bluuebunny/crossref_metadata_2025 huggingface dataset:
Merchants and councilors: intellectual divergences in early 17th century British economic thought
Authors: Suprinyak Carlos Eduardo
Published: May 2012

During the early 1620's, England went through a period of intense economic disorders which sparked the interest of many in economic reasoning. The decade witnessed the emergence of the most relevant pieces of economic literature of the early Stuart era, but the debate was not restricted to the abstract confrontation of economic writers. The fundamental issue at stake in the controversies between Malynes, Misselden, and Mun - the integration of money and international trade in a coherent explanation of economic phenomena - was also the subject of much care in the public sphere at large. The parliamentary session of 1621, in particular, put in evidence not only the fundamental relevance of the matter for understanding England's economic maladies, but also the great difficulties involved in its investigation. By bringing all these elements together, this paper seeks to articulate a more dense and meaningful portrait of the prevailing state of economic ideas in early 17th century England.
Germinação e vigor de sementes de Sapindus saponaria L. submetidas a tratamentos pré-germinativos, temperaturas e substratos
Authors: Oliveira Lucicléia Mendes de , Bruno Riselane de Lucena Alcântara , Silva Katiane da Rosa Gomes da , Silva Valério Damásio da Mota , Ferarri Cibele dos Santos , Silva Givanildo Zildo da
Published: May 2012

Sapindus saponaria L. é uma árvore de grande porte distribuída especialmente na região Amazônica, sendo de grande importância para o reflorestamento de áreas degradadas, na construção civil e confecção de brinquedos. O objetivo dessa pesquisa foi testar tratamentos pré-germinativos para superar a dormência e avaliar o efeito da temperatura e do substrato na germinação das sementes de S. saponaria. O experimento foi conduzido em ambiente protegido e no Laboratório de Análise de Sementes (LAS) da Universidade Federal da Paraíba. Dois ensaios foram desenvolvidos, sendo no primeiro testados os seguintes tratamentos: imersão das sementes em ácido sulfúrico (H2SO4) por 0, 15, 30, 45 e 60 minutos, analisando-se as variáveis: emergência e índice de velocidade de emergência, comprimento e massa seca de plântulas. No segundo ensaio foi avaliado o efeito das temperaturas (25, 20-30, 30 e 35°C) e substratos (areia, vermiculita e pó-de-coco) na germinação e no vigor das sementes. Pelos resultados constata-se que a imersão das sementes de S. saponaria em ácido sulfúrico por 60 minutos é suficiente para superar a dormência acelerando e uniformizando a emergência das plântulas. A melhor condição para executar o teste de germinação é empregando temperatura constante de 30°C ou alternada de 20-30°C em substrato vermiculita ou apenas 30°C combinado com o substrato areia.
Efeitos do treinamento físico durante a gestação sobre a evolução ponderal, glicemia e colesterolemia de ratos adultos submetidos à desnutrição perinatal
Authors: Falcão-Tebas Filippe , Tobias Amanda Thereza , Bento-Santos Adriano , Santos José Antônio dos , Vasconcelos Diogo Antônio Alves de , Fidalgo Marco Antônio , Manhães-de-Castro Raul , Leandro Carol Góis
Published: May 2012

A incompatibilidade entre a desnutrição perinatal e uma nutrição adequada durante o desenvolvimento aumenta o risco de aparecimento precoce de doenças não transmissíveis na vida adulta. Todavia, acredita-se que a atividade física materna possa atenuar estas consequências. O presente estudo teve como objetivo avaliar os efeitos do treinamento físico durante a gestação na evolução ponderal, circunferência abdominal, glicemia e colesterolemia de filhotes adultos submetidos à desnutrição perinatal. Ratas Wistar (n = 12) foram divididas em quatro grupos: controle (C, n = 3), treinada (T, n = 3), desnutrida (D, n = 3) e treinada desnutrida (T+D, n = 3). Durante a gestação e lactação, os grupos D e T+D receberam dieta baixa em proteína (8% caseína) e os grupos C e T receberam dieta normoproteica (caseína a 17%). O protocolo de treinamento físico moderado foi realizado em esteira ergométrica (cinco dias/semana, 60 min/dia, a 65% do VO2max) e iniciou quatro semanas antes da gestação. Na gestação, a duração e a intensidade do treinamento foram reduzidas (cinco dias/semana, 20 min/dia, a 30% do VO2max) até o 19º dia pré-natal. Após o desmame, os filhotes (C F = 9, T F = 9, D F = 7, T+D F = 9) receberam dieta padrão de biotério e foram avaliados aos 270 dias de idade. A circunferência abdominal (CA) foi avaliada relativa ao peso corporal. Para avaliação da glicemia e colesterolemia foi utilizado o método enzimático colorimétrico da glicose-oxidase/peroxidase e da colesterol-oxidase, respectivamente. Ratos do grupo D F apresentaram um maior ganho de peso corporal ao longo do crescimento, maiores valores de CA, glicemia e colesterolemia quando comparados ao grupo C F. Para o grupo T+D F, o ganho de peso foi atenuado, e a CA, a glicemia e a colesterolemia foram normalizadas (p < 0,05). Esses resultados demonstram que o treinamento físico durante a gestação atenua os efeitos da desnutrição perinatal sobre alguns indicadores murinométricos e bioquímicos nos filhotes adultos.
Sobre cadeias de gêneros
Authors: Nobre Kennedy Cabral , Biasi-Rodrigues Bernardete
Published: May 2012

