bluuebunny/crossref_metadata_2025_split huggingface dataset:
Nonparametric trend detection in river monitoring network data: a spatio‐temporal approach
Authors: Clement Lieven , Thas Olivier 
Published: June 2008

AbstractSince the introduction of the Water Framework Directive (WFD), regional authorities have to take actions to improve the aquatic environment. In Flanders (Belgium), for instance a Manure Decree (MD) has been introduced to reduce the impact of eutrophication. It is of course important to assess the evolution of the water quality. In this context, we develop a spatio‐temporal method for the assessment of trends in river monitoring network data. The aim is to detect trends on a more regional scale. In contrast with most existing methods used for analysing river data, our model incorporates the spatio‐temporal dependence structure explicitly. An AR(1) process is assumed for the temporal dependence. The spatial dependence is implied by the river topology and the flow direction. The dependence structure is modelled by a state variable which is embedded into an observation model that makes the correlation structure less rigid. An additive model incorporates a nonparametric long‐term trend and it corrects for seasonal effects. To detect when the local trend is beneficial, tests on the first derivative of the nonparametric long‐term trend are performed at each time step. This, however, results in a large number of simultaneous tests. To correct for multiplicity, we propose to use a variant of the free step‐down method of Westfall and Young 1993 to take these dependences into account. The methodology is applied to a case study on the river Yzer (Belgium). A significant decrease in the nitrate concentration is detected after the implementation of the MD. Copyright © 2008 John Wiley & Sons, Ltd.
Cryo‐snap: A simple modified freeze‐fracture method for SEM imaging of membrane cross‐sections
Authors: Ferlita Russell R. , Phipps Donald , Safarik Jana , Yeh Daniel H. 
Published: June 2008

AbstractCross‐sections of thin film polymeric membranes, including reverse osmosis (RO), ultrafiltration (UF), and hollow fiber microfiltration (MF) membranes, are frequently used for both material analysis and for failure and fouling investigation. However, many techniques currently used to prepare cross‐sections are far from ideal and result in distortion at cut surfaces. A modified freeze fracture method (Cryo‐snap), where the specimen is embedded in ice before cleaving, was developed to minimize the stresses put on the sample during fracturing, thereby reducing the distortion to the cross‐section and increasing the resulting detailed resolution. This method was compared to two commonly used sectioning methods, razor sectioning, and direct freeze fracturing. The Cryo‐snap method rapidly yielded cross‐sections with fewer artifacts than the traditional methods and the sample distortion was extremely low. The method is superior for membrane applications. © 2008 American Institute of Chemical Engineers Environ Prog, 2008
Evaluation of the El Paso method for measuring volatile organic compounds from industrial cooling waters
Authors: Sarwar Golam , Torres Vincent M. , Corsi Richard L. 
Published: June 2008

AbstractControlled laboratory experiments were conducted to measure highly reactive volatile organic compounds (VOCs) in industrial cooling waters using four different sampling methods. The sampling methods included collection of samples from the exhaust air of the El Paso column in Summa® canisters and Tedlar™ bags, and collection of samples from the water flow immediately prior to entering the El Paso column in volatile organic analysis vials and 0.5‐L Tedlar bags. Collected samples were analyzed using standard laboratory techniques. Relative accuracies of the methods involving collection of water samples in volatile organic analysis vials and 0.5‐L Tedlar bags were greater than 20%. Relative accuracies of the methods involving collection of gas samples from the El Paso column in Summa canisters and Tedlar bags were less than 20% when concentrations of these compounds in water were equal to or greater than 50 ppbw. Relative accuracies of these methods were less than 10 ppbw when concentrations of these VOCs in water were less than 50 ppbw. © 2008 American Institute of Chemical Engineers Environ Prog, 2008
Simplex space–time meshes in finite element simulations
Authors: Behr Marek 
Published: June 2008

