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1
Nxumalo, Mbekezeli Sibahle. "Ultrafilters and Compactification." UWC, 2020. http://hdl.handle.net/11394/7374.
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>Magister Scientiae - MScIn this thesis, we construct the ultrafilter space of a topological space using ultrafilters as points, study some of its properties and describe a method of generating compactifications through the ultrafilter space. As part of investigating some properties of the ultrafilter space, we show that the ultrafilter space forms a monad in the category of topological spaces. Furthermore, we show that rendering the ultrafilter space suitably separated results in a generation of separated compactifications which coincide with some well-known compactifications. When the ultrafilter space is rendered T0 or sober, the resulting compactifications is a stable Compactifications. Rendering the ultrafilter space T2 or Tychono results in the Stone_ Cechcompactification
2
Devlin, Barry-Patrick. "Codensity, compactness and ultrafilters." Thesis, University of Edinburgh, 2016. http://hdl.handle.net/1842/19476.
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Codensity monads are ubiquitous, as are various different notions of compactness and finiteness. Two such examples of "compact" spaces are compact Hausdorff Spaces and Linearly Compact Vector Spaces. Compact Hausdorff Spaces are the algebras of the codensity monad induced by the inclusion of finite sets in the category of sets. Similarly linearly compact vector spaces are the algebras of the codensity monad induced by the inclusion of finite dimensional vector spaces in the category of vector spaces. So in these two examples the notions of finiteness, compactness and codensity are intertwined. In this thesis we generalise these results. To do this we generalise the notion of ultrafilter, and follow the intuition of the compact Hausdorff case. We give definitions of general notions of "finiteness" and "compactness" and show that the algebras for the codensity monad induced by the "finite" objects are exactly the "compact" objects.
3
Krautzberger, Peter [Verfasser]. "Idempotent filters and ultrafilters / Peter Krautzberger." Berlin : Freie Universität Berlin, 2009. http://d-nb.info/1023817063/34.
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Boero, Ana Carolina. "Topologias enumeravelmente compactas em grupos abelianos de não torção via ultrafiltros seletivos." Universidade de São Paulo, 2011. http://www.teses.usp.br/teses/disponiveis/45/45131/tde-23082011-225107/.
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Assumindo a existência de $\\mathfrak c$ ultrafiltros seletivos dois a dois incomparáveis (segundo a ordem de Rudin-Keisler) provamos que o grupo abeliano livre de cardinalidade $\\mathfrak c$ admite uma topologia de grupo enumeravelmente compacta com uma seqüência não trivial convergente. Sob as mesmas hipóteses, mostramos que um grupo topológico abeliano quase livre de torção $(G, +, \\tau)$ com $|G| = |\\tau| = \\mathfrak c$ admite uma topologia independente de $\\tau$ que o torna um grupo topológico e caracterizamos algebricamente os grupos abelianos de não torção que têm cardinalidade $\\mathfrak c$ e que admitem uma topologia de grupo enumeravelmente compacta (sem seqüências não triviais convergentes). Provamos, ainda, que o grupo abeliano livre de cardinalidade $\\mathfrak c$ admite uma topologia de grupo que torna seu quadrado enumeravelmente compacto e construímos um semigrupo de Wallace cujo quadrado é, também, enumeravelmente compacto. Por fim, assumindo a existência de $2^{\\mathfrak c}$ ultrafiltros seletivos, garantimos que se um grupo abeliano de não torção e cardinalidade $\\mathfrak c$ admite uma topologia de grupo enumeravelmente compacta, então o mesmo admite $2^{\\mathfrak c}$ topologias de grupo enumeravelmente compactas (duas a duas não homeomorfas).Assuming the existence of $\\mathfrak c$ pairwise incomparable selective ultrafilters (according to the Rudin-Keisler ordering) we prove that the free abelian group of cardinality $\\mathfrak c$ admits a countably compact group topology that contains a non-trivial convergent sequence. Under the same hypothesis, we show that an abelian almost torsion-free topological group $(G, +, \\tau)$ with $|G| = |\\tau| = \\mathfrak c$ admits a group topology independent of $\\tau$ and we algebraically characterize the non-torsion abelian groups of cardinality $\\mathfrak c$ which admit a countably compact group topology (without non-trivial convergent sequences). We also prove that the free abelian group of cardinality $\\mathfrak c$ admits a group topology that makes its square countably compact and we construct a Wallace\'s semigroup whose square is countably compact. Finally, assuming the existence of $2^$ selective ultrafilters, we ensure that if a non-torsion abelian group of cardinality $\\mathfrak c$ admits a countably compact group topology, then it admits $2^$ (pairwise non-homeomorphic) countably compact group topologies.
5
Bishop, Gregory J. "Ultrafilters generated by a closed set of functions and K- covering sets /." The Ohio State University, 1992. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487779914823645.
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Koçak, Mahmut. "Compactifications of a uniform space and the LUC-compactification of the real numbers in terms of the concept of near ultrafilters." Thesis, University of Hull, 1994. http://hydra.hull.ac.uk/resources/hull:10782.
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Machado, Geovani Pereira. "Introdução à análise não standard." Universidade de São Paulo, 2018. http://www.teses.usp.br/teses/disponiveis/45/45131/tde-18022019-171451/.
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A área conhecida como Análise Não Standard consiste na aplicação dos métodos da Teoria dos Modelos e da Teoria dos Ultrafiltros para a obtenção de extensões peculiares de sistemas matemáticos infinitos. As novas estruturas construídas segundo esse procedimento satisfazem ao Princípio da Transferência, uma propriedade de suma importância e influência a qual afirma que as mesmas sentenças de primeira ordem com quantificadores limitados são verdadeiras para o sistema original e a sua extensão. Concebida em 1961 por Abraham Robinson e aprimorada por vários matemáticos nos anos subsequentes, tal área de pesquisa provou ser bastante proveitosa e esclarecedora para diversas outras partes da Matemática, como a Topologia, a Teoria das Probabilidades, a Análise Funcional e a Análise Complexa. Manifesta-se uma reavaliação da Teoria dos Domínios Ordenados seguida de um tratamento completo e gradual das fundações da Análise Não Standard assumindo a perspectiva dos Monomorfismos Não Standard, onde adota-se como metateoria a teoria dos conjuntos de Neumann-Bernays-Gödel com o Axioma da Escolha. A fim de impulsionar a assimilação da metodologia abordada, o estudo explora as propriedades do corpo não arquimediano dos números hiper-reais de maneira intuitiva e informal, utilizando-se destas para revelar demonstrações alternativas e relativamente diretas de alguns dos principais resultados do Cálculo Diferencial e Integral, como o Teorema do Valor Intermediário, o Teorema de Bolzano-Weierstrass, o Teorema do Ponto Crítico, o Teorema da Função Inversa e o Teorema Fundamental do Cálculo.The field known as Non-standard Analysis consists in the application of the methods of Model Theory and Ultrafilter Theory to the attainment of peculiar extensions of infinite mathematical systems. The new structures produced under that procedure satisfy the Transfer Principle, a property of the utmost importance and influence which states that the same first-order sentences with bounded quantifiers are true for the original system and its extension. Conceived in 1961 by Abraham Robinson and improved by a number of mathematicians in the following years, such area of research has proved to be very fruitful and illuminating to many other parts of Mathematics, such as Topology, Probability Theory, Functional Analysis and Complex Analysis. The work presents a reexamination of the Theory of Ordered Domains followed by a thorough and gradual treatment of the foundations of Non-standard Analysis under the perspective of Non-standard Monomorphisms, where Neumann-Bernays-Gödels set theory with the Axiom of Choice is adopted as metatheory. In order to boost the assimilation of the methodology put forward, the study explores the properties of the non-archimedean field of hyperreal numbers in an intuitive and informal fashion, employing them to reveal alternative and relatively direct proofs of some of the main results of Differential and Integral Calculus, such as the Intermediate Value Theorem, the Bolzano-Weierstrass Theorem, the Extreme Value Theorem, the Inverse Function Theorem and the Fundamental Theorem of Calculus.
8
Eliasson, Jonas. "Ultrasheaves." Doctoral thesis, Uppsala : Matematiska institutionen, Univ. [distributör], 2003. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-3762.
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Quiroga, Jury Fabiana Castiblanco. "Topologias de grupo enumeravelmente compactas: MA, forcing e ultrafiltros seletivos." Universidade de São Paulo, 2011. http://www.teses.usp.br/teses/disponiveis/45/45131/tde-07092012-163026/.
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É bem conhecido o fato de que todo grupo compacto tem sequências não triviais convergentes. A existência de grupos enumeravelmente compactos sem sequências não triviais convergentes, foi provada usando axiomas adicionais à axiomática usual ZFC: A. Hajnal e I. Juhász sob CH, E. K. van Douwen sob MA, A. H. Tomita sob MA(sigma-centrada) e R.E. Madariaga-Garcia e A. H. Tomita usando ultrafiltros seletivos. Neste trabalho, estudaremos algumas construções recentes relacionadas com as citadas acima, usando o Axioma de Martin, ultrafiltros seletivos e forcing. Essas construções estão relacionadas com algumas questões indicadas por A.D. Wallace, E. van Douwen, M. Tkachenko, D. Dikranjan e D. ShakhmatovIt is well known that every compact group has non-trivial convergent sequences. The existence of countably compact groups without non-trivial convergent sequences was proved using extra set-theoretical assumptions: A. Hajnal and I. Juhasz under CH, E. K. van Douwen under MA, A.H.Tomita under MA(centered) and R.E.Madariaga-Garcia and A.H. Tomita using a selective ultrafilter. I n this work, we study some recent constructions related to the ones given above using Martin Axiom, selective ultrafilters and forcing, related to questions raised by A.D. Wallace, E. van Douwen, M. Tkacenko, D. Dikranjan and D. Shakhmatov.
