bluuebunny/crossref_metadata_2025 huggingface dataset:
Literal/metafórico: um percurso discursivo
Authors: Furlanetto Maria Marta
Published: December 2010

Neste ensaio discute-se a questão da "primazia" de um dos termos da dicotomia sentido literal/sentido metafórico. Partindo-se de um breve percurso histórico, são considerados alguns pontos relevantes para articular o tema, e examina-se uma tese sobre o funcionamento da metáfora utilizando a abordagem da Análise do Discurso, através da qual se admite que uma variedade de fenômenos converge como produção de metáfora, o que leva à possibilidade de diluição da dicotomia. Nessa direção, a metáfora surge da circulação de bagagem linguístico-discursiva entre as formações discursivas, entendidas como instâncias de formação/repetição/transformação de elementos do saber - componentes de uma memória de discursos -, saber que sofre constante reconfiguração e é levado a incorporar elementos produzidos no exterior de uma formação dada, produzindo efeitos de sentido variados.
Palavras de cristal: sujeito, sentido e versões no processo discursivo de reformulação de livros
Authors: Silva Adriana Pozzani de La Vielle e
Published: December 2010

O campo teórico da Análise do Discurso sustenta a presente discussão sobre o processo discursivo de reformulação de livros. Ao focar o eixo sujeito-sentido-versões - com uma ênfase pontual nos mecanismos sócio-históricos constitutivos do trabalho de autoria -, buscamos explicitar o modo como o acontecimento enunciativo (INDURSKY, 2008), uma vez que é responsável pela emergência da chamada "edição revista", afeta o enunciável próprio a uma dada formação discursiva e reconfigura as redes de memória. O sujeito-autor, tomado na teia das contradições históricas do campo em que se constitui, entra num jogo de repetir-deslocar-esquecer. A reflexão em pauta ganha um matiz a mais quando a identidade polêmica da "edição revista" entra em cena nos encaminhamentos finais.
Correlação entre carta-protesto e histórico de letramento do candidato: uma análise de redações do vestibular
Authors: Silva Elizabeth Maria da , Araújo Denise Lino de
Published: December 2010

Tendo em vista que algumas instituições, a exemplo da Universidade Federal de Campina Grande (UFCG), vêm requisitando, na prova de redação, a escrita de um gênero textual e não mais da dissertação, tradicionalmente solicitada na escola e na maioria dos vestibulares, este artigo objetiva (1) averiguar as práticas letradas requeridas na produção da carta-protesto proposta na prova de redação do vestibular da UFCG 2007 e (2) investigar a correlação entre as práticas demonstradas pelos candidatos na produção da carta e seu histórico de letramento. Para tal, foi realizada uma pesquisa descritivo-interpretativa cujo corpus foi constituído pela prova aplicada no vestibular referido, bem como por uma amostragem de cartas produzidas nesse evento, além de entrevistas realizadas com os candidatos. Os dados, analisados com base nos estudos sobre letramento crítico (BARTON; HAMILTON, 2000; GEE, 2000), indicam que o histórico de letramento dos candidatos parece ser fator decisivo para a mobilização de práticas letradas na redação.
Narrative and figurative self-construction in meaningful stories
Authors: Kupferberg Irit
Published: December 2010

The present study tests the validity of two claims foregrounded in current qualitative studies of troubled talk. First, single story-internal organizing figurative forms constitute succinct versions of troubled narrators' selves. Second, figurative clusters contribute to the construction of narrators' selves when some external or internal obstacle undermines communication. To explore this link between narrative and figurative self-construction, the study espouses a discourse-oriented approach which acknowledges the importance of Conceptual Metaphor Theory as well as a multimethods research design comprising qualitative and quantitative analyses. The analysis of a corpus of 101 meaningful stories produced by young Israeli adults supports the intriguing link between narrative and figurative self-construction.
Climate change effects on an endemic‐rich edaphic flora: resurveying Robert H. Whittaker's Siskiyou sites (Oregon, USA)
Authors: Damschen Ellen I. , Harrison Susan , Grace James B.
Published: December 2010

Species with relatively narrow niches, such as plants restricted (endemic) to particular soils, may be especially vulnerable to extinction under a changing climate due to the enhanced difficulty they face in migrating to suitable new sites. To test for community‐level effects of climate change, and to compare such effects in a highly endemic‐rich flora on unproductive serpentine soils vs. the flora of normal (diorite) soils, in 2007 we resampled as closely as possible 108 sites originally studied by ecologist Robert H. Whittaker from 1949 to 1951 in the Siskiyou Mountains of southern Oregon, USA. We found sharp declines in herb cover and richness on both serpentine and diorite soils. Declines were strongest in species of northern biogeographic affinity, species endemic to the region (in serpentine communities only), and species endemic to serpentine soils. Consistent with climatic warming, herb communities have shifted from 1949–1951 to 2007 to more closely resemble communities found on xeric (warm, dry) south‐facing slopes. The changes found in the Siskiyou herb flora suggest that biotas rich in narrowly distributed endemics may be particularly susceptible to the effects of a warming climate.
Counterintuitive effects of large‐scale predator removal on a midlatitude rodent community
Authors: Maron John L. , Pearson Dean E. , Fletcher Robert J.
Published: December 2010

