bluuebunny/crossref_metadata_2025_split huggingface dataset:
The stationary three‐dimensional Navier–Stokes equations with a non‐zero constant velocity at infinity
Authors: Amrouche Chérif , Nguyen Huy Hoang 
Published: April 2008

AbstractThis paper is devoted to some mathematical questions related to the three‐dimensional stationary Navier–Stokes equations. Our approach is based on a combination of properties of Oseen problems in ℝ3. Copyright © 2008 John Wiley & Sons, Ltd.
Improved four‐node Hellinger–Reissner elements based on skew coordinates
Authors: Wisniewski K. , Turska E. 
Published: April 2008

AbstractMixed four‐node elements based on the Hellinger–Reissner (HR) functional are developed for stress representations in various coordinates, including the skew, natural and Cartesian ones. The two‐field HR functional is used in the classical form and in the incremental form suitable for non‐linear materials.We argue that the skew coordinates, not the natural ones, should be associated with the natural basis at the element's center. If 5‐ and 7‐parameter stress representations are assumed in these coordinates, then, for a linear elastic case, the homogenous equilibrium equations and the stress form of compatibility equation are satisfied point‐wise.Two mixed four‐node elements are developed and tested:
An assumed stress element (HR5‐S) is developed from the non‐enhanced HR functional, for a 5‐parameter representation of stresses, formally identical as the one used, for example, in Pian and Sumihara [Int. J. Numer. Meth. Engng 1984; 20:1685–1695], but in terms of skew coordinates. This element is very simple and uses a smaller number of parameters, but is equally accurate as the elements by Yuan et al. [Int. J. Numer. Meth. Engng 1993; 36:1747–1763] and by Piltner and Taylor [Int. J. Numer. Meth. Engng 1995; 38:1783–1808].
An assumed stress/enhanced strain element (HR9) is developed from the enhanced HR functional, for a 7‐parameter representation of stress and a 2‐parameter enhanced assumed displacement gradient or enhanced assumed strain enhancement. Various forms of 7‐parameter representations appearing in the literature are reviewed, and we prove that they are linked by a linear onto transformation. The choice of coordinates for the stress and the enhancement turns out to be the crucial factor, and four combinations of coordinates for which the element performs the best are identified.
Both elements are based on the Green strain, and several numerical tests show their good accuracy, in particular, their robustness to shape distortions for coarse meshes. Two update schemes for the multipliers of modes and the incremental constitutive procedure accounting for the plane stress condition for non‐linear materials are tested for large deformation problems. Copyright © 2008 John Wiley & Sons, Ltd.
A Bayesian inference approach to the ill‐posed Cauchy problem of steady‐state heat conduction
Authors: Jin Bangti , Zou Jun 
Published: April 2008

AbstractThis paper studies a Bayesian inference approach to the Cauchy problem in steady‐state heat conduction of probabilistically calibrating the boundary temperature. The prior modeling is achieved via the Markov random field, and its regularizing property is investigated. A hierarchical Bayesian model is adopted for selecting the regularization parameter and detecting the noise level automatically. The posterior state space is explored using the Markov chain Monte Carlo for obtaining relevant statistics. Two augmented Tikhonov regularization methods that could determine the regularization parameter and the noise level are proposed and analyzed. Numerical results indicate that the Bayesian inference approach could yield an accurate estimate of the solution with its uncertainties quantified, and the augmented Tikhonov regularization methods are accurate and flexible. Copyright © 2008 John Wiley & Sons, Ltd.
Locking‐free continuum displacement finite elements with nodal integration
Authors: Krysl P. , Zhu B. 
Published: April 2008