10
Ruotsalainen, V. (Vesa). "Nephrin:role in the renal ultrafilter and involvement in proteinuria." Doctoral thesis, University of Oulu, 2004. http://urn.fi/urn:isbn:9514273494.
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Abstract
Congenital nephrotic syndrome of the Finnish type (NPHS1, CNF) is an autosomal recessive disease that affects 1:8000 newborns in Finland. NPHS1 is characterised by heavy proteinuria already in utero and typical signs of nephrotic syndrome (NS) are present at or soon after birth. Due to the evident absence of extrarenal symptoms, NPHS1 has been considered a model disease for NS.
In this study, the NPHS1 locus on chromosome 19q13.1 was sequenced and analysed with computer programs to identify new genes in the region. Genes were further characterised and sequenced from NPHS1 patient samples, as well as from controls. Analysis of the data resulted in the identification of the affected gene with two mutations that were found to explain 94% of the Finnish NPHS1 cases. The NPHS1 gene was found to encode a novel single-pass transmembrane protein, termed nephrin, which belongs to the immunoglobulin superfamily of cell adhesion molecules.
The NPHS1 gene was cloned and recombinant nephrin fragments were produced in prokaryotic and eukaryotic expression systems. These fragments were used to raise antibodies that were utilized to characterise the spatial and temporal expression of nephrin in kidney glomeruli. Nephrin was localised by electron microscopy (EM) in ladder-like structures of the early junctional complexes of developing columnar podocytes at the capillary stage. In mature glomeruli, nephrin was localised to the slit diaphragm (SD) between adjacent glomerular podocyte foot processes.
In order to investigate the more general involvement of nephrin in proteinuric disease, its expression was studied in primary acquired NS by immunofluorescence microscopy. The level of nephrin expression was found to be significantly reduced in membranous glomerulonephritis, minimal change disease and in focal segmental glomerulosclerosis.
The known effects of nephrin mutations, together with the structure predicted from its sequence and localisation of the protein to the SD, emphasizes its indispensable role in maintaining the integrity of the glomerular filtration barrier. The glomerular basement membrane has long been considered to possess the size-selective filtration property of the filtration barrier. However, the identification of nephrin in the SD, as well as its alterations in proteinuria, has led us to reconsider SD as the final decisive size-selective filter.
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Ocampo-Garcia, Jorge Ricardo. "Cottage Cheese from Ultrafiltered Skimmilk by Direct Acidification." DigitalCommons@USU, 1987. https://digitalcommons.usu.edu/etd/5344.
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Pasteurized skimmilk at 4°C was acidified to pH 5.8 with 85.5% phosphoric acid (136g H3Po4;100 kg skimmilk), then warmed to 54°C and ultrafiltered to a protein concentration 9.1 ± 0.2%. The retentate was heated to 76.5°C for 16 s then cooled to 2°C. Phosphoric acid (85.5%) was added at a rate of 3.41g per kg retentate. The acidified retentate was slowly warmed to 29.5 °C (3°C/5 min) when the pH was checked. The pH at this point was no lower than 5.4. Heating was continued until a temperature of 32.2°C was reached. Glucono delta lactone was added to the retentate (17.6 g/kg retentate) and left undisturbed for approximately 80 min. The curd was cut at pH 4.7 with 0.64 cm curd knives and allowed 10 min for syneresis. Permeate obtained from the same lot of milk was acidified to pH 4.8 (66 g H3Po4;100 kg permeate), then added to the curd at 32.2°C (three parts permeate to four parts retentate) and used as a cooking vehicle. The curd was cooked to 59°C in 90 min. The curd was held at 59°C for 10 min, drained and washed once with ice water. Cream dressing containing 12.5% fat and 3% salt was used at the rate of two parts curd to one part dressing.
Control cottage cheese was produced by a direct acid method from the same skimmilk used to produce ultrafiltered curd.
Use of ultrafiltered skimmilk retentate for cottage cheese making resulted in 2.24% more curd (corrected to 20% solids) and 2.24% more curd per kg original milk protein than the control. However, satisfactory firmness in UF curd required slightly more than 20% solids in the final product. Sensory evaluations indicated that creamed cottage cheese was not significantly different (p
12
Shammet, Khalid Mohamed. "Manufacture of White Soft Cheese from Ultrafiltered Whole Milk Retentate." DigitalCommons@USU, 1986. https://digitalcommons.usu.edu/etd/5334.
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Manufacture of white soft cheese from ultrafiltered whole cows• milk involved acidification of pasteurized homogenized whole milk to pH 6.0 with phosphoric or citric acid. The preacidified milk was ultrafiltered at 54 °C until 60% of original milk weight was removed as permeate, diafiltered with deionized water equal to 38.5% of the original milk and concentrated by UF (4.8 fold) to pre-cheese (38% total solid). The pre-cheese was heated to 76.7°C/16 sec, 71 .l°C/l6 sec (HTST) and 7l.l°C/l5 min (controlled water bath), inoculated with 2% starter culture (Streptococcus cremoris), renneted (10 ml/100 lb retentate) and placed in one pound plastic containers in which coagulation took place (8-10 min). Salt (1 .5%) was added on the top of parchment paper placed under the lid, and the curd was incubated at 85°F. The most acceptable cheese was from ultrafiltered retentate heated for 16 sec at 76.7°C before cheese making. Organoleptic tests showed that samples highest in calcium content ranked highest in acceptability. Acidification with citric acid removed more calcium than phosphoric acid and resulted in softer cheese than the control cheese (non-acidified). Slight bitterness was observed when excessive starter and low salt (NaCl) concentration were used. Addition of salt to the retentate prior to heating caused thickening of the retentate before 70°C was reached. Extending the heating time increased the tendency toward mealiness in the cheese.
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Wehrung, Friedrich. "Non absoluité de l'injection élémentaire associée à un ultrafiltre complet." Grenoble 2 : ANRT, 1987. http://catalogue.bnf.fr/ark:/12148/cb376107266.
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Wehrung, Friedrich. "Non absoluite de l'injection elementaire associee a un ultrafiltre complet." Caen, 1987. http://www.theses.fr/1987CAEN2008.
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L'outil essentiel a l'etude des consequences en theorie des ensembles de l'existence d'un cardinal mesurable est la consideration des injections elementaires associees, et en particulier des points fixes dans les ordinaux de ces injections elementaires. Quand un ordinal donne n'est pas point fixe de l'injection elementaire associee a un ultrafiltre complet sur un certain cardinal mesurable, nous dirons qu'il est bouge par ce cardinal mesurable. K. Kunen montra en 1973, de facon essentiellemnt non constructive, que tout ordinal n'est bouge que par un nombre fini de cardinaux mesurables. Nous presentons ici une preuve de ce resultat en connexion etroite avec la finitude du support de tout element d'une ultrapuissance iteree. En relation avec l'obstruction rencontree a la recherche d'une preuve contructive du resultat precedent, nous examinons ensuite quand peuvent se produire des cas de non absoluite du fait qu'un cardinal mesurable donne bouge un certain ordinal pour des modeles interieurs de theorie des ensembles, sur lesquels nous ferons diverses hypotheses; puis nous comparerons la force des enonces obtenus a celles d'hypotheses de grand cardinal connues, apres en avoir donne dans certains cas des contreparties en termes d'ordinaux indiscernables. La theorie des indiscernables -sur les versions relativisees des ensembles constructibles- que nous utiliserons sera presentee ici dans un contexte tout a fait general et independant des problemes poses ci-dessus. Certains resultats sans analogue dans la theorie classique se degageront alors, le plus utile etant un resultat "d'invariance par injection elementaire" de l'existence d'indiscernable sur les modeles consideres
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Solorio, Hector Alejandro. "Heat-Induced Gelation of Ultrafiltered Whole Milk Concentrate and Product Applications." DigitalCommons@USU, 1999. https://digitalcommons.usu.edu/etd/5469.
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The heat-induced gelation properties of ultrafiltered (UF) whole milk concentrate were studied under different physical and chemical conditions. total solids concentration, homogenization pressures, heating temperatures, and heating times were found to have a positive correlation with gel strength. The addition of calcium chloride, sodium chloride, or trisodium citrate produced gels of higher strengths and textural properties than the gels obtained with non-salt-treated concentrate. Calcium chloride produced the strongest gels with a cheese-like texture and poor spreadability. Sodium chloride produced gels of intermediate strength with a firm, elastic texture and poor spreadability. Trisodium citrate produced the softest gels with a smooth, creamy texture and good spreadability.
A shelf stable 40% total solids UF concentrate was manufactured using ultra-high temperature (UHT) processing by direct steam injection. The pourable concentrate had a shelf life of 75 to 90 days at 23°C and did not have the ability to produce heat-induced gels after a second heating. Addition of calcium chloride, sodium chloride, or trisodium citrate restored the heat-induced gelation of the retentate. However, the gels were weaker and presented different characteristics than did the gels from non-UHT-treated concentrate.
Transmission electron microscopy (TEM) studies revealed a relationship between gel firmness and gel ultrastructure of the heat-induced gels. The gels consisted of a network of casein micelles connected with strands of a less dense protein material. The tighter the network the stronger the gel strength. High heating temperatures and calcium chloride addition caused fusion of the casein micelles int he network. Sensory evaluation of two prototype gelled desserts by a general consumer population showed a good potential for the use of the heat-induced gelation property of UF-concentrated whole milk in the development of new gelled dessert applications.
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Baker, Joshua Dale. "Near Single-Molecule SERS-Based Detection Using Ultrafiltered, Unfunctionalized Silver Nanoparticles." Wright State University / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=wright1344523437.
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Chicourrat, Monique. "Extensions de prétopologies et de proximités dans l'ensemble des ultrafiltres : résolution du problème de Riesz." Perpignan, 1992. http://www.theses.fr/1992PERP0139.
