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Sample records for sintered titanium plug

  1. 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.

  2. 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

  3. Spark plasma sintering of titanium aluminide intermetallics and its composites

    Science.gov (United States)

    Aldoshan, Abdelhakim Ahmed

    Titanium aluminide intermetallics are a distinct class of engineering materials having unique properties over conventional titanium alloys. gamma-TiAl compound possesses competitive physical and mechanical properties at elevated temperature applications compared to Ni-based superalloys. gamma-TiAl composite materials exhibit high melting point, low density, high strength and excellent corrosion resistance. Spark plasma sintering (SPS) is one of the powder metallurgy techniques where powder mixture undergoes simultaneous application of uniaxial pressure and pulsed direct current. Unlike other sintering techniques such as hot iso-static pressing and hot pressing, SPS compacts the materials in shorter time (< 10 min) with a lower temperature and leads to highly dense products. Reactive synthesis of titanium aluminide intermetallics is carried out using SPS. Reactive sintering takes place between liquid aluminum and solid titanium. In this work, reactive sintering through SPS was used to fabricate fully densified gamma-TiAl and titanium aluminide composites starting from elemental powders at different sintering temperatures. It was observed that sintering temperature played significant role in the densification of titanium aluminide composites. gamma-TiAl was the predominate phase at different temperatures. The effect of increasing sintering temperature on microhardness, microstructure, yield strength and wear behavior of titanium aluminide was studied. Addition of graphene nanoplatelets to titanium aluminide matrix resulted in change in microhardness. In Ti-Al-graphene composites, a noticeable decrease in coefficient of friction was observed due to the influence of self-lubrication caused by graphene.

  4. Sintering unalloyed titanium in DC electrical abnormal glow discharge

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    Allan Seeber

    2010-03-01

    Full Text Available Powder metallurgy is widely used in the manufacture of components that have complex geometry. The good dimensional control, reduction in manufacturing steps and operating costs which has favored the use of this technique for manufacturing of titanium alloys components. However, the high affinity of this material with oxygen hinders strongly the sintering process. For this, the sintering associated with plasma technology can be considered an alternative technique for the processing of this material. The strict control of sintering atmosphere performed at low pressures and the reactive species present in the plasma environment can help to improve the sintering of this material. The results presented in this paper show a good correlation between the parameters used for the compaction of the samples and the microstructure develop during the plasma sintering of samples. The microstructure of the plasma assisted samples is also affected by the particular configuration used in the plasma reactor.

  5. Characterization and Sintering of Armstrong Process Titanium Powder

    Science.gov (United States)

    Xu, Xiaoyan; Nash, Philip; Mangabhai, Damien

    2017-04-01

    Titanium and titanium alloys have a high strength to weight ratio and good corrosion resistance but also need longer time and have a higher cost on machining. Powder metallurgy offers a viable approach to produce near net-shape complex components with little or no machining. The Armstrong titanium powders are produced by direct reduction of TiCl4 vapor with liquid sodium, a process which has a relatively low cost. This paper presents a systematic research on powder characterization, mechanical properties, and sintering behavior and of Armstrong process powder metallurgy, and also discusses the sodium issue, and the advantages and disadvantages of Armstrong process powders.

  6. Electro sinter forging of titanium disks

    DEFF Research Database (Denmark)

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

    by measuring the electrical resistance during the sintering process [5], since low electrical resistance corresponds to high density. It is, however, necessary to be aware that increased temperature, on the other hand, increases the resistance. SEM micrographs and Computed Tomography (CT) are carried out......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......, up to 10 kA, and the low voltage, 1-2 V, resulting in heat generation in the powder. Figure 1 shows the experimental setup. The punches were made of a conductive material; namely a copper alloy. The die, which has to be electrically insulating, was made of alumina. The ESF process takes 3-4s...

  7. Grain growth in ultrafine titanium powders during sintering

    International Nuclear Information System (INIS)

    Panigrahi, B.B.; Godkhindi, M.M.

    2006-01-01

    Grain growth behaviour of fine (∼3 μm) and attrition milled nanocrystalline (∼32 nm) titanium powers during sintering have been studied. The activation energies of grain growth (Q g ) in fine titanium were found to be 192.9 and 142.4 kJ/mol at lower and higher temperature ranges, respectively. The nanocrystalline titanium showed very low values of Q g (54.6 kJ/mol) at lower temperatures and it increased to 273.2 kJ/mol at higher temperatures. The constant (n) in nano Ti system was found to have unusually very high values of 6.5-8.2. The grain boundary rotation along with the diffusional processes could be the grain growth mechanism in nanocrystalline and in fine titanium powders

  8. High pressure sintering (HP-HT) of diamond powders with titanium and titanium carbide

    International Nuclear Information System (INIS)

    Jaworska, L.

    1999-01-01

    Polycrystalline diamond compacts for cutting tools are mostly manufactured using high pressure sintering (HP-HT). The standard diamond compacts are prepared by diamond powders sintering with metallic binding phase. The first group of metallic binder are metals able to solve carbon - Co, Ni. The second group of metal binders are carbide forming elements - Ti, Cr, W and others. The paper describes high pressure sintering of diamond powder with titanium and nonstoichiometry titanium carbide for cutting tool application. A type of binding phase has the significant influence on microstructure and mechanical properties of diamond compacts. Very homogeneous structure was achieved in case of compacts obtained from metalized diamond where diamond-TiC-diamond connection were predominant. In the case of compacts prepared by mechanical mixing of diamond with titanium powders the obtained structure was nonhomogeneous with titanium carbide clusters. They had more diamond to diamond connections. These compacts compared to the compact made of metallized diamond have greater wear resistance. In the case of the diamond and TiC 0.92 sintering the strong bonding of TiC diamond grains was obtained. The microstructure observations for diamond with 5% wt. Ti and diamond with 5% wt. TiC 0.92 (the initial composition) compacts were performed in transmission microscope. For two type of compacts the strong bonding phase TiC without defects is creating. (author)

  9. The effect of lanthanum boride on the sintering, sintered microstructure and mechanical properties of titanium and titanium alloys

    International Nuclear Information System (INIS)

    Yang, Y.F.; Luo, S.D.; Qian, M.

    2014-01-01

    An addition of ≤0.5 wt% lanthanum boride (LaB 6 ) to powder metallurgy commercially pure Ti (CP-Ti), Ti–6Al–4V and Ti–10V–2Fe–3Al (all in wt%) resulted in improved sintered density, substantial microstructural refinement, and noticeably increased tensile elongation. The addition of LaB 6 led to scavenging of both oxygen (O) and chlorine (Cl) from the titanium powder during sintering, evidenced by the formation of La 2 O 3 and LaCl x O y . The pinning effect of La 2 O 3 , LaCl x O y and TiB inhibited prior-β grain growth and resulted in subsequent smaller α-laths. The formation of nearly equiaxed α-Ti phase is partially attributed to the nucleation effect of α-Ti on TiB. The improved sintered density was caused by B from LaB 6 rather than La, while excessive formation of La 2 O 3 and TiB with an addition of >0.5 wt% LaB 6 resulted in a noticeable decrease in sintered density. The improved tensile elongation with an addition of ≤0.5 wt% LaB 6 was mainly attributed to the scavenging of oxygen by LaB 6 , partially assisted by the improved sintered density. However, an addition of >0.5 wt% LaB 6 led to the formation of large La 2 O 3 aggregates and more brittle TiB whiskers and therefore decreased tensile elongation. Balanced scavenging of O is thus important. The optimal addition of LaB 6 was 0.5 wt% but this may change depending on the powder size of the LaB 6 to be used

  10. Welding of titanium and nickel alloy by combination of explosive welding and spark plasma sintering technologies

    Energy Technology Data Exchange (ETDEWEB)

    Malyutina, Yu. N., E-mail: iuliiamaliutina@gmail.com; Bataev, A. A., E-mail: bataev@adm.nstu.ru; Shevtsova, L. I., E-mail: edeliya2010@mail.ru [Novosibirsk State Technical University, Novosibirsk, 630073 (Russian Federation); Mali, V. I., E-mail: vmali@mail.ru; Anisimov, A. G., E-mail: anis@hydro.nsc.ru [Lavrentyev Institute of Hydrodynamics SB RAS, Novosibirsk, 630090 (Russian Federation)

    2015-10-27

    A possibility of titanium and nickel-based alloys composite materials formation using combination of explosive welding and spark plasma sintering technologies was demonstrated in the current research. An employment of interlayer consisting of copper and tantalum thin plates makes possible to eliminate a contact between metallurgical incompatible titanium and nickel that are susceptible to intermetallic compounds formation during their interaction. By the following spark plasma sintering process the bonding has been received between titanium and titanium alloy VT20 through the thin powder layer of pure titanium that is distinguished by low defectiveness and fine dispersive structure.

  11. Determination of the Darcy permeability of porous media including sintered metal plugs

    Science.gov (United States)

    Frederking, T. H. K.; Hepler, W. A.; Yuan, S. W. K.; Feng, W. F.

    1986-01-01

    Sintered-metal porous plugs with a normal size of the order of 1-10 microns are used to evaluate the Darcy permeability of laminar flow at very small velocities in laminar fluids. Porous media experiment results and data adduced from the literature are noted to support the Darcy law analog for normal fluid convection in the laminar regime. Low temperature results suggest the importance of collecting room temperature data prior to runs at liquid He(4) temperatures. The characteristic length diagram gives a useful picture of the tolerance range encountered with a particular class of porous media.

  12. Effect of sintering temperatures on titanium matrix composites reinforced by ceramic particles

    Energy Technology Data Exchange (ETDEWEB)

    Romero, F.; Amigo, V.; Busquets, D.; Klyatskina, E. [Mechanical and Materials Engineering Department. Polytechnical University of Valencia, Valencia (Spain)

    2005-07-01

    Titanium and titanium composites have a potential use in aerospace and biotechnology industries, and nowadays in others like sports and fashion ones. In this work composite materials, based on titanium matrix reinforced with ceramic particles, have been developed. PM route is used to obtain compact and sintered samples. TiN and TiAl powders, are milled with Ti powder in different volumetric percentages in a ball mill. These mixtures are pressed in a uniaxial press and sintered in a vacuum furnace at different temperatures between 1180 to 1220 deg. C. Porosity of samples is analysed, before and after the sintering process, by Archimedes technique and by image analysis. Mechanical properties and the reinforcement particles influence in the titanium matrix are studied by flexion test in green and sintered states, and by hardness and microhardness tests. Complimentarily, a microstructural analysis is carried out by optical and electron microscopy, and the reactivity between the reinforce particles and titanium matrix are studied. (authors)

  13. The effect of lanthanum boride on the sintering, sintered microstructure and mechanical properties of titanium and titanium alloys

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Y.F. [RMIT University, Centre for Additive Manufacturing, School of Aerospace, Mechanical and Manufacturing Engineering, GPO Box 2476, Melbourne VIC 3001 (Australia); Luo, S.D. [The University of Queensland, School of Mechanical and Mining Engineering, Brisbane, QLD 4072 (Australia); Qian, M., E-mail: ma.qian@rmit.edu.au [RMIT University, Centre for Additive Manufacturing, School of Aerospace, Mechanical and Manufacturing Engineering, GPO Box 2476, Melbourne VIC 3001 (Australia)

    2014-11-17

    An addition of ≤0.5 wt% lanthanum boride (LaB{sub 6}) to powder metallurgy commercially pure Ti (CP-Ti), Ti–6Al–4V and Ti–10V–2Fe–3Al (all in wt%) resulted in improved sintered density, substantial microstructural refinement, and noticeably increased tensile elongation. The addition of LaB{sub 6} led to scavenging of both oxygen (O) and chlorine (Cl) from the titanium powder during sintering, evidenced by the formation of La{sub 2}O{sub 3} and LaCl{sub x}O{sub y}. The pinning effect of La{sub 2}O{sub 3}, LaCl{sub x}O{sub y} and TiB inhibited prior-β grain growth and resulted in subsequent smaller α-laths. The formation of nearly equiaxed α-Ti phase is partially attributed to the nucleation effect of α-Ti on TiB. The improved sintered density was caused by B from LaB{sub 6} rather than La, while excessive formation of La{sub 2}O{sub 3} and TiB with an addition of >0.5 wt% LaB{sub 6} resulted in a noticeable decrease in sintered density. The improved tensile elongation with an addition of ≤0.5 wt% LaB{sub 6} was mainly attributed to the scavenging of oxygen by LaB{sub 6}, partially assisted by the improved sintered density. However, an addition of >0.5 wt% LaB{sub 6} led to the formation of large La{sub 2}O{sub 3} aggregates and more brittle TiB whiskers and therefore decreased tensile elongation. Balanced scavenging of O is thus important. The optimal addition of LaB{sub 6} was 0.5 wt% but this may change depending on the powder size of the LaB{sub 6} to be used.

  14. Effects of Admixed Titanium on Densification of 316L Stainless Steel Powder during Sintering

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    Aslam Muhammad

    2014-07-01

    Full Text Available Effects of admixed titanium on powder water atomized (PWA and powder gas atomized (PGA 316L stainless steel (SS have been investigated in terms of densification. PGA and PWA powders, having different shapes and sizes, were cold pressed and sintered in argon atmosphere at 1300°C. The admixed titanium compacts of PGA and PWA have shown significant effect on densification through formation of intermetallic compound and reducing porosity during sintering process. PWA, having particle size 8 μm, blended with 1wt% titanium has exhibited higher sintered density and shrinkage as compared to gas atomized powder compacts. Improved densification of titanium blended PGA and PWA 316L SS at sintering temperature 1300°C is probably due to enhanced diffusion kinetics resulting from stresses induced by concentration gradient in powder compacts.

  15. Process parameter influence on Electro-sinter-forging (ESF) of titanium discs

    DEFF Research Database (Denmark)

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

    Electro-sinter-forging (ESF) is an innovative sintering process based on the principle of electrical Joule heating. The electrical current is flowing through the powder compact, which is under mechanical pressure. As compared to conventional sintering [1] and spark plasma sintering [2], the main...... advantages are the decreased sintering time and high relative density [3]. Near net-shape components can be manufactured and post-removal processing is limited to surface polishing. The present work is focused on analysing the influence of the main process parameters, namely compacting pressure, sintering...... time and electrical current density, on the final density of a disc sample made from commercially pure titanium powder. The maximum achieved relative density was 94% of the bulk density of pure titanium. The density estimation was carried out by using both Archimedes’ and 3D scanning....

  16. [Study on physical properties of titanium alloy sample fabricated with vacuum-sintered powder metallurgy].

    Science.gov (United States)

    Ding, X; Liang, X; Chao, Y; Han, X

    2000-06-01

    To investigate the physical properties of titanium alloy fabricated with vacuum-sintered powder metallurgy. The titanium powders of three different particle sizes(-160mesh, -200 - +300mesh, -300mesh) were selected, and mixed with copper and aluminum powder in different proportions. Two other groups were made up of titanium powder(-200 - +300mesh) plated with copper and tin. The build-up and, condensation method and a double-direction press with a metal mold were used. The green compacts were sintered at 1000 degrees C for 15 minutes in a vacuum furnace at 0.025 Pa. In the double-direction press, the specimens were compacted at the pressure of 100 MPa, 200 MPa and 300 MPa respectively. Then the linear shrinkage ratio and the opening porosity of the sintered compacts were evaluated respectively. 1. The linear shrinkage ratio of specimens decreased with the increased compacted pressure(P powders at the same compacted pressure(P > 0.05), but that of titanium powder plated with copper and tin was higher than those of other specimens without plating(P powder did not affect the opening porosity at the same compacted pressure(P > 0.05). The composition of titanium-based metal powder mixtures and the compacted pressures affect the physical properties of sintered compacts. Titanium powder plated with copper and tin is compacted and sintered easily, and the physical properties of sintered compacts are greatly improved.

  17. Process parameter influence on Electro-sinter-forging (ESF) of titanium discs

    DEFF Research Database (Denmark)

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

    Electro-sinter-forging (ESF) is a sintering process based on the resistance heating principle, which makes it faster than conventional sintering. The process is investigated as a function of the main process parameters, namely compacting pressure, electrical current density and sintering time....... The present work is focused on analysing the influence of these process parameters on the final density of a disc sample made from commercially pure titanium powder. Applying the design of experiments (DoE) approach, the electrical current was seen to be of largest influence. The maximum obtained density...

  18. A Modified Porous Titanium Sheet Prepared by Plasma-Activated Sintering for Biomedical Applications

    Directory of Open Access Journals (Sweden)

    Yukimichi Tamaki

    2010-01-01

    Full Text Available This study aimed to develop a contamination-free porous titanium scaffold by a plasma-activated sintering within an originally developed TiN-coated graphite mold. The surface of porous titanium sheet with or without a coated graphite mold was characterized. The cell adhesion property of porous titanium sheet was also evaluated in this study. The peak of TiC was detected on the titanium sheet processed with the graphite mold without a TiN coating. Since the titanium fiber elements were directly in contact with the carbon graphite mold during processing, surface contamination was unavoidable event in this condition. The TiC peak was not detectable on the titanium sheet processed within the TiN-coated carbon graphite mold. This modified plasma-activated sintering with the TiN-coated graphite mold would be useful to fabricate a contamination-free titanium sheet. The number of adherent cells on the modified titanium sheet was greater than that of the bare titanium plate. Stress fiber formation and the extension of the cells were observed on the titanium sheets. This modified titanium sheet is expected to be a new tissue engineering material in orthopedic bone repair.

  19. Influence of Coke Ratio on the Sintering Behavior of High-Chromium Vanadium-Titanium Magnetite

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    Songtao Yang

    2017-06-01

    Full Text Available High-chromium vanadium and titanium magnetite (HCVTM sinter has poor properties. The coke ratio has an important effect on the behavior of HCVTM sintering as it affects the mineral phases in the high-chromium vanadium and titanium sinter (HCVTS via changing the sintering temperature and atmosphere. In this work, the sintering behavior of HCVTM mixed with varying coke ratios was investigated through sintering pot tests, X-ray diffraction (XRD, gas chromatographic analysis, and mineral phase analysis. The results show that, with the increase of the coke ratio from 4.0% to 6.0%, leading to the increase of the combustion ratio of the flue gas, the vertical sintering rate and sinter productivity decrease. Meanwhile, with the change of the coke ratio, the content of magnetite, silicate, and perovskite increase, while the hematite and calcium ferrite decrease. In addition, the tumble strength and reduction ability of HCVTS decrease, and its degradation strength increase. It was found that the appropriate coke ratio for the sintering process was 5.0 wt %.

  20. The Balance of Titanium and Vanadium in the Blast Furnace with the Use of Sinter Containing a Titanium-Vanadium-Magnetite Concentrate

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    Budzik, R.

    2007-01-01

    Full Text Available The investigation concerned the use of sinter containing a titanium-vanadium-magnetite concentrate for the production of pig iron. Sinter containing 0,46 to 0,51 % TiO2 and 0,056 to 0,060 % vanadium was used for pig iron production in the blast furnace. Introducing 200 kg of this concentrate to the1 Mg sinter mix did not cause any deterioration of sinter quality.

  1. 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

  2. An Investigation of Sintering Parameters on Titanium Powder for Electron Beam Melting Processing Optimization

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    Philipp Drescher

    2016-12-01

    Full Text Available Selective electron beam melting (SEBM is a relatively new additive manufacturing technology for metallic materials. Specific to this technology is the sintering of the metal powder prior to the melting process. The sintering process has disadvantages for post-processing. The post-processing of parts produced by SEBM typically involves the removal of semi-sintered powder through the use of a powder blasting system. Furthermore, the sintering of large areas before melting decreases productivity. Current investigations are aimed at improving the sintering process in order to achieve better productivity, geometric accuracy, and resolution. In this study, the focus lies on the modification of the sintering process. In order to investigate and improve the sintering process, highly porous titanium test specimens with various scan speeds were built. The aim of this study was to decrease build time with comparable mechanical properties of the components and to remove the residual powder more easily after a build. By only sintering the area in which the melt pool for the components is created, an average productivity improvement of approx. 20% was achieved. Tensile tests were carried out, and the measured mechanical properties show comparatively or slightly improved values compared with the reference.

  3. An Investigation of Sintering Parameters on Titanium Powder for Electron Beam Melting Processing Optimization.

    Science.gov (United States)

    Drescher, Philipp; Sarhan, Mohamed; Seitz, Hermann

    2016-12-01

    Selective electron beam melting (SEBM) is a relatively new additive manufacturing technology for metallic materials. Specific to this technology is the sintering of the metal powder prior to the melting process. The sintering process has disadvantages for post-processing. The post-processing of parts produced by SEBM typically involves the removal of semi-sintered powder through the use of a powder blasting system. Furthermore, the sintering of large areas before melting decreases productivity. Current investigations are aimed at improving the sintering process in order to achieve better productivity, geometric accuracy, and resolution. In this study, the focus lies on the modification of the sintering process. In order to investigate and improve the sintering process, highly porous titanium test specimens with various scan speeds were built. The aim of this study was to decrease build time with comparable mechanical properties of the components and to remove the residual powder more easily after a build. By only sintering the area in which the melt pool for the components is created, an average productivity improvement of approx. 20% was achieved. Tensile tests were carried out, and the measured mechanical properties show comparatively or slightly improved values compared with the reference.

  4. Processing of pure titanium containing titanium-based reinforcing ceramics additives using spark plasma sintering

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    Mondiu Olayinka DUROWOJU

    2017-06-01

    Full Text Available The densification behaviour, microstructural changes and hardness characteristics during spark plasma sintering of CP-Ti reinforced with TiC, TiN, TiCN and TiB2 were investigated. Commercially pure Ti powders were dry mixed with varied amounts (2.5 and 5 wt. % of the ceramic additives using a T2F Turbula mixer for 5 h and at a speed of 49 rpm. The blended composite powders were then sintered using spark plasma sintering system (model HHPD-25 from FCT Germany at a heating rate of 100oC min-1, dwell time of 5 min and sintering temperature of 950ºC. The sintering of CP-Ti was used as a base study to select the proper spark plasma sintering temperature for full density. Densification was monitored through analysis of the recorded punch displacement and the measured density of the sintered samples using Archimedes method. High densities ranging from 97.8% for 5% TiB2 addition to 99.6% for 5% TiCN addition were achieved at a relatively low temperature of 950°C. Microstructural analyses show a uniform distribution of the additives and finer structure showing their inhibitive effect on grain growth. An improved hardness was observed in all the cases with highest values obtained with TiCN as a result of the combined effect of TiC and TiN. A change in the fracture mode from trans granular to intergranular was also observed.

  5. Xenon thermal behavior in sintered titanium nitride, foreseen inert matrix for GFR

    International Nuclear Information System (INIS)

    Bes, R.

    2010-11-01

    This work concerns the generation IV future nuclear reactors such as gas-cooled fast reactor (GFR) for which refractory materials as titanium nitride (TiN) are needed to surround fuel and act as a fission product diffusion barrier. This study is about Xe thermal behavior in sintered titanium nitride. Microstructure effects on Xe behavior have been studied. In this purpose, several syntheses have been performed using different sintering temperatures and initial powder compositions. Xenon species have been introduced into samples by ionic implantation. Then, samples were annealed in temperature range from 1300 C to 1600 C, these temperatures being the accidental awaited temperature. A transport of xenon towards sample surface has been observed. Transport rate seems to be slow down when increasing sintering temperature. The composition of initial powder and the crystallographic orientation of each considered grain also influence xenon thermal behavior. Xenon release has been correlated with material oxidation during annealing. Xenon bubbles were observed. Their size is proportional with xenon concentration and increases with annealing temperature. Several mechanisms which could explain Xe intragranular mobility in TiN are proposed. In addition with experiments, very low Xe solubility in TiN has been confirmed by ab initio calculations. So, bi-vacancies were found to be the most favoured Xe incorporation sites in this material. (author)

  6. Characterization of the porous structures of the green body and sintered biomedical titanium scaffolds with micro-computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Arifvianto, B., E-mail: b.arifvianto@tudelft.nl; Leeflang, M.A.; Zhou, J.

    2016-11-15

    The present research was aimed at gaining an understanding of the porous structure changes from the green body through water leaching and sintering to titanium scaffolds. Micro-computed tomography (micro-CT) was performed to generate 3D models of titanium scaffold preforms containing carbamide space-holding particles and sintered scaffolds containing macro- and micro-pores. The porosity values and structural parameters were determined by means of image analysis. The result showed that the porosity values, macro-pore sizes, connectivity densities and specific surface areas of the titanium scaffolds sintered at 1200 °C for 3 h did not significantly deviate from those of the green structures with various volume fractions of the space holder. Titanium scaffolds with a maximum specific surface area could be produced with an addition of 60–65 vol% carbamide particles to the matrix powder. The connectivity of pores inside the scaffold increased with rising volume fraction of the space holder. The shrinkage of the scaffolds prepared with > 50 vol% carbamide space holder, occurring during sintering, was caused by the reductions of macro-pore sizes and micro-pore sizes as well as the thickness of struts. In conclusion, the final porous structural characteristics of titanium scaffolds could be estimated from those of the green body. - Highlights: •Porous structures of green body and sintered titanium scaffolds was studied. •Porous structures of both samples were quantitatively characterized with micro-CT. •Porous structures of scaffolds could be controlled from the green body. •Shrinkage mechanisms of titanium scaffolds during sintering was established.

  7. Direct Metal Laser Sintering Titanium Dental Implants: A Review of the Current Literature

    Science.gov (United States)

    Mangano, F.; Chambrone, L.; van Noort, R.; Miller, C.; Hatton, P.; Mangano, C.

    2014-01-01

    Statement of Problem. Direct metal laser sintering (DMLS) is a technology that allows fabrication of complex-shaped objects from powder-based materials, according to a three-dimensional (3D) computer model. With DMLS, it is possible to fabricate titanium dental implants with an inherently porous surface, a key property required of implantation devices. Objective. The aim of this review was to evaluate the evidence for the reliability of DMLS titanium dental implants and their clinical and histologic/histomorphometric outcomes, as well as their mechanical properties. Materials and Methods. Electronic database searches were performed. Inclusion criteria were clinical and radiographic studies, histologic/histomorphometric studies in humans and animals, mechanical evaluations, and in vitro cell culture studies on DMLS titanium implants. Meta-analysis could be performed only for randomized controlled trials (RCTs); to evaluate the methodological quality of observational human studies, the Newcastle-Ottawa scale (NOS) was used. Results. Twenty-seven studies were included in this review. No RCTs were found, and meta-analysis could not be performed. The outcomes of observational human studies were assessed using the NOS: these studies showed medium methodological quality. Conclusions. Several studies have demonstrated the potential for the use of DMLS titanium implants. However, further studies that demonstrate the benefits of DMLS implants over conventional implants are needed. PMID:25525434

  8. Direct metal laser sintering titanium dental implants: a review of the current literature.

    Science.gov (United States)

    Mangano, F; Chambrone, L; van Noort, R; Miller, C; Hatton, P; Mangano, C

    2014-01-01

    Statement of Problem. Direct metal laser sintering (DMLS) is a technology that allows fabrication of complex-shaped objects from powder-based materials, according to a three-dimensional (3D) computer model. With DMLS, it is possible to fabricate titanium dental implants with an inherently porous surface, a key property required of implantation devices. Objective. The aim of this review was to evaluate the evidence for the reliability of DMLS titanium dental implants and their clinical and histologic/histomorphometric outcomes, as well as their mechanical properties. Materials and Methods. Electronic database searches were performed. Inclusion criteria were clinical and radiographic studies, histologic/histomorphometric studies in humans and animals, mechanical evaluations, and in vitro cell culture studies on DMLS titanium implants. Meta-analysis could be performed only for randomized controlled trials (RCTs); to evaluate the methodological quality of observational human studies, the Newcastle-Ottawa scale (NOS) was used. Results. Twenty-seven studies were included in this review. No RCTs were found, and meta-analysis could not be performed. The outcomes of observational human studies were assessed using the NOS: these studies showed medium methodological quality. Conclusions. Several studies have demonstrated the potential for the use of DMLS titanium implants. However, further studies that demonstrate the benefits of DMLS implants over conventional implants are needed.

  9. Direct Metal Laser Sintering Titanium Dental Implants: A Review of the Current Literature

    Directory of Open Access Journals (Sweden)

    F. Mangano

    2014-01-01

    Full Text Available Statement of Problem. Direct metal laser sintering (DMLS is a technology that allows fabrication of complex-shaped objects from powder-based materials, according to a three-dimensional (3D computer model. With DMLS, it is possible to fabricate titanium dental implants with an inherently porous surface, a key property required of implantation devices. Objective. The aim of this review was to evaluate the evidence for the reliability of DMLS titanium dental implants and their clinical and histologic/histomorphometric outcomes, as well as their mechanical properties. Materials and Methods. Electronic database searches were performed. Inclusion criteria were clinical and radiographic studies, histologic/histomorphometric studies in humans and animals, mechanical evaluations, and in vitro cell culture studies on DMLS titanium implants. Meta-analysis could be performed only for randomized controlled trials (RCTs; to evaluate the methodological quality of observational human studies, the Newcastle-Ottawa scale (NOS was used. Results. Twenty-seven studies were included in this review. No RCTs were found, and meta-analysis could not be performed. The outcomes of observational human studies were assessed using the NOS: these studies showed medium methodological quality. Conclusions. Several studies have demonstrated the potential for the use of DMLS titanium implants. However, further studies that demonstrate the benefits of DMLS implants over conventional implants are needed.

  10. Development of microstructure during sintering and aluminium exposure of titanium diboride ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Pettersen, Gunnar

    1997-12-31

    In the production of aluminium, much less energy need be consumed if an inert, wetted cathode is present in the electrolysis cell. Titanium diboride, TiB{sub 2}, is easily wetted and does not readily dissolve in liquid aluminium, but it degrades, probably because aluminium penetrates into it during electrolysis. This degradation is linked to impurities present in the TiB{sub 2} after sintering. This thesis studies the sintering process and how aluminium penetrates into the material. High-purity, high-density TiB{sub 2} compacts were made by hot pressing at 50 MPa in an argon atmosphere at 1790-1960 {sup o}C. Samples were made with different impurity additions. These samples were exposed to liquid aluminium at 980 {sup o}C for 24 hours. All samples were penetrated, but the amount and appearance depended on the sintering aid used. Unlike the other samples, pure TiB{sub 2} was easily penetrated by metallic aluminium because of the open porosity and microcracks of this material. Grain boundary penetration was common among the samples. Differences in penetration behaviour between grain boundaries are probably due to differences in grain boundary energy. But no relation to segregants or boundary misorientation was found. The orientation of grain boundary planes and de-wetting of thin films upon cooling may explain the observed microstructure development. The samples sintered with Ti addition suffered extensive penetration despite their high densities. The grain boundaries of these samples became faceted and contained thicker films of metallic aluminium, presumably because of increased solubility due to iron segregations. All secondary phases present in the grain junctions after sintering, except from the B{sub 4}C phase, reacted with the penetrated aluminium. This did not cause swelling and cracking, as has been suggested by other authors. 101 refs., 48 figs., 7 tabs.

  11. Biocompatibility assessment of spark plasma-sintered alumina-titanium cermets.

    Science.gov (United States)

    Guzman, Rodrigo; Fernandez-García, Elisa; Gutierrez-Gonzalez, Carlos F; Fernandez, Adolfo; Lopez-Lacomba, Jose Luis; Lopez-Esteban, Sonia

    2016-01-01

    Alumina-titanium materials (cermets) of enhanced mechanical properties have been lately developed. In this work, physical properties such as electrical conductivity and the crystalline phases in the bulk material are evaluated. As these new cermets manufactured by spark plasma sintering may have potential application for hard tissue replacements, their biocompatibility needs to be evaluated. Thus, this research aims to study the cytocompatibility of a novel alumina-titanium (25 vol. % Ti) cermet compared to its pure counterpart, the spark plasma sintered alumina. The influence of the particular surface properties (chemical composition, roughness and wettability) on the pre-osteoblastic cell response is also analyzed. The material electrical resistance revealed that this cermet may be machined to any shape by electroerosion. The investigated specimens had a slightly undulated topography, with a roughness pattern that had similar morphology in all orientations (isotropic roughness) and a sub-micrometric average roughness. Differences in skewness that implied valley-like structures in the cermet and predominance of peaks in alumina were found. The cermet presented a higher surface hydrophilicity than alumina. Any cytotoxicity risk associated with the new materials or with the innovative manufacturing methodology was rejected. Proliferation and early-differentiation stages of osteoblasts were statistically improved on the composite. Thus, our results suggest that this new multifunctional cermet could improve current alumina-based biomedical devices for applications such as hip joint replacements. © The Author(s) 2015.

  12. Thermoelectric transport properties of polycrystalline titanium diselenide co-intercalated with nickel and titanium using spark plasma sintering

    Energy Technology Data Exchange (ETDEWEB)

    Holgate, T.C. [Department of Energy Storage and Conversion, Technical University of Denmark, Riso Campus, 4000 Roskilde (Denmark); Zhu, S.; Zhou, M. [Department of Physics and Astronomy, Clemson University, Clemson, SC 29634 (United States); Bangarigadu-Sanasy, S.; Kleinke, H. [Department of Chemistry, University of Waterloo, Waterloo, Ontario, N2L 3G1 (Canada); He, J. [Department of Physics and Astronomy, Clemson University, Clemson, SC 29634 (United States); Tritt, T.M., E-mail: ttritt@clemson.edu [Department of Physics and Astronomy, Clemson University, Clemson, SC 29634 (United States)

    2013-01-15

    Polycrystalline samples of nickel intercalated (0-5%) TiSe{sub 2} were attempted via solid-state reaction in evacuated quartz tubes followed by densification using a spark plasma sintering process. X-ray diffraction data indicated that mixed NiSe{sub 2} and TiSe{sub 2} phases were present after initial synthesis by solid-state reaction, but a pure TiSe{sub 2} phase was present after the spark plasma sintering. While EPMA data reveals the stoichiometry to be near 1:1.8 (Ti:Se) for all samples, comparisons of the measured bulk densities to the theoretical densities suggest that the off stoichiometry is a result of the co-intercalation of both Ni and Ti rather than Se vacancies. Due to the presence of excess Ti (0.085-0.130 per formula) in the van der Waals gap of all the samples, the sensitive electron-hole balance is offset by the additional Ti-3d electrons, leading to an increase in the thermopower (n-type) over pristine, stoichiometric TiSe{sub 2}. The effects of the co-intercalation of both Ni and Ti in TiSe{sub 2} on the structural, thermal, and electrical properties are discussed herein. - Graphical abstract: Co-intercalation of nickel and excess titanium into the van der Waals gap of TiSe{sub 2} via solid state synthesis followed by spark plasma sintering results in a systematic shift in the ratio of hole and electron carrier concentration, which is close to unity for pristine TiSe{sub 2}. This directly affects the electrical transport properties, and as the structural disorder induced by intercalation suppresses the lattice thermal conductivity, co-intercalation is an effective route to enhance the thermoelectric properties of transition metal diselenides. Highlights: Black-Right-Pointing-Pointer Single phase bulk Ni and Ti co-intercalated TiSe{sub 2} samples prepared by spark plasma sintering. Black-Right-Pointing-Pointer Density and X-ray diffraction suggest that the Ni and excess Ti are ordered in the Van der Waals gap. Black-Right-Pointing-Pointer Co

  13. Microstructural Evolution during Pressureless Sintering of Blended Elemental Ti-Al-V-Fe Titanium Alloys from Fine Hydrogenated-Dehydrogenated Titanium Powder

    Directory of Open Access Journals (Sweden)

    Changzhou Yu

    2017-07-01

    Full Text Available A comprehensive study was conducted on microstructural evolution of sintered Ti-Al-V-Fe titanium alloys utilizing very fine hydrogenation-dehydrogenation (HDH titanium powder with a median particle size of 8.84 μm. Both micropores (5–15 μm and macropores (50–200 μm were identified in sintered titanium alloys. Spherical micropores were observed in Ti-6Al-4V sintered with fine Ti at the lowest temperature of 1150 °C. The addition of iron can help reduce microporosity and improve microstructural and compositional homogenization. A theoretical calculation of evaporation based on the Miedema model and Langmuir equation indicates that the evaporation of aluminum could be responsible for the formation of the macropores. Although reasonable densification was achieved at low sintering temperatures (93–96% relative density the samples had poor mechanical properties due mainly to the presence of the macroporosity and the high inherent oxygen content in the as-received fine powders.

  14. Study on Microstructures and Mechanical Properties of Foam Titanium Carbide Ceramics Fabricated by Reaction Sintering Process

    Science.gov (United States)

    Ma, Yana; Bao, Chonggao; Chen, Jie; Song, Suocheng; Han, Longhao

    2018-05-01

    Foam titanium carbide (TiC) ceramics with a three-dimensional network structure were fabricated by the reaction sintering process, in which polyurethane foam was taken as the template, and TiO2 and phenolic resin were used as the reactants. Phase, microstructures and fracture morphologies of foam TiC ceramics were characterized by x-ray diffraction (XRD) and scanning electron microscopy (SEM), respectively. The results show that when the mass ratios of phenolic resin and TiO2 (F/T) are (0.8-1.2): 1, foam TiC ceramics with pure TiC phase can be formed. As the F/T ratios increase, crystal lattice parameters of fabricated foam TiC ceramics become bigger. When the value of F/T decreases from 1.2 to 0.8, grain size of TiC grows larger and microstructures get denser; meanwhile, the compressive strength increases from 0.10 to 1.05 MPa. Additionally, either raising the sintering temperatures or extending holding time can facilitate the completion of the reaction process and increase the compressive strength.

  15. [Effect of sintering gold paste coating on the bonding strength of pure titanium and three low-fusing porcelains].

    Science.gov (United States)

    Zhang, Ya-li; Luo, Xiao-ping; Zhou, Li

    2012-05-01

    To study the effect of sintering gold paste coating of pure titanium on the adhesion of three porcelains following the protocol ISO 9693, and to investigate the titanium-porcelains interfaces. Sixty machined pure titanium samples were prepared in a rectangular shape according to ISO 9693 and divided equally into six groups. Half of the strips were coated with gold paste (Deckgold) and sintered. Three ultra-low-fusing dental porcelains (I: Initial Ti, S: Super porcelain Ti-22, T: TitanKeramik) were fused onto the titanium surfaces. A thin layer of bonding agent was only applied on the surfaces of uncoated gold specimens. The interface of the porcelain and titanium was observed with a field emission scanning electron microscope (FE-SEM) after metallographic preparation and sputtered with a very thin carbon layer of the embedded titanium-porcelain interface. After three-point bending test was performed, optical stereomicroscope was used to characterize the titanium-porcelains adhesion and determine the mode of failure. FE-SEM illustrated intermetallic compounds of Au-Ti formed with some visible microcracks in the gold layer and the interface of gold layer and ceramic. All the uncoated gold titanium-porcelain system showed predominately adhesive fracture at the titanium oxidation, whereas the failure modes in all gold coated systems were cohesive and adhesive, mainly cohesive. The three-point-bending test showed that the bonding strength of GS and GI groups [(37.08 ± 4.32) and (36.20 ± 2.40) MPa] were higher than those in uncoated groups [(31.56 ± 3.74) and (30.88 ± 2.60) MPa, P 0.05). The gold paste intermediate coatings can improve bond strengths of Super porcelain Ti-22 system and Initial Ti system, which have potential applications in clinical fields.

  16. Titanium-hydroxyapatite composites sintered at low temperature for tissue engineering: in vitro cell support and biocompatibility.

    Science.gov (United States)

    Comín, Romina; Cid, Mariana P; Grinschpun, Luciano; Oldani, Carlos; Salvatierra, Nancy A

    2017-04-26

    In clinical orthopedics, a critical problem is the bone tissue loss produced by a disease or injury. The use of composites from titanium and hydroxyapatite for biomedical applications has increased due to the resulting advantageous combination of hydroxyapatite bioactivity and favorable mechanical properties of titanium. Powder metallurgy is a simple and lower-cost method that uses powder from titanium and hydroxyapatite to obtain composites having hydroxyapatite phases in a metallic matrix. However, this method has certain limitations arising from thermal decomposition of hydroxyapatite in the titanium-hydroxyapatite system above 800°C. We obtained a composite from titanium and bovine hydroxyapatite powders sintered at 800°C and evaluated its bioactivity and cytocompatibility according to the ISO 10993 standard. Surface analysis and bioactivity of the composite was evaluated by X-ray diffraction and SEM. MTT assay was carried out to assess cytotoxicity on Vero and NIH3T3 cells. Cell morphology and cell adhesion on the composite surface were analyzed using fluorescence and SEM. We obtained a porous composite with hydroxyapatite particles well integrated in titanium matrix which presented excellent bioactivity. Our data did not reveal any toxicity of titanium-hydroxyapatite composite on Vero or NIH3T3 cells. Moreover, extracts from composite did not affect cell morphology or density. Finally, NIH3T3 cells were capable of adhering to and proliferating on the composite surface. The composite obtained displayed promising biomedical applications through the simple method of powder metallurgy. Additionally, these findings provide an in vitro proof for adequate biocompatibility of titanium-hydroxyapatite composite sintered at 800°C.

  17. Direct metal laser sintering (DMLS) of a customized titanium mesh for prosthetically guided bone regeneration of atrophic maxillary arches.

    Science.gov (United States)

    Ciocca, L; Fantini, M; De Crescenzio, F; Corinaldesi, G; Scotti, R

    2011-11-01

    This study describes a protocol for the direct manufacturing of a customized titanium mesh using CAD-CAM procedures and rapid prototyping to augment maxillary bone and minimize surgery when severe atrophy or post-oncological deformities are present. Titanium mesh and particulate autogenous plus bovine demineralised bone were planned for patient rehabilitation. Bone augmentation planning was performed using the pre-op CT data set in relation to the prosthetic demands, minimizing the bone volume to augment at the minimum necessary for implants. The containment mesh design was used to prototype the 0.6 mm thickness customized titanium mesh, by direct metal laser sintering. The levels of regenerated bone were calculated using the post-op CT data set, through comparison with the pre-op CT data set. The mean vertical height difference of the crestal bone was 2.57 mm, while the mean buccal-palatal dimension of thickness difference was 3.41 mm. All planned implants were positioned after an 8 month healing period using two-step implant surgery, and finally restored with a partial fixed prosthesis. We present a viable and reproducible method to determine the correct bone augmentation prior to implant placement and CAD-CAM to produce a customized direct laser-sintered titanium mesh that can be used for bone regeneration.

  18. Selective Laser Sintering And Melting Of Pristine Titanium And Titanium Ti6Al4V Alloy Powders And Selection Of Chemical Environment For Etching Of Such Materials

    Directory of Open Access Journals (Sweden)

    Dobrzański L.A.

    2015-09-01

    Full Text Available The aim of the investigations described in this article is to present a selective laser sintering and melting technology to fabricate metallic scaffolds made of pristine titanium and titanium Ti6Al4V alloy powders. Titanium scaffolds with different properties and structure were manufactured with this technique using appropriate conditions, notably laser power and laser beam size. The purpose of such elements is to replace the missing pieces of bones, mainly cranial and facial bones in the implantation treatment process. All the samples for the investigations were designed in CAD/CAM (3D MARCARM ENGINEERING AutoFab (Software for Manufacturing Applications software suitably integrated with an SLS/SLM system. Cube-shaped test samples dimensioned 10×10×10 mm were designed for the investigations using a hexagon-shaped base cell. The so designed 3D models were transferred to the machine software and the actual rapid manufacturing process was commenced. The samples produced according to the laser sintering technology were subjected to chemical processing consisting of etching the scaffolds’ surface in different chemical mediums. Etching was carried out to remove the loosely bound powder from the surface of scaffolds, which might detach from their surface during implantation treatment and travel elsewhere in an organism. The scaffolds created were subjected to micro- and spectroscopic examinations

  19. Establishing Antibacterial Multilayer Films on the Surface of Direct Metal Laser Sintered Titanium Primed with Phase-Transited Lysozyme

    Science.gov (United States)

    Guan, Binbin; Wang, Haorong; Xu, Ruiqing; Zheng, Guoying; Yang, Jie; Liu, Zihao; Cao, Man; Wu, Mingyao; Song, Jinhua; Li, Neng; Li, Ting; Cai, Qing; Yang, Xiaoping; Li, Yanqiu; Zhang, Xu

    2016-11-01

    Direct metal laser sintering is a technology that allows the fabrication of titanium (Ti) implants with a functional gradation of porosity and surface roughness according to three-dimensional (3D) computer data. The surface roughness of direct metal laser sintered titanium (DMLS-Ti) implants may provide abundant binding sites for bacteria. Bacterial colonization and subsequent biofilm formation can cause unsatisfactory cell adhesion and implant-related infections. To prevent such infections, a novel phase-transited lysozyme (PTL) was utilized as an initial functional layer to simply and effectively prime DMLS-Ti surfaces for subsequent coating with antibacterial multilayers. The purpose of the present study was to establish a surface with dual biological functionality. The minocycline-loaded polyelectrolyte multilayers of hyaluronic acid (HA) and chitosan (CS) formed via a layer-by-layer (LbL) self-assembly technique on PTL-functionalized DMLS-Ti were designed to inhibit pathogenic microbial infections while allowing the DMLS-Ti itself and the modified coatings to retain acceptable biocompatibility. The experimental results indicate that the DMLS-Ti and the hydrogel treated surfaces can inhibit early bacterial adhesion while completely preserving osteoblast functions. This design is expected to gain considerable interest in the medical field and to have good potential for applications in multifunctional DMLS-Ti implants.

  20. Electrical conductivity of titanium pyrophosphate between 100 and 400 °C: effect of sintering temperature and phosphorus content

    DEFF Research Database (Denmark)

    Lapina, Alberto; Chatzichristodoulou, Christodoulos; Hallinder, Jonathan

    2014-01-01

    The synthesis of titanium pyrophosphate is carried out, and the material is sintered at different temperatures between 370 and 970 °C. Yttrium is added during the synthesis to act as acceptor dopant, but it is mainly present in the material in secondary phases. The conductivity is studied systema...... at 300–390 °C. Slow loss of phosphorus by evaporation over time and changes in the distribution of the amorphous phase during testing are suggested as causes of conductivity degradation above 220 °C.......The synthesis of titanium pyrophosphate is carried out, and the material is sintered at different temperatures between 370 and 970 °C. Yttrium is added during the synthesis to act as acceptor dopant, but it is mainly present in the material in secondary phases. The conductivity is studied...... to an amorphous secondary phase at the grain boundaries, associated with the presence of excess phosphorus in the samples. A contribution to the conductivity by point defects in the bulk may explain the conductivity trend in dry air and the difference in conductivity between oxidizing and reducing atmospheres...

  1. Establishing Antibacterial Multilayer Films on the Surface of Direct Metal Laser Sintered Titanium Primed with Phase-Transited Lysozyme.

    Science.gov (United States)

    Guan, Binbin; Wang, Haorong; Xu, Ruiqing; Zheng, Guoying; Yang, Jie; Liu, Zihao; Cao, Man; Wu, Mingyao; Song, Jinhua; Li, Neng; Li, Ting; Cai, Qing; Yang, Xiaoping; Li, Yanqiu; Zhang, Xu

    2016-11-08

    Direct metal laser sintering is a technology that allows the fabrication of titanium (Ti) implants with a functional gradation of porosity and surface roughness according to three-dimensional (3D) computer data. The surface roughness of direct metal laser sintered titanium (DMLS-Ti) implants may provide abundant binding sites for bacteria. Bacterial colonization and subsequent biofilm formation can cause unsatisfactory cell adhesion and implant-related infections. To prevent such infections, a novel phase-transited lysozyme (PTL) was utilized as an initial functional layer to simply and effectively prime DMLS-Ti surfaces for subsequent coating with antibacterial multilayers. The purpose of the present study was to establish a surface with dual biological functionality. The minocycline-loaded polyelectrolyte multilayers of hyaluronic acid (HA) and chitosan (CS) formed via a layer-by-layer (LbL) self-assembly technique on PTL-functionalized DMLS-Ti were designed to inhibit pathogenic microbial infections while allowing the DMLS-Ti itself and the modified coatings to retain acceptable biocompatibility. The experimental results indicate that the DMLS-Ti and the hydrogel treated surfaces can inhibit early bacterial adhesion while completely preserving osteoblast functions. This design is expected to gain considerable interest in the medical field and to have good potential for applications in multifunctional DMLS-Ti implants.

  2. Effect of carbon and titanium carbide on sintering behaviour of zirconium diboride

    International Nuclear Information System (INIS)

    Mishra, S.K.; Pathak, L.C.

    2008-01-01

    Systematic sintering studies on the ZrB 2 powder were carried out with the addition of carbon (C) in the range of 0 2 . The addition of C also found to inhibit the grain size and fine grained ZrB 2 -C composite could be obtained with high densification. The increased densification with the C addition was due to removal of oxygen impurities on the ZrB 2 powder surfaces that prevented the commonly observed exaggerated grain growth through evaporation condensation of oxide phases during sintering of boride ceramics. At higher percentages of C addition, the densification rates decreased due to increased volume fraction of second phase that acted as diffusion barrier

  3. Reactive Spark Plasma Sintering (SPS) of Nitride Reinforced Titanium Alloy Composites (Postprint)

    Science.gov (United States)

    2014-08-15

    other industrial applications [21–25]. Titanium is widely used in the medical field to replace heart valves , joints, and bones for dental prosthetics due...their wear and fatigue resistance, hard coatings for dental implants and dental surgery tools, tribological orthopedic devices, gears, valves , pumps...their inherent brittleness and inferior fracture toughness [6,10–13]. In contrast, metal matrix composites (MMCs) reinforced with hard precipitates

  4. High energy X-ray diffraction study of a dental ceramics–titanium functional gradient material prepared by field assisted sintering technique

    International Nuclear Information System (INIS)

    Witte, K.; Bodnar, W.; Schell, N.; Lang, H.; Burkel, E.

    2014-01-01

    A functional gradient material with eleven layers composed of a dental ceramics and titanium was successfully consolidated using field assisted sintering technique in a two-step sintering process. High energy X-ray diffraction studies on the gradient were performed at High Energy Material Science beamline at Desy in Hamburg. Phase composition, crystal unit edges and lattice mismatch along the gradient were determined applying Rietveld refinement procedure. Phase analysis revealed that the main crystalline phase present in the gradient is α-Ti. Crystallinity increases stepwisely along the gradient with a decreasing increment between every next layer, following rather the weight fraction of titanium. The crystal unit edge a of titanium remains approximately constant with a value of 2.9686(1) Å, while c is reduced with increasing amount of titanium. In the layer with pure titanium the crystal unit edge c is constant with a value of 4.7174(2) Å. The lattice mismatch leading to an internal stress was calculated over the whole gradient. It was found that the maximal internal stress in titanium embedded in the studied gradient is significantly smaller than its yield strength, which implies that the structure of titanium along the whole gradient is mechanically stable. - Highlights: • High energy XRD studies of dental ceramics–Ti gradient material consolidated by FAST. • Phase composition, crystallinity and lattice parameters are determined. • Crystallinity increases stepwisely along the gradient following weight fraction of Ti. • Lattice mismatch leading to internal stress is calculated over the whole gradient. • Internal stress in α-Ti embedded in the gradient is smaller than its yield strength

  5. Osteoblastic cell response to spark plasma-sintered zirconia/titanium cermets.

    Science.gov (United States)

    Fernandez-Garcia, Elisa; Guillem-Marti, Jordi; Gutierrez-Gonzalez, Carlos F; Fernandez, Adolfo; Ginebra, Maria-Pau; Lopez-Esteban, Sonia

    2015-01-01

    Ceramic/metal composites, cermets, arise from the idea to combine the dissimilar properties in the pure materials. This work aims to study the biocompatibility of new micro-nanostructured 3 Y-TZP/Ti materials with 25, 50 and 75 vol.% Ti, which have been successfully obtained by spark slasma sintering technology, as well as to correlate their surface properties (roughness, wettability and chemical composition) with the osteoblastic cell response. All samples had isotropic and slightly waved microstructure, with sub-micrometric average roughness. Composites with 75 vol.% Ti had the highest surface hydrophilicity. Surface chemical composition of the cermets correlated well with the relative amounts used for their fabrication. A cell viability rate over 80% dismissed any cytotoxicity risk due to manufacturing. Cell adhesion and early differentiation were significantly enhanced on materials containing the nanostructured 3 Y-TZP phase. Proliferation and differentiation of SaOS-2 were significantly improved in their late-stage on the composite with 75 vol.% Ti that, from the osseointegration standpoint, is presented as an excellent biomaterial for bone replacement. Thus, spark plasma sintering is consolidated as a suitable technology for manufacturing nanostructured biomaterials with enhanced bioactivity. © The Author(s) 2014 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav.

  6. Effect of sintering temperature on the microstructure and properties of foamed glass-ceramics prepared from high-titanium blast furnace slag and waste glass

    Science.gov (United States)

    Chen, Chang-hong; Feng, Ke-qin; Zhou, Yu; Zhou, Hong-ling

    2017-08-01

    Foamed glass-ceramics were prepared via a single-step sintering method using high-titanium blast furnace slag and waste glass as the main raw materials The influence of sintering temperature (900-1060°C) on the microstructure and properties of foamed glass-ceramics was studied. The results show that the crystal shape changed from grainy to rod-shaped and finally turned to multiple shapes as the sintering temperature was increased from 900 to 1060°C. With increasing sintering temperature, the average pore size of the foamed glass-ceramics increased and subsequently decreased. By contrast, the compressive strength and the bulk density decreased and subsequently increased. An excessively high temperature, however, induced the coalescence of pores and decreased the compressive strength. The optimal properties, including the highest compressive strength (16.64 MPa) among the investigated samples and a relatively low bulk density (0.83 g/cm3), were attained in the case of the foamed glass-ceramics sintered at 1000°C.

  7. Biomechanical properties of composite compact-porous titanium produced by electric discharge sintering

    Science.gov (United States)

    Minko, D.; Belyavin, K.; Sheleg, V.