Neste ensaio discutimos sobre cadeias de gênero, um agrupamento específico de gêneros discursivos caracterizado pela passagem sistemática e necessária de um gênero a outro(s). Baseados na Sociorretórica de Swales (2004) e na Análise Crítica do Discurso de Fairclough (2001a; 2003), buscamos critérios para caracterização de uma cadeia de gêneros, bem como critérios para sua classificação. Propomos considerar dois tipos específicos de encadeamento genérico: um simples, em que os gêneros todos são produzidos num único domínio institucional; e um complexificado, quando outros domínios institucionais ramificam-se de uma cadeia de gêneros simples preexistente.
Por uma rediscussão do conceito de intergenericidade
Authors: Lima-Neto Vicente de , Araújo Júlio César
Published: May 2012

Este ensaio tem como objetivo rediscutir a intergenericidade, conceito que estuda as misturas de gêneros. Com base nas reflexões de Bakhtin (2006 [1953]) sobre reelaborações e misturas de gêneros, buscamos argumentos que sustentem a tese de que o conceito de intergenericidade, tal qual vem sendo proposto pela Linguística de Texto, não contempla todas as diferentes formas de manifestação textual em que se misturam gêneros. Propomos três tipos de mesclas genéricas distintas: a mescla por intergenericidade prototípica, caracterizada pela fusão de traços de pelo menos dois gêneros; a mescla por gêneros casualmente ocorrentes; constituída por gêneros que não necessariamente se fundem, mas que coexistem numa relação simbiótica, voltada para um propósito comunicativo comum; e a mescla por gêneros intercalados, que envolve gêneros que podem pertencer a cenas enunciativas distintas.
Shared Decision-Making in Pediatric Allogeneic Blood and Marrow Transplantation: What If There Is No Decision to Make?
Authors: Pentz Rebecca D. , Pelletier Wendy , Alderfer Melissa A. , Stegenga Kristin , Fairclough Diane L. , Hinds Pamela S.
Published: May 2012

Learning Objectives

After completing this course, the reader will be able to: When the alternative to medical treatment is likely death, ask parents and children whether they agree to the medical plan rather than suggesting they are sharing in “a decision.”Use the model of shared decision in appropriate settings, that is, those in which a bona fide choice exists.

CME This article is available for continuing medical education credit at CME.TheOncologist.com

Introduction.

Shared decision-making between health care professionals, patients, parents, and guardians is widely recommended today. However, it is unclear what happens when collaborative language is used by physicians in clinical situations for which patients and parents/guardians believe there is no decision to be made.

Methods.

We conducted a qualitative study of decision-making for pediatric allogeneic blood and marrow transplantation by interviewing patients, parents, grandparents, donor siblings, and nondonor children after the decision to proceed to transplant but before the transplantation. Each interview was audio recorded, transcribed, and coded for major themes.

Results.

In total, 107 members of 30 families at four sites were interviewed, including 15 patients, 22 mothers, 2 stepmothers, 1 grandmother, 19 fathers, 3 stepfathers, 1 grandfather, 13 sibling donors, and 31 nondonor children (siblings, half-siblings, and cousins). In all, 81% of parents/guardians, 73% of patients, 31% of donors, and 29% of other children reported there was no decision to be made. Almost all (88%) parents/guardians indicated that the physician's recommendation was a large determinant in their agreement to go forward with the transplantation. All parents/guardians reported that “agreeing to a plan” was a better description of what their consent entailed.

Conclusions.

To be respectful of patients and parents/guardians, we suggest that “agreeing to a plan” may be a better description for what parents/guardians must consider when the alternative to a transplantation is likely death. In this clinical context, the shared decision-making model with a focus on “a decision to be made” may be misleading.
Appraising infrastructure for new towns in Ireland
Authors: Hunt Dexter V. L. , Lombardi D. Rachel , Jefferson Ian , Rogers Christopher D. F. , Butler David , Memon Fayyaz A.
Published: May 2012

Over a 20 year period 1996–2016, a new 223 ha town is being developed 10 miles west of Dublin's city centre on the south side of Lucan, County Dublin, in the Republic of Ireland (ROI). This €4 billion ‘Adamstown’ development is the first of four planning schemes in ROI to be approved as a strategic development zone – an integrated planning framework deemed suitable for creating sustainable neighbourhoods in sites of strategic economic or social importance to the state. The creation of sustainable neighbourhoods in ROI is facilitated through the implementation of a checklist of 60 indicators. This paper critically examines the attempts being made to consider sustainability within the development's overall infrastructure plan, specifically: transport, energy and water services, information technology and waste. Inadequacies in the existing development are linked to shortfalls in the sustainability checklist, by way of a comparison of infrastructure-related indicators from the ROI checklist with those derived for the UK and exemplar European projects (i.e. Bedzed, UK and Freiberg, Germany). The subsequent legacy for future residents of Adamstown is then considered in the context of ‘what if’ scenarios.
Testing the importance of plant strategies on facilitation using congeners in a coastal community
Authors: He Qiang , Cui Baoshan , Bertness Mark D. , An Yuan
Published: May 2012

