bluuebunny/crossref_metadata_2025 huggingface dataset:
Investigating the stability of falling films at round vertical film carriers under high pressure
Authors: Moser Micro , Trepp Christian
Published: August 2005

The instability of a falling film under high pressure (droplet formation) was characterized by the dimensionless Reynolds, Weber, and fluid‐film numbers and could be predicted in a characteristic diagram. Incipient droplet formation was achieved with the given material properties of the system, i.e., at a constant KF number, by increasing the volumetric flowrate of the liquid phase.

The investigations were performed with the material systems α‐tocopherol/CO2 and squalane/CO2 in the pressure ranges between 8 and 35 MPa and 6 and 12 MPa, respectively, at four different temperatures between 313 and 353 K. The volumetric flowrate of the liquid phase was varied between 10 and 300 ml/min, whereas the speed of the supercritical gas phase in counter‐current flow to the falling film in the falling‐film cell was kept constant at 7 mm/s. The high‐pressure falling‐film cell used for this purpose had an external diameter of 104 mm, an internal diameter of 34 mm, and a total length of 710 mm. The diameter and length of the cylindrical falling‐film carrier were 10 and 500 mm, respectively.
Methanol steam‐reforming in a catalytic fixed bed reactor
Authors: Düsterwald H. G. , Höhlein B. , Kraut H. , Meusinger J. , Peters R. , Stimming U.
Published: August 2005

Designing an appropriate methanol steam reformer requires detailed knowledge about the processes within such a reactor. Thus, the axial temperature and concentration gradients and catalyst ageing were investigated. It was found that for a fresh catalyst load, the catalyst located in the reactor entrance was most active during the experiment. The activity of this part of the catalyst bed decreased after some time of operation due to ageing. With further operation, the most active zone moved through the catalyst bed. From the results concerning hydrogen production and catalyst degradation, the necessary amount of catalyst for a mobile PEMFC‐system can be estimated.
Reduction of nitrogen monoxide with methane on In‐HZSM 5 honeycomb catalysts
Authors: Heinisch Rudolf , Jahn Matthias , Wawrzinek Klemens
Published: August 2005

An In‐HZSM 5 honeycomb catalyst is used for the experimental investigations of the NO reduction with methane. The catalyst is prepared by the ion‐exchange method. The influence of temperature and concentration of oxygen and methane is studied. In addition to methane, natural gas is used as reductant for the reduction of nitric oxide. The results are compared with those of other authors who use zeolithe pellets.
Structural Studies of Metallic Nanowires with Synchrotron Radiation.
Authors: Benfield R. E. , Dore J. C. , Grandjean D. , Kroell M.
Published: August 2005

For Abstract see ChemInform Abstract in Full Text.
Crystal Structure and Magnetic Properties of Mo‐Substituted “Ba2(Fe,W)2O6” Double‐Perovskites: A Synchrotron Diffraction, Magnetization and Moessbauer Study.
Authors: Rammeh N. , Bramnik K. G. , Ehrenberg H. , Stahl B. , Fuess H. , Cheikh‐Rouhou A.
Published: August 2005

For Abstract see ChemInform Abstract in Full Text.
The 673 K Isothermal Section of the La—Ni—Sn Ternary System.
Authors: Zhuang Yinghong , Deng Haixia , Liu Jingqi , Yao Qingrong
Published: August 2005

For Abstract see ChemInform Abstract in Full Text.
MnCo2O4 Preparation by Microwave‐Assisted Route Synthesis (MARS) and the Effect of Carbon Admixture.
Authors: Nissinen Terhi A. , Kiros Yohannes , Gasik Michael , Leskelae Markku
Published: August 2005

For Abstract see ChemInform Abstract in Full Text.
Mild Synthesis of Polyfunctional Benzimidazoles and Indoles by the Reduction of Functionalized Nitroarenes with Phenylmagnesium Chloride.
Authors: Dohle Wolfgang , Staubitz Anne , Knochel Paul
Published: August 2005

For Abstract see ChemInform Abstract in Full Text.
Stereoselective Palladium‐Catalyzed Carbocyclization of Allenic Allylic Carboxylates.
Authors: Franzen Johan , Loefstedt Joakim , Falk Jennica , Baeckvall Jan‐E.
Published: August 2005

For Abstract see ChemInform Abstract in Full Text.
[{W(=O)(O2)2(H2O)}2(μ‐O)] 2‐‐Catalyzed Epoxidation of Allylic Alcohols in Water with High Selectivity and Utilization of Hydrogen Peroxide.
Authors: Kamata Keigo , Yamaguchi Kazuya , Hikichi Shiro , Mizuno Noritaka
Published: August 2005

For Abstract see ChemInform Abstract in Full Text.
A Convenient and Efficient Preparation of β‐Substituted α‐Haloenones from Diazodicarbonyl Compounds.
Authors: Lee Yong Rok , Cho Bang Sub , Kwon Hyuk Jin
Published: August 2005

For Abstract see ChemInform Abstract in Full Text.
Nucleophilic Additions to Fused Bicyclic Five‐Membered Ring Oxocarbenium Ions: Evidence for Preferential Attack on the Inside Face.
Authors: Smith Deborah M. , Tran Michelle B. , Woerpel K. A.
Published: August 2005

For Abstract see ChemInform Abstract in Full Text.
Catalytic Deprotection of Protected Alcohols in Water Using Low‐Loading and Alkylated Polystyrene‐Supported Sulfonic Acid.
Authors: Iimura Shinya , Manabe Kei , Kobayashi Shu
Published: August 2005

