bluuebunny/crossref_metadata_2025_split huggingface dataset:
A novel method for automated grid generation of ice shapes for local‐flow analysis
Authors: Ogretim Egemen , Huebsch Wade W. 
Published: February 2004

AbstractModelling a complex geometry, such as ice roughness, plays a key role for the computational flow analysis over rough surfaces. This paper presents two enhancement ideas in modelling roughness geometry for local flow analysis over an aerodynamic surface. The first enhancement is use of the leading‐edge region of an airfoil as a perturbation to the parabola surface. The reasons for using a parabola as the base geometry are: it resembles the airfoil leading edge in the vicinity of its apex and it allows the use of a lower apparent Reynolds number. The second enhancement makes use of the Fourier analysis for modelling complex ice roughness on the leading edge of airfoils. This method of modelling provides an analytical expression, which describes the roughness geometry and the corresponding derivatives. The factors affecting the performance of the Fourier analysis were also investigated. It was shown that the number of sine–cosine terms and the number of control points are of importance. Finally, these enhancements are incorporated into an automated grid generation method over the airfoil ice accretion surface. The validations for both enhancements demonstrate that they can improve the current capability of grid generation and computational flow field analysis around airfoils with ice roughness. Copyright © 2004 John Wiley & Sons, Ltd.
Verification of Euler/Navier–Stokes codes using the method of manufactured solutions
Authors: Roy C. J. , Nelson C. C. , Smith T. M. , Ober C. C. 
Published: February 2004

AbstractThe method of manufactured solutions is used to verify the order of accuracy of two finite‐volume Euler and Navier–Stokes codes. The Premo code employs a node‐centred approach using unstructured meshes, while the Wind code employs a similar scheme on structured meshes. Both codes use Roe's upwind method with MUSCL extrapolation for the convective terms and central differences for the diffusion terms, thus yielding a numerical scheme that is formally second‐order accurate. The method of manufactured solutions is employed to generate exact solutions to the governing Euler and Navier–Stokes equations in two dimensions along with additional source terms. These exact solutions are then used to accurately evaluate the discretization error in the numerical solutions. Through global discretization error analyses, the spatial order of accuracy is observed to be second order for both codes, thus giving a high degree of confidence that the two codes are free from coding mistakes in the options exercised. Examples of coding mistakes discovered using the method are also given. Copyright © 2004 John Wiley & Sons, Ltd.
A stabilized finite element procedure for turbulent fluid–structure interaction using adaptive time–space refinement
Authors: de Sampaio Paulo A. B. , Hallak Patrícia H. , Coutinho Alvaro L. G. A. , Pfeil Michéle S. 
Published: February 2004

AbstractThis paper presents our effort to addressing fluid–structure interaction (FSI) problems by means of computational mechanics. A stabilized finite element formulation is used to solve the incompressible Navier–Stokes equations written in primitive variables. The structure is modelled using rigid‐body dynamic equations solved using a Runge–Kutta method. The distinctive feature of our approach is the combination of large eddy simulation (LES)—based on implicit turbulence modelling—with time–space adaptive techniques in arbitrary Lagrangian Eulerian co‐ordinates (ALE). Three representative numerical examples are presented. The first one is the simulation of turbulent vortex shedding around a fixed obstacle, comparing our two‐dimensional (2D) LES results with experiments and more refined three‐dimensional (3D) numerical solutions. The second example presents an ALE computation with moving boundaries, where we were able to detect the lock‐in phenomenon for an oscillating cylinder driven by periodic vortex shedding. Our final example is the FSI problem associated to the flow around a dominant central span section of the Rio‐Niterói bridge, where we compare our results with experiments performed in a wind tunnel. Copyright © 2004 John Wiley & Sons, Ltd.
Investigating the effects of the supply voltage on the tuning range of a 10‐GHz VCO in 0.18‐μm CMOS technology
Authors: Cabuk A. , Yeo K. S. , Ma J. G. , Do M. A. 
Published: February 2004

AbstractThe design of a 10‐GHz voltage‐controlled oscillator (VCO) for synchronous optical network (SONET) applications is presented in this paper. The circuit is fabricated in 0.18‐μm RF CMOS process and it has a phase noise of −95 dBc/Hz at 1‐MHz offset and a very low power consumption of 2.5 mW from a 1.8‐V supply, excluding the output buffers. The effect of supply voltage on the VCO tuning range and the ways to optimize VCO operation in the SONET system are also investigated. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 40: 448–451, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20002
A novel equivalent circuit model for two‐layered spiral inductor with eddy‐current effect in the substrate
Authors: Ooi Ban‐Leong , Xu Dao‐Xian 
Published: February 2004

