A note on the imposition of traction boundary conditions when using the FEM for solving incompressible flow problems
Authors: Taylor C. , Rance J. , Medwell J. O.
Published: August 2005

A traction boundary condition is particularly useful when analysing flow governed by the Navier–Stokes equation. For a large range of flow situations, such as fully developed laminar flow in a pipe or far field flow, the values of boundary traction can be evaluated explicitly. The former can be readily determined from the local values of the primitive variables, while the latter corresponds to zero traction. A general approach is advocated where traction boundary conditions can be evaluated as part of the solution procedure and its value is not required, a priori, before the solution can proceed. An iterative procedure for the evaluation and imposition of non‐zero tractions on boundaries, where advection is appreciable, is demonstrated by utilizing the finite element method (FEM) to simulate laminar flow, both steady state and transient, rearward of a downstream‐facing step within a bounded domain.
A simple extension to multidimensional problems of the artificial viscosity due to Lapidus
Authors: Löhner R. , Morgan K. , Peraire J.
Published: August 2005

An artificial viscosity suitable for use in the simulation of multidimensional high‐speed compressible flows by the finite element method is proposed. The form adopted is a consistent extension of the method due to Lapidus.
Extension of a numerical streamline method
Authors: Pearson Carl E.
Published: August 2005

A numerical method based on streamline geometry has previously been found useful for free surface problems. The method is modified here so as to permit large changes in streamline direction, and an example is given in which a two‐dimensional compressible jet impacts on a flat surface. Careful formulation of the boundary conditions is necessary for computational stability.
Exact expression for a two‐dimensional finite‐part integral appearing during the numerical solution of crack problems in three‐dimensional elasticity
Authors: Ioakimidis N. I.
Published: August 2005

An exact expression is derived for the finite‐part integral over a triangular domain S, where r denotes the distance of the points of the triangle from one of its vertices and f is a linear function of the Cartesian co‐ordinates. The more general case where r denotes the distance of the points of the triangle from another constant point inside (or outside) the triangle is also studied and numerical results are presented. These integrals appear during the numerical solution of plane crack problems (under constant or variable pressure distribution) in three‐dimensional elasticity. The availability of exact expressions for these integrals will increase the accuracy of the numerical results and, simultaneously, it will permit us not to use cubature formulae over triangular domains for the numerical solution of the previous class of problems.
On the accurate determination of stress derivatives
Authors: Baudron A. M. , Marcelin J. L. , Trompette P.
Published: August 2005

A precise numerical method to calculate stress derivatives in finite element applications is proposed. This method uses the Green transformation applied to particular integrants.
Shape effect on Morley's element
Authors: Abdalla Hamed , Hassan Kamal
Published: August 2005

A quantitative study of shape effect on the constant‐moment plate‐bending element of Morley is presented. The so‐called eccentricity coefficients were used to express in a very simple form the shape functions and the stiffness matrix of this triangular finite element. Eigenvalues of different shapes of triangles were calculated and the results of this study reaffirm the influence of smallest angle of triangle on the numerical deterioration of its properties.
A singly‐iterative second‐order method of characteristics for unsteady compressible one‐dimensional flows
Authors: Flatt R.
Published: August 2005

Unsteady compressible and frictional pipe flows in the high subsonic range, especially near the choking condition, are delicate to handle with numerical methods. Even the well‐established first‐order characteristics method may not be accurate enough. This communication describes a procedure based on second‐order interpolations using curved characteristics within each numerical space–time mesh. As only one level of iteration is needed, a considerable amount of computing time can be saved.
Finding polynomial roots: A fast algorithm convergent on the complex plane
Authors: Ivanisov Andrey V. , Polishchuk Vadim K.
Published: August 2005

An algorithm is suggested which performs fast calculations of all the roots of a polynomial with maximal computer accuracy using, as the only primary information, the coefficients and the degree of the polynomial. The algorithm combines global as well as local convergences, i.e. it ensures a rapid hit into a small neighbourhood of a root for 2–3 iterations from any random initial approximation and cubic convergence within the neighbourhood. A modification of the method is given which allows the roots of entire functions to be found. A numerical comparison of the method with commonly used methods (Newton–Raphson, Bairstow–Newton, steepest descent) shows its advantages in speed, accuracy and stability both for real and complex polynomials.
A finite element approximation of the Benard problem
Authors: Krishnan R.
Published: August 2005