For Abstract see ChemInform Abstract in Full Text.
Studies in Novel Synthetic Methodologies. Part 19. Selective Removal of N‐Boc Protecting Group from Aromatic Amines Using Silica Gel‐Supported Sodium Hydrogen Sulfate and HY‐Zeolite as Heterogeneous Catalysts.
Authors: Ravindranath N. , Ramesh C. , Reddy M. Ravinder , Das Biswanath
Published: August 2005

For Abstract see ChemInform Abstract in Full Text.
Formation of Manganese—Alkyne Complexes Mediated by Trialkylmanganates and Their Application.
Authors: Nishikawa Toshihiro , Shinokubo Hiroshi , Oshima Koichiro
Published: August 2005

For Abstract see ChemInform Abstract in Full Text.
N‐Bis(methylthio)methylene‐trifluoromethanesulfonylamide CF3SO2N=C(SCH3)2: New Reagent for the Preparation of N‐Trifluoromethylsulfinylimino Carbonic and Thiocarbonic Acids Derivatives.
Authors: Petrik Vitaly N. , Kondratenko Natalia V. , Yagupolskii Lev M.
Published: August 2005

For Abstract see ChemInform Abstract in Full Text.
Efficient Lewis Base Catalyzed Conjugate Addition of Azide Ion to Cyclic Enones in Water.
Authors: Xu Li‐Wen , Xia Chun‐Gu , Li Jing‐Wei , Zhou Shao‐Lin
Published: August 2005

For Abstract see ChemInform Abstract in Full Text.
A New Method for Nitration of Phenolic Compounds.
Authors: Shi Min , Cui Shi‐Cong
Published: August 2005

For Abstract see ChemInform Abstract in Full Text.
Difluoromethyl Phenyl Sulfone as a Selective Difluoromethylene Dianion Equivalent: One‐Pot Stereoselective Synthesis of anti‐2,2‐Difluoropropane‐1,3‐diols.
Authors: Prakash G. K. Surya , Hu Jinbo , Mathew Thomas , Olah George A.
Published: August 2005

For Abstract see ChemInform Abstract in Full Text.
Polycyclic Aromatic Compounds via Radical Cyclizations of Benzannulated Enyne‐Allenes Derived from Ireland—Claisen Rearrangement.
Authors: Yang Yonghong , Petersen Jeffrey L. , Wang Kung K.
Published: August 2005

For Abstract see ChemInform Abstract in Full Text.
Transition Metal Catalyzed Reactions in Organic Synthesis. Part 6. Cobalt‐Mediated Intramolecular [2 + 2 + 2]‐Cycloaddition of Enediynes Towards Linear Anellated Polycycles.
Authors: Eckenberg Peter , Groth Ulrich
Published: August 2005

For Abstract see ChemInform Abstract in Full Text.
2‐Pyrazolines from 1,3‐Dipolar Cycloaddition of Diazomethane to Arylsulfonylethenes.
Authors: Padmavathi Venkatapuram , Sarma Mudigonda Rajagopala , Padmaja Adivireddy , Reddy Dandu Bhaskar
Published: August 2005

For Abstract see ChemInform Abstract in Full Text.
N,N‐Dichloro‐2‐nitrobenzenesulfonamide as the Electrophilic Nitrogen Source for Direct Diamination of Enones.
Authors: Pei Wei , Wei Han‐Xun , Chen Dianjun , Headley Alan D. , Li Guigen
Published: August 2005

For Abstract see ChemInform Abstract in Full Text.
The Chemistry of 1,6‐Dioxapyrenes. Part 3. Scope and Limitations of an Acid Catalyzed Ring‐Closing Reaction.
Authors: Christensen Joern B. , Bechgaard Klaus
Published: August 2005

For Abstract see ChemInform Abstract in Full Text.
Expedient Synthesis of Biginelli‐Type Dihydropyrimidinones Using α‐(Benzotriazolyl)alkyl Urea Derivatives.
Authors: Abdel‐Fattah Ashraf A. A.
Published: August 2005

For Abstract see ChemInform Abstract in Full Text.
Synthesis of Novel 1,4‐Dihydropyrido[3′,2′:5,6]thiopyrano[4,3‐c]pyrazoles and 5H‐Pyrido[3′,2′:5,6]thiopyrano[4,3‐d]pyrimidines as Potential Antiproliferative Agents.
Authors: Primofiore Giampaolo , Marini Anna Maria , Da Settimo Federico , Salerno Silvia , Bertini Daniele , Dalla Via Lisa , Magno Sebastiano Marciani
Published: August 2005

For Abstract see ChemInform Abstract in Full Text.
8‐Fluoro‐4‐hydroxy‐1H‐[1,2,4]triazino[4,5‐a]quinoline‐1,6(2H)‐dione: Synthesis and Reactivity.
Authors: Edmont Dolores , Chenault Jacques
Published: August 2005

For Abstract see ChemInform Abstract in Full Text.
Synthesis, Lipophilicity and Structure of 2,5‐Disubstituted 1,3,5‐Dithiazine Derivatives.
Authors: Winfield Leyte , Zhang Chunming , Reid Christy A. , Stevens Edwin D. , Trudell Mark L. , Izenwasser Sari , Wade Dean
Published: August 2005

For Abstract see ChemInform Abstract in Full Text.
Unusual Tethering Effects in the Schmidt Reaction of Hydroxyalkyl Azides with Ketones: Cation—π and Steric Stabilization of a Pseudoaxial Phenyl Group.
Authors: Katz Christopher E. , Aube Jeffrey
Published: August 2005

For Abstract see ChemInform Abstract in Full Text.
Isolation and Structure Determination of New Jatrophane Diterpenoids from Euphorbia platyphyllos L.
Authors: Hohmann Judit , Forgo Peter , Csupor Dezsoe , Schlosser Gitta
Published: August 2005