AbstractIn this paper, an improved two‐layered spiral inductor lumped‐element circuit model, which takes into account the effect of eddy current within the silicon substrate, is proposed. Physical explanation on the modifications of the circuit is given. Compared to the conventional model, our proposed model provides better agreement between the simulated and measured responses for a sample of circular spiral inductors fabricated using silicon substrate. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 40: 484–487, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20011
Determining the scattered field of dense particles using recursive algorithms
Authors: Meiners Christian , Psilopoulos Jannis , Jacob Arne F. 
Published: February 2004

AbstractSome common and fast recursive methods for solving the scattering problem of many randomly distributed particles are reviewed. The particles are characterized by means of a T‐matrix. The useful range of these algorithms is discussed with respect to the number of scatterers and the packing density. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 40: 523–529, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20023
A New Navigation Method for an Automatic Guided Vehicle
Authors: Wuwei Chen , Mills James K. , Wenwu Shi 
Published: February 2004

AbstractThis paper presents a new navigation method for an automatic guided vehicle (AGV). This method utilizes a new navigation and control scheme based on searching points on an arc. Safety measure indices are defined and are generated from the output of a fuzzy neural network which define the actions the AGV is to take when in the presence of obstacles. The proposed algorithm integrates several functions required for automatic guided vehicle navigation and tracking control and it exhibits satisfactory performance when maneuvering in complex environments. The automatic guided vehicle with this navigation control system not only can quickly process environmental information, but also can efficiently avoid dynamic or static obstacles, and reach targets safely and reliably. Extensive simulation and experimental results demonstrate the effectiveness and correct behavior of this scheme. © 2004 Wiley Periodicals, Inc.
Spatial velocity profile changes along the cord in normal human fetuses: can these affect Doppler measurements of venous umbilical blood flow?
Authors: Pennati G. , Bellotti M. , de Gasperi C. , Rognoni G. 
Published: February 2004

AbstractObjectiveSeveral studies have assumed a parabolic velocity profile through the umbilical vein (UV) to derive the mean spatial velocity that is indispensable for flow rate calculations. However, the structure and arrangement of the umbilical cord suggest that velocity profiles may vary. The aim of this study was to evaluate UV spatial flow velocity profiles at different sites along the umbilical cord.MethodsTen singleton pregnancies with a gestational age between 26 and 34 weeks were included in the study. Ultrasound equipment with an inbuilt function for analysis of the spatial velocity profile along a line located in a fixed plane was used to obtain UV velocity profiles. Velocity profiles were obtained at the placental insertion and in a free intra‐amniotic loop of the cord. Two‐dimensional (2D) velocity distribution coefficients were evaluated as ratios between mean and maximum velocities along the investigated lines.Results2D velocity distribution coefficients at the placental insertion (0.85 ± 0.03) were significantly higher (P < 0.00001) than those obtained from a free loop of cord (0.76 ± 0.03). Values indicated that velocity profiles are approximately flat at the placental insertion and become more parabolic moving downstream. Moreover, profiles become skewed in association with cord curvature and show peculiar biphasic shapes immediately downstream from the placenta.ConclusionsFlow velocity profiles in the UV are not perfectly parabolic and modify along the cord. These characteristics may affect the evaluation of UV blood flow rate. Copyright © 2003 ISUOG. Published by John Wiley & Sons, Ltd.
Quantitative three‐dimensional sonographic assessment of pelvic blood after transvaginal ultrasound‐guided oocyte aspiration: factors predicting risk
Authors: Shalev J. , Davidi O. , Fisch B. 
Published: February 2004

