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Sample records for dement wc eds

  1. Synthesis of High Surface Area and Well Crystallized Mesoporous WC at Low Temperature with a Pore Structure Collapsed Replication Route

    Institute of Scientific and Technical Information of China (English)

    LI Hua; SHI Jianlin; CHEN Hangrong; ZHANG Lingxia; LI Lei

    2011-01-01

    An approach named "pore structure collapsed replication route" has been developed to prepare mesoporous WC materials with a high surface area (105 m2/g) and crystallized framework at a temperature as low as 700 ℃. The XRD, TEM, EDS, and BET characterizations were conducted to analyze the effects of the synthesis parameters and the template types on the structure of mesoporous WC. The compaction on the templates is the key to form mesoporous structure of WC while the templates help to control the size of crystalline. At a content of 7 wt% for the precursor of WC, the mesoporous WC could be formed with well ordered structure.

  2. Sampling and analysis of inactive radioactive waste tanks W-17, W-18, WC-5, WC-6, WC-8, and WC-11 through WC-14 at ORNL

    Energy Technology Data Exchange (ETDEWEB)

    Sears, M.B.; Giaquinto, J.M.; Griest, W.H.; Pack, R.T.; Ross, T.; Schenley, R.L.

    1995-12-01

    The sampling and analysis of nine inactive liquid low-level waste (LLLW) tanks at the Oak Ridge National Laboratory (ORNL) are described-tanks W-17, W-18, WC-5, WC-6, WC-8, and WC-11 through WC-14. Samples of the waste tank liquids and sludges were analyzed to determine (1) the major chemical constituents, (2) the principal radionuclides, (3) metals listed on the US Environmental Protection Agency (EPA) Contract Laboratory Program Inorganic Target Analyte List, (4) organic compounds, and (5) some physical properties. The organic chemical characterization consisted of determinations of the EPA Contract Laboratory Program Target Compound List volatile and semivolatile compounds, pesticides, and polychlorinated biphenyis (PCBs). This report provides data (1) to meet requirements under the Federal Facility Agreement (FFA) for the Oak Ridge Reservation to characterize the contents of LLLW tanks which have been removed from service and (2) to support planning for the treatment and disposal of the wastes.

  3. High Temperature Dry Sliding Friction and Wear Performance of Laser Cladding WC/Ni Composite Coating

    Directory of Open Access Journals (Sweden)

    YANG Jiao-xi

    2016-06-01

    Full Text Available Two different types of agglomerate and angular WC/Ni matrix composite coatings were deposited by laser cladding. The high temperature wear resistance of these composite coatings was tested with a ring-on-disc MMG-10 apparatus. The morphologies of the worn surfaces were observed using a scanning electron microscopy (SEM equipped with an energy dispersive spectroscopy (EDS for elemental composition. The results show that the high temperature wear resistance of the laser clad WC/Ni-based composite coatings is improved significantly with WC mass fraction increasing. The 60% agglomerate WC/Ni composite coating has optimal high temperature wear resistance. High temperature wear mechanism of 60% WC/Ni composite coating is from abrasive wear of low temperature into composite function of the oxidation wear and abrasive wear.

  4. "The good life" for demented persons living in nursing homes

    NARCIS (Netherlands)

    Kalis, A.|info:eu-repo/dai/nl/304823244; van Delden, J.J.M.; Schermer, M.H.N.

    2004-01-01

    Background: This study investigated which concepts regarding “the good life” are used in mission statements of nursing homes providing care for demented patients. Method: All 317 Dutch nursing homes caring for demented patients were asked to participate; of these, 69% responded. Their mission

  5. [Sleep disorders and sleep medicine in demented patients].

    Science.gov (United States)

    Mishima, Kazuo

    2012-01-01

    Demented elderly people often show severely fragmented sleep-waking patterns and are associated with disorganized circadian rhythm. Frequent nocturnal awakening and associated behavioral and psychological symptoms in demented people place a heavy burden on their families and care givers, and the development of an effective therapy is an important concern to health care practitioner and researchers. Although sleep disturbances in demented people could be classified into not only insomnia type but also irregular pattern type, differentiation has not yet been sufficiently practiced in a clinical setting. Demented people with irregular sleep pattern increase with progressive stage and are often insensitive to the usual pharmacotherapies for insomnia using benzodiazepines or antipsychotics. From the viewpoint of risk-benefit balance, chronotherapies such as artificial bright light or improvement of sleep hygiene could be useful and safety tools for sleep and behavioral problems in the demented elderly.

  6. Microstructure and hardness of WC-Co particle reinforced iron matrix surface composite

    OpenAIRE

    Zhang Peng; Zeng Shaolian; Zhang Zhiguo

    2013-01-01

    In this study, a high Cr cast iron surface composite material reinforced with WC-Co particles 2-6 mm in size was prepared using a pressureless sand mold infiltration casting technique. The composition, microstructure and hardness were determined by means of energy dispersive spectrometry (EDS), electron probe microanalysis (EPMA), scanning electron microscope (SEM) and Rockwell hardness measurements. It is determined that the obtained composite layer is about 15 mm thick with a WC-Co particle...

  7. "The good life" for demented persons living in nursing homes.

    Science.gov (United States)

    Kalis, Annemarie; van Delden, Johannes J M; Schermer, Maartje H N

    2004-12-01

    This study investigated which concepts regarding "the good life" are used in mission statements of nursing homes providing care for demented patients. All 317 Dutch nursing homes caring for demented patients were asked to participate; of these, 69% responded. Their mission statements were qualitatively analyzed on content. Whether different types of nursing home differed significantly in the content of their mission statements was investigated by means of chi2 analyses. Six main concepts were found that are considered important for a good life: 1) autonomy and freedom, 2) individuality and lifestyle, 3) relationships and social networks, 4) warmth and safety and familiarity, 5) developing capacities and giving meaning to life and 6) subjective experience and feelings of well-being. It was found that mission statements specifically developed for demented patients attach less importance to the concepts 1) autonomy and freedom and 2) individuality and lifestyle, than mission statements which are also aimed at non-demented residents. Most mission statements turned out to be highly eclectic in content. Nursing homes with a separate statement for demented residents seem to acknowledge the special position of demented residents and the tension between dementia and the ideal of autonomy. Although the eclecticism found in mission statements is understandable, a coherent view on the good life for demented residents should aim for a sound internal structure, and make choices between values. Only then can mission statements provide real guidance for everyday care.

  8. Neuropsychological assessment of patients with dementing illness.

    Science.gov (United States)

    Fields, Julie A; Ferman, Tanis J; Boeve, Bradley F; Smith, Glenn E

    2011-11-01

    Neuropsychological assessment has a distinct role in the detection and monitoring of cognitive and functional changes associated with dementing illness. Molecular, structural and functional neuroimaging studies have advanced our understanding of the anatomy and physiology underlying neurodegenerative disease; however, the overlap in pathological features of different dementia-associated diseases limits the information that can be obtained by these methods. Incorporation of information obtained from multiple sources can help to increase diagnostic and prognostic accuracy. Neuropsychological test findings provide unique value as biomarkers of dementia, as differentiators of disease topography and in the estimation of disease risk and trajectory. However, psychometric test properties--such as construct validity, stability and the use of appropriate norms--must be understood, because they influence both the application of neuropsychological tests and the interpretation of their results. Finally, measurement of cognitive strengths and weaknesses in patients at risk of dementia can be helpful to predict changes in functional abilities, design appropriate and effective interventions, and assist family and health-care providers in the planning of the patient's future care needs. This Review describes the key characteristics of neuropsychological testing in the assessment of patients at risk of dementia.

  9. Learning from other lands. Caring for elderly demented Koreans.

    Science.gov (United States)

    Lee, H; Kim, S; You, K S

    1997-09-01

    The aims of the study reported here were to describe the socio-demographic characteristics of caregivers of demented elders in Korea and their care recipients and to compare the positive and negative meanings and outcomes of the caregiving experiences of caregivers who had admitted their elderly demented relative to a nursing home (G1: n = 24) and caregivers still caring for their elderly demented relatives at home (G2: n = 30). Most caregivers were female (80%), married (89%), and related to the care receiver as daughter-in-law (39%), daughter (22%), wife (15%), son (13%), or neighbor (6%). Social class differences were found between the home care and nursing home groups: the upper classes were significantly more likely to have placed their demented elder in a nursing home, whereas the low social classes were more likely to keep taking care of their demented elder at home instead of placing them in a nursing home. Caregivers who had admitted their relative to a nursing home (G1) reported significantly more difficulties from disturbed sleep, disrupted children's studies, and limited personal life when they were caring for the elder at home (p care group (G2) had significantly greater satisfaction in serving as a model for their children and practicing religion (p care receiver than those who have placed their demented elder in a nursing home, although the difference in this case was not significant.

  10. WC/Ni bronze composite material formation by combined methods of laser cladding and cold spraying

    Science.gov (United States)

    Ryashin, N. S.; Malikov, A. G.; Gulyaev, I. P.; Klinkov, S. V.; Kosarev, V. F.; Orishich, A. M.

    2016-10-01

    Formation of composite material containing anti-friction bronze CuAl8.5Fe4Ni5Mn1.5 and reinforced by inner bulk profiled frame of WC/Ni was considered. Combined methods of laser cladding and cold spraying were used. Reinforced cold spraying copper-bronze blend deposits on profiled frames of WC/Ni produced by laser cladding were obtained. Dependence of bronze weight concentration in cold spraying copper-bronze deposit on bronze weight part in powder blend was analyzed. Results of non-contact profiling of reinforcing WC/Ni frame, EDS analysis and microhardness tests of obtained reinforced copper-bronze-WC/Ni composites were presented.

  11. Effect of Load on Friction-Wear Behavior of HVOF-Sprayed WC-12Co Coatings

    Science.gov (United States)

    Yifu, Jin; Weicheng, Kong; Tianyuan, Sheng; Ruihong, Zhang; Dejun, Kong

    2017-07-01

    A WC-12Co coating was sprayed on AISI H13 hot work mold steel using a high-velocity oxygen fuel. The morphologies, phase compositions, and distributions of chemical elements of the obtained coatings were analyzed using a field emission scanning electron microscope, x-ray diffraction, and energy-dispersive spectroscope (EDS), respectively. The friction-wear behaviors under different loads were investigated using a reciprocating wear tester; the morphologies and distributions of the chemical elements of worn tracks were analyzed using a SEM and its configured EDS, respectively. The results show the reunited grains of WC are held together by the Co binder; the primary phases of the coating are WC, Co, and a small amount of W2C and W, owing to the oxidation and decarburization of WC. Inter-diffusion of Fe and W between the coating and the substrate is shown, which indicates a good coating adhesion. The values of the average coefficient of friction under the loads of 40, 80, and 120 N are 0.29, 0.31, and 0.49, respectively. The WC grains are pulled out of the coating during the sliding wear test, but the coating maintains its integrity, suggesting that the coating is intact and continuously protects the substrate from wearing.

  12. Performance characterization of Ni60-WC coating on steel processed with supersonic laser deposition

    Directory of Open Access Journals (Sweden)

    Fang Luo

    2015-03-01

    Full Text Available Ni60-WC particles are used to improve the wear resistance of hard-facing steel due to their high hardness. An emerging technology that combines laser with cold spraying to deposit the hard-facing coatings is known as supersonic laser deposition. In this study, Ni60-WC is deposited on low-carbon steel using SLD. The microstructure and performance of the coatings are investigated through SEM, optical microscopy, EDS, XRD, microhardness and pin-on-disc wear tests. The experimental results of the coating processed with the optimal parameters are compared to those of the coating deposited using laser cladding.

  13. Cognitive testing in non-demented Turkish immigrants

    DEFF Research Database (Denmark)

    Nielsen, T. Rune; Vogel, Asmus M.; Gade, Anders

    2012-01-01

    of non-demented community-dwelling Turkish immigrants was recruited from the greater Copenhagen area. All participants completed a structured interview regarding demographic, physical and mental health status, as well as measures of depression and acculturation, and cognitive testing with the RUDAS...

  14. Structure of nanocrystalline WC-10%Co powder

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Nanostructured WC-Co powders obtained by mechanical milling were investigated by combination of X-ray diffraction (XRD) and high-resolution transmission electron microscopy (HRTEM) techniques. Rietveld analysis indicates that the experimental XRD patterns cannot be satisfactorily explained with the hexagonal WC structure. HRTEM image analysis shows that in the as-milled nanostructured powder, many WC grains contain stacking faults lying on the plane {10*0}. Analysis of phase images show that these defects are nearly periodically ordered along the [10*0] direction. Based on these observations, a structural model was proposed for the WC grains with ordered stacking faults, which is in fact equivalent to a superstructure of WC with space group Amm2. When this model describing the faulted fraction of WC is introduced together with the normal WC structure (space group P6—m2) into the Rietveld refinement, a much better agreement between the calculated and experimental XRD profiles was obtained. This study allows to obtain the lattice parameters, grain size, microstrain and other structural information on the as-milled powders.

  15. Effect of high energy milling on the microstruture and properties of wc-ni composite

    Directory of Open Access Journals (Sweden)

    Camila dos Santos Torres

    2010-09-01

    Full Text Available Hard metal is a composite material used in several areas of machining, mining and construction. It can be applied directly on oil and gas drilling equipment components. The main objective of this work was to apply a high energy milling technique to produce the WC-Ni composite and study the effects of milling time in the material properties. The milling of hard metal WC-20Ni, was performed for milling times of 1, 2, 4, 8, 16, 32 and 64 hours. The starting powders were characterized by laser sedigraphy, SEM and EDS. Microstrutural analysis of the sintered samples was performed by optical microscopy, microhardness and density by Archimedes. The best results for the WC-20%Ni composite were achieved for 8 hours milling, where the density and hardness reached 97.09% and 1058 ± 54 HV, respectively, after sintering.

  16. Natural short sleeper

    Science.gov (United States)

    ... pubmed/20120619 . Landolt H-P, Kijk D-J. Genetics and genomic basis of sleep in healthy humans. In: Kryger M, Roth T, Dement WC, eds. Principles and Practice of Sleep Medicine. 6th ed. Philadelphia, ...

  17. Study on WC dispersion-strengthened copper

    Institute of Scientific and Technical Information of China (English)

    WANG Mengjun; ZHANG Liyong; LIU Xinyu

    2004-01-01

    Dispersion-strengthened copper (DSC) with WC as dispersoid was prepared by means of mechanical alloying (MA) following the traditional powder metallurgy (P/M) route. Influence of WC content on the properties of material was discussed in detail, and result shows that when the volume fraction of WC is 1.6%, the material achieves the best overall property, and a little more particle addition led to a less superior property owing to occurrence of particle agglomeration The as-sintered composite was designed to undergo a deformation of 75%. It is proved that appropriate deformation is helpful to attain a higher density and consequently better properties. Deformed material was then exposed to elevated temperature to test its effect on material. Annealing for 1 h at 1173K caused material to recover quite completely, but no obvious recrystallization was observed. It's supposed the particles handicaps motion of dislocations and material demonstrates good retention of strength with substantial improvement in elongation.

  18. Noname眼中的WC3L

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    First Speaking第一次说的话"My name is Elroy Pinto aka fnatic.Noname,I am the manager for fnatic.WC3 and head of WC3 on fnatic.com.I have worked on several international projects such as WCReplays.com which is a big American community website.I have also been a manager and head of WC3 for MYM.International back in 2005.Until 2007 I was with MYM until I switched to fnatic.My first venture was a content writer and admin on a national website which soon came to an end.But in my time as a manager I have

  19. Effects of WC Particle Size and Co Content on the Graded Structure in Functionally Gradient WC-Co Composites

    Directory of Open Access Journals (Sweden)

    Yuan Yigao

    2016-01-01

    Full Text Available Functionally gradient WC-Co composites having a Co depleted surface zone and not comprising the h phase can be manufactured via carburizing process. During carburizing, besides carburizing process parameters, the microstructural parameters of WC-Co materials, such as WC grain size and Co content, also have significant influences on the formation of Co gradient structure. In this study, the effects of WC particle size and Co content on the gradient structure within gradient hardmetals have been studied, based on a series of carburizing experiments of WC-Co materials with different WC particle sizes and cobalt contents. The results show that both the thickness and the amplitude of the gradients within gradient WC-Co materials increase with increasing initial WC particle size and Co content of WC-Co alloys. The reason for this finding is discussed.

  20. Metallographic Analyses of Laser Cladded WC-Ni and WC-Co Hard-facing Metals

    Institute of Scientific and Technical Information of China (English)

    HK Chikwanda; M Chiremba; C Van Rooyen

    2004-01-01

    Laser cladding is performed to improve the surface properties of metallic machine components. Extensive work is being conducted to investigate the relationships among the cladding parameters, clad powder characteristics and the quality of the clad layer. This work presents some of the metallographic analyses results of WC -Ni and WC-Co clad layers. The clad layers are characterised with non-uniform carbide particles, mostly WC imbedded in a more ductile matrix.The transition from the clad layer to the substrate metal had a distinct dilution zone. The ratio of this zone to the clad height was in the range of 10 -12% and this still needs to be refined.

  1. MICROSTRUCTURAL STUDY OF FAILURE PHENOMENA IN WC 94%-Co 6% HARD METAL ALLOY TIPS OF RADIAL PICKS

    Directory of Open Access Journals (Sweden)

    Sakuntala Nahak

    2017-03-01

    Full Text Available An excellent combination of hardness, strength, stiffness and high melting point has proved the WC-Co as an ideal material for tools which are used for metal cutting, coal mining, oil drilling, etc. The ongoing research in WC-Co is focussed on enhancing its wear resistant properties as much as possible. For the purpose, many attempts have been made to study the tribological behaviour of WC-Co for a long time. Researchers have used various grades of WC-Co in different working environment and accordingly they have characterized the wear phenomena involved in it. In this direction of research, the present paper makes an attempt to understand various wear behaviours in WC 94%-Co 6% hard metal alloy. WC-Co was used as a tip of the coal cutting tool, named, radial pick. Two radial picks have been taken for critical analysis through field emission scanning electron microscopy (FESEM attached with energy dispersive X-ray spectroscopy (EDS. In this work, the failure behaviours in the tools have been divided into five categories: (1 Abrasion on individual grain; (2 Corrosion in carbide grains; (3 Fragmentation and removal of WC grains; (4 Pores in WC grains; and (5 Coal and rock embedding. The most possible reasons behind each failure phenomenon have been explained comprehensively with the help of high resolution microscopic images. However, it is usually observed that, initially, the tool gets minor cracks due to sudden impact. These cracks provide a path to the rock and coal particles to get entrenched inside the microstructure of cemented carbide. Finally, the intermixed external elements degrade the binder content (i.e. cobalt and the tool becomes useless.

  2. Microstructure and hardness of WC-Co particle reinforced iron matrix surface composite

    Directory of Open Access Journals (Sweden)

    Zhang Peng

    2013-11-01

    Full Text Available In this study, a high Cr cast iron surface composite material reinforced with WC-Co particles 2-6 mm in size was prepared using a pressureless sand mold infiltration casting technique. The composition, microstructure and hardness were determined by means of energy dispersive spectrometry (EDS, electron probe microanalysis (EPMA, scanning electron microscope (SEM and Rockwell hardness measurements. It is determined that the obtained composite layer is about 15 mm thick with a WC-Co particle volumetric fraction of ~38%. During solidification, interface reaction takes place between WC-Co particles and high chromium cast iron. Melting and dissolving of prefabricated particles are also found, suggesting that local Co melting and diffusion play an important role in promoting interface metallurgical bonding. The composite layer is composed of ferrite and a series of carbides, such as (Cr, W, Fe23C6, WC, W2C, M6C and M12C. The inhomogeneous hardness in the obtained composite material shows a gradient decrease from the particle reinforced metal matrix composite layer to the matrix layer. The maximum hardness of 86.3 HRA (69.5 HRC is obtained on the particle reinforced surface, strongly indicating that the composite can be used as wear resistant material.

  3. Characterization of WC-10Ni HVOF Coating for Carbon Steel Blade

    Science.gov (United States)

    Ahmad, N. A.; Kamdi, Z.; Mohamad, Z.; Omar, A. S.; Latif, N. Abdul; Tobi, A. L. Mohd

    2017-01-01

    High Velocity Oxy-Fuel, HVOF is a depositing methods of a material layer over a base metal or substrate with characteristics of high flame velocity and moderate temperature. Where, tungsten carbide, WC cermet HVOF coatings is widely used to protect machine components from wear and corrosion. The main purpose of this present paper is to characterize the WC-10Ni coating deposited by HVOF thermal spray onto a carbon steel blade. The morphology and chemical composition of the coating were characterized by Scanning Electron Microstructure (SEM), electron dispersive spectrometer (EDS), and X-ray diffraction (XRD). The hardness test was carried out by using Vickers micro-hardness tester with loads of 490.3 mN (HV0.05). From XRD results, no sharp nickel peak was identified and has been replaced by a hump which indicate the amorphous Ni. The major crystalline phases were compounds WC, W2C and metallic phase of W. The WC-10Ni coating shows high hardness with low porosity distribution.

  4. Super hard WC-Cr composite coatings. An approach to potential wear applications

    Energy Technology Data Exchange (ETDEWEB)

    Sancakoglu, Orkut; Celik, Erdal [Dokuz Eylul Univ., Izmir (Turkey). Dept. of Metallurgy and Materials Engineering

    2016-11-01

    In this study, submicron (APS = 200 nm) tungsten carbide (WC) ceramic particles were co-deposited with chromium metal (Cr) via electro-co-deposition system to fabricate WC-Cr metal matrix composite coatings. Instead of traditional electrodeposition cells, a new system was designed and coatings were fabricated using this system. Phase identifications of the coatings were performed by X-ray diffractometry (XRD) and surface morphologies were investigated using energy dispersive X-ray spectroscopy (EDS) with attached scanning electron microscope (SEM). Hardness values of the coatings were performed under 980.7 mN applied load using a microhardness tester. It was concluded that WC ceramic particles were physically adsorbed on the cathode surface and formed a composite structure with metal Cr and co-deposition of submicron sized ceramic particles with metals via electrodeposition system was strictly successful. In addition, with respect to the reference coatings, WC reinforced composite coatings depict an increased hardness up to twice its value. Frequency, as a parameter of pulse current, is determined as an effective parameter in co-deposition.

  5. Association between quality of life of demented patients and professional knowledge of care workers.

    Science.gov (United States)

    Kazui, Hiroaki; Harada, Kazuyoshi; Eguchi, Yoko S; Tokunaga, Hiromasa; Endo, Hidetoshi; Takeda, Masatoshi

    2008-03-01

    Professional knowledge about dementia and care methods is necessary for the appropriate care of demented people. In this study, the quality of life of 91 demented people staying at 12 care institutions was evaluated with the Quality of Life Questionnaire for Dementia (QOL-D). The amount of professional knowledge was evaluated in 140 staff members who took care of the patients using the professional knowledge test (PKT), and the mean PKT score was calculated for each institution (professional knowledge of institution). A positive significant correlation was observed between the QOL-D score and the professional knowledge of institution. The correlation remained significant when age, sex, and severity of dementia of demented patients were partialled out. This result indicated that the quality of life of demented people was better at institutions with staff members having more professional knowledge, indicating the importance of education of staff members and the possibility that such education improves the quality of life of the demented people.

  6. On the preparation of fine V8 C7-WC and V4 C 3-WC powders

    CSIR Research Space (South Africa)

    Osborne, C

    1997-01-01

    Full Text Available The aim of this work was to produce V8 C7-WC and V4 C 3-WC powders with grain size between 1 and 2mu-m, as a first stage of the preparation of fine grained WC-VC-Co hardmetal. V8 C7-WC powder was produced via two routes: starting from preformed V8 C7...

  7. Nano- and microcrystalline diamond deposition on pretreated WC-Co substrates: structural properties and adhesion

    Science.gov (United States)

    Fraga, M. A.; Contin, A.; Rodríguez, L. A. A.; Vieira, J.; Campos, R. A.; Corat, E. J.; Trava Airoldi, V. J.

    2016-02-01

    Many developments have been made to improve the quality and adherence of CVD diamond films onto WC-Co hard metal tools by the removing the cobalt from the substrate surface through substrate pretreatments. Here we compare the efficiency of three chemical pretreatments of WC-Co substrates for this purpose. First, the work was focused on a detailed study of the composition and structure of as-polished and pretreated substrate surfaces to characterize the effects of the substrate preparation. Considering this objective, a set of WC-9% Co substrates, before and after pretreatment, was analyzed by FEG-SEM, EDS and x-ray diffraction (XRD). The second stage of the work was devoted to the evaluation of the influence of seeding process, using 4 nm diamond nanoparticles, on the morphology and roughness of the pretreated substrates. The last and most important stage was to deposit diamond coatings with different crystallite sizes (nano and micro) by hot-filament CVD to understand fully the mechanism of growth and adhesion of CVD diamond films on pretreated WC-Co substrates. The transition from nano to microcrystalline diamond was achieved by controlling the CH4/H2 gas ratio. The nano and microcrystalline samples were grown under same time at different substrate temperatures 600 °C and 800 °C, respectively. The different substrate temperatures allowed the analysis of the cobalt diffusion from the bulk to the substrate surface during CVD film growth. Furthermore, it was possible to evaluate how the coating adhesion is affected by the diffusion. The diamond coatings were characterized by Raman spectroscopy, XRD, EDS, FEG-SEM, atomic force microscope and 1500 N Rockwell indentation to evaluate the adhesion.

  8. Critical Damage Analysis of WC-Co Tip of Conical Pick due to Coal Excavation in Mines

    Directory of Open Access Journals (Sweden)

    Saurabh Dewangan

    2015-01-01

    Full Text Available WC-Co based tools are widely used in the field of coal and rock excavation because of their unique combination of strength, hardness, and resistance to abrasive wear. Conical pick is one of the coal cutting tools. The tip of the pick is made of WC-Co material. As coal and rock are heterogeneous elements, they pose various constraints during excavation. As a result the tools wear out during the process. Other parameters like cutting techniques, tool orientation, and environmental conditions also affect the tool significantly. The wearing phenomenon greatly reduces the service life of the tools and thereby cuts down the production rate. To prevent such wearing process, it is important to investigate the different wear mechanisms in WC-Co. Simultaneously, there has to be an ongoing endeavour for the development of better quality WC-Co. This paper focuses on different wear mechanisms in a conical pick which has been used in a continuous miner machine for coal cutting. The worn out surface has been observed by using FE-SEM (field emission scanning electron microscopy and EDS (energy dispersive X-ray spectroscopy. The mechanisms, namely, coal/rock intermixing, cracking and crushing of WC grains, and adhesion of rock particles, have been predominantly investigated in this study. A little indication of corrosive decay in the WC grain has also been reported. The EDS has detected material concentration in a selected area or point of the worn-out surface. The spectrograph confirms the presence of coal/rock materials. Elements such as W, C, Ca, K, O, and Co have been mainly found in different concentrations at different positions.

  9. Study on in-situ WC particles/tungsten wire reinforced iron matrix composites under electromagnetic field

    Directory of Open Access Journals (Sweden)

    Niu Libin

    2010-05-01

    Full Text Available By applying electromagnetic field to a system consisting of tungsten wires and grey cast iron melt, the grey cast iron matrix composite reinforced by either in-situ WC particles or the combination of in-situ WC particles and the residual tungsten wire was obtained. By means of differential thermal analysis (DTA, the pouring temperature of iron melt was determined at 1,573 K. The microstructures of the composites were analyzed by using of X-ray diffraction (XRD, scanning electron microscopy (SEM equipped with an energy dispersive spectrum (EDS and pin-on-disc abrasive wear test. The obtained results indicated that, with the enhancing frequency of electromagnetic field, the amount of in-situ WC particles gradually increases, leading to continuous decrease of the residual tungsten wires. When the electromagnetic field frequency was up to 4 kHz, tungsten wires reacted completely with carbon atoms in grey cast iron melt, forming WC particals. The electromagnetic field appeared to accelerate the elemental diffusion in the melt, to help relatively quick formation of a series of small Fe-W-C ternary zones and to improve the kinetic condition of in-situ WC fabrication. As compared with the composite prepared without the electromagnetic field, the composite fabricated at 4 kHz presented good wear resistance.

  10. Metaliographic Analyses of Laser Cladded WC-Ni and WC-Co Hard-facing Metals

    Institute of Scientific and Technical Information of China (English)

    HKChikwanda; MChiremba; CVanRooyen

    2004-01-01

    Laser cladding is performed to improve the surface properties of metallic machine components. Extensive work is being conducted to investigate the relationships among the cladding parameters, clad powder characteristics and the quality of the clad layer. This work presents some of the metallographic analyses results of WC-Ni and WC-Co clad layers. The clad layers are chayacterised with non-uniform carbide par[icles, mostly WC imbedded in a more ductile matrix. The transition from the clad layer to the subslxate metal had a distinct dilution zone. The ratio of this zone to the clad height was in the range of 10-12% and this still needs robe refined.

  11. Awareness of expressivity deficits in non-demented Parkinson disease.

    Science.gov (United States)

    Mikos, Ania E; Springer, Utaka S; Nisenzon, Anne N; Kellison, Ida L; Fernandez, Hubert H; Okun, Michael S; Bowers, Dawn

    2009-07-01

    A masked facial expression, one of the hallmark features of Parkinson disease (PD), can form the basis for misattributions by others about a patient's mood or interest levels. Reports of preserved intensity of internal emotional experience in PD participants raise the question of whether patients are aware of their outward expressivity levels. The aim of the present study was to determine whether PD participants exhibit deficits in overall emotional expressivity, and if so, whether they are aware of these deficits. We evaluated 37 non-demented PD participants and 21 comparison participants using the Berkeley Expressivity Questionnaire (BEQ). To examine awareness of emotional expressivity, we compared participant self-ratings of their own expressivity to ratings made by family members or close friends. Participants also completed questionnaires regarding depression and apathy and underwent motor examination and cognitive screening. PD participants' self-ratings of emotional expressivity were significantly lower than comparison participants' self-ratings. Even so, the PD participants viewed themselves as experiencing equivalent levels of emotional intensity to comparison participants, based on analysis of the BEQ subscales. Informant and PD participant self-ratings did not differ, indicating that PD participants accurately appraise the extent of their reduced expressivity. These findings suggest that anosognosia for emotional expressivity is not a prominent feature of nondemented Parkinson disease. Importantly, PD participants are aware of their reduced expressivity and report experiencing emotions as intensely as comparison participants. These findings highlight the view that diminished emotional expressivity in PD should not be mistaken for decreased subjective emotional experience.

  12. Inform@ed space

    DEFF Research Database (Denmark)

    Bjerrum, Peter; Olsen, Kasper Nefer

    2001-01-01

    Inform@ed space Sensorial Perception And Computer Enchancement - bidrag til Nordisk Arkitekturforskningsforenings IT-konference, AAA april 2001.......Inform@ed space Sensorial Perception And Computer Enchancement - bidrag til Nordisk Arkitekturforskningsforenings IT-konference, AAA april 2001....

  13. Gait analysis in demented subjects: Interests and perspectives

    Directory of Open Access Journals (Sweden)

    Olivier Beauchet

    2008-03-01

    Full Text Available Olivier Beauchet1, Gilles Allali2, Gilles Berrut3, Caroline Hommet4, Véronique Dubost5, Frédéric Assal21Department of Geriatrics, Angers University Hospital, France; 2Department of Neurology, Geneva University Hospital, France; 3Department of Geriatrics, Nantes University Hospital, France; 4Department of Internal Medicine and Geriatrics, Tours University Hospital, France; 5Department of Geriatrics, Dijon University Hospital, FranceAbstract: Gait disorders are more prevalent in dementia than in normal aging and are related to the severity of cognitive decline. Dementia-related gait changes (DRGC mainly include decrease in walking speed provoked by a decrease in stride length and an increase in support phase. More recently, dual-task related changes in gait were found in Alzheimer’s disease (AD and non-Alzheimer dementia, even at an early stage. An increase in stride-to-stride variability while usual walking and dual-tasking has been shown to be more specific and sensitive than any change in mean value in subjects with dementia. Those data show that DRGC are not only associated to motor disorders but also to problem with central processing of information and highlight that dysfunction of temporal and frontal lobe may in part explain gait impairment among demented subjects. Gait assessment, and more particularly dual-task analysis, is therefore crucial in early diagnosis of dementia and/or related syndromes in the elderly. Moreover, dual-task disturbances could be a specific marker of falling at a pre-dementia stage.Keywords: gait, prediction of dementia, risk of falling, older adult

  14. The kinematical behavior of Galactic PNe with [WC] central star

    CERN Document Server

    Rechy-García, J S; García-Rojas, \\and Jorge

    2011-01-01

    High resolution spectroscopic data of a large sample of galactic planetary nebulae with [WC] central stars ([WC]PNe) are analyzed to determine their kinematical behavior. Their heliocentric velocities have been determined with a precision better than a few km/s. Distances obtained from the literature are used to derive the peculiar velocities of the objects.

  15. Direct laser sintered WC-10Co/Cu nanocomposites

    Science.gov (United States)

    Gu, Dongdong; Shen, Yifu

    2008-04-01

    In the present work, the direct metal laser sintering (DMLS) process was used to prepare the WC-Co/Cu nanocomposites in bulk form. The WC reinforcing nanoparticles were added in the form of WC-10 wt.% Co composite powder. The microstructural features and mechanical properties of the laser-sintered sample were characterized by X-ray diffraction (XRD), atomic force microscope (AFM), scanning electron microscope (SEM), energy dispersive X-ray spectroscope (EDX), and nanoindentation tester. It showed that the original nanometric nature of the WC reinforcing particulates was well retained without appreciable grain growth after laser processing. A homogeneous distribution of the WC reinforcing nanoparticles with a coherent particulate/matrix interfacial bonding was obtained in the laser-sintered structure. The 94.3% dense nanocomposites have a dynamic nanohardness of 3.47 GPa and a reduced elastic modulus of 613.42 GPa.

  16. Annual Performance Evaluation of a Pair of Energy Efficient Houses (WC3 and WC4) in Oak Ridge, TN

    Energy Technology Data Exchange (ETDEWEB)

    Biswas, Kaushik [ORNL; Christian, Jeffrey E [ORNL; Gehl, Anthony C [ORNL; Jackson, Roderick K [ORNL; Boudreaux, Philip R [ORNL

    2012-04-01

    Beginning in 2008, two pairs of energy-saver houses were built at Wolf Creek in Oak Ridge, TN. These houses were designed to maximize energy efficiency using new ultra-high-efficiency components emerging from ORNL s Cooperative Research and Development Agreement (CRADA) partners and others. The first two houses contained 3713 square feet of conditioned area and were designated as WC1 and WC2; the second pair consisted of 2721 square feet conditioned area with crawlspace foundation and they re called WC3 and WC4. This report is focused on the annual energy performance of WC3 and WC4, and how they compare against a previously benchmarked maximum energy efficient house of a similar footprint. WC3 and WC4 are both about 55-60% more efficient than traditional new construction. Each house showcases a different envelope system: WC3 is built with advanced framing featured cellulose insulation partially mixed with phase change materials (PCM); and WC4 house has cladding composed of an exterior insulation and finish system (EIFS). The previously benchmarked house was one of three built at the Campbell Creek subdivision in Knoxville, TN. This house (CC3) was designed as a transformation of a builder house (CC1) with the most advanced energy-efficiency features, including solar electricity and hot water, which market conditions are likely to permit within the 2012 2015 period. The builder house itself was representative of a standard, IECC 2006 code-certified, all-electric house built by the builder to sell around 2005 2008.

  17. Electrochemical properties of mixed WC and Pt-black powders

    Directory of Open Access Journals (Sweden)

    MAJA D. OBRADOVIC

    2008-12-01

    Full Text Available The electrochemical characteristics of a mixture of Pt-black and WC powders and its catalytic activity for methanol and formic acid oxidation were investigated in acid solution. XRD and AFM measurements revealed that the WC powder employed for the investigation was a single-phase material consisting of crystallites/spherical particles of average size of about 50 nm, which were agglomerated into much larger particles. Cyclic voltammetry showed that the WC underwent electrochemical oxidation, producing tungstate species. In the case of the mixed Pt + WC powders, the tungstate species were deposited on the Pt as a thin film of hydrous tungsten oxide. Enhanced hydrogen intercalation in the hydrous tungsten oxide was observed and it was proposed to be promoted in mixed powders by the presence of hydrogen adatoms on bare Pt sites. The determination of Pt surface area in the Pt + WC layer by stripping of underpotentially deposited Cu revealed that the entire Pt surface was accessible for underpotential deposition of Cu. Investigation of the electrochemical oxidation of methanol and formic acid on Pt + WC and pure Pt layers did not indicate electrocatalytic promotion due to the presence of WC.

  18. The Nature of Bonding in WC and WN

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The nature of bonding in the title compounds has been studied by using CASSCF and FOCl techniques. The ground states of WC and WN are found to be 3Δ and 4∑- state arising primarily from:...1σ2σ21π41δ13σ1 and ...1σ2σ21π41δ23σ1 configuration respectively. WC shows a strong character of covalent bond while WN have obvious character of ionic bond and the dissociation energy of WN is larger than that of WC (6.15 and 5.41 eV respective).

  19. Blood Concentrations of Homocysteine and Methylmalonic Acid among Demented and Non-Demented Swedish Elderly with and without Home Care Services and Vitamin B12 Prescriptions

    Directory of Open Access Journals (Sweden)

    Nils-Olof Hagnelius

    2012-09-01

    Full Text Available Background and Aims: Total plasma homocysteine (tHcy has been suggested as a risk factor of dementia. Our aim was to investigate potential differences in tHcy status in relation to the prescription of vitamin B12 and dementia diagnosis. We examined whether vitamin B12 prescriptions, a family history of dementia, or the need for home care service might be associated with tHcy values. Methods: A cross-sectional monocenter study comprising 926 consecutive subjects attending our Memory Care Unit was conducted. Results: Demented subjects being prescribed vitamin B12 had higher serum vitamin B12 (p = 0.025 but also higher tHcy (p 12 prescriptions. tHcy levels were significantly higher in non-demented subjects receiving home care service (p = 0.007. This group also had lower serum albumin (dementia: p 12 prescriptions (dementia with/without vitamin B12 prescription: p = 0.561; non-dementia with/without vitamin B12 prescription: p = 0.710. Conclusion: Despite vitamin B12 prescriptions, demented subjects had higher tHcy and methylmalonate values. The elevated metabolite values could not be explained by differences in renal function. Thus, elderly subjects on vitamin B12 prescription appear to have unmet nutritional needs.

  20. Verbal Fluency Performance in Patients with Non-demented Parkinson’s Disease

    Directory of Open Access Journals (Sweden)

    Hooshang Dadgar

    2013-03-01

    Full Text Available Objective: While Parkinson’s disease (PD has traditionally been defined by motor symptoms, many researches have indicated that mild cognitive impairment is common in non-demented PD patients. The purpose of this study was to compare verbal fluency performance in non-demented Parkinson’s disease patients with healthy controls.Method: In this cross-sectional study thirty non-demented Parkinson’s disease patients and 30 healthy controls, matched by age, gender and education, were compared on verbal fluency performance. Verbal fluency was studied with a Phonemic Fluency task using the letters F, A, and S, a semantic fluency task using the categories animals and fruits. The independent t-test was used for data analysis.Results: Overall, participants generated more words in the semantic fluency task than in the phonemic fluency task. Results revealed significant differences between patients and controls in semantic fluency task (p<.05. In addition, PD patients showed a significant reduction of correctly generated words in letter fluency task. The total number of words produced was also significantly lower in the PD group (p<.05.Conclusion: Verbal fluency disruption is implied in non-demented PD patients in association with incipient cognitive impairment.

  1. Nursing-care dependency : Development of an assessment scale for demented and mentally handicapped patients

    NARCIS (Netherlands)

    Dijkstra, Ate; Buist, Girbe; Dassen, T

    1996-01-01

    This article describing the first phase in the development of an assessment scale of nursing-care dependency (NCD) for Dutch demented and mentally handicapped patients focuses on the background to the study and the content validation of the nursing-care dependency scale. The scale aims to

  2. Wear behaviors of HVOF sprayed WC-12Co coatings by laser remelting under lubricated condition

    Science.gov (United States)

    Dejun, Kong; Tianyuan, Sheng

    2017-03-01

    A HVOF (high velocity oxygen fuel) sprayed WC-12Co coating was remelted with a CO2 laser. The surface-interface morphologies and phases were analyzed by means of SEM (scanning electron microscopy), and XRD (X-ray diffraction), respectively. The friction and wear behaviors of WC-12Co coating under the dry and lubricated conditions were investigated with a wear test. The morphologies and distributions of chemical elements on worn scar were analyzed with a SEM, and its configured EDS (energy diffusive spectrometer), respectively, and the effects of lubricated condition on COFs (coefficient of friction) and wear performance were also discussed. The results show that the adhesion between the coating and the substrate is stronger after laser remetling (LR), in which mechanical bonding, accompanying with metallurgical bonding, was found. At the load of 80 N, the average COF under the dry and lubricated friction conditions is 0.069, and 0.052, respectively, the latter lowers by 23.3% than the former, and the wear rate under the lubricated condition decreases by 302.3% than that under the dry condition. The wear mechanism under the dry and lubrication conditions is primarily composed of abrasive wear, cracking, and fatigue failure.

  3. Tribological Properties of WC-12Co/NiCrAl Composite Coating Prepared by Plasma Spraying%等离子喷涂WC-12Co/NiCrAl复合涂层的摩擦磨损特性

    Institute of Scientific and Technical Information of China (English)

    郭华锋; 田宗军; 黄因慧

    2014-01-01

    以NiCrAl涂层为粘结层,用等离子喷涂工艺在TC4钛合金表面制备了WC-12Co/NiCrAl复合涂层.通过扫描电镜(SEM)、能谱仪(EDS)、X射线衍射仪(XRD)和显微硬度仪等手段分析了涂层微观形貌、化学成分和显微硬度,并用磨损试验考察了WC-12Co/NiCrAl复合涂层的摩擦磨损特性.结果表明:WC-12Co涂层表面未熔颗粒较多,涂层截面孔隙率为10.2%;WC发生部分分解,出现W2C、Co6 W6C等新相;涂层与基体结合界面为机械结合十局部微冶金结合方式;显微硬度为双态Weibull分布,呈现不同位置结构的差异化.WC-12Co涂层表现出良好的减摩及耐磨性能,同载荷下摩擦因数低于基体,磨损失重为基体的1/10,磨粒磨损是其主要磨损机制.

  4. Nanocrystalline WC with non-toxic Fe-Mn binder

    Energy Technology Data Exchange (ETDEWEB)

    Siemiaszko, Dariusz [Military University of Technology, Department of Advanced Technology and Chemistry, ul. Gen. S. Kaliskiego 2, 00-908 Warsaw (Poland); Rosinski, Marcin; Michalski, Andrzej [Warsaw University of Technology, Department of Materials Science and Engineering, Woloska 141, 02-507 Warsaw (Poland)

    2010-05-15

    Cemented carbides, based on the tungsten carbide (WC), are very popular and useful in an industry. The most important metal us as a binder in this kind of materials is cobalt. It has many advantages as a binder: very good wettability, favourable solubility with WC and thermal conductivity similar to WC. However, cost of cobalt is very high because of its low natural resources. Cobalt is not also neutral for health. It is known as an allergen and same research shown that it could cause a cancer. This paper presents results of sintering the tungsten carbides with Fe-Mn alloys as the binders. (copyright 2010 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  5. Reactive Sintering of Bimodal WC-Co Hardmetals

    Directory of Open Access Journals (Sweden)

    Marek Tarraste

    2015-09-01

    Full Text Available Bimodal WC-Co hardmetals were produced using novel technology - reactive sintering. Milled and activated tungsten and graphite powders were mixed with commercial coarse grained WC-Co powder and then sintered. The microstructure of produced materials was free of defects and consisted of evenly distributed coarse and fine tungsten carbide grains in cobalt binder. The microstructure, hardness and fracture toughness of reactive sintered bimodal WC-Co hardmetals is exhibited. Developed bimodal hardmetal has perspective for demanding wear applications for its increased combined hardness and toughness. Compared to coarse material there is only slight decrease in fracture toughness (K1c is 14.7 for coarse grained and 14.4 for bimodal, hardness is increased from 1290 to 1350 HV units.DOI: http://dx.doi.org/10.5755/j01.ms.21.3.7511

  6. PREFACE: EDS2010 Preface

    Science.gov (United States)

    Heggie, Malcolm I.

    2011-03-01

    The biennial international conference on Extended Defects in Semiconductors started in 1978 with a meeting in Hünfeld, Germany. Subsequent meetings rotated between Poland, France, Great Britain, Germany, Russia and Italy, culminating in EDS2004 in Chernogolovka, EDS2006 in Halle and EDS2008 in Poitiers. EDS2010 was held at the University of Sussex at Brighton, UK from September 19th to 24th. An extension of the tabulation of this history, which first appeared on the EDS2006 website, is given in the attached PDF. It is with sadness that we note one of the founders of the series, Prof. Dr Helmut Alexander, passed away on 3 December 2009 and we were proud to dedicate EDS2010 to his memory. It has become a tradition to make an award in his name, and this year it was made to Ivan Isacov for his poster "Electrical levels of dislocation networks in p- and n-type silicon". A short and warm celebration of Prof. Dr Alexander's life by his friends and colleagues, Prof. Drs Helmut Gottschalk, Eicke Weber and Wolfgang Schröter, is included in this volume. The conference was a forum for the state-of-the-art of investigation and modelling of extended defects in semiconductors. Scientists from universities, research institutes and industry made contributions to a deeper understanding of extended defects, their interaction with point defects and their role in the development of semiconductor technology. The remit of the conference included extended defects, nanostructures, nanoparticles, quantum dots and interfaces within semiconducting materials ranging from narrow to wide band gaps, including graphene-derived materials and diamond. Scientific interests range from defect geometry, electronic structure, dynamics, spectroscopy, microscopy, reactions and chemistry to introduction mechanisms, such as implantation and strained layers and the operation of devices such as integrated circuits, heterostructures, and solar cells. The organisers were confronted with a long period between

  7. An ethical analysis of double bind conflicts as experienced by care workers feeding severely demented patients.

    Science.gov (United States)

    Akerlund, B M; Norberg, A

    1985-01-01

    When patients with incurable dementia diseases no longer take food or fluid voluntarily, the care workers experience distress and anxiety. Thirty-nine care workers were interviewed about their thoughts, feelings and attitudes towards feeding severely demented patients. A phenomenological approach was used and the interviews were developed, attention paid to Bateson's double bind theory, Kohlberg's theory of moral development and ethical theories. Ethical theories, principles and rules, containing messages at different logical levels and the lack of empirical knowledge of the demented patients' inner world, led to the care worker's difficult double bind situations. To solve the conflicts the care workers need insight in all aspects of the problem. In order to understand all the components in a double bind situation it is important to redefine it from outside.

  8. Correlation of thiamine metabolite levels with cognitive function in the non-demented elderly.

    Science.gov (United States)

    Lu, Jingwen; Pan, Xiaoli; Fei, Guoqiang; Wang, Changpeng; Zhao, Lei; Sang, Shaoming; Liu, Huimin; Liu, Meng; Wang, Hui; Wang, Zhiliang; Zhong, Chunjiu

    2015-12-01

    Thiamine metabolism is critical for glucose metabolism and also vital for brain function, which is susceptible to decline in the elderly. This study aimed to investigate whether thiamine metabolites correlate with cognitive function in the non-demented elderly and their impact factors. Volunteers >60 years old were recruited and their blood thiamine metabolites and Mini-Mental State Examination (MMSE) scores were measured. The apolipoprotein E (APOE) genotype, routine blood parameters, liver and kidney function, and levels of fasting blood glucose and triglycerides were also measured. The results showed that the thiamine diphosphate (TDP) level weakly correlated with MMSE score in the non-demented elderly. Participants with high TDP levels performed better in Recall and Attention and Calculation than those with low TDP. TDP levels were associated with the APOE ε2 allele, body mass index, hemoglobin level, fasting blood glucose, and triglycerides. Our results suggest that TDP, which is easily affected by many factors, impacts cognitive function in the elderly.

  9. Validačná terapia (Validation therapy. Nonpharmacological approach to dementic patient

    Directory of Open Access Journals (Sweden)

    Peter Tavel

    2009-06-01

    Full Text Available There is behaviour change occuring to old people, most of all dementic ones. Validation method by N. Feil helps to communicate with those people. The method is respecting uniqueness and originality of every person and is focused on diagnostics and development his or her abilities (let us say slow-down increasing the disease, all of that in different stages of dementia. It is based on a fact that by old people is very important the past, empathic listening, resolving the problems of the past and an effort to do important decisions before death. The old man withdraws if there is no acceptation and empathy that he or she is awaiting. Validation offers specific therapeutical technics and procedures by communication with old and dementic people.

  10. Gray and White Matter Contributions to Cognitive Frontostriatal Deficits in Non-Demented Parkinson's Disease

    OpenAIRE

    Price, Catherine C.; Jared Tanner; Nguyen, Peter T.; Nadine A Schwab; Sandra Mitchell; Elizabeth Slonena; Babette Brumback; Okun, Michael S; Mareci, Thomas H.; Dawn Bowers

    2016-01-01

    Objective This prospective investigation examined: 1) processing speed and working memory relative to other cognitive domains in non-demented medically managed idiopathic Parkinson’s disease, and 2) the predictive role of cortical/subcortical gray thickness/volume and white matter fractional anisotropy on processing speed and working memory. Methods Participants completed a neuropsychological protocol, Unified Parkinson’s Disease Rating Scale, brain MRI, and fasting blood draw to rule out vas...

  11. Comparison between visual assessment of MTA and hippocampal volumes in an elderly, non-demented population

    Energy Technology Data Exchange (ETDEWEB)

    Cavallin, Lena; Axelsson, Rimma [CLINTEC, Div. of Medical Imaging and Technology, Karolinska Inst., Karolinska Univ. Hospital, Stockholm (Sweden); Dept. of Radiology, Karolinska Univ. Hospital, Stockholm (Sweden)], e-mail: lena.cavallin@karolinska.se; Bronge, Lena [CLINTEC, Div. of Medical Imaging and Technology, Karolinska Inst., Karolinska Univ. Hospital, Stockholm (Sweden); Aleris Diagnostics, Stockholm (Sweden); Zhang, Yi [NVS, Novum, Karolinska Inst., Karolinska Univ. Hospital, Stockholm (Sweden); Oeksengaard, Anne-Rita [NVS, Novum, Karolinska Inst., Karolinska Univ. Hospital, Stockholm (Sweden); Ulleval Univ. Hospital and Asker and Baerum Hospital, Oslo (Norway); Wahlund, Lars-Olof [NVS, Novum, Karolinska Inst., Karolinska Univ. Hospital, Stockholm (Sweden); Swedish Brain Power, Karolinska Univ. Hospital, Stockholm (Sweden); Fratiglioni, Laura [ARC Karolinska Inst. Stockholm (Sweden)

    2012-06-15

    Background: It is important to have a replicable easy method for monitoring atrophy progression in Alzheimer's disease. Volumetric methods for calculating hippocampal volume are time-consuming and commonly used in research. Visual assessments of medial temporal lobe atrophy (vaMTA) is a rapid method for clinical use. This method has not been tested in a large non-demented population in comparison with volumetry measurements. Since hippocampal volume decreases with time even in normal aging there is also a need to study the normal age differences of medial temporal lobe atrophy. Purpose: To compare visual assessment of medial temporal lobe atrophy (vaMTA) with hippocampal volume in a healthy, non-demented elderly population. To describe normal ageing using vaMTA. Material and Methods: Non-demented individuals aged 60, 66, 72, 78, 81, 84, and {>=}87 years old were recruited from the Swedish National study on Ageing and Care in Kungsholmen (SNAC-K), Sweden. Standard magnetic resonance imaging (MRI) scans, vaMTA, and calculations of hippocampal volumes were performed in 544 subjects. Results: Significant correlation (rs = -0.32, P < 0.001, sin; and rs = -0.26, P < 0.001, dx) was found between hippocampal volume measurements and vaMTA. In normal ageing, almost 95% of {<=}66-year-olds had a medial temporal lobe atrophy (MTA) score {<=}1, with possible scores ranging from 0 to 4. Subjects aged 72, 78, and 81 years scored {<=}2, while the two oldest age groups had scores {<=}3. Conclusion: There was a highly significant correlation between volumetric measurements of the hippocampus and MTA scoring. In normal ageing, there is increasing MTA score. For non-demented elderly individuals {<=}70 years, an MTA score of 0-1 may be considered normal, compared with MTA {<=}2 for 70-80-years and MTA 3 for >80-year-old individuals.

  12. Greater memory impairment in dementing females than males relative to sex-matched healthy controls.

    Science.gov (United States)

    Gale, Shawn D; Baxter, Leslie; Thompson, Juliann

    2016-01-01

    Previously we demonstrated sex differences in episodic memory in healthy elderly and suggested that normative data be separated by sex. The present study extended the exploration of sex differences on memory measures into two clinical populations, mild cognitive impairment (MCI) and Alzheimer's disease (AD). Seventy-six subjects with MCI and 101 subjects with AD diagnosed by a multidisciplinary team were included. These two groups were also compared to a group of 177 healthy elderly control participants. Sex differences on the Rey Auditory Verbal Learning Test (RAVLT; total and delayed recall) raw scores and Brief Visuospatial Memory Test-Revised (BVMT-R) were demonstrated within the healthy but not the MCI or AD groups. Calculating z scores by sex for both dementing groups based on the healthy controls suggested a larger performance gap between healthy and dementing women than between healthy and dementing men. MCI females were on average 0.48 standard deviations lower for total verbal learning compared to healthy female controls than were MCI males when compared to healthy male controls. For verbal delayed recall the gap was even larger (SD = 1.09). Similarly, on the BVMT-R, a measure of visual memory, the difference was 0.60 standard deviations for total visual learning and 0.99 standard deviations for delayed recall. This same sex difference, with females showing greater impairment compared to the controls group than did the males, was also present within the AD group. The greater memory impairment in dementing females rather than males when compared to sex-matched healthy controls was unlikely to be due to more severe illness since females performed equivalently to males on the Clinical Dementia Rating Scale, Mini-Mental Status Examination, and Dementia Rating Scale, and were also similar for age, education, and apolipoprotein status. The present study suggested relatively greater memory impairment in females with MCI or AD than in controls.

  13. Multiple intracranial hemorrhages in a normotensive demented patient: A probable cerebral amyloid angiopathy.

    Science.gov (United States)

    Chitsaz, Ahmad; Norouzi, Rasul; Marashi, Seyed Mohammad Javad; Salimianfard, Marzieh; Fard, Salman Abbasi

    2012-01-01

    Cerebral amyloid angiopathy (CAA) is the most common cause of lobar intracerebral hemorrhage. Repeated bleeding may be presented with vascular dementia. We have reported a 68-year-old normotensive demented patient with probable CAA presented with hemiparesia, headache and vomiting. According to the experience of this case, it is recommended to consider CAA for normotensive elderly patients presented with multiple and superficial intracerebral hemorrhage.

  14. Ed Deutschman Interview [video

    OpenAIRE

    Deutschman, Ed

    2011-01-01

    Background: Ed Deutschman was a Navy cadet at the Del Monte Pre-Flight School, located at the now (2013) Naval Postgraduate School. Mr Deutschman visited the Dudley Knox Library on May 2, 2011, and spoke about his service in World War II as a Corsair fighter pilot in the Pacific.

  15. Crystalline silicates in planetary nebulae with [WC] central stars

    NARCIS (Netherlands)

    Waters, LBFM; Beintema, DA; Zijlstra, AA; de Koter, A; Molster, FJ; Bouwman, J; de Jong, T; Pottasch, [No Value; de Graauw, T

    We present ISO-SWS spectroscopy of the cool dusty envelopes surrounding two Planetary Nebulae with [WC] central stars, BD+30 3639 and He 2-113. The lambda <15 mu m region is dominated by a rising continuum with prominent emission from C-rich dust (PAHs), while the long wavelength part shows narrow

  16. Characteristics of Planetary Nebulae with [WC] Central Stars

    Directory of Open Access Journals (Sweden)

    M. Peña

    2003-01-01

    Full Text Available Utilizando datos espectro-fotométricos de alta resolución, hemos analizado las condiciones físicas, las abundancias químicas y la cinemática de una muestra amplia de nebulosas planetarias con estrella central de tipo [WC]. Los resultados se comparan con las características de nebulosas planetarias ionizadas por estrellas con líneas de emisión débiles (WELS o estrellas centrales no-WR. Encontramos que las WRPNe muestran una proporción mayor de nebulosas ricas en nitrógeno. Ninguna de las 9 nebulosas alrededor de WELS analizadas muestran enriquecimiento de nitrógeno. Las WRPNe presentan mayores velocidades de expansión y mayor turbulencia, lo que indica que la energía mecánica del viento estelar masivo ha afectado de manera importante el comportamiento cinemático de la nebulosa. También hemos encontrado que las PNe con estrellas de alta temperatura (por lo tanto mas evolucionadas se expanden mas rápido. El efecto es mas importante en WRPNe. Esto podría utilizarse para comprobar la secuencia evolutiva, [WC]-tardías→ [WC]-tempranas, que se ha propuesto para estrellas [WC].

  17. Characteristics of Nanophase WC and WC-3 wt% (Ni, Co, and Fe Alloys Using a Rapid Sintering Process for the Application of Friction Stir Processing Tools

    Directory of Open Access Journals (Sweden)

    Daeup Kim

    2015-01-01

    Full Text Available Microstructures and mechanical characteristics of tungsten carbide- (WC- based alloys, that is, WC, WC-3 wt% Ni, WC-3 wt% Co, and WC-3 wt% Fe, fabricated using a spark plasma sintering (SPS method for the application of friction stir processing tools were evaluated. The sintered bodies with a diameter of 66 mm showed relative densities of up to 99% with an average particle size of 0.26~0.41 μm under a pressure condition of 60 MPa with an electric current for 35 min without noticeable grain growth during sintering. Even though no phase changes were observed after the ball milling process the phases of W2C and WC1-x appeared in all sintered samples after sintering. The Vickers hardness and fracture toughness of the WC, WC-3 wt% Ni, WC-3 wt% Co, and WC-3 wt% Fe samples ranged from 2,240 kg mm2 to 2,730 kg mm2 and from 6.3 MPa·m1/2 to 9.1 MPa·m1/2, respectively.

  18. Investigation of WC-Co Electrospark Coatings with Various Carbon Contents

    Science.gov (United States)

    Burkov, A. A.; Pyachin, S. A.

    2014-06-01

    Electrospark deposition was employed to clad WC-10%Co, W/C1.6 -10%Co, and W/C0.5 -10%Co hard alloys on steel 1035, and the tribological properties of the coatings obtained were examined. The influence of the W/C ratio in the electrode materials on the decarburization of tungsten carbide was studied. It is shown that the degree of tungsten carbide degradation can be reduced by increasing the concentration of carbon in the WC-Co electrode materials, and also that the WC decarburization reaction is reversible on annealing. Coatings deposited using new electrode materials with an excess of carbon (W/C0.5) and/or tungsten (W/C1.6) have increased microhardness and improved frictional characteristics compared with the conventional coating.

  19. Effect of WC/Co coherency phase boundaries on Fracture toughness of the nanocrystalline cemented carbides.

    Science.gov (United States)

    Xie, Hongxian; Song, Xiaoyan; Yin, Fuxing; Zhang, Yongguang

    2016-08-03

    The effect of coherency WC/Co phase boundaries on the fracture toughness of the nanocrystalline WC-Co cemented carbides is studied by MD simulation method. The simulation results show that the nanocrystalline WC-Co cemented carbides with coherency WC/Co phase boundaries has higher fracture toughness than that without coherency WC/Co phase boundaries. Moreover, the mechanism of why coherency WC/Co phase boundaries can improve the fracture toughness of the nanocrystalline cemented carbides is also investigated. It is found the fact that the separation energy of the coherent WC/Co phase boundary is larger than that of the incoherent WC/Co phase boundaries is the main reason for this excellent mechanical property.

  20. Influence of energetic ion bombardment on W-C : H coatings deposited with W and WC targets

    NARCIS (Netherlands)

    Strondl, C; Carvalho, NM; De Hosson, JTM; Krug, TG

    2005-01-01

    Tungsten containing diamond-like carbon (W-C:H) coatings have been produced by unbalanced magnetron sputtering using two different target materials. In the first series of coatings, W has been used as target material, and in the second series, WC has been used as target material. In both series of W

  1. A study on the synthesis and microstructure of WC-TiN superlattice coating

    Energy Technology Data Exchange (ETDEWEB)

    Yoon, J.S.; Myung, H.S.; Han, J.G. [Sung Kyun Kwan Univ., Suwon (Korea). Plasma Appl. Mater. Lab.; Musil, J. [Dept. of Physics, Univ. of West Bohemia (Czech Republic)

    2000-09-01

    WC-TiN superhard coatings are formulated to form a nanoscaled superlattice by separate arc reactive evaporation of Ti and WC. The microstructure of WC-TiN films was identified to be a superlattice of TiN and {beta}-WC{sub 1-x} phases with modulation period ({lambda}) of 5-13 nm and the lattice planes were continuous through the TiN and {beta}-WC{sub 1-x} layers. The residual stress of WC-TiN films was measured to be 7.9 GPa. This high stress was reduced to 2.2 GPa by introducing Ti or Ti-WC interlayers. Ti-WC interlayer also increased the film adhesion strength. In spite of almost the same residual stress of 2.2-2.3 GPa, Ti-WC/WC-TiN film showed a higher adhesion strength of 48.5 N than that of Ti/WC-TiN film. These results are attributed to the low residual stress and higher stiffness of the Ti-WC interlayer than the soft Ti interlayer. The microhardness of Ti-WC/WC-TiN film on cemented carbide was measured to be 40 GPa and the maximum hardness was obtained as the period ({lambda}) was approximately 7 nm. This value is approximately 1.5 times higher than that of the TiN single layer film. Other WC-TiN superlattice coatings with Ti and WC interlayers showed a hardness range of 38-40 GPa. The ratio H{sup 3}/E{sup 2} (plastic deformation resistance) of WC-TiN superlattice films with various interlayers was calculated to be in a range from 0.18 to 0.33. This paper reports the preparation of WC-TiN superlattice coatings on WC-Co and Si substrates using a multi-cathode arc ion-plating system. The microstructures and mechanical properties of WC-TiN superlattice films were investigated, too. (orig.)

  2. Physicians' experiences with demented patients with advance euthanasia directives in the Netherlands.

    Science.gov (United States)

    Rurup, Mette L; Onwuteaka-Philipsen, Bregje D; van der Heide, Agnes; van der Wal, Gerrit; van der Maas, Paul J

    2005-07-01

    To estimate the incidence of (compliance with) advance euthanasia directives of patients suffering from dementia in the Netherlands and to gain knowledge about the experiences of physicians. Retrospective interview study. Physicians in the Netherlands. Four hundred ten physicians. Physicians were interviewed about their demented patients who had an advance euthanasia directive. Nursing home physicians were interviewed more extensively. Approximately 2,200 demented patients with an advance euthanasia directive die annually after being treated by a physician who knows about this directive. In 76% of such cases, compliance with the directive was discussed, but euthanasia was seldom performed. In two-thirds of the cases of demented nursing home patients with an advance euthanasia directive, the physician was able to identify during the course of the disease a situation for which the patient had intended the directive. One-quarter of the nursing home physicians thought that their most recent patient suffered unbearably to a (very) high degree, and half of them thought that the patient suffered hopelessly to a (very) high degree. In three-quarters of the cases, the relatives did not want the nursing home physician to comply with the directive, but they did want to respect the patient's wishes by forgoing life-prolonging treatment, which occurred in approximately 90% of cases. Most nursing home physicians think that the suffering of patients with dementia can be unbearable and hopeless as a consequence of dementia, but most physicians do not consider dementia to be grounds for euthanasia, unless perhaps the patient has an additional illness.

  3. Neuropsychological Subgroups in Non-Demented Parkinson's Disease: A Latent Class Analysis.

    Science.gov (United States)

    Brennan, Laura; Devlin, Kathryn M; Xie, Sharon X; Mechanic-Hamilton, Dawn; Tran, Baochan; Hurtig, Howard H; Chen-Plotkin, Alice; Chahine, Lama M; Morley, James F; Duda, John E; Roalf, David R; Dahodwala, Nabila; Rick, Jacqueline; Trojanowski, John Q; Moberg, Paul J; Weintraub, Daniel

    2017-01-01

    Methods to detect early cognitive decline and account for heterogeneity of deficits in Parkinson's disease (PD) are needed. Quantitative methods such as latent class analysis (LCA) offer an objective approach to delineate discrete phenotypes of impairment. To identify discrete neurocognitive phenotypes in PD patients without dementia. LCA was applied to a battery of 8 neuropsychological measures to identify cognitive subtypes in a cohort of 199 non-demented PD patients. Two measures were analyzed from each of four domains: executive functioning, memory, visuospatial abilities, and language. Additional analyses compared groups on clinical characteristics and cognitive diagnosis. LCA identified 3 distinct groups of PD patients: an intact cognition group (54.8%), an amnestic group (32.2%), and a mixed impairment group with dysexecutive, visuospatial and lexical retrieval deficits (13.1%). The two impairment groups had significantly lower instrumental activities of daily living ratings and greater motor symptoms than the intact group. Of those diagnosed as cognitively normal according to MDS criteria, LCA classified 23.2% patients as amnestic and 9.9% as mixed cognitive impairment. Non-demented PD patients exhibit distinct neuropsychological profiles. One-third of patients with LCA-determined impairment were diagnosed as cognitively intact by expert consensus, indicating that classification using a statistical algorithm may improve detection of initial and subtle cognitive decline. This study also demonstrates that memory impairment is common in non-demented PD even when cognitive impairment is not clinically apparent. This study has implications for predicting eventual emergence of significant cognitive decline, and treatment trials for cognitive dysfunction in PD.

  4. Thermal properties of WC-10 wt. (% Co alloys

    Directory of Open Access Journals (Sweden)

    Francisco de Assis Léo Machado

    2008-03-01

    Full Text Available In this article, photothermal techniques were used in order to determine some thermal properties: diffusivity, conductivity, effusivity and specific heat capacity of WC-10 wt. (% Co six samples subjected to different sintering processes. The samples were sintered using high pressure - high temperature (HPHT sintering system. The open cell photoacoustic (OPC used to measure thermal diffusivity is described in detail. The values of thermal properties here measured and evaluated are consistent to those previously reported in the literature.

  5. FAINT EMISSION LINES IN PLANETARY NEBULAE WITH A [WC] NUCLEUS

    Directory of Open Access Journals (Sweden)

    J. García-Rojas

    2011-01-01

    Full Text Available Presentamos los primeros resultados del análisis de una muestra de 14 nebulosas planetarias con núcleo [WC] con líneas de recombinación débiles de oxígeno y carbono. Los resultados están basados en espectros profundos obtenidos con el espectrógrafo MIKE en el telescopio Magallanes-Clay de 6.5 m en Chile.

  6. [WC] Stellar wind turbulent outflows feeding the ism

    Directory of Open Access Journals (Sweden)

    Y. Grosdidier

    2002-01-01

    Full Text Available Se han detectado uctuaciones en los vientos de las estrellas centrales, con tipos [WC 8{9], de nebulosas planetarias. Estructuras en movimiento de las l neas C III 5696 y C IV 5801/12 son interpretadas como inhomogeneidades aceleradas por los vientos Wolf-Rayet. Sus par ametros cinem aticos son comparados con los observados en estrellas Wolf-Rayet masivas.

  7. Abundances and ADFs in PNe with WC central stars

    CERN Document Server

    García-Rojas, Jorge; Morisset, Christophe; Ruiz, Maria Teresa

    2011-01-01

    We present preliminary results obtained from the analysis of very deep echelle spectra of a dozen planetary nebulae with [WC] or weak emission lines (wels) central stars. The computed abundance discrepancy factors (ADFs) are moderate, with values lower than 4. In principle, no evidence of the H-poor metal enriched inclusions proposed by Liu et al. (2000) have been found. However, a detailed analysis of the data is in progress.

  8. Morpho-Structural Characterization of WC20Co Deposited Layers

    Science.gov (United States)

    Tugui, C. A.; Vizureanu, P.

    2017-06-01

    Hydroelectric power plants use the power of water to produce electricity. In this paper we propose a solution that will increase the efficiency of turbine operation by implementing new innovative technologies to increase the working characteristics by depositing hard thin films of tungsten carbide. For this purpose hard tough deposits with WC20Co and Jet Plasma Jet on X3CrNiMo13-4 stainless steel were used for the realization of the Francis turbine with vertical shaft.

  9. High temperature wear performance of HVOF-sprayed Cr3C2-WC-NiCoCrMo and Cr3C2-NiCr hardmetal coatings

    Science.gov (United States)

    Zhou, Wuxi; Zhou, Kesong; Li, Yuxi; Deng, Chunming; Zeng, Keli

    2017-09-01

    A novel Cr3C2-WC-NiCoCrMo and commercial Cr3C2-NiCr thermal spray-grade powders with particle size of -45 + 15 μm were prepared by an agglomeration and sintering process. Cr3C2-WC-NiCoCrMo and Cr3C2-NiCr coatings were deposited by high velocity oxygen fuel (HVOF) spraying. The fundamental properties of both coatings were evaluated and friction wear test against Al2O3 counterbodies of both coatings at high temperatures (450 °C, 550 °C, 650 °C) were carried out ball-on-disk high temperature tribometer. All specimens were characterized by optical microscopy, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy with energy dispersive spectroscopy (SEM/EDS) and 3D non-contact surface mapping profiler. The results have shown that the Cr3C2-WC-NiCoCrMo coating exhibited lower porosity, higher micro-hardness compared to the Cr3C2-NiCr coating. The Cr3C2-WC-NiCoCrMo coating also exhibited better wear resistance and higher friction coefficient compared to the Cr3C2-NiCr coating when sliding against the Al2O3 counterpart. Wear rates of both coatings increased with raising temperature. Both coatings experienced abrasive wear; hard phase particles (WC and Cr3C2) with different sizes, distributed in the matrix phase, will effectively improve the resistance against wear at high temperatures.

