bluuebunny/crossref_metadata_2025_split huggingface dataset:
The change of dielectric properties of barrier coatings during the initial state of immersion
Authors: Strunz W. , Schiller C. A. , Vogelsang J. 
Published: February 2008

AbstractThe initial state of immersion of seven commercially available barrier coatings was monitored using electrochemical impedance spectroscopy (EIS). Within the first spectra, a fast change of state can be detected at low frequencies. This non‐stationarity can be eliminated with an evaluation procedure, known as the Z‐HIT algorithm, resulting in causal spectra which can be interpreted reliably and accurately. The spectra of the coatings can be well modeled by a parallel combination of a capacity and a two step continuous time random walk (CTRW‐2) as a relaxation element. The capacity represents the pure dielectric properties of the coating material which are not affected by the penetrating electrolyte solution. This part of the evaluated coating capacity remains constant during the soaking. In contrast, the parameters of the CTRW‐2 change during water uptake and can be attributed to pores and free sites within the coating material. This separation into parts which are affected by the penetrating solvent and parts which can be described by an ideal dielectric material reflects the inhomogeneous nature of the coatings under test.In the entire measured frequency range the change of the dielectric properties of the investigated systems can be modeled by the same equivalent circuit which was used formerly to interpret impedance spectra of barrier coatings in the saturated state, requiring four to five adjustable parameters for simulating the experimental data.
Novel repair method for technical enamels based on sol–gel and sol‐dispersion coatings
Authors: Benfer S. , Fürbeth W. , Schütze M. 
Published: February 2008

AbstractThe aim of the work presented here is the development of a novel repair method for technical enamels by using chemical nanotechnology. Good adhesion of coatings requires good wettability of the substrate by the repair solution. This was achieved by different pre‐treatments of the steel substrates. Low sintering temperatures of the coatings can be ensured by the use of nanoparticle‐based systems. Based on liquid metal alkoxides, a colloidal alumina sol and metal salts homogeneous sols with up to seven enamel compounds were prepared. The sols were brush coated onto plain and partly enamelled steel substrates and sintered in a furnace, by inductive heating or an IR emitter. Thin (single layer ≪ 1µm) crack‐free layers were obtained on nearly all substrates independent of the sintering conditions investigated. The local sintering methods (IR emitter, inductive heating) allow to produce multiple coating systems in short times. Electrochemical impedance spectroscopy (EIS) provides evidence of the protective effect of these layers compared to the bare substrate, but as a result of their chemical composition the layers are not stable in the electrolytic environment for longer times. The thickness of such multiple coatings (20 layers, ≈ 8 µm) is still small compared to that of a technical enamel. Therefore, sol dispersion systems containing powder particles and sol components are applied on top of the sol–gel layers to increase the thickness of the sintered layers.
Influence of the chromate content in cement on the corrosion behaviour of steel in concrete
Authors: Schieß P. , Mayer T. F. , Osterminski K. 
Published: February 2008

AbstractChromate, which is known to be an effective corrosion inhibitor in various applications, is contained in cement as a trace element. So far its influence on the corrosion of steel in contact with concrete has not been investigated. However, as the introduction of chromate‐reduced cements has coincided with an increase in corrosion phenomena occurring on steel moulds in precast concrete plants, the question has been raised whether chromate might as well have an influence on the corrosion of reinforcement in hardened concrete.Against this background different experiments for examining the influence of chromate on the corrosion behaviour of steel in synthetic pore solution, fresh and hardened concrete have been carried out. The results showed that the reduction of chromate has different consequences for the time periods of fresh and hardened concrete. During early hydration within the first 12–24 h the natural chloride content of the concrete constituents may be sufficient to start corrosion. Experiments yielded a higher corrosion risk for steel embedded in chromate‐reduced concrete. This first stage is followed by a repassivation as pH rises and chlorides are bound in the course of cement hydration. In hardened concrete no significant influence of the chromate content in the cement on the corrosion behaviour could be found.
Long‐term durability of electrochemical chloride extraction
Authors: Elsener B. 
Published: February 2008