    2017-07-01

    The main disadvantage of currently used endosteal implants is their unsatisfactory biostable performance. Under action of functional stress caused by flaws of the design or lower mechanical characteristics the areas of stresses extreme concentration exceeding strength limits of bone tissue appears in the bone surrounding the implant that leads to the tearing away the implant. The problem of specific pressure lowering on the bone and uniform distribution of stress is solved by two ways: the increase of the implant area and the search of implant materials with optimum biomechanical properties. Porous materials of spherical titanium powders have adjustable pore size and large unit surface area, as well as possess high biologic compatibility with living tissue. This allows reduction of the rejection reaction due to a more even stress distribution around the functioning implant. Clinical results show that such implants have more stable physical and chemical properties.

  8. Titanium

    Science.gov (United States)

    Woodruff, Laurel G.; Bedinger, George M.; Piatak, Nadine M.; Schulz, Klaus J.; DeYoung,, John H.; Seal, Robert R.; Bradley, Dwight C.

    2017-12-19

    Titanium is a mineral commodity that is essential to the smooth functioning of modern industrial economies. Most of the titanium produced is refined into titanium dioxide, which has a high refractive index and is thus able to impart a durable white color to paint, paper, plastic, rubber, and wallboard. Because of their high strength-to-weight ratio and corrosion resistance, titanium metal and titanium metal alloys are used in the aerospace industry as well as for welding rod coatings, biological implants, and consumer goods.Ilmenite and rutile are currently the principal titanium-bearing ore minerals, although other minerals, including anatase, perovskite, and titanomagnetite, could have economic importance in the future. Ilmenite is currently being mined from two large magmatic deposits hosted in rocks of Proterozoic-age anorthosite plutonic suites. Most rutile and nearly one-half of the ilmenite produced are from heavy-mineral alluvial, fluvial, and eolian deposits. Titanium-bearing minerals occur in diverse geologic settings, but many of the known deposits are currently subeconomic for titanium because of complications related to the mineralogy or because of the presence of trace contaminants that can compromise the pigment production process.Global production of titanium minerals is currently dominated by Australia, Canada, Norway, and South Africa; additional amounts are produced in Brazil, India, Madagascar, Mozambique, Sierra Leone, and Sri Lanka. The United States accounts for about 4 percent of the total world production of titanium minerals and is heavily dependent on imports of titanium mineral concentrates to meet its domestic needs.Titanium occurs only in silicate or oxide minerals and never in sulfide minerals. Environmental considerations for titanium mining are related to waste rock disposal and the impact of trace constituents on water quality. Because titanium is generally inert in the environment, human health risks from titanium and titanium

  9. Direct laser metal sintering as a new approach to fabrication of an isoelastic functionally graded material for manufacture of porous titanium dental implants.

    Science.gov (United States)

    Traini, T; Mangano, C; Sammons, R L; Mangano, F; Macchi, A; Piattelli, A

    2008-11-01

    This work focuses on a titanium alloy implants incorporating a gradient of porosity, from the inner core to the outer surface, obtained by laser sintering of metal powder. Surface appearance, microstructure, composition, mechanical properties and fractography were evaluated. All the specimens were prepared by a selective laser sintering procedure using a Ti-6Al-4V alloy powder with a particle size of 1-10 microm. The morphological and chemical analyses were performed by SEM and energy dispersive X-ray spectroscopy. The flexure strength was determined by a three-point bend test using a universal testing machine. The surface roughness was investigated using a confocal scanning laser microscope. The surface roughness variation was statistically evaluated by use of a Chi square test. A p value of metal core consisted of columnar beta grains with alpha and beta laths within the grains. The alloy was composed of 90.08% Ti, 5.67% Al and 4.25% V. The Young's modulus of the inner core material was 104+/-7.7 GPa; while that of the outer porous material was 77+/-3.5 GPa. The fracture face showed a dimpled appearance typical of ductile fracture. In conclusion, laser metal sintering proved to be an efficient means of construction of dental implants with a functionally graded material which is better adapted to the elastic properties of the bone. Such implants should minimize stress shielding effects and improve long-term performance.

  10. Topographical cues of direct metal laser sintering titanium surfaces facilitate osteogenic differentiation of bone marrow mesenchymal stem cells through epigenetic regulation.

    Science.gov (United States)

    Zheng, Guoying; Guan, Binbin; Hu, Penghui; Qi, Xingying; Wang, Pingting; Kong, Yu; Liu, Zihao; Gao, Ping; Li, Rui; Zhang, Xu; Wu, Xudong; Sui, Lei

    2018-04-27

    To investigate the role of hierarchical micro/nanoscale topography of direct metal laser sintering (DMLS) titanium surfaces in osteogenic differentiation of bone marrow mesenchymal stem cells (BMSCs), as well as the possible underlying epigenetic mechanism. Three groups of titanium specimens were prepared, including DMLS group, sandblasted, large-grit, acid-etched (SLA) group and smooth titanium (Ti) group. BMSCs were cultured on discs followed by surface characterization. Cell adhesion and proliferation were examined by SEM and CCK-8 assay, while osteogenic-related gene expression was detected by real-time RT-PCR. Immunofluorescence, western blotting and in vivo study were also performed to evaluate the potential for osteogenic induction of materials. In addition, to investigate the underlying epigenetic mechanisms, immunofluorescence and western blotting were performed to evaluate the global level of H3K4me3 during osteogenesis. The H3K4me3 and H3K27me3 levels at the promoter area of the osteogenic gene Runx2 were detected by ChIP assay. The DMLS surface exhibits greater protein adsorption ability and shows better cell adhesion performance than SLA and Ti surfaces. Moreover, both in vitro and in vivo studies demonstrated that the DMLS surface is more favourable for the osteogenic differentiation of BMSCs than SLA and Ti surfaces. Accordingly, osteogenesis-associated gene expression in BMSCs is efficiently induced by a rapid H3K27 demethylation and increase in H3K4me3 levels at gene promoters upon osteogenic differentiation on DMLS titanium surface. Topographical cues of DMLS surfaces have greater potential for the induction of osteogenic differentiation of BMSCs than SLA and Ti surfaces both in vitro and in vivo. A potential epigenetic mechanism is that the appropriate topography allows rapid H3K27 demethylation and an increased H3K4me3 level at the promoter region of osteogenesis-associated genes during the osteogenic differentiation of BMSCs. © 2018 John Wiley

  11. Opportunities in the electrowinning of molten titanium from titanium dioxide

    CSIR Research Space (South Africa)

    Van Vuuren, DS

    2005-10-01

    Full Text Available used, the following forms of titanium are produced: titanium sponge, sintered electrode sponge, powder, molten titanium, electroplated titanium, hydride powder, and vapor-phase depos- ited titanium. Comparing the economics of alter- native...-up for producing titanium via the Kroll process is approximately as follows: ilmenite ($0.27/kg titanium sponge); titanium slag ($0.75/kg titanium sponge); TiCl4 ($3.09/kg titanium sponge); titanium sponge raw materials costs ($5.50/kg titanium sponge); total...

  12. Additive manufacturing technology (direct metal laser sintering) as a novel approach to fabricate functionally graded titanium implants: preliminary investigation of fabrication parameters.

    Science.gov (United States)

    Lin, Wei-Shao; Starr, Thomas L; Harris, Bryan T; Zandinejad, Amirali; Morton, Dean

    2013-01-01

    This article describes the preliminary findings of the mechanical properties of functionally graded titanium with controlled distribution of porosity and a reduced Young's modulus on the basis of a computeraided design (CAD) file, using the rapid-prototyping, direct metal laser sintering (DMLS) technique. Sixty specimens of Ti-6Al-4V were created using a DMLS machine (M270) following the standard for tensile testing of metals. One group was fabricated with only 170 W of laser energy to create fully dense specimens (control group). The remaining specimens all featured an outer fully dense "skin" layer and a partially sintered porous inner "core" region. The outer "skin" of each specimen was scanned at 170 W and set at a thickness of 0.35, 1.00, or 1.50 mm for different specimen groups. The inner "core" of each specimen was scanned at a lower laser power (43 or 85 W). The partially sintered core was clearly visible in all specimens, with somewhat greater porosity with the lower laser power. However, the amount of porosity in the core region was not related to the laser power alone; thinner skin layers resulted in higher porosity for the same power values in the core structure. The lowest Young's modulus achieved, 35 GPa, is close to that of bone and was achieved with a laser power of 43 W and a skin thickness of 0.35 mm, producing a core that comprised 74% of the total volume. Additive manufacturing technology may provide an efficient alternative way to fabricate customized dental implants based on a CAD file with a functionally graded structure that may minimize stress shielding and improve the long-term performance of dental implants.

  13. Tube plug

    International Nuclear Information System (INIS)

    Zafred, P. R.

    1985-01-01

    The tube plug comprises a one piece mechanical plug having one open end and one closed end which is capable of being inserted in a heat exchange tube and internally expanded into contact with the inside surface of the heat exchange tube for preventing flow of a coolant through the heat exchange tube. The tube plug also comprises a groove extending around the outside circumference thereof which has an elastomeric material disposed in the groove for enhancing the seal between the tube plug and the tube

  14. Titanium

    DEFF Research Database (Denmark)

    Fage, Simon W; Muris, Joris; Jakobsen, Stig S

    2016-01-01

    Exposure to titanium (Ti) from implants and from personal care products as nanoparticles (NPs) is common. This article reviews exposure sources, ion release, skin penetration, allergenic effects, and diagnostic possibilities. We conclude that human exposure to Ti mainly derives from dental...... and medical implants, personal care products, and foods. Despite being considered to be highly biocompatible relative to other metals, Ti is released in the presence of biological fluids and tissue, especially under certain circumstances, which seem to be more likely with regard to dental implants. Although...... most of the studies reviewed have important limitations, Ti seems not to penetrate a competent skin barrier, either as pure Ti, alloy, or as Ti oxide NPs. However, there are some indications of Ti penetration through the oral mucosa. We conclude that patch testing with the available Ti preparations...

  15. Reactive Spark Plasma Sintering and Mechanical Properties of Zirconium Diboride–Titanium Diboride Ultrahigh Temperature Ceramic Solid Solutions

    Directory of Open Access Journals (Sweden)

    Karthiselva N. S.

    2016-09-01

    Full Text Available Ultrahigh temperature ceramics (UHTCs such as diborides of zirconium, hafnium tantalum and their composites are considered to be the candidate materials for thermal protection systems of hypersonic vehicles due to their exceptional combination of physical, chemical and mechanical properties. A composite of ZrB2-TiB2 is expected to have better properties. In this study, an attempt has been made to fabricate ZrB2-TiB2 ceramics using mechanically activated elemental powders followed by reactive spark plasma sintering (RSPS at 1400 °C. Microstructure and phase analysis was carried out using X-ray diffractometer (XRD and electron microscopy to understand microstructure evolution. Fracture toughness and hardness were evaluated using indentation methods. Nanoindentation was used to measure elastic modulus. Compressive strength of the composites has been reported.

  16. Microstructural and Mechanical Characterization of a Custom-Built Implant Manufactured in Titanium Alloy by Direct Metal Laser Sintering

    Directory of Open Access Journals (Sweden)

    Maria Aparecida Larosa

    2014-08-01

    Full Text Available Custom-built implants manufacture has always presented difficulties which result in high cost and complex fabrication, mainly due to patients’ anatomical differences. The solution has been to produce prostheses with different sizes and use the one that best suits each patient. Additive manufacturing technology, incorporated into the medical field in the late 80's, has made it possible to obtain solid biomodels facilitating surgical procedures and reducing risks. Furthermore, this technology has been used to produce implants especially designed for a particular patient, with sizes, shapes, and mechanical properties optimized, for different areas of medicine such as craniomaxillofacial surgery. In this work, the microstructural and mechanical properties of Ti6Al4V samples produced by direct metal laser sintering (DMLS are studied. The microstructural and mechanical characterizations have been made by optical and scanning electron microscopy, X-ray diffraction, and microhardness and tensile tests. Samples produced by DMLS have a microstructure constituted by hexagonal α′ martensite with acicular morphology. An average microhardness of 370 HV was obtained and the tensile tests showed ultimate strength of 1172 MPa, yield strength of 957 MPa, and elongation at rupture of 11%.

  17. Titanium carbide-carbon porous nanocomposite materials for radioactive ion beam production: processing, sintering and isotope release properties

    CERN Document Server

    AUTHOR|(CDS)2081922; Stora, Thierry

    2017-01-26

    The Isotope Separator OnLine (ISOL) technique is used at the ISOLDE - Isotope Separator OnLine DEvice facility at CERN, to produce radioactive ion beams for physics research. At CERN protons are accelerated to 1.4 GeV and made to collide with one of two targets located at ISOLDE facility. When the protons collide with the target material, nuclear reactions produce isotopes which are thermalized in the bulk of the target material grains. During irradiation the target is kept at high temperatures (up to 2300 °C) to promote diffusion and effusion of the produced isotopes into an ion source, to produce a radioactive ion beam. Ti-foils targets are currently used at ISOLDE to deliver beams of K, Ca and Sc, however they are operated at temperatures close to their melting point which brings target degradation, through sintering and/or melting which reduces the beam intensities over time. For the past 10 years, nanostructured target materials have been developed and have shown improved release rates of the produced i...

  18. Influence of Sintering Temperature on the Microstructure and Mechanical Properties of In Situ Reinforced Titanium Composites by Inductive Hot Pressing

    Directory of Open Access Journals (Sweden)

    Cristina Arévalo

    2016-11-01

    Full Text Available This research is focused on the influence of processing temperature on titanium matrix composites reinforced through Ti, Al, and B4C reactions. In order to investigate the effect of Ti-Al based intermetallic compounds on the properties of the composites, aluminum powder was incorporated into the starting materials. In this way, in situ TixAly were expected to form as well as TiB and TiC. The specimens were fabricated by the powder metallurgy technique known as inductive hot pressing (iHP, using a temperature range between 900 °C and 1400 °C, at 40 MPa for 5 min. Raising the inductive hot pressing temperature may affect the microstructure and properties of the composites. Consequently, the variations of the reinforcing phases were investigated. X-ray diffraction, microstructural analysis, and mechanical properties (Young’s modulus and hardness of the specimens were carried out to evaluate and determine the significant influence of the processing temperature on the behavior of the composites.

  19. Rotary plug

    International Nuclear Information System (INIS)

    Yamada, Keiji.

    1979-01-01

    Purpose: In a rotating plug of a reactor using a liquid metal as a coolant as in the case of a fbr type reactor, to prevent the ingress of Na vapor into the sliding surface of the rotating plug. Constitution: A rotating plug comprising a large disc covering the upper part of a reactor pressure vessel containing therein a liquid metal and forming surfaces for mounting a shielding device and various other devices, and at least one or more of small discs provided rotatably and eccentrically within said large disc, which is characterized in that an elastic member consisting of bellows and a sealing is interposed between said large disc and said small discs. (Nakamura, S.)

  20. Plugging solution

    Energy Technology Data Exchange (ETDEWEB)

    Sharipov, A U; Yangirov, I Z

    1982-01-01

    A clay-powder, cement, and water-base plugging solution is proposed having reduced solution viscosity characteristics while maintaining tensile strength in cement stone. This solution utilizes silver graphite and its ingredients, by mass weight, are as follows: cement 51.2-54.3%; claypowder 6.06-9.1%; silver graphite 0.24-0.33%; with water making up the remainder.

  1. Plug Power

    Energy Technology Data Exchange (ETDEWEB)

    Marsh, A. [Plug Power Inc., New York, NY (United States)

    2009-07-01

    This presentation described Plug Power's GenDrive hydrogen fuel cell unit that supplies the power needs for folk lift trucks used in high-throughput distribution and high-volume manufacturing operations. The system offers an alternative to lead acid batteries, providing maximum performance at all times during use. The system is particularly useful in the material handling industry, where the revenue generated is based on operator uptime and lift truck productivity. The use of the system allows customers to reduce operational costs and expand valuable floor space by eliminating batteries and associated recharging infrastructure. Fuel cell units also reduce the wear on truck motors. Truck operators can easily and safely refuel at hydrogen fueling stations in 1-5 minutes. GenDrive works with all major OEM lift trucks, making the transition seamless. Commercial customers are investing in this solution to improve their current operations. In 2008, Plug Power sold to Wal-Mart, Bridgestone Firestone and Nestle. Most notably, Central Grocers purchased 220 fuel cell units for a new greenfield distribution center. Plug Power currently has more than 380 systems in operation.

  2. Shielding plugs

    International Nuclear Information System (INIS)

    Makishima, Kenji.

    1986-01-01

    Purpose: In shielding plugs of an LMFBR type reactor, to restrain natural convection of heat in an annular space between a thermal shield layer and a shield shell, to prevent the lowering of heat-insulation performance, and to alleviate a thermal stress in a reactor container and the shield shell. Constitution: A ring-like leaf spring split in the direction of height is disposed in an annular space between a thermal shield layer and a shield shell. In consequence, the space is partitioned in the direction of height and, therefore, if axial temperature conditions and space width are the same and the space is low, the natural convection is hard to occur. Thus the rise of upper surface temperature of the shielding plugs can prevent the lowering of the heat insulation performance which will result in the increment of shielding plug cooling capacity, thereby improving reliability. In the meantime, since there is mounted an earthquake-resisting support, the thermal shield layer will move for a slight gap in case of an earthquake, being supported by the earthquake-resisting support, and the movement of the thermal shield layer is restricted, thereby maintaining integrity without increasing the stroke of the ring-like spring. (Kawakami, Y.)

  3. 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.)

  4. Flash sintering of ceramic materials

    Science.gov (United States)

    Dancer, C. E. J.

    2016-10-01

    During flash sintering, ceramic materials can sinter to high density in a matter of seconds while subjected to electric field and elevated temperature. This process, which occurs at lower furnace temperatures and in shorter times than both conventional ceramic sintering and field-assisted methods such as spark plasma sintering, has the potential to radically reduce the power consumption required for the densification of ceramic materials. This paper reviews the experimental work on flash sintering methods carried out to date, and compares the properties of the materials obtained to those produced by conventional sintering. The flash sintering process is described for oxides of zirconium, yttrium, aluminium, tin, zinc, and titanium; silicon and boron carbide, zirconium diboride, materials for solid oxide fuel applications, ferroelectric materials, and composite materials. While experimental observations have been made on a wide range of materials, understanding of the underlying mechanisms responsible for the onset and latter stages of flash sintering is still elusive. Elements of the proposed theories to explain the observed behaviour include extensive Joule heating throughout the material causing thermal runaway, arrested by the current limitation in the power supply, and the formation of defect avalanches which rapidly and dramatically increase the sample conductivity. Undoubtedly, the flash sintering process is affected by the electric field strength, furnace temperature and current density limit, but also by microstructural features such as the presence of second phase particles or dopants and the particle size in the starting material. While further experimental work and modelling is still required to attain a full understanding capable of predicting the success of the flash sintering process in different materials, the technique non-etheless holds great potential for exceptional control of the ceramic sintering process.

  5. 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

  6. Shielding plug device

    International Nuclear Information System (INIS)

    Orii, Shoichi; Hasegawa, Satoshi; Makishima, Kenji.

    1976-01-01

    Object: To reduce the size of and extend the life of a revolving bearing and facilitate the laying of driving cables and duct lines, this being accomplished by providing plug raising means of a fast breeder on a stationary plug mounting base so as to prevent the shearing force of sodium from acting upon the revolving bearing. Structure: The shield plug means comprises a stationary plug secured to the open end of the reactor container, a rotary plug rotatable with respect to the stationary plug, an annular base formed on top of the stationary plug so as to cover the rotary plug, a bearing secured to the rotary plug edge lower face and upper and lower locking plates. At the time of the rotation of the rotary plug, the upper locking plate is withdrawn, the stationary plug is raised to release the seal structure, and the lower locking plate is inserted between the bearing and stationary plug. In this way, smooth rotation of the rotary plug can be obtained. (Horiuchi, T.)

  7. Reactor vessel sealing plug

    International Nuclear Information System (INIS)

    Dooley, R.A.

    1986-01-01

    This invention relates to an apparatus and method for sealing the cold leg nozzles of a nuclear reactor pressure vessel from a remote location during maintenance and inspection of associated steam generators and pumps while the pressure vessel and refueling canal are filled with water. The apparatus includes a sealing plug for mechanically sealing the cold leg nozzle from the inside of a reactor pressure vessel. The sealing plugs include a primary and a secondary O-ring. An installation tool is suspended within the reactor vessel and carries the sealing plug. The tool telescopes to insert the sealing plug within the cold leg nozzle, and to subsequently remove the plug. Hydraulic means are used to activate the sealing plug, and support means serve to suspend the installation tool within the reactor vessel during installation and removal of the sealing plug

  8. Drill pipe bridge plug

    International Nuclear Information System (INIS)

    Winslow, D.W.; Brisco, D.P.

    1991-01-01

    This patent describes a method of stopping flow of fluid up through a pipe bore of a pipe string in a well. It comprises: lowering a bridge plug apparatus on a work string into the pipe string to a position where the pipe bore is to be closed; communicating the pipe bore below a packer of the bridge plug apparatus through the bridge plug apparatus with a low pressure zone above the packer to permit the fluid to flow up through the bridge plug apparatus; engaging the bridge plug apparatus with an internal upset of the pipe string; while the fluid is flowing up through the bridge plug apparatus, pulling upward on the work string and the bridge plug apparatus and thereby sealing the packer against the pipe bore; isolating the pipe bore below the packer from the low pressure zone above the packer and thereby stopping flow of the fluid up through the pipe bore; disconnecting the work string from the bridge plug apparatus; and maintaining the bridge plug apparatus in engagement with the internal upset and sealed against the pipe bore due to an upward pressure differential applied to the bridge plug apparatus by the fluid contained therebelow

  9. Microstructural comparison of effects of hafnium and titanium additions in spark-plasma-sintered Fe-based oxide-dispersion strengthened alloys

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Yina, E-mail: huangyina1981@hotmail.com [Department of Materials, University of Oxford, Oxford OX1 3PH (United Kingdom); School of Electronic Science & Applied Physics, Hefei University of Technology, Hefei, Anhui 230009 (China); Zhang, Hongtao [Department of Materials, Loughborough University, Leicestershire, LE11 3TU (United Kingdom); Auger, Maria A.; Hong, Zuliang [Department of Materials, University of Oxford, Oxford OX1 3PH (United Kingdom); Ning, Huanpo [School of Engineering of Materials Science, Queen Mary University of London, London, E1 4NS (United Kingdom); Nanoforce Technology Ltd, London, E1 4NS (United Kingdom); Gorley, Michael J. [Department of Materials, University of Oxford, Oxford OX1 3PH (United Kingdom); CCFE, Culham Science Centre, Abingdon, Oxon, OX14 3DB (United Kingdom); Grant, Patrick S. [Department of Materials, University of Oxford, Oxford OX1 3PH (United Kingdom); Reece, Michael J.; Yan, Haixue [School of Engineering of Materials Science, Queen Mary University of London, London, E1 4NS (United Kingdom); Nanoforce Technology Ltd, London, E1 4NS (United Kingdom); Roberts, Steve G. [Department of Materials, University of Oxford, Oxford OX1 3PH (United Kingdom); CCFE, Culham Science Centre, Abingdon, Oxon, OX14 3DB (United Kingdom)

    2017-04-15

    Two oxide dispersion strengthened alloys: 14Cr-0.25Y{sub 2}O{sub 3}-0.22Hf (wt.%) and Fe-14Cr-0.25Y{sub 2}O{sub 3}-0.4Ti (wt.%) were fabricated by mechanical alloying and subsequently consolidated by spark plasma sintering (SPS). Electron backscatter diffraction showed grain sizes in the range 0.5–15 μm in both alloys. Transmission electron microscopy and scanning transmission electron microscopy showed a homogeneous distribution of nano-oxides precipitated during SPS. Using high resolution transmission electron microscopy, energy dispersive X-ray spectroscopy and atom probe tomography, several different oxide phases were found in both alloys, but the majority of dispersoids were Y-Hf-O type in Fe-14Cr-0.25Y{sub 2}O{sub 3}-0.22Hf and Y-Ti-O type in Fe-14Cr-0.25Y{sub 2}O{sub 3}-0.4Ti. There were a variety of orientation relationships between the different dispersoids and the ferritic matrix. Both alloys had dispersoid densities of ∼10{sup 23}/m{sup 3}, with average diameters of 4.3 nm and 3.5 nm in the 0.22Hf and 0.4Ti containing alloys, respectively. Per atom added, Hf (0.07 at.%) is suggested to be more potent than Ti (0.46 at.%) in refining the nano-oxides.

  10. Tube plug removal machine

    International Nuclear Information System (INIS)

    Hawkins, P.J.

    1987-01-01

    In a nuclear steam generator wherein some faulty tubes have been isolated by mechanical plugging, to remove a selected plug without damaging the associated tube, a plug removal machine is used. The machine drills into a plug portion with a tap drill bit having a drill portion a tap portion and a threaded portion, engaging that plug portion with the threaded portion after the drilled hole has been threaded by the tap portion thereof, and removing a portion of the plug in the tube with a counterbore drill bit mounted concentrically about the tap drill bit. A trip pin and trip spline disengage the tap drill bit from the motor. The counterbore drill bit is thereafter self-centered with respect to the tube and plug about the now stationary tap drill bit. After a portion of the plug has been removed by the counterbore drill bit, pulling on the top drill bit by grippers on slots will remove the remaining plug portion from the tube. (author)

  11. Removable pipeline plug

    International Nuclear Information System (INIS)

    Vassalotti, M.; Anastasi, F.

    1984-01-01

    A removable plugging device for a pipeline, and particularly for pressure testing a steam pipeline in a boiling water reactor, wherein an inflatable annular sealing member seals off the pipeline and characterized by radially movable shoes for holding the plug in place, each shoe being pivotally mounted for self-adjusting engagement with even an out-of-round pipeline interior

  12. Retained Herrick Plug

    Directory of Open Access Journals (Sweden)

    Justin B. Hellman

    2018-05-01

    Full Text Available A 79-year-old female with a history of keratoconjunctivitis sicca presented with several years of epiphora of both eyes. Thirteen years earlier, intracanalicular Herrick lacrimal plugs (Lacrimedics, Eastsound, WA, USA had been placed in both eyes to treat her dry eye syndrome. After 13 years the patient felt the epiphora was intolerable and underwent endoscopic dacryocystorhinostomy (DCR of the left, then the right side. Intraoperatively, during the right endoscopic DCR, a Herrick lacrimal plug was found in the common canaliculus into the lacrimal sac. Postoperatively, the patient did well with improved epiphora. The Herrick plug is designed to be intracanalicular, and this case illustrates that the plug can migrate and be retained for many years. Collared punctal plugs have a lower risk of this type of complication.

  13. Plug Load Data

    Data.gov (United States)

    National Aeronautics and Space Administration — We provide MATLAB binary files (.mat) and comma separated values files of data collected from a pilot study of a plug load management system that allows for the...

  14. 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.)

  15. Rotary plug seal

    International Nuclear Information System (INIS)

    Ito, Koji; Abiko, Yoshihiro.

    1981-01-01

    Purpose: To enable fuel exchange even upon failure of regular seals and also to enable safety seal exchange by the detection of the reduction in the contact pressure of a rotary plug seal. Constitution: If one of a pair of regular tube seals for the rotary plug is failed during ordinary operation of a FBR type reactor, the reduction in the contact pressure of the seal to the plug gibbousness is detected by a pressure gauge and a solenoid valve is thereby closed. Thus, a back-up-tube seal provided above or below the tube seal is press-contacted by way of argon gas to the gibbousness to enter into operation state and lubricants are supplied from an oil tank. In such a structure, the back-up-tube seal is operated before the failure of the tube seal to enable to continue the fuel exchange work, as well as safety exchange for the tube seal. (Moriyama, K.)

  16. Core barrel plug

    International Nuclear Information System (INIS)

    Tolino, R.W.; Hopkins, R.J.; Congleton, R.L.; Popalis, C.H.

    1986-01-01

    A plug is described for preventing flow through a port in a core barrel of a pressurized water nuclear reactor which consists of: a substantially cylindrical body formed with a cylindrical portion and a flange and defining a tapered leading open end with the other end being closed by an end plug attached to the flange, the body defining a bore therein extending from the open end to the end plug with the bore having a smaller diameter near the open end than near the end plug, the cylindrical portion having a lip near the open end and being formed with longitudinal slots extending from the open end toward the flange and extending entirely through the thickness of the cylindrical portion, the cylindrical portion having a circumferential first groove on the outer surface thereof located near the forwardmost portion of the cylindrical portion but not in the section of the cylindrical portion that has the slots therein, and a plurality of circumferential second grooves on the outer surface thereof located in the section of the cylindrical portion that has the slots therein, the first and second grooves establishing a seal between the cylindrical portion and the inside surface of the port when the cylindrical portion is expanded, and the flange and the end plug having a passageway defined therein for introducing a fluid into the body; a metal ring disposed in each of the second grooves; a mandrel slidably disposed and captured in the body and capable of being moved toward the open end of the body when the fluid is introduced through the passageway, thereby causing the cylindrical portion to be expanded into contact with the inside surface of the port; and a locking mechanism disposed in the end plug for preventing inadvertent movement of the mandrel

  17. Providing free autopoweroff plugs

    DEFF Research Database (Denmark)

    Jensen, Carsten Lynge; Hansen, Lars Gårn; Fjordbak, Troels

    2012-01-01

    Experimental evidence of the effect of providing households with cheap energy saving technology is sparse. We present results from a field experiment in which autopoweroff plugs were provided free of charge to randomly selected households. We use propensity score matching to find treatment effects...

  18. Fuel rod end plug

    International Nuclear Information System (INIS)

    McGeary, R.K.; Bucher, G.D.

    1989-01-01

    This patent describes an end plug for welded disposition within the end of a tube. It comprises a circumferentially extending, axially oriented land surface, having a radial extent defined by means of a first predetermined dimension, for disposition within the end of the tube; a circumferentially extending, axially oriented land surface, having a radial extent defined by means of a second predetermined dimension which is greater than the first predetermined dimension, for disposition outside of the end of the tube. The second land surface being disposed upstream of the first land surface; an annularly extending, radially oriented shoulder portion, defined at the downstream end of the second land surface and having a radially inward depth which is greater than the difference defined between the first and second radial dimensions of the first and second land surfaces, for engaging the end of the tube in a butt contact fashion; and annular groove means defined between the upstream end of the first land surface and the shoulder portion of the end plug, for eliminating porosity defects normally developed within a weldment defined between the tube end and the end plug when the end plug is welded within the tube end, and including a conical surface which extends radially outwardly from the innermost radial depth extent of the shoulder portion to the upstream end of the first land surface

  19. Vascular plugs - A key companion to Interventionists - 'Just Plug it'.

    Science.gov (United States)

    Ramakrishnan, Sivasubramanian

    2015-01-01

    Vascular plugs are ideally suited to close extra-cardiac, high flowing vascular communications. The family of vascular plugs has expanded. Vascular plugs in general have a lower profile and the newer variants can be delivered even through a diagnostic catheter. These features make them versatile and easy to use. The Amplatzer vascular plugs are also used for closing intracardiac defects including coronary arterio-venous fistula and paravalvular leakage in an off-label fashion. In this review, the features of currently available vascular plugs are reviewed along with tips and tricks of using them in the cardiac catheterization laboratory. Copyright © 2015. Published by Elsevier B.V.

  20. Titanium Metal Powder Production by the Plasma Quench Process

    Energy Technology Data Exchange (ETDEWEB)

    R. A. Cordes; A. Donaldson

    2000-09-01

    The goals of this project included the scale-up of the titanium hydride production process to a production rate of 50 kg/hr at a purity level of 99+%. This goal was to be achieved by incrementally increasing the production capability of a series of reactor systems. This methodic approach was designed to allow Idaho Titanium Technologies to systematically address the engineering issues associated with plasma system performance, and powder collection system design and performance. With quality powder available, actual fabrication with the titanium hydride was to be pursued. Finally, with a successful titanium production system in place, the production of titanium aluminide was to be pursued by the simultaneously injection of titanium and aluminum precursors into the reactor system. Some significant accomplishments of the project are: A unique and revolutionary torch/reactor capable of withstanding temperatures up to 5000 C with high thermal efficiency has been operated. The dissociation of titanium tetrachloride into titanium powder and HC1 has been demonstrated, and a one-megawatt reactor potentially capable of producing 100 pounds per hour has been built, but not yet operated at the powder level. The removal of residual subchlorides and adsorbed HC1 and the sintering of powder to form solid bodies have been demonstrated. The production system has been operated at production rates up to 40 pounds per hour. Subsequent to the end of the project, Idaho Titanium Technologies demonstrated that titanium hydride powder can indeed be sintered into solid titanium metal at 1500 C without sintering aids.

  1. The valve effect of the carbide interlayer of an electric resistance plug

    International Nuclear Information System (INIS)

    Lakomskii, V.

    1998-01-01

    The welded electric resistance plug (ERP) usually contains a carbide interlayer at the plug-carbon material interface. The interlayer forms during welding the contact metallic alloy with the carbon material when the oxide films of the alloy are reduced on the interface surface by carbon to the formation of carbides and the surface layer of the plug material dissolves carbon to saturation. Subsequently, during solidification of the plug material it forms carbides with the alloy components. The structural composition of the carbide interlayer is determined by the chemical composition of the contact alloy. In alloys developed by the author and his colleagues the carbide forming elements are represented in most cases by silicon and titanium and, less frequently, by chromium and manganese. Therefore, the carbide interlayers in the ERP consisted mainly of silicon and titanium carbides

  2. Reactor vessel sealing plug

    International Nuclear Information System (INIS)

    Dooley, R.A.

    1986-01-01

    An apparatus is described for sealing a cold leg nozzle of a nuclear reactor pressure vessel from a remote location comprising: at least one sealing plug for mechanically sealing the nozzle from the inside of the reactor pressure vessel. The sealing plug includes a plate and a cone assembly having an end part receptive in the nozzle, the plate being axially moveable relative to the cone assembly. The plate and cone assembly have confronting bevelled edges defining an opening therebetween. A primary O-ring is disposed about the opening and is supported on the bevelled edges, the plate being guidably mounted to the cone assembly for movement toward the cone assembly to radially expand the primary O-ring into sealing engagement with the nozzle. A means is included for providing relative movement between the outer plate and the cone assembly

  3. Titanium ; dream new material

    International Nuclear Information System (INIS)

    Lee, Yong Tae; Kim Seung Eon; Heoon, Yong Taek; Jung, Hui Won

    2001-11-01

    The contents of this book are history of Titanium, present situation of Titanium industry, property of Titanium alloy, types of it, development of new alloy of Titanium smelting of Titanium, cast of Titanium and heat treatment of Titanium, Titanium alloy for plane, car parts, biological health care, and sport leisure and daily life, prospect, and Titanium industrial development of Titanium in China.

  4. A plugging solution

    Energy Technology Data Exchange (ETDEWEB)

    Gen, O P; Azhigaliyev, G K; Dodonova, S Ye; Dyaltlova, N M; Novokhatskaya, I D; Ryabova, L I

    1984-01-01

    The purpose of the invention is to increase the durability of cement stone at 150 to 200C. The patent covers a plugging solution which consists of Portlandcement, sand and water. It additionally contains metal organic complexes of nitrylotrimethylphosphonic acid and organosiliconates of alkali or alkaline earth metals with the following component relationship in percent by mass: Portland cement, 42 to 43; sand, 27 to 28; metal organic complexes of nitrylotrimethylphosphonic acid, 0.01 to 1.5; organosiliconates of alkaline or alkaline earthmetals, 0.0025 to 0.375 and water, the remainder.

  5. Structure and characteristics of functional powder composite materials obtained by spark plasma sintering

    Science.gov (United States)

    Oglezneva, S. A.; Kachenyuk, M. N.; Kulmeteva, V. B.; Ogleznev, N. B.

    2017-07-01

    The article describes the results of spark plasma sintering of ceramic materials based on titanium carbide, titanium carbosilicide, ceramic composite materials based on zirconium oxide, strengthened by carbon nanostructures and composite materials of electrotechnical purpose based on copper with addition of carbon structures and titanium carbosilicide. The research shows that the spark plasma sintering can achieve relative density of the material up to 98%. The effect of sintering temperature on the phase composition, density and porosity of the final product has been studied. It was found that with addition of carbon nanostructures the relative density and hardness decrease, but the fracture strength of ZrO2 increases up to times 2. The relative erosion resistance of the electrodes made of composite copper-based powder materials, obtained by spark plasma sintering during electroerosion treatment of tool steel exceeds that parameter of pure copper up to times 15.

  6. Double-plug seismic connector

    International Nuclear Information System (INIS)

    Annoot, I.R.

    1984-01-01

    The double-plug seismic electric connector comprises an elongated insulating body. A male connector plug is at one end of the body and a female connector plug is at the opposite end of the body. Each plug has a pair of male and female contacts. A pair of spaced axial conductors is embedded within the insulating body for interconnecting the opposite male and female contacts. The inner end of a double-wire cable is embedded within the insulating body and each wire inner end is connected to one of the conductors

  7. Grooved tube plug rolls in

    International Nuclear Information System (INIS)

    Krausser, P.

    1991-01-01

    The removable plugs used to date by the Power Generation Group (KWU) of Siemens to seal defective steam generator tubes have a good track record. Their sealing principle is based on the elastic tensioning of three seal disks against the inside wall of the tube. Now a further removable plug is available -a roll-in plug with a metal-coated surface. It is particularly suitable for use in the roller-expanded zone of the tubes at the tube sheet. The plugs can be used in both Siemens-KWU steam generators and in steam generators manufactured in compliance with the guidelines of the ASME Code. (author)

  8. Mechanics Model of Plug Welding

    Science.gov (United States)

    Zuo, Q. K.; Nunes, A. C., Jr.

    2015-01-01

    An analytical model has been developed for the mechanics of friction plug welding. The model accounts for coupling of plastic deformation (material flow) and thermal response (plastic heating). The model predictions of the torque, energy, and pull force on the plug were compared to the data of a recent experiment, and the agreements between predictions and data are encouraging.

  9. On the use of titanium hydride for powder injection moulding of titanium-based alloys

    International Nuclear Information System (INIS)

    Carrenoo-Morelli, E.; Bidaux, J.-E.

    2009-01-01

    Full text: Titanium and titanium-based alloys are excellent materials for a number of engineering applications because of their high strength, lightweight, good corrosion resistance, non magnetic characteristic and biocompatibility. The current processing steps are usually costly, and there is a growing demand for net-shape solutions for manufacturing parts of increasing complexity. Powder injection moulding is becoming a competitive alternative, thanks to the advances in production of good quality base-powders, binders and sintering facilities. Titanium hydride powders, have the attractiveness of being less reactive than fine titanium powders, easier to handle, and cheaper. This paper summarizes recent advances on PIM of titanium and titanium alloys from TiH2 powders, including shape-memory NiTi alloys. (author)

  10. 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)

  11. Borehole Plugging Program. Plugging of ERDA No. 10 drill hole

    International Nuclear Information System (INIS)

    Gulick, C.W. Jr.

    1979-06-01

    A requirement exists to plug exploratory drill holes located in the proposed Waste Isolation Pilot Plant area of Southeastern New Mexico. Sandia Laboratories, in cooperation with the US Army Corps of Engineers, Waterways Experiment Station, Concrete Laboratory, developed pumpable and durable cement grouts. These grouts were successfully used to plug an existing drill hole in the area. Results of this project are presented, along with comments and conclusions

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

    DEFF Research Database (Denmark)

    Cannella, Emanuele; Nielsen, Chris Valentin

    ) process, the main requirement is the electrical current passing through the electrical conducting powder. To obtain this, a closed-die setup with electrical insulating properties was used. Furthermore, the alignment between the compacting punch and die needed to be ensured by pre-aligning or alternatively...... by using an alignment system. The present work is focused on the designing phase of a tool for the electro sinter forging of a disc, made from titanium powder. By applying a pre-alignment system, the setup resulted suitable for this application. A tool design for sintering rings is also showed....

  13. 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

  14. Science of sintering

    International Nuclear Information System (INIS)

    Kuczynski, G.

    1977-01-01

    Although the methods of integration of materials by sintering, have been used since the early history of humanity, the actual understanding of the process involved came only in the last three decades. As in the most human endeavors, the art preceded theory. The comprehension of the elementary processes occuring during sintering comes from the studies of model system. Although the elementary processes occuring during sintering are today quite well understood, the problem of shrinkage of a powder compact which was at the origin of Sintering Science is still far from solved. This is due to the complexity of the internal geometry of the compacts. The recent attempts to apply statistics to this problem, seem to offer some promise

  15. Uranium dioxide. Sintering test

    International Nuclear Information System (INIS)

    Anon.

    Description of a sintering method and of the equipment devoted to uranium dioxide powder caracterization and comparison between different samples. Determination of the curve giving specific volume versus pressure and micrographic examination of a pellet at medium pressure [fr

  16. Kinetics of UO2 sintering

    International Nuclear Information System (INIS)

    Ristic, M.M.

    1962-01-01

    Detailed conclusions related to the UO 2 sintering can be drawn from investigating the kinetics of the sintering process. This report gives an thorough analysis of the the data concerned with sintering available in the literature taking into account the Jander and Arrhenius laws. This analysis completes the study of influence of the O/U ratio and the atmosphere on the sintering. Results presented are fundamentals of future theoretical and experimental work related to characterisation of the UO 2 sintering process

  17. Plug testing and removal tool

    International Nuclear Information System (INIS)

    Baric, T.J.; Kauric, C.E.; Garcia, C.N.

    1987-01-01

    This patent describes an apparatus for testing and removing a plug from an aperture in the cylindrical core barrel wall of a nuclear reactor. The plug has an enlarged head disposed along the wall in a narrow annular access space between the wall and a surrounding cylindrical thermal neutron shield. The apparatus comprises: fixed jaw means; movable jaw means pivotally connected to the fixed jaw means for movement with respect thereto between an open position accommodating reception of the plug head between the fixed and movable jaw means and a closed position for securely gripping the plug head between the fixed and movable jaw means; drive means carried by the fixed jaw means and coupled to the movable jaw means for effecting movement thereof between the open and closed positions thereof; and tensioning means carried by the jaw means for engagement with the core barrel when the jaw means are disposed in gripping engagement with the plug head for exerting on the jaw means and the gripped plug a predetermined force in a direction radially outwardly of the wall. The jaw means and the drive means and the tensioning means all have dimensions radially of the wall substantially less than the radial thickness of the access space to permit insertion into, movement within and removal from the access space

  18. Cranioplasty with individual titanium implants

    Science.gov (United States)

    Mishinov, S.; Stupak, V.; Sadovoy, M.; Mamonova, E.; Koporushko, N.; Larkin, V.; Novokshonov, A.; Dolzhenko, D.; Panchenko, A.; Desyatykh, I.; Krasovsky, I.

    2017-09-01

    Cranioplasty is the second procedure in the history of neurosurgery after trepanation, and it is still relevant despite the development of civilization and progress in medicine. Each cranioplasty operation is unique because there are no two patients with identical defects of the skull bones. The development of Direct Metal Laser Sintering (DMLS) technique opened up the possibility of direct implant printing of titanium, a biocompatible metal used in medicine. This eliminates the need for producing any intermediate products to create the desired implant. We have produced 8 patient-specific titanium implants using this technique for patients who underwent different decompressive cranioectomies associated with bone tumors. Follow-up duration ranged from 6 to 12 months. We observed no implant-related reactions or complications. In all cases of reconstructive neurosurgery we achieved good clinical and aesthetic results. The analysis of the literature and our own experience in three-dimensional modeling, prototyping, and printing suggests that direct laser sintering of titanium is the optimal method to produce biocompatible surgical implants.

  19. Sintering Theory and Practice

    Science.gov (United States)

    German, Randall M.

    1996-01-01

    Although sintering is an essential process in the manufacture of ceramics and certain metals, as well as several other industrial operations, until now, no single book has treated both the background theory and the practical application of this complex and often delicate procedure. In Sintering Theory and Practice, leading researcher and materials engineer Randall M. German presents a comprehensive treatment of this subject that will be of great use to manufacturers and scientists alike. This practical guide to sintering considers the fact that while the bonding process improves strength and other engineering properties of the compacted material, inappropriate methods of control may lead to cracking, distortion, and other defects. It provides a working knowledge of sintering, and shows how to avoid problems while accounting for variables such as particle size, maximum temperature, time at that temperature, and other problems that may cause changes in processing. The book describes the fundamental atomic events that govern the transformation from particles to solid, covers all forms of the sintering process, and provides a summary of many actual production cycles. Building from the ground up, it begins with definitions and progresses to measurement techniques, easing the transition, especially for students, into advanced topics such as single-phase solid-state sintering, microstructure changes, the complications of mixed particles, and pressure-assisted sintering. German draws on some six thousand references to provide a coherent and lucid treatment of the subject, making scientific principles and practical applications accessible to both students and professionals. In the process, he also points out and avoids the pitfalls found in various competing theories, concepts, and mathematical disputes within the field. A unique opportunity to discover what sintering is all about--both in theory and in practice What is sintering? We see the end product of this thermal

  20. 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

  1. 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

  2. Sintering of composite

    International Nuclear Information System (INIS)

    Bordia, R.K.; Scherer, G.W.

    1988-01-01

    Several constitutive laws have been used in the literature to predict the response of sintering bodies under external and internal stress fields. These analyses are based on the assumptions of linear and isotropic behavior. The authors provide a critical examination of these equations and show that some of the available constitutive laws predict a negative Poisson's ratio. These laws have been used to analyze sintering of ceramic matrix composites with rigid inclusions and predict large values of the internal stresses and significant retardation of the densification of composites. Since a negative value of Poisson's ratio has never been observed in sinter - forging experiments, the authors conclude that either the stresses are small (as predicted by the constitutive laws with positive Poisson's ratio) or the basic assumption of linearity and isotropy used in all the analyses is incorrect. Finally, the authors discuss some phenomena that could be important in understanding the densification of ceramic matrix composites

  3. Optimization of process parameters for spark plasma sintering of nano structured SAF 2205 composite

    Directory of Open Access Journals (Sweden)

    Samuel Ranti Oke

    2018-04-01

    Full Text Available This research optimized spark plasma sintering (SPS process parameters in terms of sintering temperature, holding time and heating rate for the development of a nano-structured duplex stainless steel (SAF 2205 grade reinforced with titanium nitride (TiN. The mixed powders were sintered using an automated spark plasma sintering machine (model HHPD-25, FCT GmbH, Germany. Characterization was performed using X-ray diffraction and scanning electron microscopy. Density and hardness of the composites were investigated. The XRD result showed the formation of FeN0.068. SEM/EDS revealed the presence of nano ranged particles of TiN segregated at the grain boundaries of the duplex matrix. A decrease in hardness and densification was observed when sintering temperature and heating rate were 1200 °C and 150 °C/min respectively. The optimum properties were obtained in composites sintered at 1150 °C for 15 min and 100 °C/min. The composite grades irrespective of the process parameters exhibited similar shrinkage behavior, which is characterized by three distinctive peaks, which is an indication of good densification phenomena. Keywords: Spark plasma sintering, Duplex stainless steel (SAF 2205, Titanium nitride (TiN, Microstructure, Density, Hardness

  4. Preparation of Ti3Al intermetallic compound by spark plasma sintering

    Science.gov (United States)

    Ito, Tsutomu; Fukui, Takahiro

    2018-04-01

    Sintered compacts of single phase Ti3Al intermetallic compound, which have excellent potential as refractory materials, were prepared by spark plasma sintering (SPS). A raw powder of Ti3Al intermetallic compound with an average powder diameter of 176 ± 56 μm was used in this study; this large powder diameter is disadvantageous for sintering because of the small surface area. The samples were prepared at sintering temperatures (Ts) of 1088, 1203, and 1323 K, sintering stresses (σs) of 16, 32, and 48 MPa, and a sintering time (ts) of 10 min. The calculated relative densities based on the apparent density of Ti3Al provided by the supplier were approximately 100% under all sintering conditions. From the experimental results, it was evident that SPS is an effective technique for dense sintering of Ti3Al intermetallic compounds in a short time interval. In this report, the sintering characteristics of Ti3Al intermetallic compacts are briefly discussed and compared with those of pure titanium compacts.

  5. Preparation and Evaluation of Biodegradable Scleral Plug Containing Curcumin in Rabbit Eye.

    Science.gov (United States)

    Zhang, Jun; Sun, Haiyan; Zhou, Nalei; Zhang, Bin; Ma, Jingxue

    2017-12-01

    To test whether biodegradable curcumin-loaded scleral plug is a promising choice for treating posterior ocular diseases, the study investigated the in vitro release profile of the scleral plug and its safety in vivo. Scleral plugs containing 0.5 mg, 1.0 mg and 1.5 mg curcumin were synthesized by a compression-sintering method. These scleral plugs were placed in tubes containing balanced salt solution (BSS) buffer, which was replaced by fresh buffer daily. The curcumin concentration in the removed aliquot was tested daily for 14 days using high-performance liquid chromatography (HPLC). In the study, 44 rabbits were randomly divided into four groups: control, 0.5 mg, 1.0 mg and 1.5 mg curcumin groups. The scleral plug was trans-scleral fixed in the right eye of the rabbits in the three curcumin-treated groups. The control rabbits only received sclerotomy. The treated rabbit eyes were examined by a slit-lamp biomicroscope, an indirect ophthalmoscope and electroretinogram (ERG), and subjected to histological analysis. The concentration of the 1.5 mg curcumin-loaded scleral plug was higher than 15 μg/ml for consecutive 14 days in vitro. The in vivo experiments revealed intraocular pressure, a-wave and b-wave amplitudes of ERG, and conjunctival reaction degree were not significantly different between the four groups. Retinal structure was normal in the curcumin-treated groups. The sclerotomy wound healed after the plug was completely degraded. Anterior chamber reaction or complications were not observed. The study suggests that curcumin-loaded scleral plug could sustain high concentration of curcumin in vitro and is safe in vivo. It might be a promising alternative choice for the treatment of posterior ocular diseases.

  6. Aspergillus fumigatus colonization of punctal plugs.

    Science.gov (United States)

    Tabbara, Khalid F

    2007-01-01

    Punctal plugs are used in patients with dry eye syndrome to preserve the tears. In this report, I present two cases of Aspergillus fumigatus colonization of punctal plugs. Observational series of two cases. Approval was obtained from the institutional review board. Two men aged 29 and 31 years developed black spots inside the hole of punctal plug, which looked like eyeliner deposits. The deposits inside the hole of the plug in each patient were removed and cultured. Cultures of the two punctal plugs black deposits grew A fumigatus. Bacterial cultures were negative. Colonization of the punctal plug hole with A fumigatus was observed in two cases. It is recommended that punctal plugs be removed in patients undergoing refractive or intraocular procedures or in patients who are receiving topical corticosteroids. Current punctal plugs should be redesigned to avoid the presence of an inserter hole.

  7. Shielding plug for LMFBR type reactors

    International Nuclear Information System (INIS)

    Hashiguchi, Ko.

    1979-01-01

    Purpose: To enable effective removal of liquid metals deposited, if any, in the gaps between a rotary plug and a fixed plug in LMFBR type reactors. Constitution: A plate incorporated with a heater and capable of projecting in a gap between a rotary plug and a fixed plug, and a scraper connected in perpendicular to it are provided to the rotary plug. Solidified liquid metals such as sodium deposited in the gap are effectively removed by the heating with the heater and the scraping action due to the rotation. (Horiuchi, T.)

  8. Influence of sintering atmospheres on the aluminium sintering characteristics

    International Nuclear Information System (INIS)

    Mintzer, S.; Bermudez Belkys, S.

    1993-01-01

    This paper describes the aluminium powder (Al) cool compacted (at 95% from theoretical density) which was sintered at 903 K during 4 hours at different atmospheres; oxidizing (air), inert Argon (Ar), Nitrogen (N) and high vacuum. The results obtained show: a) porosity measurements; greater porosity when sintering in Ar and air. b) Metallographic and Scanning observations: many fine pores (< 1 μm) and pore lines distributed at random, at air sintering and greater pores distributed preferentially near the surface, in Ar and N atmospheres. c) Dimensional changes: tendency to contraction of the samples at N and vacuum sintering and expansion in Ar or air. d) Mechanical properties: greater strength and fluence stresses at air and N sintering. The analysis of the results is performed considering sintering modes in presence of an oxide layer and dropped inert gases. (Author)

  9. Sintering behavior and mechanical properties of a metal injection molded Ti–Nb binary alloy as biomaterial

    International Nuclear Information System (INIS)

    Zhao, Dapeng; Chang, Keke; Ebel, Thomas; Nie, Hemin; Willumeit, Regine; Pyczak, Florian

    2015-01-01

    Highlights: • The sintering of the MIM Ti–Nb alloy consists of three steps. • The Nb particles act as diffusion barriers during sintering. • The TiC x only precipitate in the cooling step during sintering. • The TiC x hardly influence the sintering process of MIM Ti–Nb alloy. • The MIM Ti–Nb alloy exhibits high strength, low Young’s modulus but poor ductility. - Abstract: Sintering behavior, microstructure and mechanical properties of a Ti–16Nb alloy processed by metal injection molding (MIM) technology using elemental powders were investigated in this work by optical microscopy, X-ray diffraction (XRD), dilatometer, scanning electron microscopy (SEM) and energy-dispersive spectroscopy (EDS). It was found that from 700 °C to 1500 °C the homogenization and densification process of MIM Ti–16Nb alloy consisted of three steps, i.e., Ti-diffusion-controlled step, Ti–Nb-diffusion step and matrix-diffusion step. Titanium carbide formation was observed in the samples sintered at 1300 °C and 1500 °C, but not in the ones sintered at 900 °C and 1100 °C. The MIM Ti–16Nb specimens sintered at 1500 °C exhibited a good combination of high tensile strength and low Young’s modulus. However, the titanium carbide particles led to poor ductility

  10. Introduction to powder metallurgy processes for titanium manufacturing

    International Nuclear Information System (INIS)

    Esteban, P. G.; Bolzoni, L.; Ruiz-Navas, E. M.; Gordo, E.

