Literatura académica sobre el tema "Phosphate additives"
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Artículos de revistas sobre el tema "Phosphate additives"
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Anukam, Chinedu C. y Benedicta N. Agu. "Health implications of inorganic phosphate additives in food products: a systematic review". International Journal Of Community Medicine And Public Health 4, n.º 5 (24 de abril de 2017): 1445. http://dx.doi.org/10.18203/2394-6040.ijcmph20171496.
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Background: Evidence based data identifies phosphate additives in food products as a public health concern, especially in the progression of chronic kidney disease (CKD). However, there is limited public awareness of the risks associated with phosphate additives. This study focuses on a systematic review of findings on health implications of phosphate additives, with the aim of strengthening public health knowledge, insight, understanding and prevention of exposure to phosphate toxicity and chronic diseases.Methods: Studies with primary data on phosphate additives were identified using keyword electronic database search in PubMed and BMC. To meet the review criteria, articles needed to (1) be published in English (2) focus on phosphate additives (3) address the potential health risks associated with phosphate additives (4) identify existing health problems caused by phosphate additives (5) published between 2005 to 2017 to provide a more dynamic review and (6) hold a strong research evidence that confirms the associated risks of phosphate additives.Results: Findings from reviewed literature suggest a link between high phosphate content in food products and chronic renal failure, cardiovascular complications, accelerated aging process, allergic reactions and increased morality rate. The need to regulate the use of phosphates additives in food products and strengthen public health education is essential to minimise high exposure to phosphate additives.Conclusions: Further research, proper food labelling, strict regulation of unhealthy food additives, nutrition education and sensitisation of consumers are required to minimise exposure to phosphate additives and susceptibility to chronic diseases.
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Enax, Joachim, Frederic Meyer, Erik Schulze zur Wiesche y Matthias Epple. "On the Application of Calcium Phosphate Micro- and Nanoparticles as Food Additive". Nanomaterials 12, n.º 22 (19 de noviembre de 2022): 4075. http://dx.doi.org/10.3390/nano12224075.
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The human body needs calcium and phosphate as essential nutrients to grow bones and teeth, but they are also necessary for many other biochemical purposes (e.g., the biosynthesis of phospholipids, adenosine triphosphate, ATP, or DNA). The use of solid calcium phosphate in particle form as a food additive is reviewed and discussed in terms of bioavailability and its safety after ingestion. The fact that all calcium phosphates, such as hydroxyapatite and tricalcium phosphate, are soluble in the acidic environment of the stomach, regardless of the particle size or phase, means that they are present as dissolved ions after passing through the stomach. These dissolved ions cannot be distinguished from a mixture of calcium and phosphate ions that were ingested separately, e.g., from cheese or milk together with soft drinks or meat. Milk, including human breast milk, is a natural source of calcium and phosphate in which calcium phosphate is present as nanoscopic clusters (nanoparticles) inside casein (protein) micelles. It is concluded that calcium phosphates are generally safe as food additives, also in baby formula.
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Ioannidis, Themistoklis A. y Anastasios I. Zouboulis. "Hazardous industrial waste stabilization using inorganic phosphates: Investigation of possible mechanisms". Pure and Applied Chemistry 77, n.º 10 (1 de enero de 2005): 1737–52. http://dx.doi.org/10.1351/pac200577101737.
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The present study focuses on the use of phosphate-containing compounds, such as apatites, as stabilization additives for solid industrial wastes. The examined highly toxic waste contained mainly lead, iron, and bromides. Phosphates (synthetic or natural), when used as additives, were found to diminish the release of lead from the stabilized waste below the respective legislative concentration limits, following the application of DIN 38414 standard leaching method and within the range of pH values 7.5-10.5. The respective synthetic compounds of lead, PbO and Pb(OH)Br, existing also in the solid waste, were additionally studied during simulation experiments, in order to examine the possible mechanisms of waste stabilization, by using the same additives (phosphates). The obtained results showed the possibility of another parallel mechanism, different from that proposed in the literature, which is the sorption of aqueous lead ions onto the apatite surface. It was suggested that lead can be also transformed into the less soluble solid phases through the interaction (surface crystallization) of exposed lead surface with the aqueous environment. The formation of new crystals onto the surface of lead phase was sufficiently fast, especially in the case of natural phosphate mineral additive, most probably due to the presence of calcite, which supplies part of its carbonate content for the formation of respective lead carbonate solid phases.
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Rumyantseva, V., V. Konovalova y B. Narmaniya. "Modified phosphate coatings applied to steel by cold method". Journal of Physics: Conference Series 2131, n.º 4 (1 de diciembre de 2021): 042027. http://dx.doi.org/10.1088/1742-6596/2131/4/042027.
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Abstract The deposition of phosphate coatings occurs on the surface of the product when it is immersed in a solution containing phosphoric acid. The formation of a film on the metal surface occurs during the deposition of insoluble two- and three-substituted phosphates of iron, manganese, and zinc from a solution. To speed up the process and conduct phosphating at low temperatures, nitrates, nitrites, and fluorides of active metals are introduced into the solution. Organic compounds, such as glucose, glycerin, Trilon A, and Trilon B, are buffer additives to maintain the pH of phosphating solutions in the range of 2.6-3.2. It was found that 10-15 minutes at a process temperature of 20-25 °C are sufficient for the formation of a protective phosphate coating from solutions containing modifiers. The content of zinc phosphates in the modified phosphate coatings is increased. Additives in cold phosphating solutions have a positive effect on the quality and protective properties of the resulting phosphate films. Modified phosphate coatings obtained by the cold method have a fine-crystalline structure, a smooth surface and low porosity.
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Xia, Lu, You Shou Zhang y Jin Huang. "A New Compound Phosphate Heat-Cured Foundry Binder". Advanced Materials Research 97-101 (marzo de 2010): 979–82. http://dx.doi.org/10.4028/www.scientific.net/amr.97-101.979.
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Influences of additives on the physicochemical characteristics and technologies of binder are researched, and a new compound phosphate heat-cured foundry binder coded B8M15 is developed. The binder is made from environmental friendly inorganic materials such as phosphoric acid, aluminum hydroxide, B-ion additive and Mg-ion additive. Laboratory results indicate that combined effect of B-ion additive and Mg-ion additive can improve the storage stability of the binder and its sand mold or core, as well as they can increase the dry strength of its sand mold or core from 0.77MPa to 2.51MPa. This binder has low gas evolution and good collapsibility.
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Cardoso, H. A. I., M. Motisuke, A. C. D. Rodas, O. Z. Higa y Cecília A. C. Zavaglia. "PH Evolution and Cytotoxicity of [Alpha]-Tricalcium Phosphate Cement with Three Different Additives". Key Engineering Materials 493-494 (octubre de 2011): 403–8. http://dx.doi.org/10.4028/www.scientific.net/kem.493-494.403.
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An application of calcium phosphates is as bone cements, among which the system based on alpha-tricalcium phosphate (α-TCP) exhibits excellent properties. The aim of this study is to analyze pH evolution and cytotoxicity of α-TCP cement with three different additives. Changes on the pH were measured at intervals of 12h during seven days. But initial measurements were executed at each 15 minutes. Indirect cytotoxicity test was performed according to ISO (10993-5, 1992) employing CHO-k1 cells and RPMI 1640 as culture medium. It was used a colorimetric method which uses the tetrazolium compound. The additives used on the liquid phase were disodium hydrogen phosphate (Na2HPO4) and/or citric acid (C6H8O7) and/or tannic acid (C76H52O46). The results indicate that the cement without additives does not have requirements to be applied like bone cement, while the other cements composition exhibit different responses in the pH and the cytotoxicity test. In conclusion, due to the presence of additives it was possible to control pH evolution during setting and cytotoxic response. However, further investigation is necessary in order to determine the influence of these additives, mainly tannic acid, on the in vivo behavior of these bone cements.