AbstractA straightforward method for generating simplex space–time meshes is presented, allowing arbitrary temporal refinement in selected portions of space–time slabs. The method increases the flexibility of space–time discretizations, even in the absence of dedicated space–time mesh generation tools. The resulting tetrahedral (for 2D problems) and pentatope (for 3D problems) meshes are tested in the context of advection–diffusion equation, and are shown to provide reasonable solutions, while enabling varying time refinement in portions of the domain. Copyright © 2008 John Wiley & Sons, Ltd.
The combined effects of non‐planarity and asymmetry on primary and secondary flows in the small bronchial tubes
Authors: Soni B. , Lindley C. , Thompson D. 
Published: June 2008

AbstractThe laminar flow in the small bronchial tubes is quite complex due to the presence of vortex‐dominated, secondary flows. In this paper, we report the results of a numerical investigation of the simultaneous effects of asymmetric and non‐planar branching on the primary and secondary flows in the small bronchial tubes, i.e. generations 6–12. We simulate steady‐state inspiratory flow at a Reynolds number of 1000 in three‐generation, asymmetric planar and non‐planar bronchial tube models. The non‐planar model was defined by applying a 90° out‐of‐plane rotation to the third‐generation branches. A detailed mesh refinement study was performed in order to demonstrate mesh independence. Significant differences were observed between flows in the planar and non‐planar models. An uneven mass flow distribution was observed in the non‐planar model in contrast to the evenly distributed mass flow in the planar model. The secondary flows created symmetric vortex patterns in the planar model, whereas vortex symmetry was lost in the non‐planar model. These results illustrate the importance of incorporating asymmetry in addition to non‐planarity in the geometric models. Copyright © 2008 John Wiley & Sons, Ltd.
Sigma transformation and ALE formulation for three‐dimensional free surface flows
Authors: Decoene A. , Gerbeau J. F. 
Published: June 2008

AbstractIn this paper we establish a link between the sigma transformation approach and the arbitrary Lagrangian–Eulerian (ALE) approach. For that purpose we introduce the ALE‐sigma (ALES) approach, which consists in an ALE interpretation of the sigma transformation. Taking advantage of this new approach, we propose a general ALES transformation, allowing for a great adaptability of the vertical discretization and therefore overcoming some drawbacks of the classical sigma transformation. Numerical results are presented, showing the advantages of this general coordinate system, as, for example, a better representation of horizontal stratifications. Copyright © 2008 John Wiley & Sons, Ltd.
CFD analysis of an oscillating wing at various reduced frequencies
Authors: Umar Farooq , Hamdani Hossein Raza , Anwar‐ul‐Haque  , Chaudhry Sajid Raza , Parvez Khalid 
Published: June 2008

AbstractThe effect of various reduced frequencies has been examined for an oscillating aspect ratio 10 NACA 0015 wing. An unsteady, compressible three‐dimensional (3D) Navier–Stokes code based on Beam and Warming algorithm with the Baldwin–Lomax turbulence model has been used. The code is validated for the study against published experimental data. The 3D unsteady flow field is simulated for reduced frequency values of 0.1, 0.2 and 0.3 for a fixed mean angle of attack position and fixed amplitude. The type of motion is sinusoidal harmonic. The force coefficients, pressure distributions and flow visualization show that at the given conditions the flow remains attached to the wing surface even at high angles of attack with no clear separation or typical light‐to‐deep category of dynamic stall. Increased magnitude of hysteresis and higher gradients are seen at higher reduced frequencies. The 3D effects are even found at midspan locations. In addition, the rate of decrease in lift near the wing tips compared with the wing root is not much like in the static cases. Copyright © 2008 John Wiley & Sons, Ltd.
Solution to transient Navier–Stokes equations by the coupling of differential quadrature time integration scheme with dual reciprocity boundary element method
Authors: Bozkaya C. , Tezer‐Sezgin M. 
Published: June 2008