For Abstract see ChemInform Abstract in Full Text.
Formal Synthesis of Squalamine from Desmosterol.
Authors: Okumura Kazuo , Nakamura Yutaka , Takeuchi Seiji , Kato Isao , Fujimoto Yoshinori , Ikekawa Nobuo
Published: August 2005

For Abstract see ChemInform Abstract in Full Text.
A Facile Synthesis of a Key Intermediate for (+)‐Biotin via Strecker Reaction.
Authors: Mori Yoshikazu , Kimura Mayumi , Seki Masahiko
Published: August 2005

For Abstract see ChemInform Abstract in Full Text.
Facile Cu(OTf)2‐Catalyzed Preparation of per‐O‐Acetylated Hexopyranoses with Stoichiometric Acetic Anhydride and Sequential One‐Pot Anomeric Substitution to Thioglycosides under Solvent‐Free Conditions.
Authors: Tai Cheng‐An , Kulkarni Suvarn S. , Hung Shang‐Cheng
Published: August 2005

For Abstract see ChemInform Abstract in Full Text.
Discriminative Glycosylation of 3‐(Aryloxy)propane‐1,2‐diols by Choice of a Glycosyl Donor.
Authors: Mereyala Hari Babu , Mamidyala Sreeman Kumar , Chigurupati Krishna Prasad , Srinivasa Sastri R.
Published: August 2005

For Abstract see ChemInform Abstract in Full Text.
Resomycins A—C: New Anthracyclinone Antibiotics Formed by a Terrestrial Streptomyces sp.
Authors: Maskey Rajendra P. , Gruen‐Wollny Iris , Laatsch Hartmut
Published: August 2005

For Abstract see ChemInform Abstract in Full Text.
First Enantiospecific Total Synthesis of the Antitubercular Marine Natural Product Pseudopteroxazole. Revision of Assigned Stereochemistry.
Authors: Davidson James P. , Corey E. J.
Published: August 2005

For Abstract see ChemInform Abstract in Full Text.
B—Fe—Nd (Boron—Iron—Neodymium)
Authors: Raghavan V.
Published: August 2005

For Abstract see ChemInform Abstract in Full Text.
B—Fe—Mo (Boron—Iron—Molybdenum)
Authors: Raghavan V.
Published: August 2005

For Abstract see ChemInform Abstract in Full Text.
Chiral P,N‐Ligands with Pyridine‐Nitrogen and Phosphorus Donor Atoms. Syntheses and Applications in Asymmetric Catalysis
Authors: Chelucci Giorgio , Orru Gianmauro , Pinna Gerard A.
Published: August 2005

For Abstract see ChemInform Abstract in Full Text.
Solid Phase and Soluble Polymers for Combinatorial Synthesis
Authors: Haag Rainer , Hebel Andre , Stumbe Jean‐Francois
Published: August 2005

For Abstract see ChemInform Abstract in Full Text.
Synthetic Applications of Borate Complexes: Resolution of Racemic Diols and Amino Alcohols via Diastereomeric Borate Complexes
Authors: Periasamy Mariappan
Published: August 2005

For Abstract see ChemInform Abstract in Full Text.
Chirality in the Polysilanes
Authors: Fujiki Michiya , Nakashima Hiroshi , Toyoda Seiji , Koe Julian R.
Published: August 2005

For Abstract see ChemInform Abstract in Full Text.
Molecular Basis of Neurotrophin—Receptor Interactions
Authors: Pattarawarapan Mookda , Burgess Kevin
Published: August 2005

For Abstract see ChemInform Abstract in Full Text.
Design and Synthesis of Novel Bioactive Peptides and Peptidomimetics
Authors: Freidinger Roger M.
Published: August 2005

For Abstract see ChemInform Abstract in Full Text.
Novel Palladium Catalysts for Various C—C and C—N Coupling Reactions Using Aryl Chlorides
Authors: Thommen Marc , Blaser Hans‐Ulrich
Published: August 2005

For Abstract see ChemInform Abstract in Full Text.
Novel Easy Preparations of Some Aromatic Iodine Reagents, Widely Applied in Modern Organic Synthesis
Authors: Skulski Lech
Published: August 2005

For Abstract see ChemInform Abstract in Full Text.
The Effects of Protein Stabilizers on Aggregation Induced by Multiple‐Stresses
Authors: Arakawa Tsutomu , Dix Daniel Bernhard , Chang Byeong Seon
Published: August 2005

For Abstract see ChemInform Abstract in Full Text.
Supramolecular Exciton Chirality of Carotenoid Aggregates
Authors: Simonyi Miklos , Bikadi Zsolt , Zsila Ferenc , Deli Jozsef
Published: August 2005

For Abstract see ChemInform Abstract in Full Text.
Magnetic‐Entropy Change in Mn1.1Fe0.9P0.7As0.3‐x Gex.
Authors: Tegus O. , Fuquan B. , Dagula W. , Zhang L. , Brueck E. , Si P. Z. , de Boer F. R. , Buschow K. H. J.
Published: August 2005

For Abstract see ChemInform Abstract in Full Text.
Solid Lipid Nanoparticles: Concepts, Procedures, and Physicochemical Aspects
Authors: Maeder Karsten , Mehnert Wolfgang
Published: August 2005

For Abstract see ChemInform Abstract in Full Text.
The prognostic impact of histology and 1p/19q status in anaplastic oligodendroglial tumors
Authors: McDonald J. Matthew , See Siew Ju , Tremont Ivo W. , Colman Howard , Gilbert Mark R. , Groves Morris , Burger Peter C. , Louis David N. , Giannini Caterina , Fuller Gregory , Passe Sandra , Blair Hilary , Jenkins Robert B. , Yang Helen , Ledoux Alicia , Aaron Joann , Tipnis Ulka , Zhang Wei , Hess Kenneth , Aldape Ken
Published: August 2005

BACKGROUND

It has been reported previously that the combined loss of chromosomal arms 1p and 19q is a significant predictor of outcome for patients with anaplastic oligodendroglial (AO) tumors and that such chromosomal loss correlates with classic histology in AO. The authors sought to determine whether histology was an equivalent or superior predictor of outcome compared with 1p/19q status in 131 patients with AO tumors.