Historically, small mammals have been focal organisms for studying predator–prey dynamics, principally because of interest in explaining the drivers of the cyclical dynamics exhibited by northern vole, lemming, and hare populations. However, many small‐mammal species occur at relatively low and fairly stable densities at temperate latitudes, and our understanding of how complex predator assemblages influence the abundance and dynamics of these species is surprisingly limited. In an intact grassland ecosystem in western Montana, USA, we examined the abundance and dynamics of Columbian ground squirrels (Spermophilus columbianus), deer mice (Peromyscus maniculatus), and montane voles (Microtus montanus) on 1‐ha plots where we excluded mammalian and avian predators and ungulates, excluded ungulates alone, or allowed predators and ungulates full access. Our goal was to determine whether the relatively low population abundance and moderate population fluctuations of these rodents were due to population suppression by predators. Our predator‐exclusion treatment was divided into two phases: a phase where we excluded all predators except weasels (Mustela spp.; 2002–2005), and a phase where all predators including weasels were excluded (2006–2009). Across the entire duration of the experiment, predator and/or ungulate exclusion had no effect on the abundance or overall dynamics of ground squirrels and deer mice. Ground squirrel survival (the only species abundant enough to accurately estimate survival) was also unaffected by our experimental treatments. Prior to weasel exclusion, predators also had no impacts on montane vole abundance or dynamics. However, after weasel exclusion, vole populations reached greater population peaks, and there was greater recruitment of young animals on predator‐exclusion plots compared to plots open to predators during peak years. These results suggest that the impacts of predators cannot be generalized across all rodents in an assemblage. Furthermore, they suggest that specialist predators can play an important role in suppressing vole abundance even in lower‐latitude vole populations that occur at relatively low densities.
Nitrogen turnover in the leaf litter and fine roots of sugar maple
Authors: Pregitzer Kurt S. , Zak Donald R. , Talhelm Alan F. , Burton Andrew J. , Eikenberry Jennifer R.
Published: December 2010

In order to better understand the nitrogen (N) cycle, a pulse of 15NO3− was applied in 1998 to a sugar maple (Acer saccharum) dominated northern hardwood forest receiving long‐term (1994–2008) simulated atmospheric N deposition. Sugar maple leaf litter and live fine‐root 15N were quantified for four years prior to labeling and for 11 subsequent years. Continuous sampling of 15N following addition of the tracer enabled calculation of leaf litter and fine‐root N pool turnover utilizing an exponential decay function. Fine‐root 15N recovery peaked at 3.7% ± 1.7% the year the tracer was applied, while leaf litter 15N recovery peaked in the two years following tracer application at ∼8%. These results suggest shoots are primarily constructed from N taken up in previous years, while fine roots are constructed from new N. The residence time of N was 6.5 years in leaf litter and 3.1 years in fine roots. The longer residence time and higher recovery rate are evidence that leaves were a stronger sink for labeled N than fine roots, but the relatively short residence time of tracer N in both pools suggests that there is not tight intra‐ecosystem cycling of N in this mature forest.
Evaluation of a Social Marketing Campaign to Support Mexico City's Comprehensive Smoke-Free Law
Authors: Thrasher James F. , Huang Liling , Pérez-Hernández Rosaura , Niederdeppe Jeff , Arillo-Santillán Edna , Alday Jorge
Published: December 2010

Objectives. We aimed to assess the level of awareness and impact of a social marketing campaign to promote Mexico City's 2008 comprehensive smoke-free law.

Methods. Four months after the smoke-free law was implemented but before the campaign launch, we collected data from a population-based, random sample of 961 inhabitants of Mexico City. We analyzed data from 786 respondents who completed follow-up at the end of the campaign to determine campaign exposure and the association between campaign exposure and changes in campaign-targeted knowledge and attitudes.

Results. Recall of any of the 5 campaign materials was 69%, with a uniform distribution of exposure to 1, 2, and 3 or more campaign materials (25%, 25%, and 19%, respectively). Exposure to a greater number of campaign materials was associated in a monotonic relation with campaign-targeted knowledge of ammonia and arsenic in cigarette smoke. In models assessing support for, perceived benefits of, and perceived right to smoke-free places, campaign exposure accounted for a positive change in half of the indicators within each of these domains.

Conclusions. Social marketing campaigns can reinforce knowledge and attitudes that favor smoke-free laws, thereby helping to establish smoke-free norms.
The Shifting Landscape of Health Care: Toward a Model of Health Care Empowerment
Authors: Johnson Mallory O.
Published: December 2010

In a rapidly changing world of health care information access and patients’ rights, there is limited conceptual infrastructure available to understand how people approach and engage in treatment of medical conditions. The construct of health care empowerment is defined as the process and state of being engaged, informed, collaborative, committed, and tolerant of uncertainty regarding health care. I present a model in which health care empowerment is influenced by an interplay of cultural, social, and environmental factors; personal resources; and intrapersonal factors. The model offers a framework to understand patient and provider roles in facilitating health care empowerment and presents opportunities for investigation into the role of health care empowerment in multiple outcomes across populations and settings, including inquiries into the sources and consequences of health disparities.
Socioeconomic Gradients in Chronic Disease Risk Factors in Middle-Income Countries: Evidence of Effect Modification by Urbanicity in Argentina
Authors: Fleischer Nancy L. , Diez Roux Ana V. , Alazraqui Marcio , Spinelli Hugo , De Maio Fernando
Published: December 2010

Objectives. We investigated associations of socioeconomic position (SEP) with chronic disease risk factors, and heterogeneity in this patterning by provincial-level urbanicity in Argentina.

