Empirical and fundamental mechanical tests in the evaluation of dough and bread rheological properties

Bread dough and particularly wheat dough, due to its viscoelastic behaviour, is probably the most dynamic and complicated rheological system and its characteristics are very important since they highly affect final products’ textural and sensorial properties. The study of dough rheology has been a very challenging task for many researchers since it can provide numerous information about dough formulation, structure and processing. This explains why dough rheology has been a matter of investigation for several decades. In this research rheological assessment of doughs and breads was performed by using empirical and fundamental methods at both small and large deformation, in order to characterize different types of doughs and final products such as bread. In order to study the structural aspects of food products, image analysis techniques was used for the integration of the information coming from empirical and fundamental rheological measurements. Evaluation of dough properties was carried out by texture profile analysis (TPA), dough stickiness (Chen and Hoseney cell) and uniaxial extensibility determination (Kieffer test) by using a Texture Analyser; small deformation rheological measurements, were performed on a controlled stress–strain rheometer; moreover the structure of different doughs was observed by using the image analysis; while bread characteristics were studied by using texture profile analysis (TPA) and image analysis. The objective of this research was to understand if the different rheological measurements were able to characterize and differentiate the different samples analysed. This in order to investigate the effect of different formulation and processing conditions on dough and final product from a structural point of view. For this aim the following different materials were performed and analysed: - frozen dough realized without yeast; - frozen dough and bread made with frozen dough; - doughs obtained by using different fermentation method; - doughs made by Kamut® flour; - dough and bread realized with the addition of ginger powder; - final products coming from different bakeries. The influence of sub-zero storage time on non-fermented and fermented dough viscoelastic performance and on final product (bread) was evaluated by using small deformation and large deformation methods. In general, the longer the sub-zero storage time the lower the positive viscoelastic attributes. The effect of fermentation time and of different type of fermentation (straight-dough method; sponge-and-dough procedure and poolish method) on rheological properties of doughs were investigated using empirical and fundamental analysis and image analysis was used to integrate this information throughout the evaluation of the dough’s structure. The results of fundamental rheological test showed that the incorporation of sourdough (poolish method) provoked changes that were different from those seen in the others type of fermentation. The affirmative action of some ingredients (extra-virgin olive oil and a liposomic lecithin emulsifier) to improve rheological characteristics of Kamut® dough has been confirmed also when subjected to low temperatures (24 hours and 48 hours at 4°C). Small deformation oscillatory measurements and large deformation mechanical tests performed provided useful information on the rheological properties of samples realized by using different amounts of ginger powder, showing that the sample with the highest amount of ginger powder (6%) had worse rheological characteristics compared to the other samples. Moisture content, specific volume, texture and crumb grain characteristics are the major quality attributes of bread products. The different sample analyzed, “Coppia Ferrarese”, “Pane Comune Romagnolo” and “Filone Terra di San Marino”, showed a decrease of crumb moisture and an increase in hardness over the storage time. Parameters such as cohesiveness and springiness, evaluated by TPA that are indicator of quality of fresh bread, decreased during the storage. By using empirical rheological tests we found several differences among the samples, due to the different ingredients used in formulation and the different process adopted to prepare the sample, but since these products are handmade, the differences could be account as a surplus value. In conclusion small deformation (in fundamental units) and large deformation methods showed a significant role in monitoring the influence of different ingredients used in formulation, different processing and storage conditions on dough viscoelastic performance and on final product. Finally the knowledge of formulation, processing and storage conditions together with the evaluation of structural and rheological characteristics is fundamental for the study of complex matrices like bakery products, where numerous variable can influence their final quality (e.g. raw material, bread-making procedure, time and temperature of the fermentation and baking).

Monetary Policy, Stock Price Misalignments and Macroeconomic Instability

Perhaps the most fundamental prediction of financial theory is that the expected returns on financial assets are determined by the amount of risk contained in their payoffs. Assets with a riskier payoff pattern should provide higher expected returns than assets that are otherwise similar but provide payoffs that contain less risk. Financial theory also predicts that not all types of risks should be compensated with higher expected returns. It is well-known that the asset-specific risk can be diversified away, whereas the systematic component of risk that affects all assets remains even in large portfolios. Thus, the asset-specific risk that the investor can easily get rid of by diversification should not lead to higher expected returns, and only the shared movement of individual asset returns – the sensitivity of these assets to a set of systematic risk factors – should matter for asset pricing. It is within this framework that this thesis is situated. The first essay proposes a new systematic risk factor, hypothesized to be correlated with changes in investor risk aversion, which manages to explain a large fraction of the return variation in the cross-section of stock returns. The second and third essays investigate the pricing of asset-specific risk, uncorrelated with commonly used risk factors, in the cross-section of stock returns. The three essays mentioned above use stock market data from the U.S. The fourth essay presents a new total return stock market index for the Finnish stock market beginning from the opening of the Helsinki Stock Exchange in 1912 and ending in 1969 when other total return indices become available. Because a total return stock market index for the period prior to 1970 has not been available before, academics and stock market participants have not known the historical return that stock market investors in Finland could have achieved on their investments. The new stock market index presented in essay 4 makes it possible, for the first time, to calculate the historical average return on the Finnish stock market and to conduct further studies that require long time-series of data.