    2011-01-01

    The development of new extraction processes to produce titanium in powder form leads Powder Metallurgy to an advantage position among the manufacturing processes for titanium. The cost reduction of base material, coupled with the economy of the powder metallurgy processes, give titanium industry the chance to diversify its products, which could lead to production volumes able to stabilise the price of the metal. This work reviews some of the Powder Metallurgy techniques for the manufacturing of titanium parts, and describes the two typical approaches for titanium manufacturing: Blending Elemental and Prealloyed Powders. Among others, conventional pressing and sintering are described, which are compared with cold and hot isostatic pressing techniques. Real and potential applications are described. (Author) 71 refs.

  11. Refueling system with small diameter rotatable plugs

    International Nuclear Information System (INIS)

    Ritz, W.C.

    1987-01-01

    This patent describes a liquid-metal fastbreeder nuclear reactor comprising a reactor pressure vessel and closure head therefor, a reactor core barrel disposed within the reactor vessel and enclosing a reactor core having therein a large number of closely spaced fuel assemblies, and the reactor core barrel and the reactor core having an approximately concentric circular cross-sectional configuration with a geometric center in predetermined location within the reactor vessel. The improved refueling system described here comprises: a large controllably rotatable plug means comprising the substantial portion of the closure head, a reactor upper internals structure mounted from the large rotatable plug means. The large rotatable plug means has an approximately circular configuration which approximates the cross-sectional configuration of the reactor core barrel with a center of rotation positioned a first predetermined distance from the geometric center of the reactor core barrel so that the large rotatable plug means rotates eccentrically with respect to the reactor core barrel; a small controllably rotatable plug means affixed to the large rotatable plug means and rotatable with respect thereto. The small rotatable plug means has a center of rotation which is offset a second predetermined distance from the rotational center of the large rotatable plug means so that the small rotatable plug means rotates eccentrically with respect to the large rotatable plug means

  12. The mechanism of hard metal TiC-TiNi composite liquid-phase sintering

    International Nuclear Information System (INIS)

    Akimov, V.V.

    2006-01-01

    The sintering conditions are investigated for hard alloys on their production from powders of titanium nickelide with particle size of 10-25 μ and titanium carbide with particles of 5-10 μ at temperatures of 1280-1350 deg C under pressure of 0.1 MPa with holding at heat for 180-900 s. The analysis of experimental data shows that optimum sintering conditions are determined by the quantity of a binding phase TiNi. In the systems with a binding phase content no more than 40 % a heterogeneous structure with nonuniform aggregates of TiC and TiNi phases is observed. With increasing a binding phase amount up to 50-70 % and a temperature up to 1350 deg C, titanium nickelide melts and spreads uniformly among carbide grains. This results in a low porosity of the composite material and in an increase of thermodynamic stability of the system [ru

  13. Simulation of shear plugging through thin plates using the GRIM Eulerian hydrocode

    Science.gov (United States)

    Church, P.; Cornish, R.; Cullis, I.; Lynch, N.

    2000-03-01

    Ballistic experiments have been performed using aluminum spheres against 10-mm rolled homogenous armour (RHA), MARS270, MARS300, and titanium alloy plates to investigate the influence of the plugging mechanism on material properties. The experiments have measured the threshold for plug mass and velocity as well as the recovered aluminum sphere mass over a range of velocities. Some of the experiments have been simulated using the in-house second generation Eulerian hydrocode GRIM. The calculations feature advanced material algorithms derived from interrupted tensile testing techniques and a triaxial failure model derived from notched tensile tests over a range of strain rates and temperatures. The effect of mesh resolution on the results has been investigated and understood. The simulation results illustrate the importance of the constitutive model in the shear localization process and the subsequent plugging phenomena. The stress triaxiality is seen as the dominant feature in controlling the onset and subsequent propagation of the crack leading to the shear plug. The simulations have demonstrated that accurate numerics coupled with accurate constitutive and fracture algorithms can successfully reproduce the observed experimental features. However, extrapolation of the fracture data leads to the simulations overpredicting the plug damage. The reasons for this are discussed.

  14. Hydrothermal Cold Sintering

    Science.gov (United States)

    Kang, Xiaoyu

    Solid state sintering transforms particle compact to a physically robust and dense polycrystalline monolith driven by reduction of surface energy and curvature. Since bulk diffusion is required for neck formation and pore elimination, sintering temperature about 2/3 of melting point is needed. It thus places limitations for materials synthesis and integration, and contributes to significant energy consumption in ceramic processing. Furthermore, since surface transport requires lower temperature than bulk processes, grain growth is often rapid and can be undesired for physical properties. For these reasons, several techniques have been developed including Liquid Phase Sintering (LPS), Hot Pressing (HP) and Field Assisted Sintering Technique (FAST), which introduce either viscous melt, external pressure or electric field to speed up densification rates at lower temperature. However, because of their inherent reliability on bulk diffusion, temperatures required are often too high for integrating polymers and non-noble metals. Reduction of sintering temperature below 400 °C would require a different densification mechanism that is based on surface transport with external forces to drive volume shrinkage. Densification method combining uniaxial pressure and solution under hydrothermal condition was first demonstrated by Kanahara's group at Kochi University in 1986 and was brought to our attention by the work of Kahari, etc, from University of Oulu on densification of Li2MoO 4 in 2015. This relatively new process showed promising ultra-low densification temperature below 300 °C, however little was known about its fundamental mechanism and scope of applications, which became the main focus of this dissertation. In this work, a uniaxial hydraulic press, a standard stainless steel 1/2 inch diameter die with heating band were utilized in densifying metal oxides. Applied pressure and sintering temperature were between 100 MPa and 700 MPa and from room temperature to 300

  15. Plug Load Behavioral Change Demonstration Project

    Energy Technology Data Exchange (ETDEWEB)

    Metzger, I.; Kandt, A.; VanGeet, O.

    2011-08-01

    This report documents the methods and results of a plug load study of the Environmental Protection Agency's Region 8 Headquarters in Denver, Colorado, conducted by the National Renewable Energy Laboratory. The study quantified the effect of mechanical and behavioral change approaches on plug load energy reduction and identified effective ways to reduce plug load energy. Load reduction approaches included automated energy management systems and behavioral change strategies.

  16. Tube Plugging Criterion for the TPCCW Heat Exchanger of Yonggwang NPP 1 and 2

    International Nuclear Information System (INIS)

    Kim, Hyung Nam; Yoo, Hyun Ju; Choi, Sung Nam; Song, Seok Yoon

    2009-01-01

    The turbine plant component cooling water(TPCCW) system circulates the cooling water to cool the components in the turbine building and discharges the heat from the components through the TPCCW heat exchanger. Recently, Yonggwang NPP 1 and 2 replaced the TPCCW heat exchanger because of tube degradation. The tubing material of new TPCCW heat exchanger of Yonggwang NPP 1 and 2 is titanium. If the tube wall cannot withstand the pressure, the cooling water with the chemicals flows into the tube side and it is discharged to the open water. The chemicals can pollute the open water. Therefore, the tubes of the TPCCW heat exchanger should be inspected and degraded tubes should be plugged. It is inevitable for the materials of the components to be degraded as the power plants become older. The degradation accompanies increasing maintenance cost as well as creating safety issues. The materials and wall thickness of heat exchanger tubes in nuclear power plants are selected to withstand system temperature, pressure, and corrosion. However, tubes have experienced leaks and failures and plugged based upon eddy current testing (ET) results. There are some problems for plugging the heat exchanger tubes since the criterion and its basis are not clearly described. For this reason, the criteria for the tube wall thickness are addressed in order to operate the heat exchangers in nuclear power plant without trouble during the cycle. There are many codes and standards to be referred for calculating the minimum thickness of the heat exchanger tube in the designing stage. However, the codes and standards related to show the tube plugging criteria may not exist currently. In this paper, a method to establish the tube plugging criteria of BOP heat exchangers, which is based on the USNRC Regulatory Guide 1.121, is introduced and the tube plugging criteria for the TPCCW heat exchanger of Yonggwang NPP No. 1 and 2. This method relies on the similar plugging criteria used in the steam generator

  17. Tube Plugging Criterion for the TPCCW Heat Exchanger of Yonggwang NPP 1 and 2

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Hyung Nam; Yoo, Hyun Ju; Choi, Sung Nam; Song, Seok Yoon [Korea Electric Power Research Institute, Daejeon (Korea, Republic of)

    2009-05-15

    The turbine plant component cooling water(TPCCW) system circulates the cooling water to cool the components in the turbine building and discharges the heat from the components through the TPCCW heat exchanger. Recently, Yonggwang NPP 1 and 2 replaced the TPCCW heat exchanger because of tube degradation. The tubing material of new TPCCW heat exchanger of Yonggwang NPP 1 and 2 is titanium. If the tube wall cannot withstand the pressure, the cooling water with the chemicals flows into the tube side and it is discharged to the open water. The chemicals can pollute the open water. Therefore, the tubes of the TPCCW heat exchanger should be inspected and degraded tubes should be plugged. It is inevitable for the materials of the components to be degraded as the power plants become older. The degradation accompanies increasing maintenance cost as well as creating safety issues. The materials and wall thickness of heat exchanger tubes in nuclear power plants are selected to withstand system temperature, pressure, and corrosion. However, tubes have experienced leaks and failures and plugged based upon eddy current testing (ET) results. There are some problems for plugging the heat exchanger tubes since the criterion and its basis are not clearly described. For this reason, the criteria for the tube wall thickness are addressed in order to operate the heat exchangers in nuclear power plant without trouble during the cycle. There are many codes and standards to be referred for calculating the minimum thickness of the heat exchanger tube in the designing stage. However, the codes and standards related to show the tube plugging criteria may not exist currently. In this paper, a method to establish the tube plugging criteria of BOP heat exchangers, which is based on the USNRC Regulatory Guide 1.121, is introduced and the tube plugging criteria for the TPCCW heat exchanger of Yonggwang NPP No. 1 and 2. This method relies on the similar plugging criteria used in the steam generator

  18. Titanium di-oxide films using a less hygroscopic colloidal precursor

    Energy Technology Data Exchange (ETDEWEB)

    Vandana,, E-mail: vandana1@nplindia.org; Batra, Neha; Kumar, Praveen; Sharma, Pooja; Singh, P.K., E-mail: pksingh@nplindia.org

    2014-04-01

    We report the study of titanium dioxide films (TiO{sub 2}) using titanium di-isopropoxyl di-2ethyl hexanoate Ti(OC{sub 3}H{sub 7}){sub 2} (C{sub 7}H{sub 15}COO){sub 2} colloidal precursor. This compound is less hygroscopic in nature and easy to use with processes like spin or dip coating. Thin films of TiO{sub 2} are made on silicon substrates and their structural and optical properties are studied. The effect of Ti content in the precursor, sintering temperature and its duration on film thickness and refractive index are investigated. Refractive index shows an increasing trend with the rise in the sintering temperature but remains unchanged with the time. The film thickness decreases with both sintering temperature and time and increases with Ti content in the precursor. Reflectivity measurements show marked reduction in the reflection losses compared to bare silicon surface wherein the film thickness is altered by spin speed. XRD results show anatase phase in the samples sintered at lower temperature (<680 °C), however, a mix of anatase, brookite and rutile phases is seen above this temperature. In the samples sintered above 1100 °C, rutile phase is dominant. These results are supported by the X-ray photoelectron spectroscopy. Atomic force microscopy reveals larger grain size at higher sintering temperature. The titanium dioxide films of desirable thickness and refractive index could be used as an antireflection coating on solar cells. - Highlights: • TiO{sub 2} films are made using titanium di-isopropoxyl di-2ethyl hexanoate precursor. • Effect of Ti content in the precursor, sintering temperature and time is studied. • Refractive index (μ) increases with sintering temperature but is independent of time. • Films of desired thickness and μ could be used as an antireflection coating. • XRD results show that rutile phase dominates in samples sintered above 1100 °C.

  19. Nuclear fuel rod end plug weld inspection

    International Nuclear Information System (INIS)

    Parker, M. A.; Patrick, S. S.; Rice, G. F.

    1985-01-01

    Apparatus and method for testing TIG (tungsten inert gas) welds of end plugs on a sealed nuclear reactor fuel rod. An X-ray fluorescent spectrograph testing unit detects tungsten inclusion weld defects in the top end plug's seal weld. Separate ultrasonic weld inspection system testing units test the top end plug's seal and girth welds and test the bottom end plug's girth weld for penetration, porosity and wall thinning defects. The nuclear fuel rod is automatically moved into and out from each testing unit and is automatically transported between the testing units by rod handling devices. A controller supervises the operation of the testing units and the rod handling devices

  20. Multimeediaetendus : Opera Gets Plugged / Eve Arpo

    Index Scriptorium Estoniae

    Arpo, Eve

    2008-01-01

    Eesti Muusika- ja Teatriakadeemia lühiooperite õhtul "Opera Gets Plugged" etendunud lavastustest - Monika Mattieseni "DMeeter" ja Age Hirve "Tuleloitsija": Mõlema lavastaja ja projektijuht Liis Kolle

  1. Friction Pull Plug and Material Configuration for Anti-Chatter Friction Pull Plug Weld

    Science.gov (United States)

    Littell, Justin Anderson (Inventor)

    2016-01-01

    A friction pull plug is provided for use in forming a plug weld in a hole in a material. The friction pull plug includes a shank and a series of three frustoconical sections. The relative sizes of the sections assure that a central one of the sections defines the initial contact point between the hole's sides. The angle defined by the central one of the sections reduces or eliminates chatter as the plug is pulled into the hole.

  2. Physical and chemical characterization of titanium-alginate samples for biomedical applications

    Energy Technology Data Exchange (ETDEWEB)

    Morani, L.M.; Ribeiro, A.A.; Oliveira, M.V. de; Dantas, F.M.L., E-mail: marize.varella@int.gov.b [Instituto Nacional de Tecnologia (INT), Rio de Janeiro, RJ (Brazil); Leao, M.H.M.R. [Universidade Federal do Rio de Janeiro (EQ/UFRJ), RJ (Brazil). Escola de Quimica

    2010-07-01

    The sol-gel technique combined with powder metallurgy may be an alternative to produce titanium parts for bioengineering, with the advantage of eliminating the powder compaction step, which may introduce defects. The present work introduces a system consisted of titanium powder and sodium alginate suspension, which undergoes reticulation in contact with a calcium salt solution, obtaining titanium/calcium alginate hydrogel with granule morphology. The characterization of the raw materials and granules of calcium alginate and titanium/calcium alginate was performed by x-ray fluorescence spectroscopy and thermogravimetric analysis. The granules topography was analyzed by scanning electron microscopy/EDS. Titanium and sodium alginate chemical composition were adequate for use as raw materials, showing that the methodology used is suitable for processing titanium samples for further consolidation by sintering, in order to produce titanium parts. (author)

  3. Mechanisms of sintering

    International Nuclear Information System (INIS)

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

    1980-01-01

    The basic mechanisms by which the material moves during sintering have not only held a strange fascination but are also very important in determining the properties of the end product. Kuczynski's exponent method has been subsequently refined by several schools to make it increasingly reliable. There is now a fairly good understanding of mechanisms in some of the materials. However in others the issue is complicated by their basic nature. The problems of ambiguity in criterion and that of more than one mechanism being simultaneously operative have been tackled with dexterity by Ashby for drawing sintering mechanism diagrams. The method has been modified to give Relative Contribution Diagrams (RCD). These yield additional information and have been used for analysis. The main criticism against this is that it uses a very large number of rate equations and material properties, which can communicate their inaccuracies to the diagram. A case study of UO 2 was undertaken and it has been shown quantitatively that inaccuracies in a smaller number of properties only affect the diagrams to any significant extent. (auth.)

  4. Lubricant influence on the ejection and roughness of in-die electro sinter forged Ti-discs

    DEFF Research Database (Denmark)

    Cannella, Emanuele; Nielsen, Chris Valentin

    2018-01-01

    Electro Sinter Forging (ESF) is a new sintering process based on Joule heating by high electrical current flowing through compacted metal powder under mechanical pressure. The whole process takes about three seconds and is based on a closed-die setup, where the sample is sintered inside a die....... A near-net shape component is therefore manufactured. One of the challenges associated with this process is the ejection of the sample after sintering. Due to powder compaction and axial loading during sintering, a radial pressure is generated at the die/sample interface. Consequently, the ejection can...... of commercially pure titanium powder. The force was measured while ejecting the samples by using a speed-controlled press. The surface roughness parameter Sa was measured by using a laser confocal microscope....

  5. 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)

  6. Principle plug design for deposition tunnels

    International Nuclear Information System (INIS)

    Haaramo, M.; Lehtonen, A.

    2009-06-01

    This report examines the plug structures to be built in the deposition tunnels of the repository. The deposition tunnels located below the depth of 400 metres have been used as input data. Each plug consists of a massive concrete structure. The planned maximum pressure acting on the plug is 7.5 MPa. It consists of 4.5 MPa of groundwater pressure and 3 MPa of swelling pressure of the backfill. Five different plug types have been examined. Two of them (butt and irregular plug) turned out to be difficult from the point of view of other works in the central and deposition tunnels. One type (straight plug) requires a lot of construction material. Wedge-shaped and dome plugs have been examined more carefully. The wedge shaped plug has advantageous properties in comparison with the dome plug, such as a three dimensional state of stress, the wedging effect which increases strength as pressure increases and larger tolerances for the excavation of the slot. Leakage water has a longer path through the wedge shaped plug than through the dome plug. Pressure load affects the wedge shaped plug, creating normal stresses, which are compressive along each coordinate axis. The long-term rise in temperature in the deposition tunnels can produce high extra stresses in all the plug alternatives. These stresses make it necessary to increase the strength of the concrete or the distance between the plug and the nearest deposition hole. The stability effects of different plug distances and deposition tunnel orientations have been examined. The plug does not significantly affect stresses in the surrounding bedrock or the stability of the bedrock. Stresses caused by excavation and temperature rise are decisive factors. A groundwater chloride content of 0-3% in the environment of the repository is used as input data. It affects the tightness of the concrete and the quality of the cement. Cement has to be sulphate resistant with a low pH value. Low pH results in the weakening of the corrosion

  7. Mastering Eclipse plug-in development

    CERN Document Server

    Blewitt, Alex

    2014-01-01

    If you are a Java developer who is familiar with the Eclipse plug-in environment, this book covers the advanced concepts that you need to know to achieve true expertise. Prior experience in creating Eclipse plug-ins is assumed for this book.

  8. Plugging regime in the pump limiter throat

    International Nuclear Information System (INIS)

    Ghendrih, P.; Grosman, A.; Samain, A.; Capes, H.; Morera, J.P.

    1988-08-01

    The plugging regime -with no outstreaming neutral flux- is studied for a closed configuration pump limiter (throat). We derive the plugging length and the neutral density build-up at the neutralizer plate. The analytical expressions are supported by numerical evidence. We find an improved efficiency related to the throat effect mainly due to neutral-sidewall interactions

  9. Plug-In Tutor Agents: Still Pluggin'

    Science.gov (United States)

    Ritter, Steven

    2016-01-01

    "An Architecture for Plug-in Tutor Agents" (Ritter and Koedinger 1996) proposed a software architecture designed around the idea that tutors could be built as plug-ins for existing software applications. Looking back on the paper now, we can see that certain assumptions about the future of software architecture did not come to be, making…

  10. Multiservice utility plug for remote fuel reprocessing

    International Nuclear Information System (INIS)

    Goldmann, L.H. Jr.; Jensen, D.A.

    1979-10-01

    This paper presents the design of a multiservice utility plug and drive system to be used for reliably engaging and disengaging all utility connections automatically that serve large portable equipment modules. The modules are arranged into a fuel processing production line within the Fuels and Materials Examination Laboratory. The utility plugs allow the modules to be easily replaced, rearranged or removed for maintenance

  11. Explosive plugging of nuclear heat exchangers

    International Nuclear Information System (INIS)

    Crossland, B.; Bahrani, A.S.; Townsley, W.J.

    1977-01-01

    Explosive welding is a well established process for cladding one metal on another or for welding tubes to tubeplates or lap welding, etc. Recently, the process has been adapted to plugging of heat exchangers in conventional and nuclear power plant, where it has already been accepted especially in situations where the access is difficult and remote from the site of plugging. The paper describes the explosive plugging techniques developed in the Department of Mechanical and Industrial Engineering of The Queen's University of Belfast for the reheater and superheater of the PFR, and for the reheater of the AGR. For the PFR a point charge system has been used which causes a spherical expansion of the plug, which gives two zones of welding. Initially for the much larger plug required for the AGR it was proposed to use a parallel stand-off welding set-up, but it proved difficult or impossible to avoid a crevice. Consequently, a rim charge set-up has been developed which gives a circular ring expansion of the plug with two zones of welding. Besides the problem of the design of the plug and explosive charge geometry it has also been necessary to consider the distortion of holes adjoining the hole in which a plug is welded. Bunging of adjoining holes in order to reduce the distortion has also been investigated

  12. Development of titanium based biocomposite by powder metallurgy processing with in situ forming of Ca-P phases

    Energy Technology Data Exchange (ETDEWEB)

    Karanjai, Malobika [International Advanced Research Centre for Powder Metallurgy and New Materials, Balapur P.O., Hyderabad 500005, Andhra Pradesh (India)]. E-mail: malobika@arci.res.in; Sundaresan, Ranganathan [International Advanced Research Centre for Powder Metallurgy and New Materials, Balapur P.O., Hyderabad 500005, Andhra Pradesh (India); Rao, Gummididala Venkata Narasimha [International Advanced Research Centre for Powder Metallurgy and New Materials, Balapur P.O., Hyderabad 500005, Andhra Pradesh (India); Mohan, Tallapragada Raja Rama [Metallurgical Engineering and Materials Science Department, Indian Institute of Technology, Powai, Mumbai 400076, Maharashtra (India); Kashyap, Bhagwati Prasad [Metallurgical Engineering and Materials Science Department, Indian Institute of Technology, Powai, Mumbai 400076, Maharashtra (India)

    2007-02-25

    Composites of titanium and calcium-phosphorus phases were developed by powder metallurgy processing and evaluated for bioactivity. Titanium hydride powder and precursors of calcium and phosphorus in the form of calcium carbonate and di-ammonium hydrogen orthophosphate were mixed in different proportions, compacted and calcined in different atmospheres. The calcined compacts were subsequently crushed, recompacted and sintered in vacuum. In situ formation of bioactive phases like hydroxylapatite, tricalcium phosphate and calcium titanate during the calcination and sintering steps was studied using X-ray diffraction. The effect of calcination atmosphere on density, interconnected porosity, phase composition and modulus of rupture of sintered composites was examined. The sintered composites were immersed in simulated body fluid for 7 days to observe their in vitro behaviour with XRD and FTIR spectroscopic identification of deposits. Composites with 10 wt% precursors sintered from vacuum calcined powder gave the best results in terms of bioactive phases, density and strength.

  13. Mixture for plugging absorption zones

    Energy Technology Data Exchange (ETDEWEB)

    Sitinkov, G V; Kovalenko, N G; Makarov, L V; Zinnatulchin, Ts Kh

    1981-01-17

    A mixture is proposed for plugging absorption zones. The mixture contains synthetic polymer and a solvent. So as to increase the penetrability of the mixture through a reduction in its viscosity and an increase in insulation properties, the compound contains either Capron or Neilon as the synthetic polyamide resin polmyer, and concentrated chloride as the solvent. The mixture is prepared in a special AzINMASh-30 unit (acid cart). After the mixture has been produced, it is injected into the borehole by means of an acid cart pump. So as to prevent coaggulation at the point when the mixture in injected into the stratum through tubes, the mixture is placed betwen chemically inert fluids, for example, a clay mortar. The inert and compressed fluids are injected by means of a cementing unit. The entire process of production and application of the mixture is simple and fully automated through the use of well-known equipment.

  14. Plug-in Hybrid Initiative

    Energy Technology Data Exchange (ETDEWEB)

    Goodman, Angie; Moore, Ray; Rowden, Tim

    2013-09-27

    Our main project objective was to implement Plug-in Electric Vehicles (PEV) and charging infrastructure into our electric distribution service territory and help reduce barriers in the process. Our research demonstrated the desire for some to be early adopters of electric vehicles and the effects lack of education plays on others. The response of early adopters was tremendous: with the initial launch of our program we had nearly 60 residential customers interested in taking part in our program. However, our program only allowed for 15 residential participants. Our program provided assistance towards purchasing a PEV and installation of Electric Vehicle Supply Equipment (EVSE). The residential participants have all come to love their PEVs and are more than enthusiastic about promoting the many benefits of driving electric.

  15. 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

  16. Effect of intense vibration treatment on the powder fine structure and reaction ability during sintering

    International Nuclear Information System (INIS)

    Pribytkov, G.A.; Chzhan Khajfen; Yuj Baokhaj; Khu Zoangchi

    2003-01-01

    Effects of a vibration grinding treatment of TiC-Ni and TiC-Ni-Cr titanium carbide-metal powder composition on the size of X-ray coherent scattering zones as well as the melt and crystallization temperatures under liquid-phase sintering have been investigated. Hardness and strength of composites sintered from the blends grinded for 4 h and more are found to be decreased that is explained by high porosity due to oxygen contamination of powder blends during a dry grinding treatment [ru

  17. Sinterability and microstructure evolution during sintering of ferrous powder mixtures

    Directory of Open Access Journals (Sweden)

    Kétner Bendo Demétrio

    2013-01-01

    Full Text Available The present work is focused on ferrous powder metallurgy and presents some results of a development of a suitable masteralloy for use as an additive to iron powder for the production of sintered steels. The masteralloy was produced by melting a powder mixture containing approximately Fe + 20% Ni + 20% Mn + 20% Si + 1% C (wt%, in order to obtain a cast billet that was converted into fine powder by crushing and milling. It was observed presence of SiC in the masteralloy after melting that is undesirable in the alloy. Si element should be introduced by using ferrosilicon. Sintered alloys with distinct contents of alloying elements were prepared by mixing the masteralloy powder to plain iron powder. Samples were produced by die compaction of the powder mixtures and sintering at 1200 °C in a differential dilatometer in order to record their linear dimensional behaviour during heating up and isothermal sintering, aiming at studying the sinterability of the compacts. Microstructure development during sintering was studied by SEM, XRD and microprobe analyses.

  18. Friction Pull Plug Welding in Aluminum Alloys

    Science.gov (United States)

    Brooke, Shane A.; Bradford, Vann

    2012-01-01

    NASA's Marshall Space Flight Center (MSFC) has recently invested much time and effort into the process development of Friction Pull Plug Welding (FPPW). FPPW, is a welding process similar to Friction Push Plug Welding in that, there is a small rotating part (plug) being spun and simultaneously pulled (forged) into a larger part. These two processes differ, in that push plug welding requires an internal reaction support, while pull plug welding reacts to the load externally. FPPW was originally conceived as a post proof repair technique for the Space Shuttle fs External Tank. FPPW was easily selected as the primary weld process used to close out the termination hole on the Constellation Program's ARES I Upper Stage circumferential Self-Reacting Friction Stir Welds (SR-FSW). The versatility of FPPW allows it to also be used as a repair technique for both SR-FSW and Conventional Friction Stir Welds. To date, all MSFC led development has been concentrated on aluminum alloys (2195, 2219, and 2014). Much work has been done to fully understand and characterize the process's limitations. A heavy emphasis has been spent on plug design, to match the various weldland thicknesses and alloy combinations. This presentation will summarize these development efforts including weld parameter development, process control, parameter sensitivity studies, plug repair techniques, material properties including tensile, fracture and failure analysis.

  19. Plug cementing: Horizontal to vertical conditions

    Energy Technology Data Exchange (ETDEWEB)

    Calvert, D.G.; Heathman, J.F.; Griffith, J.E.

    1995-12-31

    This paper presents an in-depth study of cement plug placement that was conducted with large-scale models for the improvement of plug cementing practices and plug integrity. Common hole and workstring geometries were examined with various rheology and density ratios between the drilling fluid and cement. The critical conditions dictating the difference between success and failure for various wellbore angles and conditions were explored, and the mechanisms controlling slurry movement before and after placement are now better understood. An understanding of these mechanisms allows the engineer to better tailor a design to specific hole conditions. Controversial concepts regarding plug-setting practices have been examined and resolved. The cumulative effects of density, rheology, and hole angle are major factors affecting plug success. While the Boycott effect and an extrusion effect were observed to be predominant in inclined wellbores, a spiraling or {open_quotes}roping{close_quotes} effect controls slurry movement in vertical wellbores. Ultimate success of a cement plug can be obtained if allowances are made for these effects in the job design, provided all other previously published recommended placement practices are followed. Results of this work can be applied to many sidetracking and plug-to-abandon operations. Additionally, the understanding of the fluid movement (creep) mechanisms holds potential for use in primary and remedial cementing work, and in controlling the placement of noncementitious fluids in the wellbore.

  20. 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.

  1. EBR-II rotating plug seal maintenance

    International Nuclear Information System (INIS)

    Allen, K.J.

    1986-01-01

    The EBR-II rotating plug seals require frequent cleaning and maintenance to keep the plugs from sticking during fuel handling. Time consuming cleaning on the cover gas and air sides of the dip ring seal is required to remove oxidation and sodium reaction products that accumulate and stop plug rotation. Despite severely limited access, effective seal cleaning techniques have removed 11 800 lb (5 352 kg) of deposits from the seals since 1964. Temperature control modifications and repairs have also required major maintenance work. Suggested seal design recommendations could significantly reduce maintenance on future similar seals

  2. Solvent-free biodegradable scleral plugs providing sustained release of vancomycin, amikacin, and dexamethasone--an in vivo study.

    Science.gov (United States)

    Peng, Yi-Jie; Kau, Yi-Chuan; Wen, Chin-Wei; Liu, Kuo-Sheng; Liu, Shih-Jung

    2010-08-01

    Delivering effective drugs at sufficiently high concentrations to the area of infection is a standard treatment for infectious disease, such as endophthalmitis. This is currently done by empirical trans pars plana intravitreal injection of both antibiotics directed against gram-positive and gram-negative microorganisms and steroids. However, injections by needles repeatedly may increase the risks of intraocular infection and hemorrhage, as well as retinal detachment. This article explores the alternative of using biodegradable polymers as scleral plugs for a long-term drug release in vivo. To manufacture plugs, poly(lactide-glycolide) copolymers were first mixed with vancomycin, amikacin, and dexamethasone. The mixture was compressed and sintered at 55 degrees C to form scleral plugs 1.4 mm in diameter. Biodegradable scleral plugs released high concentrations of antibiotics (well above the minimum inhibitory concentrations, MIC) and steroids in vivo for the period of time needed to treat intraocular infection. In addition, no major complications such as infectious or sterile endophthalmitis, retinal detachment, ocular phthisis, or uvea protrusion at sclerotomy site were observed throughout the experiment. The sclerotomy wound healed after total degradation of the scleral implants without leakage or local necrosis. Antibiotic/steroid-impregnated biodegradable scleral plugs may have a potential role in the treatment of various intraocular infections. (c) 2010 Wiley Periodicals, Inc.

  3. Dependence of fracture toughness of molybdenum laser welds on dendritic spacing and in situ titanium additions

    International Nuclear Information System (INIS)

    Jellison, J.L.

    1979-01-01

    The fracture toughness of molybdenum welds has been improved by in situ gettering of oxygen by means of physically deposited titanium. The addition of titanium suppressed brittle intergranular fracture. Pulsed laser welds (both Nd:YAG and CO 2 ) exhibited superior toughness to that of continuous wave CO 2 laser welds. Also, welds of vacuum arc remelted grades were tougher than those of sintered molybdenum. However, weld toughness could not be correlated with either oxygen or carbon content

  4. The preparation of titanium-vanadium carbide/nickel cermets. Technical report

    International Nuclear Information System (INIS)

    Precht, W.; Sprissler, B.

    1976-01-01

    Titanium/vanadium alloy carbide rods were prepared by a zone melting procedure. Wetting studies were carried out using sections of the fused rods and candidate matrix material. It was established that nickel exhibits excellent wetting of (Ti, V) C, and accordingly cermet blends were prepared and liquid phase sintered. Processing parameters are discussed as well as their effect on the final microstructure. Alternate methods for cermet preparation are offered which use as received titanium carbide and vanadium carbide powders

  5. Titanium nitride deposition in titanium implant alloys produced by powder metallurgy

    International Nuclear Information System (INIS)

    Henriques, V.A.R.; Cairo, C.A.A.; Faria, J.; Lemos, T.G.; Galvani, E.T.

    2009-01-01

    Titanium nitride (TiN) is an extremely hard material, often used as a coating on titanium alloy, steel, carbide, and aluminum components to improve wear resistance. Electron Beam Physical Vapor Deposition (EB-PVD) is a form of deposition in which a target anode is bombarded with an electron beam given off by a charged tungsten filament under high vacuum, producing a thin film in a substrate. In this work are presented results of TiN deposition in targets and substrates of Ti (C.P.) and Ti- 13 Nb- 13 Zr obtained by powder metallurgy. Samples were produced by mixing of hydride metallic powders followed by uniaxial and cold isostatic pressing with subsequent densification by sintering between 900°C up to 1400 °C, in vacuum. The deposition was carried out under nitrogen atmosphere. Sintered samples were characterized for phase composition, microstructure and microhardness by X-ray diffraction, scanning electron microscopy and Vickers indentation, respectively. It was shown that the samples were sintered to high densities and presented homogeneous microstructure, with ideal characteristics for an adequate deposition and adherence. The film layer presented a continuous structure with 15μm. (author)

  6. Process for making a titanium diboride-chromium diboride-yttrium titanium oxide ceramic composition

    Science.gov (United States)

    Holcombe, C.E.; Dykes, N.L.

    1992-04-28

    A ceramic composition is described. The ceramic composition consists essentially of from about 84 to 96 w/o titanium diboride, from about 1 to 9 w/o chromium diboride, and from about 3 to about 15 w/o yttrium-titanium-oxide. A method of making the ceramic composition is also described. The method of making the ceramic composition comprises the following steps: Step 1--A consolidated body containing stoichiometric quantities of titanium diboride and chromium diboride is provided. Step 2--The consolidated body is enclosed in and in contact with a thermally insulated package of yttria granules having a thickness of at least 0.5 inches. Step 3--The consolidated body enclosed in the thermally insulated package of yttria granules is heated in a microwave oven with microwave energy to a temperature equal to or greater than 1,900 degrees centigrade to sinter and uniformly disperse yttria particles having a size range from about 1 to about 12 microns throughout the consolidated body forming a densified body consisting essentially of titanium diboride, chromium diboride, and yttrium-titanium-oxide. The resulting densified body has enhanced fracture toughness and hardness. No Drawings

  7. Storage shaft definitive closure plug and method

    International Nuclear Information System (INIS)

    Dardaine, M.

    1992-01-01

    A definitive closure plug system for radioactive waste storage at any deepness, is presented. The inherent weight of the closure materials is used to set in the plug: these materials display an inclined sliding surface in such a way that when the closure material rests on a stable surface of the shaft storage materials, the relative sliding of the different materials tends to spread them towards the shaft internal wall so as to completely occlude the shaft

  8. PLUGGING AND UNPLUGGING OF WASTE TRANSFER PIPELINES

    International Nuclear Information System (INIS)

    Ebadian, M.A.

    1999-01-01

    This project, which began in FY97, involves both the flow loop research on plugging and unplugging of waste transfer pipelines, and the large-scale industrial equipment test of plugging locating and unplugging technologies. In FY98, the related work was performed under the project name ''Mixing, Settling, and Pipe Unplugging of Waste Transfer Lines.'' The mixing, settling, and pipeline plugging and unplugging are critical to the design and maintenance of a waste transfer pipeline system, especially for the High-Level Waste (HLW) pipeline transfer. The major objective of this work is to recreate pipeline plugging conditions for equipment testing of plug locating and removal and to provide systematic operating data for modification of equipment design and enhancement of performance of waste transfer lines used at DOE sites. As the waste tank clean-out and decommissioning program becomes active at the DOE sites, there is an increasing potential that the waste slurry transfer lines will become plugged and unable to transport waste slurry from one tank to another or from the mixing tank to processing facilities. Transfer systems may potentially become plugged if the solids concentration of the material being transferred increases beyond the capability of the prime mover or if upstream mixing is inadequately performed. Plugging can occur due to the solids' settling in either the mixing tank, the pumping system, or the transfer lines. In order to enhance and optimize the slurry's removal and transfer, refined and reliable data on the mixing, sampling, and pipe unplugging systems must be obtained based on both laboratory-scale and simulated in-situ operating conditions

  9. Improved Processing of Titanium Alloys by Metal Injection Moulding

    International Nuclear Information System (INIS)

    Sidambe, A T; Figueroa, I A; Todd, I; Hamilton, H

    2011-01-01

    The commercially pure (CP-Ti) and Ti6Al4V (Ti-64) powders with powder size of sub 45-micron were mixed with a water soluble binder consisting of a major fraction of Polyethylene Glycol (PEG), a minor fraction of Polymethylmethacrylate (PMMA) and some stearic acid as surfactant. The pelletised mix was injection-moulded into standard tensile bar specimens and then subjected solvent debinding by water leaching and thermal debinding in an argon atmosphere. The titanium compacts were then subjected to sintering studies using the Taguchi method. The results of the oxygen impurity levels of the sintered parts are presented in this paper. Titanium parts conforming to Grade 2 requirements were achieved for CP-Ti whilst those conforming to Grade 5 were achieved for Ti-64.

  10. Plug-In Hybrid Electric Vehicle Basics | NREL

    Science.gov (United States)

    Plug-In Hybrid Electric Vehicle Basics Plug-In Hybrid Electric Vehicle Basics Imagine being able to one that's in a standard hybrid electric vehicle. The larger battery pack allows plug-in hybrids to between fill-ups) that's very similar to the range of a conventional vehicle. A plug-in hybrid vehicle's

  11. Electrochemical surface modification of titanium in dentistry.

    Science.gov (United States)

    Kim, Kyo-Han; Ramaswamy, Narayanan

    2009-01-01

    Titanium and its alloys have good biocompatibility with body cells and tissues and are widely used for implant applications. However, clinical procedures place more stringent and tough requirements on the titanium surface necessitating artificial surface treatments. Among the many methods of titanium surface modification, electrochemical techniques are simple and cheap. Anodic oxidation is the anodic electrochemical technique while electrophoretic and cathodic depositions are the cathodic electrochemical techniques. By anodic oxidation it is possible to obtain desired roughness, porosity and chemical composition of the oxide. Anodic oxidation at high voltages can improve the crystallinity of the oxide. The chief advantage of this technique is doping of the coating of the bath constituents and incorporation of these elements improves the properties of the oxide. Electrophoretic deposition uses hydroxyapatite (HA) powders dispersed in a suitable solvent at a particular pH. Under these operating conditions these particles acquire positive charge and coatings are obtained on the cathodic titanium by applying an external electric field. These coatings require a post-sintering treatment to improve the coating properties. Cathodic deposition is another type of electrochemical method where HA is formed in situ from an electrolyte containing calcium and phosphate ions. It is also possible to alter structure and/or chemistry of the obtained deposit. Nano-grained HA has higher surface energy and greater biological activity and therefore emphasis is being laid to produce these coatings by cathodic deposition.

  12. Test plan: Potash Core Test. WIPP experimental program borehole plugging

    International Nuclear Information System (INIS)

    Christensen, C.L.

    1979-09-01

    The Potash Core Test will utilize a WIPP emplaced plug to obtain samples of an in-situ cured plug of known mix constituents for bench scale testing. An earlier effort involved recovery at the salt horizon of Plug 217, a 17 year old plug in a potash exploration hole for bond testing, but the lack of particulars in the emplacement precluded significant determination of plug performance

  13. Liquid phase sintering of carbides using a nickel-molybdenum alloy

    International Nuclear Information System (INIS)

    Barranco, J.M.; Warenchak, R.A.

    1987-01-01

    Liquid phase vacuum sintering was used to densify four carbide groups. These were titanium carbide, tungsten carbide, vanadium carbide, and zirconium carbide. The liquid phase consisted of nickel with additions of molybdenum of from 6.25 to 50.0 weight percent at doubling increments. The liquid phase or binder comprised 10, 20, and 40 percent by weight of the pressed powders. The specimens were tested using 3 point bending. Tungsten carbide showed the greatest improvement in bend rupture strength, flexural modulus, fracture energy and hardness using 20 percent binder with lesser amounts of molybdenum (6.25 or 12.5 wt %) added to nickel compared to pure nickel. A refinement in the carbide microstructure and/or a reduction in porosity was seen for both the titanium and tungsten carbides when the alloy binder was used compared to using the nickel alone. Curves depicting the above properties are shown for increasing amounts of molybdenum in nickel for each carbide examined. Loss of binder phase due to evaporation was experienced during heating in vacuum at sintering temperatures. In an effort to reduce porosity, identical specimens were HIP processed at 15 ksi and temperatures averaging 110 C below the sintering g temperature. The tungsten carbide and titanium carbide series containing 80 and 90 weight percent carbide phase respectively showed improvement properties after HIP while properties decreased for most other compositions

  14. Microstructural development and mechanical properties of iron based cermets processed by pressureless and spark plasma sintering

    International Nuclear Information System (INIS)

    Alvaredo, P.; Gordo, E.; Van der Biest, O.; Vanmeensel, K.

    2012-01-01

    Highlights: ► Processing of Fe-based cermets by pressureless sintering and spark plasma sintering. ► Influence of carbon content on the sintering mechanism and hardness. ► The cermet phase diagram was calculated and permits to explain the microstructure. ► SPS provides ferritic matrix and different carbide distribution than CPS samples. ► Pressureless sintered samples contain retained austenite at room temperature. - Abstract: Iron-based cermets are an interesting class of metal-ceramic composites in which properties and the factors influencing them are to be explored. In this work the metal matrix contains Cr, W, Mo and V as alloying elements, and the hard phase is constituted by 50 vol% of titanium carbonitride (TiCN) particles. The work studies the influence of the C content and the processing method on the sinterability, microstructure and hardness of the developed cermet materials. For that purpose, cermet samples with different C content in the matrix (0 wt%, 0.25 wt%, 0.5 wt%, 1.0 wt%) were prepared by conventional pressureless sintering (CPS) and, in order to achieve finer microstructures and to reduce the sintering time, by spark plasma sintering (SPS). The density and hardness (HV30) of the processed materials was evaluated, while their phase composition and microstructure was characterised by X-ray diffraction (XRD) and scanning electron microscopy (SEM), respectively. The equilibrium phase diagram of the composite material was calculated by ThermoCalc software in order to elucidate the influence of the carbon content on the obtained phases and developed microstructures.

  15. 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.)

  16. Interaction of titanium beryllide with steam at high temperatures

    International Nuclear Information System (INIS)

    Munakata, Kenzo; Wada, Kohei; Akimoto, Yusuke; Takeda, Haruki; Nakamura, Ayano; Kim, Jae-Hwan; Nakamichi, Masaru

    2014-01-01

    Highlights: • Some central and peripheral parts of a plasma sintered titanium beryllide disk were exposed to water vapor at 1273 K. • H 2 gas generation rate of the central part was found to be lower than that of the peripheral part. • Central parts of a plasma sintered titanium beryllide disk were exposed to water vapor at 1273 K with different temperature controls. • H 2 gas generation was found to be affected by thermal treatment. - Abstract: Some central and peripheral parts of a plasma sintered titanium beryllide disk were exposed to water vapor at temperatures raised up to 1273 K. Hydrogen generation and oxidation properties of the titanium beryllide were investigated. The amount of H 2 generation of the central part was found to be smaller than that of the peripheral part, and this can be attributed to difference in the larger fractions of the Be phase on their surface. Thus, different temperature programed experiments were performed using samples cut out from the central part. In an experiment, the temperature of the sample was raised stepwise and behavior of hydrogen generation was investigated. It was found that hydrogen generation does not take place at the temperatures below 1273 K and the amount of hydrogen generated is far smaller. Another experiment was carried out after a sample had been annealed under a dry Ar gas at 1273 K. In this case, the amount of hydrogen generated from the surface decreased. These results indicate the thermal treatment of the titanium beryllide samples affects their reactivity with water vapor

  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. Kinetics of sintering of uranium dioxide

    International Nuclear Information System (INIS)

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

    1978-01-01

    The kinetics of sintering of UO 2 powders derived from ADU route and calcined at different temperatures was studied. The activation energy for sintering was found to depend on the calcination temperature, the density chosen and the sintering temperature range. The motive force for sintering is the excess free energy in the particle system. This exists in the powder compact in the form of surface energy and the excess lattice energy due to defects. The defects which can be eliminated at the operating temperature are responsible for the mobility and hence sintering. This concept of the motive force for sintering has been used to explain the difference in the activation energies observed in the present study. This would also explain phenomena such as attainment of limiting density, presence of optimum sintering temperature and the influence of calcination treatments on the sintering behaviour of powders. (author)

  19. 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.

  20. Titanium and titanium alloys: fundamentals and applications

    National Research Council Canada - National Science Library

    Leyens, C; Peters, M

    2003-01-01

    ... number of titanium alloys have paved the way for light metals to vastly expand into many industrial applications. Titanium and its alloys stand out primarily due to their high specific strength and excellent corrosion resistance, at just half the weight of steels and Ni-based superalloys. This explains their early success in the aerospace and the...

  1. Studying hardness, workability and minimum bending radius in selectively laser-sintered Ti–6Al–4V alloy samples

    Science.gov (United States)

    Galkina, N. V.; Nosova, Y. A.; Balyakin, A. V.

    2018-03-01

    This research is relevant as it tries to improve the mechanical and service performance of the Ti–6Al–4V titanium alloy obtained by selective laser sintering. For that purpose, sintered samples were annealed at 750 and 850°C for an hour. Sintered and annealed samples were tested for hardness, workability and microstructure. It was found that incomplete annealing of selectively laser-sintered Ti–6Al–4V samples results in an insignificant reduction in hardness and ductility. Sintered and incompletely annealed samples had a hardness of 32..33 HRC, which is lower than the value of annealed parts specified in standards. Complete annealing at temperature 850°C reduces the hardness to 25 HRC and ductility by 15...20%. Incomplete annealing lowers the ductility factor from 0.08 to 0.06. Complete annealing lowers that value to 0.025. Complete annealing probably results in the embrittlement of sintered samples, perhaps due to their oxidation and hydrogenation in the air. Optical metallography showed lateral fractures in both sintered and annealed samples, which might be the reason why they had lower hardness and ductility.

  2. Strengthening and elongation mechanism of Lanthanum-doped Titanium-Zirconium-Molybdenum alloy

    Energy Technology Data Exchange (ETDEWEB)

    Hu, Ping, E-mail: huping1985@126.com [School of Metallurgy Engineering, Xi’an University of Architecture and Technology, Xi’an 710055 (China); Jinduicheng Molybdenum Co., Ltd., Xi’an 710068 (China); Hu, Bo-liang; Wang, Kuai-she; Song, Rui; Yang, Fan [School of Metallurgy Engineering, Xi’an University of Architecture and Technology, Xi’an 710055 (China); Yu, Zhi-tao [Ruifulai Tungsten & Molybdenum Co., Ltd., Xi’an 721914 (China); Tan, Jiang-fei [School of Metallurgy Engineering, Xi’an University of Architecture and Technology, Xi’an 710055 (China); Cao, Wei-cheng; Liu, Dong-xin; An, Geng [Jinduicheng Molybdenum Co., Ltd., Xi’an 710068 (China); Guo, Lei [Ruifulai Tungsten & Molybdenum Co., Ltd., Xi’an 721914 (China); Yu, Hai-liang [School of Mechanical, Materials and Mechatronics Engineering, University of Wollongong, NSW 2522 (Australia)

    2016-12-15

    The microstructural contributes to understand the strengthening and elongation mechanism in Lanthanum-doped Titanium-Zirconium-Molybdenum alloy. Lanthanum oxide particles not only act as heterogeneous nucleation core, but also act as the second phase to hinder the grain growth during sintering crystallization. The molybdenum substrate formed sub-grain under the effect of second phase when the alloy rolled to plate.

  3. Photoluminescence and hydrogen gas-sensing properties of titanium dioxide nanostructures synthesized by hydrothermal treatments

    CSIR Research Space (South Africa)

    Sikhwivhilu, LM

    2012-03-01

    Full Text Available Titanium dioxide (TiO2) nanostructures were synthesized by microwave-assisted and conventionally heated hydrothermal treatment of TiO2 powder. The tubular structures were converted to a rodlike shape by sintering the samples at various temperatures...

  4. 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.

  5. SINTERING OF NASCENT CALCIUM OXIDE

    Science.gov (United States)

    The paper discusses the measurement of the sintering rate of CaO in a nitrogen atmosphere at temperatures of 700-1100 C. CaO prepared from ultrapure CaCO3 was compared with an impure CaO derived from limestone. Both materials yielded an initial surface area of 104 sq m/g. The rat...

  6. Production of a low young modulus titanium alloy by powder metallurgy

    Directory of Open Access Journals (Sweden)

    Dalcy Roberto dos Santos

    2005-12-01

    Full Text Available Titanium alloys have several advantages over ferrous and non-ferrous metallic materials, such as high strengthto-weight ratio and excellent corrosion resistance. A blended elemental titanium powder metallurgy process has been developed to offer low cost commercial products. The process employs hydride-dehydride (HDH powders as raw material. In this work, results of the Ti-35Nb alloy sintering are presented. This alloy due to its lower modulus of elasticity and high biocompatibility is a promising candidate for aerospace and medical use. Samples were produced by mixing of initial metallic powders followed by uniaxial and cold isostatic pressing with subsequent densification by isochronal sintering between 900 up to 1600 °C, in vacuum. Sintering behavior was studied by means of microscopy and density. Sintered samples were characterized for phase composition, microstructure and microhardness by X-ray diffraction, scanning electron microscopy and Vickers indentation, respectively. Samples sintered at high temperatures display a fine plate-like alpha structure and intergranular beta. A few remaining pores are still found and density above 90% for specimens sintered in temperatures over 1500 °C is reached.

  7. Composite materials and bodies including silicon carbide and titanium diboride and methods of forming same

    Science.gov (United States)

    Lillo, Thomas M.; Chu, Henry S.; Harrison, William M.; Bailey, Derek

    2013-01-22

    Methods of forming composite materials include coating particles of titanium dioxide with a substance including boron (e.g., boron carbide) and a substance including carbon, and reacting the titanium dioxide with the substance including boron and the substance including carbon to form titanium diboride. The methods may be used to form ceramic composite bodies and materials, such as, for example, a ceramic composite body or material including silicon carbide and titanium diboride. Such bodies and materials may be used as armor bodies and armor materials. Such methods may include forming a green body and sintering the green body to a desirable final density. Green bodies formed in accordance with such methods may include particles comprising titanium dioxide and a coating at least partially covering exterior surfaces thereof, the coating comprising a substance including boron (e.g., boron carbide) and a substance including carbon.

  8. Introduction to powder metallurgy processes for titanium manufacturing; Introduccion al procesado pulvimetalurgico del titanio

    Energy Technology Data Exchange (ETDEWEB)

    Esteban, P. G.; Bolzoni, L.; Ruiz-Navas, E. M.; Gordo, E.

    2011-07-01

    The development of new extraction processes to produce titanium in powder form leads Powder Metallurgy to an advantage position among the manufacturing processes for titanium. The cost reduction of base material, coupled with the economy of the powder metallurgy processes, give titanium industry the chance to diversify its products, which could lead to production volumes able to stabilise the price of the metal. This work reviews some of the Powder Metallurgy techniques for the manufacturing of titanium parts, and describes the two typical approaches for titanium manufacturing: Blending Elemental and Prealloyed Powders. Among others, conventional pressing and sintering are described, which are compared with cold and hot isostatic pressing techniques. Real and potential applications are described. (Author) 71 refs.

  9. 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 response...... to the stress field as well as the FE calculation of the stress field from the microstructural evolution is discussed. The sintering behavior of two powder compacts constrained by a rigid substrate is simulated and compared to free sintering of the same samples. Constrained sintering result in a larger number...

  10. 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.)

  11. Progress in Titanium Metal Powder Injection Molding

    Directory of Open Access Journals (Sweden)

    Randall M. German

    2013-08-01

    Full Text Available Metal powder injection molding is a shaping technology that has achieved solid scientific underpinnings. It is from this science base that recent progress has occurred in titanium powder injection molding. Much of the progress awaited development of the required particles with specific characteristics of particle size, particle shape, and purity. The production of titanium components by injection molding is stabilized by a good understanding of how each process variable impacts density and impurity level. As summarized here, recent research has isolated the four critical success factors in titanium metal powder injection molding (Ti-MIM that must be simultaneously satisfied—density, purity, alloying, and microstructure. The critical role of density and impurities, and the inability to remove impurities with sintering, compels attention to starting Ti-MIM with high quality alloy powders. This article addresses the four critical success factors to rationalize Ti-MIM processing conditions to the requirements for demanding applications in aerospace and medical fields. Based on extensive research, a baseline process is identified and reported here with attention to linking mechanical properties to the four critical success factors.

  12. Downhole television (DHTV) applications in borehole plugging

    International Nuclear Information System (INIS)

    Christensen, C.L.; Statler, R.D.; Peterson, E.W.