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Cette these se situe dans le contexte des travaux de thron (1973), chattopadhyay (1988), csaszar (1986). . . Reprenant des idees primordiales exposees par riesz (1908) et developpees par efremovic (1951) et bognar (1962). Nous caracterisons les relations entre parties d'un ensemble x, admettant une extension de riesz, c'est-a-dire telles qu'il existe un ensemble y contenant x, muni d'une pretopologie, pour lesquels, notamment, deux parties a et b de x seront liees par la relation de depart si et seulement si les fermetures pretopologiques de a et b dans y s'intersectent. Et nous caracterisons tout particulierement les relations qui admettent des extensions de riesz regulieres (cas ou la pretopologie sur y peut en fait etre une structure topologique reguliere). Pour cela, nous montrons entre autres que de telles extensions y peuvent etre constituees d'ultrafiltres (sur x). La methode utilisee pour aborder ce probleme est donc differente de celles employees par csaszar, chattopadhyay. . . Elle est basee sur l'analyse de la connexion de galois naturelle existant entre relations entre parties de x et relations entre ultrafiltres sur x: nous etudions de facon systematique la nasse (certaine relation entre ultrafiltres; haddad, 1962) associee a une relation entre parties de x; et les caracterisations precedentes s'obtiennent alors par l'intermediaire de resultats portant sur les nasses
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Schardijn, Amy. "AN INTRODUCTION TO BOOLEAN ALGEBRAS." CSUSB ScholarWorks, 2016. https://scholarworks.lib.csusb.edu/etd/421.
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This thesis discusses the topic of Boolean algebras. In order to build intuitive understanding of the topic, research began with the investigation of Boolean algebras in the area of Abstract Algebra. The content of this initial research used a particular notation. The ideas of partially ordered sets, lattices, least upper bounds, and greatest lower bounds were used to define the structure of a Boolean algebra. From this fundamental understanding, we were able to study atoms, Boolean algebra isomorphisms, and Stone’s Representation Theorem for finite Boolean algebras. We also verified and proved many properties involving Boolean algebras and related structures.
We then expanded our study to more thoroughly developed theory. This comprehensive theory was more abstract and required the use of a different, more universal, notation. We continued examining least upper and greatest lower bounds but extended our knowledge to subalgebras and families of subsets. The notions of cardinality, cellularity, and pairwise disjoint families were investigated, defined, and then used to understand the Erdös-Tarski Theorem.
Lastly, this study concluded with the investigation of denseness and incomparability as well as normal forms and the completion of Boolean algebras.
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Orme, Brian J. "Improving Fat Retention and Texture in Low-Moisture Cheese Manufactured from Ultrafiltered Milk." DigitalCommons@USU, 1998. https://digitalcommons.usu.edu/etd/5453.
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Three serious problems have been experienced in the manufacture of low moisture cheese using ultrafiltration (UF)- high fat-loss, excessive moisture retention, and poor cheese texture. In this work the causes of these problems were identified, and means of overcoming them were developed.
Coagulation and cheese-making experiments indicated that UF concentration of milk shifts the control of rennet coagulation toward the casein micelle collision rate and away from rennet activity, resulting in formation of a rough-textured curd structure that resists syneresis. Use of 4x whole milk retentate, instead of 5x, improved rennet curd structure, syneresis, and UF cheese texture without reducing protein retention in the cheese. Use of increased rennet and reduced set temperature (26°C) also improved curd structure, syneresis, and cheese texture. Washing of the rennet curd prepared from 4x milk retentate during cheese-making, instead of diafiltration of retentate, was found to improve cheese texture, and cheese moisture below 39% was achieved.
UF retentate was inconsistent as a starter medium because it offered no protection against bacteriophage proliferation, and the growth of some strains of Lactococcus lactis was impaired in UF retentate. Commercial, internally-buffered pH-controlled starter media were more consistent than fermented retentate starter when used for making cheese from 4x retentate.
Low-pressure homogenization of milk at a temperature between 37°C and 45°C increased fat recovery in UF cheese made from 4x ultrafiltration concentrated milk with minimal damage to cheese texture and syneresis. A procedure was developed for the manufacture of quality, high-yield, low-moisture cheese from 4 times ultrafiltration concentrated whole milk. Fat retention in the cheese was 95% and protein retention was 85%
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Dargan, Richard Alan. "Properties of Low-fat Yogurt Made From Ultrafiltered and Ultra-high Temperature Treated Milk." DigitalCommons@USU, 1992. https://digitalcommons.usu.edu/etd/5389.
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Yogurts were made from intermediate-high temperature (100, 110, 120, and 130°C for 4 or 16 s), ultra-high temperature (140°C for 4 or 16 s), and vat heat (82°C for 20 min) treatments of skim milk fortified to 5% protein by either ultrafiltration or the addition of nonfat dry milk (NOM). Whey protein denaturation in heated milks increased with temperature and holding time from indirect plate heating and was highest in vat-heated milks. Whey protein denaturation and yogurt water-holding capacity increased with protein levels in the fortified milks compared to skim milk. Penetrometer gel strength and stirred viscosity in 21 day-old yogurt made from heated ultrafiltered skim milk exceeded those of yogurts made from NOM-fortified skim milk, even though the NOM yogurts contained more solids (13.0 vs 11.4%). Maximum gel strength and viscosity, and least syneresis of yogurts from ultrafiltered and NOM fortified yogurts occurred following intermediate-high temperature treatments of 1 00°C for 16 s, 110°C for 4 or 16 s, and 120°C for 4 s. There was significantly lower whey protein denaturation at these intermediate-high temperatures compared to UHT or vat heating. Gel strength and viscosity were lower and syneresis greater in yogurts from ultrafiltered or NOM-fortified skim milk following UHT treatment compared to yogurts made with intermediate-high temperature treatments or vat heating. The water-holding capacity of yogurts from fortified milks treated at intermediate-high temperatures was comparable to that of yogurts from vatheated milks. Fortification by ultrafiltration, to lower total solids (and without use of stabilizers) resulted in yogurt with higher gel strength and viscosity, and reduced syneresis compared to yogurt from NOM fortification. Yogurt prepared by intermediate-high temperature treatment had comparable or better gel strength and viscosity, and reduced syneresis compared to yogurt prepared by traditional vat heating.
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Van, Name Joseph Anthony. "Boolean Partition Algebras." Scholar Commons, 2013. http://scholarcommons.usf.edu/etd/4599.
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A Boolean partition algebra is a pair $(B,F)$ where $B$ is a Boolean
algebra and $F$ is a filter on the semilattice of partitions of $B$ where $\bigcup F=B\setminus\{0\}$. In this dissertation, we shall investigate the algebraic theory of Boolean partition algebras and their connection with uniform spaces. In particular, we shall show that the category of complete non-Archimedean uniform spaces
is equivalent to a subcategory of the category of Boolean partition algebras, and notions such as supercompleteness
of non-Archimedean uniform spaces can be formulated in terms of Boolean partition algebras.
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Raynes, Ronald Michael. "Influence of Process Parameters in the Manufacture of Cottage Cheese Curd from Ultrafiltered Skim Milk." DigitalCommons@USU, 1992. https://digitalcommons.usu.edu/etd/5391.
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A processing procedure for the manufacture of directly acidified cottage cheese curd from 16% total solids ultrafiltered retentate was developed. The effects of preacidification of skim milk before ultrafiltration and heat treatment of retentate were investigated to improve the functional and sensory qualities of retentate curd.
Retentate directly acidified with phosphoric acid and glucono-delta-lactone to pH 4.7 formed a dense, rubbery curd that could not be handled well in a vat. A heat treatment of 71.1°C for 30 min applied to the retentate resulted in a curd with acceptable handling properties. However, this heat treatment caused the curd to shift in pH, become translucent in appearance, and have a pasty texture. Preacidification of the skim milk to pH 5.8 12 h prior to ultrafiltration, and a less severe heat treatment of 71.1°C for 6 min made a stable curd with good sensory quality.
A 3 x 4 x 3 randomized split block design experiment was done to test the effects of preacidification and heat treatment on the properties of retentate curd. Skim milk was pasteurized at 62.8°C for 30 min and split into three lots which were unacidified, phosphoric acid added to pH 6.2, and phosphoric acid added to pH 5.85. The three lots of skim milk were ultrafiltered at 54.4°C to 16% total solids. Each lot was divided into four treatments which were unheated, heated to 71.1°C for 7 s, 76.7°C for 7 s, and 82.2°C for 7 s. Each vat was replicated three times. Cottage cheese pH, total solids, and six sensory attributes were measured. Finished cottage cheeses were evaluated by an expert panel of five judges. Total solids, protein content, and fines content of the whey were also measured. Preacidification treatment at pH 6.2 enhanced curd structure, which increased solids recovery, reduced fines, and improved curd appearance, firmness, and texture. Heat treatments caused softening of the curd and increased moisture content in the curd. Excessive heat treatment caused shattering, fines, and mealiness. The best curd from the experiment was produced from pH 6.2 retentate heat treated at 71.1°C for 7 s. Whey proteins decreased in wheys from retentates heat treated at 76.7°C for 7 sand 82.2°C for 7 s. The effects of heat treatment were more pronounced with increasing acidification.
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Pope, Brent Karl. "Factors Affecting Growth of Proteinase Positive and Proteinase Negative Streptococcus cremoris UC310 in Ultrafiltered Milk Retentate." DigitalCommons@USU, 1987. https://digitalcommons.usu.edu/etd/5356.
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Whole milks were adjusted to pH 5.8, 6.2, or 6. 7 with HCl and batch pasteurized at 63°C for 30 min. Each was concentrated 5:1 (40% total solids) through a single tube polysulfone membrane Abcor ultrafiltration unit. Lactose (L), casein hydrolysate (CH), and one of two brands of yeast extract (YE1, YE2) were added into cooled retentates at 0.1, 0.3, 0.5, 0. 7 or 0.9% and equilibrated overnight at 4°C. Five percent proteinase positive (Prt+) Streptococcus cremoris UC 310+ (v/w) milk based culture was added. Unfortified retentate was also inoculated with 0.1, 0.3, 0.5, 0. 7 or 0.9% starter and pH readings were taken on all samples for 24 h during incubation at 23°C. Similar substrates were inoculated with proteinase negative (Prt-) S. cremoris UC 310-.