AbstractObjectivesTo evaluate the fluid volume in the pelvis immediately and 3–5 days after transvaginal ultrasound‐guided oocyte aspiration (TOAS) and to identify predictive factors for intraperitoneal bleeding.MethodsThis was a prospective study of 83 infertile women undergoing controlled ovarian hyperstimulation followed by TOAS and embryo transfer (ET). Pelvic blood volume was measured by three‐dimensional (3D) ultrasound examination 3–5 h after TOAS (post‐TOAS), and prior to ET (2–3 days after TOAS; pre‐ET). Pelvic blood volume was then correlated with the following procedure‐related variables: day of hCG administration: number and diameter of ovarian follicles, endometrial thickness, serum estradiol levels; day of TOAS: number of retrieved oocytes, patient's perceived pain (Likert scale), duration of TOAS, diameters (using two‐dimensional (2D) ultrasound) and 3D volume of pelvic fluid; day of ET: 2D diameters and 3D volume of pelvic fluid, perceived pain; pregnancy rate.ResultsThe mean ± SD volume of blood measured by 3D ultrasound after TOAS and before ET was 12.94 ± 16.88 (range, 0–98.00) mL and 19.13 ± 17.84 (range, 0–70.20) mL, respectively. Blood volume in the pelvis correlated most strongly with number of oocytes retrieved (post‐TOAS: P < 0.01; pre‐ET: P < 0.05), followed by pain level (post‐TOAS: P < 0.01), number of follicles (post‐TOAS: P < 0.05) and endometrial thickness (post‐TOAS: P < 0.05). When all study variables were held constant, the number of oocytes and serum estradiol level proved to be significant predictors of the amount of fluid in the pelvis (post‐TOAS/pre‐ET: P < 0.01). If 2D ultrasound was used, the best predictor of fluid volume after TOAS was the width of the fluid scanned in the pelvis (P < 0.001).ConclusionsThe amount of blood in the pelvis following TOAS in the present series was within acceptable clinical limits. The number of retrieved oocytes and pain after TOAS were found to be indicators of patients at risk of excessive bleeding. These findings have important implications for the improvement of postprocedural care. Copyright © 2004 ISUOG. Published by John Wiley & Sons, Ltd.
The effect of vascular constriction on umbilical venous pulsation
Authors: Skulstad S. M. , Kiserud T. , Rasmussen S. 
Published: February 2004

AbstractObjectivesUmbilical venous pulsation is an important sign of hemodynamic compromise, but is also found under normal physiological conditions. Mathematical modeling suggests that vascular compliance is a determinant for pulsation, and we tested this by studying velocity pulsation at three sites on the umbilical vein.MethodsIn a cross‐sectional study of 279 low‐risk pregnancies (20–40 weeks' gestational age) blood flow velocity in the umbilical vein was determined before, within and after the umbilical ring in the fetal abdominal wall, and the incidence and magnitude of pulsation (the difference between the maximum and minimum velocity during a pulse, and pulsatility index) were noted. Based on the fact that the vessel cross‐sectional area is an important determinant of compliance, we measured the diameter and time‐averaged maximum velocity to reflect variation in diameter and compliance at the three sites.ResultsThe incidence of umbilical venous pulsation was higher at the umbilical ring in the abdominal wall (242/279, 87%, 95% CI 82–90) than in the cord (43/198, 22%, 95%CI 16–27) or intra‐abdominally (84/277, 30%, 95% CI 25–36) (P < 0.001). When pulsation was observed intra‐abdominally, the pulsatility was not different from that at the umbilical ring (P = 0.16). However, the lowest pulsatility was found in the cord vein (P < 0.0001), where the largest vein diameter was found.ConclusionThe high incidence of venous pulsation at the umbilical ring where diameter and compliance are low supports the suggestion that local compliance is an important factor influencing pulsation in fetal veins. Copyright © 2003 ISUOG. Published by John Wiley & Sons, Ltd.
Multidirectional kinematics of the glenohumeral joint during simulated simple translation tests: Impact on clinical diagnoses
Authors: Moore Susan M. , Musahl Volker , McMahon Patrick J. , Debski Richard E. 
Published: February 2004

