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Sample records for simultaneous coagulation sintering

  1. Bivariate Extension of the Quadrature Method of Moments for Modeling Simultaneous Coagulation and Sintering of Particle Populations.

    Science.gov (United States)

    Wright, Douglas L.; McGraw, Robert; Rosner, Daniel E.

    2001-04-15

    We extendthe application of moment methods to multivariate suspended particle population problems-those for which size alone is insufficient to specify the state of a particle in the population. Specifically, a bivariate extension of the quadrature method of moments (QMOM) (R. McGraw, Aerosol Sci. Technol. 27, 255 (1997)) is presented for efficiently modeling the dynamics of a population of inorganic nanoparticles undergoing simultaneous coagulation and particle sintering. Continuum regime calculations are presented for the Koch-Friedlander-Tandon-Rosner model, which includes coagulation by Brownian diffusion (evaluated for particle fractal dimensions, D(f), in the range 1.8-3) and simultaneous sintering of the resulting aggregates (P. Tandon and D. E. Rosner, J. Colloid Interface Sci. 213, 273 (1999)). For evaluation purposes, and to demonstrate the computational efficiency of the bivariate QMOM, benchmark calculations are carried out using a high-resolution discrete method to evolve the particle distribution function n(nu, a) for short to intermediate times (where nu and a are particle volume and surface area, respectively). Time evolution of a selected set of 36 low-order mixed moments is obtained by integration of the full bivariate distribution and compared with the corresponding moments obtained directly using two different extensions of the QMOM. With the more extensive treatment, errors of less than 1% are obtained over substantial aerosol evolution, while requiring only a few minutes (rather than days) of CPU time. Longer time QMOM simulations lend support to the earlier finding of a self-preserving limit for the dimensionless joint (nu, a) particle distribution function under simultaneous coagulation and sintering (Tandon and Rosner, 1999; D. E. Rosner and S. Yu, AIChE J., 47 (2001)). We demonstrate that, even in the bivariate case, it is possible to use the QMOM to rapidly model the approach to asymptotic behavior, allowing an immediate assessment of

  2. Simultaneous lactic acidification and coagulation by using recombinant Lactococcus lactis strain.

    Science.gov (United States)

    Raftari, M; Ghafourian, S; Abu Bakar, F

    2017-04-01

    This study was an attempt to create a novel milk clotting procedure using a recombinant bacterium capable of milk coagulation. The Rhizomucor pusillus proteinase (RPP) gene was sub-cloned into a pALF expression vector. The recombinant pALF-RPP vector was then electro-transferred into Lactococcus lactis. Finally, the milk coagulation ability of recombinant L. lactis carrying a RPP gene was evaluated. Nucleotide sequencing of DNA insertion from the clone revealed that the RPP activity corresponded to an open reading frame consisting of 1218 bp coding for a 43·45 kDa RPP protein. The RPP protein assay results indicated that the highest RPP enzyme expression with 870 Soxhlet units (SU) per ml and 7914 SU/OD were obtained for cultures which were incubated at pH 5·5 and 30°C. Interestingly, milk coagulation was observed after 205 min of inoculating milk with recombinant L. lactis carrying the RPP gene. The recombinant L. lactis carrying RPP gene has the ability to function as a starter culture for acidifying and subsequently coagulating milk by producing RPP as a milk coagulant agent. Creating a recombinant starter culture bacterium that is able to coagulate milk. It is significant because the recombinant L. lactis has the ability to work as a starter culture and milk coagulation agent. © 2016 The Society for Applied Microbiology.

  3. Simultaneous optimization of multiple performance characteristics in coagulation-flocculation process for Indian paper industry wastewater.

    Science.gov (United States)

    Saraswathi, R; Saseetharan, M K

    2012-01-01

    The goal of this study was to optimize the coagulation-flocculation process in wastewater generated from the paper and pulp industry using a grey relational analysis (GRA)-based Taguchi method. Process parameters included types and doses of natural coagulants and coagulant aid, and pH. To track the efficiency of the treatment process, the following responses were chosen for optimization: chemical oxygen demand (COD), total dissolved solids (TDS) and turbidity of wastewater, alone or in combination or all together. Analysis of variance showed that the type and dose of the coagulant aid were the most significant parameters, followed by pH and the dose of the coagulant; the type of coagulant used was found to be insignificant in the coagulation-flocculation process. Optimization of process parameters to achieve lower turbidity and greater removal of COD and TDS was verified in a separate confirmatory experiment, which showed improvements in COD and TDS removal and a decrease in turbidity of 8.2, 6.35 and 26.17%, respectively, with the application of the Taguchi method and GRA.

  4. A pilot study for determining the optimal operation condition for simultaneously controlling the emissions of PCDD/Fs and PAHs from the iron ore sintering process.

    Science.gov (United States)

    Chen, Yu-Cheng; Tsai, Perng-Jy; Mou, Jin-Luh; Kuo, Yu-Chieh; Wang, Shih-Min; Young, Li-Hao; Wang, Ya-Fen

    2012-09-01

    In this study, the cost-benefit analysis technique was developed and incorporated into the Taguchi experimental design to determine the optimal operation combination for the purpose of providing a technique solution for controlling both emissions of PCDD/Fs and PAHs, and increasing both the sinter productivity (SP) and sinter strength (SS) simultaneously. Four operating parameters, including the water content, suction pressure, bed height, and type of hearth layer, were selected and all experimental campaigns were conducted on a pilot-scale sinter pot to simulate various sintering operating conditions of a real-scale sinter plant. The resultant optimal combination could reduce the total carcinogenic emissions arising from both emissions of PCDD/Fs and PAHs by 49.8%, and increase the sinter benefit associated with the increase in both SP and SS by 10.1%, as in comparison with the operation condition currently used in the real plant. The ANOVA results indicate that the suction pressure was the most dominant parameter in determining the optimal operation combination. The above result was theoretically plausible since the higher suction pressure provided more oxygen contents leading to the decrease in both PCDD/F and PAH emissions. But it should be noted that the results obtained from the present study were based on pilot scale experiments, conducting confirmation tests in a real scale plant are still necessary in the future. Copyright © 2012 Elsevier Ltd. All rights reserved.

  5. A DOC coagulant, gypsum treatment can simultaneously reduce As, Cd and Pb uptake by medicinal plants grown in contaminated soil.

    Science.gov (United States)

    Kim, Hyuck Soo; Seo, Byoung-Hwan; Kuppusamy, Saranya; Lee, Yong Bok; Lee, Jae-Hwang; Yang, Jae-E; Owens, Gary; Kim, Kwon-Rae

    2018-02-01

    The efficiency of gypsum, as a dissolved organic carbon (DOC) coagulator, for the simultaneous immobilization of two heavy metals (Cd and Pb) and one metalloid (As) in agricultural soils near an abandoned mining site was examined. The agricultural soil was defined as long-term contaminated as As (1540mgkg -1 ), Cd (55mgkg -1 ) and Pb (1283mgkg -1 ) concentrations exceeded the Korean guideline values for As (25mgkg -1 ), Cd (4mgkg -1 ), and Pb (200mgkg -1 ). Gypsum was incorporated into the contaminated soil at 3% (w/w). In comparison two commonly using immobilizing agents (lime and compost), together with a mixture (lime+gypsum) were also included in the pot trial for the cultivation of two medical plants (A. gigas and A. macrocephala) and to evaluate the effectiveness of gypsum on As, Cd and Pb immobilization. The results showed that even though pH change-induced immobilizing agents such as lime were more effective than gypsum at immobilizing Cd and Pb, addition of gypsum also effectively reduced heavy metal phytoavailability as indicated by decreases in the concentration of Cd and Pb in medicinal plants. Furthermore, gypsum and gypsum+ lime were also most effective in reducing As concentrations in both plants studied. This was mainly attributed to significant decreases in soil DOC (48-64%) when gypsum and gypsum+lime were applied to the soil. Consequently, it was concluded that enhanced DOC coagulation with gypsum, could be considered as a promising technique for the immobilization of both metals (Cd and Pb) and metalloids (As) in agricultural soils. Copyright © 2017 Elsevier Inc. All rights reserved.

  6. Dual-sided electrosurgery handpiece for simultaneous tissue cutting and coagulation: first report on a conceptual design validated by an animal experiment.

    Science.gov (United States)

    Tawfik, Hatem A; Fouad, Yousef A; Hafez, Rashad

    2015-01-01

    To introduce and evaluate the safety of a novel dual-sided electrosurgery handpiece design for simultaneous tissue cutting and coagulation. We designed a prototype double-sided handpiece allowing automatic switching between two electrodes with a simple handpiece flip. The concept of the system as a surgical instrument was assessed by an animal experiment. The skin of 15 Wistar albino white rats could be successfully incised and coagulated using both ends of the handpiece, thereby confirming the prospects and clinical applications of the system. The dual-sided electrosurgery handpiece is a simple and safe alternative to the traditional electrosurgery pencil, allowing the simultaneous use of two electrodes without the hassle of frequent electrode replacement.

  7. Simultaneous removal of nano-ZnO and Zn2+based on transportation character of nano-ZnO by coagulation: Enteromorpha polysaccharide compound polyaluminum chloride.

    Science.gov (United States)

    Sun, Jianzhang; Gao, Baoyu; Zhao, Shuang; Li, Ruihua; Yue, Qinyan; Wang, Yan; Liu, Siqi

    2017-02-01

    It is confirmed that nano-ZnO (nZnO) has impact on environment and is considered as heavy metal pollutants. It is a new technology that applies coagulation process to simultaneous removal of the nanoparticles and heavy metals. Environmental chemical behavior of ZnO in water, such as the dispersion, aggregation, sedimentation, and dissolution of releasing metal ions, has been systematically studied in this paper. The result shows that three kinds of nZnO state such as compacted sediment, suspended, and released is separately 36.54 %, 40.61 %, and 22.86 %. Enteromorpha polysaccharide (Ep) was used together with polyaluminum chloride (PAC) in surface water purification. In order to study the mechanism of simultaneous removal of residual nZnO particles and Zn 2+ , coagulation process was further applied in this study. The evolution of flocs size, strength, and recovery ability and fractal structure due to Ep addition was systematically studied in this paper. Results indicated that PAC-Ep was efficient in removing nZnO and Zn 2+ , which leads to more than 95 % particles, 50-60 % natural organic matter (NOM) removed, and 35 % of resolved heavy metal ion adsorbing-chelation. Ep was an efficient coagulant aid in enhancing performance of coagulation and generating flocs with bigger sizes, faster growth rates, and higher recovery abilities. Additionally, the flocs formed by PAC-Ep presented a much looser structure than flocs formed only by PAC. Graphical abstract ᅟ.

  8. Potentially life-threatening coagulopathy associated with simultaneous reduction in coagulation and fibrinolytic function in pediatric acute leukemia after hematopoietic stem-cell transplantation.

    Science.gov (United States)

    Ishihara, Takashi; Nogami, Keiji; Matsumoto, Tomoko; Nomura, Akitaka; Takeshita, Yasufumi; Ochi, Satoshi; Shima, Midori

    2017-07-01

    The pathogenesis of sinusoidal obstruction syndrome (SOS) and thrombotic microangiopathy (TMA) after hematopoietic stem cell transplantation (HSCT) is poorly understood, and limited information is available on global hemostatic function in HSCT. We assessed changes in coagulation and fibrinolysis using a simultaneous thrombin and plasmin generation assay (T/P-GA) during HSCT. Measurements of endogenous thrombin potential (T-EP) and plasmin peak height (P-Peak) using T/P-GA in six pediatric acute leukemia patients treated with HSCT were compared to normal plasma. In the SOS case, the ratios of T-EP and P-Peak to normal were simultaneously decreased at four weeks post-HSCT (Pre; ~1.1/1.1-1.4, Week+4; 0.14/0.0084, respectively). Similarly, in the TMA patient, both ratios were decreased at 3 weeks and recovered after 8 weeks (Pre; 1.2/~0.95, Week+3; 0.59/0.22, Week+8; 1.2/0.64-0.85). In the other patients, when SOS/TMA was not evident, the T/P-GA data remained within normal limits. These findings suggest that the simultaneous reduction of coagulation and fibrinolytic function in patients developing SOS/TMA can lead to a life-threatening coagulopathy. Further research is warranted to clarify global hemostatic function after HSCT to establish optimal supportive therapy for these critical clinical disorders of hemostasis.

  9. Mechanical properties of simultaneously synthesized and consolidated carbon nanofiber (CNF)-dispersed SiC composites by pulsed electric-current pressure sintering

    International Nuclear Information System (INIS)

    Hirota, Ken; Hara, Hiroaki; Kato, Masaki

    2007-01-01

    Carbon nanofiber (CNF) dispersed β-SiC composites with the addition of 0.2 mass% boron and 2.0 mass% carbon as sintering aids have been synthesized and consolidated simultaneously from mixtures of Si, amorphous C and B powders and CNF by pulsed electric-current pressure sintering (PECPS). Synthesis and consolidation process, which were observed from their expansion and shrinkage curves during PECPS, have been examined using X-ray diffraction and scanning electron microscopy for the powder compacts. CNF/SiC composites sintered at 1800 deg. C for 10 min under 40 MPa in a vacuum have ∼96.0% of theoretical density and homogeneous structures consisting of ∼4.0 μm grains. A 10 vol% CNF/SiC composite exhibited excellent mechanical properties: a bending strength of ∼720 MPa, a Vickers hardness of ∼26.0 GPa, and a fracture toughness of ∼5.5 MPa m 1/2 . High-temperature bending strength of ∼890 MPa at 1200 deg. C in air was attained with the same nanocomposites

  10. Simultaneous synthesis and consolidation of chromium carbides (Cr3C2, Cr7C3 and Cr23C6) by pulsed electric-current pressure sintering

    International Nuclear Information System (INIS)

    Hirota, Ken; Mitani, Kenichi; Yoshinaka, Masaru; Yamaguchi, Osamu

    2005-01-01

    Chromium carbides (Cr 3 C 2 , Cr 7 C 3 and Cr 23 C 6 ) have been synthesized and consolidated simultaneously from mixtures of Cr and amorphous carbon powders by pulsed electric-current pressure sintering (PECPS). Dense ceramics thus obtained were composed of chromium carbides with a small amount of Cr 2 O 3 , which originates from a trace amount of oxygen adsorbed on the as-received starting Cr powder. Synthesis and consolidation processes, which were observed from their shrinkage curves during PECPS, have been examined using X-ray diffraction (XRD) and scanning electron microscopy for the powder compacts. Cr 3 C 2 ceramics sintered at 1300 deg. C for 10 min under 30 MPa have a 98.9% of theoretical density and fine structures with a 3.6 μm grain size. They exhibit excellent mechanical properties: a bending strength σ b of 690 MPa, a Vickers hardness H v of 18.9 GPa and a fracture toughness K IC of 7.1 MPa m 1/2

  11. Simultaneous determination of nine preservatives in food by liquid chromatography with the aid of coagulant in the clean-up process.

    Science.gov (United States)

    Sugiura, Jun; Nakajima, Masahiro

    2017-05-01

    A simple HPLC method was developed for the simultaneous analysis of nine preservatives in food including benzoic acid, sorbic acid, dehydroacetic acid, methyl paraben, ethyl paraben, isopropyl paraben, propyl paraben, isobutyl paraben and butyl paraben. Samples were extracted with 60 v/v% methanol containing poly-aluminium chloride (PAC) and sodium hydroxide prior to analysis. PAC, which is normally used as a coagulant, was successfully applied to remove interfering substances from the samples. The method showed good linearity with coefficients of determination higher than 0.999 over the range of 0.2-5 µg ml -1 for all target preservatives. LOQs of the method were in the range of 0.002-0.008 g kg -1 . Method performance was evaluated in a variety of foods demonstrated to have quantitative recoveries of 81.7-102.5% with satisfactory intra-day precision of foods containing preservatives.

  12. Simultaneous removal of oil and grease, and heavy metals from artificial bilge water using electro-coagulation/flotation.

    Science.gov (United States)

    Rincón, Guillermo J; La Motta, Enrique J

    2014-11-01

    US and international regulations pertaining to the control of bilge water discharges from ships have concentrated their attention to the levels of oil and grease rather than to the heavy metal concentrations. The consensus is that any discharge of bilge water (and oily water emulsion within 12 nautical miles from the nearest land cannot exceed 15 parts per million (ppm). Since there is no specific regulation for metal pollutants under the bilge water section, reference standards regulating heavy metal concentrations are taken from the ambient water quality criteria to protect aquatic life. The research herein presented discusses electro-coagulation (EC) as a method to treat bilge water, with a focus on oily emulsions and heavy metals (copper, nickel and zinc) removal efficiency. Experiments were run using a continuous flow reactor, manufactured by Ecolotron, Inc., and a synthetic emulsion as artificial bilge water. The synthetic emulsion contained 5000 mg/L of oil and grease, 5 mg/L of copper, 1.5 mg/L of nickel, and 2.5 mg/l of zinc. The experimental results demonstrate that EC is very efficient in removing oil and grease. For oil and grease removal, the best treatment and cost efficiency was obtained when using a combination of carbon steel and aluminum electrodes, at a detention time less than one minute, a flow rate of 1 L/min and 0.6 A/cm(2) of current density. The final effluent oil and grease concentration, before filtration, was always less than 10 mg/L. For heavy metal removal, the combination of aluminum and carbon steel electrodes, flow rate of 1 L/min, effluent recycling, and 7.5 amps produced 99% zinc removal efficiency. Copper and nickel are harder to remove, and a removal efficiency of 70% was achieved. Copyright © 2014 Elsevier Ltd. All rights reserved.

  13. Sinterable powders

    International Nuclear Information System (INIS)

    Zanghi, J.S.; Kasprzyk, M.R.

    1979-01-01

    A description is given of sinterable powders and methods of producing sintered products using such powders. The powders consist of (a) a particulate ceramic material, e.g. SiC, having specified particle size and surface area; (b) a carbon source material, e.g. sugar or a phenol-formaldehyde resin; and (c) a residue from a solution of H 3 BO 3 , B 2 O 3 , or mixtures of these as sintering aid. (U.K.)

  14. Coagulation defects.

    Science.gov (United States)

    Soliman, Doreen E; Broadman, Lynn M

    2006-09-01

    The present understanding of the coagulation process emphasizes the final common pathway and the proteolytic systems that result in the degradation of formed clots and the prevention of unwanted clot formations, as well as a variety of defense systems that include tissue repair, autoimmune processes, arteriosclerosis, tumor growth, the spread of metastases, and defense systems against micro-organisms. This article discusses diagnosis and management of some of the most common bleeding disorders. The goals are to provide a simple guide on how best to manage patients afflicted with congenital or acquired clotting abnormalities during the perioperative period, present a brief overview of the methods of testing and monitoring the coagulation defects, and discuss the appropriate pharmacologic or blood component therapies for each disease.

  15. Coagulation management.

    Science.gov (United States)

    Grottke, Oliver

    2012-12-01

    Trauma-induced coagulopathy is a frequent complication in severely injured patients. To correct coagulopathy and restore haemostasis, these patients have traditionally been treated with fresh frozen plasma, but in the last decade, there has been a shift from empirical therapy to targeted therapy with coagulation factor concentrates and other haemostatic agents. This review highlights emerging therapeutic options and controversial topics. Early administration of the antifibrinolytic medication tranexamic acid was shown in the multicentre CRASH-2 trial to be an effective and inexpensive means of decreasing blood loss. Numerous retrospective and experimental studies have shown that the use of coagulation factor concentrates decreases blood loss and may be useful in reducing the need for transfusion of allogeneic blood products. In particular, early use of fibrinogen concentrate and thrombin generators has a positive impact on haemostasis. However, the use of prothrombin complex concentrate to correct trauma-induced coagulopathy has also been associated with a potential risk of serious adverse events. Current evidence in trauma resuscitation indicates a potential role for coagulation factor concentrates and other haemostatic agents in correcting trauma-induced coagulopathy. Despite a shift towards such transfusion strategy, there remains a shortage of data to support this approach.

  16. Inflammation and coagulation

    NARCIS (Netherlands)

    Levi, Marcel; van der Poll, Tom

    2010-01-01

    In the pathogenesis of sepsis, inflammation and coagulation play a pivotal role. Increasing evidence points to an extensive cross-talk between these two systems, whereby inflammation leads to activation of coagulation, and coagulation also considerably affects inflammatory activity. Molecular

  17. Simultaneous Synthesis and Sintering of a Nanocrystalline AlCr{sub 2}-Al2O{sub 3} Composite by Rapid Heating and Its Mechanical Properties

    Energy Technology Data Exchange (ETDEWEB)

    Kwak, Bong-Won; Lee Seok-Jae; Shon, In-Jin [Chonbuk National University, Jeonju (Korea, Republic of)

    2016-06-15

    A dense nanostuctured AlCr{sub 2}-Al2O{sub 3} composite was sintered by pulsed current activated heating up to 1200 °C within 2 min from mechanically milled powders. The advantage of this process is that it allows very quick densification to near theoretical density and prohibition of grain growth in nanostructured materials. A highly dense AlCr{sub 2}-Al{sub 2}O{sub 3} composite with a relative density of up to 96% was produced under application of a 80 MPa pressure and a pulsed current of 2000 A. The fracture toughness and hardness of the AlCr{sub 2}-Al{sub 2}O{sub 3} composite in this study was better than those of previous studies due to the grain refinement. The microstructure and mechanical properties of the composite were investigated using field emission scanning electron microscopy and a Vickers hardness tester.

  18. Sintering and densification; new techniques: sinter forging

    International Nuclear Information System (INIS)

    Winnubst, A.J.A.

    1998-01-01

    In this chapter pressure assisted sintering methods will be described. Attention will mainly be paid to sinter forging as a die-wall free uniaxial pressure sintering technique, where large creep strains are possible. Sinter forging is an effective tool to reduce sintering temperature and time and to obtain a nearly theoretically dense ceramic. In this way grain size in tetragonal zirconia ceramics can be reduced down to 100 nm. Another important phenomenon is the reduction of the number density and size of cracks and flaws resulting in higher strength and improved reliability, which is of utmost importance for engineering ceramics. The creep deformation during sinter forging causes a rearrangement of the grains resulting in a reduction of interatomic spaces between grains, while grain boundary (glassy) phases can be removed. The toughness and in some cases the wear resistance is enhanced after sinter forging as a result of the grain-boundary-morphology improvement. (orig.)

  19. Coagulation disorders in intensive care

    NARCIS (Netherlands)

    Levi, Marcel

    2009-01-01

    Coagulation disorders are common in intensive care patients and may range from isolated thrombocytopenia or prolonged clotting times to disseminated intravascular coagulation. There are many causes of disturbed coagulation in critically ill patients and each may require specific treatment

  20. Disseminated intravascular coagulation in sepsis

    NARCIS (Netherlands)

    Zeerleder, Sacha; Hack, C. Erik; Wuillemin, Walter A.

    2005-01-01

    Disseminated intravascular coagulation is a frequent complication of sepsis. Coagulation activation, inhibition of fibrinolysis, and consumption of coagulation inhibitors lead to a procoagulant state resulting in inadequate fibrin removal and fibrin deposition in the microvasculature. As a

  1. Sintering of nonstoichiometric UO2

    International Nuclear Information System (INIS)

    Susnik, D.; Holc, J.

    1983-01-01

    Activated sintering of UO 2 pellets at 1100 deg C is described. In CO 2 atmosphere is UO 2 is nonstoichiometric and pellets from active UO 2 powders sinter at 900 deg C to high density. At 1100 deg C the final sintered density is practically achieved at heating on sintering temperature. After reduction and cooling in H 2 atmosphere which is followed sintering in CO 2 the structure is identical to the structured UO 2 pellets sintered at high temperature in H 2 . Density of activated sintered UO 2 pellets is stable, even after additional sintering at 1800 deg C. (author)

  2. Laser Sintered Calcium Phosphate Bone

    National Research Council Canada - National Science Library

    Vail, Neil

    1999-01-01

    ...) technology selective laser sintering (SLS). BME has successfully implemented a pilot facility to fabricate calcium phosphate implants using anatomical data coupled with the selective laser sintering process...

  3. A method for sintering

    DEFF Research Database (Denmark)

    2012-01-01

    The present invention provides a method for sintering, comprising in the following order the steps of: providing a body in the green state or in the pre-sintered state on a support; providing a load on at least one spacer on the support such that the load is located above said body in the green...

  4. Production and Characterization of Water Treatment Coagulant from ...

    African Journals Online (AJOL)

    ADOWIE PERE

    Production of liquid alum coagulant from local. Saudi clays, JKAU, Eng. Sci.5. (1) 3-17. Bai, GH. Teng, W; Wang, XG, Qin, J.-G. Xu, P and. Li, PC (2010). Alkali desilicated coal fly ash as substitute of bauxite in lime-soda sintering process for aluminum production. Trans. Non. Met. Soc. of China, 20(1)169–175,. Chigondo, F ...

  5. Dust coagulation in ISM

    Science.gov (United States)

    Chokshi, Arati; Tielens, Alexander G. G. M.; Hollenbach, David

    1989-01-01

    Coagulation is an important mechanism in the growth of interstellar and interplanetary dust particles. The microphysics of the coagulation process was theoretically analyzed as a function of the physical properties of the coagulating grains, i.e., their size, relative velocities, temperature, elastic properties, and the van der Waal interaction. Numerical calculations of collisions between linear chains provide the wave energy in individual particles and the spectrum of the mechanical vibrations set up in colliding particles. Sticking probabilities are then calculated using simple estimates for elastic deformation energies and for the attenuation of the wave energy due to absorption and scattering processes.

  6. Sintering of beryllium oxide

    International Nuclear Information System (INIS)

    Caillat, R.; Pointud, R.

    1955-01-01

    This study had for origin to find a process permitting to manufacture bricks of beryllium oxide of pure nuclear grade, with a density as elevated as possible and with standardized shape. The sintering under load was the technique kept for the manufacture of the bricks. Because of the important toxicity of the beryllium oxide, the general features for the preliminary study of the sintering, have been determined while using alumina. The obtained results will be able to act as general indication for ulterior studies with sintering under load. (M.B.) [fr

  7. Coagulation and Mental Disorders

    Directory of Open Access Journals (Sweden)

    Silvia Hoirisch-Clapauch

    2014-10-01

    Full Text Available The neurovascular unit is a key player in brain development, homeostasis, and pathology. Mental stress affects coagulation, while severe mental illnesses, such as recurrent depression and schizophrenia, are associated with an increased thrombotic risk and cardiovascular morbidity. Evidence indicates that the hemostatic system is involved to some extent in the pathogenesis, morbidity, and prognosis of a wide variety of psychiatric disorders. The current review focuses on emerging data linking coagulation and some psychiatric disorders.

  8. Morphological analysis and modelling of sintering and of sintered materials

    International Nuclear Information System (INIS)

    Jernot, Jean-Paul

    1982-01-01

    This research thesis addresses the study of solid phase sintering of metallic powders, and aims at describing as precisely as possible the different involved matter transport mechanisms, first by using a thermodynamic approach to sintering. Sintering diagrams are also used to determine prevailing mechanisms. The microstructure of sintered materials has been studied by using image quantitative analysis, thus by using a morphological approach to sintering. Morphological parameters allow, on the one hand, the evolution of powders during sintering to be followed, and, on the other hand, sintered products to be correctly characterised. Moreover, the author reports the study of the evolution of some physical properties of sintered materials with respect to their microstructure parameters. This leads to the development of a modelling of the behaviour of these materials [fr

  9. Sintering of Synroc D

    International Nuclear Information System (INIS)

    Robinson, G.

    1982-01-01

    Sintering has been investigated as a method for the mineralization and densification of high-level nuclear defense waste powder. Studies have been conducted on Synroc D composite powder LS04. Optimal densification has been found to be highly dependent on the characteristics of the starting material. Powder subjected to milling, which was believed to reduce the level of agglomeration and possibly particle size, was found to densify better than powder not subjected to this milling. Densities of greater than 95% of theoretical could be achieved for samples sintered at 1150 to 1200 0 C. Mineralogy was found to be as expected for Synroc D for samples sintered in a CO 2 /CO atmosphere where the Fe +2 /Fe +3 ratio was maintained at 1.0 to 5.75. In a more oxidizing, pure CO 2 atmosphere a new phase, not previously identified in Synroc D, was found

  10. Low density, variation in sintered density and high nitrogen in uranium dioxide

    International Nuclear Information System (INIS)

    Balakrishna, Palanki; Murty, B.N.; Anuradha, M.; Nageshwara Rao, P.; Jayaraj, R.N.; Ganguly, C.

    2000-01-01

    Low sintered density and density variation in sintered UO 2 were found to have been caused by non uniformity in the granule feed characteristics to the compacting press. The nitrogen impurity content of sintered UO 2 was found to be sintering furnace related and associated with low sintered density pellets. The problems of low density, variation in sintered density and high nitrogen could be solved by the replacement of the prevailing four punch precompaction by a single punch process; by the introduction of a vibro-sieve for the separation of fine particles from the press feed granules; by innovation in the powder feed shoe design for simultaneous and uniform dispensing of powder in all the die holes; by increasing the final compaction pressure and by modifying the gas flows and preheat temperature in the sintering furnace. (author)

  11. SinterHab

    Science.gov (United States)

    Rousek, Tomáš; Eriksson, Katarina; Doule, Ondřej

    2012-05-01

    This project describes a design study for a core module on a Lunar South Pole outpost, constructed by 3D printing technology with the use of in-situ resources and equipped with a bio-regenerative life support system. The module would be a hybrid of deployable (CLASS II) and in-situ built (CLASS III) structures. It would combine deployable membrane structures and pre-integrated rigid elements with a sintered regolith shell for enhanced radiation and micrometeorite shielding. The closed loop ecological system would support a sustainable presence on the Moon with particular focus on research activities. The core module accommodates from four to eight people, and provides laboratories as a test bed for development of new lunar technologies directly in the environment where they will be used. SinterHab also includes an experimental garden for development of new bio-regenerative life support system elements. The project explores these various concepts from an architectural point-of-view particularly, as they constitute the building, construction and interior elements. The construction method for SinterHab is based on 3D printing by sintering of the lunar regolith. Sinterator robotics 3D printing technology proposed by NASA JPL enables construction of future generations of large lunar settlements with little imported material and the use of solar energy. The regolith is processed, placed and sintered by the Sinterator robotics system which combines the NASA ATHLETE and the Chariot remotely controlled rovers. Microwave sintering creates a rigid structure in the form of walls, vaults and other architectural elements. The interior is coated with a layer of inflatable membranes inspired by the TransHab project. The life-support system is mainly bio-regenerative and several parts of the system are intrinsically multifunctional and serve more than one purpose. The plants for food production are also an efficient part of atmosphere revitalization and water treatment. Moreover

  12. Removal of Dye in Wastewater by Adsorption-Coagulation Combined System with Hibiscus sabdariffa as the Coagulant

    Directory of Open Access Journals (Sweden)

    Hoong Ho Nicholas Jian

    2018-01-01

    Full Text Available The conventional process to treat dye wastewater is the physicochemical treatment such as coagulation, flocculation and adsorption process. A new approach has been demonstrated to treat Congo red dye wastewater, which is the adsorption-coagulation hybrid process. Natural coagulant extracted from Hibiscus sabdariffa seeds is used as the coagulant while activated carbon is used as the adsorbent in this case study. The objective of this experiment is to study the significant factors that will affect the efficiency of dye removal. Then, the optimum conditions for the hybrid process is determined using Respond Surface Methodology (RSM. The variables are pH, initial dye concentration, coagulant dosage and adsorbent dosage while the response of experiment is the dye removal percentage. A three-level and four-variable Box-Behnken design (BBD is used for the RSM. A total of 27 sets of experimental results is required to determine the optimum conditions. Jar test is used to conduct the experiment with the addition of coagulant and adsorbent simultaneously. Based on the regression model analysis and ANOVA, the highly significant factors that contribute to the dye removal efficiency through adsorption-coagulation hybrid process are pH of solution and initial dye concentration. The RSM results shows that the optimised process parameters for adsorption-coagulation hybrid process with Hibiscus sabdariffa seeds as the coagulant and activated carbon as the adsorbent are pH 2, initial dye concentration of 385 ppm, coagulant dosage of 209 mg/L and adsorbent dosage of 150 mg/L. The dye removal reaches up to 96.67% under optimum parameters.

  13. Reheating of zinc-titanate sintered specimens

    Directory of Open Access Journals (Sweden)

    Labus N.

    2015-01-01

    Full Text Available The scope of this work was observing dimensional and heat transfer changes in ZnTiO3 samples during heating in nitrogen and air atmosphere. Interactions of bulk specimens with gaseous surrounding induce microstructure changes during heating. Sintered ZnTiO3 nanopowder samples were submitted to subsequent heating. Dilatation curves and thermogravimetric with simultaneous differential thermal analysis TGA/DTA curves were recorded. Reheating was performed in air and nitrogen atmospheres. Reheated samples obtained at different characteristic temperatures in air were analyzed by X-ray diffraction (XRD. Microstructures obtained by scanning electron microscopy (SEM of reheated sintered samples are presented and compared. Reheating in a different atmosphere induced different microstructures. The goal was indicating possible causes leading to the microstructure changes. [Projekat Ministarstva nauke Republike Srbije, br. OI172057 i br. III45014

  14. The 9-MilCA method as a rapid, partly automated protocol for simultaneously recording milk coagulation, curd firming, syneresis, cheese yield, and curd nutrients recovery or whey loss.

    Science.gov (United States)

    Cipolat-Gotet, C; Cecchinato, A; Stocco, G; Bittante, G

    2016-02-01

    The aim of this study was to propose and test a new laboratory cheesemaking procedure [9-mL milk cheesemaking assessment (9-MilCA)], which records 15 traits related to milk coagulation, curd firming, syneresis, cheese yield, and curd nutrients recovery or whey loss. This procedure involves instruments found in many laboratories (i.e., heaters and lacto-dynamographs), with an easy modification of the sample rack for the insertion of 10-mL glass tubes. Four trials were carried out to test the 9-MilCA procedure. The first trial compared 8 coagulation and curd firming traits obtained using regular or modified sample racks to process milk samples from 60 cows belonging to 5 breeds and 3 farms (480 tests). The obtained patterns exhibited significant but irrelevant between-procedure differences, with better repeatability seen for 9-MilCA. The second trial tested the reproducibility and repeatability of the 7 cheesemaking traits obtained using the 9-MilCA procedure on individual samples from 60 cows tested in duplicate in 2 instruments (232 tests). The method yielded very repeatable outcomes for all 7 tested cheese yield and nutrient recovery traits (repeatability >98%), with the exception of the fresh cheese yield (84%), which was affected by the lower repeatability (67%) of the water retained in the curd. In the third trial (96 tests), we found that using centrifugation in place of curd cooking and draining (as adopted in several published studies) reduced the efficiency of whey separation, overestimated all traits, and worsened the repeatability. The fourth trial compared 9-MilCA with a more complex model cheese-manufacturing process that mimics industry practices, using 1,500-mL milk samples (72 cows, 216 tests). The average results obtained from 9-MilCA were similar to those obtained from the model cheeses, with between-method correlations ranging from 78 to 99%, except for the water retained in the curd (r=54%). Our results indicate that new 9-MilCA method is a

  15. Sintering of B4C by pressureless liquid phase sintering

    International Nuclear Information System (INIS)

    Rocha, Rosa Maria da; Melo, Francisco Cristovao Lourenco de

    2009-01-01

    The effect of three different sintering additive systems on densification of boron carbide powder was investigated. The sintering additives were Al 2 O 3 :Y 2 O 3 , AlN:Y 2 O 3 and BN:Y 2 O 3 compositions. Powder mixtures were prepared with 10 vol% of sintering aids following conventional powder technology processes. Samples were sintered by pressureless sintering at 2050 deg C/30min in argon atmosphere. Sintered samples were compared to a sintered B 4 C without sintering additive. Samples were characterized by XRD to analyze the crystalline phases after sintering and SEM to observe the microstructure and the second phase distribution. YB 4 and YB 2 C 2 were identified in all samples, indicating a reaction between Y 2 O 3 , B 4 C and B 2 O 3 present at the B 4 C particle surface. The best densification result was achieved with Al 2 O 3 :Y 2 O 3 additive system, showing 92.0 % of theoretical density, low porosity and 15.2 % of linear shrinkage. But this sample showed the highest weight loss. (author)

  16. Activation of blood coagulation in cancer: implications for tumour progression

    Science.gov (United States)

    Lima, Luize G.; Monteiro, Robson Q.

    2013-01-01

    Several studies have suggested a role for blood coagulation proteins in tumour progression. Herein, we discuss (1) the activation of the blood clotting cascade in the tumour microenvironment and its impact on primary tumour growth; (2) the intravascular activation of blood coagulation and its impact on tumour metastasis and cancer-associated thrombosis; and (3) antitumour therapies that target blood-coagulation-associated proteins. Expression levels of the clotting initiator protein TF (tissue factor) have been correlated with tumour cell aggressiveness. Simultaneous TF expression and PS (phosphatidylserine) exposure by tumour cells promote the extravascular activation of blood coagulation. The generation of blood coagulation enzymes in the tumour microenvironment may trigger the activation of PARs (protease-activated receptors). In particular, PAR1 and PAR2 have been associated with many aspects of tumour biology. The procoagulant activity of circulating tumour cells favours metastasis, whereas the release of TF-bearing MVs (microvesicles) into the circulation has been correlated with cancer-associated thrombosis. Given the role of coagulation proteins in tumour progression, it has been proposed that they could be targets for the development of new antitumour therapies. PMID:23889169

  17. Boric oxide or boric acid sintering aid for sintering ceramics

    International Nuclear Information System (INIS)

    Lawler, H.A.

    1979-01-01

    The invention described relates to the use of liquid sintering aid in processes involving sintering of ceramic materials to produce dense, hard articles having industrial uses. Although the invention is specifically discussed in regard to compositions containing silicon carbide as the ceramic material, other sinterable carbides, for example, titanium carbide, may be utilized as the ceramic material. A liquid sintering aid for densifying ceramic material is selected from solutions of H 3 BO 3 , B 2 O 3 and mixtures of these solutions. In sintering ceramic articles, e.g. silicon carbide, a shaped green body is formed from a particulate ceramic material and a resin binder, and the green body is baked at a temperature of 500 to 1000 0 C to form a porous body. The liquid sintering aid of B 2 O 3 and/or H 3 BO 3 is then dispersed through the porous body and the treated body is sintered at a temperature of 1900 to 2200 0 C to produce the sintered ceramic article. (U.K.)

  18. Sintering of magnesia: effect of additives

    Indian Academy of Sciences (India)

    % was studied on the sinter- ing and microstructural developments of the chemically pure magnesia using the pressureless sintering technique between 1500 and 1600◦C. Sintering was evaluated by per cent densification and microstructural ...

  19. Enhanced WWTP effluent organic matter removal in hybrid ozonation-coagulation (HOC) process catalyzed by Al-based coagulant

    Energy Technology Data Exchange (ETDEWEB)

    Jin, Xin [School of Environmental and Municipal Engineering, Xi’an University of Architecture and Technology, Xi’an, Shaanxi Province, 710055 (China); Jin, Pengkang, E-mail: pkjin@hotmail.com [School of Environmental and Municipal Engineering, Xi’an University of Architecture and Technology, Xi’an, Shaanxi Province, 710055 (China); Hou, Rui [School of Environmental and Municipal Engineering, Xi’an University of Architecture and Technology, Xi’an, Shaanxi Province, 710055 (China); Yang, Lei [Department of Materials Science and Engineering, Monash University, Clayton, VIC, 3800 (Australia); Wang, Xiaochang C., E-mail: xcwang@xauat.edu.cn [School of Environmental and Municipal Engineering, Xi’an University of Architecture and Technology, Xi’an, Shaanxi Province, 710055 (China)

    2017-04-05

    Highlights: • A novel HOC process was firstly put forward to apply in wastewater reclamation. • Interactions between ozone and Al-based coagulants was found in the HOC process. • Ozonation can be catalyzed and enhanced by Al-based coagulants in the HOC process. • HOC process showed better organics removal than pre-ozonation-coagulation process. - Abstract: A novel hybrid ozonation-coagulation (HOC) process was developed for application in wastewater reclamation. In this process, ozonation and coagulation occurred simultaneously within a single unit. Compared with the conventional pre-ozonation-coagulation process, the HOC process exhibited much better performance in removing dissolved organic matters. In particular, the maximal organic matters removal efficiency was obtained at the ozone dosage of 1 mgO{sub 3}/mg DOC at each pH value (pH 5, 7 and 9). In order to interpret the mechanism of the HOC process, ozone decomposition was monitored. The results indicated that ozone decomposed much faster in the HOC process. Moreover, by using the reagent of O{sub 3}-resistant hydroxyl radical (·OH) probe compound, para-chlorobenzoic acid (pCBA), and electron paramagnetic resonance (EPR) analysis, it was observed that the HOC process generated higher content of ·OH compared with pre-ozonation process. This indicates that the ·OH oxidation reaction as the key step can be catalyzed and enhanced by Al-based coagulants and their hydrolyzed products in this developed process. Thus, based on the catalytic effects of Al-based coagulants on ozonation, the HOC process provides a promising alternative to the conventional technology for wastewater reclamation in terms of higher efficiency.

  20. Laser sintering of copper nanoparticles

    International Nuclear Information System (INIS)

    Zenou, Michael; Saar, Amir; Ermak, Oleg; Kotler, Zvi

    2014-01-01

    Copper nanoparticle (NP) inks serve as an attractive potential replacement to silver NP inks in functional printing applications. However their tendency to rapidly oxidize has so far limited their wider use. In this work we have studied the conditions for laser sintering of Cu-NP inks in ambient conditions while avoiding oxidation. We have determined the regime for stable, low-resistivity copper (< ×3 bulk resistivity value) generation in terms of laser irradiance and exposure duration and have indicated the limits on fast processing. The role of pre-drying conditions on sintering outcome has also been studied. A method, based on spectral reflectivity measurements, was used for non-contact monitoring of the sintering process evolution. It also indicates preferred spectral regions for sintering. Finally, we illustrated how selective laser sintering can generate high-quality, fine line (<5 µm wide) and dense copper circuits. (paper)

  1. Reincarnation of ancient links between coagulation and complement.

    Science.gov (United States)

    Conway, E M

    2015-06-01

    Throughout evolution, organisms have developed means to contain wounds by simultaneously limiting bleeding and eliminating pathogens and damaged host cells via the recruitment of innate defense mechanisms. Disease emerges when there is unchecked activation of innate immune and/or coagulation responses. A key component of innate immunity is the complement system. Concurrent excess activation of coagulation and complement - two major blood-borne proteolytic pathways - is evident in numerous diseases, including atherosclerosis, diabetes, venous thromboembolic disease, thrombotic microangiopathies, arthritis, cancer, and infectious diseases. Delineating the cross-talk between these two cascades will uncover novel therapeutic insights. © 2015 International Society on Thrombosis and Haemostasis.

  2. Models of current sintering

    Science.gov (United States)

    Angst, Sebastian; Engelke, Lukas; Winterer, Markus; Wolf, Dietrich E.

    2017-06-01

    Densification of (semi-)conducting particle agglomerates with the help of an electrical current is much faster and more energy efficient than traditional thermal sintering or powder compression. Therefore, this method becomes more and more common among experimentalists, engineers, and in industry. The mechanisms at work at the particle scale are highly complex because of the mutual feedback between current and pore structure. This paper extends previous modelling approaches in order to study mixtures of particles of two different materials. In addition to the delivery of Joule heat throughout the sample, especially in current bottlenecks, thermoelectric effects must be taken into account. They lead to segregation or spatial correlations in the particle arrangement. Various model extensions are possible and will be discussed.

  3. Production of pure sintered alumina

    International Nuclear Information System (INIS)

    Rocha, J.C. da; Huebner, H.W.

    1982-01-01

    With the aim of optimizing the sintering parameters, the strength of a large number of alumina samples was determined which were produced under widely varying sintering conditions and with different amounts of MgO content. The strength as a function of sintering time or temperature was found to go through a maximum. With increasing time, this maximum is shifted to lower temperatures, and with decreasing temperature to longer times. Data pairs of sintering times and temperatures which yeld the strength maximum were determined. The value of the strength at the maximum remains unchanged. The strength is high (= 400 MN/m 2 , at a grain size of 3 um and a porosity of 2 per cent) and comparable to foreign aluminas produced for commercial purposes, or even higher. The increase in the sintering time from 1 h to 16 h permits a reduction of the sintering temperature from 1600 to 1450 0 C without losing strength. The practical importance of this fact for a production of sintered alumina on a large scale is emphasized. (Author) [pt

  4. 21 CFR 864.5400 - Coagulation instrument.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Coagulation instrument. 864.5400 Section 864.5400....5400 Coagulation instrument. (a) Identification. A coagulation instrument is an automated or semiautomated device used to determine the onset of clot formation for in vitro coagulation studies. (b...

  5. Blood coagulation factors as inflammatory mediators

    NARCIS (Netherlands)

    Schoenmakers, Saskia H. H. F.; Reitsma, Pieter H.; Spek, C. Arnold

    2005-01-01

    After the first observations about blood coagulation by Hippocrates, it took until the early 1900s before the classic theory of blood coagulation was presented. As more and more other coagulation factors were discovered, the four-factor coagulation scheme became more complex, but better understood,

  6. Enhanced WWTP effluent organic matter removal in hybrid ozonation-coagulation (HOC) process catalyzed by Al-based coagulant.

    Science.gov (United States)

    Jin, Xin; Jin, Pengkang; Hou, Rui; Yang, Lei; Wang, Xiaochang C

    2017-04-05

    A novel hybrid ozonation-coagulation (HOC) process was developed for application in wastewater reclamation. In this process, ozonation and coagulation occurred simultaneously within a single unit. Compared with the conventional pre-ozonation-coagulation process, the HOC process exhibited much better performance in removing dissolved organic matters. In particular, the maximal organic matters removal efficiency was obtained at the ozone dosage of 1mgO 3 /mg DOC at each pH value (pH 5, 7 and 9). In order to interpret the mechanism of the HOC process, ozone decomposition was monitored. The results indicated that ozone decomposed much faster in the HOC process. Moreover, by using the reagent of O 3 -resistant hydroxyl radical (OH) probe compound, para-chlorobenzoic acid (pCBA), and electron paramagnetic resonance (EPR) analysis, it was observed that the HOC process generated higher content of OH compared with pre-ozonation process. This indicates that the OH oxidation reaction as the key step can be catalyzed and enhanced by Al-based coagulants and their hydrolyzed products in this developed process. Thus, based on the catalytic effects of Al-based coagulants on ozonation, the HOC process provides a promising alternative to the conventional technology for wastewater reclamation in terms of higher efficiency. Copyright © 2016 Elsevier B.V. All rights reserved.

  7. The sintering of nitrogen ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Hampshire, S.

    1986-01-01

    The mechanism of densification with oxide additives and the role of the ..cap alpha..-BETA phase transformation is investigated in a detailed kinetic study. Selected compositions in the Si-Al-O-N system are detailed, with and without additives. Although the work is mainly concerned with the identification of the mechanisms of sintering, some property measurements on a sintered BETA-sialon are reported and the feasibility of preparing pure ..cap alpha..-sialon phases is explored.

  8. Method of sintering ceramic materials

    Science.gov (United States)

    Holcombe, Cressie E.; Dykes, Norman L.

    1992-01-01

    A method for sintering ceramic materials is described. A ceramic article is coated with layers of protective coatings such as boron nitride, graphite foil, and niobium. The coated ceramic article is embedded in a container containing refractory metal oxide granules and placed within a microwave oven. The ceramic article is heated by microwave energy to a temperature sufficient to sinter the ceramic article to form a densified ceramic article having a density equal to or greater than 90% of theoretical density.

  9. Analysis and modeling of sintering of Sr-hexaferrite produced by PIM technology

    Directory of Open Access Journals (Sweden)

    Zlatkov B.S.

    2011-01-01

    Full Text Available The powder injection moulding (PIM technology is lately becoming more and more significant due to complex design possibilities and good repeatability. This technology requires optimization of all steps starting with material and binder, injection, debinding and sintering parameters. Sintering is one of the key links in this technology. The powder injection moulding process is specific as during feedstock injection powder particles mixed into the binder do not come into mechanical contact. Shrinkage during sintering of PIM samples is high. In this work we have analyzed and modeled the sintering process of isotropic PIM samples of Sr-hexaferrite. The Master Sintering Curve (MSC principle has been applied to analyze sintering of two types of PIM Sr-hexaferrite samples with completely removed binder and only the extraction step of the debinding procedure (thermal debinding proceeding simultaneously with sintering. Influence of the heating rate on resulting sample microstructures has also been analyzed. Influence of the sintering time and temperature was analyzed using three different phenomenological equations.

  10. Sintering of Multilayered Porous Structures: Part II – Experiments and Model Applications

    DEFF Research Database (Denmark)

    Ni, De Wei; Olevsky, Eugene; Esposito, Vincenzo

    2013-01-01

    for the determination of the shear viscosities ratio of the layer fully dense materials. This original technique enables the derivation of all the input parameters for the bilayer sintering modeling from one set of optical dilatometry measurements, including the conversion between real and specific times of sintering......, the layers’ relative sintering intensity, and the shear viscosities ratio of the layer fully dense materials. These optical dilatometry measurements are conducted simultaneously for each individual layer and for a symmetric trilayered porous structure based on the two layers utilized in the bilayered system...

  11. Hydrolysis of polyaluminum chloride prior to coagulation: Effects on coagulation behavior and implications for improving coagulation performance.

    Science.gov (United States)

    Zhang, Zhongguo; Wang, Jun; Liu, Dan; Li, Jiuyi; Wang, Xiaolin; Song, Boyu; Yue, Bing; Zhao, Kehui; Song, Yun

    2017-07-01

    The effects of polyaluminum chloride (PACl) hydrolysis prior to coagulation on both the coagulation zone and coagulation performance of a kaolin suspension were investigated by a novel jar test named the "reversed coagulation test". The tests showed that PACl hydrolysis prior to coagulation decreased the performance of charge neutralization coagulation in the case of short-time slow mixing (10min; G=15sec -1 ) and increased the optimal dosage for charge neutralization and sweep coagulation. Moreover, the hydrolysis time had insignificant effects on the size and zeta potential of PACl precipitates and the residual turbidity of the raw water. However, PACl hydrolysis prior to coagulation and the size of PACl precipitates had a negligible effect on the performance of sweep coagulation. The results imply that, in practice, preparing a PACl solution with deionized water, rather than tap water or the outlet water from a wastewater treatment unit, can significantly save PACl consumption and improve the performance of charge neutralization coagulation, while preparing the PACl solution with tap or outlet water would not affect the performance of sweep coagulation. In addition, the optimal rapid mixing intensity appears to be determined by a balance between the degree of coagulant hydrolysis before contacting the primary particles and the average size of flocs in the rapid mixing period. These results provide new insights into the role of PACl hydrolysis and will be useful for improving coagulation efficiency. Copyright © 2016. Published by Elsevier B.V.

  12. Ultrasonic measurement of milk coagulation time

    Science.gov (United States)

    Bakkali, F.; Moudden, A.; Faiz, B.; Amghar, A.; Maze, G.; Montero de Espinosa, F.; Akhnak, M.

    2001-12-01

    Using a pulse reflection technique an ultrasonic system has been developed to monitor in situ the coagulation process of rennetted milk. The velocity and attenuation of ultrasonic waves through coagulating milk were continuously monitored. The observed changes in ultrasonic velocity during coagulation were used to predict the coagulation time. The coagulation time is indicative of the transition from the enzymatic phase to the physicochemical phase. The determination of coagulation time has a decisive role in determining the qualities of the end product in cheesemaking.

  13. Coagulation assays and anticoagulant monitoring.

    Science.gov (United States)

    Funk, Dorothy M Adcock

    2012-01-01

    Anticoagulant therapy, including conventional agents and a variety of new oral, fast-acting drugs, is prescribed for millions of patients annually. Each anticoagulant varies in its effect on routine and specialty coagulation assays and each drug may require distinct laboratory assay(s) to measure drug concentration or activity. This review provides an overview of the assorted assays that can measure anticoagulant drug concentration or activity and includes key assay interferences. The effect of these conventional and new anticoagulant agents on specialty coagulation assays used to evaluate for bleeding or clotting disorders, and whether this impact is physiological or factitious, is included. Also provided is a short review of superwarfarin poisoning and features distinguishing this from warfarin overdose. Knowledge of clinically significant pearls and pitfalls pertinent to coagulation assays in relation to anticoagulant therapy are important to optimize patient care.

  14. Sintering diagrams of UO2

    International Nuclear Information System (INIS)

    Mohan, A.; Soni, N.C.; Moorthy, V.K.

    1979-01-01

    Ashby's method (see Acta Met., vol. 22, p. 275, 1974) of constructing sintering diagrams has been modified to obtain contribution diagrams directly from the computer. The interplay of sintering variables and mechanisms are studied and the factors that affect the participation of mechanisms in UO 2 are determined. By studying the physical properties, it emerges that the order of inaccuracies is small in most cases and do not affect the diagrams. On the other hand, even a 10% error in activation energies, which is quite plausible, would make a significant difference to the diagram. The main criticism of Ashby's approach is that the numerous properties and equations used, communicate their inaccuracies to the diagrams and make them unreliable. The present study has considerably reduced the number of factors that need to be refined to make the sintering diagrams more meaningful. (Auth.)

  15. Coagulation Status in Hidradenitis Suppurativa

    DEFF Research Database (Denmark)

    Miller, Iben Marie; Johansen, Maria Egede; Mogensen, Ulla B

    2015-01-01

    performed a hospital- and population-based cross-sectional study investigating the coagulation status (thrombocytes, mean platelet volume [MPV], international normalized ratio [INR] and activated partial thromboplastin time [APTT]). RESULTS: 32 hospital HS subjects, 430 population HS subjects and 20.......3432). CONCLUSION: We did not find an association between HS and prothrombotic/hypercoagulable status. Thus, thrombocytes may not be activated in HS. Furthermore, INR may not be affected in HS, suggesting that intrinsic and vitamin K-dependent coagulation factors appear unaffected....

  16. Recycling of mill scale in sintering process

    Directory of Open Access Journals (Sweden)

    El-Hussiny N.A.

    2011-01-01

    Full Text Available This investigation deals with the effect of replacing some amount of Baharia high barite iron ore concentrate by mill scale waste which was characterized by high iron oxide content on the parameters of the sintering process., and investigation the effect of different amount of coke breeze added on sintering process parameters when using 5% mill scale waste with 95% iron ore concentrate. The results of this work show that, replacement of iron ore concentrate with mill scale increases the amount of ready made sinter, sinter strength and productivity of the sinter machine and productivity at blast furnace yard. Also, the increase of coke breeze leads to an increase the ready made sinter and productivity of the sintering machine at blast furnace yard. The productivity of the sintering machine after 5% decreased slightly due to the decrease of vertical velocity.

  17. Phosphorus containing sintered alloys (review)

    International Nuclear Information System (INIS)

    Muchnik, S.V.

    1984-01-01

    Phosphorus additives are considered for their effect on the properties of sintered alloys of different applications: structural, antifriction, friction, magnetic, hard, superhard, heavy etc. Data are presented on compositions and properties of phosphorus-containing materials produced by the powder metallurgy method. Phosphorus is shown to be an effective activator of sintering in some cases. When its concentration in the material is optimal it imparts the material such properties as strength, viscosity, hardness, wear resistance. Problems concerning powder metallurgy of amorphous phosphorus-containing alloys are reported

  18. Sintering of ultra high molecular weight polyethylene

    Indian Academy of Sciences (India)

    ... involves compaction of polymeric powder under pressure and sintering of the preforms at temperature above its melting point. In this study, we report our results on compaction and sintering behaviour of two grades of UHMWPE with reference to the powder morphology, sintering temperatures and strength development.

  19. The interplay between platelets and coagulation

    NARCIS (Netherlands)

    Weeterings, C.

    2009-01-01

    Platelet activation and blood coagulation are two processes often studied separately, but which cannot be seen independently from each other. Platelets play a pivotal role in coagulation, not only by providing negatively charged phospholipids, but also in localizing the coagulation process from a

  20. Master Sintering Surface: A practical approach to its construction and utilization for Spark Plasma Sintering prediction

    Directory of Open Access Journals (Sweden)

    Pouchly V.

    2012-01-01

    Full Text Available The sintering is a complex thermally activated process, thus any prediction of sintering behaviour is very welcome not only for industrial purposes. Presented paper shows the possibility of densification prediction based on concept of Master Sintering Surface (MSS for pressure assisted Spark Plasma Sintering (SPS. User friendly software for evaluation of the MSS is presented. The concept was used for densification prediction of alumina ceramics sintered by SPS.

  1. Sintering additives for zirconia ceramics

    International Nuclear Information System (INIS)

    Wu, S.

    1986-01-01

    This book is an overview of sintering science and its application to zirconia materials including CaO, MgO, and Y/sub 2/O/sub 3/-CeO/sub 2/ doped materials. This book is a reference for first-time exposure to zirconia materials technology, particularly densification

  2. Sintering additives for zirconia ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Wu, S.

    1986-01-01

    This book is an overview of sintering science and its application to zirconia materials including CaO, MgO, and Y/sub 2/O/sub 3/-CeO/sub 2/ doped materials. This book is a reference for first-time exposure to zirconia materials technology, particularly densification.