    1980-05-01

    The Borehole Plugging (BHP) Program is a part of the Sandia experimental program to support the Waste Isolation Pilot Plant (WIPP). The Sandia BHP program is an Office of Nuclear Waste Isolation (ONWI)-funded program designed to provide inputs to the generic plugging program while simultaneously acquiring WIPP-specific data. For this reason a close liaison is maintained between the Sandia WIPP project and the ONWI generic program. Useful technology developed within the Sandia BHP to support WIPP is made available and considered for further development and application to the generic Borehole Plugging and Repository Sealing Program at ONWI. The purpose of this report is to illustrate the usefulness of downhole television (DHTV) observations of a borehole to plan plugging operations. An indication of the wellbore conditions observed is provided. The equipment and setup procedure used in the evaluation of AEC-7 for the Bell Canyon test series are illustrated. A sequence of pictures at various depths as the DHTV rig is lowered through the wellbore is presented. Sample photographs taken with both dry and underwater lamps for illumination are included. The caliper logs for the same depth are included for comparison. General comments are provided on the illustrations

  13. FY-1979 progress report. Hydrotransport plugging study.

    Energy Technology Data Exchange (ETDEWEB)

    Eyler, L.L.; Lombardo, N.J.

    1980-01-01

    The objective of the Hydrotransport Plugging Study is to investigate phenomena associated with predicting the onset and occurrence of plugging in pipeline transport of coal. This study addresses large particle transport plugging phenomena that may be encountered in run-of-mine operations. The project is being conducted in four tasks: review and analysis of current capabilities and available data, analytical modeling, experimental investigations, and unplugging and static start-up. This report documents work completed in FY-1979 as well as work currently in progress. A review of currently available prediction methods was completed. Applicability of the methods to large particle hydrotransport and the prediction of plugging was evaluated. It was determined that available models were inadequate, either because they are empirical and tuned to a given solid or because they are simplified analytical models incapable of accounting for a wide range of parameters. Complicated regression curve fit models lacking a physical basis cannot be extrapolated with confidence. Several specific conclusions were reached: Recent developments in mechanistic modeling, describing flow conditions at the limit of stationary deposition, provide the best basis for prediction and extrapolation of large particle flow. Certain modeled phenomena require further analytical and experimental investigation to improve confidence levels. Experimental work needs to be performed to support modeling and to provide an adequate data base for comparison purposes. No available model permits treatment of solids mixtures such as coal and rock.

  14. An Overview of the HomePlug AV2 Technology

    Directory of Open Access Journals (Sweden)

    Larry Yonge

    2013-01-01

    Full Text Available HomePlug AV2 is the solution identified by the HomePlug Alliance to achieve the improved data rate performance required by the new generation of multimedia applications without the need to install extra wires. Developed by industry-leading participants in the HomePlug AV Technical Working Group, the HomePlug AV2 technology provides Gigabit-class connection speeds over the existing AC wires within home. It is designed to meet the market demands for the full set of future in-home networking connectivity. Moreover, HomePlug AV2 guarantees backward interoperability with other HomePlug systems. In this paper, the HomePlug AV2 system architecture is introduced and the technical details of the key features at both the PHY and MAC layers are described. The HomePlug AV2 performance is assessed, through simulations reproducing real home scenarios.

  15. Plug-in hybrid electric vehicle R&D plan

    Energy Technology Data Exchange (ETDEWEB)

    None, None

    2007-06-01

    FCVT, in consultation with industry and other appropriate DOE offices, developed the Draft Plug-In Hybrid Electric Vehicle R&D Plan to accelerate the development and deployment of technologies critical for plug-in hybrid vehicles.

  16. Vacuum-sintered body of a novel apatite for artificial bone

    Science.gov (United States)

    Tamura, Kenichi; Fujita, Tatsushi; Morisaki, Yuriko

    2013-12-01

    We produced regenerative artificial bone material and bone parts using vacuum-sintered bodies of a novel apatite called "Titanium medical apatite (TMA®)" for biomedical applications. TMA was formed by chemically connecting a Ti oxide molecule with the reactive [Ca10(PO4)6] group of Hydroxyapatite (HAp). The TMA powders were kneaded with distilled water, and solid cylinders of compacted TMA were made by compression molding at 10 MPa using a stainless-steel vessel. The TMA compacts were dried and then sintered in vacuum (about 10-3 Pa) or in air using a resistance heating furnace in the temperature range 1073-1773 K. TMA compacts were sintered at temperatures greater than 1073 K, thus resulting in recrystallization. The TMA compact bodies sintered in the range 1273-1773 K were converted into mixtures composed of three crystalline materials: α-TCP (tricalcium phosphate), β-TCP, and Perovskite-CaTiO3. The Perovskite crystals were stable and hard. In vacuum-sintering, the Perovskite crystals were transformed into fibers (approximately 1 µm in diameter × 8 µm in length), and the fiber distribution was uniform in various directions. We refer to the TMA vacuum-sintered bodies as a "reinforced composite material with Perovskite crystal fibers." However, in atmospheric sintering, the Perovskite crystals were of various sizes and were irregularly distributed as a result of the effect of oxygen. After sintering temperature at 1573 K, the following results were obtained: the obtained TMA vacuum-sintered bodies (1) were white, (2) had a density of approximately 2300 kg/m3 (corresponding to that of a compact bone or a tooth), and had a thermal conductivity of approximately 31.3 W/(m·K) (corresponding to those of metal or ceramic implants). Further, it was possible to cut the TMA bodies into various forms with a cutting machine. An implant made of TMA and inserted into a rabbit jaw bone was covered by new bone tissues after just one month because of the high

  17. An optimal design for millimeter-wide facture plugging zone

    Directory of Open Access Journals (Sweden)

    Yili Kang

    2015-01-01

    Full Text Available Lost circulation control in millimeter-wide fractures has been a challenge in well drilling all the time. Low pressure-bearing capacity of a plugging zone will result in excessive consumption of lost circulation materials (LCMs and extra down time. In this study, laboratory experiments were conducted on the plugging of millimeter-wide fractures to evaluate the plugging effects of different types of LCM including rigid granules, elastic particles and fiber. Maximum plugging pressure, total loss volume before sealing and plugging time were taken as the evaluation index of the LCM plugging effect. According to the experimental results, the synergistic plugging mechanisms of different LCM combinations were also analyzed. Experimental results showed that the total loss volume of the plugging zone formed by rigid and elastic particle combination was generally greater than 400 mL, and the maximum plugging pressure of the plugging zone formed by elastic particle and fiber combination was generally less than 6 MPa. In contrast, the plugging zone formed by the combination of the three types of LCMs has the maximum plugging pressure of up to 13 MPa and total loss volume before sealing of 75 mL. In the synergistic plugging process, rigid granules form a frame with high pressure-bearing capacity in the narrower parts of the fractures; elastic particles generate elastic force through elastic deformation to increase the friction between a fracture and a plugging zone to make the plugging zone more stable; fibers filling in the pore space between the particles increase the tightness and integrity of the plugging zone. The experimental results can provide guidance for the optimal design of LCMs used in the field.

  18. Bond strength of cementitious borehole plugs in welded tuff

    International Nuclear Information System (INIS)

    Akgun, H.; Daemen, J.J.K.

    1991-02-01

    Axial loads on plugs or seals in an underground repository due to gas, water pressures and temperature changes induced subsequent to waste and plug emplacement lead to shear stresses at the plug/rock contact. Therefore, the bond between the plug and rock is a critical element for the design and effectiveness of plugs in boreholes, shafts or tunnels. This study includes a systematic investigation of the bond strength of cementitious borehole plugs in welded tuff. Analytical and numerical analysis of borehole plug-rock stress transfer mechanics is performed. The interface strength and deformation are studied as a function of Young's modulus ratio of plug and rock, plug length and rock cylinder outside-to-inside radius ratio. The tensile stresses in and near an axially loaded plug are analyzed. The frictional interface strength of an axially loaded borehole plug, the effect of axial stress and lateral external stress, and thermal effects are also analyzed. Implications for plug design are discussed. The main conclusion is a strong recommendation to design friction plugs in shafts, drifts, tunnels or boreholes with a minimum length to diameter ratio of four. Such a geometrical design will reduce tensile stresses in the plug and in the host rock to a level which should minimize the risk of long-term deterioration caused by excessive tensile stresses. Push-out tests have been used to determine the bond strength by applying an axial load to cement plugs emplaced in boreholes in welded tuff cylinders. A total of 130 push-out tests have been performed as a function of borehole size, plug length, temperature, and degree of saturation of the host tuff. The use of four different borehole radii enables evaluation of size effects. 119 refs., 42 figs., 20 tabs

  19. 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.

  20. Installation of the backfill and plug test

    International Nuclear Information System (INIS)

    Gunnarsson, D.; Borgesson, L.; Hokmark, H.; Hohannesson, L.E.; Sanden, T.

    2003-01-01

    The Backfill and Plug Test is a full scale test of backfill material, backfilling technique and a tunnel plug. The main objectives of the Backfill and Plug Test are: - to develop and test different materials and compaction techniques for backfilling of tunnels excavated by blasting; - to test the function of the backfill and its interaction with the surrounding rock in a tunnel excavated by blasting; - to develop technique for building tunnel plugs and to test the function. The installation was made in the Swedish underground laboratory, Aspo HRL, during 1999. The inner part of the tunnel is not used for the test but was filled with drainage material. The test volume, which is about 28 m long, can be divided into the following three parts: - the inner part filled with backfill containing 30% bentonite; - the outer part filled with backfill without bentonite and bentonite blocks and pellets at the roof; - the plug. Permeable layers divide the test volume into 11 test sections. The permeable layers are used for increasing the water saturation rate in the backfill and for applying hydraulic gradients between the layers for studying the flow of water in the backfill and in the near field rock. The permeable layers were installed every 2.2 m and each layer is divided into three units in order to separately measure the flow close to the roof, in the central areas of the tunnel and close to the floor. The outer part ends with a wall of prefabricated concrete beams that were used for temporary support of the backfill during the casting of the plug. The upper volume close to the plug is filled with bentonite pellets and blocks consisting of 20% bentonite and 80% sand. The backfill is instrumented with 34 pore water pressure cells, 21 total pressure cells, 57 sensors for monitoring the water saturation and 13 gauges for measuring the local hydraulic conductivity. The water pressures in the permeable mats are measured in all sections. Four pressure cylinders, 2 in the roof

  1. Recent developments in plugging of steam generator tubes

    International Nuclear Information System (INIS)

    Buhay, S.; Abucay, R.C.

    1995-01-01

    Mechanical Plugging capability has been developed for Bruce Nuclear Generating Station (BNGS) steam generator (SG) tubes and Darlington Nuclear Generating Station (DNGS) SG tubes and tubesheet holes. The plug concept was a modified ABB/Combustion Engineering Inconel 690 plug with a nickel band, rolled into the tube or tubesheet hole from the primary side of the tubesheet. The qualification program included analytical justification of the plug body and experimental testing to verify the leak tightness of the rolled joint under conditions which meet or exceed all service or design requirements. Tools and procedures were developed and tested for manual and remote/robotic installation and removal of the mechanical plugs. Additionally, tools and procedures were developed to plug tubes/tubesheet holes at DNGS in the event the steam generator is recalled to service to act as a heat sink. A crew of Ontario Hydro personnel were trained and qualified for the installation of mechanical plugs for permanent and recall applications. During the DNGS Unit 4 spring 1995 outage, 6 tubes were plugged and the 'Recall Plugging Capability' was deployed and ready for use during a primary side SG tube removal. The mechanical plugs were installed manually with a typical 3 minute/plug in-bowl duration time with an average radiation dose of 12.5 mrem per plug. This compares favourably with manual plug welding during the same outage in the same SG bowl at approximately 15-30 minutes/plug in-bowl duration with an average radiation dose of 117 mrem/plug. (author)

  2. Plugging of feed inlet tube upstands with Ni/Ti shape memory alloy plugs - Heysham 1 power station

    International Nuclear Information System (INIS)

    Mathews, A.J.

    1988-01-01

    The paper contains a description of a new approach for Plugging feed inlet tubes of Gas-Cooled Reactors. Instead of utilizing the original explosive method plugging by fitting a shape memory alloy plug into the upstand is being described. (author)

  3. Sintering of ZrC by hot isostatic pressing (HIP) and spark plasma sintering (SPS). Effect of impurities

    International Nuclear Information System (INIS)

    Allemand, Alexandre; Le Flem - Dormeval, Marion; Guillard, Francois

    2005-01-01

    Carbides are generally used as structural materials for high temperature applications. Particularly, ZrC because of low activation, neutronic transparency, cubic structure (isotropic behaviour) and good thermal conductivity, is one of the candidates under consideration for structural materials in the core of new high temperature nuclear reactors (Generation IV). Just a few studies about densification of monolithic ZrC exist. They mainly involve natural sintering or hot pressing at high temperature (until 2700 deg. C). Unfortunately those processes induce grain growth and do not lead to fully densified ZrC. The aim of this study is to compare the characteristics and the properties of ZrC sintered by HIP and by SPS. Fully dense ZrC can be reached either by HIP or by SPS, grain size being more or less controlled. Microstructural observations and mechanical testing of several ZrC grades shows that powder impurities play an important role in the quality of the grain boundaries and consequently in the mechanical properties. In particular, the porosity falls from 17% to 3 % just by reducing the free carbon content in starting ZrC powder. The densification process of dense monolithic ZrC was improved by combining a HIP at 1600 deg. C (titanium canning) followed by a post-HIP at 1900 deg. C (no canning required). Four-point bending tests are in progress to confirm the improvement of fracture strength. (authors)

  4. Modeling of sintering of functionally gradated materials

    International Nuclear Information System (INIS)

    Gasik, M.; Zhang, B.

    2001-01-01

    The functionally gradated materials (FGMs) are distinguished from isotropic materials by gradients of composition, phase distribution, porosity, and related properties. For FGMs made by powder metallurgy, sintering control is one of the most important factors. In this study sintering process of FGMs is modeled and simulated with a computer. A new modeling approach was used to formulate equation systems and the model for sintering of gradated hard metals, coupled with heat transfer and grain growth. A FEM module was developed to simulate FGM sintering in conventional, microwave and hybrid conditions, to calculate density, stress and temperature distribution. Behavior of gradated WC-Co hardmetal plate and cone specimens was simulated for various conditions, such as mean particle size, green density distribution and cobalt gradation parameter. The results show that the deformation behavior and stress history of graded powder compacts during heating, sintering and cooling could be predicted for optimization of sintering process. (author)

  5. 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

  6. Intrinsic Osteoinductivity of Porous Titanium Scaffold for Bone Tissue Engineering

    Directory of Open Access Journals (Sweden)

    Maryam Tamaddon

    2017-01-01

    Full Text Available Large bone defects and nonunions are serious complications that are caused by extensive trauma or tumour. As traditional therapies fail to repair these critical-sized defects, tissue engineering scaffolds can be used to regenerate the damaged tissue. Highly porous titanium scaffolds, produced by selective laser sintering with mechanical properties in range of trabecular bone (compressive strength 35 MPa and modulus 73 MPa, can be used in these orthopaedic applications, if a stable mechanical fixation is provided. Hydroxyapatite coatings are generally considered essential and/or beneficial for bone formation; however, debonding of the coatings is one of the main concerns. We hypothesised that the titanium scaffolds have an intrinsic potential to induce bone formation without the need for a hydroxyapatite coating. In this paper, titanium scaffolds coated with hydroxyapatite using electrochemical method were fabricated and osteoinductivity of coated and noncoated scaffolds was compared in vitro. Alizarin Red quantification confirmed osteogenesis independent of coating. Bone formation and ingrowth into the titanium scaffolds were evaluated in sheep stifle joints. The examinations after 3 months revealed 70% bone ingrowth into the scaffold confirming its osteoinductive capacity. It is shown that the developed titanium scaffold has an intrinsic capacity for bone formation and is a suitable scaffold for bone tissue engineering.

  7. Industry perspectives on Plug-& -Play Spacecraft Avionics

    Science.gov (United States)

    Franck, R.; Graven, P.; Liptak, L.

    This paper describes the methodologies and findings from an industry survey of awareness and utility of Spacecraft Plug-& -Play Avionics (SPA). The survey was conducted via interviews, in-person and teleconference, with spacecraft prime contractors and suppliers. It focuses primarily on AFRL's SPA technology development activities but also explores the broader applicability and utility of Plug-& -Play (PnP) architectures for spacecraft. Interviews include large and small suppliers as well as large and small spacecraft prime contractors. Through these “ product marketing” interviews, awareness and attitudes can be assessed, key technical and market barriers can be identified, and opportunities for improvement can be uncovered. Although this effort focuses on a high-level assessment, similar processes can be used to develop business cases and economic models which may be necessary to support investment decisions.

  8. CDF End Plug calorimeter Upgrade Project

    International Nuclear Information System (INIS)

    Apollinari, G.; de Barbaro, P.; Mishina, M.

    1994-01-01

    We report on the status of the CDF End Plug Upgrade Project. In this project, the CDF calorimeters in the end plug and the forward regions will be replaced by a single scintillator based calorimeter. After an extensive R ampersand D effort on the tile/fiber calorimetry, we have now advanced to a construction phase. We review the results of the R ampersand D leading to the final design of the calorimeters and the development of tooling devised for this project. The quality control program of the production of the electromagnetic and hadronic calorimeters is described. A shower maximum detector for the measurement of the shower centroid and the shower profile of electrons, γ and π 0 has been designed. Its performance requirements, R ampersand D results and mechanical design are discussed

  9. A study for preparation of Ti-Fe coating by high temperature sintering method

    International Nuclear Information System (INIS)

    Hu Yonghai

    1995-03-01

    A new technology for preparation of Ti-Fe alloy coating on the steel substrate was investigated by high temperature sintering method. The pulp of titanium hydride powder was coated on the cleaned steel substrate, then heated in vacuum for desorption of hydrogen and sintered at high temperature in argon atmosphere for forming Ti-Fe alloy coating. The electron probe analysis shows a strong coherent diffusion layer formed between the elements of titanium and iron. X-ray diffraction analysis indicates that the coating consists of α-Ti, TiFe and TiFe 2 three phases. The wear resistance of the coating is twice as large as that of grey cast iron and the hardness determined can reach 7300∼7800 N/mm 2 . The coating is almost porous free. The corrosion potential increases with the time and the corrosion resistance is near to that of pure titanium. The working life of ridge-type diaphragm valve coated by Ti-Fe alloy for carbonization tower of alkali factories is five times higher than that of valve made of grey cast iron. Therefore, this new technology can be widely used in metallurgical, chemical and nuclear industries. (9 figs., 10 tabs.)

  10. Resistance of direct metal laser sintered Ti6Al4V alloy against growth of fatigue cracks

    Czech Academy of Sciences Publication Activity Database

    Konečná, R.; Kunz, Ludvík; Bača, A.; Nicoletto, G.

    2017-01-01

    Roč. 185, NOV (2017), s. 82-91 ISSN 0013-7944 Institutional support: RVO:68081723 Keywords : Titanium alloys * Ti6Al4V * Fatigue crack growth * Threshold value of stress intensity factor * Direct metal laser sintering Subject RIV: JL - Materials Fatigue, Friction Mechanics OBOR OECD: Audio engineering, reliability analysis Impact factor: 2.151, year: 2016 http://www.sciencedirect.com/science/article/pii/S0013794417300292

  11. Microwave sintering of hydroxyapatite-based composites

    International Nuclear Information System (INIS)

    Fang, Y.; Roy, D.M.; Cheng, J.; Roy, R.; Agrawal, D.K.

    1993-01-01

    Composites of hydroxyapatite/partially stabilized zirconia (HAp/PSZ) and hydroxyapatite/silicon carbide whiskers (HAp/SiC) were sintered at 1100-1200 degrees C by microwave at 2.45 GHz. Characterization of the sintered composites was carried out by density, microstructure, phase composition, and fracture toughness measurements. The results show that although not yet fully densified, a much higher sintered density in the HAp/PSZ composite was achieved by microwave sintering than by conventional sintering at the same temperature. A relative density of 93% was achieved by 20 min. microwave processing at 1200 degrees C. Comparatively, 2 h conventional sintering of the same material at 1200 degrees C led to only 75.5% relative density. K IC of this microwave sintered HAp/PSZ of 93% density was found to be 3.88 MPa√m, which is 250% of the value for pure HAp of the same density. A further increase in K IC could be expected if full or nearly full densification was achieved. Sintering of PSZ particles in the HAp/PSZ composite was also observed in the microwave processed sample. Microwave sintering of HAp/SiC was not successful in the current study due to the oxidation of SiC in air at high temperature. 8 refs., 4 figs., 1 tab

  12. Sintering of a class F fly ash

    Energy Technology Data Exchange (ETDEWEB)

    Joseph J. Biernacki; Anil K. Vazrala; H. Wayne Leimer [Tennessee Technological University, Cookeville, TN (United States). Department of Chemical Engineering

    2008-05-15

    The sinterability of a class F fly ash was investigated as a function of processing conditions including sintering temperature (1050-1200{sup o}C) and sintering time (0-90 min). Density, shrinkage, splitting tensile strength, water absorption and residual loss on ignition (RLOI) were evaluated as measures of sintering efficiency. Scanning electron microscopy (SEM), X-ray microanalysis and X-ray diffraction was used to examine microstructure and phase development due to processing. The results show that premature densification can inhibit complete carbon removal and that carbon combustion is influenced by both internal and external mass transfer conditions. 18 refs., 10 figs., 1 tab.

  13. Sealing glasses for titanium and titanium alloys

    Science.gov (United States)

    Brow, Richard K.; McCollister, Howard L.; Phifer, Carol C.; Day, Delbert E.

    1997-01-01

    Barium lanthanoborate sealing-glass compositions are provided comprising various combinations (in terms of mole-%) of boron oxide (B.sub.2 O.sub.3), barium oxide (BaO), lanthanum oxide (La.sub.2 O.sub.3), and at least one other oxide selected from the group consisting of aluminum oxide (Al.sub.2 O.sub.3), calcium oxide (CaO), lithium oxide (Li.sub.2 O), sodium oxide (Na.sub.2 O), silicon dioxide (SiO.sub.2), or titanium dioxide (TiO.sub.2). These sealing-glass compositions are useful for forming hermetic glass-to-metal seals with titanium and titanium alloys having an improved aqueous durability and favorable sealing characteristics. Examples of the sealing-glass compositions are provided having coefficients of thermal expansion about that of titanium or titanium alloys, and with sealing temperatures less than about 900.degree. C., and generally about 700.degree.-800.degree. C. The barium lanthanoborate sealing-glass compositions are useful for components and devices requiring prolonged exposure to moisture or water, and for implanted biomedical devices (e.g. batteries, pacemakers, defibrillators, pumps).

  14. Cost estimate for electrostatically plugged cusp reactor

    International Nuclear Information System (INIS)

    Dolan, T.J.

    1977-01-01

    A preliminary design of an electrostatically plugged cusp reactor was presented in (UCRL-52142(1976)). The capital costs of the various components of this reactor are estimated and totaled for two different blanket configurations: one having an energy multiplication factor M = 1.2, and the other having M = 1.68. The unoptimized direct capital costs for these cases are found to be about 1400 and 950 $/kWe, respectively

  15. Borehole plugging by hydrothermal transport. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Roy, D.M.; White, W.B.

    1976-02-28

    Calcium silicate--and aluminosilicate--compositions based on mixtures of fine grained quartz with various cements or calcium silicate compounds have been investigated under hydrothermal conditions in the temperature range 110-250/sup 0/C and pressure range 1,000-10,000 psi, pressures which are always in excess of that required to maintain liquid H/sub 2/O, and approximate the confining pressures which might be anticipated in deep boreholes. All silicate cement combinations investigated produce materials having adequate strength after reaction times of 1 day or longer. The calcium aluminate cement was also adequate with respect to strength but would need to be investigated more extensively for overall properties because of its highly reactive chemistry. The mini-rock cylinder-cement plug hydrothermal experiments in both limestone and sandstone resulted in reasonable magnitudes of bonding strength. The typical shear strength of a hydrothermally treated cement-sandstone plug is 1030 psi, and the compressive strength of the extruded cement plug is 9550 psi. Reactions having a potential for producing calcium carbonate plugs in holes drilled in carbonate rocks were studied. It should be noted that most cements are calcium silicate systems and are chemically compatible with the CaCO/sub 3/ and CaMg(CO/sub 3/)/sub 2/ in the rock walls of the hole. A side benefit from this research is some insight into the suitability of massive carbonate rocks as disposal sites. Carbonate rocks by themselves are highly impermeable, have low exchange capacity, and a low water content--all properties that are desirable in the storage medium. A major drawback is the presence of secondary permeability in the form of solutionally modified joints, fractures, and bedding planes.

  16. Borehole plugging by hydrothermal transport. Final report

    International Nuclear Information System (INIS)

    Roy, D.M.; White, W.B.

    1976-01-01

    Calcium silicate--and aluminosilicate--compositions based on mixtures of fine grained quartz with various cements or calcium silicate compounds have been investigated under hydrothermal conditions in the temperature range 110-250 0 C and pressure range 1,000-10,000 psi, pressures which are always in excess of that required to maintain liquid H 2 O, and approximate the confining pressures which might be anticipated in deep boreholes. All silicate cement combinations investigated produce materials having adequate strength after reaction times of 1 day or longer. The calcium aluminate cement was also adequate with respect to strength but would need to be investigated more extensively for overall properties because of its highly reactive chemistry. The mini-rock cylinder-cement plug hydrothermal experiments in both limestone and sandstone resulted in reasonable magnitudes of bonding strength. The typical shear strength of a hydrothermally treated cement-sandstone plug is 1030 psi, and the compressive strength of the extruded cement plug is 9550 psi. Reactions having a potential for producing calcium carbonate plugs in holes drilled in carbonate rocks were studied. It should be noted that most cements are calcium silicate systems and are chemically compatible with the CaCO 3 and CaMg(CO 3 ) 2 in the rock walls of the hole. A side benefit from this research is some insight into the suitability of massive carbonate rocks as disposal sites. Carbonate rocks by themselves are highly impermeable, have low exchange capacity, and a low water content--all properties that are desirable in the storage medium. A major drawback is the presence of secondary permeability in the form of solutionally modified joints, fractures, and bedding planes

  17. Plug and abandonment operations and tool positioning

    OpenAIRE

    Saad, Idrees

    2014-01-01

    Master's thesis in Petroleum engineering With aging oil fields, the Norwegian petroleum authorities are focusing on Plug and Abandonment (P&A) plans. Therefore efforts are being made, by relevant authorities, to improve standards and procedures for the P&A operations. Regulations for UK part of the North Sea define the P&A operation plans and execution phases in a way that may help improve the standards on the Norwegian Continental Shelf. Halliburton like its competitors is focusing on ...

  18. Development of simplified rotating plug seal structure

    International Nuclear Information System (INIS)

    Ueta, M.; Ichimiya, M.; Kanaoka, T.; Sekiya, H.; Ueda, S.; Ishibashi, S.

    1991-01-01

    We studied a compact and simplified rotating plug seal structure and conducted experiments for key elements of the concept such us the mechanical seal structure and sodium deposit prevention system. Good characteristics were confirmed for the mechanical seal structure, which utilizes an elastomer seal and thin lathe bearing. Applicability of the density barrier concept was also confirmed as the sodium deposit prevention system. This concept can be applied to actual plants. (author)

  19. Ice plugging of pipes using liquid nitrogen

    International Nuclear Information System (INIS)

    Twigg, R.J.

    1987-03-01

    This report presents a study on the ice plugging of pipe using liquid nitrogen, and is based on a literature review and on discussions with individuals who use the technique. Emphasis is placed on ferritic alloys, primarily carbon steels, in pipe sized up to 60 cm in diameter and on austenitic stainless steels in pipe sizes up to 30 cm in diameter. This technique is frequently used for leak testing in nuclear facilities

  20. Borehole Plugging-Materials Development Program

    International Nuclear Information System (INIS)

    Gulick, C.W. Jr.

    1978-06-01

    This report discusses the background and first year's results of the grouting materials development program for plugging boreholes associated with the Nuclear Waste Isolation Pilot Plant. The grouts are to be pumpable, impermeable, and durable for many thousands of years. The work was done at the Concrete Laboratory of the U.S. Army Engineer Waterways Experiment Station (WES), Vicksburg, Mississippi. The workability, strength, porosity, bonding, expansion, and permeability data are summarized and discussed. The work is continuing at WES

  1. 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

  2. Classification of titanium dioxide

    International Nuclear Information System (INIS)

    Macias B, L.R.; Garcia C, R.M.; Maya M, M.E.; Ita T, A. De; Palacios G, J.

    2002-01-01

    In this work the X-ray diffraction (XRD), Scanning Electron Microscopy (Sem) and the X-ray Dispersive Energy Spectroscopy techniques are used with the purpose to achieve a complete identification of phases and mixture of phases of a crystalline material as titanium dioxide. The problem for solving consists of being able to distinguish a sample of titanium dioxide being different than a titanium dioxide pigment. A standard sample of titanium dioxide with NIST certificate is used, which indicates a purity of 99.74% for the TiO 2 . The following way is recommended to proceed: a)To make an analysis by means of X-ray diffraction technique to the sample of titanium dioxide pigment and on the standard of titanium dioxide waiting not find differences. b) To make a chemical analysis by the X-ray Dispersive Energy Spectroscopy via in a microscope, taking advantage of the high vacuum since it is oxygen which is analysed and if it is concluded that the aluminium oxide appears in a greater proportion to 1% it is established that is a titanium dioxide pigment, but if it is lesser then it will be only titanium dioxide. This type of analysis is an application of the nuclear techniques useful for the tariff classification of merchandise which is considered as of difficult recognition. (Author)

  3. Microstructure and Mechanical Properties of Graphene-Reinforced Titanium Matrix/Nano-Hydroxyapatite Nanocomposites.

    Science.gov (United States)

    Li, Feng; Jiang, Xiaosong; Shao, Zhenyi; Zhu, Degui; Zhu, Minhao

    2018-04-16

    Biomaterial composites made of titanium and hydroxyapatite (HA) powder are among the most important biomedicalmaterials due to their good mechanical properties and biocompatibility. In this work, graphene-reinforced titanium matrix/nano-hydroxyapatite nanocomposites were prepared by vacuum hot-pressing sintering. The microstructure and mechanical properties of graphene-reinforced titanium matrix/nano-hydroxyapatite nanocomposites with different graphene content were systematically investigated. Microstructures of the nanocomposites were examined by X-ray diffraction (XRD), back scattered electron imaging (BSE), scanning electron microscope (SEM) equipped with energy dispersive spectrometer (EDS), electron probe microanalyzer (EPMA), and transmission electron microscope (TEM). The mechanical properties were determined from microhardness, shear strength, and compressive strength. Results showed that during the high-temperature sintering process, complex chemical reactions occurred, resulting in new phases of nucleation such as Ca₃(PO₄)₂, Ti x P y , and Ti₃O.The new phases, which easily dropped off under the action of external force, could hinder the densification of sintering and increase the brittleness of the nanocomposites. Results demonstrated that graphene had an impact on the microstructure and mechanical properties of the nanocomposites. Based on the mechanical properties and microstructure of the nanocomposites, the strengthening and fracture mechanisms of the graphene-reinforced titanium matrix/nano-hydroxyapatite nanocomposites with different graphene content were analyzed.

  4. Microstructure and Mechanical Properties of Graphene-Reinforced Titanium Matrix/Nano-Hydroxyapatite Nanocomposites

    Directory of Open Access Journals (Sweden)

    Feng Li

    2018-04-01

    Full Text Available Biomaterial composites made of titanium and hydroxyapatite (HA powder are among the most important biomedicalmaterials due to their good mechanical properties and biocompatibility. In this work, graphene-reinforced titanium matrix/nano-hydroxyapatite nanocomposites were prepared by vacuum hot-pressing sintering. The microstructure and mechanical properties of graphene-reinforced titanium matrix/nano-hydroxyapatite nanocomposites with different graphene content were systematically investigated. Microstructures of the nanocomposites were examined by X-ray diffraction (XRD, back scattered electron imaging (BSE, scanning electron microscope (SEM equipped with energy dispersive spectrometer (EDS, electron probe microanalyzer (EPMA, and transmission electron microscope (TEM. The mechanical properties were determined from microhardness, shear strength, and compressive strength. Results showed that during the high-temperature sintering process, complex chemical reactions occurred, resulting in new phases of nucleation such as Ca3(PO42, TixPy, and Ti3O.The new phases, which easily dropped off under the action of external force, could hinder the densification of sintering and increase the brittleness of the nanocomposites. Results demonstrated that graphene had an impact on the microstructure and mechanical properties of the nanocomposites. Based on the mechanical properties and microstructure of the nanocomposites, the strengthening and fracture mechanisms of the graphene-reinforced titanium matrix/nano-hydroxyapatite nanocomposites with different graphene content were analyzed.

  5. Dielectric Properties of Sol-Gel Derived Barium Strontium Titanate and Microwave Sintering of Ceramics

    Science.gov (United States)

    Selmi, Fathi A.

    This thesis consists of two areas of research: (1) sol-gel processing of Ba_{rm 1-x}Sr_{rm x} TiO_3 ceramics and their dielectric properties measurement; and (2) microwave versus conventional sintering of ceramics such as Al_2 O_3, Ba_{ rm 1-x}Sr_{rm x}TiO_3, Sb-doped SnO _2 and YBa_2Cu _3O_7. Sol-gel powders of BaTiO_3, SrTiO_3, and their solid solutions were synthesized by the hydrolysis of titanium isopropoxide and Ba and Sr methoxyethoxides. The loss tangent and dielectric constant of both sol-gel and conventionally prepared and sintered Ba_{rm 1-x}Sr _{rm x}TiO _3 ceramics were investigated at high frequencies. The sol-gel prepared ceramics showed higher dielectric constant and lower loss compared to those prepared conventionally. Ba _{rm 1-x}Sr _{rm x}TiO_3 ceramics were tunable with applied bias, indicating the potential use of this material for phase shifter applications. Porous Ba_{0.65}Sr _{0.35}TiO_3 was also investigated to lower the dielectric constant. Microwave sintering of alpha -Al_2O_3 and SrTiO_3 was investigated using an ordinary kitchen microwave oven (2.45 GHz; 600 Watts). The use of microwaves with good insulation of alpha -Al_2O_3 and SrTiO_3 samples resulted in their rapid sintering with good final densities of 96 and 98% of the theoretical density, respectively. A comparison of grain size for conventionally and microwave sintered SrTiO_3 samples did not show a noticeable difference. However, the grain size of microwave sintered alpha-Al_2O _3 was found to be larger than that of conventionally sintered sample. These results show that rapid sintering of ceramics can be achieved by using microwave radiation. The sintering behavior of coprecipitated Sb-doped SnO_2 was investigated using microwave power absorption. With microwave power, samples were sintered at 1450^circC for 20 minutes and showed a density as high as 99.9% of theoretical. However, samples fired in a conventional electric furnace at the same temperature for 4 hours showed only

  6. Effects of sintering temperature on the density and porosity

    African Journals Online (AJOL)

    2013-03-01

    bonding) between the salt beads at all the temperatures in which sintering was performed. .... and the sintering of some covalent solids and low- stability ceramics. The entire sintering process is gen- erally considered to occur in ...

  7. Remote Handling behind port plug in ITER

    International Nuclear Information System (INIS)

    Bede, O.; Neuberger, H.

    2006-01-01

    Different Test Blanket Modules (TBM) will be used in succession in the same equatorial ports of ITER. The remote handling operations for connection/disconnection of an interface between the port plug of the EU-HCPB-TBM and the port cell equipment are investigated with the goal to reach a quick and simple TBM exchange procedure. This paper describes the operations and systems which are required for connection of the TBM to its supply lines at this interface. The interface is located inside the free space of the port plug flange between the port plug shield and the bioshield of the port cell behind. The approach of the operation place is only available through a narrow gate in the bioshield opened temporarily during maintenance periods. This gate limits the dimensions of the whole system and its tools. The current design of the EU-HCPB-TBM foresees up to 9 supply lines which have to be connected inside the free space of one half of the port plug flange. The connection operations require positioning and adjustment of the tools for each pipe separately. Despite the strict circumstances it is still possible to find such an industrial jointed-arm robot with sufficient payload, which can penetrate into the working area. A mechanical system is necessary to move the robot from its storing place in the hot cell to the port plug on 6 m distance. Each operation requires different end-of-arm tools. The most special one is a pipe positioner tool, which can position and pull the pipe ends to each other and align the tool before welding and hold them in proper position during the welding process. Weld seams can be made by orbital welding tool. The pipe positioner tool has to provide place for welding tool. Using of inbore tool is impossible because pipes have no open ends where the tool could leave it. Orbital tool must be modified to meet requirements of remote handling because it is designed for human handling. The coolant is helium, so for eliminating the leak of helium it is

  8. Electrowinning molten titanium from titanium dioxide

    CSIR Research Space (South Africa)

    Van Vuuren, DS

    2005-10-01

    Full Text Available the Manufacturing and Materials Industry in it quest for global competitiveness CSIR Manufacturing and Materials Technology 3 Rationale – Titanium Cost Build-up Material Cost Ilmenite $0.27/kg Ti sponge Titanium slag $0.75/kg Ti Sponge TiCl4 and TiO2 $3....10/kg Ti Sponge Ti Sponge raw materials costs $5.50/kg Ti Sponge Total Ti Sponge cost $9-$11/kg Ti Sponge Ti ingot $15-17/kg Ti Aluminium $1.7/kg Al Supporting the Manufacturing and Materials Industry in its quest for global competitivenessorting...

  9. Mechanism of Randall’s Plugs Development

    Directory of Open Access Journals (Sweden)

    Felix Grases

    2017-09-01

    Full Text Available Mechanism of formation and development of intraluminal concretion, also called Randall's plug, extracted from a female patient forming calcium oxalate dihydrate (COD calculi was examined. Some of these calculi were connected to the papillary tip, and had connections with the interior of the papilla with finger-like extensions in the collecting duct (CD. The intraluminal concretion consisted of inter-grown COD crystals of irregular size (30–100 μm, approximately 5% of biological hydroxyapatite (BHAP and an organic matter. Urine of the patient was moderately supersaturated with respect to COD and amorphous calcium phosphate (ACP. Model of kidney, recently refined by Robertson, was used in calculations. Calculated Reynolds number indicated that the flow of liquid through tubules was purely laminar with parabolic velocity profile. COD crystals formed at the beginning of ascending loop of Henle by heterogeneous nucleation. Concentration of COD crystals in urine was limited and considered equal to concentration of crystals during crystaluria. The free particle and the fixed particle mechanisms were considered. The free particle mechanism assumes formation of a single crystal or agglomerate of crystals blocking the CD by virtue of size. The growth of COD crystals at concrete urinary supersaturation was too slow for a single crystal to attain size with settling velocity faster than the translation flow rate of liquid. Hydrodynamic shear caused aggregation of COD solid particles dispersed in a liquid flowing in the nephron. Number of COD crystals present in urine was not sufficient for formation of fractal agglomerate blocking the Bellini duct. Similarly, a fractal agglomerate of urinary phosphate present in the form of Posner's clusters was not large enough to obstruct the Bellini duct. The opening of the CD could not be obstructed by a single crystal of COD or fractal agglomerate composed of either COD crystals or calcium phosphate clusters, formed

  10. A finite difference model of the iron ore sinter process

    OpenAIRE

    Muller, J.; de Vries, T.L.; Dippenaar, B.A.; Vreugdenburg, J.C.

    2015-01-01

    Iron ore fines are agglomerated to produce sinter, which is an important feed material for blast furnaces worldwide. A model of the iron ore sintering process has been developed with the objective of being representative of the sinter pot test, the standard laboratory process in which the behaviour of specific sinter feed mixtures is evaluated. The model aims to predict sinter quality, including chemical quality and physical strength, as well as key sinter process performance parameters such ...

  11. Quantifying the properties of low-cost powder metallurgy titanium alloys

    International Nuclear Information System (INIS)

    Bolzoni, L.; Ruiz-Navas, E.M.; Gordo, E.

    2017-01-01

    The extensive industrial employment of titanium is hindered by its high production costs where reduction of these costs can be achieved using cheap alloying elements and appropriate alternative processing techniques. In this work the feasibility of the production of low-cost titanium alloys is addressed by adding steel to pure titanium and processing the alloys by powder metallurgy. In particular, a spherical 4140 LCH steel powder commonly used in metal injection moulding is blended with irregular hydride-dehydride Ti. The new low-cost alloys are cold uniaxially pressed and sintered under high vacuum and show comparable properties to other wrought-equivalent and powder metallurgy titanium alloys. Differential thermal analysis and X-ray diffraction analyses confirm that Ti can tolerate the employment of iron as primary alloying element without forming detrimental TiFe-based intermetallic phases. Thus, the newly designed α+β alloys could be used for cheaper non-critical components.

  12. Matrix-reinforcement reactivity in P/M titanium matrix composites

    International Nuclear Information System (INIS)

    Amigo, V.; Romero, F.; Salvador, M. D.; Busquets, D.

    2007-01-01

    The high reactivity of titanium and the facility of the same one to form intermetallics makes difficult obtaining composites with this material and brings the need in any case of covering the principal fibres used as reinforcement. To obtain composites of titanium reinforced with ceramic particles ins proposed in this paper, for this reason it turns out to be fundamental to evaluate the reactivity between the matrix and reinforcement. Both titanium nitride and carbide (TiN and TiC) are investigated as materials of low reactivity whereas titanium silicide (TiSi 2 ) is also studied as materials of major reactivity, already stated by the scientific community. This reactivity will be analysed by means of scanning electron microscopy (SEM) there being obtained distribution maps of the elements that allow to establish the possible influence of the sintering temperature and time. Hereby the matrix-reinforcement interactions are optimized to obtain suitable mechanical properties. (Author) 39 refs

  13. Quantifying the properties of low-cost powder metallurgy titanium alloys

    Energy Technology Data Exchange (ETDEWEB)

    Bolzoni, L., E-mail: bolzoni.leandro@gmail.com [WaiCAM (Waikato Centre for Advanced Materials), The University of Waikato, Private Bag 3105, 3240 Hamilton (New Zealand); Ruiz-Navas, E.M.; Gordo, E. [Department of Materials Science and Engineering, University Carlos III of Madrid, Avda. de la Universidad, 30, 28911 Leganés, Madrid (Spain)

    2017-02-27

    The extensive industrial employment of titanium is hindered by its high production costs where reduction of these costs can be achieved using cheap alloying elements and appropriate alternative processing techniques. In this work the feasibility of the production of low-cost titanium alloys is addressed by adding steel to pure titanium and processing the alloys by powder metallurgy. In particular, a spherical 4140 LCH steel powder commonly used in metal injection moulding is blended with irregular hydride-dehydride Ti. The new low-cost alloys are cold uniaxially pressed and sintered under high vacuum and show comparable properties to other wrought-equivalent and powder metallurgy titanium alloys. Differential thermal analysis and X-ray diffraction analyses confirm that Ti can tolerate the employment of iron as primary alloying element without forming detrimental TiFe-based intermetallic phases. Thus, the newly designed α+β alloys could be used for cheaper non-critical components.

  14. Electrochemical process for the manufacturing of titanium alloy matrix composites

    Directory of Open Access Journals (Sweden)

    V. Soare

    2009-07-01

    Full Text Available The paper presents a new method for precursors’ synthesis of titanium alloys matrix composites through an electrochemical process in molten calcium chloride. The cathode of the cell was made from metallic oxides powders and reinforcement ceramic particles, which were pressed and sintered into disk form and the anode from graphite. The process occurred at 850 °C, in two stages, at 2,7 / 3,2 V: the ionization of the oxygen in oxides and the reduction with calcium formed by electrolysis of calcium oxide fed in the electrolyte. The obtained composite precursors, in a form of metallic sponge, were consolidated by pressing and sintering. Chemical and structural analyses on composites samples were performed.

  15. Liquid phase sintered superconducting cermet

    International Nuclear Information System (INIS)

    Ray, S.P.

    1990-01-01

    This patent describes a method of making a superconducting cermet having superconducting properties with improved bulk density, low porosity and in situ stabilization. It comprises: forming a structure of a superconducting ceramic material having the formula RM 2 Cu 3 O (6.5 + x) wherein R is one or more rare earth elements capable of reacting to form a superconducting ceramic, M is one or more alkaline earth metal elements selected from barium and strontium capable of reacting to form a superconducting ceramic, x is greater than 0 and less than 0.5; and a precious metal compound in solid form selected from the class consisting of oxides, sulfides and halides of silver; and liquid phase sintering the mixture at a temperature wherein the precious metal of the precious metal compound is molten and below the melting point of the ceramic material. The liquid phase sintering is carried out for a time less than 36 hours but sufficient to improve the bulk density of the cermet

  16. 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

  17. 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

  18. Thermally stable sintered porous metal articles

    International Nuclear Information System (INIS)

    Gombach, A.L.; Thellmann, E.L.

    1980-01-01

    A sintered porous metal article is provided which is essentially thermally stable at elevated temperatures. In addition, a method for producing such an article is also provided which method comprises preparing a blend of base metal particles and active dispersoid particles, forming the mixture into an article of the desired shape, and heating the so-formed article at sintering temperatures

  19. 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 ...

  20. 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.

  1. Recrystallization and embrittlement of sintered tungsten

    International Nuclear Information System (INIS)

    Bega, N.D.; Babak, A.V.; Uskov, E.I.

    1982-01-01

    The recrystallization of sintered tungsten with a cellular structure of deformation is studied as related to its embrittlement. It is stated that in case of preliminary recrystallization the sintered tungsten crack resistance does not depend on the testing temperature. The tungsten crack resistance is shown to lower with an increase of the structure tendency to primary recrystallization [ru

  2. 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.

  3. Failure of Titanium Condenser Tubes after 24 Years Power Plant Service

    DEFF Research Database (Denmark)

    Montgomery, Melanie; Enemark, Allan; Hangaard, Anders

    2014-01-01

    The titanium condenser has been in operation for 24 years at Amager unit 3 power plant. In February 2012, the plant was contaminated by seawater due to a failed condenser tube and some tubes were plugged. A month later, the plant tripped again. Small leaks were found again and finally approx. 200...... a plant trip. In addition, small amounts of titanium hydride were revealed to be present in the tubes within the tubesheet indicating that the carbon steel tubesheet was corroding due to ingress of salt water. Although this was not the reason for the failure, it indicated the need for repair of the epoxy...

  4. Two steps sintering alumina doped with niobia

    International Nuclear Information System (INIS)

    Gomes, L.B.; Hatzfeld, J.; Heck, M.; Pokorny, A.; Bergmann, C.P.

    2014-01-01

    In this work, high surface area commercial alumina was doped with niobia and sintered in two steps in order to obtain dense materials with lower processing temperatures. The powders were milled and uniaxially pressed (200 MPa). The first step of sintering took place at 1100°C for 3, 6, 9 and 12 hours, followed by the second step at 1350°C for 3 hours. The relative density, porosity and water absorption of the samples were determined by the Archimedes method. The crystalline phases were analyzed by X-ray Diffraction (XRD) and the morphology of the samples after sintering, evaluated by Scanning Electron Microscopy (SEM). The results indicate that the use of niobia combined with the two steps sintering promotes an increase in the density of the material, even at lower sintering temperatures. (author)

  5. 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)

  6. Chitosan patterning on titanium alloys

    OpenAIRE

    Gilabert Chirivella, Eduardo; Pérez Feito, Ricardo; Ribeiro, Clarisse; Ribeiro, Sylvie; Correia, Daniela; González Martin, María Luisa; Manero Planella, José María; Lanceros Méndez, Senentxu; Gallego Ferrer, Gloria; Gómez Ribelles, José Luis

    2017-01-01

    Titanium and its alloys are widely used in medical implants because of their excellent properties. However, bacterial infection is a frequent cause of titanium-based implant failure and also compromises its osseointegration. In this study, we report a new simple method of providing titanium surfaces with antibacterial properties by alternating antibacterial chitosan domains with titanium domains in the micrometric scale. Surface microgrooves were etched on pure titanium disks at i...

  7. Microstructure and mechanical properties of sintered Ti Binary alloys for dental applications

    Energy Technology Data Exchange (ETDEWEB)

    Yilmaz Atay, H.; Haro Rodriguez, M.; Amigo Mata, A.; Vicente Escuder, V.; Amigo Borras, V.

    2016-07-01

    Biomaterials have shown rapid growth in the field of elderly population demands with the prolongation of human life. One of those biomaterials, titanium, has excellent properties and biocompatibility though it may cause weakening in the structures due to its higher stiffness. In this study, powder metallurgy process was used to produce Ti-Cr, Ti-Mo and Ti-Cu metal alloys to overcome this problem. Metal powders were mixed by mechanical alloying. After pressing and sintering, alloys structures were investigated. Characterizations were carried out by size analyzer, SEM-EDX, optical microscope and three points bending test. (Author)

  8. On the sintering kinetics in UO2

    International Nuclear Information System (INIS)

    Marajofsky, A.

    1998-01-01

    The fabrication process of UO 2 pellets from powders involve pressing and a sintering anneal at high temperature (1650 deg. C to 1750 deg. C) during two or more hours in a hydrogen atmosphere. An alternative method is the oxidative sintering, made at lower temperature (1000 deg. C to 1300 deg. C) in a CO 2 or CO/CO 2 atmosphere. The sintering phenomena consist in the densification of the material by a thermal treatment below the fusion point. For a compact made by pressing a powder, sintering is the process of annulation of the porosity present in the compact or pellet. Several theories describe the sintering phenomena dividing it in three stages, initial, intermediate and final: in all of them the densification is a continuous growing function of time. Nevertheless it has been experimentally reported that a reduction of the density occurs in the third step of the sintering. The phenomena has been called solarization. Solarization has been attributed to the effect of the evolved gases from additives or to the CO 2 atmosphere in oxidative sintering. Thus, it is convenient to distinguish between solarization in oxidative or reducing conditions. Reducing solarization is a consequence of the tendency towards equilibrium of intergranular pores. In oxidative sintering it occurs in the reducing anneal after the sintering and is due to the change in the lattice parameter. This work shows examples of both types of solarization and qualitative interpretation of this phenomena. Both situations show the need of strict control of the sintering and powder production conditions. (author)

  9. Production of titanium tetrachloride

    International Nuclear Information System (INIS)

    Perillo, P.M.; Botbol, O.

    1990-01-01

    This report presents a summary of results from theoperation of a laboratory scale for the production in batches of approximately 100 gs of titanium tetrachloride by chlorination with chloroform and carbon tetrachloride between 340 deg C and 540 deg C. Chlorination agent vapors were passed through a quartz column reacting with titanium oxide powder agglomerated in little spheres. Obtained titanium tetrachloride was condensed in a condenser, taken in a ballon and then purified by fractional distillation. Optimun temperature for chloroform was 400 deg C with 74 % yield and for carbon tetrachloride was 500 deg C with 69 % yield. (Author) [es

  10. A study on stress corrosion cracking of explosive plugged part

    International Nuclear Information System (INIS)

    Kaga, Seiichi; Fujii, Katsuhiro; Yamamoto, Yoshiaki; Sakuma, Koosuke; Hibi, Seiji; Morimoto, Hiroyoshi.

    1986-01-01

    Studies on the stress corrosion cracking of explosive plugged part are conducted. SUS 304 stainless steel is used as testing material. The distribution of residual stress in plug and tube plate after plugging is obtained. The effect of residual stress on the stress corrosion cracking is studied. Residual stress in tube plate near the plug is compressive and stress corrosion cracking dose not occur in the tube plate there, and it occurs on the inner surface of plug because of residual tensile stress in axial direction of the plug. Stress corrosion test in MgCl 2 solution under constant load is conducted. The susceptibility to stress corrosion cracking of the explosive bonded boundary is lower than that of base metal because of greater resistance to plastic deformation. Stress corrosion test in high temperature and high pressure pure water is also conducted by means of static type of autoclave but stress corrosion cracking does not occur under the testing condition used. (author)

  11. Microstructure and mechanical properties of direct metal laser sintered TI-6AL-4V

    Directory of Open Access Journals (Sweden)

    Becker, Thorsten Hermann

    2015-05-01

    Full Text Available Direct metal laser sintering (DMLS is a selective laser melting (SLM manufacturing process that can produce near net shape parts from metallic powders. A range of materials are suitable for SLM; they include various metals such as titanium, steel, aluminium, and cobalt-chrome alloys. This paper forms part of a research drive that aims to evaluate the material performance of the SLM-manufactured metals. It presents DMLS-produced Ti-6Al-4V, a titanium alloy often used in biomedical and aerospace applications. This paper also studies the effect of several heat treatments on the microstructure and mechanical properties of Ti-6Al-4V processed by SLM. It reports the achievable mechanical properties of the alloy, including quasi-static, crack growth behaviour, density and porosity distribution, and post-processing using various heat-treatment conditions.

  12. Sputter deposited titanium disilicide at high substrate temperatures

    Science.gov (United States)

    Tanielian, M.; Blackstone, S.; Lajos, R.

    1984-08-01

    Titanium disilicide films were sputter deposited from a composite TiSi2.1 target on bare silicon wafers both at room temperature and at 600 °C. The room temperature as-deposited films require a 900 °C sintering step to reduce their resistivity. On the other hand, the as-deposited 600 °C films are fully reacted, polycrystalline, have no oxygen contamination, large grain sizes, and are oxidation resistant. Further annealing of these films at 900 °C produces no changes in their crystal structure, composition, resistivity, or grain size.

  13. Mucous plug syndrome. A pulmonary embolism mimic

    International Nuclear Information System (INIS)

    Bray, S.T.; Johnstone, W.H.; Dee, P.M.; Pope, T.L. Jr.; Teates, C.D.; Tegtmeyer, C.J.

    1984-01-01

    Reported are ten instances of major bronchial obstruction by mucous plugs in eight patients during which the clinical features resembled pulmonary embolism. Perfusion lung studies showed significantly diminished perfusion of the involved portions of the lungs. The chest radiographs generally did not, however, reflect the severity of the airway obstruction and in some instances were completely normal. The ventilation studies indicated the extent and severity of the obstruction and matched with the perfusion scans. Pulmonary arteriograms were performed in three patients and gave direct evidence of focally diminished lung perfusion without embolism. The physiologic mechanisms underlying the condition are discussed

  14. Plug ‘n’ Play with DNA

    DEFF Research Database (Denmark)

    Lund, Anne Mathilde; Andreasen, Elisa W.; Korgaard, Jaide V.

