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Auswahl der wissenschaftlichen Literatur zum Thema „Responsive extrusion“
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Zeitschriftenartikel zum Thema "Responsive extrusion"
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Pilate, Florence, Rosica Mincheva, Julien De Winter, Pascal Gerbaux, Linbo Wu, Richard Todd, Jean-Marie Raquez und Philippe Dubois. „Design of Multistimuli-Responsive Shape-Memory Polymer Materials by Reactive Extrusion“. Chemistry of Materials 26, Nr. 20 (02.10.2014): 5860–67. http://dx.doi.org/10.1021/cm5020543.
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Wang, Fan, Ling Li, Xiaolong Zhu, Feng Chen und Xiaoxiao Han. „Development of pH-Responsive Polypills via Semi-Solid Extrusion 3D Printing“. Bioengineering 10, Nr. 4 (24.03.2023): 402. http://dx.doi.org/10.3390/bioengineering10040402.
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The low bioavailability of orally administered drugs as a result of the instability in the gastrointestinal tract environment creates significant challenges to developing site-targeted drug delivery systems. This study proposes a novel hydrogel drug carrier using pH-responsive materials assisted with semi-solid extrusion 3D printing technology, enabling site-targeted drug release and customisation of temporal release profiles. The effects of material parameters on the pH-responsive behaviours of printed tablets were analysed thoroughly by investigating the swelling properties under both artificial gastric and intestinal fluids. It has been shown that high swelling rates at either acidic or alkaline conditions can be achieved by adjusting the mass ratio between sodium alginate and carboxymethyl chitosan, enabling site-targeted release. The drug release experiments reveal that gastric drug release can be achieved with a mass ratio of 1:3, whilst a ratio of 3:1 allows for intestinal release. Furthermore, controlled release is realised by tuning the infill density of the printing process. The method proposed in this study can not only significantly improve the bioavailability of oral drugs, but also offer the potential that each component of a compound drug tablet can be released in a controlled manner at a target location.
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Yanagihara, Shin, Yukiya Kitayama, Eiji Yuba und Atsushi Harada. „Preparing Size-Controlled Liposomes Modified with Polysaccharide Derivatives for pH-Responsive Drug Delivery Applications“. Life 13, Nr. 11 (03.11.2023): 2158. http://dx.doi.org/10.3390/life13112158.
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The liposome particle size is an important parameter because it strongly affects content release from liposomes as a result of different bilayer curvatures and lipid packing. Earlier, we developed pH-responsive polysaccharide-derivative-modified liposomes that induced content release from the liposomes under weakly acidic conditions. However, the liposome used in previous studies size was adjusted to 100–200 nm. The liposome size effects on their pH-responsive properties were unclear. For this study, we controlled the polysaccharide-derivative-modified liposome size by extrusion through polycarbonate membranes having different pore sizes. The obtained liposomes exhibited different average diameters, in which the diameters mostly corresponded to the pore sizes of polycarbonate membranes used for extrusion. The amounts of polysaccharide derivatives per lipid were identical irrespective of the liposome size. Introduction of cholesterol within the liposomal lipid components suppressed the size increase in these liposomes for at least three weeks. These liposomes were stable at neutral pH, whereas the content release from liposomes was induced at weakly acidic pH. Smaller liposomes exhibited highly acidic pH-responsive content release compared with those from large liposomes. However, liposomes with 50 mol% cholesterol were not able to induce content release even under acidic conditions. These results suggest that control of the liposome size and cholesterol content is important for preparing stable liposomes at physiological conditions and for preparing highly pH-responsive liposomes for drug delivery applications.
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Sui, Zhijie, und Joseph B. Schlenoff. „Phase Separations in pH-Responsive Polyelectrolyte Multilayers: Charge Extrusion versus Charge Expulsion“. Langmuir 20, Nr. 14 (Juli 2004): 6026–31. http://dx.doi.org/10.1021/la0495985.
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Aliabouzar, Mitra, Adam W. Y. Ley, Sabine Meurs, Andrew J. Putnam, Brendon M. Baker, Oliver D. Kripfgans, J. Brian Fowlkes und Mario L. Fabiilli. „Micropatterning of acoustic droplet vaporization in acoustically-responsive scaffolds using extrusion-based bioprinting“. Bioprinting 25 (März 2022): e00188. http://dx.doi.org/10.1016/j.bprint.2021.e00188.
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Ohsawa, Shizue, John Vaughen und Tatsushi Igaki. „Cell Extrusion: A Stress-Responsive Force for Good or Evil in Epithelial Homeostasis“. Developmental Cell 44, Nr. 3 (Februar 2018): 284–96. http://dx.doi.org/10.1016/j.devcel.2018.01.009.
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Ohsawa, Shizue, John Vaughen und Tatsushi Igaki. „Cell Extrusion: A Stress-Responsive Force for Good or Evil in Epithelial Homeostasis“. Developmental Cell 44, Nr. 4 (Februar 2018): 532. http://dx.doi.org/10.1016/j.devcel.2018.02.007.
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Lee, Chang-Uk, Johanna Vandenbrande, Adam E. Goetz, Mark A. Ganter, Duane W. Storti und Andrew J. Boydston. „Room temperature extrusion 3D printing of polyether ether ketone using a stimuli-responsive binder“. Additive Manufacturing 28 (August 2019): 430–38. http://dx.doi.org/10.1016/j.addma.2019.05.008.
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Hu, Chen, Lukas Hahn, Mengshi Yang, Alexander Altmann, Philipp Stahlhut, Jürgen Groll und Robert Luxenhofer. „Improving printability of a thermoresponsive hydrogel biomaterial ink by nanoclay addition“. Journal of Materials Science 56, Nr. 1 (25.09.2020): 691–705. http://dx.doi.org/10.1007/s10853-020-05190-5.
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Abstract As a promising biofabrication technology, extrusion-based bioprinting has gained significant attention in the last decade and major advances have been made in the development of bioinks. However, suitable synthetic and stimuli-responsive bioinks are underrepresented in this context. In this work, we described a hybrid system of nanoclay Laponite XLG and thermoresponsive block copolymer poly(2-methyl-2-oxazoline)-b-poly(2-n-propyl-2-oxazine) (PMeOx-b-PnPrOzi) as a novel biomaterial ink and discussed its critical properties relevant for extrusion-based bioprinting, including viscoelastic properties and printability. The hybrid hydrogel retains the thermogelling properties but is strengthened by the added clay (over 5 kPa of storage modulus and 240 Pa of yield stress). Importantly, the shear-thinning character is further enhanced, which, in combination with very rapid viscosity recovery (~ 1 s) and structure recovery (~ 10 s), is highly beneficial for extrusion-based 3D printing. Accordingly, various 3D patterns could be printed with markedly enhanced resolution and shape fidelity compared to the biomaterial ink without added clay. Graphic abstract
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Marinho, P. V. T., A. S. Macedo, C. R. A. Ferrigno, I. S. Dal-Bó, A. C. B. C. F. Pinto, C. R. G. R. Ontivero, F. Paes et al. „Pediculectomy and fenestration for spinal cord decompression of the lumbar spine of a bush dog (Speothos venaticus) - case report“. Arquivo Brasileiro de Medicina Veterinária e Zootecnia 72, Nr. 4 (August 2020): 1397–402. http://dx.doi.org/10.1590/1678-4162-11586.
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ABSTRACT A captive adult male bush dog (Speothos venaticus) was referred to our Veterinary Medical Teaching Hospital from a local zoo due to a two-week history of progressive hind limb gait impairment and ataxia, non-responsive to clinical management. Computed tomography revealed decreased disc space at L3 - L4 level, with probable disc extrusion narrowing the right side of the spinal canal, compressing the spinal cord. We opted to surgically remove the disc material using both fenestration and right lateral pediculectomy (mini-hemilaminectomy) techniques. Twelve days after surgery there was mild residual proprioceptive ataxia. Gait was fully regained with remission of the neurological deficits around the 30th postoperative day. This is - to the best of our knowledge - the first successful report of a lumbar intervertebral disc extrusion in a bush dog (Speothos venaticus) surgically treated by pediculectomy and disc fenestration.
Dissertationen zum Thema "Responsive extrusion"
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Guerdener, Bruno. „Le dioxyde de carbone comme réactif dans la carbonatation de polymères et copolymères époxydés : du procédé en batch à l'extrusion réactive“. Electronic Thesis or Diss., Saint-Etienne, 2023. http://www.theses.fr/2023STET0055.