Lactose had no significant effect on acid production. Casein hydrolysate had a slight positive effect. Yeast extract had a significant effect at all preacidification levels and a significant difference was also noticed between the brands. Mean times required for the proteinase positive culture to reach pH 5.1 in 5x retentate from milk acidified to pH 5.8 were 24, 12, 10, 10, and 24 h for L, CH, YE1, YE2, and the control respectively. Proteinase negative variants of this strain had mean times of >24 h, 14 h, 11 h, 11 h, and >24 h respectively. These time differences were significantly different between Prt+ and Prt- variants. A minimum concentration of 0.2% yeast extract produced the most stimulation while greater quantities provided no additional benefit. Taste panelists were unable to detect yeast extract in retentates fermented by either culture variant.
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Piña, Claribet. "Une classification topologique du type Ramsey des ordinaux dénombrables." Sorbonne Paris Cité, 2015. http://www.theses.fr/2015USPCC097.
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Dans cette thèse, nous regardons une extension de non premier ordre de la Théorie de Ramsey. Il s'agit d'un domaine qui étend le calcul classique des partitions de Ramsey aux espaces topologiques. Dans le cadre des partitions d'espaces topologiques, les versions topologiques des relations \alpha\rightarrow(\beta)^n_{\mu,\flambda} sont l'objet d'étude. Formellement, étant donnés deux espaces topologiques X et Y, n un nombre entier positif et \lambda< \mu deux cardinaux, une relation de partition, X\rightarrow(\topo\;Y)^n_{ \mu,\lambda} désigne le fait que pour chaqur coloration f:[X]^n\longrightarrow\mu, il existe H\subseteq X homéomorphe à Y tel que f prenne au plus \lambda valeurs dans [H]^n. On a par example obtenu les relations suivantes : \forall 1 >1,\omega^\omega\rightarrow (\topo\,\omega^2+1)^2_{1,7} \forall k,1 >1,\omega^{ \omega^k} \rightarrow (\topo\,\omega^2+1)^2_{1,6} et \forall 1 >1, \ omega^{\omega^omega} \rightarrow ( \topo\, \ omega^2+1)^2_{1,4}In this thesis we look a non first-order extension of Ramsey Theory. This is an area which extends the classical Ramsey partition calculus to topological spaces. In partition of topological spaces, the topological versions of the relations \alpha\rightarrow(\beta)^n_{\mu,\lambda} are studied. Formally speaking, given X and Y two topological spaces,. N a positive integer and \lambda<\mu cardinals, a partition relation X\rightarrow(\topo\;Y)^n_{\mu,\lambda} denotes the fact that for every coloring f:[X]^n\longrightarrow \mu, there is H\subseteq X homeomorphic to Y such that f takes at most \lambda values on [H]^n. For example, we obtained the following relations : \forall 1 >1,\omega^\omega\rightarrow (\topo\,\omega^2+1)^2{1,7} \forall k,1>l,\omega^{\omega^k} \rightarrow (\topo\,\omega^2+1)^2_{1,6} et \forall 1 >1,\omega^{ \omega^omega} \rightarrow (\topo\,\omega^2+1)^2_{1,4}
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Marian, Maria Vianei. "Rela??o do volume de ultrafiltra??o e sobrevida em pacientes incidentes em di?lise peritoneal." Pontif?cia Universidade Cat?lica do Rio Grande do Sul, 2012. http://tede2.pucrs.br/tede2/handle/tede/1700.
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Previous issue date: 2012-06-22Introduction: Peritoneal dialysis ultrafiltration failure is a functional abnormality associated with increased risk of death and technique failure. Daily ultrafiltration volume early on therapy may predict patient and technique survival. Objective: to determine the relationship between to presence of risk factors, daily ultrafiltration volume, patient and technique survival. Patients and Method: Data were extracted from the observational, multicenter, BRAZPD cohort study. From a population of 2419 suitable patients, 977 incident patients were selected. At the three-month therapy interval, demographic, clinical and technical variables were appraised and daily ultrafiltration volume was analyzed by quartiles (1st: ≤ 700 ml; 2nd: > 700 ml up to ≤ 1100 ml; 3rd: > 1100 ml up to < 1600 ml; 4th: ≥ 1600 ml), as were its changes at the sixth and twelfth follow-up months. Two outcomes were considered : death and technique failure, which were analyzed till the 30th therapy month. Comparison between groups, correlations, patient and technique uni and multivariate survival analyses, using Kaplan-Meier technique and Cox regression analysis, were performed. Results: Age (HR=1.038; 95% CI: 1.027-1.049; P<0.01), diabetes (HR=1.416; 95% CI: 1.043-1.922; P=0.03) and number of co-morbidities (HR=2.687; 95% CI: 1.336-5.407; P<0,01) were directly associated with increased patient mortality. The 4th ultrafiltration quartile related with higher patient and technique survival (P=0.02 and P=0.10, respectively); peritonitis had a strong negative effect upon therapy maintenance (HR=3.459; 95% CI: 2.218-5.394; P<0.01). Conclusion: young, non-diabetic patients had increased chance for survival. High ultrafiltration volumes promoted patient and technique survival. Peritonitis significantly reduced the likelihood of technical success.
Introdu??o: A falha de ultrafiltra??o na di?lise peritoneal ? uma anormalidade funcional associada a risco aumentado para morte e para falha t?cnica. O volume di?rio de ultrafiltra??o, aos tr?s meses de terapia, pode ser fator de risco e preditor precoce para sobrevida de paciente e t?cnica. Objetivo: determinar a rela??o entre a presen?a de fatores de risco, volume di?rio ultrafiltrado e sobrevida de paciente e terapia. Pacientes e M?todo: estudo de coorte baseado em dados do estudo BRAZPD, multic?ntrico, observacional. Foram inclu?dos 977 pacientes incidentes, dentre 2419 eleg?veis. Aos tr?s meses de terapia analisaram-se vari?veis demogr?ficas, cl?nicas e t?cnicas. O volume di?rio de ultrafiltra??o foi analisado por quartis, (1? quartil: ≤ 700 ml; 2? quartil: > 700 ml e ≤ 1100 ml; 3? quartil: > 1100 ml e < 1600 ml; 4? quartil: ≥ 1600 ml, assim como sua varia??o aos seis e doze meses de seguimento. Dois desfechos foram contemplados: morte e falha t?cnica, analisados at? 30 meses de terapia. Compara??es entre grupos, correla??es bem como an?lise univariada de sobrevida - de paciente e t?cnica - foi feita pela t?cnica de Kaplan-Meier e multivariada por regress?o de Cox. Resultados: idade (HR=1,038; IC 95%: 1,027-1,049; P<0,001), Diabetes Mellitus (HR=1,416; IC 95%: 1,043-1,922; P<0,026) e n?mero de comorbidades (HR=2,687; IC 95% -1,336-5,407; P<0,01) foram diretamente associados com mortalidade aumentada do paciente. O quarto quartil de ultrafiltra??o associou-se a maior sobrevida do paciente e da t?cnica (P=0,02 e P=0,10, respectivamente); a ocorr?ncia de peritonite teve impacto negativo para manuten??o da terapia (HR=3,459; IC 95%: 2,218-5,394; P<0,01). Conclus?o: pacientes jovens, sem diabetes tiveram maior chance de sobrevida. Ter alto volume de ultrafiltra??o foi favor?vel ? sobrevida de pacientes e da t?cnica. A ocorr?ncia de peritonite reduziu significativamente a chance de sucesso da t?cnica.
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Yousif, Bashir H. "Effects of Heat Treatment of Ultrafiltered Milk on its Rennet Coagulation Time and on Whey Protein Denaturation." DigitalCommons@USU, 1991. https://digitalcommons.usu.edu/etd/5379.
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The purpose of this research was to determine the effects of heating (including heating to ultra-high temperatures) homogenized ultrafiltered whole and skim milks on whey protein denaturation and milk's subsequent rennet coagulation properties: coagulation time, curd firmness, and microstructure.
Whole and skim milk samples were ultrafiltered using a spiral wound ultrafiltration membrane system. Samples were preheated to 72°C for 58 s, held for 8 s then heated to 72, 89, 106, 123, or 140°C for more than 97 sand held for 4 s. The milk was then cooled to 60°C and homogenized, further cooled to 30°C, packaged into 120 ml sterile containers, and refrigerated overnight. Rennet coagulation time and curd firmness were monitored using a Formagraph . Milk and gel samples were fixed in 2.5% glutaraldehyde solution and examined by electron microscopy. Whey protein denaturation was determined by precipitating casein at pH 4.6 with .lN HCl and measuring protein content in the filtrate by the Kjeldahl procedure.
Rennet coagulation time of milk increased as processing temperature was increased. Gel strength decreased with an increase in processing temperature. Ultrafiltration shortened rennet coagulation time and increased gel firmness. Ultra-high- temperature- heated whole and skim milks did not coagulate upon addition of rennet, but their concentrated counterparts did. Rennet coagulation of the concentrated milks was delayed by heating. Samples treated with ultra-high-temperature formed only a weak gel. The casein micelles in milk increased in size as a function of increasing processing temperature and concentration by ultrafiltration. Additional protein material adhered to the casein micelles after high-temperature processing and was especially noticeable in the samples treated with ultra-high-temperature. Whey protein denaturation increased as a function of increased heating temperature. The heated concentrated milks had higher levels of protein denaturation than the heated unconcentrated ones.
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Alleyne, Mark Christopher. "Fate of β-Lactoglobulin, α-Lactalbumin, and Casein Proteins in Ultrafiltered Concentrated Milk after Ultra-high Temperature Processing." DigitalCommons@USU, 1994. https://digitalcommons.usu.edu/etd/5405.