Methods. We used generalized estimating equations to determine the relationship between SEP and body mass index, high blood pressure, diabetes, low physical activity, and eating fruit and vegetables, and examined heterogeneity by urbanicity with nationally representative, cross-sectional survey data from 2005. All estimates were age adjusted and gender stratified.

Results. Among men living in less urban areas, higher education was either not associated with the risk factors or associated adversely. In more urban areas, higher education was associated with better risk factor profiles (P < .05 for 4 of 5 risk factors). Among women, higher education was associated with better risk factor profiles in all areas and more strongly in more urban than in less urban areas (P < 0.05 for 3 risk factors). Diet (in men) and physical activity (in men and women) were exceptions to this trend.

Conclusions. These results provide evidence for the increased burden of chronic disease risk among those of lower SEP, especially in urban areas.
Uncovering Tensions and Capitalizing on Synergies in HIV/AIDS and Antiviolence Programs
Authors: Dworkin Shari L. , Dunbar Megan S. , Krishnan Suneeta , Hatcher Abigail M. , Sawires Sharif
Published: December 2010

Research frequently points to the need to empower women to effectively combat the twin epidemics of HIV/AIDS and gender-based violence. Simultaneously, there has been increased attention given to working with men in gender equality efforts. The latter approach intervenes on masculinities as part of the fight against HIV/AIDS and violence. No research has considered these 2 lines of work side by side to address several important questions: What are the points of overlap, and the tensions and contradictions between these 2 approaches? What are the limitations and unintended consequences of each? We analyzed these 2 parallel research trends and made suggestions for how to capitalize on the synergies that come from bolstering each position with the strengths of the other.
The Effect of Tobacco Outlet Density and Proximity on Smoking Cessation
Authors: Reitzel Lorraine R. , Cromley Ellen K. , Li Yisheng , Cao Yumei , Dela Mater Richard , Mazas Carlos A. , Cofta-Woerpel Ludmila , Cinciripini Paul M. , Wetter David W.
Published: December 2010

Objectives. We examined the influence of tobacco outlet density and residential proximity to tobacco outlets on continuous smoking abstinence 6 months after a quit attempt.

Methods. We used continuation ratio logit models to examine the relationships of tobacco outlet density and tobacco outlet proximity with biochemically verified continuous abstinence across weeks 1, 2, 4, and 26 after quitting among 414 adult smokers from Houston, Texas (33% non-Latino White, 34% non-Latino Black, and 33% Latino). Analyses controlled for age, race/ethnicity, partner status, education, gender, employment status, prequit smoking rate, and the number of years smoked.

Results. Residential proximity to tobacco outlets, but not tobacco outlet density, provided unique information in the prediction of long-term, continuous abstinence from smoking during a specific quit attempt. Participants residing less than 250 meters (P = .01) or less than 500 meters (P = .04) from the closest tobacco outlet were less likely to be abstinent than were those living 250 meters or farther or 500 meters or farther, respectively, from outlets.

Conclusions. Because residential proximity to tobacco outlets influences smoking cessation, zoning restrictions to limit tobacco sales in residential areas may complement existing efforts to reduce tobacco use.
Parental Eligibility and Enrollment in State Children's Health Insurance Program: The Roles of Parental Health, Employment, and Family Structure
Authors: Miller Jane E. , Gaboda Dorothy , Nugent Colleen N. , Simpson Theresa M. , Cantor Joel C.
Published: December 2010

We examined eligibility and enrollment among parents of children in New Jersey's State Children's Health Insurance Program following expansion of parental eligibility for NJ FamilyCare coverage. Data were from the 2003 NJ FamilyCare Family Health Survey (n = 416 families). Parental eligibility was higher in households without a full-time employed parent (odds ratio [OR] = 5.50; 95% confidence interval [CI] = 2.72, 11.14) and lower among single parents (OR = 0.38; 95% CI = 0.23, 0.61). Enrollment was higher among single parents (OR = 2.24; 95% CI = 1.17, 4.31). Roughly one third of eligible parents did not enroll, suggesting the need to increase awareness of parental eligibility and reduce barriers to enrollment.
Sclerostin and Dickkopf-1 in Renal Osteodystrophy
Authors: Cejka Daniel , Herberth Johann , Branscum Adam J. , Fardo David W. , Monier-Faugere Marie-Claude , Diarra Danielle , Haas Martin , Malluche Hartmut H.
Published: December 2010

Background and objectives

The serum proteins sclerostin and Dickkopf-1 (Dkk-1) are soluble inhibitors of canonical wnt signaling and were recently identified as components of parathyroid hormone (PTH) signal transduction. This study investigated the associations between sclerostin and Dkk-1 with histomorphometric parameters of bone turnover, mineralization, and volume in stage 5 chronic kidney disease patients on dialysis (CKD-5D).

