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Статті в журналах з теми "Foundry form, forming mixture"
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Dan, Olena, and Larysa Trofimova. "A Study of The Properties of Forming Mixtures Containing Polystyrene Wastes." Journal of Casting & Materials Engineering 5, no. 2 (June 9, 2021): 14–19. http://dx.doi.org/10.7494/jcme.2021.5.2.14.
Повний текст джерелаАнотація:
Expanded polystyrene is widely used as a material for packaging, in modern construction as a heat and sound insulation layer, in thermal insulation systems for buildings, as well as tanks and pipelines. It is additionally used in foundry engineering for the production of models which are gasified during the production of castings from ferrous and non-ferrous alloys under the contact with liquid metal. The use of expanded polystyrene products is associated with waste generation, both in production and in consumption. About 40–50 kg/person of polystyrene waste is generated per year. The peculiarity of polymeric wastes is their resistance to aggressive environments. They do not rot and the destruction processes in natural conditions proceed rather slowly, with the formation of harmful substances that poison the environment. Therefore, the problem of the processing of waste from polymeric materials is of great importance, not only from the standpoint of environmental protection, but also due to the fact that in conditions of a shortage of polymer raw materials, this waste becomes a powerful raw material resource. This article describes the prospects for recycling expanded polystyrene wastes in foundry engineering. In this work, the properties of molding and core sands containing a combined binder, consisting of a solution of expanded polystyrene wastes in turpentine and clay were investigated, and their main characteristics (weight during stretching and crumbling) were determined. Molding and core mixtures, which contain only a binder in the form of a solution of expanded polystyrene in turpentine, have a crude strength of not more than 0.01 MPa. The introduction of a mixture of clay in the amount of 2–3% allows a crude strength of the mixture of up to 0.05 MPa to be obtained. After drying, the investigated mixtures containing a solution of expanded polystyrene wastes and clay have a tensile strength of up to 2.1 MPa. Mixtures into which a solution of polystyrene wastes and clay was introduced have an insignificant gas capacity and satisfactory gas permeability.
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Bartkowski, Dariusz, Aneta Bartkowska, Paweł Popielarski, Jakub Hajkowski, and Adam Piasecki. "Characterization of W–Cr Metal Matrix Composite Coatings Reinforced with WC Particles Produced on Low-Carbon Steel Using Laser Processing of Precoat." Materials 13, no. 22 (November 21, 2020): 5272. http://dx.doi.org/10.3390/ma13225272.
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The paper presents the study results of laser processing of precoat applied on C30 steel. The precoat consisted of powder mixtures with a binder in the form of water glass. Tungsten powder, chromium, and tungsten carbide (WC) were used to produce the precoat. The laser processing was carried out using a Yb:YAG disc laser with a rated power of 1 kW. Constant producing parameters (power of laser beam, 600 W; laser beam scanning rate, 400 mm/min) were applied. Chemical composition of the precoat was a variable parameter in coating production. A mixture consisting of 50% W and 50% Cr as a metal matrix was prepared. Subsequently, WC particles in weight ratios of 25%, 50%, and 75% were added to matrix. As a result, W–Cr metal matrix composite coatings reinforced with WC particles were formed. This study focused on investigation of microstructure, microhardness, phase, and chemical composition as well as corrosion and wear resistance, of the newly formed W–Cr/WC coatings. An instrumented nanoindentation test was also used in this study. As a result of laser beam action, the newly formed coatings had an interesting microstructure and good properties which were improved in comparison to substrate material. It is anticipated that the resulting coatings, depending on the treatment parameters (e.g., W–Cr/WC powder mixture) used, can be successfully applied to metal forming or foundry tools.
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Vdovin, K. N., A. A. Zaitseva, and N. A. Feoktistov. "Research of Properties and Structure of Boron-modified Roll-foundry Iron." Journal of Materials Science Research 5, no. 2 (February 23, 2016): 82. http://dx.doi.org/10.5539/jmsr.v5n2p82.
Повний текст джерелаАнотація:
<p class="1Body">The aim of the research is to determine the properties and the structure of boron-alloyed iron used for rolls production. It was found that boron can form different carbides in iron, which significantly improve both hardenability and microhardness. Iron borides Fe<sub>3</sub>(B,C) are also formed in cast iron as only 40% of carbon atoms in cementite matrix can be replaced by boron. Besides, boron influences the temperatures of structural constituents decomposition (increases the rate of cementite decomposition), it also decreases the temperatures of developing phase transformations. The research group determined the kinetics of martensite decomposition, which is formed when chilled cast iron is poured into a metal mold and then undergoes thermal treatment to the temperature of 400 °C. In the temperature range of 210 – 400 °C the main process is decomposition of the retained austenite into bainite, while in the temperature range of 400 – 500 °C, the main process is decomposition of martensite and forming a ferrite-cementite mixture. In order to get the necessary properties of the roll face, it is necessary to provide its thermal treatment (tempering), when it is heated to the temperature of 400 °C to avoid martensite decomposition, because otherwise in the process of roll operation it can result in crack formation. </p>
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Vdovin, K. N., A. A. Zaitseva, and N. A. Feoktistov. "Research of Properties and Structure of Boron-modified Roll-foundry Iron." Journal of Materials Science Research 5, no. 2 (February 23, 2016): 88. http://dx.doi.org/10.5539/jmsr.v5n2p88.
Повний текст джерелаАнотація:
<p class="1Body">The aim of the research is to determine the properties and the structure of boron-alloyed iron used for rolls production. It was found that boron can form different carbides in iron, which significantly improve both hardenability and microhardness. Iron borides Fe<sub>3</sub>(B,C) are also formed in cast iron as only 40% of carbon atoms in cementite matrix can be replaced by boron. Besides, boron influences the temperatures of structural constituents decomposition (increases the rate of cementite decomposition), it also decreases the temperatures of developing phase transformations. The research group determined the kinetics of martensite decomposition, which is formed when chilled cast iron is poured into a metal mold and then undergoes thermal treatment to the temperature of 400 °C. In the temperature range of 210 – 400 °C the main process is decomposition of the retained austenite into bainite, while in the temperature range of 400 – 500 °C, the main process is decomposition of martensite and forming a ferrite-cementite mixture. In order to get the necessary properties of the roll face, it is necessary to provide its thermal treatment (tempering), when it is heated to the temperature of 400 °C to avoid martensite decomposition, because otherwise in the process of roll operation it can result in crack formation. </p>
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Soddell, Jacques A., Robert J. Seviour, Linda L. Blackall, and Phil Hugenholtz. "New foam-forming nocardioforms found in activated sludge." Water Science and Technology 37, no. 4-5 (February 1, 1998): 495–502. http://dx.doi.org/10.2166/wst.1998.0704.
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In a numerical taxonomic survey of foam-forming actinomycetes, representatives of four groups were selected for further taxonomic study because they either did not cluster with known reference strains of nocardioforms or their relationship to them was uncertain. Phylogenetic studies, using 16S rDNA sequencing, showed that one group probably represented a previously described species, Rhodococcus erythropolis, but two possibly represented new species of Gordona and Rhodococcus. The fourth group represented an independent line of descent, possibly a new genus. These, together with strains of foam-formers Gordona amarae and Skermania piniformis, were evaluated for their growth on hydrophobic substrates likely to be found in activated sludge plants. All grew well on vegetable oils (olive, safflower and coconut) and on mixtures of hydrocarbons like paraffin oil, but at varying rates. However, growth on kerosene and hexadecane was less consistent. One feature of growth on the hydrophobic substrates was the attachment of most cells to the hydrophobic substrate rather than growth in the aqueous phase. This suggests a possible method for competing for nutrients with faster-growing (but not hydrophobic) organisms in activated sludge.