  10. A Novel Method for Direct Synthesis of WC-Co Nanocomposite Powder

    Science.gov (United States)

    Zhu, M.; Bao, X. Y.; Yang, X. P.; Gu, N. S.; Wang, H.; Zeng, M. Q.; Dai, L. Y.

    2011-09-01

    In this study, a novel method, termed dielectric-barrier-discharge-plasma (DBDP) assisted ball milling and low-temperature carburization, was used to synthesize WC-Co nanocomposite powder. X-ray diffraction, scanning/transmission electron microscopy, and differential scanning calorimetry were used to characterize the microstructure of powders. Starting from W, Co, and graphite powder mixtures, the DBDP-milled W-C-10Co powder exhibited a flakelike morphology with very fine lamellar structure. The WC-Co composite powder was synthesized at 1273 K (1000 °C), which is much lower than the requisite temperature for the conventional carburizing method. The obtained WC-Co composite powder had a nanocomposite microstructure in which fine WC particles were bounded by homogenously distributed Co phase, and the WC crystals had a slablike morphology with a planar size of about 200 nm and carburization temperature and the nanocomposite structure of WC-Co powder.

  11. Synthesis of Nanocrystalline WC Single-Phase Refractory via Mechanical Milling

    Directory of Open Access Journals (Sweden)

    Mansour Razavi

    2011-01-01

    Full Text Available In this paper the possibility of production of nanocrystalline WC single-phase by mechanical milling has been investigated. The raw materials containing tungsten and carbon with WC as nucleation were milled in a planetary ball mill and sampled in different times. Studies showed that after 75 hours of milling the WC with W2C was produced and remained constant in higher milling time. Adding WC to raw materials at the beginning process leads to the fact that after 50 hours of milling only WC was synthesized without undesirable W2C phase. This material remained stable until higher times of milling too. From broadening of XRD peaks, the crystalline size in synthesized WC was estimated in nanometer scale which lower than the system containing primary WC, and it means that the strain in this system was lower than first system.

  12. Diode laser cladding of Co-based composite coatings reinforced by spherical WC particles

    Science.gov (United States)

    Janicki, Damian; Górka, Jacek; Czupryński, Artur; Kwaśny, Waldemar; Żuk, Marcin

    2016-12-01

    A laser cladding system consisting of a direct diode laser with the flat-top beam profile and an off-axis powder injection nozzle has been used to fabricate Co-based (Satellite 6) metal matrix composite coatings reinforced by spherical-shaped WC particles. Non-porous coatings with the WC fraction of about 50 vol.% and a low dissolution of the WC particles in the matrix have been obtained. The heat input level affects the degree of WC dissolution and the matrix mean free path between the embedded WC particles. Comparative erosion tests between the metallic Satellite 6 and composite Satellite 6/WC coatings showed that the composite coatings exhibit a superior erosion resistance only at the oblique impingement condition. Generally, a low erosion resistance of the composite coatings at the normal impingement is mainly attributed to a very smooth interface between the spherical-shaped WC particles and the matrix alloy.

  13. A pilot usability study of MINWii, a music therapy game for demented patients.

    Science.gov (United States)

    Boulay, Mélodie; Benveniste, Samuel; Boespflug, Sandra; Jouvelot, Pierre; Rigaud, Anne-Sophie

    2011-01-01

    MINWii is a music therapy game for the renarcissization of demented patients. It lets players improvise or play songs of their choice by pointing at a virtual keyboard with a Wiimote Pistol. We present the results of a three-month usability study we conducted with 7 institutionalized patients suffering from mild to moderately severe Alzheimer's disease at the LUSAGE Living Lab in Paris. We demonstrate that MINWii is indeed usable by AD patients despite their motor and cognitive impairments: our results, which were largely computed automatically thanks to MINWii's extensive logging capabilities, show either an instant mastery or a clear learning effect depending on patients' cognitive abilities. Moreover, patients were overall very satisfied with the game and expressed a desire to repeat the experience: MINWii fosters positive interaction with the caregivers and elicits powerful reminiscence with even the most severely impaired patients. This study justifies future research to assess the lasting effects of playing MINWii on both quality of life and cognitive impairment in demented patients.

  14. [Demented patients' rights in institutions--the relatives' point of view].

    Science.gov (United States)

    Teeri, S; Välimäki, M; Katajisto, J

    1998-01-01

    The aim of this study was to describe the views of demented patients' relatives concerning the fulfillment of patients' rights in institutions. The Act on Patients' Rights and Status of March 1st, 1993, served as the basis for this study. Of the Act, the patients' rights to good care and treatment, to information and to self-determination were discussed. The data were collected from six medical wards for long-term patients at a hospital and from an old people's home by using a questionnaire. Ninety relatives of demented patients participated in the study, the response rate being 60%. The data were analyzed statistically. The relatives stated that the right to good care and treatment was realized best. The right to information was fulfilled quite well according to the respondents. The fact that the staff would not give information on their own initiative was regarded as lack of information. The right to self-determination was realized most poorly; 44% of the respondents could not say whether their relatives were able to affect the care with their opinions and wishes, and 59% could not answer whether the patient could reject the care. On the contrary, the respondents preferred their own right to influence decision-making concerning the care. Pensioners who answered the inquiry were more satisfied with the fulfillment of the patients' rights than others when the three rights were discussed. However, children as relatives were more dissatisfied than other relatives with the fulfillment of the right to information and self-determination.

  15. Effect of Composition on Mechanical Properties of Mullite-WC Nano Composites Prepared by Spark Plasma Sintering

    Directory of Open Access Journals (Sweden)

    H. Rajaei

    2016-12-01

    Full Text Available Mullite-WC composites were prepared from Mullite and WC powders by spark plasma sintering at 1400 °C for a holding time of 180 s under 30 MPa. Microstructure, strength, and hardness of the mullite-WC composites were studied. The mullite-WC composite containing 5-20 wt% WC reached over 94 % theoretical density. The strength and Vickers hardness of mullite-(10 wt% WC sintered composite reached maximum values of 298 MPa, and 1589 HV, respectively demonstrating that the introduction of WC significantly enhances the mechanical properties of the mullite matrix.

  16. The role of the binder phase in the WC-Co sintering

    Directory of Open Access Journals (Sweden)

    Silva A.G.P. da

    2001-01-01

    Full Text Available The sintering of hardmetal in the solid state is studied. The influence of the WC particle size on the sintering kinetics, the role of the binder phase in the densification process and how sintering depends on the heating conditions are investigated. It is observed that alloys with different WC particle size show quite different structural evolution during sintering, although the densification mechanisms are the same. This is explained by the formation of agglomerates of WC and Co. Hardmetal alloys can sinter very rapidly when high heating rates are used, since rapid heating accelerates the binder spreading and the formation of WC-Co agglomerates. The binder phase (Co spreads on the WC particles initially as a thin layer. Subsequently, more Co spreads on this layer and WC-Co agglomerates are formed.

  17. Effects of WC particle size on the wear resistance of laser surface alloyed medium carbon steel

    Science.gov (United States)

    Tong, Xin; Li, Fu-hai; Kuang, Min; Ma, Wen-you; Chen, Xing-chi; Liu, Min

    2012-01-01

    The CO2 laser surface alloying technique was used to form wear resistance layers on medium carbon steel with a kind of spherical WC powder. The effects of WC particle size on the abrasive wear resistance were thoroughly investigated. The results indicate that the laser alloyed layer is characterized by dendritic primary phase and ledeburite microstructure, consisting of austenite, martensite and carbides of Fe3W3C, W2C and WC. The laser surface alloying with WC powder could improve the abrasive wear resistance of the medium carbon steel by over 63%. The factors such as the hardness, the amount and the distribution of WC particle determined the laser alloyed samples' wear resistance, and the laser alloyed sample with WC powder of 88-100 μm diameter presented the best wear resistance in this study. Furthermore, the wear resistance mechanisms of the laser alloyed layers were also explored.

  18. Synthesis of Al2O3/WC powder by aluminothermic reduction and carbonization method

    Institute of Scientific and Technical Information of China (English)

    韩兵强; 李楠

    2004-01-01

    Al2O3/WC powder was synthesized by means of aluminothermic reduction-carbonization with metallic Al powder, yellow tungsten oxide and carbon black or graphite as raw materials under the protection of coke granules.The effects of Al2O3 content, temperature, C/WO3 molar ratio, and atmosphere on the synthesis of Al2O3/WC powder were studied. The results show that the relative content of WC and W2C is strongly influenced by the factors mentioned-above. Carbon black has higher reactivity than graphite. Al2O3-WC composite is easier to obtain under the protection of coke granules than under argon atmosphere. The CO in the coke layer can easily react with tungsten to form WC and to transfer from W2 C to WC.

  19. Microstructure and mechanical properties of WC-Co reinforced with NbC

    Directory of Open Access Journals (Sweden)

    Acchar Wilson

    2004-01-01

    Full Text Available Cemented carbides such as tungsten carbide-cobalt WC-Co composites have been widely used as cutting tool materials. Several reports have shown the influence of different factors such as grain size, type and amount of binder phase and the addition of hard particles on the properties of WC-Co. The purpose of this work was to investigate the effect of niobium carbide on the microstructure and mechanical properties of WC-Co. Specimens of WC-Co reinforced with NbC were mixed and subsequently hot-pressed in a inert atmosphere. The WC-Co-NbC composite material exhibited high hardness values (18.9 GPa, flexural strength (2100 MPa and fracture toughness (11.2 MPa.m½ . TEM analysis has shown a bimodal grain size distribution of WC.

  20. Changes in gait while backward counting in demented older adults with frontal lobe dysfunction.

    Science.gov (United States)

    Allali, Gilles; Kressig, Reto W; Assal, Frédéric; Herrmann, François R; Dubost, Véronique; Beauchet, Olivier

    2007-10-01

    Gait disorders caused by dementia have been associated with frontal lobe dysfunction. Dual-tasking is used to explore the involvement of cortical level in gait control. It has been shown that dual-task induced gait changes that could be related to (1) the efficiency of executive function, (2) the level of difficulty involved in the walking-associated task, or (3) the articulo-motor components comprised in the walking-associated task. A better understanding of dual-task related changes in demented subjects with frontal lobe dysfunction could help us to clarify the role of the frontal lobe in motor gait control. To assess and compare the effects of two mental arithmetic tasks involving similar articulo-motor components but different level of difficulty on the mean values and coefficient of variation (CV) of stride time among demented older adults with impaired executive function. The mean values and coefficients of variation of stride time were measured using a GAITRite-System among 16 demented older adults with impaired executive function while walking with and without forward counting (FC) and backward counting (BC). The mean values and CV of stride time were significantly higher under both dual-task conditions than during a simple walking task (p<0.05). The change in CV of stride time during BC was significantly higher when compared with the change during FC (p=0.015), whereas the change in mean value was not significant (p=0.056). There was no difference between the dual-task and single task condition as far the number of enumerated figures were concerned (p=0.678 for FC and p=0.069 for BC), but significantly fewer figures were enumerated while BC compared with FC (p<0.001). BC provoked more changes in gait parameters than FC with major modification in gait variability related to an inappropriate focusing of attention. These findings suggest that the CV may be a suitable criterion for the assessment of gait control.

  1. Investigation on cored-eutectic structure in Ni60/WC composite coatings fabricated by wide-band laser cladding

    Energy Technology Data Exchange (ETDEWEB)

    Ma, Qunshuang, E-mail: maqunshuang@126.com; Li, Yajiang, E-mail: yajli@sdu.edu.cn; Wang, Juan, E-mail: jwang@sdu.edu.cn; Liu, Kun, E-mail: liu_kun@163.com

    2015-10-05

    Highlights: • Perfect composite coatings were fabricated using wide-band laser cladding. • Special cored-eutectic structure was synthesized in Ni60/WC composite coatings. • Cored-eutectic consists of hard carbide compounds and fine lamellar eutectic of M{sub 23}C{sub 6} carbides and γ-Ni(Fe). • Wear resistance of coating layer was significantly improved due to precipitation of M{sub 23}C{sub 6} carbides. - Abstract: Ni60 composite coatings reinforced with WC particles were fabricated on the surface of Q550 steel using LDF4000-100 fiber laser device. The wide-band laser and circular beam laser used in laser cladding were obtained by optical lens. Microstructure, elemental distribution, phase constitution and wear properties of different composite coatings were investigated. The results showed that WC particles were partly dissolved under the effect of wide-band fiber laser irradiation. A special cored-eutectic structure was synthesized due to dissolution of WC particles. According to EDS and XRD results, the inside cores were confirmed as carbides of M{sub 23}C{sub 6} enriched in Cr, W and Fe. These complex carbides were primarily separated out in the molten metal when solidification started. Eutectic structure composed of M{sub 23}C{sub 6} carbides and γ-Ni(Fe) grew around carbides when cooling. Element content of Cr and W is lower at the bottom of cladding layer. In consequence, the eutectic structure formed in this region did not have inside carbides. The coatings made by circular laser beam were composed of dendritic matrix and interdendritic eutectic carbides, lacking of block carbides. Compared to coatings made by circular laser spot, the cored-eutectic structure formed in wide-band coatings had advantages of well-distribution and tight binding with matrix. The uniform power density and energy distribution and the weak liquid convection in molten pool lead to the unique microstructure evolution in composite coatings made by wide-band laser

  2. A[Beta] Deposits in Older Non-Demented Individuals with Cognitive Decline Are Indicative of Preclinical Alzheimer's Disease

    Science.gov (United States)

    Villemagne, V. L.; Pike, K. E.; Darby, D.; Maruff, P.; Savage, G.; Ng, S.; Ackermann, U.; Cowie, T. F.; Currie, J.; Chan, S. G.; Jones, G.; Tochon-Danguy, H.; O'Keefe, G.; Masters, C. L.; Rowe, C. C.

    2008-01-01

    Approximately 30% of healthy persons aged over 75 years show A[beta] deposition at autopsy. It is postulated that this represents preclinical Alzheimer's disease (AD). We evaluated the relationship between A[beta] burden as assessed by PiB PET and cognitive decline in a well-characterized, non-demented, elderly cohort. PiB PET studies and…

  3. Drowsiness

    Science.gov (United States)

    ... In: Kryger MH, Roth T, Dement WC, eds. Principles and Practice of Sleep Medicine . 5th ed. Philadelphia, PA: Elsevier Saunders; 2011:chap 143. Review Date 8/29/2015 Updated by: Laura J. Martin, MD, MPH, ABIM Board Certified in Internal Medicine and Hospice and Palliative Medicine, Atlanta, GA. ...

  4. Synthesis of WC powder through microwave heating of WO3-C mixture

    Science.gov (United States)

    Behnami, Amir Karimzadeh; Hoseinpur, Arman; Sakaki, Masoud; Bafghi, Mohammad Sh.; Yanagisawa, Kazumichi

    2017-02-01

    A simple, easy, and low-cost process for the fabrication of tungsten carbide (WC) powder through microwave heating of WO3-C mixtures was developed. Thermodynamic calculations and experimental investigations were carried out for WO3-C and W-C systems, and a formation mechanism was proposed. In the results, for the synthesis of WC, the use of over stoichiometric amount of C together with a specially assembled experimental setup (which effectively retains heat in the system) is necessary. The WC powder is successfully obtained by heating WO3:5C mixture for 900 s in a domestic microwave oven.

  5. Effect of flame conditions on abrasive wear performance of HVOF sprayed nanostructured WC-12Co coatings

    Institute of Scientific and Technical Information of China (English)

    WANG Yu-yue; LI Chang-jiu; MA Jian; YANG Guan-jun

    2004-01-01

    Nanostructured WC-12Co coatings were deposited by high velocity oxy-fuel (HVOF) spraying with an agglomerated powder. The effect of flame conditions on the microstructure of the nanostructured coatings was investigated. The wear properties of the coatings were characterized using a dry rubber-wheel wear test. The results show that the nanostructured WC-Co coatings consist of WC, W2C, W and an amorphous binder phase. The microstructure of the coating is significantly influenced by the ratio of oxygen flow to fuel flow. Under the lower ratio of oxygen/fuel flow, the nanostructured coating presents a relative dense microstructure and severe decarburization of WC phase occurs during spraying. With increasing ratio of oxygen/fuel flow, the bonding of WC particles in the coating becomes loose resulting from the original structure of feedstock and the decarburization of WC becomes less owing to limited heating to the powder. Both the decarburization of WC particles in spraying and the bonding among WC particles in the coatings affect the wear performance. The examination of the worn surfaces of the nanostructured coatings reveals that the dominant wear mechanisms would be spalling from the interface of WCCo splats when spray particles undergo a limited melting. While the melting state of the spray particles is improved,the dominant wear mechanisms become the plastic deformation and plowing of the matrix and spalling of WC particles from the matrix.

  6. Comparative study of a [WC 6] nucleus with other emission-lines nuclei of planetary nebulae

    CERN Document Server

    Acker, A; Cuisinier, F

    1995-01-01

    The central star (CSPN) of the planetary nebula M 1-25 (PN G 4.9+4.9) is classified as a [WC 6] star, the only CSPN of this subclass known at this time. A comparison with the other emission-lines CSPN (the [WC]-class and the 'weak emission-lines stars' or {\\em wels}-class) shows that (1) the characteristics of this [WC 6] star fit well inside the main properties of the other [WC] CSPN ; (2) the [WC] CSPN seem to evolve from the [WC 8-11] (latter) to [WC 2-4] (earlier) subclasses, say from dense nebulae with cool stars to more extended nebulae with hot nuclei, as for other CSPN ; (3) on the two-colour IRAS diagram,the [WC] and the {\\em wels} CSPN form two different groups : the progenitors of the [WC]-type CSPN seem to be Carbon stars evolving along post-AGB tracks, whereas the {\\em wels} CSPN seem to be related to OH/IR stars, some of them having possibly experienced a late helium-flash.

  7. Functional connectivity density mapping of depressive symptoms and loneliness in non-demented elderly male

    Directory of Open Access Journals (Sweden)

    Chen-Chia eLan

    2016-01-01

    Full Text Available Background: Depression and loneliness are prevalent and highly correlated phenomena among the elderly and influence both physical and mental health. Brain functional connectivity changes associated with depressive symptoms and loneliness are not fully understood.Methods: A cross-sectional functional MRI study was conducted among 85 non-demented male elders. Geriatric depression scale-short form and loneliness scale were used to evaluate the severity of depressive symptoms and loneliness, respectively. Whole brain voxel-wise resting-state functional connectivity density (FCD mapping was performed to delineate short-range FCD (SFCD and long-range FCD (LFCD. Regional correlations between depressive symptoms or loneliness and SFCD or LFCD were examined using general linear model, with age incorporated as a covariate and depressive symptoms and loneliness as predictors.Results: Positive correlations between depressive symptoms and LFCD were observed in left rectal gyrus, left superior frontal gyrus, right supraorbital gyrus, and left inferior temporal gyrus. Positive correlations between depressive symptoms and SFCD were observed in left middle frontal gyrus, left superior frontal gyrus, bilateral superior medial frontal gyrus, left inferior temporal gyrus, and left middle occipital region. Positive correlations between SFCD and loneliness were centered over bilateral lingual gyrus.Conclusion: Depressive symptoms are associated with FCD changes over frontal and temporal regions, which may involve the cognitive control, affective regulation, and default mode networks. Loneliness is associated with FCD changes in bilateral lingual gyri that are known to be important in social cognition. Depressive symptoms and loneliness may be associated with different brain regions in non-demented elderly male.

  8. ["Accepting Demented Minds". Opinion Group, Information and Support on Stigma of Mental Illness on Facebook].

    Science.gov (United States)

    Mancera, Katherine Cárdenas; De Santacruz, Cecilia; Salamanca, Mayra Alejandra

    2014-01-01

    Mental illness is one of the diseases that generates more disability worldwide, and it is estimated that one in four people has or has had this kind of illness during their lives. Since the beginning, mental illness has been frequently linked to stigma and prejudice, which has important implications for the exercise of their human rights, including the right to health, as these preconceptions can delay their early detection and timely treatment. Eliminating stigma requires multiple interventions, in which the participation of people with these illnesses can be very helpful. Social networks portray an alternative for them and for people interested in this topic, helping them interact, clarify some concerns and doubts, and perhaps even modify their exclusion status. Describing the experience of the opinion and support group on Facebook called "Aceptando mentes dementes" ("Accepting Demented Minds"), created for people with mental illnesses, their families and any person interested in this matter, which seeks to make the impact and consequences that result from stigma more noticable. Analysis of qualitative and quantitative data collected over two and a half years of operation of the group, formed by 764 members from different countries. The aims of the group, as regards the spreading of information, interaction through shared experiences, and obtaining support were reached. Social networks allow the creation of communities that share specific needs, such as understanding and support, and all this at low cost. Knowing and being conscious about the stigma linked to mental illness helps raise awareness and generate options for change. To maintain and link it to other resources, the group will be included in the web site www.mentalpuntoapoyo.com. Copyright © 2013 Asociación Colombiana de Psiquiatría. Publicado por Elsevier España. All rights reserved.

  9. Domain-specific cognitive impairment in non-demented Parkinson's disease psychosis.

    Science.gov (United States)

    Hinkle, Jared T; Perepezko, Kate; Bakker, Catherine C; Dawson, Ted M; Johnson, Vanessa; Mari, Zoltan; Marvel, Cherie L; Mills, Kelly A; Pantelyat, Alexander; Pletnikova, Olga; Rosenthal, Liana S; Shepard, Melissa D; Stevens, Daniel A; Troncoso, Juan C; Wang, Jiangxia; Pontone, Gregory M

    2017-05-16

    In Parkinson's disease (PD), psychosis is associated with cognitive impairment that may be more profound in particular cognitive domains. Our goal was to determine whether psychosis in non-demented PD participants is associated with domain-specific cognitive impairment on the Mini-Mental State Exam (MMSE). The Morris K. Udall Parkinson's Disease Research Center of Excellence Longitudinal Study at Johns Hopkins is a prospective study that was initiated in 1998. Clinical assessments are conducted at two-year intervals at the Johns Hopkins Hospital. We analyzed data from 137 enrolled participants with idiopathic PD. Psychosis diagnoses were established by psychiatrist interview per DSM-IV criteria. An incident dementia diagnosis resulted in exclusion from analysis for that evaluation and any future evaluations in that participant. We used logistic regression with generalized estimated equations (GEE) to model the time-varying relationship between MMSE subscale scores and psychosis, adjusting for potential confounding variables identified through univariable analysis. Thirty-one unique psychosis cases were recorded among non-demented participants. Fifty total evaluations with psychosis present were analyzed. In multivariable regressions, psychosis was associated with lower scores on the orientation (relative odds ratio, rOR: 0.73; 95% CI: 0.58-0.93; p = 0.011), language (rOR: 0.64; 95% CI: 0.48-0.86; p = 0.003), and intersecting pentagon (rOR: 0.43; 95% CI: 0.20-0.92 p = 0.030) subscales of the MMSE. In PD, executive dysfunction, disorientation, and impaired language comprehension may be associated with psychosis. Our findings suggest that the corresponding MMSE subscales may be useful in identifying participants with a higher likelihood of developing psychosis. Copyright © 2017 John Wiley & Sons, Ltd. Copyright © 2017 John Wiley & Sons, Ltd.

  10. Rebooting the EdD

    Science.gov (United States)

    Wergin, Jon F.

    2011-01-01

    In this essay, Jon Wergin reminds readers of the philosophical and historical foundations of the doctor of education (EdD) degree. He argues that the EdD should be based, in large part, on John Dewey's progressive ideals of democratization and Paulo Freire's concepts of emancipatory education. Drawing on theories of reflective practice,…

  11. EDS becoms CERN Openlab contributor

    CERN Multimedia

    2007-01-01

    "EDS announced that it has become an official contributor to CERN openlab. The purpose of the joint project beteween CERN and EDS is to carry out research and development in the field of monitoring, management and operation of grid services." (1 page)

  12. EDS becomes CERN Openlab contributor

    CERN Multimedia

    2007-01-01

    "EDS today announced that it has become an official contributor to CERN openlab. The purpose of the joint project between CERN and EDS is to carry out research and development in the field of monitoring, management and operaiton of grid services." (2/3 page)

  13. Study on single step solid state synthesis of WC@C nanocomposite and electrochemical stability of synthesized WC@C & Pt/WC@C for alcohol oxidation (methanol/ethanol)

    Energy Technology Data Exchange (ETDEWEB)

    Singla, Gourav, E-mail: gsinghla@gmail.com; Singh, K., E-mail: kusingh@thapar.edu; Pandey, O.P., E-mail: oppandey@thapar.edu

    2016-04-25

    WC@C nano composite was prepared by a single step solid–state reaction through in situ reduction and carburization of WO{sub 3} in the presence of Mg and activated charcoal. The XRD results and thermodynamics analysis showed that the optimization of reaction temperature facilitates the reduction as well as carburization of tungsten oxide(s) at different reaction temperature. Thermogravimetric analysis of the product was done to assess the thermal stability in air. The Raman spectroscopy was used to find out the nature (amorphous/graphitic) of carbon in the obtained phase. The N{sub 2} adsorption–desorption measurement showed a narrow pore size distribution from 3 to 4 nm with BET surface area of up to 522.5 m{sup 2}/g. TEM/HRTEM images confirmed formation of the WC nano particles with spherical morphology. Electrochemical stability of pure and platinized carbide sample (Pt/WC) has been investigated using cyclic voltammetry in acidic media for alcohol (methanol and ethanol) oxidation. - Highlights: • Tungsten carbide nano powder was synthesized using charcoal as carbon source. • Formation of WC occurs through the formation of lower tungsten oxide. • CO{sub 2}/CO ratio effect the formation of WC. • Mesoporous tungsten carbide with surface areas 522.5 m{sup 2}/g obtained by using charcoal. • Pt modified WC powder showed higher electrochemical stability.

  14. Leaching Behavior of Al, Co and W from the Al-Alloying Treated WC-Co Tool as a New Recycling Process for WC Hard Scrap

    Directory of Open Access Journals (Sweden)

    Jaeryeong Lee

    2016-07-01

    Full Text Available The Al-alloying treated tungsten carbide (WC-Co tool was subjected to grinding using a jaw crusher and planetary mill followed by three wet chemical treatment steps to establish an effective recycling process for WC scraps, especially those generated as bulky and hard scrap. This alloyed WC tool was readily ground to a powder of 1 mm or less and divided into two portions that were 150 µm in size. The wet chemical treatments enabled us to recover W to 69.44% from the under-sized 150 µm and also obtain WC powders from the over-sized 150 µm with a high purity of 98.9% or more.

  15. High-Temperature Exposure Studies of HVOF-Sprayed Cr3C2-25(NiCr)/(WC-Co) Coating

    Science.gov (United States)

    Singh, Harpreet; Kaur, Manpreet; Prakash, Satya

    2016-08-01

    In this research, development of Cr3C2-25(NiCr) + 25%(WC-Co) composite coating was done and investigated. Cr3C2-25(NiCr) + 25%(WC-Co) composite powder [designated as HP2 powder] was prepared by mechanical mixing of [75Cr3C2-25(NiCr)] and [88WC-12Co] powders in the ratio of 75:25 by weight. The blended powders were used as feedstock to deposit composite coating on ASTM SA213-T22 substrate using High Velocity Oxy-Fuel (HVOF) spray process. High-temperature oxidation/corrosion behavior of the bare and coated boiler steels was investigated at 700 °C for 50 cycles in air, as well as, in Na2SO4-82%Fe2(SO4)3 molten salt environment in the laboratory. Erosion-corrosion behavior was investigated in the actual boiler environment at 700 ± 10 °C under cyclic conditions for 1500 h. The weight-change technique was used to establish the kinetics of oxidation/corrosion/erosion-corrosion. X-ray diffraction, field emission-scanning electron microscopy/energy-dispersive spectroscopy (FE-SEM/EDS), and EDS elemental mapping techniques were used to analyze the exposed samples. The uncoated boiler steel suffered from a catastrophic degradation in the form of intense spalling of the scale in all the environments. The oxidation/corrosion/erosion-corrosion resistance of the HVOF-sprayed HP2 coating was found to be better in comparison with standalone Cr3C2-25(NiCr) coating. A simultaneous formation of protective phases might have contributed the best properties to the coating.

  16. Macroparticle generation in DC arc discharge from a WC cathode

    Science.gov (United States)

    Zhirkov, Igor; Polcik, Peter; Kolozsvári, Szilard; Rosen, Johanna

    2017-03-01

    We have studied macroparticle generation from a tungsten carbide cathode used in a dc vacuum arc discharge. Despite a relatively high decomposition/melting point (˜3100 K), there is an intensive generation of visible particles with sizes in the range 20-35 μm. Visual observations during the discharge and scanning electron microscopy of the cathode surface and of collected macroparticles indicate a new mechanism for particle formation and acceleration. Based on the W-C phase diagram, there is an intensive sublimation of carbon from the melt resulting from the cathode spot. The sublimation supports the formation of a sphere, which is accelerated upon an explosion initiated by Joule heating at the critical contact area between the sphere and the cathode body. The explosive nature of the particle acceleration is confirmed by surface features resembling the remains of a splash on the droplet surface.

  17. Adhesion at WC/diamond interfaces - A theoretical study

    Science.gov (United States)

    Padmanabhan, Haricharan; Rao, M. S. Ramachandra; Nanda, B. R. K.

    2015-06-01

    We investigate the adhesion at the interface of face-centered tungsten-carbide (001) and diamond (001) from density-functional calculations. Four high-symmetry model interfaces, representing different lattice orientations for either side of the interface, are constructed to incorporate different degrees of strain arising due to lattice mismatch. The adhesion, estimated from the ideal work of separation, is found to be in the range of 4 - 7 J m-2 and is comparable to that of metal-carbide interfaces. Maximum adhesion occurs when WC and diamond slabs have the same orientation, even though such a growth induces large epitaxial strain at the interface. From electronic structure calculations, we attribute the adhesion to covalent interaction between carbon p-orbitals as well as partial ionic interaction between the tungsten d- and carbon p-orbitals across the interface.

  18. Adhesion at WC/diamond interfaces - A theoretical study

    Energy Technology Data Exchange (ETDEWEB)

    Padmanabhan, Haricharan [Department of Engineering Design, Indian Institute of Technology Madras, Chennai – 600036 (India); Rao, M. S. Ramachandra [Department of Physics and Nano-Functional Materials Technology Centre, Indian Institute of Technology Madras, Chennai – 600036 (India); Nanda, B. R. K., E-mail: nandab@iitm.ac.in [Department of Physics, Indian Institute of Technology Madras, Chennai – 600036 (India)

    2015-06-24

    We investigate the adhesion at the interface of face-centered tungsten-carbide (001) and diamond (001) from density-functional calculations. Four high-symmetry model interfaces, representing different lattice orientations for either side of the interface, are constructed to incorporate different degrees of strain arising due to lattice mismatch. The adhesion, estimated from the ideal work of separation, is found to be in the range of 4 - 7 J m{sup −2} and is comparable to that of metal-carbide interfaces. Maximum adhesion occurs when WC and diamond slabs have the same orientation, even though such a growth induces large epitaxial strain at the interface. From electronic structure calculations, we attribute the adhesion to covalent interaction between carbon p-orbitals as well as partial ionic interaction between the tungsten d- and carbon p-orbitals across the interface.

  19. Influence of WC addition on the microstructure and mechanical properties of NbC-Co cermets

    Energy Technology Data Exchange (ETDEWEB)

    Huang, S.G. [Department of Metallurgy and Materials Engineering (MTM), Katholieke Universiteit Leuven, Kasteelpark Arenberg 44, B-3001 Heverlee (Belgium); Li, L. [School of Material Science and Engineering, Shanghai University, 149 Yanchang Road, Shanghai 200072 (China); Van der Biest, O. [Department of Metallurgy and Materials Engineering (MTM), Katholieke Universiteit Leuven, Kasteelpark Arenberg 44, B-3001 Heverlee (Belgium); Vleugels, J. [Department of Metallurgy and Materials Engineering (MTM), Katholieke Universiteit Leuven, Kasteelpark Arenberg 44, B-3001 Heverlee (Belgium)]. E-mail: Jozef.Vleugels@mtm.kuleuven.be

    2007-03-14

    NbC-24.5 wt.% Co cermets with up to 30 wt.% WC were obtained by solid state hot pressing at 1300 {sup o}C under a pressure of 45 MPa for 10 min and pressureless liquid phase sintering at 1360 {sup o}C for 60 min. The effect of WC addition on the microstructure and mechanical properties of NbC-Co based cermets was investigated. The hot pressed cermets exhibited interconnected and irregular niobium carbide (NbC) or (Nb,W)C grains, whereas the shape of the NbC grains changed from faceted with rounded corners to spherical, as the WC content increased in the pressureless sintered cermets. The undissolved WC increased with increasing WC addition. A clear core/rim structure was observed in the hot pressed cermets with 10-30 wt.% WC additions, whereas this structure was gradually eliminated when pressureless sintering. The hardness remains nearly constant whereas the fracture toughness slightly increases with increasing WC addition. The dissolution of WC in the Co binder and NbC grains, as well as the formation of a solid solution (Nb,W)C phase were supported by thermodynamic calculations.

  20. Stability and electrocatalytic activity for oxygen reduction in WC + Ta catalyst

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Kunchan; Ishihara, Akimitsu; Mitsushima, Shigenori; Kamiya, Nobuyuki; Ota, Ken-ichiro

    2004-09-01

    Tantalum (Ta)-added tungsten carbide (WC) (WC+Ta) was examined in order to obtain surperior characteristics in stability and electrocatalytic activity for the oxygen reduction reaction (ORR) in acid electrolyte. The stability and the electrocatalytic activity of the WC+Ta catalyst were electrochemically investigated and compared to the pure WC. It was proved that the stability of the tungsten carbide was significantly increased by the addition of tantalum compared to the pure WC. The enhanced stability might be due to the formation of the W-Ta alloy in the WC+Ta catalyst. The reduction current of the WC+Ta catalyst for the ORR was observed at a potential of 0.8 V (versus dynamin hydrogen eletrode (DHE)) or less noble potential. This value was about 0.35 V higher than that of the pure WC. The enhanced electrocatalytic activity for the ORR might be caused by the presence of tungsten carbide, which exists on the surface and/or sub-surface.

  1. An alternative approach to estimate the W/C ratio of hardened concrete using image analysis

    NARCIS (Netherlands)

    Valcke, S.; Nijland, T.G.; Larbi, J.A.

    2009-01-01

    The water cement (w/c) ratio is a typical quality parameter for concrete. The NT Build 361 Nordtest method is a standard for estimating the w/c ratio in hardened concrete and is based on the relationship between the ilc ratio and the capillary porosity in the cement paste. The latter can be estimate

  2. The development of a multidisciplinary fall risk evaluation tool for demented nursing home patients in the Netherlands

    Directory of Open Access Journals (Sweden)

    de Witte Luc P

    2006-03-01

    Full Text Available Abstract Background Demented nursing home patients are at high risk for falls. Falls and associated injuries can have a considerable influence on the autonomy and quality of life of patients. The prevention of falls among demented patients is therefore an important issue. In order to intervene in an efficient way in this group of patients, it is important to systematically evaluate the fall risk profile of each individual patient so that for each patient tailor-made preventive measures can be taken. Therefore, the objective of the present study is to develop a feasible and evidence based multidisciplinary fall risk evaluation tool to be used for tailoring preventive interventions to the needs of individual demented patients. Methods To develop this multidisciplinary fall risk evaluation tool we have chosen to combine scientific evidence on the one hand and experts' opinions on the other hand. Firstly, relevant risk factors for falling in elderly persons were gathered from the literature. Secondly, a group of Dutch experts in the field of falls and fall prevention in the elderly were consulted to judge the suitability of these risk factors for use in a multidisciplinary fall risk evaluation tool for demented nursing home patients. Thirdly, in order to generate a compact list of the most relevant risk factors for falling in demented elderly, all risk factors had to fulfill a set of criteria indicating their relevance for this specific target population. Lastly the final list of risk factors resulting from the above mentioned procedure was presented to the expert group. The members were also asked to give their opinion about the practical use of the tool. Results The multidisciplinary fall risk evaluation tool we developed includes the following items: previous falls, use of medication, locomotor functions, and (correct choice and use of assistive and protective devices. The tool is developed for the multidisciplinary teams of the nursing homes

  3. TechEdSat Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The overall goal of the Technical Education Satellite (TechEdSat) is to employ a small spacecraft to evaluate, demonstrate, and validate two new technologies for...

  4. Nanoparticles of WC-Co, WC, Co and Cu of relevance for traffic wear particles - Particle stability and reactivity in synthetic surface water and influence of humic matter.

    Science.gov (United States)

    Hedberg, Yolanda S; Hedberg, Jonas F; Isaksson, Sara; Mei, Nanxuan; Blomberg, Eva; Wold, Susanna; Odnevall Wallinder, Inger

    2017-02-11

    Studded tyres made of tungsten carbide cobalt (WC-Co) are in the Northern countries commonly used during the winter time. Tungsten (W)-containing nano- and micron-sized particles have been detected close to busy roads in several European countries. Other typical traffic wear particles consist of copper (Cu). The aims of this study were to investigate particle stability and transformation/dissolution properties of nanoparticles (NPs) of WC-Co compared with NPs of tungsten carbide (WC), cobalt (Co), and Cu. Their physicochemical characteristics (primarily surface oxide and charge) are compared with their extent of sedimentation and metal release in synthetic surface water (SW) with and without two different model organic molecules, 2,3- and 3,4-dihydroxybenzoic acid (DHBA) mimicking certain sorption sites of humic substances, for time periods up to 22 days. The WC-Co NPs possessed a higher electrochemical and chemical reactivity in SW with and without DHBA molecules as compared with NPs of WC, Co, and Cu. Co was completely released from the WC-Co NPs within a few hours of exposure, although it remained adsorbed/bonded to the particle surface and enabled the adsorption of negatively charged DHBA molecules, in contrast with the WC NPs (no adsorption of DHBA). The DHBA molecules were found to rapidly adsorb on the Co and Cu NPs. The sedimentation of the WC and WC-Co NPs was not influenced by the presence of the 2,3- or 3,4-DHBA molecules. A slight influence (slower sedimentation) was observed for the Co NPs, and a strong influence (slower sedimentation) was observed for the Cu NPs in SW with 2,3-DHBA compared with SW alone. The extent of metal release increased in the order: WC < Cu < Co < WC-Co NPs. All NPs released more than 1 wt-% of their metal total mass. The release from the Cu NPs was most influenced by the presence of DHBA molecules.

  5. Neuropsychiatric co-morbidities in non-demented Parkinson′s disease

    Directory of Open Access Journals (Sweden)

    Nirendra Kumar Rai

    2015-01-01

    Full Text Available Objective: To evaluate neuropsychiatric co-morbidities (depression, psychosis and anxiety in non-demented patients with Parkinson′s disease (PD. Background: Non-motor symptoms like neuropsychiatric co-morbidities are common in Parkinson′s disease and may predate motor symptoms. Currently there is scarcity of data regarding neuropsychiatry manifestations in Indian patients with PD. Methods: In this cross-sectional study consecutive 126 non-demented patients with PD (MMSE ≥25 were enrolled. They were assessed using Unified Parkinson′s disease rating scale (UPDRS, Hoehn & Yahr (H&Y stage, Schwab and England (S&E scale of activity of daily life. Mini-international neuropsychiatric interview (MINI was used for diagnosis of depression, psychosis and anxiety. Beck′s depression inventory (BDI, Brief psychiatric rating scale (BSRS and Hamilton rating scale for anxiety (HAM-A scales were used for assessment of severity of depression, psychosis and anxiety respectively. Results: Mean age and duration of disease was 57.9 ± 10.9 years and 7.3 ± 3.6 years respectively. At least one of the neuropsychiatric co-morbidity was present in 64% patients. Depression, suicidal risk, psychosis and anxiety were present in 43.7%, 31%, 23.8% and 35.7% respectively. Visual hallucinations (20.6% were most frequent, followed by tactile (13.5%, auditory (7.2% and olfactory hallucinations (1.6%. Patients with depression had higher motor disability (UPDRS-motor score 33.1 ± 14.0 vs 27.3 ± 13.3; and UPDRS-total 50.7 ± 21.8 vs 41.0 ± 20.3, all p values <0.05. Patients with psychosis were older (63.6 ± 8.0 years vs 56.1 ± 11.1 years, p < 0.05 and had longer duration of illness (8.6 ± 3.4 years vs 6.9 ± 3.5, p < 0.05. Conclusions: About two third patients with Parkinson′s disease have associated neuropsychiatric co-morbidities. Depression was more frequent in patients with higher disability and psychosis with longer duration of disease and older age. These co

  6. Structure and hardness of a hard metal alloy prepared with a WC powder synthesized at low temperature

    Energy Technology Data Exchange (ETDEWEB)

    Costa, F.A. da [Programa de Pos-Graduacao em Ciencia e Engenharia de Materiais, UFRN, Campus Universitario, 59072-970 Natal, RN (Brazil)], E-mail: francineac@yahoo.com; Medeiros, F.F.P. de [Programa de Pos-Graduacao em Ciencia e Engenharia de Materiais, UFRN, Campus Universitario, 59072-970 Natal, RN (Brazil); Silva, A.G.P. da [Laboratorio de Materiais Avancados, UENF, 28015-620 Campos de Goytacazes, RJ (Brazil); Gomes, U.U. [Departamento de Fisica Teorica e Experimental, UFRN, Campus Universitario, 59072-970 Natal, RN (Brazil); Filgueira, M. [Laboratorio de Materiais Avancados, UENF, 28015-620 Campos de Goytacazes, RJ (Brazil); Souza, C.P. de [Laboratorio de Termodinamica e Reatores, UFRN, Campus Universitario, 59072-970 Natal, RN (Brazil)

    2008-06-25

    The structure and hardness of a WC-10 wt% Co alloy prepared with an experimental WC powder are compared with those of another alloy of the same composition produced under the same conditions and prepared with a commercial WC powder. The experimental WC powder was synthesized by a gas-solid reaction between APT and methane at low temperature and the commercial WC powder was conventionally produced by a solid-solid reaction between tungsten and carbon black. WC-10 wt% Co alloys with the two powders were prepared under the same conditions of milling and sintering. The structure of the sample prepared with the experimental WC powder is homogeneous and coarse grained. The structure of the sample prepared with the commercial powder is heterogeneous. Furthermore the size and shape of the WC grains are significantly different.

  7. Age- dependent effect of Alzheimer’s risk variant of CLU on EEG alpha rhythm in non-demented adults

    Directory of Open Access Journals (Sweden)

    Natalya ePonomareva

    2013-12-01

    Full Text Available Polymorphism in the genomic region harboring the CLU gene (rs11136000 has been associated with the risk for Alzheimer’s disease (AD. CLU C allele is assumed to confer risk for AD and the allele T may have a protective effect.We investigated the influence of the AD-associated CLU genotype on a common neurophysiological trait of brain activity (resting-state alpha-rhythm activity in non-demented adults and elucidated whether this influence is modified over the course of aging. We examined quantitative EEG (qEEG in cohort of non-demented individuals (age range 20-80 divided into young (age range 20-50 and old (age range 51-80 cohorts and stratified by CLU polymorphism. To rule out the effect of the ApoE genotype on EEG characteristics, only subjects without the ApoE epsilon4 allele were included in the study.The homozygous presence of the AD risk variant CLU CC in non-demented subjects was associated with an increase of alpha3 absolute power. Moreover, the influence of CLU genotype on alpha3 was found to be higher in the subjects older than 50 years of age. The study also showed age-dependent alterations of alpha topographic distribution that occur independently of the CLU genotype.The increase of upper alpha power has been associated with hippocampal atrophy in patients with mild cognitive impairment (Moretti et al., 2012a. In our study, the CLU CC- dependent increase in upper alpha rhythm, particularly enhanced in elderly non-demented individuals, may imply that the genotype is related to preclinical dysregulation of hippocampal neurophysiology in aging and that this factor may contribute to pathogenesis of AD.

  8. Caregiver and environmental variables related to difficult behaviors in institutionalized, demented elderly persons.

    Science.gov (United States)

    Burgener, S C; Jirovec, M; Murrell, L; Barton, D

    1992-07-01

    This study describes the relationship between caregiver and elder behavior in institutionalized, cognitively impaired, elderly persons. A repeated-measures design was used to observe interactive behaviors between caregivers and demented elders within three caregiving situations (dressing, toileting, and bathing) and an interpersonal contact in two long-term care facilities. During observations, the caregiver's behaviors were rated using the Interaction Behavior Measure and Health Professional's-Geriatric Patient Behavior Rating scale, whereas the elder's behaviors were rated using a modified version of the Interaction Behavior Measure. The study included 116 subjects (58 elders and 58 caregivers), with each unique caregiver/elder pair being observed in the four situations. All elder behaviors varied according to situation type, with the most difficult elder behaviors occurring during bathing. Ten of the 12 caregiver behaviors included in the analysis varied by situation type. Significant relationships were systematically found between the caregiver's relaxed and smiling behavior and the elder's calm/functional behaviors, r = .42 (dressing) to r = .46 (toileting) for caregiver relaxed behavior and r = .34 (bathing) to r = .58 (dressing) for smiling. The elder's behavior did not vary by type of nursing unit (special dementia unit or general nursing unit), or interruptions to the interaction.

  9. The dement in the community: Social work practice with people with dementia revisited.

    Science.gov (United States)

    Manthorpe, Jill

    2016-09-01

    While social work practice with people with dementia and their families has a long but largely hidden history, it is an emerging area of specialism. The increased incidence, prevalence and recognition of dementia suggest that this area of practice will expand and so learning from previous practice may offer helpful insights. This paper describes and reflects upon social work practice with 'dements' in the 1950s in England. It draws on a reading of a small book written by a psychiatric social worker, Miss M (Muriel) H Bree, outlining her role in providing after-care to patients with neuro-syphilis who had been discharged from hospital to live with their families between 1942 and 1952 through her consideration of 275 case records and seven illustrative case studies. As a historical document, Bree's account presents a rich description of the patients and their social circumstances in post-war Britain; an account of practice from a hospital based setting that reached into the community, and of the engagement of a social worker with her clients and their family members. Threads and continuities with contemporary social work practice with people with dementia are explored; particularly work with family carers, younger people with dementia, and the value placed upon continuity of care.

  10. Microstructure and Abrasive Wear Performance of Ni-Wc Composite Microwave Clad

    Science.gov (United States)

    Bansal, Amit; Zafar, Sunny; Sharma, Apurbba Kumar

    2015-10-01

    In the present work, Ni-WC powder was deposited on mild steel substrate to develop clads through microwave hybrid heating technique. The cladding trials were carried out in an industrial microwave applicator at 1.1 kW for 540 s. The Ni-WC composite clads were characterized for microstructure and abrasive wear performance through combination of x-ray diffraction, electron and optical microscopy, microhardness, and wear tests. Phase analysis of the Ni-WC clad indicated the presence of stable carbides such as WC, W2C, Ni2W4C, and Fe6W6C. The microstructure study of the clad layer revealed the presence of a uniformly distributed interlocked WC-based reinforcement embedded in the Ni-based matrix. The average Vicker's microhardness in the clad layer was observed to be 1028 ± 90 HV, which was approximately three times the microhardness of the substrate. Abrasive wear resistance of the microwave clads was superior to the MS substrate. Abrasion was the main wear mechanism in the Ni-WC clads and the substrate samples. However, the presence of WC-based reinforcement in the composite clads reduced microcutting, resulting in enhanced wear resistance.

  11. Ultrafine WC-Ni cemented carbides fabricated by spark plasma sintering

    Energy Technology Data Exchange (ETDEWEB)

    Rong Huiyong [School of Engineering and Technology, China University of Geosciences at Beijing, Beijing 100083 (China); Peng Zhijian, E-mail: pengzhijian@cugb.edu.cn [School of Engineering and Technology, China University of Geosciences at Beijing, Beijing 100083 (China); Ren Xiaoyong; Peng Ying; Wang Chengbiao; Fu Zhiqiang [School of Engineering and Technology, China University of Geosciences at Beijing, Beijing 100083 (China); Qi Longhao; Miao Hezhuo [State Key Laboratory of New Ceramics and Fine Processing, Tsinghua University, Beijing 100084 (China)

    2012-01-15

    Highlights: Black-Right-Pointing-Pointer Ultrafine WC-Ni cemented carbides with average WC grain size of about 330 nm prepared by combination of sparking plasma sintering and grain growth inhibitors. Black-Right-Pointing-Pointer Very short mean free path of about 22 nm for crack in metal binder of the obtained materials. Black-Right-Pointing-Pointer Higher hardness than those of WC-Co cemented carbide counterparts sintered by rapid sintering. Black-Right-Pointing-Pointer Observation of fracture along metal binder and no carbon-carbon fracture face. - Abstract: With VC and TaC as WC grain growth inhibitors, ultrafine WC-Ni cemented carbides with different fractions (6-10 wt%) of binder metal nickel were fabricated by utilizing high energy milling together with spark plasma sintering. In the obtained samples, only WC and Ni phases were detected in X-ray diffraction limit. The microstructure of the specimens was examined on fractural, polished, and polished/etched surfaces by scanning electron microscopy, and the results revealed that the average WC grain size of the WC-Ni cemented carbides was about 330 nm, and there were lots of micro-pores in the samples. The relative density of the samples was all higher than 92%. But the measurement of hardness and flexural strength indicated that the existence of micro-pores had no significant influence on the performance of the obtained materials. On the basis of observation on the micro-fracture surface of the samples, it was found that fractures occurred along the binder metal, and the obtained ultrafine WC-Ni cemented carbides showed a very short binder mean free path (about 22 nm), thus resulting in excellent performance in mechanical strength.

  12. An Ultraviolet to Mid-Infrared Study of the Physical and Wind Properties of HD 164270 (WC9) and Comparison to BD+30 3639 ([WC9])

    CERN Document Server

    Crowther, P; Smith, J D; Crowther, Paul; Morris, Pat; Smith, JD

    2006-01-01

    We present new Spitzer IRS observations of HD164270 (WC9, WR103). A quantitative analysis of the UV, optical, near- and mid-IR spectrum of HD164270 is presented, allowing for line blanketing and wind clumping, revealing T* ~ 48kK, log L/L_sun ~ 4.9, dM/dt ~ 1e-5 M_sun/yr for a volume filling factor of f \\~ 0.1. Our models predict that He is partially recombined in the outer stellar wind, such that recent radio-derived mass-loss rates of WC9 stars have been underestimated. We obtain C/He ~ 0.2 and O/He ~ 0.01 by number from optical diagnostics. Mid-IR fine structure lines of [NeII] 12.8 and [SIII] 18.7micron are observed, with [NeIII] and [SIV] absent. From these we obtain Ne/He ~ Ne^+/He = 2.2e-3 by number, 7 times higher than the Solar value (as recently derived by Asplund et al.), and S/He ~ S^2+/He = 5.1e-5 by number. From a comparison with similar results for other WC subtypes we conclude that WC9 stars are as chemically advanced as earlier subtypes. We consider why late WC stars are exclusively observed ...

  13. Polyporous C@WC1-x composite and its electrocatalytic activity for p-nitrophenol reduction

    Institute of Scientific and Technical Information of China (English)

    Hua Jun Zheng; Ai Mei Yu; Chun An Ma

    2011-01-01

    The polyporous carbon supported tungsten carbide (polyporous C@WC1-x) composite was prepared using hexagonal silica MCM-41 as the hard template by raw material solution impregnation, mechanical milling and simultaneous reduction and carbonization by temperature programming in mixture gas (CH4/H2). The structure and morphology of polyporous C@WC1-x composite were studied via X-ray diffraction, transmission electron microscopy and so on. The electrocatalytic property was tested for the electroreduction of p-nitrophenol (PNP) in neutral media. Results revealed that the composite is consisted of polyporous carbon and nanocrystalline WC1-x, possessing good electrocatalytic activity in the reaction of PNP reduction.

  14. Interface behavior study of WC92-Co8 coating produced by electrospark deposition

    Science.gov (United States)

    Ruijun, Wang; Yiyu, Qian; Jun, Liu

    2005-02-01

    WC92-Co8 coating produced by electrospark deposition effectively improves the surface performance of the substrate. The behavior of the interface between the WC92-Co8 coating and the substrate is studied in this paper. The high-melting-point WC92-Co8 was deposited onto the surface of Ti alloy, and the coating was usually more than 50 μm thick. The surface of the coating is mainly composed of TiC and W 2C besides a small amount of W, and its micro hardness reaches HV1129. The coating dramatically improves the performance of the substrate.

  15. [Psychiatric distress and related risk factors of family caregivers who care for the demented elderly at home].

    Science.gov (United States)

    Doi, Y; Ogata, K

    2000-01-01

    The objectives of our study were to assess psychiatric distress of caregivers who had been caring for the demented elderly at home and to examine the association of caregivers' psychiatric distress with putative risk factors. Subjects were 294 caregivers living in Amakusa, Kumamoto Prefecture of Japan, whose spouses, parents or other family members were registered at Amakusa Public Health Center as demented elderly. In 1998, Survey on Caregivers' Mental Health was conducted using the General Health Questionnaire (GHQ12) as a measurement for general psychiatric state of caregivers. Two hundred and eighty-two caregivers responded to interviews with complaints of the following psychological symptoms: feelings of unhappiness (55.7%), of stress (41.8%), insomnia (29.4%) and depressed mood (29.1%). Seventy-six caregivers (27.2%) were identified as being above the cut-off point 4 for psychiatric distress caseness. Multivariate logistic regression analysis indicated caregivers' psychiatric distress was statistically associated with caregivers' age, the caregivers' perception of the severity of dementia, the number of years devoted to caregiving at home and perceived financial state. Being 50 to 69 years (OR = 0.37, 95% CI: 0.17-0.81) and being 70 years or older (OR = 0.35, 95% CI: 0.14-0.83) were negatively associated with caseness as compared to being 20 to 49 years. Caseness was positively related to the severity of the elderly's demented state (OR = 6.93, 95% CI: 1.99-24.19), 1 year to 2 years devoted to caregiving at home (OR = 3.26, 95% CI: 1.02-10.38), no family or social support (OR = 2.99, 95% CI: 1.12-7.96) and lower perceived financial state (always OR = 6.99, 95% CI: 2.77-17.64, sometimes OR = 2.41, 95% CI: 1.19-4.85). Reduction of caregivers' psychiatric distress is important for not merely the enhancement of quality of care for demented elders and caregivers' life but for the prevention of elder abuse or neglect. Our study suggests that a comprehensive

  16. The Corrosion and Wear Performance of Microcrystalline WC-10Co-4Cr and Near-Nanocrystalline WC-17Co High Velocity Oxy-Fuel Sprayed Coatings on Steel Substrate

    Science.gov (United States)

    Saha, Gobinda C.; Khan, Tahir I.

    2010-11-01

    The study of near-nanocrystalline cermet composite coating was performed by depositing near-nanocrystalline WC-17Co powder using the high velocity oxy-fuel spraying technique. The WC-17Co powder consists of a core with an engineered near-nano-scale WC dispersion with a mean grain size 427 nm. The powder particle contains 6 wt pct of the ductile phase Co matrix mixed into the core to ensure that the reinforcing ceramic phase WC material is discontinuous to limit debridement during wear, while the remainder of the binding phase (11 wt pct) is applied as a coating on the powder particle to improve the ductility. The tribological properties of the coating, in terms of corrosion resistance, microhardness, and sliding abrasive wear, were studied and compared with those of an industrially standard microcrystalline WC-10Co-4Cr coating with a WC mean grain size 3 μm. Results indicated that the WC-17Co coating had superior wear and corrosion resistance compared to the WC-10Co-4Cr coating. The engineered WC-17Co powder with a duplex Co layer had prevented significant decarburization of the WC dispersion in the coating, thereby reducing the intersplat microporosity necessary for initiating microgalvanic cells. The improved wear resistance was attributed to the higher hardness value of the near-nanocrystalline WC-17Co coating.

  17. Abrasion of ultrafine WC-Co by fine abrasive particles

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Abrasive wear of a series of WC-(5%-14%, mass fiaction)Co hardmetals was investigated employing coarse and fine SiC abrasive under two-body dry abrasion conditions with pin-on-disc and edge-on-disc test arrangements. Unexpectedly, it is found that submicron grades demonstrate substantially higher wear rates comparing with the coarse grades if fine abrasive is utilized in pin-on-disc tests. Such a behavior is attributed to changes in a ratio of abrasive size to size of hard phase as finer abrasive is used.The edge-on-disc test demonstrates that edge wear may be described in two stages with the highest wear rates at the beginning stage.This behavior is associated with a transition of wear mechanisms as edge is wider due to wear. Compared with the ultrafine grades of the same Co content, the coarse grades demonstrate higher wear rates at the beginning, but lower wear rates at the final stage. Wear rates and mechanisms observed at final stage correlate well to the results observed for pin-on-disc tests employing fine abrasive.

  18. HRTEM and Nanoindentation Studies of Bulk WC Nanocrystalline Materials Prepared by Spark Plasma Sintering of Ball-Milled Powders

    Science.gov (United States)

    Sherif El-Eskandarany, M.; Al-Hazza, Abdulsalam; Al-Hajji, L. A.

    2017-01-01

    In the present work, mechanical milling technique using a high-energy ball mill was employed for preparing of nanoscaled WC grains powders with an average grain size of 7 nm in diameters of WC. The present study demonstrates a successful consolidation process achieved at 1250 °C for sintering of ball-milled WC powders into full dense bulk buttons (above 99.6%), using SPS technique. The as-consolidated WC bulk nanocrystalline buttons revealed high hardness value ( 24 GPa) with low elastic modulus ( 332 GPa). Moreover, they possessed a high fracture toughness (15 MPa m1/2) that has never been reported for pure WC.

  19. Ultrafine WC-Co Composite Powder Preparation by Chemical Precipitation Method%化学沉淀法制备超细WC-Co复合粉的研究

    Institute of Scientific and Technical Information of China (English)

    王玉香; 文小强; 周健

    2012-01-01

    Using ammonium paratungstate and cobalt nitrate as raw materials, ultrafine WC-Co composite powder was prepared by direct reduction&carburization method under the vacuum condition. The effects of feed concentration, reaction temperature and pH value of the mother liquor after reaction on precursor oxide particle size and yield are studied. The morphology and composition of the ultrafine WC-Co composite powder are measured by SEM and XRD. Results show the ultrafine WC-Co composite powder is characterized by regular morphology and good dispersion. This method has advantages of low cost of raw material and simple process.%以钨酸铵和硝酸钴为原料,经化学沉淀后煅烧,然后在真空气氛下直接还原碳化制得超细WC-Co复合粉.考察了化学沉淀过程中料液浓度、反应温度和反应后母液的pH值等因素对所得前驱体氧化物粒度及收率的影响.用XRD和扫描电镜对所得超细WC-Co复合粉进行了分析和观察.结果表明,采用这种方法可以制取形貌规则,分散性良好的超细WC-Co复合粉,并且此法原料成本低,工艺简单,过程易控.

  20. Mitigating Higher Ed Cyber Attacks

    Science.gov (United States)

    Rogers, Gary; Ashford, Tina

    2015-01-01

    In this presentation we will discuss the many and varied cyber attacks that have recently occurred in the higher ed community. We will discuss the perpetrators, the victims, the impact and how these institutions have evolved to meet this threat. Mitigation techniques and defense strategies will be covered as will a discussion of effective security…

  1. Neuronal dysfunction and disconnection of cortical hubs in non-demented subjects with elevated amyloid burden

    Science.gov (United States)

    Drzezga, Alexander; Van Dijk, Koene R. A.; Sreenivasan, Aishwarya; Talukdar, Tanveer; Sullivan, Caroline; Schultz, Aaron P.; Sepulcre, Jorge; Putcha, Deepti; Greve, Doug; Johnson, Keith A.; Sperling, Reisa A.

    2011-01-01

    Disruption of functional connectivity between brain regions may represent an early functional consequence of β-amyloid pathology prior to clinical Alzheimer's disease. We aimed to investigate if non-demented older individuals with increased amyloid burden demonstrate disruptions of functional whole-brain connectivity in cortical hubs (brain regions typically highly connected to multiple other brain areas) and if these disruptions are associated with neuronal dysfunction as measured with fluorodeoxyglucose-positron emission tomography. In healthy subjects without cognitive symptoms and patients with mild cognitive impairment, we used positron emission tomography to assess amyloid burden and cerebral glucose metabolism, structural magnetic resonance imaging to quantify atrophy and novel resting state functional magnetic resonance imaging processing methods to calculate whole-brain connectivity. Significant disruptions of whole-brain connectivity were found in amyloid-positive patients with mild cognitive impairment in typical cortical hubs (posterior cingulate cortex/precuneus), strongly overlapping with regional hypometabolism. Subtle connectivity disruptions and hypometabolism were already present in amyloid-positive asymptomatic subjects. Voxel-based morphometry measures indicate that these findings were not solely a consequence of regional atrophy. Whole-brain connectivity values and metabolism showed a positive correlation with each other and a negative correlation with amyloid burden. These results indicate that disruption of functional connectivity and hypometabolism may represent early functional consequences of emerging molecular Alzheimer's disease pathology, evolving prior to clinical onset of dementia. The spatial overlap between hypometabolism and disruption of connectivity in cortical hubs points to a particular susceptibility of these regions to early Alzheimer's-type neurodegeneration and may reflect a link between synaptic dysfunction and functional

  2. Gray and White Matter Contributions to Cognitive Frontostriatal Deficits in Non-Demented Parkinson's Disease.

    Directory of Open Access Journals (Sweden)

    Catherine C Price

    Full Text Available This prospective investigation examined: 1 processing speed and working memory relative to other cognitive domains in non-demented medically managed idiopathic Parkinson's disease, and 2 the predictive role of cortical/subcortical gray thickness/volume and white matter fractional anisotropy on processing speed and working memory.Participants completed a neuropsychological protocol, Unified Parkinson's Disease Rating Scale, brain MRI, and fasting blood draw to rule out vascular contributors. Within group a priori anatomical contributors included bilateral frontal thickness, caudate nuclei volume, and prefrontal white matter fractional anisotropy.Idiopathic Parkinson's disease (n = 40; Hoehn & Yahr stages 1-3 and non-Parkinson's disease 'control' peers (n = 40 matched on demographics, general cognition, comorbidity, and imaging/blood vascular metrics. Cognitively, individuals with Parkinson's disease were significantly more impaired than controls on tests of processing speed, secondary deficits on working memory, with subtle impairments in memory, abstract reasoning, and visuoperceptual/spatial abilities. Anatomically, Parkinson's disease individuals were not statistically different in cortical gray thickness or subcortical gray volumes with the exception of the putamen. Tract Based Spatial Statistics showed reduced prefrontal fractional anisotropy for Parkinson's disease relative to controls. Within Parkinson's disease, prefrontal fractional anisotropy and caudate nucleus volume partially explained processing speed. For controls, only prefrontal white matter was a significant contributor to processing speed. There were no significant anatomical predictors of working memory for either group.Caudate nuclei volume and prefrontal fractional anisotropy, not frontal gray matter thickness, showed unique and combined significance for processing speed in Parkinson's disease. Findings underscore the relevance for examining gray-white matter interactions

  3. Gain in brain immunity in the oldest-old differentiates cognitively normal from demented individuals.

    Directory of Open Access Journals (Sweden)

    Pavel Katsel

    Full Text Available BACKGROUND: Recent findings suggest that Alzheimer's disease (AD neuropathological features (neuritic plaques and NFTs are not strongly associated with dementia in extreme old (over 90 years of age and compel a search for neurobiological indices of dementia in this rapidly growing segment of the elderly population. We sought to characterize transcriptional and protein profiles of dementia in the oldest-old. METHODS AND FINDINGS: Gene and protein expression changes relative to non-demented age-matched controls were assessed by two microarray platforms, qPCR and Western blot in different regions of the brains of oldest-old and younger old persons who died at mild or severe stages of dementia. Our results indicate that: i consistent with recent neuropathological findings, gene expression changes associated with cognitive impairment in oldest-old persons are distinct from those in cognitively impaired youngest-old persons; ii transcripts affected in young-old subjects with dementia participate in biological pathways related to synaptic function and neurotransmission while transcripts affected in oldest-old subjects with dementia are associated with immune/inflammatory function; iii upregulation of immune response genes in cognitively intact oldest-old subjects and their subsequent downregulation in dementia suggests a potential protective role of the brain immune-associated system against dementia in the oldest-old; iv consistent with gene expression profiles, protein expression of several selected genes associated with the inflammatory/immune system in inferior temporal cortex is significantly increased in cognitively intact oldest-old persons relative to cognitively intact young-old persons, but impaired in cognitively compromised oldest-old persons relative to cognitively intact oldest-old controls. CONCLUSIONS: These results suggest that disruption of the robust immune homeostasis that is characteristic of oldest-old individuals who avoided

  4. Effects of mechanical milling on the carbothermal reduction of oxide of WC/Co hardmetal scrap

    Science.gov (United States)

    Lee, Gil-Geun; Ha, Gook-Hyun

    2016-03-01

    The effects of mechanical milling on the carbothermal reduction of oxidized WC/Co hardmetal scrap with solid carbon were examined. Mixed powders were manufactured by milling the WC/Co hard metal scrap oxide and carbon powder in either a tumbler-ball mill or a planetary-ball mill. The milling type affected the carbothermal reduction of the oxide owing to the differing collision energies (mechanical milling energies) in the mills. The hardmetal scrap oxide powder (WO3, CoWO4) milled at high energy was more greatly reduced and at a lower temperature than that milled at lower mechanical energy. The formation of WC by the carburization reaction with solid carbon reached completion at a lower temperature after higher-energy milling than after lower-energy milling. The WC/Co composite particles synthesized by the combined oxidationmechanical milling-carbothermal reduction process were smaller when the initial powder was milled at higher mechanical energy.

  5. Microstructure and mechanical properties of WC-Ni-Al based cemented carbides developed for engineering applications

    Energy Technology Data Exchange (ETDEWEB)

    Correa, Edmilson O.; Santos, Julio N. [Universidade Federal de Itajuba, Minas Gerais (Brazil). Inst. de Engenharia Mecanica; Klein, Aloisio N. [Universidade Federal de Santa Catarina, Florianopolis (Brazil). Dept. de Engenharia de Materiais

    2011-11-15

    In this paper the influence of the Ni binder metal and Al as an additional alloying element on the microstructure and mechanical properties of WC-based cemented carbides processed by conventional powder metallurgy was studied. Microstructural examinations of the cemented carbides with 3 and 5 wt.% of Al in the binder metal indicated the presence of a very low and evenly distributed porosity as well as the presence of islands of metal binder in the microstructure. With the cemented carbide with 7 wt.% of Al in the metal binder, the presence of brittle needle-like regions was observed. The WC particles inside these regions were rounded and had a larger mean free path. Vickers hardness and flexural strength tests indicated that the cemented carbide WC-Ni - Al with addition of 5 wt.% of Al in the binder metal presented bulk hardness similar to the conventional WC-Co cemented carbides as well as superior flexure strength and fracture toughness. (orig.)

  6. Corrosion of WC-VC-Co hardmetal in neutral chloride containing media

    CSIR Research Space (South Africa)

    Machio, Christopher N

    2013-01-01

    Full Text Available by introducing more corrosion resistant elements. Nickel, and chromium especially, and recently, ruthenium have been shown to markedly improve the corrosion resistance of WC-Co-based hardmetal...

  7. Study on residual stresses of Ni-based WC coating by laser remelting based on XRD

    Science.gov (United States)

    Chen, Zhigang; Kong, Dejun; Wang, Ling; Zhu, Xiaoron; Zhao, Xiaobing

    2007-12-01

    The morphologies of Ni-based WC coating by flame spraying and laser cladding respectively were observed with scanning electric microscope (SEM), respectively, and residual stresses were measured with XRD (X-ray diffraction). At the same time, the spectra of WC coating were analyzed by XRD, and the forming mechanisms of residual stress were analyzed. Experimental results are shown that residual stresses of Ni-based WC coating by flame spraying are all tensile while those by laser cladding are compressive, chemical-physical reaction of the coating is the cause to result in material volume change, which makes residual stress into compressive from tensile; when residual stress is changed into compressive from tensile, micro-cracks on the coating surface greatly decrease, which is illustrated that the effect of residual stress on micro-crack is obvious; XRD spectra peak of WC coating is only contained Ni and W, and has no impurity and other reaction productions.

  8. The endocytosis and signaling of the γδ T cell coreceptor WC1 are regulated by a dileucine motif.

    Science.gov (United States)

    Hsu, Haoting; Baldwin, Cynthia L; Telfer, Janice C

    2015-03-01

    WC1 proteins, which are specifically expressed by bovine γδ T cells from a gene array containing 13 members, are part of the scavenger receptor cysteine-rich family. WC1 cytoplasmic domains contains multiple tyrosines, one of which is required to be phosphorylated for TCR coreceptor activity, and a dileucine endocytosis motif. Like the TCR coreceptor CD4, WC1 is endocytosed in response to PMA. Because WC1 endocytosis may play a role in the activation of γδ T cells, we examined WC1 endocytosis in the adherent cell 293T and Jurkat T cell lines using a fusion protein of extracellular CD4 and the transmembrane and cytoplasmic domain of WC1. Individual mutation of the two leucine residues of the endocytic dileucine motif in the WC1 cytoplasmic domain significantly reduced PMA-induced endocytosis in both cell types and enhanced IL-2 production stimulated by cocross-linking of CD3/TCR and CD4/WC1 in Jurkat cells, suggesting that the sustained membrane coligation of CD3/TCR with WC1 caused by a decrease in endocytosis increases T cell activation. Mutation of two serines upstream of the endocytic dileucine motif affected endocytosis only in adherent 293T cells. Although the two upstream serines were not required for WC1 endocytosis in Jurkat cells, the pan-protein kinase C inhibitor Gö6983 blocked endocytosis of CD4/WC1, and mutation of the upstream serines in WC1 inhibited IL-2 production stimulated by cocross-linking of CD3/TCR and CD4/WC1. These studies provide insights into the signaling of WC1 gene arrays that are present in most mammals and play critical roles in γδ T cell responses to bacterial pathogens.