  3. No effect of isolated long-term supine immobilization or profound prolonged hypoxia on blood coagulation.

    Science.gov (United States)

    Venemans-Jellema, A; Schreijer, A J M; Le Cessie, S; Emmerich, J; Rosendaal, F R; Cannegieter, S C

    2014-06-01

    Long-distance air travel is associated with an increased risk of venous thrombosis. The most obvious factor that can explain air travel-related thrombosis is prolonged seated immobilization. In addition, hypobaric hypoxia has been shown to affect coagulation, and the lowered atmospheric pressures present in the cabin during the flight may therefore play an etiologic role. Because immobilization and hypoxic conditions are usually present simultaneously in airplanes or hypobaric chambers, their separate effects on the coagulation system or on thrombosis risk have not been studied extensively. To investigate the separate effects of long-term immobilization and profound prolonged hypoxia on blood coagulation. We performed two studies in collaboration with European Space Agency/European Space Research and Technology Centre. In the first study, 24 healthy, non-smoking, adult women underwent 60 days of -6° head-down bed rest. In the second study, we took blood samples from 25 healthy men who participated during their stay in the Concordia station in Antarctica, where, due to the atmospheric conditions, continuous severe hypobaric hypoxia is present. In both studies, we measured markers of blood coagulation at baseline and at several time points during the exposures. We observed no increase in coagulation markers during immobilization or in the hypobaric environment, compared with baseline measurements. Our results indicate that neither immobilization nor hypoxia per se affects blood coagulation. These results implicate that a combination of risk factors is necessary to induce the coagulation system during air travel. © 2014 International Society on Thrombosis and Haemostasis.

  4. Monitoring of temperature profiles and surface morphologies during laser sintering of alumina ceramics

    Directory of Open Access Journals (Sweden)

    Bin Qian

    2014-06-01

    Full Text Available Additive manufacturing of alumina by laser is a delicate process and small changes of processing parameters might cause less controlled and understood consequences. The real-time monitoring of temperature profiles, spectrum profiles and surface morphologies were evaluated in off-axial set-up for controlling the laser sintering of alumina ceramics. The real-time spectrometer and pyrometer were used for rapid monitoring of the thermal stability during the laser sintering process. An active illumination imaging system successfully recorded the high temperature melt pool and surrounding area simultaneously. The captured images also showed how the defects form and progress during the laser sintering process. All of these real-time monitoring methods have shown a great potential for on-line quality control during laser sintering of ceramics.

  5. Strain-enhanced sintering of iron powders

    Energy Technology Data Exchange (ETDEWEB)

    Amador, D.R.; Torralba, J.M. [Universidad Carlos III de Madrid, Departamento de Ciencias de Materiales e Ingenieria Metalurgica, Leganes, Madrid (Spain); Monge, M.A.; Pareja, R. [Universidad Carlos III de Madrid, Departamento de Fisica, Madrid (Spain)

    2005-02-01

    Sintering of ball-milled and un-milled Fe powders has been investigated using dilatometry, X-ray, density, and positron annihilation techniques. A considerable sintering enhancement is found in milled powders showing apparent activation energies that range between 0.44 and 0.80 eV/at. The positron annihilation results, combined with the evolution of the shrinkage rate with sintering temperature, indicate generation of lattice defects during the sintering process of milled and un-milled powders. The sintering enhancement is attributed to pipe diffusion along the core of moving dislocations in the presence of the vacancy excess produced by plastic deformation. Positron annihilation results do not reveal the presence of sintering-induced defects in un-milled powders sintered above 1200 K, the apparent activation energy being in good agreement with that for grain-boundary diffusion in {gamma}-Fe. (orig.)

  6. Sintered wire cesium dispenser photocathode

    Science.gov (United States)

    Montgomery, Eric J; Ives, R. Lawrence; Falce, Louis R

    2014-03-04

    A photoelectric cathode has a work function lowering material such as cesium placed into an enclosure which couples a thermal energy from a heater to the work function lowering material. The enclosure directs the work function lowering material in vapor form through a low diffusion layer, through a free space layer, and through a uniform porosity layer, one side of which also forms a photoelectric cathode surface. The low diffusion layer may be formed from sintered powdered metal, such as tungsten, and the uniform porosity layer may be formed from wires which are sintered together to form pores between the wires which are continuous from the a back surface to a front surface which is also the photoelectric surface.

  7. Study of nano-metric silicon carbide powder sintering. Application to fibers processing

    International Nuclear Information System (INIS)

    Malinge, A.

    2011-01-01

    Silicon carbide ceramic matrix composites (SiCf/SiCm) are of interest for high temperature applications in aerospace or nuclear components for their relatively high thermal conductivity and low activation under neutron irradiation. While most of silicon carbide fibers are obtained through the pyrolysis of a poly-carbo-silane precursor, sintering of silicon carbide nano-powders seems to be a promising route to explore. For this reason, pressureless sintering of SiC has been studied. Following the identification of appropriate sintering aids for the densification, optimization of the microstructure has been achieved through (i) the analysis of the influence of operating parameters and (ii) the control of the SiC β a SiC α phase transition. Green fibers have been obtained by two different processes involving the extrusion of SiC powder dispersion in polymer solution or the coagulation of a water-soluble polymer containing ceramic particles. Sintering of these green fibers led to fibers of around fifty microns in diameter. (author) [fr

  8. Nuclear tracks in sinterized gemstones

    International Nuclear Information System (INIS)

    Espinosa, G.; Rodriguez, L.V.; Golzarri, J.I.; Castano, V.M.

    1993-01-01

    The responses of sinterized gemstones to alpha particles attempt analyzed with the objective of finding new materials for SSNTD, and also to understand their interaction with radiation and the formation of tracks. In this work we present the results of the characterization of these materials as SSNTD. The micro structural changes observed by electron microscopy. The preparation, etching solution concentration, etching time and effects of temperature are discussed. (Author)

  9. Microwave sintering of ceramic materials

    Science.gov (United States)

    Karayannis, V. G.

    2016-11-01

    In the present study, the potential of microwave irradiation as an innovative energy- efficient alternative to conventional heating technologies in ceramic manufacturing is reviewed, addressing the advantages/disadvantages, while also commenting on future applications of possible commercial interest. Ceramic materials have been extensively studied and used due to several advantages they exhibit. Sintering ceramics using microwave radiation, a novel technology widely employed in various fields, can be an efficient, economic and environmentally-friendlier approach, to improve the consolidation efficiency and reduce the processing cycle-time, in order to attain substantial energy and cost savings. Microwave sintering provides efficient internal heating, as energy is supplied directly and penetrates the material. Since energy transfer occurs at a molecular level, heat is generated throughout the material, thus avoiding significant temperature gradients between the surface and the interior, which are frequently encountered at high heating rates upon conventional sintering. Thus, rapid, volumetric and uniform heating of various raw materials and secondary resources for ceramic production is possible, with limited grain coarsening, leading to accelerated densification, and uniform and fine-grained microstructures, with enhanced mechanical performance. This is particularly important for manufacturing large-size ceramic products of quality, and also for specialty ceramic materials such as bioceramics and electroceramics. Critical parameters for the process optimization, including the electromagnetic field distribution, microwave-material interaction, heat transfer mechanisms and material transformations, should be taken into consideration.

  10. Characterization and properties of sintered WC–Co and WC–Ni–Fe hard metal alloys

    International Nuclear Information System (INIS)

    Chang, Shih-Hsien; Chen, Song-Ling

    2014-01-01

    Highlights: • WC–Ni–Fe alloy sintered at 1400 °C had the highest hardness (HRA 85.3 ± 0.5). • The optimal WC–Ni–Fe sintered alloy possessed the highest TRS value (2524.5 ± 1.0 MPa). • The fracture toughness of the sintered WC–Ni–Fe alloys is mainly provided by the Ni–Fe binders. • WC–Ni–Fe sintered alloy possessed the highest fracture toughness of K IC (15.1 MPa m 1/2 ). • The WC–Ni–Fe sintered alloy had the much better corrosion resistance in 0.15 M HCl solution. -- Abstract: The aim of this study is to explore two different tungsten carbide binders (Co and Ni–Fe) and then impose various sintering temperature treatments. Experimental results show that the optimal sintering temperatures for WC–Co and WC–Ni–Fe hard metal alloys are 1350 °C and 1400 °C for 1 h, respectively. Meanwhile, the WC–Co and WC–Ni–Fe alloys undergo a well liquid-phase sintering and, thus, exhibit excellent mechanical properties. In addition, the sintered WC–Co and WC–Ni–Fe alloys show that when the relative density reached 99.76% and 99.68%, the hardness was enhanced to HRA 84.4 ± 0.5 and 85.3 ± 0.5, and the TRS increased to 2471.2 ± 1.0 and 2524.5 ± 1.0 MPa, respectively. Moreover, the corrosion test results show that the WC–Ni–Fe alloy sintered at 1400 °C had the lowest corrosion current (I corr ) of 1.11 × 10 −5 A cm −2 and the highest polarization resistance (R p ) of 2464.61 Ω cm 2 in 0.15 M HCl solution. Simultaneously, the fracture toughness of K IC increased to 15.1 MPa m 1/2 . Compared with sintered WC–Co alloys, the sintered WC–Ni–Fe hard metal alloys possessed much better corrosion resistance and mechanical properties

  11. Characterization and properties of sintered WC–Co and WC–Ni–Fe hard metal alloys

    Energy Technology Data Exchange (ETDEWEB)

    Chang, Shih-Hsien, E-mail: changsh@ntut.edu.tw; Chen, Song-Ling

    2014-02-05

    Highlights: • WC–Ni–Fe alloy sintered at 1400 °C had the highest hardness (HRA 85.3 ± 0.5). • The optimal WC–Ni–Fe sintered alloy possessed the highest TRS value (2524.5 ± 1.0 MPa). • The fracture toughness of the sintered WC–Ni–Fe alloys is mainly provided by the Ni–Fe binders. • WC–Ni–Fe sintered alloy possessed the highest fracture toughness of K{sub IC} (15.1 MPa m{sup 1/2}). • The WC–Ni–Fe sintered alloy had the much better corrosion resistance in 0.15 M HCl solution. -- Abstract: The aim of this study is to explore two different tungsten carbide binders (Co and Ni–Fe) and then impose various sintering temperature treatments. Experimental results show that the optimal sintering temperatures for WC–Co and WC–Ni–Fe hard metal alloys are 1350 °C and 1400 °C for 1 h, respectively. Meanwhile, the WC–Co and WC–Ni–Fe alloys undergo a well liquid-phase sintering and, thus, exhibit excellent mechanical properties. In addition, the sintered WC–Co and WC–Ni–Fe alloys show that when the relative density reached 99.76% and 99.68%, the hardness was enhanced to HRA 84.4 ± 0.5 and 85.3 ± 0.5, and the TRS increased to 2471.2 ± 1.0 and 2524.5 ± 1.0 MPa, respectively. Moreover, the corrosion test results show that the WC–Ni–Fe alloy sintered at 1400 °C had the lowest corrosion current (I{sub corr}) of 1.11 × 10{sup −5} A cm{sup −2} and the highest polarization resistance (R{sub p}) of 2464.61 Ω cm{sup 2} in 0.15 M HCl solution. Simultaneously, the fracture toughness of K{sub IC} increased to 15.1 MPa m{sup 1/2}. Compared with sintered WC–Co alloys, the sintered WC–Ni–Fe hard metal alloys possessed much better corrosion resistance and mechanical properties.

  12. Titanium Powder Sintering in a Graphite Furnace and Mechanical Properties of Sintered Parts

    OpenAIRE

    Changzhou Yu; Peng Cao; Mark Ian Jones

    2017-01-01

    Recent accreditation of titanium powder products for commercial aircraft applications marks a milestone in titanium powder metallurgy. Currently, powder metallurgical titanium production primarily relies on vacuum sintering. This work reported on the feasibility of powder sintering in a non-vacuum furnace and the tensile properties of the as-sintered Ti. Specifically, we investigated atmospheric sintering of commercially pure (C.P.) titanium in a graphite furnace backfilled with argon and stu...

  13. Production of sintered alumina from powder; optimization of the sinterized parameters for the maximum mechanical resistence

    International Nuclear Information System (INIS)

    Rocha, J.C. da.

    1981-02-01

    Pure, sinterized alumina and the optimization of the parameters of sinterization in order to obtain the highest mechanical resistence are discussed. Test materials are sinterized from a fine powder of pure alumina (Al 2 O 3 ), α phase, at different temperatures and times, in air. The microstructures are analysed concerning porosity and grain size. Depending on the temperature or the time of sinterization, there is a maximum for the mechanical resistence. (A.R.H.) [pt

  14. Fundamental research on sintering technology with super deep bed achieving energy saving and reduction of emissions

    International Nuclear Information System (INIS)

    Hongliang Han; Shengli Wu; Gensheng Feng; Luowen Ma; Weizhong Jiang

    2012-01-01

    In the general frame of energy saving, environment protection and the concept of circular economy, the fundamental research on the sintering technology with super deep bed, achieving energy saving and emission reduction, was carried out. At first, the characteristics of the process and exhaust emission in the sintering with super deep bed was mastered through the study of the influence of different bed depths on the sintering process. Then, considering the bed permeability and the fuel combustion, their influence on the sinter yield and quality, their potential for energy saving and emission reduction was studied. The results show that the improvement of the bed permeability and of the fuel combustibility respectively and simultaneously, leads to an improvement of the sintering technical indices, to energy saving and emission reduction in the condition of super deep bed. At 1000 mm bed depth, and taking the appropriate countermeasure, it is possible to decrease the solid fuel consumption and the emission of CO 2 , SO 2 , NO x by 10.08%, 11.20%, 22.62% and 25.86% respectively; and at 700 mm bed depth, it is possible to reduce the solid fuel consumption and the emission of CO 2 , SO 2 , NO x by 20.71%, 22.01%, 58.86% and 13.13% respectively. This research provides the theoretical and technical basis for the new technology of sintering with super deep bed, achieving energy saving and reduction of emission. (authors)

  15. Alternative sintering methods compared to conventional thermal sintering for inkjet printed silver nanoparticle ink

    NARCIS (Netherlands)

    Niittynen, J.; Abbel, R.; Mäntysalo, M.; Perelaer, J.; Schubert, U.S.; Lupo, D.

    2014-01-01

    In this contribution several alternative sintering methods are compared to traditional thermal sintering as high temperature and long process time of thermal sintering are increasing the costs of inkjet-printing and preventing the use of this technology in large scale manufacturing. Alternative

  16. Protocol for Ultralow-Temperature Ceramic Sintering: An Integration of Nanotechnology and the Cold Sintering Process.

    Science.gov (United States)

    Guo, Hanzheng; Baker, Amanda; Guo, Jing; Randall, Clive A

    2016-11-22

    The sintering process is an essential step in taking particulate materials into dense ceramic materials. Although a number of sintering techniques have emerged over the past few years, the sintering process is still performed at high temperatures. Here we establish a protocol to achieve dense ceramic solids at extremely low temperatures (sustainable manufacturing practices.

  17. Coagulation factor Xa signaling : the link between coagulation and inflammatory bowel disease?

    NARCIS (Netherlands)

    Borensztajn, Keren; Peppelenbosch, Maikel P.; Spek, C. Arnold

    Inflammatory bowel disease (IBD) is characterized by activation of the coagulation cascade and it has long been suspected that coagulation is an essential component of this still largely idiopathic group of diseases. The realization that coagulation factors are not only passive mediators in the

  18. Coagulation factor Xa signaling: the link between coagulation and inflammatory bowel disease?

    NARCIS (Netherlands)

    Borensztajn, Keren; Peppelenbosch, Maikel P.; Spek, C. Arnold

    2009-01-01

    Inflammatory bowel disease (IBD) is characterized by activation of the coagulation cascade and it has long been suspected that coagulation is an essential component of this still largely idiopathic group of diseases. The realization that coagulation factors are not only passive mediators in the

  19. SYSTEM OF PRECISE DOSING OF COAGULANT IN THE PULVERIZING AERATOR POWERED BY WIND USING FUZZY LOGIC

    Directory of Open Access Journals (Sweden)

    Andrzej Osuch

    2017-06-01

    Full Text Available One of the methods used to support land restoration lakes is the method of pulverizing aeration. Use of aerators powered exclusively by wind improves the condition of reservoirs, while not compromising the environment. The pulverizing aeration process drive is windy on the water aeration zone near bottom, while removing harmful gases anaerobic metabolism. Aerators of this type due to the unique method of operation also enable dosing of inactivation coagulants with oxygenated water to the depths of the lake. Mileage coagulant dosing can be made dependent on the speed of the wind, which has an impact on the performance of his work, because with the increase of wind speed dispensing valve coagulants should be stronger open. One of the methods for assessing the state of lakes is to measure water transparency. The softer visibility, the most likely state of the water is better. Dosage of coagulant so you can make the transparency of the water. Similarly, with increasing transparency water dispensing valve should be more covered up. Control of the drain valve dispenser coagulant can be simultaneously dependent on two factors. The study was designed method of control drain valve dispenser coagulant using fuzzy inference.

  20. Intravascular blood coagulation after irradiation

    International Nuclear Information System (INIS)

    Sushkevich, G.N.

    1981-01-01

    The problems of activation of intravascular blood coagulation (JVBC) at different stages after irradiation, are considered. JVBC peculiarities (disseminated intravascular syndrome (DIV) or thrombo hemorrhagic syndrome) are investigated. Literature on alterations which take place in the organism under effect of ionizing irradiation is analyzed. This analysis proves the characteristic features of thrombinogenesis activation and development of DIV syndrome not only in the early post-radiation period, but in the middle of radiation disease, as well. It is also shown that ionizing radiation activizes the hemocoagulation process and causes IVBC in the case of both local and general irradiation [ru

  1. Master sintering curves of two different alumina powder compacts

    Directory of Open Access Journals (Sweden)

    Vaclav Pouchly

    2009-12-01

    Full Text Available Concept of Master Sintering Curve is a strong tool for optimizing sintering schedule. The sintering behaviour can be predicted, and sintering activation energy can be calculated with the help of few dilatometric measurements. In this paper an automatic procedure was used to calculate Master Sintering Curves of two different alumina compacts. The sintering activation energies were determined as 640 kJ/mol for alumina with particle size of 240 nm, respective 770 kJ/mol for alumina with particle size of 110 nm. The possibility to predict sintering behaviour with the help of Master Sintering Curve was verified.

  2. Coagulation and fibrinolysis during laparoscopic cholecystectomy

    DEFF Research Database (Denmark)

    Rahr, H B; Fabrin, K; Larsen, J F

    1999-01-01

    Laparoscopic surgery appears to be less traumatic to the patient than open surgery, but its influence upon coagulation and fibrinolysis is incompletely elucidated. Our aim was to measure markers of coagulation and fibrinolysis before, during. and after laparoscopic cholecystectomy (LC). Blood...

  3. On coagulation process in meteor trails

    International Nuclear Information System (INIS)

    Bergkhanov, M.

    1988-01-01

    Structure of the meteors processes of collisions of paricles formd after interaction of meteoric matter with the Earth atmosphere are shortly described. Equation describing coagulation in meteor trails is obtained. Primary and secondary particles of meteor nature, representing the source of polydisperse aerosol, exist in meteor zone. Coagulation in meteor trails can be referred to Brownian one

  4. Sintering characteristics of nano-ceramic coatings

    NARCIS (Netherlands)

    de Hosson, J.T.M.; Popma, R.

    2003-01-01

    This paper concentrates on sintering characteristics of nano-sized ceramic SiO2 particles. The sintering process is studied as a function of temperature using a conventional furnace and using a laser beam. The underlying idea is to combine the nanoceramic sol-gel concept with inkjet technology and

  5. Mechanical characteristics of microwave sintered silicon carbide

    Indian Academy of Sciences (India)

    In firing of products by conventionally sintered process, SiC grain gets oxidized producing SiO2 (∼ 32 wt%) and deteriorates the quality of the product substantially. Partially sintered silicon carbide by such a method is a useful material for a varieties of applications ranging from kiln furniture to membrane material.

  6. Kinetic analysis of boron carbide sintering

    International Nuclear Information System (INIS)

    Borchert, W.; Kerler, A.R.

    1975-01-01

    The kinetics of the sintering of boron carbide were investigated by shrinkage measurements with a high-temperature dilatometer under argon atmosphere in dependence on temperature, grain size, and pressure. The activation energies and the reaction mechanisms of the different stages of sintering were determined. (orig.) [de

  7. Electro sinter forging of titanium disks

    DEFF Research Database (Denmark)

    Cannella, Emanuele; Nielsen, Chris Valentin; Bay, Niels Oluf

    Electro sinter forging (ESF) is a new sintering process based on the principle of electrical Joule heating. In the present work, middle frequency direct current (MFDC) was flowing through the powder compact, which was under mechanical pressure. The main parameters are the high electrical current,...

  8. Sintering of ultra high molecular weight polyethylene

    Indian Academy of Sciences (India)

    Abstract. Ultra high molecular weight polyethylene (UHMWPE) is a high performance polymer having low coefficient of friction, good abrasion resistance, good chemical ... In this study, we report our results on compaction and sintering behaviour of two grades of UHMWPE with reference to the powder morphology, sintering ...

  9. Sintered-to-size FBR fuel

    International Nuclear Information System (INIS)

    Rasmussen, D.E.; Schaus, P.S.

    1984-04-01

    Fabrication of sintered-to-size PuO 2 -UO 2 fuel pellets was completed for testing of proposed FBR product specifications. Approximately 6000 pellets were fabricated to two nominal diameters and two densities by cold pressing and sintering to size. Process control and correlation between test and production batches are discussed

  10. Sintering of zirconia in high-pressure

    International Nuclear Information System (INIS)

    Kunrath, A.O.; Strohaecker, T.R.; Pereira, A.S.; Jornada, J.A.H. da; Piermarini, G.J.

    1989-01-01

    A systematic study about the sintering of zirconia hyperfines powders in high-pressure is presented. The differents conditions effect of sintering in microstructure and in hardness and tenacity properties of zirconia samples with a very fine grain is also studied. (C.G.C.) [pt

  11. Modeling the microstructural evolution during constrained sintering

    DEFF Research Database (Denmark)

    Bjørk, Rasmus; Frandsen, Henrik Lund; Tikare, V.

    A numerical model able to simulate solid state constrained sintering of a powder compact is presented. The model couples an existing kinetic Monte Carlo (kMC) model for free sintering with a finite element (FE) method for calculating stresses on a microstructural level. The microstructural respon...

  12. Modeling the Microstructural Evolution During Constrained Sintering

    DEFF Research Database (Denmark)

    Bjørk, Rasmus; Frandsen, Henrik Lund; Pryds, Nini

    2015-01-01

    A numerical model able to simulate solid-state constrained sintering is presented. The model couples an existing kinetic Monte Carlo model for free sintering with a finite element model (FEM) for calculating stresses on a microstructural level. The microstructural response to the local stress as ...

  13. Mechanical characteristics of microwave sintered silicon carbide

    Indian Academy of Sciences (India)

    Unknown

    Central Glass and Ceramic Research Institute, Kolkata 700 032, India. Abstract. The present work deals with the sintering of ... recently become an attractive area of research and deve- lopment. The major advantages of ... without the usage of sintering aids (Lee and Case 1999;. Goldstein et al 1999). Several studies have ...

  14. THE POLARIZING EFFECTS IN SINTERED KAOLIN

    African Journals Online (AJOL)

    compacted and sintered density of the ceramic have been studied, and a density — pressure relationship for before- and after-sintering conditions obtained. INTRODUCTION. Ceramics have been known to mankind for thousands of years, and have been used in construction materials. In many applications, ceramics have.

  15. The Influence of Sintering Temperature of Reactive Sintered (Ti, MoC-Ni Cermets

    Directory of Open Access Journals (Sweden)

    Marek Jõeleht

    2015-09-01

    Full Text Available Titanium-molybdenum carbide nickel cermets ((Ti, MoC-Ni were produced using high energy milling and reactive sintering process. Compared to conventional TiC-NiMo cermet sintering the parameters for reactive sintered cermets vary since additional processes are present such as carbide synthesis. Therefore, it is essential to acquire information about the suitable sintering regime for reactive sintered cermets. One of the key parameters is the final sintering temperature when the liquid binder Ni forms the final matrix and vacancies inside the material are removed. The influence of the final sintering temperature is analyzed by scanning electron microscopy. Mechanical properties of the material are characterized by transverse rupture strength, hardness and fracture toughness.DOI: http://dx.doi.org/10.5755/j01.ms.21.3.7179

  16. Investigation of coagulation activity of natural coagulants from seeds of different leguminose species

    Directory of Open Access Journals (Sweden)

    Šćiban Marina B.

    2005-01-01

    Full Text Available The ability of seeds of plants: Phaseolus vulgaris, Robinia pseudoacacia Ceratonia siliqua and Amorpha fruticosa, to act as natural coagulants was tested using synthetic turbid water. This water was prepared by adding kaolin into tap water, just before the test. Active components were extracted from ground seeds with distilled water. The coagulation ability of this extract was assessed by the use of standard jar test measurements in water with various initial turbidity. Investigation of these natural coagulants was confirmed their positive coagulation activity. Of all plants that have been examined, the seed extract from Ceratonia siliqua appeared to be one of the most effective coagulants for water treatment. A dose of 20 mg/l of this coagulant resulted in 100% coagulation activity for clarification of water with 17.5 NTU initial turbidity.

  17. Sintered ceramics having controlled density and porosity

    International Nuclear Information System (INIS)

    Brassfield, H.C.; DeHollander, W.R.; Nivas, Y.

    1980-01-01

    A new method was developed for sintering ceramic uranium dioxide powders, in which ammonium oxalate is admixed with the powder prior to being pressed into a cylindrical green body, so that the end-point density of the final nuclear-reactor fuel product can be controlled. When the green body is heated, the ammonium oxalate decomposes and leaves discrete porosity in the sintered body, which corresponds to the ammonium oxalate regions in the green body. Thus the end-point density of the sintered body is a function of the amount of ammonium oxalate added. The final density of the sintered product is about 90-97% of the theoretical. The addition of ammonium oxalate also allows control of the pore size and distribution throughout the fuel. The process leaves substantially no impurities in the sintered strucuture. (DN)

  18. The Use of Tannins from Turkish Acorns (Valonia) in Water Treatment as a Coagulant and Coagulant Aid

    OpenAIRE

    ŞENGİL, Mahmut ÖZACAR and İ. Ayhan

    2002-01-01

    Coagulants play an important role in the treatment of water and wastewater and in the treatment and disposal of sludge. Aluminum sulfate, alum, is the common chemical coagulant used in the coagulation process. Recently polymers have been utilized in coagulation/flocculation processes for water purification. In this study, a natural indigenous coagulant is suggested as a substitute for alum or as an aid for alum. The coagulant characteristics of the tannins obtained from valonia were examine...

  19. Titanium Powder Sintering in a Graphite Furnace and Mechanical Properties of Sintered Parts

    Directory of Open Access Journals (Sweden)

    Changzhou Yu

    2017-02-01

    Full Text Available Recent accreditation of titanium powder products for commercial aircraft applications marks a milestone in titanium powder metallurgy. Currently, powder metallurgical titanium production primarily relies on vacuum sintering. This work reported on the feasibility of powder sintering in a non-vacuum furnace and the tensile properties of the as-sintered Ti. Specifically, we investigated atmospheric sintering of commercially pure (C.P. titanium in a graphite furnace backfilled with argon and studied the effects of common contaminants (C, O, N on sintering densification of titanium. It is found that on the surface of the as-sintered titanium, a severely contaminated porous scale was formed and identified as titanium oxycarbonitride. Despite the porous surface, the sintered density in the sample interiors increased with increasing sintering temperature and holding time. Tensile specimens cut from different positions within a large sintered cylinder reveal different tensile properties, strongly dependent on the impurity level mainly carbon and oxygen. Depending on where the specimen is taken from the sintered compact, ultimate tensile strength varied from 300 to 580 MPa. An average tensile elongation of 5% to 7% was observed. Largely depending on the interstitial contents, the fracture modes from typical brittle intergranular fracture to typical ductile fracture.

  20. Enhanced coagulation for high alkalinity and micro-polluted water: the third way through coagulant optimization.

    Science.gov (United States)

    Yan, Mingquan; Wang, Dongsheng; Qu, Jiuhui; Ni, Jinren; Chow, Christopher W K

    2008-04-01

    Conventional coagulation is not an effective treatment option to remove natural organic matter (NOM) in water with high alkalinity/pH. For this type of water, enhanced coagulation is currently proposed as one of the available treatment options and is implemented by acidifying the raw water and applying increased doses of hydrolyzing coagulants. Both of these methods have some disadvantages such as increasing the corrosive tendency of water and increasing cost of treatment. In this paper, an improved version of enhanced coagulation through coagulant optimization to treat this kind of water is demonstrated. A novel coagulant, a composite polyaluminum chloride (HPAC), was developed with both the advantages of polyaluminum chloride (PACl) and the additive coagulant aids: PACl contains significant amounts of highly charged and stable polynuclear aluminum hydrolysis products, which is less affected by the pH of the raw water than traditional coagulants (alum and ferric salts); the additives can enhance both the charge neutralization and bridging abilities of PACl. HPAC exhibited 30% more efficiency than alum and ferric salts in dissolved organic carbon (DOC) removal and was very effective in turbidity removal. This result was confirmed by pilot-scale testing, where particles and organic matter were removed synergistically with HPAC as coagulant by sequential water treatment steps including pre-ozonation, coagulation, flotation and sand filtration.

  1. Thermodynamics and mechanisms of sintering

    International Nuclear Information System (INIS)

    Pask, J.A.

    1978-10-01

    A phenomenological overview and exploration of the thermodynamic and geometric factors play a role in the process of densification of model compact systems consisting of crystalline spheres of uniform size in regular and irregular packing that form grain boundaries at every contact point. A further assumption is the presence of isotropic surface and grain boundary energies. Although such systems are unrealistic in comparison with normal powder compacts, their potential sintering behavior can be analyzed and provided with a limiting set of behavior conditions which can be looked upon as one boundary condition. This approach is logically realistic since it is easier to understand and provide a basis for understanding the more complex real powder systems

  2. Melting and Sintering of Ashes

    DEFF Research Database (Denmark)

    Hansen, Lone Aslaug

    1997-01-01

    , the biggest deviations being found for salt rich (i.e. straw derived) ashes.A simple model assuming proportionality between fly ash fusion and deposit formation was found to be capable of ranking deposition rates for the different straw derived fly ashes, whereas for the fly ashes from coal/straw co......-firing, the model only had a qualitative agreement with the measured ash deposit formation rates.Sintering measurements were carried out by means of compression strength testing of ash pellets. This method showed to not be applicable for the salt rich fly ash derived from straw combustion. For the fly ashes...... have been employed in a simple model for prediction of ash deposit formation, the results of which have been compared to ash deposition formation rates measured at the respective boilers.The ash fusion results were found to directly reflect the ash compositional data:a) Fly ashes and deposits from...

  3. Science of sintering and its future

    International Nuclear Information System (INIS)

    Ristic, M.M.

    1975-01-01

    Some new books published by M.Yu. Baljshin, V.A. Ivensen, V.V. Skorohod and others are characterized by the wish to give a complete approach to the problems of sintering theory. Bearing just this in mind while writing the book ''An Essay on the Generalization of Sintering Theory'' (G.V.Samsonov, M.M. Ristic with the collaborators) an idea was born: to ask the most eminent scientists in this field to present their own opinions on the theme ''The Science of Sintering and Modern Views on its Future''. There were formed 18 questions, given in the appendix to be answered. The received answers were presented in 10 chapters of this book. The fourth part of the book consists of papers of eminent scientists engaged in the field of sintering science (some of which were published here for the first time). This material is published in the book with the consent of the authors and these original contributions provide a more profound knowledge of sintering. The initial idea, that the book should have a monograph character and in which the answers would serve as some data on the latest notions of the science of sintering, was somewhat changed since the original opinions of individual scientists are given in the book and these, are sometimes very contradictory. This, in fact, gives the book a special charm because the unsolved problems in the science of sintering are most evidently stressed in this way

  4. Preparation and sintering of Zr(C,N,O) phases

    International Nuclear Information System (INIS)

    Tamborenea, S.; Mazzoni, A.D.; Aglietti, E.F.

    2003-01-01

    The Zr(C,O,N) compounds form a great mono-phase zone belonging to the pseudoternary ZrO-ZrN-ZrC system.Theses phases have cubic crystalline structure with a o parameter depending on the C, O 2 and N 2 content.These phases have many potential applications in the manufacture of ceramic pieces utilizable as electronic conductors.The Zr (C,O,N) phases can be obtained from ZrO 2 by carbonitriding reactions: that is carbothermal reduction and simultaneous nitriding.In this work a series of experiences of carbonitriding of zirconia under different conditions (temperatures between 1400 and 1600degC, times of 120 min, carbon content between 20 and 40%) in order to obtain suitable powders to be sintered.The XRD analysis shows the Zr(C,O,N) as the main products and β -ZrON as the only secondary product in proportions depending on the obtaining conditions.The variables employed were the C content and the reaction temperature.The Zr(C,O,N) content varies between 40 and 90% and tends to increase with the temperature and the carbon content whereas the β -ZrON phase varies between the 40 and 10 % decreasing its proportion with temperature and the carbon content.The oxidation resistance of these phases was studied by DTA-TG tests in air.Results show complete oxidation reaction at ∼500degC in air.The sintering of these materials was made on disks obtained by pressing of powders of Zr(C,N,O) contents higher than 90%.Sintering was performed in nitrogen atmosphere and temperatures between 1450 and 1620degC.Disks were characterized by pycnometry and Hg volumeter.The densities obtained were between 5 and 6,6g/cm 3 with a tendency to increase with the Zr(C,N,O) phase content, the temperature and the sintering time.Sintered disks were characterized by dilatometry in N 2

  5. Enzymatic lipid oxidation by eosinophils propagates coagulation, hemostasis, and thrombotic disease

    Science.gov (United States)

    Uderhardt, Stefan; Ackermann, Jochen A.; Fillep, Tobias; Hammond, Victoria J.; Willeit, Johann; Stark, Konstantin; Rossaint, Jan; Schubert, Irene; Mielenz, Dirk; Dietel, Barbara; Raaz-Schrauder, Dorette; Ay, Cihan; Thaler, Johannes; Heim, Christian; Collins, Peter W.; Schabbauer, Gernot; Mackman, Nigel; Voehringer, David; Nadler, Jerry L.; Lee, James J.; Massberg, Steffen; Rauh, Manfred; O’Donnell, Valerie B.

    2017-01-01

    Blood coagulation is essential for physiological hemostasis but simultaneously contributes to thrombotic disease. However, molecular and cellular events controlling initiation and propagation of coagulation are still incompletely understood. In this study, we demonstrate an unexpected role of eosinophils during plasmatic coagulation, hemostasis, and thrombosis. Using a large-scale epidemiological approach, we identified eosinophil cationic protein as an independent and predictive risk factor for thrombotic events in humans. Concurrent experiments showed that eosinophils contributed to intravascular thrombosis by exhibiting a strong endogenous thrombin-generation capacity that relied on the enzymatic generation and active provision of a procoagulant phospholipid surface enriched in 12/15-lipoxygenase–derived hydroxyeicosatetraenoic acid–phosphatidylethanolamines. Our findings reveal a previously unrecognized role of eosinophils and enzymatic lipid oxidation as regulatory elements that facilitate both hemostasis and thrombosis in response to vascular injury, thus identifying promising new targets for the treatment of thrombotic disease. PMID:28566277

  6. Milk coagulation properties and methods of detection

    Directory of Open Access Journals (Sweden)

    Simone Beux

    2017-09-01

    Full Text Available ABSTRACT: One of the most crucial steps in cheesemaking is the coagulation process, and knowledge of the parameters involved in the clotting process plays an important technological role in the dairy industry. Milk of different ruminant species vary in terms of their coagulation capacities because they are influenced by the milk composition and mainly by the milk protein genetic variants. The milk coagulation capacity can be measured by means of mechanical and/or optical devices, such as Lactodynamographic Analysis and Near-Infrared and Mid-Infrared Spectroscopy.

  7. Immobilization of Uranium Silicides in Sintered Glass

    International Nuclear Information System (INIS)

    Mateos, P.; Russo, D.O.; Heredia, A.D.; Sanfilippo, M.

    2003-01-01

    High activity nuclear spent fuels vitrification by fusion is a well known technology which has industrial scale in France, England, Japan, EEUU. Borosilicates glasses are used in this process.Sintered glasses are an alternative to the immobilization task in which there is also a wide experience around the world.The available technics are: cold pressing and sintering , hot-pressing and hot isostatic pressing.This work compares Borosilicates and Iron silicates sintered glasses behaviour when different ammounts of nuclear simulated waste is added

  8. Solidification of HLLW into sintered ceramics

    International Nuclear Information System (INIS)

    O-Oka, K.; Ohta, T.; Masuda, S.; Tsunoda, N.

    1979-01-01

    Simulated HLLW from the PNC reprocessing plant at Tokai was solidified into sintered ceramics by normal sintering or hot-pressing with addition of some oxides. Among various ceramic products obtained so far, the most preferable was nepheline-type sintered solids formed with addition of SiO 2 and Al 2 O 3 to the simulated waste calcine. The solid shows advantageous properties in leach rate and mechanical strength, which suggest that the ceramic solids were prepared with additions of ZrO 2 or MnO 2 , and some of them showed good characteristics

  9. Effect of sintering temperature and heating mode on consolidation of ...

    Indian Academy of Sciences (India)

    Microwave sintering was performed in 2.45 GHz multimode microwave furnace at temperatures ranging from 570–630 °C. Microwave sintering at a heating rate of as high as 22°C/min resulted in ∼55% reduction of processing time as compared to conventional sintering. A lower sintered density observed in the case of ...

  10. Sintering of nano crystalline o silicon carbide doping with

    Indian Academy of Sciences (India)

    Sinterable silicon carbide powders were prepared by attrition milling and chemical processing of an acheson type -SiC. Pressureless sintering of these powders was achieved by addition of aluminium nitride together with carbon. Nearly 99% sintered density was obtained. The mechanism of sintering was studied by ...

  11. Arsenic removal in water by means of coagulation-flocculation processes

    International Nuclear Information System (INIS)

    Franco, M. F.; Carro P, M. E.

    2014-01-01

    Arsenic and arsenical compounds are considered as carcinogenic and risky for humans according to epidemiological evidence related with the ingestion of arsenical water during a long period. In many places the only source of drinking water contains arsenic and, therefore, removal strategies have to be investigated. This work shows experimental results of coagulation-flocculation processes implemented to evaluate the efficiency in the removal of arsenic from drinking water. The main objectives include the evaluation of the relevant aspect that controls the removal efficiency. Experimental tests were performed with coagulant concentrations from 5 to 500 mg/L, solid particle concentrations from 0 to 6000 mg/L, and initial arsenic concentrations from 0.5 to 5 mg/L. These variables were simultaneously varied in more than 100 experiments. The efficiency in remediation ranged from 0% to 95%. Removal efficiency near 95% was obtained when using ferric chloride as coagulant, and was close to 80% when using aluminium sulfate as coagulant in arsenate solutions. The remediation efficiency decreased significantly when the ferric chloride concentration was higher than 50 mg/L in relation to the obtained results for aluminum sulfate for different type and concentration of soil particles. The highest removal efficiency were obtained at ph between 3 and 5 in oxidized solutions. Obtained results simulated by means of multiple linear regression analysis (R>0.90) allow determining that the main parameters that control the removal of arsenic from drinking water are coagulant concentration, ph, and solid particles concentration. Conversely, particle mineralogy and coagulant type have less significant effect on the removal by means of coagulation-flocculation mechanisms. Obtained results are relevant for the removal of As in water treatment plants as well as for the development of small scale filters. The samples were studied by scanning electron microscopy and energy dispersive X

  12. Chronic Disseminated Intravascular Coagulation: A Case Report

    Directory of Open Access Journals (Sweden)

    Md Abul Kalam Azad

    2009-11-01

    Full Text Available In health there is a balance between the coagulation and anti-coagulation systems, but in disseminated intravascular coagulation (DIC the coagulation mechanism is activated inappropriately and in a diffuse way. This may lead to thrombosis, but more often haemorrhage occurs when the clotting factors are exhausted. DIC may present as acute, subacute, and rarely chronic form. Here we present a case of chronic DIC following pelvic inflammatory disease (PID as a consequence of repeated menstruation regulation (MR. We treated her with fresh frozen plasma, fresh blood, doxycycline with significant clinical improvement.DOI: 10.3329/bsmmuj.v1i1.3696 BSMMU J 2008; 1(1: 33-34

  13. Quantifying interspecific coagulation efficiency of phytoplankton

    DEFF Research Database (Denmark)

    Hansen, J.L.S.; Kiørboe, Thomas

    1997-01-01

    Non-sticky latex beads and sticky diatoms were used as models to describe mutual coagulation between sticky and non-sticky particles. in mixed suspensions of beads and Thalassiosira nordenskjoeldii, both types of particles coagulated into mixed aggregates at specific rates, from which...... the interspecific coagulation efficiency could be calculated. Stickiness between beads and T. nordenskjoeldii was 50% of that of T. nordenskjoeldii in monospecific suspensions, and this ratio remained constant throughout 12 experiments covering 1 order of magnitude variation in the stickiness level of T....... nordenskjoeldii. Mutual coagulation between Skeletonema costatum and the non-sticky cel:ls of Ditylum brightwellii also proceeded with hall the efficiency of S. costatum alone. The latex beads were suitable to be used as 'standard particles' to quantify the ability of phytoplankton to prime aggregation...

  14. U3O8 microspheres sintering kinetics

    International Nuclear Information System (INIS)

    Godoy, A.L.E.

    1986-01-01

    U 3 O 8 microspheres sintering kinetics was determined using a hot-stage optical microscopy apparatus, able to reach temperature up to 1350 0 C in controlled atmospheres. The sintered material had its microstructure analysed by optical and electron microscopy. The microspheres were characterized initialy utilizing X-ray diffractometry and thermogravimetry. The equation which describes the microspheres shrinkage in function of the time was obtained using finite difference analysis X-ray diffractometry indicated hexagonal structure for the microspheres main starting material, ammonium diuranate thermogravimetric analysis showed reduction of this material to U 3 O 8 at 600 0 C. Ceramography results showed 5 hours sintered microspheres grain sizes G vary with the temperature. Sintered U 3 O 8 micrographs compared with published results for UO 2 , indicate similar homogeneity microstructural characteristics and suggest the processed micorspheres to be potentially useful as nuclear fuels. (Author) [pt

  15. A phenomenological model of milk coagulation

    OpenAIRE

    Osintsev, A.; Gromov, E.; Braginsky, V.

    2013-01-01

    A model of additional stabilization for the milk colloid system by means of the micelle electric charge arising owing to dissociation of micellar calcium caseinate is offered. The model allows comprehending the unique role of calcium in milk clotting and describing some features of coagulation temperature dependence, as well as explaining the nature of rennet, acid, heat-acid and heat-calcium coagulation within uniform concepts.

  16. Effects of nucleotides and nucleosides on coagulation

    DEFF Research Database (Denmark)

    Bune, Laurids; Thaning, Pia; Johansson, Pär I

    2010-01-01

    Nucleotides, including ADP, ATP and uridine triphosphate (UTP), are discharged profusely in the circulation during many pathological conditions including sepsis. Sepsis can cause hypotension and systemic activation of the coagulation and fibrinolytic systems in humans, which may cause disseminated...... intravascular coagulation. We investigated whether nucleotide-induced cardiovascular collapse as provoked by systemic infusion of adenosine, ADP, ATP, UTP and nitric oxide affected the haemostatic system as assessed by whole blood thromboelastography (TEG) analysis. Ten pigs received a randomized infusion...

  17. Removal of silver nanoparticles by coagulation processes

    International Nuclear Information System (INIS)

    Sun, Qian; Li, Yan; Tang, Ting; Yuan, Zhihua; Yu, Chang-Ping

    2013-01-01

    Highlights: • This study investigated the removal of AgNP suspensions by four regular coagulants. • The optimal removal efficiencies for the four coagulants were achieved at pH 7.5. • The removal efficiency of AgNPs was affected by the natural water characteristics. • TEM and XRD showed that AgNPs or silver-containing NPs were adsorbed onto the flocs. -- Abstract: Commercial use of silver nanoparticles (AgNPs) will lead to a potential route for human exposure via potable water. Coagulation followed by sedimentation, as a conventional technique in the drinking water treatment facilities, may become an important barrier to prevent human from AgNP exposures. This study investigated the removal of AgNP suspensions by four regular coagulants. In the aluminum sulfate and ferric chloride coagulation systems, the water parameters slightly affected the AgNP removal. However, in the poly aluminum chloride and polyferric sulfate coagulation systems, the optimal removal efficiencies were achieved at pH 7.5, while higher or lower of pH could reduce the AgNP removal. Besides, the increasing natural organic matter (NOM) would reduce the AgNP removal, while Ca 2+ and suspended solids concentrations would also affect the AgNP removal. In addition, results from the transmission electron microscopy and X-ray diffraction showed AgNPs or silver-containing nanoparticles were adsorbed onto the flocs. Finally, natural water samples were used to validate AgNP removal by coagulation. This study suggests that in the case of release of AgNPs into the source water, the traditional water treatment process, coagulation/sedimentation, can remove AgNPs and minimize the silver ion concentration under the well-optimized conditions

  18. Thermal barrier coating resistant to sintering

    Science.gov (United States)

    Subramanian, Ramesh; Seth, Brij B.

    2004-06-29

    A device (10) is made, having a ceramic thermal barrier coating layer (16) characterized by a microstructure having gaps (18) with a sintering inhibiting material (22) disposed on the columns (20) within the gaps (18). The sintering resistant material (22) is stable over the range of operating temperatures of the device (10), is not soluble with the underlying ceramic layer (16) and is applied by a process that is not an electron beam physical vapor deposition process.

  19. Analysis of Laser Sintering Technology

    Directory of Open Access Journals (Sweden)

    Vladislav Markovič

    2014-02-01

    Full Text Available The new, high-tech development and customization is one ofthe most important factors in promoting the country‘s economicgrowth indicators. The economic downturn in the industryrequires technology and equipment using a minimumof raw materials and providing maximum performance. Thisstatement perfectly describes the innovative, forward-looking,cost-effective laser powder sintering (SLS technology. Here,thanks to the latest engineering achievements, product surfacesare modified and improved, they gain new characteristics. SLSis viable in automobile, engineering, construction, aerospace,aircraft, printing, medical and other areas.In order to create a product which meets the standards andtechnical documentation it is necessary to use and ensure highquality of raw materials, high-end equipment, qualified personnel,the working environment with proper climatic conditions, ergonomics,etc. But all of these, the quality of the product becomesthe decisive indicators meaningless if know how to properly selectthe laser processing operation. Scanning speed, beam power,pulse frequency, protective gases, powder layer thickness – allof them are the physical and mechanical characteristics of thechange in a small range changes the quality of the product of thefuture, the field of application and performance characteristics.

  20. EVALUATION OF INDUSTRIAL DYEING WASTEWATER TREATMENT WITH COAGULANTS AND POLYELECTROLYTE AS A COAGULANT AID

    Directory of Open Access Journals (Sweden)

    G. R. Nabi Bidhendi;A. Torabian;H. Ehsani;N. Razmkhah

    2007-01-01

    Full Text Available Textile industry is the major source of water consumption and wastewater pollution. There are various treatment techniques to remove textile wastewater pollution. Coagulation-flocculation is a widely used process to remove pollution due to suspended particles. In this research, different coagulants like Alum, Lime, FeCl3, FeSO4 and MgCl2 were applied to select the suitable ones with optimum removal efficiency. Settling characteristics of flocs formed in the coagulation process were studied in a laboratory scale settling column unit. Parameters such as color, COD, TSS, turbidity and settled sludge volume have been evaluated. The optimum coagulant dose and pH value were determined by comparing the effectiveness of these coagulants. Results showed other coagulants except lime could eliminate color and COD successfully. In this case, FeSO4 was chosen as an optimum coagulant for color removal because of the lowest required coagulant dose, minimum settled sludge volume and maximum decolorization.

  1. Discrimination symbol applying method for sintered nuclear fuel product

    International Nuclear Information System (INIS)

    Ishizaki, Jin

    1998-01-01

    The present invention provides a symbol applying method for applying discrimination information such as an enrichment degree on the end face of a sintered nuclear product. Namely, discrimination symbols of information of powders are applied by a sintering aid to the end face of a molded member formed by molding nuclear fuel powders under pressure. Then, the molded product is sintered. The sintering aid comprises aluminum oxide, a mixture of aluminum oxide and silicon dioxide, aluminum hydride or aluminum stearate alone or in admixture. As an applying means of the sintering aid, discrimination symbols of information of powders are drawn by an isostearic acid on the end face of the molded product, and the sintering aid is sprayed thereto, or the sintering aid is applied directly, or the sintering aid is suspended in isostearic acid, and the suspension is applied with a brush. As a result, visible discrimination information can be applied to the sintered member easily. (N.H.)

  2. Solid-state sintering of tungsten heavy alloys

    International Nuclear Information System (INIS)

    Gurwell, W.E.

    1994-10-01

    Solid-state sintering is a technologically important step in the fabrication of tungsten heavy alloys. This work addresses practical variables affecting the sinterability: powder particle size, powder mixing, and sintering temperature and time. Compositions containing 1 to 10 micrometer (μM) tungsten (W) powders can be fully densified at temperatures near the matrix solidus. Blending with an intensifier bar provided good dispersion of elemental powders and good as-sintered mechanical properties under adequate sintering conditions. Additional ball milling increases powder bulk density which primarily benefits mold and die filling. Although fine, 1 μm W powder blends have high sinterability, higher as-sintered ductilities are reached in shorter sintering times with coarser, 5 μm W powder blends; 10μm W powder blends promise the highest as-sintered ductilities due to their coarse microstructural W

  3. Coagulation-agglomeration of fractal-like particles: structure and self-preserving size distribution.

    Science.gov (United States)

    Goudeli, Eirini; Eggersdorfer, Maximilian L; Pratsinis, Sotiris E

    2015-02-03

    Agglomeration occurs in environmental and industrial processes, especially at low temperatures where particle sintering or coalescence is rather slow. Here, the growth and structure of particles undergoing agglomeration (coagulation in the absence of coalescence, condensation, or surface growth) are investigated from the free molecular to the continuum regime by discrete element modeling (DEM). Particles coagulating in the free molecular regime follow ballistic trajectories described by an event-driven method, whereas in the near-continuum (gas-slip) and continuum regimes, Langevin dynamics describe their diffusive motion. Agglomerates containing about 10-30 primary particles, on the average, attain their asymptotic fractal dimension, D(f), of 1.91 or 1.78 by ballistic or diffusion-limited cluster-cluster agglomeration, corresponding to coagulation in the free molecular or continuum regimes, respectively. A correlation is proposed for the asymptotic evolution of agglomerate D(f) as a function of the average number of constituent primary particles, n̅(p). Agglomerates exhibit considerably broader self-preserving size distribution (SPSD) by coagulation than spherical particles: the number-based geometric standard deviations of the SPSD agglomerate radius of gyration in the free molecular and continuum regimes are 2.27 and 1.95, respectively, compared to ∼1.45 for spheres. In the transition regime, agglomerates exhibit a quasi-SPSD whose geometric standard deviation passes through a minimum at Knudsen number Kn ≈ 0.2. In contrast, the asymptotic D(f) shifts linearly from 1.91 in the free molecular regime to 1.78 in the continuum regime. Population balance models using the radius of gyration as collision radius underestimate (up to about 80%) the small tail of the SPSD and slightly overpredict the overall agglomerate coagulation rate, as they do not account for cluster interpenetration during coagulation. In the continuum regime, when a recently developed

  4. PROJECT OF COAGULANT DISPENSER IN PULVERIZATION AERATOR WITH WIND DRIVE

    Directory of Open Access Journals (Sweden)

    Ewa Osuch

    2017-09-01

    Full Text Available Lakes are one of most important freshwater ecosystems, playing significant role in functioning of nature and human economy. Swarzędzkie Lake is good example of ecosystem, which in last half-century was exposed to the influence of strong anthropopressure. Direct inflow of sewage with large number of biogens coming to the lake with water of inflows caused distinct disturbance of its functioning. In autumn 2011 restoration begined on Swarzędzkie Lake for reduction of lake trophy and improvement of water quality. For achieving better and quicker effect, simultaneously combination of some methods was applied, among others method of oxygenation of over-bottom water with help of pulverization aerator and method of precise inactivation of phosphorus in water depths. Characterization and analysis of improved coagulant dispenser applying active substance only during work of pulverization aerator is the aim of this thesis. Principle of dispenser work, its structure and location in pulverization aerator were explained. It was stated, that introduction to water a factor initiating process of phosphorus inactivation causes significant reduction of mineral phosphorus in water and size of coagulant dose correlates with intensity of work of pulverization aerator with wind drive.

  5. Hemorrhoidectomy: pedicle ligation vs pedicle coagulation

    International Nuclear Information System (INIS)

    Shaikh, B.S.; Balaoch, I.B.; Sohu, K.M.

    2015-01-01

    Objective: To compare the outcome of pedicle ligation vs pedicle coagulation haemorrhoidectomy. Methodology: This comparative prospective study was carried out at Department of Surgery, Ghulam Muhammad Maher Medcial College Hospital, Sukkur, Pakistan from January 2011 to January 2013 and included 300 patients of hemorrhoids. After routine workup, patients were randomly divided into two equal groups with one group receiving pedicle ligation and other pedicle coagulation for hemorrhoidectomy. Postoperatively they were followed for a period of 8 weeks for complications including pain, urinary retention, bleeding and anal stricture. Pain was recorded up to 10th postoperative day on the basis of visual analogue scale. Results: Mean age was 45 years and male to female ratio was 1.7:1. Mean operative time in pedicle ligation group was 15 min (range 14-20 min) and 17 min (15-25 min) in pedicle coagulation group. In Pedicle ligation group, pain was worst in 35 patients, moderate in 85 and mild in 30 patients; on the other hand in pedicle coagulation group, just 09 patients experienced worst pain. Urinary retention was observed in 44 patients in pedicle ligation group and 19 in pedicle coagulation group. Five patients in pedicle ligation group developed bleeding after their discharge from hospital; 7 patients in pedicle coagulation group reported secondary bleeding. Anal stricture was a rare complication and was found equally common in both the groups. Conclusion: Conventional hemorrhoidectomy with pedicle coagulation is an effective treatment modality for hemorrhoids and is associated with less chance of postoperative anal pain and urinary retention. (author)

  6. Determination of total chlorine and bromine in solid wastes by sintering and inductively coupled plasma-sector field mass spectrometry

    International Nuclear Information System (INIS)

    Osterlund, Helene; Rodushkin, Ilia; Ylinenjaervi, Karin; Baxter, Douglas C.

    2009-01-01

    A sample preparation method based on sintering, followed by analysis by inductively coupled plasma-sector field mass spectrometry (ICP-SFMS) for the simultaneous determination of chloride and bromide in diverse and mixed solid wastes, has been evaluated. Samples and reference materials of known composition were mixed with a sintering agent containing Na 2 CO 3 and ZnO and placed in an oven at 560 deg. C for 1 h. After cooling, the residues were leached with water prior to a cation-exchange assisted clean-up. Alternatively, a simple microwave-assisted digestion using only nitric acid was applied for comparison. Thereafter the samples were prepared for quantitative analysis by ICP-SFMS. The sintering method was evaluated by analysis of certified reference materials (CRMs) and by comparison with US EPA Method 5050 and ion chromatography with good agreement. Median RSDs for the sintering method were determined to 10% for both chlorine and bromine, and median recovery to 96% and 97%, respectively. Limits of detection (LODs) were 200 mg/kg for chlorine and 20 mg/kg for bromine. It was concluded that the sintering method is suitable for chlorine and bromine determination in several matrices like sewage sludge, plastics, and edible waste, as well as for waste mixtures. The sintering method was also applied for determination of other elements present in anionic forms, such as sulfur, arsenic, selenium and iodine

  7. Effects of sintering atmosphere and initial particle size on sintering of gadolinia-doped ceria

    International Nuclear Information System (INIS)

    Batista, Rafael Morgado

    2014-01-01

    The effects of the sintering atmosphere and initial particle size on the sintering of ceria containing 10 mol% gadolinia (GdO 1.5 ) were systematically investigated. The main physical parameter was the specific surface area of the initial powders. Nanometric powders with three different specific surface areas were utilized, 210 m 2 /g, 36,2 m 2 /g e 7,4 m 2 /g. The influence on the densification, and micro structural evolution were evaluated. The starting sintering temperature was verified to decrease with increasing on the specific surface area of raw powders. The densification was accelerated for the materials with smaller particle size. Sintering paths for crystallite growth were obtained. Master sintering curves for gadolinium-doped ceria were constructed for all initial powders. A computational program was developed for this purpose. The results for apparent activation energy showed noticeable dependence with specific surface area. In this work, the apparent activation energy for densification increased with the initial particle size of powders. The evolution of the particle size distributions on non isothermal sintering was investigated by WPPM method. It was verified that the grain growth controlling mechanism on gadolinia doped ceria is the pore drag for initial stage and beginning of intermediate stage. The effects of the sintering atmosphere on the stoichiometry deviation of ceria, densification, microstructure evolution, and electrical conductivity were analyzed. Inert, oxidizing, and reducing atmospheres were utilized on this work. Deviations on ceria stoichiometry were verified on the bulk materials. The deviation verified was dependent of the specific surface area and sintering atmosphere. Higher reduction potential atmospheres increase Ce 3+ bulk concentration after sintering. Accelerated grain growth and lower electrical conductivities were verified when reduction reactions are significantly present on sintering. (author)

  8. Applying "Spark Plasma Sintering" Technology to Enhance the Resistance to Contact Fatigue of Sintered Steel Based on Astaloy CRL

    Science.gov (United States)

    Rodziňák, D.; Čerňan, J.; Puchý, V.