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L'objectif de ce projet est de développer des matériaux polymères par extrusion réactive avec des fonctionnalités modulaires en mettant en œuvre une chimie durable basée sur l'utilisation du dioxyde de carbone comme source de carbone.Le cœur de l'étude est d'introduire des fonctions carbonates cycliques à partir du CO2, via des réactions de carbonatation, sur des polymères industriels pour modifier leurs caractéristiques physico-chimiques telles que leur polarité, leur cristallinité, et leur réactivité sans limiter leur recyclabilité. Le défi du projet est d'appliquer de telles modifications chimiques sur les polyoléfines dans une extrudeuse en une seule étape en traitant le système réactif sous haute pression de dioxyde de carbone.Au cours de cette thèse, trois axes de recherche ont pu être explorés. Le premier axe est la carbonatation de polymères industriels contenant des groupes pendants époxydes en utilisant le CO2 comme réactif et des sels d’ammonium comme catalyseurs organiques. La transposition de cette modification en procédé batch vers un procédé d’extrusion réactive a particulièrement été étudiée. Le deuxième axe est la carbonatation oxydante de polyoléfines insaturées en deux étapes en réacteur batch en utilisant des péracides et le CO2 comme réactifs, et des sels d’ammonium comme catalyseurs organiques. Enfin, le troisième axe est la valorisation de ces polymères carbonatés comme intermédiaires pour la synthèse de polyuréthanes sans isocyanate et comme agents compatibilisants pour des mélanges polyéthylène/polycarbonateThe aim of this project is to develop polymer materials harnessing reactive extrusion with modular functionalities by implementing sustainable chemistry based on the use of carbon dioxide as a carbon source.The core of the study is to introduce cyclic carbonate functions from CO2, via carbonatation reactions, on industrial polymers to modify their physico-chemical characteristics such as polarity, crystallinity, and reactivity without limiting their recyclability. The project's challenge is to apply such chemical modifications to polyolefins in a single-step reactive extrusion process by treating the reactive system under high carbon dioxide pressure.During this thesis, three axes of research were explored. The first is the carbonatation of industrial polymers containing epoxy pendant groups using CO2 as reagent and ammonium salts as organocatalysts. The transposition of this modification from a batch process to reactive extrusion was particularly studied. The second axe is the oxidative carbonatation of unsaturated polyolefins in two steps in a batch reactor using peracids and CO2 as reagents, and ammonium salts as organocatalysts. Finally, the last axis is the valorization of these carbonated polymers as intermediates for the synthesis of isocyanate-free polyurethanes and as compatibilizing agents for polyethylene/polycarbonate blends
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Vernaza, Leoro Maria Gabriela. „Desenvolvimento de cereal matinal extrusado organico a base de farinha de milho e farelo de maracuja“. [s.n.], 2007. http://repositorio.unicamp.br/jspui/handle/REPOSIP/256005.
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Orientador: Caroline Joy SteelDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos
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Resumo: É cada vez maior o número de pessoas que procura uma alimentação mais saudável, com alimentos frescos, de boa qualidade biológica e livre de defensivos agrícolas, como são os produtos orgânicos. Percebe-se também que nas dietas contemporâneas em geral existe um "déficit nutricional" de fibras. Este fato tem motivado as autoridades de saúde de diversos países a estimular um maior consumo de fibras por parte da população adulta, seja estimulando o consumo de alimentos como frutas, verduras, leguminosas, raízes, tubérculos e cereais integrais, ou através de produtos comerciais de consumo habitual que tenham sido enriquecidos com fibras. Já existem no mercado ou têm sido estudadas algumas fontes alternativas de fibras, como as fibras de beterraba, de caule de trigo, de laranja, de maracujá e a quitosana. Neste trabalho, optou-se por aproveitar os resíduos da extração de polpa de maracujá como fonte alternativa de fibras. Na extração de polpas e sucos, os resíduos resultantes do processo são normalmente utilizados em ração animal ou como adubo. O objetivo deste trabalho foi estudar o efeito de parâmetros da extrusão termoplástica (umidade da matéria-prima e temperatura de processo) e da adição de fibra sobre propriedades físicas, propriedades físico-químicas e propriedades nutricionais de produtos extrusados, no desenvolvimento de cereal matinal orgânico à base de farinha de milho e farelo de maracujá. A matéria-prima foi caracterizada quanto a sua composição centesimal; teores de fibra alimentar total, solúvel e insolúvel; índices de solubilidade em água (ISA), de absorção de água (IAA), de solubilidade em leite (ISL), de absorção de leite (IAL), de absorção de óleo (IAO), índice glicêmico (IG) e teor de compostos cianogênicos. Após a caracterização da matéria-prima, foi utilizado o processo de extrusão termoplástica para produzir uma base para cereal matinal, otimizando-se a formulação e os parâmetros de extrusão através da Metodologia de Superfície de Resposta, visando a obtenção de um produto com "alto teor de fibras" e propriedades tecnológicas adequadas. Os produtos extrusados foram caracterizados quanto a propriedades físicas, como índice de expansão (IE), cor, dureza e manutenção da textura em leite; propriedades físico-químicas, como ISA, IAA, ISL, IAL e IAO; e propriedades nutricionais, como IG e teor de compostos cianogênicos. Foi observado que o farelo de maracujá utilizado continha alto teor de fibra alimentar total (64,11%), apresentando teores significativos de fibra insolúvel (50,16%) e fibra solúvel (13,95%), ao contrário da farinha de milho que apresentou baixo teor de fibra alimentar total (3,68%), sendo 3,37% fibra insolúvel e 0,31% fibra solúvel. Os valores encontrados na determinação do ISA da farinha de milho e do farelo de maracujá foram 7,14 e 31,66%, respectivamente. O valor do IAA encontrado para a farinha de milho foi de 3,33 g de água/g material seco e para o farelo de maracujá foi de 14,38 g de água/g material seco. Os valores encontrados para o ISL da farinha de milho e do farelo de maracujá foram 5,23 e 14,53%, respectivamente. Os valores do ISL foram menores quando comparados com os valores do ISA. Os valores do IAL encontrados para a farinha de milho e para o farelo de maracujá foram de 3,26 e 12,50 g de leite/g material seco, maiores que os valores de IAA, possivelmente devido à formação de géis de pectina. Os índices de absorção de óleo da farinha de milho e do farelo de maracujá foram de 3,63 e 4,74 g de óleo/g de material seco, respectivamente. Os índices glicêmicos da farinha de milho e do farelo de maracujá foram de 48,03 e 45,00%, respectivamente. O farelo de maracujá apresentou um teor de compostos cianogênicos totais de 748,3 mg/kg. As superfícies de resposta demonstraram que a valores baixos das variáveis estudadas, foi obtida a maior expansão. Já, sobre a dureza dos produtos extrusados, as superfícies demonstraram que o efeito mais importante foi a umidade e a interação dela com a temperatura. Ao aumentar a umidade, a dureza dos produtos extrusados aumentou significativamente. No entanto, foi observado que a temperatura de processo foi o parâmetro que mais influenciou negativamente a textura do produto após 5 minutos de imersão em leite. Em relação à cor dos extrusados, altos níveis de farelo de maracujá diminuíram os valores de L* e hab, produzindo extrusados mais escuros e menos amarelos, ao contrário do efeito da temperatura, onde altas temperaturas aumentaram o valor de L* e o hab, produzindo extrusados mais claros e mais amarelos. Nos produtos extrusados, os maiores valores de ISA foram encontrados para os maiores teores de farelo de maracujá, enquanto que os maiores valores para o IAO foram obtidos com baixos teores de farelo. Aparentemente, não houve efeito das variáveis estudadas sobre o IG dos produtos extrusados. O teor dos compostos cianogênicos foi maior nos produtos com maiores teores de farelo de maracujá, como esperado. Além disso, parace haver um efeito da umidade da matéria-prima na redução dos compostos cianogênicos durante o processo de extrusão. O extrusado considerado como produto ótimo neste trabalho apresentou propriedades adequadas com respeito a IE e dureza. Também apresentou uma porcentagem de fibra alimentar alta (11%), bem superior à exigida pela Legislação Brasileira (6 g/100 g de produto) para ser denominado cereal matinal "com alto teor de fibras"
Abstract: The number of people searching healthier eating habits, including fresh foods of good biological quality and free of pesticides, such as organic products, is increasing. It is also observed that in contemporary diets in general, there is a â?¿nutritional deficitâ?? of fibers. This fact has motivated health authorities of several countries to stimulate a greater ingestion of fibers by the adult population, either by stimulating the consumption of fruits, vegetables, legumes, tubers and wholegrain cereals, or through the enrichment of commonly consumed commercial products. There are already a few alternative fiber sources on the market or under study, such as beetroot, wheat stalk, orange, passion fruit fibers and chitosan. In this work, we opted to use the residues from the extraction of passion fruit pulp as an alternative fiber source. In the extraction of pulps and juices, the residues are usually used as animal feed or fertilizers. The objective of this work was to study the effect of thermoplastic extrusion parameters (raw material moisture content and process temperature) and fiber addition on physical, physical-chemical and nutritional properties of extruded products, as a step in the development of an organic breakfast cereal based on corn flour and passion fruit fiber. The raw material was characterized as to its proximate composition; total, soluble and insoluble fiber contents; water solubility index (WSI), water absorption index (WAI), milk solubility index (MSI), milk absorption index (MAI), oil absorption index (OAI); glycemic index (GI) and cyanogenic compounds. After characterization of the raw material, the thermoplastic extrusion process was used to produce a base for breakfast cereals, optimizing the formulation and process parameters through the Response Surface Methodology, with the aim of obtaining a â?