Design, setting, participants, & measurements

In a cross-sectional study, 60 CKD-5D patients underwent bone biopsies followed by histomorphometry. Levels of sclerostin, Dkk-1, and intact PTH (iPTH) were determined in blood.

Results

Serum levels of sclerostin and iPTH correlated negatively. In unadjusted analyses, sclerostin correlated negatively with histomorphometric parameters of turnover, osteoblastic number, and function. In adjusted analyses, sclerostin remained a strong predictor of parameters of bone turnover and osteoblast number. An observed correlation between sclerostin and cancellous bone volume was lost in regression analyses. Sclerostin was superior to iPTH for the positive prediction of high bone turnover and number of osteoblasts. In contrast, iPTH was superior to sclerostin for the negative prediction for high bone turnover and had similar predictive values than sclerostin for the number of osteoblasts. Serum levels of Dkk-1 did not correlate with iPTH or with any histomorphometric parameter.

Conclusions

Our data describe a promising role for serum measurements of sclerostin in addition to iPTH in the diagnosis of high bone turnover in CKD-5D patients, whereas measurements of Dkk-1 do not seem to be useful for this purpose.
Cardiorespiratory Fitness Is Independently Associated with 25-Hydroxyvitamin D in Chronic Kidney Disease
Authors: Petchey William G. , Howden Erin J. , Johnson David W. , Hawley Carmel M. , Marwick Thomas , Isbel Nicole M.
Published: December 2010

Background and objectives

Vitamin D is an established important contributor to muscle function and aerobic metabolism. Hypovitaminosis D is highly prevalent in CKD patients and is associated with increased cardiovascular (CV) mortality via unknown mechanisms. Because aerobic-exercise capacity strongly predicts future CV events, we hypothesized that vitamin D status could be linked to CV outcomes via an effect on maximum aerobic-exercise capacity in patients with CKD and that this effect may be mediated in part via its actions on muscle strength and functional ability.

Design, setting, participants, & measurements

Baseline demographic, anthropometric, and biochemical data were collected in a cross-sectional study of patients with moderate CKD. Peak aerobic capacity was determined during treadmill stress testing using metabolic equivalence of tasks. Physical activity was assessed using the Active Australia questionnaire, grip strength by dynamometer, and functional capacity by “Up & Go” testing.

Results

The study included 85 participants (age 59.5 ± 9.7 years, 60% male, 44% diabetic, 92% Caucasian; mean serum 25-hydroxyvitamin D [25-OHD] 78.4 ± 29.4 nmol/L). We demonstrated that 25-OHD status was independently associated with aerobic-exercise capacity (β = 0.2; P = 0.008). Aerobic-exercise capacity was also predicted by younger age, white race, smaller waist circumference, absence of a previous angina history, and increasing weekly physical activity. However, neither muscle strength nor functional ability were significantly associated with 25-OHD.

Conclusions

Vitamin D is independently associated with aerobic capacity in CKD patients, and this finding is not explained by changes in muscle strength or functional ability.
Squirrel-cage motor drive dynamics modeling including chosen damages - programming tools
Authors: Sołbut Adam
Published: December 2010

Squirrel-cage motor drive dynamics modeling including chosen damages - programming tools

Description of program tools simplifying simulation applications building for physical phenomenons described by differential equations in state equations form modeling is presented in the paper. A method for using prepared libraries for squirrel-cage motors including any motor damages modeling had been described. For that purpose, squirrel-cage motor mathematical model in natural coordinates system had been presented. Presented solutions provide also supply sources (inverters) modeling, including their microprocessor implementation and other phenomenons, that assume state equation structure step changes, depending on variable limitations and time value.
Corona current concept in lightning return-stroke models of engineering type
Authors: Masłowski Grzegorz
Published: December 2010

Corona current concept in lightning return-stroke models of engineering type

A role of radial corona current in a lightning discharge is discussed in the paper. It is shown that the corona current concept previously introduced by Cooray for lightning return stroke models of distributed-current-source (DCS) type, and later, by Maslowski and Rakov for lumped-current-source (LCS) type models enables to show duality between these two types of models. Further, it is demonstrated that the corona current is useful during consideration of dynamics of the lightning-channel corona sheath. As an example of application of presented approach a relaxation model of charge motion in the corona sheath is analysed together with plots which show the rate of expansion and shrinkage of the lightning corona sheath on both microsecond and millisecond time scales.
Robustness of adaptive discrete-time LQG control for first-order systems
Authors: Królikowski A. , Horla D.
Published: December 2010

Robustness of adaptive discrete-time LQG control for first-order systems

The discrete-time adaptive LQG control of first-order systems is considered from robustness point of view. Both stability and performance robustness are analyzed for different control system structures. A case of amplitude-constrained control is presented, and application of certainty equivalence for self-tuning implementation is also discussed.
Information geometry of divergence functions
Authors: Amari S. , Cichocki A.
Published: December 2010

