Surface esterification of cellulose fibres: Processing and characterisation of low-density polyethylene/cellulose fibres composites

Low-density polyethylene was filled with cellulose fibres from sugar cane bagasse obtained from organosolv/supercritical carbon dioxide pulping process. The fibres were also used after chemical modification with octadecanoyl and dodecanoyl chloride acids. The morphology, thermal properties, mechanical properties in both the linear and nonlinear range, and the water absorption behaviour of ensuing composites were tested. The evidence of occurrence of the chemical modification was checked by X-ray photoelectron spectrometry. The degree of polymerisation of the fibres and their intrinsic properties (zero tensile strength) were determined. It clearly appeared that the surface chemical modification of cellulose fibres resulted in improved interfacial adhesion with the matrix and higher dispersion level. However, composites did not show improved mechanical performances when compared to unmodified fibres. This surprising result was ascribed to the strong lowering of the degree of polymerisation of cellulose fibres (as confirmed by the drastic decrease of their zero tensile strength) after chemical treatment despite the mild conditions used. (c) 2007 Elsevier Ltd. All rights reserved.

Signal Processing and patternrecognition algorithm for monitoringParkinson’s disease.

This masters thesis describes the development of signal processing and patternrecognition in monitoring Parkison’s disease. It involves the development of a signalprocess algorithm and passing it into a pattern recogniton algorithm also. Thesealgorithms are used to determine , predict and make a conclusion on the study ofparkison’s disease. We get to understand the nature of how the parkinson’s disease isin humans.

Road network and GPS tracking with data processing and quality assessment

GPS technology has been embedded into portable, low-cost electronic devices nowadays to track the movements of mobile objects. This implication has greatly impacted the transportation field by creating a novel and rich source of traffic data on the road network. Although the promise offered by GPS devices to overcome problems like underreporting, respondent fatigue, inaccuracies and other human errors in data collection is significant; the technology is still relatively new that it raises many issues for potential users. These issues tend to revolve around the following areas: reliability, data processing and the related application. This thesis aims to study the GPS tracking form the methodological, technical and practical aspects. It first evaluates the reliability of GPS based traffic data based on data from an experiment containing three different traffic modes (car, bike and bus) traveling along the road network. It then outline the general procedure for processing GPS tracking data and discuss related issues that are uncovered by using real-world GPS tracking data of 316 cars. Thirdly, it investigates the influence of road network density in finding optimal location for enhancing travel efficiency and decreasing travel cost. The results show that the geographical positioning is reliable. Velocity is slightly underestimated, whereas altitude measurements are unreliable.Post processing techniques with auxiliary information is found necessary and important when solving the inaccuracy of GPS data. The densities of the road network influence the finding of optimal locations. The influence will stabilize at a certain level and do not deteriorate when the node density is higher.

Essays on decision sciences: exploring cognition, information processing, and complexity

This thesis provides three original contributions to the field of Decision Sciences. The first contribution explores the field of heuristics and biases. New variations of the Cognitive Reflection Test (CRT--a test to measure "the ability or disposition to resist reporting the response that first comes to mind"), are provided. The original CRT (S. Frederick [2005] Journal of Economic Perspectives, v. 19:4, pp.24-42) has items in which the response is immediate--and erroneous. It is shown that by merely varying the numerical parameters of the problems, large deviations in response are found. Not only the final results are affected by the proposed variations, but so is processing fluency. It seems that numbers' magnitudes serve as a cue to activate system-2 type reasoning. The second contribution explores Managerial Algorithmics Theory (M. Moldoveanu [2009] Strategic Management Journal, v. 30, pp. 737-763); an ambitious research program that states that managers display cognitive choices with a "preference towards solving problems of low computational complexity". An empirical test of this hypothesis is conducted, with results showing that this premise is not supported. A number of problems are designed with the intent of testing the predictions from managerial algorithmics against the predictions of cognitive psychology. The results demonstrate (once again) that framing effects profoundly affect choice, and (an original insight) that managers are unable to distinguish computational complexity problem classes. The third contribution explores a new approach to a computationally complex problem in marketing: the shelf space allocation problem (M-H Yang [2001] European Journal of Operational Research, v. 131, pp.107--118). A new representation for a genetic algorithm is developed, and computational experiments demonstrate its feasibility as a practical solution method. These studies lie at the interface of psychology and economics (with bounded rationality and the heuristics and biases programme), psychology, strategy, and computational complexity, and heuristics for computationally hard problems in management science.