¿high fiber contentâ?? product with adequate technological properties. The extruded products were characterized with respect to physical properties, such as expansion index (EI), color, hardness and maintenance of texture in milk; physicalchemical properties, such as WSI, WAI, MSI, MAI and OAI; and nutritional properties, such as GI and cyanogenic compounds. It was observed that the passion fruit fiber used had a high total fiber content (64.11%), presenting significant contents of insoluble (50.16%) and soluble (13.95%) fibers, different to the corn flour used that presented a low total fiber content (3.68%), of which 3.37% were insoluble fibers and 0.31% soluble fibers. The values found for the WSI of the corn flour and passion fruit fiber were 7.14 and 31.66%, respectively. The values found for the WAI of the corn flour and of the passionfruit fiber were 3.33 and 14.38 g water/g dry material, respectively. The values found for the MSI of the corn flour and passion fruit fiber were 5.23 and 14.53%, respectively. The MSI values were lower than the WSI values. The values found for the MAI of the corn flour and passion fruit fiber were 3.26 and 12.50 g milk/g dry material, higher than those of WAI, possibly due to the formation of pectin gels. The oil absorption indices of the corn flour and passion fruit fiber were 3.63 and 4.74 g oil/g dry material, respectively. The glycemic indices of the corn flour and passion fruit fiber were 48.03 and 45.00%, respectively. The content of cyanogenic compounds in passion fruit fiber were 748,3 mg/kg. The response surfaces demonstrated that at low values of the variables studied, greatest expansion was obtained. For the hardness of the extruded products, the surfaces demonstrated that the most important effect was moisture and its interaction with temperature. Increasing moisture, the hardness of the extruded products increased significantly. However, it was observed that process temperature was the parameter that had the greatest negative effect on the texture of the products after 5 minutes in milk. With respect to color of the extrudates, high levels of passion fruit fiber reduced L* and hab values, producing darker and less yellow extrudates, different to the effect of temperature, where high temperatures increased L* and hab values, producing lighter and more yellow extrudates. In the extruded products, the highest values for WSI were found with the highest passion fruit fiber contents, while the highest values for OAI were obtained with low fiber contents. Apparently, there was no effect of the variables studied on the GI of the extruded products. The content of cyanogenic compounds was higher in the products with greater percentages of passion fruit fiber, as expected. Apart from this, there seems to be an effect of raw material moisture content in the reduction of cyanogenic compounds during the extrusion process. The extrudate considered optimum in this work presented adequate properties with respect to EI and hardness. It also presented a high percentage of dietary fiber (11%), higher than that required by the Brazilian Legislation (6 g/100 g product) to be labeled as a â?¿high fiber contentâ?? breakfast cereal
Mestrado
Mestre em Tecnologia de Alimentos
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Jackson, Adrian. „Homogenisation effects of the hot working of Al-Zn-Mg-Cu alloys“. Thesis, Imperial College London, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.319934.
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Oliveira, Déborah Patrícia Leal. „Snacks, farinha pré-gelatinizada e massa alimentícia elaborados com grãos de milheto [Pennisetum glaucum (L.) R. Br.] e gritz de milho (Zea mays)“. Universidade Federal de Goiás, 2013. http://repositorio.bc.ufg.br/tede/handle/tede/3829.
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Pearl millet is a rich nutritionally cereal, being a major source of protein countries of the semiarid region of the African continent. The pearl millet crops are in expansion on Brazilian Savanna due the plant characteristics that are compatible to the climate and soil of the region. However, in Brazil, the grains of millet are not widely used in food, it was noted with advantageous insertion of this cereal in the diet of the population as this has major advantages over other commonly used cereals as the lowest price, the more quantity and better quality of fiber lipid and protein. The thermoplastic extrusion was used for the preparation of products with the millet that was mixed with corn grits because it presents favorable characteristics for processing used. This study was conducted in order to develop and evaluate the nutritional quality, technological and sensory snacks, pre-gelatinized flour (FPG) and pasta-based mixture of millet [Pennisetum glaucum (L.) R. Br] and gritz of corn (Zea mays L.). For extruding the mixture of grains of millet and corn gritz was used rotational central composite design for the best moisture conditions of the raw material and temperature of the extruder zone 3. The snacks were optimized according to the expandability and pregelatinized flour according to the absorption capacity and water solubility. After optimization of flour, which showed better gelatinization was applied in the preparation of pasta. This was prepared using the mixture design with ternary composition (extruded flour, corn flour and millet raw) to find what proportion of ingredients that got the best features of cooking pasta. Snacks with 11% moisture content of the raw material and 90 ° C temperature were those with greater expansion and were the most desirable second test of desirability. When they were being flavored sensory acceptance and its nutritional composition were classified as high fiber content. The pre-gelatinized flour with highest absorption capacity and water solubility was the one with the same extrusion conditions optimized snack. The proportion of ingredients of the mass had the best cooking conditions was 10% pre-gelatinized flour, 25% corn and 65% of pearl millet flour. The pasta was accepted for flavor, texture and appearance of the panelists. However, it was possible to extrude grains of millet and corn gritz and also the development of products with good nutritional and sensory characteristics.
O milheto é um cereal rico nutricionalmente, sendo uma das principais fontes proteicas em países da região semiárida do continente Africano. No Brasil, mais especificamente no Cerrado, o cultivo deste cereal apresenta-se em expansão devida as características da planta que são compatíveis ao clima e solo da região. No entanto, no Brasil, os grãos de milheto não são muito utilizados na alimentação humana, com isso notou-se vantajoso a inserção deste cereal na alimentação da população já que este apresenta grandes vantagens em relação a outros cereais comumente utilizados, como o preço mais baixo, a maior quantidade de fibras e a melhor qualidade proteica e lipídica. A extrusão termoplástica, uma técnica bastante versátil, foi utilizada para a elaboração de produtos com o milheto que foi misturado ao gritz de milho por este apresentar características favoráveis ao processamento utilizado. Este estudo foi realizado com o objetivo de desenvolver e avaliar a qualidade nutricional, tecnológica e sensorial de snacks, farinha prégelatinizada e massa alimentícia à base de mistura de milheto [Pennisetum glaucum (L.) R. Br.] e gritz de milho (Zea mays). Para a extrusão da mistura de grãos de milheto e gritz de milho foi utilizado o delineamento composto central rotacional para obter as melhores condições de umidade da matériaprima e temperatura da 3ª zona do extrusor. Os snacks foram otimizados conforme a capacidade de expansão e a farinha pré-gelatinizada de acordo com a capacidade de absorção e solubilidade em água, ou seja, gelatinizada. A farinha pré-gelatinizada otimizada foi aplicada na elaboração de massa alimentícia. Esta foi elaborada utilizando o delineamento de misturas com composição ternária (farinha extrusada, fubá de milho e farinha de milheto crua) para encontrar qual a proporção de ingredientes que obtivesse as melhores características de cozimento da massa. Os snacks e a massa alimentícia foram analisados microbiologicamente para a realização da análise sensorial. Os snacks com 11% de umidade da matéria-prima e 90 °C de temperatura foram os que apresentaram maior expansão e foram os mais desejáveis segundo teste de desejabilidade. Ao serem aromatizados eles foram aceitos sensorialmente e em sua composição nutricional foram classificados como alto teor de fibras. A farinha pré-gelatinizada que obteve maior capacidade de absorção e solubilidade em água também foi o experimento com 11% de umidade e 90 °C de temperatura. A proporção de ingredientes da massa que teve as melhores condições de cozimento foi a de 10% farinha pré-gelatinizada, 25% de fubá de milho e 65% de farinha de milheto. A massa alimentícia foi aceita em relação ao sabor, textura e aparência entre os provadores. Contudo, foi possível a extrusão de grãos inteiros de milheto e gritz de milho e ainda a elaboração de produtos com boas características nutricionais, tecnológicas, microbiológicas e sensoriais segundo atributos sabor, aparência e textura.
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Ferreira, Reinaldo Eduardo. „Avaliação de parametros do processo de extrusão e do teor de farelo de trigo adicionado em caracteristicas de "snacks" expandidos de milho“. [s.n.], 2006. http://repositorio.unicamp.br/jspui/handle/REPOSIP/256004.
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Orientador: Caroline Joy SteelDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos
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Mestrado
Mestre em Tecnologia de Alimentos
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Bombo, Aurea Juliana. „Obtenção e caracterização nutricional de snacks de milho (Zea mays L.) e linhaça (Linum usitatissimum L.)“. Universidade de São Paulo, 2006. http://www.teses.usp.br/teses/disponiveis/6/6133/tde-23102006-115234/.