Information geometry of divergence functions

Measures of divergence between two points play a key role in many engineering problems. One such measure is a distance function, but there are many important measures which do not satisfy the properties of the distance. The Bregman divergence, Kullback-Leibler divergence andf-divergence are such measures. In the present article, we study the differential-geometrical structure of a manifold induced by a divergence function. It consists of a Riemannian metric, and a pair of dually coupled affine connections, which are studied in information geometry. The class of Bregman divergences are characterized by a dually flat structure, which is originated from the Legendre duality. A dually flat space admits a generalized Pythagorean theorem. The class off-divergences, defined on a manifold of probability distributions, is characterized by information monotonicity, and the Kullback-Leibler divergence belongs to the intersection of both classes. Thef-divergence always gives the α-geometry, which consists of the Fisher information metric and a dual pair of ±α-connections. The α-divergence is a special class off-divergences. This is unique, sitting at the intersection of thef-divergence and Bregman divergence classes in a manifold of positive measures. The geometry derived from the Tsallisq-entropy and related divergences are also addressed.
Towards human consistent data driven decision support systems using verbalization of data mining results via linguistic data summaries
Authors: Kacprzyk J. , Zadrożny S.
Published: December 2010

Towards human consistent data driven decision support systems using verbalization of data mining results via linguistic data summaries

We present how the conceptually and numerically simple concept of a fuzzy linguistic database summary can be a very powerful tool for gaining much insight into the essence of data that may be relevant for a business activity. The use of linguistic summaries provides tools for the verbalization of data analysis (mining) results which, in addition to the more commonly used visualization e.g. via a GUI, graphical user interface, can contribute to an increased human consistency and ease of use. The results (knowledge) derived are in a simple, easily comprehensible linguistic form which can be effectively and efficiently employed for supporting decision makers via the data driven decision support system paradigm. Two new relevant aspects of the analysis are also outlined which was first initiated by the authors. First, following Kacprzyk and Zadrożny [1] comments are given on an extremely relevant aspect of scalability of linguistic summarization of data, using their new concept of a conceptual scalability that is crucial for large applications. Second, following Kacprzyk and Zadrożny [2] it is further considered how linguistic data summarization is closely related to some types of solutions used in natural language generation (NLG), which can make it possible to use more and more effective and efficient tools and techniques developed in this another rapidly developing area. An application of a computer retailer is outlined.
TuLiPA - Parsing extensions of TAG with range concatenation grammars
Authors: Kallmeyer L. , Maier W. , Parmentier Y. , Dellert J.
Published: December 2010

TuLiPA - Parsing extensions of TAG with range concatenation grammars

In this paper we present a parsing framework for extensions of Tree Adjoining Grammar (TAG) called TuLiPA (Tübingen Linguistic Parsing Architecture). In particular, besides TAG, the parser can process Tree-Tuple MCTAG with Shared Nodes (TT-MCTAG), a TAG-extension which has been proposed to deal with scrambling in free word order languages such as German. The central strategy of the parser is such that the incoming TT-MCTAG (or TAG) is transformed into an equivalent Range Concatenation Grammar (RCG) which, in turn, is then used for parsing. The RCG parser is an incremental Earley-style chart parser. In addition to the syntactic anlysis, TuLiPA computes also an underspecified semantic analysis for grammars that are equipped with semantic representations.
The art and science of large-scale disasters
Authors: Gad-El-Hak M.
Published: December 2010

The art and science of large-scale disasters

The subject of large-scale disasters is broadly introduced in this article. Both the art and science of predicting, preventing and mitigating natural and manmade disasters are discussed. A universal, quantitative metric that puts all natural and manmade disasters on a common scale is proposed. Issues of prediction, control and mitigation of catastrophes are presented. The laws of nature govern the evolution of any disaster. In some cases, as for example weather-related disasters, the first-principles laws of classical mechanics could be written in the form of field equations, but exact solutions of these often nonlinear differential equations are impossible to obtain particularly for turbulent flows, and heuristic models together with intensive use of supercomputers are necessary to proceed to a reasonably accurate forecast. In other cases, as for example earthquakes, the precise laws are not even known and prediction becomes more or less a black art. Management of any type of disaster is more art than science. Nevertheless, much can be done to alleviate the resulting pain and suffering. The expansive presentation of the broad field of large-scale disasters precludes a detailed coverage of any one of the many topics touched upon. Three take-home messages are conveyed, however: a universal metric for all natural and manmade disasters is presented; all facets of the genre are described; and a proposal is made to view all disasters as dynamical systems governed for the most part by the laws of classical mechanics.
A new scheme for power factor correction and active filtering for six-pulse converters loads
Authors: Han Y. , Khan M. , Xu L. , Yao G. , Zhou L. , Chen C.
Published: December 2010

A new scheme for power factor correction and active filtering for six-pulse converters loads

This paper presents a novel harmonic-free power factor correction (PFC) topology based on T-type active power filter (APF), which is dedicated for power factor improvement and harmonic filtering for six-pulse converter loads. The cascaded controller structure is adopted for the proposed system, namely, the inner current loop and outer voltage loop. The current-loop control scheme is based on a decoupled state-space equations of the T-type APF using separate proportional-integral (PI) controllers in d-axis and q-axis of the synchronous rotating reference frame (SRRF) synchronized with grid voltages, respectively. The fundamental components of load-side currents are feed forwarded in the current-loop using two groups of synchronous frame adaptive linear neural networks (ADALINEs) to ensure estimation accuracy and a fast dynamic response. A separate proportional-integral (PI) controller is adopted in the outer voltage loop for balancing the active power flow of the voltage source inverter (VSI) dc-side capacitor. The experimental results confirm well with the theoretical analysis.
Multi-objective decision making and search space for the evaluation of production process scheduling
Authors: Witkowski T. , Antczak P. , Antczak A.
Published: December 2010