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The problem of age gelation in ultra-high temperature (U1IT) sterilized milk retentate (ultrafiltered 3x concentrated) is investigated in this work. Transmission electron microscopy (1EM), utilizing the microcube encapsulation technique and protocols for immunolocalization of milk proteins, provides insight into the phenomenon of age gelation ofUHT-sterilized, ultrafiltered (UF) milk retentate. Primary antibodies (specific for the native as well as the complexed forms of milk proteins) and secondary antibodies (conjugated to gold probes) are used to elucidate the positions of the milk proteins in various samples of milk from the stage of milking through UHT sterilization and storage for 12 months, by which time gelation had occurred. The movement of the milk proteins is charted and these data are used to determine the role of the proteins in age gelation of UHT-sterilized UF milk retentate.
Heat-denatured β-lactoglobulin and α-lactalbumin form complexes within the serum as well as with the casein components of the micelles. UHT sterilization not only denatures β-lactoglobulin and α-lactalbumin, but catalyzes the reaction of these whey proteins and K-casein, leading to the successful formation of the complex. Complexing of β-lactoglobulin and K-casein competitively weakens the complex of K-casein to other casein fractions of the micelle. This leads to migration of K-casein from the micelle to the serum, compromising the role of K-casein in stabilizing the casein proteins within the micellar moiety. The time-dependent loss of K-casein from the micelle would expose the calcium-insoluble micellar αs1-casein and β-casein to the serum calcium. Subsequent to this, some αs1-casein and β-casein are also released from the micelles, and gelation of the milk occurs. No information was obtained on location of αs2-casein. The release of K-casein from the micelles thus apparently represents the critical factor in the phenomenon of age gelation in UHT-sterilized milk concentrates.
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Moiseeva, Elena S. "Manufacture, Shelf Stability, and Acceptability of Aseptically Packaged, Unripened Soft Cheese Produced by Post-Ultra-High Temperature Acidulant Injection of Ultrafiltered Milk Concentrate." DigitalCommons@USU, 1996. https://digitalcommons.usu.edu/etd/5430.
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This study investigated the manufacturing procedures and texture attributes of direct acid set of an unripened, shelf-stable cheese variety produced by the combined technologies of ultrafiltration and ultra-high temperature processing. Product evaluation included physical and chemical properties such as gel strength, syneresis, pH, moisture, protein, and fat. Whole milk was concentrated by ultrafiltration to 30, 35, and 40% total solids. Milk retentate was ultra-high temperature-processed by preheating to 65 or 77°C, sterilized at 141°C for 4 s by direct steam injection, flash cooled to approximately 62 or 72°C, homogenized in two stages at either 13.8/2.1 or 27.6/4.1 MPa, cooled to 38°C, and aseptically packaged. iv sterilized sodium chloride was aseptically added and dissolved in the ultra-filtrated and ultra-high temperature processed retentate to produce .5% final concentration. Autoclaved solutions of citric and lactic acids, or glucono-delta-lactone were added aseptically to the salted retentate to form a soft gel by lowering the pH range from 4.3 to 4.6. The coagulated retentates were stored at room temperature for 6 months. The effects of total solids, homogenization pressures, preheat temperatures, acidulants, and storage time on selected physicochemical properties of the acid gels were determined.
Taste panels evaluated selected soft cheese characteristics after 6 months' storage. No statistically significant effect of the total milk solids level on gel firmness was observed. High homogenization pressure and the interaction of high preheat temperature and homogenization pressure produced significantly firmer gel and caused less syneresis. Acidulant types influenced significantly gel strength, syneresis, appearance, and texture. Soft cheeses prepared with citric acid were firmer than those acidified with lactic acid or gluconodelta-lactone. Lactic acid samples produced more syneresis than citric acid cheese samples. Cheese samples prepared with glucono-delta-lactone had the smoothest and least grainy texture, shiny appearance, little or no wheying-off, and a gel strength intermediate between the two other acidulants.
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Barros, Filho Marcos Andr? Capitulino de. "Influ?ncia da press?o e da vaz?o de concentrado sobre o desempenho de ultrafiltra??o no p?s-tratamento de esgotos." Universidade Federal do Rio Grande do Norte, 2015. http://repositorio.ufrn.br/handle/123456789/20782.
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Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior (CAPES)
Apesar das in?meras vantagens advindas do uso da tecnologia de membranas filtrantes, algumas limita??es inerentes ao processo de incrusta??o tornam-se relevantes para sua aplicabilidade. O controle das condi??es operacionais consiste em importante ferramenta para mitigar o fouling e alcan?ar bons n?veis de efici?ncia. Nesse sentido, o objetivo deste trabalho foi investigar o efeito da press?o transmembrana e da vaz?o de concentrado no desempenho da ultrafiltra??o, aplicada ao p?s-tratamento de esgoto sanit?rio. O processo foi avaliado e otimizado variando-se a press?o (0,5 e 1,5 bar) e a vaz?o de concentrado (300 e 600 L/h), por meio de um planejamento fatorial 22, a fim de investigar os efeitos no fluxo permeado e na qualidade dos efluentes gerados, em cada condi??o operacional. Avaliaram-se os seguintes indicadores de qualidade para os permeados: pH, Condutividade El?trica, S?lidos Suspensos Totais, Turbidez, C?lcio e Demanda Qu?mica de Oxig?nio (DQO). Em todos os ensaios, observou-se diminui??o acentuada do fluxo permeado nos instantes iniciais, seguida de uma queda lenta que se prolongou at? atingir um patamar relativamente constante por volta dos 120 minutos de filtra??o. O aumento da press?o resultou em maior fluxo permeado inicial, por?m a queda do fluxo com o tempo foi maior para os ensaios realizados a press?o mais elevada, evidenciando um processo de incrusta??o mais pronunciado. Por outro lado, o aumento da vaz?o de concentrado resultou em queda mais lenta de fluxo permeado com o tempo de filtra??o. Com rela??o a qualidade dos permeados, a press?o transmembrana de 0,5 bar foi a que permitiu melhores resultados, sendo confirmado estatisticamente, por meio do teste da ANOVA two-way com medidas repetidas, efeito significativo da press?o sobre a turbidez do permeado. A vaz?o de concentrado, por sua vez, n?o apresentou influ?ncia significativa sobre nenhum dos par?metros de qualidade. Dessa forma, considerando que o efeito do aumento da vaz?o de concentrado no retardamento do fouling n?o resultou em melhoria significativa do fluxo permeado, conclui-se que a condi??o operacional otimizada para a gera??o de permeados com maior grau de pureza, associado a gera??o de um menor volume de res?duo, consiste naquela em que se aplica uma press?o transmembrana baixa associada a uma vaz?o menor de concentrado.
Despite the numerous advantages resulting from the use of membrane filters technology, intrinsic limitations fouling process become relevant to its applicability. The control of operating conditions is an important tool to mitigate fouling and achieve good levels of efficiency. In this sense, the objective of this study was to investigate the effect of transmembrane pressure and concentrate flow in the performance of ultrafiltration, applied to the post-treatment of domestic sewage. The process was evaluated and optimized by varying the pressure (0.5 and 1.5 bar) and the concentrate flow (300 and 600 L/h), using a 22 factorial design, in order to investigate the effects on the permeate flow and quality of effluents generated at each operating condition. We evaluated the following quality indicators for permeate: pH, electrical conductivity, total suspended solids, turbidity, calcium and Chemical Oxygen Demand (COD). In all tests, we observed marked reduction in the permeate flux at the early stages, followed by a slow decline that lasted until it reaches a relatively constant level, around 120 minutes of filtration. The increased pressure resulted in a higher initial permeate flux, but the decrease of the flow with time is greater for tests at higher pressure, indicating a more pronounced fouling process. On the other hand, increasing the concentrate flow resulted in a slower decline in permeate flux with the filtration time. Regarding the quality of permeate, the transmembrane pressure of 0,5 bar was the one that allowed better results, and was statistically confirmed through the two-way ANOVA test with repeated measures, significant effect of pressure on the turbidity of the permeate. The concentrate flow, in turn, showed no significant influence on any of the quality parameters. Thus, we conclude that, from an economic and environmental point of view, it is more interesting to operate ultrafiltration membrane system with a lower concentrate flow associated with a low transmembrane pressure, since under these conditions will produce less waste, and the permeate will present lower concentrations of the analyzed constituent, especially lower turbidity.
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Teh, Wen Chean. "Ramsey Algebras and Ramsey Spaces." The Ohio State University, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=osu1357244115.
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SOUZA, Renata Silva Cabral de. "Avalia??o do potencial antioxidante e antimicrobiano de prote?nas do soro de leite concentradas por membranas e hidrolisadas por diferentes enzimas comerciais." Universidade Federal Rural do Rio de Janeiro, 2013. https://tede.ufrrj.br/jspui/handle/jspui/2534.