AbstractThe two‐dimensional time‐dependent Navier–Stokes equations in terms of the vorticity and the stream function are solved numerically by using the coupling of the dual reciprocity boundary element method (DRBEM) in space with the differential quadrature method (DQM) in time. In DRBEM application, the convective and the time derivative terms in the vorticity transport equation are considered as the nonhomogeneity in the equation and are approximated by radial basis functions. The solution to the Poisson equation, which links stream function and vorticity with an initial vorticity guess, produces velocity components in turn for the solution to vorticity transport equation. The DRBEM formulation of the vorticity transport equation results in an initial value problem represented by a system of first‐order ordinary differential equations in time. When the DQM discretizes this system in time direction, we obtain a system of linear algebraic equations, which gives the solution vector for vorticity at any required time level. The procedure outlined here is also applied to solve the problem of two‐dimensional natural convection in a cavity by utilizing an iteration among the stream function, the vorticity transport and the energy equations as well. The test problems include two‐dimensional flow in a cavity when a force is present, the lid‐driven cavity and the natural convection in a square cavity. The numerical results are visualized in terms of stream function, vorticity and temperature contours for several values of Reynolds (Re) and Rayleigh (Ra) numbers. Copyright © 2008 John Wiley & Sons, Ltd.
The geometric combination of Bayesian forecasting models
Authors: Faria A. E. , Mubwandarikwa E. 
Published: June 2008

AbstractA nonlinear geometric combination of statistical models is proposed as an alternative approach to the usual linear combination or mixture. Contrary to the linear, the geometric model is closed under the regular exponential family of distributions, as we show. As a consequence, the distribution which results from the combination is unimodal and a single location parameter can be chosen for decision making. In the case of Student t‐distributions (of particular interest in forecasting) the geometric combination can be unimodal under a sufficient condition we have established. A comparative analysis between the geometric and linear combinations of predictive distributions from three Bayesian regression dynamic linear models, in a case of beer sales forecasting in Zimbabwe, shows the geometric model to consistently outperform its linear counterpart as well as its component models. Copyright © 2008 John Wiley & Sons, Ltd.
A Single‐Chamber SOFC Stack: Energy Recovery from Engine Exhaust
Authors: Nagao M. , Yano M. , Okamoto K. , Tomita A. , Uchiyama Y. , Uchiyama N. , Hibino T. 
Published: June 2008

AbstractThe feasibility of applying single‐chamber solid oxide fuel cells (SC‐SOFCs) to power generators for exhaust energy recovery was investigated using both model and actual exhaust gases. In the experiments with model exhaust gases, a single cell, Ni‐Ce0.8Sm0.2O1.9/YSZ/La0.8Sr0.2MnO3, was operated in a mixture of gases containing ppm levels of CH4, C2H6, C3H8, C4H10 and O2. The cell performance was considerably affected by the molar ratio of total hydrocarbons to O2, the operating temperature and the gas flow rate. The optimal operating conditions of the SC‐SOFC were found to be similar to those found in actual exhaust from gasoline engines. Thermal and mechanical loading performance tests demonstrated high tolerance towards thermal cycling and breakage of the electrolyte. Performance tests with and without a gas separator suggested that there is no requirement for a gas separator in an actual exhaust. In the experiments with actual exhaust gases, a 12‐cell stack was installed to a 250‐cm3 engine. The open circuit voltages (OCVs) were between 5 and 8 V and independent of the number of revolutions, but were lower than the values expected from the model exhaust results. This was considered to be due to the deviation of the actual exhaust gases from the model gases. Nevertheless, the stack performance was reproducible and stable in the range from 1,500 to 5,500 rpm. The resultant peak power reached above 1 W at 4,500 rpm.
Deregulated expression of miR‐106a predicts survival in human colon cancer patients
Authors: Díaz Raquel , Silva Javier , García José M. , Lorenzo Yolanda , García Vanesa , Peña Cristina , Rodríguez Rufo , Muñoz Concepción , García Fernando , Bonilla Félix , Domínguez Gemma 
Published: June 2008