Multi-objective decision making and search space for the evaluation of production process scheduling

Over the years, various approaches have been proposed in order to solve the multi-objective job-shop scheduling problem - particularly a hard combinatorial optimization problem. The paper presents an evaluation of job shop scheduling problem under multiple objectives (mean flow time, max lateness, mean tardiness, mean weighted tardiness, mean earliness, mean weighted earliness, number of tardy tasks). The formulation of the scheduling problem has been presented as well as the evaluation schedules for various optimality criteria. The paper describes the basic mataheuristics used for optimization schedules and the approaches that use domination method, fuzzy method, and analytic hierarchy proccess (AHP) for comparing schedules in accordance with multiple objectives. The effectiveness of the algorithms has been tested on several examples and the results have been shown. New search space for evaluation and generation of schedules has been created. The three-dimensional space can be used for the analysis and control of the production processes.
Repairable systems availability optimization under imperfect maintenance
Authors: Samet S. , Chelbi A. , Hmida F.
Published: December 2010

Repairable systems availability optimization under imperfect maintenance

This paper deals with the modeling of a preventive maintenance strategy applied to a single-unit system subject to random failures. According to this policy, the system is subjected to imperfect periodic preventive maintenance restoring it to ‘as good as new’ with probability p and leaving it at state ‘as bad as old’ with probability q. Imperfect repairs are performed following failures occurring between consecutive preventive maintenance actions, i.e the times between failures follow a decreasing quasi-renewal process with parametera. Considering the average durations of the preventive and corrective maintenance actions as well as their respective efficiency extents, a mathematical model is developed in order to study the evolution of the system stationary availability and determine the optimal PM period which maximizes it. The modeling of the imperfection of the corrective maintenance actions requires the knowledge of the quasi-renewal function. A new expression approximating this function is proposed for systems whose times to first failure follow a Gamma distribution. Numerical results are obtained and discussed.
Power electronic converter for photovoltaic systems with the use of FPGA-based real-time modeling of single phase grid-connected systems
Authors: Piróg S. , Stala R. , Stawiarski Ł.
Published: December 2010

Power electronic converter for photovoltaic systems with the use of FPGA-based real-time modeling of single phase grid-connected systems

The paper presents a method of investigation of grid connected systems with a renewable energy source. The method enables fast prototyping of control systems and power converters components by real-time simulation of the system. Components of the system such as energy source (PV array), converters, filters, sensors and control algorithms are modeled in FPGA IC. Testing the systems before its practical application reduces cost and time-to-market. FPGA devices are commonly used for digital control. The resources of the FPGAs used for preliminary testing can be sufficient for the complete system modelling. Debugging tools for FPGA enable observation of many signals of the analyzed power system (as a result of the control), with very advanced triggering tools. The presented method of simulation with the use of hardware model of the power system in comparison to classical simulation tools gives better possibilities for verification of control algorithms such as MPPT or anti-islanding.
Single phase full bridge inverter with coupled filter inductors and voltage doubler for PV module integrated converter system
Authors: Jiang Y. , Pan J.
Published: December 2010

Single phase full bridge inverter with coupled filter inductors and voltage doubler for PV module integrated converter system

This paper presents a single phase full bridge inverter with coupled filter inductors and voltage doubler for PV module integrated converter (MIC) system. In DC/DC stage, full bridge circuit with high frequency sinusoidal pulse width modulation control is used, and high frequency transformer with voltage doubler rectifier circuit to increase conversional ratio is adopted. Finally, at the conversion end the rectified sinusoidal waveforms is generated. The coupled filter inductors, which are placed in voltage doubler, not only reduce circulating current, which increases efficiency but also make the rectified output sinusoidal waveforms of DC/DC stage as smooth voltage source. In DC/AC stage, the full bridge circuit with line frequency square wave control is adopted to reduce switching losses and control cost. To verify the presented analysis a 100 W prototype single phase 220 VAC 50 Hz inverter output has been constructed and the experimental results are given.
Selected conducted electromagnetic interference issues in distributed power systems
Authors: Smoleński R.
Published: December 2010

Selected conducted electromagnetic interference issues in distributed power systems

This paper addresses the specific issues associated with electromagnetic compatibility that should be taken into account at the developmental stage of distributed systems. The main aim is to establish how far conducted interferences can penetrate the electric grid and how the group of converters, which individually meet EMC standards, influence the mains supply. The measured results of the spread of electromagnetic interference (EMI) current over a typical local electric grid and the low and medium voltage side of the power transformer are presented. The commonly applied, in distributed power systems, four-quadrant converter has been used as a test interference source. The limitations in the applicability of standardized methods for evaluation of aggregated conducted interferences have been presented in a system consisting of a group of two-quadrant frequency converter drives.
Control of PWM rectifier under grid voltage dips
Authors: Bobrowska-Rafał M. , Rafał K. , Abad G. , Jasiński M.
Published: December 2010