AbstractAn assumed‐strain finite element technique is presented for linear, elastic small‐deformation models. Weighted residual method (reminiscent of the strain–displacement functional) is used to weakly enforce the balance equation with the natural boundary condition and the kinematic equation (the strain–displacement relationship). A priori satisfaction of the kinematic weighted residual serves as a condition from which strain–displacement operators are derived via nodal integration. A variety of element shapes is treated: linear triangles, quadrilaterals, tetrahedra, hexahedra, and quadratic (six‐node) triangles and (27‐node) hexahedra. The degrees of freedom are only the primitive variables (displacements at the nodes). The formulation allows for general anisotropic materials. A straightforward constraint count can partially explain the insensitivity of the resulting finite element models to locking in the incompressible limit. Furthermore, the numerical inf–sup test is applied in select problems and several variants of the proposed formulations (linear triangles, quadrilaterals, tetrahedra, hexahedra, and 27‐node hexahedra) pass the test. Examples are used to illustrate the performance with respect to sensitivity to shape distortion and the ability to resist volumetric locking. Copyright © 2008 John Wiley & Sons, Ltd.
A new insight on the quantum quantitative structure‐properties relationships
Authors: Carbó‐Dorca Ramon , Van Damme Sofie 
Published: April 2008

AbstractThe theoretical basis of quantum Quantitative Structure‐Properties Relationship (QSPR) is analyzed. After setting up a QQSPR operator structure, the first order fundamental QQSPR equation, which turns to be a linear system, is deduced. Some QQSPR algorithms are described afterwards: they are based on the approximate resolution fundamental QQSPR equation. To show the practical computational use of the theory, the definition of a simple QQSPR predictive model is also developed. Finally an application example is given, based on the Cramer steroid set. The new procedures can be easily extended to classical QSPR problems. © 2008 Wiley Periodicals, Inc. Int J Quantum Chem, 2008
Reactivation of partially poisoned nickel catalyst by bleaching earth
Authors: Drozdowski B. , Goraj‐Moszora I. 
Published: April 2008

AbstractThe effect of activated bleaching earth on the hydrogenation kinetics of fats has been studied in a model system containing sodium soaps, phospholipids and allyl isothiocyanate. Both unsupported and supported catalysts were inactivated by these inhibitors. The optimal quantity of adsorbent, when added to the reaction system, caused a maximal increase of hydrogenation rate in the presence of these inhibitors. In the case of partial inactivation of a catalyst with these inhibitors, the addition of bleaching earth resulted in a regeneration of the catalyst’s active surface and an immediate increase in the hydrogenation rate. The effectiveness of this interaction depended upon the inhibitor type, catalyst type and time of contact with catalyst inactivators. The results suggest the positive effect of activated bleaching earth during hydrogenation results from the sorption processes, inhibitor transformations on the adsorbent and direct interaction with the nickel catalyst.
Extraction of tallow from meat meals: I. Assays in bench scale
Authors: Alvarez G. P. I. , Massaldi H. A. , Maymó J. A. 
Published: April 2008

AbstractA laboratory study on solvent extraction of tallow from meat meals is described for both a stirred batch system and a flooded percolation system. The stirred batch system data, interpreted by standard diffusion concepts, show that the extraction process proceeds through a somewhat complex mechanism, which involves at least two types of extractable fat. The results for the percolation system, which show the effect of different operating variables, indicate good yields are possible with a substantially low solvent requirement.
Cocoa butter‐like fats from fractionated cottonseed oil: II. Properties
Authors: Lovegren N. V. , Gajee B. B. , Gray M. S. , Feuge R. O. 
Published: April 2008

AbstractPreviously it was reported that the stearine obtained as a byproduct in the solvent winterization of cottonseed oil is a good starting material for the preparation of cocoa butter‐like fats by way of hydrogenation and fractionation. The composition, physical properties, and compatability with cocoa butter have been determined for some of these fats. While the products contained triglyceride species other than those in cocoa butter, the major components were similar in that they were 2‐oleodisaturated glycerides. The cocoa butter‐like fats underwent slow polymorphic transformations, but made confectionery coatings remarkably resistant to bloom. Cooling curves resembled those of cocoa butter. Hardness was related to melting point; those fats melting below 35 C were softer than cocoa butter at room temperature, but fats melting above 35 C could be made to resemble cocoa butter in hardness. Adding cocoa butter to the cocoa butter‐like fats had little effect on the softening point. X‐Ray diffraction studies of 1:1 mixtures gave no evidence of mixed crystal formation; the long spacings resembled those of mechanical mixtures. In some other mixtures, certain short spacings became more pronounced.
IDENTIFYING SEED UPTAKE PATHWAYS: THE SPREAD OFAGYA AMOAHRICE CULTIVAR IN SOUTHWESTERN GHANA
Authors: MARFO K. A. , DORWARD P. T. , CRAUFURD P. Q. , ANSERE-BIOH F. , HALEEGOAH J. , BAM R. 
Published: April 2008