Number Processing and Calculation in Brazilian Children Aged 7-12 Years

Numerical cognition is based on two components - number processing and calculation. Its development is influenced by biological, cognitive, educational, and cultural factors. The objectives of the present study were to: i) assess number processing and calculation in Brazilian children aged 7-12 years from public schools using the Zareki-R (Battery of neuropsychological tests for number processing and calculation in children, Revised; von Aster & Dellatolas, 2006) in order to obtain normative data for Portuguese speakers; ii) identify how environment, age, and gender influences the development of these mathematical skills; iii) investigate the construct validity of the Zareki-R by the contrast with the Arithmetic subtest of WISC-III. The sample included 172 children, both genders, divided in two groups: urban (N= 119) and rural (N= 53) assessed by the Zareki-R. Rural children presented lower scores in one aspect of number processing; children aged 7-8 years demonstrated an inferior global score than older; boys presented a superior performance in both number processing and calculation. Construct validity of Zareki-R was demonstrated by high to moderate correlations with Arithmetic subtest of WISC-III. The Zareki-R therefore is a suitable instrument to assess the development of mathematical skills, which is influenced by factors such as environment, age, and gender.

Processing and hygrothermal effects on viscoelastic behavior of glass fiber/epoxy composites

Fiber reinforced epoxy composites are used in a wide variety of applications in the aerospace field. These materials have high specific moduli, high specific strength and their properties can be tailored to application requirements. In order to screening optimum materials behavior, the effects of external environments on the mechanical properties during usage must be clearly understood. The environmental action, such as high moisture concentration, high temperatures, corrosive fluids or ultraviolet radiation (UV), can affect the performance of advanced composites during service. These factors can limit the applications of composites by deteriorating the mechanical properties over a period of time. Properties determination is attributed to the chemical and/or physical damages caused in the polymer matrix, loss of adhesion of fiber/resin interface, and/or reduction of fiber strength and stiffness. The dynamic elastic properties are important characteristics of glass fiber reinforced composites (GRFC). They control the damping behavior of composite structures and are also an ideal tool for monitoring the development of GFRC's mechanical properties during their processing or service. One of the most used tests is the vibration damping. In this work, the measurement consisted of recording the vibration decay of a rectangular plate excited by a controlled mechanism to identify the elastic and damping properties of the material under test. The frequency amplitude were measured by accelerometers and calculated by using a digital method. The present studies have been performed to explore relations between the dynamic mechanical properties, damping test and the influence of high moisture concentration of glass fiber reinforced composites (plain weave). The results show that the E' decreased with the increase in the exposed time for glass fiber/epoxy composites specimens exposed at 80 degrees C and 90% RH. The E' values found were: 26.7, 26.7, 25.4, 24.7 and 24.7 GPa for 0, 15, 30, 45 and 60 days of exposure, respectively. (c) 2005 Springer Science + Business Media, Inc.

Identification of Landslide Scars in the Region of the Serra do Mar, São Paulo State, Brazil, Using Digital Image Processing and Spatial Analysis Tools

The objective of the present study, developed in a mountainous region in Brazil where many landslides occur, is to present a method for detecting landslide scars that couples image processing techniques with spatial analysis tools. An IKONOS image was initially segmented, and then classified through a Batthacharrya classifier, with an acceptance limit of 99%, resulting in 216 polygons identified with a spectral response similar to landslide scars. After making use of some spatial analysis tools that took into account a susceptibility map, a map of local drainage channels and highways, and the maximum expected size of scars in the study area, some features misinterpreted as scars were excluded. The 43 resulting features were then compared with visually interpreted landslide scars and field observations. The proposed method can be reproduced and enhanced by adding filtering criteria and was able to find new scars on the image, with a final error rate of 2.3%.

Processing and properties of Ag/BSCCO PIT tapes containing different proportions of silver metal powder

Monofilamentary tapes (150 pm thickness) were prepared by swaging and rolling silver tubes containing the Bi:2212 ceramic (granulation below 20 mum) and the silver powder (about 0.8 mum). The study has been made, among other samples, on tapes with nominal proportions of 0, 10 and 20 wt.% of silver. The samples were characterized by SEM, and by electrical measurements under varying applied magnetic field. The measurements of J(c) showed that the addition of 10 wt.% silver powder is very beneficent to this property, doubling the obtained values at 60 K, while the 20 wt.% tape presented very low J(c). The tape with no silver content showed to have a J(c) as high as 2.2 x 10(5) A/cm(2), at 4.2 K, zero applied magnetic field. (C) 2004 Elsevier B.V. All rights reserved.