METHODS

The status of 1p and 19q was determined using real‐time, quantitative polymerase chain reaction analysis and/or fluorescence in situ hybridization. Clinical features (response to adjuvant therapy and tumor location) and molecular genetic abnormalities (9p and 10q deletions, overexpression of p53 and epidermal growth factor receptor) were determined on available specimens. Histologic assessments for classic oligodendroglial features were performed by five neuropathologists.

RESULTS

Classic histology was associated closely with 1p/19q loss, as reported previously. Patients who had tumors that were considered classic by at least four of the five neuropathologists showed significantly increased progression‐free and overall survival compared with the patients who had less classic tumors. The authors also tested the correlation between 1p/19q status and outcome in subsets of patients stratified according to classic tumor features. The association of 1p/19q status with survival was related closely to the presence of classic histology. Loss of 1p/19q was predictive of improved outcome only among patients who had tumors with classic histologic features.

CONCLUSIONS

The current results suggested that, in addition to 1p/19q status, histologic features contribute information to the prediction of outcome in patients with AO. Loss of 1p and 19q appeared to be a prognostic marker only in the subset of patients who had AO tumors with classic histologic features. Cancer 2005. © 2005 American Cancer Society.
New aromatase inhibitors as second‐line endocrine therapy in postmenopausal patients with metastatic breast carcinoma
Authors: Carlini Paolo , Bria Emilio , Giannarelli Diana , Ferretti Gianluigi , Felici Alessandra , Papaldo Paola , Fabi Alessandra , Nisticò Cecilia , Di Cosimo Serena , Ruggeri Enzo Maria , Milella Michele , Mottolese Marcella , Terzoli Edmondo , Cognetti Francesco
Published: August 2005

BACKGROUND

New aromatase inhibitors (AI) (second‐generation: formestane and fadrozole; third‐generation: letrozole, anastrozole, vorozole, and exemestane) have been tested in several controlled clinical trials after tamoxifen failure in metastatic breast carcinoma (MBC). They have resulted in better survival compared with megestrol acetate (MEG) in a number of studies. The authors performed a pooled analysis including all the Phase III trials published between 1996 and 2004 evaluating the AIs approved or not by the Food and Drug Administration (FDA) and the European Agency for the Evaluation of Medical Products (EMEA) as second‐line endocrine therapy (ET) for patients with MBC.

METHODS

The overall response rate (ORR) and time to disease progression (TTP) were considered the primary end points, whereas toxicity was regarded as a secondary objective. Relative risk, 95% confidence interval, and heterogeneity were derived using 2 methods.

RESULTS

No significant differences in ORR and TTP were noted in the entire group of 9 trials comparing AI with MEG (3908 patients) and in the 6 trials comparing nonsteroidal AI and MEG (2415 patients). AI yielded significantly more hot flashes than MEG (P = 0.004) but caused significantly less toxicity than MEG in weight gain (P = 0.001), dyspnea (P = 0.008), and peripheral edema (P = 0.03). Significant heterogeneity for nausea, weight gain, dyspnea, and peripheral edema was registered. When steroidal AIs were excluded from the toxicity analysis, nausea maintained its strongly significant heterogeneity (P = 0.0002), whereas weight gain, dyspnea, and peripheral edema lost their significance.

CONCLUSIONS

This pooled analysis suggested that AIs in second‐line ET for patients with MBC do not seem to add any significant benefit to MEG in terms of ORR and TTP. With regard to toxicity, the findings in the current study showed that weight gain, dyspnea, and peripheral edema are more frequent with the use of MEG, whereas hot flashes were more represented using AI. Cancer 2005. © 2005 American Cancer Society.
Computable error bounds for the generalized symmetric eigenproblem
Authors: Matthies H. G.
Published: August 2005

Some rigorous error bounds are described for the generalized symmetric eigenvalue problem, which may be computed at negligible cost during the eigenvalue calculation and may serve as reliable termination criteria for iterative methods. Explicit formulas are given for subspace iteration and a subspace Lanczos method.
Symmetrization of the contained compressible‐fluid vibration eigenproblem
Authors: Felippa C. A.
Published: August 2005

This paper studies the symmetrization of the problem of coupled vibrations of an acoustic fluid enclosed in an elastic container. The container structure is discretized by a displacement finite element formulation and the acoustic fluid by a displacement‐potential formulation. The vibrations of this physically conservative coupled system are governed by an unsymmetric algebraic eigenvalue problem. Eight equivalent symmetric forms of this problem are exhibited. The fluid‐pressure formulation leads to a similar unsymmetric eigenproblem, which in turn can be converted to another eight equivalent symmetric forms.
Subdivision of PDE's on FPS scientific computers
Authors: Gustafson John L.
Published: August 2005