  9. Microstructure of Ni / WC Surface Composite Layer on Gray Iron Substrate

    Institute of Scientific and Technical Information of China (English)

    YANG Guirong; SONG Wenming; MA Ying; LU Jinjun; HAO Yuan; LI Yuandong; WANG Haitang

    2011-01-01

    The surface infiltrated composite (Ni/WC) layers on gray iron substrate were fabricated through a vacuum infiltration casting technique (VICT) using Ni-based composite powder with different WC particles content as raw materials.The microstructures of surface infiltrated composite layer,the interface structures between surface composite layer and the substrate,the changes of macro-hardness with the increasing of WC content and the micro-hardness distribution are investigated.The infiltrated composite layer includes a surface composite layer and a transition layer,and the thickness of the transition layer decreases with the increasing content of WC.The thickness of transition layer with 20%WC content in the surface infiltrated composite layer was 170 μrn which was the thickest for all transition layers with different WC content.The surface composite layer was mainly composed of WC,W2C,FeB and NiB,along with Ni-Cr-Fe,Ni (Cr) solid solution,Ni (Si) solid solution and Ni (Fe) solid solution.The transition layer was composed of Ni (Cr) solid solution,Ni (Fe) solid solution,Ni (Si) solid solution,Fe (Ni) solid solution and eutectic.The surface macrohardness and micro-hardness of the infiltrated layer had been evaluated.The macro-hardness of the surface composite layer decreases with the WC content increasing,and the average macro-hardness is HRC60.The distribution of micro-hardness presents gradient change.The average micro-hardness of the infiltrated layer is about HV 1000.

  10. Review on Sintering Process of WC-Co Cemented Carbide in Metal Injection Molding Technology

    Science.gov (United States)

    Prathabrao, M.; Amin, Sri Yulis M.; Ibrahim, M. H. I.

    2017-01-01

    The objective of this paper is to give an overview on sintering process of WC-Co cemented carbides in metal injection molding technology. Metal injection molding is an advanced and promising technology in producing cemented nanostructured carbides. Cemented tungsten carbide (WC-Co) hard metal is known for its high hardness and wear resistance in various applications. Moreover, areas include fine grained materials, alternative binders, and alternative sintering techniques has been discussed in this paper.

  11. Obtaining Crack-free WC-Co Alloys by Selective Laser Melting

    Science.gov (United States)

    Khmyrov, R. S.; Safronov, V. A.; Gusarov, A. V.

    Standard hardmetals of WC-Co system are brittle and often crack at selective laser melting (SLM). The objective of this study is to estimate the range of WC/Co ratio where cracking can be avoided. Micron-sized Co powder was mixed with WC nanopowder in a ball mill to obtain uniform distribution of WC over the surface of Co particles. Continuous layers of remelted material on the surface of a hardmetal plate were obtained from this composite powder by SLM at 1.07μm wavelength. The layers have satisfactory porosity and are well bound to the substrate. The chemical composition of the layers matches the composition of the initial powder mixtures. The powder mixture with 25wt.%WC can be used for SLM to obtain materials without cracks. The powder mixture with 50wt.%WC cracks because of formation of brittle W3Co3C phase. Cracking can considerably reduce the mechanical strength, so that the use of this composition is not advised.

  12. Long-Term Stability of WC-C Peritectic Fixed Point

    Science.gov (United States)

    Khlevnoy, B. B.; Grigoryeva, I. A.

    2015-03-01

    The tungsten carbide-carbon peritectic (WC-C) melting transition is an attractive high-temperature fixed point with a temperature of . Earlier investigations showed high repeatability, small melting range, low sensitivity to impurities, and robustness of WC-C that makes it a prospective candidate for the highest fixed point of the temperature scale. This paper presents further study of the fixed point, namely the investigation of the long-term stability of the WC-C melting temperature. For this purpose, a new WC-C cell of the blackbody type was built using tungsten powder of 99.999 % purity. The stability of the cell was investigated during the cell aging for 50 h at the cell working temperature that tooks 140 melting/freezing cycles. The method of investigation was based on the comparison of the WC-C tested cell with a reference Re-C fixed-point cell that reduces an influence of the probable instability of a radiation thermometer. It was shown that after the aging period, the deviation of the WC-C cell melting temperature was with an uncertainty of.

  13. Wear behavior of Ni/WC surface-infiltrated composite coating on copper substrate

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Gui-rong; Ma, Ying; Hao, Yuan [Lanzhou University of Technology, Gansu (China). State Key Laboratory of Advanced Processing and Recycling of Nonferrous Metals; Song, Wen-ming [Lanzhou University of Technology, Gansu (China). State Key Laboratory of Advanced Processing and Recycling of Nonferrous Metals; Lanzhou Petroleum Machinery Institute, Gansu (China); Li, Jian [Wuhan Research Institute of Materials Protection (China); Lu, Jin-jun [Chinese Academy of Sciences, Lanzhou, Gansu (China). State Key Laboratory of Solid Lubrication

    2016-01-15

    Ni/WC surface-infiltrated composite coating was fabricated on copper alloy substrate through vacuum infiltration casting using Ni-based alloying powder and with different WC particle contents as raw materials. The wear behavior of Ni/WC surface-infiltrated composite coating was investigated using a block-on-ring tester at different loads and sliding speeds at room temperature. Results show that the wear rate of Ni/WC surface-infiltrated composite coating decreased to approximately one-sixth of the wear rate of the Ni-based alloy infiltrated coating. This phenomenon resulted from the supporting function of WC particles under varying loads applied on the specimen surface and the antifriction effect of the transformation layer. Wear rate was reduced by the Ni/WC-infiltrated composite coating with increasing load, especially when the load exceeded 100 N. The friction coefficient decreased with increasing sliding speed for all infiltrated coatings at any load condition. The reduction in the friction coefficient at high sliding speed was larger than that at low sliding speed with increasing load. The wear mechanism was dominated by oxidation under all experimental conditions and accompanied by adhesion and abrasion mechanisms at high load and high sliding speed.

  14. Overview of Deployed EDS Technologies

    Energy Technology Data Exchange (ETDEWEB)

    Martz, H E; Crawford, C

    2009-09-24

    The term explosive detection system (EDS) is used by the TSA to describe equipment that is certified to detect explosives in checked bags. The EDS, as certified, by the TSL must consist of device for interrogating a bag and an automated detection algorithm (ATD) for evaluating the results of the interrogation. We only consider CT as the interrogation device in this report. A schematic drawing of a CT-based EDS is shown in Figure 2. The output of the ATD is the binary decision of alarm or non-alarm. Alarms may true- or false-positives. Non-alarms may be true- or false-negatives. False positives are also denoted false alarms. The true detection means that the ATD reports an alarm when a threat is present in the scanned bag. The probability of detecting a threat given that a threat is present is denoted the probability of detection (PD). The probability of false alarm (PFA) is the case when an alarm is reported when a threat is not present in a bag. Certification in this context means passing tests for PD and PFA at the TSL. The results of the EDS include CT cross-sectional images of the bag and specifics about the alarmed objects generated by ATD. These results are presented on a display so that a person may override the decision of ATD and declare the alarm to be a non-alarm. This process is denoted clearing. Bags that are not cleared by the person are sent to a secondary inspection process. Here the bags may be opened or assessed with explosive trace detection (ETD) in order to clear the bags. Bags that are not cleared at this point are evaluated by an ordinance disposal team. The CT scanner along with ATD is denoted Level 1 screening. The process of clearing on a display is denoted Level 2 screening. Secondary inspection is denoted Level 3 screening. Vendors of the deployed EDSs supply the TSA with equipment for all three levels. Therefore, the term EDS may include the equipment provided for Levels 1, 2 and 3. A schematic diagram of an EDS and the levels of

  15. The project “understAID” – a platform that helps informal caregivers to understand and aid their demented relatives

    DEFF Research Database (Denmark)

    Skorupska, Elżbieta; Mojs, Ewa; Samborski, Włodzimierz;

    2014-01-01

    of dementia patients. The project was launched in April 2013 and is expected to end 36 months later. The project is divided into fi ve tasks concerning the fi nal aim. The aim of task 1 is the management of the project, as well as the exploitation and dissemination of gathered information. Task 2 is meant...... to defi ne the contents and solutions of the CarePlatform based on the knowledge gained from real-case studies. Demented elderlies from each country (n = 40) suffering from different degrees of dementia were evaluated by formal caregivers and dementia professionals. The aim of task 3 is the development...

  16. Ed Watson - 1940-2006

    CERN Document Server

    2006-01-01

    Ed Watson passed away suddenly on 1 August in Geneva, he was 66. He leaves his wife and two children. Ed Watson arrived at CERN in March 1973 to work on digital electronics and CAMAC systems under Bob Dobinson, after many years at Rolls Royce in Scotland. He joined the European Muon Collaboration in 1976, where he played a major role in the design, deployment and running of its data acquisition system (DAQ) with David Botterill, Bob Dobinson, and Vicky White. The CAMAC-ROMULUS system was by far the largest and most advanced of its time, and it became a defining standard for DAQ systems for years to come. Ed was deeply involved in the detailed planning of the control rooms and the experiment cabling, as well as sharing the responsibility for the CAMAC readout system. He had a real talent for trouble shooting and played a vital part in supporting the experiment throughout its lifetime. He offered great moral support to the younger members of the collaboration and helped them a great deal with their work. The...

  17. Ed Watson 1940-2006

    CERN Multimedia

    2006-01-01

    Ed Watson arrived at CERN in March 1973 to work on digital electronics and CAMAC systems under Bob Dobinson, after many years at Rolls Royce in Scotland. He joined the European Muon Collaboration in 1976, where he played a major role in the design, deployment and running of its data acquisition system (DAQ) with David Botterill, Bob Dobinson, and Vicky White. The CAMAC-ROMULUS system was by far the largest and most advanced of its time, and it became a defining standard for DAQ systems for years to come. Ed was deeply involved in the detailed planning of the control rooms and the experiment cabling, as well as sharing the responsibility for the CAMAC readout system. He had a real talent for trouble shooting and played a vital part in supporting the experiment throughout its lifetime. He offered great moral support to the younger members of the collaboration and helped them a great deal with their work. The EMC had a wonderful social life to which Ed was a major contributor - who can forget its barbecues?  In...

  18. 35CrMo steel surface by laser cladding Fe-based WC composite coating performance analysis

    Science.gov (United States)

    Zhou, Houming; Zhang, Haomin; Qin, Hengfeng

    2014-12-01

    The laser cladding technique in 35CrMo steel substrate prepared with different dosage under WC iron-based alloy cladding.Research the effects of different cladding WC addition on surface morphology, microstructure, microhardness and wear properties. The results show that 5% and 10% WC added amount of the surface quality of the cladding layer is preferably 15 % and 25 % of the volume of the WC surface of the cladding layer with varying degrees of cracks and pores, WC adding cladding layer can significantly improve the hardness. Through analysis we draw the conculation that,with 10% WC addition of iron-based alloy cladding the microhardness is 4.2 times the substrate , the relative wear resistance increased 4.1 than the substrate , enabling optimum cladding friction and wear properties.

  19. ABCB1 genotypes and haplotypes in patients with dementia and age-matched non-demented control patients

    Directory of Open Access Journals (Sweden)

    Frankfort Suzanne V

    2006-09-01

    Full Text Available Abstract Amyloid β is an in vitro substrate for P-glycoprotein (P-gp, an efflux pump at the blood brain barrier (BBB. The Multi Drug Resistance (ABCB1 gene, encoding for P-gp, is highly polymorphic and this may result in a changed function of P-gp and may possibly interfere with the pathogenesis of Alzheimer's disease. This study investigates to what extent ABCB1 Single Nucleotide Polymorphisms (SNPs; C1236T in exon 12, G2677T/A in exon 21 and C3435T in exon 26 and inferred haplotypes exist in an elderly population and if these SNPs and haplotypes differ between patients with dementia and age-matched non-demented control patients. ABCB1 genotype, allele and haplotype frequencies were neither significantly different between patients with dementia and age-matched controls, nor between subgroups of different types of dementia nor age-matched controls. This study shows ABCB1 genotype frequencies to be comparable with described younger populations. To our knowledge this is the first study on ABCB1 genotypes in dementia. ABCB1 genotypes are presently not useful as a biomarker for dementia, as they were not significantly different between demented patients and age-matched control subjects.

  20. The process of a group intervention for caregivers of demented persons living at home: conceptual framework, components, and characteristics.

    Science.gov (United States)

    Lévesque, L; Gendron, C; Vézina, J; Hébert, R; Ducharme, F; Lavoie, J-P; Gendron, M; Voyer, L; Préville, M

    2002-08-01

    Most earlier group interventions for caregivers of demented persons lacked a theoretical basis to guide the intervention process and focused on providing information and practical advice and encouraging the expression of feelings. This article presents the process of a group intervention with emphasis on its conceptual framework, components and characteristics. As caregivers are exposed to numerous daily stressful demands, the intervention's conceptual framework was derived from Lazarus and Folkman's transactional theory of stress and coping and Folkman's Coping Effectiveness Training Program. The central aim of the intervention was to improve the ability of caregivers to cope with the stressful demands at the core of caring for a demented person, rather than to focus on information and the task-oriented aspects of caring. The two components of the intervention deal with the cognitive appraisal of stressors and coping strategies, with a view to determining which strategies are most appropriate on the basis of the changeability of stressors. Three coping strategies were proposed: problem solving (problem-focused coping to deal with changeable stressors), reframing (emotion-focused coping to manage the emotional response to unchangeable stressors), and seeking social support (problem- or emotion-focused coping). The most salient characteristics of this group intervention were its intensity (15 meetings) and its focus on the caregivers' daily reality, which provided concrete reference points for the discussion of conceptual notions.

  1. The Dry Sliding Wear Behavior of HVOF-Sprayed WC: Metal Composite Coatings

    Science.gov (United States)

    Ward, Liam P.; Pilkington, Antony

    2014-09-01

    WC-based cermet coatings containing various metallic binders such as Ni, Co, and Cr are known for their superior tribological properties, particularly abrasion resistance and enhanced surface hardness. Consequently, these systems are considered as replacements for traditional hard chrome coatings in critical aircraft components such as landing gear. The purpose of this investigation was to conduct a comparative study on the dry sliding wear behavior of three WC-based cermet coatings (WC-12Ni, WC-20Cr2C3-7Ni, and WC-10Co-4Cr), when deposited on carbon steel substrates. Ball on disk wear tests were performed on the coatings using a CSEM Tribometer (pin-on-disk) with a 6-mm ruby ball at 20 N applied load, 0.2 m/s sliding velocity, and sliding distances up to 2000 m. Analysis of both the coating wear track and worn ruby ball was performed using optical microscopy and an Alphastep-250 profilometer. The results of the study revealed both wear of the ruby ball and coated disks allowed for a comparison of both the ball wear and coating wear for the systems considered. Generally, the use of Co and Cr as a binder significantly improved the sliding wear resistance of the coating compared to Ni and/or Cr2C3.

  2. Synthesis and Characterizations of Nanocrystalline WC-Co Composite Powders by a Unique Ball Milling Process

    Institute of Scientific and Technical Information of China (English)

    Jun SHEN; Jianfei SUN; Faming ZHANG

    2004-01-01

    In order to explore the high efficiency of fabricating nanocrystalline WC-Co composite powders, this paper presented a unique high energy ball milling process with variable rotation rate and repeatious circulation, by which nanocrystalline WC-10Co0.8VC-0.2Cr3C2 (wt pct) composite powders with mean grain size of 25 nm were prepared in 32 min, and the quantity of the powders for a batch was as much as 800 grams. The as-prepared powders were analyzed and characterized by chemical analysis,X-ray diffraction (XRD), transmission electron microscopy (TEM) and differential thermal analysis (DTA). The results show that high energy ball milling with variable rotation rates and repeatious circulation could be used to produce nanocrystalline WC-Co powder composites with high efficiency. The compositions of the powders meet its specifications with low impurity content. The mean grain size decreases, lattice distortion and system energy increase with increasing the milling time. The morphology of nanocrystalline WC-Co particles displays dominantly sphere shape and their particle sizes are all lower than 80nm. The eutectic temperature of the nanocrystalline WC-10Co-0.8VC-0.2Cr3C2 composites is about 1280℃.

  3. HVOF sprayed WC-CoCr coatings on aluminum: tensile and tribological properties

    Science.gov (United States)

    Koutsomichalis, A.; Vardavoulias, M.; Vaxevanidis, N.

    2017-02-01

    This paper provides a comprehensive assessment of the tensile and sliding wear behaviour of WC-10Co4Cr agglomerated and sintered powder deposited on aluminum by Hyper Velocity Oxy-Fuel (HVOF) process. Microstructural analysis (SEM) identified grains of tungsten carbide (WC) in the metal matrix of the cobalt-chromium (Co-Cr). A transformation of the WC in the W2C phase was observed and decomposition of WC in the metal matrix. The HVOF WC-Co-Cr coating was found to decrease tensile strength of the aluminum substrate. Transverse cracks were observed to initiate on the coating surface, increasing rapidly with the increase in tensile strain and stopped on the coating-substrate interface causing decohesion. Tribological properties were examined using the pin-on-disk method under various loads. The friction coefficient rose abruptly at the start-up phase and stabilized at almost the same sliding distance independently of the applied load. Both the friction coefficient and the wear volume were found to increase with increasing applied load. Study of the wear mechanisms revealed surface micro-cracking and fragmentation of flattened coating layers with subsequent gradual pull out of the carbide particles.

  4. Diamond Deposition on WC/Co Alloy with a Molybdenum Intermediate Layer

    Science.gov (United States)

    Liu, Sha; Yu, Zhi-Ming; Yi, Dan-Qing

    It is known that in the condition of chemical vapor deposition (CVD) diamond process, molybdenum is capable of forming carbide known as the "glue" which promotes growth of the CVD diamond, and aids its adhesion by (partial) relief of stresses at the interface. Furthermore, the WC grains are reaction bonded to the Mo2C phase. Therefore, molybdenum is a good candidate material for the intermediate layer between WC-Co substrates and diamond coatings. A molybdenum intermediate layer of 1-3 μm thickness was magnetron sputter-deposited on WC/Co alloy prior to the deposition of diamond coatings. Diamond films were deposited by hot filament chemical vapor deposition (HFCVD). The chemical quality, morphology, and crystal structure of the molybdenum intermediate layer and the diamond coatings were characterized by means of SEM, EDX, XRD and Raman spectroscopy. It was found that the continuous Mo intermediate layer emerged in spherical shapes and had grain sizes of 0.5-1.5 μm after 30 min sputter deposition. The diamond grain growth rate was slightly slower as compared with that of uncoated Mo layer on the WC-Co substrate. The morphologies of the diamond films on the WC-Co substrate varied with the amount of Mo and Co on the substrate. The Mo intermediate layer was effective to act as a buffer layer for both Co diffusion and diamond growth.

  5. The Synthesis of Nanostructured WC-Based Hardmetals Using Mechanical Alloying and Their Direct Consolidation

    Directory of Open Access Journals (Sweden)

    N. Al-Aqeeli

    2014-01-01

    Full Text Available Tungsten carbide- (WC- based hardmetals or cemented carbides represent an important class of materials used in a wide range of industrial applications which primarily include cutting/drilling tools and wear resistant components. The introduction and processing of nanostructured WC-based cemented carbides and their subsequent consolidation to produce dense components have been the subject of several investigations. One of the attractive means of producing this class of materials is by mechanical alloying technique. However, one of the challenging issues in obtaining the right end-product is the possible loss of the nanocrystallite sizes due to the undesirable grain growth during powder sintering step. Many research groups have engaged in multiple projects aiming at exploring the right path of consolidating the nanostructured WC-based powders without substantially loosing the attained nanostructure. The present paper highlights some key issues related to powder synthesis and sintering of WC-based nanostructured materials using mechanical alloying. The path of directly consolidating the powders using nonconventional consolidation techniques will be addressed and some light will be shed on the advantageous use of such techniques. Cobalt-bonded hardmetals will be principally covered in this work along with an additional exposure of the use of other binders in the WC-based hardmetals.

  6. AdvancED Flex 4

    CERN Document Server

    Tiwari, Shashank; Schulze, Charlie

    2010-01-01

    AdvancED Flex 4 makes advanced Flex 4 concepts and techniques easy. Ajax, RIA, Web 2.0, mashups, mobile applications, the most sophisticated web tools, and the coolest interactive web applications are all covered with practical, visually oriented recipes. * Completely updated for the new tools in Flex 4* Demonstrates how to use Flex 4 to create robust and scalable enterprise-grade Rich Internet Applications.* Teaches you to build high-performance web applications with interactivity that really engages your users.* What you'll learn Practiced beginners and intermediate users of Flex, especially

  7. Real time analysis under EDS

    Energy Technology Data Exchange (ETDEWEB)

    Schneberk, D.

    1985-07-01

    This paper describes the analysis component of the Enrichment Diagnostic System (EDS) developed for the Atomic Vapor Laser Isotope Separation Program (AVLIS) at Lawrence Livermore National Laboratory (LLNL). Four different types of analysis are performed on data acquired through EDS: (1) absorption spectroscopy on laser-generated spectral lines, (2) mass spectrometer analysis, (3) general purpose waveform analysis, and (4) separation performance calculations. The information produced from this data includes: measures of particle density and velocity, partial pressures of residual gases, and overall measures of isotope enrichment. The analysis component supports a variety of real-time modeling tasks, a means for broadcasting data to other nodes, and a great degree of flexibility for tailoring computations to the exact needs of the process. A particular data base structure and program flow is common to all types of analysis. Key elements of the analysis component are: (1) a fast access data base which can configure all types of analysis, (2) a selected set of analysis routines, (3) a general purpose data manipulation and graphics package for the results of real time analysis. Each of these components are described with an emphasis upon how each contributes to overall system capability. 3 figs.

  8. Improved Wear Resistance of Low Carbon Steel with Plasma Melt Injection of WC Particles

    Science.gov (United States)

    Liu, Aiguo; Guo, Mianhuan; Hu, Hailong

    2010-08-01

    Surface of a low carbon steel Q235 substrate was melted by a plasma torch, and tungsten carbide (WC) particles were injected into the melt pool. WC reinforced surface metal matrix composite (MMC) was synthesized. Dry sliding wear behavior of the surface MMC was studied and compared with the substrate. The results show that dry sliding wear resistance of low carbon steel can be greatly improved by plasma melt injection of WC particles. Hardness of the surface MMC is much higher than that of the substrate. The high hardness lowers the adhesion and abrasion of the surface MMC, and also the friction coefficient of it. The oxides formed in the sliding process also help to lower the friction coefficient. In this way, the dry sliding wear resistance of the surface MMC is greatly improved.

  9. Dissimilar joint characteristics of SiC and WC-Co alloy by laser brazing

    Science.gov (United States)

    Nagatsuka, K.; Sechi, Y.; Nakata, K.

    2012-08-01

    SiC and WC-Co alloys were joined by laser brazing with an active braze metal. The braze metal based on eutectic Ag-Cu alloy with additional Ti as an active element ranging from 0 to 2.8 mass% was sandwiched by the SiC block and WC-Co alloy plate. The brazing was carried out by selective laser beam irradiation on the WC-Co alloy plate. The content of Ti in the braze metal was required to exceed 0.6 mass% in order to form a brazed joint with a measurable shear strength. The shear strength increased with increasing Ti content up to 2.3 mass%Ti and decreased with a higher content.

  10. Effect of gas corrosion on the character of phase boundaries in Ni3Al / WC composite

    Directory of Open Access Journals (Sweden)

    E. Fras

    2009-04-01

    Full Text Available In view of quite specific physico-chemical and performance properties, the composite based on an intermetallic Ni3Al compoundreinforced with tungsten carbides (WC was selected for investigations. The said composite is characterised by very good mechanical and tribological properties within a wide range of temperatures, combined with good corrosion resistance. In fabrication of the Ni3Al/WC composite, a modified variant of the SHS process was applied. It is the SHSB process, i.e. the Self- Propagating High-Temperature Synthesis in Bath. The said method enables obtaining pure products of reaction, unoxidised and free from the precipitates of alien phases.The main goal of this study has been determination of the susceptibility of the Ni3Al/WC composite to gas corrosion. To examine the microstructure and chemical composition of both the composite and the scale, the metallographic and structural examinations were made,using optical and scanning microscopy.

  11. Nanotoxicity: emerging concerns regarding nanomaterial safety and occupational hard metal (WC-Co nanoparticle exposure

    Directory of Open Access Journals (Sweden)

    Armstead AL

    2016-12-01

    Full Text Available Andrea L Armstead,1,2 Bingyun Li1–3 1Department of Orthopaedics, School of Medicine, 2School of Pharmacy, West Virginia University, 3Mary Babb Randolph Cancer Center, Morgantown, WV, USA Abstract: As the number of commercial and consumer products containing engineered nanomaterials (ENMs continually rises, the increased use and production of these ENMs presents an important toxicological concern. Although ENMs offer a number of advantages over traditional materials, their extremely small size and associated characteristics may also greatly enhance their toxic potentials. ENM exposure can occur in various consumer and industrial settings through inhalation, ingestion, or dermal routes. Although the importance of accurate ENM characterization, effective dosage metrics, and selection of appropriate cell or animal-based models are universally agreed upon as important factors in ENM research, at present, there is no “standardized” approach used to assess ENM toxicity in the research community. Of particular interest is occupational exposure to tungsten carbide cobalt (WC-Co “dusts,” composed of nano- and micro-sized particles, in hard metal manufacturing facilities and mining and drilling industries. Inhalation of WC-Co dust is known to cause “hard metal lung disease” and an increased risk of lung cancer; however, the mechanisms underlying WC-Co toxicity, the inflammatory disease state and progression to cancer are poorly understood. Herein, a discussion of ENM toxicity is followed by a review of the known literature regarding the effects of WC-Co particle exposure. The risk of WC-Co exposure in occupational settings and the updates of in vitro and in vivo studies of both micro- and nano-WC-Co particles are discussed. Keywords: engineered nanomaterial, occupational exposure, lung disease, cancer, toxicity, particle

  12. WC-Co硬质合金微观结构的参数化模型%Parametric Modeling of Microstructure of WC-Co Cemented Carbides

    Institute of Scientific and Technical Information of China (English)

    王东; 赵军; 李安海; 王泽明

    2013-01-01

    为实现WC-Co硬质合金的性能预报和微观结构的优化,提出了一种基于“随机法”构建材料二维微观结构模型的方法,该模型包含WC-Co硬质合金微观结构中WC晶粒的平均粒径、形心位置、取向角、长径和短径尺寸以及Co相体积分数等基本参数.采用C++,Matlab和Python语言汇合编程,得到可以直接导人有限元分析软件的模型.结果表明:构建的模型反映了真实的微观结构特征,实现了微观结构的参数化建模.模型的设计参数与实际参数比较吻合,证明了建模方法的可行性和模型的可靠性.%In order to realize the property prediction and microstructure optimization of WC-Co cemented carbides, a model based on "random method", which referred to the construction of two-dimensional microstructure model, was established. Some basic parameters of the microstructure of WC-Co, including average grain diameter, major axis and minor axis, centroid, orientation angle and the Co volume fraction, were considered in the model. C+ + , Matlab, Python are mixed for programming. The model can be obtained in the mixed program, which can be directly applied in the finite element software. The results show that the actual microstructure characteristics of material can be reconstructed, and the parametric model of microstructure is realized. The design parameters agree well with the actual ones, the feasibility of the method and the reliability of the model are proved.

  13. Exploring the potential role of tungsten carbide cobalt (WC-Co) nanoparticle internalization in observed toxicity toward lung epithelial cells in vitro

    Energy Technology Data Exchange (ETDEWEB)

    Armstead, Andrea L. [Biomaterials, Bioengineering and Nanotechnology Laboratory, Department of Orthopaedics, School of Medicine, West Virginia University, Morgantown, WV 26506 (United States); Pharmaceutical and Pharmacological Sciences Graduate Program, School of Pharmacy, West Virginia University, Morgantown, WV 26506 (United States); Arena, Christopher B. [Biomaterials, Bioengineering and Nanotechnology Laboratory, Department of Orthopaedics, School of Medicine, West Virginia University, Morgantown, WV 26506 (United States); E.J. Van Liere Research Program, School of Medicine, West Virginia University, Morgantown, WV 26506 (United States); Li, Bingyun, E-mail: bili@hsc.wvu.edu [Biomaterials, Bioengineering and Nanotechnology Laboratory, Department of Orthopaedics, School of Medicine, West Virginia University, Morgantown, WV 26506 (United States); Pharmaceutical and Pharmacological Sciences Graduate Program, School of Pharmacy, West Virginia University, Morgantown, WV 26506 (United States); E.J. Van Liere Research Program, School of Medicine, West Virginia University, Morgantown, WV 26506 (United States); Mary Babb Randolph Cancer Center, Morgantown, WV 26506 (United States)

    2014-07-01

    Tungsten carbide cobalt (WC-Co) has been recognized as a workplace inhalation hazard in the manufacturing, mining and drilling industries by the National Institute of Occupational Safety and Health. Exposure to WC-Co is known to cause “hard metal lung disease” but the relationship between exposure, toxicity and development of disease remain poorly understood. To better understand this relationship, the present study examined the role of WC-Co particle size and internalization on toxicity using lung epithelial cells. We demonstrated that nano- and micro-WC-Co particles exerted toxicity in a dose- and time-dependent manner and that nano-WC-Co particles caused significantly greater toxicity at lower concentrations and shorter exposure times compared to micro-WC-Co particles. WC-Co particles in the nano-size range (not micron-sized) were internalized by lung epithelial cells, which suggested that internalization may play a key role in the enhanced toxicity of nano-WC-Co particles over micro-WC-Co particles. Further exploration of the internalization process indicated that there may be multiple mechanisms involved in WC-Co internalization such as actin and microtubule based cytoskeletal rearrangements. These findings support our hypothesis that WC-Co particle internalization contributes to cellular toxicity and suggest that therapeutic treatments inhibiting particle internalization may serve as prophylactic approaches for those at risk of WC-Co particle exposure. - Highlights: • Hard metal (WC-Co) particle toxicity was established in lung epithelial cells. • Nano-WC-Co particles caused greater toxicity than micro-WC-Co particles. • Nano- and micro-WC-Co particles were capable of inducing cellular apoptosis. • Nano-WC-Co particles were internalized by lung epithelial cells. • WC-Co particle internalization was mediated by actin dynamics.

  14. Study on GNi-WC25 Coating by High Frequency Induction Cladding

    Institute of Scientific and Technical Information of China (English)

    张增志; 韩桂泉; 付跃文; 沈立山

    2002-01-01

    Process and mechanism of high frequency were studied in this paper by means of cold-attachment for the preparation of Gni-WC25 coating . The resu lts show its special distribution law of eddy current while the magnetic transition temperature and electric-resistivity of the coating have been measured .Wear-resistance of the high-frequency induction coating has an advantage over those of laser cladding coating and oxygen-acetylene spraying-fusing coating . Moreover , the Gni-WC25 coating by high-frequency induction claddi ng has smooth surface and even microstructure.

  15. PREPARATION OF WC-Co POWDER BY DIRECT REDUCTION AND CARBONIZATION

    Institute of Scientific and Technical Information of China (English)

    Zhonglai Yi; Gangqin Shao; Xinglong Duan; Peng Sun; Xiaoliang Shi; Zhen Xiong; Jingkun Guo

    2005-01-01

    A new approach to produce superfine WC-Co powder by direct reduction and carbonization is proposed.Water-soluble salts containing W and Co were used as raw materials. Tungsten and cobalt oxide powder (CoWO4/WO3)was first formed by a spray-pyrolysis technique, which was then mixed with carbon black and converted to WC-Co composite powder at 950℃ for 4 h in N2 atmosphere. The resulting powder has a particle size of 100-300 nm.

  16. Finite element analysis of WC-Al2O3 composites

    Science.gov (United States)

    Patel, Satyanarayan; Vaish, Rahul

    2014-02-01

    Object oriented finite element analysis (OOF2) is used to estimate the thermal and mechanical properties of WC-Al2O3 composites. In the present work, five compositions of 10%, 20%, 30%, 40% and 50% Al2O3 (by volume) are studied. Young's modulus, thermal conductivity and thermal expansion coefficient are estimated using OOF2 and compared with other known analytical methods. Stress and strain contours are plotted to study the thermal and mechanical behavior of composites. It is found that the stresses are largely concentrated at the interfaces of the WC-Al2O3 phases.

  17. Determining element abundances of [WC]-type Central Stars for probing stellar evolution and nucleosynthesis

    CERN Document Server

    Todt, H; Hamann, W -R; Gräfener, G

    2007-01-01

    [WC]-type CSPNs are hydrogen-deficient Central Stars of Planetary Nebulae showing strong stellar winds and a carbon-rich chemistry. We have analyzed new high-resolution spectra of [WC]-type CSPNs with the Potsdam Wolf-Rayet (PoWR) non-LTE expanding atmosphere models, using upgraded model atoms and atomic data. Previous analyses are repeated on the basis of the current models which account for iron-line blanketing. We especially focus on determining the chemical composition, including some trace elements like nitrogen which are of key importance for understanding the evolutionary origin of the hydrogen-deficient Central Stars.

  18. Benzotriazole (BTA), A Promising Corrosion Inhibitor for WC-Co Hardmetal

    Energy Technology Data Exchange (ETDEWEB)

    Schnyder, B.; Stoessel-Sittig, C.; Koetz, R.; Hochstrasser-Kurz, S. [ETH Zuerich (Switzerland); Virtanen, S. [ETH Zuerich (Switzerland); Jaeggi, Ch. [University of Bern (Switzerland); Eichenberger, N. [University of Bern (Switzerland); Szoecs, E. [University of Bern (Switzerland); Siegenthaler, H. [University of Bern (Switzerland); Ziegler, P. [AGIE SA (Switzerland); Beltrami, I. [AGIE SA (Switzerland)

    2004-03-01

    Wire Electro-Discharge Machining (W-EDM) of tungsten carbide with Co-binder may lead to corrosion and discolouration at the surface. The corrosion behaviour of WC-Co based hardmetal was investigated in different aqueous solutions (acidic, neutral, and alkaline solutions). At open-circuit potential WC-Co based hardmetals show rather high dissolution rates in all types of electrolyte. An efficient corrosion inhibitor (benzotriazole, C{sub 6}H{sub 5}N{sub 3}) could be found for a borate buffer solution, pH = 8.4. (author)

  19. Interface behavior study of WC92-Co8 coating produced by electrospark deposition

    Institute of Scientific and Technical Information of China (English)

    汪瑞军; 钱乙余; 刘军

    2004-01-01

    ESD (electrospark deposition) is a promising process to produce hard and wear-resisting coatings on metallic substrates. In this paper microstructure and interfacial characteristics of the WC92-Co8 coated on titanium and carbon steel are presented. A metallurgical bonding between the coating and substrate is obtained. The Ti element was found to distribute in WC92-Co8 at the metal pool, as well as the interface by diffusion. Some new phases were produced in the coating layer due to the chemical reaction during the ESD process. Experimental observation and thermodynamic analysis were utilized to study the mechanism of ESD.

  20. Research on Ultrafine WC-10Co Cemented Carbide with High Properties

    Institute of Scientific and Technical Information of China (English)

    SHI Xiaoliang; YANG Hua; SHAO Gangqin; DUAN Xinglong; XIONG Zhen; ZHANG Weifeng

    2006-01-01

    WC- 10Co nanocomposite powder produced by spray pyrolysis-continuous reduction and carbonization technology was used, and the vacuum sintering plus sinterhip process was adopted to prepare ultrafine WCCo cemented carbide. The microstructure, grain size, porosity, density, Rockwell A hardness ( HRA ), transverse rupture strength (TRS), saturated magnetization and coercivity force were studied. The experimental results show that average grain size of the sample prepared by vacuum sintering plus sinterhip technology was about 420 nm, transverse rupture strength was more than 3460 MPa, and Rockwell A hardness of sintered specimen was more than 92.5. Ultrafine WC- 10Co cemented carbide with high strength and high hardness is obtained.

  1. 高功率半导体激光熔覆絮状WC-Ni基超硬复合材料%High Power Diode Laser Cladding Aggregate Tungsten Carbide-Ni Based Superhard Composites

    Institute of Scientific and Technical Information of China (English)

    杨胶溪; 王智勇; 左铁钏

    2009-01-01

    高功率半导体激光器(HPDL)是新型先进装备,且体积小、电光转换效率高,在材料制备和加工方面具有良好的发展前景.使用3 kW高功率半导体激光设备,采用同步送粉的方式,在304不锈钢基体上制备絮状WC-Ni基超硬复合材料,获得了与基体冶金结合且无气孔和裂纹等缺陷的熔覆层.使用扫描电子显微镜(SEM)、能谱仪(EDS)和X射线衍射(XRD)对激光熔覆层进行组织、成分及物相表征.研究结果表明,采用半导体激光进行熔覆可获得WC较高质量分数(60%)且稀释率很低的WC-Ni超硬复合材料.激光熔覆WC-Ni基超硬复合材料的组织主要是γ-Ni,WC,W_2C,Ni_3B,CrB_2等物相组成.激光熔覆层的硬度不均匀,其平均值为HV 1100,远高于基体硬度HV 350,过渡区处硬度呈很窄的梯度分布.

  2. Semi-empirical relationship between the hardness, grain size and mean free path of WC-Co

    CSIR Research Space (South Africa)

    Makhele-Lekala, L

    2001-01-01

    Full Text Available The Vickers hardness of several well-characterized grades of WC-Co (23 in total) was measured. The mean grain size of these samples ranged from 0.6 to 5.0 mums and the cobalt content from 6 to 50 wt%. An empirical formula between hardness of WC...

  3. Wear behavior of SiC, Cr{sub 3}C{sub 2} and WC doped alumina

    Energy Technology Data Exchange (ETDEWEB)

    Mindivan, H.; Cimenoglu, H.; Kayali, E.S. [Istanbul Technical Univ., Dept. of Metallurgy and Materials Engineering, Istanbul (Turkey); Bakan, H.I. [Tubitak, MAM, Gebze-Kocaeli (Turkey)

    2004-07-01

    In this study, the wear behavior of the pure and carbide (SiC, Cr{sub 3}C{sub 2}, and WC) doped alumina was investigated. Carbide doping increased the hardness and improved the wear resistance, significantly. WC doped alumina exhibited the highest hardness and wear resistance. (orig.)

  4. The Effect of Processing Parameters on the Performance of Spark Plasma Sintered cBN-WC-Co Composites

    Science.gov (United States)

    Mao, Cong; Zhang, Mingjun; Zhang, Jian; Tang, Kun; Gan, Hangyu; Zhang, Gaofeng

    2015-12-01

    Cubic boron nitride (cBN) particles were mixed into superfine tungsten carbide (WC), and then cBN-WC-cobalt (Co) composites were prepared using spark plasma sintering method. The influence of the processing parameters on the microstructures and the mechanical properties of the cBN-WC-Co composites were investigated. The results indicated that the cBN particles arranged uniformly and had an excellent adhesion with WC matrix. There was no evidence of phase transformation from cBN to hBN. With the increasing of the sintering temperature, the liquid-phase Co was increased and entered the micro-pores between WC and cBN particles easily. Correspondingly, the density, the flexural strength, and the hardness of the cBN-WC-Co composites also increased. With the further increasing of the sintering temperature, WC grains grew leading to the reduction of the hardness. Therefore, the hardness of the samples increased to a maximum value of 2978 HV at 1250 °C, and then decreased with the sintering temperature. The experimental results also showed that the density, the flexural strength, and the hardness of cBN-WC-Co composites increased with the holding time, whereas the hardness presented a decreasing tendency when the holding time exceeded 7 min.

  5. Impaired mitochondrial energy production and ABC transporter function-A crucial interconnection in dementing proteopathies of the brain.

    Science.gov (United States)

    Pahnke, Jens; Fröhlich, Christina; Krohn, Markus; Schumacher, Toni; Paarmann, Kristin

    2013-10-01

    Ageing is the main risk factor for the development of dementing neurodegenerative diseases (NDs) and it is accompanied by the accumulation of variations in mitochondrial DNA. The resulting tissue-specific alterations in ATP production and availability cause deteriorations of cerebral clearance mechanisms that are important for the removal of toxic peptides and its aggregates. ABC transporters were shown to be the most important exporter superfamily for toxic peptides, e.g. β-amyloid and α-synuclein. Their activity is highly dependent on the availability of ATP and forms a directed energy-exporter network, linking decreased mitochondrial function with highly impaired ABC transporter activity and disease progression. In this paper, we describe a network based on interactions between ageing, energy metabolism, regeneration, accumulation of toxic peptides and the development of proteopathies of the brain with a focus on Alzheimer's disease (AD). Additionally, we provide new experimental evidence for interactions within this network in regenerative processes in AD.

  6. Plasma levels of nitric oxide related amino acids in demented subjects with Down syndrome are related to neopterin concentrations.

    Science.gov (United States)

    Coppus, A M W; Fekkes, D; Verhoeven, W M A; Tuinier, S; van Duijn, C M

    2010-03-01

    Subjects with Down syndrome (DS) have abnormalities in virtually all aspects of the immune system and almost all will be affected with Alzheimer's disease (AD). It is thought that nitric oxide (NO) is involved in the pathophysiology of AD. In the present study, including a total of 401 elderly DS subjects, the spectrum of plasma amino acids and neopterin was investigated and related to development of AD. Concentrations of nearly all amino acids in DS subjects differed significantly from those of healthy controls. Neopterin was increased in DS subjects, especially in dementia. The production of NO as reflected by an increased citrulline/arginine ratio (Cit/Arg ratio) was enhanced during development of clinical dementia. Neopterin concentrations correlated to the Cit/Arg ratio only in the group of prevalent demented subjects (rho = 0.48, P = 0.006). The results of this study are suggestive for an increase in oxidative processes in DS subjects with AD.

  7. Alzheimer's disease and non-demented high pathology control nonagenarians: comparing and contrasting the biochemistry of cognitively successful aging.

    Directory of Open Access Journals (Sweden)

    Chera L Maarouf

    Full Text Available The amyloid cascade hypothesis provides an economical mechanistic explanation for Alzheimer's disease (AD dementia and correlated neuropathology. However, some nonagenarian individuals (high pathology controls, HPC remain cognitively intact while enduring high amyloid plaque loads for decades. If amyloid accumulation is the prime instigator of neurotoxicity and dementia, specific protective mechanisms must enable these HPC to evade cognitive decline. We evaluated the neuropathological and biochemical differences existing between non-demented (ND-HPC and an age-matched cohort with AD dementia. The ND-HPC selected for our study were clinically assessed as ND and possessed high amyloid plaque burdens. ELISA and Western blot analyses were used to quantify a group of proteins related to APP/Aβ/tau metabolism and other neurotrophic and inflammation-related molecules that have been found to be altered in neurodegenerative disorders and are pivotal to brain homeostasis and mental health. The molecules assumed to be critical in AD dementia, such as soluble or insoluble Aβ40, Aβ42 and tau were quantified by ELISA. Interestingly, only Aβ42 demonstrated a significant increase in ND-HPC when compared to the AD group. The vascular amyloid load which was not used in the selection of cases, was on the average almost 2-fold greater in AD than the ND-HPC, suggesting that a higher degree of microvascular dysfunction and perfusion compromise was present in the demented cohort. Neurofibrillary tangles were less frequent in the frontal cortices of ND-HPC. Biochemical findings included elevated vascular endothelial growth factor, apolipoprotein E and the neuroprotective factor S100B in ND-HPC, while anti-angiogenic pigment epithelium derived factor levels were lower. The lack of clear Aβ-related pathological/biochemical demarcation between AD and ND-HPC suggests that in addition to amyloid plaques other factors, such as neurofibrillary tangle density and vascular

  8. Effect of back feeding angle on the structure of WC particles reinforced Ni-based coating by plasma spray welding%后送粉角度对等离子喷焊WC颗粒增强Ni基涂层组织的影响

    Institute of Scientific and Technical Information of China (English)

    李连颖; 杜晓东; 宋自力; 叶诚

    2011-01-01

    The WC reinforced Ni - based alloy composite coatings were sprayed on the surface of 45 steel by back feeding equipment of plasma spray welding. Scanning electron microscopy (SEM) , X-ray diffraction (XRD) and energy diffraction spectrum (EDS) were used to examine the microstructure and composition of the coatings. The results show that the WC particles are well-distributed in the matrix when back feeding at an angle of 30°. Around the WC particles, there are clavate microstructures. The surface microstructure of the coatings consists of WC, W2C, Fe7C3, Cr7C3 and 7- (Fe, Ni) solid solution. The hardness increases gradually from matrix to the surface of coatings. As back feeding at an angle of 90°, the WC particles are gathered at the bottom of coatings, and there are herringbone and clavate microstructures around the WC particles. The surface microstructure of the coatings consists of Cr23C6, Ni3Si, CrSi2, Fe3B, Fe7C3. From matrix to the surface of coatings, the hardness increases at the beginning and then decreases.%采用等离子喷焊技术,利用后送粉装置从不同角度在45钢表面制作WC颗粒增强镍基合金复合涂层,借助扫描电子显微镜(SEM)、X射线衍射仪(XRD)和能谱仪(EDS)分别对涂层组织结构及成分进行分析.结果表明:焊枪倾斜30°角送粉时,WC颗粒均匀的分布于涂层基体上,WC周围有明显的棒状组织,涂层表面物相主要由WC,W2C,Fe7C3,Cr7C3和γ-(Fe,Ni)固溶体等组成,由基体到涂层表面硬度呈上升趋势;焊枪垂直送粉时,WC颗粒发生了沉底现象,WC周围有明显的鱼骨状组织和棒状组织,涂层表面物相主要由Cr23C6,Ni3Si,CrSi2,Fe3B,Fe7C3等组成,由基体到涂层表面硬度先呈上升趋势,上升到一定值后又呈下降趋势.

  9. Getting the Right Wheelchair for Travel: A WC19-Compliant Wheelchair

    Science.gov (United States)

    Manary, Miriam A.; Hobson, Douglas A.; Schneider, Lawrence W.

    2007-01-01

    Children and adults who must remain seated in their wheelchairs while traveling are often at a disadvantage in terms of crash safety. The new voluntary wheelchair industry standard WC19 (short for Section 19 of the ANSI/RESNA wheelchair standards) works to close the safety gap by providing design and performance criteria and test methods to assess…

  10. Low and high temperature hardness of WC-6 wt%Co alloys

    CSIR Research Space (South Africa)

    Milman, YV

    1997-01-01

    Full Text Available The paper reports hardness measurements on WC-6 wt%Co of three different grain sizes in the temperature range from -196 to 900 degrees C. Coarser grades have been found to soften with increasing temperature at a higher rate than finer grades. It has...

  11. Study of Selected Properties of Thermally Sprayed Coatings Containing WC and WB Hard Particles

    Directory of Open Access Journals (Sweden)

    Brezinová Janette

    2016-12-01

    Full Text Available The paper presents results of research of the essential characteristics of two kinds of advanced coatings applied by HVOF technology. One studied coating: WB-WC-Co (60-30-10% contains two types of hard particles (WC and WB, the second coating is eco-friendly alternative to the previously used WC-based coatings, called “green carbides” with the composition WC-FeCrAl (85-15%. In green carbides coating the heavy metals (Co, Ni, NiCr forming the binding matrix in conventional wear-resistant coatings are replaced by more environmentally friendly matrix based on FeCrAl alloy. On the coatings was carried out: metallographic analysis, measurement of thickness, micro-hardness, adhesion, resistance to thermal cyclic loading and adhesive wear resistance (pin-on-disk test. One thermal cycle consisted of heating the coatings to 600°C, dwell for 10 minutes, and subsequently cooling on the still air. The number of thermal cycles: 10. The base material was stainless steel AISI 316L, pretreatment prior to application of the coating: blasting with white corundum, application device JP-5000.

  12. Influence of temperature, grain size and cobalt content on the hardness of WC-Co alloys

    CSIR Research Space (South Africa)

    Milman, YV

    1999-01-01

    Full Text Available The Vickers hardness of WC-Co alloys has been measured at temperatures ranging from -196 to 900 degrees C. The cobalt content of the alloys ranged from 10 to 24 vol% and the grain size from 0.5 to 2.3 um. It was found that, at all cobalt contents...

  13. New results on the relationship between hardness and fracture toughness of WC-Co hardmetal

    CSIR Research Space (South Africa)

    O'Quigley, DGF

    1996-05-01

    Full Text Available Two sets of WC-Co grades were produced, with cobalt content ranging from 3 to 50 wt.%. The mean grain size of the two sets was 2.2 and 6 mu m respectively. The two sets of grades were used to investigate the relationship between hardness...

  14. Fundamentals of grinding : surface conditions of ground WC-Co systems

    NARCIS (Netherlands)

    Hegeman, JBJW; De Hosson, JTM; Shulepov, SY; Lousberg, N; de With, G; Brebbia, CA; Kenny, JM

    1999-01-01

    This paper concentrates on the fundamentals of grinding of inorganic materials. A statistical grinding model was developed based on the topography of the grinding wheel. The results of the model are compared with the results of grinding experiments on WC-Co hardmetals. The calculated profiles and me

  15. Microstructure characterization of laser melt injected WC particles in Ti-6Al-4V

    NARCIS (Netherlands)

    Vreeling, JA; Ocelik, [No Value; De Hosson, JTM; Brebbia, CA

    2001-01-01

    The Laser Melt Injection (LMI) process is explored to create a protective Metal Matrix Composite (MMC) layer consisting of 80 mum sized WC particles embedded in the top layer of a Ti-6Al-4V alloy. In particular the influences of the main process parameters on the laser track dimensions and

  16. The Effect of Binarity and Metallicity in the Spectra of WC and WO Stars

    Directory of Open Access Journals (Sweden)

    L. Norci

    2002-01-01

    Full Text Available Se presenta el estudio estadístico de la intensidad (W, la relación y el ancho de algunas bandas de emisión de estrellas WC y WO, basado en un vasto conjunto de datos espectróscopicos. Se han obtenido valores medianos para cada tipo espectral. Se evidencia que en las estrellasWO yWC4 de la Galaxia, W(C IV 581 nm resulta ser menor que en estrellas extragalácticas. A su vez, el valor de W(O V 559 nm aumenta regularmente deWCL aWCE yWO, en las estrellas galácticas como en las extragalácticas. Suponemos que la variación de la estructura del viento estelar y de la metalicidad ambiental podrán ser la causa de las anomalías. El perfil de la banda a 465 nm evidencia, asimismo, que He II 468 nm es un componente importante en las clases WCE y WO. Se comenta también sobre las abundancias de carbono y el estado evolutivo de las estrellas WC y WO. De igual manera, se estima la relación de las intensidades del continuo OB/WR en estrellas binarias.

  17. Laser surface alloying of aluminium with WC+Co+NiCr for improved wear resistance

    CSIR Research Space (South Africa)

    Nath, S

    2012-03-01

    Full Text Available In the present study, laser surfac ealloying of aluminium with WC + Co + NiCr (in the ratio of 70:15:15) has been conducted using a 5 kW continuous wave (CW) Nd:YAG laser (at a beam diameter of 0.003 m), with the output power ranging from 3 to 3.5 k...

  18. Laser surface alloying of aluminium with WC+Co+NiCr for improved wear resistance

    CSIR Research Space (South Africa)

    Nath, S

    2012-03-01

    Full Text Available In the present study, laser surface alloying of aluminium with WC + Co + NiCr (in the ratio of 70:15:15) has been conducted using a 5 kW continuous wave (CW) Nd:YAG laser (at a beam diameter of 0.003 m), with the output power ranging from 3 to 3.5 k...

  19. WC@meso-Pt core-shell nanostructures for fuel cells.

    Science.gov (United States)

    Chen, Zhao-Yang; Ma, Chun-An; Chu, You-Qun; Jin, Jia-Mei; Lin, Xiao; Hardacre, Christopher; Lin, Wen-Feng

    2013-12-25

    We developed a facile method to synthesize core-shell WC@meso-Pt nanocatalysts by carburizing ammonium tungstate and copper nitrate via gas-solid reactions, followed by a Pt replacement reaction. The mesoporous nanocomposite displays higher activity and stability towards methanol electrooxidation than commercial Pt/C catalysts.

  20. Data of evolutionary structure change: 1B4WC-2NOTA [Confc[Archive

    Lifescience Database Archive (English)

    Full Text Available 1B4WC-2NOTA 1B4W 2NOT C A HLLQFRKMIKKMTG--KEPVVSYAFYGCYCGSGGRGKPK...03 2NOT A 2NOTA...y> -17.684999465942383 tion> -0.7129999995231628 -0.03400000184774399 -0.04600000008940697 0.9980000257492065 ...el> 1 2NOT A 2NOTA

  1. Neurospora WC-1 recruits SWI/SNF to remodel frequency and initiate a circadian cycle.

    Science.gov (United States)

    Wang, Bin; Kettenbach, Arminja N; Gerber, Scott A; Loros, Jennifer J; Dunlap, Jay C

    2014-09-01

    In the negative feedback loop comprising the Neurospora circadian oscillator, the White Collar Complex (WCC) formed from White Collar-1 (WC-1) and White Collar-2 (WC-2) drives transcription of the circadian pacemaker gene frequency (frq). Although FRQ-dependent repression of WCC has been extensively studied, the mechanism by which the WCC initiates a circadian cycle remains elusive. Structure/function analysis of WC-1 eliminated domains previously thought to transactivate frq expression but instead identified amino acids 100-200 as essential for frq circadian expression. A proteomics-based search for coactivators with WCC uncovered the SWI/SNF (SWItch/Sucrose NonFermentable) complex: SWI/SNF interacts with WCC in vivo and in vitro, binds to the Clock box in the frq promoter, and is required both for circadian remodeling of nucleosomes at frq and for rhythmic frq expression; interestingly, SWI/SNF is not required for light-induced frq expression. These data suggest a model in which WC-1 recruits SWI/SNF to remodel and loop chromatin at frq, thereby activating frq expression to initiate the circadian cycle.

  2. PREPARING NANO-CRYSTALLINE La DOPED WC/Co POWDER BY HIGH ENERGY BALL MILLING

    Institute of Scientific and Technical Information of China (English)

    S. Liu; D.Q. Yi; Y.X. Li; D. Zou

    2002-01-01

    The La doped WC/Co powder was prepared by high energy ball milling. The changesof crystal structure, micrograph and defect of the powder were investigated by means ofXRD (X-ray diffraction), SEM (scanning electron microscope) and DTA (differentialthermal analysis). The results show that adding trace La element into carbides iseffective to minish the grain size of WC/Co powder. The La doped carbides powderwith grain size of 30nm can be obtained after 1Oh ball milling. The XRD peak of Cophase disappeared after 20h ball milling, which indicated solid solution (or secondarysolid solution) of Co phase in WC phase. The La doped powder with grain size of1Ohm is obtained after 30h ball milling. A peak of heat release at the temperatureof 470℃ was emerged in DTA curve within the range of heating temperature, whichshowed that the crystal structure relaxation of the powder appeared in the process ofhigh energy ball milling. After consolidated the La doped WC/Co alloy by high energyball milling exhibits ultra-fine grain Sizes and better mechanical properties.

  3. Effect of C and milling parameters on the synthesis of WC powders by mechanical alloying

    CSIR Research Space (South Africa)

    Bolokang, S

    2009-01-01

    Full Text Available In the current study, the amount of carbon and the effects of milling parameters in production of tungsten-carbide (WC) powder were evaluated. Mechanical alloying (MA) of elemental W and C powders at different carbon-rich and carbon...

  4. Resistance of cavitation erosion of multimodal WC-12Co coatings sprayed by HVOF%超音速火焰喷涂制备多峰WC-12Co涂层的抗汽蚀性能

    Institute of Scientific and Technical Information of China (English)

    丁彰雄; 陈伟; 王群

    2011-01-01

    Conventional,submicron and multimodal WC-12Co cermet coatings were deposited by high velocity oxy-fuel (HVOF).The microhardness and microstructure of the coatings were compared,and the resistance of the coatings to cavitation erosion was studied by ultrasonic vibration cavitation equipment.Cavitation pits and craters were observed by SEM and cavitation mechanisms were explored.The results show that the microstructures of submicron and multimodal WC-12Co coatings prepared by HVOF are dense with little porosity,and their microhardness values are obviously higher than that of the conventional WC-12Co coating.The average microhardness of multimodal WC-12Co coating reaches nearly HV1500,whieh is much higher than that of the conventional one.As well,it is found that the multimodal WC-12Co coating exhibits the best cavitation erosion resistance among the three coatings,the erosion rate is approximately 40% that of the conventional coating,and the cavitation erosion resistance of multimodal WC-12Co coating is enhanced by above 150% in comparison with the conventional coating.%采用超音速火焰喷涂技术制备常规、亚微米及多峰3种WC- 12Co金属陶瓷涂层,比较分析涂层的显微硬度及显微组织.采用超声振动汽蚀装置研究3种涂层的抗汽蚀性能,并采用扫描电镜观察涂层表面的汽蚀坑,探讨不同涂层的汽蚀机理.研究表明:采用超音速火焰喷涂制备的亚微米及多峰WC- 12Co涂层结构致密、孔隙率低,其显微硬度明显高于常规的WC- 12Co涂层.多峰WC- 12Co涂层的平均显微硬度接近HV 1500,远高于常规的WC- 12Co涂层.在3种涂层中,多峰WC- 12Co涂层表现出最优良的抗汽蚀性能,涂层的汽蚀率大约为常规涂层的40%;与常规涂层相比,多峰WC-12Co涂层的抗汽蚀性能提高150%以上.

  5. Wetting of WC by a Zr-base metallic glass-forming alloy

    Energy Technology Data Exchange (ETDEWEB)

    Shen, Ping, E-mail: shenping@jlu.edu.cn [Key Laboratory of Automobile Materials (Ministry of Education), Department of Materials Science and Engineering, Jilin University, Changchun 130025 (China); Zheng, Xiao-Hong [Key Laboratory of Automobile Materials (Ministry of Education), Department of Materials Science and Engineering, Jilin University, Changchun 130025 (China); Liu, Hui-Jie [State Key Laboratory of Advanced Welding and Joining, Harbin Institute of Technology, Harbin 150001 (China); Jiang, Qi-Chuan [Key Laboratory of Automobile Materials (Ministry of Education), Department of Materials Science and Engineering, Jilin University, Changchun 130025 (China)

    2013-05-15

    Wetting of hot-pressed polycrystalline WC substrates by a Zr{sub 55}Cu{sub 30}Al{sub 10}Ni{sub 5} bulk metallic glass (BMG)-forming alloy was investigated at 1133–1253 K in a high vacuum using a modified sessile drop method. The alloy melt spread rapidly on the WC surface, reaching no more than 30° within 3 s, and then slowly (at T < 1213 K) or even remained steady (at T ≥ 1213 K) in the subsequent isothermal dwelling stage. The final equilibrium contact angles were between 11° and 20°, slightly increasing with rising temperature and thus presenting an appreciably anomalous temperature-dependent behavior. The reaction between WC and the Zr-base melt was moderate, slightly enhancing with increasing temperature, and yielded W, ZrC and W{sub 5}Zr{sub 3} at the interface. The wetting, in principle, was driven by the formation of a precursor film in front of the triple line as a result of the adsorption of active atoms (primarily Zr) rather than by the interfacial reaction. From the viewpoint of the wettability and reactivity, WC is a good reinforcement for the preparation of the Zr-base BMG matrix composites. - Highlights: ► WC shows good wettability and moderate reactivity with the Zr{sub 55}Cu{sub 30}Al{sub 10}Ni{sub 5} melt. ► The final wettability exhibits slightly anomalous dependence on temperature. ► The interfacial reaction yields ZrC, W and W{sub 5}Zr{sub 3} phases. ► The primary driving force for the wetting is the formation of the precursor film in front of the triple line.

  6. Liquid Phase Sintering of (Ti,ZrC with WC-Co

    Directory of Open Access Journals (Sweden)

    Taoran Ma

    2017-01-01

    Full Text Available (Ti,ZrC powder was sintered with WC-Co following an industrial process, including an isotherm at 1410 °C. A series of interrupted sintering trials was performed with the aim of studying the sintering behavior and the microstructural evolution during both solid-state and liquid-state sintering. Reference samples, using the same elemental compositions but with the starting components TiC and ZrC instead of (Ti,ZrC, were also sintered. The microstructure was investigated using scanning electron microscopy and energy dispersive X-ray spectroscopy. It is found that the (Ti,ZrC phase decomposes into Ti-rich and Zr-rich nano-scale lamellae before the liquid-state of the sintering initiates. The final microstructure consists of the binder and WC as well as two different γ phases, rich in either Ti (γ1 or Zr (γ2. The γ2 phase grains have a core-shell structure with a (Ti,ZrC core following the full sintering cycle. The major differences observed in (Ti,ZrC with respect to the reference samples after the full sintering cycle were the referred core-shell structure and the carbide grain sizes; additionally, the microstructural evolution during sintering differs. The grain size of carbides (WC, γ1, and γ2 is about 10% smaller in WC-(Ti,ZrC-Co than WC-TiC-ZrC-Co. The shrinkage behavior and hardness of both composites are reported and discussed.

  7. Analysis of PTA hardfacing with CoCrWC and CoCrMoSi alloys

    Directory of Open Access Journals (Sweden)

    Adriano Scheid

    2013-12-01

    Full Text Available CoCrWC alloys are widely used to protect components that operate under wear and high temperature environments. Enhanced performance has been achieved with the CoCrMoSi alloys but processing this alloy system is still a challenge due to the presence of the brittle Laves phase, particularly when welding is involved. This work evaluated Plasma Transferred Arc coatings processed with the Co-based alloy CoMoCrSi - Tribaloy T400, reinforced with Laves phase, comparing its weldability to the CoCrWC - Stellite 6, reinforced with carbides. Coatings were also analyzed regarding the response to temperature exposure at 600°C for 7 days and subsequent effect on microstructure and sliding abrasive wear. Coatings characterization was carried out by light and scanning electron microscopy, X-ray diffraction and Vickers hardness. CoCrWC coatings exhibited a Cobalt solid solution dendritic microstructure and a thin interdendritic region with eutectic carbides, while CoCrMoSi deposits exhibit a large lamellar eutectic region of Laves phase and Cobalt solid solution and a small fraction of primary Laves phase. Although phase stability was observed by X-ray diffraction, coarsening of the microstructure occurred for both alloys. CoCrMoSi showed thicker lamellar Laves phase and CoCrWC coarser eutectic carbides. Coatings stability assessed by wear tests revealed that although the wear rate of the as-deposited CoCrMoSi alloy was lower than that of CoCrWC alloy its increase after temperature exposure was more significant, 22% against 15%. Results were discussed regarding the protection of industrial components in particular, bearings in 55AlZn hot dip galvanizing components.

  8. Due etimologie venete ed istriane

    Directory of Open Access Journals (Sweden)

    Alberto Zamboni

    1991-12-01

    Full Text Available Un isolato dialetto del Medio Agordino (La Valle, BL attesta per 'ginepro' (Juniperus eommunis L., d'altronde compattamente designato come dzené(iver, deneore il termine bozičo che richiama il busicio dato già per l'area bellunese dal Soravia (1877, 108. II Pellegrini (1964, 28 enota 51 ne riscontra il perfetto corrispondente del Veneto orientale buzíčo documentato al p. 356 (S. Stino di Livenza dali' AIS 599 e l'accosta senz'altro al padovano (in realtà piuttosto veneziano di terraferma brusiehio (eh = (č! segnalato dal Patriarchi (1821, ma I'ed. 1775 e che si giustificherebbe con l'intrusione di 'bruciare' dal noto usodi bruciare le bacche della pianta per suffumigi, cfr. il ted. regionale Feuerbaum (su cui Marzell 2/1972, 1091 e anche il tipo brusìn dell'alta Val di Sole (Pedrotti-Bertoldi 1931, 206s.. Si osservi che anche il grande repertorio poliglotta del Nemnich (3/1794, 267 dà esplicitamente brusichio per Venezia. Sul tipo e sull'etimo il Pellegrini ritorna più avanti (1982, 185 riassumendo la bibliografia precedente e aggiungendo documentazioni dall' ASLEF: bo/ič al p. 172 (Chions, PN e ancora nel friulano occidentale (in pratica sempre nella zona di confine col veneto sbrodicio, sbradicio a Budoia (AppiSanson 1970, 28;

  9. Influence of electrical discharge machining on the tribological characteristics of WC-Co alloys; Influencia de la electroerosion sobre las caracteristicas tribologicas de materiales compuestos WC-Co

    Energy Technology Data Exchange (ETDEWEB)

    Casas, B.; Martinez, E.; Esteve, J.; Anglada, M.; Llanes, L.

    2001-07-01

    The influence of electrical discharge machining (EDM) on the abrasive wear resistance of two WC-10 %{sub w}tCo cemented carbides with different carbide grain size has been studied. Different surface finish conditions were evaluated corresponding to sequential EDM as well as grinding and polishing with diamond. The abrasive wear resistance was determined through microscratch measurements using a nano indentation system. Contrary to the results obtained from hardness measurements, this techniques allows to discern tribological differences among the distinct surface finish conditions studied. Finally, the abrasive wear resistance degradation associated with sequential EDM is discussed as a function of microstructure in terms of a damage parameters. (Author) 9 refs.

  10. Exploring the potential role of tungsten carbide cobalt (WC-Co) nanoparticle internalization in observed toxicity toward lung epithelial cells in vitro.

    Science.gov (United States)

    Armstead, Andrea L; Arena, Christopher B; Li, Bingyun

    2014-07-01

    Tungsten carbide cobalt (WC-Co) has been recognized as a workplace inhalation hazard in the manufacturing, mining and drilling industries by the National Institute of Occupational Safety and Health. Exposure to WC-Co is known to cause "hard metal lung disease" but the relationship between exposure, toxicity and development of disease remain poorly understood. To better understand this relationship, the present study examined the role of WC-Co particle size and internalization on toxicity using lung epithelial cells. We demonstrated that nano- and micro-WC-Co particles exerted toxicity in a dose- and time-dependent manner and that nano-WC-Co particles caused significantly greater toxicity at lower concentrations and shorter exposure times compared to micro-WC-Co particles. WC-Co particles in the nano-size range (not micron-sized) were internalized by lung epithelial cells, which suggested that internalization may play a key role in the enhanced toxicity of nano-WC-Co particles over micro-WC-Co particles. Further exploration of the internalization process indicated that there may be multiple mechanisms involved in WC-Co internalization such as actin and microtubule based cytoskeletal rearrangements. These findings support our hypothesis that WC-Co particle internalization contributes to cellular toxicity and suggest that therapeutic treatments inhibiting particle internalization may serve as prophylactic approaches for those at risk of WC-Co particle exposure.

  11. GeneEd -- A Genetics Educational Resource

    Science.gov (United States)

    ... Javascript on. Feature: Genetics 101 GeneEd — A Genetics Educational Resource Past Issues / Summer 2013 Table of Contents Science ... The Hereditary Material of Life / GeneEd — A Genetics Educational Resource / Using The Genetics Home Reference Website / Understanding the ...

  12. The Effects of Using Active Wheelchair (AWC and Standard Wheelchair (SWC on Physical Performance - Choosing Appropriate Wheelchair (WC

    Directory of Open Access Journals (Sweden)

    Ebubekir A K S A Y

    2014-09-01

    Full Text Available The aim of WC exercises is to acquire technical skills required for using WC correctly, and to help improve the physical performance . This study has been carried out in order to investigate the effects of AWC and SWC exercises on physical performances and technical skills of obese individuals having no movement limitation in their upper extremities . In this study, 41 WC users (20 AWC users and 21 SWC users aged between 18 and 26 years, and having no movement limitation in their upper extremities have been involved . For 16 weeks, a 50 min WC activity program (technique, distance walking, and effort has been implemented 3 times a week . IBM SPSS 21 software has been used for statistical analyses, while t - test ha s been utilized for standard deviation, mean value and comparisons, and the level of significance has been set as p<0. 05. After the 16 - weeks physical activity program, increases in WC usage techniques, balance skills, and physical performance have been obs erved . In all of tests performed, AWC group showed better performance than SWC group . It has been found that the users especially in SWC group have ache in back, shoulders, arms, and wrists . Physical activities with an appropriate WC improve the mobility, decrease pain in back, shoulders and wrists, and balance the energy consumption . This study shows that 50 - mil daily physical activities would contribute to WC usage techniques of AWC users, and their physical performances. This could be an important factor in eliminating the possible injuries .

  13. A comparison of the DPSS UV laser ablation characteristic of 1024 and H10F WC-Co

    Science.gov (United States)

    See, Tian Long; Chantzis, Dimitrios; Royer, Raphael; Metsios, Ioannis; Antar, Mohammad; Marimuthu, Sundar

    2017-07-01

    An investigation on ablation characteristics of 1024 and H10F cobalt cemented tungsten carbide (WC-Co) with a DPSS nanosecond UV laser (50 ns pulse width, 355 nm wavelength, 90 W average power and 10 kHz repetition rate) is presented. The ablation characteristic parameters such as ablation threshold, incubation effect and optical penetration depth were evaluated based on the spot ablation diameter and depth. It was observed that the ablation threshold is significantly influenced by the number of pulses (NOP) and it decreases with increase NOP which is attributed to the incubation effect. Only one ablation region is observed at low laser fluence and an additional molten ablation region is observed at high laser fluence accompanied with cracks. The cracks formation is due to the thermal induced stress and changes in WC microstructure during laser beam irradiation. The crack depth is proportional to the thickness of the molten WC region. The ablation threshold of 1024 WC-Co and H10F WC-Co were found to be Fth1 =4.32 J/cm2 and Fth1 =4.26 J/cm2 respectively. The difference in chemical composition has insignificant effect on the ablation threshold value of the material. The incubation factor and optical penetration depth values of 1024 WC-Co and H10F WC-Co were found to be ξ=0.73, α-1 =411 nm and ξ=0.75, α-1 =397 nm respectively.