Much is known about how environmental stress mediates the strength of facilitation, but less is known about how different plant traits affect facilitation. We examined interactions between the shrub Tamarix chinensis and two congeneric forbs (Suaeda salsa and S. glauca) on the Chinese coast. Although S. salsa and S. glauca are both annuals, morphologically similar, and have synchronous phenologies, they have contrasting adaptive strategies. S. glauca is salt intolerant but competitively superior, and S. salsa is salt tolerant but competitively inferior. Field surveys showed that S. glauca was associated with T. chinensis canopies while S. salsa was more abundant in open areas. A T. chinensis removal experiment showed that S. glauca cover was lower and soil salinity higher after two years in removal than in control plots. Transplant experiments showed that S. salsa performance under T. chinensis canopies was reduced by competition from S. glauca and T. chinensis, while in open areas S. glauca was not affected by S. salsa competition. Thus, contrasting competitive abilities and stress tolerances of S. glauca and S. salsa underlie their facilitative and competitive interactions with T. chinensis, suggesting that plant strategies are critical to the outcome of species interactions.
Spatial fidelity of skeletal remains: elk wintering and calving grounds revealed by bones on the Yellowstone landscape
Authors: Miller Joshua H.
Published: May 2012

The spatial distributions of bones on landscape surfaces (death assemblages) may contain high‐quality data on species' landscape use. Previous investigations into the spatial fidelity of death assemblages focused on general habitat preferences of the source community. Using well‐studied elk populations of Yellowstone National Park, I test the geographic sensitivity of death assemblages by assessing the fidelity of shed elk antlers to the distribution of bull elk in late winter (documented through aerial surveys). I also test the geographic fidelity of newborn calf bones to known calving areas. The spatial distribution of antlers is highly faithful to bull elk landscape use, describing the decadally averaged distribution of wintering grounds as well or better than individual aerial surveys. Discrepancies in geographic distributions between recent wintering patterns and the multi‐decadal antler assemblage also suggests differences in winter landscape use between current and historical (wolf‐free) populations. Neonatal remains, including those partially consumed by carnivores, were always recovered in known calving areas, and all sampled calving grounds produced neonatal bones. Bone surveys are a new, minimally invasive, low‐impact tool for obtaining high‐quality historically informed data on species' geographic and habitat requirements. This tool will be particularly useful for managing sensitive species, fragile ecosystems, and poorly studied regions.
The Critical Role of Metabolic Pathways in Aging
Authors: Barzilai Nir , Huffman Derek M. , Muzumdar Radhika H. , Bartke Andrzej
Published: May 2012

Aging is characterized by a deterioration in the maintenance of homeostatic processes over time, leading to functional decline and increased risk for disease and death. The aging process is characterized metabolically by insulin resistance, changes in body composition, and physiological declines in growth hormone (GH), insulin-like growth factor-1 (IGF-1), and sex steroids. Some interventions designed to address features of aging, such as caloric restriction or visceral fat depletion, have succeeded in improving insulin action and life span in rodents. Meanwhile, pharmacologic interventions and hormonal perturbations have increased the life span of several mammalian species without necessarily addressing features of age-related metabolic decline. These interventions include inhibition of the mammalian target of rapamycin and lifetime deficiency in GH/IGF-1 signaling. However, strategies to treat aging in humans, such as hormone replacement, have mostly failed to achieve their desired response. We will briefly discuss recent advances in our understanding of the complex role of metabolic pathways in the aging process and highlight important paradoxes that have emerged from these discoveries. Although life span has been the major outcome of interest in the laboratory, a special focus is made in this study on healthspan, as improved quality of life is the goal when translated to humans.
Repair of Dimethacrylate-Based Composite Restorations by a Silorane-Based Composite: A One-Year Randomized Clinical Trial
Authors: Popoff DAV , Rosa TTA Santa , Ferreira RC , Magalhães CS , Moreira AN , Mjör IA
Published: May 2012

Purpose

To investigate clinical performance of a low-shrinkage silorane-based composite resin when used for repairing conventional dimethacrylate-based composite restorations.

Background

Despite the continued development of resin-based materials, polymerization shrinkage and shrinkage stress still require improvement. A silorane-based monomer system was recently made available for dental restorations. This report refers to the use of this material for making repairs and evaluates the clinical performance of this alternative treatment.

Materials and Methods

One operator repaired the defective dimethacrylate-based composite resin restorations that were randomly assigned to one of two treatment groups: control (n=50) repair with Adper SE Plus (3M/ESPE) and Filtek P60 Posterior Restorative (3M/ESPE), and test (n=50) repair with P90 System Adhesive Self-Etch Primer and Bond (3M/ESPE) and Filtek P90 Low Shrink Posterior Restorative (3M/ESPE). After one week, restorations were finished and polished. Two calibrated examiners (Kw≥0.78) evaluated all repaired restorations, blindly and independently, at baseline and one year. The parameters examined were marginal adaptation, anatomic form, surface roughness, marginal discoloration, postoperative sensitivity, and secondary caries. The restorations were classified as Alpha, Bravo, or Charlie, according to modified US Public Health Service criteria. Mann-Whitney and Wilcoxon tests were used to compare the groups.