The usefulness of multiprocessors in solving PDE's has become well established. Many iterative and direct methods exhibit performance which is nearly linear with the number of processors; the ‘parallelable’ fraction of the code can be made to approach unity by increasing the problem size. The resulting push for parallel architectures has been inhibited by ‘Amdahl's argument’, which states that because the speed of any task is dominated by its slowest step, parallel computers are inevitably limited by the serial fraction of most problems. Because this fraction varies, computer designers have faced a choice between a generally cost‐effective machine with a balanced parallel/serial ratio, and a potentially faster machine with high parallelism which performs well on a more restricted class of problems. Software and hardware tools now exist to allow configurable ratios of parallel to serial speed. The recent development of low‐cost Class VI scientific computers permits high‐performance multicomputing without sacrificing performance/cost. The economic consequences of Amdahl's argument can be cicumvented in view of a statistical stream of jobs into a configurable system.
Heat exchange effects during underground gasification of thin coal layers
Authors: Ronde H. , Bruining J. , Essink J. P. Oude , Maljaars A. P. E.
Published: August 2005

Heat exchanges affect the gasification process particularly of thin coal layers. Further experimental evidence is presented that heat lost to the surroundings is partly reintroduced into the reaction zone (heat recuperation). This heat recuperation effect has now been quantified by the finite element calculation of the transient temperature distribution. The calculated values show good agreement with the experimental data. The calculation shows, moreover, that the temperature rise in the coal bed above the adiabatic level must be partly attributed to the heat recuperation effect. Therefore, heat recuperation has a significant effect on the gasification reactions.
Free vibration of a plate with arbitrary shape on a finite elastic foundation in consideration of effects of masses of foundation
Authors: Nagaya Kosuke , Takeuchi Jun
Published: August 2005

This paper presents a method for solving vibration problems of a plate with irregular shape lying on an elastic foundation in consideration of effects of masses of foundation. For the foundation, the equation of motion of longitudinal vibrations of a solid is utilized, and the solutions of both the foundation and the plate are joined together by use of the conditions of continuity between the plate and the foundation. The analysis uses the Fourier expansion collocation method given by Nagaya to satisfy the irregular boundary conditions. Numerical calculations have been carried out for general polygonal plates on elastic foundations. The results for the plate on Winkler's foundation are also given to compare both results. It is clarified that there are some discrepancies between the present result which includes foundation inertias and that of Winkler's foundation.
A computational method for solving singular perturbation problems using fourth order finite differences
Authors: Kadalbajoo Mohan K. , Reddy Y. N.
Published: August 2005

A computational method is presented for solving linear singularly perturbed two‐point boundary value problems with a boundary layer on the left end of the interval. The original problem is divided into inner and outer region problems. The reduced problem is solved to obtain the terminal boundary condition. Then, a new inner region problem is created and solved as a two‐point boundary value problem (TPBVP). In turn, the outer region problem is also solved as a TPBVP. Both these problems (TPBVPs) are efficiently solved by employing a fourth order finite difference scheme. The proposed method is iterative on the terminal point. Some numerical examples have been included to demonstrate the applicability of the method.
Inadmissible distortion of solid elements and patch test results
Authors: Peano Alberto
Published: August 2005

Simple formulae are provided in order to detect distorted shapes of solid elements which actually correspond to inadmissible overlapping at vertices. As pathological situations still pass the zero‐order patch test, factors controlling the behaviour of extremely distorted or overlapped elements are discussed.
A mixed time integration method for Timoshenko and Mindlin type elements
Authors: Wright Joseph P.
Published: August 2005

A brief summary of recent developments in numerical methods for doing transient analyses of Timoshenko and Mindlin types of structures is given. The pure shearing behaviour of these structures (with no transverse motion) is identified as the high‐frequency mode which severely restricts the time step in standard explicit time integration methods. A mixed implicit–explicit scheme is proposed as a technique for circumventing this restriction, and it is shown that this scheme is equivalent to an approach suggested by Belytschko and Mindle9.
Non‐isothermal consolidation of unbounded porous media using mapped infinite elements
Authors: Schrefler B. A. , Simoni L.
Published: August 2005

The computer modelling of geothermal reservoir often involves unbounded continua. The traditional approach to such modelling is by simple truncation at a finite boundary. This results in a large number of degrees‐of‐freedom and precludes the efficient use of microcomputers for such simulations. This paper deals with the use of mapped infinite elements for the simulation of the far‐field response. By comparison with an analytical solution, it is shown that an excellent agreement can be achieved in this way using a reduced number of d.o.f., hence allowing for the use of microcomputers in this area. Furthermore, the use of infinite elements allows realistic boundary conditions for the unbounded domain to be set.
Analysis of air film in conveyor pressurized by two parallel slots: Effect of tilting of package both in longitudinal and transverse directions
Authors: Chandra C. J. G. , Seetharamu K. N. , Parameswaran M. A.
Published: August 2005

The effect of the tilting of a package, both in the longitudinal and transverse directions, on the load‐carrying capacity, volume flow rate of the air supply and the location of the centre of pressure in the case of an air film used in conveyer application is analysed by using the finite element method when the supply of air is through two parallel longitudinal slots. The theoretical results agree reasonably well with the available experimental values.
Pollution problem of the p‐ and h–p versions of the finite element method
Authors: Babuška I. , Oh Hae‐Soo
Published: August 2005

The pollution problem of the p‐version of the finite element method is studied. It is shown that the pollution effect can be practically dealt with by a proper mesh design.
On modelling diffusion‐dominated electrochemical problems via fem
Authors: Sani R. L. , Peskin A. P.
Published: August 2005

The application of a Galerkin finite element method with a front tracking adaptive mesh to certain electrochemical engineering problems is discussed. Some preliminary results are presented to illustrate the technique.
Computation of interplanetary hydromagnetic disturbances in a synoptic domain
Authors: Yeh Tyan
Published: August 2005