AbstractThis paper presents field data from one of the first well‐documented reinforced concrete structures that has been rehabilitated with electrochemical chloride extraction (ECE) in the year 1989. The results of half‐cell potential mapping measured 1, 5 and nearly 20 years after the ECE treatment show that the reinforcement was completely repassivated after the ECE treatment and remained in fully passive condition. Regarding the efficiency of the ECE treatment an intermittent (current on–off) is beneficial. The question of repassivation of pre‐corroded reinforcement is discussed. According to this and other results from field applications the ECE treatment is effective and – if further chloride ingress is avoided – also durable. For economical reasons it is recommended to apply the non‐destructive ECE treatment in an early state, before delaminations or spalling has occurred.
A benchmarking test for surface treatment products for zinc die cast
Authors: Feser R. , Schulz Ch. 
Published: February 2008

AbstractCorrosion protection of zinc surfaces was successfully done in the past by chromate conversion layers. To reduce the amount of Cr(VI) products in the environment substitution processes have been developed. For the zinc industry it was a question whether surface treatment products are on the market which can substitute the conventional chromating process. A benchmarking test should be performed to show how good the Cr(VI) free products are in comparison to the state of the art process. Several corrosion tests have been performed to show the corrosion behaviour of treated zinc die cast products in comparison to Cr(VI) treated and plain surfaces. Additionally electrochemical measurements have been performed to discriminate further between the products. Especially CoulCount measurements show clearly the protection capability of the various surface treatments. No one of the tested products shows the same good behaviour like Cr(VI) treated products, but the performance of several products looks not bad and has to be proofed further under real service conditions.
A trend toward abrasive nano finishing of plane surfaces with magnetic field energy
Authors: Vahdati M. , Shokuhfar A. 
Published: February 2008

AbstractIn new developed parts, roughness has become an effective parameter and influences the performance of the entire system. Manufacturing of parts with fine surface finish have been a target for many advanced industries. Sometimes, it is difficult to reach highly polished surface quality by conventional methods. One of the newly introduced methods for obtaining fine finished surfaces is nano‐scale finishing with abrasive particles in magnetic fields. It is a relatively new finishing process that can be used to produce efficiently shiny surface quality for certain parts [1]. In this process, the cutting movement is provided by the magnetic field energy of permanent or electric poles. Magnetic abrasive particles (MAPs) are used to remove chips, and polish the work‐piece surface [2, 3]. The work‐piece is in the shape of a flat plane. An apparatus has been designed and made for machining the upper face of the plane. Nd‐Fe‐B magnets are used to establish the magnetic field. An NC machine is applied to create the rotational movement of MAPs in the horizontal plane and maintain the vertical position accurately. Various experiments have been designed to specify the machining characteristics of the MAF process. In these experiments different effective conditions are determined. Permanent magnets with 1.2 T magnetic flux density are used as magnetic poles. Homogeneous mechanical mixture of abrasive powder (Silicon Carbide) and ferromagnetic iron particles are used as the MAPs. The experimental setup was designed for finishing the aluminium alloy AA–6061. Test results indicated that the finishing parameters affect the material removal rate (MRR) and surface roughness.
An optimization technique using the characteristics of genetic algorithm
Authors: Kim G.‐H. , Lee Y.‐S. 
Published: February 2008

AbstractOptimization problems could happen often in discrete or discontinuous search space. Therefore, the traditional gradient‐based methods are not able to apply to this kind of problems. The discrete design variables are considered reasonably and the heuristic techniques are generally adopted to solve this problem, and the genetic algorithm based on stochastic search technique is one of these. The genetic algorithm method with discrete variables can be applied to structural optimization problems, such as composite laminated structures or trusses. However, the discrete optimization adopted in genetic algorithm gives rise to a troublesome task that is a mapping between each strings and discrete variables. And also, its solution quality could be restricted in some cases. In this study, a technique using the genetic algorithm characteristics is developed to utilize continuous design variables instead of discrete design variables in discontinuous solution spaces. Additionally, the proposed algorithm, which is manipulating a fitness function artificially, is applied to example problems and its results are compared with the general discrete genetic algorithm. The example problems are to optimize support positions of an unstable structure with discontinuous solution spaces.
Ascertaining late‐life depressive symptoms in Europe: an evaluation of the survey version of the EURO‐D scale in 10 nations. The SHARE project
Authors: Castro‐Costa Erico , Dewey Michael , Stewart Robert , Banerjee Sube , Huppert Felicia , Mendonca‐Lima Carlos , Bula Christophe , Reisches Friedel , Wancata Johannes , Ritchie Karen , Tsolaki Magda , Mateos Raimundo , Prince Martin 
Published: February 2008