Results

Of the 100 restorations repaired in this study, 93 were reexamined at baseline. Dropout from baseline to one-year recall was 11%. No statistically significant differences were found between the materials for all clinical criteria, at baseline or at one-year recall (p>0.05). No statistically significant differences were registered (p>0.05) for each material when compared for all clinical criteria at baseline and at one-year recall.

Conclusions

The hypothesis tested in this randomized controlled clinical trial was accepted. After the one-year evaluations, the silorane-based composite exhibited a similar performance compared with dimethacrylate-based composite when used to make repairs.
The 7/8 Crown: A Lost Art
Authors: McGill ST , Holmes JR
Published: May 2012

Historically, the longevity of teeth restored with gold inlays, onlays, crowns, and partial veneer restorations is excellent. However, in-office computer-aided design and computer-aided manufacturing restorations, laboratory-constructed all-ceramic bonded restorations, and conventional ceramo-metal restorations are more common. The high price of gold, the difficulty of the preparation, and the fact that most dental schools are de-emphasizing the teaching of partial veneer restorations has created a situation whereby the 7/8 crown is rarely viewed as the treatment of choice. Time and experience will determine if the new ceramic materials, along with the all-important bonding agents, can achieve the success of a well-done, all-gold restoration.
Photoelectric Properties of Screen-Printed Al-Doped ZnO Films
Authors: Ogurcovs A. , Gerbreders Vj. , Tamanis E. , Gerbreders S. , Liberts G.
Published: May 2012

Photoelectric Properties of Screen-Printed Al-Doped ZnO Films

The potential of cheap semiconductor materials in the area of solar energy use is illustrated by the example of zinc oxide (pure and Al-doped in various concentrations). Under investigation was the electric conductivity and photoelectric properties of ZnO thin films. The samples were prepared using screen-printing technique. The results of measurements point to non-linear relationships between Al concentration, photosensitivity and electrical conductivity of thin ZnO films. Optimal Al concentration for practical use of ZnO in photovoltaic devices is found to be ~ 1%. The experimental methods, technologies and results described in the paper could be used for further investigations in this area.
Antilock Brake System of Trolleybus
Authors: Safonau Andrei
Published: May 2012

Antilock Brake System of Trolleybus

The antilock brake system (ABS) was developed, which co-ordinates actions of auxiliary and working braking systems of a trolleybus. A trolleybus type 321 "Belkommunmash", equipped with the proposed ABS was tested in road conditions. The results of tests confirmed compliance of the trolleybus with requirements of the rules UN EEC No 13. Decrease in slippage of the driving wheels, improved stability, roadability and traffic safety of the trolleybus was noted.
Formation ofTransFats: During Food Preparation
Authors: Przybylski Roman , Aladedunye Felix A.
Published: May 2012

Purpose: An investigation was completed to determine how typical cooking procedures used in food preparation, such as baking and stir-frying, affect trans fats formation.

Methods: Canola oil was used as the main fat ingredient. Zucchini cake and gingersnap cookies were baked at 180° C and 200° C, while stir-fried chicken was prepared at 200° C and 275° C. The lipids from the food were extracted following the Folch procedure, and analyzed for trans fatty acids according to ISO official method 15304.

Results: Minimal changes were observed in the amount of trans fats during baking. Application of extreme temperatures during baking, which caused carbonization of the outer layer of products, yielded an insignificant increase in the amount of trans isomers. As with baking, stir-frying did not result in significant isomerization of the fatty acids, even when the oil was heated to 275° C and smoking heavily before the food was placed in it. Irrespective of the cooking procedure, linolenic acid was the most prone to isomerization with the highest amount of trans isomers formation.

Conclusions: Baking and stir-frying at normal and/or extreme temperatures do not significantly affect the amounts of trans fats. Likewise, heating oil to the smoking point during stirfrying may decrease the amount of polyunsaturated fatty acids because of oxidative degradation.
Time-Dependent Effects of Pre-Aging 3D Polymer Scaffolds in Cell Culture Medium on Cell Proliferation
Authors: Chatterjee Kaushik , Hung Stevephen , Kumar Girish , Simon Carl G.
Published: May 2012

Protein adsorption is known to direct biological response to biomaterials and is important in determining cellular response in tissue scaffolds. In this study we investigated the effect of the duration of protein adsorption to 3D polymer scaffolds on cell attachment and proliferation. 3D macro-porous polymer scaffolds were pre-aged in serum-containing culture medium for 5 min, 1 d or 7 d prior to seeding osteoblasts. The total amount of protein adsorbed was found to increase with pre-ageing time. Cell attachment and proliferation were measured 1 d and 14 d, respectively, after cell seeding. Osteoblast proliferation, but not attachment, increased with scaffold pre-ageing time and amount of adsorbed serum protein. These results demonstrate that the amount of time that scaffolds are exposed to serum-containing medium can affect cell proliferation and suggest that these effects are mediated by differences in the amount of protein adsorption.
Categorization of Indoor Places Using the Kinect Sensor
Authors: Mozos Oscar Martinez , Mizutani Hitoshi , Kurazume Ryo , Hasegawa Tsutomu
Published: May 2012

