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Crescimento e caracterização de soluções sólidas óxidas.; Growth and caracterization of the oxides solid solutions.

Andreeta, Jose Pedro
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 26/09/1984 Português
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Experimentos sistemáticos de crescimento de cristais pelo método de soluções sólidas óxidas de GdAlO3:Cr3+ (estrutura pseudo perovskita), foram efetuados em diversas composições de solventes. Os perfis de concentrações dopante (Cr3+) e do solvente (Pb),em amostras previamente selecionadas e os coeficientes de segregação efetivos foram determinados e comparados com os dos cristais crescidos pelo método Czochralski. Modelos teóricos foram desenvolvidos para o entendimento dos resultados experimentais e outros são propostos com o objetivo de fornecer tratamentos alternativos para os efeitos dos parâmetros de crescimento tais como: flutuações térmicas, forma geométrica nucleações secundárias, evaporação do dopante, reações químicas e estabilidade de crescimento na homogeneidade das soluções sólidas. Devido ao interesse científico-tecnológico também foram crescidos outros cristais de estrutura perovskita como GdAlO3:La3+, LaAlO3:Cr3+ e NdAlO3:La3+ pelo método de fluxo e GdAlO3:Cr3+:La3+, pelo método Czocharalski e os resultados das experiências de crescimento estão descritas neste trabalho.; Systematic growth experiments by flux method of the oxides solid solutions of GdAlO3:Cr3+ (perovskite type) were done with several solvents compositions. The doping (Cr3+) and solvent (Pb) concentrations profiles in selected samples...

Contribuições ao estudo da não-idealidade de soluções proteicas.; Contributions to the study of non-ideality of protein solutions.

Alves, Kelly Cristina Nascimento
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 26/03/2013 Português
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O estudo de soluções proteicas visando à modelagem e à simulação de processos de recuperação e purificação de bioprodutos passa necessariamente pelo estudo da não idealidade, em sentido termodinâmico, destas soluções. Para sistemas em que a concentração de proteína seja baixa, situação comumente presente nestes processos, a principal maneira de avaliar experimentalmente a não idealidade é por meio da determinação da pressão osmótica gerada pela proteína. Deste modo, os objetivos deste trabalho foram: estudar a influência de co-solventes na pressão osmótica de soluções proteicas, verificar a integridade das estruturas secundária e terciária das proteínas nessas soluções, e modelar termodinamicamente os dados de pressão osmótica obtidos. A pressão osmótica foi determinada diretamente por osmometria de membrana, usando soluções de referência com mesma concentração de co-solvente e pH, mas isentas de proteínas. Obtiveram-se dados de pressão osmótica, em função da concentração proteica, de cinco diferentes proteínas (albumina de soro bovino, imunoglobulina G humana, ovalbumina, -lactoglobulina e lisozima) em soluções contendo co-solventes como o polietileno glicol (de diversos tamanhos de cadeia) e sais (sulfato de amônio...

Temperature and concentration dependence of heat capacity of model aqueous solutions

Darros-Barbosa, R.; Balaban, M. O.; Teixeira, A. A.
Fonte: Marcel Dekker Inc Publicador: Marcel Dekker Inc
Tipo: Artigo de Revista Científica Formato: 239-258
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Heat capacities of binary aqueous solutions of different concentrations of sucrose, glucose, fructose, citric acid, malic acid, and inorganic salts were measured with a differential scanning calorimeter in the temperature range from 5degreesC to 65degreesC. Heat capacity increased with increasing water content and increasing temperature. At low concentrations, heat capacity approached that of pure water, with a less pronounced effect of temperature, and similar abnormal behavior of pure water with a minimum around 30degreesC-40degreesC. Literature data, when available agreed relatively well with experimental values. A correction factor, based on the assumption of chemical equilibrium between liquid and gas phase in the Differential Scanning Calorimeter, was proposed to correct for the water evaporation due to temperature rise. Experimental data were fitted to predictive models. Excess molar heat capacity was calculated using the Redlich-Kister equation to represent the deviation from the additive ideal model.