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CAPES
The aim of this study was to evaluate the process of protein concentration in bovine whey proteins by ultrafiltration process and subsequently the protein hydrolysate obtained by enzymatic hydrolysis to produce bioactive peptides with potential antimicrobial and antioxidant activities. For concentration process was used a ceramic ultrafiltration membrane with a molecular range cut-off of 10-20 kDa, transmembrane pressure of 5 bar and, temperature of 30 ?C, 40 ?C and 50 ?C . The optimum temperature condition was at 40 ?C. The Volume Concentrate Factor (VCF) parameter was used as a end-point of the ultrafiltration process and fixed at 2, corresponding on concentrating the initial volume twice, in volume. At the temperature of 40 ?C, VCF had a correspondence on final protein concentration on the concentrated fraction by ultrafiltration and confirmed by Bradford method. Two commercial enzymes were tested Alcalase, Flavourzyme and an equivalent mixture of both 50:50 (w/w) in the hydrolysis reaction. The hydrolysis conditions were determined according to manufacturer instructions and confirmed by other studies: 60 ?C and pH 8 for Alcalase; 50 ?C and pH 7 for Flavourzyme; 50 ?C and pH 8 for enzyme mixture with enzyme / substrate ratio (w / w) 5/100 for all enzymes. The reaction was monitored by pH Stat method. The final Degree of Hydrolysis (DH) achieved was 15%, 52% and 63% for Flavourzyme, Alcalase and enzyme mixture, respectively. Five aliquots were collected along the hydrolysis for each enzyme reaction corresponding to differents DH in order to evaluatethe antioxidant activity by ORAC and ABTS assays with final values between 597- 1092 m? TE (ABTS) and from 1615 to 2920 ?M TE (ORAC) for Flavourzyme; 998-6290 ?M TE (ABTS) and 3092-7567 ?M TE ( ORAC) for Alcalase and finally 913-2678 ?M TE (ABTS) and 2547-5903 ?M TE (ORAC) for the enzyme mixture. The samples from all hydrolysates showed no antimicrobial activity against strains of Salmonella choleraesuis subsp. Enteritidis (ATCC 13076) and Listeria monocytogenes (ATCC 9117).
A proposta do presente trabalho foi avaliar a concentra??o das prote?nas do soro de leite bovino por ultrafiltra??o e posterior obten??o de hidrolisados proteicos deste concentrado via hidr?lise enzim?tica visando obter pept?deos bioativos com potencial atividade antimicrobiana e antioxidante. Para concentra??o das prote?nas do soro foi utilizada membrana cer?mica de ultrafiltra??o com massa molar de corte de 10-20 kDa, press?o aplicada ? membrana de 5 bar, temperaturas testadas (30 ?C, 40 ?C e 50 ?C) . A temperatura ?tima selecionada foi de 40 ?C. O Fator de Concentra??o Volum?trica foi o par?metro utilizado para indicar o final do processo de ultrafiltra??o sendo fixado em duas vezes o volume inicial da alimenta??o. Na temperatura de 40 ?C foi obtida correspond?ncia entre a concentra??o volum?trica e a concentra??o proteica final na fra??o retida pela UF, que tamb?m foi o dobro da encontrada na fra??o alimenta??o, avaliada pelo m?todo de Bradford. Foram testadas duas enzimas comerciais: Alcalase, Flavourzyme e uma mistura equivalente de ambas, na propor??o 50:50 (m/m) na rea??o de hidr?lise. As condi??es de rea??o enzim?tica foram determinadas de acordo com instru??es do fabricante e corroboradas por outros estudos em: 60 ?C, pH 8 para Alcalase; 50 ?C, pH 7 para Flavourzyme; 50 ?C, pH 8 para mistura enzim?tica e rela??o enzima/substrato (g/g) foi de 5/100 para todas as enzimas. A rea??o de hidr?lise foi monitorada pelo m?todo pH Stat. Os Graus de Hidr?lise (GH) finais alcan?ados foram de 15 %, 52 % e 63 % para Flavourzyme, mistura enzim?tica e Alcalase, respectivamente. Foram coletadas cinco al?quotas correspondentes a diferentes GH ao longo da rea??o para cada condi??o enzim?tica utilizada e avaliadas quanto a atividade antioxidante pelos m?todos ABTS e ORAC tendo valores entre 597 a 1092 ?M TE (ABTS) e 1615 a 2920 ?M TE (ORAC) para Flavourzyme, 998 a 6290 ?M TE (ABTS) e 3092 a 7567 ?M TE (ORAC) para Alcalase e por fim, 913 a 2678 ?M TE (ABTS) e 2547 a 5903 ?M TE (ORAC) para a mistura enzim?tica. Nenhuma das amostras de hidrolisado com diferentes GH apresentou atividade antimicrobiana contra cepas de Salmonella choleraesuis subsp. Enteritidis (ATCC 13076) e Listeria monocytogenes (ATCC 9117).
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Nygren, Astrid, and Robin Slättengren. "Analys och jämförelse av två pilotanläggningar med olika sammansättning av membran : Vid rening av processvatten från industri." Thesis, Linnéuniversitetet, Institutionen för byggd miljö och energiteknik (BET), 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:lnu:diva-65693.
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Vattentillgången på Öland har under en lång tid varit mycket ansträngd och har kommit till en punkt då det inte längre är hållbart. För att nå en mer långsiktig lösning planerar Mörbylånga kommun med hjälp av Norconsult att bygga ett vattenreningsverk. Detta kommer att rena bräckt vatten ifrån Kalmarsund samt processvatten ifrån Guldfågeln AB, som tillsammans kommer att fungera som ett komplement till det redan befintliga sötvattnet. Två pilotanläggningar som renar processvatten ifrån en industri, genom ultrafilter kombinerat med omvänd osmos, har utvärderats. En metod för att sammanställa de kostsamma driftparametrarna elförbrukning, förbrukning av kemikalier samt underhållsarbete vid drift och membranens inköpskostnad genom en LCC har tagits fram. Denna metod ger en ungefärlig totalkostnad per kubikmeter av det renade vattnet. Även vattenkvaliteten på ingående råvatten, vattnet mellan membranen samt det utgående vattnet har analyserats. Detta för att undersöka att processerna fungerar som den ska, samt ge en indikation på vilka mineraler som kommer att behöva tillsättas i efterhand. Pilot B blir ca fem kronor dyrare per kubikmeter jämfört med Pilot A. De totala kostnaderna, 9.70 – 10.79 kr/m3 för Pilot A och 15.19 – 15.28 kr/m3 för Pilot B, kan jämföras med den nuvarande kostnaden för en kubikmeter vatten i Mörbylånga, 15 kr/m3, samt den kostnad kommunen betalade sommaren 2016 för att frakta vatten i tankbilar, 70 kr/m3.
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Santos, Alex da Silva. "Produ??o, concentra??o e caracteriza??o parcial de extrato celulol?tico produzido por linhagem f?ngica mutante." Universidade Federal Rural do Rio de Janeiro, 2011. https://tede.ufrrj.br/jspui/handle/jspui/1152.
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Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior, CAPES
The production of enzymes for application at different areas of food agroindustry presents promising future perspectives, due to several intrinsic properties regarded to the performance of the enzymes as natural and biodegradable compounds, responsible for achieving specific reactions with better quality. Cellulases have been the most employed enzymes on food industry, acting sinergically on the hydrolysis of the glucosidic links ?-1,4 from the molecules of cellulose, and being used on several applications in this sector as in vegetal oils extraction, fruit maceration and juice clarification. Based on this context, the present study aimed to produce, concentrate and partially characterize an enzymatic extract by a mutant fungus strain of Aspergillus niger. Production was performed by solid-state fermentation (SSF) in aerated columns, using humidified wheat bran with (NH4)2SO4 solution on 0,1N HCl as substrate and cellobiose as inducer. Cellulolytic extract was a blend of extracts from three different assays selected on previous studies as the best conditions for the enzymes caboxymethilcellulase, ?-glucosidase and filter paper cellulose (FPase). During the characterization of the enzymatic extract, besides cellulases activity, the presence of protease and other enzymes with similar action to cellulases as xylanase and poligalacturonase was evaluated. For enzymatic extract concentration, three different strategies were performed: ultrafiltration, using a stainless steel plates system through a 20 kDa molecular weight cut-off polyethersulphone membrane and 0,014 m2 area; precipitation with ammonium sulphate under 20%, 40 %, 60% and 80% saturation level and lyophiilization. The best results were achieved by the ultrafiltration process, partially purified sample and providing enzymatic activities recovery between 75% and 99%, except for FPase. SDS-PAGE analysis presented 15 visible protein bands on cellulolytic extract with molecular weights ranging from 13.3 to 104.6 kDa. Zymography test was applied for cellulases and correlate enzymes as well as to protease, however, just for the last one the conditions were considered appropriate, identifying bands on 88, 103 and 145 kDa. The effective performance of ?-glucosidase and xylanase over xylan and cellobiose hydrolysis was confirmed by thin layer chromatography. A central rotational statistical design 22 with 4 central points was used for evaluating optimal temperature and pH for carboxymethylcellulase and ?-glucosidase. The analysis of the results obtained for both enzymes demonstrated that all variables were significative at a 95% confidence level. Based on the conditions studied it can be concluded that optimal pH and temperature ranges for efficient and combined action of carboxymethylcellulase and ?-glucosidase are 3.7 to 5.5 and 60 to 65?C, respectively.