    2017-12-01

    The article deals with the effect of porosity on the contact fatigue of sintered material type Astaloy CrL with 0.3 and 0.4% C. Sets of samples were used with densities beginning from the value of 7000 kg.m-3 to the value of almost 7859 kg.m-3 which represents almost zero porosity (compact material). It has been found out that the increase of compacting pressure applied simultaneously with temperature results in the reduction of porosity from the value of 9.10% to 0.0005% and increase in hardness from 145 to 193 HV10, depending on the carbon content. Logically there is also an increase in the fatigue life by the contact fatigue tests for the value of 50×106 cycles from the value of 900 MPa to 1150 MPa for samples with 0.3% of C and from 900 MPa to 1300 MPa for samples with 0.4% C. These investigations were also carried out in the past, but to achieve the reduction of porosity, different technonologies were used at each level such as double pressing, hot pressing, saturation, hot forging, etc. In this case, the single technology of "spark plasma sintering" making use of compacting at high temperatures is capable to continuously reduce porosity to zero.

  9. Master sintering curve: A practical approach to its construction

    Directory of Open Access Journals (Sweden)

    Pouchly V.

    2010-01-01

    Full Text Available The concept of a Master Sintering Curve (MSC is a strong tool for optimizing the sintering process. However, constructing the MSC from sintering data involves complicated and time-consuming calculations. A practical method for the construction of a MSC is presented in the paper. With the help of a few dilatometric sintering experiments the newly developed software calculates the MSC and finds the optimal activation energy of a given material. The software, which also enables sintering prediction, was verified by sintering tetragonal and cubic zirconia, and alumina of two different particle sizes.

  10. Calcium Hex aluminate reaction sintering by Spark Plasma Sintering; Sinterizacion reactiva de Hexaluminato de Calcio mediante Spark Plasma Sintering

    Energy Technology Data Exchange (ETDEWEB)

    Iglesia, P. G. de la; Garcia-Moreno, O.; Torrecillas, R.; Menendez, J. L.

    2012-11-01

    Calcium hex aluminate (CaAl{sub 1}2O{sub 1}9) is the most alumina-rich intermediate compound of the CaO-Al{sub 2}O{sub 3} system. The formation of this aluminate is produced by the reaction between calcium oxide and alumina with the consequent formation of intermediates compounds with lower alumina content with increasing temperature (CaAl{sub 2}O{sub 4}, CaAl4O{sub 7}). In this study we studied the variation of sintering parameters for obtaining dense and pure calcium hex aluminate by reaction sintering by Spark Plasma Sintering (SPS). A mixing of Al{sub 2}O{sub 3} and CaCO{sub 3} were used as reactive. Final densities close to the theoretical and phase transformation over 93% were achieved by this method. (Author) 22 refs.

  11. Could light meal jeopardize laboratory coagulation tests?

    Science.gov (United States)

    Lima-Oliveira, Gabriel; Salvagno, Gian Luca; Lippi, Giuseppe; Danese, Elisa; Gelati, Matteo; Montagnana, Martina; Picheth, Geraldo; Guidi, Gian Cesare

    2014-01-01

    Presently the necessity of fasting time for coagulation tests is not standardized. Our hypothesis is that this can harm patient safety. This study is aimed at evaluating whether a light meal (i.e. breakfast) can jeopardize laboratory coagulation tests. A blood sample was firstly collected from 17 fasting volunteers (12 h). Immediately after blood collection, the volunteers consumed a light meal. Then samples were collected at 1, 2 and 4 h after the meal. Coagulation tests included: activated partial thromboplastin time (APTT), prothrombin time (PT), fibrinogen (Fbg), antithrombin III (AT), protein C (PC) and protein S (PS). Differences between samples were assessed by Wilcoxon ranked-pairs test. The level of statistical significance was set at P coagulation tests had significant variation after comparison with RCV. A light meal does not influence the laboratory coagulation tests we assessed, but we suggest that the laboratory quality managers standardize the fasting time for all blood tests at 12 hours, to completely metabolize the lipids intake.

  12. Coagulation management in patients undergoing neurosurgical procedures.

    Science.gov (United States)

    Robba, Chiara; Bertuetti, Rita; Rasulo, Frank; Bertuccio, Alessando; Matta, Basil

    2017-10-01

    Management of coagulation in neurosurgical procedures is challenging. In this contest, it is imperative to avoid further intracranial bleeding. Perioperative bleeding can be associated with a number of factors, including anticoagulant drugs and coagulation status but is also linked to the characteristic and the site of the intracranial disorder. The aim of this review will be to focus primarily on the new evidence regarding the management of coagulation in patients undergoing craniotomy for neurosurgical procedures. Antihemostatic and anticoagulant drugs have shown to be associated with perioperative bleeding. On the other hand, an increased risk of venous thromboembolism and hypercoagulative state after elective and emergency neurosurgery, in particular after brain tumor surgery, has been described in several patients. To balance the risk between thrombosis and bleeding, it is important to be familiar with the perioperative changes in coagulation and with the recent management guidelines for anticoagulated patients undergoing neurosurgical procedures, in particular for those taking new direct anticoagulants. We have considered the current clinical trials and literature regarding both safety and efficacy of deep venous thrombosis prophylaxis in the neurosurgical population. These were mainly trials concerning both elective surgical and intensive care patients with a poor grade intracranial bleed or multiple traumas with an associated severe traumatic brain injury (TBI). Coagulation management remains a major issue in patients undergoing neurosurgical procedures. However, in this field of research, literature quality is poor and further studies are necessary to identify the best strategies to minimize risks in this group of patients.

  13. Evaluation of reusing alum sludge for the coagulation of industrial wastewater containing mixed anionic surfactants.

    Science.gov (United States)

    Jangkorn, Siriprapha; Kuhakaew, Sinchai; Theantanoo, Suwapee; Klinla-or, Harit; Sriwiriyarat, Tongchai

    2011-01-01

    A coagulation-flocculation process is typically employed to treat the industrial wastewater generated by the consumer products industry manufacturing detergents, soaps, and others. The expenditure of chemicals including coagulants and chemicals for pH adjustment is costly for treating this wastewater. The objective of this study was to evaluate the feasibility of reusing the aluminum sulfate (alum) sludge as a coagulant or as a coagulation aid so that the fresh alum dosage can be minimized or the removal efficiency can be enhanced. The experiments were conducted in a jar-test apparatus simulating the coagulation-flocculation process for simultaneous removals of organic matters, anionic surfactants, suspended solids, and turbidity. At the optimum initial pH value of 10 and the fresh alum concentration of 400 mg/L, the total suspended solids (TSS), total chemical oxygen demand (TCOD), total anionic surfactants, and turbidity removal efficiencies were 71.5%, 76.4%, 95.4%, and 98.2%, respectively. The addition of alum sludge as a coagulant alone without any fresh alum addition could significantly remove the turbidity, TCOD, and anionic surfactants. The TSS was left in the supernatants after the settling period, but would subsequently be removed by adding the fresh alum. The TSS, TCOD, and turbidity removal efficiencies were also enhanced when both the alum sludge and the fresh alum were employed. The TCOD removal efficiency over 80% has been accomplished, which has never fulfilled by using the fresh alum alone. It is concluded that the alum sludge could be reused for the treatment of industrial wastewater generated by the consumer products industry.

  14. Integrated analysis of oxide nuclear fuel sintering

    International Nuclear Information System (INIS)

    Baranov, V.; Kuzmin, R.; Tenishev, A.; Timoshin, I.; Khlunov, A.; Ivanov, A.; Petrov, I.

    2011-01-01

    Dilatometric and thermal-gravimetric investigations have been carried out for the sintering process of oxide nuclear fuel in gaseous Ar - 8% H 2 atmosphere at temperatures up to 1600 0 C. The pressed compacts were fabricated under real production conditions of the OAO MSZ with application of two different technologies, so called 'dry' and 'wet' technologies. Effects of the grain size growth after the heating to different temperatures were observed. In order to investigate the effects produced by rate of heating on properties of sintered fuel pellets, the heating rates were varied from 1 to 8 0 C per minute. Time of isothermal overexposure at maximal temperature (1600 0 C) was about 8 hours. Real production conditions were imitated. The results showed that the sintering process of the fuel pellets produced by two technologies differs. The samples sintered under different heating rates were studied with application of scanning electronic microscopy analysis for determination of mean grain size. A simulation of heating profile for industrial furnaces was performed to reduce the beam cycles and estimate the effects of variation of the isothermal overexposure temperatures. Based on this data, an optimization of the sintering conditions was performed in operations terms of OAO MSZ. (authors)

  15. New materials through a variety of sintering methods

    Science.gov (United States)

    Jaworska, L.; Cyboroń, J.; Cygan, S.; Laszkiewicz-Łukasik, J.; Podsiadło, M.; Novak, P.; Holovenko, Y.

    2018-03-01

    New sintering techniques make it possible to obtain materials with special properties that are impossible to obtain by conventional sintering techniques. This issue is especially important for ceramic materials for application under extreme conditions. Following the tendency to limit critical materials in manufacturing processes, the use of W, Si, B, Co, Cr should be limited, also. One of the cheapest and widely available materials is aluminum oxide, which shows differences in phase composition, grain size, hardness, strain and fracture toughness of the same type of powder, sintered via various methods. In this paper the alumina was sintered using the conventional free sintering process, microwave sintering, Spark Plasma Sintering (SPS), high pressure-high temperature method (HP-HT) and High Pressure Spark Plasma Sintering (HP SPS). Phase composition analysis, by X-ray diffraction of the alumina materials sintered using various methods, was carried out. For the conventional sintering method, compacts are composed of α-Al2O3 and θ-Al2O3. For compacts sintered using SPS, microwave and HP-HT methods, χ-Al2O3 and γ-Al2O3 phases were additionally present. Mechanical and physical properties of the obtained materials were compared between the methods of sintering. On the basis of images from scanning electron microscope quantitative analysis was performed to determine the degree of grain growth of alumina after sintering.

  16. Monitoring Oral Anticoagulant Therapy: Measuring Coagulant Activity

    DEFF Research Database (Denmark)

    Attermann, Jorn

    daily anticoagulant therapy. The therapy necessitates close monitoring of coagulant activity, since excess doses of anticoagulant medicine may lead to life-threatening bleedings. Traditionally, patients on OAT are required to pay regular visits to a physician, who decides on drug dosage adjustments....... There is general agreement that the quality of the therapy is too low, and often unexpected fluctuations in the coagulant activity are seen. Recently, OAT based on patient self-management has become a realistic alternative by the availability of small portable whole blood coagulometers. An important part...... of the new concept is the training and continuous support and monitoring of the patients, and a center with these purposes has been established at Skejby Sygehus. The main instrument for monitoring the coagulant activity is the prothrombin time (PT). This is the time until clotting can be observed...

  17. Coagulation of charged particles in dust plasma

    International Nuclear Information System (INIS)

    Belov, I.A.; Ivanov, A.S.; Ivanov, D.A.; Pal', A.F.; Starostin, A.N.; Filippov, A.V.; Dem'yanov, A.V.; Petrushevich, Yu.V.

    2000-01-01

    One studied peculiarities of behaviour of small particles in dust plasma resulted on the one hand, from suppression of coagulation due to monopolar charging within the range of particle dimensions under the Debye radius of shielding and, on the other hand, from leveling of this case for particles of large dimensions. On the basis of similarity ratios one determined the range of parameters making linear approximation of particle charge dependence on their dimension true. In terms of the modified classical theory of coagulation in diffusion approximation one studied certain anomalies of behavior of dimension distribution of particles. It is determined that in contrast to the ordinary aerosol in dust plasma as time passes one may reduce dispersion of distribution and average dimensions of particles. For the first time one demonstrates the possibility to realize long-lived quasiliquid state of dust plasma associated with the anomalous behaviour of distribution function of coagulating charged particles according to dimensions [ru

  18. Blood Coagulation and Asthma Exacerbation in Children.

    Science.gov (United States)

    Manuyakorn, Wiparat; Mairiang, Dara; Sirachainan, Nongnuch; Kadegasem, Praguywan; Kamchaisatian, Wasu; Benjaponpitak, Suwat; Chuansumrit, Ampaiwan

    2016-01-01

    Recent studies have demonstrated the activation of coagulation pathways in asthmatic airways. This study aimed to determine systemic blood coagulation during asthma exacerbation compared with the stable state in children. Pediatric patients (aged between 5 and 15 years) suffering from asthma exacerbation were enrolled. von Willebrand factor (vWF), plasminogen activator inhibitor type-1 (PAI-1), protein C, D-dimer, prothrombin fragment 1 + 2 (F1 + 2), thrombin-antithrombin complex (TAT), and C-reactive protein (CRP) levels were measured during asthma exacerbation and stable state. A total of 22 patients were enrolled. The median vWF, PAI-1, and CRP during asthma exacerbation were significantly higher than those of the stable state: 147.5% (interquartile range, IQR: 111.05-196.57) versus 94% (IQR: 69.72-109.62, p coagulation in asthma exacerbation. © 2016 S. Karger AG, Basel.

  19. Sintered cobalt-rare earth intermetallic product

    International Nuclear Information System (INIS)

    Benz, M.G.

    1975-01-01

    This patent describes a sintered product having substantially stable permanent magnet properties in air at room temperature. It comprises compacted particulate cobalt--rare earth alloy consisting essentially of a Co 5 R intermetallic phase and a CoR intermetallic phase which is richer in rare earth metal content than the Co 5 R phase, where R is a rare earth metal. The Co 5 R intermetallic phase is present in an amount of at least 65 percent by weight of the sintered product and the CoR intermetallic phase which is richer in rare earth metal content than the Co 5 R phase is present in a positive amount having a value ranging up to about 35 percent by weight of the product. The sintered product has a density of at least 87 percent and has pores which are substantially noninterconnecting and wherein the component grains have an average size less than 30 microns

  20. Method of manufacturing sintered nuclear fuel

    International Nuclear Information System (INIS)

    Watarumi, Kazutoshi.

    1984-01-01

    Purpose: To obtain composite pellets with an improved strength. Method: A core mainly composed of fuel materials is previously prepared, embedded into the central portion of a pellet, silted therearound with cladding material, and then pressmolded and sintered. For instance, a rugby-ball like core body with the maximum outer diameter of 6 mm and the height of 6 mm is made by compressive molding with uranium dioxide powder, then coating material comprising the same powder incorporated with 0.1 % by weight of SiC fibers is filled around the core body, which is molded into a composite pellet by means of pressing and then sintered at 1600 0 C, to obtain a sintered pellet of 93.5 % theoretical density. As the result of the compression test for the pellet, it showed a strength greater by 15 % than that of the similar mono-layer pellet. (Kamimura, M.)

  1. Sintering of nickel steam reforming catalysts

    DEFF Research Database (Denmark)

    Sehested, Jens; Larsen, Niels Wessel; Falsig, Hanne

    2014-01-01

    The lifetimes of heterogeneous catalysts in many widely used industrial processes are determined by the loss of active surface area. In this context, the underlying physical sintering mechanism and quantitative information about the rate of sintering at industrial conditions are relevant....... In this paper, particle migration and coalescence in nickel steam reforming catalysts is studied. Density functional theory calculations indicate that Ni-OH dominate nickel transport at nickel surfaces in the presence of steam and hydrogen as Ni-OH has the lowest combined energies of formation and diffusion...... compared to other potential nickel transport species. The relation between experimental catalyst sintering data and the effective mass diffusion constant for Ni-OH is established by numerical modelling of the particle migration and coalescence process. Using this relation, the effective mass diffusion...

  2. Design of sintering-stable heterogeneous catalysts

    DEFF Research Database (Denmark)

    Gallas-Hulin, Agata

    the crystalline framework of a zeolite creates a steric hindrance against agglomeration into larger clusters. In the present study, experimental protocols for encapsulation of metal nanoparticles inside zeolites were developed. Two different methodologies were proposed to encapsulate gold, palladium and platinum......One of the major issues in the use of metal nanoparticles in heterogeneous catalysis is sintering. Sintering occurs at elevated temperatures because of increased mobility of nanoparticles, leading to their agglomeration and, as a consequence, to the deactivation of the catalyst. It is an emerging...... problem especially for the noble metals-based catalysis. These metals being expensive and scarce, it is worth developing catalyst systems which preserve their activity over time. Encapsulation of nanoparticles inside zeolites is one of the ways to prevent sintering. Entrapment of nanoparticles inside...

  3. The investigation of coagulation activity of natural coagulants extracted from different strains of common bean

    Directory of Open Access Journals (Sweden)

    Šćiban Marina B.

    2010-01-01

    Full Text Available Coagulation and flocculation by adding chemicals are the methods that are usually used for removal of water turbidity. This study is concerned with the coagulation activity of extracts of various strains of bean. The aim was to ascertain if bean varieties influence coagulation activity. Active components were extracted from 1 g of ground sample with 100 ml distilled water. Contents of dry matter and nitrogen were specified in the solid samples, and the content of soluble nitrogen was determined in the extracts. These data were used to calculate the efficiency of extraction of nitrogen-containing compounds. The coagulation activity was assessed by jar test using synthetic turbid water, of the initial pH 9 and turbidity 35 NTU. The jar test was carried out by adding different amounts of extracts to model water, and stirring the content. After sedimentation for 1 h, residual turbidity was determined by turbidimeter and coagulation activity was calculated. The increment of organic matter concentration after the coagulation was also determined. These experiments confirmed that extracts of all investigated strains of bean could be used successfully as natural coagulants.

  4. Coagulation characteristics of titanium (Ti) salt coagulant compared with aluminum (Al) and iron (Fe) salts.

    Science.gov (United States)

    Zhao, Y X; Gao, B Y; Shon, H K; Cao, B C; Kim, J-H

    2011-01-30

    In this study, the performance of titanium tetrachloride (TiCl(4)) coagulation and flocculation is compared with commonly used coagulants such as aluminum sulfate (Al(2)(SO(4))(3)), polyaluminum chloride (PACl), iron chloride (FeCl(3)), and polyferric sulfate (PFS) in terms of water quality parameters and floc properties. TiCl(4) flocculation achieved higher removal of UV(254) (98%), dissolved organic carbon (DOC) (84%) and turbidity (93%) than other conventional coagulants. Charge neutralization and physical entrapment of colloids within coagulant precipitates and adsorption, seemed to play a significant role during TiCl(4) flocculation, while the main mechanism for conventional coagulants was bridge-aggregation and adsorption. The aggregated flocs after TiCl(4) flocculation showed the fastest growth rate compared to the other coagulants, with the largest floc size (801 μm) occurring within 8 min. The floc strength factor of PACl, Al(2)(SO(4))(3), PFS, FeCl(3) and TiCl(4) was 34, 30, 29, 26 and 29, respectively, while the floc recovery factor of the TiCl(4) coagulant was the lowest. Based on the results of the above study, it is concluded that the TiCl(4) flocculation can reduce the hydraulic retention time of slow and rapid mixing, however, careful handling of sludge is required due to the low recoverability of the aggregated floc. Copyright © 2010 Elsevier B.V. All rights reserved.

  5. Fabrication of 200 mm Diameter Sintering Body of Skutterudite Thermoelectric Material by Spark Plasma Sintering

    Science.gov (United States)

    Tomida, T.; Sumiyoshi, A.; Nie, G.; Ochi, T.; Suzuki, S.; Kikuchi, M.; Mukaiyama, K.; Guo, J. Q.

    2017-05-01

    Filled skutterudite is a promising material for thermoelectric power generation because its ZT value is relatively high. However, mass production of high-performance thermoelectric materials remains a challenge. This study focused on the sintering process of thermoelectric materials. Large-diameter n-type (Yb or La, Ca, Al, Ga, In)0.8(Co, Fe)4Sb12 skutterudite sintering bodies with a small thickness were successfully produced by the spark plasma sintering (SPS) method. When direct current flows through the thermoelectric sintering body during the SPS pulse, the Peltier effect causes a temperature difference within the sintering body. To eliminate the Peltier effect, an electrical insulating material was inserted between the punch (electrode) and the sintering body. In this way, an n-type La-filled skutterudite sample with a diameter of 200 mm, thickness of 21 mm, and weight of 5 kg was successfully produced. The thermoelectric properties and microstructures of the sample were almost the same throughout the whole sintering body, and the dimensionless figure of merit reached 1.0 at 773 K.

  6. PRODUCTION OF WELDMENTS FROM SINTERED TITANIUM ALLOYS

    Directory of Open Access Journals (Sweden)

    A. YE. Kapustyan

    2014-04-01

    Full Text Available Purpose. Limited application of details from powder titanium alloys is connected with the difficulties in obtaining of long-length blanks, details of complex shape and large size. We can solve these problems by applying the welding production technology. For this it is necessary to conduct a research of the structure and mechanical properties of welded joints of sintered titanium alloys produced by flash welding. Methodology. Titanium industrial powders, type PT5-1 were used as original substance. Forming of blanks, whose chemical composition corresponded to BT1-0 alloy, was carried out using the powder metallurgy method. Compounds were obtained by flash welding without preheating. Microstructural investigations and mechanical tests were carried out. To compare the results investigations of BT1-0 cast alloy were conducted. Findings. Samples of welded joints of sintered titanium blanks from VT1-0 alloy using the flash butt welding method were obtained. During welding the microstructure of basic metal consisting of grains of an a-phase, with sizes 40...70 mkm, is transformed for the seam weld and HAZ into the lamellar structure of an a-phase. The remaining pores in seam weld were practically absent; in the HAZ their size was up to 2 mkm, with 30 mkm in the basic metal. Attainable level of mechanical properties of the welded joint in sintered titanium alloys is comparable to the basic metal. Originality. Structure qualitative changes and attainable property complex of compounds of sintered titanium alloys, formed as a result of flash butt welding were found out. Practical value. The principal possibility of high-quality compounds obtaining of sintered titanium alloys by flash welding is shown. This gives a basis for wider application of sintered titanium alloys due to long-length blanks production that are correspond to deformable strand semi finished product.

  7. Phase characterisation in spark plasma sintered TiPt alloy

    CSIR Research Space (South Africa)

    Chikosha, S

    2011-12-01

    Full Text Available The conclusions drawn from this presentation are that Spark Plasma Sintering (SPS) of equiatomic BE TiPt powder produces fully sintered specimens, with incomplete homogenisation. There is a need for improved furnace atmosphere control so...

  8. Process for microwave sintering boron carbide

    Science.gov (United States)

    Holcombe, C.E.; Morrow, M.S.

    1993-10-12

    A method of microwave sintering boron carbide comprises leaching boron carbide powder with an aqueous solution of nitric acid to form a leached boron carbide powder. The leached boron carbide powder is coated with a glassy carbon precursor to form a coated boron carbide powder. The coated boron carbide powder is consolidated in an enclosure of boron nitride particles coated with a layer of glassy carbon within a container for microwave heating to form an enclosed coated boron carbide powder. The enclosed coated boron carbide powder is sintered within the container for microwave heating with microwave energy.

  9. Fusibility and sintering characteristics of ash

    International Nuclear Information System (INIS)

    Ots, A. A.

    2012-01-01

    The temperature characteristics of ash fusibility are studied for a wide range of bituminous and brown coals, lignites, and shales with ratios R B/A of their alkaline and acid components between 0.03 and 4. Acritical value of R B/A is found at which the fusion temperatures are minimal. The sintering properties of the ashes are determined by measuring the force required to fracture a cylindrical sample. It is found that the strength of the samples increases sharply at certain temperatures. The alkali metal content of the ashes has a strong effect on their sintering characteristics.

  10. Effect of rivaroxaban on blood coagulation using the viscoelastic coagulation test ROTEM™.

    Science.gov (United States)

    Casutt, M; Konrad, C; Schuepfer, G

    2012-11-01

    This study investigated the influence of the oral direct inhibitor of factor Xa rivaroxaban on blood coagulation measured by rotation thrombelastometry ROTEM™. Blood was obtained from 11 healthy male volunteers before and 2.5 h after oral administration of 10 mg rivaroxaban. In addition to standard coagulation tests clot formation was measured by ROTEM™ analyzing extrinsic (Extem) and intrinsic thrombelastometry (Intem). Significant differences to the baseline values were found in the Extem clotting time (Extem-CT, 58 ± 9 s and 87 ± 17 s, p coagulation by rivaroxaban.

  11. THE RATIONALIZATION OF THE PARAMETERS OF MILK PROTEINS’ THERMO ACID COAGULATION BY BERRY COAGULANTS

    Directory of Open Access Journals (Sweden)

    Olena GREK

    2017-03-01

    Full Text Available This paper presents the results related to the influence of berry coagulant amount, its proactive acidity and duration of thermo acid coagulation on the process of milk proteins’ sedimentation. In the present work, the regression equations and response surface analysis were used to design and optimize an industrial bioprocess. Increase in the berry coagulant amount to 11 % and reduction of active acidity to 2.4 units were determined. pH up to 3 minutes is characterized by the highest processes of destabilization. Moreover, it improves the organoleptic properties and has the biggest impact on the yield of protein-berry clot (to 25 % and active acidity.

  12. Blood is thicker than water: coagulation challenges in the ...

    African Journals Online (AJOL)

    This manuscript serves to highlight some novel approaches to perioperative coagulation abnormalities and to address unanswered questions. Keywords: coagulation; point-of-care monitor; prothrombin complex concentrate; pharmacological procoagulants ...

  13. Assessing blood coagulation status with laser speckle rheology

    Science.gov (United States)

    Tripathi, Markandey M.; Hajjarian, Zeinab; Van Cott, Elizabeth M.; Nadkarni, Seemantini K.

    2014-01-01

    We have developed and investigated a novel optical approach, Laser Speckle Rheology (LSR), to evaluate a patient’s coagulation status by measuring the viscoelastic properties of blood during coagulation. In LSR, a blood sample is illuminated with laser light and temporal speckle intensity fluctuations are measured using a high-speed CMOS camera. During blood coagulation, changes in the viscoelastic properties of the clot restrict Brownian displacements of light scattering centers within the sample, altering the rate of speckle intensity fluctuations. As a result, blood coagulation status can be measured by relating the time scale of speckle intensity fluctuations with clinically relevant coagulation metrics including clotting time and fibrinogen content. Our results report a close correlation between coagulation metrics measured using LSR and conventional coagulation results of activated partial thromboplastin time, prothrombin time and functional fibrinogen levels, creating the unique opportunity to evaluate a patient’s coagulation status in real-time at the point of care. PMID:24688816

  14. Mechanical characterization and durability of sintered porous transport layers for polymer electrolyte membrane electrolysis

    Science.gov (United States)

    Borgardt, Elena; Panchenko, Olha; Hackemüller, Franz Josef; Giffin, Jürgen; Bram, Martin; Müller, Martin; Lehnert, Werner; Stolten, Detlef

    2018-01-01

    Differential pressure electrolysis offers the potential for more efficient hydrogen compression. Due to the differential pressures acting within the electrolytic cell, the porous transport layer (PTL) is subjected to high stress. For safety reasons, the PTL's mechanical stability must be ensured. However, the requirements for high porosity and low thickness stand in contrast to that for mechanical stability. Porous transport layers for polymer electrolyte membrane (PEM) electrolysis are typically prepared by means of the thermal sintering of titanium powder. Thus far, the factors that influence the mechanical strength of the sintered bodies and how all requirements can be simultaneously fulfilled have not been investigated. Here, the static and dynamic mechanical properties of thin sintered titanium sheets are investigated ex-situ via tensile tests and periodic loading in a test cell, respectively. In order for a sintered PTL with a thickness of 500 μm and porosities above 25% to be able to withstand 50 bar differential pressure in the cell, the maximum flow field width should be limited to 3 mm. Thus, a method was developed to test the suitability of PTL materials for use in electrolysis for various differential pressures and flow field widths.

  15. Disk shaped radiation sources fabricated by compression and formation of sinter powder

    International Nuclear Information System (INIS)

    Kawano, Takao

    2008-01-01

    Sinters are deposits found at the bottom of hot springs, some of which contain naturally occurring radioisotopes of the uranium and thorium series. A disk-shaped radiation source was developed by compressing sinter powder. Ten disk-shaped radiation sources were fabricated by this method and their weight, thickness, mass density, and radioactivity were determined. The results indicated that special skills or techniques are not required for production of a radiation source with this method, and the production method is robust. Thus, the method is suitable for the simultaneous fabrication of multiple uniform radiation sources. To evaluate the ability of this fabrication method to produce sinter radiation sources applicable to courses involving radiation protection or similar investigations, the dependence of the radiation count rate on distance, shielding thickness, and shielding materials was examined using a conventional GM survey meter. The results showed that the sinter radiation source is suitable to comprehend characteristics of radiation and principle of radiation protection related to distance and shielding. (author)

  16. Sintering of dioxide pellets in an oxidizing atmosphere (CO2)

    International Nuclear Information System (INIS)

    Santos, G.R.T.

    1992-01-01

    This work consists in the study of the sintering process of U O 2 pellets in an oxidizing atmosphere. Sintering tests were performed in an CO 2 atmosphere and the influence of temperature and time on the pellets density and microstructure were verified. The results obtained were compared to those from the conventional sintering process and its efficiency was confirmed. (author)

  17. Effect of increasing lanthanum substitution and the sintering ...

    Indian Academy of Sciences (India)

    Administrator

    Young's modulus of the microwave sintered samples (8.8–12.5 and 160–180 GPa) are higher than that for conventional sintered (8–10 and 135–155 GPa) samples. Keywords. Microwave sintering; La-substituted SBTi ceramics; mechanical properties. 1. Introduction. In recent years, bismuth layer-structured ferroelectrics.

  18. Coagulation activity in liver disease | Reza | Internet Journal of ...

    African Journals Online (AJOL)

    Patients with advanced hepatic failure may present with the entire spectrum of coagulation factor deficiencies. This study was designed to determine laboratory abnormalities in coagulation in chronic liver disease and the association of these abnormalities with the extent of chronic hepatitis and cirrhosis. Coagulation ...

  19. Performance of Solanum incunum Linnaeus as natural coagulant ...

    African Journals Online (AJOL)

    The paper reports the performance of Solanum incunum Linnaeus as coagulant and disinfectant for water purification. The coagulation-flocculation experiment was carried out using a Phipps and Bird PB-700™ Jar Tester. Results show that coagulation depends on Fe(II) content and disinfectant on bioactive natural product ...

  20. Effects of sintering temperature on the mechanical properties of sintered NdFeB permanent magnets prepared by spark plasma sintering

    International Nuclear Information System (INIS)

    Wang, G.P.; Liu, W.Q.; Huang, Y.L.; Ma, S.C.; Zhong, Z.C.

    2014-01-01

    Sintered NdFeB-based permanent magnets were fabricated by spark plasma sintering (SPS) and a conventional method to investigate the mechanical and magnetic properties. The experimental results showed that sintered NdFeB magnet prepared by the spark plasma sintering (SPS NdFeB) possesses a better mechanical properties compared to the conventionally sintered one, of which the maximum value of bending strength and Vickers hardness was 402.3 MPa and 778.1 MPa, respectively. The effects of sintering temperature on bending strength and Vickers hardness were investigated. It was shown that the bending strength firstly increases to the maximum value and then decreases with the increase of sintering temperature in a certain range. The investigations of microstructures and mechanical properties indicated that the unique sintering mechanism in the SPS process is responsible for the improvement of mechanical properties of SPS NdFeB. Furthermore, the relations between the mechanical properties and relevant microstructure have been analyzed based on the experimental fact. - Highlights: • Studied the sintering temperature effect on strengthening mechanism of NdFeB magnet firstly. • It showed that sintering temperature may effectively affect the mechanical properties. • The maximum bending strength and Vickers hardness was 402.3 MPa and 778.1 MPa, respectively

  1. Effects of sintering temperature on the mechanical properties of sintered NdFeB permanent magnets prepared by spark plasma sintering

    Energy Technology Data Exchange (ETDEWEB)

    Wang, G.P., E-mail: wgp@jxnu.edu.cn [College of Physics and Communication Electronics, Jiangxi Normal University, Nanchang 330022 (China); Liu, W.Q. [Key Laboratory of Advanced Functional Materials Science and Engineering, Ministry of Education, Beijing University of Technology, Beijing 100022 (China); Huang, Y.L.; Ma, S.C.; Zhong, Z.C. [School of Materials Science and Engineering, Nanchang Hangkong University, Nanchang 330063 (China)

    2014-01-15

    Sintered NdFeB-based permanent magnets were fabricated by spark plasma sintering (SPS) and a conventional method to investigate the mechanical and magnetic properties. The experimental results showed that sintered NdFeB magnet prepared by the spark plasma sintering (SPS NdFeB) possesses a better mechanical properties compared to the conventionally sintered one, of which the maximum value of bending strength and Vickers hardness was 402.3 MPa and 778.1 MPa, respectively. The effects of sintering temperature on bending strength and Vickers hardness were investigated. It was shown that the bending strength firstly increases to the maximum value and then decreases with the increase of sintering temperature in a certain range. The investigations of microstructures and mechanical properties indicated that the unique sintering mechanism in the SPS process is responsible for the improvement of mechanical properties of SPS NdFeB. Furthermore, the relations between the mechanical properties and relevant microstructure have been analyzed based on the experimental fact. - Highlights: • Studied the sintering temperature effect on strengthening mechanism of NdFeB magnet firstly. • It showed that sintering temperature may effectively affect the mechanical properties. • The maximum bending strength and Vickers hardness was 402.3 MPa and 778.1 MPa, respectively.

  2. Blood coagulation factor VIII: An overview

    Indian Academy of Sciences (India)

    Factor VIII (FVIII) functions as a co-factor in the blood coagulation cascade for the proteolytic activation of factor X by factor IXa. Deficiency of FVIII causes hemophilia A, the most commonly inherited bleeding disorder. This review highlights current knowledge on selected aspects of FVIII in which both the scientist and the ...

  3. Coagulants modulate the hypocholesterolemic effect of tofu ...

    African Journals Online (AJOL)

    hope&shola

    2006-02-02

    Feb 2, 2006 ... (P<0.05) total phenol content than tofu produced using other coagulants (8.0 – 9.0 g/kg). Furthermore, ... of tofu with high hypocholesterolemic effect base on the low serum cholesterol, LDL and high HDL. Key words: .... were fed the commercial diet (16.0% proteins), while animals in group 2 were fed ...

  4. Coagulation-flocculation studies of wastewaters

    NARCIS (Netherlands)

    Leentvaar, J.

    1982-01-01

    Although coagulation-flocculation processes have been practiced world-wide for almost a century in water treatment, several problems both in the theoretical and in the applied field have not been resolved yet. Especially interpretation of practical results with respect to governing

  5. Coagulation efficiency of Dicerocaryum eriocarpum (DE) plant ...

    African Journals Online (AJOL)

    Widespread poor land use practices contribute to high turbidity in river water, making turbidity management or removal critical, particularly before the water is used for drinking or subjected to chemical treatment. In this study, mucilage from DE was extracted with deionized water and different chloride solutions. A coagulation ...

  6. Coagulation in Treatment of Swine Slaughterhouse Wastewater

    Directory of Open Access Journals (Sweden)

    Ha Bui Manh

    2017-03-01

    Full Text Available In this study, wastewater taken from the Nam Phong swine slaughterhouse, Ho Chi Minh City, was used to evaluate the treatment efficiency of common coagulants, including Alum (Aluminum Sulfate - Al2(SO43.18H2O, Poly-Aluminum Chloride (PAC, and Ferrous Sulfate (FeSO4.7H2O, using a jar-test system. The experiments were conducted using the one-factor-at-a-time method to examine three variables which are pH, stirring speed, and coagulant dosage. The results showed that both Alum and PAC perform over 90% removal of colour, turbidity, COD, and total phosphorus (TP from slaughterhouse wastewater at pH 7 with a stirring speed of 75 revolutions per minute (RPM and average coagulant dosages of 450 mg/L for Alum and 550 mg/L for PAC. Meanwhile, under the appropriate conditions of pH equal to 10 and 75 RPM with a chemical dosage of 350 mg/L, COD and TP removal efficiencies by Ferrous Sulfate exceed 87%, but those of turbidity and colour only reach 25%. This finding could be a promising coagulation method as a pre-treatment for the swine slaughterhouse wastewater.

  7. Establishing reference intervals in the coagulation laboratory.

    Science.gov (United States)

    Castellone, D D

    2017-05-01

    Obtaining a reference interval (RI) is a challenge for any laboratory and becomes more complicated in the coagulation laboratory due to testing on samples with limited stability on reagents that are poorly standardized. Reference intervals are required to be able to evaluate results in relation to a patients' hemostatic disorder. This becomes one of the most important tasks conducted in the coagulation laboratory. However, many laboratories lack the time, finances and in many cases the expertise to conduct this study. Many RI are obtained from package inserts, or from publications written by experts in lieu of laboratories conducting their own studies. An overview of validating reference intervals and options for verifying or transference of reference intervals is discussed. Based on the confidence interval and the acceptability of risk laboratories are willing to accept, coagulation laboratories have options to conduct robust studies for their RI. Data mining or global reference studies may help to provide data for age specific ranges. Pre-analytical variables and selection of healthy subjects have the largest impact on coagulation testing outcomes and need to be well controlled during the establishment of reference intervals. Laboratories have options in lieu of conducting a full validation on how to verify RI based on smaller RI studies or transference of RI after determining compatibility of the original RI study. © 2017 John Wiley & Sons Ltd.

  8. Comparison of electrocoagulation and chemical coagulation ...

    African Journals Online (AJOL)

    In this work, electrocoagulation and chemical coagulation were applied to the exit effluent of a textile factory located at Douala (Cameroon).The investigations were focused on the operational (pH, conductivity) and pollution parameters (COD, total phosphorus, turbidity). The electrolytic treatment was carried out with 0.4 A ...

  9. Roles for vitamin K beyond coagulation

    Science.gov (United States)

    Recent interest in vitamin K has been motivated by evidence of physiological roles beyond that of coagulation. Vitamin K and vitamin K-dependent proteins may be involved in regulation of calcification, energy metabolism, and inflammation. However, the evidence for many of these proposed roles in the...

  10. Coagulation disorders in dogs with hepatic disease

    NARCIS (Netherlands)

    Prins, M.|info:eu-repo/dai/nl/304836176; Schellens, C.J.M.M.; van Leeuwen, M; Rothuizen, J.|info:eu-repo/dai/nl/071276033; Teske, E.|info:eu-repo/dai/nl/114300240

    2010-01-01

    The Veterinary Journal Volume 185, Issue 2, August 2010, Pages 163-168 -------------------------------------------------------------------------------- doi:10.1016/j.tvjl.2009.05.009 | How to Cite or Link Using DOI Copyright © 2009 Elsevier Ltd All rights reserved. Permissions & Reprints Coagulation

  11. Mechanical characteristics of microwave sintered silicon carbide

    Indian Academy of Sciences (India)

    Unknown

    tions ranging from kiln furniture to membrane material. Keywords. Microwave sintering; biaxial flexure; silicon carbide. 1. Introduction. Silicon carbide (SiC) ceramics is a very well known candidate material for a structural application. However, due to (i) poor densification due to highly directional bonding, (ii) susceptibility of ...

  12. Sintering behavior of LZSA glass-ceramics

    Directory of Open Access Journals (Sweden)

    Oscar Rubem Klegues Montedo

    2009-06-01

    Full Text Available The LZSA glass-ceramic system (Li2O-ZrO2-SiO2-Al2O 3 shows interesting properties, such as good chemical resistance, low thermal expansion, high abrasion resistance, and a low dielectric constant. However, in order to obtain a high performance material for specific applications, the sintering behavior must be better understood so that the porosity may be reduced and other properties improved. In this context, a sintering investigation for a specific LZSA glass-ceramic system composition was carried out. A 18.8Li2O-8.3ZrO2-64.2SiO2-8.7Al 2O3 glass was prepared by melting the solids, quenching the melt in water, and grinding the resulting solid in order to obtain a powder (3.68 μm average particle diameter. Subsequently, the glass powder was characterized (chemical analysis and determination of thermal properties and the sintering behavior was investigated using optical non-contact dilatometry measurements. The results showed that the crystallization process strongly reduced the sintering in the temperature interval from 785 to 940 °C, and a maximum thermal shrinkage of 15.4% was obtained with operating conditions of 1020 °C and 180 minutes.

  13. Low temperature sintering of hyperstoichiometric uranium dioxide

    International Nuclear Information System (INIS)

    Chevrel, H.

    1991-12-01

    In the lattice of uranium dioxide with hyperstoichiometric oxygen content (UO 2+x ), each additional oxygen atoms is introduced by shifting two anions from normal sites to interstitial ones, thereby creating two oxygen vacancies. The point defects then combine to form complex defects comprising several interstitials and vacancies. The group of anions (3x) in the interstitial position participate in equilibria promoting the creation of uranium vacancies thereby considerably increasing uranium self-diffusion. However, uranium grain boundaries diffusion governs densification during the first two stages of sintering of uranium dioxide with hyperstoichiometric oxygen content, i.e., up to 93% of the theoretical density. Surface diffusion and evaporation-condensation, which are considerably accentuated by the hyperstoichiometric deviation, play an active role during sintering by promoting crystalline growth during the second and third stages of sintering. U 8 O 8 can be added to adjust the stoichiometry and to form a finely porous structure and thus increase the pore area subjected to surface phenomena. The composition with an O/U ratio equal to 2.25 is found to densify the best, despite a linear growth in sintering activation energy with hyperstoichiometric oxygen content, increasing from 300 kj.mol -1 for UO 2.10 to 440 kJ.mol -1 for UO 2.25 . Seeds can be introduced to obtain original microstructures, for example the presence of large grains in small-grain matrix

  14. Study of ceramics sintering under high pressures

    International Nuclear Information System (INIS)

    Kunrath Neto, A.O.

    1990-01-01

    A systematic study was made on high pressure sintering of ceramics in order to obtain materials with controlled microstructure, which are not accessible by conventional methods. Some aspects with particular interest were: to achieve very low porosity, with fine grains; to produce dispersed metastable and denser phases which can act as toughening agents; the study of new possibilities for toughening enhancement. (author)

  15. Deformation behavior of sintered nanocrystalline silver layers

    International Nuclear Information System (INIS)

    Zabihzadeh, S.; Van Petegem, S.; Duarte, L.I.; Mokso, R.; Cervellino, A.; Van Swygenhoven, H.

    2015-01-01

    The microstructure of porous silver layers produced under different low temperature pressure-assisted sintering conditions is characterized and linked with the mechanical behavior studied in situ during X-ray diffraction. Peak profile analysis reveals important strain recovery and hardening mechanism during cyclic deformation. The competition between both mechanisms is discussed in terms of porosity and grain size

  16. Air-sintering mechanisms of chromites

    Energy Technology Data Exchange (ETDEWEB)

    Chick, L.A.; Bates, J.L.; Maupin, G.D.

    1991-07-01

    The sintering behaviors of La{sub 1-x}Sr{sub x}CrO{sub 3} and Y{sub 1-x}Ca{sub x}CrO{sub 3} in air at 1550{degrees}C are described as functions of alkaline earth concentration and chromium enrichment or depletion. Vapor-, liquid-, and solid-phase mass transport mechanisms appear to be operative in both systems. Liquid-phase sintering appears dominant an Y{sub 1-x}Ca{sub x}CrO{sub 3} with x = 0.15 to 0.40, especially with Cr enrichment. Either vapor- or solid-phase transport may dominate in the La{sub 1-x}Sr{sub x}CrO{sub 3} system. Slight depletion or enrichment of Cr in both systems has dramatic effects on air-sintered density and microstructure, probably due to modulation of vapor-phase transport and liquid-phase formation. Substantial Cr depletion enhances sintering. 10 refs., 9 figs.

  17. Mechanical characterization of microwave sintered zinc oxide

    Indian Academy of Sciences (India)

    Unknown

    Keywords. Zinc oxide; microwave sintering; microhardness. 1. Introduction. The application of microwave energy for the processing of ceramics has become an attractive area of research and innovation recently. The major advantages of the micro- wave processing of ceramic materials are accelerated densification rate as a ...

  18. Laser Sintering Technology and Balling Phenomenon.

    Science.gov (United States)

    Oyar, Perihan

    2018-02-01

    The aim of this review was to evaluate the balling phenomenon which occurs typically in Selective Laser Sintering (SLS). The balling phenomenon is a typical SLS defect, and observed in laser sintered powder, significantly reduces the quality of SLS, and hinders the further development of SLS Technology. Electronic database searches were performed using Google Scholar. The keywords "laser sintering, selective laser sintering, direct metal laser melting, and balling phenomenon" were searched in title/abstract of publications, limited to December 31, 2016. The inclusion criteria were SLS, balling phenomenon, some alloys (such as Cr-Co, iron, stainless steel, and Cu-based alloys) mechanical properties, microstructure and bond strength between metal-ceramic crown, laboratory studies, full text, and in English language. A total of 100 articles were found the initial search and yielded a total of 50 studies, 30 of which did not fulfill the inclusion criteria and were therefore excluded. In addition, 20 studies were found by screening the reference list of all included publications. Finally, 40 studies were selected for this review. The method in question is regulated by powder material characteristics and the conditions of laser processing. The procedure of formation, affecting factors, and the mechanism of the balling effect are very complex.

  19. Sintering of silicon nitride ceramics with magnesium silicon nitride and yttrium oxide as sintering aids

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, J; Xu, J Y [Shanghai Institute of Technology, Shanghai 200235 (China); Peng, G H [Guangxi Normal University, Guilin 541004, Guangxi (China); Zhuang, H R; Li, W L; Xu, S Y [Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 200050 (China); Mao, Y J, E-mail: guojianjiang@sit.edu.cn [Shanghai University, Shanghai 200444 (China)

    2011-10-29

    Silicon nitride (Si{sub 3}N{sub 4}) ceramics had been produced through pressureless sintering and hot-pressing sintering with MgSiN{sub 2}-Y{sub 2}O{sub 3} or only MgSiN{sub 2} as sintering aids. The influences of the amount of MgSiN{sub 2} and Y{sub 2}O{sub 3} and sintering methods on the properties of Si{sub 3}N{sub 4} ceramics were investigated. The results show that the bend strength of Si{sub 3}N{sub 4} ceramic fabricated through pressureless sintering at 1820 deg. C for 4 h with 5.6 wt.% MgSiN{sub 2}-15.8 wt.% Y{sub 2}O{sub 3} as sintering additive could achieve 839 MPa. However, the bend strength of Si{sub 3}N{sub 4} ceramic produced by hot-pressing sintering at 1750 deg. C for 1 h under uniaxial pressure of 20 MPa with 4.76 wt.% MgSiN{sub 2} was 1149 MPa. The thermal conductivity of the Si{sub 3}N{sub 4} ceramic 2 3 4 could reach to 129 W{center_dot}m{sup -1{center_dot}}K{sup 1}. The present work demonstrated that MgSiN{sub 2} aids and hot-pressing sintering were effective to improve the thermal conductivity of Si{sub 3}N{sub 4} ceramic.

  20. Yttrium oxide transparent ceramics by low-temperature microwave sintering

    International Nuclear Information System (INIS)

    Luo, Junming; Zhong, Zhenchen; Xu, Jilin

    2012-01-01

    Graphical abstract: The figure shows the SEM photos of the surfaces of the Y 2 O 3 transparent ceramic samples obtained by microwave sintering and vacuum sintering. It is clearly demonstrated that the grain distribution of the vacuum sintering sample is not uniform with the smallest and the largest particle size at about 2 μm and 15 μm respectively, while the grain distribution of microwave sintering sample is uniform with the average diameter at about 2–4 μm (the smallest reported so far) and with no abnormal growth-up or coarsening phenomenon. We have further found out that the smaller the grain size, the higher the mechanical and optical properties. Display Omitted Highlights: ► The microwave sintering temperature of the sample is lower compared with vacuum. ► The microwave sintering time of the sample is shorter compared with vacuum. ► The mechanical properties of the microwave sintering sample is improved greatly. ► The Y 2 O 3 grain of microwave sintering sample is the smallest reported so far. -- Abstract: Yttrium oxide (Y 2 O 3 ) transparent ceramics samples have been successfully fabricated by microwave sintering processing at relatively low temperatures. In comparison with the vacuum sintering processing, Y 2 O 3 transparent ceramics can be obtained by microwave sintering at lower sintering temperature and shorter sintering time, and they possess higher transmittances and mechanical properties. The technologies of low-temperature microwave sintering and the relationships of the microstructures and properties of the specified samples have been investigated in detail. We have found out that the low-temperature microwave sintering technique has its obvious advantages over the conventional methods in manufacturing yttrium oxide transparent ceramics.

  1. Improvement of paint effluents coagulation using natural and synthetic coagulant aids.

    Science.gov (United States)

    Aboulhassan, M A; Souabi, S; Yaacoubi, A; Baudu, M

    2006-11-02

    The coagulant iron chloride and the flocculants Polysep 3000 (PO), Superfloc A-1820 (SU) and Praestol 2515 TR (PR) have been used in this study to show the efficiency of coagulation flocculation process in the chemical precipitation method for the removal of organic and colouring matters from the paint industry wastewater. This study also includes the amount of produced sludge. The results indicate that FeCl(3) is efficient at pH range 8-9 and at optimal dose of 650 mgl(-1). Iron chloride allows the removal of 82% of chemical oxygen demand (COD) and 94% of colour. However, sequential addition of coagulant and polymeric additives enhance clearly pollutant removal and produces less decanted sludge compared to the results obtained when the coagulant is used alone. The removal efficiency of COD reaches 91% and that of colour 99%. Coagulation-biflocculation process is more effective than the coagulation-monoflocculation one. The sequential addition of iron chloride, Polysep 3000 (cationic flocculant) and Praestol 2515 TR (anionic flocculant) seems to be the most suitable combination for the treatment of the paint industry wastewaters.

  2. Analysis of the demagnetization process of Nd-Fe-B sintered magnets at elevated temperatures by magnetic domain observation using a Kerr microscope

    Science.gov (United States)

    Takezawa, M.; Ogimoto, H.; Kimura, Y.; Morimoto, Y.

    2014-05-01

    Magnetization reversal and its propagation in sintered Nd-Fe-B magnets were clearly observed at elevated temperatures up to 150 °C using a Kerr microscope, image processing, and photo editing. Simultaneous magnetization reversal in several grains along the easy axis direction occurred at elevated temperature, and the extent of simultaneous magnetization reversal increased with temperature. This indicates that reduction in the coercivity of Nd-Fe-B sintered magnets at elevated temperatures is attributable to decrease in anisotropy and insufficient pinning of domain walls at grain boundaries.

  3. TiO2 doped UO2 fuels sintered by spark plasma sintering

    Science.gov (United States)

    Yao, Tiankai; Scott, Spencer M.; Xin, Guoqing; Lian, Jie

    2016-02-01

    UO2 fuels doped with oxide additives Cr2O3 and TiO2 display larger grain size, improving fission product retention capability and thus accident tolerance. Spark plasma sintering (SPS) was applied to consolidate TiO2-doped UO2 fuel pellets with 0.5 wt % dopant concentration, above its solubility, in order to induce eutectic phase formation and promote sintering kinetics. The grain size can reach 80 μm by sintering at 1700 °C for 20 min, and liquid U-Ti-O eutectic phase occurs at the triple junction of grain boundaries and significantly improves grain growth during sintering. The oxide additive also impedes the reduction of the initial hyperstoichiometric fuel powders to more stoichiometric fuel pellets upon SPS process. Thermal-mechanical properties of the sintered doped fuel pellets including thermal conductivity and hardness are measured and compared with undoped fuel pellets. The enlarged grain size (80 μm) and densification within short sintering duration highlight the immense possibility of SPS in fabricating large grained UO2 fuel pellets to improve fuel performance.

  4. Role of sintering time, crystalline phases and symmetry in the piezoelectric properties of lead-free KNN-modified ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Rubio-Marcos, F., E-mail: frmarcos@icv.csic.es [Electroceramic Department, Instituto de Ceramica y Vidrio, CSIC, Kelsen 5, 28049 Madrid (Spain); Marchet, P.; Merle-Mejean, T. [SPCTS, UMR 6638 CNRS, Universite de Limoges, 123, Av. A. Thomas, 87060 Limoges (France); Fernandez, J.F. [Electroceramic Department, Instituto de Ceramica y Vidrio, CSIC, Kelsen 5, 28049 Madrid (Spain)

    2010-09-01

    Lead-free KNN-modified piezoceramics of the system (Li,Na,K)(Nb,Ta,Sb)O{sub 3} were prepared by conventional solid-state sintering. The X-ray diffraction patterns revealed a perovskite phase, together with some minor secondary phase, which was assigned to K{sub 3}LiNb{sub 6}O{sub 17}, tetragonal tungsten-bronze (TTB). A structural evolution toward a pure tetragonal structure with the increasing sintering time was observed, associated with the decrease of TTB phase. A correlation between higher tetragonality and higher piezoelectric response was clearly evidenced. Contrary to the case of the LiTaO{sub 3} modified KNN, very large abnormal grains with TTB structure were not detected. As a consequence, the simultaneous modification by tantalum and antimony seems to induce during sintering a different behaviour from the one of LiTaO{sub 3} modified KNN.

  5. Sintering uranium oxide using a preheating step

    International Nuclear Information System (INIS)

    Jensen, N.J.; Nivas, Y.; Packard, D.R.

    1977-01-01

    Compacted pellets of uranium oxide or uranium oxide with one or more additives are heated in a kiln in a process having a preheating step, a sintering step, a reduction step, and a cooling step in a controlled atmosphere. The process is practiced to give a range of temperature and atmosphere conditions for obtaining optimum fluoride removal from the compacted pellets along with optimum sintering in a single process. The preheating step of this process is conducted in a temperature range of about 600 0 to about 900 0 C and the pellets are held for at least twenty min, and preferably about 60 min, in an atmosphere having a composition in the range of about 10 to about 75 vol % hydrogen with the balance being carbon dioxide. The sintering step is conducted at a temperature in the range of about 900 0 C to 1500 0 C in the presence of an atmosphere having a composition in the range of about 0.5 to about 90 vol % hydrogen with the balance being carbon dioxide. The reduction step reduces the oxygen to metal ratio of the pellets to a range of about 1.98 to 2.10:1 and this is accomplished by gradually cooling the pellets for about 30 to about 120 min from the temperature of the sintering step to about 1100 0 C in an atmosphere of about 10 to 90 vol % hydrogen with the balance being carbon dioxide. Thereafter the pellets are cooled to about 100 0 C under a protective atmosphere, and in one preferred practice the same atmosphere used in the reduction step is used in the cooling step. The preheating, sintering and reduction steps may also be conducted with their respective atmospheres having an initial additional component of water vapor and the water vapor can comprise up to about 20 vol %

  6. Comparative sinterability of combustion synthesized and commercial titanium carbides

    International Nuclear Information System (INIS)

    Manley, B.W.

    1984-11-01

    The influence of various parameters on the sinterability of combustion synthesized titanium carbide was investigaged. Titanium carbide powders, prepared by the combustion synthesis process, were sintered in the temperature range 1150 to 1600 0 C. Incomplete combustion and high oxygen contents were found to be the cause of reduced shrinkage during sintering of the combustion syntheized powders when compared to the shrinkage of commercial TiC. Free carbon was shown to inhibit shrinkage. The activation energy for sintering was found to depend on stoichiometry (C/Ti). With decreasing C/Ti, the rate of sintering increased. 29 references, 16 figures, 13 tables

  7. Phase transformation of NiTi alloys during vacuum sintering

    Science.gov (United States)

    Wang, Jun; Hu, Kuang

    2017-05-01

    The aim of this study is to ascertain the Phase transformation of NiTi alloys during vacuum sintering. NiTi shape memory alloys (SMA) of atomic ratio 1:1 were prepared through press forming and vacuum sintering with the mixture of Ni and Ti powders. Different samples were prepared by changing the sintering time and the sintering temperature. Phase and porosity of the samples were investigated by X-ray diffraction (XRD) and scanning electron microscope (SEM). The results show that in the process of sintering NiTi2 and Ni3Ti phases are formed firstly and then transform into NiTi phase. The quantity of NiTi2 and Ni3Ti phases gradually decreased but not eliminate completely with increase of sintering time. The porosity of specimen sintering at 900°C decreases slightly with increase of sintering time. With increase of sintering time the porosity of specimen sintering at 1050°C decreased firstly and then increased because of generation rich titanium liquid in the process of sintering.

  8. Reactive sintering of TiAl–Ti5Si3 in situ composites

    Energy Technology Data Exchange (ETDEWEB)

    Alman, David E.

    2005-06-01

    TiAl with between 0 and 20 vol%Ti5Si3 was produced by reactive sintering (700 °C for 15 min in vacuum) of cold pressed compacts of elemental Ti, Al and Si powder. The results show that adding Si to Ti and Al reduces the swelling associated with reactive sintering of TiAl, as composites containing more than 5 vol%Ti5Si3 densified during reactive sintering. However, composites containing more than 10 vol%Ti5Si3 did not retain their shape and the TiAl+20 vol%Ti5Si3 composite completely melted during the sintering process. A thermodynamic analysis indicated that the simultaneous formation of TiAl and Ti5Si3 increases the adiabatic flame temperature during the reaction between the powders. In fact, the analysis predicted that the maximum temperature of the reaction associated with the formation TiAl+20 vol%Ti5Si3 should exceed the melting point of TiAl, and this was observed experimentally. Differential thermal analysis (DTA) revealed that an Al–Si eutectic reaction occurred in mixtures of Ti, Al and Si powders prior to the formation of the TiAl and Ti5Si3 phases. There was no such pre-reaction formation of a eutectic liquid in Ti and Al powder mixtures. The formation of the pre-reaction liquid and the increase in adiabatic flame temperature resulted in the melting that occurred and the enhanced densification (minimization of swelling) during reactive sintering of the in situ composites.