SUMMARYA study was carried out to identify the factors that contributed to the natural spread and uptake of a rainfed rice variety namedAgya Amoahin the Western Region of Ghana after introduction of a small amount (0.5 kg) of seed in 1987 by a small-scale farmer. Fifteen years after its introduction over 73% of rice farmers had grown the variety in the Western Region. Initial awareness of the variety was created by information provided mainly by friends, seeing the variety grown in fields and from relatives. Seed for initial planting of the variety was purchased from other farmers by 67% of farmers, but in the most recent season 77% of farmers used their own saved seed. Annual incremental income per household from the replacement of the previously most widely grown variety withAgya Amoahwas estimated to be US $282. The results show that informal systems can result in relatively fast spread and extensive uptake. Local seed systems need to be understood to design appropriate activities that are likely to lead to rapid spread and equitable distribution of introduced varieties, irrespective of characteristics such as wealth and kin.
Endoscopic modified Lothrop procedure for repair of lateral frontal sinus cerebrospinal fluid leak
Authors: Anverali J K , Hassaan A A , Saleh H A 
Published: April 2008

AbstractObjective:To describe a previously unreported case of repair of a lateral frontal sinus cerebrospinal fluid leak, using the endoscopic modified Lothrop procedure.Method:Case report of new technique, with reference to the world literature.Results:An effective endoscopic, transnasal repair of a lateral frontal sinus cerebrospinal fluid leak was achieved in a 60-year-old man. The defect was closed with fat, fascia lata and free mucosal grafts. The left nasal cavity was packed and a lumbar drain left in situ post-operatively. The drain and packs were removed one week later and the patient discharged with no complications, and no recurrence at 12 months' follow up.Conclusion:Such cerebrospinal fluid leaks have traditionally been repaired using an external approach with osteoplastic flaps and obliteration of the sinus. We highlight the endoscopic modified Lothrop technique as an effective alternative approach to repair of cerebrospinal fluid leaks in poorly accessible areas of the frontal sinus.
Wrench capabilities of planar parallel manipulators. Part II: Redundancy and wrench workspace analysis
Authors: Firmani Flavio , Zibil Alp , Nokleby Scott B. , Podhorodeski Ron P. 
Published: April 2008

SUMMARYThis part of the paper investigates the wrench capabilities of redundantly actuated planar parallel manipulators (PPMs). The wrench capabilities of PPMs are determined by mapping a hypercube from the torque space into a polytope in the wrench space. For redundant PPMs, one actuator output capability constrains the wrench space with a smaller polytope that is contained inside the overall polytope. Performance indices are derived from six study cases. These indices are employed to analyze the wrench workspace for constant orientation of the mobile platform of the non-redundant 3-RRR PPM, and actuation redundant 4-RRR and 3-RRR PPMs, where the underline indicates the actuated joints. A comparison of the results shows that both of the redundantly-actuated PPMs give better wrench capabilities than the non-redundant PPM. However, it is shown that scaled for the operational cost (wrench capabilities divided by total actuation output) the non-redundant 3-RRR PPM provides the highest maximum reachable force, the 3-RRR PPM produces the highest isotropic force, and the 4-RRR yields the highest reachable moment.
Error analysis and optimal design of a class of translational parallel kinematic machine using particle swarm optimization
Authors: Xu Qingsong , Li Yangmin 
Published: April 2008

SUMMARYIn this paper, the optimization of architectural parameters for a class of translational parallel kinematic machine (PKM) is performed with the particle swarm optimization (PSO) to achieve the best accuracy characteristics. The conventional error transformation matrix (ETM) is derived based on the differentiation of kinematic equations, and a new error amplification index (EAI) over a usable workspace is proposed as an error performance index for the optimization. To validate the efficiency of the PSO method, both the traditional direct search method and the genetic algorithm (GA) are implemented as well. The simulation results not only show the advantages of PSO method for the architectural optimization, but also reveal the necessity to introduce the EAI for the optimal design. And the results are valuable for architectural design of the PKM for machine tool applications.
Intakes of fruits, vegetables and carbohydrate and the risk of CVD
Authors: Joshipura Kaumudi J , Hung Hsin-Chia , Li Tricia Y , Hu Frank B , Rimm Eric B , Stampfer Meir J , Colditz Graham , Willett Walter C 
Published: April 2008