AbstractAt the end ranges of motion, the glenohumeral capsule limits translation of the humeral head in multiple directions. Since the 6‐degree of freedom kinematics of clinical tests are commonly utilized to diagnose shoulder injuries, the objective of this study was to determine the magnitude and repeatability of glenohumeral joint kinematics during a simulated simple anteroposterior translation test in the anterior and posterior directions. A magnetic tracking system was used to determine the kinematics of the humerus with respect to the scapula in eight cadaveric shoulders. At 60° of glenohumeral abduction and 0° of flexion/extension, a clinician applied anterior and posterior loads to the humerus at 0°, 30°, and 60° of external rotation until a manual maximum (simulating a simple translation test) was achieved. Prior to each test, the reference position of the humerus shifted posteriorly 1.8 ± 2.0 and 4.1 ± 3.8 mm at 30° and 60° of external rotation, respectively. Anterior translation decreased significantly (p < 0.05) from 18.2 ± 5.3 mm at 0° of external rotation to 15.5 ± 5.1 and 9.9 ± 5.5 mm at 30° and 60°, respectively. However, no significant differences were detected between the posterior translations of 13.4 ± 6.4, 17.1 ± 5.0, and 15.8 ± 6.0 mm at 0°, 30°, and 60° of external rotation, respectively. Coupled translations (perpendicular to the direction of loading) at 0° (6.1 ± 4.0 and 3.8 ± 2.9 mm), 30° (4.7 ± 2.7 and 5.9 ± 3.1 mm), and 60° (2.3 ± 2.3 and 5.0 ± 3.5 mm) of external rotation were in the inferior direction in both the anterior and posterior directions, respectively. Based on the data obtained, performing a simulated simple translation test should result in coupled inferior translations and anterior translations that are a function of external rotation. The low standard deviations demonstrate that the observed translations should be repeatable. Furthermore, capsular stretching or injury to the anterior–inferior region of the capsule should be detectable during clinical examination if excessive coupled translations exist or no posterior shift of the reference position with external rotation is noted. © 2004 Orthopaedic Research Society. Published by Elsevier Ltd. All rights reserved.
Estimating the abundances of large herbivores in the Kruger National Park using presence–absence data
Authors: Tosh Cheryl A. , Reyers Belinda , van Jaarsveld Albert S. 
Published: February 2004

AbstractConservation planning and practice rely heavily on abundance information generated at local scales for decision‐making. Unfortunately most distributional data are only provided as presence–absence records at regional or national scales and cannot be used for making local conservation decisions. To date, two methods have been proposed for estimating local abundances and area of occupancy from coarse‐scale presence–absence data. Kunin (1998) proposed the use of the fractal method, which assumes that species distributions are self‐similar across scales. He & Gaston (2000a), in turn, proposed the use of the negative binomial distribution (NBD) for estimating abundances from presence–absence data collected at different scales. Previously only plant data were used to test these models. In the present study, they were tested using distributional presence–absence, as well as abundance data for a selection of large herbivores that have a restricted distribution in the Kruger National Park, South Africa. The results illustrate that the fractal method tends to overestimate areas of occupancy, while the NBD method underestimates the areas of occupancy of all species. This means that there were significant differences between the predictions provided by the two methods. Both these methods rely on the relationship between the area of occupancy and the size of the area over which the survey is conducted, but describe this relationship in a different way. These techniques could prove useful in the field of conservation biology and this study illustrates that these methods can be used on large mammal species and deliver results that are consistent with previous studies on plants.
Priority conservation areas for butterflies (Lepidoptera: Rhopalocera) in the Philippine islands
Authors: Danielsen Finn , Treadaway Colin G. 
Published: February 2004

AbstractEffective representation of all species in local conservation planning is a major challenge, particularly in poorly known but highly fragmented biological ‘hotspots’. Based on 105 months of studies over 49 years, we reviewed the status of 915 species and 910 subspecies of butterflies known in the Philippines. We identified 133 globally threatened and conservation‐dependent endemic Philippine taxa. The current system of 18 priority protected areas provides at least one protected area for 65 of these but no areas for 29 species and 39 subspecies. Of the 133 taxa, 71% do not have a stable population inside a priority site. A total of 29 taxa is endangered or critically endangered; 83% of these do not occur within a priority site. Least protected are the lowland taxa. The minimum network required to include each threatened and conservation‐dependent taxon of butterfly within at least one area would comprise 29 sites. The Sulus and Mindanao hold disproportionate numbers of threatened butterflies. Our findings suggest limited cross‐taxon congruence in complementarity‐derived priority sets. A large proportion of the priority areas for Philippine butterflies do not coincide with known priority areas for mammals and birds. We demonstrate that a better resolved species level classification could reveal numerous ‘new’ priority areas. In tropical island and mountain regions where the distinctiveness of butterfly subspecies is high, significant evolutionary units may be lost unless fine‐scale conservation planning pays attention to well‐defined subspecies.
The relationship between population size and temporal variability in population size
Authors: Reed David H. , Hobbs Gayla R. 
Published: February 2004