The categorization of places in indoor environments is an important capability for service robots working and interacting with humans. In this paper we present a method to categorize different areas in indoor environments using a mobile robot equipped with a Kinect camera. Our approach transforms depth and grey scale images taken at each place into histograms of local binary patterns (LBPs) whose dimensionality is further reduced following a uniform criterion. The histograms are then combined into a single feature vector which is categorized using a supervised method. In this work we compare the performance of support vector machines and random forests as supervised classifiers. Finally, we apply our technique to distinguish five different place categories: corridors, laboratories, offices, kitchens, and study rooms. Experimental results show that we can categorize these places with high accuracy using our approach.
Limited Sampling Strategies to Estimate the Area under the Concentration-time Curve
Authors: Fukumoto M. , Bax L. , Kohno A. , Morishita Y. , Tsuruta H.
Published: May 2012

Background: Over 100 limited sampling strategies (LSSs) have been proposed to reduce the number of blood samples necessary to estimate the area under the concentration-time curve (AUC). The conditions under which these strategies succeed or fail remain to be clarified.

Objectives: We investigated the accuracy of existing LSSs both theoretically and numerically by Monte Carlo simulation. We also proposed two new methods for more accurate AUC estimations.

Methods: We evaluated the following existing methods theoretically: i) nonlinear curve fitting algorithm (NLF), ii) the trapezium rule with exponential curve approximation (TZE), and iii) multiple linear regression (MLR). Taking busulfan (BU) as a test drug, we generated a set of theoretical concentration-time curves based on the identified distribution of pharmacokinetic parameters of BU and re-evaluated the existing LSSs using these virtual validation profiles. Based on the evaluation results, we improved the TZE so that unrealistic parameter values were not used. We also proposed a new estimation method in which the most likely curve was selected from a set of pre-generated theoretical concentration-time curves.

Results: Our evaluation, based on clinical profiles and a virtual validation set, revealed: i) NLF sometimes overestimated the absorption rate constant Ka, ii) TZE overestimated AUC over 280% when Ka is small, and iii) MLR underestimated AUC over 30% when the elimination rate constant Ke is small. These results were consistent with our mathematical evaluations for these methods. In contrast, our two new methods had little bias and good precision.

Conclusions: Our investigation revealed that existing LSSs induce different but specific biases in the estimation of AUC. Our two new LSSs, a modified TZE and one using model concentration-time curves, provided accurate and precise estimations of AUC.
Microsatellite markers for Bistorta vivipara (Polygonaceae)
Authors: Vik Unni , Carlsen Tor , Eidesen Pernille Bronken , Brysting Anne Krag , Kauserud Håvard
Published: May 2012

• Premise of the study: Using genomic shotgun 454 sequencing, 50 candidate microsatellite markers were targeted for the arctic–alpine polyploid perennial herb Bistorta vivipara to distinguish between individual genets and ramets within a population.

• Methods and Results: Out of the 50 markers, 31 were polymorphic for seven test samples. We have developed a multiplex protocol for 16 of these microsatellite markers.

• Conclusions: Our results show that the microsatellite markers provide a powerful tool for the research on genetic variation of B. vivipara.
Isolation and characterization of microsatellite markers from Clematoclethra scandens (Actinidiaceae)
Authors: Li Lu , Chen Li , Zhang Zhi‐Rong , Xiao Long‐Qian
Published: May 2012

• Premise of the study: Microsatellite makers were developed for Clematoclethra scandens to investigate its population genetics and speciation.

• Methods and Results: A total of 36 microsatellite markers were isolated using the Fast Isolation by AFLP of Sequences COntaining repeats (FIASCO) method. Their polymorphisms were assessed in two natural populations. The results showed that 30 markers displayed prominent polymorphisms and six markers were monomorphic.

• Conclusions: These microsatellite loci will facilitate further studies on population genetics and speciation of C. scandens.
Investigaciones sobre el aseguramiento de la calidad de los cilindros de laminación indefinida mediante análisis de regresión múltiple
Authors: Kiss I.
Published: May 2012

Con este trabajo se ha logrado asegurar la calidad de los cilindros de laminación, debido fundamentalmente a la aportación de una determinada composición química a los materiales cilíndricos. Esta composición química mejorada, puede desarrollar de una forma efiicaz las propiedades de explotación, donde estos cilindros de laminación podrán ser fabricados, ofreciendo mejores resultados. El trabajo se presenta de una forma científica, aportando los resultados de una investigación experimental en el área de los cilindros de laminación. Dicha investigación contiene elementos suficientes y de inmediata utilidad práctica para las empresas metalúrgicas, y así de esta forma, mejorar la calidad de los cilindros de laminación. El objetivo principal es el aumento de la durabilidad y la seguridad en la explotación. En este proceso se presenta un análisis de la composición química y de la influencia sobre las propiedades mecánicas de los cilindros de laminación indefinida. Presentamos algunas correlaciones matemáticas añadiendo una interpretación gráfica entre la dureza (en la superficie de trabajo y el cuello) y la composición química. La determinación de las correlaciones dobles y triples, que son realmente útiles en la práctica de la fundición, nos permite determinar los límites de variación de la composición química, con vistas a obtener los valores óptimos de la dureza.Se podrá observar una interpretación matemática de la influencia de la composición química, sobre la dureza de estos cilindros de laminación. En este sentido, realizamos el análisis de regresión múltiple el cual puede aportar un importante instrumento estadístico para la investigación de las relaciones entre las variables. Los resultados matemáticamente modelados, pueden ser descritos mediante una serie de ecuaciones multicomponentes determinados por los espacios con dimensiones 3 y 4. Las superficies de regresión, curvas de niveles y volúmenes de variaciones, pueden ser representados e interpretados por técnicos , considerando estos como diagramas de correlación entre las variables analizadas. En este sentido, los resultados de estas investigaciones pueden ser utilizados por ingenieros de las fundiciones y sectores laminadores, ofreciendo garantías de calidad de los cilindros de laminación. en fase de producción, así como la explotación de estos, qué llevará, inevitablemente, el aseguramiento de una calidad de los laminados producidos.
Estudio de los mecanismos de descomposición isotérmica de austenita en perlita en un acero 0,44C-0,73Mn
Authors: Aranda M. M. , Pimentel G. , Cornide J. , Capdevila C.
Published: May 2012