Rheology of supersaturated sucrose solutions

Quintas, M.; Brandão, T.R.S.; Silva, C.L.M.; Cunha, R.L.
Fonte: Elsevier Publicador: Elsevier
Tipo: Artigo de Revista Científica
Publicado em //2006 Português
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Sucrose solutions, with concentrations near or superior to saturation, present high potentialities for the candy and pastry industries. Creep measurements under small stresses were done to obtain the rheological properties of highly concentrated sucrose solutions, since such solutions could be in a metastable state and tend to crystallise. The viscosities of these solutions, from 70.0% to 85.2% (w/w), were determined experimentally at different temperatures, from 0 to 90 C. The temperature dependence of viscosity was studied using experimental and published data for, respectively, high and low concentrations (<70% (w/w)). Results showed that the Arrhenius model describes better the temperature dependence of viscosity for concentrations under saturation and in the high concentration regime the WLF model had a better predicting ability. The effect of concentration on viscosity was observed and included in the Arrhenius and WLF models parameters. The proposed models were able to successfully describe the data in the corresponding concentration range. These results can be used in predicting the viscosities of syrups for either process design or new products formulation.

Improving contact center cost efficiency and customer experience in a retail company

Oliveira, Guilherme da Silva Correia de
Fonte: NSBE - UNL Publicador: NSBE - UNL
Tipo: Dissertação de Mestrado
Publicado em /01/2014 Português
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A Work Project, presented as part of the requirements for the Award of a Masters Degree in Management from the NOVA – School of Business and Economics; The purpose of this Work Project is to recommend feasible solutions aimed to decrease the costs of a Retail Company Contact Center associated to the high volume of inbound calls. In order to promote a higher impact on the volume of calls reduction, the Work Project focuses on the Portuguese Customers contacts regarding repair processes within the defined period for the Company to proceed with the repair and centers the research on a profound understanding of the main motivations for the Customers to call. The proposed solutions diverse from Stores and Contact Center new specific training modules to specific actions as a follow up SMS adapted to the different types of processes, a new IVR, among others. For the solutions which are possible to compute a cost-benefit analysis, the annual savings may reach values between 41.500€ and 47.100€ for the Company.

Keeping family physicians in rural practice. Solutions favoured by rural physicians and family medicine residents.

Rourke, James T. B.; Incitti, Filomena; Rourke, Leslie L.; Kennard, MaryAnn
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /09/2003 Português
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OBJECTIVE: To determine how family medicine residents and practising rural physicians rate possible solutions for recruiting and sustaining physicians in rural practice. DESIGN: Cross-sectional mailed survey. SETTING: Rural family practices and family medicine residency programs in Ontario. PARTICIPANTS: Two hundred seventy-six physicians and 210 residents. MAIN OUTCOME MEASURES Ratings of proposed solutions on a 4-point scale from "very unimportant" to "very important". RESULTS: Rural family physicians rated funding for learner-driven continuing medical education (CME) and limiting on-call duty to 1 night in 5 as the most important education and practice solutions, respectively. Residents rated an alternate payment plan to include time off for attending and teaching CME and comprehensive payment plans with a guaranteed income for locums as the most important education and practice solutions, respectively. CONCLUSION: Residents and physicians rated solutions very similarly. A comprehensive package of the highest-rated solutions could help recruit and sustain physicians in rural practice because the solutions were developed by experts on rural practice and rated by family medicine residents and practising rural physicians.

Solutions for Determining the Significance Region Using the Johnson-Neyman Type Procedure in Generalized Linear (Mixed) Models

Lazar, Ann A.; Zerbe, Gary O.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /12/2011 Português
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Researchers often compare the relationship between an outcome and covariate for two or more groups by evaluating whether the fitted regression curves differ significantly. When they do, researchers need to determine the “significance region,” or the values of the covariate where the curves significantly differ. In analysis of covariance (ANCOVA), the Johnson-Neyman procedure can be used to determine the significance region; for the hierarchical linear model (HLM), the Miyazaki and Maier (M-M) procedure has been suggested. However, neither procedure can assume nonnormally distributed data. Furthermore, the M-M procedure produces biased (downward) results because it uses the Wald test, does not control the inflated Type I error rate due to multiple testing, and requires implementing multiple software packages to determine the significance region. In this article, we address these limitations by proposing solutions for determining the significance region suitable for generalized linear (mixed) model (GLM or GLMM). These proposed solutions incorporate test statistics that resolve the biased results, control the Type I error rate using Scheffé’s method, and uses a single statistical software package to determine the significance region.