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Dotsenko, Vadim, Viktoria Boichuk, Vadym Fedorenko, and Yevhenii Tsybulskyi. "OBTAINING OF LOCALLY OPTIMAL SOLUTIONS BY COMBINING PROPERTIES OF MIXTURES FOR FOUNDRY MANUFACTURE." EUREKA: Physics and Engineering 6 (November 30, 2018): 48–53. http://dx.doi.org/10.21303/2461-4262.2018.00795.
Повний текст джерелаАнотація:
The aim of research is establishment of the relationship between the various properties of the mixture with liquid glass and hardener for the foundry industry – survivability, compressive strength and crumbling. Such an interrelation in the form of an adequate functional dependence makes it possible to assess the quality of the mixture for its compliance with the specified requirements, without resorting to additional laboratory measurements. It is very important to evaluate its suitability for the manufacture of rods, in particular, to meet the stringent requirements of production. Using the combined procedure of active and passive experiments, a regression equation was obtained describing the dependence of the mixture survivability on compressive strength and crumbling. It has been established that compressive strength is a more significant factor influencing survivability compared to crumbling, and it is almost 3 times (а1=0.36>а2=0.13). Analysis of the resulting regression equation shows that both of these factors have a positive effect on the survivability of the mixture – with an increase in compressive strength and crumbling, the survivability increases. In part, this conclusion requires confirmation in relation to crumbling, since the fact of a positive effect on survivability may be in doubt. By applying the procedure of comb analysis to the obtained regression equation, in order to describe the response surface, locally optimal solutions are established in the form of a ridge line. This line represents the optimal combination of compressive strength and shedding in the sense of ensuring the maximum survivability of the mixture. The corresponding ratios can be used as a nomogram, which allows to evaluate the ratios of the desired properties of the mixture, if it is fundamentally important to assess its quality by a set of properties.
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Liu, Tao, Quan Bo Tang, and Jian Hua Zhao. "The Tendency of Oxide Inclusion on Magnesium Alloys Intake Manifold in Tilt Cast." Materials Science Forum 686 (June 2011): 367–70. http://dx.doi.org/10.4028/www.scientific.net/msf.686.367.
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The oxide inclusion formation tendency in tilting cast magnesium alloys intake manifold was studied by numerical simulation. Two different programs were used for results comparison. The results indicate that it was easier to form oxide inclusion when connecting foundry ladle with the junction panel of intake manifold instead of cavity resonator. The oxidation mixture is prone to appear at the ribs and outer wall of the four main air piles of the intake manifold. The formation of oxide inclusion would be influenced by the flowing state of the melt during casting process.
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H., Arjun, and Pinaki Chaudhuri. "Glass forming liquids in a quenched random potential." Soft Matter 16, no. 14 (2020): 3574–85. http://dx.doi.org/10.1039/c9sm01729a.
Повний текст джерелаАнотація:
A study of the emergence of glassy dynamics in a model two-dimensional colloidal binary mixture, via the interplay of the intrinsic density correlations with a quenched disorder in the form an externally imposed spatially random potential.
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Яремчук, О. М., та А. В. Кулік. "ГЕНЕЗИС ТА ОСОБЛИВОСТІ ФОРМУВАННЯ БАЗОВИХ МОДЕЛЕЙ ІДЕНТИФІКАЦІЇ КОЛЬОРУ". Art and Design, № 3 (5 грудня 2019): 113–24. http://dx.doi.org/10.30857/2617-0272.2019.3.12.
Повний текст джерелаАнотація:
Purpose. The determination of the formation features of basic models of color and identification of color in the initial stages (the 18th – 19th centuries) of scientific research of the problem. Methodology of the research is based on historical and cultural method. The source base is the artistic, scientific and technical literature of the studied period and also artefacts. Results. This publication reveals a generalized approach to theoretical developments on color perception and identification, and covers the initial period of color research and the formation of basic models of color (the 18th – 19th centuries). So in the middle of the 17th century I. Newton founded a seven-color ordering model, placing them to a closed color circle. At about the same time, other attempts at color systemization were proposed, such as color identification in the form of tables of existing paints, the work of I. Brennen and R. Waller. Subsequently, Jacob Christoph Le Blon concluded that in order to get results, you could use only three colors, namely red, yellow and blue. Based on this work, M. Harris presented his color circle, J. Lambert – a triangular color pyramid, and Ph.Runge built a color sphere using the principle of the globe. Goethe, contrary to Newton's physical doctrine of colors, conceived another system, it was based on the phenomenological perception of color. According to Goethe and his followers, the colors come from the struggle of "light" and "darkness". A. Schopenhauer took the step that J. Goethe lacked in his thinking: A. Schopenhauer formed a doctrine of color in terms of psychology, noting the enormous role that our brain plays in color perception, and proposing his model of identification by the principle of intensity / extensiveness/quality. for the formal description of the tri-color system of color, forming a mathe-confirmation of T. Young's theory and came to the conclusion that for the comparison of all shades, three light sources were needed and sufficient: in the red, green and blue parts of the spectrum. The perception of other colors is conditioned by the interaction of these constituents. In his work, J. Maxwell proved that all colors come from a mixture of three spectral colors: red, green, and blue. Based on his research, he introduced the first two-dimensional color spectrum visualization system. H. Grassmann's merit is the mathematical representation of the three spectral colors. E. Hering's theory highlights the psychological aspects of color vision: warm sensations occur for white, yellow, and red colors, while cold sensations occur for black, dark blue, and light blue. G. Peano introduced the concept of "color space" as a system of vector space equations.
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Langlais, Joseph, and Alain Lemieux. "The SEED Technology for Semi-Solid Processing of Aluminum Alloys: A Metallurgical and Process Overview." Solid State Phenomena 116-117 (October 2006): 472–77. http://dx.doi.org/10.4028/www.scientific.net/ssp.116-117.472.
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As part of the foundry technology program, Alcan is developing a liquid-based slurrymaking process known as the SEED technology for semi-solid forming. The technology is presently entering the industrial and commercial stages, and will be used by the first customers in late 2006. The semi-solid process offers many advantages to economically fabricate near-net-shape parts having superior quality. The SEED process helps to overcome problems experienced with thixocasting and especially the high cost of feedstock. The SEED process involves two main steps: 1) heat extraction to achieve a desired liquid/solid mixture, and 2) drainage of an excess liquid to produce a self-supporting semi-solid slug that is formed under pressure. An overview of the industrial SEED technology advantages such as the alloy processing flexibility (A356, AA6061) and large slug dimensions and weights, is presented. The influence of the SEED processing parameters (slurry preparation) on the final mechanical properties and the microstructure evolution is also reported.
Дисертації з теми "Foundry form, forming mixture"
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Буряк, Андрій Андрійович. "Розроблення технологічного процесу виготовлення чавунного виливка «Корпус», організація та планування формувального відділення ливарного цеху". Bachelor's thesis, КПІ ім. Ігоря Сікорського, 2021. https://ela.kpi.ua/handle/123456789/43671.
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Дипломний проект містить 92 стор., 22 табл., 10 рис., 8 посилань.
Об'єкт проектування – технологічний процес виготовлення виливка з
вуглецевої сталі «Корпус» масою 3,04 кг литтям у разові піщано-глинясті форми.
Предмет проектування – технологія ливарної форми та організація роботи
формувального відділення ливарного цеху.
Результатами проектування є розроблення технології ливарної форми для
заданого виливка, виконання технічного планування формувального відділення та
розрахунок одиниці ливарного устаткування.