El objetivo de este trabajo se centra en el estudio de los mecanismos de descomposición isotérmica de la austenita en perlita en un acero de composición 0,44C-0,73 Mn. En particular, se estudia cómo afecta la temperatura de austenización (Tγ), y por tanto, el tamaño de grano austenítico de partida (TGA), en la cinética de formación de la perlita. Se ha comprobado que existe una relación directa entre Tγ y el tamaño medio de las colonias perlíticas. Por el contario, el espaciado interlaminar perlítico no depende de Tγ, sino que está controlado por la temperatura de descomposición isotérmica (T), de la austenita en perlita. Finalmente se ha observado que la cinética de formación de perlita se ve acelerada para el caso de TGA pequeños y cuando el mecanismo predominante en el rango de temperaturas de trabajo es la difusión en volumen del carbono.
A Numerical Study of Quantum Decoherence
Authors: Adami Riccardo , Negulescu Claudia
Published: May 2012

The present paper provides a numerical investigation of the decoherence effect induced on a quantum heavy particle by the scattering with a light one. The time dependent two-particle Schrödinger equation is solved by means of a time-splitting method. The damping undergone by the non-diagonal terms of the heavy particle density matrix is estimated numerically as well as the error in the Joos-Zeh approximation formula.
Numerical Simulation of Glottal Flow in Interaction with Self Oscillating Vocal Folds: Comparison of Finite Element Approximation with a Simplified Model
Authors: Sváček P. , Horáček J.
Published: May 2012

In this paper the numerical method for solution of an aeroelastic model describing the interactions of air flow with vocal folds is described. The flow is modelled by the incompressible Navier-Stokes equations spatially discretized with the aid of the stabilized finite element method. The motion of the computational domain is treated with the aid of the Arbitrary Lagrangian Eulerian method. The structure dynamics is replaced by a mechanically equivalent system with the two degrees of freedom governed by a system of ordinary differential equations and discretized in time with the aid of an implicit multistep method and strongly coupled with the flow model. The influence of inlet/outlet boundary conditions is studied and the numerical analysis is performed and compared to the related results from literature.
Viscoelastic Immersed Boundary Methods for Zero Reynolds Number Flow
Authors: Strychalski Wanda , Guy Robert D.
Published: May 2012

The immersed boundary method has been extensively used to simulate the motion of elastic structures immersed in a viscous fluid. For some applications, such as modeling biological materials, capturing internal boundary viscosity is important. We present numerical methods for simulating Kelvin-Voigt and standard linear viscoelastic structures immersed in zero Reynolds number flow. We find that the explicit time immersed boundary update is unconditionally unstable above a critical boundary to fluid viscosity ratio for a Kelvin-Voigt material. We also show there is a severe time step restriction when simulating a standard linear boundary with a small relaxation time scale using the same explicit update. A stable implicit method is presented to overcome these computation challenges.
A Variational Model for Two-Phase Immiscible Electroosmotic Flow at Solid Surfaces
Authors: Shao Sihong , Qian Tiezheng
Published: May 2012

We develop a continuum hydrodynamic model for two-phase immiscible flows that involve electroosmotic effect in an electrolyte and moving contact line at solid surfaces. The model is derived through a variational approach based on the On-sager principle of minimum energy dissipation. This approach was first presented in the derivation of a continuum hydrodynamic model for moving contact line in neutral two-phase immiscible flows (Qian, Wang, and Sheng, J. Fluid Mech. 564, 333-360 (2006)). Physically, the electroosmotic effect can be formulated by the Onsager principle as well in the linear response regime. Therefore, the same variational approach is applied here to the derivation of the continuum hydrodynamic model for charged two-phase immiscible flows where one fluid component is an electrolyte exhibiting electroosmotic effect on a charged surface. A phase field is employed to model the diffuse interface between two immiscible fluid components, one being the electrolyte and the other a nonconductive fluid, both allowed to slip at solid surfaces. Our model consists of the incompressible Navier-Stokes equation for momentum transport, the Nernst-Planck equation for ion transport, the Cahn-Hilliard phase-field equation for interface motion, and the Poisson equation for electric potential, along with all the necessary boundary conditions. In particular, all the dynamic boundary conditions at solid surfaces, including the generalized Navier boundary condition for slip, are derived together with the equations of motion in the bulk region. Numerical examples in two-dimensional space, which involve overlapped electric double layer fields, have been presented to demonstrate the validity and applicability of the model, and a few salient features of the two-phase immiscible electroosmotic flows at solid surface. The wall slip in the vicinity ofmoving contact line and the Smoluchowski slip in the electric double layer are both investigated.
Statistics of Particle Suspensions in Turbulent Channel Flow
Authors: Zhao Lihao , Andersson Helge I.
Published: May 2012