    Synthetic biology has evolved dramatically within the past decade, which calls for a revolution of the Standard Assembly method that makes the foundation of BioBricks. We believe that iGEM should be about fast assembly of BioBricks, where any thinkable part, device or existing BioBrick can be com...... be combined for any type of organism within one day. Therefore, we have designed a new BioBrick Kit based on a novel assembly standard; called “Plug 'n' Play with DNA”....

  15. An Insoluble Titanium-Lead Anode for Sulfate Electrolytes

    Energy Technology Data Exchange (ETDEWEB)

    Ferdman, Alla

    2005-05-11

    The project is devoted to the development of novel insoluble anodes for copper electrowinning and electrolytic manganese dioxide (EMD) production. The anodes are made of titanium-lead composite material produced by techniques of powder metallurgy, compaction of titanium powder, sintering and subsequent lead infiltration. The titanium-lead anode combines beneficial electrochemical behavior of a lead anode with high mechanical properties and corrosion resistance of a titanium anode. In the titanium-lead anode, the titanium stabilizes the lead, preventing it from spalling, and the lead sheathes the titanium, protecting it from passivation. Interconnections between manufacturing process, structure, composition and properties of the titanium-lead composite material were investigated. The material containing 20-30 vol.% of lead had optimal combination of mechanical and electrochemical properties. Optimal process parameters to manufacture the anodes were identified. Prototypes having optimized composition and structure were produced for testing in operating conditions of copper electrowinning and EMD production. Bench-scale, mini-pilot scale and pilot scale tests were performed. The test anodes were of both a plate design and a flow-through cylindrical design. The cylindrical anodes were composed of cylinders containing titanium inner rods and fitting over titanium-lead bushings. The cylindrical design allows the electrolyte to flow through the anode, which enhances diffusion of the electrolyte reactants. The cylindrical anodes demonstrate higher mass transport capabilities and increased electrical efficiency compared to the plate anodes. Copper electrowinning represents the primary target market for the titanium-lead anode. A full-size cylindrical anode performance in copper electrowinning conditions was monitored over a year. The test anode to cathode voltage was stable in the 1.8 to 2.0 volt range. Copper cathode morphology was very smooth and uniform. There was no

  16. Thermographic study of the preheating plugs in diesel engines

    OpenAIRE

    Royo Pastor, Rafael; Albertos Arranz, M.A.; CÁRCEL CUBAS, JUAN ANTONIO; Payá Herrero, Jorge

    2012-01-01

    The use of direct injection diesel engines has been widely applied during the past ten years. In such engines, the preheating plugs are a key element which has a significant contribution in the pollutant emissions. In this paper, two different plug designs from Renault are analyzed. The new plug reduces substantially the required electrical consumption. Nevertheless, the pollutant emissions are higher (fundamentally CO and HCs) and hereby a thorough analysis is required to underst...

  17. Characterizations of additive manufactured porous titanium implants.

    Science.gov (United States)

    Basalah, Ahmad; Shanjani, Yaser; Esmaeili, Shahrzad; Toyserkani, Ehsan

    2012-10-01

    This article describes physical, chemical, and mechanical characterizations of porous titanium implants made by an additive manufacturing method to gain insight into the correlation of process parameters and final physical properties of implants used in orthopedics. For the manufacturing chain, the powder metallurgy technology was combined with the additive manufacturing to fabricate the porous structure from the pure tanium powder. A 3D printing machine was employed in this study to produce porous bar samples. A number of physical parameters such as titanium powder size, polyvinyl alcohol (PVA) amount, sintering temperature and time were investigated to control the mechanical properties and porosity of the structures. The produced samples were characterized through porosity and shrinkage measurements, mechanical compression test and scanning electron microscopy (SEM). The results showed a level of porosity in the samples in the range of 31-43%, which is within the range of the porosity of the cancelluous bone and approaches the range of the porosity of the cortical bone. The results of the mechanical test showed that the compressive strength is in the wide range of 56-509 MPa implying the effect of the process parameters on the mechanical strengths. This technique of manufacturing of Ti porous structures demonstrated a low level of shrinkage with the shrinkage percentage ranging from 1.5 to 5%. Copyright © 2012 Wiley Periodicals, Inc.

  18. Pyrolytic carbon coating for cytocompatibility of titanium oxide nanoparticles: a promising candidate for medical applications

    International Nuclear Information System (INIS)

    Behzadi, Shahed; Simchi, Abdolreza; Imani, Mohammad; Yousefi, Mohammad; Galinetto, Pietro; Amiri, Houshang; Stroeve, Pieter; Mahmoudi, Morteza

    2012-01-01

    Nanoparticles for biomedical use must be cytocompatible with the biological environment that they are exposed to. Current research has focused on the surface functionalization of nanoparticles by using proteins, polymers, thiols and other organic compounds. Here we show that inorganic nanoparticles such as titanium oxide can be coated by pyrolytic carbon (PyC) and that the coating has cytocompatible properties. Pyrolization and condensation of methane formed a thin layer of pyrolytic carbon on the titanium oxide core. The formation of the PyC shell retards coalescence and sintering of the ceramic phase. Our MTT assay shows that the PyC-coated particles are cytocompatible at employed doses. (paper)

  19. Synchrotron X-ray CT characterization of titanium parts fabricated by additive manufacturing. Part I. Morphology.

    Science.gov (United States)

    Scarlett, Nicola Vivienne Yorke; Tyson, Peter; Fraser, Darren; Mayo, Sheridan; Maksimenko, Anton

    2016-07-01

    Synchrotron X-ray tomography has been applied to the study of titanium parts fabricated by additive manufacturing (AM). The AM method employed here was the Arcam EBM(®) (electron beam melting) process which uses powdered titanium alloy, Ti64 (Ti alloy with approximately 6%Al and 4%V), as the feed and an electron beam for the sintering/welding. The experiment was conducted on the Imaging and Medical Beamline of the Australian Synchrotron. Samples were chosen to examine the effect of build direction and complexity of design on the surface morphology and final dimensions of the piece.

  20. Knowledge-Based System to Support Plug Load Management

    Data.gov (United States)

    National Aeronautics and Space Administration — Electrical plug loads comprise an increasingly larger share of building energy consumption as improvements have been made to Heating, Ventilation, and Air...

  1. Mechanical Properties of Plug Welds after Micro-Jet Cooling

    OpenAIRE

    Hadryś D.

    2016-01-01

    New technology of micro-jet welding could be regarded as a new way to improve mechanical properties of plug welds. The main purpose of that paper was analyzing of mechanical properties of plug welds made by MIG welding method with micro-jet cooling. The main way for it was comparison of plug welds made by MIG welding method with micro-jet cooling and plug welds made by ordinary MIG welding method. It is interesting for steel because higher amount of acicular ferrite (AF) in weld metal deposit...

  2. An Overview of the HomePlug AV2 Technology

    OpenAIRE

    Yonge, Larry; Abad, Jose; Afkhamie, Kaywan; Guerrieri, Lorenzo; Katar, Srinivas; Lioe, Hidayat; Pagani, Pascal; Riva, Raffaele; Schneider, Daniel M.; Schwager, Andreas

    2013-01-01

    HomePlug AV2 is the solution identified by the HomePlug Alliance to achieve the improved data rate performance required by the new generation of multimedia applications without the need to install extra wires. Developed by industry-leading participants in the HomePlug AV Technical Working Group, the HomePlug AV2 technology provides Gigabit-class connection speeds over the existing AC wires within home. It is designed to meet the market demands for the full set of future in-home networking co...

  3. Electroplating on titanium alloy

    Science.gov (United States)

    Lowery, J. R.

    1971-01-01

    Activation process forms adherent electrodeposits of copper, nickel, and chromium on titanium alloy. Good adhesion of electroplated deposits is obtained by using acetic-hydrofluoric acid anodic activation process.

  4. Melting and Sintering of Ashes

    DEFF Research Database (Denmark)

    Hansen, Lone Aslaug

    1997-01-01

    -1300°C, and a trend of higher fusion temperatures with increasing contents of Al-silicates and quartz was found.c) Fly ashes, bottom ashes and deposits from coal/straw co-firing were all found to consist mainly of metal-alumina and alumina-silicates. These ashes all melt in the temperature range 1000......The thesis contains an experimental study of the fusion and sintering of ashes collected during straw and coal/straw co-firing.A laboratory technique for quantitative determination of ash fusion has been developed based on Simultaneous Thermal Analysis (STA). By means of this method the fraction......, 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...

  5. 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

  6. Titanium oxide fever

    International Nuclear Information System (INIS)

    De Jonge, D.; Visser, J.

    2012-01-01

    One measure to improve air quality is to apply photo-catalytic substances that capture NOx onto the road surface or onto baffle boards alongside the roads. The effect of titanium oxide containing clinkers with coating was discussed in the report 'Demonstration project of air-purifying pavement in Hengelo, The Netherlands' that was published in May 2011. This article examines the way in which the effectiveness of this study was determined. Can titanium oxide containing clinkers and coatings indeed capture NOx?. [nl

  7. Machining of titanium alloys

    CERN Document Server

    2014-01-01

    This book presents a collection of examples illustrating the resent research advances in the machining of titanium alloys. These materials have excellent strength and fracture toughness as well as low density and good corrosion resistance; however, machinability is still poor due to their low thermal conductivity and high chemical reactivity with cutting tool materials. This book presents solutions to enhance machinability in titanium-based alloys and serves as a useful reference to professionals and researchers in aerospace, automotive and biomedical fields.

  8. 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

  9. Ford C-Max plug-in hybrid; Ford C-Max mit Plug-in-Hybridtechnik

    Energy Technology Data Exchange (ETDEWEB)

    Schamel, Andreas; D' Annunzio, Julie; Iorio, Rob [Ford Motor Company, Dearborn, MI (United States); Schmitz, Peter [Ford-Forschungszentrum Aachen GmbH, Aachen (Germany)

    2013-03-01

    Ford provides consumers a broad choice of electrified vehicles globally, including full hybrids, plug-in hybrids and all-electric vehicles. The all-new 2013 model year C-Max Energi Plug-in Hybrid utilises the third generation of Ford hybrid technology. This article discusses the hybrid powersplit architecture and components, as well as the charging capability and human-machine interfaces, used in the C-Max Energi Plug-In Hybrid. (orig.)

  10. Deep Space Habitat Wireless Smart Plug

    Science.gov (United States)

    Morgan, Joseph A.; Porter, Jay; Rojdev, Kristina; Carrejo, Daniel B.; Colozza, Anthony J.

    2014-01-01

    NASA has been interested in technology development for deep space exploration, and one avenue of developing these technologies is via the eXploration Habitat (X-Hab) Academic Innovation Challenge. In 2013, NASA's Deep Space Habitat (DSH) project was in need of sensors that could monitor the power consumption of various devices in the habitat with added capability to control the power to these devices for load shedding in emergency situations. Texas A&M University's Electronic Systems Engineering Technology Program (ESET) in conjunction with their Mobile Integrated Solutions Laboratory (MISL) accepted this challenge, and over the course of 2013, several undergraduate students in a Capstone design course developed five wireless DC Smart Plugs for NASA. The wireless DC Smart Plugs developed by Texas A&M in conjunction with NASA's Deep Space Habitat team is a first step in developing wireless instrumentation for future flight hardware. This paper will further discuss the X-Hab challenge and requirements set out by NASA, the detailed design and testing performed by Texas A&M, challenges faced by the team and lessons learned, and potential future work on this design.

  11. Sintering and microstructure of ice: a review

    International Nuclear Information System (INIS)

    Blackford, Jane R

    2007-01-01

    Sintering of ice is driven by the thermodynamic requirement to decrease surface energy. The structural morphology of ice in nature has many forms-from snowflakes to glaciers. These forms and their evolution depend critically on the balance between the thermodynamic and kinetic factors involved. Ice is a crystalline material so scientific understanding and approaches from more conventional materials can be applied to ice. The early models of solid state ice sintering are based on power law models originally developed in metallurgy. For pressure sintering of ice, these are based on work on hot isostatic pressing of metals and ceramics. Recent advances in recognizing the grain boundary groove geometry between sintering ice particles require models that use new approaches in materials science. The newer models of sintering in materials science are beginning to incorporate more realistic processing conditions and microstructural complexity, and so there is much to be gained from applying these to ice in the future. The vapour pressure of ice is high, which causes it to sublime readily. The main mechanism for isothermal sintering of ice particles is by vapour diffusion; however other transport mechanisms certainly contribute. Plastic deformation with power law creep combined with recrystallization become important mechanisms in sintering with external pressure. Modern experimental techniques, low temperature scanning electron microscopy and x-ray tomography, are providing new insights into the evolution of microstructures in ice. Sintering in the presence of a small volume fraction of the liquid phase causes much higher bond growth rates. This may be important in natural snow which contains impurities that form a liquid phase. Knowledge of ice microstructure and sintering is beneficial in understanding mechanical behaviour in ice friction and the stability of snow slopes prone to avalanches. (topical review)

  12. Design of sintering-stable heterogeneous catalysts

    DEFF Research Database (Denmark)

    Gallas-Hulin, Agata

    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...

  13. 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

  14. Effect of rigid inclusions on sintering

    International Nuclear Information System (INIS)

    Rahaman, M.N.; De Jonghe, L.C.

    1988-01-01

    The predictions of recent theoretical studies on the effect of inert, rigid inclusions on the sintering of ceramic powder matrices are examined and compared with experimental data. The densification of glass matrix composites with inclusion volume fractions of ≤0.15 can be adequately explained by Scherer's theory for viscous sintering with rigid inclusions. Inclusions cause a vast reduction in the densification rates of polycrystalline matrix composites even at low inclusion volume fractions. Models put forward to explain the sintering of polycrystalline matrix composites are discussed

  15. 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

  16. 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 ...

  17. Titanium by design: TRIP titanium alloy

    Science.gov (United States)

    Tran, Jamie

    Motivated by the prospect of lower cost Ti production processes, new directions in Ti alloy design were explored for naval and automotive applications. Building on the experience of the Steel Research Group at Northwestern University, an analogous design process was taken with titanium. As a new project, essential kinetic databases and models were developed for the design process and used to create a prototype design. Diffusion kinetic models were developed to predict the change in phase compositions and microstructure during heat treatment. Combining a mobility database created in this research with a licensed thermodynamic database, ThermoCalc and DICTRA software was used to model kinetic compositional changes in titanium alloys. Experimental diffusion couples were created and compared to DICTRA simulations to refine mobility parameters in the titanium mobility database. The software and database were able to predict homogenization times and the beta→alpha plate thickening kinetics during cooling in the near-alpha Ti5111 alloy. The results of these models were compared to LEAP microanalysis and found to be in reasonable agreement. Powder metallurgy was explored using SPS at GM R&D to reduce the cost of titanium alloys. Fully dense Ti5111 alloys were produced and achieved similar microstructures to wrought Ti5111. High levels of oxygen in these alloys increased the strength while reducing the ductility. Preliminary Ti5111+Y alloys were created, where yttrium additions successfully gettered excess oxygen to create oxides. However, undesirable large oxides formed, indicating more research is needed into the homogeneous distribution of the yttrium powder to create finer oxides. Principles established in steels were used to optimize the beta phase transformation stability for martensite transformation toughening in titanium alloys. The Olson-Cohen kinetic model is calibrated to shear strains in titanium. A frictional work database is established for common alloying

  18. Biomass plug development and propagation in porous media.

    Science.gov (United States)

    Stewart, T L; Fogler, H S

    2001-02-05

    Exopolymer-producing bacteria can be used to modify soil profiles for enhanced oil recovery or bioremediation. Understanding the mechanisms associated with biomass plug development and propagation is needed for successful application of this technology. These mechanisms were determined from packed-bed and micromodel experiments that simulate plugging in porous media. Leuconostoc mesenteroides was used, because production of dextran, a water-insoluble exopolymer, can be controlled by using different carbon sources. As dextran was produced, the pressure drop across the porous media increased and began to oscillate. Three pressure phases were identified under exopolymer-producing conditions: the exopolymer-induction phase, the plugging phase, and the plug-propagation phase. The exopolymer-induction phase extended from the time that exopolymer-producing conditions were induced until there was a measurable increase in pressure drop across the porous media. The plugging phase extended from the first increase in pressure drop until a maximum pressure drop was reached. Changes in pressure drop in these two phases were directly related to biomass distribution. Specifically, flow channels within the porous media filled with biomass creating a plugged region where convective flow occurred only in water channels within the biofilm. These water channels were more restrictive to flow causing the pressure drop to increase. At a maximum pressure drop across the porous media, the biomass yielded much like a Bingham plastic, and a flow channel was formed. This behavior marked the onset of the plug-propagation phase which was characterized by sequential development and breakthrough of biomass plugs. This development and breakthrough propagated the biomass plug in the direction of nutrient flow. The dominant mechanism associated with all three phases of plugging in porous media was exopolymer production; yield stress is an additional mechanism in the plug-propagation phase. Copyright

  19. Developing quality standards for physical properties of mineral wool plugs

    NARCIS (Netherlands)

    Blok, C.; Berg, van den C.C.; Winkel, van A.

    2014-01-01

    The KIWA certification guidelines for mineral wool products contain standards for slabs and blocks. Propagators would like to introduce quality standards for mineral wool plugs as well. Main concerns were effects of too dense plugs on plant growth, and handling problems with too fluffy or broken

  20. Plug and Play Process Control of a District Heating System

    DEFF Research Database (Denmark)

    Trangbaek, Klaus; Knudsen, Torben; Skovmose Kallesøe, Carsten

    2009-01-01

    The main idea of plug and play process control is to initialise and reconfigure control systems automatically. In this paper these ideas are applied to a scaled laboratory model of a district heating pressure control system.  First of all this serves as a concrete example of plug and play control...

  1. Capillarity Induced Negative Pressure of Water Plugs in Nanochannels

    NARCIS (Netherlands)

    Tas, Niels Roelof; Mela, P.; Kramer, Tobias; Berenschot, Johan W.; van den Berg, Albert

    2003-01-01

    We have found evidence that water plugs in hydrophilic nanochannels can be at significant negative pressure due to tensile capillary forces. The negative pressure of water plugs in nanochannels induces bending of the thin channel capping layer, which results in a visible curvature of the liquid

  2. Plug-in hybrid electric vehicles in dynamical energy markets

    NARCIS (Netherlands)

    Kessels, J.T.B.A.; Bosch, P.P.J. van den

    2008-01-01

    The plug-in hybrid electric vehicle allows vehicle propulsion from multiple internal power sources. Electric energy from the grid can be utilized by means of the plug-in connection. An on-line energy management (EM) strategy is proposed to minimize the costs for taking energy from each power source.

  3. Analyzing the Risk of Well Plug Failure after Abandonment

    International Nuclear Information System (INIS)

    Mainguy, M.; Longuemare, P.; Audibert, A.; Lecolier, E.

    2007-01-01

    All oil and gas wells will have to be plugged and abandoned at some time. The plugging and abandonment procedure must provide an effective isolation of the well fluids all along the well to reduce environmental risks of contamination and prevent from costly remedial jobs. Previous works have analyzed the plug behavior when submitted to local pressure or thermal changes but no work has looked to the effects of external pressure, thermal and stress changes resulting from a global equilibrium restoration in a hydrocarbon reservoir once production has stopped. This work estimates those changes after abandonment on a reservoir field case using a reservoir simulator in conjunction with a geomechanical simulator. Such simulations provide the pressure and thermal changes and the maximum effective stress changes in the reservoir cap rock where critical plugs are put in place for isolating the production intervals. These changes are used as loads in a well bore stress model that explicitly models an injector well and predict stress rearrangements in the plug after abandonment. Results obtained with the well bore stress model for a conventional class G cement plug show that the main risk of failure is tensile failure because of the low tensile strength of the cement. Actually, soft sealing materials or initially pre-stressed plug appears to be more adapted to the downhole conditions changes that may occurs after well plugging and abandonment. (authors)

  4. Dual Spark Plugs For Stratified-Charge Rotary Engine

    Science.gov (United States)

    Abraham, John; Bracco, Frediano V.

    1996-01-01

    Fuel efficiency of stratified-charge, rotary, internal-combustion engine increased by improved design featuring dual spark plugs. Second spark plug ignites fuel on upstream side of main fuel injector; enabling faster burning and more nearly complete utilization of fuel.

  5. California Statewide Plug-In Electric Vehicle Infrastructure Assessment

    Energy Technology Data Exchange (ETDEWEB)

    Melaina, Marc; Helwig, Michael

    2014-05-01

    The California Statewide Plug-In Electric Vehicle Infrastructure Assessment conveys to interested parties the Energy Commission’s conclusions, recommendations, and intentions with respect to plug-in electric vehicle (PEV) infrastructure development. There are several relatively low-risk and high-priority electric vehicle supply equipment (EVSE) deployment options that will encourage PEV sales and

  6. National Plug-In Electric Vehicle Infrastructure Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Wood, Eric [National Renewable Energy Lab. (NREL), Golden, CO (United States); Rames, Clement [National Renewable Energy Lab. (NREL), Golden, CO (United States); Muratori, Matteo [National Renewable Energy Lab. (NREL), Golden, CO (United States)

    2017-09-15

    This report addresses the fundamental question of how much plug-in electric vehicle (PEV) charging infrastructure—also known as electric vehicle supply equipment (EVSE)—is needed in the United States to support both plug-in hybrid electric vehicles (PHEVs) and battery electric vehicles (BEVs).

  7. Eddy current inspection of steam generator tubing plugs

    International Nuclear Information System (INIS)

    Cullen, W.K.

    1990-01-01

    In response to the issues raised regarding the integrity of nuclear steam generator tubing plugs manufactured from certain heats of Inconel 600, Westinghouse engineers have developed, qualified and implemented an eddy current inspection system for the in-place assessment of these plugs. The heart of the system is a robotic and effector which delivers an eddy current sensor through the reduced diameter of the plug expander and actuates the coil to physical contact with the expanded inside bore of the plug. Once deployed, the eddy current sensor is rotated along a helical path to produce a detailed scan of the plug surface above the final position of the expander. This testing produces an isometric display of degradation due to primary water stress corrosion cracking, on the inside surface of the plug. To date, successful inspections have been conducted at two nuclear units with two different robotic delivery systems. While designed specifically for mechanical plugs with a bottle bore cavity, the inspection system can also be used for expanded straight bore plugs. Details of the inspection system along with a discussion of qualification activities and actual field results are presented in this paper

  8. Two-dimensional simulation of sintering process

    International Nuclear Information System (INIS)

    Vasconcelos, Vanderley de; Pinto, Lucio Carlos Martins; Vasconcelos, Wander L.

    1996-01-01

    The results of two-dimensional simulations are directly applied to systems in which one of the dimensions is much smaller than the others, and to sections of three dimensional models. Moreover, these simulations are the first step of the analysis of more complex three-dimensional systems. In this work, two basic features of the sintering process are studied: the types of particle size distributions related to the powder production processes and the evolution of geometric parameters of the resultant microstructures during the solid-state sintering. Random packing of equal spheres is considered in the sintering simulation. The packing algorithm does not take into account the interactive forces between the particles. The used sintering algorithm causes the densification of the particle set. (author)

  9. SINTERED REFRACTORY TUNGSTEN ALLOYS. Gesinterte hochschmelzende wolframlegierungen

    Energy Technology Data Exchange (ETDEWEB)

    Kieffer, R.; Sedlatschek, K.; Braun, H.

    1971-12-15

    Dependence of the melting point of the refractory metals on their positions in the periodic system - alloys of tungsten with other refractory metals - sintering of the alloys - processing of the alloys - technological properties.

  10. 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

  11. Pressureless sintering of whisker-toughened ceramic composites

    Science.gov (United States)

    Tiegs, T.N.

    1993-05-04

    A pressureless sintering method is disclosed for use in the production of whisker-toughened ceramic composites wherein the sintered density of composites containing up to about 20 vol. % SiC whiskers is improved by reducing the average aspect ratio of the whiskers to from about 10 to about 20. Sintering aids further improve the density, permitting the production of composites containing 20 vol. % SiC with sintered densities of 94% or better of theoretical density by a pressureless sintering method.

  12. Sintering of Fine Particles in Suspension Plasma Sprayed Coatings

    Directory of Open Access Journals (Sweden)

    Leszek Latka

    2010-07-01

    Full Text Available Suspension plasma spraying is a process that enables the production of finely grained nanometric or submicrometric coatings. The suspensions are formulated with the use of fine powder particles in water or alcohol with some additives. Subsequently, the suspension is injected into plasma jet and the liquid additives evaporate. The remaining fine solids are molten and subsequently agglomerate or remain solid, depending on their trajectory in the plasma jet. The coating’s microstructure results from these two groups of particles arriving on a substrate or previously deposited coating. Previous experimental studies carried out for plasma sprayed titanium oxide and hydroxyapatite coatings enabled us to observe either a finely grained microstructure or, when a different suspension injection mode was used, to distinguish two zones in the microstructure. These two zones correspond to the dense zone formed from well molten particles, and the agglomerated zone formed from fine solid particles that arrive on the substrate in a solid state. The present paper focuses on the experimental and theoretical analysis of the formation process of the agglomerated zone. The experimental section establishes the heat flux supplied to the coating during deposition. In order to achieve this, calorimetric measurements were made by applying experimental conditions simulating the real coatings’ growth. The heat flux was measured to be in the range from 0.08 to 0.5 MW/m2,depending on the experimental conditions. The theoretical section analyzes the sintering during the coating’s growth, which concerns the fine particles arriving on the substrate in the solid state. The models of volume, grain boundary and surface diffusion were analyzed and adapted to the size and chemistry of the grains, temperature and time scales corresponding to the suspension plasma spraying conditions. The model of surface diffusion was found to best describe the sintering during suspension

  13. Mechanical characteristics of microwave sintered silicon carbide

    Indian Academy of Sciences (India)

    Unknown

    sintered process, SiC grain gets oxidized producing SiO2 (∼ 32 wt%) and deteriorates the quality of the product substantially. Partially sintered .... product, could be due to oxidation of SiC, e.g. 50% weight gain of a green SiC sample ... because, the charging current is 90° advanced in phase, ideally, with respect to the ...

  14. Techniques for ceramic sintering using microwave energy

    International Nuclear Information System (INIS)

    Kimrey, H.D.; Janney, M.A.; Becher, P.F.

    1987-01-01

    The use of microwave energy for ceramic sintering offers exciting new possibilities for materials processing. Based on experience gathered in microwave processing associated with the heating of fusion plasmas, we have developed hardware and methods for uniformly heating ceramic parts of large volume and irregular shape to temperatures in excess of 1600 0 C, in vacuum or pressurized atmosphere. Microwave processing at 28 GHz yields enhanced densification rates with a corresponding reduction in sintering temperatures. 6 refs

  15. Proceedings of the workshop on borehole and shaft plugging

    International Nuclear Information System (INIS)

    1980-01-01

    Geologic disposal of radioactive waste relies on the capability of many geological formations to provide long-term containment of the waste. The disposal operations could significantly modify the original conditions. In addition to the underground excavations and the thermal input of the waste their is the problem of boreholes and shafts that constitute a potential by-pass of the geological barriers. It is therefore essential to develop techniques and procedures for effective plugging of all penetrations connecting the disposal zone with the surface or with water bearing layers. It will be necessary to produce plugs which effectively restore the original characteristics of the isolating formations. In addition these plugs must be chemically stable in the existing geochemical environment in order to remain effective for very long periods of time and the plugs of disposal holes can be exposed to high temperatures and radiation doses. All countries with geologic disposal programmes will have to face the problem of borehole and shapt plugging

  16. Development of sealing plug for sweep gas line

    International Nuclear Information System (INIS)

    Kikuchi, Taiji; Yamada, Hirokazu; Saitoh, Takashi; Nakamichi, Masaru; Tsuchiya, Kunihiko; Kawamura, Hiroshi

    2004-03-01

    On the irradiation capsule for neutron irradiation test of the tritium breeder, the sealing plug is necessary to prevent a leak of tritium gas when the tritium breeder is picked up from the irradiation capsule after irradiation test. However, the general valve and plug cannot apply to sealing of the sweep gas line because of the following factors, the neutron irradiation effect, limited space in the irradiation capsule, high sealing efficiency, simple method and operation for control. Therefore, the sealing plug for sweep gas line has to be developed. This paper reports the development of the sealing plug for sweep gas line and the operating procedure of the sealing plug in the irradiation capsule. (author)

  17. A Genre Classification Plug-in for Data Collection

    DEFF Research Database (Denmark)

    Lehn-Schiøler, Tue; Arenas-García, Jerónimo; Petersen, Kaare Brandt

    2006-01-01

    This demonstration illustrates how the methods developed in the MIR community can be used to provide real-time feedback to music users. By creating a genre classifier plug-in for a popular media player we present users with relevant information as they play their songs. The plug-in can furthermor...... be used as a data collection platform. After informed consent from a selected set of users the plug-in will report on music consumption behavior back to a central server.......This demonstration illustrates how the methods developed in the MIR community can be used to provide real-time feedback to music users. By creating a genre classifier plug-in for a popular media player we present users with relevant information as they play their songs. The plug-in can furthermore...

  18. Borehole plugging by compaction process. Final report

    International Nuclear Information System (INIS)

    Fernandez, R.; MacGowan, C.; Nolan, E.; Morey, R.; Palty, A.

    1976-08-01

    The requirements of an overall program to preserve the integrity of a repository formation are documented. The repository is intended to be in stable earth stratum used as a safe and permanent storage area for nuclear waste material. These wastes represent an environmental hazard for a period of up to 200,000 years. An engineering analysis, a reliability and quality-assurance program, and a development program for borehole plugging by compaction process, using natural earthen materials, are presented. Part 1 provides the engineering analysis of downhole compaction methods and related instrumentation along with a recommended development plan from concept through a pilot in-situ experiment. Part 2 provides a reliability and quality-assurance program from laboratory testing of materials through an in-situ experiment

  19. Mitigation of Syngas Cooler Plugging and Fouling

    Energy Technology Data Exchange (ETDEWEB)

    Bockelie, Michael J. [Reaction Engineering International, Salt Lake City, UT (United States)

    2015-06-29

    This Final Report summarizes research performed to develop a technology to mitigate the plugging and fouling that occurs in the syngas cooler used in many Integrated Gasification Combined Cycle (IGCC) plants. The syngas cooler is a firetube heat exchanger located downstream of the gasifier. It offers high thermal efficiency, but its’ reliability has generally been lower than other process equipment in the gasification island. The buildup of ash deposits that form on the fireside surfaces in the syngas cooler (i.e., fouling) lead to reduced equipment life and increased maintenance costs. Our approach to address this problem is that fouling of the syngas cooler cannot be eliminated, but it can be better managed. The research program was funded by DOE using two budget periods: Budget Period 1 (BP1) and Budget Period 2 (BP2). The project used a combination of laboratory scale experiments, analysis of syngas cooler deposits, modeling and guidance from industry to develop a better understanding of fouling mechanisms and to develop and evaluate strategies to mitigate syngas cooler fouling and thereby improve syngas cooler performance. The work effort in BP 1 and BP 2 focused on developing a better understanding of the mechanisms that lead to syngas cooler plugging and fouling and investigating promising concepts to mitigate syngas cooler plugging and fouling. The work effort focused on the following: • analysis of syngas cooler deposits and fuels provided by an IGCC plant collaborating with this project; • performing Jet cleaning tests in the University of Utah Laminar Entrained Flow Reactor to determine the bond strength between an ash deposit to a metal plate, as well as implementing planned equipment modifications to the University of Utah Laminar Entrained Flow Reactor and the one ton per day, pressurized Pilot Scale Gasifier; • performing Computational Fluid Dynamic modeling of industrially relevant syngas cooler configurations to develop a better

  20. Plugging criteria for WWER SG tubes

    Energy Technology Data Exchange (ETDEWEB)

    Papp, L.; Wilam, M. [Vitkovice NPP Services (Switzerland); Herman, M. [Vuje, Trnava (Slovakia)

    1997-12-31

    At operated Czech and Slovak nuclear power plants the 80 % criteria for crack or other bulk defect depth is used for steam generator heat exchanging tubes plugging. This criteria was accepted as the recommendation of designer of WWER steam generators. Verification of this criteria was the objective of experimental program performed by Vitkovice, J.S.C., UJV Rez, J.S.C. and Vuje Trnava, J.S.C .. Within this program the following factors were studied: (1) Influence of secondary water chemistry on defects initiation and propagation, (2) Statistical evaluation of corrosion defects progression at operated SG, and (3) Determination of critical pressure for tube rupture as a function of eddy current indications. In this presentation items (2) and (3) are considered.

  1. Welding nuclear reactor fuel rod end plugs

    International Nuclear Information System (INIS)

    Yeo, D.

    1984-01-01

    Apparatus for applying a vacuum to a nuclear fuel rod cladding tube's interior through its open end while girth welding an inserted end plug to its other end. An airtight housing has an orifice with a seal which can hermetically engage the tube's open end. A vacuum hose has one end connected to the housing and the other end connected to a vacuum pump. A mechanized device which moves the housing to engage or disengage its seal with the tube's open end includes at least one arm having one end attached to the housing and the other end pivotally attached to a movable table; an arm rotating device to coaxially align the housing's orifice with the welding-positioned tube; and a table moving device to engage the seal of the coaxially aligned orifice with the tube's open end. (author)

  2. Experimental plug and play quantum coin flipping

    Science.gov (United States)

    Pappa, Anna; Jouguet, Paul; Lawson, Thomas; Chailloux, André; Legré, Matthieu; Trinkler, Patrick; Kerenidis, Iordanis; Diamanti, Eleni

    2014-04-01

    Performing complex cryptographic tasks will be an essential element in future quantum communication networks. These tasks are based on a handful of fundamental primitives, such as coin flipping, where two distrustful parties wish to agree on a randomly generated bit. Although it is known that quantum versions of these primitives can offer information-theoretic security advantages with respect to classical protocols, a demonstration of such an advantage in a practical communication scenario has remained elusive. Here we experimentally implement a quantum coin flipping protocol that performs strictly better than classically possible over a distance suitable for communication over metropolitan area optical networks. The implementation is based on a practical plug and play system, developed by significantly enhancing a commercial quantum key distribution device. Moreover, we provide combined quantum coin flipping protocols that are almost perfectly secure against bounded adversaries. Our results offer a useful toolbox for future secure quantum communications.

  3. Plugging criteria for WWER SG tubes

    Energy Technology Data Exchange (ETDEWEB)

    Papp, L; Wilam, M [Vitkovice NPP Services (Switzerland); Herman, M [Vuje, Trnava (Slovakia)

    1998-12-31

    At operated Czech and Slovak nuclear power plants the 80 % criteria for crack or other bulk defect depth is used for steam generator heat exchanging tubes plugging. This criteria was accepted as the recommendation of designer of WWER steam generators. Verification of this criteria was the objective of experimental program performed by Vitkovice, J.S.C., UJV Rez, J.S.C. and Vuje Trnava, J.S.C .. Within this program the following factors were studied: (1) Influence of secondary water chemistry on defects initiation and propagation, (2) Statistical evaluation of corrosion defects progression at operated SG, and (3) Determination of critical pressure for tube rupture as a function of eddy current indications. In this presentation items (2) and (3) are considered.

  4. Plugging of drinking water flow into horizontal high diameter pipeline with artificial ice plug

    International Nuclear Information System (INIS)

    Gyongyosi, T.; Valeca, S.; Panaitescu, V. N.; Prisecaru, I.

    2013-01-01

    Local isolation of a pipeline section, placed horizontally into a loop of drinking water supply network, can be made with an ice plug resulting after controlled process inside of pipeline without stopping the consumer supply. The technique is applying in order to perform repairs or items replacement, without closing the drinking water supply network at the same time decreasing the fluid loss resulted after discharge of the affected loop. In facts, the technique is simple one and assumes to apply a special device sized for each case using a freezing liquid agent injected continuously. The paper contains a constructive description of the experimental technological facilities and of the experimental model for ice plugging device used. The test, the first results get and some conclusion are following. The paper is dedicated to the specialists working in the research and technological engineering. (authors)

  5. Strategies for Controlling Plug Loads. A Tool for Reducing Plug Loads in Commercial Buildings

    Energy Technology Data Exchange (ETDEWEB)

    Torcellini, Paul [National Renewable Energy Lab. (NREL), Golden, CO (United States); Bonnema, Eric [National Renewable Energy Lab. (NREL), Golden, CO (United States); Sheppy, Michael [National Renewable Energy Lab. (NREL), Golden, CO (United States); Pless, Shanti [National Renewable Energy Lab. (NREL), Golden, CO (United States)

    2015-09-01

    Plug loads are often not considered as part of the energy savings measures in Commercial Buildings; however, they can account for up to 50% of the energy used in the building. These loads are numerous and often scattered throughout a building. Some of these loads are purchased by the owner and some designed into the building or the tenant finishes for a space. This document provides a strategy and a tool for minimizing these loads.

  6. Cyclic variation of heat flux on spark plug; Tenka plug bu no netsuryusoku hendo no sokutei

    Energy Technology Data Exchange (ETDEWEB)

    Ishii, K.; Sasaki, T.; Urata, Y. [Honda Motor Co. Ltd., Tokyo (Japan); Kagawa, J.; Matsutani, W. [NGK Spark Plug Co. Ltd., Nagoya (Japan)

    1998-02-25

    This paper examines the relationship between the magnitude of the heat flux to the spark plug ground electrode, averaged over an 80` crank angle (CA) of early compression stroke, and the initial burning rate, defined as the CA at which 5% of mass is burned. The heat flux was measured by a thin-film thermocouple with the hot junction on the surface of ground electrode. The results demonstrate that faster initial burning rate correlated well with increasing heat flux from the spark plug to the mixture. The difference in the magnitude and direction of the heat flux is associated with the amount of residual gas concentration and thus the results show the effect of residual gas concentration. The cycle-averaged heat flux from the hot junction is 0.367 MW/m{sup 2}, corresponding to a total heat flow of 20 W from the total surface area of ground electrode. This value is about an order of magnitude larger than that previously reported in the literature for locations away from the spark plug, e. g. at the cylinder wall. 11 refs., 9 figs., 1 tab.

  7. Spark Plasma Sintering of Ultracapacitors

    Energy Technology Data Exchange (ETDEWEB)

    Hill, Curtis W. [CK Technologies, Camirillo, CA (United States); Boatner, Lynn A. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Tucker, Dennis [NASA Johnson Space Center, Houston, TX (United States); Kolopus, James A. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Cheng, Zhongyang [Auburn Univ., AL (United States)

    2016-01-01

    A solid-state ultracapacitor module to replace standard electrochemical batteries would achieve major performance gains and mass/volume reduction. This report summarizes a project to evaluate an alternative sintering process to produce a solid-state ultracapacitor to overcome the limitations of both the electrochemical batteries presently in use on spacecraft and of currently available electrochemical ultracapacitors. It will provide a robust energy storage device with higher reliability, wider working temperature range, longer lifetime, and less weight and volume than electrochemical batteries. As modern electronics decrease in size, more efficient and robust remote power is needed. Current state-of-the-art rechargeable batteries cannot be rapidly charged, contain harmful chemicals, and suffer from early wear-out mechanisms. Solid-state ultracapacitors are recyclable energy storage devices that offer the promise of higher power and a greater number of charge/discharge cycles than current rechargeable batteries. In addition, the theoretical energy density when compared to current electrochemical batteries indicates that a significant weight savings is possible. This is a project to develop a very high density solid-state ultracapacitor with giant permittivity and acceptable dielectric loss to overcome the energy-density barrier such that it will be a suitable replacement for batteries.

  8. 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.

  9. Titanium metal: extraction to application

    Energy Technology Data Exchange (ETDEWEB)

    Gambogi, Joseph (USGS, Reston, VA); Gerdemann, Stephen J.

    2002-09-01

    In 1998, approximately 57,000 tons of titanium metal was consumed in the form of mill products (1). Only about 5% of the 4 million tons of titanium minerals consumed each year is used to produce titanium metal, with the remainder primarily used to produce titanium dioxide pigment. Titanium metal production is primarily based on the direct chlorination of rutile to produce titanium tetrachloride, which is then reduced to metal using the Kroll magnesium reduction process. The use of titanium is tied to its high strength-to-weight ratio and corrosion resistance. Aerospace is the largest application for titanium. In this paper, we discuss all aspects of the titanium industry from ore deposits through extraction to present and future applications. The methods of both primary (mining of ore, extraction, and purification) and secondary (forming and machining) operations will be analyzed. The chemical and physical properties of titanium metal will be briefly examined. Present and future applications for titanium will be discussed. Finally, the economics of titanium metal production also are analyzed as well as the advantages and disadvantages of various alternative extraction methods.

  10. Industrial experience with titanium

    International Nuclear Information System (INIS)

    Ikeda, B.M.; Shoesmith, D.W.

    1997-09-01

    Titanium is a reference material for the construction of waste containers in the Canadian Nuclear Fuel Waste Management Program. It has been in industrial service for over 30 a, often in severe corrosion environments, but it is still considered a relatively exotic material with limited operating history. This has arisen because of the aerospace applications of this material and the misconception that the high strength-to-weight ratio dominates the choice of this material. In fact, the advantage of titanium lies in its high reliability and excellent corrosion resistance. It has a proven record in seawater heat exchanger service and a demonstrated excellent reliability even in polluted water. For many reasons it is the technically correct choice of material for marine applications. In this report we review the industrial service history of titanium, particularly in hot saline environments, and demonstrate that it is a viable waste container material, based upon this industrial service history and operating experience. (author)

  11. Quasi-static strength and fractography analysis of two dental implants manufactured by direct metal laser sintering.

    Science.gov (United States)

    Gehrke, Sergio Alexandre; Pérez-Díaz, Leticia; Dedavid, Berenice Anina

    2018-01-30

    New manufacturing methods was developed to improve the tissues integration with the titanium alloy pieces. The present in vitro study was to assess the resistance and fracture mode after applied a quasi-static compressive force on the two dental implants manufactured by direct metal laser sintering. Twenty dental implants manufactured by direct metal laser sintering, using titanium alloy (Ti-6Al-4V) granules in two designs (n = 10 per group): Conventional dental implant (group Imp1) two-piece implant design, where the surgical implant and prosthetic abutment are two separate components and, the one-piece implant (group Imp2), where the surgical implant and prosthetic abutment are one integral piece. All samples were subjected to quasi-static loading at a 30° angle to the implant axis in a universal testing machine. The mean fracture strengths were 1269.2 ± 128.8 N for the group Imp1 and, 1259.5 ± 115.1 N for the group Imp2, without statistical differences (P = .8722). In both groups, the fracture surface does not present crack between the compact core and the superficial (less dense and porous) part of the implants. Based on the measured resistance data for the two implant models manufactured by direct metal laser sintering tested in the present study, we can suggest that they have adequate capacity to withstand the masticatory loads. © 2018 Wiley Periodicals, Inc.

  12. Surface modification of titanium and titanium alloys by ion implantation.

    Science.gov (United States)

    Rautray, Tapash R; Narayanan, R; Kwon, Tae-Yub; Kim, Kyo-Han

    2010-05-01

    Titanium and titanium alloys are widely used in biomedical devices and components, especially as hard tissue replacements as well as in cardiac and cardiovascular applications, because of their desirable properties, such as relatively low modulus, good fatigue strength, formability, machinability, corrosion resistance, and biocompatibility. However, titanium and its alloys cannot meet all of the clinical requirements. Therefore, to improve the biological, chemical, and mechanical properties, surface modification is often performed. In view of this, the current review casts new light on surface modification of titanium and titanium alloys by ion beam implantation. (c) 2010 Wiley Periodicals, Inc.

  13. Sintering uranium oxide in the reaction product of hydrogen-carbon dioxide mixtures

    International Nuclear Information System (INIS)

    De Hollander, W.R.; Nivas, Y.

    1975-01-01

    Compacted pellets of uranium oxide alone or containing one or more additives such as plutonium dioxide, gadolinium oxide, titanium dioxide, silica, and alumina are heated to 900 to 1599 0 C in the presence of a mixture of hydrogen and carbon dioxide, either alone or with an inert carrier gas and held at the desired temperature in this atmosphere to sinter the pellets. The sintered pellets are then cooled in an atmosphere having an oxygen partial pressure of 10 -4 to 10 -18 atm of oxygen such as dry hydrogen, wet hydrogen, dry carbon monoxide, wet carbon monoxide, inert gases such as nitrogen, argon, helium, and neon and mixtures of ayny of the foregoing including a mixture of hydrogen and carbon dioxide. The ratio of hydrogen to carbon dioxide in the gas mixture fed to the furnace is controlled to give a ratio of oxygen to uranium atoms in the sintered particles within the range of 1.98:1 to about 2.10:1. The water vapor present in the reaction products in the furnace atmosphere acts as a hydrolysis agent to aid removal of fluoride should such impurity be present in the uranium oxide. (U.S.)

  14. Effect of additives on enhanced sintering and grain growth in uranium dioxide

    International Nuclear Information System (INIS)

    Bourgeois, L.

    1992-06-01

    The use of sintering additives has been the most effective way of promoting grain growth of uranium dioxide. We have established a same mechanism for additives which belongs to corundum structure: chromium, aluminium, vanadium and titanium sesquioxides. Study of thermodynamical stabilities of dopants has lead to define suitable sintering atmospheres in order to enhance grain growth. Low solubility limits have been defined at T=1700 deg C for four additives, from variations of final grain size versus initial dopant concentration Identification of second phase after cooling has been done from electronic diffraction patterns. It appears that these solubilities decrease sharply as positive deviation from stoichiometry of uranium dioxide increases. Dilatometric analysis of sintering of doped uranium dioxide has shown in certain cases some enhancement in densification rates, at the point of onset of abnormal grain growth, which is believed to be the source. Nevertheless, the following growth is accompanied with pores coalescence mechanisms and pores entrapment inside grains. Increased thermal stability, during standard annealing, is expected, limiting thereby redensification of nuclear fuel in reactors. Finally, from investigations of additives vaporizations, Al 2 O 3 and Cr 2 O 3 , oxygen exchanges between additives and matrix are believed to occur, which should lead to enhance pore mobility. (Author)., refs., figs., tabs

  15. Pore Formation Process of Porous Ti3SiC2 Fabricated by Reactive Sintering

    Directory of Open Access Journals (Sweden)

    Huibin Zhang

    2017-02-01

    Full Text Available Porous Ti3SiC2 was fabricated with high purity, 99.4 vol %, through reactive sintering of titanium hydride (TiH2, silicon (Si and graphite (C elemental powders. The reaction procedures and the pore structure evolution during the sintering process were systematically studied by X-ray diffraction (XRD and scanning electron microscope (SEM. Our results show that the formation of Ti3SiC2 from TiH2/Si/C powders experienced the following steps: firstly, TiH2 decomposed into Ti; secondly, TiC and Ti5Si3 intermediate phases were generated; finally, Ti3SiC2 was produced through the reaction of TiC, Ti5Si3 and Si. The pores formed in the synthesis procedure of porous Ti3SiC2 ceramics are derived from the following aspects: interstitial pores left during the pressing procedure; pores formed because of the TiH2 decomposition; pores formed through the reactions between Ti and Si and Ti and C powders; and the pores produced accompanying the final phase synthesized during the high temperature sintering process.

  16. Thermogravimetric experiments with titanium

    International Nuclear Information System (INIS)

    Porter, L.J.; Longhurst, G.R.

    1991-02-01

    In the process of preparing for pyrophoricity experiments involving uranium, we conducted hydriding and air-exposure experiments on titanium. In these experiments the hydriding reactions and response to air-exposure was generally within the range expected based on work reported by others. One aberrant behavior was a sudden weight gain followed by a significant weight loss. We speculate that loss may be due to hydrogen evolution from the TiH 2 resulting from local heating by oxidation reactions. We verified that titanium is not pyrophoric at temperatures less than 750 degree C. 18 refs. 1 fig

  17. A study on some properties of sintered stainless steel powder compacts with sintering conditions

    International Nuclear Information System (INIS)

    Lee, Bang Sik; Kim, Kwan Hyu; Lee, Doh Jae; Choi, Dap Chun

    1986-01-01

    Sintered specimens for the mechanical and corrosion tests were prepared from 316L, 410L and 434L stainless steel powder compacts with green densities in the range of 6.2∼7.0g/cm 3 . The experimental variables studied were green density, sintering atmosphere, temperature and time, type of lubricant used and cooling rate after sintering operation. Mechanical properties of green compacts and sintered specimens were evaluated. The corrosion tests were performed by potentiodynamic anodic polarization technique. Mechanical properties were very sensitive to the sintering atmosphere; sintering in dissociated ammonia resulted in the strengthing but embrittlement of sintered 316L, 410L and 434L strainless steel powder compacts. Their corrosion resistance was also decreased. The tensile strength was increased with increases in sintering time and temperature while the decreases in the yield strength were observed. The tensile properties of green compacts were shown to closely related to the green density. Addition of 1% acrawax as a lubricant was appeared to be most effective for the improvement of green strength. (Author)

  18. 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

  19. 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.)

  20. Evaluation of preconceptual plug designs using experts' judgement

    International Nuclear Information System (INIS)

    Sioshansi, F.P.; O'Rourke, J.E.

    1980-03-01

    A number of preconceptual plug designs for an underground nuclear waste repository were to be evaluated based on the available information on plug materials and placement techniques. Because of complex environment and loading conditions, long time frame under consideration, rigid performance characteristics and considerable uncertainties present in preconceptual design and material properties, a qualitative and judgmental evaluation procedure was needed to supplement technical studies. A structured procedure was developed to qualitatively capture evaluator's views and reservations on the proposed preconceptual schemes. Since a thorough evaluation of each proposed plug scheme required in-depth experience and familiarity with many components of the plug, three knowledgeable experts with specialties in the most relevant aspects of the problem were independently interviewed. Each plug scheme was broken down into three subcomponents and each subcomponent was evaluated separately. The proposed schemes were then rated taking their subcomponents into consideration. Because the experts had different specialties, their subcomponent and overall ratings were not in full agreement. Each plug scheme's lowest overall rating was used as the most significant determinant of the judgmental preference categories reported in this study. The approach used discriminated between the proposed schemes for those with highest probability of being successful. The most preferred schemes were then reviewed with respect to the data produced in the technical analysis performed during the project. The results of the judgmental analysis were then synthesized and modified with results of the technical analysis to produce the preconceptual plug designs

  1. Development of weld plugging for steam generator tubes of FBR

    International Nuclear Information System (INIS)

    Shimoyama, T.; Matsuyama, T.; Matsumoto, O.; Nagura, Y.; Nakamura, H.; Tohguchi, Y.; Kurokawa, M.; Fukada, T.

    2002-01-01

    This study was undertaken to develop a method of weld plugging of the heat-exchanger tubes of steam generator of Prototype FBR 'MONJU' in case these tubes are damaged for some reason. We studied mainly the shape of plug, welding procedure and effect of postweld heat treatment (PWHT). Evaporator tube sheet, tube and plug are made of 2-1/4Cr-1Mo steel and usually preheating and PWHT will be required for welding of this steel. The results of this study is as follows. 1) Plug was designed to make butt joint welding with grooved tube sheet around the tube hole to satisfy the requirements of plug designing, stress analysis, and good weldability. 2) TIG welding process was selected and certified its good weldability and good performance. 3) PWHT can be done by using high frequency induction heating method locally and also designing the plug to weld joint with tube sheet which was grooved around the tube hole. 4) Mock up test was done and it was certified that this plugging procedure has good weldability and good performance ability for Non Destructive Inspection. (author)

  2. Borehole plugging by hydrothermal transport. A feasibility report

    International Nuclear Information System (INIS)

    Roy, D.M.; White, W.B.

    1975-01-01

    The possibility of forming borehole plugs by hydrothermal transport was examined with respect to five systems, utilizing available literature data. In general, it would appear possible to create plugs with hydrothermal cements, with hydrothermally transported quartz, and with carbonates precipitated in-situ using carbon dioxide or carbon dioxide and water as reacting fluids. Hydrothermal cements appear to be most feasible from an engineering and economic point of view using a slurry with a lime-alumina-silica composition carried into the hole in a single pipe at temperatures in the range of 200 0 C and requiring only enough pressure to drive the mixture into the hole. Quartz or chalcedony plugs would be the most impervious, have the lowest chemical reactivity with groundwater, the lowest thermal expansion, and be most compatible with the wall rock. Deposition is likely to be slow, and there are severe engineering problems associated with a single pipe system carrying silica-rich solutions at temperatures in excess of 500 0 C at pressure of 2000 bars (30,000 psi). Calcite plugs could be formed as compatible plug materials in contact with a limestone or dolomite wall rock. It is not known whether non-porous plugs can be readily formed and there is also a problem of chemical reaction with percolating groundwater. The clay-water and sulfur-water systems do not appear to be viable plug systems. In-situ reconstitution of the wall rock does not appear to be an economically feasible possibility

  3. Final design of ITER port plug test facility

    Energy Technology Data Exchange (ETDEWEB)

    Cerisier, Thierry, E-mail: thierry.cerisier@yahoo.fr [ITER Organization, Route de Vinon-sur-Verdon, CS 90046, St Paul-lez-Durance Cedex, 13067 (France); Levesy, Bruno [ITER Organization, Route de Vinon-sur-Verdon, CS 90046, St Paul-lez-Durance Cedex, 13067 (France); Romannikov, Alexander [Institution “Project Center ITER”, Kurchatov sq. 1, Building 3, Moscow 123182 (Russian Federation); Rumyantsev, Yuri [JSC “Cryogenmash”, Moscow reg., Balashikha 143907 (Russian Federation); Cordier, Jean-Jacques; Dammann, Alexis [ITER Organization, Route de Vinon-sur-Verdon, CS 90046, St Paul-lez-Durance Cedex, 13067 (France); Minakov, Victor; Rosales, Natalya; Mitrofanova, Elena [JSC “Cryogenmash”, Moscow reg., Balashikha 143907 (Russian Federation); Portone, Sergey; Mironova, Ekaterina [Institution “Project Center ITER”, Kurchatov sq. 1, Building 3, Moscow 123182 (Russian Federation)

    2016-11-01

    Highlights: • We introduce the port plug test facility (purpose and status of the design). • We present the PPTF sub-systems. • We present the environmental and functional tests. • We present the occupational and nuclear safety functions. • We conclude on the achievements and next steps. - Abstract: To achieve the overall ITER machine availability target, the availability of diagnostics and heating port plugs shall be as high as 99.5%. To fulfill this requirement, it is mandatory to test the port plugs at operating temperature before installation on the machine and after refurbishment. The ITER port plug test facility (PPTF) is composed of several test stands that can be used to test the port plugs whereas at the end of manufacturing (in a non-nuclear environment), or after refurbishment in the ITER hot cell facility. The PPTF provides the possibility to perform environmental (leak tightness, vacuum and thermo-hydraulic performances) and functional tests (radio frequency acceptance tests, behavior of the plugs’ steering mechanism and calibration of diagnostics) on upper and equatorial port plugs. The final design of the port plug test facility is described. The configuration of the standalone test stands and the integration in the hot cell facility are presented.