Результати проектування – можуть бути рекомендовані на ливарних
підприємствах з подібним характером виробництва.
Галузь використання – підприємства машинобудування, військово промислового комплексу і т.п.Thesis project: pages, 22 tables, 10 figures, 9 references. The object of design - the technological process of manufacturing a carbon steel casting "Gearbox housing" weighing 3,04 kg by casting in disposable sand claymolds. The subject of design - the technology of the mold and the organization of the molding department of the foundry. Design results - the technology of the casting mold for a given casting is developed, the technical planning of the molding department and the calculation ofthe unit of the casting equipment are performed. Design results - can be recommended at foundries with a similar nature of production. Field of use - enterprises of agricultural engineering, military-industrial complex, etc.
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Басов, М. В. "Забезпечення екологічної безпеки ливарно-механічних виробництв". Thesis, Івано-Франківський національний технічний університет нафти і газу, 2014. http://elar.nung.edu.ua/handle/123456789/4666.
Повний текст джерелаАнотація:
Дисертаційна робота присвячена забезпеченню екологічної безпеки ливарно-механічних виробництв. Проведено аналіз джерел екологічної небезпеки ливарних виробництв та перспективних шляхів мінімізації їх негативного впливу на довкілля. Запропоновано стратегію створення екологічно безпечних та економічно виправданих формувальних сумішей, здатних до регенерації; для цих сумішей встановлено оптимальний склад та раціональну технологію їх використання та регенерації. Побудовано математичну модель руху потоків пилу в пиловловлювачі з жалюзійним відокремлювачем, який обертається, проведено аналіз картини руху потоків та визначено оптимальні параметри роботи апаратів. Створено комплект високоефективного пиловловлюючого обладнання для очищення повітря від дрібнодисперсного пилу в ливарно-механічних виробництвах, запропоновано конструкції пиловловлювачів, які захищені патентами України. Проведено комплексні експериментальні дослідження запропонованих пиловловлювачів на стенді, у результаті досліджень визначено раціональні параметри роботи пиловловлювачів із відокремлювачем, який обертається.Диссертационная работа посвящена обеспечению экологической безопасности литейно-механических производств. Проведен анализ источников экологической опасности литейных производств и перспективные пути минимизации их отрицательного влияния на окружающую среду. Предложена стратегия создания экологически безопасных и экономически оправданных формовочных смесей, способных к регенерации. С этой целью в состав смесей предложено вводить добавку гидроалюмосиликатов с определенной степенью дегидратации. С участием этой добавки и жидкого стекла, которое входит в состав смеси, образуется кристаллическая фаза, которая не спекается с зернами песка. Поэтому песок в классификаторе может отделяться от отработанных форм и использоваться для создания новых формовочных смесей. В качестве такой добавки предложен многотоннажный отход промышленности огнеупоров - шамотнокаолиновая пыль. Установлен оптимальный состав формовочных смесей и рациональная технология их использования и регенерации. Для уменьшения загрязнения атмосферы тонкодисперсной пылью -сконденсированными частицами оксидов металлов, - которые используются в литье, предложено использовать пылеуловители с вращающимся жалюзийным отделителем, в котором реализуются 4 степени очистки: центробежная очистка пылегазового потока после входа его в аппарат аналогично циклону; расположение жалюзийного пылеотделителя коаксионно оси корпуса аппарата как второй степени очистки; определенная форма жалюзи пылеотделителя как третьей степени очистки и доочистка газовой смеси от мелкодисперсной пыли за счет определенным образом организованного вращения жалюзийного пылеотделителя. Построена математическая модель движения потоков пыли в пылеуловителе с жалюзийным отделителем, который вращается, анализ которой позволил определить оптимальное направление вращения жалюзийного пылеотделителя - навстречу движению газового потока во входном отверстии с угловой скоростью 5 рад/с. Проведен анализ картины движения потоков и определены оптимальные параметры работы аппаратов. Создан комплект высокоэффективного пылеулавливающего оборудования для очистки воздуха от мелкодисперсной пыли в литейно-механических производствах; предложенные конструкции пылеуловителей защищены патентами Украины. Проведены комплексные экспериментальные исследования предложенных пылеуловителей на стенде, в результате исследований определены рациональные параметры работы пылеуловителей с отделителем, который вращается. Разработанные конструкции внедрены на ООО «Литейно-механический завод «Веста». Результаты исследований подтвердили эффективность разработок и перспективность их применения для обеспечения экологической безопасности литейных производств.
The dissertation deals with providing of ecological safety of foundry-mechanical industries. The analysis of sources of ecological dangeries of foundry-mechanical industries and promising ways of their dangerous influence minimization on the environment were observed. The strategy of creating ecologically safe and economically proved forming mixtures, possible for regeneration were supposed. Optimal structure , effective technology of usage and regeneration were determined. The mathematical model of dust stream movement in dust collector with stirred jalousie separator, the analysis of flow movement and optimum parameters of apparatus work were developed. A complete set of high-effective dustcollective apparatus for air cleaning from fme-dyspersated dust in foundry-mechanical industries and constructions of dust collectors protected by Ukrainian patents were supposed. Complex experimental investigations of supposed dust collectors on test bench were implemented. As a result of investigations rational parameters of dust collectors work with stirred separator were determined.
Книги з теми "Foundry form, forming mixture"
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The World Market for Machinery for Agglomerating, Shaping, or Molding Solid Mineral Fuels and Ceramic Pastes in Powder or Paste Form and for Forming Sand Foundry Molds: A 2004 Global Trade Perspective. Icon Group International, Inc., 2005.
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Parker, Philip M. The World Market for Machinery for Agglomerating, Shaping, or Molding Solid Mineral Fuels and Ceramic Pastes in Powder or Paste Form and for Forming Sand Foundry Molds: A 2007 Global Trade Perspective. ICON Group International, Inc., 2006.
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3
Parker, Philip M. The 2007 Import and Export Market for Machinery for Agglomerating, Shaping, or Molding Solid Mineral Fuels and Ceramic Pastes in Powder or Paste Form and for Forming Sand Foundry Molds in China. ICON Group International, Inc., 2006.
Знайти повний текст джерелаЧастини книг з теми "Foundry form, forming mixture"
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Taber, Douglass F. "The Williams Synthesis of (-)-4-Hydroxydictyolactone." In Organic Synthesis. Oxford University Press, 2013. http://dx.doi.org/10.1093/oso/9780199965724.003.0083.
Повний текст джерелаАнотація:
(-)-4-Hydroxydictyolactone 3, representative of the cyclononene xenicanes isolated from the Dictyotacae algae, readily isomerizes thermally to the more stable ( Z )- 6,7-isomer. Attempts to directly form this strained ring system appeared to be fraught with difficulty. David R. Williams of Indiana University envisoned (J. Am. Chem. Soc. 2009, 131, 9038) that use of Suzuki coupling might ameliorate some of the strain, since at the point of commitment to bond formation, the Pd center would be included in the forming ring. This analysis led specifically to the trans ether 1, as cyclization of the trans ether appeared likely to be more facile than would cyclization of the alternative cis diastereomer. The first challenge was the assembly of the array the four contiguous alkylated stereogenic centers of 1. To this end, the Z secondary ester 7 was prepared from the acetonide 4 , available from mannitol, and ( R )-(+)-citronellic acid, prepared by oxidation of the commercial aldehyde. Addition of 7 to LDA led to decomposition, but inverse addition of LDA to a mixture of the ester, TMSCl, and Et3 N smoothly delivered the ketene silyl acetal. On warming, Ireland-Claisen rearrangement of the ketene silyl acetal led to the acid 8 with remarkable diastereocontrol. The last alkylated stereogenic center of 1 was installed by reductive cyclization of the formate ester 9. Again, the cyclization proceeded with remarkable diastererocontrol. Although the intramolecular reaction of in situ prepared allyl metals is well precedented, the addition to a formate ester had not previously been reported. Although 11 appears to be ready for the long-awaited Suzuki coupling, in fact the TIPS protecting group substantially slowed hydroboration. The free alcohol/methyl acetal was the best substrate for hydroboration, but the free alcohol entered into other side reactions. After extensive experimentation, a happy medium was found with the methyl acetal/TBS ether 1. Selenylation of the lactone 12 followed by oxidative elimination of the selenide delivered the expected Z alkene. Removal of the silyl protecting group had to precede introduction of the second alkene, as the product 3 deteriorated rapidly on exposure to the alkaline conditions of TBAF cleavage.