The finite element method is used to approximate a solution to the Benard problem. Non‐dimensional heat transfer rates are computed over a range of Rayleigh numbers in three cases: when the upper and lower boundaries are rigid, the upper boundary is free while the lower is rigid, and both upper and lower boundaries are free. In the first case, these values are compared with previously reported numerical work using the finite difference method and with experiments.
Preprocessor for the generation of mathematical software
Authors: Aladjem M. A. , Mikhailov M. D.
Published: August 2005

An approach to create automatically computer programs in the field of numerical analysis using Macro‐processor is described and demonstrated. The listing of a simple and useful PASCAL preprocessor is given.
The design of shock‐free supercritical airfoils including viscous effects
Authors: Hassan A. A.
Published: August 2005

A numerical procedure has been developed for the design of shock‐free supercritical airfoil sections with an allowance for viscous effects, provided the boundary layer is fully attached over the airfoil. The method described combines, in an interative process, an inviscid hodograph‐based inverse‐design algorithm (IDA) developed by the author and the inverse‐boundary layer algorithm (LTBLCEQL) by Miner, Anderson and Lewis. Here, the subcritical portion of the inviscid solution is obtained by solving the full stream function equation in a computational plane which is a conformal map of the two‐sheeted hodograph plane. For the supercritical portion, a characteristics calculation is carried out in the hodograph plane. Viscous effects are then incorporated via the displacement surface concept. A Crank–Nicolson type implicit finite difference scheme is utilized to solve the laminar and turbulent boundary layer equation which are expressed in Levy–Lees variables. A transition model allowing for gradual, rather than instantaneous, transition to turbulent flow is also incorporated. The numerical coupling procedure is applied to the design of two airfoil sections for a range of supercritical Mach numbers.
The application of inverse boundary layer methods to the three‐dimensional viscous design problem
Authors: Lekoudis S. G. , Sankar N. L. , Malone J. B.
Published: August 2005

The problem of designing three‐dimensional configurations with specified skin friction is addressed. For wall flows that are boundary layers, the following procedure is described. The input skin friction is used as a target for an inverse boundary layer calculation. The resulting pressure distribution is used as input to an inviscid configuration design procedure. This procedure computes the body geometry. The procedure is demonstrated by modifying the lift of a wing section, in compressible flow.
A quasi three‐dimensional inverse design method using source and vortex integral equations
Authors: Ribaut M. , Martin D.
Published: August 2005

An integral equation method is presented for the quasi three‐dimensional inverse aerofoil and cascade design. Fluid compressibility and vorticity diffusion are introduced by means of sources resp. distribution functions for the boundary vortices. Application of a Taylor development to the kinematical condition, enlarged by an additional source term, leads to a linear equation system for the profile shape and the channel height. Thus, both the velocity distribution and the profile thickness can be prescribed. Several calculations of aerofoil sections and cascades are presented, which illustrate the accuracy and possibilities of the method.
Temperature fields in simulation of butt‐welding of large plates
Authors: Lindgren Lars‐Erik
Published: August 2005

The simulation of butt‐welding of plates has been performed. Temperature fields were calculated by the use of analytical solutions instead of using the finite element method as was done in Reference 1. The analytical solutions were studied in order to find possible simplifications in the thermal analysis. The thermal material properties were assumed to be independent of temperature in the analytical solutions. The heat flow in the welding direction was neglected in one of these solutions. Three different analytical solutions were studied in the five simulations performed. The mechanical analysis was performed by the finite element method. A thermo‐elastoplastic formulation, considering temperature‐dependent mechanical material properties, was adopted. Volume changes due to phase transformations were also accounted for. Change in gap width in front of the moving arc and residual stresses were calculated in the mechanical analysis. It was found that the temperatures could be calculated from analytical solutions if the residual stresses are of interest. The finite element method should be used to calculate temperatures if the change in gap width is of interest. It was also found that the heat flow along the weld could be neglected even for low welding speeds.
Explicit integration and the isoparametric arch and shell elements
Authors: Crisfield M. A.
Published: August 2005