AbstractThe reported prevalence of late‐life depressive symptoms varies widely between studies, a finding that might be attributed to cultural as well as methodological factors. The EURO‐D scale was developed to allow valid comparison of prevalence and risk associations between European countries. This study used Confirmatory Factor Analysis (CFA) and Rasch models to assess whether the goal of measurement invariance had been achieved; using EURO‐D scale data collected in 10 European countries as part of the Survey of Health, Ageing and Retirement in Europe (SHARE) (n = 22,777). The results suggested a two‐factor solution (Affective Suffering and Motivation) after Principal Component Analysis (PCA) in 9 of the 10 countries. With CFA, in all countries, the two‐factor solution had better overall goodness‐of‐fit than the one‐factor solution. However, only the Affective Suffering subscale was equivalent across countries, while the Motivation subscale was not. The Rasch model indicated that the EURO‐D was a hierarchical scale. While the calibration pattern was similar across countries, between countries agreement in item calibrations was stronger for the items loading on the affective suffering than the motivation factor. In conclusion, there is evidence to support the EURO‐D as either a uni‐dimensional or bi‐dimensional scale measure of depressive symptoms in late‐life across European countries. The Affective Suffering sub‐component had more robust cross‐cultural validity than the Motivation sub‐component. Copyright © 2008 John Wiley & Sons, Ltd.
Psychometric properties of the Chinese version of the Swanson, Nolan, and Pelham, version IV scale – parent form
Authors: Gau Susan Shur‐Fen , Shang Chi‐Yung , Liu Shih‐Kai , Lin Chien‐Ho , Swanson James M. , Liu Yu‐Chih , Tu Chang‐Ling 
Published: February 2008

AbstractThis study aimed to establish the psychometric properties of parent ratings on the Chinese version of the Swanson, Nolan, and Pelham IV scale (SNAP‐IV) in a school‐based sample of 3534 students in grades 1 to 8 from two cities and two suburbs in Taiwan and 189 children diagnosed with attention deficit/hyperactivity disorder (ADHD) (aged 6 to 15) consecutively recruited from a medical center in Taipei. Parents completed the Chinese versions of the SNAP‐IV, Strengths and Difficulties Questionnaire, and Child Behavior Checklist. The Chinese SNAP‐IV demonstrated similar three factor structure (Inattention, Hyperactivity/Impulsivity, and Oppositional) as its English version, and satisfactory test–retest reliability (intraclass correlation = 0.59∼0.72), internal consistency (alpha = 0.88∼0.90), concurrent validity (Pearson correlations = 0.56∼0.72), and discriminant validity. Boys scored higher than girls across the eight school grade levels. The SNAP‐IV clearly distinguished children with ADHD from school‐based participants. Comorbidity with oppositional defiant disorder/conduct disorder predicted higher SNAP‐IV scores among children with ADHD. Our findings suggest that the Chinese SNAP‐IV is a reliable and valid instrument for rating ADHD‐related symptoms in both clinical and community settings in Taiwan. Copyright © 2008 John Wiley & Sons, Ltd.
Exploring daily variations of drinking in the Swiss general population. A growth curve analysis
Authors: Heeb Jean‐Luc , Gmel Gerhard , Rehm Jürgen , Mohler‐Kuo Meichun 
Published: February 2008