  4. Maintenance and plugging technology for CANDU steam generator tubing

    International Nuclear Information System (INIS)

    Prince, J.; Nicholson, A.; Hare, J.; McGoey, L.; Stafford, T.; Gowthorpe, P.

    2006-01-01

    In order to keep aging steam generators in service and to successfully manage the life of these critical components, the capability must exist to perform tube plugging and other complex maintenance activities in-situ. In the early days of CANDU steam generator operation, the only option was to perform these activities manually, which had inherent safety and quality risks. The challenge was to be able to perform these activities remotely thus eliminating some of the confined space and radiological exposure risks. The additional challenge was to develop equipment and techniques which would result in significantly improved quality, particularly for the completed plug welds which would be returned to service. Over the past fifteen years, this technology has matured and has produced remarkable results in field application. Some 14000 tube plugs have been successfully installed to date using automated plugging techniques. This paper presents an overview of the development of techniques available to utilities for steam generator tube plugging as well as some highlights of other steam generator tube maintenance activities such as primary side tube removal and tube end damage repair. Aspects covered in the paper include plug and procedure development, automated equipment and manipulators for tool deployment, process controls and personnel requirements. Recently, the steam generator tube plugging performed by OPG has been incorporated into a formal quality program under the requirements of ASME NCA 4000. An overview of the quality program will be presented and details of some of the important aspects of the quality program will be discussed. (author)

  5. Laser sintering of metal powders on top of sintered layers under multiple-line laser scanning

    International Nuclear Information System (INIS)

    Xiao Bin; Zhang Yuwen

    2007-01-01

    A three-dimensional numerical model for multiple-line sintering of loose powders on top of multiple sintered layers under the irradiation of a moving Gaussian laser beam is carried out. The overlaps between vertically deposited layers and adjacent lines which strengthen bonding are taken into account. The energy equation is formulated using the temperature transforming model and solved by the finite volume method. The effects of the number of the existing sintered layers, porosity and initial temperature coupled with the optimal combination laser intensity and scanning velocity are presented. The results show that the liquid pool moves slightly towards the negative scanning direction and the shape of the liquid pool becomes shallower with higher scanning velocity. A higher laser intensity is needed to achieve the required overlaps when the number of the existing sintered layers increases. Increasing porosity or initial temperature enhances the sintering process and thus less intensity is needed for the overlap requirement

  6. Microarc oxidized TiO2 based ceramic coatings combined with cefazolin sodium/chitosan composited drug film on porous titanium for biomedical applications.

    Science.gov (United States)

    Wei, Daqing; Zhou, Rui; cheng, Su; Feng, Wei; Li, Baoqiang; Wang, Yaming; Jia, Dechang; Zhou, Yu; Guo, Haifeng

    2013-10-01

    Porous titanium was prepared by pressureless sintering of titanium beads with diameters of 100, 200, 400 and 600 μm. The results indicated that the mechanical properties of porous titanium changed significantly with different bead diameters. Plastic deformations such as necking phenomenon and dimple structure were observed on the fracture surface of porous titanium sintered by beads with diameter of 100 μm. However, it was difficult to find this phenomenon on the porous titanium with a titanium bead diameter of 600 μm. The microarc oxidized coatings were deposited on its surface to improve the bioactivity of porous titanium. Furthermore, the cefazolin sodium/chitosan composited films were fabricated on the microarc oxidized coatings for overcoming the inflammation due to implantation, showing good slow-release ability by addition of chitosan. And the release kinetic process of cefazolin sodium in composited films could be possibly fitted by a polynomial model. Copyright © 2013 Elsevier B.V. All rights reserved.

  7. Mechanical and thermo-mechanical analyses of the tapered plug for plugging of deposition tunnels. A feasibility study

    Energy Technology Data Exchange (ETDEWEB)

    Faelth, Billy (Clay Technology AB, Lund (Sweden)); Gatter, Patrik (Vattenfall Power Consultant AB, Stockholm (Sweden))

    2009-09-15

    This report presents results from a study that was carried out in order to examine the applicability of the tapered plug concept for plugging of deposition tunnels in the deep repository for spent nuclear fuel. The report presents results from mechanical and thermo-mechanical models of the tapered plug. The models were analyzed with 3DEC. The models included a portion of a deposition tunnel and its intersection with a main tunnel. In the deposition tunnel, a tapered concrete plug was installed. The plug was subjected to the combined load from the swelling backfill material and from pore pressure inside the deposition tunnel. The thermo-mechanical effects due to the heat generation in the spent fuel were also included in the analyses. Generic material parameter values for the concrete were used. The following items were studied: - Stresses and displacements in the plug. - Shear stresses and shear displacements in the rock-concrete interface. - Stress additions in the rock due to the loads. The sensitivity of the results to changes of constitutive models, to changes of the plug geometry and to pore water pressure in the rock-concrete interface was examined. The results indicate that the displacements in the plug will be within reasonable ranges but the stresses may locally be high enough that they exceed acceptable levels. However, they can be reduced by choice of advantageous plug geometry and by having a good rock-concrete bond. The results also show that the stress additions in the rock due to the thermal load may yield stresses that locally exceed the spalling strength of the rock. At most locations, however, the rock stresses will amount at lower levels. It was concluded that, with choice of an appropriate design, the tapered plug seems to be an applicable concept for plugging of deposition tunnels. It was also concluded that further studies of the tapered plug concept should use material properties parameter values for low-pH concrete. Further, they should also

  8. 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)

  9. DEMO port plug design and integration studies

    Science.gov (United States)

    Grossetti, G.; Boccaccini, L. V.; Cismondi, F.; Del Nevo, A.; Fischer, U.; Franke, T.; Granucci, G.; Hernández, F.; Mozzillo, R.; Strauß, D.; Tran, M. Q.; Vaccaro, A.; Villari, R.

    2017-11-01

    The EUROfusion Consortium established in 2014 and composed by European Fusion Laboratories, and in particular the Power Plant Physics and Technology department aims to develop a conceptual design for the Fusion DEMOnstration Power Plant, DEMO. With respect to present experimental machines and ITER, the main goals of DEMO are to produce electricity continuously for a period of about 2 h, with a net electrical power output of a few hundreds of MW, and to allow tritium self-sufficient breeding with an adequately high margin in order to guarantee its planned operational schedule, including all planned maintenance intervals. This will eliminate the need to import tritium fuel from external sources during operations. In order to achieve these goals, extensive engineering efforts as well as physics studies are required to develop a design that can ensure a high level of plant reliability and availability. In particular, interfaces between systems must be addressed at a very early phase of the project, in order to proceed consistently. In this paper we present a preliminary design and integration study, based on physics assessments for the EU DEMO1 Baseline 2015 with an aspect ratio of 3.1 and 18 toroidal field coils, for the DEMO port plugs. These aim to host systems like electron cyclotron heating launchers currently developed within the Work Package Heating and Current Drive that need an external radial access to the plasma and through in-vessel systems like the breeder blanket. A similar approach shown here could be in principle followed by other systems, e.g. other heating and current drive systems or diagnostics. The work addresses the interfaces between the port plug and the blanket considering the helium-cooled pebble bed and the water cooled lithium lead which are two of four breeding blanket concepts under investigation in Europe within the Power Plant Physics and Technology Programme: the required openings will be evaluated in terms of their impact onto the

  10. The viscoelastic properties of the cervical mucus plug

    DEFF Research Database (Denmark)

    Kjær Bastholm, Sara; Becher, Naja; Stubbe, Peter Reimer

    2013-01-01

    The objective of this study was to characterize the viscoelastic properties of cervical mucus plugs (CMPs) shed during labor at term. Spontaneously shed cervical mucus plugs from healthy women in active labor, were tested. The viscoelastic properties of cervical mucus plugs were investigated...... with using frequency and stress sweep experiments within the linear viscoelastic region. Random-effects regression was used for statistical analysis. The CMPs are solid-like viscoelastic structures and the elastic modulus dominated the viscous modulus at all frequencies. These rheological characteristics...

  11. 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.

  12. Titanium and zirconium alloys

    International Nuclear Information System (INIS)

    Pinard Legry, G.

    1994-01-01

    Titanium and zirconium pure and base alloys are protected by an oxide film with anionic vacancies which gives a very good resistance to corrosion in oxidizing medium, in some ph ranges. Results of pitting and crevice corrosion are given for Cl - , Br - , I - ions concentration with temperature and ph dependence, also with oxygenated ions effect. (A.B.). 32 refs., 6 figs., 3 tabs

  13. 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)

  14. Sintered cobalt-rare earth intermetallic product

    International Nuclear Information System (INIS)

    Benz, M.C.

    1975-01-01

    A process is described for preparing novel sintered cobalt--rare earth intermetallic products which can be magnetized to form permanent magnets having stable improved magnetic properties. A cobalt--rare earth metal alloy is formed having a composition which at sintering temperature falls outside the composition covered by the single Co 5 R intermetallic phase on the rare earth richer side. The alloy contains a major amount of the Co 5 R intermetallic phase and a second solid CoR phase which is richer in rare earth metal content than the Co 5 R phase. The specific cobalt and rare earth metal content of the alloy is substantially the same as that desired in the sintered product. The alloy, in particulate form, is pressed into compacts and sintered to the desired density. The sintered product is comprised of a major amount of the Co 5 R solid intermetallic phase and up to about 35 percent of the product of the second solid CoR intermetallic phase which is richer in rare earth metal content than the Co 5 R phase

  15. HEPA-filter smoke plugging problem

    International Nuclear Information System (INIS)

    Gaskill, J.R.; Magee, M.W.

    1975-01-01

    Actual experiences indicate that during the early stages of a fire, pyrolysis and incomplete combustion of organic materials used in the furnishings or interior finishes of laboratories yield copious quantities of smoke particulates, both liquid and solid. Furthermore, the use of fire retardants in materials used for the above purpose interferes with the combustion process, so that burning of such materials in later stages of a fire will yield dense smoke. These particulates can plug up a HEPA filter or even a more porous prefilter, and thus effectively shut off the exhaust ventilation. In this case, the fire room will pressurize and contamination may spread in an uncontrolled manner. Both small- and large-scale tests have been conducted to evaluate the nature and degree of the problem as a function of materials involved, rate of exposure to the fire, and kinds and temperatures of smoke so generated. Some test work has also been done on scrubbing of smoke. Proposed future work is described. (U.S.)

  16. Amplatzer vascular plugs in congenital cardiovascular malformations

    International Nuclear Information System (INIS)

    Barwad, Parag; Ramakrishnan, Sivasubramanian; Kothari, Shyam S; Saxena, Anita; Gupta, Saurabh K; Juneja, Rajnish; Gulati, Gurpreet Singh; Jagia, Priya; Sharma, Sanjiv

    2013-01-01

    Amplatzer vascular plugs (AVPs) are devices ideally suited to close medium-to-large vascular communications. There is limited published literature regarding the utility of AVPs in congenital cardiovascular malformations (CCVMs). To describe the use of AVPs in different CCVMs and to evaluate their safety and efficacy. All patients who required an AVP for the closure of CCVM were included in this retrospective review of our catheterization laboratory data. The efficacy and safety of AVPs are reported. A total of 39 AVPs were implanted in 31 patients. Thirteen (33%) were AVP type I and 23 (59%) were AVP type II. AVP type III were implanted in two patients and type IV in one patient. The major indications for their use included closure of pulmonary arteriovenous malformation (AVM) (n = 7), aortopulmonary collaterals (n = 7), closure of a patent Blalock-Taussig shunt (n = 5), systemic AVM (n = 5), coronary AVM (n = 4), patent ductus arteriosus (PDA) (n = 3), pulmonary artery aneurysms (n = 3), and venovenous collaterals (n = 2). Deployment of the AVP was done predominantly via the 5 – 7F Judkin's right coronary guide catheter. Overall 92% of the AVPs could be successfully deployed and resulted in occlusion of the target vessel in all cases, within 10 minutes. No procedure-related or access site complication occurred. AVPs are versatile, easy to use, and effective devices to occlude the vascular communications in a variety of settings. AVP II is especially useful in the closure of tubular structures with a high flow

  17. 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.

  18. Influence of sintering temperature on mechanical properties of spark plasma sintered pre-alloyed Ti-6Al-4 V powder

    Energy Technology Data Exchange (ETDEWEB)

    Muthuchamy, A.; Patel, Paridh; Rajadurai, M. [VIT Univ., Vellore, Tamil Nadu (India); Chaurisiya, Jitendar K. [NIT, Suratkal (India); Annamalai, A. Raja [VIT Univ., Vellore, Tamil Nadu (India). Centre for Innovative Manufacturing Research

    2018-04-01

    Spark plasma sintering provides faster heating that can create fully, or near fully, dense samples without significant grain growth. In this study, pre-alloyed Ti-6Al-4 V powder compact samples produced through field assisted sintering in a spark plasma sintering machine are compared as a function of consolidation temperature. The effect of sintering temperature on the densification mechanism, microstructural evolution and mechanical properties of spark plasma sintered Ti-6Al-4 V alloy compacts was investigated in detail. The compact, sintered at 1100 C, exhibited near net density, highest hardness and strength as compared to the other compacts processed at a temperature lower than 1100 C.

  19. Sintering method for nuclear fuel pellet

    International Nuclear Information System (INIS)

    Omuta, Hirofumi; Nakabayashi, Shigetoshi.

    1997-01-01

    When sintering a compressed nuclear fuel powder in an atmosphere of a mixed gas comprising hydrogen and nitrogen, steams are added to the mixed gas to suppress the nitrogen content in sintered nuclear fuel pellets. In addition, the content of nitrogen impurities in the nuclear fuel pellets can be controlled by controlling the amount of steams to be added to the mixed gas, namely, by controlling the dew point as an index thereof. If the addition amount of steams to the mixed gas is determined by controlling the dew point as an index, the content of nitrogen impurities in the sintered nuclear fuel pellets can be controlled reliably to a specified value of 0.0075% or less. If ammonolyzed gas is used as the mixed gas, a more economical mixed gas can be obtained than in the case of forming mixed gas by mixing the hydrogen gas and the nitrogen gas. (N.H.)

  20. 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

  1. 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.)

  2. Mechanical Properties of Plug Welds after Micro-Jet Cooling

    Directory of Open Access Journals (Sweden)

    Hadryś D.

    2016-12-01

    Full Text Available New technology of micro-jet welding could be regarded as a new way to improve mechanical properties of plug welds. The main purpose of that paper was analyzing of mechanical properties of plug welds made by MIG welding method with micro-jet cooling. The main way for it was comparison of plug welds made by MIG welding method with micro-jet cooling and plug welds made by ordinary MIG welding method. It is interesting for steel because higher amount of acicular ferrite (AF in weld metal deposit (WMD is obtained in MIG welding method with micro-jet cooling in relation to ordinary MIG welding method. This article presents the influence of the cooling medium and the number of micro-jet streams on mechanical properties of the welded joint. Mechanical properties were described by force which is necessary to destroy weld joint.

  3. Waste isolation pilot plant (WIPP) borehole plugging program description

    International Nuclear Information System (INIS)

    Christensen, C.L.; Hunter, T.O.

    1979-08-01

    The tests and experiments described attempt to provide a mix of borehole (with limited access) and in-mine (with relatively unlimited access) environments in which assessment of the various issues involved can be undertaken. The Bell Canyon Test provides the opportunity to instrument and analyze a plug in a high pressure region. The Shallow Hole Test permits application of best techniques for plugging and then access to both the top and bottom of the plug for further analysis. The Diagnostic Test Hole permits recovery of bench scale size samples for analysis and establishes an in-borehole laboratory in which to conduct testing and analysis in all strata from the surface into the salt horizon. The additional in mine experiments provide the opportunity to investigate in more detail specific effects on plugs in the salt region and allows evaluation of instrumentation systems

  4. Rotary plug device for use in LMFBR type reactors

    International Nuclear Information System (INIS)

    Azuma, Kazuhiko; Imayoshi, Sho.

    1988-01-01

    Purpose: To prevent adhesion of sodium in the rotational gap of a rotational plug. Constitution: One of the walls of a cylindrical gap formed between the outer circumference of a small rotary plug and a large rotary plug that constitute a double rotary plug is cooled to lower than the sodium coagulation temperature, while a stater of a linear motor in a cylindrical shape and wound with linear coils around the iron core is attached to the inside of the other of the walls. Then, one of the walls of the gap to which sodium adheres is cooled to less than sodium coagulation temperature, so that sodium is or tends to be deposited to the wall. Then, eddy currents are resulted to sodium by the current supplied to the stater of the linear motor attached to the other of the walls, to produce thrusting force. Sodium on the wall surface is scraped off by this. (Yoshihara, H.)

  5. Application of Inductive Monitoring System to Plug Load Anomaly Detection

    Data.gov (United States)

    National Aeronautics and Space Administration — NASA Ames Research Center’s Sustainability Base is a new 50,000 sq. ft. LEED Platinum office building. Plug loads are expected to account for a significant portion...

  6. Modular, Plug and Play, Distributed Avionics, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — The objective of this SBIR effort was to prove the viability of an Ethernet version of the MicroSat Systems, Inc. (MSI) modular, plug and play (PnP) spacecraft...

  7. Setting plug & abandonment barriers with minimum removal of tubulars

    OpenAIRE

    Nessa, Jon Olav

    2012-01-01

    Master's thesis in Petroleum engineering The useful life of an offshore well is determined by the reserves which it contacts, the pressure support within the reservoir and the continued integrity of the wellbore. When a well has reached the end of its lifetime, plugging operations have to be conducted before permanent abandonment. Conventional Plug and Abandonment (P&A) operations will often require removing a section of the casing in order to create cross sectional barriers for well aband...

  8. Engineering activities on the ITER representative diagnostic equatorial port plug

    International Nuclear Information System (INIS)

    Meunier, L.; Doceul, L.; Salasca, S.; Martins, J.-P.; Jullien, F.; Dechelle, Christian; Bidaud, Pierre; Pilard, Vincent; Terra, Alexis; Ogea, Mathieu; Ciattaglia, Emanuela; Walker, Christopher

    2009-01-01

    Most of ITER diagnostic systems are integrated in port plugs, which are water cooled stainless steel structures inserted into the vacuum vessel ports. The port plug must provide basic functions such as neutron and gamma shielding, supporting the first wall armour (BSM), closing the vacuum vessel ports, while supporting the diagnostic equipments. ITER diagnostic port plug must resist a severe environment like high temperature due to neutron interaction with the structures and high electromechanical loading during disruptions events. CEA has contributed to the design and integration tasks in the frame of the representative equatorial port plug EQ no. 01, in particular on the engineering, structural and thermal finite element analysis. These detailed analyses have highlighted some design issues which were worked out through different solutions. This paper contains a description of the engineering activities performed such as: -The static mechanical calculations of the top plate closure system under disruption load. -The static mechanical calculations of the BSM attachment to the port plug. These two first studies led to design changes proposals which significantly improved the behaviour of the structures but also showed that the safety margin with respect to design limits is quite low. -The design of a Diagnostic Shield Module (DSM) integrated inside the port plug and a proposition of attachment scheme, with respect to disruption loads. The manufacturing of the DSM has been taken into account, as well as diagnostic integration inside the structure and maintenance aspects. -The thermal assessment of the port plug under neutronic load during normal operation, with the optimization of the cooling system. The maximum temperature calculated in normal operation has been reduced from 900 deg. C to less than 400 deg. C in the front plate; and the cooling arrangement at the back of the port plug has been simplified without important temperature increase.

  9. Engineering activities on the ITER representative diagnostic equatorial port plug

    Energy Technology Data Exchange (ETDEWEB)

    Meunier, L. [Association Euratom CEA, CEA/DSM/IRFM (France)], E-mail: lmeunier@cea.fr; Doceul, L.; Salasca, S.; Martins, J.-P.; Jullien, F.; Dechelle, Christian; Bidaud, Pierre; Pilard, Vincent; Terra, Alexis; Ogea, Mathieu [Association Euratom CEA, CEA/DSM/IRFM (France); Ciattaglia, Emanuela [EFDA CSU, Garching (Germany); Walker, Christopher [ITER International Organisation (France)

    2009-06-15

    Most of ITER diagnostic systems are integrated in port plugs, which are water cooled stainless steel structures inserted into the vacuum vessel ports. The port plug must provide basic functions such as neutron and gamma shielding, supporting the first wall armour (BSM), closing the vacuum vessel ports, while supporting the diagnostic equipments. ITER diagnostic port plug must resist a severe environment like high temperature due to neutron interaction with the structures and high electromechanical loading during disruptions events. CEA has contributed to the design and integration tasks in the frame of the representative equatorial port plug EQ no. 01, in particular on the engineering, structural and thermal finite element analysis. These detailed analyses have highlighted some design issues which were worked out through different solutions. This paper contains a description of the engineering activities performed such as: -The static mechanical calculations of the top plate closure system under disruption load. -The static mechanical calculations of the BSM attachment to the port plug. These two first studies led to design changes proposals which significantly improved the behaviour of the structures but also showed that the safety margin with respect to design limits is quite low. -The design of a Diagnostic Shield Module (DSM) integrated inside the port plug and a proposition of attachment scheme, with respect to disruption loads. The manufacturing of the DSM has been taken into account, as well as diagnostic integration inside the structure and maintenance aspects. -The thermal assessment of the port plug under neutronic load during normal operation, with the optimization of the cooling system. The maximum temperature calculated in normal operation has been reduced from 900 deg. C to less than 400 deg. C in the front plate; and the cooling arrangement at the back of the port plug has been simplified without important temperature increase.

  10. Nanosatellite and Plug-and-Play Architecture 2 (NAPA 2)

    Science.gov (United States)

    2017-02-28

    development of a 6U- format Space Plug-and-play Architecture (SPA) Research Cubesat (SPARC). SPARC-1 (first and only pursued under this PA) demonstrates...development of a six unit (6U)- format Space Plug-and-play Architecture (SPA) Research Cubesat (SPARC). SPARC-1 (first and only pursued under this PA...computers – More capable, more centralized, bigger wiring bundle Elimination of central computers, distribution of intelligence in systems Rad- hard

  11. Electric and Plug-In Hybrid Electric Fleet Vehicle Testing | Transportation

    Science.gov (United States)

    Research | NREL Electric and Plug-In Hybrid Electric Fleet Vehicle Evaluations Electric and Plug-In Hybrid Electric Fleet Vehicle Evaluations How Electric and Plug-In Hybrid Electric Vehicles plugging the vehicle into an electric power source. PHEVs are powered by an internal combustion engine that

  12. Reconstitutable control assembly having removable control rods with detachable split upper end plugs

    International Nuclear Information System (INIS)

    Gjertsen, R.K.; Knott, R.P.; Sparrow, J.A.

    1991-01-01

    This patent describes, for use in facilitating replacement of a neutron absorber control rod on a control assembly spider structure, an end plug. It comprises a pair of separate upper and lower plug portions; the upper section of the upper plug portion being configured for rigid attachment; the middle section of the upper plug portion having angularly displaced flat surfaces formed on the exterior

  13. Combustion of fuels with low sintering temperature

    Energy Technology Data Exchange (ETDEWEB)

    Dalin, D

    1950-08-16

    A furnace for the combustion of low sintering temperature fuel consists of a vertical fuel shaft arranged to be charged from above and supplied with combustion air from below and containing a system of tube coils extending through the fuel bed and serving the circulation of a heat-absorbing fluid, such as water or steam. The tube-coil system has portions of different heat-absorbing capacity which are so related to the intensity of combustion in the zones of the fuel shaft in which they are located as to keep all parts of the fuel charge below sintering temperature.

  14. Fusibility and sintering characteristics of ash

    Energy Technology Data Exchange (ETDEWEB)

    Ots, A. A., E-mail: aots@sti.ttu.ee [Tallinn University of Technology (Estonia)

    2012-03-15

    The temperature characteristics of ash fusibility are studied for a wide range of bituminous and brown coals, lignites, and shales with ratios R{sub B/A} of their alkaline and acid components between 0.03 and 4. Acritical value of R{sub 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.

  15. Numerical simulation of ion confinement in the Phaedrus plugs

    International Nuclear Information System (INIS)

    Horne, S.F.

    1984-01-01

    Neutral beams of up to 60 amps were injected into the plugs of the tandem mirror Phaedrus. Substantial heating of the target RF-sustained plasma has been observed, but fueling has been negligible. In order to understand the lack of significant fueling, a model of the trapping and loss processes occurring in the Phaedrus plug was developed, and is presented in this thesis. The model includes neutral beam effects, RF trapping, Coulomb losses, and charge exchange on background gas, in a framework which includes finite gyro-orbit effects. A numerical simulation based on the model is compared to data from 2XIIB and TMX, and shows good agreement. The model is then applied to the Phaedrus plugs, and compared to RF-sustained and neutral-beam data obtained during machine operation in hydrogen and deuterium. The modeling of the Phaedrus plugs indicates that during beam injection, a two-step process occurs that results in the rapid loss of ions. Charge exchange of trapped plasma on the energetic neutral beam causes rapid radial diffusion of the plasma, which then charge exchanges on the background gas, or is lost to the limiter. Because this is a finite gyro-orbit effect, increasing the plug magnetic field should improve the net beam fueling by reducing this diffusion. Results from the model indicate that increasing the plug midplane field from 2600 to 4000 gauss will improve the beam fueling significantly

  16. Current state of the Uranium dioxide sintering theory

    International Nuclear Information System (INIS)

    Baranov, V.; Devyatko, Y.; Tenishev, A.; Khlunov, A.; Khomyakov, O.

    2011-01-01

    The basic approaches to the description of the ceramics sintering phenomenon are considered. It is established that diffusive sintering models incorrectly describe an intermediate stage of this process. The physical model of sintering, considering the substance plastic flow of pressing under the influence of internal stress forces and capillary forces, as the basic mechanism defining the shrinkage of sintering oxide nuclear fuel, is offered. (authors)

  17. Peculiarities of formation and sintering of fine dispersed molybdenum powders

    International Nuclear Information System (INIS)

    Kalamazov, R.U.; Pak, V.I.; Tsvetkov, Yu.V.; Lem, I.N.

    1989-01-01

    Pressing of fine dispersed Mo powders sintering of compacts in H 2 and vacuum is studied. It is shown that powder preannealing at 600 deg C in H 2 for 2 hours is necessary for formation of dense sintered compacts. Qualitatively choice of pressing conditions is possible when using electron-positron annihilation method. Peculiarities of compacting and sintering of fine- and coarse-dispersed powder mixtures are considered. The obtained results are discussed from the view point of sintering recrystallization mechanism

  18. Complex anal fistulas: plug or flap?

    Science.gov (United States)

    Muhlmann, Mark D; Hayes, Julian L; Merrie, Arend E H; Parry, Bryan R; Bissett, Ian P

    2011-10-01

    Rectal mucosal advancement flaps (RMAF) and fistula plugs (FP) are techniques used to manage complex anal fistulas. The purpose of this study was to review and compare the results of these methods of repair. A retrospective review of all complex anal fistulas treated by either a RMAF or a FP at Auckland City Hospital from 2004 to 2008. Comparisons were made in terms of successful healing rates, time to failure and the use of magnetic resonance imaging. Overall, 70 operations were performed on 55 patients (55.7% male). The mean age was 44.9 years. Twenty-one patients (30%) had had at least one previous unsuccessful repair. Indications for repair included 57 high cryptoglandular anal (81%), 4 Crohn's anal (6%), 7 rectovaginal (10%), 1 rectourethral (1%) and 1 pouch-vaginal fistula (1%). All patients were followed up with a mean of 4.5 months. Forty-eight RMAFs (69% of total) were performed with 16 successful repairs (33%). Twenty-two FPs (31% of total) were performed with 7 successful repairs (32%, P = 0.9). In failed repairs, there was no difference in terms of mean time to failure (RMAF 4.8 months versus FP 4.1 months, P = 0.62). Magnetic resonance imaging was performed in 21 patients (37%) before the repair. The success rate in these patients was 20%. The results of treatment of complex anal fistulas are disappointing. The choice of operation of either a RMAF or a FP did not alter the poor healing rates of about one third of patients in each group.

  19. Amplatzer vascular plugs in congenital cardiovascular malformations

    Directory of Open Access Journals (Sweden)

    Parag Barwad

    2013-01-01

    Full Text Available Background: Amplatzer vascular plugs (AVPs are devices ideally suited to close medium-to-large vascular communications. There is limited published literature regarding the utility of AVPs in congenital cardiovascular malformations (CCVMs. Aims: To describe the use of AVPs in different CCVMs and to evaluate their safety and efficacy. Materials and Methods: All patients who required an AVP for the closure of CCVM were included in this retrospective review of our catheterization laboratory data. The efficacy and safety of AVPs are reported. Results: A total of 39 AVPs were implanted in 31 patients. Thirteen (33% were AVP type I and 23 (59% were AVP type II. AVP type III were implanted in two patients and type IV in one patient. The major indications for their use included closure of pulmonary arteriovenous malformation (AVM (n = 7, aortopulmonary collaterals (n = 7, closure of a patent Blalock-Taussig shunt (n = 5, systemic AVM (n = 5, coronary AVM (n = 4, patent ductus arteriosus (PDA (n = 3, pulmonary artery aneurysms (n = 3, and venovenous collaterals (n = 2. Deployment of the AVP was done predominantly via the 5 - 7F Judkin′s right coronary guide catheter. Overall 92% of the AVPs could be successfully deployed and resulted in occlusion of the target vessel in all cases, within 10 minutes. No procedure-related or access site complication occurred. Conclusions: AVPs are versatile, easy to use, and effective devices to occlude the vascular communications in a variety of settings. AVP II is especially useful in the closure of tubular structures with a high flow.

  20. 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)

  1. Improving NASICON Sinterability through Crystallization under High Frequency Electrical Fields

    Directory of Open Access Journals (Sweden)

    Ilya eLisenker

    2016-03-01

    Full Text Available The effect of high frequency (HF electric fields on the crystallization and sintering rates of a lithium aluminum germanium phosphate (LAGP ion conducting ceramic was investigated. LAGP with the nominal composition Li1.5Al0.5Ge1.5(PO43 was crystallized and sintered, both conventionally and under effect of electrical field. Electrical field application, of 300V/cm at 1MHz, produced up to a 40% improvement in sintering rate of LAGP that was crystallized and sintered under the HF field. Heat sink effect of the electrodes appears to arrest thermal runaway and subsequent flash behavior. Sintered pellets were characterized using XRD, SEM, TEM and EIS to compare conventionally and field sintered processes. The as-sintered structure appears largely unaffected by the field as the sintering curves tend to converge beyond initial stages of sintering. Differences in densities and microstructure after 1 hour of sintering were minor with measured sintering strains of 31% vs. 26% with and without field, respectively . Ionic conductivity of the sintered pellets was evaluated and no deterioration due to the use of HF field was noted, though capacitance of grain boundaries due to secondary phases was significantly increased.

  2. Mechanochemistry of titanium oxides

    Directory of Open Access Journals (Sweden)

    Veljković Ivana

    2009-01-01

    Full Text Available Mechanochemistry represents an alternative route in synthesis of nanomaterials. Mechanochemical routes are attractive because of their simplicity, flexibility, and ability to prepare materials by solid state reactions at room temperature. The aim of this work is the mechanochemical synthesis of nanostructured titanium oxides of different composition starting from mixtures of Ti and TiO2, TiO and TiO2 or Ti2O3 and TiO2. Emphasis is on the Magneli phases Ti4O7 and Ti5O9 because their mixture is commercially known as EBONEX material. The materials prepared were characterized by XRPD, TG/DTA analysis, SEM and optical microscopy. Titanium monoxide and several Magneli oxides, Ti4O7, Ti5O9 and Ti6O11, are successfully prepared. The results are very interesting because the EBONEX materials were prepared at lower than usual temperature, which would decrease the effective cost of production.

  3. Characterization and Electrical Response to Humidity of Sintered Polymeric Electrospun Fibers of Vanadium Oxide-({TiO}_{{2}} /{WO}_{{3}} )

    Science.gov (United States)

    Araújo, E. S.; Libardi, J.; Faia, P. M.; de Oliveira, H. P.

    2018-02-01

    Metal oxide composites have attracted much consideration due to their promising applications in humidity sensors in response to the physical and chemical property modifications of the resulting materials. This work focused on the preparation, microstructural characterization and analysis of humidity-dependent electrical properties of undoped and vanadium oxide (V2O5)-doped titanium oxide/tungsten oxide (TiO2/WO3) sintered ceramic films obtained by electrospinning. The electrical properties were investigated by impedance spectroscopy (400 Hz-40 MHz) as a function of relative humidity (RH). The results revealed a typical transition in the transport mechanisms controlled by the appropriated doping level of V2O5, which introduces important advantages to RH detection due to the atomic substitution of titanium by vanadium atoms in highly doped structures. These aspects are directly related to the microstructure modification and structure fabrication procedure.

  4. A Comparative Study of Cycle Variability of Laser Plug Ignition vs Classical Spark Plug Ignition in Combustion Engines

    Science.gov (United States)

    Done, Bogdan

    2017-10-01

    Over the past 30 years numerous studies and laboratory experiments have researched the use of laser energy to ignite gas and fuel-air mixtures. The actual implementation of this laser application has still to be fully achieved in a commercial automotive application. Laser Plug Ignition as a replacement for Spark Plug Ignition in the internal combustion engines of automotive vehicles, offers several potential benefits such as extending lean burn capability, reducing the cyclic variability between combustion cycles and decreasing the total amount of ignition costs, and implicitly weight and energy requirements. The paper presents preliminary results of cycle variability study carried on a SI Engine equipped with laser Plug Ignition system. Versus classic ignition system, the use of the laser Plug Ignition system assures the reduction of the combustion process variability, reflected in the lower values of the coefficient of variability evaluated for indicated mean effective pressure, maximum pressure, maximum pressure angle and maximum pressure rise rate. The laser plug ignition system was mounted on an experimental spark ignition engine and tested at the regime of 90% load and 2800 rev/min, at dosage of λ=1.1. Compared to conventional spark plug, laser ignition assures the efficiency at lean dosage.

  5. 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

  6. 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.

  7. Blast furnace sinter performance improvement; Melhoria do rendimento de sinter de alto forno

    Energy Technology Data Exchange (ETDEWEB)

    Santos, Ricardo Baeta; Ferreira, Antonio Marcos M.; Perez, Jose Antonio; Nobrega, Carlos A.; Madeira Filho, Nelson Santos; Silva, Jose Coutinho da; Sampaio, Silvio; Larcher, Marcos A.; Silva Filho, Jose Maximo da; Nogueira, Carlos Alberto; Ramalho Filho, Wilson; Costa, Jose Luiz Lage da; Silva, Mauro Correa da [Companhia Siderurgica de Tubarao (CST), Serra, ES (Brazil)

    1995-07-01

    The article discusses the following issues of methodology maid and the accomplished actions aiming at the blast furnace sinter performance improvement: performance concept; performance historical evolution; problem boarding; influence factors; interpretation of the results; actions implementation; and economic benefit.

  8. Industrial experience with titanium

    Energy Technology Data Exchange (ETDEWEB)

    Ikeda, B M; Shoesmith, D W

    1997-09-01

    Titanium is a reference material for the construction of waste containers in the Canadian Nuclear Fuel Waste Management Program. It has been in industrial service for over 30 a, often in severe corrosion environments, but it is still considered a relatively exotic material with limited operating history. This has arisen because of the aerospace applications of this material and the misconception that the high strength-to-weight ratio dominates the choice of this material. In fact, the advantage of titanium lies in its high reliability and excellent corrosion resistance. It has a proven record in seawater heat exchanger service and a demonstrated excellent reliability even in polluted water. For many reasons it is the technically correct choice of material for marine applications. In this report we review the industrial service history of titanium, particularly in hot saline environments, and demonstrate that it is a viable waste container material, based upon this industrial service history and operating experience. (author) 83 refs., 17 tabs., 3 figs.

  9. Advances in titanium alloys

    International Nuclear Information System (INIS)

    Seagle, S.R.; Wood, J.R.

    1993-01-01

    As described above, new developments in the aerospace market are focusing on higher temperature alloys for jet engine components and higher strength/toughness alloys for airframe applications. Conventional alloys for engines have reached their maximum useful temperature of about 1000 F (540 C) because of oxidation resistance requirements. IMI 834 and Ti-1100 advanced alloys show some improvement, however, the major improvement appears to be in gamma titanium aluminides which could extend the maximum usage temperature to about 1500 F (815 C). This puts titanium alloys in a competitive position to replace nickel-base superalloys. Advanced airframe alloys such as Ti-6-22-22S, Beta C TM , Ti-15-333 and Ti-10-2-3 with higher strength than conventional Ti-6-4 are being utilized in significantly greater quantities, both in military and commercial applications. These alloys offer improved strength with little or no sacrifice in toughness and improved formability, in some cases. Advanced industrial alloys are being developed for improved corrosion resistance in more reducing and higher temperature environments such as those encountered in sour gas wells. Efforts are focused on small precious metal additions to optimize corrosion performance for specific applications at a modest increase in cost. As these applications develop, the usage of titanium alloys for industrial markets should steadily increase to approach that for aerospace applications. (orig.)

  10. 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.

  11. 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)

  12. 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

  13. 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

  14. Sintering of magnesia: effect of additives

    Indian Academy of Sciences (India)

    Effect of different additives, namely Cr2O3, Fe2O3 and TiO2, up to 2 wt% was studied on the sinter- ing and .... mental distribution of the components is shown in figure 7. It shows ... Chiang Y M, Birniand D and Kingery W 1996 Physical ceram-.

  15. 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.

  16. Titanium fasteners. [for aircraft industry

    Science.gov (United States)

    Phillips, J. L.

    1972-01-01

    Titanium fasteners are used in large quantities throughout the aircraft industry. Most of this usage is in aluminum structure; where titanium structure exists, titanium fasteners are logically used as well. Titanium fasteners offer potential weight savings to the designer at a cost of approximately $30 per pound of weight saved. Proper and least cost usage must take into consideration type of fastener per application, galvanic couples and installation characteristics of protective coatings, cosmetic appearance, paint adhesion, installation forces and methods available and fatigue performance required.

  17. Joining of Gamma Titanium Aluminides

    National Research Council Canada - National Science Library

    Baeslack, William

    2002-01-01

    .... Although organized and presented by joining process, many of the observations made and relationships developed, particularly those regarding the weldability and welding metallurgy of gamma titanium...

  18. Plug pattern optimization for gamma knife radiosurgery treatment planning

    International Nuclear Information System (INIS)

    Zhang Pengpeng; Wu, Jackie; Dean, David; Xing Lei; Xue Jinyue; Maciunas, Robert; Sibata, Claudio

    2003-01-01

    Purpose: To develop a novel dose optimization algorithm for improving the sparing of critical structures during gamma knife radiosurgery by shaping the plug pattern of each individual shot. Method and Materials: We first use a geometric information (medial axis) aided guided evolutionary simulated annealing (GESA) optimization algorithm to determine the number of shots and isocenter location, size, and weight of each shot. Then we create a plug quality score system that checks the dose contribution to the volume of interest by each plug in the treatment plan. A positive score implies that the corresponding source could be open to improve tumor coverage, whereas a negative score means the source could be blocked for the purpose of sparing normal and critical structures. The plug pattern is then optimized via the GESA algorithm that is integrated with this score system. Weight and position of each shot are also tuned in this procedure. Results: An acoustic tumor case is used to evaluate our algorithm. Compared to the treatment plan generated without plug patterns, adding an optimized plug pattern into the treatment planning process boosts tumor coverage index from 95.1% to 97.2%, reduces RTOG conformity index from 1.279 to 1.167, lowers Paddick's index from 1.34 to 1.20, and trims the critical structure receiving more than 30% maximum dose from 16 mm 3 to 6 mm 3 . Conclusions: Automated GESA-based plug pattern optimization of gamma knife radiosurgery frees the treatment planning team from the manual forward planning procedure and provides an optimal treatment plan

  19. Reduction of surface erosion caused by helium blistering in sintered beryllium and sintered aluminum powder

    International Nuclear Information System (INIS)

    Das, S.K.; Kaminsky, M.

    1976-01-01

    Studies have been conducted to find materials with microstructures which minimize the formation of blisters. A promising class of materials appears to be sintered metal powder with small average grain sizes and low atomic number Z. Studies of the surface erosion of sintered aluminum powder (SAP 895) and of aluminum held at 400 0 C due to blistering by 100 keV helium ions have been conducted and the results are compared to those obtained earlier for room temperature irradiation. A significant reduction of the erosion rate in SAP 895 in comparison to annealed aluminum and SAP 930 is observed. In addition results on the blistering of sintered beryllium powder (type I) irradiated at room temperature and 600 0 C by 100 keV helium ions are given. These results will be compared with those reported recently for vacuum cast beryllium foil and a foil of sintered beryllium powder (type II) which was fabricated differently, than type I. For room temperature irradiation only a few blisters could be observed in sintered beryllium powder type I and type II and they are smaller in size and in number than in vacuum cast beryllium. For irradiation at 600 0 C large scale exfoliation of blisters was observed for vacuum cast beryllium but much less exfoliation was seen for sintered beryllium powder, type I, and type II. The results show a reduction in erosion rate cast beryllium, for both room temperature and 600 0 C

  20. Effect of sintering processing on microstructure, mechanical properties and corrosion resistance of Ti–24Nb–4Zr–7.9Sn alloy for biomedical applications

    International Nuclear Information System (INIS)

    Guo, Shibo; Chu, Aimin; Wu, Haijiang; Cai, Chunbo; Qu, Xuanhui

    2014-01-01

    Highlights: • Ti–24Nb–4Zr–7.9Sn alloy is prepared by powder metallurgy method. • The alloy prepared at 1250 °C for 2 h has more β-matrix and tiny α-precipitation. • The alloy prepared at 1250 °C for 2 h possesses good mechanical properties. • The alloy prepared at 1250 °C for 2 h exhibits better corrosion resistance. - Abstract: Ti–24Nb–4Zr–7.9Sn alloy was prepared by Powder Metallurgy (PM) method using titanium hydride powder, niobium powder, zirconium powder, and tin powder as raw materials. The effect of sintering processing on microstructure, mechanical properties, and corrosion resistance was investigated in details. The alloy possessed dominant β-matrix and a little α-precipitation. The mechanical properties of the alloy sintered at 1250 °C for 2 h were better than those of the alloys with other sintering processing, which would avoid stress shielding and thus prevent bone resorption in orthopedic implants applications. As long-term stability in biological environment is required, the electrochemical behaviors in a simulated body fluid (Hank’s solution and simulated saliva solution) were also evaluated. Potentiodynamic polarization curves exhibited that the sample sintered at 1250 °C for 2 h had better corrosion properties than those of other sintering processing. The good corrosion resistance combined with better mechanical biocompatibility made the Ti–24Nb–4Zr–7.9Sn alloy suitable for use as orthopedic implants

  1. 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 %

  2. High temperature synthesis of ceramic composition by directed reaction of molten titanium or zirconium with boron carbide

    International Nuclear Information System (INIS)

    Johnson, W.B.

    1990-01-01

    Alternative methods of producing ceramics and ceramic composites include sintering, hot pressing and more recently hot isostatic pressing (HIP) and self-propagating high temperature synthesis (SHS). Though each of these techniques has its advantages, each suffers from several restrictions as well. Sintering may require long times at high temperatures and for most materials requires sintering aids to get full density. These additives can, and generally do, change (often degrade) the properties of the ceramic. Hot pressing and hot isostatic pressing are convenient methods to quickly prepare samples of some materials to full density, but generally are expensive and may damage some types of reinforcements during densification. This paper focuses on the preparation and processing of composites prepared by the directed reaction of molten titanium or zirconium with boron carbide. Advantages and disadvantages of this approach when compared to traditional methods are discussed, with reference to specific examples. Examples of microstructure are properties of these materials are reported

  3. The quantitative characterization of sintering of urania powders

    International Nuclear Information System (INIS)

    Das, P.; Kulkarni, U.D.

    1981-01-01

    This paper presents a unified approach towards characterization of the sintering behaviour of UO 2 powders in terms of their extrinsic properties. Empirical equations connecting the sintering index with various powder parameters have been set up. The influence of various powder parameters, either individually or as dimensionless/dimensional groups, on the sintering behaviour has been studied. The relative importance of these factors has also been analysed. A good polynomial fit has been obtained for variation of sintering index with some of the powder parameters and dimensionless/dimensional groups. The equations are expected to provide a good basis for assessing the sinterability of UO 2 powders. (Auth.)

  4. Titanium compacts produced by the pulvimetallurgical hydride-dehydride method for biomedical applications

    Energy Technology Data Exchange (ETDEWEB)

    Barreiro, M M [Materiales Dentales, Facultad de OdontologIa, Universidad de Buenos Aires, Marcelo T de Alvear 2142 (1122), Buenos Aires (Argentina); Grana, D R; Kokubu, G A [PatologIa I. Escuela de OdontologIa, Facultad de Medicina. Asociacion Odontologica Argentina-Universidad del Salvador, Tucuman 1845 (1050) Buenos Aires (Argentina); Luppo, M I; Mintzer, S; Vigna, G, E-mail: mbarreiro@mater.odon.uba.a, E-mail: dgrana@usal.edu.a, E-mail: luppo@cnea.gov.a, E-mail: vigna@cnea.gov.a [Departamento Materiales, Comision Nacional de Energia Atomica, Gral Paz 1499 (B1650KNA), San MartIn, Buenos Aires (Argentina)

    2010-04-15

    Titanium powder production by the hydride-dehydride method has been developed as a non-expensive process. In this work, commercially pure grade two Ti specimens were hydrogenated. The hydrided material was milled in a planetary mill. The hydrided titanium powder was dehydrided and then sieved to obtain a particle size between 37 and 125{mu}m in order to compare it with a commercial powder produced by chemical reduction with a particle size lower than 150{mu}m. Cylindrical green compacts were obtained by uniaxial pressing of the powders at 343 MPa and sintering in vacuum. The powders and the density of sintered compacts were characterized, the oxygen content was measured and in vivo tests were performed in the tibia bones of Wistar rats in order to evaluate their biocompatibility. No differences were observed between the materials which were produced either with powders obtained by the hydride-dehydride method or with commercial powders produced by chemical reduction regarding modifications in compactation, sintering and biological behaviour.

  5. Titanium compacts produced by the pulvimetallurgical hydride-dehydride method for biomedical applications

    International Nuclear Information System (INIS)

    Barreiro, M M; Grana, D R; Kokubu, G A; Luppo, M I; Mintzer, S; Vigna, G

    2010-01-01

    Titanium powder production by the hydride-dehydride method has been developed as a non-expensive process. In this work, commercially pure grade two Ti specimens were hydrogenated. The hydrided material was milled in a planetary mill. The hydrided titanium powder was dehydrided and then sieved to obtain a particle size between 37 and 125 μm in order to compare it with a commercial powder produced by chemical reduction with a particle size lower than 150 μm. Cylindrical green compacts were obtained by uniaxial pressing of the powders at 343 MPa and sintering in vacuum. The powders and the density of sintered compacts were characterized, the oxygen content was measured and in vivo tests were performed in the tibia bones of Wistar rats in order to evaluate their biocompatibility. No differences were observed between the materials which were produced either with powders obtained by the hydride-dehydride method or with commercial powders produced by chemical reduction regarding modifications in compactation, sintering and biological behaviour.

  6. Thermophysical and elastic properties of titanium carbonitrides containing molybdenum and tungsten

    International Nuclear Information System (INIS)

    Matsuda, Tetsushi; Matsubara, Hideaki

    2013-01-01

    Highlights: ► (Ti,Me)(C,N) sintered bodies were prepared by hot-pressing. ► The thermophysical and elastic properties of the carbonitrides were evaluated. ► The porosities of the specimens were less than 1%. ► The Young’s modulus decreases with increasing Mo content. ► The Debye temperatures decrease with increasing Mo/W content. -- Abstract: Titanium carbonitride has good mechanical properties such as high hardness and high Young’s modulus. It is a major raw material for Ti(C,N)-based cermets, and their properties are strongly dependent on the properties of titanium carbonitrides. The thermophysical and elastic properties of the carbonitride need to be systematically investigated, so as to be used for designing cutting tools and wear-resistant tools. The thermophysical and elastic properties of (Ti,Me)(C,N) (Me = Mo. W) sintered bodies prepared by hot-pressing at 2200 °C were evaluated. The porosities of the specimens were less than 1%. The Young’s modulus decreased with increasing Mo, which seems to be the result of vacancy formation. The thermal expansion coefficient, the thermal conductivity and the Debye temperatures of (Ti,Me)(C,N) sintered bodies decreased with increasing Mo/W content

  7. Chemical changes of titanium and titanium dioxide under electron bombardment

    Directory of Open Access Journals (Sweden)

    Romins Brasca

    2007-09-01

    Full Text Available The electron induced effect on the first stages of the titanium (Ti0 oxidation and titanium dioxide (Ti4+ chemical reduction processes has been studied by means of Auger electron spectroscopy. Using factor analysis we found that both processes are characterized by the appearance of an intermediate Ti oxidation state, Ti2O3 (Ti3+.

  8. Plasmonic Titanium Nitride Nanostructures via Nitridation of Nanopatterned Titanium Dioxide

    DEFF Research Database (Denmark)

    Guler, Urcan; Zemlyanov, Dmitry; Kim, Jongbum

    2017-01-01

    Plasmonic titanium nitride nanostructures are obtained via nitridation of titanium dioxide. Nanoparticles acquired a cubic shape with sharper edges following the rock-salt crystalline structure of TiN. Lattice constant of the resulting TiN nanoparticles matched well with the tabulated data. Energy...

  9. Studies on the sintering of copper powder compacts

    International Nuclear Information System (INIS)

    Elmasry, M.A.A.; Abadir, M.F.; Mahdy, A.N.; Elkinawy, W.S.

    1995-01-01

    Solid state sintering behavior of cylindrical compacts, (1 cm diameter and 1 cm height), made of copper powder was studied within a range of compacting pressure of 75 up to 300 MPa, sintering temperature of 600 up to to 900 degree C, and sintering time of 5 up to 60 min in a reducing atmosphere composed of H2 and N 2 gases with a volumetric ratio 3:1. The green and the sintered densities were found to to increase with the compacting pressure. Higher sintering temperature, and time favour increased sintered density. probable mechanisms during the initial stage of sintering were disclosed. It was found that low pressures cause dilation of closed pores, and vice versa. At low pressures and temperatures the surface diffusion mechanism is favoured, While high temperatures favour lattice diffusion mechanism. at high pressures, the lattice diffusion mechanism is suppressed while surface diffusion predominates. Density and hence shrinkage were also found to increase with the increase of sintering time, While its rate increases with the increase of sintering temperature. the influence of sintering conditions on the hardness of the compacts was studied. An increase in hardness, When higher compacting pressures and higher sintering temperatures were adopted, has bee obtained. 11 figs

  10. Factors Affecting the Sintering of UO2 Pellets

    International Nuclear Information System (INIS)

    El-Hakim, E.; Afifi, Y.K.

    1999-01-01

    Sintering of UO 2 pellets is affected by many parameters such as; UO 2 powder parameters, the conditions followed for preparing the green UO 2 pellets and the sintering scheme(heating and cooling rate, soaking time and temperature). The aim of this work is to study the effect of some these parameters on the characteristics of the sintered UO 2 pellets were qualified according to the technical specifications of Candu fuel. Pressed green pellets at different pressing force (15 to 50 k N) were sintered at 1650 ±20 degree for two hours to study the effect of pressing force on the sintered pellets characteristics; visual inspection, pellet dimensions, density and shrinkage ratio. Compacted green pellets at a pressing force of 48 k N were sintered at different sintering temperature (1600± 20 degree, 1650 ±20 degree, 1700± 20 degree) for two hours to study the effect of sintering temperature on the sintered pellets characteristics. The effect of the heating rate (200,300 and 400 degree per hour) on the sintered pellets characteristics was also investigated. It was found that the pressing force used to compact the green pellets had an effect on the density of the sintered pellets. Pellets pressed at 15 k N have a density of 10.3 g/cm 3 while, those pressed at 50 k N have a density of 10.6 g/cm 3. It was observed that increasing the heating rate to 400 degree /h lead to cracked pellets

  11. Inversion defects in MgAl2O4 elaborated by pressureless sintering, pressureless sintering plus hot isostatic pressing, and spark plasma sintering

    International Nuclear Information System (INIS)

    Mussi, A.; Granger, G. Bernard; Addad, A.; Benameur, N.; Beclin, F.; Bataille, A.