  9. Spark plasma sintering of hydrothermally synthesized bismuth ferrite

    Directory of Open Access Journals (Sweden)

    Zorica Branković

    2016-12-01

    Full Text Available Bismuth ferrite, BiFeO3 (BFO, powder was synthesized by hydrothermal method from Bi(NO33·5 H2O and Fe(NO33·9 H2O as precursors. The synthesized powder was further sintered using spark plasma sintering (SPS. The sintering conditions were optimized in order to achieve high density, minimal amount of secondary phases and improved ferroelectric and magnetic properties. The optimal structure and properties were achieved after spark plasma sintering at 630 °C for 20 min, under uniaxial pressure of 90 MPa. The composition, microstructure, ferroelectric and magnetic properties of the SPS samples were characterized and compared to those of conventionally sintered ceramics obtained from the same powder. Although the samples sintered using conventional method showed slightly lower amount of secondary phases, the spark plasma sintered samples exhibited favourable microstructure and better ferroelectric properties.

  10. Evaluation of the Particle Bonding for Aluminum Sample Produced by Spark Plasma Sintering

    Science.gov (United States)

    Tünçay, Mehmet Masum; Nguyen, Lucie; Hendrickx, Philippe; Brochu, Mathieu

    2016-10-01

    Spark plasma sintering (SPS) is a powder metallurgy process that sinters powder materials within a short time by simultaneous application of electrical current and pressure. SPS differs from other conventional powder metallurgy processes by its heating mechanism, which is Joule heating of the sample within a graphite die. This study investigates the consolidation of aluminum powder by SPS. Different pressures were used and particle bonding evaluated by means of fracture surface analysis. Electrical resistance, obtained from online monitoring of the variation of voltage and current during the process, showed an enhanced descent at 0.3 T m, and the area under this drop was associated with ductility: the greater the area, the higher the ductility. This temperature corresponds to a significant increase in the hardness ratio of the oxide layer to aluminum, where breakdown of the oxide layer becomes easier, permitting enhanced metallurgical bonding between the powder particles.

  11. Numerical simulation of electric field assisted sintering

    Science.gov (United States)

    McWilliams, Brandon A.

    A fully coupled thermal-electric-sintering finite element model was developed and implemented to explore electric field assisted sintering techniques (FAST). FAST is a single step processing operation for producing bulk materials from powders, in which the powder is heated by the application of electric current under pressure. This process differs from other powder processing techniques such as hot isostatic pressing (HIP) and traditional press and sinter operations where the powder or compact is heated externally, in that the powder is heated directly as a result of internal Joule heating (for conductive powders) and/or by direct conduction from the die and punches. The overall result is much more efficient heating which allows heating rates of >1000°C/min to be achieved which is desirable for sintering bulk nanocrystalline and other novel high performance materials. Previous modeling efforts on FAST have only considered the thermal-electric aspect of the problem and have neglected densification. In addition to the introduction of a sintering model, a detailed thermal-electric study of process parameters was carried out in order to identify key system variables and quantify their effect on the overall system response and subsequent thermal history of a consolidated sample. This analysis was compared to empirical data from a parallel experimental study and shown to satisfactorily predict the observed trends. This model was then integrated with a phenomenologically based sintering model to capture the densification of the sample. This fully coupled model was used to predict densification kinetics under FAST like conditions and examine the evolution of material properties as the sample transitions from a loose powder to a fully dense compact and the resulting effect on the electrical and thermal fields within the compact. This model was also used to explore the effect of non-uniform thermal, electrical, stress and density fields on the final geometry and local

  12. Evaluation of the process of coagulation/flocculation of produced water using Moringa oleifera Lam. as natural coagulant

    Energy Technology Data Exchange (ETDEWEB)

    Santana, C.R.; Pereira, D.F.; Sousa, S.C S N.; Silva, G.F. [Universidade Federal de Sergipe (UFSE), Sao Cristovao, SE (Brazil). Dept. de Engenharia Quimica], e-mail: claudia@ufs.br; Cavalcanti, E.B. [Universidade Tiradentes (UNIT), SE (Brazil). Inst. de Tecnologia e Pesquisa

    2010-07-15

    In the lifetime of an oil well, there comes a moment when a lot of water begins to be produced along with oil, either by the conditions of the reservoir, or as a result of water injection in the secondary recovery of the well. An important step in such process involves the treatment of the produced water by means of coagulation techniques. Therefore, the use of environmentally correct coagulants is presented as a viable alternative and has demonstrated advantages over the use of chemical coagulants. The plant of the genus Moringa, whose species is oleifera Lam, stands out as one of the most promising natural coagulants. The present study investigated the evaluation of the coagulation/flocculation of produced water, using seeds of Moringa oleifera Lam. as coagulant. The results were very significant, demonstrating that Moringa oleifera Lam. can be used as a natural coagulant in this type of treatment. (author)

  13. Ventricular metastasis resulting in disseminated intravascular coagulation

    Directory of Open Access Journals (Sweden)

    Davis Ian D

    2005-05-01

    Full Text Available Abstract Background Disseminated Intravascular Coagulation (DIC complicates up to 7% of malignancies, the commonest solid organ association being adenocarcinoma. Transitional Cell Carcinoma (TCC has rarely been associated with DIC. Case presentation A 74-year-old woman with TCC bladder and DIC was found to have a cardiac lesion suspicious for metastatic disease. The DIC improved with infusion of plasma and administration of Vitamin K, however the cardiac lesion was deemed inoperable and chemotherapy inappropriate; given the patients functional status. We postulate that direct activation of the coagulation cascade by the intraventricular metastasis probably triggered the coagulopathy in this patient. Conclusion Cardiac metastases should be considered in cancer patients with otherwise unexplained DIC. This may influence treatment choices.

  14. Coagulation and morbidity in treated HIV infection

    Science.gov (United States)

    Funderburg, Nicholas T.; Lederman, Michael M.

    2014-01-01

    HIV infected patients are at increased risk for venous and arterial thromboembolic events. Multiple markers related to inflammation (IL-6, TNFrI, C-reative protein) and coagulation (tissue factor expression, FVIII, thrombin, fibrinogen and D-dimer levels) are increased in HIV infection, and several are predictive of thrombotic risk and mortality in HIV disease. The mechanisms behind the risk for abnormal coagulation in HIV infection have not been fully elucidated, but may be related to a chronic immune activation and inflammatory state in both untreated and treated HIV infection. The contribution of traditional risk factors, including smoking and dyslipidemia, overly represented in HIV infected patients, must also be considered when assessing thrombotic risk in this setting. Currently, several interventional studies are aimed at reducing inflammation and cardiovascular risk in HIV disease and may provide insights into the determinants of clotting events in HIV infected patients. PMID:24759134

  15. Foaming Glass Using High Pressure Sintering

    DEFF Research Database (Denmark)

    Østergaard, Martin Bonderup; Petersen, Rasmus Rosenlund; König, Jakob

    Foam glass is a high added value product which contributes to waste recycling and energy efficiency through heat insulation. The foaming can be initiated by a chemical or physical process. Chemical foaming with aid of a foaming agent is the dominant industrial process. Physical foaming has two...... variations. One way is by saturation of glass melts with gas. The other involves sintering of powdered glass under a high gas pressure resulting in glass pellets with high pressure bubbles entrapped. Reheating the glass pellets above the glass transition temperature under ambient pressure allows the bubbles...... to expand. After heat-treatment foam glass can be obtained with porosities of 80–90 %. In this study we conduct physical foaming of cathode ray tube (CRT) panel glass by sintering under high pressure (5-25 MPa) using helium, nitrogen, or argon at 640 °C (~108 Pa s). Reheating a sample in a heating...

  16. Sintering techniques for microstructure control in ceramics

    Science.gov (United States)

    Rosenberger, Andrew T.

    Sintering techniques can be manipulated to enhance densification in difficult to sinter materials and to produce property enhancing microstructures. However, the interplay between materials, sintering techniques, and end properties is not fully understood in many material systems, and some fundamental aspects of sintering such as the nature of the effects of electric fields remains unknown. The processing property relationships were examined in two classes of materials; zirconium diboride ultra high temperature ceramic composites, and all solid lithium-ion battery phosphate materials. Investigation of zirconium diboride ceramics focused on the effects of zirconium carbide as a secondary or tertiary phase in ZrB2 and ZrB2 -- SiC. Addition of zirconium carbide was observed to increase flexural strength of composites up to 590MPa at 50wt% ZrC, significantly higher than the flexural strength of 380MPa observed in similarly prepared ZrB2 -- SiC. This difference was attributed to the absence of CTE mismatch induced residual stresses in the ZrB2 -- ZrC composites. A high temperature reaction between ZrB2 and TiC producing Zr1-xTixB2 -- ZrC composites was discovered and found to enhance densification while reducing the average grain size to as small as 1.4mum, lower than the starting powder size of 1.8mum. While a high flexural strength of 670MPa was observed, a strength dependence on the ZrC grain size indicative of CTE mismatch residual stresses was also seen. Finally, the oxidation and ablation resistance of ZrB2 -- ZrC -- SiC composites as a function of ZrC fraction and ZrC:SiC ratio was investigated. Above 5vol% ZrC, the oxidation and ablation resistance of the composites was significantly reduced due to ZrC oxidation, regardless of SiC content. While ZrC can significantly enhance the mechanical properties of the composite, the volume fraction must be kept low to avoid an undesirable reduction in the oxidation resistance. The influence of applied electrical fields

  17. Reaction sintering of ceramic-metal composites

    International Nuclear Information System (INIS)

    Botta Filho, W.J.; Rodrigues, J.A.; Tomasi, R.; Pandolfelli, V.C.; Passos, J.F.S.S.; Folgueras, M.V.

    1990-01-01

    Reaction sintering experiments have been carried out in the system Al 2 O 3 -ZrAl 2 -Nb 2 O 5 with the objective of producing ceramic-metal composites of improved toughness. The sintering treatments have been done in the temperature range of 700 0 C to 1400 0 C under different conditions of vacuum and in air and argon atmospheres. The treated samples have been analysed by X-ray diffraction and analytical electron microscopy. The results are discussed in function of the degree of reaction, the development of microstructure and the densification. These results have shown that although an exchange reaction can occur to produce a composite, the control of the reaction to obtain a dense microstructure has not been possible yet. (author) [pt

  18. Coagulation of sheep intestinal and prefemoral lymph.

    Science.gov (United States)

    Hanley, C A; Johnston, M G; Nelson, W

    1988-06-01

    We have determined the most suitable method for the automated analysis of the clotting parameters in sheep intestinal and prefemoral lymph as defined by the Activated Partial Thromboplastin Times (APTT; measure of intrinsic coagulation pathway) and the Prothrombin Times (PT; measure of extrinsic coagulation pathway). As opposed to optical density systems, the use of a Fibro-System Fibrometer was found to provide the most consistent assessment of coagulation with the endpoint being the time to fibrin strand formation. We measured APTT in sheep intestinal and prefemoral lymph of 59.78 +/- 7.69 seconds and 51.03 +/- 10.49 seconds respectively. These values were more prolonged than those obtained from sheep blood plasma but only in the case of intestinal lymph were the differences significant (p less than 0.025). Human blood APTT values were significantly less than both sheep blood (p less than 0.05) and sheep intestinal (p less than 0.001) and prefemoral lymph (p less than 0.01). PT values were found to be 21.56 +/- 1.14 seconds in intestinal and 22.00 +/- 1.88 seconds in prefemoral lymph. These values were also significantly greater than those obtained from sheep blood (both p less than 0.001). Human blood PTs were significantly less than both sheep blood (p less than 0.001) and intestinal and prefemoral lymph (both p less than 0.001). Measurement of APTT and PT values in intestinal lymph and PT determinations in prefemoral lymph were not affected by storage in the refrigerator or freezer. There was some indication that APTT values in prefemoral samples were susceptible to storage artifacts; however, the differences in coagulation times were not significant.

  19. Thymoquinone Modulates Blood Coagulation in Vitro via Its Effects on Inflammatory and Coagulation Pathways

    Science.gov (United States)

    Muralidharan-Chari, Vandhana; Kim, Jaehan; Abuawad, Ahlam; Naeem, Mubeena; Cui, Huadong; Mousa, Shaker A.

    2016-01-01

    Thymoquinone (THQ) is a major component of black seeds. Given that both THQ and black seeds exhibit anti-cancer and anti-inflammatory activities, we hypothesized that THQ will affect cancer-associated thrombosis (CAT), which is primarily triggered by tissue factor (TF) and inflammation. The effect of both black seed-extracted and purchased (“pure”) THQ on normal blood coagulation was tested with in vitro thromboelastography (TEG) and activated partial thromboplastin time (aPTT) coagulation assays. The effect of pure THQ on CAT was tested with aPTT assay using pancreatic cancer cell lines that are either positive or negative for TF, and with TEG assay using lipopolysaccharide as an inflammatory trigger. Additionally, the direct effect of THQ on the inactivation of factors IIa and Xa was assessed. Since TNF-α facilitates crosstalk between inflammation and thrombosis by triggering the NF-κB pathway, we tested THQ’s ability to interfere with this communication with a luciferase assay. Both extracted and pure THQ had minimal effects on normal blood coagulation. Pure THQ reversed CAT initiated by both TF and inflammation to basal levels (p coagulation and can reverse CAT in vitro, possibly by interfering with the crosstalk between inflammation and coagulation. This study suggests the utility of THQ as a preventative anticoagulant and/or as a supplement to existing chemotherapies and anticoagulant therapies. PMID:27043539

  20. Sintering Behavior, Microstructure, and Mechanical Properties: A Comparison among Pressureless Sintered Ultra-Refractory Carbides

    Directory of Open Access Journals (Sweden)

    Laura Silvestroni

    2010-01-01

    Full Text Available Nearly fully dense carbides of zirconium, hafnium, and tantalum were obtained by pressureless sintering at 1950°C with the addition of 5–20 vol% of MoSi2. Increasing the amount of sintering aid, the final density increased too, thanks to the formation of small amounts of liquid phase constituted by M-Mo-Si-O-C, where M is either Zr, Hf, or Ta. The matrices of the composites obtained with the standard procedure showed faceted squared grains; when an ultrasonication step was introduced in the powder treatment, the grains were more rounded and no exaggerated grains growth occurred. Other secondary phases observed in the microstructure were SiC and mixed silicides of the transition metals. Among the three carbides prepared by pressurless sintering, TaC-based composites had the highest mechanical properties at room temperature (strength 590 MPa, Young's modulus 480 GPa, toughness 3.8 MPa·m1/2. HfC-based materials showed the highest sinterability (in terms of final density versus amount of sintering aid and the highest high-temperature strength (300 MPa at 1500  °C.

  1. Fabrication of Sintered Annular Fuel Pellet

    International Nuclear Information System (INIS)

    Rhee, Young Woo; Kim, Dong Joo; Kim, Jong Hun; Yang, Jae Ho; Kim, Keon Sik; Kang, Ki Won; Song, Kun Woo

    2010-01-01

    A dual cooled annular fuel has been seriously considered as a favorable option for uprating the power density of a Pressurized Water Reactor fuel assembly. An annular fuel has a geometrically inherent advantage such as an increased heat transfer area and a thin pellet thickness. It results in a lot of advantages from the point of a fuel safety and its economy. In order to actualize the dual cooled fuel, an essential element is the annular pellet with precisely controlled diametric tolerance. However, the unique shape of annular fuel pellet causes challenging difficulties to satisfy a diametric tolerance specification. Because of an inhomogeneous green density distribution along the compact height, an hour-glassing usually occurred in a sintered cylindrical PWR fuel pellet fabricated by a conventional doubleacting press. Thus, a sintered pellet usually undergoes a centerless grinding process in order to secure a pellet's specifications. In the case of an annular pellet fabrication using a conventional double-acting press, the same hour-glass shape would probably occur. The outer diameter tolerance of an annular pellet can be controlled easily similar to that of a conventional cylindrical PWR pellet through a centerless grinding. However, it appears not to be simple in the case of an inner surface grinding. It would be the best way to satisfy the specifications for the inner diameter in an as-fabricated pellet. In the present study, we are trying to find a way to minimize the diametric tolerance of the sintered annular pellet without inner surface grinding. This paper deals with a new approach that we have tried to reduce the diametric tolerance of the sintered annular pellet

  2. Exact combinatorial approach to finite coagulating systems

    Science.gov (United States)

    Fronczak, Agata; Chmiel, Anna; Fronczak, Piotr

    2018-02-01

    This paper outlines an exact combinatorial approach to finite coagulating systems. In this approach, cluster sizes and time are discrete and the binary aggregation alone governs the time evolution of the systems. By considering the growth histories of all possible clusters, an exact expression is derived for the probability of a coagulating system with an arbitrary kernel being found in a given cluster configuration when monodisperse initial conditions are applied. Then this probability is used to calculate the time-dependent distribution for the number of clusters of a given size, the average number of such clusters, and that average's standard deviation. The correctness of our general expressions is proved based on the (analytical and numerical) results obtained for systems with the constant kernel. In addition, the results obtained are compared with the results arising from the solutions to the mean-field Smoluchowski coagulation equation, indicating its weak points. The paper closes with a brief discussion on the extensibility to other systems of the approach presented herein, emphasizing the issue of arbitrary initial conditions.

  3. Coagulation factor XII in thrombosis and inflammation.

    Science.gov (United States)

    Maas, Coen; Renné, Thomas

    2018-02-26

    Combinations of proinflammatory and procoagulant reactions are the unifying principle for a variety of disorders affecting the cardiovascular system. The factor XII-driven-contact system starts coagulation and inflammatory mechanisms via the intrinsic pathway of coagulation and the bradykinin-producing kallikrein-kinin system, respectively. The biochemistry of the contact system in vitro is well understood, however its in vivo functions are just beginning to emerge. Challenging the concept of the coagulation balance, targeting factor XII or its activator polyphosphate provides protection from thromboembolic diseases without interfering with hemostasis. This suggests that the polyphosphate/factor XII axis contributes to thrombus formation while being dispensable for hemostatic processes. In contrast to deficiency in factor XII providing safe thromboprotection, excessive FXII activity is associated with the life-threatening inflammatory disorder hereditary angioedema. The current review summarizes recent finding of the polyphosphate/factor XII-driven contact system at the intersection of procoagulant and proinflammatory disease states. Elucidating the contact system offers the exciting opportunity to develop strategies for safe interference with both thrombotic and inflammatory disorders. Copyright © 2018 American Society of Hematology.

  4. Disseminated intravascular coagulation in solid tumors

    International Nuclear Information System (INIS)

    Terzieff, V.; Alonso, I.; Vázquez, A.

    2004-01-01

    It is estimated that 20-25% of cases of disseminated intravascular coagulation (DIC) relate to an underlying neoplasia primarily hematologic. It is estimated that about 5% of patients with solid tumors have CID clinic, although the incidence of subclinical alterations is much higher. The CID is not limited to the activation of the coagulation cascade, which leads to bleeding micro thrombosis and consumption of coagulation factors. Solid tumors are frequently associated adenocarcinomas producers mucin (especially gastric), usually in the context of a disseminated disease. The mucin may act as a promoter of the cascade, but probably it is a multi-event. High levels of TNF to produced by the tumor mass and chemotherapy-induced cell lysis have Also linked. Although the bleeding is usually oriented diagnosis, the most frequent cause of death is thrombosis. There are no specific tests for diagnosis. Elevated levels of D-dimer and products oriented fibrinogen degradation diagnosis. No reduction fibrinogen and almost always, one thrombocytopenia consumption. Treatment is complex and there is no consensus on many points. To recover the lost factors for consumption, it is recommended to use fresh frozen plasma and / or washed red blood cells. the heparin anticoagulation low dose is indicated since the disease causal can not be controlled quickly, but should not be initiated if there thrombocytopenia 50.000.El under profuse bleeding can require the use of tranexamic acid or EACA. Acute DIC, the case of our patient, is rare and very serious

  5. Imaging of blood plasma coagulation at supported lipid membranes.

    Science.gov (United States)

    Faxälv, Lars; Hume, Jasmin; Kasemo, Bengt; Svedhem, Sofia

    2011-12-15

    The blood coagulation system relies on lipid membrane constituents to act as regulators of the coagulation process upon vascular trauma, and in particular the 2D configuration of the lipid membranes is known to efficiently catalyze enzymatic activity of blood coagulation factors. This work demonstrates a new application of a recently developed methodology to study blood coagulation at lipid membrane interfaces with the use of imaging technology. Lipid membranes with varied net charges were formed on silica supports by systematically using different combinations of lipids where neutral phosphocholine (PC) lipids were mixed with phospholipids having either positively charged ethylphosphocholine (EPC), or negatively charged phosphatidylserine (PS) headgroups. Coagulation imaging demonstrated that negatively charged SiO(2) and membrane surfaces exposing PS (obtained from liposomes containing 30% of PS) had coagulation times which were significantly shorter than those for plain PC membranes and EPC exposing membrane surfaces (obtained from liposomes containing 30% of EPC). Coagulation times decreased non-linearly with increasing negative surface charge for lipid membranes. A threshold value for shorter coagulation times was observed below a PS content of ∼6%. We conclude that the lipid membranes on solid support studied with the imaging setup as presented in this study offers a flexible and non-expensive solution for coagulation studies at biological membranes. It will be interesting to extend the present study towards examining coagulation on more complex lipid-based model systems. Copyright © 2011 Elsevier Inc. All rights reserved.

  6. Sintering of titanium alloy by powder metallurgy

    Energy Technology Data Exchange (ETDEWEB)

    Cosme, C.R.M. [Universidade de Brasilia (UnB), DF (Brazil); Henriques, V.A.R.; Cairo, C.A.A.; Taddei, E.B. [Centro Tecnico Aeroespacial (CTA), Sao Jose dos Campos, SP (Brazil)

    2009-07-01

    Full text: Titanium alloys are suitable for biomaterial applications, considering its biocompatibility and low elastic modulus compared to steel. Bone resorption in this case can be reduced by load sharing between the implant and natural bone.Starting powders were obtained by hydride method, carried out under positive hydrogen pressure at 500 deg C for titanium and 800 deg C for Nb, Zr and Ta powders. After reaching the nominal temperature, the material was held for 3h, with subsequent cooling to room temperature and milling of the friable hydride. Samples were produce by mixing of initial metallic powders followed by and cold isostatic pressing. Subsequent densification by sintering was performed at temperature range between 900 and 1700 deg C. Characterization was carried out with scanning electron microscopy, X-ray diffractometry and microhardness measurements. Microstructural examinations revealed higher amount of &⧣946;-phase for higher sintering temperature and dissolution of Ta and NB particles. In vitro tests revealed low cytotoxicity of sintered samples. (author)

  7. Sintering and deformation of nanocrystalline ceramics

    International Nuclear Information System (INIS)

    Hahn, H.; Averback, R.S.; Hofler, H.J.; Logas, J.

    1991-01-01

    Nanocrystalline ceramics have been produced by the method of inert gas condensation of ultra-small particles and in situ consolidation. Sintering characteristics and microstructural parameter such as grain size, porosity and pore size distributions have been investigated by a variety of techniques, including: X-ray diffraction, gravimetry, nitrogen adsorption, scanning electron microscopy and small angle neutron scattering. In pure TiO 2 , the sintering temperatures are drastically lowered compared to conventional ceramics, however, extensive grain growth occurs before full densification is achieved. High density, nanocrystalline ceramics can be prepared by pressure assisted sintering, doping and additions of second phases. High temperature microhardness and creep deformation in compression were measured and it was found that creep processes occur at lower temperatures than in ceramics with larger grain sizes. Nanocrystalline TiO 2 with densities >99% can be deformed plastically without fracture at temperatures below half the melting point. The total strains exceed 0.6 at strain rates as high as 10 -3 s -l . The stress exponent of the strain rate, n, is approximately 3 and the grain size dependence is G -q with q in the range of 1-1.5. In this paper it is concluded that the creep deformation occurs by an interface reaction controlled mechanism

  8. Basic characteristics of Australian iron ore concentrate and its effects on sinter properties during the high-limonite sintering process

    Science.gov (United States)

    Liu, Dong-hui; Liu, Hao; Zhang, Jian-liang; Liu, Zheng-jian; Xue, Xun; Wang, Guang-wei; Kang, Qing-feng

    2017-09-01

    The basic characteristics of Australian iron ore concentrate (Ore-A) and its effects on sinter properties during a high-limonite sintering process were studied using micro-sinter and sinter pot methods. The results show that the Ore-A exhibits good granulation properties, strong liquid flow capability, high bonding phase strength and crystal strength, but poor assimilability. With increasing Ore-A ratio, the tumbler index and the reduction index (RI) of the sinter first increase and then decrease, whereas the softening interval (Δ T) and the softening start temperature ( T 10%) of the sinter exhibit the opposite behavior; the reduction degradation index (RDI+3.15) of the sinter increases linearly, but the sinter yield exhibits no obvious effects. With increasing Ore-A ratio, the distribution and crystallization of the minerals are improved, the main bonding phase first changes from silico-ferrite of calcium and aluminum (SFCA) to kirschsteinite, silicate, and SFCA and then transforms to 2CaO·SiO2 and SFCA. Given the utilization of Ore-A and the improvement of the sinter properties, the Ore-A ratio in the high-limonite sintering process is suggested to be controlled at approximately 6wt%.

  9. Coagulation performance of a novel poly-ferric-acetate (PFC) coagulant in phosphate-kaolin synthetic water treatment

    Energy Technology Data Exchange (ETDEWEB)

    Wei, Yanxin; Lu, Jinpeng; Dong, Xiongzi; Yao, Chengli [Hefei Normal University, Hefei (China); Hao, Jianwen [Anhui Vocational and Technical College, Hefei (China)

    2017-10-15

    The process of coagulation-flocculation is increasingly applied in wastewater treatment. And the polymerized inorganic coagulants are widely used among these coagulation-flocculation processes. However, conventional coagulants using sulfates or chlorides as counter anion may give rise to corrosion. The purpose of this study was to synthesize PFC coagulants in which acetate is used as counter anion. The influences on the preparation of PFC were optimized. The synthesis was done at the optimum conditions, such as temperature of 60 .deg. C, the Fe/CH{sub 3}COOH molar ratio of 1 : 4.0 and reaction time of 6 h, respectively. The prepared PFC coagulants were characterized by Fourier transform infrared (FTIR) spectrophotometry and scanning electron microscopy (SEM). PFC was found to mainly form complexation polymeric species and present more cluster and lamellar structure. A series of jar tests were carried out to study the coagulation performance of PFC and PFS in phosphate-kaolin synthetic water treatment. Results showed that the coagulation performance of PFC was more efficient than PFS's in terms of the phosphorus removal efficiency and the residual turbidity. Due to using acetate as counter anion to iron, PFC is less harmful to the processes of water treatment and equipment than that of the conventional coagulants applied chlorides or sulfates. Therefore, PFC is a promising coagulant in the process of corrosion sensitive applications and the process of wastewater containing phosphorus treatment.

  10. Ozonation and/or Coagulation - Ceramic Membrane Hybrid for Filtration of Impaired-Quality Source Waters

    KAUST Repository

    Ha, Changwon

    2013-09-01

    When microfiltration (MF) and ultrafiltration (UF) membranes are applied for drinking water treatment/wastewater reuse, membrane fouling is an evitable problem, causing the loss of productivity over time. Polymeric membranes have been often reported to experience rapid and/or problematical fouling, restraining sustainable operation. Ceramic membranes can be effectively employed to treat impaired-quality source waters due to their inherent robustness in terms of physical and chemical stability. This research aimed to identify the effects of coagulation and/or ozonation on ceramic membrane filtration for seawater and wastewater (WW) effluent. Two different types of MF and UF ceramic membranes obtained by sintering (i.e., TAMI made of TiO2+ZrO2) and anodic oxidation process (i.e., AAO made of Al2O3) were employed for bench-scale tests. Precoagulation was shown to play an important role in both enhancing membrane filterability and natural organic matter (NOM) removal efficacy for treating a highorganic surface water. The most critical factors were found to be pH and coagulant dosage with the highest efficiency resulting under low pH and high coagulant dose. Due to the ozone-resistance nature of the ceramic membranes, preozonation allowed the ceramic membranes to be operated at higher flux, especially leading to significant flux improvement when treating seawater in the presence of calcium and magnesium. 4 Dissolved ozone in contact with the TAMI ceramic membrane surface accelerated the formation of hydroxyl (˙OH) radicals in WW effluent treatment. Flux restoration of both ceramic membranes, fouled with seawater and WW effluent, was efficiently achieved by high backwash (BW) pressure and ozone in chemically enhanced backwashing (CEB). Ceramic membranes exhibited a pH-dependent permeate flux while filtering WW effluent, showing reduced fouling with increased pH. On the other hand, for filtering seawater, differences in permeate flux between the two membranes was

  11. Co-Sintering behaviour of zirconia-ferritic steel composites

    Directory of Open Access Journals (Sweden)

    Alexander Michaelis

    2016-08-01

    Full Text Available The combination of metallic and ceramic materials allows the combination of positive properties of both and can be applied in various industrial fields. At the moment, the deployment of these composites faces difficult and complex manufacturing. One attempt, which offers a short process route and a high degree of flexibility regarding design is a combined shaping (co-shaping with a combined sintering (co-sintering. The article will show co-sintering results of different metal-ceramic symmetric and asymmetric multi-layered tapes, consisting of yttria stabilized zirconia combined with a ferritic iron chromium steel. Focus is on the densification and co-sintering behaviour of ceramic layers depending on the sintering behaviour of metallic layers. Co-sintered composites were characterized by field emission scanning electron microscopy, x-ray diffraction measurements and in terms of adhesive tensile strength.

  12. Reactive Sintering of Bimodal WC-Co Hardmetals

    OpenAIRE

    Marek Tarraste; Kristjan Juhani; Jüri Pirso; Mart Viljus

    2015-01-01

    Bimodal WC-Co hardmetals were produced using novel technology - reactive sintering. Milled and activated tungsten and graphite powders were mixed with commercial coarse grained WC-Co powder and then sintered. The microstructure of produced materials was free of defects and consisted of evenly distributed coarse and fine tungsten carbide grains in cobalt binder. The microstructure, hardness and fracture toughness of reactive sintered bimodal WC-Co hardmetals is exhibited. Developed bimodal har...

  13. Coagulation defects in experimental hepatic injury in the dog.

    Science.gov (United States)

    Osbaldiston, G W; Hoffman, M W

    1971-04-01

    Alteration in activity of blood coagulation factors in dogs with acute hepatic injury caused by oral carbon tetrachloride dosing was studied. Coagulation Factors II, VII and IX were dramatically reduced within 48 hours but recovered to normal in the next five days. Because surgery is rarely performed on dogs with hepatic necrosis, the use of fresh whole blood tranfusion to improve the coagulation defect in hepatic injury was also studied. Transfusion was found to have only a temporary beneficial effect.

  14. In Vitro Assessment of Nanoparticle Effects on Blood Coagulation.

    Science.gov (United States)

    Potter, Timothy M; Rodriguez, Jamie C; Neun, Barry W; Ilinskaya, Anna N; Cedrone, Edward; Dobrovolskaia, Marina A

    2018-01-01

    Blood clotting is a complex process which involves both cellular and biochemical components. The key cellular players in the blood clotting process are thrombocytes or platelets. Other cells, including leukocytes and endothelial cells, contribute to clotting by expressing the so-called pro-coagulant activity (PCA) complex on their surface. The biochemical component of blood clotting is represented by the plasma coagulation cascade, which includes plasma proteins also known as coagulation factors. The coordinated interaction between platelets, leukocytes, endothelial cells, and plasma coagulation factors is necessary for maintaining hemostasis and for preventing excessive bleeding. Undesirable activation of all or some of these components may lead to pathological blood coagulation and life-threatening conditions such as consumptive coagulopathy or disseminated intravascular coagulation (DIC). In contrast, unintended inhibition of the coagulation pathways may lead to hemorrhage. Thrombogenicity is the property of a test material to induce blood coagulation by affecting one or more elements of the clotting process. Anticoagulant activity refers to the property of a test material to inhibit coagulation. The tendency to cause platelet aggregation, perturb plasma coagulation, and induce leukocyte PCA can serve as an in vitro measure of a nanomaterial's likelihood to be pro- or anticoagulant in vivo. This chapter describes three procedures for in vitro analyses of platelet aggregation, plasma coagulation time, and activation of leukocyte PCA. Platelet aggregation and plasma coagulation procedures have been described earlier. The revision here includes updated details about nanoparticle sample preparation, selection of nanoparticle concentration for the in vitro study, and updated details about assay controls. The chapter is expanded to describe a method for the leukocyte PCA analysis and case studies demonstrating the performance of these in vitro assays.

  15. Coagulation and flocculation of dissolved organic substances with organic polymers

    OpenAIRE

    Kvinnesland, Thomas

    2002-01-01

    Coagulation of natural organic matter (NOM) in water is a well-established process, enabling or enhancing the removal of these substances by different particle separation processes. The dominating coagulating agents used are, however, inorganic salts of iron (Fe3+) and aluminium (Al3+). The primary use of organic polymers is as flocculating agents for already coagulated aggregates. However, in recent years the use of cationic organic polymers have received increasing attent...

  16. Effects of forming temperature and sintering rate to the final properties of FeCuAl powder compacts formed through uniaxial die compaction process

    Science.gov (United States)

    Rahman, M. M.; Ismail, M. A.; Sopyan, I.; Rahman, H. Y.

    2018-01-01

    This paper presents the outcomes of an experimental investigation on the effects of forming temperature and sintering schedule to the final characteristics of FeCuAl powder mass formed at different temperature and sintered at different schedule. A lab-scale uni-axial die compaction rig was designed and fabricated which enabled the compaction of powder mass at room temperature as well as elevated temperature. Iron (Fe) powder ASC 100.29 was mechanically mixed with other elemental powders, namely copper (Cu), and aluminum (Al) for 60 minutes and compacted at three different temperature, i.e., 30°C, 150°C, and 200°C by applying 425 MPa of simultaneous downward and upward axial loading to generate green compacts. The as-pressed samples were inspected visually and the defect-free green compacts were subsequently sintered in an argon gas fired furnace at 800°C for 60 min at three different heating/cooling rates, i.e., 5, 10, and 15°C/min, respectively. The sintered samples were then characterised for their physical, electrical, and mechanical properties. The microstructures of the sintered samples were also analysed. The results revealed that a forming temperature of 150°C and a sintering rate of 10°C/min could produce a product with better characteristics.

  17. Sintering of Lead-Free Piezoelectric Sodium Potassium Niobate Ceramics

    Directory of Open Access Journals (Sweden)

    Barbara Malič

    2015-12-01

    Full Text Available The potassium sodium niobate, K0.5Na0.5NbO3, solid solution (KNN is considered as one of the most promising, environment-friendly, lead-free candidates to replace highly efficient, lead-based piezoelectrics. Since the first reports of KNN, it has been recognized that obtaining phase-pure materials with a high density and a uniform, fine-grained microstructure is a major challenge. For this reason the present paper reviews the different methods for consolidating KNN ceramics. The difficulties involved in the solid-state synthesis of KNN powder, i.e., obtaining phase purity, the stoichiometry of the perovskite phase, and the chemical homogeneity, are discussed. The solid-state sintering of stoichiometric KNN is characterized by poor densification and an extremely narrow sintering-temperature range, which is close to the solidus temperature. A study of the initial sintering stage revealed that coarsening of the microstructure without densification contributes to a reduction of the driving force for sintering. The influences of the (K + Na/Nb molar ratio, the presence of a liquid phase, chemical modifications (doping, complex solid solutions and different atmospheres (i.e., defect chemistry on the sintering are discussed. Special sintering techniques, such as pressure-assisted sintering and spark-plasma sintering, can be effective methods for enhancing the density of KNN ceramics. The sintering behavior of KNN is compared to that of a representative piezoelectric lead zirconate titanate (PZT.

  18. Sintering of Lead-Free Piezoelectric Sodium Potassium Niobate Ceramics

    Science.gov (United States)

    Malič, Barbara; Koruza, Jurij; Hreščak, Jitka; Bernard, Janez; Wang, Ke; Fisher, John G.; Benčan, Andreja

    2015-01-01

    The potassium sodium niobate, K0.5Na0.5NbO3, solid solution (KNN) is considered as one of the most promising, environment-friendly, lead-free candidates to replace highly efficient, lead-based piezoelectrics. Since the first reports of KNN, it has been recognized that obtaining phase-pure materials with a high density and a uniform, fine-grained microstructure is a major challenge. For this reason the present paper reviews the different methods for consolidating KNN ceramics. The difficulties involved in the solid-state synthesis of KNN powder, i.e., obtaining phase purity, the stoichiometry of the perovskite phase, and the chemical homogeneity, are discussed. The solid-state sintering of stoichiometric KNN is characterized by poor densification and an extremely narrow sintering-temperature range, which is close to the solidus temperature. A study of the initial sintering stage revealed that coarsening of the microstructure without densification contributes to a reduction of the driving force for sintering. The influences of the (K + Na)/Nb molar ratio, the presence of a liquid phase, chemical modifications (doping, complex solid solutions) and different atmospheres (i.e., defect chemistry) on the sintering are discussed. Special sintering techniques, such as pressure-assisted sintering and spark-plasma sintering, can be effective methods for enhancing the density of KNN ceramics. The sintering behavior of KNN is compared to that of a representative piezoelectric lead zirconate titanate (PZT). PMID:28793702

  19. The electric conductivity of some forms of sintered synthetic zeolites

    International Nuclear Information System (INIS)

    Susic, M.; Petrovic, V.; Ristic, M.; Petranovic, N.

    1978-01-01

    Some forms of synthetic zeolites were sintered and their electric conductivity was measured. The conductivity was observed in correlation with the conductivity of non-sintered pressed samples. Also the change in microstructural constituents in the course of the process of sintering was observed with an optical microscope. It has been found that there is a considerable change in conductivity due to sintering as well as a change in the activation energy for conduction. Also the porosity is noticeably changed. A marked affect of the nature of counter ions on the electric conductivity is shown

  20. Sintering, microstructural and dilatometric studies of combustion synthesized Synroc phases

    International Nuclear Information System (INIS)

    Muthuraman, M.; Patil, K.C.; Senbagaraman, S.; Umarji, A.M.

    1996-01-01

    Sintering, microstructure, and linear thermal expansion properties of Synroc-B and constituent phases, viz. perovskite CaTiO 3 , zirconolite ZrTi 2 O 7 , hollandite (ideal formula BaAl2Ti 6 O 16 ) have been investigated. Synroc-B powder when pelletized and sintered at 1250 C for 2 h achieved >95% theoretical density. Sintered Synroc-B has a linear thermal expansion coefficient α of 8.72 x 10 -6 K -1 and Vicker's microhardness 9.88 GPa. The linear thermal expansion curves did not show any hysteresis indicating the absence of microcracking in the sintered bodies

  1. Rapid laser sintering of metal nano-particles inks.

    Science.gov (United States)

    Ermak, Oleg; Zenou, Michael; Toker, Gil Bernstein; Ankri, Jonathan; Shacham-Diamand, Yosi; Kotler, Zvi

    2016-09-23

    Fast sintering is of importance in additive metallization processes and especially on sensitive substrates. This work explores the mechanisms which set limits to the laser sintering rate of metal nano-particle inks. A comparison of sintering behavior of three different ink compositions with laser exposure times from micro-seconds to seconds reveals the dominant factor to be the organic content (OC) in the ink. With a low OC silver ink, of 2% only, sintering time falls below 100 μs with resistivity <×4 bulk silver. Still shorter exposure times result in line delamination and deformation with a similar outcome when the OC is increased.

  2. [Evaluation of coagulation disorders with thrombelastography in patients with sepsis].

    Science.gov (United States)

    Zhong, Shengjian; Zhang, Chunbao; Hu, Juntao; Tang, Zhanhong

    2016-02-01

    To compare the results of thrombelastography (TEG) and the conventional coagulability test in patients with sepsis, and to discuss the value of TEG in monitoring blood coagulation dysfunction in patients with sepsis. The clinical data of 92 adult patients with sepsis admitted to Department of Critical Care Medicine of the First Affiliated Hospital of Guangxi Medical University were retrospectively analyzed. The patients were divided into sequential organ failure assessment (SOFA) score ≥ 12 group (n = 47) and SOFA coagulation function served as control group. The venous blood was collected for conventional blood coagulation test and routine examination of blood, D-dimer, procalcitonin (PCT), and TEG, and the differences were compared among three groups. Correlations between SOFA and various indexes of patients with sepsis were analyzed by Spearman rank correlation method. As shown in the results of the conventional blood coagulation test, D-dimer was gradually increased with the aggravation of the disease, the values in non-sepsis, SOFA coagulation test might not respond quickly to the change in coagulation status of sepsis patients. As shown in the results of TEG, the values of reaction time (R value) and kinetics time (K value) in SOFA 0.05; K value (minutes): 4.2 (3.4, 7.1) vs. 1.5 (1.3, 1.8), P coagulation index (CI) in SOFA coagulation in patients with sepsis, and distinguish the hypercoagulable and hypocoagulable state. TEG may be a valuable tool to evaluate degree and risk of sepsis objectively.

  3. Interpretation of Frenkel’s theory of sintering considering evolution of activated pores: III. Determination of equilibrium sintering time

    Directory of Open Access Journals (Sweden)

    Yu C.L.

    2015-01-01

    Full Text Available In this article, the Frenkel’s theory of liquid-phase sintering was interpreted regarding pores as the activated volume. The mathematical model established by Nikolić et al. was used to infer the equilibrium sintering time at varied sintering temperatures during the isothermal sintering of codierite glass by Giess et al. Through the calculation, the equilibrium time at 800ºC, 820ºC, 840ºC and 860ºC is inferred to be 7014.42mins, 1569.65mins, 368.92mins and 114.61mins, respectively. The equilibrium time decreases as the temperature increases. And the theoretical value is in good accordance with the experimental results. Thus, the model established by Nikolić et al. can be applied successfully to predict the equilibrium sintering time of the cordierite glass at varied temperatures during isothermal sintering.

  4. The Coagulation Profile of End-Stage Liver Disease and Considerations for Intraoperative Management.

    Science.gov (United States)

    Forkin, Katherine T; Colquhoun, Douglas A; Nemergut, Edward C; Huffmyer, Julie L

    2018-01-01

    The coagulopathy of end-stage liver disease results from a complex derangement in both anticoagulant and procoagulant processes. With even minor insults, cirrhotic patients experience either inappropriate bleeding or clotting, or even both simultaneously. The various phases of liver transplantation along with fluid and blood product administration may contribute to additional disturbances in coagulation. Thus, anesthetic management of patients undergoing liver transplantation to improve hemostasis and avoid inappropriate thrombosis in the perioperative environment can be challenging. To add to this challenge, traditional laboratory tests of coagulation are difficult to interpret in patients with end-stage liver disease. Viscoelastic coagulation tests such as thromboelastography (Haemonetics Corporation, Braintree, MA) and rotational thromboelastometry (TEM International, Munich, Germany) have helped to reduce transfusion of allogeneic blood products, especially fresh frozen plasma, but have also lead to the increased use of fibrinogen-containing products. In general, advancements in surgical techniques and anesthetic management have led to significant reduction in blood transfusion requirements during liver transplantation. Targeted transfusion protocols and pharmacologic prevention of fibrinolysis may further aid in the management of the complex coagulopathy of end-stage liver disease.

  5. Rapid evaluation of fibrinogen levels using the CG02N whole blood coagulation analyzer.

    Science.gov (United States)

    Hayakawa, Mineji; Gando, Satoshi; Ono, Yuichi; Mizugaki, Asumi; Katabami, Kenichi; Maekawa, Kunihiko; Miyamoto, Daisuke; Wada, Takeshi; Yanagida, Yuichiro; Sawamura, Atsushi

    2015-04-01

    Rapid evaluation of fibrinogen (Fbg) levels is essential for maintaining homeostasis in patients with massive bleeding during severe trauma and major surgery. This study evaluated the accuracy of fibrinogen levels measured by the CG02N whole blood coagulation analyzer (A&T Corporation, Kanagawa, Japan) using heparinized blood drawn for blood gas analysis (whole blood-Fbg). A total of 100 matched pairs of heparinized blood samples and citrated blood samples were simultaneously collected from patients in the intensive care unit. Whole blood-Fbg results were compared with those of citrated plasma (standard-Fbg). The whole blood coagulation analyzer measured fibrinogen levels within 2 minutes. Strong correlations between standard-Fbg and whole blood-Fbg were observed (ρ = 0.91, p coagulation analyzer can rapidly measure fibrinogen levels in heparinized blood and could be useful in critical care settings where excessive bleeding is a concern. Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

  6. [Comparison of thromboelastography and routine coagulation tests for evaluation of blood coagulation function in patients].

    Science.gov (United States)

    Chen, Guan-Yi; Ou Yang, Xi-Lin; Wu, Jing-Hui; Wang, Li-Hua; Yang, Jin-Hua; Gu, Li-Nan; Lu, Zhu-Jie; Zhao, Xiao-Zi

    2015-04-01

    To investigate the correlation and consistency between thromboelastography(TEG) and routine coagulation tests, and to evaluate the value of the two methods in determining the blood coagulation of patients. The TEG, routine coagulation tests and platelet counts of 182 patients from the Intensive Care Unit(ICU) and Department of Gastroenterology in our hospital from January to September 2014 were performed and analyzed retrospectively for their correlation, Kappa identity test analysis and chi-square test, and the diagnostic sensitivity and specificity of both methods in the patients with bleeding were evaluated. The TEG R time and PT, R time and APTT showed a linear dependence (P0.05) and 0.061 (P>0.05), respectively. The chi-square test values of the TEG R time with PT and APTT were 35.309 (Pcoagulation tests, but the consistency is weak. Moreover, the diagnostic sensitivity of two methods in the patients with bleeding is low. It was concluded that the TEG cannot replace the conventional coagulation tests, and the preferable method remains uncertain which could reflect the risk of bleeding.

  7. Effects of nucleotides and nucleosides on coagulation

    DEFF Research Database (Denmark)

    Bune, Laurids; Thaning, Pia; Johansson, Pär I

    2010-01-01

    Nucleotides, including ADP, ATP and uridine triphosphate (UTP), are discharged profusely in the circulation during many pathological conditions including sepsis. Sepsis can cause hypotension and systemic activation of the coagulation and fibrinolytic systems in humans, which may cause disseminated...... of adenosine, ADP, ATP, UTP or nitric oxide until mean arterial pressure was reduced to approximately 40% of baseline simulating sepsis-induced hypotension. The effect of the infusions on the haemostatic system was evaluated by TEG, and endothelial release of tissue plasminogen activator and plasminogen...... activator inhibitor-1 was measured. In contrast to the other infused substrates, ADP caused a reduction in maximum amplitude (71.4 to 64.2; P

  8. Residual stresses in a co-sintered SOC half-cell during post-sintering cooling

    DEFF Research Database (Denmark)

    Charlas, Benoit; Chatzichristodoulou, Christodoulos; Brodersen, Karen

    2014-01-01

    Due to the thermal expansion mismatch between the layers of a Solid Oxide Cell, residual stresses (thermal stresses) develop during the cooling after sintering. Residual stresses can induce cell curvature for asymmetric cells but more importantly they also result in more fragile cells. Depending...

  9. Powder densification maps in Selective Laser Sintering

    International Nuclear Information System (INIS)

    Bourell, D.; Wohlert, M.; Harlan, N.; Beaman, J.; Das, S.

    2002-01-01

    Selective Laser Sintering (SLS) is a manufacturing process in which a part is produced without the need for part-specific tooling. It competes effectively with other manufacturing processes when part geometry is complex and the production run is not large. Traditionally, this was limited to prototype production, although tooling applications are now appearing. This paper describes several applications of powder densification maps to advance solutions in direct SLS of metallic and ceramic powders. Time-dependent plasticity issues arise in pre-processing of powder to make it suitable for SLS and in post-processing of SLS parts to obtain desired density. (Abstract Copyright [2002], Wiley Periodicals, Inc.)

  10. Computer Modeling of Direct Metal Laser Sintering

    Science.gov (United States)

    Cross, Matthew

    2014-01-01

    A computational approach to modeling direct metal laser sintering (DMLS) additive manufacturing process is presented. The primary application of the model is for determining the temperature history of parts fabricated using DMLS to evaluate residual stresses found in finished pieces and to assess manufacturing process strategies to reduce part slumping. The model utilizes MSC SINDA as a heat transfer solver with imbedded FORTRAN computer code to direct laser motion, apply laser heating as a boundary condition, and simulate the addition of metal powder layers during part fabrication. Model results are compared to available data collected during in situ DMLS part manufacture.

  11. Selective laser sintering in biomedical engineering.

    Science.gov (United States)

    Mazzoli, Alida

    2013-03-01

    Selective laser sintering (SLS) is a solid freeform fabrication technique, developed by Carl Deckard for his master's thesis at the University of Texas, patented in 1989. SLS manufacturing is a technique that produces physical models through a selective solidification of a variety of fine powders. SLS technology is getting a great amount of attention in the clinical field. In this paper the characteristics features of SLS and the materials that have been developed for are reviewed together with a discussion on the principles of the above-mentioned manufacturing technique. The applications of SLS in tissue engineering, and at-large in the biomedical field, are reviewed and discussed.

  12. SEM hot stage sintering of UO2

    International Nuclear Information System (INIS)

    Miller, D.J.

    1976-06-01

    The sintering of hyperstoichiometric uranium dioxide powder compacts, in the hot stage of a scanning electron microscope, was continuously monitored using 16 mm time lapse movies. From alumina microspheres placed on the surface of the compacts, shrinkage measurements were obtained. Converting shrinkage measurements into densification profiles indicates that a maximum densification rate is reached at a critical density, independent of the constant heating rates. At temperatures above 1350 0 C, the movement of the reference microspheres made shrinkage measurements impossible. It is believed the evolution of UO 3 gas from hyperstoichiometric UO 2 is the cause of this limitation

  13. A cartridge based sensor array platform for multiple coagulation measurements from plasma.

    Science.gov (United States)

    Cakmak, O; Ermek, E; Kilinc, N; Bulut, S; Baris, I; Kavakli, I H; Yaralioglu, G G; Urey, Hakan

    2015-01-07

    This paper proposes a MEMS-based sensor array enabling multiple clot-time tests for plasma in one disposable microfluidic cartridge. The versatile LoC (Lab-on-Chip) platform technology is demonstrated here for real-time coagulation tests (activated Partial Thromboplastin Time (aPTT) and Prothrombin Time (PT)). The system has a reader unit and a disposable cartridge. The reader has no electrical connections to the cartridge. This enables simple and low-cost cartridge designs and avoids reliability problems associated with electrical connections. The cartridge consists of microfluidic channels and MEMS microcantilevers placed in each channel. The microcantilevers are made of electroplated nickel. They are actuated remotely using an external electro-coil and the read-out is also conducted remotely using a laser. The phase difference between the cantilever oscillation and the coil drive is monitored in real time. During coagulation, the viscosity of the blood plasma increases resulting in a change in the phase read-out. The proposed assay was tested on human and control plasma samples for PT and aPTT measurements. PT and aPTT measurements from control plasma samples are comparable with the manufacturer's datasheet and the commercial reference device. The measurement system has an overall 7.28% and 6.33% CV for PT and aPTT, respectively. For further implementation, the microfluidic channels of the cartridge were functionalized for PT and aPTT tests by drying specific reagents in each channel. Since simultaneous PT and aPTT measurements are needed in order to properly evaluate the coagulation system, one of the most prominent features of the proposed assay is enabling parallel measurement of different coagulation parameters. Additionally, the design of the cartridge and the read-out system as well as the obtained reproducible results with 10 μl of the plasma samples suggest an opportunity for a possible point-of-care application.

  14. Transurethral laser coagulation of the prostate

    Science.gov (United States)

    Mattioli, Stefano; Cremona, M.

    1994-02-01

    We describe the laser coagulation of the prostate using a conventional bare fiber inserted in a modified Albarran bridge which presents at the distal tip, a newly designed gold-plated reflector, connected by a deflecting mechanism. This allows delivery of laser energy (40 - 80 W) by direct reflection of the Nd:YAG laser light, an angularity more accentuated compared with other systems. Transurethral laser coagulation was performed on 25 patients for prostatic obstruction benign prostatic hyperplasia (BPH) and 6 selected patients for carcinoma of the prostate (December 91 - January 93). Patient selection (BPH) was limited to median lobe (range 50 - 55 years), small prostates, older and high-risk patients. Successful results were noted in 20 of the 25 cases of BPH group (80%). A significant reduction of obstructive symptoms was associated with an increase of maximal a medium flow rates. In the early prostate cancer group, the method has resulted in 3 patients with no evidence of disease, despite repeated biopsy, biochemical, and clinical investigations (PSA range level > 20 ng/ml to < 0.5 ng/ml at one year). The results are encouraging at this stage.

  15. Natural organic matters removal efficiency by coagulation

    Science.gov (United States)

    Sapingi, Mohd Sharizal Mohd; Pishal, Munirah; Murshed, Mohamad Fared

    2017-10-01

    The presence of Natural Organic Matter (NOM) in surface water results in unwanted characteristics in terms of color, odor, and taste. NOM content reaction with free chlorine in treated water lowers the water quality further. Chlorine is added for disinfection and produces undesirable disinfection by-products (DPBs). DBPs in drinking water are carcinogenic to consumers and may promote cancerous cell development in the human body. This study was performed to compare the coagulant efficiency of aluminum sulfate (Alum) and ferric chloride (FeCl3) on NOM removal (as in UV254 absorbance) and turbidity removal under three pH conditions (pH 6, pH 7, and sample actual pH). The three sampling points for these studies were Jalan Baru River, Kerian River, and Redac Pond. Additional sampling points, such as Lubuk Buntar and a tubewell located in the Civil Engineering School, were included to observe differences in characteristics. DOC, UV absorbance, and full wavelength were tested, after which samples treated with alum were also tested to further analyze the NOM content. Based on UV254 absorbance and DOC data, specific UV value was calculated to obtain vital synopsis of the characteristics of NOM content, as well as coagulation efficiency.

  16. Coagulation studies in patients with orthopedic trauma

    Directory of Open Access Journals (Sweden)

    Rangarajan Kanchana

    2010-01-01

    Full Text Available Background : Head injury, severe acidosis, hypothermia, massive transfusion and hypoxia often complicate traumatic coagulopathy. First line investigations such as prothrombin time, activated partial thromboplastin time, thrombin time, fibrinogen level, platelet count and D-dimer levels help in the initial assessment of coagulopathy in a trauma victim. Aim : To study the coagulation profile in patients of orthopedic trauma. Settings and Design : Prospective study. Patients and Methods : Patients with head injury, severe acidosis, massive transfusion and severe hypoxia were excluded from the study. Coagulation parameters were evaluated at three intervals, at the time of admission, intra operatively and in the postoperative period. Statistical Analysis : Chi-square test was used for analysis of categorical variables. For comparison between groups, two- way ANOVA was used. Results and Conclusions : Of the 48 patients studied, 38 (80% had normal DIC scores upon admission and only 10 (20% had mild DIC scores at the time of admission. The median Injury Severity Score was 34 and they did not correlate with DIC scores. Fibrinogen levels alone were significantly different, increased progressively (mean pre op, intra op and post op levels 518 ± 31,582 ± 35 and 643 ± 27 respectively; P ≤ 0.02 since the time of admission in these patients. All the other parameters remained unchanged. Further large scale prospective studies would be required to correlate elevated fibrinogen levels with the type of trauma or surgery.

  17. Perioperative coagulation management--fresh frozen plasma.

    Science.gov (United States)

    Kor, Daryl J; Stubbs, James R; Gajic, Ognjen

    2010-03-01

    Clinical studies support the use of perioperative fresh frozen plasma (FFP) in patients who are actively bleeding with multiple coagulation factor deficiencies and for the prevention of dilutional coagulopathy in patients with major trauma and/or massive haemorrhage. In these settings, current FFP dosing recommendations may be inadequate. However, a substantial proportion of FFP is transfused in non-bleeding patients with mild elevations in coagulation screening tests. This practice is not supported by the literature, is unlikely to be of benefit and unnecessarily exposes patients to the risks of FFP. The role of FFP in reversing the effects of warfarin anticoagulation is dependent on the clinical context and availability of alternative agents. Although FFP is commonly transfused in patients with liver disease, this practice needs broad reconsideration. Adverse effects of FFP include febrile and allergic reactions, transfusion-associated circulatory overload and transfusion-related acute lung injury. The latter is the most serious complication, being less common with the preferential use of non-alloimmunised, male-donor predominant plasma. FP24 and thawed plasma are alternatives to FFP with similar indications for administration. Both provide an opportunity for increasing the safe plasma donor pool. Although prothrombin complex concentrates and factor VIIa may be used as alternatives to FFP in a variety of specific clinical contexts, additional study is needed.

  18. Platelets contain releasable coagulation factor IX antigen.

    Science.gov (United States)

    Romp, K G; Monroe, D M; Hoffman, M

    1993-12-01

    Platelets take up plasma proteins into their alpha granules. Platelet activation releases the alpha granule contents. The goal of this study was to test the hypothesis that human platelets also contain some coagulation factor IX in their alpha granules. Platelets were examined by immunofluorescence microscopy. Activated and unactivated platelets were quick frozen on to slides and dehydrated in situ to preserve optimal morphology. The slides were stained by indirect immunofluorescence for factors V and IX. Unactivated platelets showed coarsely granular staining for factor V and finely granular staining for factor IX. Staining for factor V was diffuse after activation, while staining for factor IX disappeared. Thus, the results support the conclusion that platelets contain factor IX which can be released upon activation. Immunoelectron microscopic studies were conducted to more precisely localize the site of the platelet factor IX. As expected, factor V was primarily localized in the alpha granules of unactivated platelets. By contrast, factor IX was observed both in alpha granules and diffusely in the platelet cytoplasm and membrane-bounded vesicles. After activation, staining for both factors V and IX was primarily in the open canalicular system. The physiological importance of this small amount of factor IX is unknown. However, it may be significant since only a few percent of normal IX levels are required to support haemostasis in the absence of trauma, and platelet factor IX could be released at sites of active coagulation.