AbstractThis study aims to address the underlying trajectories of weekly individual drinking patterns by growth models and to relate differences in drinking patterns to socio‐demographic and drinking characteristics of respondents. Data came from a two‐stage stratified random subsample of 747 persons aged 15 years or more from a Swiss study on alcohol consumption using a within‐subject design conducted between March 1999 and July 1999. Beverage specific assessment of daily alcohol consumption was obtained by a weekly drinking diary and other characteristics via telephone interviews. The diary had to be filled out on seven consecutive days. The growth models accounted for up to 37.6% of the initial error variance and provided evidence for two distinct, negatively correlated underlying trajectories of drinking patterns. The first trajectory described an increase in consumption from Monday to Sunday. The second trajectory was about a specific weekend consumption culminating on Saturday with a significantly higher growth rate among young people and heavy episodic drinkers than in other subgroups. Therefore, young and heavy episodic drinkers may be exposed to sudden adverse consequences of alcohol consumption during the weekend. Prevention efforts which are targeted to this subgroup should take its specific drinking pattern into account. Copyright © 2008 John Wiley & Sons, Ltd.
Meta‐analyses of the incidence and prevalence of schizophrenia: conceptual and methodological issues
Authors: Saha Sukanta , Chant David , Mcgrath John 
Published: February 2008

AbstractWhile meta‐analytic techniques are routine in the synthesis of data from randomized controlled trials, there are no clear guidelines on how best to summarize frequency data such as incidence and prevalence estimates. Based on data from two recent systematic reviews of the incidence and prevalence of schizophrenia, this paper explores some of the conceptual and methodological issues related to the meta‐analyses of frequency estimates in epidemiology. Because variations in the incidence and prevalence of disorders such as schizophrenia can be informative, there is a case against collapsing data into one pooled estimate. Variations in frequency estimates can be displayed graphically, or summarized with quantiles around measures of central tendency. If pooled estimated are of interest, then researchers need to be aware that studies based on large samples will leverage greater weight on the pooled value. Based on systematic reviews of the incidence and prevalence of schizophrenia, we explore if these and related issues are of practical concern. When used with appropriate caution, meta‐analysis can complement the synthesis of frequency data in epidemiology; however, researchers interested in variation should not rely on meta‐analysis alone. Copyright © 2008 John Wiley & Sons, Ltd.
Psychometric properties of the Chinese version of the adult ADHD Self‐report Scale
Authors: Yeh Chin‐Bin , Gau Susan Shur‐Fen , Kessler Ronald C. , Wu Yu‐Yu 
Published: February 2008

AbstractAlthough attention deficit/hyperactivity disorder (ADHD) in adulthood has become a topic of considerable interest to psychiatrists over the past decade, little is known about the prevalence or correlates of adult ADHD in the Chinese population. As a first step in addressing this problem, this study presents data on the psychometric properties of the Chinese version of the World Health Organization's Adult ADHD Self‐report Scale (ASRS) in a sample of 1031 young males from an army base and 3298 young adults from two colleges. All participants completed the Chinese ASRS. Participants from an army base also completed a clinical assessment including the Wender Utah Rating Scale (WURS) for assessing childhood ADHD, the Impulsiveness Scale for measuring the severity of current impulsive behaviors, and information about substance use. Results showed good concordance (intraclass correlations = 0.80∼0.85) and internal consistency (Cronbach's alpha = 0.83∼0.91) among the ASRS subscales and moderate to high correlations between these subscales and the WURS (Pearson's correlations = 0.37∼0.66). The Chinese ASRS also demonstrated the ability to predict childhood disruptive problems and habitual use of substances. Our findings suggest that the Chinese ASRS is a reliable and valid instrument to assist in screening for adult ADHD. Copyright © 2008 John Wiley & Sons, Ltd.
Electrical stimulation increases matrix metalloproteinase‐2 gene expression but does not change its activity in denervated rat muscle
Authors: Russo Thiago Luiz , Peviani Sabrina Messa , Durigan João Luiz Quagliotti , Salvini Tania Fátima 
Published: February 2008