PROCESSING AND CHARACTERIZATION OF LOW-VOLTAGE VARISTORS

ZnO seed particles and Cr2O3 were used in this study to control the microstructure of ZnO varistors. The seed particles were prepared by adding 1.0 mol % BaO to ZnO. The powder was then calcined at 800-degrees-C for 2 h, pressed into pellets and sintered at 1400-degrees-C for 8 h. The sintered ZnO was ground and the BaO eliminated by washing in water. The remaining ZnO powder was classified into a size fraction ranging from 38 to 149 mum. The addition of a small amount (1 weight %) ZnO seed grains produces varistors with low breakdown voltages (7.6 V/mm) and an alpha coefficient of approximately 10. The addition of Cr2O3 stabilizes the spinel phase yielding a more homogeneous microstructure, but degraded electrical behaviour of the ZnO varistor.

Joint rolling-horizon scheduling of materials processing and lot-sizing with sequence-dependent setups

A lot sizing and scheduling problem from a foundry is considered in which key materials are produced and then transformed into many products on a single machine. A mixed integer programming (MIP) model is developed, taking into account sequence-dependent setup costs and times, and then adapted for rolling horizon use. A relax-and-fix (RF) solution heuristic is proposed and computationally tested against a high-performance MIP solver. Three variants of local search are also developed to improve the RF method and tested. Finally the solutions are compared with those currently practiced at the foundry.

Processing and mechanical characterization of titanium-graphite hybrid laminates

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Fibre analysis and fibre digestibility in pet foods - a comparison of total dietary fibre, neutral and acid detergent fibre and crude fibre

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Powder processing and In Vivo evaluation of a titanium porous coating implant

The processing of titanium porous coatings using powder metallurgy technique to achieve a porous structure that allows osseointegration with bone tissue was discussed. The porous microstructure exhibited micropores and interconnected macropores with size ranges that allowed bone ingrowth. The macropores in the coatings were originated from the binder evaporation while the micropore was related with the porous titanium powder and the low compaction pressure used. The in vivo evaluation indicated that osseointegration had occurred between the bone and porous material.

A priori reformulations for joint rolling-horizon scheduling of materials processing and lot-sizing problem

In many production processes, a key material is prepared and then transformed into different final products. The lot sizing decisions concern not only the production of final products, but also that of material preparation in order to take account of their sequence-dependent setup costs and times. The amount of research in recent years indicates the relevance of this problem in various industrial settings. In this paper, facility location reformulation and strengthening constraints are newly applied to a previous lot-sizing model in order to improve solution quality and computing time. Three alternative metaheuristics are used to fix the setup variables, resulting in much improved performance over previous research, especially regarding the use of the metaheuristics for larger instances. © 2013 Elsevier Ltd. All rights reserved.

Processing and characterization of extruded breakfast meal formulated with broken rice and bean flour

O objetivo deste trabalho foi elaborar um produto matinal extrusado de quirera de arroz e bandinha de feijão, além de verificar a influência do processo de extrusão nas suas características físico-químicas, nutricionais, tecnológicas e sensoriais. O produto final apresentou teor considerável de proteínas (9,9 g.100 g^-1), podendo ser considerado uma boa fonte desse nutriente para crianças e adolescentes. Para a fibra alimentar, observou-se teor de 3,71 g.100 g^-1 do produto pronto para o consumo. Dessa forma, o floco matinal de arroz e feijão pode receber a alegação de alimento fonte de fibras, de acordo com a legislação brasileira. Com relação às propriedades tecnológicas, o extrusado estudado apresentou índice de expansão de 8,89 e densidade aparente de 0,25 g.cm^-3. Quanto à análise sensorial, o floco matinal avaliado obteve notas médias de aceitação, situadas no intervalo de 6,8 a 7,7, que corresponde às categorias "gostei ligeiramente" e "gostei muito". Para a intenção de compra, 79% dos provadores opinaram que certamente ou possivelmente comprariam o produto. O emprego de quirera de arroz e bandinha de feijão é uma interessante alternativa para a elaboração de produto matinal extrusado, apresentando boas qualidades de ordem nutricional, tecnológica e sensorial.