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Dalton, David R. "More Than Skin Deep." In The Chemistry of Wine. Oxford University Press, 2018. http://dx.doi.org/10.1093/oso/9780190687199.003.0027.
Повний текст джерелаАнотація:
The grape berry is composed of skin, flesh (pulp) and seeds. After destemming (Chapter 13), the grapes are sent on for crushing. On crushing, the thick walls of the skin, including the waxy cuticle, are broken. Crushing the grapes (Figure 16.1) is a question of quantity. Small quantities are handled differently than large. The skins, including the contaminants thereon, as well as the majority of the materials discussed above for the individual grapes (i.e., phenols, anthocyanins, tanins, some acids, terpenes, pyrazines, and some carbohydrates including those attached to the anthocyanidins, forming anthocyanins) therein, are released. The cells of the pulp are also broken and released into the juice on crushing. This berry cell juice is mainly water (70–80% by weight) which contains the mixture of sugars (mostly glucose and fructose, but small concentrations of many other carbohydrates are also present), carboxylic acids (mostly tartaric and malic, but additional members of the tricarboxylic acid cycle, oxalic, glucuronic, etc. are also present), complex cross-linked polysaccharides from cell walls (pectins), some phenols and proteins (as well as the peptides and simple amino acids from which they are constructed), and minerals, including oxides of iron (Fe), phosphorus (P), and sulfur (S), as well as salts of potassium (K) and sodium (Na) brought up in the xylem to the growing berry. The seeds have their cellulose carbohydrate-based exterior coatings, which are also rich in complexed polyphenols (tannins). Additionally, amino acids, generally found as constituents of peptides, proteins, and enzymes, and their cofactors needed for all life, nucleic acids and their attached sugars needed for the next generation, are all present too. Thus, overall, the result of crushing the berries is a mixture consisting of skins, seeds, and fruit juice (the must = Latin vinum mustum = young wine). This mixture may, if the grapes were “white,” be cooled and the cap on the must—sometimes called the pomace (the solid portion of the must) removed early or late (usually between 12 and 24 hours) by the vintner. Most of the flavoring constituents are quickly extracted, and brightly colored phenols, tannins, anthocyanins, etc.
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Maletin, Yuriy A., Natalia G. Stryzhakova, Sergii O. Zelinskyi, Anatoliy O. Lysenko, Valentyna E. Goba, Oleg V. Gozhenko, and Andriy Yu Maletin. "Modification of nanoporous structure and surface of carbon electrodes for use in power storage systems." In NEW FUNCTIONAL SUBSTANCES AND MATERIALS FOR CHEMICAL ENGINEERING, 119–29. PH “Akademperiodyka”, 2021. http://dx.doi.org/10.15407/akademperiodyka.444.119.
Повний текст джерелаАнотація:
Method for modification of nanoporous structure and surface of carbon materials to be used as supercapacitor electrodes has been developed and optimized as to the microwave treatment (MWT) regimes. Mechanisms of MWT due to the dielectric and Maxwell-Wagner polarization effects have been discussed. It has been found that due to the dielectric polarization and a fast increase in temperature inside pores, which were saturated with etching agents (water, oxalic or formic acid) beforehand, the selective pore etching “from inside” can occur that increases the pore size and, as a result, increases the electrostatic capacitance of supercapacitors by 20%. Processes of pore structure development have been optimized as to the treatment duration and the carbon material grain size. It has also been shown that the pore surface can be modified with Nitrogen heteroatoms due to the MWT of carbon and melamine powder mixtures. This modification enables to step up the supercapacitor rated voltage from commonly used 2.7V to 3.0V that additionally increases the supercapacitor energy density by 23%. Yet another advantage of MWT is a significant reduction in treatment duration (from hours to minutes) and in energy consumption; besides, the loss of carbon material does not exceed 10% due to the mostly “from inside” etching process.
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Bunker, Bruce C., and William H. Casey. "Nucleation and Growth of Solid Oxide and Hydroxide Phases." In The Aqueous Chemistry of Oxides. Oxford University Press, 2016. http://dx.doi.org/10.1093/oso/9780199384259.003.0013.
Повний текст джерелаАнотація:
In this chapter, we consider what happens when solids begin to form from solution. To grow solids from solution, solution conditions are changed from a condition in which all species are completely soluble to a condition in which they are insoluble. In the context of hydrolysis diagrams, the solution composition moves in pH and total dissolved metal concentration from a regime below a solubility or saturation limit (given by the bold solid line in Figs. 5.2 and 5.3) to a regime above this limit where the solution is supersaturated. Supersaturated solutions are inherently unstable and have the potential to generate hydroxide or oxide solids. Sometimes these solutions can be maintained in a metastable state in which precipitation does not occur immediately. However, Mother Nature eventually reduces the energy of the solution by forming a stable mixture of solids plus solution species. As solids form, soluble complexes are removed from solution until concentrations drop back to the solubility limit. The precipitation of a solid from an aqueous solution is a surprisingly complex process, involving nucleation and growth phenomena that occur at nanometer-length scales. Nucleation involves reactions between oligomers to form new clusters or particles that are sufficiently large that they do not redissolve spontaneously via the reversible reactions denoted in hydrolysis diagrams. Homogeneous and heterogeneous nucleation processes represent events that occur within the bulk solution or at the interface of another phase, respectively. Growth involves the addition of monomers to clusters in solution or oligomers to existing particles or surfaces. The combination of nucleation and growth phenomena can lead to oxides exhibiting a bewildering range of sizes, shapes, and crystal structures. How do metal complexes decide whether to form a new particle or add to an existing particle? What determines the size, shape, and crystal structure of evolving particles? Do the particles aggregate with one another in an organized fashion? Because nucleation typically involves extremely rapid (<1 millisecond) events involving objects that are extremely small (on the order of a nanometer), it is difficult to probe such phenomena at a molecular level.
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Taber, Douglass. "Developments in Alkene Metathesis." In Organic Synthesis. Oxford University Press, 2011. http://dx.doi.org/10.1093/oso/9780199764549.003.0024.