Local Barriers and Solutions to Improve Care-Seeking for Childhood Pneumonia, Diarrhoea and Malaria in Kenya, Nigeria and Niger: A Qualitative Study

Bedford, K. Juliet A.; Sharkey, Alyssa B.
Fonte: Public Library of Science Publicador: Public Library of Science
Tipo: Artigo de Revista Científica
Publicado em 27/06/2014 Português
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We present qualitative research findings on care-seeking and treatment uptake for pneumonia, diarrhoea and malaria among children under 5 in Kenya, Nigeria and Niger. The study aimed to determine the barriers caregivers face in accessing treatment for these conditions; to identify local solutions that facilitate more timely access to treatment; and to present these findings as a platform from which to develop context-specific strategies to improve care-seeking for childhood illness. Kenya, Nigeria and Niger are three high burden countries with low rates of related treatment coverage, particularly in underserved areas. Data were collected in Homa Bay County in Nyanza Province, Kenya; in Kebbi and Cross River States, Nigeria; and in the Maradi and Tillabéri regions of Niger. Primary caregivers of children under 5 who did not regularly engage with health services or present their child at a health facility during illness episodes were purposively selected for interview. Data underwent rigorous thematic analysis. We organise the identified barriers and related solutions by theme: financial barriers; distance/location of health facilities; socio-cultural barriers and gender dynamics; knowledge and information barriers; and health facility deterrents. The relative importance of each differed by locality. Participant suggested solutions ranged from community-level actions to facility-level and more policy-oriented actions...

Oral Health Disparities and Unmet Dental Needs among Preschool Children in Chelsea, MA: Exploring Mechanisms, Defining Solutions

Isong, Inyang; Dantas, Laila; Gerard, Macda; Kuhlthau, Karen
Fonte: Harvard University Publicador: Harvard University
Tipo: Artigo de Revista Científica
Português
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Background: Significant disparities exist in children’s receipt of preventive dental care (PDC) in the United States. Many of the children at greatest risk of dental disease do not receive timely PDC; when they do receive dental care, it is often more for relief of dental pain. Chelsea is a low-income, diverse Massachusetts community with high rates of untreated childhood caries. There are various dental resources available in Chelsea, yet many children do not access dental care at levels equivalent to their needs. Objective: Using Chelsea as a case-study, to explore factors contributing to forgone PDC (including the age 1 dental visit) in an in-depth way. Methods: We used a qualitative study design that included semi-structured interviews with parents of preschool children residing in Chelsea, and Chelsea-based providers including pediatricians, dentists, a dental hygienist and early childhood care providers. We examined: a) parents’ dental attitudes and oral health cultural beliefs; b) parents’ and providers’ perspectives on facilitators and barriers to PDC, reasons for unmet needs, and proposed solutions to address the problem. We recorded, transcribed and independently coded all interviews. Using rigorous, iterative qualitative data analyses procedures...

The Efficient Computation of Bounds for Functionals of Finite Element Solutions in Large Strain Elasticity

Bonet, J.; Huerta, A.; Peraire, Jaime
Fonte: MIT - Massachusetts Institute of Technology Publicador: MIT - Massachusetts Institute of Technology
Tipo: Artigo de Revista Científica Formato: 562584 bytes; application/pdf
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We present an implicit a-posteriori finite element procedure to compute bounds for functional outputs of finite element solutions in large strain elasticity. The method proposed relies on the existence of a potential energy functional whose local minima, over a space of suitably chosen continuous functions, corresponds to the problem solution. The output of interest is cast as a constrained minimization problem over an enlarged discontinuous finite element space. A Lagrangian is formed were the multipliers are an adjoint solution, which enforces equilibrium, and hybrid fluxes, which constrain the solution to be continuous. By computing approximate values for the multipliers on a coarse mesh, strict upper and lower bounds for the output of interest on a suitably refined mesh, are obtained. This requires a minimization over a discontinuous space, which can be carried out locally at low cost. The computed bounds are uniformly valid regardless of the size of the underlying coarse discretization. The method is demonstrated with two applications involving large strain plane stress incompressible neo-hookean hyperelasticity.; Singapore-MIT Alliance (SMA)

Federal information systems management : problems, solutions, and more problems

Boger, Dan C.; Jones, Carl R.; Lyons, Norman R.
Fonte: Monterey, California. Naval Postgraduate School Publicador: Monterey, California. Naval Postgraduate School
Tipo: Relatório
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Although there are numerous problems associated with the management of Federal information systems, the usual solutions proposed for these problems have had and will have little, if any, effects. This paper examines the characteristics of Federal information systems and shows that most proposed solutions are directed at symptoms of the problems and not at their underlying causes. These solutions do not reflect the public sector nature of Federal information systems and hence, are either unrealistic or ineffectual. The authors do not propose another panacea