  19. Direct metal laser sintering: a digitised metal casting technology.

    Science.gov (United States)

    Venkatesh, K Vijay; Nandini, V Vidyashree

    2013-12-01

    Dental technology is undergoing advancements at a fast pace and technology is being imported from various other fields. One such imported technology is direct metal laser sintering technology for casting metal crowns. This article will discuss the process of laser sintering for making metal crowns and fixed partial dentures with a understanding of their pros and cons.

  20. Monitoring Sintering Burn-Through Point Using Infrared Thermography

    Directory of Open Access Journals (Sweden)

    Francisco G. Bulnes

    2013-08-01

    Full Text Available Sintering is a complex industrial process that applies heat to fine particles of iron ore and other materials to produce sinter, a solidified porous material used in blast furnaces. The sintering process needs to be carefully adjusted, so that the combustion zone reaches the bottom of the material just before the discharge end. This is known as the burnthrough point. Many different parameters need to be finely tuned, including the speed and the quantities of the materials mixed. However, in order to achieve good results, sintering control requires precise feedback to adjust these parameters. This work presents a sensor to monitor the sintering burn-through point based on infrared thermography. The proposed procedure is based on the acquisition of infrared images at the end of the sintering process. At this position, infrared images contain the cross-section temperatures of the mixture. The objective of this work is to process this information to extract relevant features about the sintering process. The proposed procedure is based on four steps: key frame detection, region of interest detection, segmentation and feature extraction. The results indicate that the proposed procedure is very robust and reliable, providing features that can be used effectively to control the sintering process.

  1. Monitoring sintering burn-through point using infrared thermography.

    Science.gov (United States)

    Usamentiaga, Rubén; Molleda, Julio; Garcia, Daniel F; Bulnes, Francisco G

    2013-08-09

    Sintering is a complex industrial process that applies heat to fine particles of iron ore and other materials to produce sinter, a solidified porous material used in blast furnaces. The sintering process needs to be carefully adjusted, so that the combustion zone reaches the bottom of the material just before the discharge end. This is known as the burn-through point. Many different parameters need to be finely tuned, including the speed and the quantities of the materials mixed. However, in order to achieve good results, sintering control requires precise feedback to adjust these parameters. This work presents a sensor to monitor the sintering burn-through point based on infrared thermography. The proposed procedure is based on the acquisition of infrared images at the end of the sintering process. At this position, infrared images contain the cross-section temperatures of the mixture. The objective of this work is to process this information to extract relevant features about the sintering process. The proposed procedure is based on four steps: key frame detection, region of interest detection, segmentation and feature extraction. The results indicate that the proposed procedure is very robust and reliable, providing features that can be used effectively to control the sintering process.

  2. Tool design and materials for electro sinter forging (ESF)

    DEFF Research Database (Denmark)

    Cannella, Emanuele; Nielsen, Chris Valentin

    A near net-shape forming process represents a suitable solution to obtain the final product by avoiding secondary machining processes. In this field, electro sinter forging is capable of accomplishing the advantages of sintering in a reduced amount of time. Classified as a high field mode (HFM...

  3. Effects of Sintering Temperature on the Density And Porosity of ...

    African Journals Online (AJOL)

    Effects of sintering temperature on the density and porosity of sodium chloride preforms for alu- minium foam manufacturing have been investigated. Cold pressed salt preforms were sintered at 30, 760 and 790 and di erent times ranging between 6- 18 hours in a carbolite furnace at a heating rate of 5/minute. The Results of ...

  4. Monitoring Sintering Burn-Through Point Using Infrared Thermography

    Science.gov (United States)

    Usamentiaga, Rubén; Molleda, Julio; Garcia, Daniel F.; Bulnes, Francisco G.

    2013-01-01

    Sintering is a complex industrial process that applies heat to fine particles of iron ore and other materials to produce sinter, a solidified porous material used in blast furnaces. The sintering process needs to be carefully adjusted, so that the combustion zone reaches the bottom of the material just before the discharge end. This is known as the burn-through point. Many different parameters need to be finely tuned, including the speed and the quantities of the materials mixed. However, in order to achieve good results, sintering control requires precise feedback to adjust these parameters. This work presents a sensor to monitor the sintering burn-through point based on infrared thermography. The proposed procedure is based on the acquisition of infrared images at the end of the sintering process. At this position, infrared images contain the cross-section temperatures of the mixture. The objective of this work is to process this information to extract relevant features about the sintering process. The proposed procedure is based on four steps: key frame detection, region of interest detection, segmentation and feature extraction. The results indicate that the proposed procedure is very robust and reliable, providing features that can be used effectively to control the sintering process. PMID:23939585

  5. Effect of sintering temperature on structural and electrical properties ...

    Indian Academy of Sciences (India)

    TECS

    vity measurement. The crystallinity and surface morphology of the samples improved with sintering tempera- ture. Further, the electrical conductivity measurement indicated that the conduction mechanism is mainly ionic. The conductivity of samples sintered at 1673 K and 1773 K at 800°C are of the order of 0⋅1 S-cm. –1.

  6. The sintering behavior of close-packed spheres

    DEFF Research Database (Denmark)

    Bjørk, Rasmus; Tikare, V.; Frandsen, Henrik Lund

    2012-01-01

    The sintering behavior of close-packed spheres is investigated using a numerical model. The investigated systems are the body-centered cubic (bcc), face-centered cubic (fcc) and hexagonal close-packed spheres (hcp). The sintering behavior is found to be ideal, with no grain growth until full dens...

  7. Field assisted hot pressing of sintering Inconel 718 MIM samples

    Science.gov (United States)

    Dugauguez, Olivier; Torralba, Jose Manuel; Barriere, Thierry; Gelin, Jean-Claude

    2016-10-01

    In this investigation on samples obtained by Metal Injection Molding (MIM), the conventional way of sintering in a furnace will be compared to Field Assisted Hot pressing (FAHP) sintering. The difficulty of this method is to be able to control the shrinkage of the sample and so its shape. It has yet not been investigated with a super alloy powder and so, the effects of a high sintering rate. By accelerating the sintering kinetics, the thermal behavior may be modified. Hence, the behavior of the Inconel 718 sintered by FAHP has been investigated. The sintered samples were all injected from a feedstock composed of a fine particle Inconel powder and a binder principally composed of Cellulose Acetate Butyrate CAB and Poly-Ethylene Glycol PEG. The effects of the two methods on the microstructure and the mechanical properties are then compared. There was no difference in distribution of pores between the conventional sintering and the FAHP sintering but a finer grain size showed better hardness.

  8. Sintering of Multilayered Porous Structures: Part I-Constitutive Models

    DEFF Research Database (Denmark)

    Olevsky, Eugene; Tadesse Molla, Tesfaye; Frandsen, Henrik Lund

    2013-01-01

    Theoretical analyses of shrinkage and distortion kinetics during sintering of bilayered porous structures are carried out. The developed modeling framework is based on the continuum theory of sintering; it enables the direct assessment of the cofiring process outcomes and of the impact of process...

  9. Microstructure and properties of sintered mullite developed from ...

    Indian Academy of Sciences (India)

    Dense mullite aggregates with 72% Al2O3 have been synthesized by reaction sintering of two varieties of Indian bauxite and silica sol. The bauxites used are of inferior grade with different levels of accessory impurities such as Fe2O3, TiO2, CaO. The phase and microstructure development of sintered samples were ...

  10. Sintering, camber development of layer composites and a new ...

    Indian Academy of Sciences (India)

    NiZnCu hexagonal ferrite (abbreviated as ZT/NZC) composite samples were prepared successfully by using restricted shrinkage sintering process (RSS) (Liu et al 2009a, b). But the electromagnetic performance degra- dation of co-sintered layer ...

  11. Comparison of the Performance of Corn Starch Coagulant Aid Accompany with Alum, Polyaluminum Chloride and Ferric Chloride Coagulants in Turbidity Removal from Water

    OpenAIRE

    Leila Mosleh; Seyed Hossein Seyed Hossein; Reza Deihim Fard; Korous Khoshbakht; Afsane Shahbazi

    2014-01-01

    Background: The most important process in water treatment plant is coagulation and flocculation. Regular chemical coagulant which used in Iran are aluminum sulfate (Alum) and ferric chloride. Chemical coagulants have hazardous effect on human health and their cost is high for developing country. The purpose of this study was to evaluate the comparison of chemical coagulants accompany with corn starch as a coagulant aid, for the turbidity removal from water. Methods: This study was accompl...

  12. Critical assessment of chitosan as coagulant to remove cyanobacteria

    NARCIS (Netherlands)

    Lurling, Miguel; Noyma, Natalia Pessoa; Magalhães, de Leonardo; Miranda, Marcela; Mucci, Maíra; Oosterhout, van F.; Huszar, Vera L.M.; Marinho, Marcelo Manzi

    2017-01-01

    Removal of cyanobacteria from the water column using a coagulant and a ballast compound is a promising technique to mitigate nuisance. As coagulant the organic, biodegradable polymer chitosan has been promoted. Results in this study show that elevated pH, as may be common during cyanobacterial

  13. Characteristics of particle coagulation in an underground parking lot.

    Science.gov (United States)

    Zhao, Yu; Kato, Shinsuke; Zhao, Jianing

    2015-12-01

    Particles in vehicle exhaust plumes in underground parking lots have adverse health effects due to the enclosed environment in which they are released and the temperature difference between the tailpipe and ambient environment; at the same time, particle coagulation might be obvious near the tailpipe in an underground parking lot. In the present study, airflow and temperature fields were calculated using the Realizable k-ε model, and the Eulerian particle transport model was selected in the numerical simulation of particle concentration dispersion. Polydisperse thermal coagulation due to Brownian collisions was employed to calculate the particle coagulation. The results show that particle coagulation rate and half-time were significant within 1 m from the tailpipe. The variations in the particle coagulation rate and half-time were similar, but their directions were opposite. Air exhaust time was nearly four times longer than averaged half-time and 40 times longer than minimum half-time. The peak particle diameter increased approximately 1.43 times due to coagulation. A double particle concentration at the tailpipe caused the fourfold rise in the particle coagulation rate in the distance ranging less than 1 m from the tailpipe. An increase in exhaust velocity at the tailpipe could shorten the obvious range of particle coagulation along the centerline of the tailpipe from 1 to 0.8 m in the study.

  14. Toxicity assessment of natural and chemical coagulants using brine ...

    African Journals Online (AJOL)

    Coagulants used in preparing soft cheese or 'Wara' or 'Tofu', and in portable water treatment needed to be assessed preliminarily for toxicity and a simple bench top bioassay, brine shrimp lethality assay, is suitable for such preliminary investigation. Thirteen extracts obtained from seven coagulants, comprising five plants ...

  15. Effects of different coagulants on the physico-chemical, microbial ...

    African Journals Online (AJOL)

    Similarly, coagulants used significantly affected the water absorption capacity, oil absorption capacity, foam capacity and gelation capacity. However, the bulk density was not significantly (p ≥ 0.05) affected. Steep water coagulated cheese had the highest total plate count. The result for sensory properties shows that, lime ...

  16. Coagulation chemistries for silica removal from cooling tower water.

    Energy Technology Data Exchange (ETDEWEB)

    Nyman, May Devan; Altman, Susan Jeanne; Stewart, Tom

    2010-02-01

    The formation of silica scale is a problem for thermoelectric power generating facilities, and this study investigated the potential for removal of silica by means of chemical coagulation from source water before it is subjected to mineral concentration in cooling towers. In Phase I, a screening of many typical as well as novel coagulants was carried out using concentrated cooling tower water, with and without flocculation aids, at concentrations typical for water purification with limited results. In Phase II, it was decided that treatment of source or make up water was more appropriate, and that higher dosing with coagulants delivered promising results. In fact, the less exotic coagulants proved to be more efficacious for reasons not yet fully determined. Some analysis was made of the molecular nature of the precipitated floc, which may aid in process improvements. In Phase III, more detailed study of process conditions for aluminum chloride coagulation was undertaken. Lime-soda water softening and the precipitation of magnesium hydroxide were shown to be too limited in terms of effectiveness, speed, and energy consumption to be considered further for the present application. In Phase IV, sodium aluminate emerged as an effective coagulant for silica, and the most attractive of those tested to date because of its availability, ease of use, and low requirement for additional chemicals. Some process optimization was performed for coagulant concentration and operational pH. It is concluded that silica coagulation with simple aluminum-based agents is effective, simple, and compatible with other industrial processes.

  17. Evaluation of Moringa oleifera seed as coagulation aid for treatment ...

    African Journals Online (AJOL)

    Laboratory tests were carried out to evaluate the potentials of Moringa oleifera seed powder as a coagulation aid for removal of suspended particles in fish culture effluent. The standard jar test was used to investigate the dosage and mixing intensity required to optimize the use of the coagulant in removing of suspended ...

  18. The Study of Hemolysis Effects on Coagulation Parameters

    African Journals Online (AJOL)

    In coagulation assays rejection of hemolyzed samples is ... Background: Rejecting hemolyzed specimens received for coagulation studies is advised ... with the first group. The approval from ethics committee was taken for drawing blood samples from volunteers. Statistical evaluation. GraphPad Prism 5 was the software ...

  19. Genetic parameters for milk coagulation properties in Estonian Holstein cows.

    NARCIS (Netherlands)

    Vallas, M.; Bovenhuis, H.; Kaart, T.; Parna, K.; Kiiman, H.

    2010-01-01

    The objective of this study was to estimate heritabilities and repeatabilities for milk coagulation traits [milk coagulation time (RCT) and curd firmness (E30)] and genetic and phenotypic correlations between milk yield and composition traits (milk fat percentage and protein percentage, urea,

  20. Effects of Puff-Adder Venom on Coagulation, Fibrinolysis and ...

    African Journals Online (AJOL)

    The in vitro and in vivo haematological effects of puffadder (Bitis arietans) venom in the baboon (Papio ursinus) with regard to its effect on coagulation, fibrinolysis and platelet aggregation were studied. There is a delay in the intrinsic coagulation mechanism with fibrinolysis and in vitro fibrinogenolysis. Normal human ...

  1. The relationship between inflammation and the coagulation system

    NARCIS (Netherlands)

    Choi, Goda; Schultz, Marcus J.; Levi, Marcel; van der Poll, Tom

    2006-01-01

    Inflammation and coagulation play pivotal roles in host defence. As phylogenetically old responses, there is extensive cross-talk between inflammation and coagulation in enabling an adequate immune response against potentially injurious stimuli. Immune cells are important in the initiation of

  2. Influence of blood flow on the coagulation cascade

    DEFF Research Database (Denmark)

    The influence of diffusion and convetive flows on the blood coagulation cascade is investigated for a controlled perfusion experiment. We present a cartoon model and reaction schemes for parts of the coagulation cascade with sunsequent set up of a mathematical model in two space dimensions plus one...

  3. Allosteric activation of coagulation factor VIIa visualized by hydrogen exchange

    DEFF Research Database (Denmark)

    Rand, Kasper Dyrberg; Jørgensen, Thomas; Olsen, Ole H

    2006-01-01

    Coagulation factor VIIa (FVIIa) is a serine protease that, after binding to tissue factor (TF), plays a pivotal role in the initiation of blood coagulation. We used hydrogen exchange monitored by mass spectrometry to visualize the details of FVIIa activation by comparing the exchange kinetics...

  4. Critical assessment of chitosan as coagulant to remove cyanobacteria

    NARCIS (Netherlands)

    Lürling, Miquel; Noyma, Natalia Pessoa; Magalhães, Leonardo de; Miranda, Marcela; Mucci, Maíra; Oosterhout, Frank van; Huszar, Vera L.M.; Marinho, Marcelo Manzi

    2017-01-01

    Removal of cyanobacteria from the water column using a coagulant and a ballast compound is a promising technique to mitigate nuisance. As coagulant the organic, biodegradable polymer chitosan has been promoted. Results in this study show that elevated pH, as may be common during cyanobacterial

  5. Optimization of coagulation-flocculation process for colour removal ...

    African Journals Online (AJOL)

    Overlay contour plot was used to establish an optimum condition for the multiple responses studied. The response surface approach was appropriate for optimizing the coagulation-flocculation process while minimizing the number of experiments. Coagulants studied should be considered as an alternative for conventional ...

  6. Disseminated intravascular coagulation in meningococcal sepsis. Case 7

    NARCIS (Netherlands)

    Zeerleder, S.; Zürcher Zenklusen, R.; Hack, C. E.; Wuillemin, W. A.

    2003-01-01

    We report on a man (age: 49 years), who died from severe meningococcal sepsis with disseminated intravascular coagulation (DIC), multiple organ dysfunction syndrome and extended skin necrosis. We discuss in detail the pathophysiology of the activation of coagulation and fibrinolysis during sepsis.

  7. Treatment of ink-containing wastewater by coagulation/flocculation ...

    African Journals Online (AJOL)

    A coagulation/flocculation process using a selection of biopolymers (chitosan and tannin) was used to treat an ink-containing effluent generated in the processing of packaging. The efficiency of the process was investigated in terms of the influence of pH, coagulant and flocculant concentrations, as well as chitosan ...

  8. Corrosion behaviour of sintered duplex stainless steels

    Energy Technology Data Exchange (ETDEWEB)

    Utrilla, M. Victoria; Urena, Alejandro; Otero, Enrique; Munez, Claudio Jose [Escuela Superior de Ciencias Experimentales y Tecnologia, Universidad Rey Juan Carlos, C/ Tulipan s/n, 28933 Mostoles, Madrid (Spain)

    2004-07-01

    Duplex austenite-ferrite stainless steels were prepared by mixing austenitic (316L) and ferritic (434L) atomized powders. Although different 316L/434L ratios were prepared, present work centred its study on 50% ferrite - 50% austenite sintered steel. The powders were mixed and pressed at 700 MPa and sintered at 1250 deg. C for 30 min in vacuum. The cooling rate was 5 deg. C/min. Solution treatment was carried out to homogenize the microstructure at 1100 deg. C during 20 min. A microstructural study of the material in solution was performed, evaluating the microstructure, proportion and shape of porosity, and ferrite percentage. This last was measured by two methods, quantitative metallography and Fischer ferrito-metry. The materials were heat treated in the range of 700 to 1000 deg. C, for 10, 30 and 60 min and water quenched, to study the microstructural changes and the influence on the intergranular corrosion resistance. The method used to evaluate the sensitization to the intergranular corrosion was the electrochemical potentio-kinetic reactivation procedure (EPR). The test solution was 0.5 M H{sub 2}SO{sub 4} + 0,01 M KSCN at 30 deg. C. The criterion used to evaluate the sensitization was the ratio between the maximum reactivation density (Ir) and the maximum activation density (Ia). The results of the electrochemical tests were discussed in relation with the microstructures observed at the different heat treatments. (authors)

  9. Adherence and Coagulation Assays in Dabigatran-treated Patients With Atrial Fibrillation

    Science.gov (United States)

    2017-09-12

    Atrial Fibrillation; Medication Adherence; Blood Coagulation Tests; Anticoagulants; Circulating, Hemorrhagic Disorder; Drug Effect; Drug Use; Drug Toxicity; Drug Intolerance; Blood Clot; Blood Coagulation Disorder; Laboratory Problem; Bleeding; Thrombosis

  10. The Emergence of Quantitative Sintering Theory from 1945 to 1955

    Science.gov (United States)

    German, Randall M.

    2017-04-01

    Particles flow and pack under stress, allowing shaping of the particles into target engineering geometries. Subsequently, in a process termed sintering, the particles are heated to induce bonding that results in a strong solid. Although first practiced 26,000 years ago, sintering was largely unexplained until recent times. Sintering science moved from an empirical and largely qualitative notion into a quantitative theory over a relatively short time period following World War II. That conceptual transition took place just as commercial applications for sintered materials underwent significant growth. This article highlights the key changes in sintering concepts that occurred in the 1945-1955 time period. This time span starts with the first quantitative neck growth model from Frenkel and ends with the quantitative shrinkage model from Kingery and Berg that includes several transport mechanisms.

  11. Preliminary investigation of liquid phase sintering in ferrous systems

    International Nuclear Information System (INIS)

    Klein, J.

    1975-04-01

    Liquid phase sintering was utilized to achieve, by a simple compaction and sintering procedure involving short times and moderate temperatures, a virtually full dense high carbon Fe:C alloy and high boron Fe:B alloy. Parameters such as powder characteristics and mixing, compacting pressure, heating program and the liquid phase fraction were found to influence the sintered density. The response of the Fe:C alloy to a heat treatment is reported along with preliminary experiments in the iron base ternary system Fe:W:C. Residual porosities observed in microstructures of certain liquid phase sintered compacts were accounted for by a proposed capillary flow of the liquid phase and a local densification competing against an overall densification. Some general recommendations are made for liquid phase sintering of powder aggregates. 15 fig., 7 tables

  12. Sintering with a chemical reaction as applied to uranium monocarbide

    International Nuclear Information System (INIS)

    Accary, A.; Caillat, R.

    1960-01-01

    The present paper provides a survey of different investigations whose aim was the preparation and fabrication of uranium monocarbide for nuclear use. If a chemical reaction takes place in the sample during the sintering operation, it may be expected that the atom rearrangements involved in this reaction should favour the sintering process and thereby lower the temperature needed to yield a body of a given density. With this hypothesis in mind, the following methods have been studied: - Sintering of U-C mixtures; - Sintering of UO 2 -C mixtures; - Hot pressing of U-C mixtures; - Extrusion of U-C mixtures. To generalize our result, it could be said that a chemical reaction does not lead to high densification, if one depends on a simple contact between discrete particles. On the contrary, a chemical reaction can help sintering if, as our hot pressing experiments shows, the densification can be achieved prior to the reaction. (author) [fr

  13. Sintered silver joints via controlled topography of electronic packaging subcomponents

    Science.gov (United States)

    Wereszczak, Andrew A.

    2014-09-02

    Disclosed are sintered silver bonded electronic package subcomponents and methods for making the same. Embodiments of the sintered silver bonded EPSs include topography modification of one or more metal surfaces of semiconductor devices bonded together by the sintered silver joint. The sintered silver bonded EPSs include a first semiconductor device having a first metal surface, the first metal surface having a modified topography that has been chemically etched, grit blasted, uniaxial ground and/or grid sliced connected to a second semiconductor device which may also include a first metal surface with a modified topography, a silver plating layer on the first metal surface of the first semiconductor device and a silver plating layer on the first metal surface of the second semiconductor device and a sintered silver joint between the silver plating layers of the first and second semiconductor devices which bonds the first semiconductor device to the second semiconductor device.

  14. Intense pulsed light sintering of copper nanoink for printed electronics

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Hak-Sung; Dhage, Sanjay R.; Shim, Dong-Eun [University of California, Mechanical and Aerospace Engineering Department, Los Angeles, CA (United States); Hahn, H.T. [University of California, Mechanical and Aerospace Engineering Department, Los Angeles, CA (United States); University of California, Material Science and Engineering Department, California NanoSystems Institute, Los Angeles, CA (United States)

    2009-12-15

    An intense pulsed light (IPL) from a xenon flash lamp was used to sinter copper nanoink printed on low-temperature polymer substrates at room temperature in ambient condition. The IPL can sinter the copper nanoink without damaging the polymer substrates in extremely short time (2 ms). The microstructure of the sintered copper film was investigated using X-ray powder diffraction (XRD), optical microscopy, scanning electron microscopy (SEM), X-ray micro tomography, and atomic force microscopy (AFM). The sintered copper film has a grainy structure with neck-like junctions. The resulting resistivity was 5{mu}{omega} cm of electrical resistivity which is only 3 times as high as that of bulk copper. The IPL sintering technique allows copper nanoparticles to be used in inkjet printing on low-temperature substrates such as polymers in ambient conditions. (orig.)

  15. Microstructure evolution during pressureless sintering of bulk oxide ceramics

    Directory of Open Access Journals (Sweden)

    Karel Maca

    2009-06-01

    Full Text Available The author’s experience concerning the infl uence of the choice of different pressureless heating schedules on the fi nal microstructure of oxide ceramic materials is summarized in the paper. Alumina, ceria, strontium titanate, as well as tetragonal (3 mol% Y2O3 and cubic (8 mol% Y2O3 zirconia were cold isostatically pressed or injection moulded and pressureless sintered with different heating schedules – namely with Constant-Rate of Heating with different dwell temperatures (CRH, with Rate-Controlled Sintering (RCS and with Two-Step Sintering (TSS. It was examined whether some of these three sintering schedules, with the same fi nal density achieved, can lead to a decrease of the grain size of sintered ceramics. The results showed that only TSS (and only for selected materials brought significant decrease of the grain size.

  16. Ash chemistry and sintering, verification of the mechanisms

    Energy Technology Data Exchange (ETDEWEB)

    Hupa, M.; Skrifvars, B.J.; Backman, R.; Lauren, T.; Uusikartano, T.; Malm, H.; Stenstroem, P.; Vesterkvist, M. [Aabo Akademi, Turku (Finland). Combustion Chemistry Research Group

    1997-10-01

    In this project four sintering mechanisms have been studied, i.e., partial melting with a viscous liquid, partial melting with a non-viscous liquid, chemical reaction sintering and solid state sintering. The work has aimed at improving the understanding of ash sintering mechanisms and quantifying their role in combustion and gasification. The work has been oriented in particular on the understanding of biomass ash behavior. The work has not directly focused on any specific technical application. However, results can also be applied on other fuels such as brown coal, petroleum coke, black liquor and different types of wastes (PDF, RDF, MSW). During 1996 the work has focused on identifying bed agglomeration mechanisms and analysing bed agglomerates in both full scale and lab scale FB reactors, as well as comparing how well the compression strength based sintering test can predict bed agglomeration in an FB furnace. (orig.)

  17. Study on selective laser sintering of glass fiber reinforced polystyrene

    Science.gov (United States)

    Yang, Laixia; Wang, Bo; Zhou, Wenming

    2017-12-01

    In order to improve the bending strength of Polystyrene (PS) sintered parts by selective laser sintering, Polystyrene/glass fiber (PS/GF) composite powders were prepared by mechanical mixing method. The size distribution of PS/GF composite powders was characterized by laser particle size analyzer. The optimum ratio of GF was determined by proportioning sintering experiments. The influence of process parameters on the bending strength of PS and PS/GF sintered parts was studied by orthogonal test. The result indicates that the particle size of PS/GF composite powder is mainly distributed in 24.88 μm~139.8 μm. When the content of GF is 10%, it has better strengthen effect. Finally, the article used the optimum parameter of the two materials to sinter prototype, it is found that the PS/GF prototype has the advantages of good accuracy and high strength.

  18. Powder metallurgy: Solid and liquid phase sintering of copper

    Science.gov (United States)

    Sheldon, Rex; Weiser, Martin W.

    1993-01-01

    Basic powder metallurgy (P/M) principles and techniques are presented in this laboratory experiment. A copper based system is used since it is relatively easy to work with and is commercially important. In addition to standard solid state sintering, small quantities of low melting metals such as tin, zinc, lead, and aluminum can be added to demonstrate liquid phase sintering and alloy formation. The Taguchi Method of experimental design was used to study the effect of particle size, pressing force, sintering temperature, and sintering time. These parameters can be easily changed to incorporate liquid phase sintering effects and some guidelines for such substitutions are presented. The experiment is typically carried out over a period of three weeks.

  19. Coagulation profile in open and video-assisted thoracoscopic lobectomies

    DEFF Research Database (Denmark)

    Christensen, Thomas Decker; Vad, Henrik; Pedersen, Søren

    2018-01-01

    OBJECTIVES: Lung cancer patients are perceived to have a relatively high risk of venous thromboembolic events due to an activation of the coagulation system. In terms of activation of the coagulation system, the difference between video-assisted thoracoscopic surgery (VATS) and open lobectomies...... for primary lung cancer has not been investigated. The aim of this study was to compare the impact on the coagulation system in patients undergoing curative surgery for primary lung cancer by either VATS or open lobectomies. METHODS: In total, 62 patients diagnosed with primary lung cancer were allocated...... to either VATS (n = 32) or open lobectomies (n = 30). All patients received subcutaneous injections with dalteparin (Fragmin®) 5000 IE once daily. The coagulation was assessed pre- and intraoperatively, and the first 2 days postoperatively by standard coagulation blood tests, thromboelastometry (ROTEM...

  20. Performance and characterization of a new tannin-based coagulant

    Science.gov (United States)

    Beltrán-Heredia, J.; Sánchez-Martín, J.; Gómez-Muñoz, C.

    2012-09-01

    Diethanolamine and formaldehyde were employed to cationize tannins from black wattle. This novel coagulant called CDF was functionally characterized in removing sodium dodecylbenzene sulfonate (anionic surfactant) and Palatine Fast Black WAN (azoic dye). Refined tannin-derived commercial coagulants exhibited similar efficiency, while CDF presented higher coagulant ability than alum, a usual coagulant agent. Low doses of CDF (ca. 100 mg L-1) were able to remove more than 70 % of surfactant and more than 85 % of dye (initial pollutant concentration of ca. 100 mg L-1) and it presented no temperature affection and worked at a relatively wide pH range. Surfactant and dye removal responded to the classical coagulant-and-adsorption models, such as Frumkin-Fowler-Guggenheim or Gu and Zhu in the case of surfactant, and Langmuir and Freundlich in the case of dye.

  1. Interplay between coagulation and vascular inflammation in sickle cell disease

    Science.gov (United States)

    Sparkenbaugh, Erica; Pawlinski, Rafal

    2013-01-01

    Sickle cell disease is the most common inherited hematologic disorder that leads to the irreversible damage of multiple organs. Although sickling of red blood cells and vaso-occlusion are central to the pathophysiology of sickle cell disease the importance of hemolytic anemia and vasculopathy has been recently recognized. Hypercoagulation state is another prominent feature of sickle cell disease and is mediated by activation of both intrinsic and extrinsic coagulation pathways. Growing evidence demonstrates that coagulation may not only contribute to the thrombotic complications, but also to vascular inflammation associated with this disease. This article summarizes the role of vascular inflammation and coagulation activation, discusses potential mechanisms responsible for activation of coagulation and reviews recent data demonstrating the crosstalk between coagulation and vascular inflammation in sickle cell disease. PMID:23593937

  2. Host defense peptides of thrombin modulate inflammation and coagulation in endotoxin-mediated shock and Pseudomonas aeruginosa sepsis.

    Directory of Open Access Journals (Sweden)

    Martina Kalle

    Full Text Available Gram-negative sepsis is accompanied by a disproportionate innate immune response and excessive coagulation mainly induced by endotoxins released from bacteria. Due to rising antibiotic resistance and current lack of other effective treatments there is an urgent need for new therapies. We here present a new treatment concept for sepsis and endotoxin-mediated shock, based on host defense peptides from the C-terminal part of human thrombin, found to have a broad and inhibitory effect on multiple sepsis pathologies. Thus, the peptides abrogate pro-inflammatory cytokine responses to endotoxin in vitro and in vivo. Furthermore, they interfere with coagulation by modulating contact activation and tissue factor-mediated clotting in vitro, leading to normalization of coagulation responses in vivo, a previously unknown function of host defense peptides. In a mouse model of Pseudomonas aeruginosa sepsis, the peptide GKY25, while mediating a modest antimicrobial effect, significantly inhibited the pro-inflammatory response, decreased fibrin deposition and leakage in the lungs, as well as reduced mortality. Taken together, the capacity of such thrombin-derived peptides to simultaneously modulate bacterial levels, pro-inflammatory responses, and coagulation, renders them attractive therapeutic candidates for the treatment of invasive infections and sepsis.

  3. Three-dimensional simulation of viscous-flow agglomerate sintering.

    Science.gov (United States)

    Kirchhof, M J; Schmid, H -J; Peukert, W

    2009-08-01

    The viscous-flow sintering of different agglomerate particle morphologies is studied by three-dimensional computer simulations based on the concept of fractional volume of fluid. For a fundamental understanding of particle sintering characteristics, the neck growth kinetics in agglomerate chains and in doublets consisting of differently sized primary particles is investigated. Results show that different sintering contacts in agglomerates even during the first stages are not completely independent from each other, even though differences are small. The neck growth kinetics of differently sized primary particles is determined by the smaller one up to a size difference by a factor of approximately 2, whereas for larger size differences, the kinetics becomes faster. In particular, the agglomerate sintering kinetics is investigated for particle chains of different lengths and for different particle morphologies each having ten primary particles and nine initial sintering contacts. For agglomerate chains, the kinetics approximately can be normalized by using the radius of the fully coalesced sphere. In general, different agglomerate morphologies show equal kinetics during the first sintering stages, whereas during advanced stages, compact morphologies show significantly faster sintering progress than more open morphologies. Hence, the overall kinetics cannot be described by simply using constant morphology correction factors such as fractal dimension or mean coordination number which are used in common sintering models. However, for the first stages of viscous-flow agglomerate sintering, which are the most important for many particle processes, a sintering equation is presented. Although we use agglomerates consisting of spherical primary particles, our methodology can be applied to other aggregate geometries as well.

  4. Optimum coagulant forecasting by modeling jar test experiments using ANNs

    Science.gov (United States)

    Haghiri, Sadaf; Daghighi, Amin; Moharramzadeh, Sina

    2018-01-01

    Currently, the proper utilization of water treatment plants and optimizing their use is of particular importance. Coagulation and flocculation in water treatment are the common ways through which the use of coagulants leads to instability of particles and the formation of larger and heavier particles, resulting in improvement of sedimentation and filtration processes. Determination of the optimum dose of such a coagulant is of particular significance. A high dose, in addition to adding costs, can cause the sediment to remain in the filtrate, a dangerous condition according to the standards, while a sub-adequate dose of coagulants can result in the reducing the required quality and acceptable performance of the coagulation process. Although jar tests are used for testing coagulants, such experiments face many constraints with respect to evaluating the results produced by sudden changes in input water because of their significant costs, long time requirements, and complex relationships among the many factors (turbidity, temperature, pH, alkalinity, etc.) that can influence the efficiency of coagulant and test results. Modeling can be used to overcome these limitations; in this research study, an artificial neural network (ANN) multi-layer perceptron (MLP) with one hidden layer has been used for modeling the jar test to determine the dosage level of used coagulant in water treatment processes. The data contained in this research have been obtained from the drinking water treatment plant located in Ardabil province in Iran. To evaluate the performance of the model, the mean squared error (MSE) and correlation coefficient (R2) parameters have been used. The obtained values are within an acceptable range that demonstrates the high accuracy of the models with respect to the estimation of water-quality characteristics and the optimal dosages of coagulants; so using these models will allow operators to not only reduce costs and time taken to perform experimental jar tests

  5. Magnetic and structural properties of spark plasma sintered nanocrystalline NdFeB-powders

    Energy Technology Data Exchange (ETDEWEB)

    Wuest, H., E-mail: holger.wuest@de.bosch.com [Robert Bosch GmbH, Postfach 10 60 50, 70049 Stuttgart (Germany); Bommer, L., E-mail: lars.bommer@de.bosch.com [Robert Bosch GmbH, Postfach 10 60 50, 70049 Stuttgart (Germany); Weissgaerber, T., E-mail: thomas.weissgaerber@ifam-dd.fraunhofer.de [Fraunhofer Institute for Manufacturing Technology and Advanced Materials (IFAM), Branch Lab Dresden, Winterbergstraße 28, 01277 Dresden (Germany); Kieback, B., E-mail: bernd.kieback@ifam-dd.fraunhofer.de [Fraunhofer Institute for Manufacturing Technology and Advanced Materials (IFAM), Branch Lab Dresden, Winterbergstraße 28, 01277 Dresden (Germany); Technische Universität Dresden, Institute for Materials Science, Helmholtzstraße 7, 01069 Dresden (Germany)

    2015-10-15

    Near-stoichiometric NdFeB melt-spun ribbons have been subjected to spark plasma sintering varying the process temperature T{sub SPS} and pressure p{sub SPS} between 600 and 800 °C and 50–300 MPa, respectively. Produced bulk magnets were analyzed regarding microstructure and magnetic properties. For all samples the intrinsic coercivity H{sub c,J} gradually decreases with increasing sintering temperature and pressure, while residual induction B{sub r} increases simultaneously with sample density. Densities close to the theoretical limit were achieved for p{sub SPS}≥90 MPa and T{sub SPS}≥650 °C. With increasing T{sub SPS} precipitations of Nd-rich and Fe-rich phases have been observed as a result of a decomposition of the hard magnetic Nd{sub 2}Fe{sub 14}B phase. Under optimum sintering conditions of p{sub SPS}=300 MPa and T{sub SPS}=650 °C high-density bulk magnets with H{sub c,J}=652 kA/m, B{sub r}=0.86 T and (BH){sub max}=106 kJ/m{sup 3} have been produced. - Highlights: • Consolidation close to the theoretical density for p{sub SPS}≥90 MPa and T{sub SPS}≥650 °C. • Highest (BH){sub max} of 106 kJ/m{sup 3} for p{sub SPS}=300 MPa and T{sub SPS}=650 °C with 98% theo. • H{sub c,J} gradually decreases with increasing T{sub SPS}, while B{sub r} increases simultaneously with. • With increasing T{sub SPS}, Nd- and Fe-rich precipitations are observed. • Reduction in t{sub SPS} is economic but does not increase (BH){sub max} significantly.

  6. Effect of sintering conditions on the electrical properties of Ni{sub 1-x}Zn{sub x}La{sub 0.05}Fe{sub 1.95}O{sub 4}

    Energy Technology Data Exchange (ETDEWEB)

    Ahmed, M.A.; Ateia, E.; Salah, L.M.; El-Gamal, A.A. [Physics Department, Faculty of Science, Cairo University, Giza (Egypt)

    2004-10-01

    Ferrite samples having the general formula Ni{sub 1-x}Zn{sub x}La{sub 0.05}Fe{sub 1.95}O{sub 4} were prepared using the standard ceramic method. The effect of sintering temperature, heating rate, and sintering time on the structural and the electrical properties was studied. The data show that electrical conductivity ln {sigma} as well as dielectric constant {epsilon}' are highly dependent on both Zn content x and the sintering conditions. The data obtained show that 1250 C is a critical sintering temperature. At this sintering temperature the grain growth is increased as the formation of spinel structure reaches its maximum value, and the volume diffusion is predominant. The critical heating rate is 4 C/min where the full reaction and maximum densification occur simultaneously. The effect of sintering time was also studied at a constant heating rate of 4 C/min and sintering temperature of 1250 C. All the data obtained are nearly constant and begin to increase after 83 h. SEM and electrical properties confirmed the results obtained. (copyright 2004 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  7. Contact activation of blood-plasma coagulation

    Science.gov (United States)

    Golas, Avantika

    Surface engineering of biomaterials with improved hemocompatibility is an imperative, given the widespread global need for cardiovascular devices. Research summarized in this dissertation focuses on contact activation of FXII in buffer and blood plasma frequently referred to as autoactivation. The extant theory of contact activation imparts FXII autoactivation ability to negatively charged, hydrophilic surfaces. According to this theory, contact activation of plasma involves assembly of proteins comprising an "activation complex" on activating surfaces mediated by specific chemical interactions between complex proteins and the surface. This work has made key discoveries that significantly improve our core understanding of contact activation and unravel the existing paradigm of plasma coagulation. It is shown herein that contact activation of blood factor XII (FXII, Hageman factor) in neat-buffer solution exhibits a parabolic profile when scaled as a function of silanized-glass-particle activator surface energy (measured as advancing water adhesion tension t°a=g° Iv costheta in dyne/cm, where g°Iv is water interfacial tension in dyne/cm and theta is the advancing contact angle). Nearly equal activation is observed at the extremes of activator water-wetting properties --36 < t°a < 72 dyne/cm (O° ≤ theta < 120°), falling sharply through a broad minimum within the 20 < t°a < 40 dyne/cm (55° < theta < 75°). Furthermore, contact activation of FXII in buffer solution produces an ensemble of protein fragments exhibiting either procoagulant properties in plasma (proteolysis of blood factor XI or prekallikrein), amidolytic properties (cleavage of s-2302 chromogen), or the ability to suppress autoactivation through currently unknown biochemistry. The relative proportions of these fragments depend on activator surface chemistry/energy. We have also discovered that contact activation is moderated by adsorption of plasma proteins unrelated to coagulation through an

  8. Quinine-Induced Disseminated Intravascular Coagulation

    Directory of Open Access Journals (Sweden)

    Firas Abed

    2016-01-01

    Full Text Available Every drug comes with some side effect. It is the benefit/risk ratio that determines the medical use of the drug. Quinine, a known antimalarial drug, has been used for nocturnal leg cramps since the 1930s; it is associated with severe life-threatening hematological and cardiovascular side effects. Disseminated intravascular coagulation (DIC, albeit rare, is a known coagulopathy associated with Quinine. It is imperative to inquire about the Quinine intake in medication history in patients with coagulopathy, as most patients still consider it a harmless home remedy for nocturnal leg cramps. In this report, we present a case of coagulopathy in a middle-aged woman, who gave a history of taking Quinine for nocturnal leg cramps, as her home remedy. Early identification of the offending agent led to the diagnosis, prompt discontinuation of the medication, and complete recovery and prevented the future possibility of recurrence.

  9. Treatment of Textile Wastewaterby Adsorption and Coagulation

    Directory of Open Access Journals (Sweden)

    Himanshu Patel

    2010-01-01

    Full Text Available The composite of wastewater treatment was carried out using activated charcoal as adsorbent to remove COD, BOD, color in which various parameters like adsorbent dose, contact duration, temperature and agitator speed were considered. The adsorbent behavior can be explained on the basis of Freundlich and Langmuir adsorption isotherm model. Maximum removal (87.6, 81.0 and 90.0% of COD, BOD and color respectively was found at adsorbent dosage of 11 g/L. Also, the textile mill wastewater was treated with different doses of coagulants like alum, ferric sulphate and ferrous sulphate at constant contact duration (4 hours and room temperature (300 K. Percentage reduction (maximum corresponds to 80.2, 74.0 and 84.9% was obtained for removal of COD, BOD and color respectively.

  10. Optimized alumina coagulants for water treatment

    Science.gov (United States)

    Nyman, May D [Albuquerque, NM; Stewart, Thomas A [Albuquerque, NM

    2012-02-21

    Substitution of a single Ga-atom or single Ge-atom (GaAl.sub.12 and GeAl.sub.12 respectively) into the center of an aluminum Keggin polycation (Al.sub.13) produces an optimal water-treatment product for neutralization and coagulation of anionic contaminants in water. GaAl.sub.12 consistently shows .about.1 order of magnitude increase in pathogen reduction, compared to Al.sub.13. At a concentration of 2 ppm, GaAl.sub.12 performs equivalently to 40 ppm alum, removing .about.90% of the dissolved organic material. The substituted GaAl.sub.12 product also offers extended shelf-life and consistent performance. We also synthesized a related polyaluminum chloride compound made of pre-hydrolyzed dissolved alumina clusters of [GaO.sub.4Al.sub.12(OH).sub.24(H.sub.2O).sub.12].sup.7+.

  11. Sintered soft magnetic materials. Properties and applications

    Science.gov (United States)

    Bas, J. A.; Calero, J. A.; Dougan, M. J.

    2003-01-01

    A comparison is presented of the characteristics and production requirements of a variety of materials used to produce sintered soft magnetic parts. These include pure iron, phosphorous-iron, silicon-iron, nickel-iron, and cobalt-iron, together with new coated materials based on encapsulated iron powders. In these bonded materials an organic and/or inorganic insulator is used to coat the metallic powder particles giving a magnetic composite. The suitability of the different materials for use in both direct and alternating current applications is reviewed, and examples are provided of their application in both the automotive and other sectors. The results of a comparative study of motors using stators and rotors based on both conventional laminated materials and the insulated iron powders are presented, in which the new materials show advantages of reduced hysteresis losses at high frequencies, and isotropy of magnetic properties. Nevertheless, the applications of these materials in electrical motors requires the modification of existing designs.

  12. Sintering and microstructure evolution in columnar thermal barrier coatings

    International Nuclear Information System (INIS)

    Krishnamurthy, Ramanathan; Srolovitz, David J.

    2009-01-01

    Sintering of thermal barrier coatings changes their key properties, such as thermal conductivity and thermal shock resistance, thus adversely impacting their reliability. We present a novel modeling approach to study the evolution of coating structure during sintering. We model the sintering of individual columns using a thermodynamic principle, and incorporate the center-to-center approach rates for the columns calculated using this principle in a larger scale discrete dynamics model for the evolution of a large number of columns. Surface energies, grain boundary energies and strain energies associated with the deformation of the columns are all included in this framework, while sintering is assumed to occur by the concerted action of surface and grain boundary diffusion. Two sets of initial conditions corresponding to different extents of pre-sintering among neighboring columns are considered. When the extent of pre-sintering is small, we observe that small clusters containing 5-20 columns are formed. In contrast, where a larger amount of pre-sintering exists, we observe, especially at large column densities, that clusters containing 50-100 columns separated by large inter-cluster pores/channels that appear to organize themselves into a network are formed. These observations are in good agreement with recently published experimental observations. We also explain how these results can explain the development of a 'mud-crack'-like pattern

  13. Embrittling Components in Sintered Steels: Comparison of Phosphorus and Boron

    Science.gov (United States)

    Danninger, Herbert; Vassileva, Vassilka; Gierl-Mayer, Christian

    2017-12-01

    In ferrous powder metallurgy, both boron and phosphorus have been known to be sintering activators for a long time. However, the use has been widely different: while P is a standard additive to sintered iron and steels, boron has been frequently studied, but its use in practice is very limited. Both additives are also known to be potentially embrittling, though in a different way. In the present study the differences between the effects of both elements are shown: while P activates sintering up to a certain threshold, in part by stabilizing ferrite, in part by forming a transient liquid phase, boron is the classical additive enhancing persistent liquid phase, being virtually insoluble in the iron matrix. The consequence is that sintered steels can tolerate quite a proportion of phosphorus, depending on composition and sintering process; boron however is strongly embrittling in particular in combination with carbon, which requires establishing a precisely defined content that enhances sintering but is not yet embrittling. The fracture mode of embrittled materials is also different: while with Fe-P the classical intergranular fracture is observed, with boron a much more rugged fracture surface appears, indicating some failure through the eutectic interparticle network but mostly transgranular cleavage. If carbon is added, in both cases transgranular cleavage dominates even in the severely embrittled specimens, indicating that no more the grain boundaries and sintering necks are the weakest links in the systems.

  14. Coagulation pretreatment of highly concentrated acrylonitrile wastewater from petrochemical plants.

    Science.gov (United States)

    Zheng, Dongju; Qin, Lin; Wang, Tao; Ren, Xiaojing; Zhang, Zhongguo; Li, Jiding

    2014-01-01

    Acrylonitrile (AN) wastewater is a heavily polluted and a likely hazardous liquid that is generated during the production of AN. Several chemical methods for the pretreatment of AN wastewater are available in laboratory scale. However, the harsh reaction conditions and high operational cost make these methods undesirable. Until now, four-effect evaporation is the only pretreatment method used for AN wastewater in industry despite its huge energy consumption and high cost. It is difficult to find an energy-saving pretreatment technique from the perspective of industrial application. In this study, a safe and low-cost coagulation technique was developed for the pretreatment of AN wastewater. Three types of inorganic coagulant and three types of polymer coagulant were investigated for the coagulation treatment of highly concentrated AN wastewater from petrochemical plants. The effects of coagulant type, dosage, and coagulation conditions on the pretreatment efficiency of AN wastewater were investigated. The results show that a combination of inorganic and polymer coagulants is effective for the pretreatment of AN wastewater.

  15. Treatment of waste water by coagulation and flocculation using biomaterials

    Science.gov (United States)

    Muruganandam, L.; Saravana Kumar, M. P.; Jena, Amarjit; Gulla, Sudiv; Godhwani, Bhagesh

    2017-11-01

    The present study deals with the determination of physical and chemical parameters in the treatment process of waste water by flocculation and coagulation processes using natural coagulants and assessing their feasibility for water treatment by comparing the performance with each other and with a synthetic coagulant. Initial studies were done on the synthetic waste water to determine the optimal pH and dosage, the activity of natural coagulant, followed by the real effluent from tannery waste. The raw tannery effluent was bluish-black in colour, mildly basic in nature, with high COD 4000mg/l and turbidity in the range 700NTU, was diluted and dosed with organic coagulants, AloeVera, MoringaOleifera and Cactus (O.ficus-indica). The study observed that coagulant Moringa Oleifera of 15 mg/L dose at 6 pH gave the best reduction efficiencies for major physicochemical parameters followed by Aloe Vera and Cactus under identical conditions. The study reveals that the untreated tannery effluents can be treated with environmental confirmative naturally occurring coagulants.

  16. Nanoparticles and the blood coagulation system. Part II: safety concerns

    Science.gov (United States)

    Ilinskaya, Anna N; Dobrovolskaia, Marina A

    2014-01-01

    Nanoparticle interactions with the blood coagulation system can be beneficial or adverse depending on the intended use of a nanomaterial. Nanoparticles can be engineered to be procoagulant or to carry coagulation-initiating factors to treat certain disorders. Likewise, they can be designed to be anticoagulant or to carry anticoagulant drugs to intervene in other pathological conditions in which coagulation is a concern. An overview of the coagulation system was given and a discussion of a desirable interface between this system and engineered nanomaterials was assessed in part I, which was published in the May 2013 issue of Nanomedicine. Unwanted pro- and anti-coagulant properties of nanoparticles represent significant concerns in the field of nanomedicine, and often hamper the development and transition into the clinic of many promising engineered nanocarriers. This part will focus on the undesirable effects of engineered nanomaterials on the blood coagulation system. We will discuss the relationship between the physicochemical properties of nanoparticles (e.g., size, charge and hydrophobicity) that determine their negative effects on the blood coagulation system in order to understand how manipulation of these properties can help to overcome unwanted side effects. PMID:23730696

  17. Seawater pretreatment for reverse osmosis: chemistry, contaminants, and coagulation.

    Science.gov (United States)

    Edzwald, James K; Haarhoff, Johannes

    2011-11-01

    The paper addresses the effects of salinity and temperature on the chemistry of important parameters affecting coagulation pretreatment including the ion product of water, acid-base chemistry, dissolved metal speciation, and precipitation reactions for aluminum and iron coagulants. The ion product of seawater is greater than for freshwaters and affects chemical hydrolysis and metal-hydroxide solubility reactions. Inorganic carbon is the main cause of seawater alkalinity and buffer intensity but borate B(OH)(4)(1-) also contributes. Buffer intensity is an important parameter in assessing coagulation pH adjustment. Mineral particles are relatively unstable in seawater from electrical double layer compression, and when present these particles are easily coagulated. Algal-particle stability is affected by steric effects and algal motility. Dissolved natural organic matter from algae and humic substances causes fouling of RO membranes and pretreatment removal is essential. Aluminum coagulants are not recommended, and not used, because they are too soluble in seawater. Ferric coagulants are preferred and used. The equilibrium solubility of Fe with amorphous ferric hydroxide in seawater is low over a wide range of pH and temperature conditions. Ferric chloride dosing guidelines are presented for various raw seawater quality characteristics. The effect of pH on coagulant dose and the role of buffer intensity are addressed. A dual coagulation strategy is recommended for treating seawater with moderate to high concentrations of algae or seawater with humic matter. This involves a low and constant dose with high charge-density cationic polymers using Fe as the main coagulant where it is varied in response to raw water quality changes. Copyright © 2011 Elsevier Ltd. All rights reserved.

  18. Electromagnetic induction sensor for dynamic testing of coagulation process.

    Science.gov (United States)

    Wang, Zhe; Yu, Yuanhua; Yu, Zhanjiang; Chen, Qimeng

    2018-03-01

    With the increasing demand for coagulation POCT for patients in the surgery department or the ICU, rapid coagulation testing techniques and methods have drawn widespread attention from scholars and businessmen. This paper proposes the use of electromagnetic induction sensor probe for detection of dynamic process causing changes in the blood viscosity and density before and after coagulation based on the damped vibration principle, in order to evaluate the coagulation status. Utilizing the dynamic principle, the differential equation of vibration system comprising elastic support and electromagnetic induction device is established through sensor dynamic modeling. The structural parameters of elastic support are optimized, and the circular sheet spring is designed. Furthermore, harmonic response analysis and vibration fatigue coupling analysis are performed on the elastic support of the sensor by considering the natural frequency of the system, and the electromagnetic induction sensor testing device is set up. Using the device and coagulation reagent, the standard curve for coagulation POCT is plotted, and the blood sample application in clinical patients is established, which are methodologically compared with the imported POCT coagulation analyzer. The results show that the sensor designed in this paper has a first-order natural frequency of 11.368 Hz, which can withstand 5.295 × 10 2 million times of compressions and rebounds. Its correlation with the results of SONOCLOT analyzer reaches 0.996, and the reproducibility 0.002. The electromagnetic induction coagulation testing sensor designed has good elasticity and anti-fatigue, which can meet the accuracy requirement of clinical detection. This study provides the core technology for developing the electromagnetic induction POCT instrument for dynamic testing of coagulation process.

  19. Causal relationships between milk quality and coagulation properties in Italian Holstein-Friesian dairy cattle.

    Science.gov (United States)

    Tiezzi, Francesco; Valente, Bruno D; Cassandro, Martino; Maltecca, Christian

    2015-05-13

    Recently, selection for milk technological traits was initiated in the Italian dairy cattle industry based on direct measures of milk coagulation properties (MCP) such as rennet coagulation time (RCT) and curd firmness 30 min after rennet addition (a30) and on some traditional milk quality traits that are used as predictors, such as somatic cell score (SCS) and casein percentage (CAS). The aim of this study was to shed light on the causal relationships between traditional milk quality traits and MCP. Different structural equation models that included causal effects of SCS and CAS on RCT and a30 and of RCT on a30 were implemented in a Bayesian framework. Our results indicate a non-zero magnitude of the causal relationships between the traits studied. Causal effects of SCS and CAS on RCT and a30 were observed, which suggests that the relationship between milk coagulation ability and traditional milk quality traits depends more on phenotypic causal pathways than directly on common genetic influence. While RCT does not seem to be largely controlled by SCS and CAS, some of the variation in a30 depends on the phenotypes of these traits. However, a30 depends heavily on coagulation time. Our results also indicate that, when direct effects of SCS, CAS and RCT are considered simultaneously, most of the overall genetic variability of a30 is mediated by other traits. This study suggests that selection for RCT and a30 should not be performed on correlated traits such as SCS or CAS but on direct measures because the ability of milk to coagulate is improved through the causal effect that the former play on the latter, rather than from a common source of genetic variation. Breaking the causal link (e.g. standardizing SCS or CAS before the milk is processed into cheese) would reduce the impact of the improvement due to selective breeding. Since a30 depends heavily on RCT, the relative emphasis that is put on this trait should be reconsidered and weighted for the fact that the pure

  20. Effects of various additives on sintering of aluminum nitride

    Science.gov (United States)

    Komeya, K.; Inoue, H.; Tsuge, A.

    1982-01-01

    Effects of thirty additives on sintering A/N were investigated. The addition of alkali earth oxides and rare earth oxides gave fully densified aluminum nitride. This is due to the formation of nitrogen-containing aluminate liquid in the system aluminum nitride-alkali earth oxides or rare earth oxides. Microstructural studies of the sintered specimens with the above two types of additives suggested that the densification was due to the liquid phase sintering. Additions of silicon compounds resulted in poor densification by the formation of highly refractory compounds such as A/N polytypes.

  1. Low temperature spark plasma sintering of YIG powders

    International Nuclear Information System (INIS)

    Fernandez-Garcia, L.; Suarez, M.; Menendez, J.L.

    2010-01-01

    A transition from a low to a high spin state in the magnetization saturation between 1000 and 1100 o C calcination temperature is observed in YIG powders prepared by oxides mixture. Spark plasma sintering of these powders between 900 and 950 o C leads to dense samples with minimal formation of YFeO 3 , opening the way to co-sintering of YIG with metals or metallic alloys. The optical properties depend on the sintering stage: low (high) density samples show poor (bulk) optical absorption.

  2. Phenomenological theory of sintering and its application to swelling

    Directory of Open Access Journals (Sweden)

    Kornyushin Y.

    2004-01-01

    Full Text Available The general phenomenological theory of sintering, formulated by the author in 1998 is applied to the problem of swelling. Driving forces, caused by the presence of the evolution of heat in the volume of a sample (electric contact, hf, inductive heating or penetrating radiation, e.g., neutrons could be the sources of the heat in the bulk of a sample are considered. The influence of these driving forces on sintering, structure and properties is discussed. The role of mobile and immobile dislocations, grain boundaries, and pores is considered. Cycling and pulsing regimes of sintering are investigated.

  3. Microwave sintering of nanophase ceramics without concomitant grain growth

    Science.gov (United States)

    Eastman, Jeffrey A.; Sickafus, Kurt E.; Katz, Joel D.

    1993-01-01

    A method of sintering nanocrystalline material is disclosed wherein the nanocrystalline material is microwaved to heat the material to a temperature less than about 70% of the melting point of the nanocrystalline material expressed in degrees K. This method produces sintered nanocrystalline material having a density greater than about 95% of theoretical and an average grain size not more than about 3 times the average grain size of the nanocrystalline material before sintering. Rutile TiO.sub.2 as well as various other ceramics have been prepared. Grain growth of as little as 1.67 times has resulted with densities of about 90% of theoretical.