Los grupos de empresas en los sectores y subsectores cotizados: la banca y cajas de ahorro

El sector Bancario y de Caja de Ahorros está compuesto por diversas entidades, y la mayoría son entidades cotizadas, pero mucha de estas entidades forman entre si grupos financieros o también denominados conglomerados financieros. Un conglomerado financiero existe cuando un grupo de compañías controladas por la misma entidad, las actividades de las entidades que lo forman se encuentran en el área financiera, pero hay al menos dos actividades distintas dentro el entrono financiero. Una vez que hemos delimitado el tipo de grupo empresarial que tenemos, pasamos a realizar un análisis fundamental, elemento que permite determinar el valor de la empresa. Usamos ratio tales como el ratio PER (Price Earning Ratio), el BPA (Beneficio Por Accion) o el Precio/Cash-Flow que nos permite emitir un valor de cotización. En España, encontramos 3 principales grupos financieros, estos son el BBVA, el Santander y CaixaBank, los cuales tienen valores de cotización distintos, mostrándonos que el BBVA, por cotización, es el mejor grupo financiero español. Mientras que si hubiésemos hecho un análisis contable, diríamos que el mejor sería el grupo Santander. Lo cual nos lleva a hacer una apreciación general, no tiene porque basarte solo en la información contable, sino que hay que tener también en cuenta elementos externos que puedan afectarnos. Trabajo realizado en Castellano.

Um circuito para a possibilidade: as revistas de poesia na década de 70

As revistas de poesia dos anos 70 são importante objeto de estudo, busca-se através delas compreender como essa produção literária articula com o conteúdo histórico-cultural, mas principalmente como a análise dessa produção é fundamental para mostrar a maneira com a qual se articulavam e se misturavam as tendências poéticas da década de 70. Para observar esse panorama foram utilizadas as revistas de poesia Navilouca, Polem, Almanaque Biotônico Vitalidade, Código e Alguma Poesia, assim como foram abordadas as principais vertentes culturais atuantes na época como tropicalismo, concretismo, arte engajada e poesia marginal. Foi traçado um panorama cultural da década de 60 e 70 e foram adicionadas questões ligadas ao mercado editorial no período e como as revistas de poesia atuam na construção da literatura como uma possibilidade de circulação da atividade poética dessa época

Grado de predicción del valor de las acciones ante nuevas emisiones en el sector de extracción de petróleo crudo y gas natural en Colombia, mediante modelos de caos y análisis recurrente

El presente trabajo se enfoca en el análisis de las acciones de Ecopetrol, empresa representativa del mercado de Extracción de Petróleo y Gas natural en Colombia (SP&G), durante el periodo, del 22 de mayo de 2012 al 30 de agosto de 2013. Durante este espacio de tiempo la acción sufrió una serie de variaciones en su precio las cuales se relacionaban a la nueva emisión de acciones que realizo la Compañía. Debido a este cambio en el comportamiento del activo se generaron una serie de interrogantes sobre, (i) la reacción del mercado ante diferentes sucesos ocurridos dentro de las firmas y en su entorno (ii) la capacidad de los modelos financieros de predecir y entender las posibles reacciones observadas de los activos (entendidos como deuda). Durante el desarrollo del presente trabajo se estudiará la pertinencia del mismo, en línea con los objetivos y desarrollos de la Escuela de Administración de la Universidad del Rosario. Puntualmente en temas de Perdurabilidad direccionados a la línea de Gerencia. Donde el entendimiento de la deuda como parte del funcionamiento actual y como variable determinante para el comportamiento futuro de las organizaciones tiene especial importancia. Una vez se clarifica la relación entre el presente trabajo y la Universidad, se desarrollan diferentes conceptos y teorías financieras que han permitido conocer y estudiar de manera más específica el mercado, con el objetivo de reducir los riesgos de las inversiones realizadas. Éste análisis se desarrolla en dos partes: (i) modelos de tiempo discreto y (ii) modelos de tiempo continúo. Una vez se tiene mayor claridad sobre los modelos estudiados hasta el momento se realiza el respectivo análisis de los datos mediante modelos de caos y análisis recurrente los cuales nos permiten entender que las acciones se comportan de manera caótica pero que establecen ciertas relaciones entre los precios actuales y los históricos, desarrollando comportamientos definidos entre los precios, las cantidades, el entorno macroeconómico y la organización. De otra parte, se realiza una descripción del mercado de petróleo en Colombia y se estudia a Ecopetrol como empresa y eje principal del mercado descrito en el país. La compañía Ecopetrol es representativa debido a que es uno de los mayores aportantes fiscales del país, pues sus ingresos se desprenden de bienes que se encuentran en el subsuelo por lo que la renta petrolera incluye impuestos a la producción transformación y consumo (Ecopetrol, 2003). Por último, se presentan los resultados del trabajo, así como el análisis que da lugar para presentar ciertas recomendaciones a partir de lo observado.

