Optimization in Eugenol Production from Clove Oil with Saponification – Neutralization Process by using Response Surface Methods

The objective of this research was to obtain optimum condition in eugenol production from clove oil with response surface methods. Clove oil was founded from essential oil cluster in Batang district Central Java. The eugenol was produced with saponification and neutralization process. Eugenol was obtained with vacuum distillation. Eugenol concentration was analyzed with gas chromatography. In this research, the variable was studied are temperature and ratio of sodium hydroxide to clove oil and yield of eugenol as response variable. So the results was obtain in minimum condition with yield of eugenol 39.17% at X 1 = -0,0109 and X 2 = 0.3095 with determinant coefficient 0.764

Optimisation of Ultra-High-Performance Concrete with Special Quarry Dust

The cement composition of concrete directly affects the CO2 emissions to the environment. UHPC (Ultra High-Performance Concrete) is a new type of concrete rapidly gaining popularity in the building industry due to its superior strength and endurance. In contrast to regular concrete, UHPC requires more than twice as much cement, making it more expensive and leaving a more significant carbon imprint. In this study, waste cement was substituted with 4%, 8%, and 12% special quarry dust from a manufacturer in Kuantan, Malaysia. Maximum compressive strength and quarry dust percentage are determined through experimentation and assessed in Design Expert Software. This investigation tested modified UHPC for strength, durability, and scanning electron microscope (SEM) appearance. Experiments show that substituting 21% quarry dust for cement yields the best outcomes. Since the particle size of quarry dust is finer than that of other matrices, it helps to reduce voids and boosts the UHPC's endurances. The quarry dust adds filler and a minor increase in viscosity to the UHPC, which is a better replacement for anhydrate cement in filler applications

Optimisation of Ultra-High-Performance Concrete with Special Quarry Dust

The cement composition of concrete directly affects the CO2 emissions to the environment. UHPC (Ultra High-Performance Concrete) is a new type of concrete rapidly gaining popularity in the building industry due to its superior strength and endurance. In contrast to regular concrete, UHPC requires more than twice as much cement, making it more expensive and leaving a more significant carbon imprint. In this study, waste cement was substituted with 4%, 8%, and 12% special quarry dust from a manufacturer in Kuantan, Malaysia. Maximum compressive strength and quarry dust percentage are determined through experimentation and assessed in Design Expert Software. This investigation tested modified UHPC for strength, durability, and scanning electron microscope (SEM) appearance. Experiments show that substituting 21% quarry dust for cement yields the best outcomes. Since the particle size of quarry dust is finer than that of other matrices, it helps to reduce voids and boosts the UHPC's endurances. The quarry dust adds filler and a minor increase in viscosity to the UHPC, which is a better replacement for anhydrate cement in filler applications

Probabilistic Reliability Analysis of Carbon/Carbon Composite Nozzle Cones with Uncertain Parameters

A methodology to perform the probabilistic and reliability-based design of a novel carbon/carbon rocket nozzle subjected to operational thermal and mechanical loads is described in this paper. In this methodology, the nozzle is represented by a multiphysics finite element model capable of predicting the temperature and stress fields of the exit cone. The analysis shows that the most likely failure modes of the exit cone are related to compressive stress along the axial and hoop directions, as well as interlaminar shear. The probabilistic models used in this methodology account for the uncertainty of the material properties by using uniform and normal distributions and different variances. The reliability analysis is performed by using surface response methods. A global sensitivity analysis is also carried out using polynomial expansion chaos surface response models. A particular novelty of the analysis is the use of Sobol indices to rank the importance of the single uncertain parameters in the models. The methodology provides a high level of confidence and robustness in determining that the axial thermal conductivity of the carbon/carbon material is the most critical material property to affect the three main failure modes, whereas the coefficient of the thermal expansion and the heat capacity play a very marginal role

Dam Safety. Overtopping and Geostructural Risks

This reprintshows recent advances in dam safety related to overtopping and the prevention, detection, and risk assessment of geostructural risks. Related to overtopping, the issues treated are: the throughflow and failure process of rockfill dams; the protection of embankment dams against overtopping by means of a rockfill toe or wedge-shaped blocks; and the protection of concrete dams with highly convergent chutes. In the area of geostructural threats, the detection of anomalies in dam behavior from monitoring data using a combination of machine learning techniques, the numerical modeling of seismic behavior of concrete dams, and the determination of the impact area downstream of ski-jump spillways are also studied and discussed. In relation to risk assessment, three chapters deal with the development of fragility curves for dikes and dams in relation to various failure mechanisms