    2009-01-01

    The distribution of inversion defects of Al was investigated in dense magnesium-aluminate spinel elaborated by pressureless sintering, pressureless sintering plus hot isostatic pressing, and spark plasma sintering. This study was conducted by energy electron loss spectroscopy analyses and more particularly by energy loss near edge structure investigations of the Al-L 2,3 edge. Several aspects are discussed with the purpose of understanding why charged defects dispersal reveals a special configuration.

  12. Sintering studies on iron-carbon-copper compacts

    Directory of Open Access Journals (Sweden)

    Perianayagam Philomen-D-Anand Raj

    2016-01-01

    Full Text Available Sintered Iron-Carbon-Copper parts are among the most widely used powder metallurgy product in automobile. In this paper, studies have been carried out to find out the sintering characteristics of iron-carbon-copper compacts when sintered in nitrogen atmosphere. The effects of various processing parameters on the sintering characteristics were studied. The various processing parameters considered were compaction pressure, green density and sintering temperature. The sintering characteristics determined were sintered density, porosity, dimensional change, micro hardness and radial crush strength. The results obtained have been discussed on the basis of micro structural observations. The characteristics of SEM fractography were also used to determine the mechanism of fracture. The fracture energy is strongly dependent on density of the compact.

  13. In vitro cytotoxicity and surface topography evaluation of additive manufacturing titanium implant materials.

    Science.gov (United States)

    Tuomi, Jukka T; Björkstrand, Roy V; Pernu, Mikael L; Salmi, Mika V J; Huotilainen, Eero I; Wolff, Jan E H; Vallittu, Pekka K; Mäkitie, Antti A

    2017-03-01

    Custom-designed patient-specific implants and reconstruction plates are to date commonly manufactured using two different additive manufacturing (AM) technologies: direct metal laser sintering (DMLS) and electron beam melting (EBM). The purpose of this investigation was to characterize the surface structure and to assess the cytotoxicity of titanium alloys processed using DMLS and EBM technologies as the existing information on these issues is scarce. "Processed" and "polished" DMLS and EBM disks were assessed. Microscopic examination revealed titanium alloy particles and surface flaws on the processed materials. These surface flaws were subsequently removed by polishing. Surface roughness of EBM processed titanium was higher than that of DMLS processed. The cytotoxicity results of the DMLS and EBM discs were compared with a "gold standard" commercially available titanium mandible reconstruction plate. The mean cell viability for all discs was 82.6% (range, 77.4 to 89.7) and 83.3% for the control reconstruction plate. The DMLS and EBM manufactured titanium plates were non-cytotoxic both in "processed" and in "polished" forms.

  14. Porous titanium scaffolds fabricated using a rapid prototyping and powder metallurgy technique.

    Science.gov (United States)

    Ryan, Garrett E; Pandit, Abhay S; Apatsidis, Dimitrios P

    2008-09-01

    One of the main issues in orthopaedic implant design is the fabrication of scaffolds that closely mimic the biomechanical properties of the surrounding bone. This research reports on a multi-stage rapid prototyping technique that was successfully developed to produce porous titanium scaffolds with fully interconnected pore networks and reproducible porosity and pore size. The scaffolds' porous characteristics were governed by a sacrificial wax template, fabricated using a commercial 3D-printer. Powder metallurgy processes were employed to generate the titanium scaffolds by filling around the wax template with titanium slurry. In the attempt to optimise the powder metallurgy technique, variations in slurry concentration, compaction pressure and sintering temperature were investigated. By altering the wax design template, pore sizes ranging from 200 to 400 microm were achieved. Scaffolds with porosities of 66.8 +/- 3.6% revealed compression strengths of 104.4+/-22.5 MPa in the axial direction and 23.5 +/- 9.6 MPa in the transverse direction demonstrating their anisotropic nature. Scaffold topography was characterised using scanning electron microscopy and microcomputed tomography. Three-dimensional reconstruction enabled the main architectural parameters such as pore size, interconnecting porosity, level of anisotropy and level of structural disorder to be determined. The titanium scaffolds were compared to their intended designs, as governed by their sacrificial wax templates. Although discrepancies in architectural parameters existed between the intended and the actual scaffolds, overall the results indicate that the porous titanium scaffolds have the properties to be potentially employed in orthopaedic applications.

  15. Report on electric cars and plug-in hybrid cars; Redegoerelse - elbiler og plug-in hybridbiler

    Energy Technology Data Exchange (ETDEWEB)

    Elkjaer Toennesen, A.; Winther, K.; Noerregaard, K. (Teknologisk Institut, Taastrup (Denmark)); Larsen, Esben; Christensen, Linda; Kveiborg, O. (Danmarks Teknologiske Univ., Kgs. Lyngby (DTU) (Denmark))

    2010-04-15

    The Center for Green Transport at the Danish Transport Authority has prepared this statement in order to uncover driving technical aspects, user expectations and needs, and the environmental consequences of using electric and plug-in hybrid cars. An electric car is defined as a car driven by an electric motor that has a battery that can be charged with power from the grid. A plug-in hybrid car is defined as a car that combines gasoline or diesel engine with an electric motor with a battery which can be recharged with power from the grid. From an overall consideration related to the transport sector electric cars and plug-in hybrid cars have the major advantage that negative impacts on environment and climate from traffic can be reduced while the high mobility is maintained. Through an increased use of electric cars and plug-in hybrid cars, the many advantages attached to the car as an individual transportation form is maintained, while CO{sub 2} emissions etc. are reduced. Electric cars and plug-in hybrid cars is one of the technologies that are considered to have particularly great prospects in the medium term when it comes to promoting new technologies in transport. Another advantage of using electric vehicles is the power supply factor. An increased use of electricity in transport will reduce the need for and dependence on fossil fuels in the sector. Both electric cars and plug-in hybrid cars are expected to be used for storage of wind power, a possibility which is hardly available today. The plug-in hybrid car could meet some of the challenges facing the pure electric car, because it also can use conventional fuel. The report presents analyses based on three focus areas: a) Users' needs, expectations and economics in relation to vehicles; b) The technology - and hence the manufacturers' opportunities and challenges; c) Connection to the power grid. (ln)

  16. The Plug-in Concept: Technology and Aesthetics of Change

    Directory of Open Access Journals (Sweden)

    Peter Šenk

    2013-01-01

    Full Text Available The architecture concept of plug-in is based on the duality of the infrastructure system and units or elements connected to it. In the context of megastructures, the concept was most vividly characterised by works of Archigram and Japanese Metabolists in the 1960s and early 1970s. Blurring the boundary between the building and the city, the plug-in concept outgrew architectural boundaries and was slowly transformed into an urbanistic concept.The paper presents the cultural context relevant to contemporaneity, which influenced specific development of the technology-driven concept of plug-in in the British Archigram Group and Japanese Metabolists. Based on the aesthetics of change and incompleteness, which was characterised by similar architectural manifestations despite entirely different cultural backgrounds, the plug-in concept foreshadowed social transformation based on freedom, individualisation and mobility in an utopian manner and held a promise of urban development with adaptability to unpredictable needs and desires of residents, who would become its co-creators with an active approach.Although the revolutionary sixties are quite some time behind, the plug-in concept in its commodified form has become and remained operational and relevant at least on the metaphorical level; in the contemporary space it is evident primarily in urbanism and not as much in its original architectural form.

  17. RCC Plug Repair Thermal Tools for Shuttle Mission Support

    Science.gov (United States)

    Rodriguez, Alvaro C.; Anderson, Brian P.

    2010-01-01

    A thermal math model for the Space Shuttle Reinforced Carbon-Carbon (RCC) Plug Repair was developed to increase the confidence in the repair entry performance and provide a real-time mission support tool. The thermal response of the plug cover plate, local RCC, and metallic attach hardware can be assessed with this model for any location on the wing leading edge. The geometry and spatial location of the thermal mesh also matches the structural mesh which allows for the direct mapping of temperature loads and computation of the thermoelastic stresses. The thermal model was correlated to a full scale plug repair radiant test. To utilize the thermal model for flight analyses, accurate predictions of protuberance heating were required. Wind tunnel testing was performed at CUBRC to characterize the heat flux in both the radial and angular directions. Due to the complexity of the implementation of the protuberance heating, an intermediate program was developed to output the heating per nodal location for all OML surfaces in SINDA format. Three Design Reference Cases (DRC) were evaluated with the correlated plug thermal math model to bound the environments which the plug repair would potentially be used.

  18. Manitoba plug-in hybrid electric vehicle (PHEV) demonstration

    Energy Technology Data Exchange (ETDEWEB)

    Hoemsen, R. [Red River College, Winnipeg, MB (Canada); Parsons, R. [Government of Manitoba, Winnipeg, MB (Canada). Centre for Emerging Renewable Energy

    2010-07-01

    Manitoba has low electricity rates, the highest proportion of renewables, and a legislated commitment to reduce greenhouse gases. However, the province still relies heavily on oil as everyone else. The mix of energy opportunities in Manitoba were highlighted in this presentation, with particular reference to the commercialization of electric vehicles. Several photographs were presented of the Toyota plug-in hybrid vehicle and a plug-in hybrid electric demonstration vehicle. A demonstration project overview was offered that used technology from A123 Systems Inc. The conversion module and vehicle users were profiled. Topics that were presented related to the demonstration project included monitoring; gasoline fuel economy results; fuel economy variability; cold weather operation; cold weather issues; battery upgrade solutions; and highly qualified personnel. It was concluded that in terms of follow-up, there is a need to combine findings of current plug-in hybrid electric vehicle demonstration with those for the new Toyota production plug-in hybrid vehicles. Key next steps for the demonstration are to address cabin heating requirements; better characterizing winter performance; and implementation of IPLC units on all plug-in hybrid electric vehicles for electricity consumption. figs.

  19. Method for preventing plugging of water wells by clay

    Energy Technology Data Exchange (ETDEWEB)

    Blazhkov, V I

    1966-01-01

    A method is suggested for preventing the plugging of water-bearing sands by clay from drilling fluids. It consists in placing a cement plug in the upper nipple above the filter, in order to prevent its plugging during the installation. The drilling mud passes through the rinsing windows and fills the internal void of the filter column, thus preventing further percolation and plugging of the filter during its lowering. When a 2-filter column is lowered, the clay solution is pumped into the interval between the cement plug and the next filter; this is done gradually in proportion to the addition of new pipes. When the drilling mud level lowers in the annular space between the pipes, the mud cake, together with water-saturated sand, passes through the rinsing windows into the pipes and is removed to the surface by airlift or other methods. This procedure is described in detail, discussed for various conditions of well structure, and illustrated by schematic drawings. Its advantage is in the possibility of separate testing and production of all water-bearing zones in the well, and it does not require the use of pure water for well washing.

  20. Design approaches for access plugs in a basalt repository

    International Nuclear Information System (INIS)

    O'Rourke, J.; Allirot, D.; O'Connor, K.

    1982-01-01

    This paper describes research, laboratory testing, and analytical approaches taken toward the development of designs for sealing boreholes, shafts, and tunnels penetrating from ground surface to a deep, mined nuclear waste repository in basalt. A material selection process leading to identification of preferred sealing materials is discussed, and the laboratory testing program to define the geochemical and geotechnical performance of these materials is described. Analysis of the environmental conditions in the Columbia Plateau basalt flows leads to identification of tentative design criteria for plug systems. These design criteria include performance of the plug as a hydraulic barrier and as a radionuclide barrier. An important problem for effective performance of a plug system as a hydraulic barrier is shown to be a potentially disturbed zone surrounding the excavation in the stressed and jointed host rock. An idealized one-dimensional numerical model is described for analyzing the performance of the plug as a barrier to radionuclide transport. The preliminary analyses led to the conclusion that the composition and dimensions of practical candidate plugs can satisfy both hydraulic and radionuclide barrier criteria. Examples of candidate designs are shown for boreholes, shafts, and tunnels. 9 references, 6 figures, 6 tables

  1. Plug-in electric vehicles integrating fluctuating renewable electricity

    Energy Technology Data Exchange (ETDEWEB)

    Dallinger, David

    2013-11-01

    This paper examines a method to model plug-in electric vehicles as part of the power system and presents results for the contribution of plug-in electric vehicles to balance the fluctuating electricity generation of renewable energy sources. The scientific contribution includes: - A novel approach to characterizing fluctuating generation. This allows the detailed comparison of results from energy analysis and is the basis to describe the effect of electricity from renewable energy sources and plug-in electric vehicles on the power system. - The characterization of mobile storage, which includes the description of mobility behavior using probabilities and battery discharging costs. - The introduction of an agent-based simulation approach, coupling energy markets and distributed grids using a price-based mechanism design. - The description of an agent with specific driving behavior, battery discharging costs and optimization algorithm suitable for real plug-in vehicles and simulation models. - A case study for a 2030 scenario describing the contribution of plug-in electric vehicles to balance generation from renewable energy sources in California and Germany.

  2. Coating of the orthopaedic titanium alloys with sol-gel derived hydroxyapatite

    International Nuclear Information System (INIS)

    Milev, A.; Green, D.; Chai, C.S.; Ben-Nissan, B.

    1999-01-01

    Hydroxyapatite (HAp) is known to be both biocompatible and bioactive material, however, due to its poor mechanical properties and design limitations is not suitable for applying as a load bearing implant. This could be overcome by using appropriate metallic substrates covered with HAp, derived via different techniques. These coatings allow improved adhesion strength of the load bearing substrate to the bone, resulting in shorter healing periods as well as predictable behaviour of the implant for longer periods of time. There are different techniques of producing HAp appropriate for coating purposes. Due to the small particle size of the grains derived, sol-gel route is preferable where lower sintering temperatures are of primary importance. For better adhesion between substrate and hydroxyapatite coating, the surface of titanium substrate, in this study, was converted to titanium nitride and/or oxynitride. Sintering temperatures of 900 deg C have been used for producing crystalline HAp coatings. The control of sol-gel solutions and the analysis of the coatings were carried out using XRD, SEM and DTA techniques. Results obtained indicate high quality HAp coatings can be produced on titanium substrates especially with complex shapes that benefits over the other coating methods

  3. Corrosion of Ti6Al4V pins produced by direct metal laser sintering

    Science.gov (United States)

    de Damborenea, J. J.; Arenas, M. A.; Larosa, Maria Aparecida; Jardini, André Luiz; de Carvalho Zavaglia, Cecília Amélia; Conde, A.

    2017-01-01

    Direct Metal Laser Sintering (DMLS) technique allows the manufacturing a wide variety of medical devices for any type of prosthetic surgery (HIP, dental, cranial, maxillofacial) as well as for internal fixation devices (K-Wires or Steinmann Pins). There are a large number of research studies on DMLS, including microstructural characterization, mechanical properties and those based on production quality assurance but the influence of porosity in the corrosion behavior of these materials not been sufficiently considered. In the present paper, surgical pins of Ti6Al4V have been produced by DMLS. After testing in a phosphate buffered saline solution, the surface of the titanium alloy appeared locally covered by a voluminous white oxide. This unexpected behavior was presumably due to the existence of internal defects in the pins as result of the manufacturing process. The importance of these defects-that might act as crevice nucleation sites- has been revealed by electrochemical techniques and confirmed by computed tomography.

  4. Physical metallurgy of titanium alloys

    International Nuclear Information System (INIS)

    Collings, E.W.

    1988-01-01

    Researches in electric, magnetic, thermophysical properties of titanium alloys in the wide range of temperatures (from helium upto elevated one), as well as stability of phases in alloys of different types are generalized. Fundamental description of physical properties of binary model alloys is given. Acoustic emission, shape memory and Bauschinger effects, pseudoelasticity, aging and other aspects of physical metallurgy of titanium alloys are considered

  5. Interaction of clay and concrete plugs - Plugging of 5 m deep hole KA1621G01 at Aespoe

    Energy Technology Data Exchange (ETDEWEB)

    Pusch, Roland [Drawrite AB, Lund (Sweden); Luleaa Technical Univ., Luleaa (Sweden); Ramqvist, Gunnar [Eltekno AB, Figeholm (Sweden)

    2011-11-15

    Sealing of deep boreholes in repository rock is planned to be made by installing dense smectite clay plugs where the rock is low-permeable and casting concrete where the holes intersect water-bearing fracture zones. Such zones have to be stabilized before sealing starts because fragments of rock can otherwise fall off and make it difficult to bring equipment for concrete casting and clay plug units down. These parts of the holes are filled with concrete and clay plugs are then inserted up to the nearest fracture zone where concrete is filled to the required level etc. The role of the concrete in the hole and in the closest part of the surrounding fracture zone is to provide stable parts that are sufficiently fine-porous to prevent clay particles from contacting clay plugs to migrate into the fractures and be lost by erosion. While the larger parts of long clay plugs are believed to stay largely intact chemically for hundreds of thousands of years, the parts adjacent to concrete plugs may undergo changes and so can the concrete plugs themselves. The objective of the presently reported project was to identify the detailed processes and quantify associated changes in physical properties by investigating samples of clay and concrete from a 2.5 m long plug of clay over which an equally long concrete plug had been cast and left to rest for 3 years. The outcome of the investigations was that significant chemically induced changes in mineralogy and physical performance had occurred within a few centimetres distance from the clay/concrete contact but that virtually no changes had taken place at larger distance. A comprehensive laboratory study including X-ray diffraction (XRD), X-ray fluorescence (XRF) and electron microscopy study (SEM and TEM) on the sample material was performed including also dual beam (combined ion and electron) microscopy. It was found that the clay had infiltrated the contacting concrete plug after filling of the borehole since clay was detected both

  6. Interaction of clay and concrete plugs - Plugging of 5 m deep hole KA1621G01 at Aespoe

    International Nuclear Information System (INIS)

    Pusch, Roland; Ramqvist, Gunnar

    2011-11-01

    Sealing of deep boreholes in repository rock is planned to be made by installing dense smectite clay plugs where the rock is low-permeable and casting concrete where the holes intersect water-bearing fracture zones. Such zones have to be stabilized before sealing starts because fragments of rock can otherwise fall off and make it difficult to bring equipment for concrete casting and clay plug units down. These parts of the holes are filled with concrete and clay plugs are then inserted up to the nearest fracture zone where concrete is filled to the required level etc. The role of the concrete in the hole and in the closest part of the surrounding fracture zone is to provide stable parts that are sufficiently fine-porous to prevent clay particles from contacting clay plugs to migrate into the fractures and be lost by erosion. While the larger parts of long clay plugs are believed to stay largely intact chemically for hundreds of thousands of years, the parts adjacent to concrete plugs may undergo changes and so can the concrete plugs themselves. The objective of the presently reported project was to identify the detailed processes and quantify associated changes in physical properties by investigating samples of clay and concrete from a 2.5 m long plug of clay over which an equally long concrete plug had been cast and left to rest for 3 years. The outcome of the investigations was that significant chemically induced changes in mineralogy and physical performance had occurred within a few centimetres distance from the clay/concrete contact but that virtually no changes had taken place at larger distance. A comprehensive laboratory study including X-ray diffraction (XRD), X-ray fluorescence (XRF) and electron microscopy study (SEM and TEM) on the sample material was performed including also dual beam (combined ion and electron) microscopy. It was found that the clay had infiltrated the contacting concrete plug after filling of the borehole since clay was detected both

  7. Device for sealing a rotating plug in a nuclear reactor

    International Nuclear Information System (INIS)

    Brandstetter, R.

    1975-01-01

    The invention relates to the sealing of a rotating plug in a nuclear reactor. The sealing arrangement comprises a friction track which is formed along the periphery of the top of a ring mounted on a stationary element. An annular base coaxial with the plug is secured in sealing-tight manner to the stationary bearing around the ring and the track by means of a seal which rests on the annular base and also on the friction track of the ring and which comprises at least one friction ring and a clamping spring ring. The seal is clamped against the friction track to retractable clamping means when the plug is stationary, the retractable clamping means being carried by a ring secured to the first-mentioned ring. (U.S.)

  8. Revascularization and Apical Plug in an Immature Molar

    Science.gov (United States)

    Roghanizadeh, Leyla; Fazlyab, Mahta

    2018-01-01

    Managing of necrotic permanent teeth with immature apices is a treatment challenges. Treatment of such teeth includes apexification, apical plug and more recently, revascularization technique with the probable advantage of continuation of root development. In the present case report the referred patient had discomfort with a necrotic immature mandibular first molar. Periapical radiography showed a rather large apical lesion around immature roots. Revascularization protocol using calcium-enriched mixture (CEM) cement was indicated for the mesial root. However, in distal canal apical plug technique was applied. At 2-year follow-up, both procedures were successful in relieving patient’s symptoms. Dentin formation and increase in length of the mesial root was obvious. Apical plug and revascularization technique proved to be successful in management of necrotic immature teeth; moreover, revascularization carried the advantage of continuation of root development. PMID:29692851

  9. Flexible Plug Repair for Shuttle Wing Leading Edge

    Science.gov (United States)

    Camarda, Charles J.; Sikora, Joseph; Smith, Russel; Rivers, H.; Scotti, Stephen J.; Fuller, Alan M.; Klacka, Robert; Reinders, Martin; Schwind, Francis; Sullivan, Brian; hide

    2012-01-01

    In response to the Columbia Accident Investigation Board report, a plug repair kit has been developed to enable astronauts to repair the space shuttle's wing leading edge (WLE) during orbit. The plug repair kit consists of several 17.78- cm-diameter carbon/silicon carbide (C/SiC) cover plates of various curvatures that can be attached to the refractory carbon-carbon WLE panels using a TZM refractory metal attach mechanism. The attach mechanism is inserted through the damage in the WLE panel and, as it is tightened, the cover plate flexes to conform to the curvature of the WLE panel within 0.050 mm. An astronaut installs the repair during an extravehicular activity (EVA). After installing the plug repair, edge gaps are checked and the perimeter of the repair is sealed using a proprietary material, developed to fill cracks and small holes in the WLE.

  10. Structural integrity investigations of feeder pipe ice plugging procedures

    International Nuclear Information System (INIS)

    Flaman, M.T.; Shah, N.N.

    1985-03-01

    A procedure involving the use of a liquid nitrogen cooled heat exchanger to form internal ice plugs in feeder pipes is routinely used in nuclear generating stations. The use of this procedure has caused concerns with regard to the safety of station maintenance personnel, and in regard to the integrity of the feeder pipes. This report describes the results of laboratory stress and pressure measurements which were performed on a feeder pipe section during ice plugging operations to investigate these concerns. From the results of this study, and from the results of previous studies of material behaviour at low temperatures, it has been determined that the ice plugging procedure can be performed on feeder pipes in a safe and effective manner

  11. Titanium for salt water service

    International Nuclear Information System (INIS)

    Gadiyar, H.S.; Shibad, P.R.

    1980-01-01

    Titanium has potential as major material of construction in desalination plants, in condensers and heat exchangers, in view of its excellent corrosion resistance to salt water upto at least 120deg C. The advantages of titanium in such applications are brought out. The various specific problems such as pitting, crevice and galvanic corrosion and the preventive methods, for adopting titanium have been discussed. The hydriding problem can be overcome by suitably controlling the operating parameters such as temperature and surface preparation. A case has been made to prove the economic viability of titanium in comparison to Al-brass and Cu-Ni alloy. The future of titanium seems to be very promising in view of the negligible tube failures and outages. (auth.)

  12. Osseointegration improvement by shot peening in titanium dental implants

    International Nuclear Information System (INIS)

    Aparicio, C.; Gil, F.J.; Planell, J.A.; Padros, A.; Peraire, C.

    1998-01-01

    In order to optimize the implant-bone fixation, different shot peening treatments with different shot particles (TiO 2 , Al 2 O 3 ; SiC) have been made. The influence that each type of shot particle has in the bone colonization on the different treatment surfaces has been determined by means of osteoblast-like cells culture. Commercially pure titanium discs have been shot peened. Their qualitative and quantitative surface roughness have been characterized; as well as their surface contamination caused by the shot particles. Particle size has also been determined, before and after the treatment, in order to evaluate their breaking averages. Finally, a TiO 2 shot particles manufacture process by sintering has been developed. The manufacture has been necessary since this type of shot particles are not available in the market with the adequate size. (Author) 10 refs

  13. Plug and Play PV Systems for American Homes

    Energy Technology Data Exchange (ETDEWEB)

    Hoepfner, Christian [Fraunhofer USA, Inc., Boston, MA (United States)

    2016-12-22

    The core objectives of the Plug & Play PV Systems Project were to develop a PV system that can be installed on a residential rooftop for less than $1.50/W in 2020, and in less than 10 hours (from point of purchase to commissioning). The Fraunhofer CSE team’s approach to this challenge involved a holistic approach to system design – hardware and software – that make Plug & Play PV systems: • Quick, easy, and safe to install • Easy to demonstrate as code compliant • Permitted, inspected, and interconnected via an electronic process Throughout the three years of work during this Department of Energy SunShot funded project, the team engaged in a substantive way with inspectional services departments and utilities, manufacturers, installers, and distributors. We received iterative feedback on the system design and on ideas for how such systems can be commercialized. This ultimately led us to conceiving of Plug & Play PV Systems as a framework, with a variety of components compatible with the Plug & Play PV approach, including string or microinverters, conventional modules or emerging lightweight modules. The framework enables a broad group of manufacturers to participate in taking Plug & Play PV Systems to market, and increases the market size for such systems. Key aspects of the development effort centered on the system hardware and associated engineering work, the development of a Plug & Play PV Server to enable the electronic permitting, inspection and interconnection process, understanding the details of code compliance and, on occasion, supporting applications for modifications to the code to allow lightweight modules, for example. We have published a number of papers on our testing and assessment of novel technologies (e.g., adhered lightweight modules) and on the electronic architecture.

  14. Experimental and numerical modeling of sulfur plugging in carbonate reservoirs

    Energy Technology Data Exchange (ETDEWEB)

    Abou-Kassem, J.H. [Chemical and Petroleum Engineering Department, UAE University, PO Box 17555, Al-Ain (United Arab Emirates)

    2000-05-01

    Sour gas, mainly in the form of hydrogen sulfide, is produced in large amounts from many oil and gas reservoirs in the United Arab Emirates. In addition to creating problems in production lines, the precipitation of elemental sulfur in vicinity of the wellbore is often reported to cause wellbore damage. While there have been several studies performed on the role of solid deposition in gas reservoirs, the role of sulfur deposition in oil reservoirs has not been investigated. This paper presents experimental results along with a comprehensive wellbore model that predicts sulfur precipitation as well as plugging. Two separate sets of experiments, one for a gas phase system and another for a crude oil system, were conducted to investigate the deposition of elemental sulfur in (linear) carbonate cores. The gas flow tests were conducted with elemental sulfur being carried with nitrogen through limestone cores. Changes in gas flow rate were monitored while the injection pressure was held constant. A series of experiments generated valuable data for plugging with elemental sulfur. X-ray diffraction tests provided evidence of sulfur deposition along the cores. The oil flow tests were carried out to observe sulfur precipitation and plugging in a carbonate core. The crude oil was de-asphalted before conducting these tests in order to isolate the effect of asphaltene plugging. Significant plugging was observed and was found to be dependent on flow rate and initial sulfur concentration. This information was used in a phenomenological model that was incorporated in the wellbore numerical model. The data for the numerical model were obtained from both test tube and oil flow experiments. By using a phenomenological model, the wellbore plugging was modeled with an excellent match (with experimental results)

  15. MFTF-α+T end plug magnet design

    International Nuclear Information System (INIS)

    Srivastava, V.C.; O'Toole, J.A.

    1983-01-01

    The conceptual design of the end-plug magnets for MFTF-α+T is described. MFTF-α+ T is a near-term upgrade of MFTF-B, which features new end plugs to improve performance. The Fusion Engineering Design Center has performed the engineering design of MFTF-α+T under the overall direction of Lawrence Livermore National Laboratory. Each end plug consists of two Yin-Yang pairs, each with approx.2.5:1 mirror ratio and approx.5-T peak field on axis; two transition coils; and a recircularizing solenoid. This paper describes the end-plug magnet system functional requirements and presents a conceptual design that meets them. The peak field at the windings of the end-plug coils is approx.6-T. These coils are designed using the NbTi MFTF-B conductor and cooled by a 4.2K liquid helium bath. All the end-plug magnets are designed to operate in the cryostable mode with adequate quench protection for safety. Shielding requirements are stated and a summary of heat loads is provided. Field and force calculations are discussed. The field on axis is shown to meet the functional requirements. Force resultants are reported in terms of winding running loads and resultant coil forces are also given. The magnet structural support is described. A trade study to determine the optimum end-cell coil internal nuclear shield thickness and the resulting coil size based on minimizing the end-cell life cycle cost is summarized

  16. Versatile Friction Stir Welding/Friction Plug Welding System

    Science.gov (United States)

    Carter, Robert

    2006-01-01

    A proposed system of tooling, machinery, and control equipment would be capable of performing any of several friction stir welding (FSW) and friction plug welding (FPW) operations. These operations would include the following: Basic FSW; FSW with automated manipulation of the length of the pin tool in real time [the so-called auto-adjustable pin-tool (APT) capability]; Self-reacting FSW (SRFSW); SR-FSW with APT capability and/or real-time adjustment of the distance between the front and back shoulders; and Friction plug welding (FPW) [more specifically, friction push plug welding] or friction pull plug welding (FPPW) to close out the keyhole of, or to repair, an FSW or SR-FSW weld. Prior FSW and FPW systems have been capable of performing one or two of these operations, but none has thus far been capable of performing all of them. The proposed system would include a common tool that would have APT capability for both basic FSW and SR-FSW. Such a tool was described in Tool for Two Types of Friction Stir Welding (MFS- 31647-1), NASA Tech Briefs, Vol. 30, No. 10 (October 2006), page 70. Going beyond what was reported in the cited previous article, the common tool could be used in conjunction with a plug welding head to perform FPW or FPPW. Alternatively, the plug welding head could be integrated, along with the common tool, into a FSW head that would be capable of all of the aforementioned FSW and FPW operations. Any FSW or FPW operation could be performed under any combination of position and/or force control.

  17. Plug the socket of the main closing valve in a nuclear power plant

    International Nuclear Information System (INIS)

    Neupauer, J.; Bednar, B.

    1988-01-01

    The plug is designed for closing the main closing valve socket during a refuelling shutdown of a nuclear power plant. The plug is fixed in the using jaws forced against the socket ring part. The socket is sealed by expanding a ring between two cone trays. A valve provided in the plug allows draining the pipe. The plug is inserted in the socket using a jib suspended on a rail. Following sealing both sockets the inner surfaces of the closing valve can be decontaminated. Following decontamination, a water-proof cover is slid over the plug protecting the plug moving mechanism from damage. (J.B.). 1 fig

  18. 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

  19. Production of sintered porous metal fluoride pellets

    Science.gov (United States)

    Anderson, L.W.; Stephenson, M.J.

    1973-12-25

    Porous pellets characterized by a moderately reactive crust and a softer core of higher reactivity are produced by forming agglomerates containing a metal fluoride powder and a selected amount ofwater. The metal fluoride is selected to be sinterable and essentially non-reactive with gaseous fluorinating agents. The agglomerates are contacted with a gaseous fluorinating agent under controlled conditions whereby the heat generated by localized reaction of the agent and water is limited to values effccting bonding by localized sintering. Porous pellets composed of cryolite (Na/sub 3/AlF/sub 6/) can be used to selectively remove trace quantities of niobium pentafluoride from a feed gas consisting predominantly of uranium hexafluoride. (Official Gazette)

  20. 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...... 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...... 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...

  1. Warning: safety risk with some Apple AC Wall Plug Adapters

    CERN Multimedia

    CERN IT department

    2016-01-01

    Dear Mac and iOS Users, Apple has determined that some of its two prong Apple AC wall plug adapters may break and create a risk of electrical shock.   CERN users can now exchange their affected Apple wall plug adapters at the Service Desk. To find out if your adapter is affected and for any further information concerning the procedure to follow to exchange it, please check the following URL: https://cern.service-now.com/service-portal/view-outage.do?n=OTG0028639.

  2. The dimensional accuracy of the sintered billets

    Directory of Open Access Journals (Sweden)

    Чингиз Ариф оглы Алиев

    2016-01-01

    Full Text Available The article presents the results of assessing the impact of the behaviour stability of the components included in the compositions and process parameters of their production, on the dimensional accuracy of workpieces. It was found that by increasing the amount of oxide in the composition is greater compaction of the sintered billet in the process of heat treatment. This also increases the density of all components of the composition

  3. Spark plasma sintering of tantalum carbide

    International Nuclear Information System (INIS)

    Khaleghi, Evan; Lin, Yen-Shan; Meyers, Marc A.; Olevsky, Eugene A.

    2010-01-01

    A tantalum carbide powder was consolidated by spark plasma sintering. The specimens were processed under various temperature and pressure conditions and characterized in terms of relative density, grain size, rupture strength and hardness. The results are compared to hot pressing conducted under similar settings. It is shown that high densification is accompanied by substantial grain growth. Carbon nanotubes were added to mitigate grain growth; however, while increasing specimens' rupture strength and final density, they had little effect on grain growth.

  4. Thermal Stability of Silver Paste Sintering on Coated Copper and Aluminum Substrates

    Science.gov (United States)

    Pei, Chun; Chen, Chuantong; Suganuma, Katsuaki; Fu, Guicui

    2018-01-01

    The thermal stability of silver (Ag) paste sintering on coated copper (Cu) and aluminum (Al) substrates has been investigated. Instead of conventional zincating or nickel plating, magnetron sputtering was used to achieve coating with titanium (Ti) and Ag. Silicon (Si) chips were bonded to coated Cu and Al substrates using a mixture of submicron Ag flakes and particles under 250°C and 0.4 MPa for 30 min. The joints were then subject to aging testing at 250°C for duration of 200 h, 500 h, and 1000 h. Two types of joints exhibited satisfactory initial shear strength above 45 MPa. However, the shear strength of the joints on Al substrate decreased to 28 MPa after 1000 h of aging, while no shear strength decline was detected for the joints on Cu substrate. Fracture surface analysis revealed that the vulnerable points of the two types of joints were (1) the Ag layer and (2) the interface between the Ti layer and Cu substrate. Based on the results of scanning electron microscopy (SEM), energy-dispersive x-ray spectroscopy (EDS), and simulations, cracks in the Ag layer were identified as the cause of the shear strength degradation in the joints on Al substrate. The interface evolution of the joints on Cu substrate was ascribed to Cu migration and discontinuity points that initialized in the Ti layer. This study reveals that Al exhibited superior thermal stability with sintered Ag paste.

  5. Low modulus and bioactive Ti/α-TCP/Ti-mesh composite prepared by spark plasma sintering.

    Science.gov (United States)

    Guo, Yu; Tan, Yanni; Liu, Yong; Liu, Shifeng; Zhou, Rui; Tang, Hanchun

    2017-11-01

    A titanium mesh scaffold composite filled with Ti/α-TCP particles was prepared by spark plasma sintering (SPS). The microstructures and interfacial reactions of the composites were investigated by scanning electron microscopy (SEM), Energy Dispersive Spectroscopy (EDS) and X-ray diffraction (XRD) analyses. The compressive strength and elastic modulus were also measured. In vitro bioactivity and biocompatibility was evaluated by using simulated body fluid and cells culture, respectively. After high temperature sintering, Ti oxides, Ti x P y and CaTiO 3 were formed. The formation of Ti oxides and Ti x P y were resulted from the diffusion of O and P elements from α-TCP to Ti. CaTiO 3 was the reaction product of Ti and α-TCP. The composite of 70Ti/α-TCP incorporated with Ti mesh showed a high compressive strength of 589MPa and a low compressive modulus of 30GPa. The bioactivity test showed the formation of a thick apatite layer on the composite and well-spread cells attachment. A good combination of mechanical properties and bioactivity indicated a high potential application of Ti/α-TCP/Ti-mesh composite for orthopedic implants. Copyright © 2017. Published by Elsevier B.V.

  6. Thermoelectric Coolers with Sintered Silver Interconnects

    Science.gov (United States)

    Kähler, Julian; Stranz, Andrej; Waag, Andreas; Peiner, Erwin

    2014-06-01

    The fabrication and performance of a sintered Peltier cooler (SPC) based on bismuth telluride with sintered silver interconnects are described. Miniature SPC modules with a footprint of 20 mm2 were assembled using pick-and-place pressure-assisted silver sintering at low pressure (5.5 N/mm2) and moderate temperature (250°C to 270°C). A modified flip-chip bonder combined with screen/stencil printing for paste transfer was used for the pick-and-place process, enabling high positioning accuracy, easy handling of the tiny bismuth telluride pellets, and immediate visual process control. A specific contact resistance of (1.4 ± 0.1) × 10-5 Ω cm2 was found, which is in the range of values reported for high-temperature solder interconnects of bismuth telluride pellets. The realized SPCs were evaluated from room temperature to 300°C, considerably outperforming the operating temperature range of standard commercial Peltier coolers. Temperature cycling capability was investigated from 100°C to 235°C over more than 200 h, i.e., 850 cycles, during which no degradation of module resistance or cooling performance occurred.

  7. Sintered stabilized zirconia microstructure and conductivity

    International Nuclear Information System (INIS)

    Bernard, Herve.

    1981-04-01

    The elaboration of a stabilized zirconia powder which sinters at 1300 0 C and the influence of the sintered polycristal microstructure on its ionic conductivity have been studied. Among three investigated powder preparation processes, coprecipitation in an ammoniacal solution was chosen. After sintering at 1300 0 C, the pellet density was higher than 93% of the theoretical density. It even approached up to 98% TD with addition of less than 0,5 mole % Al 2 O 3 to the initial powder. The overall electrolyte conductivity and the inter and intragranular contributions have been determined by complex impedance spectroscopy. ZrO 2 -Y 2 O 3 solid solution conductivity was scarcely improved by Y 2 O 3 exchange with Yb 2 O 3 or Gd 2 O 3 . This conductivity greatly increases with grain size, its improvement with decreasing porosity, which has been quantified, is less sensible. Moreover, two original properties were noticed: small amounts of Al 2 O 3 and quenching greatly enhanced the overall conductivity. At temperatures below 500 0 C, grain boundaries only insured a partial migration of conductive ions. A parallel type electrical equivalent circuit suited well with this blocking effect [fr

  8. Influence of alloying elements and density on aqueous corrosion behaviour of some sintered low alloy steels

    International Nuclear Information System (INIS)

    Kandavel, T.K.; Chandramouli, R.; Karthikeyan, P.

    2012-01-01

    Highlights: ► Corrosion of low alloy P/M steels under HCl acid pickling environment has been studied. ► Influence of density, strain and alloying elements on the rate of corrosion of the steels has been investigated. ► Residual porosity has significant effect on acid corrosion. ► Addition of the alloying elements Cu, Mo and Ti reduces the corrosion rate significantly. ► Carbide forming elements Mo and Ti improve further the resistance of the steels to aqueous corrosion. -- Abstract: Low alloy steels produced through powder metallurgy route of sintering followed by forging are promising candidate materials for high strength small components. Porosity in such steels poses a real challenge during acid pickling treatment, which is one of the processing steps during manufacturing. The present research work attempts to investigate the mechanism underlying the acid corrosion behaviour of some sintered low alloy steels under induced acid pickling conditions. Sintered-forged low alloy steel samples containing molybdenum (Mo), copper (Cu) and titanium (Ti) were subjected to aqueous corrosion attack by immersing the samples in 18% HCl (Hydrochloric acid) solution for 25 h. Sample weight loss and Fe (Iron) loss were estimated for the corroded samples. The morphology of the corroded surfaces was studied through metallography and scanning electron microscopy. Higher porosity alloys underwent enhanced corrosion rates. Both corrosion rate and iron loss are found to decrease linearly with reduction in porosity in all cases of the alloys. The alloying elements Mo, Ti and Cu, when added in combination, have played a complementary role in the reduction of corrosion rate by almost one order of magnitude compared to unalloyed steel. Presence of carbides of the carbide forming elements Mo and Ti played a positive role on the corrosion behaviour of the low alloy steels.

  9. Electrophoretic deposition of magnesium silicates on titanium implants: Ion migration and silicide interfaces

    Energy Technology Data Exchange (ETDEWEB)

    Afshar-Mohajer, M. [Center for Advanced Manufacturing and Material Processing, Department of Mechanical Engineering, Faculty of Engineering, University of Malaya, Kuala Lumpur 50603 (Malaysia); Yaghoubi, A., E-mail: yaghoubi@siswa.um.edu.my [Center for High Impact Research, University of Malaya, Kuala Lumpur 50603 (Malaysia); Ramesh, S., E-mail: ramesh79@um.edu.my [Center for Advanced Manufacturing and Material Processing, Department of Mechanical Engineering, Faculty of Engineering, University of Malaya, Kuala Lumpur 50603 (Malaysia); Bushroa, A.R.; Chin, K.M.C.; Tin, C.C. [Center for Advanced Manufacturing and Material Processing, Department of Mechanical Engineering, Faculty of Engineering, University of Malaya, Kuala Lumpur 50603 (Malaysia); Chiu, W.S. [Low Dimensional Materials Research Center, Department of Physics, University of Malaya, Kuala Lumpur 50603 (Malaysia)

    2014-07-01

    Magnesium silicates (Mg{sub x}SiO{sub y}) and in particular forsterite (Mg{sub 2}SiO{sub 4}) owing to their low thermal expansion mismatch with metals are promising materials for bioactive coating of implants. Here, we report the electrophoretic deposition (EPD) of forsterite onto titanium substrates using different precursors. Unlike bulk samples which achieve full stoichiometry only beyond 1400 °C, non-stoichiometric magnesium silicate rapidly decomposes into magnesium oxide nanowires during sintering. Elemental mapping and X-ray diffraction suggest that oxygen diffusion followed by ion exchange near the substrate leads to formation of an interfacial Ti{sub 5}Si{sub 3} layer. Pre-annealed forsterite powder on the other hand shows a comparatively lower diffusion rate. Overall, magnesium silicate coatings do not exhibit thermally induced microcracks upon sintering as opposed to calcium phosphate bioceramics which are currently in use.

  10. A Novel Porous Diamond - Titanium Biomaterial: Structure, Microstructure, Physico-Mechanical Properties and Biocompatibility

    Directory of Open Access Journals (Sweden)

    ZULMIRA A.S. GUIMARÃES

    2017-12-01

    Full Text Available ABSTRACT With the aim of introducing permanent prostheses with main properties equivalent to cortical human bone, Ti-diamond composites were processed through powder metallurgy. Grade 1 titanium and mixtures of Ti powder with 2%, 5% and 10 wt% diamond were compacted at 100MPa, and then sintered at 1250°C/2hr/10-6mbar. Sintered samples were studied in the point of view of their microstructures, structures, yield strength and elastic modulus. The results showed that the best addition of diamonds was 2 wt%, which led to a uniform porosity, yield strength of 370MPa and elastic modulus of 13.9 GPa. Samples of Ti and Ti-2% diamond were subjected to in vitro cytotoxicity test, using cultures of VERO cells, and it resulted in a biocompatible and nontoxic composite material.

  11. Formation and quantification of calcium titanate with the perovskite structure from alternative sources of titanium

    International Nuclear Information System (INIS)

    Gralik, G.; Raupp-Pereira, F.; Hotza, D.; Labrincha, J.A.; Zanelli, C.; Dondi, M.

    2014-01-01

    This study aimed to evaluate and quantify the formation of calcium titanate (CaTiO3) with perovskite structure from alternative sources of titanium (rutile, ilmenite). Commercial raw materials of the high purity were also characterized as reference. With base in the characterization by X-ray fluorescence of the mineral springs different compositions were formulated and subsequently sintered for 2 h in resistive furnace at temperatures in the range 1000 to 1400°C. After thermal processing the samples were analyzed by X-ray diffraction and the quantification of phases formed by the Rietveld method obtained. The results show that the formation and the amount of calcium titanate minerals from alternative sources depend on factors related to stages of sintering and impurities. The microstructures of the compositions were analyzed by SEM/EDS and bulk density also measured. (author)

  12. Synthesis and characterization on titanium dioxide prepared by precipitation and hydrothermal treatment

    International Nuclear Information System (INIS)

    Santos, Andre V.P. dos; Yoshito, Walter K.; Lazar, Dolores R.R.; Ussui, Valter

    2012-01-01

    Surface properties of titanium dioxide (titania) are outstanding among ceramic materials and enables uses as catalysts, photoelectrochemical devices, solar cells and others. In many of these applications, it is necessary to keep the anatase phase, that is stable only in low temperatures (<400 deg C). In the present work, the influence of hydrothermal treatment on physical characteristics and crystal structure of titania powders synthesized by precipitation was investigated. Characterizations of obtained powders were carried out by X-ray diffraction, surface area analysis by N2 gas sorption (BET) and microstructure of powders and ceramics were analyzed by scanning electron microscopy. As prepared powders were formed as cylindrical pellets by uniaxial pressing and sintered at 1500 deg C for 01 hour. Results showed that anatase phase without formation of rutile phase can be formed in hydrothermally treated samples . Rutile phase is predominant in calcined and/or sintered samples (author)

  13. Microstructural and Mechanical Properties of Porous 60NiTi Prepared by Conventional Press-and-sinter Method

    Directory of Open Access Journals (Sweden)

    Khanlari Khashayar

    2017-01-01

    Full Text Available An intermetallic nickel-titanium alloy, 60NiTi, comprised of approximately 60 wt.% Ni and 40 wt.% Ti, contains a broad combination of physical and mechanical properties such as high hardness, low elastic modulus, resistance to aqueous corrosion and good biocompatibility. These unique combinations make this alloy an attractive candidate for medical components such as implants and prosthesis, where biocompatible materials with high hardness and low stiffness are typically used. The conventional press-and-sinter method which represents the least complex, most flexible and economic powder metallurgy method was used to produce porous 60NiTi parts suitable for biomedical applications. The effect of sintering holding time on the microstructure and mechanical properties is investigated. The structure of the as sintered parts is quite porous which is beneficial based on the medical point of view. The ultimate compressive strength of the samples is higher than that of the compact human bone and can, therefore, meet the strength demand of implants for general bone replacement applications.

  14. Effect of compacting pressure, powder degassing and thermobaric treatment on densification and properties of nanocrystalline titanium nitride

    Directory of Open Access Journals (Sweden)

    Andrei V. Kapylou

    2009-09-01

    Full Text Available The effects of compacting pressure, powder degassing and high pressure sintering temperature and time on the densification and properties of nanocrystalline titanium nitride have been investigated. For this reason, TiN powder with a mean particle size of 55 nm was pressed in the range of compacting pressure from 0.2 to 1.0 GPa and sintered under static pressure of 3.5 GPa in the temperature range of 900–1600°C for 45–120 s. Some of green bodies were degassed in vacuum before sintering. It was shown that samples compacted in the pressure range of 0.2–0.6 GPa have the highest density after the thermobaric treatment. The maximum density (about 97.3 %TD was obtained with degassed samples. Microhardness and microstructure investigations have shown that recrystallization of the TiN nanopowder begins at the sintering temperatures of 1100–1200°C and sintering time less than one minute. The maximum microhardness obtained was 23.2±1.0 GPa and themaximum Young modulus was 370 GPa.

  15. Biomechanical behavior of bone scaffolds made of additive manufactured tricalciumphosphate and titanium alloy under different loading conditions.

    Science.gov (United States)

    Wieding, Jan; Fritsche, Andreas; Heinl, Peter; Körner, Carolin; Cornelsen, Matthias; Seitz, Hermann; Mittelmeier, Wolfram; Bader, Rainer

    2013-12-16

    The repair of large segmental bone defects caused by fracture, tumor or infection remains challenging in orthopedic surgery. The capability of two different bone scaffold materials, sintered tricalciumphosphate and a titanium alloy (Ti6Al4V), were determined by mechanical and biomechanical testing. All scaffolds were fabricated by means of additive manufacturing techniques with identical design and controlled pore geometry. Small-sized sintered TCP scaffolds (10 mm diameter, 21 mm length) were fabricated as dense and open-porous samples and tested in an axial loading procedure. Material properties for titanium alloy were determined by using both tensile (dense) and compressive test samples (open-porous). Furthermore, large-sized open-porous TCP and titanium alloy scaffolds (30 mm in height and diameter, 700 µm pore size) were tested in a biomechanical setup simulating a large segmental bone defect using a composite femur stabilized with an osteosynthesis plate. Static physiologic loads (1.9 kN) were applied within these tests. Ultimate compressive strength of the TCP samples was 11.2 ± 0.7 MPa and 2.2 ± 0.3 MPa, respectively, for the dense and the open-porous samples. Tensile strength and ultimate compressive strength was 909.8 ± 4.9 MPa and 183.3 ± 3.7 MPa, respectively, for the dense and the open-porous titanium alloy samples. Furthermore, the biomechanical results showed good mechanical stability for the titanium alloy scaffolds. TCP scaffolds failed at 30% of the maximum load. Based on recent data, the 3D printed TCP scaffolds tested cannot currently be recommended for high load-bearing situations. Scaffolds made of titanium could be optimized by adapting the biomechanical requirements.

  16. Plug-In Electric Vehicle Handbook for Consumers (Brochure)

    Energy Technology Data Exchange (ETDEWEB)

    2011-09-01

    Plug-in electric vehicles (PEVs) are entering the automobile market and are viable alternatives to conventional vehicles. This guide for consumers describes the basics of PEV technology, PEV benefits, how to select the right PEV, charging a PEV, and PEV maintenance.

  17. Alternative Fuels Data Center: Plug-In Hybrid Electric Vehicles

    Science.gov (United States)

    . Fueling and Driving Options Plug-in hybrid electric vehicle batteries can be charged by an outside sized hybrid electric vehicle. If the vehicle is driven a shorter distance than its all-electric range drives the wheels almost all of the time, but the vehicle can switch to work like a parallel hybrid at

  18. Biodegradable microfabricated plug-filters for glaucoma drainage devices.

    Science.gov (United States)

    Maleki, Teimour; Chitnis, Girish; Park, Jun Hyeong; Cantor, Louis B; Ziaie, Babak

    2012-06-01

    We report on the development of a batch fabricated biodegradable truncated-cone-shaped plug filter to overcome the postoperative hypotony in nonvalved glaucoma drainage devices. Plug filters are composed of biodegradable polymers that disappear once wound healing and bleb formation has progressed past the stage where hypotony from overfiltration may cause complications in the human eye. The biodegradable nature of device eliminates the risks associated with permanent valves that may become blocked or influence the aqueous fluid flow rate in the long term. The plug-filter geometry simplifies its integration with commercial shunts. Aqueous humor outflow regulation is achieved by controlling the diameter of a laser-drilled through-hole. The batch compatible fabrication involves a modified SU-8 molding to achieve truncated-cone-shaped pillars, polydimethylsiloxane micromolding, and hot embossing of biodegradable polymers. The developed plug filter is 500 μm long with base and apex plane diameters of 500 and 300 μm, respectively, and incorporates a laser-drilled through-hole with 44-μm effective diameter in the center.

  19. Height suppression of tomato plug seedlings by an environment ...

    African Journals Online (AJOL)

    Experiments were conducted to investigate appropriate concentrations of plant growth retardants (PGRs) and duration of seed soaking in order to suppress hypocotyl length and plug seedling height of 2 tomato cultivars ( Lycopersicum esculentum Mill. cv. Seogeon and Seokwang). Daminozide (B-9), uniconazole ...

  20. Project Gasbuggy well plugging and site restoration plan

    International Nuclear Information System (INIS)

    1978-07-01

    The operational plan for conducting the final restoration work at the site of the first U.S. underground nuclear experiment for the stimulation of low-productivity natural gas reservoirs is given. The plan includes well plugging procedures, surface facilities decontamination and removal procedures, radiological guidelines, and environmental considerations

  1. End plug welding of nuclear fuel elements-AFFF experience

    International Nuclear Information System (INIS)

    Bhatt, R.B.; Singh, S.; Aniruddha Kumar; Amit; Arun Kumar; Panakkal, J.P.; Kamath, H.S.

    2004-01-01

    Advanced Fuel Fabrication Facility is engaged in the fabrication of mixed oxide (U,Pu)O 2 fuel elements of various types of nuclear reactors. Fabrication of fuel elements involves pellet fabrication, stack making, stack loading and end plug welding. The requirement of helium bonding gas inside the fuel elements necessitates the top end plug welding to be carried out with helium as the shielding gas. The severity of the service conditions inside a nuclear reactor imposes strict quality control criteria, which demands for almost defect free welds. The top end plug welding being the last process step in fuel element fabrication, any rejection at this stage would lead to loss of effort prior to this step. Moreover, the job becomes all the more difficult with mixed oxide (MOX) as the entire fabrication work has to be carried out in glove box trains. In the case of weld rejection, accepted pellets are salvaged by cutting the clad tube. This is a difficult task and recovery of pellets is low (requiring scrap recovery operation) and also leads to active metallic waste generation. This paper discusses the experience gained at AFFF, in the past 12 years in the area of end plug welding for different types of MOX fuel elements

  2. Plug-In Electric Vehicle Handbook for Fleet Managers (Brochure)

    Energy Technology Data Exchange (ETDEWEB)

    2012-04-01

    Plug-in electric vehicles (PEVs) are entering the automobile market and are viable alternatives to conventional vehicles. This guide for fleet managers describes the basics of PEV technology, PEV benefits for fleets, how to select the right PEV, charging a PEV, and PEV maintenance.

  3. Axicell design for the end plugs of MFTF-B

    International Nuclear Information System (INIS)

    Thomassen, K.I.; Karpenko, V.N.

    1982-01-01

    Certain changes in the end-plug design in the Mirror Fusion Test Facility (MFTF-B) are described. The Laboratory (LLNL) proposes to implement these changes as soon as possible in order to construct the machine in an axicell configuration. The present physics and technology goals as well as the project cost and schedule will not be affected by these changes

  4. Nuclear determination of saturation profiles in core plugs

    International Nuclear Information System (INIS)

    Sletsgaard, J.; Oelgaard, P.L.