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Rajasekharan, V. y P. Manisankar. "Polyaniline based red oxide primer paint for efficient corrosion protection". Anti-Corrosion Methods and Materials 61, n.º 6 (28 de octubre de 2014): 409–15. http://dx.doi.org/10.1108/acmm-07-2013-1283.
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Purpose – The purpose of this study is to introduce mechanochemically prepared polyaniline anticorrosive additives. In primer coating technology, there is an increasing interest in the development of efficient anticorrosive additives which replace the conventional inorganic anticorrosive pigments like heavy metal chromates and phosphates normally added to primer paints for the coating on metals. Conducting polymers are found to be better alternatives. Design/methodology/approach – Polyaniline phosphate is synthesized through solid-state conditions without using any solvent. The synthesized polyaniline phosphate is added in the primer formulation instead of zinc phosphate. Primers with different quantity of zinc phosphate are also formulated and studied for comparison. The comparison between their abilities to control corrosion of carbon steel were done with application of open-circuit potential monitoring, polarization and electrochemical impedance spectroscopy methods in 3.5 per cent NaCl solution. Findings – Corrosion studies indicate that polyaniline phosphate can improve corrosion protection properties by taking part the passivation processes. The performance of polyaniline phosphate is better than zinc phosphate. Originality/value – I certify that the results are from our original research and this paper is neither considered for publication elsewhere nor published previously.
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Mitrovic, Branislava, Gordana Vitorovic, Mirjana Stojanovic y Dusko Vitorovic. "Radioactivity of phosphate mineral products". Veterinarski glasnik 65, n.º 1-2 (2011): 133–40. http://dx.doi.org/10.2298/vetgl1102133m.
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The phosphate industry is one of the biggest polluters of the environment with uranium. Different products are derived after processing phosphoric ore, such as mineral and phosphate fertilizers and phosphate mineral supplements (dicalcium-and monocalcium phosphate) for animal feeding. Phosphate mineral additives used in animal food may contain a high activity of uranium. Research in this study should provide an answer to the extent in which phosphate mineral products (phosphate fertilizer and phosphate mineral feed additives) contribute to the contamination of soil, plants and animals.
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Kushchenko, P. O., V. V. Primachenko, I. G. Shulik y L. K. Savina. "Influence of a new dispersant additive amount on the structural and rheological properties of chamotte concrete and samples from it". Scientific research on refractories and technical ceramics 120 (30 de diciembre de 2020): 83–90. http://dx.doi.org/10.35857/2663-3566.120.07.
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The use of dispersing additives in the composition of concrete mixtures helps to reduce water demand, increase flow, increase strength after hardening in air. The effect of a new dispersant additive amount on a polycarbonate base in comparison with the currently used phosphate-containing additive on the structural and rheological properties of chamotte concrete from a mixture of the “SSHBD” grade and samples from it has been investigated. The optimal amount of new dispersant additive on the polycarbonate base has been established and it has been shown that, in its effect on the structural and rheological properties of concrete from a mixture of the “SSHBD” grade and the properties of samples from it, it is similar to the phosphate-containing additive used at present. The change nature of the concrete flowability is practically the same. "Vitality" (i.e. the time period during which the concrete mass is suitable for performing high-quality lining by vibrocasting) of the compared concretes is ~ 4 hours; cold crushing strength of concrete samples with additives after hardening in air for 7 days and heat treatment at a temperature of 110 °C, as well as cold crushing strength of samples after firing at a temperature of 1350 °C are practically the same. The use of new polycarbonate-based dispersant can be recommended for the preparation of chamotte concrete as an alternative phosphate-containing additive.
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Gebke, Stefan, Katrin Thümmler, Rodolphe Sonnier, Sören Tech, André Wagenführ y Steffen Fischer. "Flame Retardancy of Wood Fiber Materials Using Phosphorus-Modified Wheat Starch". Molecules 25, n.º 2 (14 de enero de 2020): 335. http://dx.doi.org/10.3390/molecules25020335.
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Biopolymer-based flame retardants (FR) are a promising approach to ensure adequate protection against fire while minimizing health and environmental risks. Only a few, however, are suitable for industrial purposes because of their poor flame retardancy, complex synthesis pathway, expensive cleaning procedures, and inappropriate application properties. In the present work, wheat starch was modified using a common phosphate/urea reaction system and tested as flame retardant additive for wood fibers. The results indicate that starch derivatives from phosphate/urea systems can reach fire protection efficiencies similar to those of commercial flame retardants currently used in the wood fiber industry. The functionalization leads to the incorporation of fire protective phosphates (up to 38 wt.%) and nitrogen groups (up to 8.3 wt.%). The lowest levels of burning in fire tests were measured with soluble additives at a phosphate content of 3.5 wt.%. Smoldering effects could be significantly reduced compared to unmodified wood fibers. The industrial processing of a starch-based flame retardant on wood insulating materials exhibits the fundamental applicability of flame retardants. These results demonstrate that starch modified from phosphate/urea-systems is a serious alternative to traditional flame retardants.
Tesis sobre el tema "Phosphate additives"
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Montazerolghaem, Maryam. "Additives Increasing the Bone-Forming Potential around Calcium Phosphate Cements : Statin, Strontium and Silicon". Doctoral thesis, Uppsala universitet, Tillämpad materialvetenskap, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-246289.
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More than one million people worldwide receive some kind of bone graft each year. Grafts are often needed following bone tumour removal or traumatic fractures to fill voids in the bone and to aid in the healing process. The most common method involves bone transplantation, in which bone tissue is taken from one site to fill the defect in another site. The procedure thus involves two surgeries, which leads to an increased risk of complications. New, synthetic graft materials that can be used to fill defects and minimise the complications associated with bone tissue harvesting are therefore necessary. The synthetic materials available today lack the inherent biological factors of bone that stimulate the bone regeneration process. Much of today’s research concerning synthetic bone graft materials aims to solve this issue and researchers have suggested several different strategies. The purpose of this thesis is to improve the performance of acidic calcium phosphate cements, which are materials used as synthetic bone grafts. By combining these cements with drugs or ion additives, local delivery could be achieved with the potential to stimulate bone formation. Two different combinations were attempted in this thesis: cement in combination with simvastatin, or cement in combination with strontium halide salts. Both simvastatin and strontium are known to positively affect bone formation. The efficacy of the cements with the additives was evaluated using different bone cell cultures. The results regarding simvastatin showed that the cement’s mechanical property was not affected upon drug loading, and that the drug was released by a diffusion-controlled mechanism. Moreover, results showed that simvastatin stimulated the bone-forming cells (osteoblasts) to produce more bone tissue, while it inhibited bone-degrading cells (osteoclasts) from degrading the cement. These findings suggest that simvastatin could aid in the bone regeneration process in the local area surrounding the cement. The main purpose of the study using strontium halide salts was to increase the cement’s X-ray contrast, which is a property used to monitor cement during injection. In addition, strontium is believed to positively affect bone cells. The X-ray contrast did increase after the addition of 10 wt% strontium bromide or strontium iodide, while the cell study results did not indicate any significant effects on the bone-forming cells. In the last section of this thesis, zebrafish were used as a model to evaluate bone formation upon treatment with degradation products from synthetic bone grafts. The zebrafish is a small organism with 70 % gene homology to humans; due to its transparency, fast development and ease of handling, it is an interesting model for high-throughput studies. Silicate, which is an ionic degradation product of many different bone substitute materials, was used as a proof-of-concept to visualise bone formation in these fish. The results showed an increased bone formation upon treatment with 0.625 μM silicate ions. The results suggest that this model could be used as a complement to bone cell culture studies in pre-clinical evaluations of the degradation products of bone substitute materials, thus helping researchers to design materials with degradation products that could stimulate bone formation.