A produ??o de enzimas para uso em diferentes ?reas da agroind?stria de alimentos mostra perspectivas futuras promissoras, devido ?s v?rias caracter?sticas inerentes ? a??o das enzimas que s?o compostos naturais, biodegrad?veis e capazes de desempenhar rea??es espec?ficas com melhor qualidade. Entre as enzimas mais utilizadas pelo setor de alimentos est?o as celulases, um complexo de enzimas que atuam de forma sin?rgica sobre a hidr?lise das liga??es glicos?dicas ?-1,4 das mol?culas de celulose, e possuem v?rias aplica??es industriais neste setor, como na extra??o de ?leos vegetais, na macera??o de frutas e na clarifica??o de sucos. Dentro deste contexto, este trabalho teve como objetivo produzir, concentrar e caracterizar parcialmente um extrato celulol?tico obtido por linhagem f?ngica mutante de Aspergillus niger. A produ??o foi realizada por fermenta??o no estado s?lido (FES) em colunas aeradas, utilizando como substrato farelo de trigo triturado umidificado com solu??o de (NH4)2SO4 em HCl 0,1N e celobiose, como indutor. O extrato celulol?tico consistiu de uma mistura de extratos obtidos em 3 ensaios fermentativos diferentes, selecionados em trabalhos anteriores como as melhores condi??es para produ??o de cada uma das enzimascarboximetilcelulase (CMCase), ?-glicosidase e celulase em papel de filtro (FPase). Durante a caracteriza??o do extrato enzim?tico, al?m da atividade das celulases, tamb?m era avaliado o teor de prote?na, a presen?a de protease e de enzimas correlatas ? a??o de celulases como xilanase e poligalacturonase. Para concentra??o do extrato enzim?tico foram realizadas tr?s diferentes estrat?gias: ultrafiltra??o em um sistema de quadro e placas em a?o inox, utilizando uma membrana de polietersulfona com massa molar de corte de 20 kDa e ?rea de 0,014m2; precipita??o com sulfato de am?nio utilizando satura??es de 20%, 40%, 50%, 60%, 80% e liofiliza??o. O processo de ultrafiltra??o foi o que obteve o melhor resultado, purificando parcialmente a amostra e proporcionando uma recupera??o das atividades enzim?ticas entre 75% e 99% para todas as atividades avaliadas, exceto FPase. A an?lise eletrofor?tica em SDS-PAGE demonstrou a presen?a de 15 bandas vis?veis de prote?nas no extrato celulol?tico com pesos moleculares que compreendem uma faixa entre 13,3 e 104,6 kD. O teste de zimografia foi realizado para as celulases e enzimas correlatas, bem como para protease, no entanto somente para esta ?ltima, as condi??es testadas foram adequadas tornando-se poss?vel identificar bandas em 88, 103 e 145 kDa. A efetiva a??o das enzimas ?-glicosidase e xilanase na hidr?lise de celobiose e xilana, respectivamente,foi comprovada em cromatografia de camada fina. Al?m disso, a temperatura e pH ?timos de atua??o de carboximetilcelulase e ?-glicosidase foram determinados utilizando o delineamento composto central rotacional 22, com 4 pontos centrais. A an?lise dos resultados de ambas as enzimas demonstrou que as vari?veis eram significativas, a um n?vel de confian?a de 95%. Com base nas condi??es estudadas, concluiu-se que as faixas de pH e temperatura ?timos para a atua??o eficiente e conjunta de CMCase e ?-glicosidase est?o entre 3,7 a 5,5 e 60 a 65 ?C, respectivamente.
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Kebbab, Eric Franck Idir. "Aspects géométriques des principes locaux-globaux dans la théorie abstraite des formes quadratiques." Phd thesis, Université Pierre et Marie Curie - Paris VI, 2014. http://tel.archives-ouvertes.fr/tel-00990237.
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Les espaces d'ordres abstraits sont introduits par M. Marshall dans les années 70, dans la perspective d'offrir un cadre abstrait à l'étude des formes quadratiques. Vers le début des années 90, les travaux de M. Dickmann, L. de Lima et de F. Miraglia, ont donné naissance à la version duale des groupes spéciaux. Le premier thème que nous traiterons est la caractérisation des points d'un espace d'ordres du corps de fonctions d'une variété réelle, nous reprendrons un résultat de Brumfiel affirmant l'existence d'une correspondance entre ces ordres et des ultrafiltres de semi-algébriques. Nous appliquerons ceci au corps R(x,y). Suivra la caractérisation des ordres de ce corps à travers la notion de demi-branche de Bézout. Le second thème traite des principes locaux-globaux généralisés (ou Conjecture pp). Le premier résultat de la thèse porte sur la séparation des constructibles et sur la principalité des basiques. Nous montrerons que le langage des groupes spéciaux nous offre une vision claire du fait que ces principes découlent trivialement du principe de l'isotropie étendu. Le second résultat traite des contre-exemples à la conjecture dans le cas de la conique rationnelle donnée par l'équation x2+y2=3. Le dernier résultat (le plus important), aborde la conjecture pp dans le cadre du corps R(x,y). Nous nous intéresserons à des familles de polynômes vérifiant certaines conditions géométriques et montrerons que toute formule pp, ayant ses paramètres dans cette famille, vérifie un principe local-global. Nous les baptiserons formules V-universelles. Nous clorons le dernier chapitre par deux méthodes de construction.
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Bohne, Guido. "Ausgewählte Eigenschaften des Sporopollenins der Kiefer." Doctoral thesis, Humboldt-Universität zu Berlin, Mathematisch-Naturwissenschaftliche Fakultät I, 2007. http://dx.doi.org/10.18452/15590.
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Gegenstand der Arbeit sind Zusammenhänge zwischen physikochemischen Eigenschaften und Funktionen der Exine bei Ausbreitung, Bestäubung und Befruchtung. Dabei bewährte sich der Einsatz der 3-kammrigen Sporopolleninkapseln (Zentralkapsel und Sacci) in der Permeationschromatographie. Sowohl kinetisch bedingte chromatographische Dispersion kleiner Moleküle als auch Konzentrationsänderungen von Zuckern und Dextranmolekülen im Medium wurden zur Bestimmung von Permeabilitätskoeffizienten der Nexine genutzt. Die Wasserabsorptionskapazität von Exinefragmenten und die hydraulische Leitfähigkeit der Nexine wurden anhand von Konzentrationsänderungen ausgeschlossener Dextranmoleküle ermittelt. Das Tectum der saccalen Sexine ist eine Mikrofiltermembran mit scharfer Trenngrenze im Submikrometerbereich; daher werden an den Sacci nur Hydrokolloide mit Stokes''schen Radius über 100 nm (z.B. aus nativem Dextran) ausgeschlossen. Die Nexine ist eine nicht-ideale Umkehrosmose-Membran, die in Zucker- und Salzlösungen hohe Reflexionskoeffizienten zeigt; zusätzlich besitzt sie wenige große Poren, die den Austausch von Zuckern und selbst kleinen Polymermolekülen ermöglichen. Die hydraulische Leitfähigkeit der Nexine liegt im Größenbereich derjenigen von Plasmamembranen (0,39-0,48 µm s-1 MPa-1); die Ergebnisse zeigen, dass die Exine weder die Nährstoffaufnahme des Sporoplasten aus der lokulären Flüssigkeit noch dessen rasche Rehydratation in der Mikropyle behindert. Die Einfaltungen der distalen Nexine (oberhalb der Sacci) und die Omega-Faltung der Exine zwischen den Sacci (Leptom) bieten beim Quellvorgang Schutz vor zu schneller Flächenausdehnung der Plasmamembran. Der Corpus kann mit konzentrierten Elektrolytlösungen beladen werden. Beim anschließenden osmotischen Schwellen in Wasser reißt die Exine, und der Sporoplast wird mit anhaftender Intine ausgeschleudert. Wasser und andere polare Flüssigkeiten adhärieren stärker als hydrophobe Flüssigkeiten an Sporopollenin. Die Sporopolleninmatrix weist eine hohe Feststoffdichte auf, ist wenig quellfähig (0,18 mL g-1 TM) und deformationsstabil. Dies ermöglicht die Pulverbildung beim Trocknen.Subject of this thesis are relationships between physicochemical properties and functions of the exine concerning propagation, pollination and fecundation. Here the application of the 3-chambered sporopollenin-microcapsules (central capsule and sacci) in permeation chromatography proved of value. Both the kinetically dependent dispersion of small molecules and changes in concentration of sugars and dextran molecules in the medium were analysed to determine permeability coefficients of the nexine. The water absorption capacity of exine fragments and the hydraulic conductance of the nexine were calculated by means of changes in concentrations of excluded dextran molecules. The tectum of the saccal sexine is a microfiltration membrane with a sharp cut off in the submicrometer range; thus hydrocolloids with Stokes´radii over 100 nm (e.g. from native dextran) are excluded from the sacci. The nexine is a non-ideal reverse osmosis membrane having high reflexion coefficients in sugar and salt solutions; in addition few large pores allow the exchange of sugars and even of small polymers. The hydraulic conductance of the nexine is in the range typically for plasmamembranes (0.39-0.48 µm s-1 MPa-1); the results indicate that the exine does neither obstruct the uptake of nutrients by the sporoplast from the locular fluid nor hinder the rapid rehydration in the micropyle. When rehydrating, the distal foldings of the nexine (above the sacci) and the omega-like folding of the exine between the sacci (leptom), provide protection for the plasmamembrane when its surface area has to increase too rapidly. The corpus can be loaded with a concentrated electrolyte solution. When subsequently transferred into water the exine rupture and the sporoplast along with the intact intine is ejected. Water and other polar liquids adhere stronger to sporopollenin than hydrophobic ones. The matrix of sporopollenin show a high density in its solid content, water absorption capacity is low (0.18 mL g-1 DM) and it is resistant to deformation. This enable the formation of powder while dehydrating.
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Dintoe, Isia T. "Ultrafilters and semigroup algebras." Thesis, 2016. http://hdl.handle.net/10539/19359.
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School of Mathematics
University of the Witwatersrand (Wits), Johannesburg
31 August 2015
Submitted in partial fulflment of a Masters degree at WitsThe operation defined on a discrete semigroup S can be extended to the Stone- Cech compactification S of S so that for all a 2 S, the left translation S 3 x 7! ax 2 S is continuous, and for all q 2 S, the right translation S 3 x 7! xq 2 S is continuous. Because any compact right topological semigroup, S contains a smallest two-sided ideal K( S) which is a completely simple semigroup. We give an exposition of some basic results related to the semigroup S and to the semigroup algebra `1( S). In particular, we review the result that `1( N) is semisimple if and only if `1(K( N)) is semisimple. We also review the reduction of the question whether `1(K( N)) is semisimple to a question about K( N).
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Baker, Joni. "Some topological results on ultrafilters." 2001. http://www.library.wisc.edu/databases/connect/dissertations.html.
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Benedikt, Michael A. "Nonstandard analysis and special ultrafilters." 1993. http://catalog.hathitrust.org/api/volumes/oclc/31251243.html.
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Thesis (Ph. D.)--University of Wisconsin--Madison, 1993.Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 141-143).
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Zirnstein, Heinrich-Gregor. "Formulating Szemerédi's theorem in terms of ultrafilters." 2012. https://ul.qucosa.de/id/qucosa%3A16816.