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O processo de cozimento por extrusão é uma técnica de grande importância para a indústria de alimentos, empregada na produção de snacks, cereais matinais, proteínas texturizadas, etc. Os snacks ou salgadinhos com base de milho são designados como alimentos desprovidos de valor nutricional, mas constituem-se hábito de consumo da população, sendo assim, melhorar a qualidade de tais produtos é uma importante medida de Saúde Pública. O presente trabalho teve por objetivo desenvolver um processo para obter um snack de milho com adição de linhaça e maior valor nutricional que tenha potencial para intervenções nutricionais em grupo populacional específico ou para consumo geral. A partir de ensaios prévios foram delineados dois planejamentos compostos centrais (D1 e D2), com 3 variáveis independentes: umidade (U), temperatura do equipamento (T) e adição de linhaça (L). As variáveis-resposta foram razão de expansão (RE) e força para cisalhamento (FC) por estarem diretamente correlacionadas com a aceitabilidade do produto. A regressão para o modelo quadrático do D1 apresentou R2 (%) de 89 (RE) e 84,4 (FC), mas houve falta de ajuste do modelo (p<0,05). Já para o D2 o R2 foi 84 (RE) e 70 (FC), o modelo não apresentou falta de ajuste e a regressão foi significativa (p<0,05) somente para RE. Foram significativos os efeitos lineares U e T, quadrático U e interação UT, independendo de L. Calculando-se as derivadas do modelo preditivo foi encontrado ponto ótimo que reproduziu a expansão máxima. O snack ótimo (30% L) apresentou composição (base seca): 14,7% proteína, 0,2% lipídeos, 1,7% cinzas, 4,9% fibras solúveis e 10,3% fibras insolúveis. Na análise sensorial o atributo cor foi rejeitado e sabor, textura e aparência geral foram aceitos. Comparado aos snacks de milho convencionais, que contém menos de 2% de fibras, a adição de linhaça permitiu o uso do atributo alto teor de fibras, segundo a legislação brasileira, além da maior quantidade protéica obtida. O presente trabalho está submetido à patente intitulada: Farinha para fabricação de gêneros alimentícios, solução aromatizante livre de gordura vegetal hidrogenada para fabricação de gêneros alimentícios, biscoito tipo "snack" light e de elevado valor nutritivo, e processo para a fabricação do mesmo. 2005. Patente: Privilégio de Inovação no 0502694-6.Extrusion cooking is a very important process for the food industry, used to manufacture a series of products as expanded snack foods, breakfast cereals, texturized proteins, etc. Corn snacks are nick-named as junked foods or are being considered foods with calories and no nutrients. Nevertheless they are largely consumed by the population, and this consumption has grown considerably in the past years, because of that, to improve nutritional value of those products will have a significative impact in population health. The aim of this work was to develop a process to obtain a corn based snack added of flaxseed with high nutritive quality that could be useful in nutritional programs. After initial experiments, 2 central composite designs (D1 and D2) were modeled, with 3 independent variables: moisture, temperature and flaxseed addition. The dependent (response) variables were: expansion ratio (ER) and shear strength (SS) because they are highly correlated with acceptability. The regression analysis for the quadratic model showed: D1: R2 = 89% (ER) and 84% (SS), but the model showed lack of fit; D2: R2 = 84% (ER) and 70% (SS), the model didnt show lack of fit and the regression was statistically significant only for ER (p< 0.05). The results indicated that linear effects of both moisture and temperature, second order effect of temperature and interaction between moisture and temperature were significant. Flaxseed addition wasnt significant. The derivatives of ER indicated an optimum point that reproduced maximum expansion. The optimum snack (30% flaxseed) has the composition (d.s.b.): 14.7% protein, 0.2% lipids, 1.7% ash, 4.9% soluble fiber and 10.3% insoluble fiber. The sensorial analysis revealed that color was rejected and flavor, texture and general aspect were accepted. Comparing to the traditional corn snacks that have less than 2% of fiber, the corn based flax snack besides the increment in protein can be named high content of fiber according to the Brazilian legislation.
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Licata, Rebecca Lynn. „Using response surface methodology to model the impact of extrusion on starch digestibility and expansion of sorghum maize composite flour“. Thesis, Curtin University, 2012. http://hdl.handle.net/20.500.11937/2500.
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Sorghum is a major drought and high temperature tolerant grain crop currently used mainly as animal feed in Australia. This study investigated high temperature high pressure extrusion cooking for the manufacture of snack-food like products using sorghum. Response surface methodology statistical modelling was successfully used to specify the optimal formulation and processing conditions to manufacture an expanded product with high levels of slowly digestible starch with potential for assisting in healthy blood glucose control.
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Désire, Amélie. „Extrusion-sphéronisation de produits pharmaceutiques : comparaison et transposition à échelle industrielle de procédés d’extrusion par plans d’expériences“. Thesis, Paris 11, 2011. http://www.theses.fr/2011PA114816/document.
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Parmi les différents procédés d’élaboration de minigranules, le procédé d’extrusion-sphéronisation présente de nombreux avantages, puisqu’il permet notamment d’élaborer des minigranules fortement chargées en principe actif et d’éviter l’emploi de solvants organiques. Ce travail a pour objectif de comparer les performances de plusieurs systèmes d’extrusion à vis, de l’échelle du laboratoire jusqu’à la transposition à l’échelle industrielle. Pour cela, des plans d’expériences ont été construits afin d’identifier les variables critiques et de sélectionner l’extrudeur le plus favorable selon différentes approches spécifiques à cette étude. En effet, le système d’extrusion idéal est défini dans ce travail comme celui donnant les meilleurs résultats en termes de productivité et de caractéristiques des minigranules (« qualité »), entraînant le moins d’impact sur le produit après transposition d’échelle (« transposabilité »), montrant le moins d’influence sur le produit lorsque la formule utilisée change (« robustesse »), et permettant d’ajuster ou d’améliorer la qualité des minigranules lorsque les conditions opératoires varient (« flexibilité »). Quelle que soit l’approche étudiée, les résultats ont permis de mettre en évidence l’influence de paramètres critiques et de leurs interactions sur les différentes réponses et ont montré des différences entre les différents systèmes d’extrusion. L’étude à l’échelle du laboratoire a permis de comparer les extrudeurs radial, dôme et frontal et a mis en évidence l’intérêt des systèmes frontal et dôme en termes de qualité des minigranules, et du système radial en termes de robustesse et de flexibilité du procédé. L’étude à l’échelle industrielle a permis de comparer les extrudeurs radial et frontal, et a permis d’identifier l’extrudeur frontal comme étant le plus favorable en termes de qualité des minigranules, de robustesse, de flexibilité et de transposabilité. Les conclusions observées à l’échelle industrielle sont donc différentes de celles considérées à l’échelle du laboratoire, pour l’étude comparative des différents systèmes. Cela confirme l’importance de tester les systèmes à échelle industrielle avant l’acquisition d’un équipementAmong the various methods of developing minigranules, extrusion-spheronization has many advantages, particularly since it allows to develop minigranules highly charged with active pharmaceutical ingredient and to avoid the use of organic solvents. This work aims to compare the performance of several extrusion screws systems, from the lab to the scale-up at industrial scale. Designs of experiments were built to identify critical variables and compare the extruder in terms of different approaches specific to this study. As a matter of fact, the ideal extrusion system is defined in this work as the one which gives the best results in terms of productivity and pellets characteristics (“quality”), the one which shows less impact on the product after scaling-up (“scalability”), the one which shows the less influence on these same properties when the formula used changes (“robustness”), and the one which allows the possibility to adjust or improve pellets properties with operating variables (“flexibility”). Whatever the approach studied, the results allowed to highlight the influence of critical parameters and their interactions on the different responses and showed differences between the different extrusion systems. The study at lab scale compared radial, dome and axial extruders and underlined the interest of axial and dome systems in terms of pellets quality, and radial system in terms of process robustness and flexibility. The study at industrial scale compared radial and axial systems, and identified the axial system as the most favorable in terms of pellets quality , robustness, flexibility and scalability. The conclusions observed at industrial scale are different from those observed at lab scale for the different systems comparative study. This confirms the importance to test systems at industrial scale before investing in one equipment
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Olivieri, Camila Mattos Rocha. „Efeito das farinhas de jatobá-do-cerrado (Hymenaea stigonocarpa Mart.) in natura e extrusada no metabolismo lipídico e parâmetros fermentativos em hamsters e resposta glicêmica em humanos após a extrusão“. Universidade de São Paulo, 2016. http://www.teses.usp.br/teses/disponiveis/6/6138/tde-06052016-141240/.