    1997-01-01

    A method to determine liquid saturations in core plugs during flooding is of importance when the relative permeability and capillary pressure function are to be determined. This part of the EFP-95 project uses transmission of γ-radiation to determine these saturations. In γ-transmission measurements, the electron density of the given substance is measured. This is an advantage as compared to methods that use electric conductivity, since neither oil nor gas conducts electricity. At the moment a single 137 Cs-source is used, but a theoretical investigation of whether it is possible to determine three saturations, using two radioactive sources with different γ-energies, has been performed. Measurements were made on three core plugs. To make sure that the measurements could be reproduced, all the plugs had a point of reference, i.e. a mark so that it was possible to place the plug same way every time. Two computer programs for calculation of saturation and porosity and the experimental setup are listed. (EG)

  5. Valley plugs, land use, and phytogeomorphic response: Chapter 14

    Science.gov (United States)

    Pierce, Aaron R.; King, Sammy L.; Shroder, John F.

    2013-01-01

    Anthropogenic alteration of fluvial systems can disrupt functional processes that provide valuable ecosystem services. Channelization alters fluvial parameters and the connectivity of river channels to their floodplains which is critical for productivity, nutrient cycling, flood control, and biodiversity. The effects of channelization can be exacerbated by local geology and land-use activities, resulting in dramatic geomorphic readjustments including the formation of valley plugs. Considerable variation in the response of abiotic processes, including surface hydrology, subsurface hydrology, and sedimentation dynamics, to channelization and the formation of valley plugs. Altered abiotic processes associated with these geomorphic features and readjustments influence biotic processes including species composition, abundance, and successional processes. Considerable interest exists for restoring altered fluvial systems and their floodplains because of their social and ecological importance. Understanding abiotic and biotic responses of channelization and valley-plug formation within the context of the watershed is essential to successful restoration. This chapter focuses on the primary causes of valley-plug formation, resulting fluvial-geomorphic responses, vegetation responses, and restoration and research needs for these systems.

  6. A Rotating Plug Model of Friction Stir Welding Heat Transfer

    Science.gov (United States)

    Raghulapadu J. K.; Peddieson, J.; Buchanan, G. R.; Nunes, A. C.

    2006-01-01

    A simplified rotating plug model is employed to study the heat transfer phenomena associated with the fiction stir welding process. An approximate analytical solution is obtained based on this idealized model and used both to demonstrate the qualitative influence of process parameters on predictions and to estimate temperatures produced in typical fiction stir welding situations.

  7. Choosing Wisely When It Comes to Eye Care: Punctal Plugs for Dry Eye

    Science.gov (United States)

    ... of Our 5-Part Series: Punctal Plugs for Dry Eye Making healthy lifestyle choices can help you protect ... discuss each item in detail. Punctal Plugs for Dry Eye Dry eye is a condition that millions of ...

  8. Instrumentation development for the Waste Isolation Pilot Plant (WIPP) borehole plugging program (BHP)

    International Nuclear Information System (INIS)

    Cook, C.W.

    1979-11-01

    This report discusses the instrumentation development needs of the borehole testing program as it now exists. Although requirements may change as the program progresses, the items indicated are basic to any borehole plugging program. Instrumentation is discussed both for the plug environment and for the plug itself. For the plug environment, a probe for measuring the disturbed region and a coordinate logging tool are required. For the plug itself, instrumentation includes measurements above, within, and below the plug. Instrumentation for most measurements above the plug is currently available; for measurements within and below the plug, however, further development is required. Specifically, resistivity, induction, and acoustic probes; an in situ stressmeter; and a hardwire, feedthrough system need to be developed

  9. Process and device for extracting a cylindrical element such a plug of a small diameter tube

    International Nuclear Information System (INIS)

    Ferlay, J.C.; Gente, D.; Jouin, D.

    1992-01-01

    The plug engaged in a steam generator tube is extracted by first machining away the expander and a part of its side wall then pulling the remainder of the plug from the tube with a tool engaging its closed end

  10. Preparation of titanium diboride powders from titanium alkoxide and ...

    Indian Academy of Sciences (India)

    Administrator

    Department of Materials and Manufacturing Process, Malek Ashtar University of Technology, Tehran. 15875-1744, Iran ... Titanium diboride is a hard refractory material with a high melting point ... (λ = 1⋅540598 Å) radiation. Morphology of the ...

  11. Uranium dioxide sintering Kinetics and mechanisms under controlled oxygen potentials

    International Nuclear Information System (INIS)

    Freitas, C.T. de.

    1980-06-01

    The initial, intermediate, and final sintering stages of uranium dioxide were investigated as a function of stoichiometry and temperature by following the kinetics of the sintering reaction. Stoichiometry was controlled by means of the oxygen potential of the sintering atmosphere, which was measured continuously by solid-state oxygen sensors. Included in the kinetic study were microspheres originated from UO 2 gels and UO 2 pellets produced by isostatic pressing ceramic grade powders. The microspheres sintering behavior was examined using hot-stage microscopy and a specially designed high-temperature, controlled atmosphere furnace. This same furnace was employed as part of an optical dilatometer, which was utilized in the UO 2 pellet sintering investigations. For controlling the deviations from stoichiometry during heat treatment, the oxygen partial pressure in the sintering atmosphere was varied by passing the gas through a Cu-Ti-Cu oxygen trap. The trap temperature determined the oxygen partial pressure of the outflowing mixture. Dry hydrogen was also used in some of the UO sub(2+x) sintering experiments. The determination of diametrial shrinkages and sintering indices was made utilizing high-speed microcinematography and ultra-microbalance techniques. It was observed that the oxygen potential has a substantial influence on the kinetics of the three sintering stages. The control of the sintering atmosphere oxygen partial pressure led to very fast densification of UO sub(2+x). Values in the interval 95.0 to 99.5% of theoretical density were reached in less than one minute. Uranium volume diffusion is the dominant mechanism in the initial and intermediate sintering stages. For the final stage, uranium grain boundary diffusion was found to be the main sintering mechanism. (Author) [pt

  12. Electrical characterization of zirconia-niobium and zirconia-titanium composites

    International Nuclear Information System (INIS)

    Reis, S.T. dos.

    1993-01-01

    Zirconia-niobium and zirconia-titanium composites were made by powder mixing, cold pressing, and vacuum sintering at 1600 0 C. The metallic particles were added in the proportion of 0-50% by volume. Electrical resistivity measurements were performed by the two probes and the four probes d.c. method as a function of metallic particle concentration. Electrical resistivity of these composites decreased sharply in the region of 30-40 vol% Nb or Ti, in agreement with the percolation theory. Tests in an induction furnace were performed to check the self-heating response of these composites. (author). 33 refs, 40 figs, 11 tabs

  13. Custom-made prefabricated titanium miniplates in Le Fort I osteotomies: principles, procedure and clinical insights.

    Science.gov (United States)

    Philippe, B

    2013-08-01

    This paper describes a new type of miniplate system that is designed and custom made during virtual surgery planning based on an individual patient's osteotomy. These miniplates are prefabricated with commercially pure porous titanium using direct metal laser sintering. The principles that guide the conception and production of this new miniplate are presented. The surgical procedure from the stage of virtual surgery planning until the final Le Fort I osteotomy and bone fixation are described using a case example. Copyright © 2013 International Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.

  14. Fiscal Year 1993 Well Plugging and Abandonment Program Summary Report Y-12 Plant, Oak Ridge, Tennessee

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1994-09-01

    This report is a synopsis of the progress of the well plugging and abandonment program at the Y-12 Plant, Oak Ridge, Tennessee, from October 1993 through August 1994. A total of 57 wells and borings were plugged and abandoned during the period of time covered in this report. All wells and borings were plugged and abandoned in accordance with the Monitoring Well Plugging and Abandonment Plan for the U.S. Department of Energy, Y-12 Plant, Oak Ridge, Tennessee.

  15. Fiscal year 1993 well plugging and abandonment program, Y-12 Plant, Oak Ridge, Tennessee

    Energy Technology Data Exchange (ETDEWEB)

    1993-09-01

    This report is a synopsis of the progress of the well plugging and abandonment program at the Y-12 Plant, Oak Ridge, Tennessee, from December 1992 through August 20, 1993. A total of 70 wells and borings were plugged and abandoned during the period of time covered in this report. All wells and borings were plugged and abandoned in accordance with the Monitoring Well Plugging and Abandonment Plan for the US Department of Energy, Y-12 Plant, Oak Ridge, Tennessee (HSW, Inc. 1991).

  16. Polysaccharides and bacterial plugging. Final report, 1992--1993

    Energy Technology Data Exchange (ETDEWEB)

    Fogler, H.S.

    1995-02-01

    In situ core plugging experiments and transport experiments, using the model bacteria Leuconostoc m., have been conducted. Results demonstrated that cellular polysaccharide production increases cell distribution in porous media and caused an overall decrease in media permeability. Further, a parallel core plugging experiment was conducted and showed the feasibility of this system to divert injection fluid from high permeability zones into low permeability zones within porous media as is needed for profile modification. To implement this type of application, however, controlled placement of cells and rates of polymer production are needed. Therefore, kinetic studies were performed. A kinetic model was subsequently developed for Leuconostoc m. bacteria. This model is based on data generated from batch growth experiments and allows for the prediction of saccharide utilization, cell generation, and dextran production. These predictions can be used to develop injection strategies for field implementation. Transport and in situ growth micromodel experiments have shown how dextran allow cells to remain as clusters after cell division which enhanced cell capture and retention in porous media. Additional Damkohler experiments have been performed to determine the effects of the nutrient injection rate and nutrient concentration on the rate of porous media plugging. As shown experimentally and as predicted by a model for in situ growth, an increase in nutrient concentration and/or its injection rate will result in a faster rate of porous media plugging. Through continuum model simulations, it has been shown that the initial cell profiles play a key role on the core plugging rate. Controlling the location of the inoculating cells is thus another key factor in using bacteria for profile modification.

  17. Oscillation of an isolated liquid plug inside a dry capillary

    Science.gov (United States)

    Srinivasan, Vyas; Kumar, Siddhartha; Asfer, Mohammed; Khandekar, Sameer

    2017-11-01

    The present work reports an experimental study on the dynamics of partially wetting isolated liquid plug (DI water), which is made to oscillate inside a square, glass capillary tube (1 mm × 1 mm; 60 mm length). The liquid plug is made to oscillate pneumatically at two different frequencies (0.25 and 0.35 Hz), using a cam-follower mechanism. Bright field imaging is used to visualize the three-phase contact line behavior, while, micro-Particle Imaging Velocimetry (PIV) apparatus is used to discern the nature of flow inside the oscillating liquid plug. During a cycle, due to the partial wetting nature of DI water, the three-phase contact line at the menisci gets pinned at the extreme end of each stroke, where the dynamic apparent contact angle gets drastically altered before the initiation of the next stroke. The difference between the apparent contact angle of the front and rear meniscus are seen to be a function of the oscillating frequency; the difference increasing with increasing frequency. The flow inside the liquid plug reveals unique non-Poiseuille flow features near the meniscus, due to free-slip boundary condition, which leads to formation of distinct vortex pairs behind it. The vortices too change their direction during each stroke of the oscillation, eventually leading to an alternating recirculation pattern inside the plug. The results clearly indicate that improved mathematical models are required for predicting transport parameters in such flows, which are important in engineering systems such as pulsating heat pipes, lab-on-chip devices and PEM fuel cells.

  18. Hydrogen in titanium alloys

    International Nuclear Information System (INIS)

    Wille, G.W.; Davis, J.W.

    1981-04-01

    The titanium alloys that offer properties worthy of consideration for fusion reactors are Ti-6Al-4V, Ti-6Al-2Sn-4Zr-2Mo-Si (Ti-6242S) and Ti-5Al-6Sn-2Zr-1Mo-Si (Ti-5621S). The Ti-6242S and Ti-5621S are being considered because of their high creep resistance at elevated temperatures of 500 0 C. Also, irradiation tests on these alloys have shown irradiation creep properties comparable to 20% cold worked 316 stainless steel. These alloys would be susceptible to slow strain rate embrittlement if sufficient hydrogen concentrations are obtained. Concentrations greater than 250 to 500 wppm hydrogen and temperatures lower than 100 to 150 0 C are approximate threshold conditions for detrimental effects on tensile properties. Indications are that at the elevated temperature - low hydrogen pressure conditions of the reactors, there would be negligible hydrogen embrittlement

  19. Microwave sintering of nano size powder β-TCP bioceramics

    Directory of Open Access Journals (Sweden)

    Mirhadi B.

    2014-01-01

    Full Text Available A nano sized beta tricalcium phosphate (β-TCP powder was conventional sintered (CS and microwave sintered (MW, in order to obtain dense β-TCP ceramics. In this work the effect of microwave sintering conditions on the microstructure, phase composition and mechanical properties of materials based on tricalcium phosphate (TCP was investigated by SEM (scanning electron microscopyand XRD(X-ray diffraction and then compared with conventional sintered samples. Nano-size β-TCP powders with average grain size of 80 nm were prepared by the wet chemical precipitation method with calcium nitrate and diammonium hydrogen phosphate as calcium and phosphorus precursors, respectively. The precipitation process employed was also found to be suitable for the production of submicrometre β-TCP powder in situ. The β-TCP samples microwave (MW sintered for 15 min at 1100°C, with average grain size of 3μm, showed better densification, higher density and certainly higher hardness than samples conventionally sintered for 2 h at the same temperature. By comparing sintered and MW sintered β-TCP samples, it was concluded that MW sintered β-TCP samples have superior mechanical properties.

  20. Microwave sintering of zirconia toughened alumina at 28GHz

    International Nuclear Information System (INIS)

    Samandi, M.; Ji, H.; Miyake, S.

    1998-01-01

    Microwave radiation from a 10 kW, CW gyrotron operating at 28 GHz was employed to sinter 10% zirconia toughened alumina (ZTA) ceramic samples. It has been established that the use of millimetre wave radiation circumvents the difficulties encountered during the sintering of ceramics, i e. formation of hot spot, by radiation at industrially permissible frequency of 2.45GHz. Further, careful density measurement and microstructural characterisation of mm- wave and conventionally sintered samples by XRD, SEM and TEM has unequivocally demonstrated the effectiveness of mm-wave radiation for obtaining high density ceramics at lower sintering temperatures. Copyright (1998) Australasian Ceramic Society

  1. HAp physical investigation - the effect of sintering temperature

    International Nuclear Information System (INIS)

    Mohd Reusmaazran Yusof; Idris Besar; Rusnah Mustaffa; Cik Rohaida Che Hak

    2004-01-01

    The paper presents the effect of sintering temperature on the physical properties of porous hydroxyapatite (HAp). In this study, the HAp was prepared using polymeric sponge techniques with different binder concentration. The sintering process was carried out in air for temperature ranging from 1200 degree C to 1600 degree C. Different physical properties namely density and porosity were observed at different sintering temperatures. The HAp prepared with higher PVP binder showed a slightly decreased in apparent density with increasing sintering temperature, while those HAp prepared with lower PVP showed a slightly increase in apparent density with increasing sintering temperature. The total porosity was found to be approximately constant in the whole sintering temperature range. However, closed porosity decreases with increasing sintering temperature for HAp prepared by lower binder concentration. On the other hand, the HAp prepared by higher binder concentration HAp showed increasing closed porosity with increasing sintering temperature. Other features such as the influence of sintering temperatures on grain and strut also be presented in this paper. (Author)

  2. 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

  3. 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

  4. Properties, structure and machnining capabilities sintered corundum abrasives

    Directory of Open Access Journals (Sweden)

    Cz.J. Niżankowski

    2010-07-01

    Full Text Available The diversity of sintered corundum abrasives used in both bonded and in the embankment of abrasive tools currently poses substantialproblems for their choice of technology to specific tasks. Therefore performed a comparative study of ownership structures and capacitiesof elected representatives machnining sintered corundum abrasives of different generations, and this is normal sintered alumina,submicrocrystalline alumina sintered and nanocrystalline alumina sintered. Were studied some properties of a set of abrasive particles,physicochemical properties and structural and mechanical and technological properties. The studies used the method of microscopicmeasurement to determine the shape of abrasive particles, the pycnometer to determine the density of abrasive, a spectrometer todetermine the chemical composition of the magnetic analyzer for determining the magnetic fraction, scanning electron microscope toanalysis of abrasive grains and a special position to designate the machining capacity abrasive grains. The results showed a significantincrease in machining capacity sintered corundum abrasives with increasing degree of fragmentation of the crystallites sintered corundum abrasives and distinctive bands in the emerging microchip. The originality of the development provides a comparative summary ofproperties of sintered corundum abrasives of different generations and functions obtained by the author making the change in value indexof machininhcapacity grit from cutting speeds for different generations of sintered corundum.

  5. 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.

  6. Finishing of additively manufactured titanium alloy by shape adaptive grinding (SAG)

    Science.gov (United States)

    Beaucamp, Anthony T.; Namba, Yoshiharu; Charlton, Phillip; Jain, Samyak; Graziano, Arthur A.

    2015-06-01

    In recent years, rapid prototyping of titanium alloy components for medical and aeronautics application has become viable thanks to advances in technologies such as electron beam melting (EBM) and selective laser sintering (SLS). However, for many applications the high surface roughness generated by additive manufacturing techniques demands a post-finishing operation to improve the surface quality prior to usage. In this paper, the novel shape adaptive grinding process has been applied to finishing titanium alloy (Ti6Al4V) additively manufactured by EBM and SLS. It is shown that the micro-structured surface layer resulting from the melting process can be removed, and the surface can then be smoothed down to less than 10 nm Ra (starting from 4-5 μm Ra) using only three different diamond grit sizes. This paper also demonstrates application of the technology to freeform shapes, and documents the dimensional accuracy of finished artifacts.

  7. Titanium dioxide encapsulation of supported Ag nanoparticles on the porous silica bead for increased photocatalytic activity

    Science.gov (United States)

    Liu, Hui; Deng, Lu; Sun, Chaochao; Li, Junqi; Zhu, Zhenfeng

    2015-01-01

    A new synthetic strategy has been developed to encapsulate Ag nanoparticles in heterogeneous catalysts to prevent their dropping and sintering. Ag nanoparticles with diameters about 5-10 nm were first supported on the porous silica bead. These were then covered with a fresh layer of titanium dioxide with the thickness about 5 nm. SEM and TEM images were used to confirm the success of each synthesis step, and the photocatalytic activity of the as-synthesized samples was evaluated by photocatalytic decolorization of Rhodamine B (Rh B) aqueous solution at ambient temperature under both UV and visible light irradiation. The resulting titanium dioxide encapsulated Ag nanoparticles exhibited an enhanced photocatalytic activity under both UV and visible light irradiation, this can be attributed to effective charge separation and light harvesting of the plasmonic silver nanoparticles decoration, even the reducing of the exciton recombination rate caused by the small grain size of anatase TiO2 nanocrystals.

  8. Finishing of additively manufactured titanium alloy by shape adaptive grinding (SAG)

    International Nuclear Information System (INIS)

    Beaucamp, Anthony T; Namba, Yoshiharu; Charlton, Phillip; Jain, Samyak; Graziano, Arthur A

    2015-01-01

    In recent years, rapid prototyping of titanium alloy components for medical and aeronautics application has become viable thanks to advances in technologies such as electron beam melting (EBM) and selective laser sintering (SLS). However, for many applications the high surface roughness generated by additive manufacturing techniques demands a post-finishing operation to improve the surface quality prior to usage. In this paper, the novel shape adaptive grinding process has been applied to finishing titanium alloy (Ti6Al4V) additively manufactured by EBM and SLS. It is shown that the micro-structured surface layer resulting from the melting process can be removed, and the surface can then be smoothed down to less than 10 nm Ra (starting from 4–5 μm Ra) using only three different diamond grit sizes. This paper also demonstrates application of the technology to freeform shapes, and documents the dimensional accuracy of finished artifacts. (paper)

  9. Synchrotron X-ray CT characterization of titanium parts fabricated by additive manufacturing. Part II. Defects.

    Science.gov (United States)

    Scarlett, Nicola Vivienne Yorke; Tyson, Peter; Fraser, Darren; Mayo, Sheridan; Maksimenko, Anton

    2016-07-01

    Synchrotron X-ray tomography (SXRT) has been applied to the study of defects within three-dimensional printed titanium parts. These parts were made using the Arcam EBM(®) (electron beam melting) process which uses powdered titanium alloy, Ti64 (Ti alloy with approximately 6%Al and 4%V) as the feed and an electron beam for the sintering/welding. The experiment was conducted on the Imaging and Medical Beamline of the Australian Synchrotron. The samples represent a selection of complex shapes with a variety of internal morphologies. Inspection via SXRT has revealed a number of defects which may not otherwise have been seen. The location and nature of such defects combined with detailed knowledge of the process conditions can contribute to understanding the interplay between design and manufacturing strategy. This fundamental understanding may subsequently be incorporated into process modelling, prediction of properties and the development of robust methodologies for the production of defect-free parts.

  10. 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.

  11. Alternative Fuels Data Center: Signage for Plug-In Electric Vehicle

    Science.gov (United States)

    Send a link to Alternative Fuels Data Center: Signage for Plug-In Electric Vehicle Charging Stations to someone by E-mail Share Alternative Fuels Data Center: Signage for Plug-In Electric Vehicle Charging Stations on Facebook Tweet about Alternative Fuels Data Center: Signage for Plug-In Electric Vehicle

  12. Alternative Fuels Data Center: Hybrid and Plug-In Electric Vehicle

    Science.gov (United States)

    Conversions Hybrid and Plug-In Electric Vehicle Conversions to someone by E-mail Share Alternative Fuels Data Center: Hybrid and Plug-In Electric Vehicle Conversions on Facebook Tweet about Alternative Fuels Data Center: Hybrid and Plug-In Electric Vehicle Conversions on Twitter Bookmark Alternative

  13. Test Confessions : A Study of Testing Practices for Plug-in Systems

    NARCIS (Netherlands)

    Greiler, M.; Van Deursen, A.; Storey, M.A.

    2011-01-01

    Testing plug-in-based systems is challenging due to complex interactions among many different plug-ins, and variations in version and configuration. The objective of this paper is to increase our understanding of what testers and developers think and do when it comes to testing plug-inbased systems.

  14. Rotating plug size study for liquid-metal fast breeder reactors

    International Nuclear Information System (INIS)

    Nemeth, L.J.

    1980-01-01

    A study was performed to evaluate possible rotating plug arrangements. The three-, two-, and one-rotating plug schemes were developed using a set of established restrictions and component sizes. The three-rotating plug configuration is the recommended reference design

  15. 30 CFR 250.1711 - When will MMS order me to permanently plug a well?

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 2 2010-07-01 2010-07-01 false When will MMS order me to permanently plug a well? 250.1711 Section 250.1711 Mineral Resources MINERALS MANAGEMENT SERVICE, DEPARTMENT OF THE... Activities Permanently Plugging Wells § 250.1711 When will MMS order me to permanently plug a well? MMS will...

  16. Fast plasma sintering delivers functional graded materials components with macroporous structures and osseointegration properties.

    Science.gov (United States)

    Godoy, R F; Coathup, M J; Blunn, G W; Alves, A L; Robotti, P; Goodship, A E

    2016-04-13

    We explored the osseointegration potential of two macroporous titanium surfaces obtained using fast plasma sintering (FPS): Ti macroporous structures with 400-600 µmØ pores (TiMac400) and 850-1000 µmØ pores (TiMac850). They were compared against two surfaces currently in clinical use: Ti-Growth® and air plasma spray (Ti-Y367). Each surface was tested, once placed over a Ti-alloy and once onto a CoCr bulk substrate. Implants were placed in medial femoral condyles in 24 sheep. Samples were explanted at four and eight weeks after surgery. Push-out loads were measured using a material-testing system. Bone contact and ingrowth were assessed by histomorphometry and SEM and EDX analyses. Histology showed early osseointegration for all the surfaces tested. At 8 weeks, TiMac400, TiMac850 and Ti-Growth® showed deep bone ingrowth and extended colonisation with newly formed bone. The mechanical push-out force was equal in all tested surfaces. Plasma spray surfaces showed greater bone-implant contact and higher level of pores colonisation with new bone than FPS produced surfaces. However, the void pore area in FPS specimens was significantly higher, yet the FPS porous surfaces allowed a deeper osseointegration of bone to implant. FPS manufactured specimens showed similar osseointegration potential to the plasma spray surfaces for orthopaedic implants. FPS is a useful technology for manufacturing macroporous titanium surfaces. Furthermore, its capability to combine two implantable materials, using bulk CoCr with macroporous titanium surfaces, could be of interest as it enables designers to conceive and manufacture innovative components. FPS delivers functional graded materials components with macroporous structures optimised for osseointegration.

  17. Thermomechanical treatment of titanium alloys

    International Nuclear Information System (INIS)

    Khorev, A.K.

    1979-01-01

    The problems of the theory and practical application of thermomechanical treatment of titanium alloys are presented. On the basis of the systematic investigations developed are the methods of thermomechanical treatment of titanium alloys, established are the optimum procedures and produced are the bases of their industrial application with an account of alloy technological peculiarities and the procedure efficiency. It is found that those strengthening methods are more efficient at which the contribution of dispersion hardening prevails over the strengthening by phase hardening

  18. Influencing Factors for the Microstructure and Mechanical Properties of Micro Porous Titanium Manufactured by Metal Injection Molding

    Directory of Open Access Journals (Sweden)

    Zhen Lu

    2016-04-01

    Full Text Available Porous titanium is a new structural and functional material. It is widely used in many fields since it integrates the properties of biomaterials with those of metallic foam. A new technology that combines both the preparation and forming of porous materials has been proposed in this paper. Moreover, a new solder was developed that could be employed in the joining of porous materials. Influencing factors for microstructure and mechanical properties of the parent material and joint interface are identified. Metal injection molding (MIM technology was used for fabricating porous materials. The feedstock for injection molding of porous titanium powders was prepared from titanium powders and a polymer-based binder system. In addition, the proportion of powder loading and binders was optimized. Through MIM technology, a porous titanium filter cartridge was prepared. For the purpose of investigating the thermal debinding technology of the filter cartridge, effects of the sintering temperature on the porosity, morphology of micropores and mechanical properties were analyzed. It could be found that when the sintering temperature increased, the relative density, bending and compression strength of the components also increased. Moreover, the porosity reached 32.28% when the sintering temperature was 1000 °C. The microstructure morphology indicated that micropores connected with each other. Meanwhile, the strength of the components was relatively high, i.e., the bending and compression strength was 65 and 60 MPa, respectively. By investigating the joining technology of porous filter cartridges, the ideal components of the solder and pressure were determined. Further research revealed that the micropore structure of the joint interface is the same as that of the parent material, and that the bending strength of the joint interface is 40 MPa.

  19. Laser Surface Treatment of Sintered Alumina

    Science.gov (United States)

    Hagemann, R.; Noelke, C.; Kaierle, S.; Wesling, V.

    Sintered alumina ceramics are used as refractory materials for industrial aluminum furnaces. In this environment the ceramic surface is in permanent contact with molten aluminum resulting in deposition of oxidic material on its surface. Consequently, a lower volume capacity as well as thermal efficiency of the furnaces follows. To reduce oxidic adherence of the ceramic material, two laser-based surface treatment processes were investigated: a powder- based single-step laser cladding and a laser surface remelting. Main objective is to achieve an improved surface quality of the ceramic material considering the industrial requirements as a high process speed.

  20. 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.

  1. 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

  2. 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.

  3. 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.)

  4. Field-test programs of borehole plugs in southeastern New Mexico

    International Nuclear Information System (INIS)

    Christensen, C.L.; Peterson, E.W.

    1981-01-01

    This paper gives a general overview of the repository-sealing field test effort being conducted by Sandia National Laboratories in support of the Waste Isolation Pilot Plant in southeast New Mexico. Summary descriptions of supporting activities, such as performance assessment and plugging materials development, are included to create the connection between modeling and laboratory activities as they relate to field results. Results of tests on a portion of a 17-year-old plug (Plug 217) recovered from a mine horizon and the Bell Canyon Test, in which a cement plug was emplaced to isolate a naturally pressurized aquifer, are given. Conclusions from these field plugging tests are included

  5. 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)

  6. 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 ...

  7. 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...

  8. 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.

  9. Direct Metal Laser Sintering: A Digitised Metal Casting Technology

    OpenAIRE

    Venkatesh, K. Vijay; Nandini, V. Vidyashree

    2013-01-01

    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.

  10. 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.

  11. Sintering of uranium dioxide obtained by continuous precipitation of AUC

    International Nuclear Information System (INIS)

    Amaya, C.D.; Sterba, M.E.; Russo, D.O.

    1993-01-01

    The Nuclear Materials Division in Bariloche Atomic Center evaluates the ceramic behaviour of UO 2 powders obtained from continuously precipitated and reduced AUC (Ammonium Uranyl Tri Carbonate). An analysis is made of powder characteristics (particle morphology and size distribution and specific area) on behaviour of UO 2 during sintering (compaction, sintering, pore and grain microstructure, etc.). 1 ref

  12. CALCIUM OXIDE SINTERING IN ATMOSPHERES CONTAINING WATER AND CARBON DIOXIDE

    Science.gov (United States)

    The paper gives results of measurements of the effects of water vapor and CO2 on the sintering rate of nascent CaO, as a function of partial pressure and temperature using CaO prepared by rapid decomposition of CaCO3 and CA(OH)2. Each gas strongly catalyzed the sintering process ...

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

    Indian Academy of Sciences (India)

    ratures ranging from 570–630 ◦C. Microwave sintering at a heating rate of as high as 22◦. C/min resulted in ... The effect of heating mode and sintering temperature are discussed .... the compacts. This is attributed to the Zn evaporated from the.

  14. Flow induced vibration studies on PFBR control plug components

    Energy Technology Data Exchange (ETDEWEB)

    Prakash, V., E-mail: prakash@igcar.gov.in [Fast Reactor Technology Group, Indira Gandhi Centre for Atomic Research, Kalpakkam, Tamilnadu (India); Kumar, P. Anup; Anandaraj, M.; Thirumalai, M.; Anandbabu, C.; Rajan, K.K. [Fast Reactor Technology Group, Indira Gandhi Centre for Atomic Research, Kalpakkam, Tamilnadu (India)

    2012-09-15

    Highlights: Black-Right-Pointing-Pointer Flow induced vibration studies on Prototype Fast Breeder Reactor control plug model carried out. Black-Right-Pointing-Pointer Velocity similitude was followed for the study. Black-Right-Pointing-Pointer Frequencies and amplitude of vibrations of various control plug components measured. Black-Right-Pointing-Pointer Overall values of vibration are well within permissible limits. - Abstract: The construction of Prototype Fast Breeder Reactor (PFBR), a 500 MWe liquid sodium cooled reactor, is in progress at Kalpakkam in India. Control plug (CP) is located right above the core subassemblies in the hot pool. Control plug is an important component as many of the critical reactor parameters are sensed and controlled by the components housed in the control plug assembly. In PFBR primary circuit, components are basically thin walled, slender shells with diameter to thickness ratio ranging from 100 to 650. These components are prone to flow induced vibrations. The existence of free liquid (sodium) surfaces, which is the source of sloshing phenomenon and the operation of primary sodium pump in the primary pool are other potential sources of vibration of reactor components. Control plug is a hollow cylindrical shell structure and provides passages and support for 12 absorber rod drive mechanisms (ARDM) which consists of 9 control and safety rods and 3 diverse safety rods, 210 thermo wells to measure the sodium temperature at the exit of various fuel subassemblies, three failed fuel localization modules (FFLM) and acoustic detectors. It consists of a core cover plate (CCP), which forms the bottom end, two intermediate supports plate, i.e. lower stay plate (LSP) and upper stay plate (USP) and an outer shell. The CCP is located at a distance of 1.3 m from the core top. With such a gap, there will be long free hanging length of the thermocouple sleeves, Delayed neutron detector (DND) sampling tubes and ARDM shroud tubes and hence they are

  15. Wireless Plug and Play Control Systems: Hardware, Networks, and Protocols

    DEFF Research Database (Denmark)

    Meybodi, Soroush Afkhami

    2012-01-01

    This dissertation reports the result of efforts to identify and solve the problems that arise when a control system is to be designed for various industrial case studies of the Plug and Play Process Control (P3C) project that require autonomous addition/removal of sensors, actuators and subsystems...... in only one of the P3C case studies where all of the nodes of the wireless networked control system are placed underground and should be able to transmit data among themselves. It is not a trivial problem because the well known radio frequency electromagnetic waves face serious difficulties penetrating...... is recommended for wireless plug and play control systems. Formation and maintenance of clusters of nodes are directly linked to the top level application layer via a novel application-based routing metric. The proposed routing metric facilitates implementation of the networking topology in accordance...

  16. [Plug-technique for umbilical hernia repair in the adult].

    Science.gov (United States)

    Brancato, G; Privitera, A; Gandolfo, L; Donati, M; Caglià, P

    2002-02-01

    Umbilical hernia represents 6% of all abdominal wall hernias in the adult. Surgical repair should always be carried out due to possible occurrence of complications. Aim of this paper is to evaluate the efficacy of the plug-technique. From October 1995 to April 2000, the authors performed 21 operations for acquired umbilical hernia with a defect smaller than 4 cm. Local anesthesia was used and a light intravenous sedation added in particularly anxious patients. The repair was achieved by insertion of a polypropylene dart plug sutured to the margins of the hernial defect. All patients were up and about straightaway and were discharged within 24 hours of surgery. Postoperative pain was mild and required hospital analgesia in only 19% of cases and domiciliary analgesia in 24%. During a follow-up ranging from 6 to 60 months (mean 30), only one recurrence has been recorded. This tension-free technique allows immediate rehabilitation, with few complications and a low recurrence rate.

  17. A Plug and Produce Framework for Industrial Collaborative Robots

    DEFF Research Database (Denmark)

    Schou, Casper; Madsen, Ole

    2017-01-01

    Collaborative robots are today ever more interesting in response to the increasing need for agile manufacturing equipment. Contrary to traditional industrial robots, collaborative robots are intended for working in dynamic environments alongside the production staff. To cope with the dynamic...... environment and workflow, new configuration and control methods are needed compared to those of traditional industrial robots. The new methods should enable shop floor operators to reconfigure the robot. This article presents a plug and produce framework for industrial collaborative robots. The article...... focuses on the control framework enabling quick and easy exchange of hardware modules as an approach to achieving plug and produce. To solve this, an agent-based system is proposed building on top of the robot operating system. The framework enables robot operating system packages to be adapted...

  18. Plug and Process Loads Capacity and Power Requirements Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Sheppy, M.; Gentile-Polese, L.

    2014-09-01

    This report addresses gaps in actionable knowledge that would help reduce the plug load capacities designed into buildings. Prospective building occupants and real estate brokers lack accurate references for plug and process load (PPL) capacity requirements, so they often request 5-10 W/ft2 in their lease agreements. Limited initial data, however, suggest that actual PPL densities in leased buildings are substantially lower. Overestimating PPL capacity leads designers to oversize electrical infrastructure and cooling systems. Better guidance will enable improved sizing and design of these systems, decrease upfront capital costs, and allow systems to operate more energy efficiently. The main focus of this report is to provide industry with reliable, objective third-party guidance to address the information gap in typical PPL densities for commercial building tenants. This could drive changes in negotiations about PPL energy demands.

  19. Strength and stability of microbial plugs in porous media

    Energy Technology Data Exchange (ETDEWEB)

    Sarkar, A.K. [NIPER/BDM-Oklahoma, Inc., Bartlesville, OK (United States); Sharma, M.M.; Georgiou, G. [Univ. of Texas, Austin, TX (United States)

    1995-12-31

    Mobility reduction induced by the growth and metabolism of bacteria in high-permeability layers of heterogeneous reservoirs is an economically attractive technique to improve sweep efficiency. This paper describes an experimental study conducted in sandpacks using an injected bacterium to investigate the strength and stability of microbial plugs in porous media. Successful convective transport of bacteria is important for achieving sufficient initial bacteria distribution. The chemotactic and diffusive fluxes are probably not significant even under static conditions. Mobility reduction depends upon the initial cell concentrations and increase in cell mass. For single or multiple static or dynamic growth techniques, permeability reduction was approximately 70% of the original permeability. The stability of these microbial plugs to increases in pressure gradient and changes in cell physiology in a nutrient-depleted environment needs to be improved.

  20. Plug and Play Framework for Theories of Social Group Dynamics

    DEFF Research Database (Denmark)

    Rehm, Matthias; Endrass, Birgit; André, Elisabeth

    2006-01-01

    We present an extensible framework for behavior control of social agents in a multi-agent system that has the following features. It implements a basic repertoire of socio-psychological models of behavior and interpersonal interactions that can be plugged and unplugged at will depending on the sp......We present an extensible framework for behavior control of social agents in a multi-agent system that has the following features. It implements a basic repertoire of socio-psychological models of behavior and interpersonal interactions that can be plugged and unplugged at will depending...... on the specific context of the application. This enables us to test several theories in isolation or combination to increase the transparency of the system and to investigate how the inclusion of a certain theory influences the behavior of the agents. Unlike earlier approaches, our approach is not bound...

  1. Titanium nanostructures for biomedical applications

    International Nuclear Information System (INIS)

    Kulkarni, M; Gongadze, E; Perutkova, Š; A Iglič; Mazare, A; Schmuki, P; Kralj-Iglič, V; Milošev, I; Mozetič, M

    2015-01-01

    Titanium and titanium alloys exhibit a unique combination of strength and biocompatibility, which enables their use in medical applications and accounts for their extensive use as implant materials in the last 50 years. Currently, a large amount of research is being carried out in order to determine the optimal surface topography for use in bioapplications, and thus the emphasis is on nanotechnology for biomedical applications. It was recently shown that titanium implants with rough surface topography and free energy increase osteoblast adhesion, maturation and subsequent bone formation. Furthermore, the adhesion of different cell lines to the surface of titanium implants is influenced by the surface characteristics of titanium; namely topography, charge distribution and chemistry. The present review article focuses on the specific nanotopography of titanium, i.e. titanium dioxide (TiO 2 ) nanotubes, using a simple electrochemical anodisation method of the metallic substrate and other processes such as the hydrothermal or sol-gel template. One key advantage of using TiO 2 nanotubes in cell interactions is based on the fact that TiO 2 nanotube morphology is correlated with cell adhesion, spreading, growth and differentiation of mesenchymal stem cells, which were shown to be maximally induced on smaller diameter nanotubes (15 nm), but hindered on larger diameter (100 nm) tubes, leading to cell death and apoptosis. Research has supported the significance of nanotopography (TiO 2 nanotube diameter) in cell adhesion and cell growth, and suggests that the mechanics of focal adhesion formation are similar among different cell types. As such, the present review will focus on perhaps the most spectacular and surprising one-dimensional structures and their unique biomedical applications for increased osseointegration, protein interaction and antibacterial properties. (topical review)

  2. Titanium nanostructures for biomedical applications

    Science.gov (United States)

    Kulkarni, M.; Mazare, A.; Gongadze, E.; Perutkova, Š.; Kralj-Iglič, V.; Milošev, I.; Schmuki, P.; Iglič, A.; Mozetič, M.

    2015-02-01

    Titanium and titanium alloys exhibit a unique combination of strength and biocompatibility, which enables their use in medical applications and accounts for their extensive use as implant materials in the last 50 years. Currently, a large amount of research is being carried out in order to determine the optimal surface topography for use in bioapplications, and thus the emphasis is on nanotechnology for biomedical applications. It was recently shown that titanium implants with rough surface topography and free energy increase osteoblast adhesion, maturation and subsequent bone formation. Furthermore, the adhesion of different cell lines to the surface of titanium implants is influenced by the surface characteristics of titanium; namely topography, charge distribution and chemistry. The present review article focuses on the specific nanotopography of titanium, i.e. titanium dioxide (TiO2) nanotubes, using a simple electrochemical anodisation method of the metallic substrate and other processes such as the hydrothermal or sol-gel template. One key advantage of using TiO2 nanotubes in cell interactions is based on the fact that TiO2 nanotube morphology is correlated with cell adhesion, spreading, growth and differentiation of mesenchymal stem cells, which were shown to be maximally induced on smaller diameter nanotubes (15 nm), but hindered on larger diameter (100 nm) tubes, leading to cell death and apoptosis. Research has supported the significance of nanotopography (TiO2 nanotube diameter) in cell adhesion and cell growth, and suggests that the mechanics of focal adhesion formation are similar among different cell types. As such, the present review will focus on perhaps the most spectacular and surprising one-dimensional structures and their unique biomedical applications for increased osseointegration, protein interaction and antibacterial properties.

  3. 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.

  4. Densification of LSGM electrolytes using activated microwave sintering

    Science.gov (United States)

    Kesapragada, S. V.; Bhaduri, S. B.; Bhaduri, S.; Singh, P.

    Lanthanum gallate doped with alkaline rare earths (LSGM) powders were densified using an activated microwave sintering process for developing a dense stable electrolyte layer for applications in intermediate temperature-solid oxide fuel cells (IT-SOFCs). Due to heat generation in situ, the process of sintering gets activated with faster kinetics compared to a conventional sintering process. The effect of various microwave process parameters on the microstructure and phase formation was studied. The sintered pellets were characterized using scanning electron microscopy-energy dispersive analysis (SEM-EDAX), and X-ray diffraction (XRD). The density of LSGM pellets microwave sintered at 1350 °C for 20 min is greater than 95% theoretical density with a fine grained microstructure (˜2-3 μm) and without the presence of other phase(s).

  5. 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.)

  6. 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

  7. 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

  8. Effect of particle size distribution on sintering of tungsten

    International Nuclear Information System (INIS)

    Patterson, B.R.; Griffin, J.A.

    1984-01-01

    To date, very little is known about the effect of the nature of the particle size distribution on sintering. It is reasonable that there should be an effect of size distribution, and theory and prior experimental work examining the effects of variations in bimodal and continuous distributions have shown marked effects on sintering. Most importantly, even with constant mean particle size, variations in distribution width, or standard deviation, have been shown to produce marked variations in microstructure and sintering rate. In the latter work, in which spherical copper powders were blended to produce lognormal distributions of constant geometric mean particle size by weight frequency, blends with larger values of geometric standard deviation, 1nσ, sintered more rapidly. The goals of the present study were to examine in more detail the effects of variations in the width of lognormal particle size distributions of tungsten powder and determine the effects of 1nσ on the microstructural evolution during sintering

  9. 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.

  10. Enhancements to the Redmine Database Metrics Plug in

    Science.gov (United States)

    2017-08-01

    management web application has been adopted within the US Army Research Laboratory’s Computational and Information Sciences Directorate as a database...project management web application.∗ The Redmine plug-in† enabled the use of the numerous, powerful features of the web application. The many...distribution is unlimited. 2 • Selectable export of citations/references by type, writing style , and FY • Enhanced naming convention options for

  11. "Plug-and-play" edge-preserving regularization

    DEFF Research Database (Denmark)

    Chen, Donghui; Kilmer, Misha E.; Hansen, Per Christian

    2014-01-01

    In many inverse problems it is essential to use regularization methods that preserve edges in the reconstructions, and many reconstruction models have been developed for this task, such as the Total Variation (TV) approach. The associated algorithms are complex and require a good knowledge of large...... cosine transform.hence the term "plug-and-play" . We do not attempt to improve on TV reconstructions, but rather provide an easy-to-use approach to computing reconstructions with similar properties....

  12. Plug-In Electric Vehicle Handbook for Workplace Charging Hosts

    Energy Technology Data Exchange (ETDEWEB)

    None

    2013-08-01

    Plug-in electric vehicles (PEVs) have immense potential for increasing the country's energy, economic, and environmental security, and they will play a key role in the future of U.S. transportation. By providing PEV charging at the workplace, employers are perfectly positioned to contribute to and benefit from the electrification of transportation. This handbook answers basic questions about PEVs and charging equipment, helps employers assess whether to offer workplace charging for employees, and outlines important steps for implementation.

  13. A Rigorous Methodology for Analyzing and Designing Plug-Ins

    DEFF Research Database (Denmark)

    Fasie, Marieta V.; Haxthausen, Anne Elisabeth; Kiniry, Joseph

    2013-01-01

    . This paper addresses these problems by describing a rigorous methodology for analyzing and designing plug-ins. The methodology is grounded in the Extended Business Object Notation (EBON) and covers informal analysis and design of features, GUI, actions, and scenarios, formal architecture design, including...... behavioral semantics, and validation. The methodology is illustrated via a case study whose focus is an Eclipse environment for the RAISE formal method's tool suite....

  14. Mesh Plug Repair of Inguinal Hernia; Single Surgeon Experience

    Directory of Open Access Journals (Sweden)

    Ahmet Serdar Karaca

    2013-10-01

    Full Text Available Aim: Mesh repair of inguinal hernia repairs are shown to be an effective and reliable method. In this study, a single surgeon%u2019s experience with plug-mesh method performs inguinal hernia repair have been reported. Material and Method: 587 patients with plug-mesh repair of inguinal hernia, preoperative age, body / mass index, comorbid disease were recorded in terms of form. All of the patients during the preoperative and postoperative hernia classification of information, duration of operation, antibiotics, perioperative complications, and later, the early and late postoperative complications, infection, recurrence rates and return to normal daily activity, verbal pain scales in terms of time and postoperative pain were evaluated. Added to this form of long-term pain ones. The presence of wound infection was assessed by the presence of purulent discharge from the incision. Visual analog scale pain status of the patients was measured. Results: 587 patients underwent repair of primary inguinal hernia mesh plug. One of the patients, 439 (74% of them have adapted follow-ups. Patients%u2019 ages ranged from 18-86. Was calculated as the mean of 47±18:07. Follow-up period of the patients was found to be a minimum of 3 months, maximum 55 months. Found an average of 28.2±13.4 months. Mean duration of surgery was 35.07±4.00 min (min:22mn-max:52mn, respectively. When complication rates of patients with recurrence in 2 patients (0.5%, hematoma development (1.4% in 6 patients, the development of infection in 11 patients (2.5% and long-term groin pain in 4 patients (0.9% appeared. Discussion: In our experience, the plug-mesh repair of primary inguinal hernia repair safe, effective low recurrence and complication rates can be used.

  15. Glow plug ignitor tests in H2 mixtures

    International Nuclear Information System (INIS)

    Liparulo, N.J.; Olhoeft, J.E.; Paddleford, D.F.

    1981-01-01

    The AEP, TVA and DUKE Electric Power companies, in cooperation with Westinghouse Electric Corporation have defined a testing program to determine the effectiveness of a glow plug hydrogen ignition system. The ignitor's capability was demonstrated for both static and dynamic conditions. Tests were performed with both spray addition and fan induced turbulence. It ignited hydrogen for all tests performed. The results of tests did not differ significantly from similar tests data previously reported. This report presents a discussion of the test results

  16. National Plug-In Electric Vehicle Infrastructure Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Wood, Eric W. [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Rames, Clement L. [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Muratori, Matteo [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Srinivasa Raghavan, Seshadri [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Melaina, Marc W. [National Renewable Energy Laboratory (NREL), Golden, CO (United States)

    2017-09-15

    This document describes a study conducted by the National Renewable Energy Laboratory quantifying the charging station infrastructure required to serve the growing U.S. fleet of plug-in electric vehicles (PEVs). PEV sales, which include plug-in hybrid electric vehicles (PHEVs) and battery electric vehicles (BEVs), have surged recently. Most PEV charging occurs at home, but widespread PEV adoption will require the development of a national network of non-residential charging stations. Installation of these stations strategically would maximize the economic viability of early stations while enabling efficient network growth as the PEV market matures. This document describes what effective co-evolution of the PEV fleet and charging infrastructure might look like under a range of scenarios. To develop the roadmap, NREL analyzed PEV charging requirements along interstate corridors and within urban and rural communities. The results suggest that a few hundred corridor fast-charging stations could enable long-distance BEV travel between U.S. cities. Compared to interstate corridors, urban and rural communities are expected to have significantly larger charging infrastructure requirements. About 8,000 fast-charging stations would be required to provide a minimum level of coverage nationwide. In an expanding PEV market, the total number of non-residential charging outlets or 'plugs' required to meet demand ranges from around 100,000 to more than 1.2 million. Understanding what drives this large range in capacity requirements is critical. For example, whether consumers prefer long-range or short-range PEVs has a larger effect on plug requirements than does the total number of PEVs on the road. The relative success of PHEVs versus BEVs also has a major impact, as does the number of PHEVs that charge away from home. This study shows how important it is to understand consumer preferences and driving behaviors when planning charging networks.

  17. National Plug-In Electric Vehicle Infrastructure Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Muratori, Matteo [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Rames, Clement L [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Srinivasa Raghavan, Sesha [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Melaina, Marc W [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Wood, Eric W [National Renewable Energy Laboratory (NREL), Golden, CO (United States)

    2018-02-07

    This presentation describes a study conducted by the National Renewable Energy Laboratory quantifying the charging station infrastructure required to serve the growing U.S. fleet of plug-in electric vehicles (PEVs). PEV sales, which include plug-in hybrid electric vehicles (PHEVs) and battery electric vehicles (BEVs), have surged recently. Most PEV charging occurs at home, but widespread PEV adoption will require the development of a national network of non-residential charging stations. Installation of these stations strategically would maximize the economic viability of early stations while enabling efficient network growth as the PEV market matures. This document describes what effective co-evolution of the PEV fleet and charging infrastructure might look like under a range of scenarios. To develop the roadmap, NREL analyzed PEV charging requirements along interstate corridors and within urban and rural communities. The results suggest that a few hundred corridor fast-charging stations could enable long-distance BEV travel between U.S. cities. Compared to interstate corridors, urban and rural communities are expected to have significantly larger charging infrastructure requirements. About 8,000 fast-charging stations would be required to provide a minimum level of coverage nationwide. In an expanding PEV market, the total number of non-residential charging outlets or 'plugs' required to meet demand ranges from around 100,000 to more than 1.2 million. Understanding what drives this large range in capacity requirements is critical. For example, whether consumers prefer long-range or short-range PEVs has a larger effect on plug requirements than does the total number of PEVs on the road. The relative success of PHEVs versus BEVs also has a major impact, as does the number of PHEVs that charge away from home. This study shows how important it is to understand consumer preferences and driving behaviors when planning charging networks.

  18. Orbital Reconstruction: Patient-Specific Orbital Floor Reconstruction Using a Mirroring Technique and a Customized Titanium Mesh.

    Science.gov (United States)

    Tarsitano, Achille; Badiali, Giovanni; Pizzigallo, Angelo; Marchetti, Claudio

    2016-10-01

    Enophthalmos is a severe complication of primary reconstruction of orbital floor fractures. The goal of secondary reconstruction procedures is to restore symmetrical globe positions to recover function and aesthetics. The authors propose a new method of orbital floor reconstruction using a mirroring technique and a customized titanium mesh, printed using a direct metal laser-sintering method. This reconstructive protocol involves 4 steps: mirroring of the healthy orbit at the affected site, virtual design of a patient-specific orbital floor mesh, CAM procedures for direct laser-sintering of the customized titanium mesh, and surgical insertion of the device. Using a computed tomography data set, the normal, uninjured side of the craniofacial skeleton was reflected onto the contralateral injured side, and a reconstructive orbital floor mesh was designed virtually on the mirrored orbital bone surface. The solid-to-layer files of the mesh were then manufactured using direct metal laser sintering, which resolves the shaping and bending biases inherent in the indirect method. An intraoperative navigation system ensured accuracy of the entire procedure. Clinical outcomes were assessed using 3dMD photogrammetry and computed tomography data in 7 treated patients. The technique described here appears to be a viable method to correct complex orbital floor defects needing delayed reconstruction. This study represents the first step in the development of a wider experimental protocol for orbital floor reconstruction using computer-assisted design-computer-assisted manufacturing technology.

  19. Burst Test Qualification Analysis of DWPF Canister-Plug Weld

    International Nuclear Information System (INIS)

    Gupta, N.K.; Gong, Chung.

    1995-02-01

    The DWPF canister closure system uses resistance welding for sealing the canister nozzle and plug to ensure leak tightness. The welding group at SRTC is using the burst test to qualify this seal weld in lieu of the shear test in ASME B ampersand PV Code, Section IX, paragraph QW-196. The burst test is considered simpler and more appropriate than the shear test for this application. Although the geometry, loading and boundary conditions are quite different in the two tests, structural analyses show similarity in the failure mode of the shear test in paragraph QW-196 and the burst test on the DWPF canister nozzle Non-linear structural analyses are performed using finite element techniques to study the failure mode of the two tests. Actual test geometry and realistic stress strain data for the 304L stainless steel and the weld material are used in the analyses. The finite element models are loaded until failure strains are reached. The failure modes in both tests are shear at the failure points. Based on these observations, it is concluded that the use of a burst test in lieu of the shear test for qualifying the canister-plug weld is acceptable. The burst test analysis for the canister-plug also yields the burst pressures which compare favorably with the actual pressure found during burst tests. Thus, the analysis also provides an estimate of the safety margins in the design of these vessels

  20. End plug for fuel rod and welding method therefor

    International Nuclear Information System (INIS)

    Yoneda, Hiroshi; Murakami, Kazuo; Oyama, Jun-ichi.

    1996-01-01

    An end plug of a fuel rod comprises a pressure-insertion portion having a diameter somewhat greater than the inner diameter of a fuel cladding tube and a welding portion having a diameter substantially the same as the outer diameter of the cladding tube. A V-shaped recess having an outer diameter smaller than the greatest outer diameter of the pressure-insertion portion is formed over the entire circumferential surface of the outer circumference of the connection portion of the pressure-insertion portion and the welding portion. The pressure-insertion portion of the end plug is inserted to the end of the cladding tube till the end of the cladding tube abuts against the inclined surface of the V-shaped recess. The abutting surfaces of the end plug and the cladding tube are subjected to resistance welding in this state. The inner portion bulged from the inclined surface of the V-shaped recess is filled in the recess in a molten state. Lowering of temperature of the cladding tube in the vicinity of the welded portion is decreased by γ heat during reactor operation. Accordingly, lowering of ductility of the cladding tube and degradation of material of the welded region due to segregation of hydrogen in the cladding tube can be suppressed. (I.N.)