Повний текст джерелаАнотація:
Alkene metathesis has been extended to increasingly complex starting materials and products. Nitriles are good donors to coordinatively-unsaturated transition metal centers, so tend to inhibit the reaction. Ren He of Dalian University of Technology has found (Tetrahedron Lett. 2007, 48, 4203) that inclusion of the loosely-coordinating 2-methyl pyridine in the reaction enables facile cross-coupling with acrylonitrile 2. Although crosscoupling with (Z, Z)-sorbate is not efficient, Dennis P. Curran of the University of Pittsburgh has shown (Organic Lett. 2007, 9, 5) that cross-coupling with (E, Z)-sorbate 5 works well. For large scale work, he has developed a Hoveyda-type catalyst with a perfluoro tail, that is recoverable in 70% recrystallized yield from the reaction mixture. Shigefumi Kuwahara of Tohoku University has reported (Tetrahedron Lett. 2007, 48, 3163) a practical alternative for direct metathesis to deliver (E, E)-dienyl esters. Continuing the investigation of tandem Ru-catalyzed reactions, Marc L. Snapper of Boston College effected (Organic Lett. 2007, 9, 1749) metathesis with methacrolein 8a, then added Ph3P and diazoacetate, to give the diene 11. A range of common Ru catalysts worked well for this transformation. In an alternative approach to trisubstituted alkene construction, Stellios Arseniyadis and Janine Cossy of ESPCI Paris have demonstrated (Organic Lett. 2007, 9, 1695) that inclusion of Cl-catecholborane 14 allows clean cross metathesis with the lactone 13. The construction of tetrasubstituted alkenes has been more challenging. Yann Schrodi of Materia, Inc. (Organic Lett. 2007, 9, 1589) has described a catalyst 17 that is particularly effective. Complex 17 was superior to a catalyst reported (Organic Lett. 2007, 9, 1339) shortly earlier by Robert H. Grubbs of Caltech. Debendra K. Mohapatra of the National Chemical Laboratory, Pune, and Professor Grubbs, in a new approach to macrocyclic stereocontrol, have made (Tetrahedron Lett. 2007, 48, 2621) the remarkable observation that the cyclization of the bis ether 19a gave 20 in a 9:1 E / Z ratio, while cyclization of the diol 9b gave only Z - 21. Oligomer formation can often compete in such medium ring-forming reactions. Deryn E. Fogg of the University of Ottawa has raised (J. Am. Chem. Soc. 2007, 129, 1024) the cautionary (but happy!) observation that while the cyclization, for instance, of 22 proceeded efficiently to give 23, at an intermediate point in the transformation the product was more than half oligomer.
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Taber, Douglass F. "The Dixon Synthesis of (-)-Nakadomarin A." In Organic Synthesis. Oxford University Press, 2013. http://dx.doi.org/10.1093/oso/9780199965724.003.0087.
Повний текст джерелаАнотація:
(-)-Nakadomarin A 4, isolated from the sponge Amphimedon sp. off the coast of Okinawa, shows interesting antifungal and antibacterial activity. The key step in the total synthesis of 4 reported (J. Am. Chem. Soc. 2009, 131, 16632) by Darren J. Dixon of the University of Oxford was the diastereoselective addition of the enantiomerically pure ester 1 to the prochiral nitroalkene 2. The assembly of 2 began with the linchpin ketophosphonate 5. Alkylation of the dianion of 5 with allyl bromide followed by direct condensation of the resulting monoanion with the diacetate 6 gave 7. On exposure to aqueous acid, 7 cyclized to the furan. Oxidation of the liberated primary alcohol followed by condensation with nitromethane then completed the preparation of 2. The starting material for the synthesis of 1 was the enantiomerically pure pyroglutamate derivative 8. Sulfide displacement followed by N-alkylation with the bromide 10 delivered 11 . Oxidation followed by deprotection then set the stage for the intramolecular Julia-Kocienski cyclization, which gave 12 with the expected (eight-membered ring) high geometric control. Addition of the ester 1 to Michael acceptors proceeded across the open face of the lactam, but it was still necessary to control the face of the nitro alkene 2 to which the lactam anion added. Catalysis of the addition with the urea 13 delivered 3 with 10:1 diasterocontrol. Mannich condensation of the nitroalkane 3 with formaldehyde and the amine 14 gave the bis-lactam 15, conveniently as a single diastereomer. After free radical removal of the nitro group, it was necessary to achieve selective reduction of the δ-lactam in the presence of the γ-lactam. Low-temperature LiAlH4 was found to be effective. Direct reduction of the resulting hemiaminal with formic acid led to the monolactam 16. The hemiaminal from monoreduction of 16 was found to be unstable and sensitive to overreduction. Nevertheless, exposure of 16 to Dibal at low temperature followed by acid-mediated cyclization delivered the diamine 17. Cyclization of the free base of 17 with the first generation Grubbs catalyst gave (-)-nakadomarin A 4 as the minor component of a 40:60 Z/E mixture. Carrying out the cyclization on the camphorsulfonate salt improved the ratio to 63:37 Z/E.
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Taber, Douglass F. "The Ding Synthesis of Steenkrotin A." In Organic Synthesis. Oxford University Press, 2017. http://dx.doi.org/10.1093/oso/9780190646165.003.0106.
Повний текст джерелаАнотація:
Steenkrotin A 3 was isolated from Croton steenkampianus Gerstner, widely used in folk medicine for the treatment of coughs, fever, malaria, and rheumatism. Hanfeng Ding of Zhejiang University envisioned (Angew. Chem. Int. Ed. 2015, 54, 6905) that the intriguingly compact core of 3 could be assembled by reductive cyclization of the aldehyde 1 to 2, followed by intramolecular aldol condensation. The diastereoselective assembly of 1 from the cycloheptenone core 4 depended on the conformational preferences of the seven-membered ring. Enol ether formation followed by Rubottom oxidation led to the silyl ether 5. Oxidative rearrangement of the tertiary alcohol generated by 1,2-addition to 5 of in situ generated allyl lithium established the enone 6. Again taking advantage of the conformational preference of the seven-membered ring, cyclopropanation of the silyl enol ether derived from 6 proceeded across the open face of the electron-rich alkene to give 7. The other oxygenated quaternary center of 1 was constructed by O-alkylation of 7 with diazo malonate followed by methylation and reduction. Acetylation of the diol 8 proceeded with 10:1 diastereoselectivity, to give, after oxidation, the aldehyde 9. In the first of a sequence of three intramolecular bond-forming reactions, HF.py cyclized the aldehyde onto the endocyclic alkene, and also freed the alcohol, that was alkylated with the dibromide 10 to give 11 as a 1.5:1 mixture of diastereomers. On exposure to SmI2, the major diastereomer cyclized to give a intermediate that was carried on to 1. The minor diastereomer was merely reduced, to a product that could be recycled to 11. With 1 in hand, the stage was set for the second intramolecular cyclization. Even though 1 was predominantly in the lactol form, there was enough of an equilibrium concentration of aldehyde present for the SmI2-mediated cyclization to proceed smoothly to 2. With 2 in hand, in addition to the last intramolecular cyclization, the two stereogenic centers (marked by an asterisk) had to be inverted. The methyl group adjacent to the ketone was readily equilibrated. The secondary alcohol could be inverted by late-stage oxidation and reduction, and the authors did do that. However, they also observed a small amount of the desired epimeric alcohol 14 from the intramolecular aldol condensation of 12.