The paper demonstrates that the standard technique for explicitly integrating the isoparametric degenerate–continuum arch element destroys the strain‐free rigid‐body rotation. It is also shown that this difficulty can be overcome with the aid of Irons's ‘isoparametric shell theory’. Although the developments involve an arch, they are also related to isoparametric shells.
The finite element analysis of homogeneous and laminated composite plates using a simple higher order theory
Authors: Ren J. G. , Hinton E.
Published: August 2005

The higher order shear deformation plate‐bending theory introduced by Reddy and others is used as a basis for the development of two new finite elements. This higher order theory allows a parabolic distribution of transverse shear strains through the plate thickness. Solutions obtained using the new elements are compared with exact closed‐form solutions based on three‐dimensional, first and higher order shear deformation plate bending theories.
Numerical algorithms on the crystal multicomputer
Authors: Meyer R. R.
Published: August 2005

The Crystal multicomputer at the Computer Sciences Department of the University of Wisconsin‐Madison allows the exploration of parallel numerical algorithms by providing a collection of loosely‐coupled minicomputers of substantial computing power (currently, twenty VAX 11/750's) that can exchange data in an efficient manner via messages. Very promising results have already been obtained through through the use of Crystal on nonlinear traffic assignment problems. Additional applications of Crystal are in progress for generalized network flow problems. SOR methods for linear programming, and multigrid methods.
Overhead considerations for parallelizing conjugate gradient
Authors: Seager Mark K.
Published: August 2005

A standard preconditioned conjugate gradient (PCG) algorithm for the solution of symmetric linear systems is studied in the context of multi‐processing. It has been observed that the overheads associated with parallel processing can be expensive. Several alternative approaches are taken in order to try to minimize this cost. Examples are given for Cray X‐MP class machines using CRI's standard multitasking library and a new micro‐tasking compiler preprocessor. These approaches to utilizing multiple CPU's are discussed and overhead measurements given. The quite different PCG implementations under multitasking and micro‐tasking are discussed and compared.
Parallelism in finite element modelling
Authors: Carey Graham F.
Published: August 2005

Parallel processes can be identified at several different levels in the computational simulation of physical processes and problems. We first briefly sketch the main steps involved in modelling physical processes and give examples where inherent parallelism is evident. We then proceed more specifically to describe both inherent and induced parallelism that occur when finite element methods are applied to the solution of boundary and evolution problems, and indicate several opportunitites for parallel processing in finite element analysis.
Element stiffness computation on CDC CYBER 205 computer
Authors: Noor Ahmed K. , Peters Jeanne M.
Published: August 2005

An algorithm is presented for the evaluation of the linear stiffness matrices on the CDC CYBER 205 computer. Discussion is focused on the organization of the computation and the mode of storage of the different arrays to take advantage of CYBER 205 pipeline (streaming) capability. The algorithm is based on partitioning the element stiffness matrix by rows and columns into nodal submatrices and generating simultaneously the coefficients in all the nodal partitions for a group of distinct elements. An assessment is made of the performance of the proposed algorithm for generating the stiffness matrices of shear‐flexible shallow shell elements having 5 degrees of freedom per node. The nomenclature used is given in Appendix II.
An efficient program for generating subminimal cycle bases for the flexibility analysis of structures
Authors: Kaveh A.
Published: August 2005

An efficient program is developed for selecting subminimal cycle bases of graphs. In this program an expansion process is used and independent cycles of minimal lengths are generated. The independence is provided by restricting the increase of Betti number by unity in each step of the process.
On thermal stress calculation
Authors: Mulligan Gale P.
Published: August 2005

Least squares smoothing is applied to thermal strain calculation. The smoothing procedure eliminates apparent errors in thermal stresses due to mismatch of thermal and mechanical strain orders which facilitates direct evaluation of results. General procedures are developed and demonstrated for two‐dimensional isoparametric elements. Examples serve to illustrate the effectiveness of the smoothing procedure.
Acceleration of vector sequences by multi‐dimensional Δ2 methods
Authors: Macleod Allan J.
Published: August 2005

Nine different algorithms for the acceleration of vector sequences are considered. All have the property that, in one dimension, they reduce to the standard Aitken Δ2 process. Different rules for deciding when to accelerate are also discussed. Theoretical and practical results show a wide range of performance, but it is shown that certain methods can be recommended for use.