  14. Technology Optimized Test on the Cutter of Agricultural Machine by Flame Spraying and Remelting NiWC Alloy

    Institute of Scientific and Technical Information of China (English)

    HAO Jian-jun; LI Hui-ping; MA Yue-jin; SHEN Yu-zeng

    2004-01-01

    In order to solve the problemof the machine for chopping and returning stubble into soil high-priced and short-lifetime, wear-resistance coating was made on the substrate of 45# steel by flame spraying and remelting NiWC alloy. By means of orthogonal test and multiple factors variance analysis, how the test factors influence the wear-resistance was studied.The technology parameters of flame spraying and remelting NiWC alloy were optimized as follows: coating matching,65% Ni60+ 35% WC; preheat temperature ,450 ℃; acetylene flow, 1000 L/h; spraying distance ,40 mm.

  15. Evaluation of fatigue strength of WC cermet- and 13Cr steel-sprayed materials; WC cermet oyobi 13Cr ko yosha hifukuzai no hiro kyodo hyoka

    Energy Technology Data Exchange (ETDEWEB)

    Ogawa, T.; Tokaji, K.; Ejima, T. [Gifu University, Gifu (Japan); Kobayashi, Y.; Harada, Y. [Tocalo Co. Ltd., Kobe (Japan)

    1997-10-15

    Rotating bending fatigue tests have been conducted at room temperature in air using the specimens of medium carbon steel (S45C), low alloy steel (SCM435) and titanium alloy (Ti-6Al-4V) with HVOF sprayed coating of a cermet (WC-12%Co) and S45C with WFS sprayed coating of a 13Cr steel (SUS420 J2). The fatigue strength and fracture mechanisms were studied. The fatigue strength evaluated by nominal stress was strongly influenced by substrate materials and the thickness of sprayed coatings. Detailed observation of crack initiation on the coating surface and fracture surface revealed that microcracks initiated at the WC grain boundary coalesced, and then the crack grew rapidly in the coating. Cracks in the substrate were initiated by the stress concentration of the crack in the coating, which was modeled by finite element analysis. For the specimens tested in this study, the fatigue strength of sprayed specimens was dominated by that of sprayed coating. Thus, the fatigue strength could be evaluated uniquely by the true stress on the coating surface. 9 refs., 12 figs., 2 tabs.

  16. Phase Analysis of Cemented Carbide WC-Co Boronised with Yttrium

    Institute of Scientific and Technical Information of China (English)

    刘寿荣; 郝建民; 褚连青; 宋俊亭

    2002-01-01

    Phase analysis for the coated surface with B4C and Y2O3 of cemented carbid e WC-20Co in vacuum-heating was carried out by high-temperature X-ray diffra ction from ambient temperature to 1300 ℃. The results show that, the high-conc entration active boron atoms are released from the boron-supply agent B4C loc ated on the alloy surface and diffused into the γ-phase, leading to forming th e three-element boron-bearing compound W2Co21B6 beside forming boron -bearing compounds on the blank surface. By contrast with boronising only, the element yttrium in boronization broadens the boronising temperature range during vacuum-sintering, catalyzes the decarbonisation decomposition of B4C and prom otes diffusion of active boron atoms into the bulk of WC-Co.

  17. Experimental investigation of surface quality in ultrasonic machining of WC-Co composites through Taguchi method

    Directory of Open Access Journals (Sweden)

    B. S. Pabla

    2016-08-01

    Full Text Available In manufacturing industries, the demand of WC-Co composite is flourishing because of the distinctive characteristics it offers such as: toughness (with hardness, good dimensional stability, higher mechanical strength etc. However, the difficulties in its machining restrict the application and competitiveness of this material. The current article has been targeted at evaluation of the effect of process conditions (varying power rating, cobalt content, tool material, part thickness, tool geometry, and size of abrasive particle on surface roughness in ultrasonic drilling of WC-Co composite. Results showed that abrasive grit size is most influential factor. From the microstructure analysis, the mode of material deformation has been observed and the parameters, i.e. work material properties, grit size, and power rating was revealed as the most crucial for the deformation mode.

  18. Cross-sectional AEM preparation technique for ceramic-coated WC-Co cutting tools.

    Science.gov (United States)

    Ostreicher, K; Sung, C

    1993-04-15

    The preparation of cross-sectional specimens for AEM studies of materials such as ceramic coated tungsten carbide presents some unique problems. Pieces joined by the use of epoxides often separate at the interface between the WC and ceramic coating during the initial mechanical grinding and subsequent thinning process as a result of the vibration and physical strain placed on the sample. These problems have been overcome through the use of a preparation process which essentially encapsulates the sample within the confines of an epoxy filled quartz tube. This preparation process has allowed for facile AEM cross-sectional analysis of TiN/TiCN coatings on WC-Co substrates, and has revealed two distinct grain morphologies within the TiCN coating.

  19. Microwave Sintering of A12O3-ZrO2-WC-Co Cermets

    Institute of Scientific and Technical Information of China (English)

    GU Tianben; LU hongzhi

    2011-01-01

    Composite powders of nanocrystalline WC-10Co (15wt%), Y2O3 (8mo1%) stabilized nanocrystalline ZrO2 (30wt%), industrial cobalt powder (4.5wt%) and submicron A12O3 (55wt%)composite powders were fabricated by high-energy ball-milling process. The nanocomposite powders were consolidated by microwave sintering process at temperature ranged 1300 ℃-1550 ℃ for 15 min,respectively. The optimum consolidation conditions, such as temperature, were researched during microwave sintering process. Vickers Hardness of the consolidated cermets was measured by using a Vickers indentation test, and density of specimens was also determined by Archimedes' principle.Microwave sintering process could not only increase the density of A12O3-ZrO2-WC-Co cermets and reduce the porosity, but also inhibit abnormal grain growth.

  20. Mechanical performance of alumina reinforced with NbC, TiC and WC

    Directory of Open Access Journals (Sweden)

    Wilson Acchar

    2012-12-01

    Full Text Available The incorporation of refractory hard particles in Al2O3-based composites may inhibit grain growth of the matrix, which could significantly contribute to mechanical performance of the composite. The present study aimed to investigate the potential use of NbC as alumina reinforcing material, as an alternative to other carbides such as TiC and WC. Alumina was mixed with a fixed carbide concentration of 30 wt.(% in a ball mill and uniaxially hot-pressed at 1650 ºC under a load of 30 MPa in an inert atmosphere. X-ray diffraction revealed no oxidation products were present after the sintering process. Microstructure analyses indicate a homogeneous carbide distribution in the alumina matrix. Results obtained in this study show that alumina reinforced with NbC is a composite material with properties comparable to those of alumina reinforced with WC and TiC, thereby making it good reinforcing material.

  1. Adhesion strength of sputtered TiAlN-coated WC insert tool

    Energy Technology Data Exchange (ETDEWEB)

    Budi, Esmar [Department of Physics, Faculty of Science and Mathematics, Universitas Negeri Jakarta, Jl. Pemuda No. 10, Jakarta 13220 (Indonesia); Razali, M. Mohd.; Nizam, A. R. Md. [Faculty of Manufacturing Engineering, Universiti Teknikal Malaysia Melaka Karung Berkunci No 1752 Pejabat Pos Durian Tunggal 76109 Melaka (Malaysia)

    2013-09-09

    The adhesion strength of TiAlN coating that deposited by using DC magnetron sputtering on WC insert tool are studied. TiAlN coating are deposited on Tungsten Carbide (WC) insert tool by varying negatively substrate bias from 79 to 221 volt and nitrogen flow rate from 30 to 72 sccm. The adhesion strength are obtained by using Rockwell indentation test method with a Brale diamond at applied load of 60,100 and 150 kgf. The lateral diameter of indentation is plotted on three different applied loads and the adhesion strength of TiAlN coating was obtained from the curved slopes at 100 and 150 kgf. The lower curve slop indicated better adhesion strength. The results shows that the adhesion strength of sputterred TiAlN coating tend to increase as the negatively substrate bias and nitrogen flow rate are increased.

  2. Structure and Abrasive Wear of Composite HSS M2/WC Coating

    Directory of Open Access Journals (Sweden)

    S. F. Gnyusov

    2012-01-01

    Full Text Available Features of phase-structure formation and abrasive wear resistance of composite coatings “WC-M2 steel” worn against tungsten monocarbide have been investigated. It was established that adding 20 wt.% WC to the deposited powder mixture leads to the increase in M6C carbide content. These carbides show a multimodal size distribution consisting of ~5.9 μm eutectic carbides along the grain boundaries, ~0.25 μm carbides dispersed inside the grains. Also a greater amount of metastable austenite (~88 vol.% is found. The high abrasive wear resistance of these coatings is provided by γ→α′-martensitic transformation and multimodal size distribution of reinforcing particles.

  3. WC-NiP复合材料在腐蚀条件下的磨损性能%WEAR PERFORMANCE OF WC-NiP COMPOSITES UNDER CORROSION CONDITION

    Institute of Scientific and Technical Information of China (English)

    曾涛

    2005-01-01

    对新开发的一种机械密封新型摩擦副WC-NiP复合材料的腐蚀磨损性能进行了研究.考察了WC-NiP与浸呋喃树脂石墨在3%NaCl、10%HCl和卤水中的腐蚀磨损性能.结果表明:WC-NiP复合材料在此配对情况下多发生粘着磨损,WC-NiP复合材料可作为低浓度非氧化酸性介质和卤水中的首选材料.

  4. Preparation, Microstructure and Performance of WC-Ni Reinforced Fe-based Graded Coating%WC-Ni增强Fe基梯度涂层的制备及组织性能

    Institute of Scientific and Technical Information of China (English)

    袁有录; 李铸国

    2012-01-01

    利用等离子熔覆同轴双筒送粉工艺,在Q235基板上制备了多层WC-Ni成分渐变的梯度涂层,结果表明:涂层中WC颗粒大部分被溶解,在随后的快速冷却中,有两类碳化物组织析出,组织特征与WC-Ni的含量有关.当WC-Ni含量小于20%时,析出粗大树枝晶基体混合片层状共晶碳化物组织;当WC-Ni含量大于30%时,析出块状初生碳化物组织.未完全溶解的WC颗粒呈圆角形,并与基体之间形成合金过渡层.梯度涂层中各层间形成了冶金过渡,其主要物相有γ-Fe、WC、Fe3C、Fe3W3C、Cr7C3.涂层的硬度明显高于基体,但受WC的溶解及析出碳化物的大小及分布不均影响,梯度涂层的硬度分布波动起伏较大.%A multilayer graded coating of WC-Ni reinforced Fe-based matrix was prepared on Q235 steel plate by plasma cladding with a coaxial feeding powder system. Results show that most of the WC particles are dissolved in the Fe-based matrix, and two types of carbides are precipitated in the follow cooling stage. One is coarse dendrites mixed with lamellar eutectics carbides when WC-Ni content is less than 20% ; the other is polygonal block primary carbides when WC-Ni content is more than 30%. The half-dissolved WC particles are all with round angles, and an alloy reaction layer forms between the particles and the matrix. The main phases of the coating are γ- Fe, WC, Fe3C, Fe3W3C, and Cr7C3. Microhardness of the graded coating is higher than that of the substrate; however is fluctuated through the coating due to the dissolution of WC and the inhomogeneous distribution of the precipitated carbides.

  5. Characteristics of dissimilar laser-brazed joints of isotropic graphite to WC-Co alloy

    Energy Technology Data Exchange (ETDEWEB)

    Nagatsuka, Kimiaki, E-mail: nagatuka@jwri.osaka-u.ac.jp [Graduate School of Engineering, Osaka University, Joining and Welding Research Institute, 11-1, Mihogaoka, Ibaraki, Osaka 567-0047 (Japan); Sechi, Yoshihisa, E-mail: sechi@kagoshima-it.go.jp [Kagoshima Prefectural Institute of Industrial Technology, 1445-1 Oda, Hayato-cho, Kirishima, Kagoshima 899-5105 (Japan); Miyamoto, Yoshinari, E-mail: y_miyamoto@toyotanso.co.jp [Toyo Tanso Co., Ltd., 5-7-12 Takeshima, Nishiyodgawa-ku, Osaka 555-0011 (Japan); Nakata, Kazuhiro, E-mail: nakata@jwri.osaka-u.ac.jp [Joining and Welding Research Institute, Osaka University, 11-1, Mihogaoka, Ibaraki, Osaka 567-0047 (Japan)

    2012-04-25

    Highlights: Black-Right-Pointing-Pointer Ti was required in the filler metal for brazing graphite to WC-Co alloy. Black-Right-Pointing-Pointer The shear strength of the joint increased with Ti content up to 1.7 mass%. Black-Right-Pointing-Pointer Ti concentrated at the interface of graphite/filler metal. Black-Right-Pointing-Pointer TiC was formed at the interface of graphite/filler metal. - Abstract: The effect of Ti serving as an activator in a eutectic Ag-Cu alloy filler metal in dissimilar laser-brazed joints of isotropic graphite and a WC-Co alloy on the joint strength and the interface structure of the joint is investigated in this study. To evaluate the joint characteristics, the Ti content in the filler metal was increased from 0 to 2.8 mass%. The laser brazing was carried out by irradiating a laser beam selectively on the WC-Co alloy plate in Ar atmosphere. The threshold content of Ti required to join isotropic graphite to WC-Co alloy was 0.4 mass%. The shear strength at the brazed joint increased rapidly with increasing Ti content up to 1.7 mass%, and a higher Ti content was found to be likely to saturate the shear strength to a constant value of about 14 MPa. The isotropic graphite blocks also fractured at this content. The concentration of Ti observed at the interface between isotropic graphite and the filler metal indicates the formation of an intermetallic layer of TiC.

  6. The Effectof Insert of WC Powder on the Surface Hardening of Non Magnetic Foundry Materials

    OpenAIRE

    Ike, Hiroyuki; Shobuzawa, Yoshiyuki; Goto, Shoji; Aso, Setsuo; Konishi, Nobuo

    2002-01-01

    Non magnetic foundry materials such as the austenitic stainless cast steel had not been used for abrasion resistant materials, because their hardnesses were very low. Usually, ceramics, cermets and cemented carbides are used for the abrasion resistant materials even though they are expensive compared with foundry materials. In this study, WC powder were inserted by using the austenitic stainless cast steel (JIS SCS13A) and the austenitic cast iron (JIS FCA-NiCr202) for producing surface ha...

  7. WC as a non-platinum hydrogen evolution electrocatalyst for high temperature PEM water electrolysers

    DEFF Research Database (Denmark)

    Nikiforov, Aleksey; Petrushina, Irina; Christensen, Erik

    2012-01-01

    Tungsten carbide (WC) nanopowder was tested as a non-platinum cathode electrocatalyst for polymer electrolyte membrane (PEM) water electrolysers, operating at elevated temperatures. It was prepared in thermal plasma reactor with confined plasma jet from WO3 precursor in combination with CH4...... carburizing agent. The results of the investigation showed that the activity of tungsten carbide as cathode electrocatalyst increases significantly with temperature and this effect is more pronounced than for platinum, especially, at 150 °C....

  8. The Electro-Spark Deposited WC-Cu Coatings Modified by Laser Treatment / Powłoki WC-Cu Naniesione Elektroiskrowo I Modyfikowane Obróbką Laserową

    OpenAIRE

    Radek N.; Konstanty J.; Scendo M.

    2015-01-01

    The main objective of the present work was to determine the influence of laser treatment on microstructure, X-ray diffraction, microhardness, surface geometric structure and roughness, corrosion resistance and tribological properties of coatings deposited on C45 carbon steel by the electro-spark deposition (ESD) process. The studies were conducted using WC-Cu electrodes produced by the powder metallurgy route. The tests show that the laser-treated electro-spark deposited WC-Cu coatings are ch...

  9. Physical Properties of Diamond Coatings on a WC-6%Co Substrate

    Institute of Scientific and Technical Information of China (English)

    刘沙; 易丹青; 余志明

    2002-01-01

    We have investigated the physical properties, including the morphology, texture, adhesion and chemical quality,of high-frequency chemical vapour deposited diamond coatings on WC-6%Co substrates, which were pre-treated by a two-step etching method. The results indicate that the increasing Co content from 0.12 to 3.05% within the etching depth of Sμmn caused a morphology transformation from prism diamond to spherulitic diamond, and a texture transformation from a {111} orientation to a {110} orientation. The Raman spectrum shows that the spherulitic diamond film contains more non-diamond phases (graphite, amorphous carbon and diamond-like carbon, etc) and has lower chemical quality than diamond films on a WC-6%Co substrate. The diamond coating grain sizes became about four times smaller when the deposition temperatures on the substrate surface were reduced from 1000 to 900° C. Compared with spherulitic diamond films, the prism diamond films exhibit better adhesion on the WC-6%Co substrate.

  10. Chemical pretreatments at surface of WC-6% Co for diamond coatings

    Institute of Scientific and Technical Information of China (English)

    刘沙; 易丹青; 余志明; 卢斌; 王建华

    2002-01-01

    The WC-6%Co(mass fraction) substrate surfaces were chemically pretreated with the two-step etching method, using Murakami reagent for 3~7min, and then an φ(HNO3)∶φ(HCl)=4∶1 solution for 1~15min. Diamond films were deposited on the substrates by a hot-filament chemical vapor deposition reactor. The results show that the Co content of the substrate surfaces can be reduced from 6% to 0.12% within the etching depth of 5~10μm, the surface roughness of the substrates is increased up to Ra=1.0μm, as well as the substrates hardness is decreased from HRA 89.5 to HRA 84.2 after the two-step etching. A slight preference towards {111} orientation can be observed from the XRD patterns and SEM micrograph of diamond film on WC-6%Co sample. The morphology of small rice-like ballas diamond was observed on the WC-6%Co substrates. A typical Raman spectrum with a sharp peak at 1332cm-1 for the diamond film indicates that the deposited films are good-quality polycrystalline diamond. The indentation testing shows that the adhesion between diamond film and the substrate after HF CVD deposition is good.

  11. The Peculiar Type Ib Supernova 2006jc: A WC Star Explosion

    CERN Document Server

    Tominaga, N; Suzuki, T; Tanaka, M; Nomoto, K; Maeda, K; Chieffi, A; Tornambé, A; Minezaki, T; Yoshii, Y; Sakon, I; Wada, T; Ohyama, Y; Tanabé, T; Kaneda, H; Onaka, T; Nozawa, T; Kozasa, T; Kawabata, K S; Anupama, G C; Sahu, D K; Gurugubelli, U K; Prabhu, T P; Deng, J

    2007-01-01

    We present a theoretical model for Type Ib supernova (SN) 2006jc associated with a luminous blue variable (LBV)-like event. We calculate the presupernova evolution of the progenitor star, hydrodynamics and nucleosynthesis of the SN explosion, and the SN bolometric light curve (LC). The observed bolometic LC is constructed by integrating the UV, optical, near-infrared (NIR), and mid-infrared (MIR) fluxes. The progenitor is assumed to be as massive as $40\\Msun$ on the zero-age. The star undergoes extensive mass loss to reduce its mass down to as small as $6.9\\Msun$, thus becoming a WC Wolf-Rayet star at the presupernova stage. The WC star model has a thick carbon-rich layer, in which amorphous carbon grains can be formed during the explosion. This could explain the brightening in the NIR flux and the observed dust feature in MIR. The typical main-sequence mass of a WC Wolf-Rayet star and thus the progenitor of SN 2006jc is more massive than $40\\Msun$. We suggest that the explosions of stars more massive than $4...

  12. DURABILITY AND TRIBOLOGICAL PROPERTIES OF THERMALLY SPRAYED WC CERMET COATING IN LUBRICATED ROLLING WITH SLIDING CONTACT

    Directory of Open Access Journals (Sweden)

    Mohammad Ali

    2010-09-01

    Full Text Available Durability and tribological properties of thermally sprayed WC-Cr-Ni cermet coating were investigated experimentally in lubricated rolling with sliding contact conditions. By means of the high energy type flame spraying (Hi-HVOF method, the coating was formed onto the axially ground and circumferentially ground roller specimens made of a thermally refined carbon steel. In the experiments, the WC cermet coated steel roller was mated with the carburized hardened steel roller without coating in line contact condition. The coated roller was mated with the smooth non-coated roller under a contact pressure of 1.0 or 1.2 GPa, and it was mated with the rough non-coated roller under a contact pressure of 0.6 or 0.8 GPa. As a result, it was found that in general, the coating on the circumferentially ground substrate shows a lower durability compared with that on the axially ground substrate and this difference appears more distinctly for the higher contact pressure for both smooth mating surface and rough mating surface. It was also found that there are significant differences in the tribological properties of WC cermet coating depending on the contact pressure. In addition, depending on the smooth or rough mating surface, remarkable differences in the tribological properties were found.

  13. Wear Evaluation of AISI 4140 Alloy Steel with WC/C Lamellar Coatings Sliding Against EN 8 Using Taguchi Method

    Science.gov (United States)

    Kadam, Nikhil Rajendra; Karthikeyan, Ganesarethinam

    2016-10-01

    The purpose of the experiments in this paper is to use the Taguchi methods to investigate the wear of WC/C coated nitrided AISI 4140 alloy steel. A study of lamellar WC/C coating which were deposited by a physical vapor deposition on nitrided AISI 4140 alloy steel. The investigation includes wear evaluation using Pin-on-disk configuration. When WC/C coated AISI 4140 alloy steel slides against EN 8 steel, it was found that carbon-rich coatings show much lower wear of the countersurface than nitrogen-rich coatings. The results were correlated with the properties determined from tribological and mechanical characterization, therefore by probably selecting the proper processing parameters the deposition of WC/C coating results in decreasing the wear rate of the substrate which shows a potential for tribological application.

  14. Effects of WC-17Co Coating Combined with Shot Peening Treatment on Fatigue Behaviors of TC21 Titanium Alloy

    National Research Council Canada - National Science Library

    Du, Dongxing; Liu, Daoxin; Zhang, Xiaohua; Tang, Jingang; Meng, Baoli

    2016-01-01

    ...) sprayed WC-17Co coating was investigated. X-ray diffraction (XRD) and the corresponding stress measurement instrument, a surface roughness tester, a micro-hardness tester, and a scanning electron microscope (SEM...

  15. Feasibility of using quadriceps-strengthening exercise to improve pain and sleep in a severely demented elder with osteoarthritis – a case report

    Directory of Open Access Journals (Sweden)

    Richards Kathy

    2002-10-01

    Full Text Available Abstract Background Osteoarthritis (OA of the knee, which is prevalent among older adults in nursing homes, causes significant pain and suffering, including disturbance of nocturnal sleep. One nonpharmacologic treatment option is quadriceps-strengthening exercise, however, the feasibility of such a treatment for reducing pain from OA in severely demented elders has not been studied. This report describes our test of the feasibility of such an exercise program, together with its effects on pain and sleep, in a severely demented nursing home resident. Case presentation The subject was an elderly man with severe cognitive impairment (Mini-Mental Status Exam score 4 and knee OA (Kellgren-Lawrence radiographic grade 4. He was enrolled in a 5-week, 10-session standardized progressive-resistance training program to strengthen the quadriceps, and completed all sessions. Pain was assessed with the Western Ontario and MacMaster OA Index (WOMAC pain subscale, and sleep was assessed by actigraphy. The patient was able to perform the exercises, with a revision to the protocol. However, the WOMAC OA pain subscale proved inadequate for measuring pain in a patient with low cognitive functioning, and therefore the effects on pain were inconclusive. Although his sleep improved after the intervention, the influence of his medications and the amount of daytime sleep on his nighttime sleep need to be considered. Conclusions A quadriceps-strengthening exercise program for treating OA of the knee is feasible in severely demented elders, although a better outcome measure is needed for pain.

  16. A theoretical understanding on the CO-tolerance mechanism of the WC(0001) supported Pt monolayer: Some improvement strategies

    Science.gov (United States)

    Zhang, Xilin; Lu, Zhansheng; Yang, Zongxian

    2016-12-01

    The deposition of platinum on the tungsten carbide (Pt/WC) have been achieved and proved with high stability, activity and CO-tolerance toward some reactions in experiments. Although a lot of experimental efforts have been focused on understanding the activity, stability and CO-tolerance of Pt/WC, the relevant theoretical works related to the CO-tolerance mechanism are still scarce. In current study, the adsorption and oxidation of CO on the Pt monolayer supported on WC(0001) surface (PtML/WC(0001)) are investigated using density functional theory calculations. It is found that the oxidation of CO on PtML/WC(0001) proceeds preferably along the Langmuir-Hinshelwood mechanism. The energy barrier of 1.06 eV for the rate-determining step of OOCO formation is almost equal to that (1.05 eV) for CO oxidation by atomic O on Pt(111), while the adsorption energy of 1.59 eV for CO on PtML/WC(0001) is smaller than that on Pt(111) (1.85 eV), indicating that the high resistance to CO poisoning of PtML/WC(0001) may originate from the weak interaction between them. To further improve the CO tolerance, some probable strategies are proposed based on the relevant kinetics results. The current results are helpful to understanding the origin of the highly resistant to CO poisoning of PtML/WC(0001) and rationally designing catalysts to improve the CO oxidation activity.

  17. Oxidation behavior of Fe40Al-xWC composite coatings obtained by high-velocity oxygen fuel thermal spray

    Institute of Scientific and Technical Information of China (English)

    XIANG Jun-huai; ZHU Xing-he; CHEN Gang; DUAN Zhi; LIN Yan; LIU Ying

    2009-01-01

    The Fe40Al-xWC (x=0,10,12,15) coatings with dense structure were successfully deposited by high-velocity oxygen fuel (HVOF) spraying of a mixture of Fe,Al and WC powders.The objective of the present work is to provide insight into the oxidation behavior of the as-deposited coatings at 650 ℃ under 0.1 Mpa flowing pure O_2.The present results show differences in the oxidation behavior of Fe40Al coating and Fe40Al-xWC composite coatings.The irregular Fe_2O_3 layer is seen on the top surface of the composite coatings.Fe40Al coating and Fe40Al-15WC composite coating both suffer a catastrophic corrosion due to the formation of a porous structure during 24 h of oxidation.However,Fe40Al-10WC and Fe40Al-12WC composite coatings show a good oxidation resistance behavior due to their dense structure.

  18. Research on plasma sprayed high friction WC+Co coating%等离子喷涂高摩擦系数WC+Co涂层研究

    Institute of Scientific and Technical Information of China (English)

    乔斌

    2000-01-01

    选用4种不同颗粒度的WC+Co粉末,以得到不同粗糙度的表面涂层,测量其本身相对滑动摩擦系数和对钛合金相对滑动摩擦系数,结果表明不加栽荷时表面粗糙度与摩擦系数关系密切,其摩擦系数最高达1.42;当加载荷时涂层本身之间的摩擦系数高于涂层与钛合金的摩擦系数,钛合金之间的摩擦系数最小.同时讨论了结合力和摩擦之间的关系.

  19. "What do people do if they don't have insurance?": ED to ED Referrals.

    Science.gov (United States)

    Medford-Davis, Laura N; Prasad, Siddharth; Rhodes, Karin V

    2017-08-28

    Up to 20% of patients seen in public emergency departments (EDs) have already been seen for the same complaint at another ED, but little is known about the origin or impact of these duplicate ED visits. The goals of this investigation were to explore (1) whether patients making a repeat ED visit are self-referred or indirectly referred from the other ED; and (2) gather the perspective of affected patients on the health, social, and financial consequences of these duplicate ED visits. This mixed-methods study conducted over a 10-week period during 2016 in a large public hospital ED in Texas prospectively surveyed patients seen in another ED for the same chief complaint. Selected patients presenting with fractures were then enrolled for semi-structured qualitative interviews, which were audiotaped, transcribed, and independently coded by two team members until thematic saturation was reached. 143 patients were identified as being recently seen at another local ED for the same chief complaint prior to presenting to the public hospital; 94% were uninsured and 61% presented with fractures. 27% required admission at the public ED and 95% of those discharged required further outpatient follow-up. 51 patients completed a survey and qualitative interviews were conducted with 23 fracture patients. 53% of patients reported that staff at the first hospital told them to go the public hospital ED, and 23% reported referral from a follow-up physician associated with the first hospital. 73% reported receiving the same tests at both EDs. Interview themes identified multiple healthcare visits for the same injury, concern about complications, disrespectful treatment at the first ED, delayed care, problems accessing needed follow-up care without insurance, loss of work, and financial strain. The majority of patients presenting to a public hospital ED after treatment for the same complaint in another local ED were indirectly referred to the public ED without transferring paperwork or

  20. Influence of nano-CeO2 on the structure and corrosion resistance property of Pb-WC-CeO2 composite coating%纳米CeO2对Pb-WC-CeO2复合镀层结构及耐腐蚀性的影响

    Institute of Scientific and Technical Information of China (English)

    杜重麟

    2014-01-01

    By analyzing the cathodic polarization curves,AC impedance spectroscopy,Tafel curves,surface morphology,EDS curves, and the influence of CeO2 composition on the structure and corrosion resistance property of Pb-WC-CeO2 composite coating was studied. The results show that:the addition of CeO2 can improve the cathodic polarization and promote the co-deposition of WC ef-fectively. Besides,we can obtain coating with smaller crystal uniformer surface and better binding force by adding CeO2. When the CeO2 composition in bath is 40 g·L-1 the surface micromorphology of the coating is in best properties,and the mass percentage of Ce and W are 8. 75wt%,3. 18wt%,respectively. However,the relationship between the mass percentage of the two elements and CeO2 composition in bath is non-linearity.%通过对阴极极化曲线、交流阻抗测试技术和塔菲尔曲线的测量,以及镀层微观形貌和能谱图的分析,考察了在电解液中添加不同浓度的纳米CeO2对Pb-WC-CeO2复合镀层微观结构和耐腐蚀性能的影响。结果表明:CeO2的加入,可增大阴极极化,有效促进WC的共沉积,使镀层晶粒更细,表面更均匀平整,有良好的结合力;当其浓度为40 g·L-1时,镀层表面微观形貌最均匀致密,平整有序,有最好的耐蚀性能,镀层中Ce和W含量达到最大值8.75wt%和3.18%,但W和Ce元素的含量与溶液中CeO2的浓度并不完全呈线性变化。

  1. On the quantitativeness of EDS STEM

    Energy Technology Data Exchange (ETDEWEB)

    Lugg, N.R. [Institute of Engineering Innovation, The University of Tokyo, 2-11-16, Yayoi, Bunkyo-ku, Tokyo 113-8656 (Japan); Kothleitner, G. [Institute for Electron Microscopy and Nanoanalysis, Graz University of Technology, Steyrergasse 17, 8010 Graz (Austria); Centre for Electron Microscopy, Steyrergasse 17, 8010 Graz (Austria); Shibata, N.; Ikuhara, Y. [Institute of Engineering Innovation, The University of Tokyo, 2-11-16, Yayoi, Bunkyo-ku, Tokyo 113-8656 (Japan)

    2015-04-15

    Chemical mapping using energy dispersive X-ray spectroscopy (EDS) in scanning transmission electron microscopy (STEM) has recently shown to be a powerful technique in analyzing the elemental identity and location of atomic columns in materials at atomic resolution. However, most applications of EDS STEM have been used only to qualitatively map whether elements are present at specific sites. Obtaining calibrated EDS STEM maps so that they are on an absolute scale is a difficult task and even if one achieves this, extracting quantitative information about the specimen – such as the number or density of atoms under the probe – adds yet another layer of complexity to the analysis due to the multiple elastic and inelastic scattering of the electron probe. Quantitative information may be obtained by comparing calibrated EDS STEM with theoretical simulations, but in this case a model of the structure must be assumed a priori. Here we first theoretically explore how exactly elastic and thermal scattering of the probe confounds the quantitative information one is able to extract about the specimen from an EDS STEM map. We then show using simulation how tilting the specimen (or incident probe) can reduce the effects of scattering and how it can provide quantitative information about the specimen. We then discuss drawbacks of this method – such as the loss of atomic resolution along the tilt direction – but follow this with a possible remedy: precession averaged EDS STEM mapping. - Highlights: • Signal obtained in EDS STEM maps (of STO) compared to non-channelling signal. • Deviation from non-channelling signal occurs in on-axis experiments. • Tilting specimen: signal close to non-channelling case but atomic resolution is lost. • Tilt-precession series: non-channelling signal and atomic-resolution features obtained. • Associated issues are discussed.

  2. Temporal Lobe and Frontal-Subcortical Dissociations in Non-Demented Parkinson's Disease with Verbal Memory Impairment.

    Directory of Open Access Journals (Sweden)

    Jared J Tanner

    Full Text Available The current investigation examined verbal memory in idiopathic non-dementia Parkinson's disease and the significance of the left entorhinal cortex and left entorhinal-retrosplenial region connections (via temporal cingulum on memory impairment in Parkinson's disease.Forty non-demented Parkinson's disease patients and forty non-Parkinson's disease controls completed two verbal memory tests--a wordlist measure (Philadelphia repeatable Verbal Memory Test and a story measure (Logical Memory. All participants received T1-weighted and diffusion magnetic resonance imaging (3T; Siemens sequences. Left entorhinal volume and left entorhinal-retrosplenial connectivity (temporal cingulum edge weight were the primary imaging variables of interest with frontal lobe thickness and subcortical structure volumes as dissociating variables.Individuals with Parkinson's disease showed worse verbal memory, smaller entorhinal volumes, but did not differ in entorhinal-retrosplenial connectivity. For Parkinson's disease entorhinal-retrosplenial edge weight had the strongest associations with verbal memory. A subset of Parkinson's disease patients (23% had deficits (z-scores < -1.5 across both memory measures. Relative to non-impaired Parkinson's peers, this memory-impaired group had smaller entorhinal volumes.Although entorhinal cortex volume was significantly reduced in Parkinson's disease patients relative to non-Parkinson's peers, only white matter connections associated with the entorhinal cortex were significantly associated with verbal memory performance in our sample. There was also no suggestion of contribution from frontal-subcortical gray or frontal white matter regions. These findings argue for additional investigation into medial temporal lobe gray and white matter connectivity for understanding memory in Parkinson's disease.

  3. Plant immunity: the EDS1 regulatory node.

    Science.gov (United States)

    Wiermer, Marcel; Feys, Bart J; Parker, Jane E

    2005-08-01

    ENHANCED DISEASE SUSCEPTIBILITY 1 (EDS1) and its interacting partner, PHYTOALEXIN DEFICIENT 4 (PAD4), constitute a regulatory hub that is essential for basal resistance to invasive biotrophic and hemi-biotrophic pathogens. EDS1 and PAD4 are also recruited by Toll-Interleukin-1 receptor (TIR)-type nucleotide binding-leucine rich repeat (NB-LRR) proteins to signal isolate-specific pathogen recognition. Recent work points to a fundamental role of EDS1 and PAD4 in transducing redox signals in response to certain biotic and abiotic stresses. These intracellular proteins are important activators of salicylic acid (SA) signaling and also mediate antagonism between the jasmonic acid (JA) and ethylene (ET) defense response pathways. EDS1 forms several molecularly and spatially distinct complexes with PAD4 and a newly discovered in vivo signaling partner, SENESCENCE ASSOCIATED GENE 101 (SAG101). Together, EDS1, PAD4 and SAG101 provide a major barrier to infection by both host-adapted and non-host pathogens.

  4. Crack initiation and propagation behavior of WC particles reinforced Fe-based metal matrix composite produced by laser melting deposition

    Science.gov (United States)

    Wang, Jiandong; Li, Liqun; Tao, Wang

    2016-08-01

    It is generally believed that cracks in metal matrix composites (MMC) parts manufacturing are crucial to the reliable material properties, especially for the reinforcement particles with high volume fraction. In this paper, WC particles (WCp) reinforced Fe-based metal matrix composites (WCp/Fe) were manufactured by laser melting deposition (LMD) technology to investigate the characteristics of cracks formation. The section morphology of composites were analyzed by optical microscope (OM), and microstructure of WCp, matrix and interface were analyzed by X-ray diffraction (XRD) and scanning electron microscopy (SEM), in order to study the crack initiation and propagation behavior under different laser process conditions. The temperature of materials during the laser melting deposition was detected by the infrared thermometer. The results showed that the cracks often appeared after five layers laser deposition in this experiment. The cracks crossed through WC particles rather than the interface, so the strength of interface obtained by the LMD was relatively large. When the thermal stress induced by high temperature gradient during LMD and the coefficient of thermal expansion mismatch between WC and matrix was larger than yield strength of WC, the cracks would initiate inside WC particle. Cracks mostly propagated along the eutectic phases whose brittleness was very large. The obtained thin interface was beneficial to transmitting the stress from particle to matrix. The influence of volume fraction of particles, laser power and scanning speed on cracks were investigated. This paper investigated the influence of WC particles size on cracks systematically, and the smallest size of cracked WC in different laser processing parameters was also researched.

  5. Microstructure and property of sub-micro WC-10%Co particulate reinforced Cu matrix composites prepared by selective laser sintering

    Institute of Scientific and Technical Information of China (English)

    GU Dong-dong; SHEN Yi-fu; DAI Peng; YANG Ming-chuan

    2006-01-01

    The WC-10%Co particulate reinforced Cu matrix composite material with a WC-Co:Cu mass ratio of 20:80 was successfully fabricated by selective laser sintering(SLS) process. The following optimal processing parameters were used: laser power of 700 W, scan speed of 0.06 m/s, scan line spacing of 0.15 mm, and powder layer thickness of 0.3 mm. The microstructure,composition, and phase of the laser processed material were investigated by scanning electron microscopy(SEM), X-ray diffraction(XRD), and energy dispersive X-ray(EDX) spectroscopy. The results show that the bonding mechanism of this process is liquid phase sintering. The Cu and Co act as the binder phase, while the WC acts as the reinforcing phase. The non-equilibrium effects induced by laser melting, such as high degrees of undercooling and high solidification rate, result in the formation of a metastable phase CoC0.25. The WC reinforcing particulates typically have three kinds of morphology. They are agglomerated and undissolved, incompletely separated and partially dissolved, separated and dissolved, which indicates that particle rearrangement acts as the dominant sintering mechanism for the larger WC, while dissolution-precipitation prevails for the smaller WC particles.Microhardness tester was used to determine the Vickers hardness across the cross-section of the laser sintered sample, with the average value being HV0.1268.5. However, the hardness varied considerably, which might be attributed to the WC segregation and the high solidification rate experienced by the molten pool.

  6. The IONORT-ISP-WC system: Inclusion of an electron collision frequency model for the D-layer

    Science.gov (United States)

    Settimi, Alessandro; Pietrella, Marco; Pezzopane, Michael; Bianchi, Cesidio

    2015-04-01

    The IONORT-ISP system (IONOspheric Ray-Tracing - IRI-SIRMUP-PROFILES) was recently developed and tested by comparing the measured oblique ionograms over the radio link between Rome (41.89°N, 12.48°E), Italy, and Chania (35.51°N, 24.02°E), Greece, with the IONORT-ISP simulated oblique ionograms (Settimi et al., 2013). The present paper describes an upgrade of the system to include: (a) electron-neutral collision have been included by using a collision frequency model that consists of a double exponential profile; (b) the ISP three dimensional (3-D) model of electron density profile grid has been extended down to the altitude of the D-layer; (c) the resolution in latitude and longitude of the ISP 3-D model of electron density profile grid has been increased from 2° × 2° to 1° × 1°. Based on these updates, a new software tool called IONORT-ISP-WC (WC means with collisions) was developed, and a database of 33 IONORT-ISP-WC synthesized oblique ionograms calculated for single (1-hop paths) and multiple (3-hop paths) ionospheric reflections. The IONORT-ISP-WC simulated oblique ionograms were compared with the IONORT-IRI-WC synthesized oblique ionograms, generated by applying IONORT in conjunction with the International Reference Ionosphere (IRI) 3-D electron density grid, and the observed oblique ionograms over the aforementioned radio link. The results obtained show that (1) during daytime, for the lower ionospheric layers, the traces of the synthesized ionograms are cut away at low frequencies because of HF absorption; (2) during night-time, for the higher ionospheric layers, the traces of the simulated ionograms at low frequencies are not cut off (very little HF absorption); (3) the IONORT-ISP-WC MUF values are more accurate than the IONORT-IRI-WC MUF values.

  7. The low excitation planetary nebulae Hudo1 and Hubi1 and their [WC10] central stars

    Directory of Open Access Journals (Sweden)

    M. Peña

    2005-01-01

    Full Text Available Se analizan datos espectroscópicos de alta y baja resolución de las nebulosas planetarias con estrella central [WC] tardía, HuDo 1 y HuBi 1. Ambos objetos pertenecen al disco galáctico y tienen velocidades radiales heliocéntricas de _12 km s 1 (HuDo 1 y 57 km s 1 (HuBi 1. El enrojecimiento logarítmico, c(Hβ, es de 2.04 para HuDo 1 y 1.22 para HuBi 1. Se deriva la composición química del plasma, obteniéndose log(O/H+12 = 8.43 y 8.57, y N/O = 0.2 y 0.1 para HuDo 1 y HuBi 1 respectivamente. HuBi 1 es la única NP excitada por una estrella [WC] muy tardía que muestra líneas intensas de He I. A partir de las líneas estelares, se deriva un tipo espectral [WC10] para ambas estrellas, aunque la estrella de HuBi 1 debe ser ligeramente más caliente para proporcionar suficientes fotones ionizantes de He0. Al comparar los parámetros estelares de estos objetos con los de objetos similares, se encuentra que las estrellas de HuDo 1 y HuBi 1 deben ser intrínsecamente más débiles. En particular HuBi 1 parece ser una nebulosa ionizada por una estrella de baja masa que evoluciona lentamente.

  8. A New Prescription for the Mass-loss Rates of WC and WO Stars

    Science.gov (United States)

    Tramper, F.; Sana, H.; de Koter, A.

    2016-12-01

    We present a new empirical prescription for the mass-loss rates of carbon- and oxygen-sequence Wolf-Rayet stars as a function of their luminosity, surface chemical composition, and initial metallicity. The new prescription is based on results of detailed spectral analyses of WC and WO stars and improves the often applied Nugis and Lamers relation. We find that the mass-loss rates of WC and WO stars (with X = 0 and Y ≲ 0.98) can be expressed as {log} \\dot{M}=-9.20+0.85{log}(L/L ⊙) + 0.44 log Y + 0.25 log (Z Fe/Z Fe,⊙). This relation is based on mass-loss determinations that assume a volume-filling factor of 0.1, but the prescription can easily be scaled to account for other volume-filling factors. The residual of the fit is σ = 0.06 dex. We investigated whether the relation can also describe the mass loss of hydrogen-free WN stars and showed that it can when an adjustment of the metallicity dependence ({log} \\dot{M}\\propto 1.3{log}({Z}{Fe}/{Z}{Fe,⊙ })) is applied. Compared to that of Nugis and Lamers, \\dot{M} is less sensitive to the luminosity and the surface abundance, implying a stronger mass loss of massive stars in their late stages of evolution. The modest metallicity dependence implies that if WC or WO stars are formed in metal-deficient environments, their mass-loss rates are higher than currently anticipated. These effects may result in the formation of a larger number of SNe Ic and fewer black holes and may favor the production of superluminous SNe Ic through interaction with C- and O-rich circumstellar material or dense stellar wind.

  9. Laser surface treatment of magnesium alloy with WC and TiC powders using HPDL

    Directory of Open Access Journals (Sweden)

    L.A. Dobrzański

    2008-06-01

    Full Text Available Purpose: The aim of this work was to improve the surface layer cast magnesium alloy EN-MCMgAl6Zn1 by laser surface treatment. The purpose of this work was also to determine the laser treatment parameter.Design/methodology/approach: The laser treatment of an EN-MCMgAl6Zn1 magnesium alloy with alloying WC and also TiC powders was carried out using a high power diode laser (HPDL. The resulting microstructure in the modified surface layer was examinated using scanning electron microscopy. Phase composition was determined by the X-ray diffraction method using the XPert device. The measurements of microhardness of the modified surface layer was also studied.Findings: The alloyed region has a fine microstructure with hard carbide particles. Microhardness of laser surface alloyed layer with both TiC and WC particles was significantly improved as compared to alloy without laser treatment.Research limitations/implications: In this research two powders (WC and TiC were used with the particle size over 5µm This investigation presents different speed rates feed by one process laser power.Practical implications: The results obtained in this investigation were promising to compared other conventional processes. High Power Diode Laser can be used as an economical substitute of Nd:YAG and CO2 to improve the surface magnesium alloy by feeding the carbide particles.Originality/value: The originality of this work is applying of High Power Diode Laser for alloying of magnesium alloy using hard particles like tungsten carbide and titanium carbide.

  10. Parametric study of an HVOF process for the deposition of nanostructured WC-Co coatings

    Science.gov (United States)

    Bartuli, Cecilia; Valente, Teodoro; Cipri, Fabio; Bemporad, Edoardo; Tului, Mario

    2005-06-01

    Nanocrystalline WC-Co coatings were deposited by high velocity oxyfuel from commercial nanostructured composite powders. Processing parameters were optimized for maximal retention of the nanocrystalline size and for minimal decarburation of the ceramic reinforcement. Thermochemical and gas-dynamical properties of gas and particle flows within the combustion flame were identified in various operating conditions by computational fluid-dynamics (CFD) simulation. Significant improvements of the mechanical properties of the coatings were obtained: a decrease of the friction coefficient was measured for the nanostructured coatings, together with an increase of microhardness and fracture toughness.

  11. TED-Ed lessons & TED-Ed clubs: Educational activities to amplify students' voices

    Science.gov (United States)

    Villias, Georgios

    2017-04-01

    TED-Ed lessons and TED-Ed clubs are two powerful educational tools that can be used in today's school classrooms in order to create an educational environment that is engaging for the students and favors their active participation, created and fostered by TED-Ed. TED-Ed is TED's educational initiative, committed to create lessons worth sharing and amplify the voices and ideas of teachers and students around the world. TED-Ed animated lessons are fully organized lessons structured around an animated video that introduces new topics to learners in an exciting, thought-provoking way. These lessons have been created as a result of the cooperation between expert educators and animators and have been uploaded at the TED-Ed platform (http://ed.ted.com). On the other hand, TED-Ed Clubs are also an interesting way to offer students the chance, the voice and the opportunity to express their thoughts, engage actively on these matters and connect with each other, both at a local, as well as at an international level (http://ed.ted.com/clubs). By developing new TED-Ed lessons or by customizing appropriately existing animated TED-Ed lessons (translating, modifying the questions asked, introducing new discussion topics), I have created and implemented in my student-centered, didactic approach, a series of TED-ED animated lessons directly connected with the Greek national science syllabus that were used to spark students curiosity and initiate a further analytical discussion or introduce other relevant educational activities (http://gvillias.wixsite.com/education). Furthermore, at my school, we established Varvakeio TED-Ed Club, an environment that supports and empowers our students to research, develop and disseminate their own personal ideas that worth spreading. During the year, our members were inspired by watching TED talks presented by experts on their field on various different areas, including social, economical, environmental and technological-scientific issues. Our aim

  12. Canadian EdGEO National Workshop Program

    Science.gov (United States)

    Clinton, L. A.; Haidl, F. M.; Hymers, L. A.; van der Flier-Keller, E.

    2009-05-01

    Established in the early 1970s, EdGEO supports locally driven geosciences workshops for Canadian teachers. Workshops are organized by geoscientists and teachers, and typically have field, laboratory and classroom components. Grants of up to $3000 per workshop are available from the National EdGEO Program. By providing educational opportunities for today's teachers and, through them, their students, EdGEO seeks to cultivate a heightened awareness of our planet. EdGEO workshops provide teachers with potential fieldtrip sites for their students and the knowledge, enthusiasm and materials to inspire their students to engage in geoscience. Networking opportunities with local experts promote the importance of the geoscience profession. The expected result is an improved capacity on the part of Canadians to understand the Earth and to make informed decisions, especially with regard to the use of mineral and energy resources, the maintenance and remediation of the environment, and response to geological hazards. There exists a critical need to provide teachers with training and resources to tackle their Earth science curricula. In 2008, EdGEO supported fourteen workshops, with an unprecedented 521 teachers attending. These teachers then used our resources to reach an estimated 14,000 students during that single academic year. EdGEO workshops are locally driven and are therefore very diverse. Workshops are strongly tied to the provincial curriculum, focus on a specific geoscience topic, or may be largely field-based to demonstrate and practice how field activities could be incorporated into Earth science teaching. Many strive to include all of these important components. Geoscientists and teachers work collaboratively to develop and deliver EdGEO workshops to ensure that the activities can be effectively used in the classroom. The length of these professional development opportunities range from two-hour sessions to several days, and can generally accommodate up to twenty

  13. Effects of WC-17Co Coating Combined with Shot Peening Treatment on Fatigue Behaviors of TC21 Titanium Alloy

    Directory of Open Access Journals (Sweden)

    Dongxing Du

    2016-10-01

    Full Text Available The improvement and mechanism of the fatigue resistance of TC21 high-strength titanium alloy with a high velocity oxygen fuel (HVOF sprayed WC-17Co coating was investigated. X-ray diffraction (XRD and the corresponding stress measurement instrument, a surface roughness tester, a micro-hardness tester, and a scanning electron microscope (SEM were used to determine the properties of the HVOF WC-17Co coating with or without shot peening. The fatigue behavior of the TC21 titanium alloy with or without the WC-17Co coating was determined by using a rotating bending fatigue testing machine. The results revealed that the polished HVOF sprayed WC-17Co coating had almost the same fatigue resistance as the TC21 titanium alloy substrate. This resulted from the polishing-induced residual surface compressive stress and a decrease in the stress concentration on the surface of the coating. Moderate-intensity shot peening of the polished WC-17Co coatings resulted in significant improvement of the fatigue resistance of the alloy. Furthermore, the fatigue life was substantially higher than that of the substrate, owing to the deep distribution of residual stress and high compressive stress induced by shot peening. The improved surface toughness of the coating can effectively delay the initiation of fatigue crack propagation.

  14. Corrosion Resistance of Ni-Based WC/Co Coatings Deposited by Spray and Fuse Process Varying the Oxygen Flow

    Science.gov (United States)

    Jiménez, H.; Olaya, J. J.; Alfonso, J. E.; Mtshali, C. B.; Pineda-Vargas, C. A.

    2017-08-01

    In this work, the effect of oxygen flow variation in the corrosion behavior of Ni-based WC/Co coatings deposited by spray and fuse process was investigated. The coatings were deposited on gray cast iron substrates using a Superjet Eutalloy thermal spraying gun. The morphology of the coatings was analyzed using scanning electron microscopy. The crystallographic phases were registered by x-ray diffraction (XRD), the diffraction patterns show the crystalline phases of the powder components with principal reflections for Ni and WC, the increase in flame temperature, due to the oxygen flow variation, generated amorphization in the nickel and an important crystallization of the planes (111) and (222) of WC as well as the decarburization of WC in W2C and W metallic. The corrosion behavior was investigated at room temperature in a 3.5% w/w aqueous solution of NaCl via potentiodynamic polarization. Electrochemical corrosion test showed that the coatings deposited under neutral flame conditions with an oxygen flow of 12.88 SCFH evidenced higher corrosion resistance. The chemical composition of the coatings and corrosion areas were analyzed by particle-induced x-ray emission, this technique permitting the corroboration of the decarburization process of WC determined by XRD and the formation of Cl structures.

  15. Friction Charateristics of WC-NiP Composites for Mechanical Seals when Matched with Stationary Ring Materials%WC-NiP合金密封材料与不同软材料组对时的摩擦性能

    Institute of Scientific and Technical Information of China (English)

    曾涛; 陈匡民

    1999-01-01

    对研究开发的一种机械密封新型摩擦副材料WC-NiP合金与不同软材料组对时的摩擦特性进行了研究.考察了在水润滑条件下WC-NiP/浸呋喃树脂石墨配对的摩擦性能,并分别与浸铜石墨、浸玻璃石墨和填充聚四氟乙烯配对作了对比.结果表明:WC-NiP合金作为硬环材料时,与之组对的软环材料为浸呋喃树脂石墨时其摩擦性能最优,并得出摩擦系数的关联式.

  16. CHEMICAL PRETREATMENTS OF THE SURFACE OF WC-15wt%Co WITH DIAMOND COATINGS

    Institute of Scientific and Technical Information of China (English)

    S. Liu; Z.M. Yu; D.Q. Yi; Y.X. Li

    2001-01-01

    Diamond films were deposited on the cemented carbide WC-15%Co substrates by a hot-filament chemical vapor deposition reactor. The substrate surfaces were chemically pretreated by the following two-step etching method: first using Murakami reagent for 1-3min, and second an HNO3:HCl=1:1 solution for 10-40min. It is indicated that the Co content of the substrate surfaces could be reduced from 15% to 0.81-6.04% within the etching depth of 5-10μm, the surface roughness of the substrates was increased up to Ra=1.0μm, and the substrates hardness was decreased from 89.0 HRA to 83.0HRA after the two-step etching. It is observed that the morphologies of the diamond films on the WC-15%Co substrates emerge in various shapes. The indentation testing shows that the good adhesion between diamond film and the substrate after HF CVD deposition could be obtained.

  17. Proceedings of the IASTED technology conferences : MS, CA, WC, EME, SOE 2010

    Energy Technology Data Exchange (ETDEWEB)

    Alhajj, R.S.; Leung, V.C.M.; Saif, M.; Thring, R. (eds.)

    2010-08-13

    This conference on energy and power systems provided a forum for electric power industry experts and international researchers to discuss the latest research and innovative technologies related to power system modelling and simulation (MS); control and applications (CA); wireless communications (WC); environment management and engineering (EME); and, solar energy (SOE). The MS theme was divided into tracks entitled: applications of modelling and simulation; data modelling; energy and power systems modelling; intelligent optimization and modelling; mathematical modelling; modelling and simulation methodologies; Monte Carlo simulation; virtual reality; and workflow management and probabilistic modelling. The CA theme was divided into tracks entitled: electric drive and energy systems; intelligent and robotic systems; time varying and time delay systems; control system design; engineering applications of control; and non-engineering applications of control. The WC theme was divided into tracks entitled: wireless communications; wireless networks; and cognitive radio networks and systems. The EME theme was divided into tracks entitled: natural resources management; environmental impact assessment; land management; and waste management. The final track of the conference was on solar energy. The conference featured 143 presentations, of which 24 have been catalogued separately for inclusion in this database. refs., tabs., figs.

  18. Oxidation performance of Fe-Al/WC composite coatings produced by high velocity arc spraying

    Institute of Scientific and Technical Information of China (English)

    MENG Fan-jun; XU Bin-shi; ZHU Sheng; MA Shi-ning; ZHANG wei

    2005-01-01

    Fe-Al intermetallics with remarkable high-temperature intensity and excellent erosion, high-temperature oxidation and sulfuration resistance are potential low cost high-temperature structural materials. But the room tem perature brittleness induces shape difficult and limits its industrial application. The Fe-Al intermetallic coatings were prepared by high velocity arc spraying technology with cored wire on 20G steel, which will not only obviate the problems faced in fabrication of these alloys into useful shapes, but also allow the effective use of their outstanding high-temperature performance. The Fe-Al/WC intermetallic composite coatings were prepared by high velocity arc spraying technology on 20G steel and the oxidation performance of Fe-Al/WC composite coatings was studied by means of thermogrativmetic analyzer at 450, 650 and 800 ℃. The results demonstrate that the kinetics curve of oxidation at three temperatures approximately follows the logarithmic law. The composition of the oxidized coating is mainly composed of Al2 O3, Fe2 O3, Fe3 O4 and FeO. These phases distribute unevenly. The protective Al2 O3 film firstly forms and preserves the coatings from further oxidation.

  19. Arecibo and Goldstone Radar Imaging of Near-Earth Asteroid 2005 WC1

    Science.gov (United States)

    Lawrence, Kenneth J.; Benner, Lance A. M.; Brozovic, Marina; Jao, Joseph S.; Giorgini, Jon D.; Slade, Martin A.; Jurgens, Raymond F.; Nolan, Michael C.; Howell, Ellen S.; Taylor, Patrick A.

    2016-10-01

    We report radar observations of near-Earth asteroid 2005 WC1 that were obtained at Arecibo (2380 MHz, 13 cm) and Goldstone (8560 MHz, 3.5 cm) on 2005 December 14-15 during the asteroid's approach within 0.020 au (7.7 lunar distances). The asteroid was a strong radar target and we obtained a sequence of delay-Doppler images with resolutions as fine as 7.5 m/pixel. The radar images reveal an angular object with several pronounced facets, radar-dark regions, and an estimated diameter of ~0.4 km. The rotation of the facets in the images gives a rotation period of 2.57 h that is consistent with the estimate of 2.582 h ± 0.002 h reported by Miles et al. (private communication). 2005 WC1 has a circular polarization ratio of 1.12 ± 0.02 that is one of the highest values known, suggesting a structurally-complex near-surface at centimeter decimeter spatial scales. This work has been performed at the Jet Propulsion Laboratory, California Institute of Technology, under contract with NASA.

  20. A new prescription for the mass-loss rates of WC and WO stars

    CERN Document Server

    Tramper, F; de Koter, A

    2016-01-01

    We present a new empirical prescription for the mass-loss rates of carbon and oxygen sequence Wolf-Rayet stars as a function of their luminosity, surface chemical composition, and initial metallicity. The new prescription is based on results of detailed spectral analyses of WC and WO stars, and improves the often applied Nugis & Lamers (2000) relation. We find that the mass-loss rates of WC and WO stars (with $X=0$ and $Y < 0.98$) can be expressed as $\\log{\\dot{M}} = -9.20 + 0.85\\log{(L/L_{\\odot})} + 0.44\\log{Y} + 0.25\\log{(Z_{\\mathrm{Fe}}/Z_{\\mathrm{Fe}, \\odot})}$. This relation is based on mass-loss determinations that assume a volume-filling factor of 0.1, but the prescription can easily be scaled to account for other volume-filling factors. The residual of the fit is $\\sigma = 0.06$ dex. We investigated whether the relation can also describe the mass loss of hydrogen-free WN stars and showed that it can when an adjustement of the metallicty dependence ($\\log{\\dot{M}} \\propto 1.3\\log{(Z_{\\mathrm{Fe}...

  1. High-pressure shock behavior of WC and Ta2O5 powders.

    Energy Technology Data Exchange (ETDEWEB)

    Knudson, Marcus D. (Sandia National Laboratories, Albuquerque, NM); Reinhart, William Dodd (Sandia National Laboratories, Albuquerque, NM); Vogler, Tracy John; Root, Seth (Sandia National Laboratories, Albuquerque, NM)

    2011-10-01

    Planar shock experiments were conducted on granular tungsten carbide (WC) and tantalum oxide (Ta{sub 2}O{sub 5}) using the Z machine and a 2-stage gas gun. Additional shock experiments were also conducted on a nearly fully dense form of Ta{sub 2}O{sub 5}. The experiments on WC yield some of the highest pressure results for granular materials obtained to date. Because of the high distention of Ta{sub 2}O{sub 5}, the pressures obtained were significantly lower, but the very high temperatures generated led to large contributions of thermal energy to the material response. These experiments demonstrate that the Z machine can be used to obtain accurate shock data on granular materials. The data on Ta{sub 2}O{sub 5} were utilized in making improvements to the P-{lambda} model for high pressures; the model is found to capture the results not only of the Z and gas gun experiments but also those from laser experiments on low density aerogels. The results are also used to illustrate an approach for generating an equation of state using only the limited data coming from nanoindentation. Although the EOS generated in this manner is rather simplistic, for this material it gives reasonably good results.

  2. The Formation of Nanocrystalline Diamond Coating on WC Deposited by Microwave Assisted Plasma CVD

    Science.gov (United States)

    Toff, M. R. M.; Hamzah, E.; Purniawan, A.

    2010-03-01

    Diamond is one form of carbon structure. The extreme hardness and high chemical resistant of diamond coatings determined that many works on this area relate to coated materials for tribological applications in biomedicine, as mechanical seals or cutting tools for hard machining operations. In the work, nanocrystalline diamond (NCD) coated tungsten carbide (WC) have been deposited by microwave assisted plasma chemical vapor deposition (MAPCVD) from CH4/H2 mixtures. Morphology of NCD was investigated by using Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM). The quality of NCD is defined as ratio between diamond and non diamond and also full width at half maximum (FWHM) was determined using Raman spectra. The result found that the NCD structure can be deposited on WC surface using CH4/H2 gas mixture with grain size ˜20 nm to 100 nm. Increase %CH4 concentration due to increase the nucleation of NCD whereas decrease the quality of diamond. Based on Raman spectra, the quality of NCD is in the range ˜98.82-99.01% and 99.56-99.75% for NCD and microcrystalline (MCD), respectively. In addition, FWHM of NCD is high than MCD in the range of 8.664-62.24 cm-1 and 4.24-5.05 cm-1 for NCD and MCD respectively that indicate the crystallineity of NCD is smaller than MCD.

  3. Modification Performance of WC Nanoparticles in Aluminum and an Al-Si Casting Alloy

    Science.gov (United States)

    Borodianskiy, Konstantin; Zinigrad, Michael

    2016-04-01

    The influence of a modifier based on tungsten carbide (WC) nanoparticles is investigated first using 1 kg of bulk aluminum and then in a real industrial process using a commercial Al-Si casting alloy. The modifier is prepared by two different approaches, and its influence is investigated in pure aluminum and in commercial aluminum alloy A356. Microstructural studies show that the mean grain size in pure aluminum is reduced by 11.5 pct. Such a change usually causes an improvement in the mechanical properties of metals. Accordingly, the mechanical properties of the A356 alloy modified with WC nanoparticles are determined after T6 heat treatment and compared with unmodified specimens of the same alloy. The results obtained in the modified A356 alloy reveal unusual behavior of the mechanical properties, where the elongation of the alloys improved by 32 to 64 pct, while the tensile strength and yield strength remained unchanged. This behavior is attributable to a grain-size strengthening mechanism, where strengthening occurs due to the high concentration of grain boundaries, which act as obstacles to the motion of dislocations in the lattice.

  4. Facile Route to Prepare TaC,NbC and WC Nanoparticles

    Institute of Scientific and Technical Information of China (English)

    DU Yinxiao; LEI Ming; YANG Hui; WANG Xuefei

    2008-01-01

    By a novel solid-state reaction process using amorphous C3N4 (a-C3N4) and transition metal oxides as starting reagents,cubic TaC,NbC and hexagonal WC nanoparticles were successfully synthesized at 1150 ℃.The products were characterized by power X-ray diffraction (XRD),field-emission scanning electron microscope (FE-SEM),energy-dispersive X-ray spectroscopy (EDX),transmission electron microscopy (TEM) and high-resolution TEM (HRTEM).The experimental resuits show that a-C3N4 obtained by the reaction between C3N3Cl3 and Li3N is a highly efficient carburation reagent and the transition metal oxides are completely transformed into the corresponding metal carbide nanoparticles at 1150 ℃,respectively,which is significantly lower than that reported for the traditional preparation of carbides,typically> 1600 ℃.The TaC,NbC and WC nanoparticles are found to have an average particle size of 10 nm,15 nm and 8 nm by TEM observation,respectively.

  5. Optimization of Ni-Based WC/Co/Cr Composite Coatings Produced by Multilayer Laser Cladding

    Directory of Open Access Journals (Sweden)

    Andrea Angelastro

    2013-01-01

    Full Text Available As a surface coating technique, laser cladding (LC has been developed for improving wear, corrosion, and fatigue properties of mechanical components. The main advantage of this process is the capability of introducing hard particles such as SiC, TiC, and WC as reinforcements in the metallic matrix such as Ni-based alloy, Co-based alloy, and Fe-based alloy to form ceramic-metal composite coatings, which have very high hardness and good wear resistance. In this paper, Ni-based alloy (Colmonoy 227-F and Tungsten Carbides/Cobalt/Chromium (WC/Co/Cr composite coatings were fabricated by the multilayer laser cladding technique (MLC. An optimization procedure was implemented to obtain the combination of process parameters that minimizes the porosity and produces good adhesion to a stainless steel substrate. The optimization procedure was worked out with a mathematical model that was supported by an experimental analysis, which studied the shape of the clad track generated by melting coaxially fed powders with a laser. Microstructural and microhardness analysis completed the set of test performed on the coatings.

  6. Preparing WC-Co Composite Powder by Co-precipitation and Direct Carbonized In-situ Synthesized Method%共沉淀-直接碳化原位合成WC-Co复合粉的研究

    Institute of Scientific and Technical Information of China (English)

    王玉香; 文小强; 周健; 袁德林; 郭春平

    2016-01-01

    Using ammonium metatungstate, cobalt nitrate, ammonium hydroxide, and carbon black as the raw materials, the WC-Co composite powder was produced by co-precipitation and direct carbonized in-situ synthesized method. The synthesis process of precursor and effects of reduction carbonization process parameters on phase of product were studied. The powder morphology, phase compositions of WC-Co composite powder were characterized by SEM, XRD, and the reduction carbonization process was studied. The results show that each precursor powder has some larger particles, which make up by lots of minute particles, and the diameter is about 500 nm. Precursor powders are carbonized completely at 1000℃, then prepared composite powder has WC and Co phases, which have good dispersion and uniform distribution.%以偏钨酸铵、硝酸钴、氨水、炭黑为原材料,采用共沉淀-直接碳化原位合成法制备了WC-Co复合粉.研究了前驱体的制备过程,考察了还原碳化工艺参数对所得产物物相的影响.利用SEM、XRD分析方法对粉末样品的微观形貌和物相组成进行了表征,并对还原碳化过程进行了探讨.结果表明:采用共沉淀法制备的前驱体粉末为许多小颗粒团聚而成的大颗粒,小颗粒均匀细小,粒径在500 nm左右,前驱体粉末经1000℃还原碳化可以得到物相纯净的WC-Co复合粉,WC-Co复合粉分散性好,粒度分布均匀.

  7. Ed Deutschman Visit Images, May 2, 2011

    OpenAIRE

    Deutschman, Ed

    2011-01-01

    Background: Ed Deutschman was a Navy cadet at the Del Monte Pre-Flight School, located at the now (2013) Naval Postgraduate School. Mr Deutschman visited the Dudley Knox Library on May 2, 2011, and spoke about his service in World War II as a Corsair fighter pilot in the Pacific.

  8. Prospective study of violence against ED workers.

    Science.gov (United States)

    Kowalenko, Terry; Gates, Donna; Gillespie, Gordon Lee; Succop, Paul; Mentzel, Tammy K

    2013-01-01

    Health care support occupations have an assault-injury rate nearly 10 times the general sector. Emergency departments (EDs) are at greatest risk of such events. The objective was to describe the incidence of violence in ED health care workers (HCWs) over 9 months. Specific aims were to (1) identify demographic, occupational, and perpetrator factors related to violent events (VEs) and (2) identify predictors of acute stress in victims and predictors of loss of productivity. A longitudinal, repeated-methods design was used to collect monthly survey data from ED HCWs at 6 hospitals. Surveys assessed number and type of VEs, and feelings of safety and confidence. Victims also completed specific VE surveys. Descriptive statistics and a repeated-measure linear regression model were used. Two hundred thirteen ED HCWs completed 1795 monthly surveys and 827 VEs were reported. Average VE rate per person per 9 months was 4.15. Six hundred one events were physical threats (PTs) (3.01 per person). Two hundred twenty six events were assaults (1.13 per person). Five hundred one VE surveys were completed, describing 341 PTs and 160 assaults. Men perpetrated 63% of PTs and 52% of assaults. Significant differences in VEs were reported between registered nurses (RNs) and medical doctors (MDs) (P = .0017) and patient care assistants (P stress than the MDs (P stress reduced productivity (P stress, and lost productivity. Acute stress has negative consequences on workers' ability to perform their duties. Copyright © 2013 Elsevier Inc. All rights reserved.

  9. Desempeño de insertos de WC recubiertos con nanomulticapas de [TiN/TiAlN]n en el mecanizado del acero endurecido AISI 4340

    Directory of Open Access Journals (Sweden)

    Luis Henry Moreno

    2011-01-01

    Full Text Available En el presente trabajo se muestran los resultados de la resistencia al desgaste de insertos de carburo de tungsteno (WC sin recubrir y recubiertos con multinanocapas de [TiN/TiAlN]n con un espesor total promedio del recubrimiento de 4 ¿m, así como de insertos recubiertos con monocapas comerciales de TiCN-Al2O3-TiN (TINAL. Se realizaron ensayos de vida útil, análisis de temperatura en la zona de corte, mediciones de rugosidad superfi cial sobre la pieza y sobre los insertos en la superfi cie de ataque, análisis de huella de contacto entre viruta-insertos y análisis de composición química (EDS. Los ensayos se realizaron sobre piezas de acero AISI 4340 utilizando régimen de corte de acabado y aplicando altas velocidades de corte (HSC. Los resultados de mecanizado de acero, para un recorrido de 8.000 metros con diferentes insertos de carburo de tungsteno (WC, sin recubrimiento y recubiertos presentaron valores de desgaste de 0,117 mm y 0,138 mm; en relación a los insertos recubiertos con 300 y 200 bicapas de TiN/TiAlN, respectivamente. De igual manera, los insertos recubiertos con TINAL exhibieron valores de desgaste de 0,174 mm. Además, los valores de temperatura en la zona de corte y para una velocidad de corte de 176,6 m/mim fueron de 522,6 oC para los recubrimientos con 300 bicapas, de 721,4 oC para aquellos con 200 bicapas, y de 1.327,6 oC para los insertos recubiertos con TINAL. La disminución de la temperatura en la zona de corte, relacionada con un menor coefi ciente de fricción y una menor fuerza de corte, contribuyeron al alargamiento de la vida útil de los insertos.