8
"nose family of sugars [178]. Total free sugar content of rye from tubers and roots, particularly potato, sweet potato, and was reported as 3.2%, with sucrose (1.9%), raffinose tapioca (cassava). Isolated starch can be modified physical-(0.4%), fructose (0.1%), and glucose (0.08%) [120]. ly and/or chemically to alter its functional properties. Starches and modified starches have an enormous number Ill. STARCH of food uses, including adhesive, binding, clouding, dust-ing, film forming, and thickening applications [20]. Starch is found in a number of plant sources, and the plant relies on starch for its energy requirements for growth and reproduction. For humans, starch is extremely important as A. Starch Content of Cereals a macronutrient, because it is a complex carbohydrate and The most important sources of starch are cereal grains an important energy source in our diet. (40-90% of their dry weight), pulses (30-70%), and tubers The commercial and technological uses of starch are (65-85%). Of the common starches, regular corn, waxy numerous; this arises from its unique character, because it corn, and high-amylose corn are by far the most important can be used directly as intact granules, in the dispersed sources. The starch content of corn may vary from about form, as a film dried from a dispersion, as an extruded 54% in sweet corn to 64-78% in dent [194]. Corn is large-powder, or after conversion to a mixture of oligosaccha-ly used as stock feed but nevertheless supplies the bulk, by rides or via hydrolysis and isomerization. far, of the world's starch production. Corn starch is manu-When starch is heated in water, it absorbs water and factured by traditional wet-milling process. Only about 5% swells. This is the process of gelatinization, a process that of the annual world maize crop is used for the manufacture cause a tremendous change in rheological properties of the of maize starch. About 70% of the maize starch produced starch suspension. The crystalline structure is destroyed is converted into corn syrups, high-fructose corn syrup, during gelatinization. The ability of starch molecules to and dextrose. Corn starch has a wide variety of industrial crystallize after gelatinization is described by the term of applications, with uses ranging from thickening and retrogradation. Although some retrogradation of amylose gelling agents in puddings and fillings to molding for con-seems to be a prerequisite for the formation of a normal fections [72]. bread crumb, long-term retrogradation usually causes Potato starch is a variable commodity, sensitive to vari-gradual deterioration of bread quality during the products' ety, climate, and agricultural procedure. Potato starch, shelf life [55]. however, is presently second only to corn and comparable Starch occurs as discrete granules in higher plants. Two to wheat in terms of quantity produced and especially pop-major polymers, amylose and amylopectin, are contained in ular in Europe. About 3% of the world crop of potatoes is the granule. Cereal starch granules may also contain small used for the production of potato starch. Potato starch is amounts of proteins, lipids, and minerals [118]. Cereal used in food, paper, textile, and adhesive industries. starches are widely used in foods, where they are important The starch content of wheat has been reported to be in functionally and nutritionally. Commercial starches are ob-the range of 63-72% [147] (Table 2). Wheat starch, found tained from cereal grain seeds, particularly from corn, waxy in the endosperm of the wheat kernel, constitutes approxi-corn, high-amylose corn, wheat, and various rites, and mately 75-80% of the endosperm on a dry basis. The TABLE 2 Carbohydrate Composition of Some Cereal Grains' Sample Starch (%) Amylose (%) Pentosan (%) P-Glucan (%) Total dietary fiber Wheat 63-72 (147) 23.4-27.6 (133) 6.6 (81) 1.4 (151) 14.6 (32) Barley 57.6-59.5 (87) 22-26 (27) 5.9 (82) 3-7 (139) 19.3-22.6 (87) Brown rice 66.4 (104) 16-33 (124) 1.2 (81) 0.11 (102) 3.9 (32) Milled rice 77.6 (104) 7-33 (102) 0.5-1.4 (104) 0.11 (104) 2.4 (32) Sorghum 60-77 (194) 21-28 (127) 1.8-4.9 (127) 1.0 (151) 10.1 (160) Pearl Millet 63 (123) 17 (11) 2-3 (12) 8.5 (32) Corn 64-78 (194) 24 (132) 5.8-6.6 (194) 13.4 (32) Oats 43-61 (143) 16-27 (120) 7.7 (81) 3.9-6.8 (198) 9.6 (32) Rye 69 (168) 24-31 (168) 8.5 (81) 1.9-2.9 (151) 14.6 (32) Triticale 53 (22) 24-26 (40) 7.1 (81) 1.2 (151) 18.1 (32) aSources shown in parentheses." In Handbook of Cereal Science and Technology, Revised and Expanded, 403–4. CRC Press, 2000. http://dx.doi.org/10.1201/9781420027228-40.
Повний текст джерелаТези доповідей конференцій з теми "Foundry form, forming mixture"
1
Otake, Shiro, Masahiro Nishimura, and Ken-ichiro Sugiyama. "Oxidization and Combustion in Liquid Sodium Droplet." In 17th International Conference on Nuclear Engineering. ASMEDC, 2009. http://dx.doi.org/10.1115/icone17-75250.
Повний текст джерелаАнотація:
Liquid sodium is used as the coolant of the fast reactor because of its high thermal conductivity. It is superior as thermal medium in spite of high chemical reactivity with oxygen. In many cases, the combustion starts after forming the dendrite oxides on its reaction surface in oxygen atmosphere. This fact indicates that sodium doesn’t ignite and burn easily unless dendrite oxides are formed. The understanding of the formation mechanism of the dendrite oxides helps us to obtain the optimum handling of leftover non-burning sodium after the accident. However, experimental knowledge to understand the mechanism of combustion is still insufficient. The purpose of this study is to clarify the oxidization behavior of a liquid sodium droplet precisely [1]. The reason why we choose the droplet form is derived from the fact that the reaction surface can be easily observed. The experiment was carried out in a glove box filled with argon gas. A single sodium droplet was made at the tip of the nozzle and preheated at the experimental temperature. The oxidization started by supplying the gas mixture of nitrogen and oxygen. The oxygen concentration of the gas mixture and the initial sodium temperature were adopted as experimental parameters, 4% ∼ 20% O2 and 200°C ∼ 500°C respectively. When the gas mixture was supplied, the droplet surface was covered with a white oxide layer. Gradually, the dendrite oxides appeared on the lower side of the sodium droplet, and the aerosol was generated in the vapor phase area. Then, the dendrite oxides on the surface sank in the droplet and the surface became smooth again. Finally the sodium droplet was encompassed by orange flame. The dendrite oxides were found to grow bigger at the first reaction period. It is suggested that the dendrite oxides have a porous structure and the liquid sodium in the droplet is drawn up to their tips by capillary force. Then the sodium oxidization occurs at the tips. The sodium droplet covered by dendrite oxides was also found to be heated up and the dendrite oxides sank into the droplet due to the high oxygen solubility and be finally burned due to the attainment of its ignition temperature as the second reaction period. The heat generation of oxidization as the first reaction period contributed to the combustion phenomena.
2
Ninan, Chinnu Mariam, K. P. Ramaswamy, and R. Sajeeb. "Influence of Concrete Mixture Composition on Acid Resistance of Concrete: A Review." In International Web Conference in Civil Engineering for a Sustainable Planet. AIJR Publisher, 2021. http://dx.doi.org/10.21467/proceedings.112.53.
Повний текст джерелаАнотація:
Cementitious materials are highly susceptible to rapid and severe degradation by a wide range of acids that are found immensely in ground water, sewage systems, industrial effluents, acid rain etc. which may cause microstructure deterioration. The factors influencing acid attack is generally categorised as material related factors and test related factors. Material related factors can be either related to acid solution or concrete mixture composition. Composition of concrete mixture greatly impacts the acid resistance of concrete. Factors related to composition of concrete mixture are type of cement, type and proportion of binders, water binder ratio, aggregate binder ratio and mineralogical nature of the aggregates. Even though the type of cement influences acid attack, the magnitude of variation is negligible. Consumption of calcium hydroxide and refinement of pore structure makes the use of supplementary cementitious materials favourable for acid resistance. Decrease in water binder ratio and increase in aggregate binder ratio reduces the porosity of concrete and thereby improves the acid resistance of concrete. Calcareous aggregates are preferred for concretes exposed to acids having less soluble salts and not preferred for acids forming soluble salts. This paper highlights the influence of composition of concrete mixture on acid resistance of concrete. A proper formulation of concrete is expected to enhance its acid resistance.
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Voloshin, Aleksander, Nikolay Nifantiev, Mikhail Egorov, Robert Alimbekov, and Vladimir Dokichev. "Development and Implementation of Green Inhibitors of Gas Hydrate Formation in the Fields of Western Siberia." In SPE Russian Petroleum Technology Conference. SPE, 2021. http://dx.doi.org/10.2118/206470-ms.