An investigation of bicomponent polypropylene/poly(ethylene terephthalate) melt blown microfiber nonwovens

As mono-component melt blown (MB) nonwovens are finding more applications in filtration, absorbency, hygiene, and apparel, bicomponent (bico) MB nonwovens with side-by-side (S/S) cross-sectional fiber geometry are attracting significant attention from both industries and academic institutions. The S/S bico fiber provides the possibility to combine the advantages of the two polymers to produce unique fiber and web properties, such as greater fiber crimp, when the two polymers provide different shrinking behavior under heat. This work studied polypropylene/poly(ethylene terephthalate) (PP/PET) bico MB microfiber nonwovens, including the effects of processing conditions on fiber and web properties, process/structure/property relationships, and spinline dynamics. It was conducted in the 24-inch Reicofil® MB pilot line with bicomponent MB capability

Optimization of thin sheet structures with patterns perforations

Mestrado em Engenharia MecânicaNowadays, metal storage systems are generally used in industrial companies. The several stages of the metallic structures design are based in the standard EN 15512:2009. However, this standard do not the most efficient design solution, only design constraints. In this work, it is intended to improve the structural elements that are on the base of the metal storage systems, particularly shelves, in order to reduce costs and increase the structure stiffness, enforcing the international standard that define the characteristics of these products. The main purpose is the optimization of a representative section of profiled steel component taking into account the variable thickness, geometry and number of perforations. In order to do this a computational finite element model is developed and pre-­‐validated, replacing a numerous set of experimental tests in a design of Experiments (DoE) methodology. The optimized solutions were obtained through a response surface optimization methodology (RSM). The final results were analysed and discussed.Hoje em dia, os sistemas metálicos de armazenamento são vulgarmente utilizados pela indústria. As várias etapas de projeto destas estruturas metálicas são baseadas na norma EN 15512:2009. No entanto, esta norma não propõe a solução de projeto mais eficiente, apenas as suas restrições. Neste trabalho, pretende-­‐se aperfeiçoar os elementos estruturais que estão na base dos sistemas de armazenamento de metal, particularmente prateleiras, a fim de reduzir custos e aumentar a rigidez da estrutura, satisfazendo a norma internacional que define as características necessárias desses produtos. O objetivo principal é a otimização de uma secção representativa do componente de aço perfilado tendo em conta as variáveis espessura, geometria e número de perfurações. Para isso, é desenvolvido e validado um modelo computacional de elementos finitos, substituindo um numeroso conjunto de testes experimentais numa metodologia de Design of Experiments (DoE). As soluções otimizadas são obtidas através de uma metodologia de otimização baseada numa superfície de resposta (RSM). Os resultados finais são analisados e discutidos

Propriedades funcionais de sorvete de morango diet com adição da enzima lactase e transglutaminase otimizada através da metodologia de superfície de resposta