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Cantaert, Bram. "Controlled crystallisation of calcium phosphate and calcium carbonate via bio-inspired approaches : additives and confinement". Thesis, University of Leeds, 2013. http://etheses.whiterose.ac.uk/4683/.
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This thesis describes the investigation of the two bio-inspired approaches, confinement and additives, to manipulate the crystallization of calcium carbonate and calcium phosphate. The first experimental chapter deals with the investigation of calcium phosphate rods grown in confined environments in the absence and presence of polyaspartic acid. Although similar results were obtained in the absence and presence of the additive, growing calcium phosphate in confinement allowed formation of polycrystalline rods with an orientation comparable to bone. This demonstrated that confinement may play a more significant role in bone formation than previously anticipated. The second chapter deals with the effect of positively charged additives on the crystallisation of CaCO3. Although neglected before in literature, this chapter demonstrates that positively charged additives have a profound effect on the crystallisation of CaCO3 changing the morphology to films and fibers. This morphology change was linked to a phase separation process, forming hydrated amorphous droplets of calcium carbonate by a carbonate-polymer interaction, which had the tendency to coalesce and form films. Fiber formation was attributed to oriented attachment of anisotropic particles due to unequal distribution of charge. In the third chapter, based on bone, the mineralisation of collagen by CaCO3 was investigated. By formation of a highly hydrated liquid-like amorphous phase of CaCO3, it was possible to infiltrate the nanoscale gaps of collagen. After crystallisation, nanocrystals of calcite and vaterite were formed, 5 nm thick, but randomly oriented, demonstrating collagen templates the shape but not the orientation of the crystals. In a final chapter hollow rods of CaCO3 were formed by templating them inside membrane pores. The influence of time, pore size, additives and surface chemistry was investigated. Most hollow rods were formed at early timescales which filled up at later times. By changing the surface chemistry, the amount of hollow rods increased significantly in the 200 nm pores
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Bhatt, Himesh A. "Synthesis and Characterization of Nanocrystalline Hydroxyapatite Powder; And the Effects of Oxide-Based Sintering Additives on Tricalcium Phosphate". Master's thesis, University of Central Florida, 2005. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/3567.
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Calcium phosphate (CP) materials have been used extensively for bone replacement and augmentation due to their similarity to the mineral component of bone. In addition to being non-toxic, they are biocompatible, not recognized as foreign materials in vivo, and most importantly, exhibit osteoconductive behavior, being able to help in bone formation during healing. CPs form an intimate physicochemical bond with the host tissue, termed osseointegration. However the main limitation of calcium phosphates is their inherent brittle nature and poor mechanical performance under complex stress states. As a result, these materials have been used clinically only in non-load-bearing applications, primarily as granules. The primary goal of this research was to enhance mechanical performance of CPs, tricalcium phosphate (TCP) and hydroxyapatite (HAp) to be precise, in an attempt to develop controlled strength-loss resorbable/ bioactive ceramic bone-grafts for hard tissue engineering. In my work on TCP, I selected and introduced small quantities of single and multi-oxide sintering additives in TCP, to study their influence on sintering behavior, densification, mechanical properties and biodegradation/ biomechanical properties in vitro. Through this research, I could improve mechanical performance of [Beta]-tricalcium phosphate ([beta]-TCP) and controlled its rate of biodegradation by introducing of certain additives. In my second work, I improved mechanical performance of HAp (Ca10(PO4)6(OH)2 by reducing particle-size of the powder through the synthesis of stoichiometric, nanocrystalline, single phase HAp powder in the range of 2-20 nm. Synthesis of powder was accomplished via a modified low temperature sol-gel technique using ethanol/ water as solvent.M.S.M.S.E.
Department of Mechanical, Materials and Aerospace Engineering;
Engineering and Computer Science
Materials Science and Engineering
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Philippon, David. "Lubrification par la phase gazeuse : tribochimie des additifs phosphorés et boratés". Phd thesis, Ecole Centrale de Lyon, 2007. http://tel.archives-ouvertes.fr/tel-00280892.
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La formulation des lubrifiants utilisés dans l'automobile est complexe du fait du nombre important d'additifs mélangés aux huiles de base. Pour orienter le choix des formulateurs, il est non seulement nécessaire de connaître le mécanisme d'action de chaque additif mais aussi les interactions entre ces additifs. Pour mieux appréhender ces mécanismes, une démarche originale a été mise en place dans cette étude. Celle-ci consiste à simuler expérimentalement la lubrification en régime limite par la lubrification en phase gazeuse. Pour cela, des molécules de faible poids moléculaire modélisant les différents constituants d'un lubrifiant ont été introduites sous ultravide. Ce type d'expérience a pu être réalisé grâce au développement d'un nouveau Tribomètre à Environnement Contrôlé (TEC) connecté à un système d'analyse de surface. Cette technique permet de simplifier le système tribologique et d'étudier in situ les tribofilms formés en phase gazeuse par des analyses de surface (XPS/AES). Différentes molécules ont été étudiées : triméthylborate (TMB), triméthylphosphite (TMPi) et triméthylphosphate (TMPa) modélisant respectivement les additifs boratés et phosphorés des lubrifiants de transmission. Cette simulation expérimentale a pu être validée en comparant les résultats en phase gazeuse avec ceux obtenus en phase liquide. Des observations en microscopie optique et des analyses chimiques ont mis en évidence la formation de tribofilms. Les expériences réalisées en présence de TMB ont permis de confirmer les résultats de la littérature sur la formation d'un tribofilm non sacrificiel de borates de type « minéral ». Les expériences réalisées avec les molécules phosphorées ont permis de montrer la différence entre les phosphates et les phosphites, notamment la formation d'un composé de type phosphure de fer en présence de TMPi. Les analyses in situ sur les tribofilms obtenus en présence de TMPi ont permis de déterminer le mécanisme de formation du composé phosphure de fer. La réalisation de mélanges de gaz a permis également de mettre en avant les effets de synergie et d'antagonisme entre les additifs
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Barnett, G. M. (Gordon M. ). "Feed additives and animal waste phosphorous reactions". Thesis, McGill University, 1992. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=41322.
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Organic phosphorus (P$ sb{ rm o}$) in farm animal wastes must be mineralized to inorganic P for subsequent plant use. This study was conducted to determine if feed additives affect P$ sb{ rm o}$ mineralization, manure decomposition, and plant growth. Feed additives in aqueous systems affected the P mineralization of inositol hexaphosphate by phytase and of adenosine monophosphate by alkaline phosphatase. Pronounced effects were produced by bacitracin and both enzymes and by neomycin on phytase. Feed additives in dairy cattle (Bos taurus L.) manure produced effects on microbial activity as measured by gas production that differed from those produced on fecal phosphatase activity. Additives applied directly or with manure to Ste. Rosalie clay, Greensboro loam, or silica sand had no effect on barley (Hordeum vulgare L.) yield but did produce additive, rate, growth medium, and manure dependent effects on plant P concentration and soil phosphatase activity. Therefore, each feed additive must be independently evaluated to determine its effect on biological systems.