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Introdução: A polpa farinácea do jatobá-do-cerrado (Hymenaea stigonocarpa Mart.) apresenta alto teor de fibra alimentar, em média 60 g/100 g, que são importantes para a redução do risco e controle de doenças crônicas não transmissíveis (DCNT). A extrusão termoplástica neutraliza aromas intensos, proporciona a formação de amido resistente, aumenta a fibra alimentar solúvel e melhora a textura do produto final. Objetivo: Estudar o efeito das farinhas de jatobá-do-cerrado in natura (FIN) e extrusada (FE) no metabolismo lipídico e parâmetros fermentativos em hamsters, bem como verificar a resposta glicêmica em humanos após a extrusão. Métodos: Processo de extrusão: velocidade de 200 rpm; matriz com 4 mm de diâmetro; taxa de compressão 3:1; alimentação constante de 70 gramas/minuto; temperatura de 150 °C; proporção farinha de jatobá-do-cerrado e amido de milho: 70:30 por cento e umidade a 25 por cento . Foi realizado um experimento animal com hamsters durante 21 dias, em que se analisou alguns parâmetros do metabolismo lipídico e colônico (fermentativos) dos animais, divididos em quatro grupos experimentais, se diferenciando pela dieta. As dietas controle (GC), in natura (GFI) e extrusada (GFE) eram hipercolesterolemizantes (13,5 por cento de gordura de coco e 0,1 por cento de colesterol) e a dieta referência (GR) com óleo de soja como fonte lipídica, não. Todas as dietas apresentavam 15 por cento de fibra alimentar, sendo que as dietas GR e GC tinham como fonte de fibra a celulose, e as dietas GFI e GFE tiveram as próprias fibras como fonte. A resposta glicêmica em humanos foi verificada por meio do ensaio do índice glicêmico e carga glicêmica da FE, com dez voluntários saudáveis que consumiram 25 gramas de carboidratos disponíveis do alimento teste (farinha extrusada) ou do pão branco como alimento controle. Resultados: Não foi observada diferença significativa entre o peso final, ingestão diária média e total, ganho de peso e CEA entre os animais dos quatro grupos. A concentração de triglicerídeos foi menor em 41 por cento e 38 por cento nos animais que receberam as dietas GFI e GFE, em relação aqueles que receberam a dieta GC, assim como também para o colesterol total (55 por cento e 47 por cento ), LDL-c (70 por cento e 53 por cento ) e não-HDL-c (63 por cento e 49 por cento ) séricos, lipídeos totais hepáticos (39 por cento e 45 por cento ) e o peso dos fígados dos animais também foi menor (21 por cento em ambos os grupos). Não houve diferença no colesterol hepático e excretado nas fezes dos animais dos quatro grupos. Os animais do GFE excretaram 57 por cento mais ácidos biliares nas fezes que os animais do GC. Com relação aos parâmetros fermentativos, observou-se maior excreção de fibras (1,24 ± 0,08 e 1,52 ± 0,09 gramas) nos animais dos grupos GR e GC respectivamente, em relação aos do GFI e GFE (0,50 e 0,48 gramas), porém o escore fecal (3,50 ± 0,19 e 3,38 ± 0,18) e o grau de fermentação (54 e 52 por cento ) foi maior nos animais dos grupos GFI e GFE. Houve uma maior produção de AGCC no ceco dos animais dos grupos GFI e GFE (80 e 57,5 µmol/g de ceco respectivamente) e maior diminuição do pH no conteúdo cecal nos animais do grupo GFI (7,49 ± 0,10), em relação ao GC (8,06 ± 0,13). Os ácidos acético e propiônico, estiveram presentes em maior quantidade no ceco dos animais dos grupos GFI (58,5 e 6,1 µmol/g de ceco) e GFE (42,5 e 6,6 µmol/g de ceco) e os animais do GFI produziram mais ácido butírico (15 µmol/g de ceco), em relação aos demais grupos. Quanto à resposta glicêmica da farinha pós extrusão, não houve diferença entre a área de resposta glicêmica da farinha extrusada e do pão branco, o índice glicêmico da farinha extrusada (glicose como controle) foi classificado como moderado, e a carga glicêmica (na porção de 30 gramas), baixa. Conclusão: As FIN e FE favoreceram a redução do colesterol total, LDL-c, não-HDL-c e dos triglicerídeos séricos, além da diminuição do acúmulo de lipídeos hepáticos. Foi observado também aumento expressivo na formação de AGCC e no grau de fermentação. A FE proporcionou um aumento na excreção de ácidos biliares nas fezes e apresentou índice glicêmico moderado e baixa carga glicêmica.Introduction: The mealy pulp of jatobá-do-cerrado (Hymenaea stigonocarpa Mart.) has high dietary fiber content, on average 60 g/100 g, which is important for reducing risk and control chronic non-communicable diseases (NCDs). The thermoplastic extrusion neutralizes intense flavors, formation of resistant starch, increases soluble dietary fiber and improves the texture of the final product. Objectives: Check the effect of jatobá-do-cerrado flour in natura (IF) and extruded (EF) on lipid metabolism and fermentation parameters in hamsters as well as the glycemic response in humans after extrusion. Methods: Extrusion cooking: speed of 200 rpm; 4 mm die diameter; compression ratio 3:1; constant feed rate 70 g/min; temperature 150 °C; ratio of jatobá-do-cerrado flour to corn starch: 70:30 per cent and 25 per cent moisture. A 21-day biological experiment with hamsters was conducted, in which parameters of the animals lipid metabolism and colonic (fermentation) were analyzed; they were divided into four groups, differing by diet. The control diets (CG), in natura (IFG) and extruded (EFG) were hypercholesterolemic (13.5 per cent coconut fat and 0.1 per cent cholesterol), and the reference diet (RG) with soybean oil as a lipid source was not. All diets had 15 per cent of dietary fiber, being that RG and CG diets had the cellulose fiber source, and IFG and EFG diets had the fibers themselves as a source. The glycemic response in humans was evaluated by the glycemic index and glycemic load test of EF, with ten healthy volunteers who consumed 25 grams of available carbohydrate food test (extruded) or white bread as food control. Results: There was no significant difference between final weight, average total and daily intake, weight gain and FER between animals of the four groups. The values of triglycerides were lower by 41 per cent and 38 per cent in the animals receiving the IFG and EFG diets, for those who received the CG diet, as well as for total cholesterol (55 per cent and 47 per cent ), LDL-c (70 per cent and 53 per cent ) and non-HDL-c levels (63 per cent and 49 per cent ) serum, liver lipids (39 per cent and 45 per cent ) and the animals\' livers weight was lower (21 per cent in both groups). There was no difference in hepatic cholesterol and excreted in feces of animals of the four groups. The animals of the EFG group excrete 57 per cent more bile acids in stool than animals CG. Regarding the fermentation parameters, we observed increased excretion of fibers (1.24 ± 0.08 and 1.52 ± 0.09 g) in animals of RG and CG respectively, in relation to IFG and EFG (0.50 and 0.48 grams), but the fecal score (3.50 ± 0.19 and 3.38 ± 0.18) and the degree of fermentation (54 and 52 per cent ) were higher in animal IFG and EFG groups. There was a greater production of SCFA in the caecum of animals IFG groups and EFG (80 to 57.5 µmol/g caecum respectively) and greater decrease in pH in the cecal contents of IFG animals group (7.49 ± 0.10) compared to the control group (8.06 ± 0.13). The acetic and propionic acids were present in higher amounts in the caecum of animals IFG groups (58.5 and 6.1 µmol/g caecum) and EFG (42.5 and 6.6 µmol/g caecum) and the animals of IFG group produced more butyric acid (15 µmol/g caecum), compared to other groups. Concerning the glycemic response of flour after extrusion, there was no difference between the glycemic response area of extruded flour and white bread, the glycemic index of extruded flour (glucose as a control) was classified as moderate and glycemic load (the portion of 30 grams) low. Conclusion: IF and EF aided in the reduction of total cholesterol, LDL-c, non-HDL-c and triglycerides, as well as decreased the accumulation of liver lipids. A significant increase in the SCFA and degree of fermentation was also observed. The EF increased the excretion of bile acids in stool, and presented moderate glycemic index and low glycemic load.
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Simon, Anish Abraham. „Shape memory response and microstructural evolution of a severe plastically deformed high temperature shape memory alloy (NiTiHf)“. Thesis, Texas A&M University, 2004. http://hdl.handle.net/1969.1/3139.