The constraints on initial and boundary data for magnetic solenoidality are implemented for MHD computation of interplanetary disturbances. The domain of computation is the entire ecliptic plane outside the solar equator. It is a synoptic domain, without cuts as artificial boundaries. The radial co‐ordinate is stretched so that grid points constitute equilateral meshes, to attain the same degree of accuracy in the finite difference approximations for spatial derivatives in orthogonal directions.
A general formulation for incomplete blockwise factorizations
Authors: Eijkhout Victor L.
Published: August 2005

In recent times a number of incomplete blockwise factorization methods have appeared. These are used as preconditioners in iterative methods for the solution of linear systems. This note purports to give a general formulation for incomplete factorizations from which they can be derived. Some computational and theoretical aspects will be touched upon.
Stability properties of some algorithms for the solution of nonlinear dynamic vibration equations
Authors: Wood W. L. , Oduor M. E.
Published: August 2005

This paper describes numerical experiments made to investigate the stability of some time‐stepping algorithms applied to the equation ü + P(u) = 0 representing a nonliner elastic spring. These algorithms would be unconditionally stable when applied to linear problems, but here they may be only conditionally stable. Ways of improving the stability are demonstrated; the effect of linearization is also investigated.
On the use of subcycling for solving the compressible Navier‐Stokes equations by operator‐splitting and finite element methods
Authors: Bristeau M. O. , Glowinski R. , Mantel B. , Periaux J. , Singh G. S.
Published: August 2005

In this paper we discuss the solution of the compressible Navier‐Stokes equations by numerical techniques combining finite element approximations, operator splitting for the time discretization and numerical treatment of the nonlinearities by subcycling, which in this context means that we perform on the basic time discretization interval a time integration by a standard numerical scheme for initial‐value problems (explicit schemes in this paper). Numerical results for flows around a NACA 0012 aerofoil are presented.
Generalized multigrid approaches to nonlinear transient thermal problems
Authors: Huang H. C. , Lewis R. W.
Published: August 2005

For transient thermal problems, discretizing in space by the finite element method yield a system of first‐order ordinary differential equations which can be integrated in time by a finite difference based predictor‐multicorrector scheme. At each time level the temperature field is obtained by solving a set of algebraic equations.

In this paper the multigrid method is adopted for transient thermal problems. In order to model accurately the geometry of practical problems with various material properties, and to use the predictor‐corrector scheme for the nonlinear transient analysis, the generalized multigrid approach, similar to that proposed in Reference 1, is employed. Some examples are included to illustrate the performance of this approach for nonlinear transient problems.
The university of Minnesota programme in computational science
Authors: Patton Peter C.
Published: August 2005

The University of Minnesota installed a Cray‐1A supercomputer in December 1981. In the past five years programmes for research, instruction and public service in computational science and engineering have been developed that utilize the Cray‐1A and successive machines. The University currently operates a Cray‐2 and a Cyber 205.
Boundary elements for non‐linear heat conduction problems
Authors: Wrobel Luiz C. , Brebbia Carlos A.
Published: August 2005

Boundary element formulations employing time‐independent fundamental solutions are becoming popular for treating transient problems described by parabolic or hyperbolic partial differential equations. This paper describes the extension of one such formulation, named the dual reciprocity boundary element method, to non‐linear transient heat conduction problems with temperature‐dependent material parameters and boundary conditions of the radiative type. The original non‐linear diffusion equation is solved in a transform space, where it appears in a pseudo‐linear form, since it contains a modified time variable which is itself a function of position. The problem is solved by using an iterative algorithm of the Newton‐Raphson type.
Boundary integral analysis with orthogonal basis functions
Authors: Dorri B. , Kadambi V.
Published: August 2005

Source strengths in an indirect single‐layer source formulation of the boundary integral method are described in terms of orthogonal functions rather than the conventional first‐ or second‐order polynomials. The least squares method is used to calculate the coefficients of the orthogonal function which optimally satisfy the boundary conditions. A basic formulation with Fourier series basis functions is presented for the two‐dimensional Laplace equation, along with some representative results. A formulation is also presented for the two‐dimensional diffusion equation. Application of the method to the solution of the inverse heat conduction problem is discussed.
Numerical modelling of the heat transfer in and around a steel bar during hot rolling
Authors: Visser J. A. , Mathews E. H.
Published: August 2005

By modelling the heat transfer in and around a hot‐rolled steel bar, the temperature distribution in the bar can be predicted at any stage of the hot rolling process. Knowledge of these temperatures is useful when the process is to be optimized. This paper presents a finite difference simulation of the heat transfer and resulting temperature distribution. The numerical procedure accounts for thermal radiation from the bar, convective heat transfer to the atmosphere and cooling water, and conduction between the moving bar and the mill rolls and manipulators. Measured values for convective heat transfer coefficients are used at the boundaries. The following effects are also accounted for in the procedure: deformation of the bar during rolling, tilting the bar between passes through a mill, cropping the bar and contraction resulting from heat losses. Predicted and measured temperatures correlate favourably.
Natural convective heat transfer over inclined short plates
Authors: Chang Keun‐Shik , Han In‐Cheol
Published: August 2005

A finite‐difference solution for natural convection over a short flat plate heated on both sides is obtained; the plate has an arbitrary inclination angle. The present numerical method is capable of treating the full flow domain efficiently through the use of a plate/plume‐fitted co‐ordinate system. Correlation between the Nusselt and Rayleigh numbers at intermediate Rayleigh number region, previously obtained only through laborious measurements, is now obtained computationally. Variations of the flow patterns, isotherms and local Nusselt number with the inclination angle and the Rayleigh number are presented Results from a Mach‐Zehnder interferometric study are also presented for comparison.
Parametrized multifield variational principles in elasticity: II. Hybrid functionals and the free formulation
Authors: Felippa Carlos A.
Published: August 2005