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Ramalho, Eduardo Galv?o. "Obten??o de cer?micas ? base de tric?lcio fosfatos utilizando ?xido de mangan?s como aditivo". Universidade Federal do Rio Grande do Norte, 2006. http://repositorio.ufrn.br:8080/jspui/handle/123456789/15544.
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The calcium phosphate ceramics have been very investigated as material for bone implants. The tricalcium phosphate (β-TCP) had a great potential for application in temporary implants like a resorbable bioceramic. This material presents a limitation in its sintering temperature due to occurrence of the allotropic transformation β → α at temperatures around 1200?C, not allowing the attainment of dense ceramic bodies. This transformation also causes cracks, what diminishes the mechanical strength, limiting its use to applications of low mechanical requests. This work studies the influence of the addition of manganese oxide in the sintering of β-TCP. Two processing routes were investigated. The first was the powder metallurgy conventional process. The test bodies (samples) were pressed and sintering at temperatures of 1200 and 1250?C. The second route was uniaxial hot pressing and its objective was to obtain samples with high relative density. The samples were physically characterized through density and porosity measurements. The thermal behavior was studied through dilatometric, thermal differential and thermogravimetric analysis. The mechanical properties were characterized by three point flexure test and Vickers microhardness measurements. The microstructure was analyzed by scanning electron microscopy. The addition of manganese oxide caused an improvement of the mechanical strength in relation to the material without additive and promoting the stabilization of β-TCP to greater temperatures
As cer?micas de fosfato de c?lcio t?m sido intensamente investigadas como materiais para implantes ?sseos. O fosfato tric?lcico (β-TCP) possui um grande potencial para aplica??o em implantes tempor?rios por ser uma biocer?mica absorv?vel. Entretanto, este tipo de material apresenta uma limita??o na sua temperatura de sinteriza??o devido ? ocorr?ncia da transforma??o alotr?pica β → α em torno de 1200?C. Isto impede a obten??o de corpos cer?micos densos e provoca trincas, diminuindo a resist?ncia do material e limitando a sua utiliza??o a aplica??es de baixa solicita??o mec?nica. A influ?ncia da adi??o de ?xido de mangan?s na sinteriza??o do β-TCP foi estudada neste trabalho. Duas rotas de processamento foram investigadas. A primeira utilizou o processo convencional de metalurgia do p?. Os corpos de prova foram prensados, sendo posteriormente sinterizados nas temperaturas de 1200 e 1250?C. O segundo m?todo de processamento utilizou a rota de prensagem uniaxial a quente, e tinha como objetivo obter corpos de prova com alta densidade relativa. As amostras foram caracterizadas fisicamente por meio de medidas de porosidade e densidade e termicamente por dilatometria e an?lise termogravim?trica e t?rmica diferencial. Os corpos sinterizados foram caracterizados mecanicamente por resist?ncia a flex?o em 3 pontos e microdureza Vickers, sendo tamb?m sua microestrutura analisada por microscopia eletr?nica de varredura. A adi??o do ?xido de mangan?s ocasionou uma melhoria da resist?ncia mec?nica em rela??o ao material sem aditivo, al?m de promover uma estabiliza??o do β-TCP em temperaturas mais elevadas
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Shallcross, Laura. "Investigating the interactions of nanoscale calcium phosphates with polymer additives". Thesis, University of Sheffield, 2017. http://etheses.whiterose.ac.uk/16902/.
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Mambingo, Doumbe Samuel. "Simulation de la phase gazeuse des réactions tribochimiques des additifs phosphorés et soufrés". Thesis, Ecully, Ecole centrale de Lyon, 2012. http://www.theses.fr/2012ECDL0063.
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La maîtrise de l’additivation est l’un des enjeux majeurs de la formulation des lubrifiants, notamment pour l’industrie automobile. La formulation d’une huile est toutefois très complexe en raison du nombre important d’additifs et des nombreuses interactions possibles entre additifs, notamment entre les additifs de surface. Les phosphites organiques et les polysulfures organiques ont déjà montré leur efficacité en tant qu’additifs de surface. Toutefois malgré leur usage répandu dans les formulations des lubrifiants automobiles, peu d’études traitent des interactions pouvant avoir lieu entre ces deux types de composés. Ce travail de thèse a pour objectif la compréhension des mécanismes d’interaction (antagonisme/synergie) pouvant exister entre les phosphites organiques et les polysulfures organiques. Pour cela, une approche originale sur la lubrification par la phase gazeuse s’est avérée très pertinente. Le couplage du Tribomètre à Environnement Contrôlé (TEC) avec les systèmes d’analyses de surface XPS/Auger a permis d’analyser les tribofilms générés in situ et d’éviter ainsi toute contamination et/ou oxydation du tribofilm avant analyse. Les molécules choisies sont les additifs de lubrification industriels (polysulfures tertaires) à faibles poids moléculaires ou alors des molécules à faible poids moléculaires ayant les mêmes fonctions chimiques que les additifs usuels : trimethyl phosphite (TMPi), dimethyl phosphite (DMPi). L’étude des réactions des tribochimiques des molécules phosphorés a permis de mettre en évidence le rôle ambivalent du DMPi qui se comporte à la fois comme un phosphite pour former un phosphure de fer et comme un phosphate. Le mécanisme formation du phosphure de fer a peu être étayé par la réalisation de calculs ab initio sur l’adsorption dissociative du TMPi sur une surface de fer. Les TPS étudiés génèrent quant à eux des tribofilms à base disulfure de fer. Les mélanges binaires réalisés en phase gazeuse ont permis de mettre en évidence l’importance des rapports de concentrations des vapeurs introduites et du mode d’introduction des molécules dans le tribomètre. Les résultats obtenus en tribologie en phase gazeuse ont été corroborés par des essais complémentaires en phase liquideMastering the addivation is one of the biggest issues for the lubricants formulation, especially in the automobile industry. However automotive lubricants are very complex systems due to the numerous additives mixed with base oils. Many interactions can occur between additives, especially between surface additives. Organic phosphites and organic polysulphides have already demonstrated their effectiveness as surface additives. However, despite their widespread use in the formulations of automotive lubricants, few studies deal with the interactions taking place between these two types of compounds. The aim of this study is to understand the interactions, antagonistic or synergetic effect between these kinds of additives using Gas Phase Lubrication (GPL) approach. A Environmental Controlled Tribometer (TEC) was used as a tool to simulate the interaction between organophosphate additives and polysulfurous additives. In situ surface analysis was performed in the tribofilm formed during friction using of X-ray Photoelectron Spectroscopy (XPS) and Auger Electron Spectroscopy(AES) in order to avoid any oxidation or air contamination. The molecules selected for the study can be same as the additive like the TPS molecules which are widely used as lubricant additives. Howeverto simulate the phosphite chemical function of phosphite additives, we need to select smaller molecule having the same chemical function. These molecules are dimethyl phosphite (DMPi), trimethylphosphate (TMPi) for simulating the phosphite chemical function and organic polysulphides (TPS44and TPS32). The study of the tribochemical reactions of organic phopshites allowed to clearly characterise the ambivalence of DMPi, which can react like a phosphite and induce iron phosphide formation or react like a phosphate. Ab initio numerical simulation on TMPi dissociative adsorption was carried out to identify the reactions pathways leading to iron phosphide formation. The tribochemical reaction of TPS44 on metallic iron surface leads to the formation of iron disulphidebased tribofilm. The binary vapours mixtures studied by GPL allowed to clearly identify the importance of the vapour concentration ratio between phosphite and polysulphide. Liquid phase experiments were also carried out to confirm the trend observed in GPL approach
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Armstrong, Kenneth Mark. "Catalytic synthesis of organophosphate plastics additives from white phosphorus". Thesis, University of St Andrews, 2011. http://hdl.handle.net/10023/2587.