  10. Personality, Cortisol, and Cognition in Non-demented Elderly Subjects: Results from a Population-Based Study

    Science.gov (United States)

    Ouanes, Sami; Castelao, Enrique; von Gunten, Armin; Vidal, Pedro M.; Preisig, Martin; Popp, Julius

    2017-01-01

    Certain personality traits, in particular higher neuroticism, have been associated, on one hand, with elevated cortisol levels, and on the other hand, with poorer cognitive performance. At the same time, several studies highlighted the association between high cortisol and poor cognitive functioning. Here, we hypothesized that increased cortisol may be associated with poorer cognition and with certain personality traits (mainly high neuroticism), and that personality might explain the association between cortisol and cognition. A cross-sectional analysis was conducted using data from Colaus/PsyColaus, a population-based study involving residents of Lausanne, Switzerland. Salivary cortisol samples (upon waking, 30 min after waking, at 11 am and at 8 pm) along with cognitive and personality measures were obtained from 643 non-demented participants aged at least 65. Personality traits were assessed using the NEO Five-Factor Inventory (NEO-FFI). We examined the links between the cortisol Area under the Curve (AUC), the Clinical Dementia Rating Sum of Boxes (CDRSOB) and the NEO-FFI scores. No association was found between personality traits and the CDRSOB or the MMSE score, controlling for age, sex, depression, education and BMI. However, the executive functioning domain z-score was negatively associated with agreeableness (p = 0.005; slope = -0.107 [-0.181; -0.033]) and openness (p = 0.029; slope = -0.081 [-0.154; -0.008]) after controlling for age, sex, depression, education and BMI. The CDRSOB score was positively associated with the cortisol AUC after controlling for age, sex, BMI, education and depression, (p = 0.003; slope = 0.686 [0.240; 1.333]). This association remained significant after controlling for personality traits and for the interaction between personality traits and the cortisol AUC (p = 0.006; slope = 0.792 [0.233; 1.352]. High agreeableness and openness might be associated with poorer executive performance in later life. Increased cortisol may be

  11. Personality, Cortisol, and Cognition in Non-demented Elderly Subjects: Results from a Population-Based Study.

    Science.gov (United States)

    Ouanes, Sami; Castelao, Enrique; von Gunten, Armin; Vidal, Pedro M; Preisig, Martin; Popp, Julius

    2017-01-01

    Certain personality traits, in particular higher neuroticism, have been associated, on one hand, with elevated cortisol levels, and on the other hand, with poorer cognitive performance. At the same time, several studies highlighted the association between high cortisol and poor cognitive functioning. Here, we hypothesized that increased cortisol may be associated with poorer cognition and with certain personality traits (mainly high neuroticism), and that personality might explain the association between cortisol and cognition. A cross-sectional analysis was conducted using data from Colaus/PsyColaus, a population-based study involving residents of Lausanne, Switzerland. Salivary cortisol samples (upon waking, 30 min after waking, at 11 am and at 8 pm) along with cognitive and personality measures were obtained from 643 non-demented participants aged at least 65. Personality traits were assessed using the NEO Five-Factor Inventory (NEO-FFI). We examined the links between the cortisol Area under the Curve (AUC), the Clinical Dementia Rating Sum of Boxes (CDRSOB) and the NEO-FFI scores. No association was found between personality traits and the CDRSOB or the MMSE score, controlling for age, sex, depression, education and BMI. However, the executive functioning domain z-score was negatively associated with agreeableness (p = 0.005; slope = -0.107 [-0.181; -0.033]) and openness (p = 0.029; slope = -0.081 [-0.154; -0.008]) after controlling for age, sex, depression, education and BMI. The CDRSOB score was positively associated with the cortisol AUC after controlling for age, sex, BMI, education and depression, (p = 0.003; slope = 0.686 [0.240; 1.333]). This association remained significant after controlling for personality traits and for the interaction between personality traits and the cortisol AUC (p = 0.006; slope = 0.792 [0.233; 1.352]. High agreeableness and openness might be associated with poorer executive performance in later life. Increased cortisol may be

  12. The friction coefficient evolution of a MoS2/WC multi-layer coating system during sliding wear

    Science.gov (United States)

    Chan, T. Y.; Hu, Y.; Gharbi, Mohammad M.; Politis, D. J.; Wang, L.

    2016-08-01

    This paper discusses the evolution of friction coefficient for the multi-layered Molybdenum Disulphide (MoS2) and WC coated substrate during sliding against Aluminium AA 6082 material. A soft MoS2 coating was prepared over a hard WC coated G3500 cast iron tool substrate and underwent friction test using a pin-on-disc tribometer. The lifetime of the coating was reduced with increasing load while the Aluminium debris accumulated on the WC hard coating surfaces, accelerated the breakdown of the coatings. The lifetime of the coating was represented by the friction coefficient and the sliding distance before MoS2 coating breakdown and was found to be affected by the load applied and the wear mechanism.

  13. Wear resistance of WC/Co HVOF-coatings and galvanic Cr coatings modified by diamond nanoparticles

    Science.gov (United States)

    Kandeva, M.; Grozdanova, T.; Karastoyanov, D.; Assenova, E.

    2017-02-01

    The efforts in the recent 20 years are related to search of ecological solutions in the tribotechnologies for the replacement of galvanic Cr coatings in the contact systems operating under extreme conditions: abrasion, erosion, cavitation, corrosion, shock and vibration loads. One of the solutions is in the composite coatings deposited by high velocity gas-flame process (HVOF). The present paper presents comparative study results for mechanical and tribological characteristics of galvanic Cr coatings without nanoparticles, galvanic Cr coatings modified by diamond nanoparticles NDDS of various concentration 0.6; 10; 15 и 20% obtained under three technological regimes, and composite WC-12Co coating. Comparative results about hardness, wear, wear resistance and friction coefficient are obtained for galvanic Cr-NDDS and WC-12Co coatings operating at equal friction conditions of dry friction on abrasive surface. The WC-12Co coating shows 5.4 to 7 times higher wear resistance compared to the galvanic Cr-NDDS coatings.

  14. COBRA-WC: a version of COBRA for single-phase multiassembly thermal hydraulic transient analysis. [LMFBR

    Energy Technology Data Exchange (ETDEWEB)

    George, T.L.; Basehore, K.L.; Wheeler, C.L.; Prather, W.A.; Masterson, R.E.

    1980-07-01

    The objective of this report is to provide the user of the COBRA-WC (Whole Core) code a basic understanding of the code operation and capabilities. Included in this manual are the equations solved and the assumptions made in their derivations, a general description of the code capabilities, an explanation of the numerical algorithms used to solve the equations, and input instructions for using the code. Also, the auxiliary programs GEOM and SPECSET are described and input instructions for each are given. Input for COBRA-WC sample problems and the corresponding output are given in the appendices. The COBRA-WC code has been developed from the COBRA-IV-I code to analyze liquid Metal Fast Breeder Reactor (LMFBR) assembly transients. It was specifically developed to analyze a core flow coastdown to natural circulation cooling.

  15. Free energies of formation of WC and WzC and the thermodynamic properties of carbon in solid tungsten

    Science.gov (United States)

    Gupta, D. K.; Seigle, L. L.

    1974-01-01

    The activity of carbon in the two-phase regions - W + WC and W + W2C was obtained from the carbon content of iron rods equilibrated with mixtures of metal plus carbide powders. From this activity data the standard free energies of formation of WC and W2C were calculated. The temperature of the invariant reaction W2C = W + WC was fixed at 1570 + or - 5K. Using available solubility data for C in solid W, the partial molar free energy of C in the dilute solid solution was also calculated. The heat of solution of C in W, and the excess entropy for the interstitial solid solution, were computed, assuming that the carbon atoms reside in the octahedral interstices of bcc W.

  16. Oxidation behavior of HVOF-sprayed nanostructured and CeO2-modified WC-12Co coatings

    Science.gov (United States)

    Xi, Naiyuan; Hang, Zongqiu; Liu, Yan; Chen, Hui; Zhang, Mingyue; Gao, Wei

    2017-07-01

    Two types of WC-12Co coatings with different modifications were deposited on steel substrates using high velocity oxygen fuel (HVOF) spraying. The coated samples were oxidized at 550∘C and 650∘C in ambient atmosphere. Oxidation mass gain was measured by electronic balance. Phase composition and microstructure evolution of both coatings after oxidation were conducted by X-ray diffraction (XRD) and scanning electron microscopy (SEM). Microhardness testing was performed before and after oxidation testing. The results showed that at 550∘C and 650∘C, the rare-earth modified WC-12Co coating has lower oxidation rates compared with the nanostructured WC-12Co coating. This might be due to the rare-earth modification coating reducing the porosity and oxygen diffusion in the coatings, therefore delaying the crack formation and propagation.

  17. Structural and interfacial analysis of WC92-Co8 coating deposited on titanium alloy by electrospark deposition

    Energy Technology Data Exchange (ETDEWEB)

    Wang, R.J.; Qian, Y.Y.; Liu, J

    2004-04-30

    Electrospark deposition (ESD) is a promising process to produce hard and wear-resisting coatings on metallic substrates. In this paper, microstructure and interfacial characteristics of the WC92-Co8 coated-titanium are presented. A metallurgical bonding between the coating and substrate is obtained. The Ti element was found to distribute in WC92-Co8 at the metal pool, as well as the interface by diffusion. Some new phases were produced in the coating layer due to the chemical reaction during the ESD process. Experimental observation and thermodynamic analysis were utilized to study the mechanism of ESD.

  18. Structural and interfacial analysis of WC92 Co8 coating deposited on titanium alloy by electrospark deposition

    Science.gov (United States)

    Wang, R. J.; Qian, Y. Y.; Liu, J.

    2004-04-01

    Electrospark deposition (ESD) is a promising process to produce hard and wear-resisting coatings on metallic substrates. In this paper, microstructure and interfacial characteristics of the WC92-Co8 coated-titanium are presented. A metallurgical bonding between the coating and substrate is obtained. The Ti element was found to distribute in WC92-Co8 at the metal pool, as well as the interface by diffusion. Some new phases were produced in the coating layer due to the chemical reaction during the ESD process. Experimental observation and thermodynamic analysis were utilized to study the mechanism of ESD.

  19. A new photolithographic technique to detect the local deformation of materials: application to WC-Co composites

    Energy Technology Data Exchange (ETDEWEB)

    Mari, D. (Inst. de Genie Atomique, EPFL, Lausanne (Switzerland)); Marti, U.; Silva, P.C. (Inst. de Micro-Optoelectronique, EPFL, Lausanne (Switzerland))

    1992-11-01

    A new photolithographic technique is developed to visualize the deformation of composite materials at high temperature. A very fine metallic grid is deposited onto the surface of the samples. The grid is deposited by the evaporation of a metal through a mask fabricated by holographic lithography. This process provides a means of obtaining grids with a separation of lines as fine as 0.1 [mu]m. Samples of WC-Co composite material were deformed at 900degC and observed by scanning electron microscopy. The displacement of the grid lines shows the decohesion of WC grains and sliding. No deformation inside the grains was observed. (orig.).

  20. Microstructure Evolution and Its Effect on the Wear Performance of HVOF-Sprayed Conventional WC-Co Coating

    Science.gov (United States)

    Fu, Dingfa; Xiong, Haoqi; Wang, Qun

    2016-10-01

    In this work, a conventional tungsten carbide 12% cobalt (WC-12Co) coating was deposited by using a liquid fuel JP-8000 high velocity oxyfuel spray system. The properties of the coating namely phase content, microstructure, hardness, porosity, and fracture toughness were examined. The microstructure evolution and its influence on the abrasive wear behavior of the coatings were evaluated in detail by in-situ scanning electron microscopy and a comprehensive model for decarburization of WC has been established using x-ray diffraction and transmission electron microscopy analyses.

  1. The Association between High Neuroticism-Low Extraversion and Dual-Task Performance during Walking While Talking in Non-demented Older Adults.

    Science.gov (United States)

    LeMonda, Brittany C; Mahoney, Jeannette R; Verghese, Joe; Holtzer, Roee

    2015-08-01

    The Walking While Talking (WWT) dual-task paradigm is a mobility stress test that predicts major outcomes, including falls, frailty, disability, and mortality in aging. Certain personality traits, such as neuroticism, extraversion, and their combination, have been linked to both cognitive and motor outcomes. We examined whether individual differences in personality dimensions of neuroticism and extraversion predicted dual-task performance decrements (both motor and cognitive) on a WWT task in non-demented older adults. We hypothesized that the combined effect of high neuroticism-low extraversion would be related to greater dual-task costs in gait velocity and cognitive performance in non-demented older adults. Participants (N=295; age range,=65-95 years; female=164) completed the Big Five Inventory and WWT task involving concurrent gait and a serial 7's subtraction task. Gait velocity was obtained using an instrumented walkway. The high neuroticism-low extraversion group incurred greater dual-task costs (i.e., worse performance) in both gait velocity {95% confidence interval (CI) [-17.68 to -3.07]} and cognitive performance (95% CI [-19.34 to -2.44]) compared to the low neuroticism-high extraversion group, suggesting that high neuroticism-low extraversion interferes with the allocation of attentional resources to competing task demands during the WWT task. Older individuals with high neuroticism-low extraversion may be at higher risk for falls, mobility decline and other adverse outcomes in aging.

  2. Cytoplasmic Streaming - Skylab Student Experiment ED-63

    Science.gov (United States)

    1973-01-01

    This chart describes the Skylab student experiment (ED-63), Cytoplasmic Streaming, proposed by Cheryl A. Peitz of Arapahoe High School, Littleton, Colorado. Experiment ED-63 was to observe the effect of zero-gravity on cytoplasmic streaming in the aquatic plant named Elodea, commonly called water weed or water thyme. The phenomenon of cytoplasmic streaming is not well understood, but it is recognized as the circulation mechanism of the internal materials or cytoplasm of a cell. Cytoplasm is a gelatinous substance that has the ability to change its viscosity and flow, carrying various cell materials with it. The activity can be stimulated by sunlight or heat. In March 1972, NASA and the National Science Teachers Association selected 25 experiment proposals for flight on Skylab. Science advisors from the Marshall Space Flight Center aided and assisted the students in developing the proposals for flight on Skylab.

  3. Pulse Electrodeposition for WC-Co-Ni Coating Preparation and Performance%脉冲电沉积WC-Co-Ni镀层的制备及性能研究

    Institute of Scientific and Technical Information of China (English)

    常季; 陈吉; 崔霄; 孙彦伟

    2015-01-01

    目的 提高WC-Co-Ni纳米晶复合镀层的综合性能. 方法 利用脉冲电沉积法制备WC-Co-Ni纳米晶复合镀层,分析镀层的结构、表面形貌及元素成分,测试镀层的显微硬度. 对WC-Co-Ni纳米晶复合镀层和304不锈钢进行5%(质量分数) H2 SO4 溶液浸泡实验,计算腐蚀速率,对比其耐蚀性. 结果 当脉冲参数为阴极电流密度5 A/dm2、脉冲占空比50%、脉冲频率2000 Hz时,施镀2 h制备的WC-Co-Ni复合镀层为纳米晶结构. 镀层表面平整、光亮,无裂纹,由立方晶型的Ni、六方结构的WC和立方晶型的Co组成,WC-Co颗粒均匀弥散在纳米晶Ni镀层内,且m( Ni) : m( W) : m( C) : m( Co)=6 : 2 : 1 : 1. WC-Co纳米颗粒起到了促进形核的作用,晶粒尺寸大多分布在20 nm左右. WC-Co纳米颗粒对镀层起到了弥散强化作用,使复合镀层的显微硬度达到600 HV. 在浸泡腐蚀实验中,随着温度从20 ℃升高至80 ℃,复合镀层的腐蚀速率增加缓慢,20 ℃下的腐蚀速率仅为0. 4192 mm/a,80 ℃下的腐蚀速率也低于20 mm/a.结论 脉冲电沉积法制备的WC-Co-Ni纳米晶复合镀层硬度高于传统的不锈钢材料,耐蚀性也优于304不锈钢,综合性能较好.%Objective To improve the comprehensive performance of WC-Co-Ni nanocrystalline composite coatings. Methods WC-Co-Ni nanocrystalline composite coatings were prepared by pulse electrodeposition, the structure, the surface morphology and the elemental composition were analyzed, microhardness of the composite coatings was tested. The 304 stainless steel and the com- posite coatings were immersed in H2 SO4 solution of the mass fraction of 5%, the corrosion rate was calculated and their corrosion resistances were compared. Results It was showed that when the pulse parameters were the follows, i. e. , 5 A/dm2 cathodic cur-rent density, pulse duty ratio 50%, the pulse frequency of 2000 Hz and the plating time 2 hours, the prepared WC-Co-Ni compos-ite coating formed a

  4. Case Study:EDS in China

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    @@ Asign that China is quickly moving up the global service outsourcing ranking came earlier this year when EDS (Electronic Data Services), one of the world's leading IT outsourcing companies,announced it would be moving its Asia headquarters to Shanghai from Australia. Recognizing the growing potential of China in this area, the company also announced it would shortly be launching at least two offshore software development centers in the country, with the first location due to be announced at the begining of November.

  5. Regional Energy Deployment System (ReEDS)

    Energy Technology Data Exchange (ETDEWEB)

    Short, W.; Sullivan, P.; Mai, T.; Mowers, M.; Uriarte, C.; Blair, N.; Heimiller, D.; Martinez, A.

    2011-12-01

    The Regional Energy Deployment System (ReEDS) is a deterministic optimization model of the deployment of electric power generation technologies and transmission infrastructure throughout the contiguous United States into the future. The model, developed by the National Renewable Energy Laboratory's Strategic Energy Analysis Center, is designed to analyze the critical energy issues in the electric sector, especially with respect to potential energy policies, such as clean energy and renewable energy standards or carbon restrictions. ReEDS provides a detailed treatment of electricity-generating and electrical storage technologies and specifically addresses a variety of issues related to renewable energy technologies, including accessibility and cost of transmission, regional quality of renewable resources, seasonal and diurnal generation profiles, variability of wind and solar power, and the influence of variability on the reliability of the electrical grid. ReEDS addresses these issues through a highly discretized regional structure, explicit statistical treatment of the variability in wind and solar output over time, and consideration of ancillary services' requirements and costs.

  6. Effects of particle density on depositing properties of WC-1 7 Co by HVOF process

    Institute of Scientific and Technical Information of China (English)

    丁坤英; 王立君

    2014-01-01

    The in-flight and deposition properties ofthree types ofWC-1 7 Co powder with different particle densities during a high-velocity oxygen fuel (HVOF)thermal spray process were investigated.Three types ofpowder exhibited similar velocity upon impact on the substrate surface.The powder with the lower particle density exhibited a higher temperature upon impingement process,resulting in the generation ofa higher flattening ratio.Thus,the coating derived from the powder with the lower particle density possessed superior micro-hardness,porosity and surface roughness.However,the coating with the lowest particle density showed the poorest fracture toughness because ofthe generation ofthe largest amount ofamorphous phase.

  7. Crystal orientation mapping applied to the Y-TZP/WC composite

    CERN Document Server

    Faryna, M; Sztwiertnia, K

    2002-01-01

    Crystal orientation measurements made by electron backscattered diffraction (EBSD) in the scanning electron microscope (SEM) and microscopic observations provided the basis for a quantitative investigation of microstructure in an yttria stabilized, tetragonal zirconia-based (Y-TZP) composite. Automatic crystal orientation mapping (ACOM) in a SEM can be preferable to transmission electron microscopy (TEM) for microstructural characterization, since no sample thinning is required, extensive crystal data is already available, and the analysis area is greatly increased. A composite with a 20 vol.% tungsten carbide (WC) content was chosen since it revealed crystal relationships between the matrix and carbide phase already established by TEM analysis. However, this composite was difficult to investigate in the EBSD/ SEM since it is non-conductive, the Y-TZP grain size is of the order of the system resolution, and the sample surface, though carefully prepared, reveals a distinctive microtopography. In this paper, so...

  8. Machinability of Al-SiC metal matrix composites using WC, PCD and MCD inserts

    Energy Technology Data Exchange (ETDEWEB)

    Beristain, J.; Gonzalo, O.; Sanda, A.

    2014-04-01

    The aim of this work is the study of the machinability of aluminium-silicon carbide Metal Matrix Composites (MMC) in turning operations. The cutting tools used were hard metal (WC) with and without coating, different grades and geometries of Poly-Crystalline Diamond (PCD) and Mono-Crystalline Diamond (MCD). The work piece material was AMC225xe, composed of aluminium-copper alloy AA 2124 and 25% wt of SiC, being the size of the SiC particles around 3 {mu}m. Experiments were conducted at various cutting speeds and cutting parameters in facing finishing operations, measuring the surface roughness, cutting forces and tool wear. The worn surface of the cutting tool was examined by Scanning Electron Microscope (SEM). It was observed that the Built Up Edge (BUE) and stuck material is higher in the MCD tools than in the PCD tools. The BUE acts as a protective layer against abrasive wear of the tool. (Author)

  9. Physical chemistry of WC-12 %Co coatings deposited by thermal spraying at different standoff distances

    Energy Technology Data Exchange (ETDEWEB)

    Afzal, Muhammad; Ahmed, Furqan; Anwar, Muhammad Yousaf; Ali, Liaqat; Ajmal, Muhammad [Univ. of Engineering and Technology, Metallurgical and Materials Engineering, Lahore (Pakistan); Khan, Aamer Nusair [Institute of Industrial and Control System, Rawalpindi (Pakistan)

    2015-09-15

    In the present research, WC-12 %Co cermet coatings were deposited on AISI-321 stainless steel substrate using air plasma spraying. During the deposition process, the standoff distance was varied from 80 to 130 mm with 10 mm increments. Other parameters such as current, voltage, time, carrier gas flow rate and powder feed rate etc. were kept constant. The objective was to study the effects of spraying distance on the microstructure of as-sprayed coatings. The microscopic analyses revealed that the band of spraying distance ranging from 90 to 100 mm was the threshold distance for optimum results, provided that all the other spraying parameters were kept constant. In this range of threshold distance, minimum percentages of porosity and defects were observed. Further, the formation of different phases, at six spraying distances, was studied using X-ray diffraction, and the phase analysis was correlated with hardness results.

  10. WC WAVE - Integrating Diverse Hydrological-Modeling Data and Services Into an Interoperable Geospatial Infrastructure

    Science.gov (United States)

    Hudspeth, W. B.; Baros, S.; Barrett, H.; Savickas, J.; Erickson, J.

    2015-12-01

    WC WAVE (Western Consortium for Watershed Analysis, Visualization and Exploration) is a collaborative research project between the states of Idaho, Nevada, and New Mexico that is funded under the National Science Foundation's Experimental Program to Stimulate Competitive Research (EPSCoR). The goal of the project is to understand and document the effects of climate change on interactions between precipitation, vegetation growth, soil moisture and other landscape properties. These interactions are modeled within a framework we refer to as a virtual watershed (VW), a computer infrastructure that simulates watershed dynamics by linking scientific modeling, visualization, and data management components into a coherent whole. Developed and hosted at the Earth Data Analysis Center, University of New Mexico, the virtual watershed has a number of core functions which include: a) streamlined access to data required for model initialization and boundary conditions; b) the development of analytic scenarios through interactive visualization of available data and the storage of model configuration options; c) coupling of hydrological models through the rapid assimilation of model outputs into the data management system for access and use by sequent models. The WC-WAVE virtual watershed accomplishes these functions by provision of large-scale vector and raster data discovery, subsetting, and delivery via Open Geospatial Consortium (OGC) and REST web service standards. Central to the virtual watershed is the design and use of an innovative array of metadata elements that permits the stepwise coupling of diverse hydrological models (e.g. ISNOBAL, PRMS, CASiMiR) and input data to rapidly assess variation in outcomes under different climatic conditions. We present details on the architecture and functionality of the virtual watershed, results from three western U.S. watersheds, and discuss the realized benefits to watershed science of employing this integrated solution.

  11. Performance of Flame Sprayed Ni-WC Coating under Abrasive Wear Conditions

    Science.gov (United States)

    Harsha, S.; Dwivedi, D. K.; Agarwal, A.

    2008-02-01

    This paper describes the influence of a post spray heat treatment on the microstructure, microhardness and abrasive wear behavior of the flame sprayed Ni-WC (EWAC 1002 ET) coating deposited on the mild steel. Coatings were deposited by using an oxy-acetylene flame spraying torch (Superjet Eutalloy L & T, India). The wear behavior of the coating was evaluated using a pin on disc wear system against SiC abrasive medium of 120 and 600 grades at 5, 10, 15, and 20 N normal load. Results revealed that the influence of normal load on wear is governed by the microstructure, hardness and abrasive grit size. The heat treatment increased average microhardness of the coating. However, it was found that the hardness does not correctly indicate the abrasive wear resistance of Ni-WC coating in an as sprayed and heat treated condition. The heat treatment of the coating improved its abrasive wear resistance against fine abrasive medium while the wear resistance against coarse abrasive was found to be a function of a normal load. At low-normal load (5 and 10 N) the heat treated coating showed lower-wear rate than as spayed coating while at high-normal loads (15 and 20 N) heat treated coating was subjected to higher-wear rate than as sprayed coating. In general, an increase in normal load increased the wear rate. The scanning electron microscopy study indicated that the wear largely takes place by groove formation and scoring of eutectic matrix and the fragmentation of the carbide particles.

  12. Study on the diamond/ultrafine WC-Co cermets interface formed in a SPS consolidated composite

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Nanocrystalline WC-Co composite powder and coated tungsten diamond by using vacuum vapor deposition were consolidated by the spark plasma sintering (SPS) process to prepare diamond-enhanced WC-Co cemented carbide composite materials. The interface microstructures between coated tungsten diamond and WC-Co cemented carbide matrix were investigated by scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDXS). The results showed that there is a transitional layer between the diamond and the matrix, in which the carbon content is 62.97wt.%, and the content of cobalt in the transitional zone is 6.19wt.%; the content of cobalt in the WC-Co cemented carbide matrix is 6.07wt.%, in which the carbon content is 15.95wt.%, and the content of cobalt on the surface of diamond is 7.30wt.%, in which the carbon content is 80.38wt.%. The transitional zone prevents the carbon atom of the diamond from spreading to the matrix, in which the carbon content does coincide with the theoretical value of the raw nanocomposite powders, and the carbon content forms a graded distribution among the matrix, transitional zone, and the surface of diamond; after the 1280℃ SPS consolidated process the diamond still maintains a very good crystal shape, the coated tungsten on the surface of the diamond improves thermal stability of the diamond and increases the bonding strength of the interface between the diamond and the matrix.

  13. Modelling and experimental investigation of process parameters in WEDM of WC-5.3 % Co using response surface methodology

    Directory of Open Access Journals (Sweden)

    K. Jangra

    2012-11-01

    Full Text Available Tungsten carbide-cobalt (WC-Co composite is a difficult-to-machine material owing to its excellent strength and hardness at elevated temperature. Wire electrical discharge machining (WEDM is a best alternative for machining of WC-Co composite into intricate and complex shapes. Efficient machining of WC-Co composite on WEDM is a challenging task since it involves large numbers of parameters. Therefore, in present work, experimental investigation has been carried out to determine the influence of important WEDM parameters on machining performance of WC-Co composite. Response surface methodology, which is a collection of mathematical and experimental techniques, was utilised to obtain the experimental data. Using face-centered central composite design, experiments were conducted to investigate and correlate the four input parameters: pulse-on time, pulse-off time, servo voltage and wire feed for three output performance characteristics – cutting speed (CS, surface roughness (SR and radial overcut (RoC. Using analysis of variance on experimental data, quadratic vs. two-factor interaction (2FI models have been suggested for CS and RoC while two-factor interaction (2FI has been proposed for SR. Using these mathematical models, optimal parameters can be determined easily for desired performance characteristics, and hence a trade-off can be made among different performance characteristics.

  14. Kinetics of the formation of metal binder gradient in WC-Co by carbon diffusion induced liquid migration

    Energy Technology Data Exchange (ETDEWEB)

    Guo Jun [Department of Metallurgical Engineering, University of Utah, 135 S. 1460 E. Room 412, Salt Lake City, UT 84112 (United States); Fang, Zhigang Zak, E-mail: zak.fang@utah.edu [Department of Metallurgical Engineering, University of Utah, 135 S. 1460 E. Room 412, Salt Lake City, UT 84112 (United States); Fan Peng; Wang Xu [Department of Metallurgical Engineering, University of Utah, 135 S. 1460 E. Room 412, Salt Lake City, UT 84112 (United States)

    2011-06-15

    Cemented tungsten carbide (WC-Co) with a cobalt content gradient from the surface to the bulk of a sintered piece is an example of a functionally graded material, the mechanical properties of which are optimized by the unique gradient microstructure, giving rise to superior combinations of wear resistance vs. fracture toughness. A process for creating such cobalt gradients in WC-Co was developed recently based on heat treatments of fully sintered WC-Co materials in carburizing atmospheres. A study of the kinetics of the process is necessary to fully understand the mechanisms of the process in order to achieve desired or designed gradients. In this paper, a series of carburizing experiments were conducted to examine the effects of key process parameters including temperature, composition of the atmosphere, and time on the overall kinetics of the process. A kinetic model was established to predict the thickness of the gradient as a function of these process variables, enabling the design of functionally graded WC-Co through controlling atmosphere and time.

  15. The Effects of Particle Size on the Surface Properties of an HVOF Coating of WC-Co

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Tong Yul; Yoon, Jae Hong; Yoon, Sang Hwan; Joo, Yun Kon [Changwon National University, Changwon (Korea, Republic of); Choi, Won Ho; Son, Young Bok [Xinix Metallizing Co., Ltd, Gyungnam (Korea, Republic of)

    2017-04-15

    The effects of particle size on the surface properties of HVOF spray coating were studied to improve of the durability of metal components. Micro and nano sized WC-12Co powders were coated on the surface of Inconel718, and the effects of particle size on surface properties were studied. Surface hardness was reduced when the particle sizes of the powder were decreased, because the larger specific surface area of the smaller particles caused greater heat absorption and decomposition of the hard WC to less hard W{sub 2}C and graphite. Porosity was increased by decreasing the particle size, because the larger specific surface area of the smaller particles caused a greater decomposition of WC to W{sub 2}C and free carbon. The free carbon formed carbon oxide gases which created the porous surface. The friction coefficient was reduced by decreasing the particle size because the larger specific surface area of the smaller particles produced more free carbon free Co and Co oxide which acted as solid lubricants. The friction coefficient increased when the surface temperature was increased from 25 to 500 ℃, due to local cold welding. To improve the durability of metal mechanical components, WC-Co coating with the proper particle size is recommended.

  16. Residual stress and crack initiation in laser clad composite layer with Co-based alloy and WC + NiCr

    Science.gov (United States)

    Lee, Changmin; Park, Hyungkwon; Yoo, Jaehong; Lee, Changhee; Woo, WanChuck; Park, Sunhong

    2015-08-01

    Although laser cladding process has been widely used to improve the wear and corrosion resistance, there are unwanted cracking issues during and/or after laser cladding. This study investigates the tendency of Co-based WC + NiCr composite layers to cracking during the laser cladding process. Residual stress distributions of the specimen are measured using neutron diffraction and elucidate the correlation between the residual stress and the cracking in three types of cylindrical specimens; (i) no cladding substrate only, (ii) cladding with 100% stellite#6, and (iii) cladding with 55% stellite#6 and 45% technolase40s. The microstructure of the clad layer was composed of Co-based dendrite and brittle eutectic phases at the dendritic boundaries. And WC particles were distributed on the matrix forming intermediate composition region by partial melting of the surface of particles. The overlaid specimen exhibited tensile residual stress, which was accumulated through the beads due to contraction of the coating layer generated by rapid solidification, while the non-clad specimen showed compressive. Also, the specimen overlaid with 55 wt% stellite#6 and 45 wt% technolase40s showed a tensile stress higher than the specimen overlaid with 100% stellite#6 possibly, due to the difference between thermal expansion coefficients of the matrix and WC particles. Such tensile stresses can be potential driving force to provide an easy crack path ways for large brittle fractures combined with the crack initiation sites such as the fractured WC particles, pores and solidification cracks. WC particles directly caused clad cracks by particle fracture under the tensile stress. The pores and solidification cracks also affected as initiation sites and provided an easy crack path ways for large brittle fractures.

  17. Coating Properties of WC-Ni Cold Spray Coating for the Application in Secondary Piping System of Nuclear Power Plants

    Energy Technology Data Exchange (ETDEWEB)

    Kim, JeongWon; Kim, Seunghyun; Kim, Ji Hyun [UNIST, Ulsan (Korea, Republic of)

    2015-10-15

    As a result of FAC(flow accelerated corrosion), severe accidents, failure of carbon steel like a Mihama Unit-3 occurred. Chemical composition change of carbon steel or coating to inner surface is one of methods to improve corrosion properties. Among them, thermal spray coating is convenient solution to apply at industry. Powder is melted at blast furnace and ejected to substrate. After adhesion, substrate and coating layer is cooled down and coated layer protects steel from corrosion finally. However high thermal energy is transferred to substrate and coating layer so it leads high thermal residual stress in coating procedure. Besides, high temperature for melting powder makes unexpected chemical reaction of powder like an oxidation or carburization. Whereas, cold spray uses low temperature comparing with other thermal spray. Thermal energy is used for not melting powder but high kinetic energy of powder and plastic deformation during collision. Therefore, fuel such as oxygen-acetylene gas is not needed. It needs carrier gas, compressed air, nitrogen or helium, to increase kinetic energy of powder and move powder to substrate. Comparing cold spray with high velocity oxy fuel (HVOF), one of thermal spray, cold spray coating layer contains only WC and Co. One of other problem about WC is brittleness during coating. To improve deformability of WC, binder metal is added. For example, Co, Cr, Ni, Cu, Al, Fe or etc. Additionally, binder metal lowering melting temperature of composite powder increases coating properties. Among them, Co which is widely used as binder metal maintains mechanical properties like a hardness and improves corrosion properties. Therefore Co is not suitable for binder metal of WC coating. In contrast, Ni has better corrosion resistance to alkaline environment and makes lower melting temperature. Moreover, in a view of cold spray, FCC structure has better deformability than BCC or HCP, and BCC has lowest deformability. WC is BCC structure so it

  18. Microstructure and performance of in-situ synthesis Ti(C,N)-WC/Ni60A matrix composites coating%原位合成Ti(C,N)-WC/Ni60A基复合涂层显微结构及性能

    Institute of Scientific and Technical Information of China (English)

    屈平; 马跃进; 赵建国; 刘俊峰; 郝建军

    2014-01-01

    which the heat source was provided by the DML-300 plasma welding machine to melt and react between the depositing material components to synthesize composite ceramic coating in-situ. The plasma cladding technology parameters are: The scanning width of single channel is 4-5 mm; Working current is 200 A; Working voltage is 20 V; Argon is used as the shielding gas and the ion gas,the flow of them are 6-8 L/min, 0.6 L/min; Working distance is 4mm, Scanning speed is 150 mm/min. Composition, microstructure, organization and performance are analyzed by scanning electron microscope (SEM), energy disperse spectrometer (EDS), X-ray diffractometer (XRD), microhardness tester and metallurgical microscope. The results show that Ti powder, graphite powder, TiN powder of the pre-coated layer was synthesized in-situ granular new phase Ti(C,N) during the plasma cladding process. The new phase Ti(C,N) granules are uniformly dispersed in the cladding coating, and mainly form the core- ring structure composed of the hard phase, coated phase, and adhesive phase. Ti(C,N) and WC disperse uniformly in the Fe-Ni adhesive phase, Ti(C,N)-WC/Ni60A composite coating metallurgically combined with the substrate is prepared. Polygonal flake WC distributes in the cladding coating surface and the core-ring structure disperses among the adhesive phase of the subsurface. The surface hardness is bigger than the subsurface. The average hardness of the coating is HV0.51750, up to HV0.52040, and about 10 times of the microhardness of Q235B steel substrate. The strengthening mechanism of the cladding coating is both fine-grain strengthening and dispersion strengthening. The wear quantity of the cladding coating is about 1/6 of the new cutter material 65Mn steel. The wear mechanism of the cladding coating is mainly abrasive wear. There were not obvious existing furrows and the signs of wear and tear on the coating have a lower friction coefficient and an excellent dry sliding wear resistance. The plasma

  19. 34 CFR 85.942 - ED Deciding Official.

    Science.gov (United States)

    2010-07-01

    ...) Definitions § 85.942 ED Deciding Official. The ED Deciding Official is an ED officer who has delegated authority under the procedures of the Department of Education to decide whether to affirm a suspension or enter a debarment. Authority: E.O. 12549 (3 CFR, 1986 Comp., p. 189), E.O. 12689 ( 3 CFR, 1989 Comp., p...

  20. edX e-learning course development

    CERN Document Server

    Gilbert, Matthew A

    2015-01-01

    If you are an educator creating a course for edX or a corporate trainer using Open edX for large-scale learning and development initiatives, then edX E-Learning Course Development is the ideal book for you.

  1. La Costituzione Islandese: storia ed evoluzione

    Directory of Open Access Journals (Sweden)

    Fabio Quartino

    2011-03-01

    Full Text Available "La Costituzione Islandese: storia ed evoluzione" is a degree thesis defended on 15th July 2009 by Fabio Quartino under the supervision of Prof. Andrea Canepa of the University of Genoa, Italy. It offers an extensive overview of Icelandic history aimed at finding out the roots of the nation's constitutional order, which is currently in the process of being revised by the first ever elected constitutional assembly in the life of the country. Fabio Quartino's work wishes to be a source of useful information for Italian-speaking scholars who have an interest in Iceland's constitutional history and may not have access to comprehensive overviews in their native tongue.

  2. The Preparation, Preparation Mechauism and Properties of Extra Coarse-grained WC-Co Hardmetals%超粗晶WC-Co硬质合金的制备方法与机理及性能研究

    Institute of Scientific and Technical Information of China (English)

    聂洪波

    2016-01-01

    采用加入球磨活化的细WC粉的方法,成功制备了WC截线晶粒度大于6.5μm的超粗晶硬质合金。对制备机理进行了分析,并对所制备超粗晶硬质合金的金相、热导率、断裂韧性和抗氧化性等进行测定。结果表明:活化细粉在固相烧结阶段全部消失,可以增加烧结活性并抑制超粗晶粒溶解、粒径减小;超粗晶硬质合金WC晶粒度分布窄,晶界平直;热导率和断裂韧性是同样钴含量为0.8μmWC-Co硬质合金的两倍以上,具有优良断裂韧性是由于其可以发生塑性变形;在超粗晶硬质合金中添加镍并不能显著提高抗氧化性。%Extra coarse-grained hardmetals with WC linear-intercept grain size of more than 6.5μm were prepared successfully by adding activated fine WC powders during ball milling. Its metallography, thermal conductivity, fracture toughness and oxidation resistance of these hardmetals were tested. The results indicated that the activated powders, which improved the sintering activity and inhibited extra coarse WC powders dissolution, disappeared during solid phase sintering stage. The grain boundaries of WC with narrow size distribution are straight. Thermal conductivities and fracture toughness are more than two times of 0.8 μm WC hardmetals with the same cobalt content. The favorable fracture toughness was attributed to the plastic deformation of extra coarse-grained harmetals. The oxidation resistance of the hardmetals with addition of nickel hasn't significantly improved.

  3. 适宜碳化钨含量提高Ti(C,N)-WC涂层耐磨耐蚀性%Appropriate WC content improving wear and corrosion resistance of Ti(C, N)-WC coating

    Institute of Scientific and Technical Information of China (English)

    屈平; 马跃进; 赵建国; 马璐萍; 刘俊峰

    2014-01-01

    In order to improve the surface strength of the agricultural machinery key components, the in-situ synthesis of Ti(C,N)-WC composite coating with various WC contents was prepared on Q235B steel specimen surface by reactive plasma cladding technology. Firstly, raw materials were the titanium powder, graphite powder, TiN powder, WC powder and Ni60A powder, which were mixed according to the mass fraction ratio of 28:7:15:0:50, 28:7:15:6:44, 28:7:15:12:38, 28:7:15:15:35, 28:7:15:18:32. The five components of the powder were respectively placed in a planetary-type ball mill DQM, milled for 6 hours, were made a mixed powder paste with 504 of the glue which was the adhesive, and then were uniformly coated on the surface of pretreated Q235B specimen. Secondly, the five samples were placed in the vacuum drying oven and were dried under 80℃. By the plasma cladding technology that DML-300 plasma welding machine provided the heat source and the plasma arc single channel was used to scan to clad, the pre-coated raw material components occurred melting and chemical reaction and synthesized Ti(C,N) metal ceramic composite coating with different WC contents in situ. The morphology, microstructure, phase, wear and corrosion resistance of the Ti(C,N)-WC composite coating were analyzed by scanning electron microscope (SEM), X-ray diffractometer (XRD), micro hardness tester, abrasion testing machine and electrochemical workstation. The results indicated that the granular new phase Ti(C,N) were synthesized in-situ on Q235B steel during the plasma cladding process and the composite coatings were made, which were composed of hard phase, ring phase and binder phase, and had a good metallurgical combination with Q235B steel substrate. Appropriate WC content can promote the formation of ring phase, which effectively improved the wettability of the metal ceramic hard phase and binder phase, prevented the hard phase particles from moving closer to each other, inhibited the hard phase grain

  4. 添加TiC对激光粒子沉积WC-Co-Cr 和WC-Ni涂层性能的影响%Effects of TiC addition on properties of laser particle deposited WC-Co-Cr and WC-Ni coatings

    Institute of Scientific and Technical Information of China (English)

    B.A.OBADELE; P.A.OLUBAMBI; O.T.JOHNSON

    2013-01-01

    The mechanisms by which titanium carbide (TiC) improves the properties of tungsten carbide (WC) coatings deposited on duplex stainless steels using laser particle injection technique were investigated. The relationships between laser process parameters and the synthesized composite were studied. The morphologies and microstructures of the feedstock powders and composite coatings were characterized using scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX) techniques. Surface hardness of the composite layers was determined using the Vickers microhardness tester while its corrosion behaviour in 3.5%NaCl solution was investigated by potentiodynamic polarization curve measurement method. As a result of the laser treatment, microstructures characterized by hard ceramic particles with strong bonding to substrate were formed on the surface layer of the steels. The addition of TiC to WC resulted in microstructures free from cracks, pores and intermetallics which could be detrimental to the properties of the composites. High microhardness was observed and most of the coatings shifted the corrosion potential to more noble values with the pseudo-passive curve.%研究了激光熔覆TiC增强双相不锈钢上WC涂层的机理。分析了激光工艺参数对复合涂层的影响。采用SEM和EDX手段分析了喂料粉末以及复合涂层的形态和微观组织。采用维式硬度计测试了复合涂层的表面硬度,采用动电位曲线法研究了涂层在3.5%NaCl溶液中的耐腐蚀行为。由于激光熔覆处理,在不锈钢表面形成了与基材结合良好的硬陶瓷粒子。添加TiC到WC中得到的复合涂层没有裂缝、孔洞和金属间化合物,没有出现这些对涂层性能不利的缺陷。结果表明,涂层具有较高的显微硬度,且大部分涂层的腐蚀电位变得更负。

  5. Age-related cortical grey matter reductions in non-demented Down's syndrome adults determined by MRI with voxel-based morphometry.

    Science.gov (United States)

    Teipel, Stefan J; Alexander, Gene E; Schapiro, Marc B; Möller, Hans-Jürgen; Rapoport, Stanley I; Hampel, Harald

    2004-04-01

    Ageing in Down's syndrome is accompanied by amyloid and neurofibrillary pathology the distribution of which replicates pathological features of Alzheimer's disease. With advancing age, an increasing proportion of Down's syndrome subjects >40 years old develop progressive cognitive impairment, resembling the cognitive profile of Alzheimer's disease. Based on these findings, Down's syndrome has been proposed as a model to study the predementia stages of Alzheimer's disease. Using an interactive anatomical segmentation technique and volume-of-interest measurements of MRI, we showed recently that non-demented Down's syndrome adults had significantly reduced hippocampus, entorhinal cortex and corpus callosum sizes with increasing age. In this study, we applied the automated and objective technique of voxel-based morphometry, implemented in SPM99, to the analysis of structural MRI from 27 non-demented Down's syndrome adults (mean age 41.1 years, 15 female). Regional grey matter volume was decreased with advancing age in bilateral parietal cortex (mainly the precuneus and inferior parietal lobule), bilateral frontal cortex with left side predominance (mainly middle frontal gyrus), left occipital cortex (mainly lingual cortex), right precentral and left postcentral gyrus, left transverse temporal gyrus, and right parahippocampal gyrus. The reductions were unrelated to gender, intracranial volume or general cognitive function. Grey matter volume was relatively preserved in subcortical nuclei, periventricular regions, the basal surface of the brain (bilateral orbitofrontal and anterior temporal) and the anterior cingulate gyrus. Our findings suggest grey matter reductions in allocortex and association neocortex in the predementia stage of Down's syndrome. The most likely substrate of these changes is alterations or loss of allocortical and neocortical neurons due to Alzheimer's disease-type pathology.

  6. Evolution of the CD163 family and its relationship to the bovine gamma delta T cell co-receptor WC1

    Directory of Open Access Journals (Sweden)

    Baldwin Cynthia L

    2010-06-01

    Full Text Available Abstract Background The scavenger receptor cysteine rich (SRCR domain is an ancient and conserved protein domain. CD163 and WC1 molecules are classed together as group B SRCR superfamily members, along with Spα, CD5 and CD6, all of which are expressed by immune system cells. There are three known types of CD163 molecules in mammals, CD163A (M130, coded for by CD163, CD163b (M160, coded for by CD163L1 and CD163c-α (CD163L1 or SCART, while their nearest relative, WC1, is encoded by a multigene family so far identified in the artiodactyl species of cattle, sheep, and pigs. Results We annotated the bovine genome and identified genes coding for bovine CD163A and CD163c-α but found no evidence for CD163b. Bovine CD163A is widely expressed in immune cells, whereas CD163c-α transcripts are enriched in the WC1+ γδ T cell population. Phylogenetic analyses of the CD163 family genes and WC1 showed that CD163c-α is most closely related to WC1 and that chicken and platypus have WC1 orthologous genes, previously classified as among their CD163 genes. Conclusion Since it has been shown that WC1 plays an important role in the regulation of γδ T cell responses in cattle, which, like chickens, have a high percentage of γδ T cells in their peripheral blood, CD163c-α may play a similar role, especially in species lacking WC1 genes. Our results suggest that gene duplications resulted in the expansion of CD163c-α-like and WC1-like molecules. This expanded repertoire was retained by species known as "γδ T cell high", but homologous SRCR molecules were maintained by all mammals.

  7. Extensions of WC-OWA operator and their applications in risk multi-attribute decision making%WC-OWA算子的拓展及其在风险型多属性决策中的应用

    Institute of Scientific and Technical Information of China (English)

    陈春芳; 朱传喜; 余克弟

    2011-01-01

    The extensions of the weighted C-OWA (WC-OWA) operators ware investigated. Some new aggregation operators and the properties of them were obtained. Futhernore.it proposd an approach to solve risk multi-attribute decision making,in which the attribute values were interval numbers. Finally,an illustrative example was illustrated to show the feasibility of the approach.%研究WC-OWA算子的拓展形式,得到了一些新的数据集成算子,并对其性质进行了研究.在此基础上,探讨属性值以区间形式给出的风险型多属性决策的方法,并用实例进行分析说明该方法的可行性.

  8. The Electro-Spark Deposited WC-Cu Coatings Modified by Laser Treatment / Powłoki WC-Cu Naniesione Elektroiskrowo I Modyfikowane Obróbką Laserową

    Directory of Open Access Journals (Sweden)

    Radek N.

    2015-12-01

    Full Text Available The main objective of the present work was to determine the influence of laser treatment on microstructure, X-ray diffraction, microhardness, surface geometric structure and roughness, corrosion resistance and tribological properties of coatings deposited on C45 carbon steel by the electro-spark deposition (ESD process. The studies were conducted using WC-Cu electrodes produced by the powder metallurgy route. The tests show that the laser-treated electro-spark deposited WC-Cu coatings are characterized by higher corrosion resistance, surface roughness and seizure resistance which come at the expense of lower microhardness. The laser treatment process causes the homogenization of the chemical composition, structure refinement and healing of microcracks and pores of the electro-spark deposited coatings. Laser treated ESD coatings can be applied in sliding friction pairs and as protective coatings.

  9. C/PMR-15基体表面WC-Co涂层制备及性能研究%Research on Deposition and Property of WC-Co Coating on C/PMR-15 Composite Substrate

    Institute of Scientific and Technical Information of China (English)

    曹素红; 马壮; 王富耻; 王全胜; 肖雄

    2006-01-01

    采用超声速火焰喷涂工艺,在预黏结Kevlar-49纤维布的C/PMR-15基体上制备了WC-Co涂层.结果表明:预黏结Kevlar-49纤维布后所得的WC-Co涂层连续致密,这主要是由于Kevlar-49纤维布表面具有凸凹起伏的特征,为涂层粒子沉积提供了有利条件.经260℃至室温的热冲击300次后,涂层未出现明显剥落,原始裂纹基本无扩展现象,这主要是由于Kevlar-49纤维布具有较好的应力缓和功能.

  10. C/PMR-15基体表面WC-Co涂层制备及性能研究%Research on Deposition and Property of WC-Co Coating Based on C/PMR-15 Composite

    Institute of Scientific and Technical Information of China (English)

    曹素红; 马壮; 王富耻; 王全胜; 肖雄

    2006-01-01

    采用超声速火焰喷涂工艺,在预黏接Kevlar-49纤维布的C/PMR-15基体上制备WC-Co涂层.结果表明:预黏接Kevlar-49纤维布后所得的WC-Co涂层连续致密,这主要是由于Kevlar-49纤维布表面具有凸凹起伏的特征,为涂层粒子沉积提供了有利条件.经260℃至室温的热冲击300次后,涂层未出现明显剥落,原始裂纹基本无扩展现象,这主要是由于Kevlar-49纤维布具有较好的应力缓和功能.

  11. INTERFACE BEHAVIOR STUDY OF WC92Co8 COATING BY ELECTROSPARK DEPOSITION%电火花强化WC92Co8复合层界面行为研究

    Institute of Scientific and Technical Information of China (English)

    汪瑞军; 钱乙余; 刘军

    2004-01-01

    利用电火花强化技术在合金表面沉积WC92Co8强化层,能够有效改善基体表面性能.采用Ti合金、45 钢为基体材料,研究了WC92Co8强化层与基体间的界面行为.认为电火花强化技术可在金属基体表面制造高熔点材料强化层.其中Ti合金强化层表面由TiC相、W2C相和少量的W组成.显微硬度达到1 129 HV,强化层厚度大于50 (m.Ti合金表面性能发生质的变化.

  12. Wear and corrosion behavior of W/WC bilayers deposited by magnetron sputtering

    Energy Technology Data Exchange (ETDEWEB)

    Sanchez, N.A. de [Excellence Center for Novel Materials, Universidad del Valle, Cali (Colombia); Jaramillo, H.E. [Science and Engineering of Materials Group, Department of Basic Science of Engineering, Universidad Autonoma de Occidente, Cali (Colombia); Department of Energetic and Mechanic, Universidad Autonoma de Occidente, Cali (Colombia); Bejarano, G. [Excellence Center for Novel Materials, Universidad del Valle, Cali (Colombia); Group for Engineering and Materials Development, CDT ASTIN-SENA, Cali (Colombia); Group of Corrosion and Protection, Antioquia University, Medellin (Colombia); Villamil, B.E.; Teran, G. [Richer Young, COLCIENCIAS, Cali (Colombia)

    2007-07-01

    WC/W coatings were deposited by reactive magnetron sputtering using 40%, 60% and 80% methane CH{sub 4} in the gas mixture. The bilayers were grown on to AISI 420 stainless-steel substrates in order to study the wear and corrosion behavior. Before growing the bilayers, one Ti monolayer was grown to improve the adherence of the coatings to the substrate. The wear resistance and the friction coefficient of the coatings were determined using a pin-on-disk tribometer. All coatings had a friction coefficient of about 0.5. The measured weight lost of the bilayers from each probe allowed the qualitative analysis of wear behavior all coatings. The bilayers grown with 80% methane showed the best abrasive wear resistance and adhesion without failure through the coating in the wear track for dry pin-on-disk sliding. Electrochemical corrosion test showed that the bilayers grown with 80% methane were more resistant to corrosion than the ones uncoated. (copyright 2007 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  13. On modeling the CNC end milling characteristics of Al-7075/WC powder metallurgy composites

    Science.gov (United States)

    Hanuman, N. S. V. N.; Rao, P. Gangadhara; Kumar, B. Sudheer; Karthik, N.

    2017-07-01

    Surface finish and material removal rate are two important factors in the manufacturing which affect acceptability of the product which in turn reflects on the profitability of the organization. The worth of the production setup to produce the components with high material removal rate (MRR) without sacrificing the surface requirements can play vital role in sustainability and profitability of the organization. In this paper, the effect of process parameters on metal removal rate and surface roughness has been investigated in milling of Al7075-MMC with WC as reinforcement element. Cutting speed, feed and depth of cut have been taken as input factors in three level response surface methodologies used for experimentation. Mathematical models have been developed using response surface methodology to predict surface finish, and metal removal rate in term of machining parameters. Depth of cut and feed rate are found to be a dominant parameter for surface roughness; whereas feed rate mainly affects the metal removal rate. The results of mathematical models have been compared with the experimental and found to be in good agreement. The results of predicted model can be used in selection of process parameters to insure desired quality and improved productivity.

  14. Influence of Eta-Phase on Wear Behavior of WC-Co Carbides

    Directory of Open Access Journals (Sweden)

    A. Formisano

    2016-01-01

    Full Text Available Cemented carbides, also known as Widia, are hard metals produced by sintering process and widely used in mechanical machining. They show high cutting capacity and good wear resistance; consequently, they result to be excellent materials for manufacturing cutting tools and sandblast nozzles. In this work, the wear resistance of WC-Co carbides containing Eta-phase, a secondary phase present in the hard metals when a carbon content deficiency occurs, is analyzed. Different mixtures of carbide are prepared and sintered, with different weight percentages of carbon, in order to form Eta-phase and then analyze how the carbon content influences the wear resistance of the material. This characterization is carried out by abrasive wear tests. The test parameters are chosen considering the working conditions of sandblast nozzles. Additional information is gathered through microscopic observations and the evaluation of hardness and microhardness of the different mixtures. The analyses highlight that there is a limit of carbon content below which bad sintering occurs. Considering the mixtures without these sintering problems, they show a wear resistance depending on the size and distribution of the Eta-phase; moreover, the one with high carbon content deficiency shows the best performance.

  15. The kinematical behavior of ORLs and CELs in PNe with [WC] central star

    CERN Document Server

    Pena, Miriam; Rechy-Garcıa, Jackeline; Garcıa-Rojas, Jorge

    2016-01-01

    In Planetary Nebulae (PNe) and HII regions ionic abundances can be derived by using collisionally excited lines (CELs) or recombination lines (ORLs). Such abundances do not coincide for the same ion and usually abundances from ORLs are larger than those from CELs by factors of 2 or larger. The origin of the discrepancy, known as the Abundance Discrepancy Factor is an open problem in astrophysics of gaseous nebulae. It has been attributed to temperature fluctuations in the plasma, tiny metal-rich inclusions embedded in the H-rich plasma, gas inhomogeneities or other processes. In this work we analyze the kinematical behavior of CELs and ORLs in two PNe ionized by [WC] stars, finding that kinematics of ORLS is incompatible with the kinematics of CELs. In particular the expansion velocities from CELs and ORLs for the same ion are different, indicating that ORLs seem to be produced in zones nearer the central star than CELs. This is in agreement with results found by other authors for individual PNe.

  16. Properties of amorphous SiC coatings deposited on WC-Co substrates

    Directory of Open Access Journals (Sweden)

    A.K. Costa

    2003-01-01

    Full Text Available In this work, silicon carbide films were deposited onto tungsten carbide from a sintered SiC target on a r.f. magnetron sputtering system. Based on previous results about the influence of r.f. power and argon pressure upon the properties of films deposited on silicon substrates, suitable conditions were chosen to produce high quality films on WC-Co pieces. Deposition parameters were chosen in order to obtain high deposition rates (about 30 nm/min at 400 W rf power and acceptable residual stresses (1.5 GPa. Argon pressure affects the energy of particles so that films with higher hardness (30 GPa were obtained at low pressures (0.05 Pa. Wear rates of the coated pieces against a chromium steel ball in a diamond suspension medium were found to be about half of the uncoated ones. Hardness and wear resistance measurements were done also in thermally annealed (200-800 °C samples revealing the effectiveness of SiC coatings to protect tool material against severe mechanical degradation resulting of high temperature (above 500 °C oxidation.

  17. The Corrosion Behaviour of WC-Co-Ru Alloys in Aggressive Chloride Media

    Directory of Open Access Journals (Sweden)

    J. H. Potgieter

    2014-01-01

    Full Text Available Hardmetals possess excellent wear resistance, making them suitable alloys in several industrial applications. Mine waters with both dissolved chloride and sulphate salts can be severely corrosive and can limit the application of hardmetal tools in the mining industry. Ru additions to these alloys can refine and improve selected mechanical properties, but its influence on the corrosion resistance is unknown. A series of WC-Co-Ru alloys was evaluated in different chloride containing media to investigate their corrosion resistance. Standard electrochemical corrosion tests, chronoamperometric measurements, and surface analyses with Raman spectroscopy were conducted. An increasing amount of Ru improves the corrosion resistance of all the alloys. The effect is not as dramatic as that observed with stainless steels containing Ru in corrosive media. In both corrosive media Ru decreased the cathodic Tafel constant and has a retarding influence on the cathodic part of the corrosion reaction. Raman analyses indicated the presence of tungsten oxide, hydrated tungsten oxide compounds, and CoO and Co3O4 formed on the alloy surfaces during the corrosion process.

  18. Residual Stress in Brazing of Submicron Al2O3 to WC-Co

    Science.gov (United States)

    Grunder, T.; Piquerez, A.; Bach, M.; Mille, P.

    2016-07-01

    This study evaluated the residual stresses induced by brazing and grinding submicron Al2O3, using different methods. Energy dispersive x-ray spectrometry analysis (EDX) of 72Ag-Cu filler and filler/WC-Co interface showed evidence of atomic diffusion and possible formation of titanium oxide layers between the joint and the bonding materials. An analytical model supported by the finite element method (FEM) based on strain determination due to the difference in variation of thermal expansion was used to assess the stress distribution at the coupling interface and in bulk materials. The model took into account the evolution of the Young's modulus and of the thermal expansion with temperature. The model could be used to follow strain and stress evolutions of the bonded materials during the cooling cycle. The maximum stress rose above -300 MPa at the center of the 100 × 100 × 3 mm ceramic plates. The residual stresses on the external surface of ceramic were investigated by x-ray diffraction (XRD) and indentation fracture method (IFM). After brazing and grinding the plate, the principal stresses were 128.1 and 94.9 MPa, and the shear stress was -20.1 MPa. Microscopic examination revealed grain pull-out promoted by the global residual stresses induced by the brazing and grinding processes. The surface stresses evaluated by the different methods were reasonably correlated.

  19. TC1合金表面电火花沉积WC-8Co涂层界面行为%Interface behavior of WC-8Co coating on Ti alloy produced by electrospark deposition

    Institute of Scientific and Technical Information of China (English)

    汪瑞军; 钱乙余; 黄小鸥; 刘军

    2003-01-01

    钛合金在航空、航天工业得到了广泛应用.但其耐磨性差,对磨面容易产生粘结及对微动磨损敏感等缺点,限制其应用领域的进一步扩大.实践证明,采用电火花强化技术在TC1合金表面制造WC-8Co强化层,可以有效提高TC1基体表面耐磨性能.作者研究了WC-8Co强化层的表面状态、界面行为以及相结构组成,认为TC1合金表面强化高熔点的WC-8Co材料,厚度可大于50 μm;强化层与基体之间存在过渡区;强化层表面由TiC、W2C和少量W组成;强化层截面的显微硬度是基体的3倍以上.

  20. Fabrication of FeAl-WC composite and metal/metal joint using pulse current sintering technique; Pulse tsudenshoketsu gijutsu wo riyoshita FEAl-WC fukugozai narabini kinzoku setsugotaino sakusei

    Energy Technology Data Exchange (ETDEWEB)

    Matsumoto, A.; Kobayashi, K.; Nishio, T.; Ozaki, K.; Sugiyama, A.; Kamiya, A.; Asahina, T. [National Industrial Research Institute of Nagoya,Nagoya (Japan)

    2000-10-25

    Fe-40at%Al+0 {approx} 5at%B powder mixtures were milled in a planetary ball mill under argon atmosphere. The size of the particles decreased with increasing the B content. The mechanical properties such as transverse rupture strength and vickers hardness for Fe-40at%Al+3at%B compacts prepared by pulse current sintering were improved relative to Fe-40at%Al compacts. FeAl{sub 3}-0 {approx} 65vol%WC composites were prepared by using pulse current sintering in vacuum at the sintering temperature of 1,373 - 1,473K. The B added FeAl composites with 50vol% WC exhibited a transverse rupture strength of 1.7GPa and vickers hardness of 1,240. These values were 1.2 {approx} 1.5 times higher than those of FeAl-50vol%WC composites. A novel process for diffusion joining, a combination of pulse current sintering with pseudo-hot isostatic pressing (PHIP-PCS), was proposed. The joining between iron and aluminium tablets using PHIP-PCS process was successfully performed. (author)

  1. Citar e referenciar : APA 6ª ed.

    OpenAIRE

    Marcos, Isabel Marques

    2016-01-01

    A elaboração correta dos trabalhos científicos pressupõe o respeito por um conjunto de princípios normativos de citação e referenciação bibliográfica que salvaguardam os autores das criações intelectuais do uso indevido das mesmas. Partindo de três conceitos: citação, referência bibliográfica e lista de referências apresentam-se as normas da APA 6ª ed. nos seus elementos essenciais. Estas normas, da área da informação e documentação, definem regras para a normalização das referências bibliogr...

  2. Comparative study on discharge conditions in micro-hole electrical discharge machining of tungsten carbide (WC-Co) material

    Institute of Scientific and Technical Information of China (English)

    Hyun-Seok TAK; Chang-Seung HA; Dong-Hyun KIM; Ho-Jun LEE; Hae-June LEE; Myung-Chang KANG

    2009-01-01

    WC-Co is used widely in die and mold industries due to its unique combination of hardness, strength and wear-resistance. For machining difficult-to-cut materials, such as tungsten carbide, micro-electrical discharge machining(EDM) is one of the most effective methods for making holes because the hardness is not a dominant parameter in EDM. This paper describes the characteristics of the discharge conditions for micro-hole EDM of tungsten carbide with a WC grain size of 0.5μm and Co content of 12%. The EDM process was conducted by varying the condenser and resistance values. A R-C discharge EDM device using arc erosion for micro-hole machining was suggested. Furthermore, the characteristics of the developed micro-EDM were analyzed in terms of the electro-optical observation using an oscilloscope and field emission scanning electron microscope.

  3. Ti-WC nanocrystalline coating formed by surface mechanical attrition treatment process on 316L stainless steel.

    Science.gov (United States)

    Aliofkhazraei, M; Rouhaghdam, A Sabour; Ghobadi, E

    2011-10-01

    Nanocrystalline coatings were performed on the surface of 316L stainless steel plates mechanically with a mixture of Ti and WC powders under vacuum conditions. The targets were replaced in the end of the high energy milling rig, while Ti-WC mixture was milled as usual. It is shown that the coatings are nanocrystalline in nature with narrow distribution of average size of nanocrystallites. X-ray diffraction and scanning electron microscopy (with energy-dispersive spectrometer) revealed that the top layer of the coatings is uniform. Microhardness, roughness and primary corrosion tests (tafel tests) proved enhancement of coated samples with respect to raw materials. Transmission electron microscope image of deformed surface confirmed surrounding of nanoparticles by dislocation loops after plastic deformation.

  4. Influence of Interfacial Diffusion on Mechanical Property of Vacuum Fusion Sinter (VFS) WC-Co Composite Coating

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The WC-Co composite coatings bonded tightly to steel substrate have been made by vacuum fusion sinter (VFS). The concentration distribution of some components were measured by the electron probe, and the microstructure and morphology of VFS coatings were observed and analyzed by SEM, X-ray diffractometer and microhardness tester. Diffusion coefficient of every element was calculated by using the experimental results. The influence of the interfacial diffusion on the microstructure, Vickers hardness and interfacial bond strength of the VFS coatings was studied in detail. The experimental results show that there is a metallurgical bond area between the VFS WC-Co coatings and the steel substrate. The VFS coatings are characterized by the gradient hardness of the interface and the high bond strength to the steel substate, both of which are beneficial to the improvement of the wear resistance and corrosion resistance.

  5. Effect of W/C Ratio on Durability and Porosity in Cement Mortar with Constant Cement Amount

    Directory of Open Access Journals (Sweden)

    Yun-Yong Kim

    2014-01-01

    Full Text Available Water is often added to concrete placing for easy workability and finishability in construction site. The additional mixing water can help easy mixing and workability but causes increased porosity, which yields degradation of durability and structural performances. In this paper, cement mortar samples with 0.45 of W/C (water to cement ratio are prepared for control case and durability performances are evaluated with additional water from 0.45 to 0.60 of W/C. Several durability tests including strength, chloride diffusion, air permeability, saturation, and moisture diffusion are performed, and they are analyzed with changed porosity. The changing ratios and patterns of durability performance are evaluated considering pore size distribution, total porosity, and additional water content.

  6. Dissimilar laser brazing of h-BN and WC-Co alloy in Ar atmosphere without evacuation process

    Science.gov (United States)

    Sechi, Y.; Nagatsuka, K.; Nakata, K.

    2012-08-01

    Laser brazing with Ti as an active element in Ag-Cu alloy braze metal has been successfully applied to dissimilar joining of h-BN and WC-Co alloy in Ar (99.999% purity) gas flow atmosphere without any evacuation process. Good wettability of the braze metal with h-BN and WC-Co alloy were confirmed by the observation and structural analysis of the interface by electron probe micro-analysis and scanning acoustic microscopy. The oxidation of titanium was not observed and this showed that the laser brazing with titanium as an active element in braze metal could be performed even in an Ar gas flow atmosphere without an evacuation process using a high-vacuum furnace.

  7. Pareto vs Simmel: residui ed emozioni

    Directory of Open Access Journals (Sweden)

    Silvia Fornari

    2017-08-01

    Full Text Available A cento anni dalla pubblicazione del Trattato di sociologia generale (Pareto 1988 siamo a mantenere vivo ed attuale lo studio paretiano con una rilettura contemporanea del suo pensiero. Ricordato per la grande versatilità intellettuale dagli economisti, rimane lo scienziato rigoroso ed analitico i cui contributi sono ancora discussi a livello internazionale. Noi ne analizzeremo gli aspetti che l’hanno portato ad avvicinarsi all’approccio sociologico, con l’introduzione della nota distinzione dell’azione sociale: logica e non-logica. Una dicotomia utilizzata per dare conto dei cambiamenti sociali riguardanti le modalità d’azione degli uomini e delle donne. Com’è noto le azioni logiche sono quelle che riguardano comportamenti mossi da logicità e raziocinio, in cui vi è una diretta relazione causa-effetto, azioni oggetto di studio degli economisti, e di cui non si occupano i sociologi. Le azioni non-logiche riguardano tutte le tipologie di agire umano che rientrano nel novero delle scienze sociali, e che rappresentano la parte più ampia dell’agire sociale. Sono le azioni guidate dai sentimenti, dall’emotività, dalla superstizione, ecc., illustrate da Pareto nel Trattato di sociologia generale e in saggi successivi, dove riprende anche il concetto di eterogenesi dei fini, formulato per la prima volta da Giambattista Vico. Concetto secondo il quale la storia umana, pur conservando in potenza la realizzazione di certi fini, non è lineare e lungo il suo percorso evolutivo può accadere che l’uomo nel tentativo di raggiungere una finalità arrivi a conclusioni opposte. Pareto collega la definizione del filosofo napoletano alle tipologie di azione sociale e alla loro distinzione (logiche, non-logiche. L’eterogenesi dei fini per Pareto è dunque l’esito di un particolare tipo di azione non-logica dell’essere umano e della collettività.

  8. Contribution of ED admissions to inpatient hospital revenue.

    Science.gov (United States)

    Sacchetti, Alfred; Harris, Russell H; Warden, Todd; Roth, Sandra

    2002-01-01

    Emergency department (ED) practices are traditionally profiled in terms of their patient encounters. Such evaluations reflect a preponderance of outpatient visits while crediting income from admitted patients to traditional hospital-based services. This study evaluates the contribution of ED admissions to inpatient hospital revenue. The study was set at an urban tertiary care community hospital with university affiliation. Information referable to ED patients was collected from the hospital's Universal Billing Code (UB-92)-based patient information warehouse. Data fields referable to hospital charges, insurance type, and disposition were used for analysis of a 1-year period from September 1, 1998 to August 31, 1999. Statistical analysis was through chi square and ANOVA. During the study period 33,174 patients were treated in the ED with 6,671 (20%) admitted to inpatient services. Total hospital charges for all ED patients during this time were $107 million dollars with $9.1 million (8.5%) generated from discharged patients and $98.0 million (91.5%) from admitted ED patients (P revenue for inpatient services for the study period was $288 million of which 34% was contributed from admitted ED patients. ED services represent a major source of inpatient hospital revenue. The recognition of the ED's potential in this area may be lost if income from patients admitted through the ED is credited to traditional hospital-based services.