  4. Manufacturing of metal supported BSCF membranes by spark plasma sintering

    OpenAIRE

    Laptev, Alexander; Bram, Martin; Zivcec, Maria; Baumann, Stefan; Jarligo, Maria Ophelia; Sebold, Doris; Pfaff, Ewald; Broeckmann, Christoph

    2013-01-01

    Spark plasma sintering (SPS), also known as field assisted sintering technique (FAST), is a relatively new method for rapid consolidation of metallic or ceramic powders. In the present work, its suitability for the manufacturing of metal supported Ba0.5Sr0.5Co0.8Fe0.2O3-δ (BSCF) based membrane by co-sintering of functional ceramic BSCF layer and porous metallic support has been investigated. The BSCF based membranes are highly attractive for oxygen separation from air due to mixed ionic and e...

  5. Cleanable sintered metal filters in hot off-gas systems

    International Nuclear Information System (INIS)

    Schurr, G.A.

    1981-01-01

    Filters with sintered metal elements, arranged as tube bundles with backflush air cleaning, are the equivalent of bag filters for high-temperature, harsh environments. They are virtually the only alternative for high-temperature off-gas systems where a renewable, highly efficient particle trap is required. Tests were conducted which show that the sintered metal elements installed in a filter system provide effective powder collection in high-temperature atmospheres over thousands of cleaning cycles. Such a sintered metal filter system is now installed on the experimental defense waste calciner at the Savannah River Laboratory. The experimental results included in this paper were used as the basis for its design

  6. Low temperature spark plasma sintering of YIG powders

    Energy Technology Data Exchange (ETDEWEB)

    Fernandez-Garcia, L. [Department of Nanostructured Materials, Centro de Investigacion en Nanomateriales y Nanotecnologia (CINN). Principado de Asturias - Consejo superior de Investigaciones Cientificas (CSIC) - Universidad de Oviedo - UO, Parque Tecnologico de Asturias, 33428 Llanera, Asturias (Spain); Suarez, M., E-mail: m.suarez@cinn.e [Department of Nanostructured Materials, Centro de Investigacion en Nanomateriales y Nanotecnologia (CINN). Principado de Asturias - Consejo superior de Investigaciones Cientificas (CSIC) - Universidad de Oviedo - UO, Parque Tecnologico de Asturias, 33428 Llanera, Asturias (Spain); Fundacion ITMA, Parque Tecnologico de Asturias, 33428, Llanera (Spain); Menendez, J.L. [Department of Nanostructured Materials, Centro de Investigacion en Nanomateriales y Nanotecnologia (CINN). Principado de Asturias - Consejo superior de Investigaciones Cientificas (CSIC) - Universidad de Oviedo - UO, Parque Tecnologico de Asturias, 33428 Llanera, Asturias (Spain)

    2010-07-16

    A transition from a low to a high spin state in the magnetization saturation between 1000 and 1100 {sup o}C calcination temperature is observed in YIG powders prepared by oxides mixture. Spark plasma sintering of these powders between 900 and 950 {sup o}C leads to dense samples with minimal formation of YFeO{sub 3}, opening the way to co-sintering of YIG with metals or metallic alloys. The optical properties depend on the sintering stage: low (high) density samples show poor (bulk) optical absorption.

  7. Distribution functions and moments in the theory of coagulation

    International Nuclear Information System (INIS)

    Pich, J.

    1990-04-01

    Different distribution functions and their moments used in the Theory of coagulation are summarized and analysed. Relations between the moments of these distribution functions are derived and the physical meaning of individual moments is briefly discussed. The time evolution of the moment of order zero (total number concentration) during the coagulation process is analysed for the general kernel of the Smoluchowski equation. On this basis the time evolution of certain physically important quantities related to this moment such as mean particle size, surface and volume as well as surface concentration is described. Equations for the half time of coagulation for the general collision frequency factor are derived. (orig.) [de

  8. A loop of coagulation factor VIIa influencing macromolecular substrate specificity

    DEFF Research Database (Denmark)

    Bjelke, Jais R; Persson, Egon; Rasmussen, Hanne B

    2006-01-01

    Coagulation factor VIIa (FVIIa) belongs to a family of proteases being part of the stepwise, self-amplifying blood coagulation cascade. To investigate the impact of the mutation Met(298{156})Lys in FVIIa, we replaced the Gly(283{140})-Met(298{156}) loop with the corresponding loop of factor Xa....../Met(298{156})Lys-FVIIa with almost the same activity and specificity profile. We conclude that a lysine residue in position 298{156} of FVIIa requires a hydrophilic environment to be fully accommodated. This position appears critical for substrate specificity among the proteases of the blood coagulation...

  9. Usefulness of human coagulation and fibrinolysis assays in domestic pigs

    DEFF Research Database (Denmark)

    Münster, Anna-Marie Bloch; Olsen, Aage Kristian; Bladbjerg, Else-Marie

    2002-01-01

    Pigs are often used as animal models in research on blood coagulation and fibrinolysis. The usefulness of the assays applied within this field, and the knowledge of reference intervals are therefore essential and of utmost importance. In the study reported here, we investigated the applicability...... of commercial human coagulation and fibrinolysis assays for use with porcine plasma. In total, 22 functional and immunologic assays were applied to plasma obtained from domestic pigs, and the following blood coagulation and fibrinolysis variables were measured: prothrombin time, activated partial thromboplastin...

  10. Arsenic removal in water by means of coagulation-flocculation processes; Remocion de arsenico en agua mediante procesos de coagulacion-floculacion

    Energy Technology Data Exchange (ETDEWEB)

    Franco, M. F.; Carro P, M. E., E-mail: ffrancis@efn.uncor.edu [Universidad Nacional de Cordoba, Facultad de Ciencias Exactas, Fisicas y Naturales, Departamento de Construcciones Civiles, Av. Velez Sarsfield 1611, Cordoba (Argentina)

    2014-10-01

    Arsenic and arsenical compounds are considered as carcinogenic and risky for humans according to epidemiological evidence related with the ingestion of arsenical water during a long period. In many places the only source of drinking water contains arsenic and, therefore, removal strategies have to be investigated. This work shows experimental results of coagulation-flocculation processes implemented to evaluate the efficiency in the removal of arsenic from drinking water. The main objectives include the evaluation of the relevant aspect that controls the removal efficiency. Experimental tests were performed with coagulant concentrations from 5 to 500 mg/L, solid particle concentrations from 0 to 6000 mg/L, and initial arsenic concentrations from 0.5 to 5 mg/L. These variables were simultaneously varied in more than 100 experiments. The efficiency in remediation ranged from 0% to 95%. Removal efficiency near 95% was obtained when using ferric chloride as coagulant, and was close to 80% when using aluminium sulfate as coagulant in arsenate solutions. The remediation efficiency decreased significantly when the ferric chloride concentration was higher than 50 mg/L in relation to the obtained results for aluminum sulfate for different type and concentration of soil particles. The highest removal efficiency were obtained at ph between 3 and 5 in oxidized solutions. Obtained results simulated by means of multiple linear regression analysis (R>0.90) allow determining that the main parameters that control the removal of arsenic from drinking water are coagulant concentration, ph, and solid particles concentration. Conversely, particle mineralogy and coagulant type have less significant effect on the removal by means of coagulation-flocculation mechanisms. Obtained results are relevant for the removal of As in water treatment plants as well as for the development of small scale filters. The samples were studied by scanning electron microscopy and energy dispersive X

  11. Pretreatment of algae-laden and manganese-containing waters by oxidation-assisted coagulation: Effects of oxidation on algal cell viability and manganese precipitation.

    Science.gov (United States)

    Lin, Jr-Lin; Hua, Lap-Cuong; Wu, Yuting; Huang, Chihpin

    2016-02-01

    Preoxidation is manipulated to improve performance of algae and soluble manganese (Mn) removal by coagulation-sedimentation for water treatment plants (WTPs) when large amount of soluble Mn presents in algae-laden waters. This study aimed to investigate the effects of preoxidation on the performance of coagulation-sedimentation for the simultaneous removal of algae and soluble Mn, including ionic and complexed Mn. NaOCl, ClO2, and KMnO4 were used to pretreat such algae-laden and Mn containing waters. The variation of algal cell viability, residual cell counts, and concentrations of Mn species prior to and after coagulation-sedimentation step were investigated. Results show that NaOCl dosing was effective in reducing the viability of algae, but precipitated little Mn. ClO2 dosing had a strongest ability to lower algae viability and oxidize ionic and complexed soluble Mn, where KMnO4 dosing oxidized ionic and complexed Mn instead of reducing the viability of cells. Preoxidation by NaOCl only improved the algae removal by sedimentation, whereas most of soluble Mn still remained. On the other hand, ClO2 preoxidation substantially improved the performance of coagulation-sedimentation for simultaneous removal of algae and soluble Mn. Furthermore, KMnO4 preoxidation did improve the removal of algae by sedimentation, but left significant residual Mn in the supernatant. Images from FlowCAM showed changes in aspect ratio (AR) and transparency of algae-Mn flocs during oxidation-assisted coagulation, and indicates that an effective oxidation can improve the removal of most compact algae-Mn flocs by sedimentation. It suggests that an effective preoxidation for reducing algal cell viability and the concentration of soluble Mn is a crucial step for upgrading the performance of coagulation-sedimentation. Copyright © 2015 Elsevier Ltd. All rights reserved.

  12. The effectiveness of chitosan as coagulant aid in turbidity removal from water

    Directory of Open Access Journals (Sweden)

    Farid Hesami

    2014-01-01

    Conclusion: Chitosan as natural coagulant aid improved turbidity removal efficiency by coagulation process. And FeCl 3 concentration as coagulant was reduced then residual iron decreased in treated water. Also by using natural coagulant considerable savings in chemicals and sludge handling cost may be achieved.

  13. Randomized study of coagulation and fibrinolysis during and after gasless and conventional laparoscopic cholecystectomy

    DEFF Research Database (Denmark)

    Larsen, J F; Ejstrud, P; Svendsen, F

    2001-01-01

    BACKGROUND: Carbon dioxide pneumoperitoneum may be an important pathophysiological factor stimulating the coagulation system during conventional laparoscopic cholecystectomy. The aim of this study was to test the hypothesis that gasless laparoscopy produces smaller changes in the coagulation...... increased significantly in both groups (P coagulation and fibrinolysis associated with laparoscopic cholecystectomy. The coagulation and fibrinolytic systems are activated during and after gasless as well...

  14. Sintering equation: determination of its coefficients by experiments - using multiple regression

    International Nuclear Information System (INIS)

    Windelberg, D.

    1999-01-01

    Sintering is a method for volume-compression (or volume-contraction) of powdered or grained material applying high temperature (less than the melting point of the material). Maekipirtti tried to find an equation which describes the process of sintering by its main parameters sintering time, sintering temperature and volume contracting. Such equation is called a sintering equation. It also contains some coefficients which characterise the behaviour of the material during the process of sintering. These coefficients have to be determined by experiments. Here we show that some linear regressions will produce wrong coefficients, but multiple regression results in an useful sintering equation. (orig.)

  15. Improvement of mechanical strength of sintered Mo alloyed steel by optimization of sintering and cold-forging processes with densification

    Science.gov (United States)

    Kamakoshi, Y.; Shohji, I.; Inoue, Y.; Fukuda, S.

    2017-10-01

    Powder metallurgy (P/M) materials have been expected to be spread in automotive industry. Generally, since sintered materials using P/M ones contain many pores and voids, mechanical properties of them are inferior to those of conventional wrought materials. To improve mechanical properties of the sintered materials, densification is effective. The aim of this study is to improve mechanical strength of sintered Mo-alloyed steel by optimizing conditions in sintering and cold-forging processes. Mo-alloyed steel powder was compacted. Then, pre-sintering (PS) using a vacuum sintering furnace was conducted. Subsequently, coldforging (CF) by a backward extrusion method was conducted to the pre-sintered specimen. Moreover, the cold-forged specimen was heat treated by carburizing, tempering and quenching (CQT). Afterwards, mechanical properties were investigated. As a result, it was found that the density of the PS specimen is required to be more than 7.4 Mg/m3 to strengthen the specimen by heat treatment after CF. Furthermore, density and the microstructure of the PS specimen are most important factors to make the high density and strength material by CF. At the CF load of 1200 kN, the maximum density ratio reached approximately 99% by the use of the PS specimen with proper density and microstructure. At the CF load of 900 kN, although density ratio was high like more than 97.8%, transverse rupture strength decreased sharply. Since densification caused high shear stress and stress concentration in the surface layer, microcracks occurred by the damages of inter-particle sintered connection of the surface layer. On the contrary, in case of the CF load of 1200 kN, ultra-densification of the surface layer occurred by a sufficient plastic flow. Such sufficient compressed specimens regenerated the sintered connections by high temperature heat treatment and thus the high strength densified material was obtained. These processes can be applicable to near net shape manufacturing

  16. Potential Use of Polyaluminium Chloride and Tobacco Leaf as Coagulant and Coagulant Aid in Post-Treatment of Landfill Leachate

    Directory of Open Access Journals (Sweden)

    Nurfarahim Rusdizal

    2015-12-01

    Full Text Available A study was conducted to treat stabilized leachate by applying polyaluminium chloride (PAC and tobacco leaf extract as a coagulant and coagulant aid. Experimental results indicated that the tobacco leaves were positively charged. The removal rate of the chemical oxygen demand, using 1500 mg/L PAC as a sole coagulant, was approximately 63% and increased to 91% when 1000 mg/L PAC was mixed with 1000 mg/L tobacco leaf. Additionally, 1500 mg/L PAC with 250 - 1000 mg/L tobacco leaf and 54% ammoniacal nitrogen was removed, compared with only 46% reduction using 1500 mg/L with only 46% reduction.

  17. Plutonium Immobilization Project Binder Burnout and Sintering Studies (Milestone 6.6a)

    Energy Technology Data Exchange (ETDEWEB)

    Chandler, G.

    1999-10-28

    The Plutonium Immobilization Team has developed an integrated test program to understand and optimize the controlling variables for the sintering step of the plutonium immobilization process. Sintering is the key process step that controls the product minerology. It is expected that the sintering will be the limiting process step that controls the throughput of the production line. The goal of the current sintering test program is to better understand factors that affect the sintering process.

  18. Plutonium Immobilization Project Binder Burnout and Sintering Studies (Milestone 6.6a)

    International Nuclear Information System (INIS)

    Chandler, G.

    1999-01-01

    The Plutonium Immobilization Team has developed an integrated test program to understand and optimize the controlling variables for the sintering step of the plutonium immobilization process. Sintering is the key process step that controls the product mineralogy. It is expected that the sintering will be the limiting process step that controls the throughput of the production line. The goal of the current sintering test program is to better understand factors that affect the sintering process

  19. Sintering and electrical properties of strontium-doped lanthanum manganite

    Energy Technology Data Exchange (ETDEWEB)

    Tarrago, Diego Pereira; Sousa, Vania Caldas de [Universidade Federal do Rio Grande do Sul (LABIOMAT/PPGEM/UFRGS), Porto Alegre, RS (Brazil). Programa de Pos-Graduacao em Engenharia de Minas, Metalurgica e de Materiais. Lab. de Biomateriais], Email: dptarrago@gmail.com; Moreno Buriel, Berta; Chinarro Martini, Eva; Jurado Egea, Jose Ramon [Consejo Superior de Investigaciones Cientificas (ICV/CSIC), Madrid (Spain). Inst. de Ceramica y Vidrio; Malfatti, Celia de Fraga [Universidade Federal do Rio Grande do Sul (LAPEC/PPGEM/UFRGS), Porto Alegre, RS (Brazil). Programa de Pos-Graduacao em Engenharia de Minas, Metalurgica e de Materiais. Lab. de Pesquisa em Corrosao

    2010-07-01

    Lanthanum strontium manganites (LSM) are potential materials for cathode applications in solid oxide fuel cells (SOFC) due to their good catalytic activity, chemical stability and compatibility with electrolyte materials in high temperatures. The sinterability of single phase La{sub 1-x}Sr{sub x}Mn{sub O3} (x=0.18) perovskite powders and the electrical properties of the resulting samples are analyzed in this study. Using a heating microscope, the powders were pressed and sintered at different pressures and temperatures, resulting in an open porosity of 33.36% when compacted at 125 MPa and sintered at 1200 degree C. Top and cross-section s canning electron microscopy (SEM) micrographs revealed interconnected pores in the sintered body and, hence, a suitable microstructure for the application. The activation energy for conductance was 0.04 eV and the tested LSM bulk started to exhibit adequate electrical properties at about 500 degree C. (author)

  20. Zone refining of sintered, microwave-derived YBCO superconductors

    International Nuclear Information System (INIS)

    Warrier, K.G.K.; Varma, H.K.; Mani, T.V.; Damodaran, A.D.; Balachandran, U.

    1993-07-01

    Post-sintering treatments such as zone melting under thermal gradient has been conducted on sintered YBCO tape cast films. YBCO precursor powder was derived through decomposition of a mixture of nitrates of cations in a microwave oven for ∼4 min. The resulting powder was characterized and made into thin sheets by tape casting and then sintered at 945 C for 5 h. The sintered tapes were subjected to repeated zone refining operations at relatively high speeds of ∼30 mm/h. A microstructure having uniformly oriented grains in the a-b plane throughout the bulk of the sample was obtained by three repeated zone refining operations. Details of precursor preparation, microwave processing and its advantages, zone refining conditions, and microstructural features are presented in this paper

  1. Quartz crystal reinforced quartz glass by spark plasma sintering

    International Nuclear Information System (INIS)

    Torikai, D.; Barazani, B.; Ono, E.; Santos, M.F.M.; Suzuki, C.K.

    2011-01-01

    The Spark Plasma Sintering presents fast processing time when compared to conventional sintering techniques. This allows to control the grain growth during sintering as well as the diffusion rate of a multi-material compounds, and make possible obtainment of functionally graded materials and nanostructured compounds. Powders of high purity silica glass and crystalline silica were sintered in a SPS equipment at temperatures around 1350° C, i.e., above the softening temperature of silica glass and below the melting temperature of quartz crystal. As a result, glass ceramics with pure silica glass matrix reinforced with crystalline alpha-quartz grains were fabricated at almost any desired range of composition, as well as controlled size of the crystalline reinforcement. X-ray diffraction and density measurements showed the possibility to manufacture a well controlled density and crystallinity glass-ceramic materials. (author)

  2. Electric Field-Assisted Pressureless Sintering of Ceramic Protonic Conductors

    DEFF Research Database (Denmark)

    Muccillo, R.; Esposito, Vincenzo; de Florio, D. Z.

    2017-01-01

    Gadolinium, yttrium and samarium-doped barium cerate pressed pellets were submitted to flash sintering experiments isothermally in the temperature range 800-1300oC under 200 V cm-1 electric field. The pellets were positioned inside a dilatometer furnace with Pt-Ir electrodes connected either...... to a power supply or to an impedance analyzer to evaluate the bulk and the grain boundary contributions to the electrical resistivity. Near full density was achieved in the sintered samples. The combined results of dilatometry and impedance measurements in conventionally and flash sintered specimens show...... substantial improvement of the electrical conductivity. Joule heating is assumed to be the primary effect for sintering. Improved grain-to-grain contact and the removal of depleted chemical species due to Joule heating at the space charge region are proposed, respectively, as the reasons for the decrease...

  3. Onset conditions for flash sintering of UO2

    Science.gov (United States)

    Raftery, Alicia M.; Pereira da Silva, João Gustavo; Byler, Darrin D.; Andersson, David A.; Uberuaga, Blas P.; Stanek, Christopher R.; McClellan, Kenneth J.

    2017-09-01

    In this work, flash sintering was demonstrated on stoichiometric and non-stoichiometric uranium dioxide pellets at temperatures ranging from room temperature (26 °C) up to 600 °C . The onset conditions for flash sintering were determined for three stoichiometries (UO2.00, UO2.08, and UO2.16) and analyzed against an established thermal runaway model. The presence of excess oxygen was found to enhance the flash sintering onset behavior of uranium dioxide, lowering the field required to flash and shortening the time required for a flash to occur. The results from this study highlight the effect of stoichiometry on the flash sintering behavior of uranium dioxide and will serve as the foundation for future studies on this material.

  4. Foam glass obtained through high-pressure sintering

    DEFF Research Database (Denmark)

    Østergaard, Martin Bonderup; Petersen, Rasmus Rosenlund; König, Jakob

    2018-01-01

    are subjected to a second heat treatment above the glass transition temperature at atmospheric pressure. This heat treatment causes expansion of the pores due to high internal gas pressure. We found that the foaming ability strongly depends on the gas pressure applied during sintering, and on the kinetic......Foam glasses are usually prepared through a chemical approach, that is, by mixing glass powder with foaming agents, and heating the mixture to a temperature above the softening point (106.6 Pa s) of the glass. The foaming agents release gas, enabling expansion of the sintered glass. Here, we use...... a physical foaming approach to prepare foam glass. First, closed pores filled with inert gases (He, Ar, or N2) are physically introduced into a glass body by sintering cathode ray tube (CRT) panel glass powder at high gas pressure (5‐25 MPa) at 640°C and, then cooled to room temperature. The sintered bodies...

  5. Efficient Radiation Shielding Through Direct Metal Laser Sintering

    Data.gov (United States)

    National Aeronautics and Space Administration — We have developed a method for efficient component-level radiation shielding that can be printed by direct metal laser sintering (DMLS) from files generated by the...

  6. Non-pressurized sintered silicon carbide with titanium carbide reinforcement

    International Nuclear Information System (INIS)

    Adler, J.

    1992-01-01

    A non-pressurized compression of SiC-TiC composite materials can be achieved via liquid phase sintering by the application of oxidic additives. Materials with TiC proportions up to 40% by volume of TiC and densities of 97 to 98% TD were produced at sintering temperatures around 1875 C. With SiC sintered in the liquid phase an increase of toughness at fracture of 80% compared with conventionally non-pressurized sintered SiC was achieved with B/C additive. No further increase could be achieved by the addition of TiC particles. However, the oxidation resistance at 1200 C was worsened. (orig.) [de

  7. Pressureless sintering behavior of injection molded alumina ceramics

    Directory of Open Access Journals (Sweden)

    Liu W.

    2014-01-01

    Full Text Available The pressureless sintering behaviors of two widely used submicron alumina (MgOdoped and undoped with different solid loadings produced by injection molding have been studied systematically. Regardless of the sinterability of different powders depending on their inherent properties, solid loading plays a critical role on the sintering behavior of injection molded alumina, which greatly determines the densification and grain size, and leads to its full densification at low temperatures. As compared to the MgO-doped alumina powder, the undoped specimens exhibit a higher sinterability for its smaller particle size and larger surface area. While full densification could be achieved for MgO-doped powders with only a lower solid loading, due to the fact that MgO addition can reduce the detrimental effect of the large pore space on the pore-boundary separation.

  8. Modeling constrained sintering of bi-layered tubular structures

    DEFF Research Database (Denmark)

    Tadesse Molla, Tesfaye; Kothanda Ramachandran, Dhavanesan; Ni, De Wei

    2015-01-01

    Constrained sintering of tubular bi-layered structures is being used in the development of various technologies. Densification mismatch between the layers making the tubular bi-layer can generate stresses, which may create processing defects. An analytical model is presented to describe...... the densification and stress developments during sintering of tubular bi-layered samples. The correspondence between linear elastic and linear viscous theories is used as a basis for derivation of the model. The developed model is first verified by finite element simulation for sintering of tubular bi-layer system....... Furthermore, the model is validated using densification results from sintering of bi-layered tubular ceramic oxygen membrane based on porous MgO and Ce0.9Gd0.1O1.95-d layers. Model input parameters, such as the shrinkage kinetics and viscous parameters are obtained experimentally using optical dilatometry...

  9. Verification of the Skorohod-Olevsky Viscous Sintering (SOVS) Model

    Energy Technology Data Exchange (ETDEWEB)

    Lester, Brian T. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2017-11-16

    Sintering refers to a manufacturing process through which mechanically pressed bodies of ceramic (and sometimes metal) powders are heated to drive densification thereby removing the inherit porosity of green bodies. As the body densifies through the sintering process, the ensuing material flow leads to macroscopic deformations of the specimen and as such the final configuration differs form the initial. Therefore, as with any manufacturing step, there is substantial interest in understanding and being able to model the sintering process to predict deformation and residual stress. Efforts in this regard have been pursued for face seals, gear wheels, and consumer products like wash-basins. To understand the sintering process, a variety of modeling approaches have been pursued at different scales.

  10. Effects of coagulating enzyme types (commercial calf rennet ...

    African Journals Online (AJOL)

    Effects of coagulating enzyme types (commercial calf rennet, Aspergillus niger var. awamori as recombinant chymosin and rhizomucor miehei as microbial rennet) on the chemical and sensory characteristics of white pickled cheese.

  11. Coagulation profile in patients undergoing video-assisted thoracoscopic lobectomy

    DEFF Research Database (Denmark)

    Christensen, Thomas Decker; Vad, Henrik; Pedersen, Søren

    2017-01-01

    Background: Knowledge about the impact of Low-Molecular-Weight Heparin (LMWH) on the coagulation system in patients undergoing minimal invasive lung cancer surgery is sparse. The aim of this study was to assess the effect of LMWH on the coagulation system in patients undergoing Video......-Assisted Thoracoscopic Surgery (VATS) lobectomy for primary lung cancer. Methods: Sixty-three patients diagnosed with primary lung cancer undergoing VATS lobectomy were randomized to either subcutaneous injection with dalteparin (Fragmin®) 5000 IE once daily or no intervention. Coagulation was assessed pre-, peri......-, and the first two days postoperatively by standard coagulation blood test, thromboelastometry (ROTEM®) and thrombin generation. Results: Patients undergoing potential curative surgery for lung cancer were not hypercoagulable preoperatively. There was no statistically significant difference in the majority...

  12. Effects of a polymeric organic coagulant for industrial mineral oil ...

    African Journals Online (AJOL)

    A50, its efficiency was evaluated to serve as an alternative coagulant for the pretreatment of the MOW. The removal of chemical oxidation demand (COD), soap oil and grease (SOG), total suspended solids (TSS) and turbidity from the MOW ...

  13. Bio-responsive polymer hydrogels homeostatically regulate blood coagulation.

    Science.gov (United States)

    Maitz, Manfred F; Freudenberg, Uwe; Tsurkan, Mikhail V; Fischer, Marion; Beyrich, Theresa; Werner, Carsten

    2013-01-01

    Bio-responsive polymer architectures can empower medical therapies by engaging molecular feedback-response mechanisms resembling the homeostatic adaptation of living tissues to varying environmental constraints. Here we show that a blood coagulation-responsive hydrogel system can deliver heparin in amounts triggered by the environmental levels of thrombin, the key enzyme of the coagulation cascade, which--in turn--becomes inactivated due to released heparin. The bio-responsive hydrogel quantitatively quenches blood coagulation over several hours in the presence of pro-coagulant stimuli and during repeated incubation with fresh, non-anticoagulated blood. These features enable the introduced material to provide sustainable, autoregulated anticoagulation, addressing a key challenge of many medical therapies. Beyond that, the explored concept may facilitate the development of materials that allow the effective and controlled application of drugs and biomolecules.

  14. Does whole blood coagulation analysis reflect developmental haemostasis?

    DEFF Research Database (Denmark)

    Ravn, Hanne Berg; Andreasen, Jo Bnding; Hvas, Anne-Mette

    2017-01-01

    : Developmental haemostasis has been well documented over the last 3 decades and age-dependent reference ranges have been reported for a number of plasmatic coagulation parameters. With the increasing use of whole blood point-of-care tests like rotational thromboelastometry (ROTEM) and platelet...... function tests, an evaluation of age-dependent changes is warranted for these tests as well. We obtained blood samples from 149 children, aged 1 day to 5.9 years, and analysed conventional plasmatic coagulation tests, including activated partial prothrombin time, prothrombin time, and fibrinogen...... (functional). Whole blood samples were analysed using ROTEM to assess overall coagulation capacity and Multiplate analyzer to evaluate platelet aggregation. Age-dependent changes were analysed for all variables. We found age-dependent differences in all conventional coagulation tests (all P values

  15. Dynamic Modeling of the Human Coagulation Cascade Using Reduced Order Effective Kinetic Models (Open Access)

    Science.gov (United States)

    2015-03-16

    with logical rules to simulate an archetype biochemical network, the human coagulation cascade. The model consisted of five differential equations...coagulation system. Coagulation is an archetype proteolytic cascade involving both positive and negative feedback [10–12]. Coagulation is mediated by a...purely ODE models in the literature . We estimated the model parameters from in vitro extrinsic coagulation data sets, in the presence of ATIII, with and

  16. Ash chemistry and sintering, verification of the mechanisms

    Energy Technology Data Exchange (ETDEWEB)

    Hupa, M.; Skrifvars, B.J. [Aabo Akademi, Turku (Finland)

    1996-12-01

    In this project four sintering mechanisms have been studied, i.e., partial melting with a viscous liquid, partial melting with a non-viscous liquid, chemical reaction sintering and solid state sintering. The work has aimed at improving the understanding of ash sintering mechanisms and quantifying their role in combustion and gasification. The work has been oriented in particular on the understanding of biomass ash behavior. The work has not directly focused on any specific technical application. However, results can also be applied on other fuels such as brown coal, petroleum coke, black liquor and different types of wastes (PDF, RDF, MSW). In one part of study the melting behavior was calculated for ten biomass ashes and compared with lab measurements of sintering tendencies. The comparison showed that the T{sub 15} temperatures, i.e. those temperatures at which the ashes contained 15 % molten phase, correlated fairly well with the temperature at which the sintering measurements detected sintering. This suggests that partial melting can be predicted fairly accurate for some ashes already with the today existing thermodynamic calculation routines. In some cases, however the melting calculations did not correlate with the detected sintering temperatures. In a second part detailed measurements on ash behavior was conducted both in a semi full scale CFB and a lab scale FBC. Ashes and deposits were collected and analyzed in several different ways. These analyses show that the ash chemistry shifts radically when the fuel is shifted. Fuels with silicate based ashes behaved totally different than those with an oxide or salt based ash. The chemistry was also affected by fuel blending. The ultimate goal has been to be able to predict the ash thermal behavior during biomass thermal conversion, using the fuel and ash elemental analyses and a few operational key parameters as the only input data. This goal has not yet today been achieved. (author)

  17. Low temperature sintering of fluorapatite glass-ceramics.

    Science.gov (United States)

    Denry, Isabelle; Holloway, Julie A

    2014-02-01

    Fluorapatite glass-ceramics have been shown to be excellent candidates as scaffold materials for bone grafts, however, scaffold production by sintering is hindered by concurrent crystallization of the glass. Objective, our goal was to investigate the effect of Ca/Al ratio on the sintering behavior of Nb-doped fluorapatite-based glasses in the SiO2-Al2O3-P2O5-MgO-Na2O-K2O-CaO-CaF2 system. Methods, glass compositions with Ca/Al ratio of 1 (A), 2 (B), 4 (C) and 19 (D) were prepared by twice melting at 1525°C for 3h. Glasses were either cast as cylindrical ingots or ground into powders. Disk-shaped specimens were prepared by either sectioning from the ingots or powder-compacting in a mold, followed by heat treatment at temperatures ranging between 700 and 1050°C for 1h. The density was measured on both sintered specimens and heat treated discs as controls. The degree of sintering was determined from these measurements. Results and Significance XRD showed that fluorapatite crystallized in all glass-ceramics. A high degree of sintering was achieved at 775°C for glass-ceramic D (98.99±0.04%), and 900°C for glass-ceramic C (91.31±0.10). Glass-ceramics A or B were only partially sintered at 1000°C (63.6±0.8% and 74.1±1.5%, respectively). SEM revealed a unique microstructure of micron-sized spherulitic fluorapatite crystals in glass-ceramics C and D. Increasing the Ca/Al ratio promoted low temperature sintering of fluorapatite glass-ceramics, which are traditionally difficult to sinter. Copyright © 2013 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

  18. Process for preparing sintered uranium dioxide nuclear fuel

    International Nuclear Information System (INIS)

    Carter, R.E.

    1975-01-01

    Uranium dioxide is prepared for use as fuel in nuclear reactors by sintering it to the desired density at a temperature less than 1300 0 C in a chemically controlled gas atmosphere comprised of at least two gases which in equilibrium provide an oxygen partial pressure sufficient to maintain the uranium dioxide composition at an oxygen/uranium ratio of at least 2.005 at the sintering temperature. 7 Claims, No Drawings

  19. Corrosion Properties of Sintered and Wrought Stainless Seel

    DEFF Research Database (Denmark)

    Mathiesen, Troels; Maahn, Ernst Emanuel

    1997-01-01

    The corrosion properties of a range of stainless steels produced by powder metallurgy (PM) are compared with wrought AISI304 and AISI316 Steel. Characterisation of the passivation properties in 0.5M H2SO4 and pittingresistance in 0.3% chloride solution by polarisation show properties...... of the sintered PM150 that are comparable or better than those of wrought 316 steel depending on the applied sintering technique....

  20. Low temperature sintering of fluorapatite glass-ceramics

    Science.gov (United States)

    Denry, Isabelle; Holloway, Julie A.

    2014-01-01

    Fluorapatite glass-ceramics have been shown to be excellent candidates as scaffold materials for bone grafts, however, scaffold production by sintering is hindered by concurrent crystallization of the glass. Our goal was to investigate the effect of Ca/Al ratio on the sintering behavior of Nb-doped fluorapatite-based glasses in the SiO2-Al2O3-P2O5-MgO-Na2O-K2O-CaO-CaF2 system. Glass compositions with Ca/Al ratio of 1 (A), 2 (B), 4 (C) and 19 (D) were prepared by twice melting at 1525°C for 3h. Glasses were either cast as cylindrical ingots or ground into powders. Disc-shaped specimens were prepared by either sectioning from the ingots or powder-compacting in a mold, followed by heat treatment at temperatures ranging between 700 and 1050°C for 1h. The density was measured on both sintered specimens and heat treated discs as controls. The degree of sintering was determined from these measurements. XRD showed that fluorapatite crystallized in all glass-ceramics. A high degree of sintering was achieved at 775°C for glass-ceramic D (98.99±0.04%), and 900°C for glass-ceramic C (91.31±0.10). Glass-ceramics A or B were only partially sintered at 1000°C (63.6±0.8% and 74.1±1.5%, respectively). SEM revealed a unique microstructure of micron-sized spherulitic fluorapatite crystals in glass-ceramics C and D. Increasing the Ca/Al ratio promoted low temperature sintering of fluorapatite glass-ceramics, which are traditionally difficult to sinter. PMID:24252652

  1. Properties of Bulk Sintered Silver As a Function of Porosity

    Energy Technology Data Exchange (ETDEWEB)

    Wereszczak, Andrew A [ORNL; Vuono, Daniel J [ORNL; Wang, Hsin [ORNL; Ferber, Mattison K [ORNL; Liang, Zhenxian [ORNL

    2012-06-01

    This report summarizes a study where various properties of bulk-sintered silver were investigated over a range of porosity. This work was conducted within the National Transportation Research Center's Power Device Packaging project that is part of the DOE Vehicle Technologies Advanced Power Electronics and Electric Motors Program. Sintered silver, as an interconnect material in power electronics, inherently has porosity in its produced structure because of the way it is made. Therefore, interest existed in this study to examine if that porosity affected electrical properties, thermal properties, and mechanical properties because any dependencies could affect the intended function (e.g., thermal transfer, mechanical stress relief, etc.) or reliability of that interconnect layer and alter how its performance is modeled. Disks of bulk-sintered silver were fabricated using different starting silver pastes and different sintering conditions to promote different amounts of porosity. Test coupons were harvested out of the disks to measure electrical resistivity and electrical conductivity, thermal conductivity, coefficient of thermal expansion, elastic modulus, Poisson's ratio, and yield stress. The authors fully recognize that the microstructure of processed bulk silver coupons may indeed not be identical to the microstructure produced in thin (20-50 microns) layers of sintered silver. However, measuring these same properties with such a thin actual structure is very difficult, requires very specialized specimen preparation and unique testing instrumentation, is expensive, and has experimental shortfalls of its own, so the authors concluded that the herein measured responses using processed bulk sintered silver coupons would be sufficient to determine acceptable values of those properties. Almost all the investigated properties of bulk sintered silver changed with porosity content within a range of 3-38% porosity. Electrical resistivity, electrical conductivity

  2. Impact strength of sintered astaloy CrM powders

    International Nuclear Information System (INIS)

    Kazior, J.; Ploszczak, J.; Nykiel, M.; Pieczonka, T.

    2003-01-01

    In this paper results of a series of impact tests on sintered Astaloy CrM powders alloys modified by boron are presented and discussed. Boron in different forms, i.e. as elemental boron powder, boron carbide B 4 C powder or mixture of boron and carbon elemental powders, was used in different weight percentage to activate sintering of Astaloy CrM powder and to increase hardenability, with aim of increasing impact strength in view of structural applications. (author)

  3. [Modification of plasma blood coagulation factor activity by physical stress].

    Science.gov (United States)

    Lutze, G; Buhl, H; Häcker, R; Socha, C; Socha, U; Urbahn, H

    1986-09-15

    The influence of physical stress (bicycle ergometer and track) on 13 parameters of the plasmatic coagulation system was investigated in trained and untrained test persons. Shortenings of the coagulation times as well as distinct increases of the activity or concentration were observed in the partial thromboplastin time (PTT), the factor VIII activity (VIII:C) and the factor VIII-associated antigen (VIIIR:Ag). The results are discussed with regard to their causes and their clinical importance.

  4. Optimizing centrifugation of coagulation samples in laboratory automation.

    Science.gov (United States)

    Suchsland, Juliane; Friedrich, Nele; Grotevendt, Anne; Kallner, Anders; Lüdemann, Jan; Nauck, Matthias; Petersmann, Astrid

    2014-08-01

    High acceleration centrifugation conditions are used in laboratory automation systems to reduce the turnaround time (TAT) of clinical chemistry samples, but not of coagulation samples. This often requires separate sample flows. The CLSI guideline and manufacturers recommendations for coagulation assays aim at reducing platelet counts. For measurement of prothrombin time (PT) and activated partial thromboplastin time (APTT) platelet counts (Plt) below 200×10(9)/L are recommended. Other coagulation assays may require even lower platelet counts, e.g., less than 10 × 10(9)/L. Unifying centrifugation conditions can facilitate the integration of coagulation samples in the overall workflow of a laboratory automation system. We evaluated centrifugation conditions of coagulation samples by using high acceleration centrifugation conditions (5 min; 3280×g) in a single and two consecutive runs. RESULTS of coagulation assays [PT, APTT, coagulation factor VIII (F. VIII) and protein S] and platelet counts were compared after the first and second centrifugation. Platelet counts below 200×10(9)/L were obtained in all samples after the first centrifugation and less than 10 × 10(9)/L was obtained in 73% of the samples after a second centrifugation. Passing-Bablok regression analyses showed an equal performance of PT, APTT and F. VIII after first and second centrifugation whereas protein S measurements require a second centrifugation. Coagulation samples can be integrated into the workflow of a laboratory automation system using high acceleration centrifugation. A single centrifugation was sufficient for PT, APTT and F. VIII whereas two successive centrifugations appear to be sufficient for protein S activity.

  5. Colloids removal from water resources using natural coagulant: Acacia auriculiformis

    Science.gov (United States)

    Abdullah, M.; Roslan, A.; Kamarulzaman, M. F. H.; Erat, M. M.

    2017-09-01

    All waters, especially surface waters contain dissolved, suspended particles and/or inorganic matter, as well as several biological organisms, such as bacteria, algae or viruses. This material must be removed because it can affect the water quality that can cause turbidity and colour. The objective of this study is to develop water treatment process from Seri Alam (Johor, Malaysia) lake water resources by using natural coagulant Acacia auriculiformis pods through a jar test experiment. Jar test is designed to show the effectiveness of the water treatment. This process is a laboratory procedure that will simulate coagulation/flocculation with several parameters selected namely contact time, coagulant dosage and agitation speed. The most optimum percentage of colloids removal for each parameter is determined at 0.2 g, 90 min and 80 rpm. FESEM (Field-emission Scanning Electron Microscope) observed the small structures of final floc particles for optimum parameter in this study to show that the colloids coagulated the coagulant. All result showed that the Acacia auriculiformis pods can be a very efficient coagulant in removing colloids from water.

  6. A Pontential Agriculture Waste Material as Coagulant Aid: Cassava Peel

    Science.gov (United States)

    Othman, N.; Abd-Rahim, N.-S.; Tuan-Besar, S.-N.-F.; Mohd-Asharuddin, S.; Kumar, V.

    2018-02-01

    All A large amount of cassava peel waste is generated annually by small and medium scale industries. This has led to a new policy of complete utilization of raw materials so that there will be little or no residue left that could pose pollution problems. Conversion of these by-products into a material that poses an ability to remove toxic pollutant would increase the market value and ultimately benefits the producers. This study investigated the characteristics of cassava peel as a coagulant aid material and optimization process using the cassava peel was explored through coagulation and flocculation. This research had highlighted that the Cassava peels contain sugars in the form of polysaccharides such as starch and holocellulose. The FTIR results revealed that amino acids containing abundant of carboxyl, hydroxyl and amino groups which has significant capabilities in removing pollutants. Whereas analysis by XRF spectrometry indicated that the CP samples contain Fe2O3 and Al2O3 which might contribute to its coagulation ability. The optimum condition allowed Cassava peel and alum removed high turbidity up to 90. This natural coagulant from cassava peel is found to be an alternative coagulant aid to reduce the usage of chemical coagulants

  7. Adaptive force sonorheometry for assessment of whole blood coagulation.

    Science.gov (United States)

    Mauldin, F William; Viola, Francesco; Hamer, Theresa C; Ahmed, Eman M; Crawford, Shawna B; Haverstick, Doris M; Lawrence, Michael B; Walker, William F

    2010-05-02

    Viscoelastic diagnostics that monitor the hemostatic function of whole blood (WB), such as thromboelastography, have been developed with demonstrated clinical utility. By measuring the cumulative effects of all components of hemostasis, viscoelastic diagnostics have circumvented many of the challenges associated with more common tests of blood coagulation. We describe a new technology, called sonorheometry, that adaptively applies acoustic radiation force to assess coagulation function in WB. The repeatability (precision) of coagulation parameters was assessed using citrated WB samples. A reference range of coagulation parameters, along with corresponding measurements from prothrombin time (PT) and partial thromboplastin time (PTT), were obtained from WB samples of 20 healthy volunteers. In another study, sonorheometry monitored anticoagulation with heparin (0-5 IU/ml) and reversal from varied dosages of protamine (0-10 IU/ml) in heparinized WB (2 IU/ml). Sonorheometry exhibited low CVs for parameters: clot initiation time (TC1), 0.98 for all coagulation parameters. We observed maximum reversal of heparin anticoagulation at protamine to heparin ratios of 1.4:1 from TC1 (P=0.6) and 1.2:1 from theta (P=0.55). Sonorheometry is a non-contact method for precise assessment of WB coagulation. Copyright 2010 Elsevier B.V. All rights reserved.

  8. Enhanced Sintering of Boron Carbide-Silicon Composites by Silicon

    Science.gov (United States)

    Zeng, Xiaojun; Liu, Weiliang

    2016-11-01

    Boron carbide (B4C)-silicon (Si) composites have been prepared by aqueous tape casting, laminating, and spark plasma sintering (SPS). The influences of silicon (Si) content on the phases, microstructure, sintering properties, and mechanical properties of the obtained B4C-Si composites are studied. The results indicate that the addition of Si powder can act as a sintering aid and contribute to the sintering densification. The addition of Si powder can also act as a second phase and contribute to the toughening for composites. The relative density of B4C-Si composites samples with adding 10 wt.% Si powder prepared by SPS at 1600 °C and 50 MPa for 8 min is up to 98.3%. The bending strength, fracture toughness, and Vickers hardness of the sintered samples are 518.5 MPa, 5.87 MPa m1/2, and 38.9 GPa, respectively. The testing temperature-dependent high-temperature bending strength and fracture toughness can reach a maximum value at 1350 °C. The B4C-Si composites prepared at 1600, 1650, and 1700 °C have good high-temperature mechanical properties. This paper provides a facile low-temperature sintering route for B4C ceramics with improved properties.

  9. Bending Behavior of Porous Sintered Stainless Steel Fiber Honeycombs

    Science.gov (United States)

    Zou, Shuiping; Wan, Zhenping; Lu, Longsheng; Tang, Yong

    2017-02-01

    A novel porous honeycomb-type substrate has been developed using solid-state sintering stainless steel fibers. The porous sintered stainless steel fiber honeycombs (PSSSFH) are composed of a skeleton of sintered stainless steel fibers, three-dimensionally interconnected porous structures and multiple parallel microchannels. The bending behavior of the PSSSFH is investigated using three-point bending tests. Four stages, including an elastic stage, a yielding stage with a plateau, a hardening stage and a failure stage, are observed during the bending process of the PSSSFH. In the initial yielding stage, the bending forces increase slowly with displacement increasing, and then a yielding plateau follows, which is unique compared with other porous materials. Moreover, the structure parameters of the PSSSFH are varied to investigate the influence on the bending strength. It is determined that the multiple parallel microchannels can enhance the bending strength of porous stainless steel fiber sintered substrates (PSSFSS) and do not influence the variation trend of bending strength of PSSFSS with porosity increasing. The open ratio is conducive to increasing the bending strength, and the microchannel diameters ranging from 0.5 mm to 1.5 mm have little influence on the bending strength. In addition, both the increasing of sintering temperature and sintering time can strengthen the PSSSFH.

  10. Industrial Sintering of Uranium Oxide in a Continuous Furnace

    International Nuclear Information System (INIS)

    Hauser, R.; Porneuf, A.

    1963-01-01

    Under a USAEC-EURATOM research contract, CICAF (Compagnie industrielle de combustibles atomiques frittes) was asked by the French Atomic Energy Commission to design and construct a continuous furnace sintering under a reducing atmosphere at high temperature. The characteristic features of the furnace are automatic operation, rigorous control of presintering and sintering atmospheres, flexibility of temperature regulation so that the thermal cycle can be adjusted to the product to be sintered and high output (5 t of uranium oxide per month). It can operate continuously up to 1700 deg. C, the presintering taking place at a lower temperature (800 deg. C) in a preliminary furnace which forms an integral part of the whole. The sintering atmosphere is cracked ammonia or pure hydrogen; the presintering atmosphere is a mixture o f about 10% hydrogen and 90% nitrogen. The sintered pellets densify to above 97% of theoretical density, with a total dispersion of less than 1%. Structurally, they are equi-axed grains of about 10μm. It was established that the stoichiometric variation of the uranium oxide sintered in a continuous furnace was less than 0.005. (author) [fr

  11. Manufacture of sintered bricks of high density from beryllium oxide

    International Nuclear Information System (INIS)

    Pointud, R.; Rispal, Ch.; Le Garec, M.

    1959-01-01

    Beryllium oxide bricks of nuclear purity 100 x 100 x 50 and 100 x 100 x 100 mm of very high density (between 2.85 and 3.00) are manufactured by sintering under pressure in graphite moulds at temperatures between 1,750 and 1,850 deg. C, and under a pressure of 150 kg/cm 2 . The physico-chemical state of the saw material is of considerable importance with regard to the success of the sintering operation. In addition, a study of the sintering of a BeO mixture with 3 to 5 per cent of boron introduced in the form of boric acid, boron carbide or elementary boron shows that high densities can only be obtained by sintering under pressure. For technical reasons of manufacture, only the mixture based on boron carbide is used. The sintering is carried out in graphite moulds at 1500 deg. C under 150 kg/cm 2 pressure, and bricks can be obtained with density between 2,85 and 2,90. Laboratory studies and the industrial manufacture of various sinters are described in detail. (author) [fr

  12. Uniaxial ratcheting behavior of sintered nanosilver joint for electronic packaging

    International Nuclear Information System (INIS)

    Chen, Gang; Yu, Lin; Mei, Yunhui; Li, Xin; Chen, Xu; Lu, Guo-Quan

    2014-01-01

    Uniaxial ratcheting behavior and the fatigue life of sintered nanosilver joint were investigated at room temperature. All tests were carried out under stress-controlled mode. Force–displacement data were recorded during the entire fatigue lifespan by a non-contact displacement detecting system. Effects of stress amplitude, mean stress, stress rate, and stress ratio on the uniaxial ratcheting behavior of the sintered nanosilver joint were discussed. Stress-life (S–N) curves of the sintered joints were also obtained. The Smith–Watson–Topper (SWT) model, the Gerber model and the modified Goodman model, all of which took effect of mean stress into consideration, were compared for predicting the fatigue life of the sintered joint. Both the ratcheting strain and its rate increased with increasing stress amplitude or mean stress. The increase in stress amplitude and mean stress both reduced the fatigue life of the sintered joint, while the fatigue life prolonged with the increase in stress rate and stress ratio. The modified Goodman model predicted the fatigue life of the sintered joints well

  13. Monitoring soft tissue coagulation by optical spectroscopy

    Science.gov (United States)

    Lihachev, A.; Lihacova, I.; Heinrichs, H.; Spigulis, J.; Trebst, T.; Wehner, M.

    2017-12-01

    Laser tissue welding (LTW) or laser tissue soldering (LTS) is investigated since many years for treatment of incisions, wound closure and anastomosis of vessels [1, 2]. Depending on the process, a certain temperature in the range between 65 °C to 85 °C must be reached and held for a few seconds. Care has to be taken not to overheat the tissue, otherwise necrosis or tissue carbonization may occur and will impair wound healing. Usually the temperature is monitored during the process to control the laser power [3]. This requires either bulky equipment or expensive and fragile infrared fibers to feed the temperature signal to an infrared detector. Alternatively, changes in tissue morphology can be directly observed by analysis of spectral reflectance. We investigate spectral changes in the range between 400 nm to 900 nm wavelength. Characteristic spectral changes occur when the temperature of tissue samples increase above 70 °C which is a typical setpoint value for temperature control of coagulation. We conclude that simple spectroscopy in the visible range can provide valuable information during LTS and LTW and probably replace the delicate measurement of temperature. A major advantage is that optical measurements can be performed using standard optical fibers and can be easily integrated into a surgical tool.

  14. Effect of sintering temperature on optical properties and microstructure of translucent zirconia prepared by high-pressure spark plasma sintering

    Directory of Open Access Journals (Sweden)

    Haibin Zhang, Byung-Nam Kim, Koji Morita, Hidehiro Yoshida Keijiro Hiraga and Yoshio Sakka

    2011-01-01

    Full Text Available Aiming to characterize the effect of sintering temperature on transparency of zirconia, we have evaluated the optical properties and microstructure of translucent cubic zirconia prepared by high-pressure spark plasma sintering (SPS at 1000–1200 circleC. Color centers (oxygen vacancies with trapped electrons and residual pores were primary defects in the samples. In SPS samples, the total forward transmittance and in-line transmittance are mainly affected by color centers with a limited contribution from residual pores; in contrast, the changes in reflectance are only related to the porosity. The amounts of color centers and residual pores increase with sintering temperature that reduces the total forward and in-line transmittance of the as-sintered zirconia. Annealing in oxidizing atmosphere improves the total forward and in-line transmittance. During the annealing, the concentration of color centers decreases but the porosity increases.

  15. Effect Of Compaction Pressure And Sintering Temperature On The Liquid Phase Sintering Behavior Of Al-Cu-Zn Alloy

    Directory of Open Access Journals (Sweden)

    Lee S.H.

    2015-06-01

    Full Text Available The liquid phase sintering characteristics of Al-Cu-Zn alloy were investigated with respect to various powder metallurgy processing conditions. Powders of each alloying elements were blended to form Al-6Cu-5Zn composition and compacted with pressures of 200, 400, and 600 MPa. The sintering process was performed at various temperatures of 410, 560, and 615°C in N2 gas atmosphere. Density and micro-Vickers hardness measurements were conducted at different processing stages, and transverse rupture strength of sintered materials was examined for each condition, respectively. The microstructure was characterized using optical microscope and scanning electron microscopy. The effect of Zn addition on the liquid phase sintering behavior during P/M process of the Al-Cu-Zn alloy was also discussed in detail.

  16. An experimental study of factors affecting the selective inhibition of sintering process

    Science.gov (United States)

    Asiabanpour, Bahram

    Selective Inhibition of Sintering (SIS) is a new rapid prototyping method that builds parts in a layer-by-layer fabrication basis. SIS works by joining powder particles through sintering in the part's body, and by sintering inhibition of some selected powder areas. The objective of this research has been to improve the new SIS process, which has been invented at USC. The process improvement is based on statistical design of experiments. To conduct the needed experiments a working machine and related path generator software were needed. The machine and its control software were made available prior to this research. The path generator algorithms and software had to be created. This program should obtain model geometry data from a CAD file and generate an appropriate path file for the printer nozzle. Also, the program should generate a simulation file for path file inspection using virtual prototyping. The activities related to path generator constitute the first part of this research, which has resulted in an efficient path generator. In addition, to reach an acceptable level of accuracy, strength, and surface quality in the fabricated parts, all effective factors in the SIS process should be identified and controlled. Simultaneous analytical and experimental studies were conducted to recognize effective factors and to control the SIS process. Also, it was known that polystyrene was the most appropriate polymer powder and saturated potassium iodide was the most effective inhibitor among the available candidate materials. In addition, statistical tools were applied to improve the desirable properties of the parts fabricated by the SIS process. An investigation of part strength was conducted using the Response Surface Methodology (RSM) and a region of acceptable operating conditions for the part strength was found. Then, through analysis of the experimental results, the impact of the factors on the final part surface quality and dimensional accuracy was modeled. After

  17. Alginate microbeads are coagulation compatible, while alginate microcapsules activate coagulation secondary to complement or directly through FXII.

    Science.gov (United States)

    Gravastrand, Caroline; Hamad, Shamal; Fure, Hilde; Steinkjer, Bjørg; Ryan, Liv; Oberholzer, Josè; Lambris, John D; Lacík, Igor; Mollnes, Tom Eirik; Espevik, Terje; Brekke, Ole-Lars; Rokstad, Anne Mari

    2017-08-01

    Alginate microspheres are presently under evaluation for future cell-based therapy. Their ability to induce harmful host reactions needs to be identified for developing the most suitable devices and efficient prevention strategies. We used a lepirudin based human whole blood model to investigate the coagulation potentials of alginate-based microspheres: alginate microbeads (Ca/Ba Beads), alginate poly-l-lysine microcapsules (APA and AP microcapsules) and sodium alginate-sodium cellulose sulfate-poly(methylene-co-cyanoguanidine) microcapsules (PMCG microcapsules). Coagulation activation measured by prothrombin fragments 1+2 (PTF1.2) was rapidly and markedly induced by the PMCG microcapsules, delayed and lower induced by the APA and AP microcapsules, and not induced by the Ca/Ba Beads. Monocytes tissue factor (TF) expression was similarly activated by the microcapsules, whereas not by the Ca/Ba Beads. PMCG microcapsules-induced PTF1.2 was abolished by FXII inhibition (corn trypsin inhibitor), thus pointing to activation through the contact pathway. PTF1.2 induced by the AP and APA microcapsules was inhibited by anti-TF antibody, pointing to a TF driven coagulation. The TF induced coagulation was inhibited by the complement inhibitors compstatin (C3 inhibition) and eculizumab (C5 inhibition), revealing a complement-coagulation cross-talk. This is the first study on the coagulation potentials of alginate microspheres, and identifies differences in activation potential, pathways and possible intervention points. Alginate microcapsules are prospective candidate materials for cell encapsulation therapy. The material surface must be free of host cell adhesion to ensure free diffusion of nutrition and oxygen to the encapsulated cells. Coagulation activation is one gateway to cellular overgrowth through deposition of fibrin. Herein we used a physiologically relevant whole blood model to investigate the coagulation potential of alginate microcapsules and microbeads. The

  18. Thermal Analysis of Sintered Silver Nanoparticles Film

    Directory of Open Access Journals (Sweden)

    M. Keikhaie

    2014-07-01

    Full Text Available Thin bonded films have many applications in antireflection and reflection coating, insulating and conducting films and semiconductor industries. Thermal conductivity is one of the most important parameter for power packaging since the thermal resistance of the interconnections is directly related to the heat removal capability and thermal management of the power package. The defects in materials play very important role on the effective thermal conductivity. In this paper, finite element method (FEM was utilized to simulate the effect of pores on the effective thermal conductivity of sintered silver nanoparticles film. The simulation results indicate that the effective thermal conductivity of film is different at different directions and would be enhanced when the pore angle is 90. The simulation results will help us to further understand the heat transfer process across highly porous structures and will provide us a powerful guide to design coating with high thermal insulation or conductor property. Because of there is no similar experimental data for this simulation results, this paper is a comparative work among three different models.

  19. Polymer powders for selective laser sintering (SLS)

    Science.gov (United States)

    Schmid, Manfred; Amado, Antonio; Wegener, Konrad

    2015-05-01

    Selective Laser Sintering (SLS) is close to be accepted as a production technique (Additive Manufacturing). However, one problem limiting employment of SLS for additive manufacturing in a wide-ranging industrial scope is the narrow variety of applicable polymers. The commonly applied SLS powder to date is polyamide 12 (PA 12). PA 12 or ccompounds of PA 12 (dry blends) are approximately 90 % of complete industrial consumption. The remaining small quantity is distributed on polyamide 11 (PA11) and some other `exotic' polymers (TPU, PEBA, P(E)EK). Industry is awaiting commodity polymers like polypropylene (PP) or polyethylene (PE) crucial to open new market segments. But several approaches launching those polymers failed. But what are the reasons for the difficulties in developing new SLS powders? The contribution is to answer this and highlights the combination of intrinsic and extrinsic polymer properties necessary to generate a polymer powder promising for SLS application. Particle shape, powder distribution, thermal, rheological and optical requirements must be considered and only a particularly controlled property combination leads to successful SLS implementation. Thermal behavior, particle shape and -distribution is discussed in detail, although the other properties can't be disregarded for providing new commercially successful SLS powder finally.