Control of PWM rectifier under grid voltage dips

This paper investigates control structure for grid connected three-phase two-level Voltage Source Converter (VSC) under distorted grid voltage conditions. Grid voltage is distorted by balanced and unbalanced voltage dips and higher harmonics. To address the problem, the control structure of converter is presented. The control system is a modification of Voltage Oriented Control (VOC) based on Dual Vector Current Controllers (DVCC). Grid synchronization under distorted voltage is achieved by employing Phase Locked Loop (PLL). Simulation and experimental results, which illustrate properties of proposed system, are presented.
Atomic mobilities and diffusivities in the fcc, L12and B2 phases of the Ni-Al system
Authors: Zhang Lijun , Du Yong , Chen Qing , Steinbach Ingo , Huang Baiyun
Published: December 2010

A phenomenological model was utilized to describe diffusivities in the γ (fcc) /γü (L12) and A2/B2 phases of the NiüAl system. An effective strategy, which takes the homogeneity range and defect concentration into account, was developed in the present work to optimize the atomic mobilities of γü phase. Such a strategy results in a dramatic decrease in the number of atomic mobility parameters to be evaluated for the L12phase. The measured composition- and temperature- dependent diffusivities in the NiüAl system have been well replicated by the present mobility descriptions. For the L12phase, comprehensive comparisons show that with fewer model parameters the presently obtained mobilities yield a better fit to experimental diffusivities, compared with previous assessments. The mobility descriptions are further validated by comparing calculated and measured concentration profiles for various diffusion couples. The time-dependent Al composition profile for the annealed vapor Al / γ couple is accurately described for the first time.
Effect of grain boundary precipitates on vibration damping of FeüCrüMgüAl/Si alloy
Authors: Girish B. M. , Satish B. M. , Mahesh K.
Published: December 2010

The damping capacity of three different FeüCrüMgüAl/Si alloys was measured using the conventional cantilever beam method. The samples were heat-treated in vacuum at 1100°C for 1 h followed by slow cooling (120°C hü1). The vibration damping capacity of the alloys was definitely influenced by the amount of grain boundary precipitates as well as by the chromium concentration in the precipitates. The three different alloys investigated were FeüCrüMgüAl, FeüCrüMgüSi, and FeüCrüMgüAlüSi. It was found that the FeüCrüMgüAlüSi alloy exhibits the highest damping capacity with the smallest amount of grain boundary precipitates and least chromium concentration. Among the remaining alloys, although the chromium concentrations in the grain boundary precipitates were almost the same, the amount of grain boundary precipitates in FeüCrüMgüAl was lower than in FeüCrüMgüSi, and hence the damping capacity of FeüCrüMgüAl was higher than the other.
Study of the influence of UV-irradiation on the photodegradation of plasticized poly(para-tert-butylstyrene) films
Authors: Ani Khalid E. Al , Ramadhan Afrah E.
Published: December 2010

The photodegradation of thin films of poly(para-tert-butylstyrene) with 265 nm radiation in the presence of oxygen, and as a function of irradiation time, has been studied using fluorescence, Fourier transform-infrared spectroscopy, and ultraviolet-visible spectroscopy. The influence of phthalate and terephthalate plasticizers on photo-oxidative degradation was also investigated. Blending with phthalate plasticizers was found to cause a higher efficiency of degradation than that obtained for doping with terephthalate plasticizers. The intensity of absorption was also found to increase with time of irradiation and in the intensity of a new absorption band at longer wavelength, thus indicating a possibility of photodegradation of polymer films. The analysis of the Fourier transform-infrared spectra of the irradiated and non-irradiated samples showed an increase in the intensities of the carbonyl and hydroxyl regions of the Fourier transform-infrared spectra providing evidence for the photodegradation as well as the photo-oxidation of polymeric chains. The increase in the analyzed ranges is attributed to the formation of alcohols, aliphatic ketones and to the increase in the number of polyene structures that resulted from hydrogen abstraction during photodegradation reactions.
Time resolved X-ray imaging of eutectic cellular patterns evolving during solidification of ternary Al–Cu–Ag alloys
Authors: Zimmermann Gerhard , Hecht Ulrike , Mathes Michael , Mathiesen Ragnvald H.
Published: December 2010

Synchrotron radiography has enabled time and space resolved investigation of directional solidification of ternary AlüCuüAg eutectic. Due to a high spatial resolution the lamellar spacing of the eutectic can be identified. The morphological instability of a planar eutectic solidüliquid interface towards eutectic cells observed in sheet-like samples is investigated for different solidification conditions. The results are summarized in a stability diagram and compared to findings in bulk samples and theoretical predictions based on the criterion of constitutional undercooling. During growth of eutectic cells an intriguing dual phase fragmentation in the intercolumnar/cellular regions with Al2Cu fragments settling and Al-rich fragments rising in the melt was observed, which may be unique for coupled growth of multicomponent eutectics.
Enhanced photocatalytic activity of beryllium doped titania in visible light on the degradation of methyl orange dye
Authors: Avasarala Balaram Kiran , Tirukkovalluri Siva Rao , Bojja Sreedhar
Published: December 2010