  9. The blue-light receptor CmWC-1 mediates fruit body development and secondary metabolism in Cordyceps militaris.

    Science.gov (United States)

    Yang, Tao; Guo, Mingmin; Yang, Huaijun; Guo, Suping; Dong, Caihong

    2016-01-01

    Light is an essential factor for pigment formation and fruit body development in Cordyceps militaris, a well-known edible and medicinal fungus. Cmwc-1, a homolog of the blue-light receptor gene white collar-1 (wc-1) in Neurospora crassa, was cloned from the C. militaris genome in our previous study. Here, Cmwc-1 gene inactivation results in thicker aerial hyphae, disordered fruit body development, a significant reduction in conidial formation, and carotenoid and cordycepin production. These characteristics were restored when the ΔCmwc-1 strains were hybridized with wild-type strains of the opposite mating type. A genome-wide expression analysis revealed that there were 1042 light-responsive genes in the wild-type strain and only 458 in the ΔCmwc-1 strain. Among five putative photoreceptors identified, Vivid, cryptochrome-1, and cyclobutane pyrimidine dimer photolyase are strongly induced by light in a Cmwc-1-dependent manner, while phytochrome and cryptochrome-2 were not induced. The transcription factors involved in the fungal light reaction were mainly of the Zn2Cys6 type. CmWC-1 regulates adenylosuccinate synthase, an important enzyme for adenosine de novo synthesis, which could explain the reduction in cordycepin production. Some G protein-coupled receptors that control fungal fruit body formation and the sexual cycle were regulated by CmWC-1, and the cAMP pathway involved in light signal transduction in N. crassa was not critical for the photoreaction in the fungus here. A transcriptional analysis indicated that steroid biosynthesis was more active in the ΔCmwc-1 strain, suggesting that CmWC-1 might switch the vegetative growth state to primordia differentiation by suppressing the expression of related genes.

  10. Study on dry friction and wear resistance of a WC-Co particle reinforced iron matrix composite material

    OpenAIRE

    Zhang Peng; Zeng Shaolian; Zhang Zhiguo

    2013-01-01

    In order to select a suitable material for the rolling mill guide application, the dry sliding friction and wear resistance of a tungsten carbide combining cobalt (WC-Co) particle reinforced chromium cast iron composite material were studied. In particular, the wear resistance was discussed in detail. The results showed that the composite material demonstrates 25 times the wear resistance of high Cr cast iron, and 9 times the wear resistance of heat resistant steel. However, the average frict...

  11. Effectiveness of the WC/rBS oral cholera vaccine in the prevention of traveler's diarrhea: a prospective cohort study.

    Science.gov (United States)

    López-Gigosos, Rosa; Campins, Magda; Calvo, María J; Pérez-Hoyos, Santiago; Díez-Domingo, Javier; Salleras, Luis; Azuara, María T; Martínez, Xavier; Bayas, José M; Ramón Torrell, Josep M; Pérez-Cobaleda, María A; Núñez-Torrón, María E; Gorgojo, Lydia; García-Rodríguez, Magdalena; Díez-Díaz, Rosa; Armadans, Luis; Sánchez-Fernández, Concepción; Mejías, Teresa; Masuet, Cristina; Pinilla, Rafael; Antón, Nieves; Segarra, Pilar

    2013-03-01

    Traveler's diarrhea (TD) is the most frequent disease among people from industrialized countries who travel to less developed ones, especially sub-Saharan Africa, Southern Asia and South America. The most common bacteria causing TD is enterotoxigenic Escherichia coli (ETEC). The WC/rBS cholera vaccine (Dukoral) has been shown to induce cross-protection against ETEC by means of the B subunit of the cholera toxin. The aim of the study was to evaluate the effectiveness of the WC/rBS cholera vaccine in preventing TD. Between May 1 and September 30 (2007), people seeking pre-travel advice in ten Spanish international vaccination centers were included in a prospective cohort study of travelers to cholera risk countries. The incidence rates of TD were adjusted for variables whose frequencies were statistically different (entry point 0.10) between the vaccinated and non-vaccinated cohorts. The vaccinated cohort (n = 544 travelers) included people vaccinated with the WC/rBS cholera vaccine, and the non-vaccinated cohort (n = 530 travelers) by people not vaccinated. The cumulative incidence rate of TD was 1.69 in vaccinated and 2.14 in non-vaccinated subjects. The adjusted relative risk of TD in vaccinated travelers was 0.72 (95% CI: 0.58-0.88) and the adjusted vaccination effectiveness was 28% (95% CI: 12-42). The WC/rBS cholera vaccine prevents TD in 2 out of 7 travelers (preventive fraction: 28%). The number needed to vaccinate (NNV) to prevent 1 case of TD is 10.

  12. Effect of thermal fatigue on the wear resistance of graphite cast iron with bionic units processed by laser cladding WC

    Science.gov (United States)

    Jing, Zhengjun; Zhou, Hong; Zhang, Peng; Wang, Chuanwei; Meng, Chao; Cong, Dalong

    2013-04-01

    Thermal fatigue and wear exist simultaneously during the service life of brake discs. Previous researchers only studied thermal fatigue resistance or abrasion resistance of compact graphite cast iron (CGI), rather than combining them together. In this paper, wear resistance after thermal fatigue of CGI was investigated basing on the principle of bionics, which was close to actual service condition of the brake discs. In the meanwhile, the effect of thermal fatigue on wear resistance was also discussed. Non-smooth bionic units were fabricated by laser cladding WC powder with different proportions (50 wt.%, 60 wt.%, 70 wt.%). Microstructure and microhardness of the units were investigated, and wear mass losses of the samples were also compared. The results indicate that thermal fatigue has a negative effect on the wear resistance. After the same thermal fatigue cycles times, the wear resistance of laser cladding WC samples is superior to that of laser remelting ones and their wear resistance enhances with the increase of WC content.

  13. Erosion behaviour of WC-10Co-4Cr coating on 23-8-N nitronic steel by HVOF thermal spraying

    Science.gov (United States)

    kumar, Avnish; Sharma, Ashok; Goel, S. K.

    2016-05-01

    WC-10Co-4Cr coating was deposited by high-velocity oxy-fuel (HVOF) process on cast and solution treated (1220 °C/150 min) 23-8-N nitronic steel substrates. Solution treated substrate has shown higher toughness, ductility and impact energy with a marginal reduction in hardness as compared to cast substrate. This influence the coating deposition efficiency and erosion behaviour. Erosion resistance of coatings was evaluated by air jet erosion tester on two different impact angles (30° and 90°). Phases, microstructure and eroded surface of the coating were characterised by X-ray diffraction (XRD) analysis and field-emission scanning electron microscopy (FESEM) respectively. It is observed that coating on solution treated substrate was superior to cast substrate. The reason being that coating has dense and well-bonded structure with low porosity, less decarburization and inter-splat oxidation. Higher erosion resistance of coated solution treated 23-8-N nitronic steel was attributed to combination of high fracture toughness and hardness of coating including optimum mechanical properties of the substrate. FESEM analysis reveals that erosion response of WC-10Co-4Cr coating also dependent on the relative size of the impact crater with respect to the WC grain size. Coating is removed by combined mode of ductile and brittle erosion.

  14. WC/Co composite surface structure and nano graphite precipitate induced by high current pulsed electron beam irradiation

    Science.gov (United States)

    Hao, S. Z.; Zhang, Y.; Xu, Y.; Gey, N.; Grosdidier, T.; Dong, C.

    2013-11-01

    High current pulsed electron beam (HCPEB) irradiation was conducted on a WC-6% Co hard alloy with accelerating voltage of 27 kV and pulse duration of 2.5 μs. The surface phase structure was examined by using glancing-angle X-ray diffraction (GAXRD), scanning electron microscope (SEM) and high resolution transmission electron microscope (HRTEM) methods. The surface tribological properties were measured. It was found that after 20 pulses of HCPEB irradiation, the surface structure of WC/Co hard alloy was modified dramatically and composed of a mixture of nano-grained WC1-x, Co3W9C4, Co3W3C phases and graphite precipitate domains ˜50 nm. The friction coefficient of modified surface decreased to ˜0.38 from 0.6 of the initial state, and the wear rate reduced from 8.4 × 10-5 mm3/min to 6.3 × 10-6 mm3/min, showing a significant self-lubricating effect.

  15. Technical Analysis of IEC 61850 Ed 2.0%IEC 61850 Ed 2.0技术分析

    Institute of Scientific and Technical Information of China (English)

    任雁铭; 操丰梅; 张军

    2013-01-01

    对IEC 61850 Ed 2.0的文件构成和技术路线进行了介绍.对比IEC 61850 Ed 1.0,从数据模型、工程配置语言和一致性测试3个方面,对IEC 61850 Ed 2.0的技术特点进行了技术分析.从设备制造商和检测中心2个方面,讨论了如何从IEC 61850 Ed 1.0迁徙到IEC 61850 Ed 2.0.%The profile and technical philosophy of IEC 61850 Ed 2.0 are described. By comparison with IEC 61850 Ed 1.0, an analysis is made of the technical features of IEC 61850 Ed 2.0 data model, substation configuration language and conformance test. A discussion is made of shifting from IEC 61850 Ed 1.0 to IEC 61850 Ed 2.0 with respect to the manufacturer and testing organization.

  16. Structured classification for ED presenting complaints – from free text field-based approach to ICPC-2 ED application

    Directory of Open Access Journals (Sweden)

    Malmström Tomi

    2012-11-01

    Full Text Available Abstract Background Although there is a major need to record and analyse presenting complaints in emergency departments (EDs, no international standard exists. The aim of the present study was to produce structured complaint classification suitable for ED use and to implement it in practice. The structured classification evolved from a study of free text fields and ICPC-2 classification. Methods Presenting complaints in a free text field of ED admissions during a one-year period (n=40610 were analyzed and summarized to 70 presenting complaint groups. The results were compared to ICPC-2 based complaints collected in another ED. An expert panel reviewed the results and produced an ED application of ICPC-2 classification. This study implemented the new classification into an ED. Results The presenting complaints summarized from free text fields and those from ICPC-2 categories were remarkably similar. However, the ICPC-2 classification was too broad for ED; an adapted version was needed. The newly developed classification includes 89 presenting complaints and ED staff found it easy to use. Conclusions ICPC-2 classification can be adapted for ED use. The authors suggest a list of 89 presenting complaints for use in EDs adult patients.

  17. Take steps to curb violence, improve safety for ED personnel.

    Science.gov (United States)

    2011-10-01

    While violent eruptions are well documented in the ED, there is a not a lot of research into what strategies are most effective at both curbing violence and managing incidents when they do occur. Experts suggest that ED managers should consider staff training and visible security measures when developing procedures for dealing with violence. In one survey of ED physicians, more than three-quarters reported at least one incident of workplace violence in the previous 12 months. Researchers report that many EDs post security at the point of entry, but lack security coverage in patient care areas. Experts suggest that verbal de-escalation techniques can be helpful in lowering anxiety levels.They also urge ED managers to bring in assistance when the ED is crowded or waiting times are long.

  18. Role of WC additive on reaction, solid-solution and densification in HfB2–SiC ceramics

    DEFF Research Database (Denmark)

    Hu, Dong-Li; Zheng, Qiang; Gu, Hui

    2014-01-01

    A comparative study of phase components and compositions was performed for the pressureless sintered HfB2–SiC–WC composites by various analytical methods. The relative decrease of HfB2 phase leads to a new reaction of HfO2 removal by WC to create B2O3. By using SiC instead of Si3N4 as milling med...

  19. An Experimental Study on Slurry Erosion Resistance of Single and Multilayered Deposits of Ni-WC Produced by Laser-Based Powder Deposition Process

    Science.gov (United States)

    Balu, Prabu; Hamid, Syed; Kovacevic, Radovan

    2013-11-01

    Single and multilayered deposits containing different mass fractions of tungsten carbide (WC) in nickel (Ni)-matrix (NT-20, NT-60, NT-80) are deposited on a AISI 4140 steel substrate using a laser-based powder deposition process. The transverse cross section of the coupons reveals that the higher the mass fraction of WC in Ni-matrix leads to a more uniform distribution through Ni-matrix. The slurry erosion resistance of the fabricated coupons is tested at three different impingement angles using an abrasive water jet cutting machine, which is quantified based on the erosion rate. The top layer of a multilayered deposit (i.e., NT-60 in a two-layer NT-60 over NT-20 deposit) exhibits better erosion resistance at all three tested impingement angles when compared to a single-layer (NT-60) deposit. A definite increase in the erosion resistance is noted with an addition of nano-size WC particles. The relationship between the different mass fractions of reinforcement (WC) in the deposited composite material (Ni-WC) and their corresponding matrix (Ni) hardness on the erosion rate is studied. The eroded surface is analyzed in the light of a three-dimensional (3-D) profilometer and a scanning electron microscope (SEM). The results show that a volume fraction of approximately 62% of WC with a Ni-matrix hardness of 540 HV resulting in the gouging out of WC from the Ni-matrix by the action of slurry. It is concluded that the slurry erosion resistance of the AISI 4140 steel can be significantly enhanced by introducing single and multilayered deposits of Ni-WC composite material fabricated by the laser-based powder deposition process.

  20. Residual stress and crack initiation in laser clad composite layer with Co-based alloy and WC + NiCr

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Changmin; Park, Hyungkwon; Yoo, Jaehong [Division of Materials Science and Engineering, Hanyang University, Seoul 133-791 (Korea, Republic of); Lee, Changhee, E-mail: chlee@hanyang.ac.kr [Division of Materials Science and Engineering, Hanyang University, Seoul 133-791 (Korea, Republic of); Woo, WanChuck [Neutron Science Division, Korea Atomic Energy Research Institute, Daejeon 305-353 (Korea, Republic of); Park, Sunhong [Research Institute of Industrial Science & Technology, Hyo-ja-dong, Po-Hang, Kyoung-buk, San 32 (Korea, Republic of)

    2015-08-01

    Highlights: • Major problem, clad cracking in laser cladding process, was researched. • Residual stress measurements were performed quantitatively by neutron diffraction method along the surface of specimens. • Relationship between the residual stress and crack initiation was showed clearly. • Ceramic particle effect in the metal matrix was showed from the results of residual stress measurements. • Initiation sites of generating clad cracks were specifically studied in MMC coatings. - Abstract: Although laser cladding process has been widely used to improve the wear and corrosion resistance, there are unwanted cracking issues during and/or after laser cladding. This study investigates the tendency of Co-based WC + NiCr composite layers to cracking during the laser cladding process. Residual stress distributions of the specimen are measured using neutron diffraction and elucidate the correlation between the residual stress and the cracking in three types of cylindrical specimens; (i) no cladding substrate only, (ii) cladding with 100% stellite#6, and (iii) cladding with 55% stellite#6 and 45% technolase40s. The microstructure of the clad layer was composed of Co-based dendrite and brittle eutectic phases at the dendritic boundaries. And WC particles were distributed on the matrix forming intermediate composition region by partial melting of the surface of particles. The overlaid specimen exhibited tensile residual stress, which was accumulated through the beads due to contraction of the coating layer generated by rapid solidification, while the non-clad specimen showed compressive. Also, the specimen overlaid with 55 wt% stellite#6 and 45 wt% technolase40s showed a tensile stress higher than the specimen overlaid with 100% stellite#6 possibly, due to the difference between thermal expansion coefficients of the matrix and WC particles. Such tensile stresses can be potential driving force to provide an easy crack path ways for large brittle fractures

  1. EDs trying not to let the bed bugs bite.

    Science.gov (United States)

    2010-09-01

    As bed bugs have emerged as a growing problem for EDs, managers have developed strategies for prevention and decontamination. Here are some of the approaches they have shared with ED Management: Educate your staff on what they should look for on patients and in rooms that would indicate the presence of bed bugs. Be proactive. Have an exterminator examine your ED on a regular basis. A decontamination room on the outside of the building will prevent the spread of these bugs in your ED.

  2. Vacuum Brazing of WC-8Co Cemented Carbides to Carbon Steel Using Pure Cu and Ag-28Cu as Filler Metal

    Science.gov (United States)

    Zhang, X. Z.; Liu, G. W.; Tao, J. N.; Shao, H. C.; Fu, H.; Pan, T. Z.; Qiao, G. J.

    2017-02-01

    The wetting and spreading behavior of commercial pure Cu and Ag-28Cu alloy on WC-8Co cemented carbide were investigated by the sessile drop technique. The contact angle of both systems obviously decreases with moderately increasing the wetting temperature. Vacuum brazing of the WC-8Co cemented carbide to SAE1045 steel using the pure Cu or Ag-28Cu as filler metal was further carried out based on the wetting results. The interfacial interactions and joint mechanical behavior involving microhardness, shear strength and fracture were analyzed and discussed. An obvious Fe-Cu-Co transition layer is detected at the WC-8Co/Cu interface, while no obvious reaction layer is observed at the whole WC-8Co/Ag-28Cu/SAE1045 brazing seam. The microhardness values of the two interlayers and the steel substrate near the two interlayers increase more or less, while those of WC-8Co cemented carbide substrates adjacent to the two interlayers decrease. The WC-8Co/SAE1045 joints using pure Cu and Ag-28Cu alloy as filler metals obtain average shear strength values of about 172 and 136 MPa, and both of the joint fractures occur in the interlayers.

  3. Effect of Age-Hardening Treatment on Microstructure and Sliding Wear-Resistance Performance of WC/Cu-Ni-Mn Composite Coatings

    Science.gov (United States)

    Liu, Jun; Yang, Shuai; Liu, Kai; Gui, Chibin; Xia, Weisheng

    2017-06-01

    The Cu-Ni-Mn alloy-based hardfacing coatings reinforced by WC particles (WC/Cu-Ni-Mn) were deposited on a steel substrate by a manual oxy-acetylene weld hardfacing method. A sound interfacial junction was formed between the WC particles and the Cu-Ni-Mn alloy metal matrix binder even after the age-hardening treatment. The friction and wear behavior of the hardfacing coatings was investigated. With the introduction of WC particles, the sliding wear resistance of the WC/Cu-Ni-Mn hardfacing coatings was sharply improved: more than 200 times better than that of the age-hardening-treated Cu-Ni-Mn alloy coating. The sliding wear resistances of the as-deposited and the age-hardening-treated WC/Cu-Ni-Mn hardfacing coatings were 1.83 and 2.26 times higher than that of the commercial Fe-Cr-C hardfacing coating, which is mainly ascribed to the higher volume fraction of carbide reinforcement. Owing to the precipitation of the NiMn secondary phase in the Cu-Ni-Mn metal matrix, the age-hardening-treated coating had better wear resistance than that of the as-deposited coating. The main sliding wear mechanisms of the age-hardening-treated coatings are adhesion and abrasion.

  4. Vacuum Brazing of WC-8Co Cemented Carbides to Carbon Steel Using Pure Cu and Ag-28Cu as Filler Metal

    Science.gov (United States)

    Zhang, X. Z.; Liu, G. W.; Tao, J. N.; Shao, H. C.; Fu, H.; Pan, T. Z.; Qiao, G. J.

    2016-12-01

    The wetting and spreading behavior of commercial pure Cu and Ag-28Cu alloy on WC-8Co cemented carbide were investigated by the sessile drop technique. The contact angle of both systems obviously decreases with moderately increasing the wetting temperature. Vacuum brazing of the WC-8Co cemented carbide to SAE1045 steel using the pure Cu or Ag-28Cu as filler metal was further carried out based on the wetting results. The interfacial interactions and joint mechanical behavior involving microhardness, shear strength and fracture were analyzed and discussed. An obvious Fe-Cu-Co transition layer is detected at the WC-8Co/Cu interface, while no obvious reaction layer is observed at the whole WC-8Co/Ag-28Cu/SAE1045 brazing seam. The microhardness values of the two interlayers and the steel substrate near the two interlayers increase more or less, while those of WC-8Co cemented carbide substrates adjacent to the two interlayers decrease. The WC-8Co/SAE1045 joints using pure Cu and Ag-28Cu alloy as filler metals obtain average shear strength values of about 172 and 136 MPa, and both of the joint fractures occur in the interlayers.

  5. Minor injury attendance times to the ED.

    LENUS (Irish Health Repository)

    Conlon, Ciaran

    2009-07-01

    The Health Service Executive (HSE) highlights the need for effective patient throughput and management, whilst providing appropriate staffing and therapeutic interventions. It acknowledges that patient need is integral to the development of a nurse led service and advocates planning staffing levels to reflect arrival times of patients. An observational study of all patients who presented to the emergency department in July 2005 and February 2006 was undertaken (n=7768). The study identified 1577 patients suitable for treatment by the Advanced Nurse Practitioner (ANP) in these two months, which represents 20% of all patient attendances to the ED in this time period. A data collection tool was devised collectively by the ANPs to identify appropriate patients. The findings of the study revealed that 73% of patients suitable for the ANP service presented between the hours of 0800 and 2000, of which 54% attended between 0800 and 1600 h. Sunday emerged as the busiest day in July 2005 whereas Monday was found to be the busiest day in February 2006. Friday was found to be consistently busy for both months.

  6. Measuring the Fidelity of Re-ED Programs.

    Science.gov (United States)

    Meadowcroft, Pamela; Cantrell, Mary Lynn; Cantrell, Robert P.

    2002-01-01

    The effectiveness of a comprehensive intervention like Re-ED (Reeducation of Emotional Disturbed Children) requires a clear definition of the essential components of the model. This article describes an ongoing process to create a program assessment tool for Re-ED. Program fidelity requires being able to specify precisely what is meant by certain…

  7. Teaching Elementary School Social Studies Methods under edTPA

    Science.gov (United States)

    An, Sohyun

    2016-01-01

    This article reports a self-study that analyzes my experience as a teacher educator navigating a turbulent educational landscape with the advent of edTPA. The data consist of my journal entries, the syllabi, handouts, work submitted by my students, and course evaluations. Data were analyzed by using an inductive process to describe how the edTPA…

  8. Effects of EdU labeling on mesenchymal stem cells

    OpenAIRE

    Ning, Hongxiu; Albersen, Maarten; Lin, Guiting; Lue, Tom F.; Lin, Ching-Shwun

    2013-01-01

    Thymidine analog 5-ethynyl-2-deoxyuridine (EdU) has recently been used for tracking mesenchymal stem cells (MSCs). In the present study, we tested whether EdU was cytotoxic and whether it interfered with differentiation, cytokine secretion and migration of MSCs.

  9. Acoustic emission study on flexural behaviour of WC-Co coatings obtained by atmospheric plasma spray; Estudio por emision acustica del comportamiento a flexion de recubrimientos WC-Co obtenidos por plasma atomosferico

    Energy Technology Data Exchange (ETDEWEB)

    Segovia, F.; Klyatskina, E.; Bonache, V.; Salvador, M. D.; Sanchez, E.; Cantavella, V.; Bloem, C.

    2007-07-01

    Plasma spayed cermet coatings WC-Co are used in a wide range of industrial applications, mainly due to their wear resistance even in corrosive environments. the objective of this work is to analyze mechanical response of hard metal coatings by means of three-and four-points bend tests applying acoustic emission technique to determine failure critical strength. It has been observed the effect of supported charge level in structural damage by means of optical microscopy and scanning electron microscopy. Acoustic emission has allowed us to relate damage level to stresses level and then to understand coatings failure mechanism. (Author) 29 refs.

  10. Tolerancia al daño inducido bajo solicitaciones de contacto cíclicas en carburos cementados WC-Co//Tolerance induced damage under cyclic contact loading of WC-Co cemented carbides

    OpenAIRE

    2014-01-01

    El comportamiento mecánico de los carburos cementados WC-Co ha sido estudiado en detalle teniendo en cuenta los defectos preexistentes del material (daño intrínseco). Sin embargo, la información sobre los efectos del daño inducido en servicio (daño extrínseco) en la integridad estructural de estos materiales esescasa. En este contexto, en este trabajo se evalúa la influencia del daño extrínseco en la resistencia mecánica residual de dos calidades con microestructuras diferentes. Para ello, se...

  11. TechEdSat Nano-Satellite Series Fact Sheet

    Science.gov (United States)

    Murbach, Marcus; Martinez, Andres; Guarneros Luna, Ali

    2014-01-01

    TechEdSat-3p is the second generation in the TechEdSat-X series. The TechEdSat Series uses the CubeSat standards established by the California Polytechnic State University Cal Poly), San Luis Obispo. With typical blocks being constructed from 1-unit (1U 10x10x10 cm) increments, the TechEdSat-3p has a 3U volume with a 30 cm length. The project uniquely pairs advanced university students with NASA researchers in a rapid design-to-flight experience lasting 1-2 semesters.The TechEdSat Nano-Satellite Series provides a rapid platform for testing technologies for future NASA Earth and planetary missions, as well as providing students with an early exposure to flight hardware development and management.

  12. The full moon and ED patient volumes: unearthing a myth.

    Science.gov (United States)

    Thompson, D A; Adams, S L

    1996-03-01

    To determine if there is any effect of the full moon on emergency department (ED) patient volume, ambulance runs, admissions, or admissions to a monitored unit, a retrospective analysis of the hospital electronic records of all patients seen in an ED during a 4-year period was conducted in an ED of a suburban community hospital. A full moon occurred 49 times during the study period. There were 150,999 patient visits to the ED during the study period, of which 34,649 patients arrived by ambulance. A total of 35,087 patients was admitted to the hospital and 11,278 patients were admitted to a monitored unit. No significant differences were found in total patient visits, ambulance runs, admissions to the hospital, or admissions to a monitored unit on days of the full moon. The occurrence of a full moon has no effect on ED patient volume, ambulance runs, admissions, or admissions to a monitored unit.

  13. Machinability of Al-SiC metal matrix composites using WC, PCD and MCD inserts

    Directory of Open Access Journals (Sweden)

    Beristain, Jokin

    2014-03-01

    Full Text Available The aim of this work is the study of the machinability of aluminium-silicon carbide Metal Matrix Composites (MMC in turning operations. The cutting tools used were hard metal (WC with and without coating, different grades and geometries of Poly-Crystalline Diamond (PCD and Mono-Crystalline Diamond (MCD. The work piece material was AMC225xe, composed of aluminium-copper alloy AA 2124 and 25% wt of SiC, being the size of the SiC particles around 3 μm. Experiments were conducted at various cutting speeds and cutting parameters in facing finishing operations, measuring the surface roughness, cutting forces and tool wear. The worn surface of the cutting tool was examined by Scanning Electron Microscope (SEM. It was observed that the Built Up Edge (BUE and stuck material is higher in the MCD tools than in the PCD tools. The BUE acts as a protective layer against abrasive wear of the tool.El objetivo de este trabajo es el estudio de la maquinabilidad del material compuesto de matriz metálica aluminio-carburo de silicio en operaciones de torneado. Las herramientas de corte utilizadas han sido de metal duro con y sin recubrimiento, diferentes grados de diamante policristalino (PCD y diamante monocristalino (MCD. El material mecanizado ha sido AMC225xe, compuesto de la aleación de aluminio AA 2124 con un 25% en peso de partículas de SiC con un tamaño medio de 3 μm. Los experimentos se han realizado con diferentes velocidades de corte en una operación de refrentado, midiendo la rugosidad superficial, las fuerzas y el desgaste de la herramienta. La superficie desgastada de la herramienta ha sido examinada en el microscopio electrónico (SEM. Se ha observado que el filo recrecido y el material adherido son mayores en el caso de las herramientas de MCD que en las de PCD. El filo recrecido actúa como una capa protectora contra la abrasión.

  14. Longitudinal Changes in the Government-Certified Index Stage and Requisite Costs for Long-Term Care Insurance System among the Community-Dwelling Demented Elderly in Japan

    Directory of Open Access Journals (Sweden)

    Shunichiro Shinagawa

    2013-01-01

    Full Text Available Background. A new public long-term care (LTC insurance was launched in 2000 in Japan. However, there have been few studies involving factors that increase LTC costs of demented subjects; no follow-up studies involving the Government-Certified Index (GCI and requisite costs related to the causes of dementia. Method. An epidemiological survey was conducted in a rural area in Japan in 1999, and 271 subjects were diagnosed as dementia patients. Age, sex, mini-mental state examination, clinical dementia rating, activity of daily living, causes of dementia, and coexisting physical disease were confirmed. After the LTC insurance has been launched, we tracked the GCI stages and payment amounts every month for 8 years. Result. 209 subjects were certified to be eligible for LTC insurance; however, 13 did not receive any payment. Only 49 out of 209 were alive after the follow-up period. The most common cause of dementia was Alzheimer’s disease (AD, followed by vascular dementia (VaD. There was no significant difference between the mortality rates of the two groups. VaD subjects required higher costs than AD subjects in the total certified period and in GCI stage 5. Conclusion. Our results indicate that causes of dementia can have an impact on the requisite costs for the LTC insurance.

  15. Changes in brain volume and cognition in a randomized trial of exercise and social interaction in a community-based sample of non-demented Chinese elders.

    Science.gov (United States)

    Mortimer, James A; Ding, Ding; Borenstein, Amy R; DeCarli, Charles; Guo, Qihao; Wu, Yougui; Zhao, Qianhua; Chu, Shugang

    2012-01-01

    Physical exercise has been shown to increase brain volume and improve cognition in randomized trials of non-demented elderly. Although greater social engagement was found to reduce dementia risk in observational studies, randomized trials of social interventions have not been reported. A representative sample of 120 elderly from Shanghai, China was randomized to four groups (Tai Chi, Walking, Social Interaction, No Intervention) for 40 weeks. Two MRIs were obtained, one before the intervention period, the other after. A neuropsychological battery was administered at baseline, 20 weeks, and 40 weeks. Comparison of changes in brain volumes in intervention groups with the No Intervention group were assessed by t-tests. Time-intervention group interactions for neuropsychological measures were evaluated with repeated-measures mixed models. Compared to the No Intervention group, significant increases in brain volume were seen in the Tai Chi and Social Intervention groups (p brain volume and improvements in cognition with a largely non-aerobic exercise (Tai Chi). In addition, intellectual stimulation through social interaction was associated with increases in brain volume as well as with some cognitive improvements.

  16. Deconstructing Stereotypes : Ed Bullins' the Taking of Miss Janie = Ed Bullins'in

    Directory of Open Access Journals (Sweden)

    Çiğdem Pala MULL

    2004-06-01

    Full Text Available African-American playwright Ed Bullins is one of the most significant figures to emerge from the Black Arts Movement of the 1960s. His 1975 play The Taking of Miss Janie is a dramatic portrait of the specific events and ideas that created the 1960s, and their impact on the individual consciousnesses of the characters. The play brings into the foreground many issues related to race and ethnicity in America. Even though the general tone of The Taking of Miss Janie is one of violence and gloom, this reading focuses on those moments where love and human affection outshine the sense of destruction predominant in the play.

  17. Kinetics and thermodynamics of H2O dissociation and CO oxidation on the Pt/WC (0001) surface: A density functional theory study

    Science.gov (United States)

    Liang, Yuanyuan; Chen, Litao; Ma, Chun'an

    2017-02-01

    Adsorptions of H2O and CO on the Pt/WC(0001) [pseudomorphic platinum monolayer on WC(0001)] surface have been studied with periodical slab model by PW91 approach of GGA within the framework of density functional theory (DFT). The reaction pathways and mechanisms of H2O dissociation and CO oxidation are also investigated. For a comparison, similar calculation scheme are performed on the Pt (111) surface as well. The adsorption energies of H2O and CO on both concerned surfaces suggest that H2O binds preferentially on the Pt/WC (0001) surface, while CO prefers the metal surface Pt (111), agreeing well with the experimental observation that the tungsten carbides based material is less susceptible to CO poisoning than platinum. The activation energies for the stepwise H2O dehydrogenation reaction show that the progress of H2O dissociation is similar on the two surfaces; and coincidentally the oxidation of CO by surface hydroxyl is much more likely to occur than that by surface oxygen which comes up with the H2O dissociation. Although the activation barrier of H2O dissociation on the Pt/WC (0001) is similar to that on Pt (111), the key oxidant OH specials which play a key role in turning over surface carbon monoxide to carbon dioxide prefer the Pt/WC(0001) surface, and the improved CO oxidation reaction progress confirms that the Pt/WC surface is more CO-tolerant than the pure Pt. According to the electronic structure analysis we find that the increased CO tolerance is ascribed to the downshift of Pt d-band center because of the charge transfer from WC support to the coating surface.

  18. Friction and wear properties of high-velocity oxygen fuel sprayed WC-17Co coating under rotational fretting conditions

    Science.gov (United States)

    Luo, Jun; Cai, Zhenbing; Mo, Jiliang; Peng, Jinfang; Zhu, Minhao

    2016-05-01

    Rotational fretting which exist in many engineering applications has incurred enormous economic loss. Thus, accessible methods are urgently needed to alleviate or eliminate damage by rotational fretting. Surface engineering is an effective approach that is successfully adopted to enhance the ability of components to resist the fretting damage. In this paper, using a high-velocity oxygen fuel sprayed (HVOF) technique WC-17Co coating is deposited on an LZ50 steel surface to study its properties through Vickers hardness testing, scanning electric microscope (SEM), energy dispersive X-ray spectroscopy (EDX), and X-ray diffractrometry (XRD). Rotational fretting wear tests are conducted under normal load varied from 10 N to 50 N, and angular displacement amplitudes vary from 0.125° to 1°. Wear scars are examined using SEM, EDX, optical microscopy (OM), and surface topography. The experimental results reveal that the WC-17Co coating adjusted the boundary between the partial slip regime (PSR) and the slip regime (SR) to the direction of smaller amplitude displacement. As a result, the coefficients of friction are consistently lower than the substrate's coefficients of friction both in the PSR and SR. The damage to the coating in the PSR is very slight. In the SR, the coating exhibits higher debris removal efficiency and load-carrying capacity. The bulge is not found for the coating due to the coating's higher hardness to restrain plastic flow. This research could provide experimental bases for promoting industrial application of WC-17Co coating in prevention of rotational fretting wear.

  19. Diamond film deposition on WC-Co and steel substrates with a CrN interlayer for tribological applications

    Science.gov (United States)

    Chandran, Maneesh; Hoffman, Alon

    2016-06-01

    The most renowned property of diamond is its exceptional hardness. By depositing diamond films on tungsten carbide (WC-Co) and steel substrates, the hardness of diamond can be combined with the toughness of these materials, resulting in an excellent wear resistance material for tribological applications. However, poor adhesion of diamond coating on these substrates leads to a lesser lifetime for the diamond coated tools than expected. The prime reasons for the lack of proper adhesion are the preferential formation of graphitic layer at the interface due to the catalytic activities of cobalt/iron and the interfacial residual stresses due to the mismatch in thermal expansion coefficients of diamond (1.5  ×  10-6 K-1) and WC-Co (5.2  ×  10-6 K-1) or steel (12  ×  10-6 K-1). In this review, we discuss the possibility of using a Cr-N interlayer as a diffusion barrier to prevent the catalytic activities of cobalt/iron and also to relax the interfacial residual stresses to some extent to enhance the adhesion of diamond coatings on these substrates. An overview of the most pertinent results of the last two decades, including the recent progress is introduced. We describe in detail how the Cr-N interlayer with the desired properties is fabricated. We give a concise overview of diamond deposition process, including the methods to vary the grain size from microcrystalline to nanocrystalline, which are suitable for some tribological applications. We describe in detail on surface and interface analysis, residual stress measurements, assessment adhesion strength and tribological performance of diamond coated WC-Co and steel substrates using various characterization techniques. We conclude by highlighting the current progress and future perspectives of diamond coatings on these substrates for tribological applications.

  20. The Effect of WC/C Coating on the Wear of Bevel Gears Used in Coal Mines

    Directory of Open Access Journals (Sweden)

    Waldemar Tuszynski

    2015-09-01

    Full Text Available There are many problems in the operation of spiral bevel gears; for example, difficult lubrication conditions lead to excessively high oil temperature and the risk of severe wear. Thus, the aim of this work was to check whether, by the deposition of a thin, hard, low-friction coating on the teeth flanks of spiral bevel gears, it is possible to improve the resistance to wear, reduce friction and possibly the gear vibrations.The tribological experiments were carried out in two phases. In the first phase, a bevel gear test rig was used (laboratory testing. In the second phase, a verification test was performed using an industrial gear stand (chain conveyor working under conditions typical of coal mines. The low-friction WC/C coating was tested. The coating was deposited on the teeth of the wheels. For reference, the uncoated pairs of spiral bevel gears were tested. In the laboratory testing, a commercial, mineral automotive gear oil of the API GL-5 performance level and 80W-90 viscosity grade was used for lubrication. For lubrication of the industrial gears, a mineral base oil of the low, VG32 viscosity grade was chosen.The results obtained show that, by the deposition of the low-friction WC/C coating on the teeth of the wheel, the following beneficial effects can be achieved in comparison with the case of the uncoated gears: a rise in the resistance to the two forms of severe wear (scuffing and pitting, and a drop in the oil temperature (lower friction. The above effects are accompanied at the first stages of the tests by an undesired, higher level of vibrations in case of the steel-WC/C material combination. However, throughout the test, the vibrations for the two material combinations became similar. Thus, the WC/C coating can be applied to increase the wear resistance and decrease the oil temperature in the transmissions containing spiral bevel gears in, e.g., chain conveyors installed in coal mines.DOI: http://dx.doi.org/10.5755/j01.ms.21.3.7263

  1. Structure-property-correlation in laser surface alloyed AISI 304 stainless steel with WC + Ni + NiCr

    Energy Technology Data Exchange (ETDEWEB)

    Anandan, S. [Dept. of Met. and Mat. Engg., Indian Institute of Technology, Kharagpur 721302 (India); Pityana, Sisa [National Laser Centre, Council of Scientific and Industrial Research, Pretoria (South Africa); Dutta Majumdar, J., E-mail: jyotsna@metal.iitkgp.ernet.in [Dept. of Met. and Mat. Engg., Indian Institute of Technology, Kharagpur 721302 (India)

    2012-02-28

    Highlights: Black-Right-Pointing-Pointer Optimization of process parameters for development of WC dispersed composite with Ni + NiCr as binder. Black-Right-Pointing-Pointer Development of fine grained {gamma}-stainless steel with the dispersion of very fine carbides (WC, W{sub 2}C, M{sub 6}C and M{sub 23}C{sub 6}). Black-Right-Pointing-Pointer A significantly improved microhardness of the top surface (to 700-1350 VHN) as compared to as-received matrix (220 VHN) and its correlation with microstructures. Black-Right-Pointing-Pointer Detailed microstructural evolution of the alloyed zone and its correlation with process parameters. Black-Right-Pointing-Pointer Graded hardness distribution is achieved when lased with a low scan speed. - Abstract: The present study concerns a detailed investigation of the characteristics and properties of the alloyed zone formed in laser surface alloyed AISI 304 stainless steel with WC + Ni + NiCr (in the ratio of 70:15:15). Laser surface alloying has been carried out using a 5 kW continuous wave (CW) Nd:YAG laser (at a beam diameter of 4 mm), with the output power ranging from 1 to 3 kW and scan speed from 0.005 m/s to 0.1 m/s by simultaneous feeding of precursor powder (at a flow rate of 20 mg/s) and using Ar shroud at a gas flow rate of 5 l/min. The effect of laser power and scan speed on the characteristics of the surface alloyed layer (microstructures, phases and composition) and property (microhardness) have been investigated in details. Laser surface alloying leads to development of fine grained {gamma}-stainless steel with the dispersion of WC, W{sub 2}C, M{sub 6}C and M{sub 23}C{sub 6}. The microhardness of the alloyed zone is significantly improved to a maximum value of 1350 VHN as compared to 220 VHN of as-received {gamma}-stainless steel. The optimum parameters for laser processing were derived.

  2. Influencia de la microestructura en el comportamiento tribológico de carburos cementados (WC-Co) borados

    OpenAIRE

    2015-01-01

    En este trabajo se analiza la evolución microestructural y su influencia en el comportamiento tribológico de carburos cementados WC-Co modificados superficialmente mediante un tratamiento termoquímico de borado. El borado superficial de las muestras se realizó mediante el método de boración por polvos sólidos. La caracterización microestructural y tribológica consistió en la observación de la capa borada, y la determinación de propiedades tales como la microdureza superficial y la resistencia...

  3. The Effect of WC/C Coating on the Wear of Bevel Gears Used in Coal Mines

    Directory of Open Access Journals (Sweden)

    Waldemar Tuszynski

    2015-09-01

    Full Text Available There are many problems in the operation of spiral bevel gears; for example, difficult lubrication conditions lead to excessively high oil temperature and the risk of severe wear. Thus, the aim of this work was to check whether, by the deposition of a thin, hard, low-friction coating on the teeth flanks of spiral bevel gears, it is possible to improve the resistance to wear, reduce friction and possibly the gear vibrations.The tribological experiments were carried out in two phases. In the first phase, a bevel gear test rig was used (laboratory testing. In the second phase, a verification test was performed using an industrial gear stand (chain conveyor working under conditions typical of coal mines. The low-friction WC/C coating was tested. The coating was deposited on the teeth of the wheels. For reference, the uncoated pairs of spiral bevel gears were tested. In the laboratory testing, a commercial, mineral automotive gear oil of the API GL-5 performance level and 80W-90 viscosity grade was used for lubrication. For lubrication of the industrial gears, a mineral base oil of the low, VG32 viscosity grade was chosen.The results obtained show that, by the deposition of the low-friction WC/C coating on the teeth of the wheel, the following beneficial effects can be achieved in comparison with the case of the uncoated gears: a rise in the resistance to the two forms of severe wear (scuffing and pitting, and a drop in the oil temperature (lower friction. The above effects are accompanied at the first stages of the tests by an undesired, higher level of vibrations in case of the steel-WC/C material combination. However, throughout the test, the vibrations for the two material combinations became similar. Thus, the WC/C coating can be applied to increase the wear resistance and decrease the oil temperature in the transmissions containing spiral bevel gears in, e.g., chain conveyors installed in coal mines.DOI: http://dx.doi.org/10.5755/j01.ms.21.3.7263

  4. Research on Cutting Performance of Ti(C,N)-based Cermets with WC and Mo_2C Addition%WC和Mo_2C添加对Ti(C,N)基金属陶瓷切削性能的影响

    Institute of Scientific and Technical Information of China (English)

    吴悦梅; 熊计; 陈云; 郭智兴; 范洪远

    2011-01-01

    Mo2C has been used in conventional Ti(C,N)-based cermets to improve its wettability between hard phase and binder phase.Recently,some researchers have attempted to develop Ti(C,N)-based cermets free of Mo.To investigate the effect of replacing Mo2C by WC in conventional Ti(C,N)-based cermets,the cutting performance of cermets with the addition of WC and Mo2C was studied,respectively.Wear morphology of cutting tool was observed by SEM,and element distribution of tool surface was analyzed by EDS.The results showed that the cutting tool life of cermets with WC addition was equal to that with Mo2C addition.When the size of the initial WC powder decreased,the cutting tool life could be prolonged,the zonal tangle chip changed to helix chip,and the chip build-up could be reduced.Diffusion wear,oxidation wear accompanied by abrasive wear were considered to be the main wear mechanisms of the cermets.%传统的Ti(C,N)基金属陶瓷刀具材料广泛采用Mo2C来改善粘结相对硬质相的润湿性,近年来Mo的价格不断上涨,寻找低成本金属代替Mo已成为Ti(C,N)基金属陶瓷的发展趋势。为了探讨WC代替Mo2C添加的可行性及其效果,研究了WC和Mo2C添加对Ti(C,N)基金属陶瓷切削性能的影响,采用电子扫描显微镜(SEM)观察刀具的磨损形貌,通过能谱分析(EDS)分析磨损表面的元素分布,并对刀具的主要磨损机理进行分析。实验结果表明,添加WC的金属陶瓷的切削长度和添加Mo2C的相当,将原始WC粉末粒度细化后,不仅切削

  5. WC5E型铰接式四驱矿用自卸车传动轴的设计%Design of transmission shafts of WC5E articulated mine dump truck with four-wheel driving

    Institute of Scientific and Technical Information of China (English)

    王庆祥; 郭培燕; 王素慧

    2012-01-01

    针对WC5E型铰接式四驱矿用自卸车的结构特点和传动轴布置形式,通过分析各传动轴的工作状态和运动轨迹,确定了传动轴的长度、伸缩量和断面尺寸等主要性能参数,并根据所传递扭矩和转速对其进行了强度计算和校核,最终设计出满足整车使用要求的传动轴,为此类车辆传动系统的设计提供了方法和依据。%According to the structural features of WC5E articulated mine dump truck with four-wheel driving and the layout of its transmission shafts, after analyzing the operation status and motion track of each transmission shaft, the paper determined the main parameters of the transmission shafts such as the length, shrinkage and cross dimension etc. In addition, the strength calculation and checking of the transmission shafts were conducted according to the transmitted torque and rotary speed. Finally, the transmission shafts meeting the employment requirements of the dump truck were designed, which offered methods and references for design of the transmission system in the truck.

  6. Effect of helium plasma gas flow rate on the properties of WC-12 wt.%Co coatings sprayed by atmospheric plasma

    Directory of Open Access Journals (Sweden)

    Mihailo R. Mrdak

    2014-06-01

    Full Text Available The cermet coatings of WC-12wt.%Co are extensively used to improve the wear resistance of a wide range of technical components. This paper analyses the influence of the plasma gas flow of helium on the microstructure and mechanical properties of WC-12wt.%Co coatings deposited by plasma spraying at atmospheric pressure (APS. In order to obtain homogeneous and denser coatings, three different flows of He ( 8 l/min., 16 l/min. and 32 l/min were used in the research. With the application of He, coatings achieved higher values of hardness due to less degradation of the primary WC carbides. The main goal was to deposit dense and homogeneous layers of WC-12wt.%Co coatings with improved wear resistance for different applications. The test results of the microstructure of the layers were evaluated under a light microscope. The analysis of the microstructure and the mechanical properties of the deposited layers was made in accordance with the standard of Pratt-Whitney. The morphology of the powder particles and the microstructure of the best coating was examined on the SEM (scanning electron microscope. The evaluation of the mechanical properties of the layers was done by applying the HV0.3 method for microhardness testing and by applying tensile testing to test the bond strength. The research has shown that the flow of He plasma gas significantly affects the microstructure, the mechanical properties and the structure of WC-12 wt.%Co coatings.

  7. Improvement of Surface Properties of Inconel718 by HVOF Coating with WC-Metal Powder and by Laser Heat Treatment of the Coating

    Directory of Open Access Journals (Sweden)

    Hui Gon Chun

    2015-01-01

    Full Text Available High-velocity oxygen-fuel (HVOF thermal spray coating with WC-metal powder was carried out by using optimal coating process on an Inconel718 surface for improvement of the surface properties, friction, wear, and corrosion resistance. Binder metals such as Cr and Ni were completely melted and WC was decomposed partially to W2C and graphite during the high temperature (up to 3500°C thermal spraying. The melted metals were bonded with WC and other carbides and were formed as WC-metal coating. The graphite and excessively sprayed oxygen formed carbon oxide gases, and these gases formed porous coating by evolution of the gases. The surface properties were improved by HVOF coating and were improved further by CO2 laser heat treatment (LH. Wear resistance of In718 surface was improved by coating and LH at 25°C and an elevated temperature of 450°C, resulting in reduction of wear trace traces, and was further improved by LH of the coating in reducing wear depth. Corrosion resistance due to coating in sea water was improved by LH. HVOF coating of WC-metal powder on a metal surface and a LH of the coating were highly recommended for the improvement of In718 surface properties, the friction behavior, and wear resistance.

  8. Work function tuning of plasma-enhanced atomic layer deposited WC{sub x}N{sub y} electrodes for metal/oxide/semiconductor devices

    Energy Technology Data Exchange (ETDEWEB)

    Zonensain, Oren; Fadida, Sivan; Eizenberg, Moshe [Department of Materials Science and Engineering, Technion-Israel Institute of Technology, Haifa 32000 (Israel); Fisher, Ilanit; Gao, Juwen; Chattopadhyay, Kaushik; Harm, Greg; Mountsier, Tom; Danek, Michal [Lam Research Corporation, 4000 N. First Street, San Jose, California 95134 (United States)

    2015-02-23

    One of the main challenges facing the integration of metals as gate electrodes in advanced MOS devices is control over the Fermi level position at the metal/dielectric interface. In this study, we demonstrate the ability to tune the effective work function (EWF) of W-based electrodes by process modifications of the atomic layer deposited (ALD) films. Tungsten carbo-nitrides (WC{sub x}N{sub y}) films were deposited via plasma-enhanced and/or thermal ALD processes using organometallic precursors. The process modifications enabled us to control the stoichiometry of the WC{sub x}N{sub y} films. Deposition in hydrogen plasma (without nitrogen based reactant) resulted in a stoichiometry of WC{sub 0.4} with primarily W-C chemical bonding, as determined by x-ray photoelectron spectroscopy. These films yielded a relatively low EWF of 4.2 ± 0.1 eV. The introduction of nitrogen based reactant to the plasma or the thermal ALD deposition resulted in a stoichiometry of WC{sub 0.1}N{sub 0.6–0.8} with predominantly W-N chemical bonding. These films produced a high EWF of 4.7 ± 0.1 eV.

  9. The effect of spraying parameters on micro-structural properties of WC-12%Co coating deposited on copper substrate by HVOF process

    Energy Technology Data Exchange (ETDEWEB)

    Sathwara, Nishit, E-mail: nishit-25@live.in [Fusion Rector Material Development & Characterization Division, Institute for Plasma Research, GIDC Electronics Estate, Sec-25, Gandhinagar-382016 (India); Metallurgical & Materials Engineering Department, Indus University, Ahmedabad-382115 (India); Jariwala, C., E-mail: chetanjari@yahoo.com; Chauhan, N.; Raole, P. M. [Fusion Rector Material Development & Characterization Division, Institute for Plasma Research, GIDC Electronics Estate, Sec-25, Gandhinagar-382016 (India); Basa, D. K. [Metallurgical & Materials Engineering Department, Indus University, Ahmedabad-382115 (India)

    2015-08-28

    High Velocity Oxy-Fuel (HVOF) thermal sprayed coatingmade from Tungsten Carbide (WC) isconsidered as one of the most durable materials as wear resistance for industrial applications at room temperature. WC coating offers high wear resistance due to its high hardness and tough matrix imparts. The coating properties strongly depend on thermal spray processing parameters, surface preparation and surface finish. In this investigation, the effect of variousHVOF process parameters was studied on WC coating properties. The WC-12%Co coating was produced on Copper substrate. Prior to coating, theCopper substrate surface was prepared by grit blasting. WC-12%Co coatings were deposited on Coppersubstrates with varying process parameters such as Oxygen gas pressure, Air pressure, and spraying distance. Microstructure of coating was examined using Scanning Electron Microscope (SEM) and characterization of phasespresentin the coating was examined by X-Ray Diffraction (XRD). Microhardness of all coatingswas measured by VickerMicrohardness tester. At low Oxygen Pressure(10.00 bar), high Air pressure (7bar) and short nozzle to substrate distance of 170mm, best coating adhesion and porosity less structure isachieved on Coppersubstrate.

  10. On the performances and wear of WC-diamond like carbon coated tools in drilling of CFRP/Titanium stacks

    Science.gov (United States)

    Boccarusso, L.; Durante, M.; Impero, F.; Minutolo, F. Memola Capece; Scherillo, F.; Squillace, A.

    2016-10-01

    The use of hybrid structures made of CFRP and titanium alloys is growing more and more in the last years in the aerospace industry due to the high strength to weight ratio. Because of their very different characteristics, the mechanical fastening represent the most effective joining technique for these materials. As a consequence, drilling process plays a key role in the assembly. The one shot drilling, i.e. the contemporary drilling of the stack of the two materials, seems to be the best option both in terms of time saving and assembly accuracy. Nevertheless, due to the considerable different machinability of fiber reinforced plastics and metallic materials, the one shot drilling is a critical process both for the holes quality and for the tools wear. This research was carried out to study the effectiveness of new generation tools in the drilling of CFRP/Titanium stacks. The tools are made of sintered grains of tungsten carbide (WC) in a binder of cobalt and coated with Diamond like carbon (DLC), and are characterized by a patented geometry; they mainly differ in parent WC grain size and binder percentage. Both the cutting forces and the wear phenomena were accurately investigated and the results were analyzed as a function of number of holes and their quality. The results show a clear increase of the cutting forces with the number of holes for all the used drilling tools. Moreover, abrasive wear phenomena that affect initially the tools coating layer were observed.

  11. Efficient recycling of WC-Co hardmetal sludge by oxidation followed by alkali and sulfuric acid treatments

    Science.gov (United States)

    Yang, Dong-hyo; Srivastava, Rajiv Ranjan; Kim, Min-seuk; Nam, Dao Duy; Lee, Jae-chun; Huynh, Hai Trung

    2016-09-01

    We present a process to recycle strategic metals, viz. tungsten and cobalt, from a WC-Co hardmetal sludge (WCHS) via oxidation followed by a two-step hydrometallurgical treatment with alkali and acid solutions. The oxidation of WCHS was investigated in the temperature range of 500 to 1000 °C and optimized at 600 °C to transform the maximum WC into an alkali-soluble WO3. The conditions for the selective dissolution of WO3 in stage-I were optimized as follows: 4.0 M NaOH, pulp density of 175 g/L, and temperature of 100 °C for 1 h, yielding maximum efficacy. Subsequently, in the second step, the optimal conditions for cobalt leaching from the alkali-treated residue were established as follows: 2.0 M H2SO4, 25 g/L pulp density, and 75 °C temperature for 30 min. Downstream processing of the obtained metal ions in solutions was also easier, as the only impurity of dicobaltite ions with the Na2WO4 solution was precipitated as Co(OH)3 under atmospheric O2; meanwhile, the CoSO4 solution obtained through the second step of processing can be treated via electrolysis to recover the metallic cobalt. The present process is simpler in operation, and the efficient use of eco-friendly lixiviants eliminates the previously reported disadvantage.

  12. A study of thermal spray coated surface with nano composite powder of CNT+WC14C0

    Science.gov (United States)

    Balan, K. N.; Valarmathi, T. N.; Nuttaki, Akhil; Sai Vivek Reddy, Arani; Sai Srinivas, Jammalamadaka K. M. K.; Nathanael, M. Antony

    2016-09-01

    Coatings obtained from thermal spray process are being developed for wide varieties of applications in aerospace and automotive industries. To enhance the wear resistance in the YAWING in wind mills, a new study is required to find out and analyze the surface properties of the surface of Yawing. In this study to enhance the surface properties, a new nano composite powder has been developed and coated on SS304. To synthesis of CNT+WC14Co, initially a binder material of 0.5% Poly Vinyl alcohol solution was prepared and made use as a binder between CNT and WC14Co particles. The synthesized nano composite powder is coated over SS304 samples as per Taguchi design of experiments by Detonation gun coating technique. The coated samples are undergone the tests of micro hardness and Surface roughness. It was found that a significant improvement in micro hardness and there is no significant improvement in surface finish. The best combination of input parameters is obtained through Taguchi method and untried combination's results also have been predicted through Taguchi method. Response surface methodology (RSM) is used to develop a mathematical model.

  13. Influence of powder and spray parameters on erosion and corrosion properties of HVOF sprayed WC-Co-Cr coatings

    Energy Technology Data Exchange (ETDEWEB)

    Berget, John

    1998-07-01

    Thermal spraying is a generic term including various processes used to deposit coatings on surfaces. The coating material is in the form of powder or a wire and is melted or softened by means of a heat source. A gas stream accelerates the material towards a prepared surface and deposits it there to form the coating. Examples of components being maintained by application of thermal spray coatings are gate valves and ball valves for the offshore industry and turbine blades in power generations installations. Recent investigation has shown that the commonly used coating material WC-Co is not corrosion resistant. But it can be improved by the addition of Cr. The main objective of this thesis is to study the influence of spray process control variables and powder characteristics on the erosion and erosion-corrosion properties of the coatings. Spray process variables investigated include energy input, powder feed rate and spray distance. Powder characteristics studied are average size of the WC particles, relative proportions of Co and Cr in the metal phase and powder grain size distribution.

  14. Abrasive Wear Behavior of WC Reinforced Ni-BASED Composite Coating Sprayed and Fused by Oxy-Acetylene Flame

    Science.gov (United States)

    Wang, Qun; Chen, Zhenhua; Ding, Zhang Xiong; Chen, Ding

    Microstructure of WC reinforced Ni-based self-fluxing alloy composite coating sprayed and fused by oxy-acetylene flame was investigated by scanning electron microscopy and energy dispersive X-ray Spectrometry, X-ray diffraction, and transmission electron microscopy. The wear performance of the coating was studied by a MLS-225 wet sand rubber wheel abrasive wear tester at various loads and sizes of abrasive particles. Also, the wear resistance of the coating was compared with uncoated ASTM1020 steel. The results indicated that the coating is bonded metallurgically to the substrate and has a homogeneous microstructure composed of both coarse WC and fine carbide and boride grains such as Cr7C3, Cr23C6, and Ni2B which disperse uniformly in the matrix of γ-Ni solid solution and Ni3B. The worn mass loss of the coating and ASTM1020 steel both increased with the load and size of abrasive particles, also, the coating has exhibited excellent abrasive wear resistance compared with ASTM1020 steel.

  15. The role of La2O3 in direct laser sintering of submicrometre WC Cop/Cu MMCs

    Science.gov (United States)

    Gu, Dongdong; Shen, Yifu

    2008-05-01

    This paper presents a detailed investigation of the influence of rare earth (RE) oxide (La2O3) addition on densification and microstructure of direct laser sintered submicrometre WC-Cop/Cu metal matrix composites (MMCs) possessing 50.0 wt% reinforcement (WC-Co). It was found that with increasing La2O3 addition to a suitable amount (1.0 wt%), the particulate dispersion was homogenized and the particulate/matrix interfacial bonding was improved. However, with an excessive addition of La2O3 (1.5 wt%), a heterogeneous microstructure consisting of highly accumulated particulates was present. The exact metallurgical roles of RE element in direct laser sintering of particulate reinforced MMCs were addressed. It showed that a proper addition of RE element (i) decreased surface tension of the melt and enhanced solid-liquid wettability; (ii) dragged and/or pinned grain/phase boundaries and resisted grain coarsening and particulate aggregating. However, the balling phenomenon occurred and the activity of RE atoms decreased at an even higher La2O3 content, thereby producing detrimental effects on laser forming ability.

  16. Sliding friction of nanocomposite WC1-x/C coatings: transfer film and its influence on tribology.

    Science.gov (United States)

    Liu, Y; Gubisch, M; Spiess, L; Schaefer, J A

    2009-06-01

    The transfer film on steel spheres formed in reciprocating sliding against nanocomposite coatings based on nanocrystalline WC1-x in amorphous carbon matrix is characterized and correlated with the tribological properties measured by a precision microtribometer. With the presence of transfer film, a coefficient of friction approximately 0.13 and a depth wear rate approximately 0.35 x 10(-10) m/N.Pass were obtained. The central zone of the transfer film covering approximately 25% of the Hertz contact area is intact while cracks and wear debris are found in the vast peripheral area. It is also heavily oxidized due to the absence of carbon, which is located at the peripherals and acts as lubricants. We propose that the oxidation of WC and adhesion of the oxides to the surface of sphere is the main mechanism for the buildup of the transfer films. With the thickening of the film, the internal stress increases. Under the shear stress, spalling and cracking of the transfer film take place. The overall tribological performance of the coatings is therefore a competing process of buildup and spalling of transfer films.

  17. Advanced WC-Co cermet composites with reinforcement of TiCN prepared by extended thermal plasma route

    Energy Technology Data Exchange (ETDEWEB)

    Mondal, B. [Centre for Advanced Materials Processing, Central Mechanical Engineering Research Institute, Mahatma Gandhi Avenue, Durgapur 713 209, West Bengal (India)], E-mail: bnmondal@rediffmail.com; Das, P.K. [Central Glass and Ceramic Research Institute, Kolkata (India); Singh, S.K. [Institute of Minerals and Materials Technology (IIMT), Bhubeneswar (India)

    2008-12-20

    The synthesis of titanium carbonitride (TiCN) powders by thermal plasma using extended arc thermal plasma reactor and the effect of TiCN reinforcement for the development of advanced WC-Co cermets has been studied with respect to hardness and fracture toughness. These classes of materials are being investigated for future application in wear-resistant seals, cutting tools, etc. Metallurgical reactions and microstructural developments during sintering of cermets and functionally graded cemented carbonitrides are being investigated by analytical methods such as differential thermal analysis/thermo-gravimetric analysis, X-ray diffraction and analytical Scanning electron microscopy with energy dispersive X-ray spectroscopy. By an in-depth understanding of the complex phase reactions and the mechanisms that govern the sintering process and metallurgical reactions, new cermets and different types of functionally graded cemented carbonitrides with desired microstructures and properties have been attempted to develop. The significant improvement of micro-hardness was observed with optimal concentration of TiCN reinforcement addition in WC-Co system without sacrificing much fracture toughness value of the composite cermets.

  18. Microstructure and Properties of DCP-Derived W-ZrC Composite Using Nontoxic Sodium Alginate to Fabricate WC Preform

    Science.gov (United States)

    Najafzadeh Khoee, Ali Asghar; Habibolahzadeh, Ali; Qods, Fathallah; Baharvandi, Hamidreza

    2015-04-01

    In the present work, tungsten carbide (WC) preforms were fabricated by gel-casting process, using different nontoxic Na-alginate to tertiary calcium phosphate ratios and different loadings of WC powder in the initial slurries. The gel-cast green bodies were dried and pre-sintered at 1723 K for 4 h and then reactively infiltrated by molten Zr2Cu at 1623 K for 0.5 h, to produce W-ZrC composite via displacive compensation of porosity process. The phases, microstructures, and mechanical properties of the preforms and the W-ZrC composites were investigated by Fourier transform infrared spectroscope, x-ray diffractometer (XRD), scanning electron microscope (SEM), image analyzer, and universal mechanical testing machine. XRD results, SEM micrographs, and elemental maps indicated uniform distribution of phases (W and ZrC) and elements (W, Zr, and C). Flexural strengths and hardness of the fabricated composites were in the ranges of 429-460 MPa and 7.5-9.5 GPa, respectively. Fractography studies revealed two types of dimple rupture and cleavage fracture modes in different composite samples. The W-ZrC composite was ablated by an oxyacetylene flame for 60 s. The mean value of mass and linear ablation rates of the composite were 2.1 ± 0.1 mg/s and 3.6 ± 0.5 µm/s, respectively.

  19. MICROSTRUCTURE AND MECHANICAL PROPERTIES OF ULTRAFINE WC/Co CEMENTED CARBIDES WITH CUBIC BORON NITRIDE AND Cr₃C₂ ADDITIONS

    Directory of Open Access Journals (Sweden)

    Genrong Zhang

    2016-03-01

    Full Text Available This study investigates the microstructure and mechanical properties of ultrafine tungsten carbide and cobalt (WC/Co cemented carbides with cubic boron nitride (CBN and chromium carbide (Cr₃C₂ fabricated by a hot pressing sintering process. This study uses samples with 8 wt% Co content and 7.5 vol% CBN content, and with different Cr₃C₂ content ranging from 0 to 0.30 wt%. Based on the experimental results, Cr₃C₂ content has a significant influence on inhibiting abnormal grain growth and decreasing grain size in cemented carbides. Near-full densification is possible when CBN-WC/Co with 0.25 wt% Cr₃C₂ is sintered at 1350°C and 20 MPa; the resulting material possesses optimal mechanical properties and density, with an acceptable Vickers hardness of 19.20 GPa, fracture toughness of 8.47 MPa.m1/2 and flexural strength of 564 MPa.u̇ Å k⃗

  20. WC含量对CuZnAl表面Ni-P-WC复合镀层耐磨性的影响%Effect of WC content on wear properties of electrolees Ni-P-WC composite coating on surface of CuZnAl alloy

    Institute of Scientific and Technical Information of China (English)

    刘爱莲; 毛楠楠; 徐家文

    2015-01-01

    为提高材料的表面硬度和耐磨性,采用化学复合镀在CuZnAl合金表面制备不同WC含量的Ni-P-WC复合镀层,通过扫描电子显微镜观察分析复合镀层的微观形貌,测试复合镀层的耐磨性和显微硬度,分析WC含量对镀层耐磨性的影响规律。结果表明:当镀液中WC的质量浓度为30 g/L时,复合镀层呈均匀的胞状结构和优异的耐磨性。%This paper is motivated by the need for improving the surface hardness and wear resistance of CuZnAl alloy. This study does so by depositing Ni-P-WC composite coating containing different content of WC particles on the surface of CuZnAl shape memory alloys using electroless coating;investigating the microstructure, phase constitutent, microhardness and wear properties of Ni-P-WC composite coating by X-ray diffraction, scanning electron microscope and energy dispersive spectrum; and above all, testing the microhardness and wear properties of Ni-P-WC composite coating by microhardness testing machine and friction wear testing machine and thereby analyzing the effect of WC content. The results show that the Ni-P-WC composite coating is crystal state and boasts a better bonding the matrix well and the homog-enous coating thickness;as in the case of WC content of 30 g/L, WC particles disperse in the coating, thus giving the composite coating a fine cell morphology and the best wear resistance.

  1. Effect of Modified Atmosphere Packaging on Microbiological ...

    African Journals Online (AJOL)

    phrases: Modified atmosphere packaging, polypropylene, low density polyethylene ..... data from two packs pre treatment; mean separation by Duncan's Multiple Range Test at value 1%. ..... communities of lrltltiopia. ltlast Africa Medical. Journal ...

  2. A distance regular graph of type E1 Ed

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    In this note, the distance regular graph of type E1 Ed is considered and some characterization of the type graph is given. The results generalize the characterization of tight distance regular graphs.

  3. Elementi ed esercizi di geometria analitica e proiettiva

    CERN Document Server

    Francia, Giovanni

    1950-01-01

    La retta : preliminario ; coordinate cartesiane nel piano, equazioni della retta, distanze ed angoli ; cambiamento delle coordinate, coordinate polari ; il cerchio ; le coniche come luoghi geometrici : l'ellisse, l'iperbole, parabola.

  4. Nuclear Medicine Physics: The Basics. 7th ed.

    Science.gov (United States)

    Mihailidis, Dimitris

    2012-10-01

    Nuclear Medicine Physics: The Basics. 7th ed. Ramesh Chandra, Lippincott Williams and Wilkins, a Wolters Kluwer Business. Philadelphia, 2012. Softbound, 224 pp. Price: $69.99. ISBN: 9781451109412. © 2012 American Association of Physicists in Medicine.

  5. Examining practical nursing experiences to discover ways in which to retain and invigorate the remaining functions of the elderly with a demented and complex disability in nursing homes.

    Science.gov (United States)

    Park, Min-Sun; Lim, Sun-Young; Kim, Eun-Young; Lee, Su-Jung; Chang, Sung-Ok

    2017-05-23

    The bedridden elderly with moderate-to-severe dementia account for a large proportion of the residents in nursing homes and form a specialized group requiring customized care in order to encourage their remaining functions, which determine the quality of their residual life. The purpose of this study was to search for ways to invigorate and foster the remaining functions of this complex-disability group, based on practical nursing strategies in nursing homes. The qualitative thematic analysis was done by conducting in-depth interviews with 29 nurses working at 11 different nursing homes in South Korea. This study proposed four main themes and 19 sub themes as keys for providing specialized nursing care to the elderly with physical and cognitive disabilities. The main themes encourage the residents' remaining functions: (i) accurate identification of an elderly resident's physical, cognitive, and behavioral baseline is necessary in order to determine their functional levels; (ii) nurses provide meticulous management to support the remaining functions in order to prevent further deterioration; (iii) optimized know-how, based on accumulated experience and knowledge, is reflected in nursing strategies that maximize the effects of nursing interventions; and (iv) steady compliance with nursing guidelines and standards in nursing homes creates the best therapeutic environment and brings unexpected positive changes in the elderly's status. A practical nursing strategy to target the group with a demented and complex disability in nursing homes was developed through thematic analysis of the empirical knowledge of nurses. The findings provide new insights for developing specialized nursing interventions and practical nursing models in long-term care facilities. © 2017 Japan Academy of Nursing Science.

  6. Prevalence of nutritional risk in the non-demented hospitalised elderly: a cross-sectional study from Norway using stratified sampling.

    Science.gov (United States)

    Eide, Helene K; Šaltytė Benth, Jūratė; Sortland, Kjersti; Halvorsen, Kristin; Almendingen, Kari

    2015-01-01

    There is a lack of accurate prevalence data on undernutrition and the risk of undernutrition among the hospitalised elderly in Europe and Norway. We aimed at estimating the prevalence of nutritional risk by using stratified sampling along with adequate power calculations. A cross-sectional study was carried out in the period 2011 to 2013 at a university hospital in Norway. Second-year nursing students in acute care clinical studies in twenty hospital wards screened non-demented elderly patients for nutritional risk, by employing the Nutritional Risk Screening 2002 (NRS2002) form. In total, 508 patients (48·8 % women and 51·2 % men) with a mean age of 79·6 (sd 6·4) years were screened by the students. Mean BMI was 24·9 (sd 4·9) kg/m(2), and the patients had been hospitalised for on average 5·3 (sd 6·3) d. WHO's BMI cut-off values identified 6·5 % as underweight, 48·0 % of normal weight and 45·5 % as overweight. Patients nutritionally at risk had been in hospital longer and had lower average weight and BMI compared with those not at risk (all P nutritional risk was estimated to be 45·4 (95 % CI 41·7 %, 49·0) %, ranging between 20·0 and 65·0 % on different hospital wards. The present results show that the prevalence of nutritional risk among elderly patients without dementia is high, suggesting that a large proportion of the hospitalised elderly are in need of nutritional treatment.