AbstractMuscle‐fiber atrophy occurs concomitantly with intramuscular connective tissue proliferation following denervation. These events contribute to the impairment of mechanical and functional properties of denervated muscles and compromise their recovery. Electrical stimulation (ES) is used in human rehabilitation to treat denervated muscles. However, the effects of this therapy on the intramuscular extracellular matrix (ECM) remain uncertain. Metalloproteinases (MMPs) are responsible by remodeling ECM in many neuromuscular disorders. This study evaluates the effect of ES on the activity of two important MMPs, MMP‐2 and MMP‐9, both involved in ECM remodeling of rat denervated muscles. Thirty‐four Wistar rats (3 months old, 356 ± 38.7 g) were divided into five groups: denervated (D); D+ES; sham denervation; normal (N); and N+ES. Twenty maximal muscle contractions were stimulated every 48 h using surface electrodes, as generally used in the rehabilitation of human denervated muscle. Both zymographic analysis and real‐time polymerase chain reaction (PCR) of MMPs were used to evaluate muscle after denervation for 28 days. Both the D and D+ES groups showed increased MMP‐2 activity compared with the N group (P < 0.05). Furthermore, only the D+ES had increased MMP‐2 gene expression compared with the N group (P < 0.05). MMP‐9 activity was not detected in any of the groups. The results of this study indicate that denervation increases MMP‐2 activity, and ES regulates MMP‐2 gene expression in rat denervated skeletal muscle. These findings clarify the effects of ES on the ECM of denervated muscle and may be helpful in designing new therapeutic strategies for rehabilitation in patients with denervation of muscle. Muscle Nerve, 2008
Convergence analysis of the Q1‐finite element method for elliptic problems with non‐boundary‐fitted meshes
Authors: Ramière Isabelle 
Published: February 2008

AbstractThe aim of this paper is to derive a priori error estimates when the mesh does not fit the original domain's boundary. This problematic of the last century (e.g. the finite difference methodology) returns to topical studies with the huge development of domain embedding, fictitious domain or Cartesian‐grid methods. These methods use regular structured meshes (most often Cartesian) for non‐aligned domains. Although non‐boundary‐fitted approaches become more and more applied, very few studies are devoted to theoretical error estimates.In this paper, the convergence of a Q1‐non‐conforming finite element method is analyzed for second‐order elliptic problems with Dirichlet, Robin or Neumann boundary conditions. The finite element method uses standard Q1‐rectangular finite elements. As the finite element approximate space is not contained in the original solution space, this method is referred to as non‐conforming. A stair‐step boundary defined from the Cartesian mesh approximates the original domain's boundary. The convergence analysis of the finite element method for such a kind of non‐boundary‐fitted stair‐stepped approximation is not treated in the literature. The study of Dirichlet problems is based on similar techniques as those classically used with boundary‐fitted linear triangular finite elements. The estimates obtained for Robin problems are novel and use some more technical arguments.The rate of convergence is proved to be in 𝒪(h1/2) for the H1‐norm for all general boundary conditions, and classical duality arguments allow one to obtain an 𝒪(h) error estimate in the L2‐norm for Dirichlet problems. Numerical results obtained with fictitious domain techniques, which impose original boundary conditions on a non‐boundary‐fitted approximate immersed interface, are presented. These results confirm the theoretical rates of convergence. Copyright © 2008 John Wiley & Sons, Ltd.
Efficient evaluation of the pdf of a random variable through the kernel density maximum entropy approach
Authors: Alibrandi U. , Ricciardi G. 
Published: February 2008

AbstractIn this paper, a new approach for the evaluation of the probability density function (pdf) of a random variable from the knowledge of its lower moments is presented. At first the classical moment problem (MP) is revisited, which gives the conditions such that the assigned sequence of sample moments represent really a sequence of moments of any distribution. Then an alternative approach is presented, termed as the kernel density maximum entropy (MaxEnt) method by the authors, which approximates the target pdf as a convex linear combination of kernel densities, transforming the original MP into a discrete MP, which is solved through a MaxEnt approach. In this way, simply solving a discrete MaxEnt problem, not requiring the evaluation of numerical integrals, an approximating pdf converging toward the MaxEnt pdf is obtained. The method is first demonstrated by approximating some known analytical pdfs (the chi‐square and the Gumbel pdfs) and then it is applied to some experimental engineering problems, namely for modelling the pdf of concrete strength, the circular frequency and the damping ratio of strong ground motions, the extreme wind speed in Messina's Strait region. All the developed numerical applications show the goodness and efficacy of the proposed procedure. Copyright © 2008 John Wiley & Sons, Ltd.