The present work is focused on the synthesis of beryllium doped titania (Be+2–TiO2) at different percentages (0.25, 0.5, 0.75 and 1.0 wt.%) by the sol-gel method and its characterization using X-ray diffraction, X-ray photoelectron spectroscopy, Fourier transform-Infra red and Ultra violet-visible absorption spectroscopic methods. Diffraction peaks of anatase crystalline phase were present in both synthesized TiO2 and Be+2–TiO2. The presence of Be+2 ion in the TiO2 structure caused a significant absorption shift towards the visible region and its presence was confirmed by X-ray photoelectron spectroscopy and Fourier Transform-Infra Red data. The photocatalytic efficiency of the synthesized Be+2–TiO2 and pure TiO2 was evaluated by the degradation of aqueous methyl orange dye under visible light irradiation, where the degradation rate of methyl orange by Be+2–TiO2 was found to be higher than by pure TiO2. This can be attributed to more efficient electron–hole creation in Be+2–TiO2 in visible light and the electrons produced due to photosensitization of the dye can be scavenged by photoexcited doped TiO2 in visible light.
Portable head CT scan and its effect on intracranial pressure, cerebral perfusion pressure, and brain oxygen
Authors: Peace Kaitlin , Maloney-Wilensky Eileen , Frangos Suzanne , Hujcs Marianne , Levine Joshua , Kofke W. Andrew , Yang Wei , Le Roux Peter D.
Published: December 2010

Object

Follow-up head CT scans are important in neurocritical care but involve intrahospital transport that may be associated with potential hazards including a deleterious effect on brain tissue oxygen pressure (PbtO2). Portable head CT (pHCT) scans offer an alternative imaging technique without a need for patient transport. In this study, the investigators examined the effects of pHCT scans on intracranial pressure (ICP), cerebral perfusion pressure (CPP), and PbtO2 in patients with severe brain injury.

Methods

Fifty-seven pHCT scans were obtained in 34 patients (mean age of 42 ± 15 years) who underwent continuous ICP, CPP, and PbtO2 monitoring in the neuro intensive care unit at a university-based Level I trauma center. Patient ICU records were retrospectively reviewed and physiological data obtained during the 3 hours before and after pHCT scans were examined.

Results

Before pHCT, the mean ICP and CPP were 14.3 ± 7.4 and 78.9 ± 20.2 mm Hg, respectively. Portable HCT had little effect on ICP (mean ICP 14.1 ± 6.6 mm Hg, p = 0.84) and CPP (mean CPP 81.0 ± 19.8 mm Hg, p = 0.59). The mean PbtO2 was similar before and after pHCT (33.2 ± 17.0 mm Hg and 31.6 ± 15.9 mm Hg, respectively; p = 0.6). Ten episodes of brain hypoxia (PbtO2 < 15 mm Hg) were observed before pHCT; these episodes prompted scans. Brain hypoxia persisted in 5 patients after pHCT despite treatment. No new episodes of brain hypoxia were observed during or after pHCT.

Conclusions

These data suggest that pHCT scans do not have a detectable effect on a critically ill patient's ICP, CPP, or PbtO2.
Hearing preservation in the resection of vestibular schwannomas: patterns of hearing preservation and patient-assessed hearing function
Authors: Wind Joshua J. , Leonetti John P. , Raffin Michael J. M. , Pisansky Marc T. , Herr Brian , Triemstra Justin D. , Anderson Douglas E.
Published: December 2010

Object

No extant literature documents the analysis of patient perceptions of hearing as a corollary to objective audiometric measures in patients with vestibular schwannoma (VS), or acoustic neuroma. Therefore, using objective audiometric data and patient perceptions of hearing function as outlined on a questionnaire, the authors evaluated the hearing of patients who underwent VS resection.

Methods

This investigation involved a retrospective review of 176 patients who had undergone VS resections in which hearing preservation was a goal. Both pre- and postoperative audiometry, expressed as a speech discrimination score (SDS) and pure tone threshold average (PTA), were performed, and the results were analyzed. Intraoperative auditory brainstem responses were also recorded. Eighty-seven of the patients (49.4%) completed a postoperative questionnaire designed to assess hearing function in a variety of social and auditory situations. Multiple linear regression analyses were completed to compare available audiometric results with questionnaire responses for each patient.

Results

One hundred forty-two patients (80.7%) had PTA and SDS audiometric data pertaining to the surgically treated ear; 94 of these patients (66.2%) had measurable postoperative hearing, as defined by a PTA < 120 dB or SD > 0%. Eighty-seven patients (49.4%) completed the retrospective questionnaire, and 74 of them had complete audiometric data and thus were included in a comparative analysis. Questionnaire data showed major postoperative subjective hearing decrements, even among patients with the same pre- and postoperative objective audiometric hearing status. Moreover, the subscore reflecting hearing while exposed to background noise, or the “cocktail party effect,” characterized the most significant patient-perceived hearing deficit following VS resection.

Conclusions

The authors' analysis of a patient-perceived hearing questionnaire showed that hearing during exposure to background noise, or the cocktail party effect, represents a significant postoperative hearing deficit and that patient perception of this deficit has a strong relation with audiometric data. Furthermore, questionnaire responses revealed a significant disparity between subjective hearing function and standard audiometrics such that even with similar levels of audiometric data, subjective measures of hearing, especially the cocktail party effect, decreased postoperatively. The authors posit that the incorporation of patient-perceived hearing function evaluation along with standard audiometry is an illustrative means of identifying subjective hearing deficits after VS resection and may ultimately aid in specific and subsequent treatment for these patients.