  7. Slurry Erosion Performance Study of Detonation Gun-Sprayed WC-10Co-4Cr Coatings on CF8M Steel Under Hydro-Accelerated Conditions

    Science.gov (United States)

    Bhandari, Sanjeev; Singh, Harpreet; Kumar, Harmesh; Rastogi, Vikas

    2012-09-01

    In the current investigation, cermet coatings (WC-10Co-4Cr) were deposited on CF8M steel by detonation gun (D-gun) thermal spraying process. Subsequently, the slurry erosion behaviors of the coated and bare steels were investigated using a high-speed erosion test rig. Slurry collected from an actual hydro power plant was used as the abrasive media. Effects of concentration (ppm), average particle sizes and rotational speed on the slurry erosion behaviors of coated and bare steels under different experimental conditions were studied. The analysis of eroded samples was done using SEM and stylus profilometry. Signatures of microcutting, fracture of well-bonded WC grains, and fragmentations were observed on the eroded surface of WC-10Co-4Cr coating, while signatures of formation of plowing, lips, shearing of platelet, formation of crater, and micro-cutting were observed on the eroded surface of CF8M steel.

  8. Slurry Erosion Behavior of F6NM Stainless Steel and High-Velocity Oxygen Fuel-Sprayed WC-10Co-4Cr Coating

    Science.gov (United States)

    Cui, S. Y.; Miao, Q.; Liang, W. P.; Huang, B. Z.; Ding, Z.; Chen, B. W.

    2017-02-01

    WC-10Co-4Cr coating was applied to the surface of F6NM stainless steel by high-velocity oxygen-fuel spraying. The slurry erosion behavior of the matrix and coating was examined at different rotational speeds using a self-made machine. This experiment effectively simulates real slurry erosion in an environment with high silt load. At low velocity (<6 m/s), the main failure mechanism was cavitation. Small bubbles acted as an air cushion, obstructing direct contact between sand and the matrix surface. However, at velocity above 9 m/s, abrasive wear was the dominant failure mechanism. The results indicate that WC-10Co-4Cr coating significantly improved the slurry resistance at higher velocity, because it created a thin and dense WC coating on the surface.

  9. Research on Ultrafine Tungsten Carbide-Cobalt (WC-Co) Cemented Carbide Rods of Miniature Drills for Highly Integrated Printed Circuit Board (PCB)

    Institute of Scientific and Technical Information of China (English)

    Xiaoliang SHI; Gangqin SHAO; Xinglong DUAN; Runzhang YUAN

    2005-01-01

    Nanocrystalline tungsten carbide-cobalt (WC-Co) composite powders produced through spray thermal decomposition-continuous reduction and carburization technology were used to prepare φ3.25 mm ×38 mm ultrafine tungsten carbidecobalt (WC-Co) cemented carbide rods through vacuum sintering plus sinterhip technology. The microstructure,Vickers hardness, density and Rockwell A hardness (HRA), transverse rupture strength (TRS), saturated magnetization and coercivity force were tested. The results show that the average grain size of the sintering body prepared through vacuum sintering plus sinterhip technology was 430 nm; transverse rupture strength (TRS) was 3850 MPa;Vickers hardness was 1890 and Rockwell A hardness of sintering body was 93. High strength and high hardness ultrafine WC-Co cemented carbide rods used to manufacture printed circuit board (PCB) drills were obtained.

  10. Safe Handling of Snakes in an ED Setting.

    Science.gov (United States)

    Cockrell, Melanie; Swanson, Kristofer; Sanders, April; Prater, Samuel; von Wenckstern, Toni; Mick, JoAnn

    2017-01-01

    Efforts to improve consistency in management of snakes and venomous snake bites in the emergency department (ED) can improve patient and staff safety and outcomes, as well as improve surveillance data accuracy. The emergency department at a large academic medical center identified an opportunity to implement a standardized process for snake disposal and identification to reduce staff risk exposure to snake venom from snakes patients brought with them to the ED.

  11. DISTRIBUZIONE, TASSONOMIA ED IMPATTO ECOLOGICO DI SPECIE ALIENE

    OpenAIRE

    Stinca, Adriano

    2013-01-01

    Il problema delle specie aliene, soprattutto negli ultimi decenni, è diventato un elemento cruciale nella biologia della conservazione. La diffusione rapida ed incontrollata di organismi estranei al contesto territoriale di riferimento, infatti, spesso comporta impatti sulla biodiversità e sul funzionamento degli ecosistemi. In tali casi, pertanto, vi è anche l’incapacità da parte degli stessi sistemi biologici invasi a ristabilire autonomamente ed in tempi relativamente brevi le condizioni i...

  12. Effects of Oxygen-fuel Ratio on Structure and Property of Detonation Gun Sprayed WC Coating

    Directory of Open Access Journals (Sweden)

    ZHAO Li-ying

    2016-06-01

    Full Text Available The tungsten carbide coating with both high hardness and dense microstructure was prepared by optimizing the detonation gun spraying parameters. The phase identifications and microstructure of the coating were observed and analyzed by optical microscope, X-ray diffraction (XRD and energy dispersive spectrometer (EDS. The results show that with the increase of oxygen-fuel ratio, the hardness and adhesive strength of the coating firstly enhance and then decrease, while porosities firstly decrease and then increase. When the oxygen fuel ratio is too low, slow particle flight speed and insufficient melt are the main reasons for the degradation of the coating compactness and mechanical properties. When the oxygen fuel ratio is too high, particle decarburization and binder phase nonuniform contract in the cooling process are the determining factors to the coating structure and properties. When the oxygen-fuel ratio is 1.15, comprehensive performance of the coating is optimal, and the oxidation and decarburization of the coating can be effectively reduced. The Vickers microhardness HV0.3 of cross-section reaches 1178kg·mm-2, the porosity is 0.86%, and the bonding strength between the coating and substrate is 152MPa.

  13. 超重力辅助燃烧合成熔渗梯度Ni-(WC-Ni)硬质合金复合材料%Fabrication of gradient WC-Ni cemented carbide materials by high-gravity-assisted combustion synthesis and infiltration

    Institute of Scientific and Technical Information of China (English)

    杨增朝; 刘光华; 徐利华; 郭世斌; 李江涛

    2013-01-01

    以超重力辅助燃烧合成熔渗工艺制备了具有梯度特征的 WC-Ni 硬质合金材料。该工艺以铝热反应为基础,施加辅助超重力场,制备出具有梯度特征的硬质合金材料。该材料具有双层梯度结构:沿重力场方向依次为Ni金属层和 WC-Ni硬质合金层。其中Ni金属层的硬度值为72HRA;硬质合金层的硬度值最高为87HRA。Ni熔体在熔渗过程中的搅动使 WC在Ni金属层出现弥散分布并导致硬质合金层 WC 的长大。熔体由底层开始向顶层逐渐凝固的特点使该梯度材料抗弯强度降低。%Gradient WC-Ni cemented carbide materials were prepared by high-gravity-assisted combustion syn-thesis and infiltration,where Ni melt was in-situ synthesized and then infiltrated into porous compacts of WC powder.The obtained materials consisted of two layers and showed a gradient feature along the high-gravity di-rection,in which the upper layer was Ni metal and the under layer was WC-Ni cemented carbide.The hardness of the Ni metal and WC-Ni cemented carbide reached 72 HRA and 87 HRA,respectively.The agitation of Ni melt during infiltration resulted in the presence of WC particles in the Ni metal and growth of WC grains in the cemented carbide layer.The WC-Ni cemented carbide materials showed a relatively low bending strength of 770 MPa,which may be connected with the down-to-up solidification kinetics.

  14. Effect of high current pulsed electron beam treatment on wear resistance of WC-Co hard alloys%强流脉冲电子束处理对WC-Co硬质合金耐磨性的影响

    Institute of Scientific and Technical Information of China (English)

    任鑫; 曹丹凤; 徐洋; 郝胜智

    2015-01-01

    作为一种新型高效的表面改性技术,强流脉冲电子束( HCPEB)由于可以在极短时间内诱发的温度-应力耦合作用,改性层内组织细化并生成纳米新相WC1-x、Co3 W3 C、Co3 W9 C4和石墨,从而改善合金的理化性质以及力学性能等,达到表面强化的目的。本文研究了HCPEB表面改性处理后YG8、YG6X和YG6硬质合金耐磨性的变化情况。结果表明,23.4 kV、25次辐照处理后的YG8硬质合金耐磨性提高3倍;27 kV、20次辐照处理后YG6X的耐磨性提高6.4倍;27 kV、20次辐照处理后YG6硬质合金耐磨性提高4.4倍。 HCPEB处理后的WC-Co硬质合金的耐磨性均有明显提高。%High current pulsed electron beam has been proved to be an effective method for surface modification of materials in recent years. Along with the extremely high energy density deposition on the surface of material, the thermal and mechanical processes can make the rise of the non-equilibrium structure surface modification effect accompanied by the formation of a mixture of nano-grained WC1-x , Co3 W3 C, Co3 W9 C4 and graphite, and then the physical, chemical and mechanical properties were improved. The effect of high current pulsed electron beam treatment on wear resistance of WC-Co hard alloys coating such as YG8, YG6 and YG6X alloy was investigated. The results show that the YG8 hard alloy is used to modifying by 20 pulses high current pulsed electron beam under the condition of the accelerating voltage of 23. 4 kV, the wear resistance increases by a factor of 3 times compared with the original sample. After 20 pulses treatment by high current pulsed electron beam under the condition of the accelerating voltage of 27 kV, the wear resistance of the YG6 hard alloy raises by a factor of 6. 4 times, and the YG6X hard alloy’s wear resistance is increased by a factor of 4. 4 times.

  15. On Determination the Grain Size of Nano Crystalline WC-Co Hardmetals%纳米晶WC-Co硬质合金中WC晶粒度的评价方法

    Institute of Scientific and Technical Information of China (English)

    林晨光; 袁冠森; 王林山

    2004-01-01

    在改进的传统金相样品制备和Murakami侵蚀剂化学腐蚀条件下,场发射扫描电镜在10万倍放大倍率下可获得衬度良好、WC晶粒轮廓清晰的二次电子图像.用截线法定量测定了纳米晶WC-Co硬质合金中WC晶粒度,结果表明:在适当的工艺条件下,添加微量新型VC基复合晶粒生长抑制剂可获得纳米晶硬质合金:WC平均晶粒尺寸50nm,标准偏差14 nm,最大晶粒尺寸110 nm.

  16. Mechanical characterization of cemented carbide WC-6Co (%wt) manufactured by SPS (Spark Plasma Sintering; Caracterizacao mecanica de metal duro WC-6Co (%massa) sinterizado via SPS (Spark Plasma Sintering)

    Energy Technology Data Exchange (ETDEWEB)

    Boidi, G.; Tertuliano, A.J.; Machado, I.F., E-mail: guido.boidi@usp.br [Universidade de Sao Paulo (USP), SP (Brazil). Departamento de Engenharia Mecatronica e Sistemas Mecanicos; Rodrigues, D. [BRATS- Filtros Sinterizados e Pos Metalicos, Cajamar, SP (Brazil)

    2016-07-01

    This work aimed to manufacture cemented carbide (WC-6%wtCo) obtained by SPS (Spark Plasma Sintering) process and to carry out the mechanical characterization by hardness and fracture toughness. The material was consolidated at 1100 deg C for different holding times (1 min, 5 min, 10 min), in order to evaluate the densification. A reference sample was also used to be compared to SPS. Optical and scanning electron microscopy were carried out to characterize the microstructural features of the samples and mechanical properties were obtained by hardness measurements (micro and macro) and instrumented indentation. The fracture toughness was calculated with the method of Palmqvist. Best results were found in the material sintered by SPS for 10 minutes of holding time, in which 97% of relative density and about 1600 HV{sub 10} was reached. (author)

  17. Study of the sintering behavior of fine, ultrafine and nanocrystalline WC-CO mixtures obtained by high energy milling; Estudio del comportamiento durante la sinterizacion de mezclas WC-Co finas, ultrafinas y nanocristalinas obtenidas por molienda de alta energia

    Energy Technology Data Exchange (ETDEWEB)

    Salvador, M. D.; Bonache, V.; Amigo, V.; Busquets, D.

    2008-07-01

    In this work the sintering behaviour of fine, ultrafine and nanocrystalline WC-12Co mixtures obtained by high energy milling, as well commercial nano powders, have been studied, in order to evaluate the effect of the particle size and the powder processing, in the densification, microstructural development and mechanical properties of the final product. The consolidation of the mixtures has been made by uniaxial pressing and sintering in vacuum, and by hot isostatic pressing. The sintered materials have been evaluated by measures of density, hardness and indentation fracture toughness, and micro structurally characterized by optical microscopy and scanning and transmission electronic microscopy (SEM and TEM). The results show the improvements in resistant behaviour of the materials obtained from nanocrystalline powders, in spite of the grain growth experienced during the sintering. The best results were obtained for the milling nanocrystalline material, which presents values of hardness higher than 180 HV. (Author) 46 refs.

  18. Microstructure Transformation of WC-(Ti,W)C-(Ta,Nb)C-Co Sample during Sintering Process%WC-(Ti,W)C-(Ta,Nb)C-Co试样烧结过程中组织结构的变化

    Institute of Scientific and Technical Information of China (English)

    高跃红; 颜练武; 林江华; 左锐

    2014-01-01

    将成分为WC-5%(Ti,W)C-5%(Ta,Nb)C-6%Co的混合料在1 150、1 200、1 250、1 300、1 350、1 400、1 450℃不同的温度下烧结,保温30 min制备成烧结体.利用X射线衍射仪、扫描电镜及能谱仪研究各温度下烧结体的相成分和组织结构变化.研究结果表明:当烧结温度为1 150℃时,烧结体中存在四种物相:白色的WC,浅灰色的(Ta,Nb)C,深灰色棱角分明的(Ti,W)C和深灰色的Co相.当烧结温度升高到1 200℃时,(Ti,W)C和(Ta,Nb)C发生轻微的固溶反应形成(W,Ti,Ta,Nb)C相,WC向(Ti,W)C中扩散形成W含量更多的(Ti,W)C相.当温度升高到1 250℃时,(Ti,W)C相几乎消失,(Ta,Nb)C相进一步减少,形成大量的成分不均匀的(W,Ti,Ta,Nb)C相.当温度升高到1 300℃时,(W,Ti,Ta,Nb)C相的成分均匀化过程基本完成.当温度升高到1 350~1 450℃时,WC晶粒进一步长粗,烧结体中存在三个稳定的相:WC、(W,Ti,Ta,Nb)C、γ.

  19. MANY MEN USED ED TREATMENT WITHOUT THEIR PARTNERS’ KNOWLEDGE

    Directory of Open Access Journals (Sweden)

    Tan HM

    2007-01-01

    Full Text Available This paper aimed to identify and explore the understanding and perception of erectile dysfunction (ED using exploratory qualitative approaches. This study was conducted in Klang Valley, Malaysia. Purposive sampling was used to recruit 17 urban men aged 40-75 years. A semi-structural interview guide was used to explore men’s understanding of ED, impacts on their well-being and experiences with treatments. The focus groups revealed that ED was perceived to be an important loss in men’s lives as sexual performance was closely related to manhood. The men associated ED with a loss of masculinity and self-esteem. Men’s understanding of ED treatments was restricted to phophodiesterase type 5 inhibitors (PDE-5 inhibitors and traditional therapies. Although PDE-5 inhibitors were perceived to be effective, they were concerned about their safety and costs. Some of the men have learned to cope with ED rather than to seek help, particularly among older men, who attributed their decreased sexual capacities and erection difficulties to aging, and therefore conditioned themselves to accepting it. In contrast, younger men who have erectile difficulties are considered as ‘abnormal’, and are more likely to seek help and receive treatment for their sexual problem. Men’s knowledge of and experience with modern treatments of ED were mainly associated with PDE-5 inhibitors. Their perception towards PDE-5 inhibitors was largely influenced by personal experience, information from mass media and friends. The high cost and fear of side effects were two main deterrents in the use of PDE-5 inhibitors. Many men had conceded their use of PDE-5 inhibitors without their partners’ knowledge. They worried that their partners would view the matter with suspicion and mistrust.

  20. Small d-spacing WC/SiC multilayers for future hard X-ray telescope designs

    DEFF Research Database (Denmark)

    Jensen, C.P.; Madsen, K.K.; Christensen, Finn Erland

    2005-01-01

    interfacial roughness. With the new material combinations of WC/SiC the interface roughness can be reduced down to between 0.23 nm and 0.25 nm enabling bi-layer thicknesses down to 1.0 nm to reflect efficiently. The production of thinner period coatings thus enables the possibility for focusing optic designs......Multilayer coatings for reflecting hard X-rays up to 80keV, like W/Si and Pt/C, have been studied for several years. To go to higher energies, in the range of 100 keV to 250 keV, one needs coatings with smaller d-spacings than can currently be made with these material combinations, and a lower...

  1. High temperature oxidation of WC-CrN Nano-multilayered film at 700 and 800 degrees C.

    Science.gov (United States)

    Lee, Dong-Bok

    2009-12-01

    Nano-multilayered WC-CrN films were deposited onto steel substrates by an arc ion plating method. The oxidation characteristics of the films were studied at 700 and 800 degrees C for up to 60 h in air. In each case, during oxidation, carbon and nitrogen escaped from the film into the air, while oxygen from the air diffused into the film. Substrate elements diffused outwards towards the oxide surface. The high-temperature oxidation resistance was not satisfactory, mainly due to the formation of a non-protective, volatile W-oxide scale, and the escape of carbon and nitrogen from the film. The scale formed was prone to cracking and spallation. The oxidation resulted in the destruction of the original nano-multilayers.

  2. Behavior of HVOF WC-10Co4Cr Coatings with Different Carbide Size in Fine and Coarse Particle Abrasion

    Science.gov (United States)

    Ghabchi, Arash; Varis, Tommi; Turunen, Erja; Suhonen, Tomi; Liu, Xuwen; Hannula, S.-P.

    2010-01-01

    A modified ASTM G 65 rubber wheel test was employed in wet and dry conditions using 220 nm titania particles and 368 μm sand particles, respectively. Both tests were conducted on WC-CoCr coatings produced with two powders with different carbide grain sizes (conventional and sub-micron) to address the effect of carbide size and abrasive medium characteristics on the wear performance. The same spot before and after the wet abrasion wear testing was analyzed in detail using SEM to visualize wear mechanisms. It was shown that the wear mechanism depends on the relative size of the carbide and abrasive particles. Wear mechanisms in dry sand abrasion were studied by analyzing the single scratches formed by individual abrasive particles. Interaction of surface open porosity with moving abrasive particles causes formation of single scratches. By tailoring the carbide size, the wear performance can be improved.

  3. Glycemic index and glycemic load of thirteen year old children whose waist circumference (WC ≥ 90 percentile dependent on BMI

    Directory of Open Access Journals (Sweden)

    Zuzanna Goluch-Koniuszy

    2011-06-01

    Full Text Available Background. One of the reasons for the accumulation of fat tissue (including visceral fat tissue in the body is an unbalanced diet in respect of the amount and the structure of carbohydrates and the value of the glycemic index (GI and the glycemic load (GL. The research describing the dependence between the BMI (Body Mass Index, WC (Waist Circumference, WHtR (Waist-to-Height Ratio, and GI and GL indexes in adults exists but only a limited number of works discuss children during the pubertal spurt. Therefore the objective of this research is the evaluation of the state of nutrition of 13-year-old children with waist circumference ≥ 90 percentile with various BMI, taking into consideration GL and GL of their meals. Material and methods.The state of nutrition (BMI, WC, WHtR of 871 thirteen-year-old children of both sexes was evaluated and 230 children with WC ≥ 90 percentile were selected (26.4% of the total number examined and divided into three groups regarding the BMI. In 71 children (30.9% of the selected group the method of nutrition, energy and nutritive value of menus, structure of consumption of food groups and GI and GL value were evaluated, on the basis of the analysis of their three day menus, which had been documented. Results.Significantly higher values of BMI and WC were ascertained in boys than in girls. No essential differences in values of WHtR index were ascertained between boys and girls. The analysis of children’s menus, in both sexes with a waist circumference ≥ 90 percentile showed, regardless of BMI value, a low realisation of recommended energetic value of the diet and low realisation of recommended supply of: dietary fibre, fat, mineral components (K, Ca, P, Mg, Fe, Zn, Cu, vitamins (E, B1, PP and liquids with simultaneous occurrence of protein in general and animal protein, sodium and vitamins (A, B2, B6 supply. A significantly higher supply of the most of aforementioned ingredients was ascertained in the

  4. Phase-field simulation of liquid phase migration in the WC-Co system during liquid phase sintering

    Energy Technology Data Exchange (ETDEWEB)

    Cheng, Kaiming; Zhang, Lijun; Du, Yong [Central South Univ., Changsha (China). State Key Lab. of Powder Metallurgy; Schwarze, Christian; Steinbach, Ingo [Bochum Univ. (Germany). Interdisciplinary Centre for Advanced Materials Simulation

    2016-04-15

    Liquid phase sintering is a process for forming high performance, multiple-phase components from powders. The process includes very complex interactions between various mass transportation phenomena, among which the liquid phase migration represents an important one in the aspect of forming a gradient structure in cemented carbide. In the present work, phase-field simulation of the liquid phase migration phenomenon during liquid phase sintering is performed in the WC-Co based cemented carbide. The simulation results are analyzed and compared with the experimentally determined key factors of microstructural evolution, such as contiguity and liquid phase migration rate. The diffusion-controlled solution-precipitation mechanism of the liquid phase migration process in the cemented carbide system is confirmed from the current simulation result, which provides deeper understanding of the microstructural evolution during the liquid phase migration process. These simulations can offer guidance in preventing the liquid phase migration process during liquid phase sintering of cellular cemented carbide.

  5. Chick embryo proliferation studies using EdU labeling.

    Science.gov (United States)

    Warren, Michelle; Puskarczyk, Karolina; Chapman, Susan C

    2009-04-01

    Cell proliferation studies are an important experimental tool. The most commonly used thymidine analogues, tritiated thymidine and bromodeoxyuridine (BrdU) label cells during S-phase. Both methods have significant drawbacks: low sensitivity in the case of tritiated thymidine and a denaturation step during BrdU detection that destroys most cellular epitopes, requiring careful optimization. The antibody against BrdU is also large and tissue penetration can be difficult. EdU (5'-ethynyl-2'-deoxyuridine) is closely chemically related to BrdU, with detection achieved by a copper catalyzed reaction requiring a small fluorescently conjugated azide. Cell cultures, flow cytometry and high throughput studies using EdU-labeled cells is exceptionally fast and does not require denaturation or antibodies. We have developed a tissue-labeling technique in chick embryos using EdU. Following EdU chemistry to detect proliferating cells, the tissue can undergo immunolabeling. We demonstrate fluorescent EdU chemistry followed by Tuj1 antibody staining resulting in multiplex fluorescent tissues.

  6. Effect of SiC Nanowhisker on the Microstructure and Mechanical Properties of WC-Ni Cemented Carbide Prepared by Spark Plasma Sintering

    Directory of Open Access Journals (Sweden)

    Xiaoyong Ren

    2014-01-01

    Full Text Available Ultrafine tungsten carbide-nickel (WC-Ni cemented carbides with varied fractions of silicon carbide (SiC nanowhisker (0–3.75 wt.% were fabricated by spark plasma sintering at 1350°C under a uniaxial pressure of 50 MPa with the assistance of vanadium carbide (VC and tantalum carbide (TaC as WC grain growth inhibitors. The effects of SiC nanowhisker on the microstructure and mechanical properties of the as-prepared WC-Ni cemented carbides were investigated. X-ray diffraction analysis revealed that during spark plasma sintering (SPS Ni may react with the applied SiC nanowhisker, forming Ni2Si and graphite. Scanning electron microscopy examination indicated that, with the addition of SiC nanowhisker, the average WC grain size decreased from 400 to 350 nm. However, with the additional fractions of SiC nanowhisker, more and more Si-rich aggregates appeared. With the increase in the added fraction of SiC nanowhisker, the Vickers hardness of the samples initially increased and then decreased, reaching its maximum of about 24.9 GPa when 0.75 wt.% SiC nanowhisker was added. However, the flexural strength of the sample gradually decreased with increasing addition fraction of SiC nanowhisker.

  7. Effectiveness and economic analysis of the whole cell/recombinant B subunit (WC/rbs inactivated oral cholera vaccine in the prevention of traveller's diarrhoea

    Directory of Open Access Journals (Sweden)

    Diez-Diaz Rosa

    2009-05-01

    Full Text Available Abstract Background Nowadays there is a debate about the indication of the oral whole-cell/recombinant B-subunit cholera vaccine (WC/rBS in traveller's diarrhoea. However, a cost-benefit analysis based on real data has not been published. Methods A cost-effectiveness and cost-benefit study of the oral cholera vaccine (WC/rBS, Dukoral® for the prevention of traveller's diarrhoea (TD was performed in subjects travelling to cholera risk areas. The effectiveness of WC/rBS vaccine in the prevention of TD was analyzed in 362 travellers attending two International Vaccination Centres in Spain between May and September 2005. Results The overall vaccine efficacy against TD was 42,6%. Direct healthcare-related costs as well as indirect costs (lost vacation days subsequent to the disease were considered. Preventive vaccination against TD resulted in a mean saving of 79.26 € per traveller. Conclusion According to the cost-benefit analysis performed, the recommendation for WC/rBS vaccination in subjects travelling to zones at risk of TD is beneficial for the traveller, regardless of trip duration and visited continent.

  8. Community-based assessment of safety and immunogenicity of the whole cell plus recombinant B subunit (WC/rBS) oral cholera vaccine in Peru.

    Science.gov (United States)

    Begue, R E; Castellares, G; Ruiz, R; Hayashi, K E; Sanchez, J L; Gotuzzo, E; Oberst, R B; Taylor, D N; Svennerholm, A M

    1995-05-01

    Every year since its introduction in 1991, there have been epidemics of cholera in Lima, Peru. Vaccination is one approach to the control of cholera. A pilot study was conducted to assess the safety and immunogenicity of a whole cell plus recombinant B subunit (WC/rBS) cholrea vaccine in Lima, Peru. Five hundred and forty-one volunteers aged 2-65 years received two doses two weeks apart of WC/rBS vaccine or Escherichia coli K12 placebo administered in bicarbonate buffered water. Symptoms were monitored on all subjects and blood was collected from 102 persons before the first dose and two weeks after the second dose. Mild post-vaccination gastrointestinal symptoms were reported with equal frequency for both the vaccine and placebo recipients. Among 51 vaccines, 49% had a twofold or greater increase in serum vibriocidal titers (GMT = 78; range < 1:10 to 1:5120); and 92% and 82% developed a twofold or greater serum anti-cholera toxin IgG and IgA response, respectively. Persons with elevated prevaccination vibriocidal titers had a decreased response to the WC/rBS. Age and blood group did not affect the immune response. The WC/rBS vaccine was safe and immunogenic in a group of native Peruvians.

  9. Safety and Immunogenicity of an Inactivated Whole Cell Plus Recombinant B Subunit (WC/RBS) Cholera Vaccine in Healthy Adult Peruvian Military Volunteers.

    Science.gov (United States)

    1992-11-30

    AD-A260 586 IFB0 919931 MIPR NO: 92MM2532W TITLE: SAFETY AND IMMUNOGENICITY OF AN INACTIVATED WHOLE CELL PLUS RECOMBINANT B SUBUNIT (WCIRBS) COLERA ...NUMBERS Safety and Immunogenicity of an Inactivated Whole MIPR No. Cell Plus Recombinant B Subunit (WC/RBS) Colera 92MM2532 Vaccine in Healthy Adult

  10. Thermodynamic Analysis and Synthesis of Fine WC Powder in the WO3-CH4-H2 System Using Excessive CH4

    Science.gov (United States)

    Cetinkaya, S.; Eroglu, S.

    2017-10-01

    This study aims to investigate reaction behavior of WO3 powder in H2-CH4 flow using excessive CH4 with respect to the oxide at 900-1300 K for 60 min and 120 min. Mass measurement, x-ray diffraction and scanning electron microscopy techniques were used to characterize the products. The oxide reduction occurred prior to the carburization possibly owing to high H2 diffusivity. WC formation significantly increased with temperature, but slightly with time. Incomplete carburization was observed at 900-1100 K, whereas single WC phase was attained at 1200 K and 1300 K for both reaction times. The thermodynamics predicted single WC phase at 900-980 K, and free C phase along with WC at 980-1300 K. The results have been discussed in terms of solid state C diffusivity, CH4 decomposition, CH4 residence time, defects and self-created local atmosphere. The mean particle size increased with temperature from 0.15 µm at 900 K to 1 µm at 1300 K.

  11. Empirical ranking of a wide range of WC-Co grades in terms of their abrasion resistance measured by the ASTM standard B 611-85 test

    CSIR Research Space (South Africa)

    O'Quigley, DGF

    1997-01-01

    Full Text Available This paper reports the results of a comprehensive investigation into the abrasion resistance of WC-Co alloys, as measured by the ASTM Standard B 611-85 test. The alloys ranged from 3 to 50 wt% and from 0.6 to 5 mu-m average grain size. Careful...

  12. Effect of SiC nanowhisker on the microstructure and mechanical properties of WC-Ni cemented carbide prepared by spark plasma sintering.

    Science.gov (United States)

    Ren, Xiaoyong; Peng, Zhijian; Fu, Zhiqiang; Wang, Chengbiao

    2014-01-01

    Ultrafine tungsten carbide-nickel (WC-Ni) cemented carbides with varied fractions of silicon carbide (SiC) nanowhisker (0-3.75 wt.%) were fabricated by spark plasma sintering at 1350°C under a uniaxial pressure of 50 MPa with the assistance of vanadium carbide (VC) and tantalum carbide (TaC) as WC grain growth inhibitors. The effects of SiC nanowhisker on the microstructure and mechanical properties of the as-prepared WC-Ni cemented carbides were investigated. X-ray diffraction analysis revealed that during spark plasma sintering (SPS) Ni may react with the applied SiC nanowhisker, forming Ni2Si and graphite. Scanning electron microscopy examination indicated that, with the addition of SiC nanowhisker, the average WC grain size decreased from 400 to 350 nm. However, with the additional fractions of SiC nanowhisker, more and more Si-rich aggregates appeared. With the increase in the added fraction of SiC nanowhisker, the Vickers hardness of the samples initially increased and then decreased, reaching its maximum of about 24.9 GPa when 0.75 wt.% SiC nanowhisker was added. However, the flexural strength of the sample gradually decreased with increasing addition fraction of SiC nanowhisker.

  13. Nano indentations studies of WC/C and TiN/(Ti,Al)N multilayer PVD coatings combined with cross-sectional electron microscopy observations

    NARCIS (Netherlands)

    Carvalho, NJM; De Hosson, JTM; Meng, WJ; Kumar, A; Doll, GL; Cheng, YT; Veprek, S; Chung, YW

    2001-01-01

    Multilayers of tungsten carbide/carbon (WC/C) with an amorphous structure and multilayers of titanium nitride/titanium-aluminum nitride (TiN/(Ti,Al)N) with a polycrystalline structure, prepared by physical vapor deposition, have been subjected to nanoindentation testing. The investigation has been a

  14. Reduction of electron channeling in EDS using precession.

    Science.gov (United States)

    Liao, Yifeng; Marks, Laurence D

    2013-03-01

    We demonstrated that EDS measurement can be significantly improved by precessing the electron beam, thereby reducing electron channeling effects. For a SrTiO3 specimen orientated along the [001] zone axis, the measured strontium to titanium atomic ratio was 0.74-0.80 using conventional EDS methods, and the ratio was improved to ~0.99 by precessing the electron beam for angles greater than 22.54 mRad. In ALCHEMI-like experiments in which the specimen was tilted to near two-beam condition, the strontium to titanium ratio was insensitive to the deviation from the Bragg condition using a precessed electron beam. Similar reduction of electron channeling effects was also observed in precession-assisted EDS measurements for an L21-ordered Fe2MnAl intermetallic alloy tilted to the [011] zone axis as well as near two-beam conditions.

  15. ED becomes 'lean' and cuts LBTC, LOS times.

    Science.gov (United States)

    2008-04-01

    Lean manufacturing techniques, first developed by Toyota, can be successfully adapted to help improve processes in your ED. St. Luke's Episcopal Hospital in Houston, has used Lean to reduce median length of stay, frequency of diversions, and the percentage of patients who left before treatment was complete (LBTC). Here's why "Lean" can help improve the performance of your ED: It enables you and your staff to see things from the patient's point of view. Lean tools enable you to view the status of your department in real-time and to compare that status with your performance goals. Exercises help identify areas where your processes break down and determine the most likely solutions.

  16. Reduction of Electron Channeling in EDS using Precession

    OpenAIRE

    Liao, Yifeng; Marks, Laurence D.

    2012-01-01

    We demonstrate that EDS measurement can be significantly improved by precessing the electron beam, thereby reducing electron channeling effects. For a SrTiO3 specimen orientated along [001] zone axis, the measured strontium to titanium atomic ratio was 0.74 – 0.80 using conventional EDS methods, and the ratio was improved to ~0.99 by precessing the electron beam for angles greater than 22.54 mRad. In ALCHEMI-like experiments in which the specimen was tilted to near two-beam condition, the str...

  17. New psych unit eases patient burden in ED.

    Science.gov (United States)

    2008-06-01

    Creating a special unit for psychiatric patients frees up beds in your ED, ensures better care for that patient population, and improves the atmosphere in the main department for the rest of your patients. Consider these suggestions: The creation of a psych unit can be extremely costly. Be prepared to demonstrate projected savings when pitching the idea to administration. Make sure an ED physician has overall responsibility for each patient at all times. Keep a regular group of nurses in rotation. This setup will help ensure smooth handoffs.

  18. Investigations of mussel-inspired polydopamine deposition on WC and Al{sub 2}O{sub 3} particles: The influence of particle size and material

    Energy Technology Data Exchange (ETDEWEB)

    Mondin, Giovanni, E-mail: giovanni.mondin@chemie.tu-dresden.de [Department of Inorganic Chemistry, Dresden University of Technology, Bergstrasse 66, 01069 Dresden (Germany); Haft, Marcel, E-mail: m.haft@ifw-dresden.de [Leibniz Institute for Solid State and Materials Research (IFW) Dresden, Institute for Solid State Research, Helmholtzstr. 20, 01069 Dresden (Germany); Wisser, Florian M., E-mail: florian.wisser@chemie.tu-dresden.de [Department of Inorganic Chemistry, Dresden University of Technology, Bergstrasse 66, 01069 Dresden (Germany); Leifert, Annika, E-mail: annika.leifert@chemie.tu-dresden.de [Department of Inorganic Chemistry, Dresden University of Technology, Bergstrasse 66, 01069 Dresden (Germany); Mohamed-Noriega, Nasser, E-mail: nasser.mohamed-noriega@chemie.tu-dresden.de [Department of Inorganic Chemistry, Dresden University of Technology, Bergstrasse 66, 01069 Dresden (Germany); Dörfler, Susanne, E-mail: susanne.doerfler@chemie.tu-dresden.de [Department of Inorganic Chemistry, Dresden University of Technology, Bergstrasse 66, 01069 Dresden (Germany); Hampel, Silke, E-mail: s.hampel@ifw-dresden.de [Leibniz Institute for Solid State and Materials Research (IFW) Dresden, Institute for Solid State Research, Helmholtzstr. 20, 01069 Dresden (Germany); Grothe, Julia, E-mail: stefan.kaskel@chemie.tu-dresden.de [Department of Inorganic Chemistry, Dresden University of Technology, Bergstrasse 66, 01069 Dresden (Germany); Kaskel, Stefan, E-mail: julia.grothe@chemie.tu-dresden.de [Department of Inorganic Chemistry, Dresden University of Technology, Bergstrasse 66, 01069 Dresden (Germany)

    2014-12-15

    Polydopamine, formed by oxidation of dopamine, is a bioinspired polymer developed for multifunctional coatings by Lee et al. in 2007 by drawing inspiration from the adhesive proteins found in mussels. Due to their high versatility and substrate-independence, polydopamine coatings are gaining considerable attention in a plethora of research fields, particularly in the coating of particles, but systematic investigations of the polydopamine coating process are lacking in the literature. In this study, we explore by TEM and thermogravimetric analysis the polydopamine coating process on alumina microparticles, tungsten carbide microparticles and tungsten carbide nanoparticles. By choosing two substrates with similar size but different material (Al{sub 2}O{sub 3} and WC), as well as two substrates of the same material but different size (WC micro- and nanoparticles) we investigate the effects of both substrate material and substrate size, in order to gain some insights into the polydopamine particle coating process. As opposed to what is generally assumed in the literature, we found that the polydopamine coating thicknesses on particles, as well as the thickness growing trend, depend on the particles size and material. In particular, after 24 h of polymerization time the polydopamine coatings reached a thickness of 65 ± 10 nm in the case of Al{sub 2}O{sub 3} microparticles, 18 ± 4 nm in the case of WC microparticles and 33 ± 6 nm in the case of WC nanoparticles. - Highlights: • The coating of different particles with polydopamine was systematically investigated. • Al{sub 2}O{sub 3} microparticles and WC microparticles and nanoparticles were investigated. • The thickness of the polydopamine coating depends on the particle size. • The thickness of the polydopamine coating depends on the particle material.

  19. Tolerancia al daño inducido bajo solicitaciones de contacto cíclicas en carburos cementados WC-Co//Tolerance induced damage under cyclic contact loading of WC-Co cemented carbides

    Directory of Open Access Journals (Sweden)

    David Coureaux‐Mustelier

    2014-01-01

    Full Text Available El comportamiento mecánico de los carburos cementados WC-Co ha sido estudiado en detalle teniendo en cuenta los defectos preexistentes del material (daño intrínseco. Sin embargo, la información sobre los efectos del daño inducido en servicio (daño extrínseco en la integridad estructural de estos materiales esescasa. En este contexto, en este trabajo se evalúa la influencia del daño extrínseco en la resistencia mecánica residual de dos calidades con microestructuras diferentes. Para ello, se emplea la técnica de indentación esférica como medio para generar daño de forma controlada. Los resultados muestran que al incrementar el tamaño de grano del carburo y el contenido de cobalto, la respuesta mecánica de carburos cementados frente al contacto esférico es cada vez más cuasi-plástica, bajo la aplicación de cargas tanto monotónicas como cíclicas, y en consecuencia el material muestra una mayor tolerancia al daño.Palabras claves: carburos cementados, indentación esférica, resistencia mecánica residual, tolerancia al daño._______________________________________________________________________________AbstractThe mechanical behavior of WC-Co cemented carbides has been studied in detail taking into account the pre-existing material (intrinsic damage defects. However, information on the effects of service-induced damage (extrinsic damage on the structural integrity of these materials is limited. In this context, in thispaper the influence of extrinsic damage on the residual strength of two grades with different microstructures is evaluated. With this purpose, a spherical indentation technique is employed as a means for generating a controlled damage. The results show that by increasing the grain size of the carbide and the cobalt content, the mechanical properties of cemented carbides compared to spherical contact isincreasingly quasi-plastic, under the application of both monotonic and cyclic loads, and consequently the

  20. Violence prevention in the ED: linkage of the ED to a social service agency.

    Science.gov (United States)

    Zun, Leslie S; Downey, La Vonne; Rosen, Jodi

    2003-10-01

    was a strong positive correlation of using services and case management (Pearson coefficient = 0.728, significance =.00). The referral of young victims of violence from the ED to psychosocial services could be successful using a case management model and an alliance between a healthcare system and a social service agency.

  1. Resistance of Cavitation Erosion of HVOF Sprayed WC-Co( Cr) Coating in NaCl Solution%超音速火焰喷涂WC-Co(Cr)涂层在NaCl溶液中抗空蚀性能研究

    Institute of Scientific and Technical Information of China (English)

    丁彰雄; 石琎; 丁翔; 胡一鸣; 廖星文; 邓帮华

    2016-01-01

    Two micro-structured WC-10Co4Cr cermet coatings and a nano-structured WC-12Co cermet coating are deposited by high velocity Oxy-fuel spray ( HVOF) , and the morphologies and structures of the coatings are analyzed by SEM .The coatings'porosity , fracture toughness and microhardness are measured .The CorrTest electrochemical testing system is used to analyze the electrochemical corrosion properties of the coatings .Resistance of coatings to cavitation erosion is studied by ultrasonic vibration cavitation equipment in 3.5wt%NaCl solution and the cavitation mechanisms are explored .It is shown that the nano-structured WC-12Co coating deposited by high velocity oxygen liquid fuel spray has lowest porosity and the densest microstructure , and frac-ture toughness is significantly higher than that of micron-structured WC-10Co4Cr coatings.Although the micron-structured WC-10Co4Cr cermet coating deposited by high velocity fuel oxygen liquid spray has coarser particles than the nano -structured, it ex-hibits the most excellent corrosion and cavitation erosion resistance .The cavitation rate is approximately one quarter that of the nano-structured WC-12Co cermet coating in 3.5wt%NaCl solution.%采用超音速火焰喷涂(HVOF)工艺制备2种微米结构WC-10Co4Cr及1种纳米结构WC-12Co金属陶瓷复合涂层;采用SEM分析涂层的组织结构;测量了涂层的显微硬度、孔隙率及开裂韧性;采用CorrT-est电化学测试系统分析涂层的电化学腐蚀性能;采用超声振动空蚀装置研究涂层在质量分数为3.5% NaCl溶液中的抗空蚀性能,探讨涂层的空蚀机理. 结果表明:使用液体燃料HVOF工艺喷涂的纳米WC-12Co涂层组织结构最细小,孔隙率最低,显微硬度和开裂韧性明显高于液体燃料和气体燃料HVOF工艺喷涂的微米WC-10Co4Cr涂层;采用液体燃料HVOF工艺喷涂的微米结构WC-10Co4Cr涂层在质量分数为3.5%NaCl溶液中显示了最优异的抗腐蚀和抗空蚀性能,空蚀率仅为纳米WC

  2. Thermally Induced Silane Dehydrocoupling on Silicon Nanostructures (International ed.)

    Science.gov (United States)

    2016-07-29

    Arkles Gelest Inc. 11 East Steel Rd., Morrisville, PA 19067 (USA) Y. W. Jun, Prof. Dr. K. H. Ahn Department of Chemistry Pohang University of Science...Figure 1a) and elemental analysis by energy-dispersive X-ray (EDS) analysis revealed strong carbon and oxygen signals (Table S2). By contrast, a

  3. Ed Henneke receives award for innovation in nondestructive testing research

    OpenAIRE

    Gilbert, Karen

    2005-01-01

    Ed Henneke, of Blacksburg, associate dean for research and graduate studies in the College of Engineering at Virginia Tech, received the Award for Innovation in Nondestructive Testing Research (NDT) at the American Society for Nondestructive Testing's 14th Annual Research Symposium in Albuquerque, N.M. This award was established to recognize highly distinguished individual breakthroughs in research in NDT.

  4. Murray Pittock, ed., The Edinburgh Companion to Scottish Romanticism.

    Directory of Open Access Journals (Sweden)

    Manfred Malzahn

    2013-10-01

    Full Text Available Murray Pittock, ed., The Edinburgh Companion to Scottish Romanticism. Edinburgh: Edinburgh University Press, 2011. Pp. 251. ISBN 978-0-7486-3845-1 (hardback. £ 65.00. ISBN 978-0-7486-3846-8 (paperback. £ 21.99.

  5. Review: Askew, Mark (ed.: Legitimacy Crisis in Thailand

    Directory of Open Access Journals (Sweden)

    Napisa Waitoolkiat

    2011-01-01

    Full Text Available Review of the edited volume: Askew, Mark (ed. (2010, Legitimacy Crisis in Thailand, Chiang Mai, Thailand: Silkworm Books (= King Prajadhipok’s Institute Yearbook No. 5 (2008/09. ISBN 978-974-9511-97-8, 340 pages

  6. Inside the Sex Ed Studio: An Interview with Peggy Brick

    Science.gov (United States)

    Taverner, William J.

    2008-01-01

    "Inside the Sex Ed Studio" profiles leaders in the field of sexuality education. Peggy Brick, former director of Planned Parenthood of Greater Northern New Jersey's Center for Family Life Education (CFLE) and author of numerous sexuality education resources used worldwide, is the subject of this interview. Ms. Brick was interviewed by…

  7. Creating a Minnesota Statewide SNAP-Ed Program Evaluation

    Science.gov (United States)

    Gold, Abby; Barno, Trina Adler; Sherman, Shelley; Lovett, Kathleen; Hurtado, G. Ali

    2013-01-01

    Systematic evaluation is an essential tool for understanding program effectiveness. This article describes the pilot test of a statewide evaluation tool for the Supplemental Nutrition Assistance Program-Education (SNAP-Ed). A computer algorithm helped Community Nutrition Educators (CNEs) build surveys specific to their varied educational settings…

  8. Engaging the public through writing an op-ed

    Science.gov (United States)

    Labosier, Chris; Zhu, Laiyin; Quiring, Steven

    2012-10-01

    In May, prior to the start of the 2012 hurricane season, AGU asked us to write an op-ed for the Houston Chronicle on the importance of funding hurricane research. We were excited to be asked and pleased that AGU facilitated the process by providing us with some guidance on writing the op-ed. Given the impact that Hurricane Ike had in Texas just a few years ago, we felt it was important to remind the citizens of the greater Houston metropolitan area of the societal benefits of funding hurricane research. Thanks to the assistance of AGU staff, writing the article required only a few hours of time. Our op-ed was published in the print edition of the Houston Chronicle on 1 June 2012, the official start of the hurricane season (http://www.chron.com/default/article/Tight-budgets-posing-threat-to-Texas-hurricane-3600363.php). It was picked up by the media relations office in the College of Geosciences at Texas A&M University and featured on the college's Web site in the dean's biweekly briefing and on its Facebook page. As a result, the op-ed reached a large and diverse audience.

  9. Candidate Success and edTPA: Looking at the Data

    Science.gov (United States)

    Evans, Lesley A.; Kelly, Mary K.; Baldwin, Joni L.; Arnold, Jackie M.

    2016-01-01

    This descriptive study looks at the correlations between Teacher Performance Assessment (edTPA) data and numerous program data points, including GPA, major GPA, and benchmark assignment scores, gathered in an Early Childhood Education (ECE) program. Previous studies have looked to correlate grade point average (GPA) with pre-service teacher…

  10. Lifeworld and Textualism: Reassembling the Researcher/ed and "Others"

    Science.gov (United States)

    Payne, Phillip G.

    2005-01-01

    This response to McKenzie's "post-post" concerns about environmental education research draws upon empirical, conceptual, anecdotal, metaphorical, imaged and poetic means to help the researcher "reassemble" the researcher/ed by attending to her/his relational body and embodiment of various, often hegemonic, socially constructed environmental…

  11. TRAUMA (RE-)IMAG(IN)ED: EXPERIENCES AND MEMORIES OF ...

    African Journals Online (AJOL)

    imitch

    terms what trauma is, and interfaces it with how Soyinka has (re-)imag(in)ed it and submits ... innermost and visceral thoughts and being of his characters. .... Like The Man Died, Madmen and Specialists arose from Soyinka's painful and traumatic acquaintance ... out of the period, which I stayed in prison, which was just over.

  12. Comportamiento a desgaste de recubrimientos de WC proyectados por plasma a partir de polvos micro y nanoestructurados

    Directory of Open Access Journals (Sweden)

    Salvador, M. D.

    2008-06-01

    Full Text Available The aim of the present work is the study of wear behaviour of different WC coatings deposited on stainless steel substrate by means of atmospheric plasma spraying (APS. Two types of WC commercial powders, with different metal binder (12% Cobalt and 10% Nickel have been deposited in order to analyse the influence of the metal matrix and thickness of the coating in tribological properties.The microstructure of the depositions was characterized using scanning electron microscopy (SEM and X-ray diffraction analysis (XRD. On the other hand, tribology characterization of the coatings was made by pin-on-disk wear tests against alumina (2400HV and silicon nitride (1600HV ceramic balls, without lubrication. Wear rates and friction coefficient evolution have been calculated. Finally, wear tracks and wear debris have been analysed with the help of SEM.The results of each pair of tested materials show different mechanisms of wear related to the nature of the ball that has been used, obtaining higher wear rates with silicone nitride ball..In a second phase of the study, in order to examine the influence of the initial particle size on the wear properties of the coatings, cobalt based coatings have been analysed with different initial particle size (micrometric and nanometric particles.Results show that nanostructured coatings have higher wear resistance than microstrutured ones for high loads. However for low loads, behaviour is similar in spite of the microstructural differences appreciated.

    El objetivo de este trabajo es estudiar el comportamiento a desgaste de distintos recubrimientos de WC sobre acero inoxidable mediante proyección por plasma atmosférico. Se proyectan dos tipos de polvos comerciales con base cobalto (12 % y níquel (10 %, con el objeto de analizar la influencia de la matriz e incluso del espesor del recubrimiento. Los recubrimientos obtenidos se caracterizan microestructuralmente por microscopía electrónica de barrido y

  13. TrED: the Trichophyton rubrum Expression Database

    Directory of Open Access Journals (Sweden)

    Liu Tao

    2007-07-01

    Full Text Available Abstract Background Trichophyton rubrum is the most common dermatophyte species and the most frequent cause of fungal skin infections in humans worldwide. It's a major concern because feet and nail infections caused by this organism is extremely difficult to cure. A large set of expression data including expressed sequence tags (ESTs and transcriptional profiles of this important fungal pathogen are now available. Careful analysis of these data can give valuable information about potential virulence factors, antigens and novel metabolic pathways. We intend to create an integrated database TrED to facilitate the study of dermatophytes, and enhance the development of effective diagnostic and treatment strategies. Description All publicly available ESTs and expression profiles of T. rubrum during conidial germination in time-course experiments and challenged with antifungal agents are deposited in the database. In addition, comparative genomics hybridization results of 22 dermatophytic fungi strains from three genera, Trichophyton, Microsporum and Epidermophyton, are also included. ESTs are clustered and assembled to elongate the sequence length and abate redundancy. TrED provides functional analysis based on GenBank, Pfam, and KOG databases, along with KEGG pathway and GO vocabulary. It is integrated with a suite of custom web-based tools that facilitate querying and retrieving various EST properties, visualization and comparison of transcriptional profiles, and sequence-similarity searching by BLAST. Conclusion TrED is built upon a relational database, with a web interface offering analytic functions, to provide integrated access to various expression data of T. rubrum and comparative results of dermatophytes. It is devoted to be a comprehensive resource and platform to assist functional genomic studies in dermatophytes. TrED is available from URL: http://www.mgc.ac.cn/TrED/.

  14. Microstructure and properties of WC-4 Co coating on surface of cast steel prepared by electrospark deposition%铸钢材料电火花表面沉积WC-4Co涂层的组织与性能

    Institute of Scientific and Technical Information of China (English)

    王建升; 高玉新; 张瑞珠

    2010-01-01

    采用电火花沉积工艺,在铸钢表面制备了WC-4Co沉积涂层,采用X射线衍射仪、扫描电镜、显微硬度计等对沉积层的相结构、显微组织、显微硬度及耐磨性能进行了分析.结果表明:沉积层主要由Co3W3C、Fe3W3C、W2C、Fe7W6等相组成;沉积层与基体呈冶金结合,Fe7W6、W2C等硬质相弥散分布于沉积层中,部分区域硬质相达到了纳米颗粒尺寸;沉积层的平均硬度为1517HV0.3,约是基体硬度(502 HV0.3)的3倍;其耐磨性能比基体提高了2.4倍;沉积层的主要磨损机制为疲劳磨损,细小的弥散分布的硬质相是沉积层硬度以及耐磨性能提高的主要因素.

  15. WC基涂层材料和制备工艺对其组织结构与性能的影响%Effect of WC Based Coating Materials and Fabrication Technology on the Structures and Properties

    Institute of Scientific and Technical Information of China (English)

    石琎; 丁翔; 胡一鸣; 丁彰雄; 肖俊钧; 王韶毅

    2015-01-01

    本文采用超音速火焰(HVOF)喷涂工艺制备了二种微米结构WC-10Co-4Cr及一种纳米结构WC-12Co金属陶瓷复合涂层;采用SEM、XRD等分析了涂层的组织结构;测量了涂层的显微硬度、孔隙率及开裂韧性;采用超声振动空蚀装置研究了涂层的抗空蚀性能,探讨了涂层空蚀机理。结果表明:由燃油型HVOF工艺制备的纳米WC-12Co涂层孔隙率最低,组织最细小,开裂韧性明显高于燃油型和燃气型HVOF工艺制备的微米WC-10Co-4Cr涂层;燃油型HVOF工艺制备的微米结构WC-10Co-4Cr涂层显示了最优异的抗空蚀性能,空蚀率仅为纳米WC-12Co涂层的1/3左右。%Two micro-structured WC-10Co-4Cr cermet coatings and a nano-structured WC-12Co cermet coating were deposited by High Velocity Oxy-Fuel spray(HVOF),and the morphologies and structures of the coatings were analyzed by SEM and XRD. Porosity, microhardness and fracture toughness of the coatings were measured. Resistance of coatings to cavitation erosion was studied by ultrasonic vibration cavitation equipment and the cavitation mechanisms were explored. Results show that the nano-structured WC-12Co coating deposited by High Velocity Fuel spray had lowest porosity and the densest microstructure and fracture toughness was significantly higher than that of micron-structured WC-10Co-4Cr coatings. Although the micron-structured WC-10Co-4Cr cermet coating deposited by HVOF had more coarser particles than the nano-structured, it exhibited the most excellent resistance to cavitation erosion, and the cavitation erosion rate was approximately one third that of the nano-structured WC-12Co cermet coating.

  16. Comprehensive modelling of the planetary nebula LMC-SMP 61 and its [WC]-type central star

    CERN Document Server

    Stasinska, G; Peña, M; Hamann, W R; Koesterke, L; Szczerba, R

    2003-01-01

    We present a comprehensive study of the Magellanic Cloud planetary nebula SMP 61 and of its nucleus, a Wolf-Rayet type star classified [WC 5-6]. We have performed a detailed spectral analysis of the central star, using the Potsdam code for expanding atmospheres in non-LTE. The fluxes from the model stellar atmosphere were used to compute photoionization models of the nebula. All the available observations, within their error bars, were used to constrain these models. We find that the ionizing fluxes predicted by the stellar model are basically consistent with the fluxes needed by the photoionization model to reproduce the nebular emission, within the error margins. However, there are indications that the stellar model overestimates the number and hardness of Lyman continuum photons. The photoionization models imply a clumped density structure of the nebular material. The observed CIII] 1909/CII 4267 line ratio implies the existence of carbon-rich clumps in the nebula. Such clumps are likely produced by stella...

  17. Effect of cobalt content on wear and corrosion behaviors of electrodeposited Ni-Co/WC nano-composite coatings.

    Science.gov (United States)

    Amadeh, A; Ebadpour, R

    2013-02-01

    Metal-ceramic composite coatings are widely used in automotive and aerospace industries as well as micro-electronic systems. Electrodeposition is an economic method for application of these coatings. In this research, nickel-cobalt coatings reinforced by nano WC particles were applied on carbon steel substrate by pulse electrodeposition from modified Watts bath containing different amounts of cobalt sulphate as an additive. Saccharin and sodium dodecyl sulphate (SDS) were also added to electroplating bath as grain refiner and surfactant, respectively. The effect of cobalt content on wear and corrosion behavior of the coatings was investigated. Wear and corrosion properties were assessed by pin-on-disk and potentiodynamic polarization methods, respectively. Phase analysis was performed by X-ray diffraction (XRD) using CuK(alpha) radiation and the worn surfaces were studied by means of Scanning Electron Microscopy (SEM). The results showed that the addition of cobalt improved the wear resistance of the coatings. In the presence of 18 g/L cobalt in electrodeposition bath, the wear rate of the coating decreased to 0.002 mg/m and the coefficient of friction reduced to 0.695 while they were 0.004 mg/m and 0.77 in the absence of cobalt, respectively. This improvement in wear properties can be attributed to the formation of hcp phase in metallic matrix. Meanwhile, the corrosion resistance of the coatings slightly reduced because cobalt is more active metal with respect to nickel.

  18. The Abrasion Resistance and Adhesion of Hfcvd Boron and Silicon-Doped Diamond Films on WC-Co Drawing Dies

    Science.gov (United States)

    Wang, Liang; Liu, Jinfei; Tang, Tang; Sun, Fanghong; Xie, Nan

    Diamond films have been deposited on the interior hole surface of cobalt-cemented tungsten carbide (WC-Co) drawing dies from acetone, trimethyl borate (C3H9BO3), tetraethoxysilane (C8H20O4Si, TEOS) and hydrogen mixture by hot-filament chemical vapor deposition (HFCVD) method. The structures and quality of as-deposited diamond films are characterized with field-emission scanning electron microscopy (FESEM) and Raman spectroscopy. The abrasion ratio and the adhesive strength of as-deposited diamond films are evaluated by copper wire drawing tests and ultrasonic lapping tests, respectively. The results suggest that diamond films with small grain size and high growth rate can be obtained due to the mutual effects of boron and silicon impurities in the gas phases. The results of ultrasonic lapping tests show that diamond films doped with boron and/or silicon can bear the severe erosion of the large diamond powder. Diamond films peeling off within the reduction zone of the drawing dies cannot be observed after testing of 2h. The abrasion ratio of boron and silicon-added diamond films is five times that of diamond films without any addition. Adding boron and/or silicon in the diamond films is proved to be an efficient way to obtain high-adhesive-strength and high-abrasion-resistance diamond-coated drawing dies.

  19. Influence of Processing Parameters on Residual Stress of High Velocity Oxy-Fuel Thermally Sprayed WC-Co-Cr Coating

    Science.gov (United States)

    Gui, M.; Eybel, R.; Asselin, B.; Radhakrishnan, S.; Cerps, J.

    2012-10-01

    Residual stress in high velocity oxy-fuel (HVOF) thermally sprayed WC-10Co-4Cr coating was studied based on design of experiment (DOE) with five factors of oxygen flow, fuel gas hydrogen flow, powder feed rate, stand-off distance, and surface speed of substrate. In each DOE run, the velocity and temperature of in-flight particle in flame, and substrate temperature were measured. Almen-type N strips were coated, and their deflections after coating were used for evaluation of residual stress level in the coating. The residual stress in the coating obtained in all DOE runs is compressive. In the present case of HVOF thermally sprayed coating, the residual stress is determined by three types of stress: peening, quenching, and cooling stress generated during spraying or post spraying. The contribution of each type stress to the final compressive residual stress in the coating depends on material properties of coating and substrate, velocity and temperature of in-flight particle, and substrate temperature. It is found that stand-off distance is the most important factor to affect the final residual stress in the coating, following by two-factor interaction of oxygen flow and hydrogen flow. At low level of stand-off distance, higher velocity of in-flight particle in flame and higher substrate temperature post spraying generate more peening stress and cooling stress, resulting in higher compressive residual stress in the coating.

  20. Evaluation of the Shearing Strength of a WC-12Co Thermal Spray Coating by the Scraping Test Method

    Directory of Open Access Journals (Sweden)

    Kenji Kaneko

    2015-07-01

    Full Text Available This paper reports on an experimental and analytical investigation conducted into efficacy of the scraping shear-test method in estimating the shearing adhesive strength of a thermally sprayed coating. It was found that the critical average shear stress, the apparent failure strength of WC-Co thermal spray coating, depends on both the dimensions of the test piece and the loading position around the interface between the coating and the substrate. More specifically, the apparent critical shear stress decreased as the height and width of the test piece increased. In addition, the apparent critical shear stress increased with increasing coating thickness and with decreasing loading point distance measured from the interface. Consequently, the real adhesive strength of thermally sprayed coating could not be ascertained from these experimental results. Furthermore, most of the failure initiation points were inside the coating, as opposed to at the interface. This fact means that the results of the tests do not indicate the interfacial adhesive strength, but rather the shear strength of the coating. Three-dimensional finite element method (FEM analysis showed that the distributions of the shearing stress at the loading points were virtually the same at failure, regardless of the dimensions of the test piece. These results suggest that the scraping test method needs a corresponding numerical analysis of the failure mode in order to produce reliable results and is not necessarily able to estimate the interfacial adhesive strength of thermally sprayed coating.

  1. Formation Mechanisms, Structure, and Properties of HVOF-Sprayed WC-CoCr Coatings: An Approach Toward Process Maps

    Science.gov (United States)

    Varis, T.; Suhonen, T.; Ghabchi, A.; Valarezo, A.; Sampath, S.; Liu, X.; Hannula, S.-P.

    2014-08-01

    Our study focuses on understanding the damage tolerance and performance reliability of WC-CoCr coatings. In this paper, the formation of HVOF-sprayed tungsten carbide-based cermet coatings is studied through an integrated strategy: First-order process maps are created by using online-diagnostics to assess particle states in relation to process conditions. Coating properties such as hardness, wear resistance, elastic modulus, residual stress, and fracture toughness are discussed with a goal to establish a linkage between properties and particle characteristics via second-order process maps. A strong influence of particle state on the mechanical properties, wear resistance, and residual stress stage of the coating was observed. Within the used processing window (particle temperature ranged from 1687 to 1831 °C and particle velocity from 577 to 621 m/s), the coating hardness varied from 1021 to 1507 HV and modulus from 257 to 322 GPa. The variation in coating mechanical state is suggested to relate to the microstructural changes arising from carbide dissolution, which affects the properties of the matrix and, on the other hand, cohesive properties of the lamella. The complete tracking of the coating particle state and its linking to mechanical properties and residual stresses enables coating design with desired properties.

  2. Study on dry friction and wear resistance of a WC-Co particle reinforced iron matrix composite material

    Directory of Open Access Journals (Sweden)

    Zhang Peng

    2013-05-01

    Full Text Available In order to select a suitable material for the rolling mill guide application, the dry sliding friction and wear resistance of a tungsten carbide combining cobalt (WC-Co particle reinforced chromium cast iron composite material were studied. In particular, the wear resistance was discussed in detail. The results showed that the composite material demonstrates 25 times the wear resistance of high Cr cast iron, and 9 times the wear resistance of heat resistant steel. However, the average friction factor in the stable friction stage showed a relationship of μComposites/45 # steel > μHigh chromium cast iron/45 # steel > μHeat resistant steel/45 # steel. The wear resistance mechanism of the composite material was associated with the reinforcing particles, which protruded from the worn surface to bear the friction load when the matrix material surface was worn, thereby reducing the abrasive and adhesive wear. In addition, the matrix material possessed suitable hardness and toughness, providing a support to the reinforcements.

  3. Effects of Trophic Modes, Carbon Sources, and Salinity on the Cell Growth and Lipid Accumulation of Tropic Ocean Oilgae Strain Desmodesmus sp. WC08.

    Science.gov (United States)

    Zhao, Zhenyu; Ma, Shasha; Li, Ang; Liu, Pinghuai; Wang, Meng

    2016-10-01

    The effects of trophic modes, carbon sources, and salinity on the growth and lipid accumulation of a marine oilgae Desmodesmus sp. WC08 in different trophic cultures were assayed by single factor experiment based on the blue-green algae medium (BG-11). The results implied that biomass and lipid accumulation culture process were optimized depending on the tophic modes, sorts, and concentration of carbon sources and salinity in the cultivation. There was no significant difference in growth or lipid accumulation with Na2CO3 amendment or NaHCO3 amendment. However, Na2CO3 amendment did enhance the biomass and lipid accumulation to some extent. The highest Desmodesmus sp. WC08 biomass and lipid accumulation was achieved in the growth medium with photoautotrophic cultivation, 0.08 g L(-1) Na2CO3 amendment and 15 g L(-1) sea salt, respectively.

  4. Parameter determination for the Cross rheology equation and its application to modeling non-Newtonian flows using the WC-MPS method

    Directory of Open Access Journals (Sweden)

    Jun Xie

    2016-01-01

    Full Text Available A weakly compressible moving particle semi-implicit (WC-MPS method is utilized to simulate non-Newtonian free surface flows due to the advantages of particle methods with respect to handling large deformation and fragmentation. The Cross rheology equation was selected in order to capture the viscous features of the mixture flows. To numerically implement the Cross equation, an experiment-based method was proposed to determine the four rheology parameters in the equation. The method of using a WC-MPS model to study non-Newtonian dam break flow problems was then adopted. The capabilities of the proposed method were tested by simulating different materials with the proposed method in modeling non-Newtonian free surface flows. Significant viscous features were reproduced by the proposed model.

  5. Nanoscale voxel spectroscopy by simultaneous EELS and EDS tomography.

    Science.gov (United States)

    Haberfehlner, Georg; Orthacker, Angelina; Albu, Mihaela; Li, Jiehua; Kothleitner, Gerald

    2014-11-01

    Extending the capabilities of electron tomography with advanced imaging techniques and novel data processing methods, can augment the information content in three-dimensional (3D) reconstructions from projections taken in the transmission electron microscope (TEM). In this work we present the application of simultaneous electron energy-loss spectroscopy (EELS) and energy-dispersive X-ray spectroscopy (EDS) to scanning TEM tomography. Various tools, including refined tilt alignment procedures, multivariate statistical analysis and total-variation minimization enable the 3D reconstruction of analytical tomograms, providing 3D analytical metrics of materials science samples at the nanometer scale. This includes volumetric elemental maps, and reconstructions of EDS, low-loss and core-loss EELS spectra as four-dimensional spectrum volumes containing 3D local voxel spectra. From these spectra, compositional, 3D localized elemental analysis becomes possible opening the pathway to 3D nanoscale elemental quantification.

  6. Processing and characterization of an Al{sub 2}O{sub 3}/WC/TiC micro- nano-composite ceramic tool material

    Energy Technology Data Exchange (ETDEWEB)

    Zhao Jun, E-mail: zhaojun@sdu.edu.cn [Key Laboratory of High Efficiency and Clean Mechanical Manufacture of MOE, School of Mechanical Engineering, Shandong University, 17923 Jingshi Road, Jinan 250061 (China); Yuan Xunliang [Seco Tools (Shanghai) Co. Ltd., Shanghai 200233 (China); Zhou Yonghui [Key Laboratory of High Efficiency and Clean Mechanical Manufacture of MOE, School of Mechanical Engineering, Shandong University, 17923 Jingshi Road, Jinan 250061 (China)

    2010-03-25

    An Al{sub 2}O{sub 3}-based composite ceramic tool material reinforced with WC microparticles and TiC nano-particles was fabricated by using hot-pressing technique with MgO and NiO as sintering aids. The experimental results showed that optimal mechanical properties were achieved for the composite with the addition of 24 vol.% TiC nano-particles and 16 vol.% WC microparticles, with the flexural strength, fracture toughness and Vicker's hardness being 842 MPa, 6.82 MPa m{sup 1/2} and 22.19 GPa, respectively. The microstructure and phase composition of the composites were characterized with scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray diffraction (XRD). The fracture surface of the Al{sub 2}O{sub 3}/16 vol.%WC/24 vol.%TiC micro- nano-composite was characterized by a mix of intergranular and transgranular fracture as a result of the presence of both intergranular and intragranular secondary phase particles. It is believed that inhibition of matrix grain growth by intergranular secondary phase particles, sub-grain boundaries and dislocations pinning inside Al{sub 2}O{sub 3} grains induced by intragranular TiC nano-particles contribute to the strengthening of the composite. Meanwhile, the dislocations and microcracks inside the matrix grains can also increase the flaw-tolerance leading to high toughness of the composite. Additionally, some extrinsic processes including crack deflection, crack bridging and crack branching caused by the microstructural discontinuities and local stress state can absorb a great amount of fracture energy, which are beneficial for the toughening of the composite. However, future research will need to quantitatively understand the synergistic effect of TiC nano-particles and WC microparticles on strengthening and toughening mechanisms.

  7. Modelizacion de la formación de recubrimientos de WC-Co por proyección HVOF sobre sustratos de cobre

    OpenAIRE

    Sobolev, V. V.; Guilemany, J. M.; J.A. Calero

    1997-01-01

    Present paper deals with the mathematical simulation of the heat transfer between a WC-Co coating and a copper substrate during HVOF spraying. This modelling includes the investigation of temperature variation, coating solidification, melting and subsequent solidification in the substrate interfacial region and specific features of the substrate-coating thermal interaction. The results obtained are used for modelling of the development of the coating structure and adhesion during HVOF sprayin...

  8. Differential cDNA cloning by enzymatic degrading subtraction (EDS).

    OpenAIRE

    1994-01-01

    We describe a new method, called enzymatic degrading subtraction (EDS), for the construction of subtractive libraries from PCR amplified cDNA. The novel features of this method are that i) the tester DNA is blocked by thionucleotide incorporation; ii) the rate of hybridization is accelerated by phenol-emulsion reassociation; and iii) the driver cDNA and hybrid molecules are enzymatically removed by digestion with exonucleases III and VII rather than by physical partitioning. We demonstrate th...

  9. States leverage telepsychiatry solutions to ease ED crowding, accelerate care.

    Science.gov (United States)

    2015-02-01

    Many states are having success turning to telepsychiatry-based solutions to connect mental health patients with needed care while also decompressing crowded EDs. Just one year into a statewide telepsychiatry initiative in North Carolina (NC-STeP), administrators say the approach has saved as much as $7 million, and hospital demand for the service is higher than anticipated. In Texas, mental health emergency centers (MHEC) that use telepsychiatry to connect patients in rural areas with needed psychiatric care are freeing up EDs to focus on medical care. In just 11 months, 91 North Carolina hospitals have at least started the process to engage in NC-STeP. Much of the savings from NC-STeP come from involuntary commitment orders being overturned as a result of the telepsychiatry consults, reducing the need for expensive inpatient care. Implementing NC-STeP has involved multiple hurdles including credentialing difficulties and technical/firewall challenges. The Texas model provides 24/7 availability of psychiatrists via telemedicine through a network of MHECs. In-person staff at the MHECs perform basic screening tests and blood draws so that medical clearance can be achieved without the need for an ED visit in most cases. Funding for the MHECs comes from the state, hospitals in the region, and local governmental authorities that reap savings or benefits from the initiative.