A one‐parameter family of d‐generalized hybrid/mixed variational principles for linear elasticity is constructed following a domain subdivision. The family includes the d‐generalized Hellinger‐Reissner and potential energy principles as special cases. The parametrized principle is discretized by independently varied internal displacements, stresses and boundary displacements. The resulting finite element equations are studied following a physically motivated decomposition of the stress and internal displacement fields. The free formulation of Bergan and Nygård is shown to be a special case of this element type, and is obtained by assuming a constant internal stress field. The parameter appears as a scale factor of the higher‐order stiffness.
Investigations into the numerical solution of partially saturated, porous‐medium flow
Authors: Dykhuizen R. C.
Published: August 2005

This paper investigates a numerical formulation of the partially saturated, porous‐medium flow equation. It is shown that improper meshing of the region of study may result in nonphysical solutions. These include the nonexistence of any steady solution, unstable steady solutions and even multiple steady solutions. If the mesh size is reduced, each well‐posed problem has only a single steady solution. A limiting value for the numerical cell size, which prevents these nonphysical results, is given. The analysis presented here will be applicable to both the steady flow equation and the transient equation.
First comparisons between numerical modelling and experimental analysis of free convection in a rectangular cavity
Authors: Baggio P. , Bonacina C. , Strada M.
Published: August 2005

Natural convection in rectangular cavities has been the subject of numerous studies carried out using numerical methods, and also of some experimental studies. In general, however, the majority of numerical studies lack comparisons with experimental data. In experimental studies, it is generally the total heat flow exchanged across the cavity that is measured; rarely are local measurements of velocities reported.

In this study the authors have analysed free convection in a rectangular cavity with an aspect ratio of ∼ 5, in which a preset temperature difference is maintained between two vertical walls, and the other walls are insulated. Numerical analysis was carried out using a penalty finite element method, for different values of the Rayleigh number and different meshes. The numerically predicted velocities are compared with the first experimental data obtained for a rectangular cavity filled with silicone oil.
Direct solution procedure for solution of harmonic problems using complete, non‐singular, Trefftz functions
Authors: Cheung Y. K. , Jin W. G. , Zienkiewicz O. C.
Published: August 2005

Boundary approximation solutions using a singular Green function basis have been widely applied to the solution of a variety of linear problems. To avoid the difficulties associated with integration over singularities it is convenient to use sets of non‐singular, complete Trefftz functions, and this procedure has been applied recently with success using an indirect formulation. In the paper we observe that direct formulation is here again possible and that for some problems it performs in a superior way.
A note on a method of solution for convective stability problems
Authors: Kolyshkin A. A. , Vaillancourt Rémi
Published: August 2005

A collocation method, based on Chebȳshev polynomials, previously used to solve the spectral Orr‐Sommerfeld problem, is generalized to a system of coupled equations and is applied effectively to the convective stability problem of a viscous flow. Two cases are considered, namely a vertical layer bounded by two parallel planes and a vertical coaxial channel. The number n of interpolation polynomials used as basis functions in the algorithm can be kept practically constant as the Prandtl number varies over a wide interval; thus the algorithm can be used for problems with high Prandtl numbers.
On a finite element method for the calculation of steady cellular interfaces in the one‐sided model of solidification
Authors: Wheeler A. A. , Winters K. H.
Published: August 2005

In this paper we reconsider the work of Ungar and Brown.15 These authors reported calculations of the non‐linear families of steady‐state solutions of the one‐sided model of unidirectional solidification of a binary alloy. They combined a finite element method with a Landau transformation13 to deal with the free boundary, and predicted the non‐linear solutions using numerical continuation and bifurcation techniques. We show that the numerical scheme that they used to calculate these families is mesh‐dependent when the solid‐liquid interface becomes sufficiently deformed.
A note on localization phenomena and adaptive finite‐element analysis in forming processes
Authors: Zienkiewicz O. C. , Huang G. C.
Published: August 2005

In this paper we show how an adaptive, error‐controlled, mesh‐refinement procedure can be used effectively to capture localization and shear banding phenomena. Use of directionally elongated meshes is also discussed.
Finite‐difference solutions of partial differential equations
Authors: Bhattacharya M. C.
Published: August 2005

This paper reports a novel technique of forming improved finite‐difference solutions of partial differential equations. The technique leads to difference solutions which give better performance and accuracy compared with the difference equations in current use. Furthermore, by introducing a technique of subinterval time‐step elimination, the difference equations can be operated for any length of time step with a negligible increase in the computer store requirement. This novel technique enables formulation of finite‐difference equations for problems involving arbitrary geometry. One, two and three‐dimensional formulations involving unequal nodal spacings have been worked out. Estimation of the truncation error has been compared with other methods.
Computation of the eigenfrequencies of acoustic cavities: A new penalty method
Authors: Cifuentes A. , Coppolino R.
Published: August 2005

A new penalty method for determining the natural frequencies and normal modes of acoustic cavities is presented. The acoustic medium is described in terms of the displacement field. A new easy‐toimplement penalty function method is employed to enforce the irrotationality condition. This new method has significant advantages when compared to classical penalty function methods since it is more stable with respect to the penalty parameter.
Time‐domain boundary element analysis for linear, viscoelastic problem subject to body force
Authors: Sim Woo Jin , Kwak Byung Man
Published: August 2005