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Triaryl phosphates were synthesized from white phosphorus and phenols in aerobic conditions and in the presence of iron catalysts and iodine. Full conversion to phosphates was achieved without the use of chlorine or chlorinated solvents, and the reactions do not produce acid waste. Triphenyl phosphate, tritolyl phosphate and tris(2,4-di-tert-butyl)phenyl phosphate were synthesized by this method with 100% conversion from P₄. Various iron(III) diketonates were used to catalyse the conversion. Mechanistic studies showed the reaction to proceed via the formation of phosphorus triiodide (PI₃), then diphenyl phosphoroiodidate (O=PI(OPh)₂) before the final formation of triphenyl phosphate (O=P(OPh)₃). The nucleophilic substitution of O=PI(OPh)₂ with phenol to form O=P(OPh)₃ was found to be the rate determining step. It was found that by modifying the reaction conditions the same catalytic systems could be used to synthesize triphenyl phosphite directly from P₄. Triphenyl phosphite was synthesized in selectivities of up to 60 %. The mechanism of these transformations was also elucidated. Independent syntheses of the intermediate in the reaction mechanism, O=P(OPh)₂I and its hydrolysis products diphenyl phosphate (O=P(OPh)₂OH) and tetraphenyl pyrophosphate ((O)P(OPh)₂-O-P(O)(OPh)₂) were developed from PI₃. The 2,4-di-tert-butyl phenol analogues of these compounds were also prepared. Bis-(2,4-di-tert-butylphenyl) phosphoroiodidate was then reacted with various alcohols to produce a series of mixed triorgano phosphates.
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Bissessar, Damien. "Synthèse de nouveaux composés phosphorés : vers de nouveaux additifs pour polymères et des complexes cuivreux luminescents innovants". Thesis, Strasbourg, 2018. http://www.theses.fr/2018STRAE029.
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Ce travail de thèse s’est inscrit dans le cadre d’un projet en relation étroite avec une industrie chimique. La problématique initiale concerne le développement de nouvelles molécules antioxydantes permettant de protéger les matériaux plastiques. Dans un premier temps, la stratégie envisagée s’appuie sur la synthèse de phosphines par hydrophosphination, réaction répondant aux principes de la chimie verte. La réaction est hautement régiosélective et la simplicité de la synthèse a permis d’obtenir de nombreuses nouvelles phosphines qui ont alors été testées pour leurs propriétés anti-oxydantes. Nous avons pu identifier plusieurs structures originales répondant au cahier des charges. Dans un second temps, nous avons étudié la faisabilité de développer de nouveaux additifs antioxydants secondaires à base de dérivés phénoliques, dont le cardanol qui est une molécule biosourcée. De nombreuses nouvelles molécules phosphorées ont été synthétisées, complètement caractérisées et évaluées pour leurs propriétés anti-oxydantes. Enfin, nous avons essayé de valoriser nos nouveaux composés pour d’autres applications. Les phosphines étant d’excellents ligands pour les métaux de transition, nous avons étudié la chimie de coordination avec le cuivre(I) en espérant former des complexes cuivreux luminescents. En effet, l’élaboration de diodes électroluminescentes stables reste un défi technologique malgré toutes les avancées actuelles. Dans ce contexte, de nombreux nouveaux complexes de type cubane ont été synthétisés et entièrement caractérisés. Ces complexes tétranucléaires sont des structures intéressantes, faciles à synthétiser, avec d’excellents rendements quantiques. Ces complexes présentent une stabilité élevée et des propriétés de luminescence qui en font de très bons candidats pour des dispositifs en optoélectroniqueThis thesis work was part of a project in collaboration with a chemical industry. The topic is the development of new antioxidant molecules to protect plastic materials. Initially, the strategy envisaged was based on the synthesis of phosphines by hydrophosphination, reaction in accordance with the green chemistry principles. The reaction is highly regioselective and the simplicity of the synthesis allowed us to obtain many new phosphines which were then tested for their antioxidant properties. We were able to identify several original structures that meet the requirements. In a second step, we studied the feasibility of developing new secondary antioxidant additives based on phenolic derivatives, including cardanol, which is a biosourced molecule. Many new phosphorus molecules have been synthesized, completely characterized and evaluated for their antioxidant properties. Finally, we tried to apply our new compounds for other applications. Since phosphines are excellent ligands for transition metals, we studied coordination chemistry with copper (I), hoping to form luminescent copper complexes. Indeed, the development of stable light-emitting diodes remains a technological challenge despite all the current advances. In this context, many new cubane-type complexes have been synthesized and fully characterized. These tetranuclear complexes are interesting structures, easy to synthesize, with excellent quantum yields. These complexes exhibit high stability and luminescence properties, which make them very good candidates for optoelectronic devices
Libros sobre el tema "Phosphate additives"
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John, Ferrante, Honecy Frank S y United States. National Aeronautics and Space Administration., eds. The effect of tricresyl-phosphate (TCP) as an additive on wear of iron (Fe). [Washington, DC]: National Aeronautics and Space Administration, 1987.
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John, Ferrante, Honecy Frank S y United States. National Aeronautics and Space Administration., eds. The effect of tricresyl-phosphate (TCP) as an additive on wear of iron (Fe). [Washington, DC]: National Aeronautics and Space Administration, 1987.
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John, Ferrante, Honecy Frank S y United States. National Aeronautics and Space Administration., eds. The effect of tricresyl-phosphate (TCP) as an additive on wear of iron (Fe). [Washington, DC]: National Aeronautics and Space Administration, 1987.
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United States. National Aeronautics and Space Administration., ed. Phospha-s-triazines and related compositions of improved hydrolytic and thermal stability. [Washington, DC: National Aeronautics and Space Administration, 1996.
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United States. National Aeronautics and Space Administration., ed. Phospha-s-triazines and related compositions of improved hydrolytic and thermal stability. [Washington, DC: National Aeronautics and Space Administration, 1996.
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United States. National Aeronautics and Space Administration., ed. Phospha-s-triazines and related compositions of improved hydrolytic and thermal stability. [Washington, DC: National Aeronautics and Space Administration, 1996.
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Phosphates As Food Ingredients. Taylor & Francis Group, 2017.
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Ellinger, R. H. Phosphates As Food Ingredients. Taylor & Francis Group, 2018.
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Ellinger, R. H. Phosphates As Food Ingredients. Taylor & Francis Group, 2018.
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Ellinger, R. H. Phosphates As Food Ingredients. Taylor & Francis Group, 2018.
Buscar texto completoCapítulos de libros sobre el tema "Phosphate additives"
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Üstün, Fatma, Hasan Demir y Devrim Balköse. "Flame Retardant and Smoke Suppressant Additives for Polypropylene: Vermiculite and Zinc Phosphate". En Research Methods and Applications in Chemical and Biological Engineering, 59–82. Series statement: AAP research notes on chemical engineering: Apple Academic Press, 2019. http://dx.doi.org/10.1201/9780429424137-6.