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Van der Waerden's theorem asserts that if you color the natural numbers with, say, five different colors, then you can always find arbitrarily long sequences of numbers that have the same color and that form an arithmetic progression. Szemerédi's theorem generalizes this statement and asserts that every subset of natural numbers with positive density contains arithmetic progressions of arbitrary length.
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Bartosova, Dana. "Topological Dynamics of Automorphism Groups of omega-homogeneous Structures via Near Ultrafilters." Thesis, 2013. http://hdl.handle.net/1807/43472.
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In this thesis, we present a new viewpoint of the universal minimal flow in the language of near ultrafilters. We apply this viewpoint to generalize results of Kechris, Pestov and Todorcevic about a connection between groups of automorphisms of structures and structural Ramsey theory from countable to uncountable structures. This allows us to provide new examples of explicit descriptions of universal minimal flows as well as of extremely amenable groups.
We identify new classes of finite structures satisfying the Ramsey property and apply the result to the computation of the universal minimal flow of the group of automorphisms of $\P(\omega_1)/\fin$ as well as of certain closed subgroups of groups of homeomorphisms of Cantor cubes. We furthermore apply our theory to groups of isometries of metric spaces and the problem of unique amenability of topological groups.
The theory combines tools from set theory, model theory, Ramsey theory, topological dynamics and ergodic theory, and homogeneous structures.
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Verner, Jonathan. "Ultrfiltry a nezávislé sytémy." Doctoral thesis, 2011. http://www.nusl.cz/ntk/nusl-311369.
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This work presents an overview of several different methods for construct- ing ultrafilters. The first part contains constructions not needing additional assumptions beyond the usual axioms of Set Theory. K. Kunen's method using independent systems for constructing weak P-points is presented. This is followed by a presentation of its application in topology (the proof of the existence of sixteen topological types due to J. van Mill). Finally a new con- struction due to the author is presented together with a proof of his result, the existence of a seventeenth topological type: ω∗ contains a point which is discretely untouchable, is a limit point of a countable set and the countable sets having it as its limit point form a filter. The second part looks at constructions which use additional combina- torial axioms and/or forcing. J. Ketonen's construction of a P-point and A. R. D. Mathias's construction of a Q-point are presented in the first two sections. The next sections concentrate on strong P-points introduced by C. Laflamme. The first of these contains a proof of a new characterization theorem due jointly to the author, A. Blass and M. Hrušák: An ultrafilter is Canjar if and only if it is a strong P-point. A new proof of Canjar's the- orem on the existence of non-dominating filters (Canjar filters) which uses...
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Shuungula, Onesmus. "Ultrafilter semigroups." Thesis, 2011. http://hdl.handle.net/10539/10146.
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(1) Given a local left topological group X with a distinguished element 0,
denote by Ult(X) the subsemigroup of X consisting of all nonprinci-
pal ultra lters on X converging to 0. Any two countable nondiscrete
zero-dimensional local left topological groups X and Y with count-
able bases are locally isomorphic and, consequently, the subsemigroups
Ult(X) X and Ult(Y ) Y are isomorphic. However, not every
two homeomorphic zero-dimensional local left topological groups are
locally isomorphic. In the rst result of this thesis it is shown that for
any two homeomorphic direct sums X and Y , the semigroups Ult(X)
and Ult(Y ) are isomorphic.
(2) Let S be a discrete semigroup, let S be the Stone- Cech compacti-
cation of S, and let T be a closed subsemigroup of S. The second
and main result of this thesis consists of characterizing ultra lters from
the smallest ideal K(T) of T and from its closure c` K(T), and show-
ing that for a large class of closed subsemigroups T of S, c` K(T)
is not an ideal. This class includes the subsemigroups 0+ Rd and
H (
L
Z2).
v
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Hýlová, Lenka. "Aplikace teorie ultrafiltrů." Master's thesis, 2021. http://www.nusl.cz/ntk/nusl-448357.
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This thesis studies ultrafilters and their various applications in topology, social choice theory and construction of a nonstandard universe. First of all, we introduce basic properties of ultrafilters and show how to use them to construct nonstandard framework. Next, we prove Arrow's impossibility theorem which states that every electoral system with a finite set of voters satisfying certain natural conditions necessarily admits at least one dictator who determines the society's preferences. However, if the set of voters is infinite, this is not true anymore and ultrafilters play a key role in the proof. We present two counterexamples in the infinite case using nonstandard framework. A similar theorem holds in the case where the preferences are real functions. Again, we show two examples of electoral systems that are not dictatorial - one using Banach limits and the other using hyperfinite sums. Finally, we use the ultrafilters to construct the Čech-Stone compactification of natural numbers. We show that the nonstandard enlargement of natural numbers equipped with suitable topology is the Čech-Stone compactification of the set of natural numbers. 1
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Verner, Jonathan. "Topologicky různé ultrafiltry." Master's thesis, 2007. http://www.nusl.cz/ntk/nusl-279006.
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Flašková, Jana. "Ultrafiltry a malé série." Doctoral thesis, 2006. http://www.nusl.cz/ntk/nusl-266015.
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Kornacki, Jeffrey L. "Thermal inactivation of bacteria in ultrafiltered milk retentates." 1986. http://catalog.hathitrust.org/api/volumes/oclc/15554539.html.
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Starý, Jan. "Úplné Booleovy algebry a extremálně nesouvislé prostory." Doctoral thesis, 2014. http://www.nusl.cz/ntk/nusl-326197.
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We study the existence of special points in extremally disconnected compact topological spaces that witness their nonhomogeneity. Via Stone duality, we are looking for ultrafilters on complete Boolean algebras with special combinatorial properties. We introduce the notion of a coherent ultrafilter (coherent P-point, coherently selective). We show that generic existence of such ultrafilters on every complete ccc Boolean algebra of weight not exceeding the continuum is consistent with set theory, and that they witness the nonhomogeneity of the corresponding Stone spaces. We study the properties of the order-sequential property on σ-complete Boolean algebras and its relation to measure-theoretic properties. We ask whether the order-sequential topology can be compact in a nontrivial case, and partially answer the question in a special case of the Suslin algebra associated with a Suslin tree.
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Lin, Chia-Chun, and 林家駿. "Effect of Ring Distance on the Performance in Ring-Rod Tubular-Membrane Ultrafilter." Thesis, 2004. http://ndltd.ncl.edu.tw/handle/15638409724041719383.
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碩士淡江大學
化學工程與材料工程學系碩士班
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The effect of operating conditions on the permeate flux in a ringed-rod tubular ultrafilter has been investigated. Creating turbulent flow in the tubular membrane module by inserting concentrically a steel rod wrapped with several wire rings has two conflict effect. One, the decrease in resistance to permeation due to reduction in concentration polarization, is good for ultrafiltration, while the other, the decrease in average transmembrane pressure due to increase in friction pressure loss, is bad for ultrafiltration. Experiments for the ultrafiltration of Dextran T500 aqueous solution were carried out. Considerable enhancement of performance was achieved by gradually changing the ring distance of fixed ring number, instead of uniform distance. This is because that along the flow channel, the thickness of the concentration polarization layer increases while the transmembrane pressure decreases.
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Pichaicharnarong, Sirima. "Effects of Penicillium roqueforti strains on blue cheese made from ultrafiltered milk." 1990. http://catalog.hathitrust.org/api/volumes/oclc/23022382.html.
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Takman, Maria. "Utvärdering av nano- och ultrafilter för avskiljning av cyanotoxiner i dricksvatten : Effekter av membrantyp och råvattenkvalitet." Thesis, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-293638.
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The drinking water production in Sweden is facing challenges because of climatic changes, eutrophication and brownification, which contributes to an increase of algal blooms. This can lead to a production of different types of toxins, and the most common group of algal toxins is the hepatotoxic microcystins (MC). Other algal toxins that occur in Sweden are anatoxin-A (ATX-A) and the paralytic shellfish toxins (PST), which are neurotoxic. Flocculation and filtration has been shown to reduce intracellular MC, but to reduce extracellular MC it seems like other techniques are needed, such as membrane filtration, active carbon or ozone. It has also been shown that dissolved organic carbon (DOC) might affect the reduction of MC, either through occupying adsorption spots on the membrane, or through bindings between MC and DOC. In this project, the reduction of four types of added MC (microcystin-LR, microcystin-RR, microcystin-LY and (D-Asp3)microcystin-LR) with two nanofilters (NF) (with molecular weight cutoff (MWCO) 300-500 Da and 1000 Da) and one ultrafilter (UF) (MWCO 10000 Da) was studied. Further, the sorption between toxins and membrane or between toxins and DOC was studied. Water samples from three Swedish lakes were used to achieve a varying DOC-character. The reduction was also studied in synthetic water (MilliQ-water with adjusted pH and conductivity). This was done in order to study if the reduction was affected of the presence of DOC. The reduction of ATX-A and PST was studied in one experiment, with an NF-membrane (MWCO 1000 Da). The studied PST’s were saxitoxin (STX), N-sulfocarbamoyl-gonyautoxin-2 (C1) and Gonyuatoxin‑2 (GTX2). MC was reduced to under the limit of detection for all NF-experiments, while a low or no reduction was observed with UF. MC-RR was the toxin that, to the biggest extent, bound to the membrane or to DOC. MC seemed to bind to the membrane or to DOC to a higher extent when the DOC was hydrophilic and low molecular autochthonous, as compared to when the DOC was allochthonous. The reduction of ATX-A and PST was 20 – 40 %, with a reduction that declined during the experiment. C1, the PST with highest molecular weight and lowest net charge, was reduced to the lowest extent, while STX, the PST with the lowest molecular weight and the greatest net charge, was reduced to the highest extent. This implies that size exclusion was not a contributing reduction mechanism for ATX-A or PST, while electrostatic mechanisms probably were more important.