Tese (doutorado) - Universidade Federal de Santa Catarina, Centro de Ciências Agrárias, Programa de Pós-Graduação em Ciência dos Alimentos, Florianópolis, 2014.O sorvete é um sistema coloidal complexo composto por uma emulsão constituída de gotículas de gordura, proteínas, bolhas de ar e de cristais dispersos em uma fase aquosa. O produto desejado deve ter alto overrun (aeração), textura macia, baixa taxa de derretimento e poucos cristais e açúcar, obtido pela aplicação das enzimas, uma alternativa inovadora e funcional na fabricação de sorvetes. Nesta pesquisa objetivou-se otimizaras condições operacionais da produção de sorvete diet de morango pela adição de ingredientes (concentrado proteico de soro de leite e edulcorantes) e das enzimas lactase e transglutaminase, utilizando a metodologia de superfície de resposta para avaliar seus efeitos sob diferentes parâmetros físico-químicos (overrun, textura, taxa de derretimento e formação de cristais) e químicos (lactose e proteínas) na formulação do sorvete. A enzima lactase ß-galactosidase (EC. 3.2.1.23) é a responsável pela hidrólise de ligações ß-galactosídicas da lactose, resultando em sua redução pela conversão em glicose e galactose. Já a enzima transglutaminase (EC 2.3.2.13) apresenta a capacidade de catalisar reações de transferência de grupos acil, formando ligações cruzadas (intra e intermoleculares) entre proteínas, peptídeos e aminas primárias, principalmente ligações covalentes entre resíduos de glutamina e lisina (ligações G-L), aumentando a fração das proteínas de alta massa molar. Portanto, o objetivo deste trabalho foi avaliar pelo planejamento experimental central composto as condições ideais de temperatura e concentração de transglutaminase e lactase, visando a uma formulação de sorvete diet com características físico-químicas adequadas, considerando ainda as propriedades microbiológicas e sensoriais. Para tanto, foram preparadas 18 formulações de sorvetes por processo descontínuo empregando diferentes concentrações das enzimas e temperaturas de incubação, segundo delineamento fatorial 23, com quatro repetições no ponto central, para averiguar o efeito das enzimas na qualidade do sorvete. Foram realizadas determinações de: overrun, textura, índice de derretimento, reação de polimerização das proteínas do soro de leite pela formação de bandas de proteinas, hidrólise da lactose e enumerações de cristais. Nas análises estatísticas dos resultados das superfícies de contorno empregou-se a análise de variância (ANOVA), seguida do teste de Tukey em 5% de probabilidade para todos os tratamentos. A formação de cristais nos sorvetes foi verificada utilizando ANOVA unicaldal, seguida do teste de Kruskal-Wallis (não paramétrico) e do pós-teste de Dunn comparando todos os tratamentos, em nível de significância de 5%. O planejamento experimental e a análise de desejabilidade auxiliaram-na escolha do tratamento 2 como ideal, empregando as enzimas lactase (0,4 g L-1) e transglutaminase (2,0 U g-1 proteína) a 40 oC. Este foi o tratamento que apresentou melhor textura; alto overrun; menor índice de derretimento; formação de bandas de eletroforese de proteínas de alta massa molar evidenciando a formação de polímeros por ligações cruzadas pela ação da enzima transglutaminase; e a atuação mais eficiente da enzima lactase, avaliada pela hidrólise da lactose por determinação cromatográfica, confirmados pela formação de pequenos cristais e açúcar, observados pela micrografia, contribuindo para uma textura mais lisa. Pela análise sensorial, o sorvete elaborado em tais condições foi o que obteve maior aceitabilidade entre os provadores não treinados. Dessa forma, a adição das enzimas lactase e transglutaminase produziu melhora nas propriedades de textura, pelo aumento da cremosidade e suavidade, produzindo um alimento funcional com maior digestibilidade e menos calorias.Abstract : Ice cream is a complex colloidal system comprised of an emulsion consisting of fat droplets, proteins, air bubbles and crystals dispersed in an aqueous phase. The desired product should have a high overrun (degree of aeration), soft texture, slow melting rate and a low amount of crystals and sugar, obtained through the application of enzymes, an innovative and functional alternative used in the production of ice creams. The aim of this research was to optimize the operational conditions for the production of diet strawberry ice cream through the addition of ingredients (milk whey protein concentrate and sweeteners) and enzymes (lactase and transglutaminase), using the response surface methodology to evaluate their effects on different physico-chemical (overrun, texture, melting rate and formation of crystals) and chemical (lactose and proteins) parameters of the ice cream formulation. The enzyme lactase (ß-galactosidase (EC 3.2.1.23) is responsible for the hydrolysis of lactose ß-galactoside bonds, resulting in their reduction through conversion to glucose and galactose. The enzyme transglutaminase (EC 2.3.2.13) is able to catalyze acyl transfer reactions, forming cross-links (intra and intermolecular) between proteins, peptides and primary amines, mainly covalent bonds between residues of glutamine and lysine (G-L bonds), increasing the fraction of proteins of high molecular mass. However, the objective of this research was to evaluate, through a central composite experimental design, the ideal conditions of temperature and transglutaminase and lactase concentrations, aimed at obtaining a diet ice cream formulation with suitable physico-chemical characteristics, considering also the microbiological and sensory properties. A total of 18 ice cream formulations were prepared by a discontinuous process employing different concentrations of enzymes and incubation temperatures, according to a 23 factorial design, with four repetitions at the central point, to investigate the effect of the enzymes on the ice cream quality. Analysis was carried out to determine the overrun, texture, melting index, milk whey protein polymerization reaction through the formation of protein bands, lactose hydrolysis and number of crystals. In the statistical analysis of the results for the response surfaces, analysis of variance (ANOVA) followed by the Tukey test (5% probability) was used for all treatments. The formation of crystals in the ice cream samples was verified using one-tailed ANOVA followed by the Kruskal-Wallis test (non-parametric) and the Dunn s post-hoc test comparing all treatments, at the 5% significance level. The experimental design and the desirability analysis aided the selection of the ideal treatment (treatment 2), in which the enzymes lactase (0.4 g L-1) and transglutaminase (2.0 U g-1 protein) and a temperature of 40 oC were employed. This was the treatment which provided the best texture, high overrun, the lowest melting index, formation of electrophoresis bands of proteins of high molecular mass evidencing the formation of polymers through cross-links due to the action of the enzyme transglutaminase and the most efficient action of the enzyme lactase, evaluated through the lactose hydrolysis determined by chromatography, verified by the formation of small crystals and sugar, observed on themicrograph, contributing to a smoother texture. The sensory analysis indicated that the ice cream prepared under these conditions had the greatest acceptability according to the untrained tasters. Thus, the addition of the enzymes lactase and transglutaminase improved the textural properties by increasing the creaminess and smoothness, producing a functional food with greater digestibility and reduced calories