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Sallis, John D. "Structure/Performance Relationships of Phosphorous and Carboxyl Containing Additives as Calcium Phosphate Crystal Growth Inhibitors". En Calcium Phosphates in Biological and Industrial Systems, 173–91. Boston, MA: Springer US, 1998. http://dx.doi.org/10.1007/978-1-4615-5517-9_8.
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Mills, David K. "The Role of Polymer Additives in Enhancing the Response of Calcium Phosphate Cement". En Orthopedic Biomaterials, 345–79. Cham: Springer International Publishing, 2018. http://dx.doi.org/10.1007/978-3-319-89542-0_14.
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Wolff, D. M. B., E. G. Ramalho y Wilson Acchar. "Phase Transition Behaviour of Tricalcium Phosphate (TCP) Doped with MgO and TiO2 as Additives". En Materials Science Forum, 581–86. Stafa: Trans Tech Publications Ltd., 2006. http://dx.doi.org/10.4028/0-87849-423-5.581.
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Aravindan, S., A. Nishara Begum y R. Uthrakumar. "Additive-Based Structure and Bioactivity Modifications of Phosphate Glasses". En Materials Horizons: From Nature to Nanomaterials, 67–87. Singapore: Springer Nature Singapore, 2022. http://dx.doi.org/10.1007/978-981-19-2639-6_4.
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Juvancz, Z., K. E. Markides y L. Jicsinszky. "Perspectives of Chiral Capillary Electrophoresis Using Phosphated Cyclodextrins as Additives". En Proceedings of the Eighth International Symposium on Cyclodextrins, 649–52. Dordrecht: Springer Netherlands, 1996. http://dx.doi.org/10.1007/978-94-011-5448-2_140.
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Clelia Righi, M. "Understanding the Tribochemistry of Lubricant Additives by Ab initio Calculations: The Case of Phosphites". En Microtechnology and MEMS, 309–23. Cham: Springer International Publishing, 2018. http://dx.doi.org/10.1007/978-3-319-99897-8_12.
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Saat, Asmalina Mohamed, Syarmela Alaauldin, Asmawi Malik, Md Salim Kamil y Abdul Latiff Mohd Zaini. "Hybrid Composite Fiberglass Structure with Embedded Aluminum Phosphate New Fire Retardants Additive: Effect of Fiberglass Types". En Advanced Engineering for Processes and Technologies II, 31–40. Cham: Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-67307-9_4.
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Bennett, James P., Brent W. Riggs, Kyei Sing Kwong y Jinichiro Nakano. "Mechanisms of Wear Reduction in High Chrome Oxide Refractories Containing Phosphate Additions Exposed to Coal Slag". En Proceedings of the Unified International Technical Conference on Refractories (UNITECR 2013), 1197–204. Hoboken, NJ, USA: John Wiley & Sons, Inc., 2014. http://dx.doi.org/10.1002/9781118837009.ch203.
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"Calcium Phosphate Dibasic". En Food Additives Data Book, 622–23. Oxford, UK: Blackwell Science Ltd, 2007. http://dx.doi.org/10.1002/9780470995327.ch216.
Texto completoActas de conferencias sobre el tema "Phosphate additives"
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Sappok, Alexander, Sean Munnis y Victor W. Wong. "Individual and Synergistic Effects of Lubricant Additive Components on Diesel Particulate Filter Ash Accumulation and Performance". En ASME 2012 Internal Combustion Engine Division Spring Technical Conference. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/ices2012-81237.
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The current CJ-4 oil specification places a limit on the oil’s sulfated ash content of 1.0% to reduce the build-up of lubricant-derived ash in the diesel particulate filter (DPF). Lubricant additives, specifically detergents and anti-wear additives, contribute to most of the sulfated ash content in the oil and ash accumulation in the DPF, and hence are studied with increasing interest in the optimization of the combined engine-oil-aftertreatment system. However, characteristics of ash deposits found in the particulate filter, which are affected by a number of parameters, differ markedly from those of the ASTM-method defined sulfated ash. In addition, ash characteristics and effects on DPF performance vary substantially among the different metallic base in the additives, specifically calcium, magnesium, and zinc. Through a series of carefully-controlled tests with specially-formulated lubricant additives, this work quantified the individual and combined effects of the most common detergent and anti-wear additives on the ash properties which directly influence DPF pressure drop. The results show that different lubricant additive formulations (Ca, Zn, Mg) produce profound differences in DPF pressure drop. It was found that DPF ash is a complex mixture of metals (Ca, Zn, Mg) in the form of sulfates, phosphates, and oxides. These ash compounds each have unique physical properties, which affect DPF pressure drop differently. In particular, ash containing calcium sulfate compounds resulted in an increase in filter pressure drop by over a factor of two, relative to the same amount of ash composed only of zinc phosphate or magnesium oxide compounds, at the same ash loading in the DPF. In addition, synergistic effects due to specific additive combinations were also explored and showed significant differences in ash composition and degree of exhaust flow restriction imposed by the ash resulting from specific additive combinations, as opposed to the individual additives themselves. Results are useful not only for lubricant formulators to design oils for improved aftertreatment system compatibility, but also to understand the practical effects of ash in the DPF in relation to the standardized sulfated ash definition in the lubricant specification.
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Konovalova, V. S. "Obtaining Luminous Phosphate Coatings on Steel by Cold Method". En Modern Trends in Manufacturing Technologies and Equipment. Materials Research Forum LLC, 2022. http://dx.doi.org/10.21741/9781644901755-12.
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Abstract. The possibility of obtaining luminous phosphate coatings on steel by cold method has been studied. Modified cold phosphating solutions containing organic additives (glycerin, trilon B, OS-20 emulsifier) were selected as the basis to maintain the pH, stabilize the solution and improve the quality and structure of the deposited coatings. To obtain the glow effect, a green phosphor based on Zn2SiO4 containing manganese as a sensitizer was added to the phosphating solution. During deposition, phosphate coatings are obtained that glow with spots, but constant mixing of the solution during deposition contributes to the uniform distribution of phosphor in the phosphate film. Luminous phosphate coatings have good protective properties, they can be used as an independent protection of steel surfaces from corrosion.
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Trubachev, S. A., O. P. Korobeinichev, V. D. Kobtsev, D. N. Kozlov, S. A. Kostritsa, V. V. Smirnov, S. Yu Volkov y Amit Kumar. "SPECIFIC FEATURES OF POLYMETHYL METHACRYLATE COMBUSTION WITH AND WITHOUT TRIPHENYL PHOSPHATE ADDITIVES: INVESTIGATION BY LASER-INDUCED FLUORESCENCE AND COHERENT ANTI-STOKES RAMAN SPECTROSCOPY". En 9TH INTERNATIONAL SYMPOSIUM ON NONEQUILIBRIUM PROCESSES, PLASMA, COMBUSTION, AND ATMOSPHERIC PHENOMENA. TORUS PRESS, 2020. http://dx.doi.org/10.30826/nepcap9a-24.
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The influence of triphenyl phosphate additives on the characteristics of flame propagation along a polymethyl methacrylate (PMMA) sample has been shown by laser-induced fluorescence and coherent anti-Stokes light scattering spectroscopy.