Повний текст джерелаАнотація:
Abstract The effect of biodegradable polysaccharides – sodium (NaCMC) and ethanolammonium salts of carboxymethylcellulose, dextran and arabinogalactan on the process of gas hydrate formation was studied in order to search for new "green" inhibitors of low-concentration gas hydrate formation. The ability of polysaccharides to inhibit gas hydrate formation was studied in a quasi-equilibrium thermodynamic experiment. A mixture of hydrocarbon gases with a composition typical of the composition of petroleum gas and containing 78% methane was used as a gas-hydrate-forming model medium. It was found that in concentrations of 0.005, 0.0065 and 0.008%, dextran, NaCMC and arabinogalactan as thermodynamic inhibitors exceed methanol by 170-270 times in inhibitory properties. Dextran is superior to NaCMC and arabinogalactan in terms of inhibition efficiency, reduction of gas hydrate formation rate and induction time. Since with an increase in the concentration of polysaccharides, the pressure drop of gas hydrate formation increases and the rate of formation of gas hydrates decreases according to the mechanism of action, the studied polysaccharides can be attributed to both thermodynamic and kinetic inhibitors. It is established that the molecular weight of water-soluble polysaccharides has a significant effect on their inhibitory properties. A polysaccharide with a molecular weight of 250,000 demonstrated the highest inhibitory activity among the studied samples of NaCMC, which is 400 times more effective than methanol. NaCMC with a mass of 700 thousand did not have any effect on the formation of hydrates. Among the ethanolammonium salts, the monoethanolammonium salt CMC showed the greatest effectiveness in inhibiting the formation of tetrahydrofuran hydrates. An increase in its concentration from 0.02 to 0.1% leads to an increase in the induction time required for the nucleation and subsequent growth of crystals by 10 times. When switching from mono - to di - and triethanolammonium salts of carboxymethylcellulose, the inhibition efficiency decreases. It is shown that sodium and ethanolammonium salts of carboxymethylcellulose, arabinogalactan and dextran are promising for creating new "green" highly effective inhibitors of gas hydrate formation on their basis. The results of laboratory and field tests of the preparative form of the "green" gas hydrate formation inhibitor at the fields of Western Siberia are presented. It was found that at dosages of 500 g/m3 or less, there is no formation of hydrate plugs in the annulus of wells.
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Parasumanna, Ajeet. "Bimetal Mixture Forging Process and Its Influence on Intermetallic Phase Seam Properties for An Automotive Component." In FISITA World Congress 2021. FISITA, 2021. http://dx.doi.org/10.46720/f2020-mml-052.
Повний текст джерелаАнотація:
In today’s scenario, the fuel cost and stricter norms related to environmental protection are exponentially increasing and thus lightweight forging is gaining importance which directly enhances the efficiency of the entire vehicle leading to reduction in pollution and fuel consumption. Material substitution with lighter alloy is one of the solutions but the part design is a constraint to implement this approach in structural load bearing parts which undergoes dynamic loading in its lifecycle. Mixture forging is a solid / Semi solid hot-forming process of two different materials while plastic deformation occurs. In mixture forging of steel-aluminum parts there is a formation of intermetallic phases and the diffusion occurs between two materials. This paper is addressing the challenges in forging process and especially producing bimetal product by adapting to currently followed forging practices and infrastructure. In this study, a component forging process is designed using finite element computation tool and then forged in two stages followed by application of mixture forging concept during forging operation to achieve light weighting. The two different materials used are 42CrMo4 steel for high strength at the outer case and AA6061 aluminium alloy for a lightweight core. The thickness of the intermetallic phase seam achieved is less than 10 μm and its material characterisation is carried out using SEM analysis. Micro-hardness measurement was taken of the intermetallic phase and is found to be 855 (HV 0.01) which is brittle in nature. The component thus forged is found to be 27% lighter than the component produced by steel forging. This technology is a part of the multi material joining technology using forging process wherein conventional equipment can be used. The bulk forming process achieving multi material solution is a innovative process and can lead to lighweighting of various circular parts and shaft primarily in the transmission of ICE and Electric Vehicles.
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Liu, Jian-Hong, Fu-Min Shang, and Nikolay Efimov. "Numerical Study on Flow and Heat and Mass Transfer in Pulsating Heat Pipe." In ASME 2019 6th International Conference on Micro/Nanoscale Heat and Mass Transfer. American Society of Mechanical Engineers, 2019. http://dx.doi.org/10.1115/mnhmt2019-4012.
Повний текст джерелаАнотація:
Abstract Numerical simulation was performed to establishing a two-dimensional pulsating heat pipe model, to investigate the flow and heat transfer characteristics in the pulsating heat pipe by using the Mixture and Euler models, which were unsteady models of vapor-liquid two-phase, based on the control-volume numerical procedure utilizing the semi-implicit method. Through comparing and analyzing the volume fraction and velocity magnitude of gas phase to decide which model was more suitable for numerical simulation of the pulsating heat pipe in heat and mass transfer research. It was showed there had gas phase forming in stable circulation flow in the heating section, the adiabatic section using the Mixture and Euler models respectively, and they were all in a fluctuating state at 10s, besides, the pulsating heat pipe had been starting up at 1s and stabilizing at 5s, it was all found that small bubbles in the heat pipe coalescing into large bubbles and gradually forming into liquid plugs and gas columns from the contours of volume fraction of the gas phase; through comparing the contours of gas phase velocity, it could be seen that there had further stably oscillating flow and relatively stabler gas-liquid two-phase running speed in the pulsating heat pipe used the Mixture model, the result was consistent with the conclusion of the paper[11] extremely, from this it could conclude that the Mixture model could be better simulate the vaporization-condensation process in the pulsating heat pipe, which could provide an effective theoretical support for further understanding and studying the phase change heat and mass transfer mechanism of the pulsating heat pipe.
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Zheng, Dongsheng, Xin Hui, Xin Xue, and Weitao Liu. "Synergistic Effect of Soot Formation in Ethylene/Propane Co-Flow Diffusion Flames at Elevated Pressures." In ASME Turbo Expo 2021: Turbomachinery Technical Conference and Exposition. American Society of Mechanical Engineers, 2021. http://dx.doi.org/10.1115/gt2021-58622.
Повний текст джерелаАнотація:
Abstract The synergistic effect of soot formation refers to the interaction between different fuels during soot forming processes, which results in higher soot formation than any individual fuels. The present study experimentally investigates the synergistic effect of soot formation in co-flow diffusion flames of propane/ethylene fuel mixtures. The total carbon mass flow rate of the propane/ethylene mixture was kept constant at 0.5 mg/s, and the propane carbon ratio (RC) was defined as the ratio of carbon mass flow rate of propane to the total carbon mass flow rate. The laser-induced incandescence (LII) and light extinction (LE) techniques were applied to measure the soot volume fractions (SVF) at pressures of 0.1–0.5 MPa. The results showed strong synergistic effect in propane/ethylene mixtures at atmospheric conditions; however, increasing pressure weakens the synergistic effect. The LII intensity contours showed that the soot formation zone extends when synergistic effect occurs at RC = 0.1 and 0.2 for 0.1 and 0.3 Mpa. The normalized peak SVF showed that synergistic effect monotonically becomes weak with increasing pressure from 0.1 to 0.3 Mpa; meanwhile, the it still stayed strong at 0.2 Mpa when using normalized maximum soot yield, and then turned to be weaker as pressure increases. Further comparison analysis of the SVF profiles between RC = 0 and 0.1 revealed that the synergistic effect occurs at the two-wing area of the sooty flame at low axial flame height, and then gradually becomes stronger with increasing axial flame height in the soot zone for 0.1–0.3 Mpa. To illustrate the pressure effects on synergistic soot formation, numerical analysis in homogeneous closed reactor was conducted and it was found that The PAHs formation competition between C3H3 pathway and HACA mechanism results in the different soot formation phenomenon of ethylene/propane flames.