End-to-end security solutions for Internet-integrated Wireless Sensor Networks

Granjal, António Jorge da Costa
Fonte: Universidade de Coimbra Publicador: Universidade de Coimbra
Tipo: Tese de Doutorado
Português
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A investigação em soluções tecnológicas para as Redes de Sensores Sem Fios (RSSF) despertou grande interesse e inúmeros esforços ao nível da investigação em anos recentes. O objetivo inicial de tais redes foi o de providenciar uma base tecnológica que permitisse dispor de aplicações sensoriais distribuídas, desenhadas com propósitos bem específicos nas mais diversas áreas de investigação e aplicação. Uma característica distintiva das RSSF é a utilização de dispositivos com capacidade para comunicar por radiofrequência e de “sentir” e “atuar” no meio físico que os rodeia. Tal capacidade permite, na prática, o desenvolvimento e a utilização de soluções verdadeiramente inovadoras implementadas com recurso a aplicações distribuídas capazes de interagir com o mundo físico. As aplicações originais das RSSF visavam essencialmente a construção de soluções eficientes para problemas bem delimitados e, como consequência, tais redes não eram projetadas com o objetivo de suportar diferentes tipos de aplicações ou mecanismos de comunicação adaptáveis a diferentes propósitos de utilização. Podemos igualmente verificar que os mecanismos de comunicação e segurança utilizados em tais aplicações eram desenhados de acordo com o seu propósito específico de utilização. Por conseguinte...

'Missing Women' in the South Caucasus; Local Perceptions and Proposed Solutions

Dudwick, Nora
Fonte: World Bank, Washington, DC Publicador: World Bank, Washington, DC
Tipo: Report; Publications & Research; Publications & Research :: Working Paper
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This report, Europe and Central Asia - Missing Women in the South Caucasus : Local perceptions and proposed solutions, discusses research conducted on skewed sex ratios in the South Caucasus. It discusses (i) the factors that encourage sex selection in Armenia, Azerbaijan and Georgia, (ii) whether and how these might be changing; (iii) public awareness of and attitudes regarding skewed sex rations; and to propose potential policy responses. The report examines the following: factors contributing to smaller families and unbalanced sex rations in the South Caucasus, the reasons for underlying son preference, attitudes toward daughters, factors that make women vulnerable to pressures to produce sons. It also describes how intergenerational and gender relationships are starting to change and proposes some recommendations for addressing the factors that underlie unbalanced sex rations.

Additional scaled solutions to Richards' equation for infiltration and drainage

Sadeghi, M.; Ghahraman, B.; Ziaei, A. N.; Davary, K.; Reichardt, K.
Fonte: ELSEVIER SCIENCE BV; AMSTERDAM Publicador: ELSEVIER SCIENCE BV; AMSTERDAM
Tipo: Artigo de Revista Científica
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Warrick and Hussen developed in the nineties of the last century a method to scale Richards' equation (RE) for similar soils. In this paper, new scaled solutions are added to the method of Warrick and Hussen considering a wider range of soils regardless of their dissimilarity. Gardner-Kozeny hydraulic functions are adopted instead of Brooks-Corey functions used originally by Warrick and Hussen. These functions allow to reduce the dependence of the scaled RE on the soil properties. To evaluate the proposed method (PM), the scaled RE was solved numerically using a finite difference method with a fully implicit scheme. Three cases were considered: constant-head infiltration, constant-flux infiltration, and drainage of an initially uniform wet soil. The results for five texturally different soils ranging from sand to clay (adopted from the literature) showed that the scaled solutions were invariant to a satisfactory degree. However, slight deviations were observed mainly for the sandy soil. Moreover, the scaled solutions deviated when the soil profile was initially wet in the infiltration case or when deeply wet in the drainage condition. Based on the PM, a Philip-type model was also developed to approximate RE solutions for the constant-head infiltration. The model showed a good agreement with the scaled RE for the same range of soils and conditions...

Equation for the solvent activity correlation in ternary electrolyte solutions

Ricardini, Andres; Passamonti, Francisco Javier; Chialvo, Abel Cesar
Fonte: Elsevier Publicador: Elsevier
Tipo: info:eu-repo/semantics/article; info:ar-repo/semantics/artículo; info:eu-repo/semantics/publishedVersion Formato: application/pdf
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An analytical equation is proposed for the dependence on composition of the solvent activity of aqueous ternary electrolyte solutions. This equation was derived taking into account the limiting behaviour that must obey the solvent activity in order to be thermodynamically consistent. The correlation of experimental data corresponding to 23 ternary systems was successfully carried out. The results obtained demonstrate an excellent fitting capability of the proposed equation.; Fil: Ricardini, Andres. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico - CONICET - Santa Fe. Instituto de Investigaciones en Catálisis y Petroquímica; Argentina;; Fil: Passamonti, Francisco Javier. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico - CONICET - Santa Fe. Instituto de Investigaciones en Catálisis y Petroquímica; Argentina;; Fil: Chialvo, Abel Cesar. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico - CONICET - Santa Fe. Instituto de Investigaciones en Catálisis y Petroquímica; Argentina;