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Philippon, D., M. I. De Barros, Th Le Mogne, J. M. Martin y M. Kasrai. "Friction-Induced Change of Boron Hybridization in Lubricant Additives". En World Tribology Congress III. ASMEDC, 2005. http://dx.doi.org/10.1115/wtc2005-64188.
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Tribochemical interactions between antiwear zinc dithiophosphate (Zndtp), friction modifier molybdenum dithiocarbamate (Modtc) and overbased detergent calcium borate (OCB) lubricant additives have been investigated. A Cameron-Plint friction machine was used to generate large tribofilm areas in mild tribological conditions. Two analytical techniques, X-ray photoelectron spectroscopy (XPS) and X-ray absorption near edge structure spectroscopy (XANES), have been employed to characterize the chemical species in tribofilms. XANES spectroscopy at the P K and L-edges, S K-edge, Mo L and M-edges and B K-edge was carried out in order to investigate phosphate, sulfide and borate species in tribofilms. The XANES spectra were recorded in both the total electron yield (TEY), surface sensitive and fluorescent yield (FY), bulk sensitive mode. This was completed with XPS analyses in the same location in the tribofilm. The ternary system Zndtp + Modtc + OCB provides a low wear rate comparable to the binary system Modtc + OCB. XANES analyses have shown that adding OCB to the binary system Zndtp + Modtc increases the formation of MoS2 and reduce the formation of ZnS. It has been seen that few quantity of boron is consumed during the tests, meaning that boron does not react with other additives, we only observe a formation of calcium phosphate. A special attention has been paid on the hybridization of boron (trigonal sp2 and tetrahedral sp3). All tribofilms show a higher proportion of trigonal borate than the additives alone. However, this proportion is the highest in the case of tribofilms produce with the ternary mixture OCB + Zndtp + Modtc. Borate has a planar conformation and could be friction-oriented in the sliding interface. The oriented borate planar molecule might be at the origin of the MoS2 sheets orientation in the ternary system.
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Spencer, N. D., R. Heuberger, J. Antifakos y A. Rossi. "The Role of Temperature and Substrate Pairing in the Tribochemistry of Phosphorus-Based Additives". En World Tribology Congress III. ASMEDC, 2005. http://dx.doi.org/10.1115/wtc2005-64290.
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The tribochemical mechanism of phosphorus-containing additives is important to understand, even if the ultimate aim is to replace them with something more environmentally benign. In a combinatorial experiment that explored a range of temperatures (RT-180°C), loads, two additives, and two substrate pairings, it was observed that zinc dialkyldithiophosphate (ZnDTP) reacted with steel surfaces to produce phosphate at room temperature, pyrophosphate at 130°C, and polyphosphate at 180°C. Metal-ceramic pairings did not seem to produce long-chain polyphosphates at 150°C. It was also observed that metal-metal pairings appear to benefit more from the presence of the additives than ceramic-metal pairings, which suggests that the role of the additives is largely to inhibit microwelding of the asperities across the sliding plane.
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Komvopoulos, K., V. Do, E. S. Yamaguchi y P. R. Ryason. "Nanomechanical and Nanotribological Properties of an Antiwear Tribofilm Produced From Phosphorus-Containing Additives on Boundary-Lubricated Steel Surfaces". En ASME/STLE 2004 International Joint Tribology Conference. ASMEDC, 2004. http://dx.doi.org/10.1115/trib2004-64284.
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Nanoindentation and nanotribological experiments were performed on an antiwear tribofilm produced from a blend consisting of gear base oil and phosphorus-containing additive. Electrical contact resistance measurements were used to determine in situ the formation of the tribofilm on AISI steel surfaces at 100 °C under conditions favoring sliding in the boundary lubrication regime. Nanoindentation experiments were carried out with a surface force microscope on a small sector of a disk specimen that contained part of the wear track. A Berkovich diamond tip with a nominal radius of curvature equal to 100 mm was used to perform indentations on and off the wear track under a normal load between 100 and 600 μN. The phosphate tribofilm exhibited an average hardness of 6.0 GPa and reduced elastic modulus of 122.7 GPa compared to 12.5 GPa and 217.6 GPa of the steel substrate, respectively. In addition to the nanomechanical properties, the nanotribological properties of the tribofilm were evaluated in light of nanofriction tests performed with a 20 μm radius of curvature conical diamond tip under a normal load in the range of 100–200 μN. The original steel surfaces exhibited constant friction, whereas the wear track covered by the phosphate tribofilm, whereas the wear track covered by the phosphate tribofilm revealed a higher and more fluctuating coefficient of friction, which is attributed to the roughness of the wear track and the greater plasticity of the tribofilm than the substrate.
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Tysoe, Wilfred T. "Understanding the Tribological Chemistry of Chlorine- and Sulfur- and Phosphorus-Containing Additives". En World Tribology Congress III. ASMEDC, 2005. http://dx.doi.org/10.1115/wtc2005-63361.
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Chlorine- and sulfur- and phosphorus-containing compounds are commonly added to the base fluid to synthesize lubricants used under extreme-pressure (EP) conditions. Analyzing the resulting tribological films on iron reveals that chlorinated hydrocarbons thermally decompose forming a layer that consists of iron chloride (FeCl2) or carbide (Fe3C), and that dialkyldisulfides react to form FeS and Fe3C. Alkyl phosphates thermally decompose on iron oxide to form alkyl and alkoxy, as well as POx species, on the surface. The alkyl and alkoxy species thermally decompose on heating to evolve gas-phase products and deposit carbon onto the surface. The POx species rapidly diffuse into the oxide forming a film that consists of a carbonaceous layer covering a phosphate film. The tribological properties of evaporated and reactively grown thin films have been investigated in ultrahigh vacuum. This strategy eliminates contamination and allows films of known composition and structure to be grown on well-characterized substrates. Three tribological regimes are identified depending on film thickness. In the first regime, an initial rapid decrease in friction is found when a film that is a few nanometers thick (corresponding to a monolayer) covers the surface. The friction coefficient increases once again in the second regime as the film becomes thicker, due to the increased contact area between the film and the rough tribotip, and the behavior is well described by a modified Greenwood-Williamson model. A third regime is found when the film becomes thicker than the interfacial roughness, where the surfaces are completely separated by the film. Finally, measuring the friction coefficients of thin halide films deposited onto various substrates, where the local pressure at the asperity tips depends on the substrate hardness, shows that the shear strength of the “monolayer” films depends on pressure.
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Zaki, Tarek G. "Containment Sump Neutralization Using Trisodium Phosphate: Parametric Analysis". En 10th International Conference on Nuclear Engineering. ASMEDC, 2002. http://dx.doi.org/10.1115/icone10-22111.