AbstractMicroRNAs (miRNAs) are noncoding RNAs that regulate expression of target mRNAs and are controlled by tumor suppressors and oncogenes. Altered expression of specific miRNAs in several tumor types and its association with poor prognosis parameters have been reported. Fewer data are available on its impact on patients' survival. We studied the impact of the expression ofmiR‐17‐5p,miR‐106a, andmiR‐126on survival and its correlation with the levels of their target mRNAs and host gene andTP53alterations. We assessed in 110 colon cancer patients the levels ofmiR‐17‐5p,miR‐106a,miR‐126,E2F1, andEGFL7by quantitative real‐time RT‐PCR and loss of heterozygosity (LOH) in theTP53region. Tumor characteristics, disease‐free survival (DFS), and overall survival (OS) were examined in each patient. Altered expression ofmiR‐17‐5p,miR‐106a, andEGFL7was associated with pathological tumor features of poor prognosis. Downregulation ofmiR‐106apredicted shortened DFS (P= 0.03) and OS (P= 0.04).miR‐17‐5pcorrelated with DFS only at early stages (P= 0.07). Inverse correlations were found betweenmiR‐17‐5pandmiR‐106alevels and their target expression,E2F1(P= 0.04 andP= 0.03, respectively). No correlation was found betweenmiR‐126expression and its host gene levels,EGFL7.miR‐106aderegulation was revealed as a marker of DFS and OS independent of tumor stage. The lack of association between expression ofmiR‐126and its host geneEGFL7suggests their regulation by independent stimuli. Inverse correlation betweenmiR‐17‐5pandmiR‐106aandE2F1levels supportsE2F1as a target mRNA for the two miRNAs. © 2008 Wiley‐Liss, Inc.
A Numerical Simulation Model for Shield Tunnelling with Compressed Air Support
Authors: Nagel Felix , Stascheit Janosch , Meschke Günther 
Published: June 2008

AbstractThis paper is concerned with a numerical simulation model (ekate) specifically designed for shield tunnelling in fully and partially saturated soils based upon the Finite Element Method (FEM). The model considers all relevant components – the soil, the lining, the tail void grouting, the hydraulic jacks and different types of face support – involved in shield tunnelling. The surrounding soft soil is formulated as a three‐phase material, consisting of the soil skeleton, pore water and air. This model allows for the simulation of consolidation processes in partially saturated soils as well as of flow of compressed air often used as temporary face support during repair interventions at the cutting wheel. Despite the complexity connected with the relatively high degree of realism of the simulation model, only little effort is required from the user to establish a realistic 3D model for shield tunnelling. To this end an automatic model generator has been developed which allows for a user friendly generation of the discretized model including all components involved and to investigate variants with a minimum effort for the user. The model allows for realistic predictions of settlements and also provides information on deformations and stresses in the ground, the lining and the TBM, respectively. In addition to its use as a prognosis tool in the design process, in particular for tunnelling projects in sensitive urban areas, the model also may be used to assist the driving and steering process in mechanized tunnelling. The paper provides an overview over the main components of the model, the automatic model generator and the tri‐phasic representation of the soil. A simulation of a compressed air intervention of a shield tunnel in soft soil demonstrates the applicability of the model.
Systemverhalten und Prozessoptimierung beim Erddruckschild
Authors: Maidl Ulrich 
Published: June 2008

AbstractEine konsequente Analyse der Prozessdaten kann die Sicherheit, aber auch die Effektivität des Ressourceneinsatzes beim hoch technisierten Schildvortrieb erheblich steigern. Präventive Maßnahmen zur Prozessoptimierung können durch die zeitnahe Analyse des Systemverhaltens während des Bauablaufs rechtzeitig eingeleitet werden. Eine Analyse des Systemverhaltens wird durch die Aufspaltung des Bauablaufs in Teilprozesse und die Definition der Schlüsselprozesse möglich. Im folgenden Artikel wird am Beispiel des Erddruckschilds aufgezeigt, wie beim heutigen Stand der Technik Prozesse realitätsnah simuliert und während der Ausführung unter Einsatz der vorhandenen Mess‐ und Datenerfassungstechnik analysiert werden können.
Implementierung des Sicherheitsmanagements in die Planung und Bauüberwachung am Beispiel des Lainzer Tunnels Baulos LT31 Maxing
Authors: Heissenberger Roman , Lackner Johannes , Koch Daniel 
Published: June 2008