Experimental and Chemical Kinetic Modelling Study on the Combustion of Alternative Fuels in Fundamental Systems and Practical Engines

In this work, experimental data of ignition delay times of n-butanol, gasoline, toluene reference fuel (TRF), a gasoline/n-butanol blend and a TRF/n-butanol blend were obtained using the Leeds University Rapid Compression Machine (RCM) while autoignition (knock) onsets and knock intensities of gasoline, TRF, gasoline/n-butanol and TRF/n-butanol blends were measured using the Leeds University Optical Engine (LUPOE). The work showed that within the RCM, the 3-component TRF surrogate captures the trend of gasoline data well across the temperature range. However, based on results obtained in the engine, it appears that the chosen TRF may not be an excellent representation of gasoline under engine conditions as the knock boundary of TRF as well as the measured knock onsets are significantly lower than those of gasoline. The ignition delay times measured in the RCM for the blend, lay between those of gasoline and n-butanol under stoichiometric conditions across the temperature range studied and at lower temperatures, n-butanol acts as an octane enhancer over and above what might be expected from a simple linear blending law. In the engine, the measured knock onsets for the blend were higher than those of gasoline at the more retarded spark timing of 6 CA bTDC but the effect disappears at higher spark advances. Future studies exploring the blending effect of n-butanol across a range of blending ratios is required since it is difficult to conclude on the overall effect of n-butanol blending on gasoline based on the single blend that has been considered in this study. The chemical kinetic modelling of the fuels investigated has also been evaluated by comparing results from simulations employing the relevant reaction mechanisms with the experimental data sourced from either the open literature or measured in-house. Local as well as global uncertainty/sensitivity methods accounting for the impact of uncertainties in the input parameters, were also employed within the framework of ignition delay time modelling in an RCM and species concentration prediction in a JSR, for analysis of the chemical kinetic modelling of DME, n-butanol, TRF and TRF/n-butanol oxidation in order to advance the understanding of the key reactions rates that are crucial for the accurate prediction of the combustion of alternative fuels in internal combustion engines. The results showed that uncertainties in predicting key target quantities for the various fuels studied are currently large but driven by few reactions. Further studies of the key reaction channels identified in this work at the P-T conditions of relevance to combustion applications could help to improve current mechanisms. Moreover, the chemical kinetic modelling of the autoignition and species concentration of TRF, TRF/n-butanol and n-butanol fuels was carried out using the adopted TRF/n-butanol mechanism as input in the engine simulations of a recently developed commercial engine software known as LOGEengine. Similar to the results obtained in the RCM modelling work, the knock onsets predicted for TRF and TRF/n-butanol blend under engine conditions were consistently higher than the measured data. Overall, the work demonstrated that accurate representation of the low temperature chemistry in current chemical kinetic models of alternative fuels is very crucial for the accurate description of the chemical processes and autoignition of the end gas in the engine