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For post-LOCA conditions, the pH of the aqueous solution collected in the containment sump after completion of injection of containment spray and ECC water, and all additives for reactivity control, fission product removal, and other purposes, should be maintained at a level sufficiently high to provide assurance that significant long-term iodine re-evolution does not occur. Long-term iodine retention may be assumed only when the equilibrium sump solution pH is above 7. This pH value should be achieved by the onset of the spray recirculation mode. A trisodium phosphate (TSP)-based, passive system can be used to achieve this pH value. This is a proven technology that is already in use in nuclear power plants. This system consists of several wire mesh baskets, filled with TSP and strategically located in the sump in order to insure timely dissolution of TSP and rapid pH rise under LOCA conditions. Accurate determination of the total quantity of TSP required to raise the pH of borated water in the sump to within the acceptable range is the key element to a proper design of this system. However, this type of analysis is quite involved and highly iterative, which requires the use of a computer program. This paper describes the basis for a computer program that determines the required quantity of TSP as a function of the quantity of borated water in the sump, the boron concentration, the sump temperature, and the specified pH value. The equilibrium quantities of boric acid species are calculated iteratively based on its molal equilibrium quotients. The equilibrium quantities of phosphoric acid species are calculated iteratively based on its dissociation constants. The charge balance error (CBE) is the sum of ionic charges for all species and ions in the solution, including sodium. All species are in equilibrium when the CBE reduces to zero. The paper also presents the results of a parametric analysis that is performed using this computer program. Ranges of borated water quantity, boron concentration, and sump temperature are considered. For these borated water quantities and sump conditions, TSP quantities required to achieve sump pH values that range from 7.0 to 8.0 are determined. The results show significant dependence on temperature. In addition, the paper provides recommendations regarding TSP basket sizing and locations within the sump, as well as pH surveillance test requirements.
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Park, Sinwook, Praveen Kunchala, Hyejin Moon y Bumsoo Han. "High Throughput Characterization of Cryoprotective Agent Mixtures Using an EWOD-Based Digital Microfluidic Device". En ASME 2010 Summer Bioengineering Conference. American Society of Mechanical Engineers, 2010. http://dx.doi.org/10.1115/sbc2010-19273.
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One of the most challenging issues in cryopreservation is to identify new and improved cryoprotective agents (CPAs) or CPA mixtures beyond widely used dimethyl sulfoxide (DMSO). In order to address this challenge, numerous combinations of CPA mixtures need to be prepared, characterized, and screened. The characterization includes thermal properties and phase change behavior during freezing and thawing. For an example, Han et al. [1] performed analysis of the phase change behavior and the thermal properties of phosphate buffers saline (PBS) with various chemical additives (CPAs, AFPs, excess salts) using a differential scanning calorimeter and a cryo-microscope. Considering the number of possible compositions and concentration of CPA mixtures, a high throughput (HTP) screening platform capable of preparing and characterizing array of CPA mixtures is highly desired.
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Hu, Jianqiang, Zhanhe Du y Junbing Yao. "Study on Tribological Properties of Cadmium Dialkyl-Dithiophosphyl-ldithiophosphate Additive". En ASME 2005 International Mechanical Engineering Congress and Exposition. ASMEDC, 2005. http://dx.doi.org/10.1115/imece2005-79888.
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An cadmium dialkyl-dithiophosphyl-dithiophosphate additive was synthesized. A four-ball tester was used to evaluate the tribological performance of the additive in mineral base oil under different loads, compared with commercial additives. The results show that it exhibits excellent antiwear and load-carrying capacities and better than these additives. The surface analytical tools such as Auger Electron Spectrometer (AES), Scanning Electron Microscopy (SEM) with Energy Dispersive X-ray (EDX) were used to investigate the topography, the contents and the depth profile of some typical elements on the rubbing surface of worn scar. Smooth and light topography of worn scar further confirms that the additive showed good antiwear capacities, the results of Auger electron spectrometer and energy dispersive X-ray analysis indicate that tribochemically protective films consists of cadmium compouds, sulfides, sulphates and phosphates were formed on the rubbing surface, which contribute to improving the tribological properties of lubricants. Particularly, the results from depth profile indicate that a large amounts of cadmium are rich in outer layer of surface, which play an important role in improving antiwear properties of oils. Finally, the antiwear mechanism of the additive were proposed.
Informes sobre el tema "Phosphate additives"
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Litaor, Iggy, James Ippolito, Iris Zohar y Michael Massey. Phosphorus capture recycling and utilization for sustainable agriculture using Al/organic composite water treatment residuals. United States Department of Agriculture, enero de 2015. http://dx.doi.org/10.32747/2015.7600037.bard.
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Objectives: 1) develop a thorough understanding of the sorption mechanisms of Pi and Po onto the Al/O- WTR; 2) determine the breakthrough range of the composite Al/O-WTR during P capturing from agro- wastewaters; and 3) critically evaluate the performance of the composite Al/O-WTR as a fertilizer using selected plants grown in lysimeters and test-field studies. Instead of lysimeters we used pots (Israel) and one- liter cone-tainers (USA). We conducted one field study but in spite of major pretreatments the soils still exhibited high enough P from previous experiments so no differences between control and P additions were noticeable. Due to time constrains the field study was discontinued. Background: Phosphorous, a non-renewable resource, has been applied extensively in fields to increase crop yield, yet consequently has increased the potential of waterway eutrophication. Our proposal impetus is the need to develop an innovative method of P capturing, recycling and reuse that will sustain agricultural productivity while concurrently reducing the level of P discharge from and to agricultural settings. Major Conclusions & Achievements: An innovative approach was developed for P removal from soil leachate, dairy wastewater (Israel), and swine effluents (USA) using Al-based water treatment residuals (Al- WTR) to create an organic-Al-WTR composite (Al/O-WTR), potentially capable of serving as a P fertilizer source. The Al-WTR removed 95% inorganic-P, 80% to 99.9% organic P, and over 60% dissolved organic carbon from the agro-industrial waste streams. Organic C accumulation on particles surfaces possibly enhanced weak P bonding and facilitated P desorption. Analysis by scanning electron microscope (SEM- EDS), indicated that P was sparsely sorbed on both calcic and Al (hydr)oxide surfaces. Sorption of P onto WW-Al/O-WTR was reversible due to weak Ca-P and Al-P bonds induced by the slight alkaline nature and in the presence of organic moieties. Synchrotron-based microfocused X-ray fluorescence (micro-XRF) spectrometry, bulk P K-edge X-ray absorption near edge structure spectroscopy (XANES), and P K-edge micro-XANES spectroscopy indicated that adsorption was the primary P retention mechanism in the Al- WTR materials. However, distinct apatite- or octocalciumphosphatelike P grains were also observed. Synchrotron micro-XRF mapping further suggested that exposure of the aggregate exteriors to wastewater caused P to diffuse into the porous Al-WTR aggregates. Organic P species were not explicitly identified via P K-edge XANES despite high organic matter content, suggesting that organic P may have been predominantly associated with mineral surfaces. In screen houses experiments (Israel) we showed that the highest additions of Al/O-WTR (5 and 7 g kg⁻¹) produced the highest lettuce (Lactuca sativa L. var. longifolial) yield. Lettuce yield and P concentration were similar across treatments, indicating that Al/O- WTR can provide sufficient P to perform similarly to common fertilizers. A greenhouse study (USA) was utilized to compare increasing rates of swine wastewater derived Al/O-WTR and inorganic P fertilizer (both applied at 33.6, 67.3, and 134.5 kg P₂O₅ ha⁻¹) to supply plant-available P to spring wheat (TriticumaestivumL.) in either sandy loam or sandy clay loam soil. Spring wheat straw and grain P uptake were comparable across all treatments in the sandy loam, while Al/O-WTR application to the sandy clay loam reduced straw and grain P uptake. The Al/O-WTR did not affect soil organic P concentrations, but did increase phosphatase activity in both soils; this suggests that Al/O-WTR application stimulated microorganisms and enhance the extent to which microbial communities can mineralize Al/O-WTR-bound organic P. Implications: Overall, results suggest that creating a new P fertilizer from Al-WTR and agro-industrial waste sources may be a feasible alternative to mining inorganic P fertilizer sources, while protecting the environment from unnecessary waste disposal.