AbstractBackgroundLow-carbohydrate diets could lead to reduced fruit and vegetable intake, which may be protective against CVD. The role of carbohydrate intake in modifying the association between fruits and vegetables and CVD has not been evaluated.ObjectiveTo evaluate whether carbohydrate intake affects the association between fruits and vegetables and CVD.DesignWe included participants from two large prospective studies, the Nurses’ Health Study (NHS) and the Health Professionals’ Follow-Up Study (HPFS). We followed 70 870 eligible NHS females for 16 years and 38 918 eligible HPFS males for 14 years. Diet was assessed from an FFQ updated every 4 years. Our primary outcome was ischaemic CVD (fatal and non-fatal myocardial infarction and ischaemic stroke). We used Cox proportional hazards models to evaluate the relationship between fruits and vegetables and ischaemic CVD within groups with low, moderate or high carbohydrate intake.ResultsFruit intake was strongly related with carbohydrate intake, but vegetables showed a very small correlation. Vegetable intake showed stronger associations with ischaemic CVD among the low carbohydrate group (multivariate risk ratio (RR) = 0·82 for an increment of 3 servings/d; 95 % CI 0·68, 0·99); green leafy vegetables and carotene-rich fruits and vegetables followed a similar pattern. Total fruit intake was associated with a lower risk of ischaemic CVD only among participants with moderate carbohydrate intake (RR = 0·81 comparing extreme quintiles; 95 % CI 0·70, 0·94).ConclusionsTotal vegetables, green leafy vegetables and carotene-rich fruits and vegetables showed stronger associations with ischaemic CVD among the low carbohydrate group. No consistent trends were observed for fruit intake.
Prevalence of obesity and overweight among urban adults in Bulgaria
Authors: Ivanova Lumdila , Dimitrov Plamen , Dellava Jocilyn , Hoffman Daniel 
Published: April 2008

AbstractObjectiveThe prevalence of obesity is increasing in transitional countries, but extensive data on some countries, such as Bulgaria, are still lacking. Therefore, the objective of the present study was to estimate the prevalence of overweight and obesity, relative to gender and income, among adults in Sofia, Bulgaria.DesignCross-sectional survey to collect data on diet, health, BMI and income using a brief questionnaire on diet and income. Data were analysed using analysis of covariance to determine differences within and between income and gender groups.SettingSofia, Bulgaria.SubjectsAdults living in the city of Sofia, Bulgaria.ResultsFor adults 30–60 years of age, 35·1 % were overweight and 6·2 % were obese. The proportion of overweight and obesity was higher among men than women (44·8 % v. 32·4 % and 6·0 % v. 4·7 %, respectively). With respect to income, BMI decreased as income increased. For men, BMI was highest for the lowest and highest income groups, whereas for women lower income was associated with a higher BMI.ConclusionThe prevalence of overweight and obesity appears to be an emerging problem in some sectors of Bulgarian society, based on our data from the largest urban area of the country. These data provide new information on the divergence in health and disease risk in a country that is still economically challenged and may be facing the nutrition transition.
Advances in Primary Recovery: Centrifugation and Membrane Technology
Authors: Roush David J. , Lu Yuefeng 
Published: April 2008