AbstractThe relationship between population size and temporal variability in population size was examined using 2387 populations of 203 species from the Global Population Dynamics Database. Population variability, relative to population size, was assayed by regressing the standard deviation of population size against mean population size. Linear regression produced slopes that were less than one in 165 of 203 species. Thus, temporal fluctuations in population size became significantly weaker as population size increased. Similarly, the slope was significantly less than one for a single regression including all 2387 populations, regardless of taxonomic classification. The slopes of the regression lines did not differ for major taxonomic groupings, but the Y‐intercept was significantly lower for birds than for the other taxonomic groupings. Factor analysis was used to examine the highly correlated parameters: data reliability, population size and taxonomic lineage. Population size was obviously the most important parameter affecting temporal variation in population size, data reliability was also very important, but taxonomy was of little or no importance. The relationship between temporal variation in population size and mean population size, predicted from the data, was used to predict the probability of extinction assuming a normal distribution of population sizes. This simple model predicts that populations of vertebrates will have to number in the thousands for long‐term conservation to be effective.
3,5‐Dibenzoyl‐4‐(3‐phenoxyphenyl)‐1,4‐dihydro‐2,6‐dimethylpyridine (DP7) as a new multidrug resistance reverting agent devoid of effects on vascular smooth muscle contractility
Authors: Saponara Simona , Kawase Masami , Shah Anamik , Motohashi Noboru , Molnar Joseph , Ugocsai Katalin , Sgaragli Giampietro , Fusi Fabio 
Published: February 2004

The aim of this study was to investigate the effects of 3,5‐diacetyl‐ (DP1–DP5) and 3,5‐dibenzoyl‐1,4‐dihydropyridines (DP6–DP11) on vascular functionsin vitro, by comparing their mechanical and electrophysiological actions in rat aorta rings and single rat tail artery myocytes, respectively, and to quantify their multidrug resistance (MDR)‐reversing activity in L5178 Y mouse T‐lymphoma cells transfected with MDR1 gene.In rat aorta, the 11 compounds tested, but 3,5‐dibenzoyl‐4‐(3‐phenoxyphenyl)‐1,4‐dihydro‐2,6‐dimethylpyridine (DP7), 3,5‐dibenzoyl‐4‐(3‐chlorophenyl)‐1,4‐dihydro‐2,6‐dimethylpyridine (DP9), 3,5‐dibenzoyl‐4‐(4‐chlorophenyl)‐1,4‐dihydro‐2,6‐dimethylpyridine (DP10) and 3,5‐dibenzoyl‐4‐phenyl‐1,4‐dihydro‐2,6‐dimethylpyridine (DP11), antagonized 60 mMK+(K60)‐induced contraction in a concentration‐dependent manner, with IC50(M) values ranging between 5.65 × 10−7and 2.23 × 10−5.The 11 dihydropyridines tested, but DP7, inhibited L‐type Ca2+current recorded in artery myocytes in a concentration‐dependent manner, with IC50(M) values ranging between 1.12 × 10−6and 6.90 × 10−5.The K+‐channel opener cromakalim inhibited the Ca2+‐induced contraction in K30 but not that evoked in K60. On the contrary, DP7 was ineffective in both experimental conditions.When the rings were preincubated with 1 mMNi2+plus 1μMnifedipine, the response to phenylephrine was significantly reduced by 2,5‐di‐t‐butyl‐1,4‐benzohydroquinone (BHQ), a well‐known endoplasmic reticulum Ca2+‐ATPase inhibitor. DP7 had no effects on this model system.In L5178 MDR cell line, the 11 dihydropyridines tested, but 3,5‐diacetyl‐4‐(2‐nitrophenyl)‐1,4‐dihydro‐2,6‐dimethylpyridine (DP1), 3,5‐diacetyl‐4‐(3‐phenoxyphenyl)‐1,4‐dihydro‐2,6‐dimethylpyridine (DP2) and 3,5‐diacetyl‐4‐(3‐chlorophenyl)‐1,4‐dihydro‐2,6‐dimethylpyridine (DP4), exhibited an MDR‐reversing activity, with IC50values ranging between 3.02 × 10−7and 4.27 × 10−5, DP7 being the most potent.In conclusion, DP7 may represent a lead compound for the development of potent dihydropyridine MDR chemosensitizers devoid of vascular effects.British Journal of Pharmacology(2004)141, 415–422. doi:10.1038/sj.bjp.0705635