Estudo sobre orçamento de atividade do Boto Cinza (Sotalia guianensis) no litoral sul do Rio Grande do Norte

A fundamental analysis on Behavioral Ecology is the construction of Activities Budget, which can be defined as the quantification of the time that each animal uses in activities that are important for its survival and reproduction. Initially developed for theoretical studies about Optimal Foraging, the construction of Activities Budgets has recently being used for analyses in Conservation Biology. However, the measurement of behavior through an adequate methodology that allows the comparison between different samples is a challenge for researchers in the area of Ethology. This problem is even bigger for the students of cetaceans behavior due to the difficulty of visualization of these animals. The present work deals with two aspects of the specialized literature on cetaceans: i) it explores possible variations of results in quantification of behavioral states decurrent of the application of different methods of data collection, and ii) it describes the activity budget of a population of Sotalia guianensis that inhabits coastal waters, south Rio Grande do Norte. The results showed that the use different methods of data collection result in significant differences, but of small scale, in the quantification of the behavioral frequency. The activity budget of Sotalia in the area here analyzed was similar to that described for other populations of this species inhabiting typically estuarine habitats. Tide and day-hour did not influence the dolphin s behavior, however, significant differences were found related to the position of the animals within the area. These results are discussed considering the dietary and behavioral flexibility of the species, contributing to the scientific knowledge and offering information that will be useful in comparative studies and for analyses on the determination of areas for species conservation

Rugosidades étnicas e a espacialidade do preconceito racial

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Relative accuracy and predictive ability of direct valuation methods, price to aggregate earnings method and a hybrid approach

In this paper, we assess the relative performance of the direct valuation method and industry multiplier models using 41 435 firm-quarter Value Line observations over an 11 year (1990–2000) period. Results from both pricingerror and return-prediction analyses indicate that direct valuation yields lower percentage pricing errors and greater return prediction ability than the forward price to aggregated forecasted earnings multiplier model. However, a simple hybrid combination of these two methods leads to more accurate intrinsic value estimates, compared to either method used in isolation. It would appear that fundamental analysis could benefit from using one approach as a check on the other.

Some aspects of drill performance

High speed twist drills are probably the most common of all metal cutting tools and also the least efficient. In this study, detailed research was undertaken into aspects of drill performance and ways in which drilling could be improved in short hole depths of up to two diameters. The work included an evaluation of twist drill geometry and grinding parameters. It was established that errors in point grinding lead to increased hole oversize and reduced drill life. A fundamental analysis was made to establish predictive equations for the drill torque and thrust using modified orthogonal cutting equations and empirical data. A good correlation was obtained between actual and predicted results. Two new techniques for extending twist drill life by the use of coolant feeding holes and also the application of titanium nitride coatings were evaluated. Both methods were found to have potential for improving drill performance. A completely new design of carbide tipped drill was designed and developed. The new design was tested and it compared favourably with two commercially available carbide tipped drills. In further work an entirely different type of drill point geometry was developed for the drill screw. A new design was produced which enabled the drilling time to be minimised for the low thrust forces that were likely to be used with hand held power tools.

Analysis of conical-cylinder shells fundamental characteristics for structural health diagnostics

This paper describes the formulation for the free vibration of joined conical-cylindrical shells with uniform thickness using the transfer of influence coefficient for identification of structural characteristics. These characteristics are importance for structural health monitoring to develop model. This method was developed based on successive transmission of dynamic influence coefficients, which were defined as the relationships between the displacement and the force vectors at arbitrary nodal circles of the system. The two edges of the shell having arbitrary boundary conditions are supported by several elastic springs with meridional/axial, circumferential, radial and rotational stiffness, respectively. The governing equations of vibration of a conical shell, including a cylindrical shell, are written as a coupled set of first order differential equations by using the transfer matrix of the shell. Once the transfer matrix of a single component has been determined, the entire structure matrix is obtained by the product of each component matrix and the joining matrix. The natural frequencies and the modes of vibration were calculated numerically for joined conical-cylindrical shells. The validity of the present method is demonstrated through simple numerical examples, and through comparison with the results of previous researchers.

Exergetic analysis of carbon dioxide vapour compression refrigeration cycle using the new fundamental equation of state

The purpose of this paper is to present exergy charts for carbon dioxide (CO2) based on the new fundamental equation of state and the results of a thermodynamic analysis of conventional and trans-critical vapour compression refrigeration cycles using the data thereof. The calculation scheme is anchored on the Mathematica platform. There exist upper and lower bounds for the high cycle pressure for a given set of evaporating and pre-throttling temperatures. The maximum possible exergetic efficiency for each case was determined. Empirical correlations for exergetic efficiency and COP, valid in the range of temperatures studied here, are obtained. The exergy losses have been quantified. (C) 2003 Elsevier Ltd. All rights reserved.