AbstractInnerstädtische Bauvorhaben stellen besonders hohe Ansprüche an alle Projektbeteiligte von der Projektierungs‐ bis hin zur Ausführungsphase. Der Beitrag befasst sich mit dem konsequenten Einsatz von Sicherheitsmanagementwerkzeugen in den einzelnen Projektphasen. Dabei werden sowohl das grundsätzliche Vortriebskonzept mit der Auswahl der Vortriebsmethode und der Stützmittel in der Projektierungsphase als auch die erforderliche Anpassung im Zuge der Ausführungsphase erläutert. Weiterhin wird auf Risikofaktoren eingegangen, die sich aus den vorhandenen Randbedingungen (Grundwassersituation, Ausführungsqualität) ergeben, und Maßnahmen erläutert, die im Zuge der Ausführung das Gefährdungspotenzial minimieren.
Elliniko Extension of Athens Metro – Project Description, Structuring and Implementation
Authors: Leoutsakos George , Le Van Cuong , Doulakis Ioannis 
Published: June 2008

AbstractThe present paper describes the main aspects of a metro extension project in Athens – extension of line 2 to Elliniko. The general project characteristics – resembling the character of typical metro projects in a congested urban environment – the project benefits, the geology and geotechnical information, the construction methods and other special issues are presented, while the impacts of archaeology and the searching and deactivation of bombs buried from the World War II offer challenges that need to be addressed with minimum impact to the project. The project organization and structuring is also presented for a multi contract implementation with one main contractor and several smaller ones, while the project funding, budget‐cost breakdown and time schedule aspects are also addressed and compared to previous projects.
A common cortactin gene variation confers differential susceptibility to severe asthma
Authors: Ma Shwu‐Fan , Flores Carlos , Wade Michael S. , Dudek Steven M. , Nicolae Dan L. , Ober Carole , Garcia Joe G.N. 
Published: June 2008

AbstractGenomic regions with replicated linkage to asthma‐related phenotypes likely harbor multiple susceptibility loci with relatively minor effects on disease susceptibility. The 11q13 chromosomal region has repeatedly been linked to asthma with five genes residing in this region with reported replicated associations. Cortactin, an actin‐binding protein encoded by the CTTN gene in 11q13, constitutes a key regulator of cytoskeletal dynamics and contractile cell machinery, events facilitated by interaction with myosin light chain kinase; encoded by MYLK, a gene we recently reported as associated with severe asthma in African Americans. To evaluate potential association of CTTN gene variation with asthma susceptibility, CTTN exons and flanking regions were re‐sequenced in 48 non‐asthmatic multiethnic samples, leading to selection of nine tagging polymorphisms for case‐control association studies in individuals of European and African descent. After ancestry adjustments, an intronic variant (rs3802780) was significantly associated with severe asthma (odds ratio [OR]: 1.71; 95% confidence interval [CI]: 1.20–2.43; p=0.003) in a joint analysis. Further analyses evidenced independent and additive effects of CTTN and MYLK risk variants for severe asthma susceptibility in African Americans (accumulated OR: 2.93, 95% CI: 1.40–6.13, p=0.004). These data suggest that CTTN gene variation may contribute to severe asthma and that the combined effects of CTTN and MYLK risk polymorphisms may further increase susceptibility to severe asthma in African Americans harboring both genetic variants. Genet. Epidemiol. 2008. © 2008 Wiley‐Liss, Inc.
Ecstasy‐related deficits in the updating component of executive processes
Authors: Montgomery Catharine , Fisk John E. 
Published: June 2008

AbstractAimsResearch shows that users of ecstasy (MDMA) exhibit deficits in executive processes. The updating component appears to be particularly susceptible. Less is known about the precise nature of such deficits. The present study sought to determine if ecstasy‐related deficits in memory updating are related to serial position of items presented, or length of the list of items.MethodSeventy‐three ecstasy/polydrug users and seventy‐three non‐ecstasy users completed tasks of verbal and spatial memory running memory, recalling the most recent items, in lists of varying and unknown length. Participants were categorised according to letter and spatial span (four, five or six), producing six sub‐samples for analysis.ResultsEcstasy‐polydrug users were impaired in four out of the six sub‐sample analyses. Three of these were due to impaired recall of earlier serial positions.ConclusionsThe results of the present study provide further support for updating deficits in ecstasy‐polydrug users. The results are suggestive of a breakdown in the maintenance of information in working memory in terms of chunking; it appears that ecstasy/polydrug users are as able as non‐ecstasy users to form memory ‘chunks’ from the items, but that such chunks are not retained as effectively. Copyright © 2008 John Wiley & Sons, Ltd.