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NiTiHf alloys have attracted considerable attention as potential high temperature Shape Memory Alloy (SMA) but the instability in transformation temperatures and significant irrecoverable strain during thermal cycling under constant stress remains a major concern. The main reason for irrecoverable strain and change in transformation temperatures as a function of thermal cycling can be attributed to dislocation formation due to relatively large volume change during transformation from austenite to martensite. The formation of dislocations decreases the elastic stored energy, and during back transformation a reduced amount of strain is recovered. All these observations can be attributed to relatively soft lattice that cannot accommodate volume change by other means. We have used Equal Channel Angular Extrusion (ECAE), hot rolling and marforming to strengthen the 49.8Ni-42.2Ti-8Hf (in at. %) material and to introduce desired texture to overcome these problems in NiTiHf alloys. ECAE offers the advantage of preserving billet cross-section and the application of various routes, which give us the possibility to introduce various texture components and grain morphologies. ECAE was performed using a die of 90º tool angle and was performed at high temperatures from 500ºC up to 650ºC. All extrusions went well at these temperatures. Minor surface cracks were observed only in the material extruded at 500 °C, possibly due to the non-isothermal nature of the extrusion. It is believed that these surface cracks can be eliminated during isothermal extrusion at this temperature. This result of improved formability of NiTiHf alloy using ECAE is significant because an earlier review of the formability of NiTiHf using 50% rolling reduction concluded that the minimum temperature for rolling NiTi12%Hf alloy without cracks is 700°C. The strain level imposed during one 90° ECAE pass is equivalent to 69% rolling reduction. Subsequent to ECAE processing, a reduction in irrecoverable strain from 0.6% to 0.21% and an increase in transformation strain from 1.25% to 2.18% were observed at a load of 100 MPa as compared to the homogenized material. The present results show that the ECAE process permits the strengthening of the material by work hardening, grain size reduction, homogeneous distribution of fine precipitates, and the introduction of texture in the material. These four factors contribute in the increase of stability of the material. In this thesis I will be discussing the improvement of mechanical behavior and stability of the material achieved after various passes of ECAE.
Bücher zum Thema "Responsive extrusion"
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Vainionpaa, Jukka. Modelling and analysis of the extrusion cooking of cereals and cereal-based mixtures using response surface methodology. 1994.
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Lin, Michael, und Erin S. Williams. Open Globe Repair. Herausgegeben von Erin S. Williams, Olutoyin A. Olutoye, Catherine P. Seipel und Titilopemi A. O. Aina. Oxford University Press, 2018. http://dx.doi.org/10.1093/med/9780190678333.003.0030.
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Penetrating eye injury in the pediatric patient is an emergency that requires careful management by the anesthesiologist to prevent further eye damage by the potential extrusion of vitreous fluid. Additionally, since these injuries are due to trauma, the patients typically are not adequately fasted for surgery. Thus prevention of aspiration of gastric contents must also be considered during the perioperative management of the child with an open globe injury. Depending on the risk of aspiration, the anesthesiologist must determine whether to use succinylcholine, a nondepoloarizing muscle relaxant, or no muscle relaxant at all, prior to laryngoscopy. A delicate balance must exist to achieve a smooth induction of anesthesia, blunted response to airway stimulation during laryngoscopy and intubation, and prevention of aspiration. During the perioperative period, the pediatric anesthesiologist can employ a variety of methods to limit the potential for increased intraocular pressure in the patient with penetrating eye trauma.
Buchteile zum Thema "Responsive extrusion"
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Trujillo, Carl P., Eric N. Brown und G. T. Gray. „Dynamic-tensile-extrusion response of polytetrafluoroethylene (PTFE) and polychlorotrifluoroethylene (PCTFE)“. In Dynamic Behavior of Materials, Volume 1, 73–75. New York, NY: Springer New York, 2011. http://dx.doi.org/10.1007/978-1-4419-8228-5_11.
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Martinez, Daniel T., Carl P. Trujillo, Ellen K. Cerreta, Joel D. Montalvo, Juan P. Escobedo-Diaz, Victoria Webster und G. T. Gray. „Influence of Texture and Temperature on the Dynamictensile-Extrusion Response of High-Purity Zirconium“. In Dynamic Behavior of Materials, Volume 1, 297–305. New York, NY: Springer New York, 2011. http://dx.doi.org/10.1007/978-1-4614-0216-9_42.
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Poole, W. J., Y. Wang, A. Zang, M. A. Wells und N. C. Parson. „The Influence of Crystallographic Texture Gradients on the Deformation Response of Aluminum Extrusions“. In The Minerals, Metals & Materials Series, 258–61. Cham: Springer Nature Switzerland, 2023. http://dx.doi.org/10.1007/978-3-031-22532-1_35.
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Zhang, Jie, Junlin Chen, Dan Yao, Jiang Li und Shaoyun Guo. „Numerical Investigation on the Low-Frequency Vibroacoustic Response of an Aluminium Extrusion Compounded with Acoustic Metamaterials“. In Lecture Notes in Mechanical Engineering, 563–72. Singapore: Springer Nature Singapore, 2024. http://dx.doi.org/10.1007/978-981-99-7852-6_53.
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Beura, V., A. Sharma, S. Sharma, V. Joshi und K. N. Solanki. „Investigating the Corrosion Response of Cast and Extruded ZK60 Magnesium Alloy Processed via Shear Assisted Processing and Extrusion“. In Magnesium Technology 2024, 31–33. Cham: Springer Nature Switzerland, 2024. http://dx.doi.org/10.1007/978-3-031-50240-8_6.
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Worku Kidane, Solomon. „Application of Response Surface Methodology in Food Process Modeling and Optimization“. In Response Surface Methodology in Engineering Science. IntechOpen, 2021. http://dx.doi.org/10.5772/intechopen.100113.
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Modeling and optimization is an important task in food manufacturing. It enables one to understand and describe processes which in turn help establish quantified relationship between input and output variables. Modeling and optimization help to make informed decision on a process with the objective of improving efficiency and minimizing cost while maintaining quality. Response surface Methodology (RSM) has been employed in modeling and optimizing several food processing operations including baking, cooking, roasting, drying, extrusion, fermentation and many others. Moreover, RSM has been extensively used in product formulation and ingredient optimization. This chapter describes the application of RSM in food process modeling and optimization. The steps to be followed, the experimental designs that can be used and the interpretation of response surfaces developed are described. Moreover, selected application of RSM in food process modeling and optimization are reviewed and presented.
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Ortiz-Romero, Nallely, Efren Delgado, Gerardo Antonio Pámanes-Carrasco, Hiram Medrano-Roldán, Vicente Hernández-Vargas und Damián Reyes-Jáquez. „Development and Evaluation of an Extruded Balanced Food for Sheep Based on Cottonseed Meal (Gossypium hirsutum)“. In Cotton [Working Title]. IntechOpen, 2022. http://dx.doi.org/10.5772/intechopen.102425.
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The objective of this research was to evaluate the effect of the content of cottonseed meal (Gossypium hirsutum) and the processing variables on the functional properties and the content of gossypol of an extruded feed for sheep (Ovis aries). The diet was balanced according to the requirements of fattening Dorper sheep breed under 1 year. The extrusion process was optimized using a surface response methodology, with four independent variables: temperature in the last heating zone (120–160°C), moisture content (14–18%), screw speed (120 rpm–180 rpm), and cottonseed meal content (9 g–27 g 100 g−1), in a single screw extruder. The optimal food had 27.25% crude protein, 4.24% crude fat, 12.21% crude fiber, 46.95% nitrogen-free extract, and 9.35% ash. The composition of essential amino acids in the optimal diet was 1.00 g kg−1 of lysine, 1.25 g kg−1 of phenylalanine, 2.04 g kg−1 of leucine, 0.87 g kg−1 of isoleucine, 0.98 g kg−1 of threonine, 1.15 g kg−1 of valine, and 0.65 g kg−1 of histidine. The fatty acids present in the highest concentration in the optimal diet were 2.14% linoleic acid, 1.11% oleic acid, and 0.81% palmitic acid. The gossypol content of the optimal diet was less than 0.1%, which ensures the safety of cottonseed meal as a protein source. The optimum conditions of the extrusion process were 120°C temperature, 120 rpm screw speed, 14.00% humidity, and 27 g 100 g−1 cottonseed meal.
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Yunoki, Shunji, Eiji Kondo und Kazunori Yasuda. „Mechanical Methods of Producing Biomaterials with Aligned Collagen Fibrils“. In Collagen Biomaterial [Working Title]. IntechOpen, 2022. http://dx.doi.org/10.5772/intechopen.104734.
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Collagen has been used in various therapeutic medical devices, such as artificial dermis, bone, and cartilage, wherein the effectiveness of collagen mainly depends on its biological features of biocompatibility, biodegradability, bioresorbability, cell affinity, and weak antigenicity. Collagen is the main structural protein in the human body and is responsible for the mechanical properties of tissues and organs. The fundamental structural component of tendon tissue is uniaxially aligned collagen fibrils that run parallel to the geometrical axis. Thus, the fabrication of artificial tendons is an excellent example of developing biomaterials using collagen as a structural backbone. Previous attempts to construct aligned fibril-based biomaterials involved electrospinning, freeze drying, using a strong magnetic field, and mechanical methods, including shearing and tension during wet extrusion. Among these, mechanical methods have been extensively studied owing to their simplicity and effectiveness suitable for mass production. However, few review articles have focused on these mechanical methods. Thus, this article reviews the mechanical methods for creating biomaterials from aligned collagen fibril while discussing the other fabrication methods in brief.