A new boundary element formulation in the time domain is presented for the displacement and stress analysis of quasistatic, linear, viscoelastic problems under the action of body forces. The well‐known concept of the particular integral is adopted for an efficient treatment of the volume integral and to improve the numerical accuracy. The stress kernels and particular integrals are derived using the elastic‐viscoelastic correspondence principle. Numerical results are compared with the derived exact solutions to demonstrate the method and its accuracy.
ODE approach to minimum‐weight design of pinned columns in buckling
Authors: Yuan Si
Published: August 2005

The non‐standard ordinary differential equations (ODEs), resulting from minimum‐weight design of pinned columns in buckling, with or without the minimum cross‐section constraints, are converted to an equivalent standard non‐linear ODE system by using trivial ODE and interval mapping techniques. The ODE system is then directly and efficiently solved by the robust ODE code COLSYS. The longitudinal shapes and switching interface points sought are given explicily as part of the solutions with the accuracy satisfying the user pre‐specified error tolerances. Compared with the analytical solutions, the numerical results obtained by this approach can be considered to be numerically exact.
A numerical technique for two‐dimensional transient wave propagation analyses
Authors: Mengi Yalcin , Tanrikulu A. Kamil
Published: August 2005

A numerical technique is proposed for solving two‐dimensional transient wave propagation problems. The technique involves the use of the combination of a transform (such as Fourier, sine, cosine) for one space variable and the method of characteristics. Because of its inclusion of the latter method in the analysis, the proposed technique is capable of describing the sharp variations of the disturbances which may occur in the neighbourhood of wave fronts. In the study, an example problem is presented which involves transient waves in an elastic layer generated by out‐ofplane shear stresses acting on its top surface. The formulation of the example problem is kept general in the sense that the variations of the applied shear tractions in the horizontal direction of the layer and in time are kept arbitrary. In the analysis, the Fourier transform is used for the horizontal co‐ordinate. The numerical results are obtained and presented for the uniform strip loading case. The assessment of the proposed technique is made by obtaining the results for the case in which the width of the strip load is very large compared to the height of the layer, and by comparing them with exact ones. It is found that the proposed technique yields the results which compare very well with the exact ones and that it is capable of describing the sharp variations at the wave fronts.
An improved perturbation technique for eigenvalues of continuous systems
Authors: Bickford William B.
Published: August 2005

A technique that improves the accuracy of the eigenvalue predictions as computed by a first‐order uniform expansion perturbation scheme for a class of eigenvalue problems associated with linear ordinary and partial differential equations is introduced. As suggested by a comparison with the classical Ritz method, the computational accuracy of a usual perturbation technique such as strained parameters can be effectively increased by simply replacing the usual M‐norms appearing in the denominator of the expressions for the first‐order changes in the eigenvalues by the corresponding MP‐norms, where MP is the perturbed M operator. With increasing sizes of the perturbations of the operators L and M of the class of boundary‐value problems considered, this improved perturbation technique produces results of substantially increased accuracy relative to the usual first‐order uniform expansion perturbation techniques. Numerical examples are presented.
Including bolt bending stiffness in finite‐element analysis of flanged connections
Authors: Tenchev Rosen T.
Published: August 2005

The stiffness matrix of a spring constraint is derived that can restrict only rotation in a mesh of finite elements having no rotation as a degree of freedom. It is connected to two nodes of the structure and does not increase the total number of degrees of freedom. To validate the stiffness matrix, a simple 2‐D numerical example is presented which is in excellent agreement with theoretical results.

Integral grey cast iron flanges (BS4504: 1969) are analysed including and not including the bending stiffness of the bolts. The analysis shows that neglecting the bending stiffness of the bolts results in up to 35% error of overestimating the maximum stress in large‐diameter flanges.
A staggered finite‐element solution for water and gas flow in deforming porous media
Authors: Simoni L. , Schrefler B. A.
Published: August 2005

A numerical model for the mechanics of partially saturated porous media is presented where the flow of both fluid phases is taken into account. The attention is focused on the choice of the field variables so that the model may easily be extended to deal with the important case when the gaseous phase is at constant reference pressure and with the limiting case of a fully saturated situation. To solve the semi‐discretized governing differential equation system in the time domain a staggered procedure is presented, which also allows for a straightforward solution of the two aforementioned cases. The stability and convergence analyses of the proposed solution scheme are presented for a 3 degree‐of‐freedom model system. In this way it is possible to assess the behaviour of the proposed solution scheme.
A low‐diffusive and oscillation‐free convection scheme
Authors: Zhu J.
Published: August 2005

A higher‐resolution and bounded discretization scheme is proposed for calculations of incompressible steady flows with finite‐volume methods. The scheme combines a second‐order upstream‐weighted approximation with the first‐order upwind differencing under the control of a convection boundedness criterion. It is easy to implement for calculations of multi‐dimensional flows, and the resulting finite‐difference coefficient matrix is always diagonally dominant. Applications to three test problems, two linear and one non‐linear, and comparisons with two commonly used schemes, hybrid upwind/central differencing and QUICK, demonstrate the capability of the method in capturing steep gradients while maintaining the boundedness of solutions.
Hybrid adaptive poisson grid generation and grid smoothness
Authors: Roache Patrick J , Salari Kambiz , Steinberg Stanly
Published: August 2005

A hybrid technique for adaptive grid generation using a variety of Poisson grid generators is described. The technique ensures that, when adaptivity functions are weak, the adapted grid reverts to an arbitrary specified base grid rather than to the grid produced by the homogeneous elliptic generator. The hybrid technique also serves to expose the weakness of the claim that elliptic grid generators produce smooth grids.