AbstractSignificant and continual improvements in upstream processing for biologics have resulted in challenges for downstream processing, both primary recovery and purification (1). Given the high cell densities achievable in both microbial and mammalian cell culture processes, primary recovery can be a significant bottleneck in both clinical and commercial manufacturing. The combination of increased product titer and low viability leads to significant relative increases in the levels of process impurities such as lipids, intracellular proteins and nucleic acid versus the product. In addition, cell culture media components such as soy and yeast hydrolysates have been widely applied to achieve the cell culture densities needed for higher titers (2,3). Many of the process impurities can be negatively charged at harvest pH and can form colloids during the cell culture and harvest processes. The wide size distribution of these particles and the potential for additional particles to be generated by shear forces within a centrifuge may result in insufficient clarification to prevent fouling of subsequent filters. The other residual process impurities can lead to precipitation and increased turbidity during processing and even interference with the performance of the capturing chromatographic step. Primary recovery also poses significant challenges owing to the necessity to execute in an expedient manner to minimize both product degradation and bioburden concerns. Both microfiltration and centrifugation coupled with depth filtration have been employed successfully as primary recovery processing steps. Advances in the design and application of membrane technology for microfiltration and dead‐end filtration have contributed to significant improvements in process performance and integration, in some cases allowing for a combination of multiple unit operations in a given step. Although these advances have increased productivity and reliability, the net result is that optimization of primary recovery processes has become substantially more complicated. Ironically, the application of classical chemical engineering approaches to overcome issues in primary recovery and purification (e.g., turbidity and trace impurity removal) are just recently gaining attention (4). Some of these techniques (e.g., membrane cascades, pretreatment, precipitation, and the use of affinity tags) are now seen almost as disruptive technologies (5). This paper will review the current and potential future state of research on primary recovery, including relevant papers presented at the 234th American Chemical Society (ACS) National Meeting in Boston.
International Capacity‐Building in Monsoon Science: Advanced Institute on the Asian Monsoon System: Prediction of Change and Variability; Honolulu, Hawaii, 2–11 January 2008
Authors: Boos William , Virji Hassan , Wang Bin 
Published: April 2008

More than 3 billion people in Asia rely on monsoon precipitation for water, and changes in this precipitation influence agriculture, economic activity, and public health. Given trends of population growth, rapid industrialization, and urbanization, it is important for scientists in the Asia‐Pacific region to both stay abreast of advances in monsoon science and develop collaborations to understand and predict the variability of monsoons.Twenty early‐career meteorologists from across the Asia‐Pacific region and North America met 2–11 January 2008 to attend a series of lectures on the Asian monsoon and to explore possibilities for collaboration. The participants were selected from more than 70 applicants from universities, government labs, and meteorological forecast centers in more than 10 countries. Invited faculty from China, India, Japan, Korea, and the United States gave the lectures, with the largest group of lecturers coming from the International Pacific Research Center (IPRC) of the University of Hawai'i. The meeting was held at the East‐West Center, adjacent to the campus of the University of Hawai'i at Manoa.
Vegetarian and Weight‐Loss Diets among Young Adults
Authors: Smith Cheryl F. , Burke Lora E. , Wing Rena R. 
Published: April 2008

AbstractObjective: Young adults frequently experiment with vegetarian and weight‐loss diets. Comparisons of their experiences on these two different diets may help in the development of approaches to improve long‐term adherence to weight‐loss regimens. In the current study vegetarian and weight‐loss diets were compared on how long and how strictly they were followed, and reasons why they were initiated and discontinued.Research Methods and Procedures: From 428 college students surveyed, four groups were delineated: 1) 59 participants had been following a vegetarian diet but not a weight‐loss diet (Vegetarian), 2) 117 participants had tried a weight‐loss diet but not a vegetarian diet (Weight Loss), 3) 133 participants had followed both a vegetarian and a weight‐loss diet (Both), and 4) 119 participants had not tried either diet (Neither).Results: Differences were examined by comparing the Vegetarian and Weight‐Loss groups as well as by comparing the two diets within the Both group. Duration of the vegetarian diet was much greater than the weight‐loss diet; most participants in the Vegetarian group (62%) remained on their diet for more than 1 year, whereas the majority of the Weight‐Loss participants (61%) followed their diet for 1 to 3 months. Similar results were found when comparing the two diets within the Both group. How strictly the two diets were followed, however, did not differ. Analyses revealed that reasons for discontinuing a diet varied; participants were more likely to cite boredom as a reason for discontinuing a weight‐loss diet than a vegetarian diet (53% vs. 5% between groups and 30% vs. 10% within the Both group).Discussion: The longer duration of the vegetarian diet relative to the weight‐loss diet warrants further investigation. Results could possibly be applied to behavioral weight‐loss treatment to improve long‐term maintenance.