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Lewis, Ryan, M. H. Lin, Yunda Wang, Jill Cooper, Peter Bradley, Ray Radebaugh, Marcia Huber, and Y. C. Lee. "Demonstration of an Integrated Micro Cryogenic Cooler and Miniature Compressor for Cooling to 200 K." In ASME 2011 International Mechanical Engineering Congress and Exposition. ASMEDC, 2011. http://dx.doi.org/10.1115/imece2011-63908.
Повний текст джерелаАнотація:
Joule-Thompson (J-T) based micro cryogenic coolers (MCCs) are attractive because they can provide the cryogenic temperatures needed for small electronic devices while having a low cost and small volumetric footprint. A compressor is a major part of a cryogenic system, but so far J-T based MCCs have not used miniature or micro scale compressors. This work demonstrates a J-T based MCC coupled with a miniature compressor for cooling to 200 K, using a custom hydrocarbon mixture as refrigerant. The compressor is formed by coupling a miniature piston oscillator built for Stirling coolers with a micromachined check valve assembly. The MCC is formed by glass fibers within a capillary forming a counter flow heat exchanger, and a silicon and glass chip forming a J-T valve. Minimum temperatures of 166 K have been observed in transient, and stable temperatures of 200 ±1 K have been observed for >1 hour. Some insight is given into the unstable performance in terms of intermittent liquid accumulation. The coefficient of performance is analyzed for the system, and it is found that most of the inefficiencies arise at the compressor.
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Zhang, Li, Di Wang, Xian-Jin Liao, Xiao-Tao Luo, and Chang-Jiu Li. "The Influence of Diamond Addition to Ni-Al Powder on Oxidation Behavior of Ni-Al During Plasma Spraying for High Performance Oxide-Free Ni-Al Intermetallic Coating." In ITSC2021, edited by F. Azarmi, X. Chen, J. Cizek, C. Cojocaru, B. Jodoin, H. Koivuluoto, Y. C. Lau, et al. ASM International, 2021. http://dx.doi.org/10.31399/asm.cp.itsc2021p0447.
Повний текст джерелаАнотація:
Abstract Ni-Al intermetallics have excellent corrosion and oxidation resistance, but their use in thermal spraying has been limited due to issues with in-flight oxidation. In this study, a novel approach is proposed to remove oxide from Ni-Al droplets in-flight by adding a deoxidizer (diamond) to the feedstock powder. A mixture of nickel, aluminum, and diamond powders was mechanically alloyed using a combination of cryogenic and planetary ball milling. The resulting Ni/Al/diamond composite powder was then plasma sprayed via the APS process, forming Ni-Al coatings on Inconel 738 substrates. Phase composition, microstructure, porosity, and microhardness of the coatings were characterized by X-ray diffraction, scanning electron microscopy, image analysis, and hardness testing, respectively. Oxygen content measurements showed that the coatings contained significantly less oxygen than coatings made from ordinary Ni/Al powders. In-flight particle temperatures were also measured and found to be higher than 2300 °C. The low oxygen content in the coatings is attributed to the in-situ deoxidizing effect of ultrahigh temperature droplets which are also oxide-free.
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Robbins, K. C., and I. Boreisha. "COVALENT Mr ∼92,000 HYBRID PLASMINOGEN ACTIVATOR DERIVED FROM THE PLASMIN FIBRIN-BINDING DOMAIN AND THE TISSUE PLASMINOGEN ACTIVATOR CATALYTIC DOMAIN." In XIth International Congress on Thrombosis and Haemostasis. Schattauer GmbH, 1987. http://dx.doi.org/10.1055/s-0038-1643938.
Повний текст джерелаАнотація:
A covalent hybrid plasminogen activator was prepared from the sulfhydryl forms of the NH2-terminal A chain of human plasmin (Pln^) containing the fibrin-binding domain, and the COOH-terminal B chain of tissue plasminogen activator (t-PAB) containing the catalytic domain. The PlnA (SH)2 and t-PAB(SH) chains were mixed in a 1:1 molar ratio, and hybridization was allowed to proceed at 4 °C for 6 days. The covalent PlnA-t-PAB hybrid activator was isolated from the mixture by a two-step affinity chromatography method, with L-lysine-substituted Sepharose and Zn-chelated agarose. The protein yield of purified hybrid was 10% with a major component (77%) of Mr ∼92,000. The covalent PlnA-t-PAB hybrid activator, contained 1 mol of each chain; after reduction, it gave the two parent chains, PlnA and t-PAA, also shown to be present by double immunodiffusion. The specific plasminogen activator activity, with soluble fibrin, and the specific amidolytic activity, of the purified covalent hybrid activator was determined to be 200,000 IU/mg of protein, about 40% of the specific activity of the parent t-PA. In a fibrin clot lysis assay, the covalent hybrid activator and t-PA have similar specific fibrinolytic activities, 500,000 IU/mg of protein; however, the clot lysis time curves were not parallel. The binding of the covalent PlnA-t-PAB hybrid activator and t-PA to forming fibrin were found to be similar; at physiological fibrinogen concentrations, binding of both activators to forming fibrin was about 90%.
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Lee, S. G., N. K. Kalvan, J. Wilhelm, W.-T. Hum, R. Rappaport, S. M. Chenq, S. Dheer, C. Urbano, M. Levner, and P. P. Hung. "CONSTRUCTION AND EXPRESSION OF HYBRID PLASMINOGEN ACTIVATORS PREPARED FROM TISSUE-PLASMINOGEN ACTIVATOR (t-PA) AND UROKINASE (u-PA) GENES." In XIth International Congress on Thrombosis and Haemostasis. Schattauer GmbH, 1987. http://dx.doi.org/10.1055/s-0038-1643939.
Повний текст джерелаАнотація:
A covalent hybrid plasminogen activator was prepared from the sulfhydryl forms of the NH2-terminal A chain of human plasmin (Pln^) containing the fibrin-binding domain, and the COOH-terminal B chain of tissue plasminogen activator (t-PAB) containing the catalytic domain. The PlnA (SH)2 and t-PAB(SH) chains were mixed in a 1:1 molar ratio, and hybridization was allowed to proceed at 4 °C for 6 days. The covalent PlnA-t-PAB hybrid activator was isolated from the mixture by a two-step affinity chromatography method, with L-lysine-substituted Sepharose and Zn-chelated agarose. The protein yield of purified hybrid was 10% with a major component (77%) of Mr ∼92,000. The covalent PlnA-t-PAB hybrid activator, contained 1 mol of each chain; after reduction, it gave the two parent chains, PlnA and t-PAA, also shown to be present by double immunodiffusion. The specific plasminogen activator activity, with soluble fibrin, and the specific amidolytic activity, of the purified covalent hybrid activator was determined to be 200,000 IU/mg of protein, about 40% of the specific activity of the parent t-PA. In a fibrin clot lysis assay, the covalent hybrid activator and t-PA have similar specific fibrinolytic activities, 500,000 IU/mg of protein; however, the clot lysis time curves were not parallel. The binding of the covalent PlnA-t-PAB hybrid activator and t-PA to forming fibrin were found to be similar; at physiological fibrinogen concentrations, binding of both activators to forming fibrin was about 90%.