  20. Microwave combustion and sintering without isostatic pressure

    International Nuclear Information System (INIS)

    Ebadian, M.A.

    1998-01-01

    In recent years interest has grown rapidly in the application of microwave energy to the processing of ceramics, composites, polymers, and other materials. Advances in the understanding of microwave/materials interactions will facilitate the production of new ceramic materials with superior mechanical properties. One application of particular interest is the use of microwave energy for the mobilization of uranium for subsequent redeposition. Phase III (FY98) will focus on the microwave assisted chemical vapor infiltration tests for mobilization and redeposition of radioactive species in the mixed sludge waste. Uranium hexachloride and uranium (IV) borohydride are volatile compounds for which the chemical vapor infiltration procedure might be developed for the separation of uranium. Microwave heating characterized by an inverse temperature profile within a preformed ceramic matrix will be utilized for CVI using a carrier gas. Matrix deposition is expected to commence from the inside of the sample where the highest temperature is present. The preform matrix materials, which include aluminosilicate based ceramics and silicon carbide based ceramics, are all amenable to extreme volume reduction, densification, and vitrification. Important parameters of microwave sintering such as frequency, power requirement, soaking temperature, and holding time will be investigated to optimize process conditions for the volatilization of uranyl species using a reactive carrier gas in a microwave chamber

  1. Damage Behavior of Sintered Fiber Felts

    Directory of Open Access Journals (Sweden)

    Nicolas Lippitz

    2015-04-01

    Full Text Available The reduction of aircraft noise is important due to a rising number of flights and the growth of urban centers close to airports. During landing, a significant part of the noise is generated by flow around the airframe. To reduce that noise porous trailing edges are investigated. Ideally, the porous materials should to be structural materials as well. Therefore, the mechanical properties and damage behavior are of major interest. The aim of this study is to show the change of structure and the damage behavior of sintered fiber felts, which are promising materials for porous trailing edges, under tensile loading using a combination of tensile tests and three dimensional computed tomography scans. By stopping the tensile test after a defined stress or strain and scanning the sample, it is possible to correlate structural changes and the development of damage to certain features in the stress-strain curve and follow the damage process with a high spatial resolution. Finally, the correlation between material structure and mechanical behavior is demonstrated.

  2. Optimum coagulant forecasting by modeling jar test experiments using ANNs

    Directory of Open Access Journals (Sweden)

    S. Haghiri

    2018-01-01

    Full Text Available Currently, the proper utilization of water treatment plants and optimizing their use is of particular importance. Coagulation and flocculation in water treatment are the common ways through which the use of coagulants leads to instability of particles and the formation of larger and heavier particles, resulting in improvement of sedimentation and filtration processes. Determination of the optimum dose of such a coagulant is of particular significance. A high dose, in addition to adding costs, can cause the sediment to remain in the filtrate, a dangerous condition according to the standards, while a sub-adequate dose of coagulants can result in the reducing the required quality and acceptable performance of the coagulation process. Although jar tests are used for testing coagulants, such experiments face many constraints with respect to evaluating the results produced by sudden changes in input water because of their significant costs, long time requirements, and complex relationships among the many factors (turbidity, temperature, pH, alkalinity, etc. that can influence the efficiency of coagulant and test results. Modeling can be used to overcome these limitations; in this research study, an artificial neural network (ANN multi-layer perceptron (MLP with one hidden layer has been used for modeling the jar test to determine the dosage level of used coagulant in water treatment processes. The data contained in this research have been obtained from the drinking water treatment plant located in Ardabil province in Iran. To evaluate the performance of the model, the mean squared error (MSE and correlation coefficient (R2 parameters have been used. The obtained values are within an acceptable range that demonstrates the high accuracy of the models with respect to the estimation of water-quality characteristics and the optimal dosages of coagulants; so using these models will allow operators to not only reduce costs and time taken to perform

  3. Condutivity effect in electro-coagulation-flotation applied to physico-chemical wastewater treatment

    Directory of Open Access Journals (Sweden)

    Francisco Javier Cuba Terán

    2007-03-01

    Full Text Available This study reports on the effect of conductivity on the simultaneous applicability of water electrolysis , chemical coagulation and flotation fundamentals in the treatment of wastewater with large amounts of suspended matter, characterizing electro-coagulation-flotation (ECF . Results from experiments carried out in a pilot study implanted and operated in the Laboratory of Environment Control (LCA, at the State University of Campinas in Limeira are presented. ECF was developed in an electrolytic reactor where water passed through aluminum electrodes connected to a power supply. Electrochemical reactions promoted Al3+ ions emission from anode, neutralizing repulsive pollutant forces, forming flakes. An evolution of micro hydrogen bubbles occurred, carrying the flakes to the top of the solution, causing flotation and polluter removal. System monitoring aimed at reaching optimal operation conditions regarding time of liquid permanence in the reactor, influence of the NaC1 addition on the increase of affluent conductivity, and influence of polarity inversion over cathodic passivation. Results from carwash wastewater treatment reported 86% efficiency rate for color, 90,15% for turbidity and 85,43% for oil and axle-grease removal.

  4. Intraoperative Changes in Blood Coagulation and Thrombelastographic Monitoring in Liver Transplantation

    Science.gov (United States)

    Kang, Yoo Goo; Martin, Douglas J.; Marquez, Jose; Lewis, Jessica H.; Bontempo, Franklin A.; Shaw, Byers W.; Starzl, Thomas E.; Winter, Peter M.

    2010-01-01

    The blood coagulation system of 66 consecutive patients undergoing consecutive liver transplantations was monitored by thrombelastograph and analytic coagulation profile. A poor preoperative coagulation state, decrease in levels of coagulation factors, progressive fibrinolysis, and whole blood clot lysis were observed during the preanhepatic and anhepatic stages of surgery. A further general decrease in coagulation factors and platelets, activation of fibrinolysis, and abrupt decrease in levels of factors V and VIII occurred before and with reperfusion of the homograft. Recovery of blood coagulability began 30–60 min after reperfusion of the graft liver, and coagulability had returned toward baseline values 2 hr after reperfusion. A positive correlation was shown between the variables of thrombelastography and those of the coagulation profile. Thrombelastography was shown to be a reliable and rapid monitoring system. Its use was associated with a 33% reduction of blood and fluid infusion volume, whereas blood coagulability was maintained without an increase in the number of blood product donors. PMID:3896028

  5. Dry Sintered Metal Coating of Halloysite Nanotubes

    Directory of Open Access Journals (Sweden)

    James C. Nicholson

    2016-09-01

    Full Text Available Halloysite nanotubes (HNTs are a naturally-occurring aluminosilicate whose dimensions measure microns in length and tens of nanometers in diameter. Bonding defects between the alumina and silica lead to net negative and positive charges on the exterior and interior lumen, respectively. HNTs have been shown to enhance the material properties of polymer matrices and enable the sustained release of loaded chemicals, drugs, and growth factors. Due to the net charges, these nanotubes can also be readily coated in layered-depositions using the HNT exterior lumen’s net negative charge as the basis for assembly. These coatings are primarily done through wet chemical processes, the majority of which are limited in their use of desired chemicals, due to the polarity of the halloysite. Furthermore, this restriction in the type of chemicals used often requires the use of more toxic chemicals in place of greener options, and typically necessitates the use of a significantly longer chemical process to achieve the desired coating. In this study, we show that HNTs can be coated with metal acetylacetonates—compounds primarily employed in the synthesis of nanoparticles, as metal catalysts, and as NMR shift reagents—through a dry sintering process. This method was capable of thermally decaying the metal acetylacetonate, resulting in a free positively-charged metal ion that readily bonded to the negatively-charged HNT exterior, resulting in metallic coatings forming on the HNT surface. Our coating method may enable greater deposition of coated material onto these nanotubes as required for a desired application. Furthermore, the use of chemical processes using toxic chemicals is not required, thus eliminating exposure to toxic chemicals and costs associated with the disposal of the resultant chemical waste.

  6. Effects of Dy and Nb on the magnetic properties and corrosion resistance of sintered NdFeB

    International Nuclear Information System (INIS)

    Yu, L.Q.; Wen, Y.H.; Yan, M.

    2004-01-01

    Dy and Nb were added into the sintered NdFeB magnets with the aim of improving their magnetic properties and corrosion resistance. It was found that intrinsic coercivity of magnets is promoted whilst remanence is reduced as a result of Dy addition. Simultaneous addition of Dy and Nb not only gives rise to greatly improved coercivity, but also suppresses the undesirable effect of Dy on the remanence. The optimum magnetic properties were achieved when 1.0% Dy and 1.5% Nb were incorporated. Moreover, corrosion resistance of NdFeB magnets improves with the increase in the content of Dy and Nb

  7. IMPROVEMENT OF COAGULATION PROCESS FOR THE PRUT RIVER WATER TREATMENT USING ALUMINUM SULPHATE

    Directory of Open Access Journals (Sweden)

    Larisa Postolachi

    2015-06-01

    Full Text Available The aim of presented research was to optimize the treatment process of the Prut River water. In order to realize the proposed goal, there were studied the following factors which can improve the process of coagulation: (i the influence of stirring speed during coagulation and (ii the influence of the concentration of the coagulant solution added in the process of coagulation. The optimal conditions of coagulation were established using the Jar-test method. Application of the recommended procedure contribute to the reduction of the coagulant dose, the contact time, the aluminum concentration in water and the expenses for water treatment.

  8. Wastewater Treatment of Stone Cutting Industries by Coagulation Process

    Directory of Open Access Journals (Sweden)

    Mohammad Fahiminia

    2013-09-01

    Full Text Available Background & Aims of the Study: The wastewater created as a result of stone cutting industries enters some pools for re-consumption so that its suspended solids settle by gravity. By taking to account the high volume of water and sludge, treatment of wastewater and removal of sludge cause many problems for stone cutting units. The objective of this study was to determine the quality of wastewater and to investigate the effects of coagulants on suspended solids removal efficiency from wastewater of some stone cutting industries (Qom, Iran. Materials & Methods: In this experimental study, the effects of different doses of coagulants including Alum, poly aluminum chloride, Polymer, Ferric chloride (Fecl3 and Lime on Turbidity, “total suspended solids” (TSS and “total solids” (TS removal were investigated by Jar Test. Removal efficiency of different coagulates was estimated. Results: The results indicated that lime in dose 100 PPM is the best coagulant for turbidity removal and the highest efficiency for TS removal is related to using Alum in dose 100 PPM. Conclusions: Considering the findings of this study, it can be concluded that using coagulants causes reduction in settling time and speeds up the return of water to the consumption cycle of stone cutting factories, and also increases turbidity removal efficiency.

  9. Vegetable coagulants as alternative for treatment of wastewater in Mexico

    Directory of Open Access Journals (Sweden)

    Servando López-León

    2017-11-01

    Full Text Available This review addresses the various properties of natural coagulants, water, the chemical substance essential for life and the ideal solvent for a large number of compounds, it is commonly used with domestic, commercial and industrial purposes. After its use, it presents sewage to be retired before use it once again. To remove pollutant, water is subject to different physical, chemical and biological processes. Here, the clarification process uses aluminum and iron materials to remove the solids present; these materials are reported as health hazardous and toxic. In Mexico, regulatory frame work stablish that treated wastewater should do not exceed 0.2 mg/L of aluminum even though has been reported an increased risk of Alzheimer's in populations when water exceeds 0.1 mg/L. Natural coagulants have showed coagulation properties when are used in the clarification process, proven its advantages over traditional ones; such as low cost, good coagulant properties and safe health and non-toxic properties. Here, we enlist some vegetable species as alternatives to the traditional based on aluminum and iron. Additionally, these species are known to have origins on Mexico or being present extensively in the territory, making possible to think about them as alternative coagulants in the clarification process of the wastewater treatment process.

  10. Improvement of wastewater treatment by use of natural coagulants

    Directory of Open Access Journals (Sweden)

    Jelena Prodanović

    2013-06-01

    Full Text Available An activated sludge and other organic sludges from wastewater treatment processes are usually anaerobically digested prior to application on land. The purpose of digestion is to convert bulky, odorous sludges to relatively inert material that can be rapidly dewatering. The important benefit of this process is a biogas production, too. It is proper to enlarge primary sludge production in a primary settler by adding some coagulation aids, with aim to increase a biogas production, as much as possible. The most common coagulant is alum, but presence of large quantities of aluminum salts in sludge has a harmful impact on digestion and digested sludge application. Some natural coagulants, that have a numerous advantages, can be used instead of alum. Natural coagulants could be extracted from a different plant material, and considering the fact that they are of organic nature, the biogas yield can be enhanced by their presence. A plant material that remains after extraction can be used as a feed. The aim of this paper is a consideration of potential environmental benefits of substitution of alum by natural coagulant extracted from common bean seeds in sewage wastewater treatment process.

  11. Coagulation tests show significant differences in patients with breast cancer.

    Science.gov (United States)

    Tas, Faruk; Kilic, Leyla; Duranyildiz, Derya

    2014-06-01

    Activated coagulation and fibrinolytic system in cancer patients is associated with tumor stroma formation and metastasis in different cancer types. The aim of this study is to explore the correlation of blood coagulation assays for various clinicopathologic factors in breast cancer patients. A total of 123 female breast cancer patients were enrolled into the study. All the patients were treatment naïve. Pretreatment blood coagulation tests including PT, APTT, PTA, INR, D-dimer, fibrinogen levels, and platelet counts were evaluated. Median age of diagnosis was 51 years old (range 26-82). Twenty-two percent of the group consisted of metastatic breast cancer patients. The plasma level of all coagulation tests revealed statistically significant difference between patient and control group except for PT (p50 years) was associated with higher D-dimer levels (p=0.003). Metastatic patients exhibited significantly higher D-dimer values when compared with early breast cancer patients (p=0.049). Advanced tumor stage (T3 and T4) was associated with higher INR (p=0.05) and lower PTA (p=0.025). In conclusion, coagulation tests show significant differences in patients with breast cancer.

  12. Principles of dielectric blood coagulometry as a comprehensive coagulation test.

    Science.gov (United States)

    Hayashi, Yoshihito; Brun, Marc-Aurèle; Machida, Kenzo; Nagasawa, Masayuki

    2015-10-06

    Dielectric blood coagulometry (DBCM) is intended to support hemostasis management by providing comprehensive information on blood coagulation from automated, time-dependent measurements of whole blood dielectric spectra. We discuss the relationship between the series of blood coagulation reactions, especially the aggregation and deformation of erythrocytes, and the dielectric response with the help of clot structure electron microscope observations. Dielectric response to the spontaneous coagulation after recalcification presented three distinct phases that correspond to (P1) rouleau formation before the onset of clotting, (P2) erythrocyte aggregation and reconstitution of aggregates accompanying early fibrin formation, and (P3) erythrocyte shape transformation and/or structure changes within aggregates after the stable fibrin network is formed and platelet contraction occurs. Disappearance of the second phase was observed upon addition of tissue factor and ellagic acid for activation of extrinsic and intrinsic pathways, respectively, which is attributable to accelerated thrombin generation. A series of control experiments revealed that the amplitude and/or quickness of dielectric response reflect platelet function, fibrin polymerization, fibrinolysis activity, and heparin activity. Therefore, DBCM sensitively measures blood coagulation via erythrocytes aggregation and shape changes and their impact on the dielectric permittivity, making possible the development of the battery of assays needed for comprehensive coagulation testing.

  13. Coagulation Management in Jersey Calves: An ex vivo Study.

    Science.gov (United States)

    Gröning, Sabine; Maas, Judith; van Geul, Svenja; Rossaint, Rolf; Steinseifer, Ulrich; Grottke, Oliver

    2017-01-01

    Jersey calves are frequently used as an experimental animal model for in vivo testing of cardiac assist devices or orthopedic implants. In this ex vivo study, we analyzed the coagulation system of the Jersey calves and the potential of human-based coagulation management to circumvent perioperative bleeding complications during surgery. Experimental Procedure: Blood from 7 Jersey calves was subjected to standard laboratory tests and thromboelastometry analysis. An ex vivo model of dilutional coagulopathy was used to study the effects of fibrinogen or prothrombin complex concentrate supplementation. Fibrinolysis was induced with tissue plasminogen activator to identify potential therapeutic strategies involving tranexamic acid or aprotinin. Furthermore, anticoagulation strategies were evaluated by incubating the blood samples with dabigatran or rivaroxaban. Baseline values for thromboelastometry and standard laboratory parameters, including prothrombin time, activated partial thromboplastin time, fibrinogen, antithrombin III, and D-dimers, were established. Fifty percent diluted blood showed a statistically significant impairment of hemostasis. The parameters significantly improved after the administration of fibrinogen or prothrombin complex concentrate. Tranexamic acid and aprotinin ameliorated tissue plasminogen activator-induced fibrinolysis. Both dabigatran and rivaroxaban significantly prolonged the coagulation parameters. In this ex vivo study, coagulation factors, factor concentrate, antifibrinolytic reagents, and anticoagulants regularly used in the clinic positively impacted coagulation parameters in Jersey calf blood. © 2017 S. Karger AG, Basel.

  14. Cell response to hydroxyapatite surface topography modulated by sintering temperature.

    Science.gov (United States)

    Mealy, Jacob; O'Kelly, Kevin

    2015-11-01

    Increased mesenchymal stem cell (MSC) activity on hydroxyapatite (HA) bone tissue engineering scaffolds will improve their viability in diffusion-based in vivo environments and is therefore highly desirable. This work focused on modulating the sintered HA surface topography with a view to increasing cell activity; this was achieved by varying the sintering temperature of the HA substrates. Cells were cultured on the substrates for periods of up to 19 days and displayed a huge variation in viability. MSC metabolic activity was measured using a resazurin sodium salt assay and revealed that surfaces sintered from 1250 to 1350°C significantly outperformed their lower temperature counterparts from day one (p ≤ 0.05). Surfaces sintered at 1300°C induced 57% more cell activity than the control at day 16. No significant activity was observed on surfaces sintered below 1200°C. It is suggested that this is due to the granular morphology produced at these temperatures providing insufficient contact area for cell attachment. In addition, we propose the average surface wavelength as a more quantitative surface descriptor than those readily found in the literature. The wavelengths of the substrates presented here were highly correlated with cell activity (R(2)  = 0.9019); with a wavelength of 2.675 µm on the 1300°C surface inducing the highest cell response. © 2015 Wiley Periodicals, Inc.

  15. Consolidation of metallic hollow spheres by electric sintering

    Science.gov (United States)

    Mironov, V.; Tatarinov, A.; Lapkovsky, V.

    2017-07-01

    This paper considers peculiarities of the technology of production of structures from metallic hollow spheres (MHS) using magnetic fields and electric sintering. In these studies, the raw material was MHS obtained by burning of polystyrene balls coated by carbon steel. MHS had an outer diameter of 3-5 mm and a steel wall thickness of 70-120 microns. Pulsed current generators were used for electric sintering of MHS to obtain different spatial structures. Since MHS have small strength, the compressive pressure during sintering should be minimal. To improve the adhesion strength and reduce the required energy for sintering, hollow spheres were coated with copper by ion-plasma sputtering in vacuum. The coating thickness was 10-15 microns. The ferromagnetic properties of MHS allowed using of magnet fields for orientation of the spheres in the structures, as well as using of perforated tapes acting as orienting magnetic cores. Ultrasonic testing of MHS structures has been tried using through propagation of ultrasound in low kilohertz frequency range. Sensitivity of the propagation parameters to water filling of inter-spheres space and sintering temperature was demonstrated.

  16. Leaching of metals from fresh and sintered red mud.

    Science.gov (United States)

    Ghosh, Indrani; Guha, Saumyen; Balasubramaniam, R; Kumar, A V Ramesh

    2011-01-30

    The disposal of red mud, a solid waste generated during the extraction of alumina from bauxite, is one of the major problems faced by the aluminum industry. Proper disposal followed by its utilization, for example as bricks, can provide a satisfactory solution to this problem. Pollution potential of red mud and its finished product, due to metals leaching out from them under certain environmental conditions, need to be studied. Sintering of red mud was performed in a resistance type vertical tube furnace to simulate the brick-making conditions in lab-scale. Leachability of metals in red mud and the sintered product was evaluated by performing sequential extraction experiments on both. The metals studied were the 'macro metals' iron and aluminum and the 'trace metals' copper and chromium. The total extractabilities of all the metals estimated by the microwave digestion of red mud samples decreased due to sintering. The leachability in sequential extraction of the macro metals iron and aluminum, on the other hand, increased due to sintering in all phases of sequential extraction. However, the effect of sintering on the leachability of the trace metals by sequential extraction was different for copper and chromium in different fractions of sequential extraction. Copyright © 2010 Elsevier B.V. All rights reserved.

  17. Low sintering temperature glass waste forms for sequestering radioactive iodine

    Science.gov (United States)

    Nenoff, Tina M.; Krumhansl, James L.; Garino, Terry J.; Ockwig, Nathan W.

    2012-09-11

    Materials and methods of making low-sintering-temperature glass waste forms that sequester radioactive iodine in a strong and durable structure. First, the iodine is captured by an adsorbant, which forms an iodine-loaded material, e.g., AgI, AgI-zeolite, AgI-mordenite, Ag-silica aerogel, ZnI.sub.2, CuI, or Bi.sub.5O.sub.7I. Next, particles of the iodine-loaded material are mixed with powdered frits of low-sintering-temperature glasses (comprising various oxides of Si, B, Bi, Pb, and Zn), and then sintered at a relatively low temperature, ranging from 425.degree. C. to 550.degree. C. The sintering converts the mixed powders into a solid block of a glassy waste form, having low iodine leaching rates. The vitrified glassy waste form can contain as much as 60 wt % AgI. A preferred glass, having a sintering temperature of 500.degree. C. (below the silver iodide sublimation temperature of 500.degree. C.) was identified that contains oxides of boron, bismuth, and zinc, while containing essentially no lead or silicon.

  18. [Influence on microstructure of dental zirconia ceramics prepared by two-step sintering].

    Science.gov (United States)

    Jian, Chao; Li, Ning; Wu, Zhikai; Teng, Jing; Yan, Jiazhen

    2013-10-01

    To investigate the microstructure of dental zirconia ceramics prepared by two-step sintering. Nanostructured zirconia powder was dry compacted, cold isostatic pressed, and pre-sintered. The pre-sintered discs were cut processed into samples. Conventional sintering, single-step sintering, and two-step sintering were carried out, and density and grain size of the samples were measured. Afterward, T1 and/or T2 of two-step sintering ranges were measured. Effects on microstructure of different routes, which consisted of two-step sintering and conventional sintering were discussed. The influence of T1 and/or T2 on density and grain size were analyzed as well. The range of T1 was between 1450 degrees C and 1550 degrees C, and the range of T2 was between 1250 degrees C and 1350 degrees C. Compared with conventional sintering, finer microstructure of higher density and smaller grain could be obtained by two-step sintering. Grain growth was dependent on T1, whereas density was not much related with T1. However, density was dependent on T2, and grain size was minimally influenced. Two-step sintering could ensure a sintering body with high density and small grain, which is good for optimizing the microstructure of dental zirconia ceramics.

  19. Granulation of coke breeze fine for using in the sintering process

    Directory of Open Access Journals (Sweden)

    Mohamed F.M.

    2010-01-01

    Full Text Available Coke breeze is the main fuel used in the sintering process. The value of -3+1 mm. represents the most favorable particle size for coke breeze in the sintering process. About 20% of total coke fines (-0.5 mm are produced during different steps of preparation. Introducing these fines during the sintering process proves to be very harmful for different operating parameters. Thus ,this study aims at investigating the production of granules resulting from these fines using molasses as organic binder and its application in sintering of an iron ore. The results showed that the granules having the highest mechanical properties were obtained with 14.5 wt % molasses addition. The sintering experiments were performed by using coke breeze in different shapes (-3+1 mm in size, coke breeze without sieving and coke breeze granules -3+1 mm. The reduction experiments, microscopic structure and X-ray analysis for the produced sinter were carried out. The results revealed that, all sinter properties (such as shatter test, productivity of sinter machine and blast furnace, reduction time and chemical composition for produced sinter by using coke breeze with size -3+1 mm and coke breeze granules were almost the same. The iron ore sinter which was produced by using coke breeze without sieving yielded low productivity for both sinter machine and blast furnace. Furthermore, using coke breeze without sieving in sintering of an iron ore decreases the vertical velocity of sinter machine and increases the reduction time.

  20. Removal Natural Organic Matter (NOM in Peat Water from Wetland Area by Coagulation-Ultrafiltration Hybrid Process with Pretreatment Two-Stage Coagulation

    Directory of Open Access Journals (Sweden)

    Mahmud Mahmud

    2013-11-01

    Full Text Available The primary problem encountered in the application of membrane technology was membrane fouling. During this time, hybrid process by coagulation-ultrafiltration in drinking water treatment that has been conducted by some research, using by one-stage coagulation. The goal of this research was to investigate the effect of two-stage coagulation as a pretreatment towards performance of the coagulation-ultrafiltration hybrid process for removal NOM in the peat water. Coagulation process, either with the one-stage or two-stage coagulation was very good in removing charge hydrophilic fraction, i.e. more than 98%. NOM fractions of the peat water, from the most easily removed by the two-stage coagulation and one-stage coagulation process was charged hydrophilic>strongly hydrophobic>weakly hydrophobic>neutral hydrophilic. The two-stage coagulation process could removed UV254 and colors with a little better than the one-stage coagulation at the optimum coagulant dose. Neutral hydrophilic fraction of peat water NOM was the most influential fraction of UF membrane fouling. The two-stage coagulation process better in removing the neutral hidrophilic fraction, while removing of the charged hydrophilic, strongly hydrophobic and weakly hydrophobic similar to the one-stage coagulation. Hybrid process by pretreatment with two-stage coagulation, beside can increased removal efficiency of UV254 and color, also can reduced fouling rate of the ultrafiltration membraneIt must not exceed 250 words, contains a brief summary of the text, covering the whole manuscript without being too elaborate on every section. Avoid any abbreviation, unless it is a common knowledge or has been previously stated.

  1. Coercivity enhancements of Nd–Fe–B sintered magnets by diffusing DyHx along different axes

    International Nuclear Information System (INIS)

    Ma, Tianyu; Wang, Xuejiao; Liu, Xiaolian; Wu, Chen; Yan, Mi

    2015-01-01

    Diffusing heavy rare earth elements along the grain boundaries (GBs) for Nd 2 Fe 14 B-type sintered magnets serves as an effective method to enhance coercivity and to minimize remanence loss simultaneously. Considering the texture anisotropy of Nd-rich GB phases, the coercivity incremental difference by diffusing DyH x fine powders along or perpendicular to the  <0 0 1 >  easy axis (c-axis) has been investigated. The coercivity increases more rapidly to 20.61 kOe (5.76 kOe higher than that of the as-sintered state) when diffusing along the c-axis than that diffusing perpendicular to c-axis (18.85 kOe, 4.00 kOe higher than the as-sintered state). Microstructural investigation reveals that Dy diffuses more easily towards the magnet inner part when treating along the c-axis than that for the perpendicular case due to the anisotropic distribution of the Nd-rich phase. This is verified by a higher Dy content at equivalent diffusing depth and a much deeper final diffusion distance. The local Dy-containing fractions with a stronger anisotropy field are richer for the magnet treated along the c-axis, leading to the much rapider coercivity enhancement. This work reveals that diffusion heavy rare earth along the c-axis is more effective to enhance coercivity for aligned Nd–Fe–B sintered magnets. (paper)

  2. Combined coagulation flocculation pre treatment unit for municipal wastewater

    Directory of Open Access Journals (Sweden)

    Ibrahim M. Ismail

    2012-10-01

    Full Text Available The potentials of using the hydraulic technique in combined unit for municipal wastewater treatment were studied. A combined unit in which processes of coagulation, flocculation and sedimentation, has been designed utilizing hydraulic mixing instead of mechanical mixing. A jar test treatability study has been conducted to locate the optimum dose of the coagulants to be used. Alum, ferrous sulfate, ferric sulfate, a mixture of ferric and ferrous sulfates, and mixture of lime and ferrous sulfate were all tested. A pilot unit was constructed in the existing wastewater treatment plant at El Mansoura governorate located in north Egypt. The optimum dose of coagulants used in the combined unit gives removal efficiencies for COD, BOD, and total phosphorous as 65%, 55%, and 83%, respectively.

  3. Exploration by radioactive fibrinogen of intrarenal coagulation phenomena. Preliminary results

    International Nuclear Information System (INIS)

    Simon, Jacques.

    1974-01-01

    The participation of fibrin deposits in kidney pathology was studied by the use of a radioactive tracer involved in the coagulation phenomenon: iodine 131-labelled fibrinogen. The isotopic exploration consists of a fibrinogen kinetics study combined with external counting over the kidney regions. The different stages of the procedure are described: separation, purification and labelling of fibrinogen; characteristics of the radioactive fibrinogen used; practical details of the examination itself; data analysis method. A chapter devoted to verifications and discussions of the procedure is followed by a report on the exploration of intrarenal coagulation phenomena in 30 kidney disease patients. In conclusion, the study of fibrinogen kinetics is considered as the most suitable method to detect local or slight intravascular coagulation phenomena. The sensitivity of the isotopic exploration is very satisfactory. The main criticism directed against this method is that the exploration is general and therefore blind [fr

  4. Exact results for the Boltzmann equation and Smoluchowski's coagulation equation

    International Nuclear Information System (INIS)

    Hendriks, E.M.

    1983-01-01

    Almost no analytical solutions have been found for realistic intermolecular forces, largely due to the complicated structure of the collision term which calls for the construction of simplified models, in which as many physical properties are maintained as possible. In the first three chapters of this thesis such model Boltzmann equations are studied. Only spatially homogeneous gases with isotropic distribution functions are considered. Chapter I considers transition kernels, chapter II persistent scattering models and chapter III very hard particles. The second part of this dissertation deals with Smoluchowski's coagulation equation for the size distribution function in a coagulating system, with chapters devoted to the following topics: kinetics of gelation and universality, coagulation equations with gelation and exactly soluble models of nucleation. (Auth./C.F.)

  5. Removal of humic substances for coagulation with Alum

    International Nuclear Information System (INIS)

    Camargo Valero, Miller; Cruz Torres, Luis Eduardo

    1999-01-01

    In the search of better conditions to remove precursory material in the formation of disinfections sub-products with free chlorine, was found that the absorbance to the ultraviolet to 254 nm (AUV 254 nm) it is a parameter that can be used as non-specific measure, to estimate concentrations of precursory material, specifically humic substances, and also, like control instrument in the operations and previous processes to the disinfections with free chlorine. The study tries the importance so that in the handling essays of potable water is included the AUV 254 nm like control parameter. In essays of coagulation with alum was found that the removal of these substances depends on the dose of coagulation and the pH of coagulation

  6. Valproic acid modulates platelet and coagulation function ex vivo

    DEFF Research Database (Denmark)

    Bambakidis, Ted; Dekker, Simone E; Halaweish, Ihab

    2017-01-01

    of coagulopathy, it remains unknown whether this is a direct effect of the drug, or the establishment of an overall prosurvival phenotype. We thus conducted an ex-vivo experiment to determine if VPA has an effect on coagulation and platelet function. Ten swine were subjected to traumatic brain injury (TBI......) and hemorrhagic shock (HS). Blood samples were drawn prior to TBI+HS insult (Healthy group) and 2 h following TBI+HS (Shock group). Samples were incubated with VPA or vehicle controls for 1 h. Platelet aggregation was analyzed via impedance aggregometry and coagulation was measured using thromboelastography....... Addition of VPA to the healthy blood did not affect platelet aggregation or coagulation parameters. In shock blood, incubation with VPA significantly reduced collagen-(P = 0.050), arachidonic acid-(P = 0.005), and adenosine diphosphate-(P = 0.023) induced platelet aggregation. VPA also significantly...

  7. Mathematical Modeling of Intravascular Blood Coagulation under Wall Shear Stress

    Science.gov (United States)

    Rukhlenko, Oleksii S.; Dudchenko, Olga A.; Zlobina, Ksenia E.; Guria, Georgy Th.

    2015-01-01

    Increased shear stress such as observed at local stenosis may cause drastic changes in the permeability of the vessel wall to procoagulants and thus initiate intravascular blood coagulation. In this paper we suggest a mathematical model to investigate how shear stress-induced permeability influences the thrombogenic potential of atherosclerotic plaques. Numerical analysis of the model reveals the existence of two hydrodynamic thresholds for activation of blood coagulation in the system and unveils typical scenarios of thrombus formation. The dependence of blood coagulation development on the intensity of blood flow, as well as on geometrical parameters of atherosclerotic plaque is described. Relevant parametric diagrams are drawn. The results suggest a previously unrecognized role of relatively small plaques (resulting in less than 50% of the lumen area reduction) in atherothrombosis and have important implications for the existing stenting guidelines. PMID:26222505

  8. Mutations targeting the coagulation pathway are enriched in brain metastases.

    Science.gov (United States)

    Richichi, Cristina; Fornasari, Lorenzo; Melloni, Giorgio E M; Brescia, Paola; Patanè, Monica; Del Bene, Massimiliano; Mustafa, Dana A M; Kros, Johan M; Pollo, Bianca; Pruneri, Giancarlo; Sciandivasci, Angela; Munzone, Elisabetta; DiMeco, Francesco; Pelicci, Pier Giuseppe; Riva, Laura; Pelicci, Giuliana

    2017-07-26

    Brain metastases (BMs) are the most common malignancy of the central nervous system. Recently it has been demonstrated that plasminogen activator inhibitor serpins promote brain metastatic colonization, suggesting that mutations in serpins or other members of the coagulation cascade can provide critical advantages during BM formation. We performed whole-exome sequencing on matched samples of breast cancer and BMs and found mutations in the coagulation pathway genes in 5 out of 10 BM samples. We then investigated the mutational status of 33 genes belonging to the coagulation cascade in a panel of 29 BMs and we identified 56 Single Nucleotide Variants (SNVs). The frequency of gene mutations of the pathway was significantly higher in BMs than in primary tumours, and SERPINI1 was the most frequently mutated gene in BMs. These findings provide direction in the development of new strategies for the treatment of BMs.

  9. TRAITEMENT DES EAUX USEES PAR COAGULATION-FLOCULATION EN UTILISANT LE SULFATE D’ALUMINIUM COMME COAGULANT

    Directory of Open Access Journals (Sweden)

    Nora SEGHAIRI

    2017-12-01

    Full Text Available Domestic wastewater treatment by coagulation-flocculation is widely used internationally. This treatment reduces color and turbidity, indicating organic and inorganic contaminants, but at acceptable levels for treated waste water discharged into the receiving environment. The objective of this study is to optimize the treatment of wastewater by coagulation-flocculation using aluminum sulphate as a coagulant. Various reaction parameters are taken into account, such as the coagulant dose, the pH of the solutions, the conductivity, the BOD5, the nitrates, the ammonium and the phosphates. We found from the different results obtained the optimal dose of aluminum sulphate is 400 mg/l with a reduction of 96.31%, 82.44% 90.95% and 78.74% respectively for phosphates, nitrates, ammonium and BOD5. It is recognized that pH influences the abatement rates of pollution contained in wastewater. For each water, there is a pH range for which coagulation- flocculation takes place rapidly. For our study, the optimum pH for removal of BOD5 and ammonium is between 6 and 7.

  10. Biological and analytical variations of 16 parameters related to coagulation screening tests and the activity of coagulation factors.

    Science.gov (United States)

    Chen, Qian; Shou, Weiling; Wu, Wei; Guo, Ye; Zhang, Yujuan; Huang, Chunmei; Cui, Wei

    2015-04-01

    To accurately estimate longitudinal changes in individuals, it is important to take into consideration the biological variability of the measurement. The few studies available on the biological variations of coagulation parameters are mostly outdated. We confirmed the published results using modern, fully automated methods. Furthermore, we added data for additional coagulation parameters. At 8:00 am, 12:00 pm, and 4:00 pm on days 1, 3, and 5, venous blood was collected from 31 healthy volunteers. A total of 16 parameters related to coagulation screening tests as well as the activity of coagulation factors were analyzed; these included prothrombin time, fibrinogen (Fbg), activated partial thromboplastin time, thrombin time, international normalized ratio, prothrombin time activity, activated partial thromboplastin time ratio, fibrin(-ogen) degradation products, as well as the activity of factor II, factor V, factor VII, factor VIII, factor IX, and factor X. All intraindividual coefficients of variation (CVI) values for the parameters of the screening tests (except Fbg) were less than 5%. Conversely, the CVI values for the activity of coagulation factors were all greater than 5%. In addition, we calculated the reference change value to determine whether a significant difference exists between two test results from the same individual. Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

  11. Coagulation management in trauma-associated coagulopathy: allogenic blood products versus coagulation factor concentrates in trauma care.

    Science.gov (United States)

    Klages, Matthias; Zacharowski, Kai; Weber, Christian Friedrich

    2016-04-01

    Coagulation management by transfusion of allogenic blood products and coagulation factors are competing concepts in current trauma care. Rapid and adequate therapy of trauma-associated coagulopathy is crucial to survival of severely injured patients. Standard coagulation tests such as prothrombin time and activated partial thromboplastin time are commonly used, but these tests are inappropriate for monitoring and guiding therapy in trauma patients. Coagulation factor-based treatment showed promising results, but randomized trials have not yet been performed. In addition, viscoelastic tests are needed to guide therapy, although there is in fact limited evidence for these in tests in trauma care. Regarding transfusion therapy with allogenic blood products, plasma transfusion has been associated with improved survival in trauma patients following massive transfusion. In contrast, patients not requiring massive transfusion seem to be at risk for suffering complications with increasing volumes of plasma transfused. The collective of trauma patients is heterogeneous. Despite the lack of evidence, there are strong arguments for individualized patient treatment with coagulation factors for some indications and to abstain from the use of fresh frozen plasma. In patients with severe trauma and major bleeding, plasma, platelets, and red blood cells should be considered to be administered at a ratio of 1 : 1 : 1.

  12. High performance sinter-HIP for hard metals

    International Nuclear Information System (INIS)

    Hongxia Chen; Deming Zhang; Yang Li; Jingping Chen

    2001-01-01

    The horizontal sinter-HIP equipment with great charge capacity and high performance, developed and manufactured by Central Iron and Steel Research Institute(CISRI), is mainly used for sintering and condensation of hard metals. This equipment is characterized by large hot zone, high heating speed, good temperature uniformity and fast cooling system. The equipment can provide uniform hot zone with temperature difference less than 6 o C at 1500-1600 o C and 6-10 MPa by controlling temperature, pressure and circulation of gas precisely. Using large scale horizontal sinter-HIP equipment to produce hard matals have many advantages such as stable quality, high efficiency of production, high rate of finished products and low production cost, so this equipment is a good choice for manufacturer of hard metals. (author)

  13. Electric Field-Assisted Pressureless Sintering of Ceramic Protonic Conductors

    DEFF Research Database (Denmark)

    Muccillo, R.; Esposito, Vincenzo; Zanetti De Florio, Daniel

    2017-01-01

    -5 A the electric current pulse amplitude. The sintering experiments were carried out in ambient atmosphere with the pellets positioned inside a vertical dilatometer furnace with Pt-Ir electrodes connected either to a power supply for applying the electric field or to an impedance analyzer for collecting [-Z''(ω) x......Gadolinium, yttrium and samarium-doped barium cerate (BCGd, BCY and BCSm, respectively) polycrystalline green pellets were submitted to electric field-assisted pressureless sintering experiments isothermally in the temperature range 800-1200oC under 100-200 V cm-1 electric fields, limiting to 1...... of the electrical conductivity of flash sintered specimens. Joule heating is assumed to be the primary effect of the electric current pulse through the specimens. Improved grain-to-grain contact and the removal of depleted chemical species due to Joule heating at the space charge region are proposed, respectively...

  14. Modeling Macroscopic Shape Distortions during Sintering of Multi-layers

    DEFF Research Database (Denmark)

    Tadesse Molla, Tesfaye

    Ceramic multi-layered composites are being used as components in various technologies ranging from electronics to energy conversion devices. Thus, different architectures of multi-layers involving ceramic materials are often required to be produced by powder processing, followed by sintering...... the camber development during co-firing. The effect of extrinsic factors (e.g. gravity, thickness ratio and friction) on the shape evolution of bi-layers during co-firing has been studied using the developed model and experiments. Furthermore, a new analytical model describing stresses during sintering...... of tubular bi-layer structures has been developed by using the direct correspondence between elasticity and linear viscous problems. The finite element model developed in this study and sintering experiments of tubular bi-layer sample have been used to verify and validate the developed analytical model...

  15. CdS sintered films: growth and characteristics

    International Nuclear Information System (INIS)

    Sharma, Monika; Kumar, Sushil; Sharma, L.M.; Sharma, T.P.; Husain, M.

    2004-01-01

    Cadmium sulphide finds extensive applications in a variety of optoelectronic devices. CdS, with a band gap of 2.43 eV, is a suitable window material in heterojunction solar cells that employ CdTe, Cu 2 S or CuInSe 2 as an absorber. Polycrystalline films of CdS, thickness ∼15 μm, were grown onto chemically clean and optically plane glass substrates by sintering process. A 10 min sintering time and 500 deg. C sintering temperature were found to be optimum. As deposited films were characterized through optical, structural and electrical transport properties using optical reflection spectroscopy, X-ray diffractometry and I-V characteristics techniques

  16. Nano pores evolution in hydroxyapatite microsphere during spark plasma sintering

    Directory of Open Access Journals (Sweden)

    Lin C.

    2011-01-01

    Full Text Available Micron-spherical granules of hydroxyapatite (HAp nanoparticles were prepared by powder granulation methods. Through subsequent sintering, porous HAp microspheres with tailored pore and grain framework structures were obtained. Detailed microstructure investigation by SEM and TEM revealed the correlation of the pore structure and the necking strength with the sintering profiles that determine the coalescence features of the nanoparticles. The partially sintered porous HAp microspheres containing more than 50% porosity consisting of pores and grains both in nano-scale are active in inducing the precipitation of HAp in simulated body fluid. The nano-porous HAp microspheres with an extensive surface and interconnecting pores thus demonstrate the potential of stimulating the formation of collagen and bone and the integration with the newly formed bones during physiological bone remodeling.

  17. Immobilization of high-level wastes into sintered glass: 1

    International Nuclear Information System (INIS)

    Russo, D.O.; Messi de Bernasconi, N.; Audero, M.A.

    1987-01-01

    In order to immobilize the high-level radioactive wastes from fuel elements reprocessing, borosilicate glass was adopted. Sintering experiments are described with the variety VG 98/12 (SiO 2 , TiO 2 , Al 2 O 3 , B 2 O 3 , MgO, CaO and Na 2 O) (which does not present devitrification problems) mixed with simulated calcinated wastes. The hot pressing line (sintering under pressure) was explored in two variants 1: In can; 2: In graphite matrix with sintered pellet extraction. With scanning electron microscopy it is observed that the simulated wastes do not disolve in the vitreous matrix, but they remain dispersed in the same. The results obtained point out that the leaching velocities are independent from the density and from the matrix type employed, as well as from the fact that the wastes do no dissolve in the matrix. (M.E.L.) [es

  18. High efficiency particulate removal with sintered metal filters

    International Nuclear Information System (INIS)

    Kirstein, B.E.; Paplawsky, W.J.; Pence, D.T.; Hedahl, T.G.

    1981-01-01

    Because of their particle removal efficiencies and durability, sintered metal filters have been chosen for HEPA filter protection in the off-gas treatment system for the proposed Idaho National Engineering Laboratory Transuranic Waste Treatment Facility. Process evaluation of sintered metal filters indicated a lack of sufficient process design data to assume trouble-free operation. Subsequent pilot-scale testing was performed with fly ash as the test particulate. The test results showed that the sintered metal filters can have an efficiency greater than 0.9999999 for the specific test conditions used. Stable pressure drop characteristics were observed in pulsed and reversed flow blowback modes of operation. Over 4900 hours of operation were obtained with operating conditions ranging up to approximately 90 0 C and 24 volume percent water vapor in the gas stream

  19. Evaluation of dilatometric techniques for studies of sintering kinetics

    International Nuclear Information System (INIS)

    El-Sayed Ali, M.; Toft Soerensen, O.

    1985-04-01

    The kinetics of the initial sintering stage of CeO 2 is evaluated by three different techniques: constant heating rate dilatometry, constant shrinkage rate dilatometry and a new technique recently introduced by the authors called Stepwise Isothermal Dilatometry (SID). Comparative measurements with these techniques showed that too high activation energies were obtained with the two first techniques, both of which can be termed as nonisothermal, whereas activation energies comparable to those reported for cation diffusion in other fluorite oxides were obtained with the latter technique. Of the three techniques SID is thus considered to be the most accurate for studies of the sintering kinetics. In contrast to the two nonisothermal techniques SID has the further advantage that both the controlling mechanism and its activation energy can be determined in a single experiment. From the SID-measurement it was concluded that the initial sintering stage of CeO 2 is controlled by grain-boundary diffusion. (author)

  20. High efficiency particulate removal with sintered metal filters

    International Nuclear Information System (INIS)

    Kirstein, B.E.; Paplawsky, W.J.; Pence, D.T.; Hedahl, T.G.

    1981-01-01

    Because of their particle removal efficiencies and durability, sintered metal filters have been chosen for high efficiency particulate air (HEPA) filter protection in the off-gas treatment system for the proposed Idaho National Engineering Laboratory Transuranic Waste Treatment Facility. Process evaluation of sintered metal filters indicated a lack of sufficient process design data to ensure trouble-free operation. Subsequence pilot scale testing was performed with flyash as the test particulate. The test results showed that the sintered metal filters can have an efficiency greater than 0.9999999 for the specific test conditions used. Stable pressure drop characteristics were observed in pulsed and reversed flow blowback modes of operation. Over 4900 hours of operation were obtained with operating conditions ranging up to approximately 90 0 C and 24 vol % water vapor in the gas stream

  1. Reactive Sintering of Bimodal WC-Co Hardmetals

    Directory of Open Access Journals (Sweden)

    Marek Tarraste

    2015-09-01

    Full Text Available Bimodal WC-Co hardmetals were produced using novel technology - reactive sintering. Milled and activated tungsten and graphite powders were mixed with commercial coarse grained WC-Co powder and then sintered. The microstructure of produced materials was free of defects and consisted of evenly distributed coarse and fine tungsten carbide grains in cobalt binder. The microstructure, hardness and fracture toughness of reactive sintered bimodal WC-Co hardmetals is exhibited. Developed bimodal hardmetal has perspective for demanding wear applications for its increased combined hardness and toughness. Compared to coarse material there is only slight decrease in fracture toughness (K1c is 14.7 for coarse grained and 14.4 for bimodal, hardness is increased from 1290 to 1350 HV units.DOI: http://dx.doi.org/10.5755/j01.ms.21.3.7511

  2. Characterizations of Rapid Sintered Nanosilver Joint for Attaching Power Chips

    Directory of Open Access Journals (Sweden)

    Shuang-Tao Feng

    2016-07-01

    Full Text Available Sintering of nanosilver paste has been extensively studied as a lead-free die-attach solution for bonding semiconductor power chips, such as the power insulated gated bipolar transistor (IGBT. However, for the traditional method of bonding IGBT chips, an external pressure of a few MPa is reported necessary for the sintering time of ~1 h. In order to shorten the processing duration time, we developed a rapid way to sinter nanosilver paste for bonding IGBT chips in less than 5 min using pulsed current. In this way, we firstly dried as-printed paste at about 100 °C to get rid of many volatile solvents because they may result in defects or voids during the out-gassing from the paste. Then, the pre-dried paste was further heated by pulse current ranging from 1.2 kA to 2.4 kA for several seconds. The whole procedure was less than 3 min and did not require any gas protection. We could obtain robust sintered joint with shear strength of 30–35 MPa for bonding 1200-V, 25-A IGBT and superior thermal properties. Static and dynamic electrical performance of the as-bonded IGBT assemblies was also characterized to verify the feasibility of this rapid sintering method. The results indicate that the electrical performance is comparable or even partially better than that of commercial IGBT modules. The microstructure evolution of the rapid sintered joints was also studied by scanning electron microscopy (SEM. This work may benefit the wide usage of nanosilver paste for rapid bonding IGBT chips in the future.

  3. Coagulation Testing in the Core Laboratory.

    Science.gov (United States)

    Winter, William E; Flax, Sherri D; Harris, Neil S

    2017-11-08

    Primary hemostasis begins with endothelial injury. VWF, produced by endothelial cells, binds to platelets and links them to subendothelial collagen. Platelet-derived ADP and thromboxane activate non-adhered platelets via their GPIIb/IIIa receptors, allowing these platelets to participate in platelet aggregation. Secondary hemostasis is initiated with the binding of factor VII to extravascular tissue factor (TF). Factors II, VII, IX and X are vitamin K-dependent factors. The role of vitamin K is to assist in the addition of gamma carboxylate groups to glutamic acids in the "GLA" domains of these factors.In vitro the intrinsic pathway is initiated when fresh whole blood is placed in a glass tube. The negative charge of the glass initiates the "contact pathway" where FXII is activated and then FXIa cleaves FIX to FIXa. The extrinsic pathway is triggered when tissue factor, phospholipid and calcium are added to plasma anticoagulated with citrate. In vitro, FVII is activated to FVIIa, and TF-FVIIa preferentially converts FX to FXa activating the common pathway.The prothrombin time is commonly used to monitor warfarin anticoagulant therapy. To correct for differences in reagent and instrument, the international normalized ratio was developed to improve standardization of PT reporting globally. The activated partial thromboplastin time (aPTT) is used to evaluate the intrinsic and common pathways of coagulation. The aPTT is useful clinically as a screening test for inherited and acquired factor deficiencies as well as to monitor unfractionated heparin therapy although the anti-Xa assay is now the preferred measure of the effects of unfractionated heparin. The Clauss assay is the most commonly performed fibrinogen assay and uses diluted plasma where clotting is initiated with a high concentration of reagent thrombin.The mixing study assists in the assessment of an abnormally prolonged PT or aPTT. An equal volume of citrated patient plasma is mixed with normal pooled plasma

  4. Predicting sintering deformation of ceramic film constrained by rigid substrate using anisotropic constitutive law

    International Nuclear Information System (INIS)

    Li Fan; Pan Jingzhe; Guillon, Olivier; Cocks, Alan

    2010-01-01

    Sintering of ceramic films on a solid substrate is an important technology for fabricating a range of products, including solid oxide fuel cells, micro-electronic PZT films and protective coatings. There is clear evidence that the constrained sintering process is anisotropic in nature. This paper presents a study of the constrained sintering deformation using an anisotropic constitutive law. The state of the material is described using the sintering strains rather than the relative density. In the limiting case of free sintering, the constitutive law reduces to a conventional isotropic constitutive law. The anisotropic constitutive law is used to calculate sintering deformation of a constrained film bonded to a rigid substrate and the compressive stress required in a sinter-forging experiment to achieve zero lateral shrinkage. The results are compared with experimental data in the literature. It is shown that the anisotropic constitutive law can capture the behaviour of the materials observed in the sintering experiments.

  5. Preparation of Ni-Ti shape memory alloy by spark plasma sintering method

    Czech Academy of Sciences Publication Activity Database

    Salvetr, P.; Kubatík, Tomáš František; Novák, P.

    2016-01-01

    Roč. 16, č. 4 (2016), s. 804-808 ISSN 1213-2489 Institutional support: RVO:61389021 Keywords : Ni-Ti alloy * Powder metallurgy * Reactive sintering * Spark plasma sintering Subject RIV: JK - Corrosion ; Surface Treatment of Materials

  6. Coagulation changes following traumatic brain injury and shock

    DEFF Research Database (Denmark)

    Sillesen, Martin

    2014-01-01

    with valproic acid (VPA). These most notably included coagulation and endothelial activation as well as platelet dysfunction. These results add to the growing body of evidence indicating a protective effect of VPA following trauma, and suggests that this may in part be mediated through an attenuation......In these studies, we have shown that coagulation and innate immunity pathways respond to trauma within minutes. Furthermore, the appearance of dysfunction of platelets as well as activation of the endothelium is rapidly manifested. Interestingly, many of these changes were attenuated by treatment...

  7. Extremely refractory Kawasaki disease with disseminated intravascular coagulation.

    Science.gov (United States)

    Koh, Young Kwon; Lee, Jae Hee; Park, Yeong Bong

    2017-07-01

    Disseminated intravascular coagulation is a rare complication of Kawasaki disease and appears in Kawasaki disease patients. We report a case of refractory Kawasaki disease complicated with disseminated intravascular coagulation and giant coronary aneurysm. A 5-month-old boy presented with Kawasaki disease with coagulopathy. Although the coagulopathy improved after fresh-frozen plasma and antithrombin-III administration, the fever persisted despite two rounds of intravenous immunoglobulin, along with intravenous methylprednisolone pulse therapy and infliximab administration. Despite all efforts to treatment, the patient had giant coronary aneurysms and died suddenly.

  8. Gastric explosion induced by argon plasma coagulation and prevention strategies.

    Science.gov (United States)

    Freiman, John Saul; Hampe, Toni

    2014-12-01

    We describe the occurrence of an iatrogenic explosion induced by argon plasma coagulation in a 70-year-old man undergoing gastroscopy. Combustible gases in the stomach may have been released by bacterial overgrowth as a result of partial gastric outlet obstruction (caused by a gastric tumor) and reduced acidity (from proton pump inhibitor therapy). We propose a stepwise process during upper endoscopy to prevent this devastating complication, comprising aspiration, preinsufflation with CO2, and then coagulation. Copyright © 2014 AGA Institute. Published by Elsevier Inc. All rights reserved.

  9. The mechanism and properties of acid-coagulated milk gels

    Directory of Open Access Journals (Sweden)

    Chanokphat Phadungath

    2005-03-01

    Full Text Available Acid-coagulated milk products such as fresh acid-coagulated cheese varieties and yogurt areimportant dairy food products. However, little is known regarding the mechanisms involved in gel formation, physical properties of acid gels, and the effects of processing variables such as heat treatment and gelation temperature on the important physical properties of acid milk gels. This paper reviews the modern concepts of possible mechanisms involved in the formation of particle milk gel aggregation, along with recent developments including the use of techniques such as dynamic low amplitude oscillatory rheology to observe the gel formation process, and confocal laser scanning microscopy to monitor gel microstructure.

  10. Pressure sintering and creep deformation: a joint modeling approach

    International Nuclear Information System (INIS)

    Notis, M.R.

    1979-10-01

    Work related to microchemical and microstructural aspects of the joint modeling of pressure sintering and creep in ceramic oxides is reported. Quantitative techniques for the microchemical analysis of ceramic oxides and for the examination of impurity segregation effects in polycrystalline ceramic materials were developed. This has included fundamental absorption corrections for the oxygen anion species as a function of foil thickness. The evolution in microstructure during the transition from intermediate stage to final stage densification during hot pressing of cobalt oxide and preliminary studies with doped oxides were studied. This work shows promise in using time-integrated microstructural effects to elucidate the role of impurities in the sintering of ceramic materials

  11. In situ Transmission Electron Microscopy of catalyst sintering

    DEFF Research Database (Denmark)

    DeLaRiva, Andrew T.; Hansen, Thomas Willum; Challa, Sivakumar R.

    2013-01-01

    Recent advancements in the field of electron microscopy, such as aberration correctors, have now been integrated into Environmental Transmission Electron Microscopes (TEMs), making it possible to study the behavior of supported metal catalysts under operating conditions at atomic resolution. Here......, we focus on in situ electron microscopy studies of catalysts that shed light on the mechanistic aspects of catalyst sintering. Catalyst sintering is an important mechanism for activity loss, especially for catalysts that operate at elevated temperatures. Literature from the past decade is reviewed...

  12. Pressure sintering and creep deformation: a joint modeling approach

    Energy Technology Data Exchange (ETDEWEB)

    Notis, M.R.

    1979-10-01

    Work related to microchemical and microstructural aspects of the joint modeling of pressure sintering and creep in ceramic oxides is reported. Quantitative techniques for the microchemical analysis of ceramic oxides and for the examination of impurity segregation effects in polycrystalline ceramic materials were developed. This has included fundamental absorption corrections for the oxygen anion species as a function of foil thickness. The evolution in microstructure during the transition from intermediate stage to final stage densification during hot pressing of cobalt oxide and preliminary studies with doped oxides were studied. This work shows promise in using time-integrated microstructural effects to elucidate the role of impurities in the sintering of ceramic materials.

  13. Method and apparatus for radio frequency ceramic sintering

    Science.gov (United States)

    Hoffman, Daniel J.; Kimrey, Jr., Harold D.

    1993-01-01

    Radio frequency energy is used to sinter ceramic materials. A coaxial waveguide resonator produces a TEM mode wave which generates a high field capacitive region in which a sample of the ceramic material is located. Frequency of the power source is kept in the range of radio frequency, and preferably between 60-80 MHz. An alternative embodiment provides a tunable radio frequency circuit which includes a series input capacitor and a parallel capacitor, with the sintered ceramic connected by an inductive lead. This arrangement permits matching of impedance over a wide range of dielectric constants, ceramic volumes, and loss tangents.

  14. Sintering of Kernel UO2 for High Temperature Reactor Fuel

    International Nuclear Information System (INIS)

    Sukarsono; Dwi-Heru-Sucahyo; Hidayati; Evi-Hertiviana; Bambang-Sugeng

    2000-01-01

    Sintering investigation of UO 2 gel has been done. The gel was preparedthrough two ways. The first, gel was produced using PVA as additive agent.The second gel was produced using HMTA and Urea as additive agent. From thepreparation of gel, the PVA method better than the urea - HMTA method,because was not necessary the cold temperature for sol preparation and alsowas not necessary the hot temperature for gelation process. After nextprocessing, the sintered gel of gel through PVA, also better than HMTAprocess. (author)

  15. Sintering and microstructure of ZnO varistor

    International Nuclear Information System (INIS)

    Leite, E.R.; Longo, E.; Varela, J.A.