Particle dynamics in a turbulent channel flow is considered. The effects of particle concentration and Reynolds number on the particle velocity statistics are investigated. Four different particle response times, τ+=1, 5, 30 and 100, are examined for three different Reynolds numbers, Re*=200, 360 and 790 (based on channel height and friction velocity). The particle concentration evolves with time and statistics obtained during three different sampling periods might be distinctly different. The mean and fluctuating particle velocities are substantially affected both by the particle response time and by the Reynolds number of the flow.
An Iterative Two-Fluid Pressure Solver Based on the Immersed Interface Method
Authors: Xu Sheng
Published: May 2012

An iterative solver based on the immersed interface method is proposed to solve the pressure in a two-fluid flow on a Cartesian grid with second-order accuracy in the infinity norm. The iteration is constructed by introducing an unsteady term in the pressure Poisson equation. In each iteration step, a Helmholtz equation is solved on the Cartesian grid using FFT. The combination of the iteration and the immersed interface method enables the solver to handle various jump conditions across two-fluid interfaces. This solver can also be used to solve Poisson equations on irregular domains.
High-Order Low Dissipation Conforming Finite-Element Discretization of the Maxwell Equations
Authors: Jund Sébastien , Salmon Stéphanie , Sonnendrücker Eric
Published: May 2012

In this paper, we study high order discretization methods for solving the Maxwell equations on hybrid triangle-quad meshes. We have developed high order finite edge element methods coupled with different high order time schemes and we compare results and efficiency for several schemes. We introduce in particular a class of simple high order low dissipation time schemes based on a modified Taylor expansion.
Composite Coherent States Approximation for One-Dimensional Multi-Phased Wave Functions
Authors: Yin Dongsheng , Zheng Chunxiong
Published: May 2012

The coherent states approximation for one-dimensional multi-phased wave functions is considered in this paper. The wave functions are assumed to oscillate on a characteristic wave length 0(ε) with ε ≪ 1. A parameter recovery algorithm is first developed for single-phased wave function based on a moment asymptotic analysis. This algorithm is then extended to multi-phased wave functions. If cross points or caustics exist, the coherent states approximation algorithm based on the parameter recovery will fail in some local regions. In this case, we resort to the windowed Fourier transform technique, and propose a composite coherent states approximation method. Numerical experiments show that the number of coherent states derived by the proposed method is much less than that by the direct windowed Fourier transform technique.
Computational Methods for Electromechanical Fields in Self-Assembled Quantum Dots
Authors: Barettin D. , Madsen S. , Lassen B. , Willatzen M.
Published: May 2012

A detailed comparison of continuum and valence force field strain calculations in quantum-dot structures is presented with particular emphasis to boundary conditions, their implementation in the finite-element method, and associated implications for electronic states. The first part of this work provides the equation framework for the elastic continuum model including piezoelectric effects in crystal structures as well as detailing the Keating model equations used in the atomistic valence force field calculations. Given the variety of possible structure shapes, a choice of pyramidal, spherical and cubic-dot shapes is made having in mind their pronounced shape differences and practical relevance. In this part boundary conditions are also considered; in particular the relevance of imposing different types of boundary conditions is highlighted and discussed.
Computational Investigation of the Interaction Between Hydrogen Atoms and an Intense Circularly Polarized Laser Field
Authors: Yang Lifeng , Xu Wang , Zhang Qiren , Luo Wen , Pan Qiangyan , Cai Xiaolu , Fan Gongtao , Li Yongjiang , Xu Benji , Yan Zhe , Fan Guangwei , An Zhendong
Published: May 2012

The study of interactions between a high-power laser and atoms has been one of the fundamental and interesting topics in strong field physics for decades. Based on a nonperturbative model, ten years ago, we developed a set of programs to facilitate the study of interactions between a circularly polarized laser and atomic hydrogen. These programs included only contribution from the bound states of the hydrogen atom. However, as the laser intensity increases, contribution from continuum states to the excitation and ionization processes becomes larger and can no longer be neglected. Furthermore, because the original code is not able to add this contribution directly due to its many disadvantages, a major upgrade of the code is required before including the contribution from continuum states in future. In this paper, first we deduce some important formulas for contribution of continuum states and present modifications and tests for the upgraded code in detail. Second we show some comparisons among new results, old results from the original codes and the available experimental data. Overall the new result agrees with experimental data well. Last we present our calculation of above-threshold ionization (ATI) rate and compare it with a pertuba-tive calculation. The comparison shows that our nonperturbative calculation can also produce ATI peak suppression.
Oblique Drop Impact on Deep and Shallow Liquid
Authors: Ray B. , Biswas G. , Sharma A.
Published: May 2012