Simulation of a typical house in the region of Antananarivo, Madagascar. Determination of passive solutions using local materials

Razanamanampisoa, Harimalala; Randriamanantany, Zely Arivelo; Rakotondramiarana, Hery Tiana; Garde, François; Boyer, Harry
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 10/05/2013 Português
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This paper deals with new proposals for the design of passive solutions adapted to the climate of the highlands of Madagascar. While the strongest population density is located in the central highlands, the problem of thermal comfort in buildings occurs mainly during winter time. Currently, people use raw wood to warm the poorly designed houses. This leads to a large scale deforestation of the areas and causes erosion and environmental problems. The methodology used consisted of the identification of a typical building and of a typical meteorological year. Simulations were carried out using a thermal and airflow software (CODYRUN) to improve each building component (roof, walls, windows, and soil) in such a way as to estimate the influence of some technical solutions on each component in terms of thermal comfort. The proposed solutions also took into account the use of local materials and the standard of living of the country.

Construction of String Solutions around Non-trivial Backgrounds

Kounnas, Costas
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 14/02/1993 Português
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We present a way of constructing string solutions around non-trivial gravitational backgrounds. The proposed solutions are constructed using $N = 4$ superconformal building blocks with $\hat c = 4$. We give two different and inequivalent realizations of non-trivial four-dimensional subspaces, and we show the emergence of the $N = 4$ globally defined superconformal symmetry. The existence of $N = 4$ world-sheet symmetry stabilizes our solutions and implies in target space a number of covariantized supersymmetries around space-time dependent gravitational and dilaton backgrounds.; Comment: Latex file, 15pp, CERN-TH.6790/93

A Hypothesis for determining the maximum viscosity of sodium carboxymethylcellulose in solutions of divalent cations of high ionic strength

Lorenz, Therese
Fonte: Rochester Instituto de Tecnologia Publicador: Rochester Instituto de Tecnologia
Tipo: Tese de Doutorado
Português
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A hypothesis for deterrnining the maximum viscosity of sodium carboxymethylcellulose (or CMC) in salt solutions with respect to the concentration of CMC, the ionic strength and the cation size of the salts is proposed. The viscosity behavior of sodium carboxymethylcellulose in high ionic strength solutions was studied by varying the concentration of the CMC and the type of counterion. The object of this series of two experiments was to determine the effect of valency, cation size and ionic strength on the viscosity of CMC in high ionic strength solutions. The viscosity data in this study suggest some trends with regard to the effect of ionic strength and concentration of CMC on the viscosity behavior of CMC in solution which have been previously unreported. Additionally, some of the samples exhibited characterisitics which suggest the possibility of gelation or crosslinking of the polymer.

Thermodynamic approach for optimal design of heat and power plants: Relationships between thermodynamic and economics solutions

Mussati,S. F.; Aguirre,P. A.; Scenna,N. J.
Fonte: Latin American applied research Publicador: Latin American applied research
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/10/2006 Português
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In this paper, a new procedure for the design and analysis of Heat and Power Plants is presented. In this formulation, thermodynamic solutions obtained by maximizing the plant efficiency are used to find the economic design of the plant. In fact, by applying the Karush-Kuhn-Tucker conditions it is possible to relate thermodynamic and economic solutions. A formal context for the use of thermodynamic models in solving complex optimization problems that arise in the area of synthesis and design of chemical processes is introduced. The proposed methodology has been successfully applied for two plant arrangements. Rigorous models have been used to model the plant equipments. The obtained results are presented in order to illustrate the proposed procedure.

Approximate solutions for HIV-1 infection dynamics with cure rate

Vazquez-Leal,H.; Boubaker,K.; Marin-Hernandez,A.; Huerta-Chua,J.
Fonte: Universidad de La Salle Bajío A. C., Coordinación de Investigación Publicador: Universidad de La Salle Bajío A. C., Coordinación de Investigación
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/01/2015 Português
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In this paper, two approximate solutions of HIV-1 infection dynamics model with cure rate are presented. The proposed solutions are obtained using homotopy perturbation method (HPM) and Boubaker Polynomials expansion scheme (BPES). A comparison of obtained solutions shows that HPM and BPES are powerful tools to solve nonlinear host viral infection models.