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Rasi-Caldogno, F., und M. I. De Michelis. „The plasma-membrane Ca2+ pump: biochemical characteristics and regulatory properties“. In Biochemical Mechanisms Involved in Plant Growth Regulation, 259–71. Oxford University PressOxford, 1994. http://dx.doi.org/10.1093/oso/9780198577645.003.0020.
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Abstract An increasing amount of evidence indicates that Ca2+ can act as a second messenger in the transduction of internal and environmental stimuli in higher plants (Poovaiah and Reddy 1987). The suitability of Ca2+ as a second messenger is suggested by its very low (about 0.1 µM) concentration in the cytosol under resting conditions, and by the immediate increase of its concentration in response to different stimuli (Felle 1988; Johannes et al. 1991; Schroeder and Thuleau 1991). Because of the enormous electrochemical gradient of Ca2+ existing between the cytosol and the apoplast or intracellular compartments, the rapid increase of cytosolic Ca2+ concentration induced by stimuli can be brought about by the opening of Ca2+ channels of the plasma membrane and/or of endomembranes (Tester 1990; Schroeder and Thuleau 1991). Re-establishment and maintenance of the resting level of cytosolic Ca2+ depends on the activity of active transport systems that catalyse Ca2+ extrusion from the cytoplasm to the apoplast or to intracellular compartments such as the vacuole, endoplasmic reticulum, mitochondria, and chloroplasts.
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Dudeja, Isha, Muskan Gupta, Ramandeep Kaur Mankoo und Arashdeep Singh. „Pigmented Maize: Nutritional Properties and Bioactive Profile“. In Pigmented Cereals and Millets, 50–82. The Royal Society of Chemistry, 2023. http://dx.doi.org/10.1039/9781837670291-00050.
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Maize (Zea mays L.) is the queen of cereals and is the third largest produced and consumed grain in the world, after rice and wheat. Scientific studies have concentrated on pigmented maize in recent decades, and breeding procedures have been identified to raise the anthocyanin content in unpigmented types using alternative strategies. Pigmented (pink, red, purple, blue, and black) maize has attracted much attention for its health-beneficial properties, mainly due to bioactive compounds such as anthocyanins, and its carotenoid composition, which are also responsible for its pigmentation. The pigmentation of maize is also attributed to the prevalence of many secondary metabolites such as polyphenolics, carotenoids, and flavonoids. Maize cells have a wide variety of pigments, ranging from yellow-orange to dark purple-blue, as well as white and creamy pigments, caused by the different expressions of these pigments. Pigments are located in the dense pericarp or aleurone regions of the kernels. Processing of pigmented maize such as nixtamalization, cooking, baking, germination, extrusion, etc. to prepare various foods significantly modulated its bioactive compounds, anthocyanin content, and antioxidant activities. The utilization of pigmented maize in different products not only enhances their nutritional and bioactive potential, but also helps to regulate starch digestibility by increasing the contents of slowly digestible starch and resistant starch, thus lowering the glycemic index of the products.
Konferenzberichte zum Thema "Responsive extrusion"
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Pizzutti, Alice Elisa, und Luíza Fruett M. de Lima. „Clinical case of intervertebral disc disease (IVDD)“. In III SEVEN INTERNATIONAL MULTIDISCIPLINARY CONGRESS. Seven Congress, 2023. http://dx.doi.org/10.56238/seveniiimulti2023-078.
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IVDD is an intervertebral disc injury characterized by extrusion of the disc into the spinal canal, compressing the spinal cord and causing limb paralysis. Diagnosis involves anamnesis, clinical history, physical and neurological examination. Treatment is clinical or surgical, depending on the degree, extent and location. The present report aims to describe the clinical therapeutic evolution of low-grade thoracolumbar IVDD. A male dachshund, 4 years old, 7 kg, with walking difficulties was seen at the UPF Veterinary Hospital. He manifested ambulatory paraparesis and decreased proprioception in both pelvic limbs. Radiographic examination showed calcification of intervertebral disc T5-L1, and decreased intervertebral space T9-T10. We decided to perform clinical treatment by hospitalizing the patient to maintain absolute rest with intravenous prescription of fluid therapy, analgesics (dipyrone and methadone), and anti-inflammatory (methylprednisolone). Bladder catheterization was performed to monitor urine output. The dog was responsive to treatment, having good sensory and motor response in both pelvic limbs and after 5 days hospitalized continued to be willing, so the probe was removed and he was able to urinate in bed without algia to adopt the position. Small walks were made on grass and non-slip floor with support, in which proprioceptive return of the limbs was noted. The patient was then discharged. Oral gabapentin was prescribed for 30 days, prednisone and omeprazole for 7 days. The patient remained clinically well, performed acupuncture and physiotherapy sessions for one month and after this period continued to perform sporadic physiotherapy and his condition remained stable. The clinical therapeutic treatment was effective, along with integrative therapies that helped in muscle strengthening and pain control of the patient.
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de Nardo, Luigi, Sabrina De Cicco, Matteo Jovenitti, Maria C. Tanzi und Silvia Fare`. „Shape Memory Polymer Porous Structures for Mini-Invasive Surgical Procedures“. In ASME 8th Biennial Conference on Engineering Systems Design and Analysis. ASMEDC, 2006. http://dx.doi.org/10.1115/esda2006-95559.
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In the recent past, clinical procedures underwent huge modifications. Among them, mini-invasive surgery has modified the clinical practice and the quality of life of patients. All these evolutions are strictly correlated to the advancement in materials science. Shape Memory Polymers (SMPs), a novel class of stimuli-responsive materials, can be considered ideal candidates for the design of devices for mini-invasive surgery. Such devices can be inserted in a compact temporary shape and subsequently expanded at body temperature: a bone defect, e.g., could be filled by a filler made of SMPs. With the aim of promoting tissue integration and healing, these structures should present a suitable porosity. In this work two different processing techniques to obtain shape memory polymer scaffolds from Calo·MER™, a SMP, are presented. Porous structures were obtained by micro-extrusion, with different chemical expanding agents or by particulate leaching with salt. Morphology, thermo-mechanical and shape recovery properties of the SMP porous samples were investigated. The obtained foams show a well interconnected morphology, with a pore size in the range suitable for bone applications. Shape memory properties were not significantly affected by the transformation processes: a good ability of recovering the original shape was verified. Therefore, foams obtained from these materials could be used to fabricate devices for mini-invasive surgical procedures.
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Ghosh, Avishek. „3D Printing of Designed Ultra-Low Loss Microwave Dielectrics for Beyond 5G Applications“. In ASME 2022 17th International Manufacturing Science and Engineering Conference. American Society of Mechanical Engineers, 2022. http://dx.doi.org/10.1115/msec2022-85805.
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Abstract Low-temperature sintering ceramics with high dielectric permittivity and low loss are highly valuable to the communication industry. Additive Manufacturing (AM) exhibits excellent potential to process a wide range of engineering materials and deliver complex three-dimensional structures in various scales, with several benefits over traditional manufacturing methods used in electronics manufacturing. Therefore, the advent of AM has offered a radically new way of designing and manufacturing electronic and communication components with tailored performance. In this work, a stable ink has been formulated from ultra-low loss dielectric bismuth molybdate (Bi2Mo2O9) ceramics. The formulated ink exhibited suitable rheological properties responsive to the direct ink writing technique. The 3D printed components with good structural integrity and spatial resolution were sintered at 670°C for 4 hours using the conventional heating method, achieving > 94% density. A series of components with varying shapes and designed porosities were fabricated using the extrusion 3D printing method. The relative permittivity (εr) and loss tangent (tanδ) for the 3D printed and sintered Bi2Mo2O9 solid components were found to be 36.5 and 0.0005, respectively, at ∼8GHz, and the values can be tailored using designed porosity. The dielectric performance was found to be excellent and stable even at very high-frequency regimes (beyond 5G) between 70–90 GHz. Further, the addition of metallic infills in the designed pores of the ceramic scaffolds resulted in an increase in permittivity values. The preliminary investigation exhibited the potential to fabricate ceramic components for high-frequency applications via the design freedom offered by AM, that can enable further miniaturization of future communication devices.
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Brown, E. N., C. P. Trujillo, G. T. Gray, Mark Elert, Michael D. Furnish, William W. Anderson, William G. Proud und William T. Butler. „DYNAMIC-TENSILE-EXTRUSION RESPONSE OF FLUOROPOLYMERS“. In SHOCK COMPRESSION OF CONDENSED MATTER 2009: Proceedings of the American Physical Society Topical Group on Shock Compression of Condensed Matter. AIP, 2009. http://dx.doi.org/10.1063/1.3295027.
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Zhang, Bin, Yooseob Song, George Voyiadjis, Kristian Juul, Shuai Shao und Wen Jin Meng. „Texture Development and Mechanical Response in Microscale Reverse Extrusion of Copper“. In ASME 2018 13th International Manufacturing Science and Engineering Conference. American Society of Mechanical Engineers, 2018. http://dx.doi.org/10.1115/msec2018-6472.