    1987-01-01

    The sintering and microstructure of ZnO-Bi 2 O 3 (ZB) and ZuO-Sb 2 O 3 -CoO-Bi 2 O 3 (ZSCB) varistors in several temperatures, for one hour in dry air temperature were studied. The compounds were analyzed by scanning electron microscopy, X-ray diffraction, differential thermal analysis and the density and porosity were determined by mercury picnometry. The experimental results showed that the ZB and ZSCB system sinters by liquid means and that liquid will control the density and grain growth mechanisms. (E.G.) [pt

  16. Networks of enzymatically oxidized membrane lipids support calcium-dependent coagulation factor binding to maintain hemostasis

    NARCIS (Netherlands)

    Lauder, Sarah N; Allen-Redpath, Keith; Slatter, David A; Aldrovandi, Maceler; O'Connor, Anne; Farewell, Daniel; Percy, Charles L; Molhoek, Jessica E; Rannikko, Sirpa; Tyrrell, Victoria J; Ferla, Salvatore; Milne, Ginger L; Poole, Alastair W; Thomas, Christopher P; Obaji, Samya; Taylor, Philip R; Jones, Simon A.; de Groot, Phillip G; Urbanus, Rolf T; Hörkkö, Sohvi; Uderhardt, Stefan; Ackermann, Jochen; Vince Jenkins, P; Brancale, Andrea; Krönke, Gerhard; Collins, Peter W; O'Donnell, Valerie B

    2017-01-01

    Blood coagulation functions as part of the innate immune system by preventing bacterial invasion, and it is critical to stopping blood loss (hemostasis). Coagulation involves the external membrane surface of activated platelets and leukocytes. Using lipidomic, genetic, biochemical, and mathematical

  17. Low molecular weight heparin attenuates multiple organ failure in a murine model of disseminated intravascular coagulation

    NARCIS (Netherlands)

    Slofstra, Sjoukje H.; van 't Veer, Cornelis; Buurman, Wim A.; Reitsma, Pieter H.; ten Cate, Hugo; Spek, C. Arnold

    2005-01-01

    OBJECTIVE: Bacterial sepsis causes widespread vascular inflammation that frequently leads to disseminated intravascular coagulation (DIC). Although intravascular coagulation contributes to organ failure, it is often debated whether anticoagulant therapy produces any beneficial effects in patients

  18. Determination of optimum thermal debinding and sintering process parameters using Taguchi Method

    CSIR Research Space (South Africa)

    Seerane, M

    2015-07-01

    Full Text Available on the basis of obtaining a defect-free part after sintering and also determining a sintering time that gives high sintering density. Thermal debinding was conducted after solvent debinding. The feedstock used to produce green compacts composed of Ti6Al4V... International Light Metals Technology Conference (LMT 2015), Port Elizabeth, South Africa, July 27-29 Determination of Optimum Process for Thermal Debinding and Sintering using Taguchi Method SEERANE Mandya,*, CHIKWANDA Hildab, MACHAKA Ronaldc CSIR...

  19. Simultaneous Cake Cutting

    DEFF Research Database (Denmark)

    Balkanski, Eric; Branzei, Simina; Kurokawa, David

    2014-01-01

    We introduce the simultaneous model for cake cutting (the fair allocation of a divisible good), in which agents simultaneously send messages containing a sketch of their preferences over the cake. We show that this model enables the computation of divisions that satisfy proportionality — a popular...

  20. Comparison of Chemical Coagulation and Electrocoagulation for Boron Removal from Synthetic Wastewater Using Aluminium

    OpenAIRE

    Kartikaningsih Danis; Yao-Hui Huang

    2016-01-01

    Various techniques including conventional and advanced have been employed for the boron treatment from water and wastewater. The electrocoagulation involves an electrolytic reactor for coagulation/flotation with aluminium as anode and cathode. There is aluminium as coagulant to be used for removal which may induce secondary pollution in chemical coagulation. The purpose of this study is to investigate and compare the performance between electrocoagulation and chemical coagulation on boron rem...

  1. Enhancement of activated sludge dewatering performance by combined composite enzymatic lysis and chemical re-flocculation with inorganic coagulants: Kinetics of enzymatic reaction and re-flocculation morphology.

    Science.gov (United States)

    Chen, Zhan; Zhang, Weijun; Wang, Dongsheng; Ma, Teng; Bai, Runying

    2015-10-15

    The feasibility of combined process of composite enzymatic treatment and chemical flocculation with inorganic salt coagulants was investigated in this study. The evolution of extracellular polymeric substances (EPS) distribution, composition and morphological properties were analyzed to unravel the sludge conditioning mechanism. It was found that sludge filtration performance was deteriorated due to release of a large amount of biopolymers after enzymatic treatment. The change in EPS followed the pseudo-first-order kinetic equation well under enzymatic treatment. The feeding modes of enzymes had a significant influence on sludge lysis efficiency under compound enzymes treatment. Alpha amylase + protease was more effective in solubilization than other two addition modes (protease + α-amylase or simultaneous addition). The sludge floc re-formed and macromolecule biopolymers were effectively removed through coagulation process. At the same time, both of filtration rate and cake solid content of sludge treated with enzymes were improved with increasing dosage of coagulants, and ferric iron (FeCl3) had better performance in sludge dewaterability enhancement than polyaluminium chloride (PACl). In addition, sludge filtration property was slightly deteriorated, while the cake moisture reduction was favored at the optimal dosage of inorganic coagulants. Copyright © 2015 Elsevier Ltd. All rights reserved.

  2. Model for the evaluation and prediction of production rate of sinter ...

    African Journals Online (AJOL)

    A model has been derived for evaluation and prediction of production rate of sinter machine operating on vertical mode. The quadratic model expressed as: P = 0.4395 V – 0.0526 V2 + 0.54, showed that the production rate of the sinter machine was dependent on the vertical sintering height. The maximum deviation of the ...

  3. Influence of various manufacturing parameters on some characteristics of UO2 powders and their sintering behaviour

    International Nuclear Information System (INIS)

    Mintz, M.H.; Vaknin, Sh.; Kremener, A.; Hadari, Z.

    1977-02-01

    Various parameters in the process of manufacturing uranium dioxide are examined and their influence on the characteristics and sintering behaviour of the powders obtained established. In addition some correlations between the powder aggregates microstructure and their adhesion properties and sintering behaviour are indicated. Shrinkage during the sintering process is also discussed

  4. Application of fine-grained coke breeze fractions in the process of iron ore sintering

    Directory of Open Access Journals (Sweden)

    M. Niesler

    2014-01-01

    Full Text Available The testing cycle, described in the paper, included fine-grained coke breeze granulation tests and iron concentrate sintering tests with the use of selected granulate samples. The use of granulated coke breeze in the sintering process results in a higher process efficiency, shorter sintering duration and fuel saving.

  5. Sintering of uranium dioxide pellets (UO2) in an oxidizing atmosphere (C O2)

    International Nuclear Information System (INIS)

    Santos, G.R.T.

    1992-01-01

    This work consists in the study of the sintering process of U O 2 pellets in an oxidizing atmosphere. Sintering tests were performed in an CO 2 atmosphere and the influence of temperature and time on the pellets density and microstructure were verified. The results obtained were compared to those from the conventional sintering process and its efficiency was confirmed. (author)

  6. Fabrication of High Strength and Ductile Stainless Steel Fiber Felts by Sintering

    Science.gov (United States)

    Wang, J. Z.; Tang, H. P.; Qian, M.; Li, A. J.; Ma, J.; Xu, Z. G.; Li, C. L.; Liu, Y.; Wang, Y.

    2016-03-01

    Stainless steel fiber felts are important porous stainless steel products for a variety of industry applications. A systematic study of the sintering of 28- µm stainless steel fibers has been conducted for the first time, assisted with synchrotron radiation experiments to understand the evolution of the sintered joints. The critical sintering conditions for the formation of bamboo-like grain structures in the fiber ligaments were identified. The evolution of the number density of the sintered joints and the average sintered neck radius during sintering was assessed based on synchrotron radiation experiments. The optimum sintering condition for the fabrication of high strength and ductile 28- µm-diameter stainless steel fiber felts was determined to be sintering at 1000°C for 900 s. Sintering under this optimum condition increased the tensile strength of the as-sintered stainless steel fiber felts by 50% compared to conventional sintering (1200°C for 7200 s), in addition to much reduced sintering cycle and energy consumption.

  7. Spark Plasma Sintered AlN-BN Composites and Its Thermal Conductivity

    NARCIS (Netherlands)

    Zhao Haiyang, [No Value; Wang Weimin, [No Value; Wang Hao, [No Value; Fu Zhengyi, [No Value

    2008-01-01

    A series of samples of hexagonal boron nitride-aluminum nitride ceramic composites with different amounts of CaF(2) as sintering aid were prepared by spark plasma sintered at 1700-1850 degrees C for 5 min. The addition of CaF(2) effectively lowered the sintering temperature and promoted the

  8. Process for the production of metal nitride sintered bodies and resultant silicon nitride and aluminum nitride sintered bodies

    Science.gov (United States)

    Yajima, S.; Omori, M.; Hayashi, J.; Kayano, H.; Hamano, M.

    1983-01-01

    A process for the manufacture of metal nitride sintered bodies, in particular, a process in which a mixture of metal nitrite powders is shaped and heated together with a binding agent is described. Of the metal nitrides Si3N4 and AIN were used especially frequently because of their excellent properties at high temperatures. The goal is to produce a process for metal nitride sintered bodies with high strength, high corrosion resistance, thermal shock resistance, thermal shock resistance, and avoidance of previously known faults.

  9. Demonstration of the Coagulation and Diffusion of Homemade Slime Prepared under Acidic Conditions without Borate

    Science.gov (United States)

    Isokawa, Naho; Fueda, Kazuki; Miyagawa, Korin; Kanno, Kenichi

    2015-01-01

    Poly(vinyl alcohol) (PVA) precipitates in many kinds of aqueous salt solutions. While sodium sulfate, a coagulant for PVA fiber, precipitates PVA to yield a white rigid gel, coagulation of PVA with aluminum sulfate, a coagulant for water treatment, yields a slime-like viscoelastic fluid. One type of homemade slime is prepared under basic…

  10. Cow milk coagulation: process description, variation factors and evaluation methodologies. A review

    Directory of Open Access Journals (Sweden)

    Troch, T.

    2017-01-01

    Full Text Available Introduction. For dairy producers who want to transform their milk, the ability of milk to coagulate is an important parameter. It makes it possible to transform milk into cheese. Therefore, it is necessary to understand the coagulation process and the techniques to measure it in order to achieve the best transformation performance. The objective of this review is to describe the milk coagulation process, the factors influencing it and the methods for measuring the coagulation of milk at lab level. Literature. The processing of milk into cheese involves three steps: coagulation, dewatering and refining. Coagulation is a key step which involves the use of rennet and depends on several parameters (pH, calcium content, temperature, etc.. Some milks never coagulate. To measure the coagulation ability of milk and identify different parameters in milk coagulation properties, the Formagraph, the computerized renneting meter and the Optigraph have been developed (reference methods. Equations have been developed using infrared spectrometry to predict the parameters obtained by the reference methods. Conclusions. The milk coagulation mechanism is known. However, the issue of non-coagulating milk persists and represents a real challenge in terms of yield. The use of infrared is a faster alternative to reference methods that measure the coagulation properties of milk, but still requires an improvement in prediction equations.

  11. 21 CFR 878.4400 - Electrosurgical cutting and coagulation device and accessories.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Electrosurgical cutting and coagulation device and....4400 Electrosurgical cutting and coagulation device and accessories. (a) Identification. An electrosurgical cutting and coagulation device and accessories is a device intended to remove tissue and control...

  12. 21 CFR 864.5425 - Multipurpose system for in vitro coagulation studies.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Multipurpose system for in vitro coagulation... Hematology Devices § 864.5425 Multipurpose system for in vitro coagulation studies. (a) Identification. A multipurpose system for in vitro coagulation studies is a device consisting of one automated or semiautomated...

  13. Coagulation profile of children with sickle cell anemia in steady state ...

    African Journals Online (AJOL)

    Background: Sickle cell anemia is associated with a hypercoagulable state that may lead to alterations in a coagulation profile. Measurements of coagulation factors are known to have some predictive value for clinical outcome. Objectives: To determine the coagulation profile of children with SCA in steady state and crisis ...

  14. Optimization of coagulation-flocculation process for pastas industry ...

    African Journals Online (AJOL)

    The goal of this study was to characterize and then optimize the treatment process of effluent generated from couscous and pasta industry. The crude effluent is characterized by a high level of organic concentration (from 2269 to 4383 mg/l). The optimization of coagulation-flocculation process was then performed to ...

  15. Effect of cyanobacterial peptides and proteins on coagulation of kaolinite

    Czech Academy of Sciences Publication Activity Database

    Novotná, Kateřina; Barešová, Magdalena; Čermáková, Lenka; Načeradská, Jana; Pivokonský, Martin

    2016-01-01

    Roč. 6, č. 2 (2016), s. 83-89 ISSN 1805-0174 Institutional support: RVO:67985874 Keywords : cellular organic matter * coagulation * complex formation * Microcystis aeruginosa * water treatment Subject RIV: DA - Hydrology ; Limnology http://www.ejes.cz/index.php/ejes/article/view/271/123

  16. Electrosurgical device for both mechanical cutting and coagulation of bleeding

    Science.gov (United States)

    Doss, J.D.; McCabe, C.W.

    1985-02-08

    Bipolar electrical coagulation of tissue using radiofrequency energy is combined with the functions of conventional surgical pressure tissue cutting instruments without significant modification thereof in a single instrument with the result that a surgeon can perform both procedures without having to redirect his attention from the area of the surgery. 4 figs.

  17. Coagulation Factors Level in Fresh Frozen Plasma in Rwanda ...

    African Journals Online (AJOL)

    Coagulation Factors Level in Fresh Frozen Plasma in Rwanda. ... Factor X, Von Willbrand Factor, Protein C and Antithrombin decreased from baseline up to three months and then Factor VIII, Factor IX, Factor XI, Factor XII and Protein S, remained constant from baseline up to one month and decreased up to three months.

  18. Mathematical modelling in blood coagulation : simulation and parameter estimation

    NARCIS (Netherlands)

    W.J.H. Stortelder (Walter); P.W. Hemker (Piet); H.C. Hemker

    1997-01-01

    textabstractThis paper describes the mathematical modelling of a part of the blood coagulation mechanism. The model includes the activation of factor X by a purified enzyme from Russel's Viper Venom (RVV), factor V and prothrombin, and also comprises the inactivation of the products formed. In this

  19. Coagulation of some humic acid solutions by Moringa oleifera Lam ...

    African Journals Online (AJOL)

    10 g/L) were required to clarify humic acid solutions whereas 0.5 g/L were used to remove 90% of initial turbidity of a surface water. ... (coagulation of both surface water and distilled water containing a suspension of mineral particles) deal mainly with the effect of some ... metals, pesticides, etc.) inside the water [11, 12].

  20. OPTIMIZATION OF FLOCCULATION PROCESS BY MICROBIAL COAGULANT IN RIVER WATER

    Directory of Open Access Journals (Sweden)

    Fatin Nabilah Murad

    2017-12-01

    Full Text Available The existing process of coagulation and flocculation are using chemicals that known as cationic coagulant such as alum, ferric sulfate, calcium oxide, and organic polymers.  Thus, this study concentrates on optimizing of flocculation process by microbial coagulant in river water. Turbidity and suspended solids are the main constraints of river water quality in Malaysia. Hence, a study is proposed to produce microbial coagulants isolated locally for river water treatment. The chosen microbe used as the bioflocculant producer is Aspergillus niger. The parameters to optimization in the flocculation process were pH, bioflocculant dosage and effluent concentration. The research was done in the jar test process and the process parameters for maximum turbidity removal was validated. The highest flocculating activity was obtained on day seven of cultivation in the supernatant. The optimum pH and bioflocculant dosage for an optimize sedimentation process were between 4-5 and 2-3 mL for 0.3 g/L of effluent concentration respectively. The model was validated by using a river water sample from Sg. Pusu and the result showed that the model was acceptable to evaluate the bioflocculation process.

  1. Optimizing bio-coagulants for brewery wastewater treatment using ...

    African Journals Online (AJOL)

    Jar test experiments were employed for the coag-flocculation process and response surface methodology (RSM) optimize the process. A box-Behnken design (BBD) of Design Expert 6.0.8, implementing RSM was used to evaluate the effects and interactions of three factors: coagulant dosage, pH and stirring time on the ...

  2. Blood coagulation in hemophilia A and hemophilia C

    NARCIS (Netherlands)

    Cawthern, K. M.; van 't Veer, C.; Lock, J. B.; DiLorenzo, M. E.; Branda, R. F.; Mann, K. G.

    1998-01-01

    Tissue factor (TF)-induced coagulation was compared in contact pathway suppressed human blood from normal, factor VIII-deficient, and factor XI-deficient donors. The progress of the reaction was analyzed in quenched samples by immunoassay and immunoblotting for fibrinopeptide A (FPA),

  3. Treatability of South African surface waters by enhanced coagulation

    African Journals Online (AJOL)

    2013-06-05

    Jun 5, 2013 ... standard, many South African water treatment managers may need to consider adoption of enhanced coagulation (EC) in the near future to achieve both turbidity and NOM removal. From the study of 4 South African inland waters, this paper demonstrates that UV254 absorbance provides a more accessible ...

  4. coagulation factors level in fresh frozen plasma in rwanda

    African Journals Online (AJOL)

    2014-02-02

    Feb 2, 2014 ... National Centre for Blood Transfusion Division/Kigali-Rwanda, D. Agwata, BSc, MSc, Medical Laboratory Sciences,. Jomo Kenyatta University Of Agriculture and Technology. COAGULATION FACTORS LEVEL IN FRESH FROZEN PLASMA IN RWANDA. S. UWAMUNGU, A. K. NYAMACHE, F. MASAISA, ...

  5. Coagulation and Adsorption Treatment of Printing Ink Wastewater

    Directory of Open Access Journals (Sweden)

    Maja Klančnik

    2015-03-01

    Full Text Available The intention of the study was to improve the efficiency of total organic carbon (TOC and colour removal from the wastewater samples polluted with flexographic printing ink following coagulation treatments with further adsorption onto activated carbons and ground orange peel. The treatment efficiencies were compared to those of further flocculation treatments and of coagulation and adsorption processes individually. Coagulation was a relatively effective single-treatment method, removing 99.7% of the colour and 86.9% of the organic substances (TOC from the printing ink wastewater samples. Further flocculation did not further eliminate organic pollutants, whereas subsequent adsorption with 7 g/l of granular activated carbon further reduced organic substances by 35.1%, and adsorption with 7 g/l of powdered activated carbon further reduced organic substances by 59.3%. Orange peel was an inappropriate adsorbent for wastewater samples with low amounts of pollution, such as water that had been treated by coagulation. However, in highly polluted printing ink wastewater samples, the adsorption treatment with ground orange peel achieved efficiencies comparable to those of the granular activated carbon treatments.

  6. Coagulation changes following traumatic brain injury and shock

    DEFF Research Database (Denmark)

    Sillesen, Martin

    2014-01-01

    In these studies, we have shown that coagulation and innate immunity pathways respond to trauma within minutes. Furthermore, the appearance of dysfunction of platelets as well as activation of the endothelium is rapidly manifested. Interestingly, many of these changes were attenuated by treatment...

  7. Coagulation factor XI vaccination: an alternative strategy to prevent thrombosis.

    Science.gov (United States)

    Zhong, C; Zhang, L; Chen, L; Deng, L; Li, R

    2017-01-01

    Essentials Coagulation Factor (F) XI is a safe target for the development of antithrombotics. We designed an antigen comprising the human FXI catalytic domain and diphtheria toxin T domain. Antigen immunization reduced plasma FXI activity by 54% and prevented thrombosis in mice. FXI vaccination can serve as an effective strategy for thrombosis prevention. Background Coagulation factor XI serves as a signal amplifier in the intrinsic coagulation pathway. Blockade of FXI by mAbs or small-molecule inhibitors inhibits thrombosis without causing severe bleeding, which is an inherent risk of currently available antithrombotic agents. Objectives To design an FXI vaccine and assess its efficacy in inhibiting FXI activity and preventing thrombosis. Methods An FXI antigen was generated by fusing the catalytic domain of human FXI to the C-terminus of the transmembrane domain of diphtheria toxin. The anti-FXI antibody response, plasma FXI activity and antithrombotic efficacy in mice immunized with the FXI antigen were examined. Results The antigen elicited a significant antibody response against mouse FXI, and reduced the plasma FXI activity by 54.0% in mice. FXI vaccination markedly reduced the levels of coagulation and inflammation in a mouse model of inferior vena cava stenosis. Significant protective effects were also observed in mouse models of venous thrombosis and pulmonary embolism. Conclusions Our data demonstrate that FXI vaccination can serve as an effective strategy for thrombosis prevention. © 2016 The Authors. Journal of Thrombosis and Haemostasis published by Wiley Periodicals, Inc. on behalf of International Society on Thrombosis and Haemostasis.

  8. Monitoring of tissue coagulation during thermotherapy using optoacoustic technique

    Energy Technology Data Exchange (ETDEWEB)

    Larin, Kirill V [Center for Biomedical Engineering, University of Texas Medical Branch, Galveston, TX 77555 (United States); Larina, Irina V [Center for Biomedical Engineering, University of Texas Medical Branch, Galveston, TX 77555 (United States); Department of Neuroscience and Cell Biology, University of Texas Medical Branch, Galveston, TX 77555 (United States); Esenaliev, Rinat O [Center for Biomedical Engineering, University of Texas Medical Branch, Galveston, TX 77555 (United States); Department of Neuroscience and Cell Biology, University of Texas Medical Branch, Galveston, TX 77555 (United States); Department of Anesthesiology, University of Texas Medical Branch, Galveston, TX 77555 (United States)

    2005-08-07

    In this paper we have applied the laser optoacoustic technique for real time noninvasive monitoring of thermal damage in tissues. Changes in tissue optical properties during coagulation were detected by measuring and analysing amplitude and temporal characteristics of optoacoustic signals. Coagulation of liver, myocardium and prostate was induced by interstitial continuous wave Nd : YAG laser irradiation of the samples or by conductive heating. Real time detection of thermally-induced changes in optical properties was performed with sensitive wide-band acoustic transducers. Combination of optoacoustic and diffuse reflectance technique was applied for determination of tissue optical properties: effective attenuation, total diffuse reflectance, reduced scattering coefficient and absorption coefficient. The optical properties did not change up to temperature of coagulation (about 53{sup 0}C) and sharply increased during heating up to 70{sup 0}C. Monitoring of the expansion of interstitial coagulation front within freshly excised canine tissues was performed in real time with spatial resolution of about 0.6 mm. The results of our study suggest that this technique can potentially be used for real time precise thermotherapy of malignant and benign lesions at depths of the order of the centimetre.

  9. The coagulation system in endocrine disorders: a narrative review

    NARCIS (Netherlands)

    Squizzato, A.; Gerdes, V. E. A.; Ageno, W.; Büller, H. R.

    2007-01-01

    Endocrine disorders can influence the haemostatic balance. Abnormal coagulation test results have been observed in patients with abnormal hormone levels. Also unprovoked bleeding or thrombotic events have been associated with endocrine disease. The aim of the present review is to summarise the

  10. Production and characterization of water treatment coagulant from ...

    African Journals Online (AJOL)

    Base on high cost in coagulant for treating both domestic and industrial water in the recent time. There is need to identify cheaper and efficient methods of removing contaminant as the demand for clean water increases. A study was carried out to investigate the use of locally sourced Kaolinite clay from Okefomo ...

  11. Whole blood coagulation time, haematocrit, haemoglobin and total ...

    African Journals Online (AJOL)

    The study was carried out to determine the values of whole blood coagulation time (WBCT), haematocrit (HM), haemaglobin (HB) and total protein (TP) of one hundred and eighteen apparently healthy turkeys reared under an extensive management system in Zaria. The mean values for WBCT, HM, HB and TP were 1.12 ...

  12. Challenges in management of Warfarin anti-coagulation in ...

    African Journals Online (AJOL)

    Challenges in management of Warfarin anti-coagulation in advanced HIV/AIDS patients with venous thrombotic events - A case series from a research clinic in rural Kericho, Kenya. ... VTE was diagnosed 52 (1-469) days after ART initiation, and 81.8% of cases were outpatients at presentation. All patients received at least ...

  13. Coagulation for the clinician | Rutmann | South African Journal of ...

    African Journals Online (AJOL)

    The integrity of the circulation is maintained through the provision of a rapid, potent, but tightly localised coagulation response to vascular damage. There is, however, one extraordinary problem in the regulation of haemostasis – blood flows. Normal haemostasis is the ability of the haemostatic system to control activation of ...

  14. Sonoclot evaluation of whole blood coagulation in healthy adult dogs.

    Science.gov (United States)

    Babski, Danielle M; Brainard, Benjamin M; Krimer, Paula M; Ralph, Alan G; Pittman, Jennifer R; Koenig, Amie

    2012-12-01

    To establish a standard protocol for analysis of canine whole blood and generate reference intervals for healthy dogs using the Sonoclot analyzer, and to compare Sonoclot values to standard and viscoelastic coagulation tests. Prospective study. Veterinary University research facility and teaching hospital. Twelve healthy random source dogs and 52 healthy dogs from the general veterinary school population. Blood sampling for viscoelastic coagulation testing. Blood was collected from 12 healthy adult dogs by jugular venipuncture. After a rest period at room temperature of 30, 60, or 120 minutes, 340 μL of citrated blood was added to 20 μL of 0.2 M CaCl(2) in 1 of 2 cuvette types warmed to 37° C. Cuvettes contained a magnetic stir-bar with glass beads (gbACT+) or only a magnetic stir-bar (nonACT). Reference interval samples were collected from 52 healthy adult dogs and analyzed in duplicate. The ACT, CR, and PF were not affected by duration of rest period for either cuvette type. ACT variability was decreased when using gbACT+ cuvettes (P coagulation tests. Sonoclot provides viscoelastic evaluation of canine whole blood coagulation and correlated to several TEG parameters and fibrinogen. A standard protocol and reference intervals were established. © Veterinary Emergency and Critical Care Society 2012.

  15. Action of Nanoparticles on Platelet Activation and Plasmatic Coagulation

    Science.gov (United States)

    Fröhlich, Eleonore

    2016-01-01

    Nanomaterials can get into the blood circulation after injection or by release from implants but also by permeation of the epithelium after oral, respiratory or dermal exposure. Once in the blood, they can affect hemostasis, which is usually not intended. This review addresses effects of biological particles and engineered nanomaterials on hemostasis. The role of platelets and coagulation in normal clotting and the interaction with the immune system are described. Methods to identify effects of nanomaterials on clotting and results from in vitro and in vivo studies are summarized and the role of particle size and surface properties discussed. The literature overview showed that mainly pro-coagulative effects of nanomaterials have been described. In vitro studies suggested stronger effects of smaller than of larger NPs on coagulation and a greater importance of material than of surface charge. For instance, carbon nanotubes, polystyrene particles, and dendrimers inferred with clotting independent from their surface charge. Coating of particles with polyethylene glycol was able to prevent interaction with clotting by some particles, while it had no effect on others and the more recently developed bio-inspired surfaces might help to design coatings for more biocompatible particles. The mainly pro-coagulative action of nanoparticles could present a particular risk for individuals affected by common diseases such as diabetes, cancer, and cardiovascular diseases. Under standardized conditions, in vitro assays using human blood appear to be a suitable tool to study mechanisms of interference with hemostasis and to optimize hemocompatibility of nanomaterials. PMID:26063498

  16. Disseminated intravascular coagulation in malaria: A case report ...

    African Journals Online (AJOL)

    Disseminated intravascular coagulation (DIC) is seen in <5% of patients with severe Plasmodium falciparum malaria and is more common in cerebral malaria. Here, we report the diagnosis and management of a case of severe P. falciparum malaria with DIC. Keywords: Cerebral malaria, cytokine storm, DIC, heparin ...

  17. Evaluation of the effect of advanced coagulation process to optimize ...

    African Journals Online (AJOL)

    Evaluation of the effect of advanced coagulation process to optimize the removal of natural organic matter in water (Case study: drinking water of Mashhad's ... and in addition to giving taste, color and odor to the water, they can intervene in the oxidization and removal of heavy metals such as arsenic, iron and manganese.

  18. Extracellular vesicles in human follicular fluid do not promote coagulation

    NARCIS (Netherlands)

    Franz, Cordula; Böing, Anita N.; Montag, Markus; Strowitzki, Thomas; Markert, Udo R.; Mastenbroek, Sebastiaan; Nieuwland, Rienk; Toth, Bettina

    2016-01-01

    Body fluids contain extracellular vesicles expressing tissue factor on their surface and serve as an additional trigger for coagulation. During the menstrual cycle ovarian tissue restoration is mandatory and it is unknown whether follicular fluid might provide procoagulant substances. Within an

  19. Indigenous plant based coagulants/disinfectants and sand filter ...

    African Journals Online (AJOL)

    An Evaluation of plant- based coagulants and disinfectant-sand filter medium for surface water treatment in Bamenda, Cameroon using bacterial analyses and turbidity were carried out. 100L of very turbid surface water (Turbidity approx. 500NTU) was pretreated with 100 seeds of Moringa oleifera, and further filtered ...

  20. Indigenous plant based coagulants/disinfectants and sand filter ...

    African Journals Online (AJOL)

    Jane

    2011-08-10

    Aug 10, 2011 ... An Evaluation of plant- based coagulants and disinfectant-sand filter medium for surface water treatment in Bamenda, Cameroon using bacterial analyses and turbidity were carried out. 100L of very turbid surface water (Turbidity approx. 500NTU) was pretreated with 100 seeds of Moringa oleifera, and.

  1. Coagulation / flocculation process in the removal of trace metals ...

    African Journals Online (AJOL)

    Attempts were made in this study to examine the effectiveness of polymer addition to coagulation process during treatment of a beverage industrial wastewater to remove some of its trace metals content such as lead, cadmium, total iron, total chromium, nickel and zinc. Experiments were conducted using the standard Jar ...

  2. Blood coagulation and platelet adhesion on polyaniline films.

    Science.gov (United States)

    Humpolíček, Petr; Kuceková, Zdenka; Kašpárková, Věra; Pelková, Jana; Modic, Martina; Junkar, Ita; Trchová, Miroslava; Bober, Patrycja; Stejskal, Jaroslav; Lehocký, Marián

    2015-09-01

    Polyaniline is a promising conducting polymer with still increasing application potential in biomedicine. Its surface modification can be an efficient way how to introduce desired functional groups and to control its properties while keeping the bulk characteristics of the material unchanged. The purpose of the study was to synthetize thin films of pristine conducting polyaniline hydrochloride, non-conducting polyaniline base and polyaniline modified with poly(2-acrylamido-2-methyl-1-propanesulfonic acid) (PAMPSA) and investigate chosen parameters of their hemocompatibility. The modification was performed either by introduction of PAMPSA during the synthesis or by reprotonation of polyaniline base. The polyaniline hydrochloride and polyaniline base had no impact on blood coagulation and platelet adhesion. By contrast, the polyaniline reprotonated with PAMPSA completely hindered coagulation thanks to its interaction with coagulation factors Xa, Va and IIa. The significantly lower platelets adhesion was also found on this surface. Moreover, this film maintains its conductivity at pH of 6, which is an improvement in comparison with standard polyaniline hydrochloride losing most of its conductivity at pH of 4. Polyaniline film with PAMPSA introduced during synthesis had an impact on platelet adhesion but not on coagulation. The combined conductivity, anticoagulation activity, low platelet adhesion and improved conductivity at pH closer to physiological, open up new possibilities for application of polyaniline reprotonated by PAMPSA in blood-contacting devices, such as catheters or blood vessel grafts. Copyright © 2015 Elsevier B.V. All rights reserved.

  3. Laparoscopic off-clamp partial nephrectomy using soft coagulation.

    Science.gov (United States)

    Hongo, Fumiya; Kawauchi, Akihiro; Ueda, Takashi; Fujihara-Iwata, Atsuko; Nakamura, Terukazu; Naya, Yoshio; Kamoi, Kazumi; Okihara, Koji; Miki, Tsuneharu

    2015-08-01

    To assess the effectiveness of soft coagulation in off-clamp laparoscopic partial nephrectomy. A total of 32 patients with renal tumors underwent laparoscopic partial nephrectomy with off-clamp using soft coagulation between May 2012 and September 2013. Tumor resection was carried out using a combination of bipolar forceps and a ball electrode using the soft coagulation system without hilar clamping. The outcomes of these patients were compared with those of 30 patients treated with hilar clamping. This off-clamp procedure was successfully completed in 31 cases. No significant differences were observed in the mean age (60 vs 61 years), sex (male/female; 25/7 vs 20/10), mean RENAL nephrometry score (5.7 vs 5.8), mean body mass index (24.4 vs 23) or tumor size (15 mm vs 16 mm) between the two groups. No significant differences were noted in positive surgical margins (0 vs 0) or blood loss (104 vs 115 cc) as well. In contrast, a significant difference was noted in the total operative time (278 vs 238 min). Serum creatinine percentage changes at 3 months were 6.4 versus 7.3% in the off-clamp and hilum-clamp groups, respectively, which were not significantly different. Off-clamp laparoscopic partial nephrectomy can be safely carried out by using a soft coagulation technique. © 2015 The Japanese Urological Association.

  4. [Examination of the sample centrifugation time for emergency coagulation test].

    Science.gov (United States)

    Watanabe, Yumi; Kawahara, Yoshie; Hanada, Daisuke; Nozawa, Keisuke; Tomoda, Yutaka; Kino, Shuichi

    2012-11-01

    The rapidity of coagulation testing is important for use as appropriate substitution therapy in patients with, or at risk of critical bleeding requiring massive transfusion. Whereas the ordinary method of coagulation testing is known to be slow, in a critically haemorrhaging patient, a rapid turnaround time of coagulation testing becomes indispensable. To find out if coagulation test results will be affected by a shortened centrifugation time, we measured PT (prothrombin time), APTT (activated partial thromboplastin time), FIB (fibrinogen) and PLT (platelet) in plasma, using different centrifugation times (10 min, 5 min, 3 min), and analyzed the measurements. We found that, whereas centrifugation time significantly affected the PLT count in plasma (10 min; 5.17 +/- 3.71 x 10(3)/microl, 5min; 28. +/- 26.9 x 10(3)/microl, 3min; 63.7 x 10(3)/microl), PT(10min; 14.6 +/- 5.76 sec, 5min; 14.7 +/- 5.84 sec, 3min; 14.9 +/- 6.40 sec), APTT (10min; 36.4 +/- 15.9 sec, 5min; 36.8 +/- 16.5 sec, 3min; 34.7 +/- 11.4 sec) and FIB(10min; 361 +/- 134 mg/dl, 5min; 356 +/- 132 mg/dl, 3min; 356 +/- 125 mg/dl) were not affected. These data suggest that shortening centrifugation time will have no significant effect on the value of PT, APTT and FIB, in an emergency situation.

  5. Coagulation and fibrinolysis in hyperparathyroidism secondary to vitamin D deficiency

    NARCIS (Netherlands)

    Elbers, Laura P. B.; Wijnberge, Marije; Meijers, Joost C. M.; Poland, Dennis C. W.; Brandjes, Dees P. M.; Fliers, Eric; Gerdes, Victor E. A.

    2018-01-01

    Abnormal coagulation tests have been observed in patients with primary hyperparathyroidism (HPT) suggesting a prothrombotic effect of parathyroid hormone (PTH). Vitamin D deficiency (VIDD) is the most frequent cause of secondary HPT. Aim of our study was to investigate the influence of HPT secondary

  6. Aversion substance(s) of the rat coagulating glands

    Science.gov (United States)

    Gawienowski, Anthony M.; Berry, Iver J.; Kennelly, James J.

    1982-01-01

    The aversive substance(s) present in adult male urine were not found in castrate rat urine. Removal of the coagulating glands also resulted in a loss of the aversion compounds. The aversion substances were restored to the urine after androgen treatment of the castrate rats.

  7. Effects of coagulation factors and inflammatory cytokines on ...

    African Journals Online (AJOL)

    Purpose: To investigate the effects of coagulation factors and inflammatory cytokines on acute myocardial infarction (AMI) development in patients younger than 60 years. Methods: In this study, 60 patients admitted to The First Affiliated Hospital of Dalian Medical University (Dalian, China) with AMI and 30 other subjects ...

  8. Mutations targeting the coagulation pathway are enriched in brain metastases

    NARCIS (Netherlands)

    Richichi, C. (Cristina); Fornasari, L. (Lorenzo); Melloni, G.E.M. (Giorgio E. M.); Brescia, P. (Paola); Patanè, M. (Monica); Del Bene, M. (Massimiliano); D.A.M. Mustafa (Dana); J.M. Kros (Johan); Pollo, B. (Bianca); Pruneri, G. (Giancarlo); Sciandivasci, A. (Angela); Munzone, E. (Elisabetta); Dimeco, F. (Francesco); Pelicci, P.G. (Pier Giuseppe); Riva, L. (Laura); Pelicci, G. (Giuliana)

    2017-01-01

    textabstractBrain metastases (BMs) are the most common malignancy of the central nervous system. Recently it has been demonstrated that plasminogen activator inhibitor serpins promote brain metastatic colonization, suggesting that mutations in serpins or other members of the coagulation cascade can

  9. Effects of sintering temperature on the density and porosity

    African Journals Online (AJOL)

    2013-03-01

    Mar 1, 2013 ... used as a model system for the investigation of ce- ramic sintering behavior [1, 2]. However, the system ... cially available metal foams are based on aluminium, copper, nickel and metal alloys [4]. ... Zhao et al [9] reported that the porosity of the as- manufactured foam is determined by the density of.

  10. Effect of sintering temperature and heating mode on consolidation of ...

    Indian Academy of Sciences (India)

    ventional vacuum furnace (10. −2 torr). The transverse rupture strength (TRS) samples (31·7 ... testing machine (model: 1195, INSTRON, UK) at a cross- head speed of 0·5 mm/min and SEM of fractured surfaces ... Photographs of 7775 alloy sintered under vacuum at. 590. ◦. C and 630. ◦. C in conventional furnace. where f is ...

  11. Novel sintered ceramic materials incorporated with EAF carbon steel slag

    Science.gov (United States)

    Karayannis, V.; Ntampegliotis, K.; Lamprakopoulos, S.; Papapolymerou, G.; Spiliotis, X.

    2017-01-01

    In the present research, novel sintered clay-based ceramic materials containing electric arc furnace carbon steel slag (EAFC) as a useful admixture were developed and characterized. The environmentally safe management of steel industry waste by-products and their valorization as secondary resources into value-added materials towards circular economy have attracted much attention in the last years. EAF Carbon steel slag in particular, is generated during the manufacture of carbon steel. It is a solid residue mainly composed of rich-in- Fe, Ca and Si compounds. The experimental results show that the beneficial incorporation of lower percentages of EAFC up to 6%wt. into ceramics sintered at 950 °C is attained without significant variations in sintering behavior and physico-mechanical properties. Further heating up to 1100 °C strongly enhances the densification of the ceramic microstructures, thus reducing the porosity and strengthening their mechanical performance. On the other side, in terms of thermal insulation behavior as well as energy consumption savings and production cost alleviation, the optimum sintering temperature appears to be 950 °C.

  12. Effect of sintering temperature and time on the mechanical ...

    Indian Academy of Sciences (India)

    Administrator

    partial sintering of the alloy particles on the cell walls. Pore size and pore interconnectivity are critical factors in porous material for tissue engineering. Micropores are scale to provide pathways for body fluid and nutrient transpor- tation, needed for bone regeneration and growth.25 In addition, these kinds of pores provide ...

  13. Diffusion of silver during sintering in high permittivity COG dielectrics

    NARCIS (Netherlands)

    Mikkenie, R.; Groen, W.A.; Drift, R. van der

    2010-01-01

    To achieve cost reduction in multi-layer ceramic capacitors and actuators, which use a silver-palladium alloy as internal electrode, the trend is to use alloys with the highest silver content possible. This requires ceramic materials which must be sintered at a relative low temperature. Goal is to

  14. Sintering, camber development of layer composites and a new ...

    Indian Academy of Sciences (India)

    Abstract. Zinc–magnesium titanate dielectrics/nickel–zinc–copper ferrite layer composites were prepared by tape- casting technique combined with a uniaxial pressure shaping technique. The sintering and camber development of the composites were investigated. The results show that the difference of shrinkage in the ...

  15. Electrical discharge machining studies on reactive sintered FeAl

    Indian Academy of Sciences (India)

    Electrical discharge machining (EDM) studies on reactive sintered FeAl were carried out with different process parameters. The metal removal rate and tool removal rate were found to increase with the applied pulse on-time. The surface roughness of machined surface also changed with the applied pulse on-time.

  16. Preparation and characterization of solid-state sintered aluminum ...

    Indian Academy of Sciences (India)

    AZO target; ZnAl2O4 spinel; resistivity; AZO thin film. 1. Introduction. Transparent conducting oxides ... (i) low cost, (ii) low growth temperature, (iii) non-toxicity, and (iv) easy adjustment of conductivity by adding ... strate via sputtering, a target with high sintering density is required. In this work, preparation of high quality AZO ...

  17. Sintering, camber development of layer composites and a new ...

    Indian Academy of Sciences (India)

    Home; Journals; Bulletin of Materials Science; Volume 37; Issue 1. Sintering ... To eliminate or decrease the camber, a new method semi-fixed uniaxial pressure technique (SUP) was proposed. ... Department of Materials Science and Engineering, Xi'an University of Science and Technology, Xi'an 710054, P. R. China ...

  18. Sintering Reaction of Pseudoleucite Syenite: Thermodynamic Analysis and Process Evaluation

    Science.gov (United States)

    TAN, Danjun; MA, Hongwen; LI, Ge; LIU, Hao; ZOU, Dan

    On the basis of comprehensive analysis of the modal composition of a pseudoleucite syenite ore sample, collected from the Zijin Hill of Lin County, Shanxi Province, thermodynamic analysis of the pseudoleucite syenite sintering process with sodium carbonate as the additive was carried out. It indicated that when the pseudoleucite syenite was sintered at 760-880°C for 1.0-1.5 h, with sodium carbonate as the additive. The decomposition rate of minerals in the pseudoleucite syenite could reach 97.1%. The thermodynamic calculation shows that it needs to consume Na 2CO 3, i.e., 0.65 t treating per ton pseudoleucite syenite ore and approximately 95% of Na 2CO 3 could be recycled. This process consumes heat energy (2.29-2.48)×10 -6 kJ, corresponding to standard coal 190.97-206.82 kg as the thermal efficiency was 40% and CO 2 emission was 0.77-0.81 t. Compared with the Russian limestone-sintering technique, the natural mineral resources and energy consumptions and greenhouse gas emissions of the soda-sintering technique were reduced by 65%, 63%, and 65%, respectively. It is, therefore, feasible that the procedure suggested in this article could be industrialized providing both economic benefit and environmental conservation.

  19. Effect of sintering temperature and heating mode on consolidation of ...

    Indian Academy of Sciences (India)

    sintering of various Al-based composites. Microwave heat- ing of metallic powders (Al–Cu–Fe) to single phase was first reported by Vauchera et al (2008). To the best of our know- ... insulation also consisted of graphite coated SiC rods. Tem- perature ... Figure 3 compares thermal profile for 7775 aluminum alloy compacts ...

  20. Coal fly ash utilization: low temperature sintering of wall tiles.

    Science.gov (United States)

    Chandra, Navin; Sharma, Priya; Pashkov, G L; Voskresenskaya, E N; Amritphale, S S; Baghel, Narendra S

    2008-01-01

    We present here a study of the sintering of fly ash and its mixture with low alkali pyrophyllite in the presence of sodium hexa meta phosphate (SHMP), a complex activator of sintering, for the purpose of wall tile manufacturing. The sintering of fly ash with SHMP in the temperature range 925-1050 degrees C produces tiles with low impact strength; however, the incremental addition of low alkali pyrophyllite improves impact strength. The impact strength of composites with >or=40% (w/w) pyrophyllite in the fly ash-pyrophyllite mix satisfies the acceptable limit (19.6 J/m) set by the Indian Standards Institute for wall tiles. Increasing the pyrophyllite content results in an increase in the apparent density of tiles, while shrinkage and water absorption decrease. The strength of fly ash tiles is attributed to the formation of a silicophosphate phase; in pyrophyllite rich tiles, it is attributed to the formation of a tridymite-structured T-AlPO(4) phase. Scanning electron micrographs show that the reinforcing rod shaped T-AlPO(4) crystals become more prominent as the pyrophyllite content increases in the sintered tiles.

  1. Constrained Sintering in Fabrication of Solid Oxide Fuel Cells.

    Science.gov (United States)

    Lee, Hae-Weon; Park, Mansoo; Hong, Jongsup; Kim, Hyoungchul; Yoon, Kyung Joong; Son, Ji-Won; Lee, Jong-Ho; Kim, Byung-Kook

    2016-08-09

    Solid oxide fuel cells (SOFCs) are inevitably affected by the tensile stress field imposed by the rigid substrate during constrained sintering, which strongly affects microstructural evolution and flaw generation in the fabrication process and subsequent operation. In the case of sintering a composite cathode, one component acts as a continuous matrix phase while the other acts as a dispersed phase depending upon the initial composition and packing structure. The clustering of dispersed particles in the matrix has significant effects on the final microstructure, and strong rigidity of the clusters covering the entire cathode volume is desirable to obtain stable pore structure. The local constraints developed around the dispersed particles and their clusters effectively suppress generation of major process flaws, and microstructural features such as triple phase boundary and porosity could be readily controlled by adjusting the content and size of the dispersed particles. However, in the fabrication of the dense electrolyte layer via the chemical solution deposition route using slow-sintering nanoparticles dispersed in a sol matrix, the rigidity of the cluster should be minimized for the fine matrix to continuously densify, and special care should be taken in selecting the size of the dispersed particles to optimize the thermodynamic stability criteria of the grain size and film thickness. The principles of constrained sintering presented in this paper could be used as basic guidelines for realizing the ideal microstructure of SOFCs.

  2. Optical properties of CdS sintered film

    Indian Academy of Sciences (India)

    Unknown

    Abstract. Chemical method has been used to prepare cadmium sulphide by using cadmium, hydrochloric acid and H2S. The reflection spectra of covered and uncovered sintered films of CdS have been recorded by 'Hitachi spectrophotometer' over the wavelength range 300–700 nm. The energy band gaps of these films ...

  3. Preparation and Characterization of Sintered Microporous Polymeric Filters

    Directory of Open Access Journals (Sweden)

    Meysam Salari

    2017-09-01

    Full Text Available Nowadays filtration process is increasingly used in various areas such as water purification, food industries, filtering the air dust and other separation applications. In this work, the HDPE microporous filters have been fabricated at different pressure and time conditions via sintering process and then were characterized by different techniques. It can be expected that microstructure and mechanical properties of the samples could be controlled by changing the fabrication parameters like temperature, pressure, time of the process and also by changing the properties of the resin such as powder shape, particle size and rheological properties. In the first step, by using DSC, MFI, rheology test and optical microscope, the most suitable polymeric powder for sintering process was chosen. The sintering temperature was fixed in the vicinity of melting temperature of the used HDPE powder, based on DSC result. In order to evaluate mechanical properties and porosity of the samples, the results obtained from the shear punch test, acetone drop permeability, gas permeability, transition optical microscopy and SEM, have been used; then the effect of pressure and time parameters on the characteristics of the product has been studied. Finally, it was concluded that it is possible to make microporous filters with suitable mechanical properties, using sintering process at controlled pressure and temperature conditions.It can be seen that by increasing time and pressure, on the one hand the mechanical properties of the products increase, and on the other hand, their porosity and the gas permeability of the vents decrease.

  4. Effect of sintering on controlled release profile of diltiazem ...

    African Journals Online (AJOL)

    The study was designed to formulate and evaluate diltiazem hydrochloride wax matrix tablets for controlled release using sintering technique. Granules of diltiazem hydrochloride-wax were prepared by melt granulation technique. This was formed by triturating the drug powder with a melted carnauba wax (drug: wax ratio, ...

  5. The polarising effects in sintered kaolin | D'ujanga | Tanzania ...

    African Journals Online (AJOL)

    The polarizing effects in sintered kaolin samples were analysed in terms of the sample density (or porosity) using direct current (dc) techniques. More porous samples exhibited higher polarizing effects than the less porous ones. The conduction carriers in kaolin samples at room temperature were found to be mainly ...

  6. Electrical discharge machining studies on reactive sintered FeAl

    Indian Academy of Sciences (India)

    Unknown

    MS received 7 November 2005. Abstract. Electrical discharge machining (EDM) studies on reactive sintered FeAl were carried out with differ- ... electric breakdown process spreads at an explosive rate, resulting in the formation of a .... of cutting fluid takes place which would give out a car- bon residue. The visual black layer ...

  7. New membranes made of sintered clay application to crossflow ...

    African Journals Online (AJOL)

    The new mineral membranes made of sintered clay are performed and characterized in terms of porosity, hydraulic resistance, pore diameter and mechanical resistance. It is shown that these membranes can be used as microfiltration membrane. The variations of the filtrate flux as a function of time are measured during the ...

  8. Physical chemistry and modelling of the sintering of actinide oxides

    International Nuclear Information System (INIS)

    Lechelle, Jacques

    2013-01-01

    This report gives a synthesis of the work I have carried out or to which I have numerically contributed to from 1996 up to 2012 in the Department of Plutonium Uranium and minor Actinides in Cadarache CEA Center. Their main goal is the study and the modeling of the sintering process of nuclear fuels which is the unifying thread of this document. Both in order to take into account the physical and chemical features of the actinide bearing oxide material and in order to combine the different transport phenomena leading to sintering, a sub-granular scale model is under development. Extension to a varying chemical composition as well as exchanges with the gaseous phase are foreseen. A simulation on a larger scale (pellet scale) is ongoing in the framework of a PhD thesis. Validation means have been tested with (U,Pu)O 2 material on the scale of the pellet (Small Angle Neutron Diffusion), on the scale of powder granules (X-Ray High Resolution Micro-Tomography) and with CeO 2 at the 'Institut de Chimie Separative' in Marcoule on a single crystal scale (Environmental Scanning Electron Microscope). The required microstructure homogeneity for nuclear fuels has led to a campaign of experimental studies about the role of Cr 2 O 3 as a sintering aid. Whole of these studies improve our understanding of fuel sintering and hence leads to an improved mastering of this process. (author) [fr

  9. Microstructure and properties of sintered mullite developed from ...

    Indian Academy of Sciences (India)

    purpose are clay minerals such as kaolinite, pyrophyllite, si- llimanite group ... racterized in terms of bulk density, apparent porosity, phase .... density at 1650. ◦. C. Gradual removal of open pores with an increase in sintering temperature is the reason for higher den- sification. Formation of higher amount of low density glass.

  10. Synthesis and electrical field-assisted sintering behaviour of yttria ...

    Indian Academy of Sciences (India)

    Synthesis and electrical field-assisted sintering behaviour of yttria-stabilized tetragonal ZrO2 nanopowders by polyacrylamide gel method. XINGHUA SU. ∗. , BENPAN WANG, JIE ZHOU and HAOYU SUN. School of Materials Science and Engineering, Chang'an University, Xi'an 710061, China. MS received 5 May 2015; ...

  11. Effect of increasing lanthanum substitution and the sintering ...

    Indian Academy of Sciences (India)

    Compared with SBTi ceramics and other lanthanide-substituted compositions, the incorporation of La3+ results in clear improvement in properties for SBLT ( ∼ 0.75) with respect to the values of hardness and Young's modulus of the microwave sintered samples (8.8–12.5 and 160–180 GPa) are higher than that for ...

  12. High-level radioactive waste fixation in sintered vitreous matrix

    International Nuclear Information System (INIS)

    Russo, D.O.; Messi de Bernasconi, N.; Audero, M.A.

    1987-01-01

    The safe storage of high-level wastes from fuel elements reprocessing includes, as a first step, the fixation of the same in materials having a good resistance to the leaching in aqueous medium, such as borosilicate glass. As an alternative to the usual method of the molten glasses, a procedure for the sintering of a powdered glass and waste mixture at lower temperatures (600-700 deg C) has been developed, which minimizes the volatilization of active compounds during the process. Two glasses matrices of different composition and characteristics were used, to which the simulated wastes were added in the ratio of a 10% in weight of oxides. Two sintering techniques were employed 1: cold pressing and further sintering; 2: hot pressing and sintering under pressure. The densities were measured, the microstructure of the samples was analyzed and leaching essays were made in distilled water. The pellet's microstructure was observed by means of optical microscopy, by reflection in polished samples and by transparency in thin slices. The presence of crystalline compounds was analyzed by means of x rays and electron microprobe. The results have shown the convenience to continue with hot pressing essays, because a denser product with a higher resistance to the leaching is thus obtained. (M.E.L.) [es

  13. Strain in the mesoscale kinetic Monte Carlo model for sintering

    DEFF Research Database (Denmark)

    Bjørk, Rasmus; Frandsen, Henrik Lund; Tikare, V.

    2014-01-01

    Shrinkage strains measured from microstructural simulations using the mesoscale kinetic Monte Carlo (kMC) model for solid state sintering are discussed. This model represents the microstructure using digitized discrete sites that are either grain or pore sites. The algorithm used to simulate dens...

  14. Optical properties of CdS sintered film

    Indian Academy of Sciences (India)

    Chemical method has been used to prepare cadmium sulphide by using cadmium, hydrochloric acid and H2S. The reflection spectra of covered and uncovered sintered films of CdS have been recorded by 'Hitachi spectrophotometer' over the wavelength range 300–700 nm. The energy band gaps of these films have been ...

  15. Joining of β-SiC by spark plasma sintering

    Czech Academy of Sciences Publication Activity Database

    Grasso, S.; Tatarko, Peter; Rizzo, S.; Porwal, H.; Hu, Ch.; Katoh, Y.; Salvo, M.; Reece, M. J.; Ferraris, M.

    2014-01-01

    Roč. 34, č. 7 (2014), s. 1681-1686 ISSN 0955-2219 EU Projects: European Commission(XE) 264526 - GLACERCO Institutional support: RVO:68081723 Keywords : β-SiC * joining * Spark plasma sintering Subject RIV: JH - Ceramics, Fire-Resistant Materials and Glass Impact factor: 2.947, year: 2014

  16. Binding Mechanisms in Selective Laser Sintering and Selective Laser Melting

    NARCIS (Netherlands)

    Kruth, J.P.; Mercelis, P.; Van Vaerenbergh, J.; van Vaerenbergh, J.; Froyen, L.; Rombouts, M.

    2005-01-01

    Purpose – This paper provides an overview of the different binding mechanisms in selective laser sintering (SLS) and selective laser melting (SLM), thus improving the understanding of these processes. Design/methodology/approach – A classification of SLS/SLM processes was developed, based on the

  17. New developments in laser sintering of diamond cutting disks

    NARCIS (Netherlands)

    Kovalenko, V.; Golovko, L.; Meijer, J.; Anyakin, M.

    2007-01-01

    The analysis of techniques and problems in the fabrication of cutting tools based on super hard composites results in a solution by the application of lasers. The results of systematic study of diamond composites sintering with laser radiation are discussed. A mathematical modeling of the heat

  18. Preparation and characterization of solid-state sintered aluminum ...

    Indian Academy of Sciences (India)

    Preparation and characterization of solid-state sintered aluminum-doped zinc oxide with different alumina contents. YU-HSIEN CHOU. ∗. , J L H CHAU, W L WANG, C S CHEN, S H WANG and C C YANG. Nanopowder and Thin Film Technology Centre, ITRI–South, Industrial Technology Research Institute, Tainan 70955,.

  19. Photoconductive cells from screen-printed and sintered cadmium sulfoselenide

    Czech Academy of Sciences Publication Activity Database

    Franc, Jiří; Nešpůrek, Stanislav

    2008-01-01

    Roč. 25, č. 3 (2008), s. 41-46 ISSN 1356-5362 Institutional research plan: CEZ:AV0Z40400503; CEZ:AV0Z40500505 Keywords : photoconductivity * detectors (circuits) * sintering * pastes Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 0.471, year: 2008

  20. Consolidation of copper and aluminium powders by spark plasma sintering

    Science.gov (United States)

    Saiprasad, M.; Atchayakumar, R.; Thiruppathi, K.; Raghuraman, S.

    2016-09-01

    Processing in the powder metallurgy route has emerged as an economical process for the production of near net shaped components with a wide range of desired mechanical properties suitable for various applications of industrial needs. This research work was conducted with an objective of studying the improvisation of density and hardness of Copper-Aluminium alloy prepared by spark plasma sintering. Cu-Al alloy with a composition of 95% copper and 5% aluminium was prepared by SPS process. SPS is a low voltage, DC pulse current activated, pressure-assisted sintering, which enables sintering at lower temperatures and shorter durations. The combination offered by Cu-Al alloy of high strength and high corrosion resistance results their applications under a wide variety of conditions. The density and hardness of the prepared sample were measured by conducting appropriate tests. Apparently, the values of hardness and density of the specimen prepared by SPS seemed to be better than that of conventional sintering. The experimental procedure, testing methodologies and analysis are presented.