Numerical simulations using CLSVOF (coupled level set and volume of fluid) method are performed to investigate the coalescence and splashing regimes when a spherical water drop hits on the water surface with an impingement angle. Impingement angle is the angle between the velocity vector of primary drop and the normal vector to water surface. The effect of impingement angle, impact velocity and the height of target liquid are carried out. The impingement angle is varied from 0° to 90° showing the gradual change in phenomena. The formation of ship pro like shape, liquid sheet, secondary drops and crater are seen. Crater height, crater displacement, crown height and crown angle are calculated and the change in the parameters with change in impingement angle is noted.
Simulation of Plasma Flow Injection with Multi-Hierarchy Model Aiming Magnetic Reconnection Studies
Authors: Usami S. , Ohtani H. , Horiuchi R. , Den M.
Published: May 2012

A multi-hierarchy simulation model aiming magnetic reconnection studies is developed and improved in which macroscopic and microscopic physics are computed consistently and simultaneously. Macroscopic physics is solved by mag-netohydrodynamics (MHD) algorithm, while microscopic dynamics is expressed by particle-in-cell (PIC) algorithm. The multi-hierarchy model relies on the domain decomposition method, and macro- and micro-hierarchies are interlocked smoothly by hand-shake scheme. As examination, plasma flow injection is simulated in the multi-hierarchy model. It is observed that plasmas flow from a macro-hierarchy to a micro-hierarchy across the magnetic field smoothly and continuously.
A New Variational Model with Dual Level Set Functions for Selective Segmentation
Authors: Rada Lavdie , Chen Ke
Published: May 2012

In this paper we present a selective segmentation model using a dual level set variational formulation. Our variational model aims to segment all objects with one level set function (global) and the selected object, which is the closest to the geometric constraints (markers), with another level set (local). It is a combination of edge detection, markers distance function and active contour without edges. Experimental results show that our model is more robust than previous work.
An Immersed Interface Method for the Simulation of Inextensible Interfaces in Viscous Fluids
Authors: Tan Zhijun , Le D. V. , Lim K. M. , Khoo B. C.
Published: May 2012

In this paper, an immersed interface method is presented to simulate the dynamics of inextensible interfaces in an incompressible flow. The tension is introduced as an augmented variable to satisfy the constraint of interface inextensibility and the resulting augmented system is solved by the GMRES method. In this work, the arclength of the interface is locally and globally conserved as the enclosed region undergoes deformation. The forces at the interface are calculated from the configuration of the interface and the computed augmented variable, and then applied to the fluid through the related jump conditions. The governing equations are discretized on a MAC grid via a second-order finite difference scheme which incorporates jump contributions and solved by the conjugate gradient Uzawa-type method. The proposed method is applied to several examples including the deformation of a liquid capsule with inextensible interfaces in a shear flow. Numerical results reveal that both the area enclosed by interface and arclength of interface are conserved well simultaneously. These provide further evidence on the capability of the present method to simulate incompressible flows involving inextensible interfaces.
Improving the High Order Spectral Volume Formulation Using a Diffusion Regulator
Authors: Kannan Ravi , Wang Zhijian
Published: May 2012

The concept of diffusion regulation (DR) was originally proposed by Jaisankar for traditional second order finite volume Euler solvers. This was used to decrease the inherent dissipation associated with using approximate Riemann solvers. In this paper, the above concept is extended to the high order spectral volume (SV) method. The DR formulation was used in conjunction with the Rusanov flux to handle the inviscid flux terms. Numerical experiments were conducted to compare and contrast the original and the DR formulations. These experiments demonstrated (i) retention of high order accuracy for the new formulation, (ii) higher fidelity of the DR formulation, when compared to the original scheme for all orders and (iii) straightforward extension to Navier Stokes equations, since the DR does not interfere with the discretization of the viscous fluxes. In general, the 2D numerical results are very promising and indicate that the approach has a great potential for 3D flow problems.
Numerical Methods for Fluid-Structure Interaction — A Review
Authors: Hou Gene , Wang Jin , Layton Anita
Published: May 2012

The interactions between incompressible fluid flows and immersed structures are nonlinear multi-physics phenomena that have applications to a wide range of scientific and engineering disciplines. In this article, we review representative numerical methods based on conforming and non-conforming meshes that are currently available for computing fluid-structure interaction problems, with an emphasis on some of the recent developments in the field. A goal is to categorize the selected methods and assess their accuracy and efficiency. We discuss challenges faced by researchers in this field, and we emphasize the importance of interdisciplinary effort for advancing the study in fluid-structure interactions.
Phase-Field Models for Multi-Component Fluid Flows
Authors: Kim Junseok
Published: May 2012

In this paper, we review the recent development of phase-field models and their numerical methods for multi-component fluid flows with interfacial phenomena. The models consist of a Navier-Stokes system coupled with a multi-component Cahn-Hilliard system through a phase-field dependent surface tension force, variable density and viscosity, and the advection term. The classical infinitely thin boundary of separation between two immiscible fluids is replaced by a transition region of a small but finite width, across which the composition of the mixture changes continuously. A constant level set of the phase-field is used to capture the interface between two immiscible fluids. Phase-field methods are capable of computing topological changes such as splitting and merging, and thus have been applied successfully to multi-component fluid flows involving large interface deformations. Practical applications are provided to illustrate the usefulness of using a phase-field method. Computational results of various experiments show the accuracy and effectiveness of phase-field models.