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Axisymmetric reverse extrusion experiments were conducted on annealed Cu rod specimens to form cup-shaped structures with sidewall thicknesses ranging from ∼400 μm down to ∼25 μm. Scanning electron microscopy (SEM) and electron backscatter diffraction (EBSD) were used to examine the changes in Cu grain morphology and texture as a result of the forming operation. Pole figure (PF) and orientation distribution function (ODF) analysis of EBSD data showed the presence of the same texture components in the present small scale metal forming experiments as those observed previously in macroscale sheet metal rolling. Extrusion force – punch displacement curves were measured as a function of extruded cup sidewall thickness. The present work illustrates materials characteristics in small scale metal forming, and suggests directions of future work for bringing improved correspondence between experimentation and modeling for metal micro forming.
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Wilczynski, K., und A. Nastaj. „SSEM-AG Computer Model for Optimization of Polymer Extrusion“. In ASME 2006 International Mechanical Engineering Congress and Exposition. ASMEDC, 2006. http://dx.doi.org/10.1115/imece2006-13074.
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The optimization of an extrusion process is a conflicting, multi-objective problem. It is complicated by the number of variables (screw/die geometry, operating conditions, material data) and their non-linear relations, as well as by the opposing criteria, for example extrusion throughput and power consumption. It is difficult to find the global optimum for the process avoiding local optima. There are two approaches to solve the problem, experimental and using a mathematical model of extrusion. Optimization techniques based on an experimentation are time-consuming and very expensive. In this paper we present an optimization methodology based on the Genetic Algorithms (AG), where response surface is given by the extrusion model. A mathematical Single-Screw Extrusion Model SSEM developed at the Warsaw University of Technology is used to predict the extruder behavior, and AG approach is used for optimization. An integrated SSEM-AG system was developed to study optimization of the single-screw extrusion process. Three design criteria (output variables) are selected for optimization: maximum extrusion throughput, minimum power consumption and low melt temperature. As input variables, screw speed, barrel temperature and screw channel depth are chosen.
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Brown, E. N., G. T. Gray und C. P. Trujillo. „Influence of necking propensity on the dynamic-tensile-extrusion response of fluoropolymers“. In DYMAT 2009 - 9th International Conferences on the Mechanical and Physical Behaviour of Materials under Dynamic Loading. Les Ulis, France: EDP Sciences, 2009. http://dx.doi.org/10.1051/dymat/2009023.
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Krishnan, Neil, Jian Cao und Kuniaki Dohda. „Microforming: Study of Friction Conditions and the Impact of Low Friction/High-Strength Die Coatings on the Extrusion of Micropins“. In ASME 2005 International Mechanical Engineering Congress and Exposition. ASMEDC, 2005. http://dx.doi.org/10.1115/imece2005-81490.
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Microforming is a relatively new realm of manufacturing technology that addresses the issues involved in the fabrication of metallic microparts, i.e., metallic parts that have at least two characteristic dimensions in the sub-millimeter range. The recent trend towards miniaturization of products and technology has produced a strong demand for such metallic microparts with extremely small geometric features and high tolerances. Conventional forming technologies, such as extrusion, have encountered new challenges at the micro-scale due to the influence of ‘size effects’ that tend to be predominant at this length scale. One of the factors that shows a strong influence is friction. This paper focuses on the frictional behavior observed at various sample sizes during micro-extrusion. A novel experimental setup consisting of forming assembly and a loading stage has been developed to obtain the force-displacement response for the extrusion of pins made of brass (Cu/Zn: 70/30). This experimental setup is used to extrude pins with a circular cross-section that have a final extruded diameter ranging from 1.33 mm down to 570 microns. The experimental results are then compared to finite-element simulations and analytical models to quantify the frictional behavior. It was found that the friction condition was non-uniform and showed a dependence on the dimensions (or size) of the micropin. The paper also investigates the validity of using high-strength/ low friction die coatings to improve the tribological characteristics observed in micro-extrusion. Three different extrusion dies coated with diamond-like carbon with silicon (DLC-Si), chromium nitride (CrN) and titanium nitride (TiN) were used in the micro-extrusion experiments. All the coatings worked satisfactorily in reducing the friction and correspondingly, the extrusion force with the DLC-Si coating producing the best results.
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Alafaghani, Ala’aldin, Ala Qattawi, Julia Truong, Md Shah Jaman und Jian-Qiao Sun. „Optimizing Fused Deposition Modeling Processing Parameters Using Response Surface Method for Strong Parts“. In ASME 2020 15th International Manufacturing Science and Engineering Conference. American Society of Mechanical Engineers, 2020. http://dx.doi.org/10.1115/msec2020-8528.
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Abstract Optimizing the processing parameters of fused deposition modeling is a challenging task due to the significant number of factors that influence the quality of the fabricated parts. Therefore, optimizing the dimensional accuracy, surface roughness, or mechanical properties usually requires a considerable amount of test samples. In the presented work, the design of experiments approach was used to minimize the number of tests needed to optimize the factors. Most of the work available in literature did not investigate the interactions between the factors or their second-order effects on the strength and stiffness of fused deposition modeling parts. In this work, the effects of the layer thickness, extrusion temperature, and infill percentage are investigated and optimized to achieve the optimum strength and stiffness of the fabricated parts. The response surface method was used to investigate the interaction effects and second-order effects on the tensile strength and elastic modulus of the fabricated samples. It was found that some interaction and second-order effects exist and affect the strength and stiffness of FDM parts. Generally, increasing the extrusion temperature and infill percentage increase the tensile strength and the elastic modulus. In addition, the predicted data matches the experimental results well. However, multi-objective optimization is needed when choosing the layer thickness.
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Ansari, Ajmal I. „Post Extrusion Cooling of Multilayer Polymer Sheet on Chilled Rolls“. In ASME 2005 Summer Heat Transfer Conference collocated with the ASME 2005 Pacific Rim Technical Conference and Exhibition on Integration and Packaging of MEMS, NEMS, and Electronic Systems. ASMEDC, 2005. http://dx.doi.org/10.1115/ht2005-72459.
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To meet the stringent emission and environmental regulations, polymer sheet with as many as six layers is required for thermoformed fuel tanks used in the automotive industry. The 10 mm to 12 mm thick sheet is made using an extrusion process. Typically each polymer layer has its own hopper, screw, barrel, nozzle and extruder. During manufacturing, polymer layers are fused together within the tool and the multilayer polymer sheet leaves the extruder in a viscoelastic state. The multilayer sheet is initially cooled by passing it over chilled rolls. The final cooling of the sheet is done via natural convection to the ambient air while the sheet is transported to the cutting station at the end of the line. The cooling of the sheet on the chilled and polished rolls has a direct influence on the quality of the sheet as well as the scrap. The conductive heat transfer is primarily responsible for the cooling while the sheet is on the chilled roll. It is desired to have the smooth sheet exterior surfaces with constant thickness of each polymer layer in the cross section. Due to the numerous materials in the cross section, and associated variability of material properties, it becomes a challenging task to meet these requirements. This paper discusses the problem of the smoothness of the exterior surfaces of the extruded sheet. The “dimpled” or “orange peel” surface finish is observed to be linked to the cooling of the sheet on the chilled rolls. Experimental data and simulation results are presented that relate the formation of dimples to the local cooling rate. The variability of thermal contact resistance between the sheet surface and the chill rolls also appear to be another variable that contributes to the dimpled surface.
Berichte der Organisationen zum Thema "Responsive extrusion"
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Wijaya, Ignasius P. A., Eric Kreiger und Asuf Masud. An elastic-inelastic model and embedded bounce-back control for layered printing with cementitious materials. Engineer Research and Development Center (U.S.), Januar 2024. http://dx.doi.org/10.21079/11681/48091.
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This paper presents a finite-deformation model for extrusion-based layered printing with cementitious materials. The evolution of mechanical properties as the printed material cures and stiffens results in nonphysical reduction in the magnitude of elastic strains when standard constitutive models are employed. This elastic recovery of the printing induced deformation contradicts the experimentally observed behavior of the printed cementitious materials that harden at a nearly-frozen deformed state. A thermodynamically motivated constraint on the evolution of elastic strains is imposed on the constitutive model to remedy the nonphysical bounce-back effect. An algorithm that is based on a strain-projection technique for the elastic part of deformation is developed that complements the inelastic response given by the Drucker–Prager model. It is then embedded in a finite strain finite element framework for the modeling and simulation of cure hardening and inelastic response of the early age cementitious materials. A ghost mesh method is proposed for continuous layer-wise printing of the material without the need for intermittent mesh generation technique or adaptive remeshing methods. The model is validated via comparison with experimental data and representative test cases are presented that investigate the mathematical and computational attributes of the proposed model.