  10. Tribological Properties of WC-Co/NiCrBSi and Mo/NiCrBSi Plasma Spray Coatings under Boundary Lubrication Conditions

    Directory of Open Access Journals (Sweden)

    A. Vencl

    2017-06-01

    Full Text Available The tungsten carbide based WC-Co/NiCrBSi (50/50 and molybdenum based Mo/NiCrBSi (75/25 coatings were investigated under boundary lubricated sliding conditions, and their tribological properties were analysed and compared. These two coatings are in service for a long time, but there are very few papers dealing with their tribological properties, especially in lubricated sliding conditions. The NiCrBSi self-fluxing alloy is one of the popularly used materials for thermal sprayed coating, with relatively high hardness, reasonable wear resistance and high temperature corrosion. Tungsten carbide (WC is one of the most widely used commercial hard coating materials, and is added to the NiCrBSi coating to improve its hardness and wear resistance. Molybdenum (Mo is added to the NiCrBSi coating to reduce its coefficient of friction, i.e. to improve its dry sliding wear resistance. The results showed that WC-Co/NiCrBSi coating was more wear resistant, but caused higher wear of the counter-body material. Coefficients of friction were similar for both coatings.

  11. BMI, WC, WHtR, VFI and BFI:Which Indictor is the Most Efficient Screening Index on Type 2 Diabetes in Chinese Community Population

    Institute of Scientific and Technical Information of China (English)

    MI Sheng Quan; YIN Peng; HU Nan; LI Jian Hong; CHEN Xiao Rong; CHEN Bo; YAN Liu Xia; ZHAO Wen Hua

    2013-01-01

    Objective Obesity is a major risk factor for type 2 diabetes, many indexes can be used to describes obesity and predict diabetes. This research attempts to identify the best indicator of obesity to screening diabetes in Chinese population. Methods A cross-sectional data of 8121 subjects aged 35-60 years were included in this research belongs to the Diabetes Appropriate Technology Intervention Study. Anthropometric indicators including body weight, height, waist circumferences (WC), body fat index (BFI) and visceral fat index (VFI) and blood biochemical indicators after an overnight fast [fasting blood glucose, total cholesterol, high-density lipoprotein (HDL) cholesterol, and triacylglycerol] were measured. BMI (body mass index) and Weight to Height Ratio was calculated. Results Subjects with obesity had a higher risk of physician diagnosed diabetes (OR=2.50, 95% CI 1.83-3.43), new diagnosed diabetes (OR=4.23, 95% CI 2.91-6.15) and pre-diabetes (OR=1.75, 95% CI 1.31-2.34) compared to those with normal Body mass index (BMI). There was a significant trend of increased risk of all diabetes status with increased waist circumference (WC). The waist-to-height ratio (WHtR) yielded the most significant association with new diagnosed diabetes and physician diagnosed diabetes than other indices. Conclusion Central obesity is significantly correlated with diabetes. VFI was most correlated with pre-diabetes while WHtR is an efficient screening index than BMI and WC in Chinese community diabetes screening.

  12. Microstructural Modification of Laser-Deposited High-Entropy CrFeCoNiMoWC Alloy by Friction Stir Processing: Nanograin Formation and Deformation Mechanism

    Science.gov (United States)

    Li, Ruidi; Wang, Minbo; Yuan, Tiechui; Song, Bo; Shi, Yusheng

    2017-02-01

    Nanostructured CrFeCoNiMoWC high-entropy alloy layer was developed through laser-melting deposition and severe plastic deformation (SPD). The laser-deposited CrFeCoNiMoWC alloy consists of dendritic and subeutectic with a continuous network structure. After SPD, the laser-deposited microstructure with grain size 3 to 4 μm was transformed into nanostructure with grain size 5 to 100 nm and the continuous networks were crushed into dispersed nanoparticles. The new phases of WC and Co3W were presented in the plastic zone after SPD due to the worn debris of the SPD tool. More interestingly, amorphous phase was found in the plastic zone, owing to the high temperature, high hydrostatic pressure, and large shear stress. The refined microstructure resulted in the enhancement of microhardness and electrochemical corrosion property. Many nanotwins were detected in the plastic zone; thus, strengthening mechanisms were reasonably inferred as twinning strengthening, work hardening, dispersion strengthening, refinement strengthening, and dislocation strengthening. The Lomer-Cottrell lock, full dislocation interacting with a partial dislocation at the twinning boundary, and high density of dislocation at the twinning boundary, stacking fault, and grain boundary were observed, which account for the property enhancement of the nanocrystalline.

  13. Surface Layer States of Worn Uncoated and TiN-Coated WC/Co-Cemented Carbide Cutting Tools after Dry Plain Turning of Carbon Steel

    Directory of Open Access Journals (Sweden)

    Johannes Kümmel

    2013-01-01

    Full Text Available Analyzing wear mechanisms and developments of surface layers in WC/Co-cemented carbide cutting inserts is of great importance for metal-cutting manufacturing. By knowing relevant processes within the surface layers of cutting tools during machining the choice of machining parameters can be influenced to get less wear and high tool life of the cutting tool. Tool wear obviously influences tool life and surface integrity of the workpiece (residual stresses, surface quality, work hardening, etc., so the choice of optimised process parameters is of great relevance. Vapour-deposited coatings on WC/Co-cemented carbide cutting inserts are known to improve machining performance and tool life, but the mechanisms behind these improvements are not fully understood. The interaction between commercial TiN-coated and uncoated WC/Co-cemented carbide cutting inserts and a normalised SAE 1045 steel workpiece was investigated during a dry plain turning operation with constant material removal under varied machining parameters. Tool wear was assessed by light-optical microscopy, scanning electron microscopy (SEM, and EDX analysis. The state of surface layer was investigated by metallographic sectioning. Microstructural changes and material transfer due to tribological processes in the cutting zone were examined by SEM and EDX analyses.

  14. 电火花沉积WC-4Co复合层界面行为%Interface behavior of WC-4Co coating by electro-spark deposition

    Institute of Scientific and Technical Information of China (English)

    王建升; 张占哲; 闫镇威; 李刚; 唐明奇; 冯在强

    2014-01-01

    Submicron WC-4Co cemented carbide material was deposited on the surface of cast steel by electro-spark deposition (ESD), the electro-spark deposition coating was prepared. The behavior of interface between the coating and the substrate was studied by SEM and XRD. The surface wettability, the forming mechanism of phase, microstructure, element distribution of deposition, bonding mechanism of interface and microhardness of the coating were investigated. The results show that micro/nano and amorphous coating with high melting-point is produced on the surface of cast steel by ESD. The coating consists of Fe 3 W 3 C, Co 3 W 3 C,Si 2 W and Fe 2 C phases. The coating is well metallurgical bonded with the cast steel roll substrate. The microstructure of the transition layer is a structure of fine columnar crystals and equiaxed crystals. The extra-fine structure hard Si2W and Fe2C phases distribute dispersedly in Fe3W3C and Co3W3C deposition. The coating is usually more than 20 µm thick. The average microhardness of the coating is 1803. 2 HV. These fine and dispersed hard phases can greatly improve the hardness of coating.%采用新型电火花沉积设备,将亚微米WC-4Co陶瓷硬质合金材料沉积在铸钢材料上,制备电火花沉积合金涂层,利用SEM和XRD等技术研究沉积层与基体间的界面行为,分析沉积层的表面润湿性、物相形成机理、微观组织结构、界面元素分布、界面结合机理和显微硬度变化等。结果表明:电火花沉积技术可以在金属基体表面制造出微纳米非晶高熔点强化层。铸钢表面沉积层主要由Fe3W3C、Co3W3C、Si2W和Fe2C 等相组成;沉积层与基体呈冶金结合,过渡层中出现一些柱状晶和等轴晶的组织结构,沉积层中细小的Fe2C和Si2W等硬质相颗粒弥散分布于Fe 3 W 3 C和Co 3 W 3 C沉积层上。沉积层的厚度大于20µm,沉积层的平均显微硬度为1803.2 HV,细小弥散分布的硬质相是沉积层硬度提高的主要因素。

  15. Preparation of WC@TiO2 Core-shell Nanocomposite and Its Electrocatalytic Characteristics%WC@TiO2核壳结构纳米复合材料制备与电催特征

    Institute of Scientific and Technical Information of China (English)

    李国华; 陈丹; 姚国新; 施斌斌; 马淳安

    2011-01-01

    Monotungsten carbide and titania nanocomposite with core-shell (WC@TiO2) structure was prepared by a new approach of spray drying and reduction-carbonization reaction, with titania nanopowder and ammonium metatungstate as precursors, methane as carbon source, and hydrogen as reduction gas. The sample was characterized by X-ray diffraction, scanning electron microscope, high resolution transmission electron microscope and X-ray energy dispersion spectroscopy. The results show that its crystal phase is composed of brookite, tungsten and monotungsten carbide. The morphology of the sample particle is irregular sphere-like, with a diameter smaller than 100 nm. Its chemical components are titanium, tungsten, carbon and oxygen. Monotungsten carbide nanoparticles lie on the surface of titania core and form an incomplete shell around titania core in the nanocomposite. The measurement with a microelectrode system of three electrodes shows that the sample is electrocatalytic active to nitrophenol in basic solution at room temperature. Its peak potential is at -0.988 V (vs saturated calomel electrode (SCE)), which is more negative than the peak potential, -0.817 V (vs SCE), of mesoporous monotungsten carbide,and its peak current is 8.809 μA, which is higher than the peak current, 4.058 μA, of mesoporous monotungsten carbide. The hydrogen generation potential of the sample is at -1.199 V (vs SCE), which is more negative than that of pure nanosized monotungsten carbide at -1.100 V (vs SCE). These results show that the presence of titania in the sample can lower the peak potential of nitrophenol electrocatalysis and its hydrogen generation potential, and increase its peak current of nitrophenol electrocatalysis in basic solution at room temperature. This indicates a synergistic effect of titania and monotungsten carbide in electrocatalysis.

  16. Standardisation of the Waist Circumference (WC for each range of Body Mass Index (BMI in adult outpatients attended to in Endocrinology and Nutrition Departments Estandarización de la circunferencia de cintura (WC, para cada rango de índice de masa corporal (BMI en pacientes adultos atendidos en un servicio de endocrinología y nutrición

    Directory of Open Access Journals (Sweden)

    M. López de la Torre

    2010-04-01

    Full Text Available By this study we seek the expectable range of waist circumference (WC for every degree of body mass index (BMI, which will serve to studies targeting ascertaining the health risk. We studied 2,932 patients (39.6% men and 60.4% women, between 18 and 96 years of the same ethnic group who consecutively attended outpatient departments of our clinics between 2000 and 2004.. BMI correlated linearly with the WC (cc: 0.85; p = 102 cm and women > = 88 cm in 94.3% of the obese, in 32.3% of overweight patients, in 3.8% of patients with BMI En este estudio hemos buscado el rango de circunferencia de cintura (WC para cada grado de índice de masa corporal (BMI, que sirva para estudios que determinen riesgos de salud. Estudiamos 2.932 pacientes (39,6% varones y 60,4% mujeres, entre 18 y 96 años del mismo grupo étnico que consecutivamente asistieron a consultas externas de nuestras clínicas entre 2000 and 2004. El BMI correlacionó linealmente con la WC (cc: 0,85; p = 102 cm y mujeres > = 88 cm la presentaban el 94,3% de los obesos, el 32,3% de los pacientes con sobrepeso y el 3,8% de pacientes con BMI < 25, el 84,3% de diabéticos y el 72,6% de pacientes sin diabetes. Elaboramos una estandarización gráfica de WC en relación con BMI y calculamos los precentiles 10, 25, 50, 75 y 90, agrupados en rangos de 2 kg/m² de BMI. Como el número de diabeticos es menor, los agrupamos en rangos de 4 kg/m². En conclusión presentamos una estandarización de la WC de pacientes atendidos en nuestra consulta de endocrinología y nutrición distribuidos en percentiles como herramienta utilizable clínicamente para definir rangos de WC para cada valor de BMI.

  17. Impact of prospective verification of intravenous antibiotics in an ED.

    Science.gov (United States)

    Hunt, Allyson; Nakajima, Steven; Hall Zimmerman, Lisa; Patel, Manav

    2016-12-01

    Delay in appropriate antibiotic therapy is associated with an increase in mortality and prolonged length of stay. Automatic dispensing machines decrease the delivery time of intravenous (IV) antibiotics to patients in the emergency department (ED). However, when IV antibiotics are not reviewed by pharmacists before being administered, patients are at risk for receiving inappropriate antibiotic therapy. The objective of this study was to determine if a difference exists in the time to administration of appropriate antibiotic therapy before and after implementation of prospective verification of antibiotics in the ED. This retrospective, institutional review board-approved preimplementation vs postimplementation study evaluated patients 18years or older who were started on IV antibiotics in the ED. Patients were excluded if pregnant, if the patient is a prisoner, if no cultures were drawn, or if the patient was transferred from an outside facility. Appropriate antibiotic therapy was based on empiric source-specific evidence-based guidelines, appropriate pharmacokinetic and pharmacodynamic properties, and microbiologic data. The primary end point was the time from ED arrival to administration of appropriate antibiotic therapy. Of the 1628 evaluated, 128 patients met the inclusion criteria (64 pre vs 64 post). Patients were aged 65.2±17.0years, with most of infections being pneumonia (44%) and urinary tract infections (18%) and most patients being noncritically ill. Time to appropriate antibiotic therapy was reduced in the postgroup vs pregroup (8.1±8.6 vs 15.2±22.8hours, respectively, P=.03). In addition, appropriate empiric antibiotics were initiated more frequently after the implementation (92% post vs 66% pre; P=.0001). There was no difference in mortality or length of stay between the 2 groups. Prompt administration of the appropriate antibiotics is imperative in patients with infections presenting to the ED. The impact of prospective verification of

  18. Health care utilization before and after an outpatient ED visit in older people.

    Science.gov (United States)

    Horney, Carolyn; Schmader, Kenneth; Sanders, Linda L; Heflin, Mitchell; Ragsdale, Luna; McConnell, Eleanor; Hocker, Michael; Hastings, S Nicole

    2012-01-01

    Older adults in the United States receive a significant amount of care in the emergency department (ED), yet the associations between ED and other types of health care utilization have not been adequately studied in this population. The goals of this study were to examine the relationships between health care use before and after an ED visit among older adults. This retrospective cohort study examined health care use among 308 patients 65 years or older discharged from a university-affiliated ED. Proportional-hazards models were used to assess the relationship between pre-ED health care use (primary care physician [PCP], specialist, ED, and hospital) and risk of return ED visits. Older ED patients in this study had visited other types of providers frequently in the previous year (median number of PCP and specialist visits, 4). Patients who used the ED on 2 or more occasions in the previous year were found to have visited their PCP more often than those without frequent ED use (median number of visits, 7.0 vs 4.0; P < .001). Despite more PCP use in this population, frequent ED use was associated with increased risk of a repeat ED visit (hazard ratio, 2.20; 95% confidence interval, 1.15-4.21), in models adjusted for demographics and health status. Older adults who use the ED are also receiving significant amounts of care from other sources; simply providing additional access to care may not improve outcomes for these vulnerable individuals. Published by Elsevier Inc.

  19. Direct interaction between the Arabidopsis disease resistance signaling proteins, EDS1 and PAD4.

    Science.gov (United States)

    Feys, B J; Moisan, L J; Newman, M A; Parker, J E

    2001-10-01

    The Arabidopsis EDS1 and PAD4 genes encode lipase-like proteins that function in resistance (R) gene-mediated and basal plant disease resistance. Phenotypic analysis of eds1 and pad4 null mutants shows that EDS1 and PAD4 are required for resistance conditioned by the same spectrum of R genes but fulfil distinct roles within the defence pathway. EDS1 is essential for elaboration of the plant hypersensitive response, whereas EDS1 and PAD4 are both required for accumulation of the plant defence-potentiating molecule, salicylic acid. EDS1 is necessary for pathogen-induced PAD4 mRNA accumulation, whereas mutations in PAD4 or depletion of salicylic acid only partially compromise EDS1 expression. Yeast two-hybrid analysis reveals that EDS1 can dimerize and interact with PAD4. However, EDS1 dimerization is mediated by different domains to those involved in EDS1-PAD4 association. Co-immunoprecipitation experiments show that EDS1 and PAD4 proteins interact in healthy and pathogen-challenged plant cells. We propose two functions for EDS1. The first is required early in plant defence, independently of PAD4. The second recruits PAD4 in the amplification of defences, possibly by direct EDS1-PAD4 association.

  20. Factors affecting ED length-of-stay in surgical critical care patients.

    Science.gov (United States)

    Davis, B; Sullivan, S; Levine, A; Dallara, J

    1995-09-01

    To determine what patient characteristics are associated with prolonged emergency department (ED) length-of-stay (LOS) for surgical critical care patients, the charts of 169 patients admitted from the ED directly to the operating room (OR) or intensive care unit (ICU) during a 6-week period in 1993 were reviewed. The ED record was reviewed for documentation of factors that might be associated with prolonged ED LOS, such as use of computed tomographic (CT), radiology special procedures, and the number of plain radiographs and consultants. ED LOS was considered to be the time from triage until a decision was made to admit the patient. Using a Cox proportional hazards model, use of CT and special procedures were the strongest independent predictors of prolonged ED length-of-stay. The number of plain radiographs and consultants had only a minimal effect. Use of a protocol-driven trauma evaluation system was associated with a shorter ED LOS. In addition to external factors that affect ED overcrowding, ED patient management decisions may also be associated with prolonged ED length-of-stay. Such ED-based factors may be more important in surgical critical care patients, whose overall ED LOS is affected more by the length of the ED work-up rather than the time spent waiting for a ICU bed or operating suite.

  1. EDS coal liquefaction process development. Phase V. EDS commercial plant study design update. Illinois coal. Volume 1. Main report

    Energy Technology Data Exchange (ETDEWEB)

    Epperly, W. R.

    1981-03-01

    The objectives of the Study Design Update (SDU) were to identify the technical issues facing a potential commercial-size EDS plant design; to provide a reliable basis for estimating the cost of EDS products; and to furnish research guidance to the EDS Project. The SDU consists of two distinct studies in which different processing schemes are used to produce the hydrogen and fuel gas required by the plant. These studies are referred to as the Base Case and the Market Flexibility Sensitivity Case. In the Base Case, hydrogen is generated by steam reforming of the light hydrocarbon gases produced in the plant. Fuel gas is generated by feeding the bottoms stream from the liquefaction section vacuum pipestill to a FLEXICOKING unit. In the FLEXICOKING unit reactor, the bottoms stream is converted to coke; additional liquid product is also recovered. The coke is converted to low-Btu fuel gas in the FLEXICOKING unit gasifier. In the Market Flexibility Sensitivity (MFS) Case, the bottoms stream from the vacuum pipestill is split, and about half is sent to the FLEXICOKING unit for recovery of additional liquid product and production of fuel gas. The remainder of the bottoms stream is converted to hydrogen in a Partial Oxidation Unit. Hence the MFS Case does not consume light hydrocarbon gases produced and they are available for sale. The study of these two cases has demonstrated the importance of bottoms process selection to the economics and thermal efficiency of an EDS plant. Volume 1 - Main Report has been developed to be a stand-alone document. Both the Base Case and Market Flexibility Sensitivity (MFS) Case are covered. This volume includes an overview and detailed case summaries. It also covers economics, product recovery factors, material and energy balances, cost estimates and enviromental considerations.

  2. Is EdF carrying things too far?; EdF va-t-il trop loin?

    Energy Technology Data Exchange (ETDEWEB)

    Jemain, A.; Rouaud, P.O.

    2002-06-01

    Considered as too fast, too dispersed and financially too hazardous, the recent series of acquisitions of Electricite de France (EdF) oblige the French government to make short work of the statute of the French electrical utility. This situation increases the debt of the company and constrains its captive clients (domestic clients and small and medium size companies) to contribute to this unlimited expansionism by paying their electricity a higher price. (J.S.)

  3. APP with Kunitz type protease inhibitor domain (KPI) correlates with neuritic plaque density but not with cortical synaptophysin immunoreactivity in Alzheimer's disease and non-demented aged subjects: a multifactorial analysis.

    Science.gov (United States)

    Zhan, S S; Sandbrink, R; Beyreuther, K; Schmitt, H P

    1995-01-01

    The formation of beta A4 amyloid protein in neuritic plaques in Alzheimer's disease (AD) and advanced age is a complex process that involves a number of both cellular and molecular mechanisms, the interrelations of which are not yet completely understood. We have examined quantitatively, in AD and aged controls an extended spectrum of amyloid plaque-related cellular and molecular factors and the cortical synaptophysin immunoreactivity (synaptic density) in order to check for interrelations between them by multifactorial analysis. In 3 cases of senile dementia of the Alzheimer type (SDAT) aged 72, 80 and 82 years, and 9 controls aged 43-88 (mean age 65) years, the cortical synaptophysin immunoreactivity was assessed, together with the numbers of neurons, astrocytes and microglial cells, senile plaques, of tangle-bearing neurons, and the amount of beta A4 amyloid precursor protein (APP) with and without the Kunitz type serine protease inhibitor (KPI) domain. The main results were: APP including the KPI domain (KPI-APP) correlated with the number of neuritic plaques, regardless of whether they occurred in SDAT or non-demented controls. There was no significant difference in the amount of KPI-APP between SDAT and controls. Conversely, APP695 (without KPI) was significantly reduced in SDAT. KPI-APP did not correlate with the synaptophysin immunoreactivity (RGVA), while APP695 showed a significant correlation with the latter in all evaluations. It also correlated with the neuron counts, which was not true for KPI-APP. These results support previous findings indicating that KPI-APP is an important local factor for amyloid deposition in the neuritic plaques, both in AD and in non-demented aged people. On the contrary, KPI-APP does not seem to be significantly involved in the mechanisms of synaptic change outside of the plaques.

  4. Evaluación de la cognición social y teoría de la mente en pacientes con enfermedad cerebelosa degenerativa aislada no dementes Social cognition and theory of mind assessment in non-demented patients with isolated cerebellar degeneration

    Directory of Open Access Journals (Sweden)

    Carlos G. Abel

    2007-06-01

    Full Text Available OBJETIVO: Investigar la hipótesis según la cual, el cerebelo podría participar en las alteraciones de la cognición social (CS. MÉTODO: Se administraron tests neuropsicológicos generales, de función ejecutiva (FE, de CS que evaluaban la capacidad de inferir el estado mental de otras personas y la escala de Depresión de Beck a 10 pacientes adultos con enfermedad cerebelosa adquirida aislada (GEC y a 10 controles (GCO apareados por edad, sexo y educación. Se analizaron los datos mediante ANOVA y correlación. RESULTADOS: El GEC obtuvo puntajes significativamente menores (p?0,05 que el grupo GCO en tareas de FE (Test de Wisconsin y preguntas de creencia (PCr de Teoría de la Mente (ToM. El rendimiento en las preguntas de control (PCo de ToM fue similar en ambos grupos. El menor rendimiento en las PCr correlacionó significativamente con una menor habilidad conceptual, la severidad de la apatía (NPI y de la ataxia estática. Las PCo correlacionaron con medidas de atención y de recuerdo diferido libre. CONCLUSÍON: El cerebelo contribuiría en el monitoreo de la conducta mediante el control de datos multimodales motores, cognitivos y emocionales.AIM: To investigate whether the cerebellum could participate in social cognition (SC. METHOD: General neuropsychological tests, executive tests (EF, social cognition tests, which assess the ability to infer other peoples’ mental states, and the Beck Depression Inventory were given to 10 non-demented patients with isolated cerebellar degenerative disease, and to 10 healthy controls matched for sex, age, and years of education. ANOVA and correlation coefficients were employed for the statistical analysis. RESULTS: Patients within the cerebellar group were significantly impaired (p?0.05 in EF test [Wisconsin Card Sorting Test (WSCT] and belief questions (BQ from Theory of Mind (ToM tests. Performance in control questions (CQ from ToM tests was similar for both groups. Lower scores in BQ correlated

  5. In-situ investigation of laser surface modifications of WC-Co hard metals inside a scanning electron microscope

    Science.gov (United States)

    Mueller, H.; Wetzig, K.; Schultrich, B.; Pompe, Wolfgang; Chapliev, N. I.; Konov, Vitaly I.; Pimenov, S. M.; Prokhorov, Alexander M.

    1989-05-01

    The investigation of laser interaction with solid surfaces and of the resulting mechanism of surface modification are of technical interest to optimize technological processes, and they are also of fundamental scientific importance. Most instructive indormation is available with the ail of the in-situ techniques. For instance, measuring of the photon emission of the irradiated surface ane the plasma torch (if it is produced) simultaneously to laser action, makes it possible to gain a global characterization of the laser-solid interaction. In order to obtain additional information about surface and structure modifications in microscopic detail , a laser and scanning electron microscope were combined in to a tandem equipment (LASEM). Inside this eqiipment the microscopic observation is carried out directly at the laser irradiated area without any displacement of the sample. In this way, the stepwise development of surface modification during multipulse irradiation is visible in microscopic details and much more reliable information about the surface modification process is obtainable in comparison to an external laser irradiation. Such kind of equipments were realized simultaneously and independently in the Institut of General Physics (Moscow) and the Central Institute of Solid State Physics and Material Research (Dresden) using a CO2 and a LTd-glass-laser, respectively. In the following the advantages and possibilities of a LASEM shall be demonstrated by some selected investigations of WC-CO hardmeta. The results were obtained in collaboration by both groups with the aid of the pulsed CO2-laser. The TEA CO2 laser was transmitted through a ZnSe-window into the sample chamber of the SEM and focused ofAo tfte sample surface. It was operated in TEM - oo mode with a repetition rate of about 1 pulse per second. A peak power density of about 160 MW/cm2 was achieved in front of the sample surface.

  6. Does the Op-Ed Page Have a Chance to Become a Public Forum?

    Science.gov (United States)

    Ciofalo, Andrew; Traverso, Kim

    1994-01-01

    Surveys op-ed page editors, finding that fewer than half of the responding papers have op-ed pages; that professional journalists, public figures, and propagandists dominate the pages; and that editors firmly control the agenda. (SR)

  7. A functional EDS1 ortholog is differentially regulated in powdery mildew resistant and susceptible grapevines and complements an Arabidopsis eds1 mutant.

    Science.gov (United States)

    Gao, Fei; Shu, Xiaomei; Ali, Mohammad Babar; Howard, Susanne; Li, Nan; Winterhagen, Patrick; Qiu, Wenping; Gassmann, Walter

    2010-04-01

    Vitis vinifera (grapevine) is the most economically important deciduous fruit crop, but cultivated grapevine varieties lack adequate innate immunity to a range of devastating diseases. To identify genetic resources for grapevine innate immunity and understand pathogen defense pathways in a woody perennial plant, we focus in this study on orthologs of the central Arabidopsis thaliana defense regulator ENHANCED DISEASE SUSCEPTIBILITY1 (EDS1). The family of EDS1-like genes is expanded in grapevine, and members of this family were previously found to be constitutively upregulated in the resistant variety 'Norton' of the North American grapevine species Vitis aestivalis, while they were induced by Erysiphe necator, the causal agent of grapevine powdery mildew (PM), in the susceptible V. vinifera variety 'Cabernet Sauvignon'. Here, we determine the responsiveness of individual EDS1-like genes in grapevine to PM and salicylic acid, and find that EDS1-like paralogs are differentially regulated in 'Cabernet Sauvignon', while two are constitutively upregulated in 'Norton'. Sequencing of VvEDS1 and VaEDS1 cDNA and genomic clones revealed high conservation in the protein-encoding sequence and some divergence of the promoter sequence in the two grapevine varieties. Complementation of the Arabidopsis eds1-1 mutant showed that the EDS1-like gene with highest predicted amino acid sequence similarity to AtEDS1 from either grapevine varieties is a functional ortholog of AtEDS1. Together, our analyses show that differential susceptibility to PM is correlated with differences in EDS1 expression, not differences in EDS1 function, between resistant 'Norton' and susceptible 'Cabernet Sauvignon'.

  8. A Successful ED Fall Risk Program Using the KINDER 1 Fall RiskAssessment Tool.

    Science.gov (United States)

    Townsend, Ann B; Valle-Ortiz, Marisol; Sansweet, Tracy

    2016-11-01

    Emergency nurses did not perform falls risk assessments routinely on our ED patients; the instrument used was aimed at inpatients. We identified a need to revise fall assessment practices specific to our emergency department. The purpose of the performance improvement project was to reduce ED falls and evaluate the use of an ED-specific fall risk tool, the KINDER 1 Fall Risk Assessment. The plan was to establish fall risk assessment practices at point of ED entry and to decrease total falls.

  9. Molecular cloning and characterization of enhanced disease susceptibility 1 (EDS1) from Gossypium barbadense.

    Science.gov (United States)

    Su, Xiaofeng; Qi, Xiliang; Cheng, Hongmei

    2014-06-01

    Arabidopsis enhanced disease susceptibility 1 (EDS1) plays an important role in plant defense against biotrophic and necrotrophic pathogens. The necrotrophic pathogen Verticillium dahliae infection of Gossypium barbadense could lead to Verticillium wilt which seriously reduces the cotton production. Here, we cloned and characterized a G. barbadense homolog of EDS1, designated as GbEDS1. The full-length cDNA of the GbEDS1 gene was obtained by the technique of rapid-amplification of cDNA ends. The open reading frame of the GbEDS1 gene was 1,647 bp long and encoded a protein of 548 amino acids residues. Comparison of the cDNA and genomic DNA sequence of GbEDS1 indicated that this gene contained a single intron and two exons. Like other EDS1s, GbEDS1 contained a conserved N-terminal lipase domain and an EDS1-specific KNEDT motif. Subcellular localization assay revealed that GbEDS1-green fluorescence protein fusion protein was localized in both cytosol and nucleus. Interestingly, the transcript levels of GbEDS1 were dramatically increased in response to pathogen V. dahliae infection. To investigate the role of GbEDS1 in plant resistance against V. dahliae, a conserved fragment derived from GbEDS1 was used to knockdown the endogenous EDS1 in Nicotiana benthamiana by heterologous virus-induced gene silencing. Our data showed that silencing of NbEDS1 resulted in increased susceptibility to V. dahliae infection in N. benthamiana, suggesting a possible involvement of the novelly isolated GbEDS1 in the regulation of plant defense against V. dahliae.

  10. Treatment of Nausea and Vomiting in Pregnancy: Factors Associated with ED Revisits

    Directory of Open Access Journals (Sweden)

    Brian R. Sharp

    2016-09-01

    Full Text Available Introduction: Nausea and vomiting in pregnancy (NVP is a condition that commonly affects women in the first trimester of pregnancy. Despite frequently leading to emergency department (ED visits, little evidence exists to characterize the nature of ED visits or to guide its treatment in the ED. Our objectives were to evaluate the treatment of NVP in the ED and to identify factors that predict return visits to the ED for NVP. Methods: We conducted a retrospective database analysis using the electronic medical record from a single, large academic hospital. Demographic and treatment variables were collected using a chart review of 113 ED patient visits with a billing diagnosis of “nausea and vomiting in pregnancy” or “hyperemesis gravidarum.” Logistic regression analysis was used with a primary outcome of return visit to the ED for the same diagnoses. Results: There was wide treatment variability of nausea and vomiting in pregnancy patients in the ED. Of the 113 patient visits, 38 (33.6% had a return ED visit for NVP. High gravidity (OR 1.31, 95% CI [1.06-1.61], high parity (OR 1.50 95% CI [1.12-2.00], and early gestational age (OR 0.74 95% CI [0.60-0.90] were associated with an increase in return ED visits in univariate logistic regression models, while only early gestational age (OR 0.74 95% CI [0.59-0.91] was associated with increased return ED visits in a multiple regression model. Admission to the hospital was found to decrease the likelihood of return ED visits (p=0.002. Conclusion: NVP can be difficult to manage and has a high ED return visit rate. Optimizing care with aggressive, standardized treatment in the ED and upon discharge, particularly if factors predictive of return ED visits are present, may improve quality of care and reduce ED utilization for this condition.

  11. Treatment of Nausea and Vomiting in Pregnancy: Factors Associated with ED Revisits

    Science.gov (United States)

    Sharp, Brian R.; Sharp, Kristen M.; Patterson, Brian; Dooley-Hash, Suzanne

    2016-01-01

    Introduction Nausea and vomiting in pregnancy (NVP) is a condition that commonly affects women in the first trimester of pregnancy. Despite frequently leading to emergency department (ED) visits, little evidence exists to characterize the nature of ED visits or to guide its treatment in the ED. Our objectives were to evaluate the treatment of NVP in the ED and to identify factors that predict return visits to the ED for NVP. Methods We conducted a retrospective database analysis using the electronic medical record from a single, large academic hospital. Demographic and treatment variables were collected using a chart review of 113 ED patient visits with a billing diagnosis of “nausea and vomiting in pregnancy” or “hyperemesis gravidarum.” Logistic regression analysis was used with a primary outcome of return visit to the ED for the same diagnoses. Results There was wide treatment variability of nausea and vomiting in pregnancy patients in the ED. Of the 113 patient visits, 38 (33.6%) had a return ED visit for NVP. High gravidity (OR 1.31, 95% CI [1.06–1.61]), high parity (OR 1.50 95% CI [1.12–2.00]), and early gestational age (OR 0.74 95% CI [0.60–0.90]) were associated with an increase in return ED visits in univariate logistic regression models, while only early gestational age (OR 0.74 95% CI [0.59–0.91]) was associated with increased return ED visits in a multiple regression model. Admission to the hospital was found to decrease the likelihood of return ED visits (p=0.002). Conclusion NVP can be difficult to manage and has a high ED return visit rate. Optimizing care with aggressive, standardized treatment in the ED and upon discharge, particularly if factors predictive of return ED visits are present, may improve quality of care and reduce ED utilization for this condition. PMID:27625723

  12. EDS1 mediates pathogen resistance and virulence function of a bacterial effector in soybean

    Science.gov (United States)

    Enhanced disease susceptibility 1 (EDS1) and phytoalexin deficient 4 (PAD4) are well known regulators of both basal and resistance (R) protein-mediated plant defense. We identified two EDS1- (GmEDS1a/b) and one PAD4-like (GmPAD4) protein that are required for resistance signaling in soybean. Consist...

  13. EDS V26 Containment Vessel Explosive Qualification Test Report

    Energy Technology Data Exchange (ETDEWEB)

    Crocker, Robert W. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Haroldsen, Brent L. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Stofleth, Jerome H. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2013-11-01

    The objective of the test was to qualify the vessel for its intended use by subjecting it to a 1.25 times overtest. The criteria for success are that the measured strains do not exceed the calculated strains from the vessel analysis, there is no significant additional plastic strain on subsequent tests at the rated design load (shakedown), and there is no significant damage to the vessel and attached hardware that affect form, fit, or function. Testing of the V25 Vessel in 2011 established a precedent for testing V26 [2]. As with V25, two tests were performed to satisfy this objective. The first test used 9 pounds of Composition C-4 (11.25 lbs. TNT-equivalent), which is 125 percent of the design basis load. The second test used 7.2 pounds of Composition C-4 (9 lbs. TNT-equivalent) which is 100 percent of the design basis load. The first test provided the required overtest while the second test served to demonstrate shakedown and the absence of additional plastic deformation. Unlike the V25 vessel, which was mounted in a shipping cradle during testing, the V26 vessel was mounted on the EDS P2U3 trailer prior to testing. Visual inspections of the EDS vessel, surroundings, and diagnostics were completed before and after each test event. This visual inspection included analyzing the seals, fittings, and interior surfaces of the EDS vessel and documenting any abnormalities or damages. Photographs were used to visually document vessel conditions and findings before and after each test event.

  14. Esther Schor, ed. The Cambridge Companion to Mary Shelley

    Directory of Open Access Journals (Sweden)

    Anne BERTON

    2006-06-01

    Full Text Available “Today, whether she is found between staid cloth covers, in paperback, on the screen or in cyberspace, Mary Shelley is everywhere,” writes Esther Schor in her Introduction to this collection of essays (2. Interest in “the Author of Frankenstein” and of other works has grown steadily over the last twenty years, thanks notably to the publication of her Journals (The Journals of Mary Shelley, 1814-1844, ed. Paula R. Feldman and Diana Scott-Kilvert, 2 vols, Oxford: Clarendon, 1987, of her Lette...

  15. Book Review: Digital Forensic Evidence Examination (2nd ed.)

    OpenAIRE

    Gary Kessler

    2010-01-01

    Cohen, F. (2010). Digital Forensic Evidence Examination (2nd ed.). Livermore, CA: ASP Press. 452 pages, ISBN: 978-1-878109-45-3, US$79.Reviewed by Gary C. Kessler, Gary Kessler Associates & Edith Cowan University ()On the day that I sat down to start to write this review, the following e-mailcame across on one of my lists:Person A and Person B write back and forth and create an email thread. Person A then forwards the email to Person C, but changes some wording in the e...

  16. Effects of Carbon Content and B Class Porosity on Bending Strength of WC-8% Co Cemented Carbide%碳量及B类孔隙对WC-8%Co硬质合金抗弯强度的影响

    Institute of Scientific and Technical Information of China (English)

    闵召宇; 廖军; 时凯华; 蒋阳

    2013-01-01

    采用粉末冶金方法制备了WC-8%Co硬质合金试样,经氢气烧结后,利用钴磁测试仪、强度测试仪、电子显微镜和金相显微镜分别对试样的钴磁和抗弯强度进行测定、对试样断口和金相缺陷进行观察.研究了WC-8%Co硬质合金抗弯强度与碳量(相对磁饱和)、金相缺陷(B类孔隙)之间的关系.结果表明:将试样碳含量及孔隙度控制在一定的范围内,可以使试样抗弯强度保持在较高的水平,当试样相对磁饱和为88%~92%,B类孔隙为B00时,合金显微组织中WC晶粒较为均匀,无异常长大情况,WC-8%Co硬质合金抗弯强度可达3 286 N/mm2;同时,抗弯强度值的大小随孔隙度的增多而下降.另外,氢气烧结后经HIP处理可以有效消除WC-8%Co硬质合金中的孔隙缺陷,从而提高合金抗弯强度,经HIP处理的试样的强度比正常样的强度高出2.3%.%WC-8%Co cemented carbide specimens were prepared by powder metallurgy method. The cobalt magnetism and bending strength of the specimens were tested. The fracture surface and the defects in the microstructure were observed. Furthermore the effects of the carbon content (relative magnetic saturation) and the defects (B class pores) on the bending strength of the cemented carbide were studied. The results show that by means of controlling the carbon content and the porosity in the certain ranges, the bending strength of the WC-8%Co cemented carbide remains at a high level. When the relative magnetic saturation is in the range of 88%~92% and the metallographic B class porosity is BOO, the WC grain size of WC-8% Co is more uniform and the bending strength of the cemented carbide reaches its highest values at 3 286 N/mm2. Meanwhile, the bending strength value decreases with the increasing of porosity. In addition, HIP treatment after hydrogen sintering can effectively eliminate pore defects in the WC-8%Co cemented carbide, thus the bending strength is enhanced up to 2.3%.

  17. Constitutive disease resistance requires EDS1 in the Arabidopsis mutants cpr1 and cpr6 and is partially EDS1-dependent in cpr5.

    Science.gov (United States)

    Clarke, J D; Aarts, N; Feys, B J; Dong, X; Parker, J E

    2001-05-01

    The systemic acquired resistance (SAR) response in Arabidopsis is characterized by the accumulation of salicylic acid (SA), expression of the pathogenesis-related (PR) genes, and enhanced resistance to virulent bacterial and oomycete pathogens. The cpr (constitutive expressor of PR genes) mutants express all three SAR phenotypes. In addition, cpr5 and cpr6 induce expression of PDF1.2, a defense-related gene associated with activation of the jasmonate/ethylene-mediated resistance pathways. cpr5 also forms spontaneous lesions. In contrast, the eds1 (enhanced disease susceptibility) mutation abolishes race-specific resistance conferred by a major subclass of resistance (R) gene products in response to avirulent pathogens. eds1 plants also exhibit increased susceptibility to virulent pathogens. Epistasis experiments were designed to explore the relationship between the cpr- and EDS1-mediated resistance pathways. We found that a null eds1 mutation suppresses the disease resistance phenotypes of both cpr1 and cpr6. In contrast, eds1 only partially suppresses resistance in cpr5, leading us to conclude that cpr5 expresses both EDS1-dependent and EDS1-independent components of plant disease resistance. Although eds1 does not prevent lesion formation on cpr5 leaves, it alters their appearance and reduces their spread. This phenotypic difference is associated with increased pathogen colonization of cpr5 eds1 plants compared to cpr5. The data allow us to place EDS1 as a necessary downstream component of cpr1- and cpr6-mediated responses, but suggest a more complex relationship between EDS1 and cpr5 in plant defense.

  18. Domestic violence in an inner-city ED.

    Science.gov (United States)

    Ernst, A A; Nick, T G; Weiss, S J; Houry, D; Mills, T

    1997-08-01

    A confidential written survey was conducted at the emergency department (ED) of Charity Hospital in New Orleans to determine the prevalence of domestic violence (DV) for male and female ED patients and to determine the demographics of DV. Four violence parameters were calculated for patients who had a partner at the time of presentation: 1) present physical; 2) present nonphysical; 3) past physical; and 4) past nonphysical. Out of the 516 patients enrolled, 283 were women and 233 were men. On the basis of Index of Spouse Abuse scoring, 14% of men and 22% of women had experienced past nonphysical violence, and 28% of men and 33% of women had experienced past physical violence. Of the 157 men and 207 women with partners at the time of presentation, 11% men and 15% women reported present nonphysical violence, and 20% men and 19% of the women reported present physical violence. Logistic-regression models demonstrated that women experienced significantly more past and present nonphysical violence but not physical violence than men. Alcohol, drug use, and suicidal ideation were found to be significant predictors associated with DV. In conclusion, DV rates were high in the New Orleans population, with nearly equal rates of past and present physical violence for men and women.

  19. The collection of MicroED data for macromolecular crystallography.

    Science.gov (United States)

    Shi, Dan; Nannenga, Brent L; de la Cruz, M Jason; Liu, Jinyang; Sawtelle, Steven; Calero, Guillermo; Reyes, Francis E; Hattne, Johan; Gonen, Tamir

    2016-05-01

    The formation of large, well-ordered crystals for crystallographic experiments remains a crucial bottleneck to the structural understanding of many important biological systems. To help alleviate this problem in crystallography, we have developed the MicroED method for the collection of electron diffraction data from 3D microcrystals and nanocrystals of radiation-sensitive biological material. In this approach, liquid solutions containing protein microcrystals are deposited on carbon-coated electron microscopy grids and are vitrified by plunging them into liquid ethane. MicroED data are collected for each selected crystal using cryo-electron microscopy, in which the crystal is diffracted using very few electrons as the stage is continuously rotated. This protocol gives advice on how to identify microcrystals by light microscopy or by negative-stain electron microscopy in samples obtained from standard protein crystallization experiments. The protocol also includes information about custom-designed equipment for controlling crystal rotation and software for recording experimental parameters in diffraction image metadata. Identifying microcrystals, preparing samples and setting up the microscope for diffraction data collection take approximately half an hour for each step. Screening microcrystals for quality diffraction takes roughly an hour, and the collection of a single data set is ∼10 min in duration. Complete data sets and resulting high-resolution structures can be obtained from a single crystal or by merging data from multiple crystals.

  20. Improving ED specimen TAT using Lean Six Sigma.

    Science.gov (United States)

    Sanders, Janet H; Karr, Tedd

    2015-01-01

    Lean and Six Sigma are continuous improvement methodologies that have garnered international fame for improving manufacturing and service processes. Increasingly these methodologies are demonstrating their power to also improve healthcare processes. The purpose of this paper is to discuss a case study for the application of Lean and Six Sigma tools in the reduction of turnaround time (TAT) for Emergency Department (ED) specimens. This application of the scientific methodologies uncovered opportunities to improve the entire ED to lab system for the specimens. This case study provides details on the completion of a Lean Six Sigma project in a 1,000 bed tertiary care teaching hospital. Six Sigma's Define, Measure, Analyze, Improve, and Control methodology is very similar to good medical practice: first, relevant information is obtained and assembled; second, a careful and thorough diagnosis is completed; third, a treatment is proposed and implemented; and fourth, checks are made to determine if the treatment was effective. Lean's primary goal is to do more with less work and waste. The Lean methodology was used to identify and eliminate waste through rapid implementation of change. The initial focus of this project was the reduction of turn-around-times for ED specimens. However, the results led to better processes for both the internal and external customers of this and other processes. The project results included: a 50 percent decrease in vials used for testing, a 50 percent decrease in unused or extra specimens, a 90 percent decrease in ED specimens without orders, a 30 percent decrease in complete blood count analysis (CBCA) Median TAT, a 50 percent decrease in CBCA TAT Variation, a 10 percent decrease in Troponin TAT Variation, a 18.2 percent decrease in URPN TAT Variation, and a 2-5 minute decrease in ED registered nurses rainbow draw time. This case study demonstrated how the quantitative power of Six Sigma and the speed of Lean worked in harmony to improve

  1. Evaluación de las transformaciones estructurales en recubrimientos de WC10Ni depositados por laser cladding sobre acero para herramienta EN 12379

    Directory of Open Access Journals (Sweden)

    Candel, J. J.

    2011-08-01

    Full Text Available Carbide metal matrix composite materials are known for a high resistance to all types of wear. It is due to a beneficial combination of properties given by hard phase particles included in a tough matrix. Different kinds of those materials have been employed in the development of new high properties cutting tools. Laser cladding (LC technique allows obtaining an accurate defect-free coating with a low thermal affectation of the component. But in the case of WC cermet coatings due to its high laser absorption and the different mechanical and thermal properties between substrate and coating can appear a wide range of different defects as cracks, pores, massive carbide dilution and lacks of adherence. The aim of the present work is to study the metallurgical transformations during LC process of WC cermet coating on cold work tool steel substrate (EN 12379. Also it has been related process parameters with defects generation. Microstructure and composition of the coating and the heat affected zone have been analysed. Microhardness evolution profile has been obtained. Results show that although process parameters control reduce the generation of defects, in the deposition of overlapped layers appear different metallurgical transformations related with massive WC decomposition and the diffusion of alloying elements from substrate to the coating.

    Los materiales compuestos de matriz metálica reforzados con carburos, son conocidos por su elevada resistencia a todos los tipos de desgaste, debido a la combinación de las partículas duras en una matriz metálica tenaz. Diferentes tipos de estos materiales, se han empleado en el desarrollo de nuevas herramientas de corte de altas prestaciones. La técnica de láser cladding (LC, permite obtener recubrimientos libres de defectos sobre zonas muy concretas, con un aporte de calor muy localizado. Pero en el caso de carburos de wolframio (WC, debido a la enorme absorción de energía y la

  2. Registered Nurses and Discharge Planning in a Taiwanese ED: A Neglected Issue?

    Science.gov (United States)

    Chang, Wen; Goopy, Suzanne; Lin, Chun-Chih; Barnard, Alan; Liu, Hsueh-Erh; Han, Chin-Yen

    2016-10-01

    Published research on discharge planning is written from the perspective of hospital wards and community services. Limited research focuses on discharge planning in the emergency department (ED). The objective of this study was to identify ED nurses' perceptions of factors influencing the implementation of discharge planning. This qualitative study collected data from 25 ED nurses through in-depth interviews and a drawing task in which participants were asked to depict on paper the implementation of discharge planning in their practice. Factors influencing discharge planning were grouped into three categories: discharge planning as a neglected issue in the ED, heavy workload, and the negative attitudes of ED patients and their families. The study highlighted a need for effective discharge planning to be counted as an essential clinical competency for ED nurses and factored into their everyday workload. Nurses perceived that organizational culture, and parents' and relatives' attitudes were barriers to implementing discharge teaching in the ED.

  3. 激光重熔WC复合陶瓷涂层组织及耐腐蚀性能%Ceramic Coating of WC-Co-NiCrAl/Laser-Remelting Microstructure and Corrosion Characteristics

    Institute of Scientific and Technical Information of China (English)

    花国然; 龚晓燕; 居志兰; 田宗军; 赵剑峰; 黄因慧

    2010-01-01

    在45号钢表面,制备了WC/Co-NiCrAl等离子喷涂涂层(TC-1)和WC/Co-NiCrAl/laser-remelting激光直接重熔等离子喷涂陶瓷涂层(TC-2).以纳米SiC粉末为填料,对等离子喷涂层TC-1进行了填料下的激光重熔,制备了纳米SiC改性的WC/Co-NiCrAl/nano-SiC复合陶瓷涂层(TC-3).采用X射线衍射、扫描电镜对三种涂层微观组织进行了分析,同时对陶瓷涂层的耐腐蚀性能进行了研究.结果表明,TC-1涂层由WC,W2C,W6C2.54,W,Co,CoO组成; TC-2重熔涂层由WC,W2C,CoO及W组成;纳米改性后的重熔涂层TC-3由SiC,Si2W,WC,W及CoO组成.在激光作用下,原等离子喷涂层WC/Co的片层状组织得以消除.与TC-1涂层相比,TC-2及TC-3陶瓷涂层致密化程度明显提高,涂层耐腐蚀性能也得到了明显的改善.

  4. Safety of the recombinant cholera toxin B subunit, killed whole-cell (rBS-WC oral cholera vaccine in pregnancy.

    Directory of Open Access Journals (Sweden)

    Ramadhan Hashim

    Full Text Available Mass vaccinations are a main strategy in the deployment of oral cholera vaccines. Campaigns avoid giving vaccine to pregnant women because of the absence of safety data of the killed whole-cell oral cholera (rBS-WC vaccine. Balancing this concern is the known higher risk of cholera and of complications of pregnancy should cholera occur in these women, as well as the lack of expected adverse events from a killed oral bacterial vaccine.From January to February 2009, a mass rBS-WC vaccination campaign of persons over two years of age was conducted in an urban and a rural area (population 51,151 in Zanzibar. Pregnant women were advised not to participate in the campaign. More than nine months after the last dose of the vaccine was administered, we visited all women between 15 and 50 years of age living in the study area. The outcome of pregnancies that were inadvertently exposed to at least one oral cholera vaccine dose and those that were not exposed was evaluated. 13,736 (94% of the target women in the study site were interviewed. 1,151 (79% of the 1,453 deliveries in 2009 occurred during the period when foetal exposure to the vaccine could have occurred. 955 (83% out of these 1,151 mothers had not been vaccinated; the remaining 196 (17% mothers had received at least one dose of the oral cholera vaccine. There were no statistically significant differences in the odds ratios for birth outcomes among the exposed and unexposed pregnancies.We found no statistically significant evidence of a harmful effect of gestational exposure to the rBS-WC vaccine. These findings, along with the absence of a rational basis for expecting a risk from this killed oral bacterial vaccine, are reassuring but the study had insufficient power to detect infrequent events.ClinicalTrials.gov NCT00709410.

  5. BMI, WC, WHtR, VFI and BFI: which indictor is the most efficient screening index on type 2 diabetes in Chinese community population.

    Science.gov (United States)

    Mi, Sheng Quan; Yin, Peng; Hu, Nan; Li, Jian Hong; Chen, Xiao Rong; Chen, Bo; Yan, Liu Xia; Zhao, Wen Hua

    2013-06-01

    Obesity is a major risk factor for type 2 diabetes, many indexes can be used to describes obesity and predict diabetes. This research attempts to identify the best indicator of obesity to screening diabetes in Chinese population. A cross-sectional data of 8121 subjects aged 35-60 years were included in this research belongs to the Diabetes Appropriate Technology Intervention Study. Anthropometric indicators including body weight, height, waist circumferences (WC), body fat index (BFI) and visceral fat index (VFI) and blood biochemical indicators after an overnight fast [fasting blood glucose, total cholesterol, high-density lipoprotein (HDL) cholesterol, and triacylglycerol] were measured. BMI (body mass index) and Weight to Height Ratio was calculated. Subjects with obesity had a higher risk of physician diagnosed diabetes (OR=2.50, 95% CI 1.83-3.43), new diagnosed diabetes (OR=4.23, 95% CI 2.91-6.15) and pre-diabetes (OR=1.75, 95% CI 1.31-2.34) compared to those with normal Body mass index (BMI). There was a significant trend of increased risk of all diabetes status with increased waist circumference (WC). The waist-to-height ratio (WHtR) yielded the most significant association with new diagnosed diabetes and physician diagnosed diabetes than other indices. Central obesity is significantly correlated with diabetes. VFI was most correlated with pre-diabetes while WHtR is an efficient screening index than BMI and WC in Chinese community diabetes screening. Copyright © 2013 The Editorial Board of Biomedical and Environmental Sciences. Published by China CDC. All rights reserved.

  6. Degradación de la resistencia a fractura de un carburo cementado WC-Ni sometido a choque térmico

    OpenAIRE

    2015-01-01

    Los carburos cementados son materiales compuestos por carburos (generalmente de WC) incrustados en una matriz metálica (normalmente de cobalto) que actúa como ligante. Estos materiales se caracterizan por unas excelentes propiedades mecánicas gracias a la combinación de la dureza y resistencia al desgaste de las partículas cerámicas con la tenacidad de la fase metálica. Sin embargo, problemas como el alto precio del cobalto, su toxicidad y la exigencia del mercado que demanda nuevos materiale...

  7. Mathematical modelling in Matlab of the experimental results shows the electrochemical potential difference - temperature of the WC coatings immersed in a NaCl solution

    Science.gov (United States)

    Benea, M. L.; Benea, O. D.

    2016-02-01

    The method used for purchasing the corrosion behaviour the WC coatings deposited by plasma spraying, on a martensitic stainless steel substrate consists in measuring the electrochemical potential of the coating, respectively that of the substrate, immersed in a NaCl solution as corrosive agent. The mathematical processing of the obtained experimental results in Matlab allowed us to make some correlations between the electrochemical potential of the coating and the solution temperature is very well described by some curves having equations obtained by interpolation order 4.

  8. SEM-EDS analysis and discrimination of forensic soil.

    Science.gov (United States)

    Cengiz, Salih; Cengiz Karaca, Ali; Cakir, Ismail; Bülent Uner, H; Sevindik, Aytekin

    2004-04-20

    Soils vary among different areas, and have some characteristics because of the natural effects and transfers made by human and other living beings in time. So that forensic examination of soil is not only concerned with the analysis of naturally occurring rocks, minerals, vegetation, and animal matter. It also includes the detection of such manufactured materials such as ions from synthetic fertilizers and from different environments (e.g., nitrate, phosphate, and sulfate) as environmental artifacts (e.g., lead or objects as glass, paint chips, asphalt, brick fragments, and cinders) whose presence may impart soil with characteristics that will make it unique to a particular location. Many screening and analytical methods have been applied for determining the characteristics which differentiate and discriminate the forensic soil samples but none of them easily standardized. Some of the methods that applied in forensic laboratories in forensic soil discrimination are the color comparison of the normal air-dried (dehumidified) and overheated soil samples, macroscopic observation, and low-power stereo-microscopic observation, determination of anionic composition by capillary electrophoresis (CE), and the elemental composition by scanning electron microscope (SEM)-energy dispersive X-ray spectrometer (EDS) and other high sensitivity techniques. The objective of this study was to show the effect of the application of 9 tonnes/cm2 pressure on the elemental compositions obtained by SEM-EDS technique and comparing the discrimination power of the pressed-homogenized and not homogenized forensic soil samples. For this purpose soil samples from 17 different locations of Istanbul were collected. Aliquots of the well mixed samples were dried in an oven at 110-120 degrees C and sieved by using 0.5 mm sieve and then the undersieve fraction(JEO-JSM-5600 equipped with an energy dispersive X-ray spectrometer OXFORD Link-ISIS-300. The samples from top of the sieves were examined with

  9. Prevalence and correlates of erectile dysfunction (ED) and treatment seeking for ED in Asian Men: the Asian Men's Attitudes to Life Events and Sexuality (MALES) study.

    Science.gov (United States)

    Tan, Hui-Meng; Low, Wah Yun; Ng, Chirk Jenn; Chen, Kuang-Kuo; Sugita, Minoru; Ishii, Nobuhisa; Marumo, Ken; Lee, Sung Won; Fisher, William; Sand, Michael

    2007-11-01

    There have been limited multiregional studies in Asia examining the parameters of men's general and sexual health and quality of life in the general population vs. those in clinical cohorts of patients with erectile dysfunction (ED). The aims of the Asian Men's Attitudes to Life Events and Sexuality (Asian MALES) study were to investigate the prevalence of ED, associated health conditions, and ED treatment-seeking patterns in the general male population in five regions of Asia (China, Japan, Korea, Malaysia, and Taiwan). Standardized questionnaire previously used in a similar multiregional study and modified to ensure culturally appropriate content for Asia. Phase I of the study involved 10,934 adult men, aged 20-75 years, who were interviewed using the standardized questionnaire. Phase II of the study involved men with self-reported ED recruited from Phase I and via physician referral, invitations in general practitioner offices, and street interception (total Phase II sample, N = 1,209). The overall prevalence of self-reported ED in the Phase I study population was 6.4%. ED prevalence varied by region and significantly increased with age (P influencer of treatment seeking in all regions except Malaysia. The findings confirm those of existing research on ED in both Asian and non-Asian males: ED is a prevalent condition; the prevalence of ED increases with age and is strongly associated with comorbid conditions; and the majority of men have never sought treatment for their condition. This study highlights a substantial need for the evaluation and treatment of ED in Asian men.

  10. Fisica e fumetti: Paperone ed il deposito sotterraneo

    CERN Document Server

    Bagnoli, Franco

    2011-01-01

    I fumetti, come i film, spesso utilizzano idee scientifiche "fantasiose". Non ci riferiamo qui alla violazione implicita delle leggi della fisica, cosa permessa in un mondo di fantasia, quanto piuttosto all'uso di spiegazioni fisiche errate che vengono usate in buona fede perch\\'e a riflettono convinzioni molto diffuse, ma sbagliate, sull'interpretazione di fenomeni a partire dai principi fisici. D'altra parte questi errori possono servire a illustrare la corretta applicazione della fisica in una maniera molto pi\\`u accattivante rispetto alla modalit\\'a tradizionale di presentazione. Analizziamo qui l'avventura Paperone ed il deposito sotterraneo di Pezzin e Cavezzano. ----- Comics and cartoon movies sometimes exploit fictitious scientific ideas. It is often the case that these ideas, althought wrong, actually reflect the popular vision of some natural phenomenon. We do not refer here to the implicit violation of physical laws in fictions, a practice allowed by the underlining "poetic licence" of comics. Howe...

  11. EDS V25 containment vessel explosive qualification test report.

    Energy Technology Data Exchange (ETDEWEB)

    Rudolphi, John Joseph

    2012-04-01

    The V25 containment vessel was procured by the Project Manager, Non-Stockpile Chemical Materiel (PMNSCM) as a replacement vessel for use on the P2 Explosive Destruction Systems. It is the first EDS vessel to be fabricated under Code Case 2564 of the ASME Boiler and Pressure Vessel Code, which provides rules for the design of impulsively loaded vessels. The explosive rating for the vessel based on the Code Case is nine (9) pounds TNT-equivalent for up to 637 detonations. This limit is an increase from the 4.8 pounds TNT-equivalency rating for previous vessels. This report describes the explosive qualification tests that were performed in the vessel as part of the process for qualifying the vessel for explosive use. The tests consisted of a 11.25 pound TNT equivalent bare charge detonation followed by a 9 pound TNT equivalent detonation.

  12. Research on technology of laser cladding Ni/WC-Y2O3 on 35CrMo steel surface%35CrMo钢表面激光熔覆Ni/WC-Y2O3合金工艺研究

    Institute of Scientific and Technical Information of China (English)

    丁阳喜; 孙晓龙

    2011-01-01

    The influences of laser power, scanning speed and off-focus on the properties of layer cladding Ni/WC -Y2O3 on the surface of 35CrMo steel were studied. Choose the right levels to make the orthogonal experiment , then the laser cladding process parameters which adapt to produce the excellent hardness and surface wear properties of the cladding layer could be got. In addition, the influence of WC and Y2O3 to the microstructure properties of the cladding layer was also analyzed.%研究了35CrMo钢表面激光熔覆Ni/WC-Y2O3时激光功率、扫描速度和离焦量对熔覆层性能的影响,通过选择合适的水平进行正交试验,得到了熔覆层硬度和耐磨性能优良的较优工艺参数.此外,还分析了WC和Y2O3对熔覆层组织性能的影响.

  13. Influence of spraying powders on properties of cold-sprayed WC cermet coatings%粉末制备工艺对冷喷WC金属陶瓷涂层性能的影响

    Institute of Scientific and Technical Information of China (English)

    陈枭; 王洪涛; 纪岗昌; 白小波; 董增祥; 王芳

    2013-01-01

    采用包覆、机械混合与团聚烧结工艺制备了多尺度WC-17Ni和ZYT10001A(WC-17% Co),WCTN(WC-17% Co)金属陶瓷粉末.用3种粉末冷喷涂沉积涂层,运用扫描电镜分析了涂层的组织结构、X射线衍射表征粉末与涂层的物相结构,用压入法测定了涂层的显微硬度、弹性模量和断裂韧性.研究结果表明,3种粉末沉积的涂层均具呈现致密的组织结构,涂层中的相结构没有发生变化.3种涂层的显微硬度、弹性模量和断裂韧性分别在(650.8±40.4)~ (1350.0±115) HV0.3、(182.6±66.6) ~(309.9±52.9)GPa和(13.12±4.44)~ (24±1)MPa·m1/2之间变化,其中以ZYT10001A(WC-17% Co)涂层的硬度值最大及断裂韧性值最小.%WC-17Ni, ZYT10001A ( WC-17% Co) and WCTN ( WC-17% Co) powders fabricated by cladding, mechanical mixing, agglomerate-sintering method respectively were deposited on stainless steel substrate to obtain WC cermet coatings by cold spraying. Microstructure of the coatings was studied by scanning electron microscopy, phase composnent was investigated by means of X-ray diffraction, and the microhardness, elastic modulus and fracture toughness were measured by indentation method. The results show that the coatings depsited by using three kinds of powders exhibited dense microstructure. The phases of the feedstocks remained unchanged in the coatings. The microhardness, elastic modulus and fracture toughness of the coatings varied from (650.8±40.4) to (1350. 0 ± 115) HV0.3, (182. 6 ±66. 6) to (309. 9 ±52. 9) GPa and (13. 12+4.44) to (24±1) MPa-m1/2, respectively, and ZYT10001A( WC-17% Co) coating had the highest value of microhardness and the lowest value of fracture toughness in the three coatings.

  14. ED services: the impact of caring behaviors on patient loyalty.

    Science.gov (United States)

    Liu, Sandra S; Franz, David; Allen, Monette; Chang, En-Chung; Janowiak, Dana; Mayne, Patricia; White, Ruth

    2010-09-01

    This article describes an observational study of caring behaviors in the emergency departments of 4 Ascension Health hospitals and the impact of these behaviors on patient loyalty to the associated hospital. These hospitals were diverse in size and geography, representing 3 large urban community hospitals in metropolitan areas and 1 in a midsized city. Research assistants from Purdue University (West Lafayette, IN) conducted observations at the first study site and validated survey instruments. The Purdue research assistants trained contracted observers at the subsequent study sites. The research assistants conducted observational studies of caregivers in the emergency departments at 4 study sites using convenience sampling of patients. Caring behaviors were rated from 0 (did not occur) to 5 (high intensity). The observation included additional information, for example, caregiver roles, timing, and type of visit. Observed and unobserved patients completed exit surveys that recorded patient responses to the likelihood-to-recommend (loyalty) questions, patient perceptions of care, and demographic information. Common themes across all study sites emerged, including (1) the area that patients considered most important to an ED experience (prompt attention to their needs upon arrival to the emergency department); (2) the area that patients rated as least positive in their actual ED experience (prompt attention to their needs upon arrival to the emergency department); (3) caring behaviors that significantly affected patient loyalty (eg, making sure that the patient is aware of care-related details, working with a caring touch, and making the treatment procedure clearly understood by the patient); and (4) the impact of wait time to see a caregiver on patient loyalty. A number of correlations between caring behaviors and patient loyalty were statistically significant (P loyalty but that occurred least frequently. The study showed through factor analysis that some caring

  15. Functions of EDS1-like and PAD4 genes in grapevine defenses against powdery mildew.

    Science.gov (United States)

    Gao, Fei; Dai, Ru; Pike, Sharon M; Qiu, Wenping; Gassmann, Walter

    2014-11-01

    The molecular interactions between grapevine and the obligate biotrophic fungus Erysiphe necator are not understood in depth. One reason for this is the recalcitrance of grapevine to genetic modifications. Using defense-related Arabidopsis mutants that are susceptible to pathogens, we were able to analyze key components in grapevine defense responses. We have examined the functions of defense genes associated with the salicylic acid (SA) pathway, including ENHANCED DISEASE SUSCEPTIBILITY 1 (EDS1), EDS1-LIKE 2 (EDL2), EDL5 and PHYTOALEXIN DEFICIENT 4 (PAD4) of two grapevine species, Vitis vinifera cv. Cabernet Sauvignon, which is susceptible to E. necator, and V. aestivalis cv. Norton, which is resistant. Both VaEDS1 and VvEDS1 were previously found to functionally complement the Arabidopsis eds1-1 mutant. Here we show that the promoters of both VaEDS1 and VvEDS1 were induced by SA, indicating that the heightened defense of Norton is related to its high SA level. Other than Va/VvEDS1, only VaEDL2 complemented Arabidopsis eds1-1, whereas Va/VvPAD4 did not complement Arabidopsis pad4-1. Bimolecular fluorescence complementation results indicated that Vitis EDS1 and EDL2 proteins interact with Vitis PAD4 and AtPAD4, suggesting that Vitis EDS1/EDL2 forms a complex with PAD4 to confer resistance, as is known from Arabidopsis. However, Vitis EDL5 and PAD4 did not interact with Arabidopsis EDS1 or PAD4, correlating with their inability to function in Arabidopsis. Together, our study suggests a more complicated EDS1/PAD4 module in grapevine and provides insight into molecular mechanisms that determine disease resistance levels in Vitis species native to the North American continent.

  16. Estudio por emisión acústica del comportamiento a flexión de recubrimientos WC-Co obtenidos por plasma atmosférico

    Directory of Open Access Journals (Sweden)

    Segovia, F.

    2007-12-01

    Full Text Available Plasma sprayed cermet coatings WC-Co are used in a wide range of industrial applications, mainly due to their wear resistance even in corrosive environments. The objective of this work is to analyze mechanical response of hard metal coatings by means of three- and four-points bend tests applying acoustic emission technique to determine failure critical strength. It has been observed the effect of supported charge level in structural damage by means of optical microscopy and scanning electron microscopy. Acoustic emission has allowed us to relate damage level to stresses level and then to understand coatings failure mechanism.

    Los recubrimientos de cermet WC-Co proyectados por plasma se utilizan en un amplio rango de aplicaciones industriales, principalmente por su resistencia al desgaste, incluso en medio corrosivo. El objetivo de este trabajo es analizar la respuesta mecánica de los recubrimientos de metal duro mediante ensayos de flexión a 3 y 4 puntos aplicando el método de emisión acústica para determinar las tensiones críticas de fallo. Se ha observado el efecto del nivel de carga soportado en el dañado estructural mediante microscopia óptica y electrónica de barrido. La emisión acústica ha permitido relacionar el grado de dañado con el nivel de tensiones y, así, entender el mecanismo de fallo de los recubrimientos.

  17. Effect of Spray Particle Velocity on Cavitation Erosion Resistance Characteristics of HVOF and HVAF Processed 86WC-10Co4Cr Hydro Turbine Coatings

    Science.gov (United States)

    Kumar, R. K.; Kamaraj, M.; Seetharamu, S.; Pramod, T.; Sampathkumaran, P.

    2016-08-01

    The hydro plants utilizing silt-laden water for power generation suffer from severe metal wastage due to particle-induced erosion and cavitation. High-velocity oxy-fuel process (HVOF)-based coatings is widely applied to improve the erosion life. The process parameters such as particle velocity, size, powder feed rate, temperature, affect their mechanical properties. The high-velocity air fuel (HVAF) technology, with higher particle velocities and lower spray temperatures, gives dense and substantially nonoxidized coating. In the present study, the cavitation resistance of 86WC-10Co4Cr-type HVOF coating processed at 680 m/s spray particle velocity was compared with HVAF coatings made at 895, 960, and 1010 m/s. The properties such as porosity, hardness, indentation toughness, and cavitation resistance were investigated. The surface damage morphology has been analyzed in SEM. The cohesion between different layers has been examined qualitatively through scratch depth measurements across the cross section. The HVAF coatings have shown a lower porosity, higher hardness, and superior cavitation resistance. Delamination, extensive cracking of the matrix interface, and detachment of the WC grains were observed in HVOF coating. The rate of metal loss is low in HVAF coatings implying that process parameters play a vital role in achieving improved cavitation resistance.

  18. Wear Micro-Mechanisms of Composite WC-Co/Cr - NiCrFeBSiC Coatings. Part I: Dry Sliding

    Directory of Open Access Journals (Sweden)

    D. Kekes

    2014-12-01

    Full Text Available The influence of the cermet fraction in cermet/ metal composite coatings developed by High-Velocity Oxyfuel Flame (HVOF spraying on their tribological behaviour was studied. Five series of coatings, each one containing different proportion of cermet-metal components, prepared by premixing commercially available feedstocks of NiCrFeBSiC metallic and WC-Co/Cr cermet powders were deposited on AISI 304 stainless steel substrate. The microstructure of as-sprayed coatings was characterized by partial decomposition of the WC particles, lamellar morphology and micro-porosity among the solidified splats. Tribological behavior was studied under sliding friction conditions using a Si3N4 ball as counterbody and the friction coefficient and volume loss were determined as a function of the cermet fraction. Microscopic examinations of the wear tracks and relevant cross sections identified the wear mechanisms involved. Coatings containing only the metallic phase were worn out through a combination of ploughing, micro-cracking and splat exfoliation, whilst those containing only the cermet phase primarily by micro-cracking at the individual splat scale. The wear mechanisms of the composite coatings were strongly affected by their randomly stratified structure. In-depth cracks almost perpendicular to the coating/ substrate interface occurring at the wear track boundaries resulted in cermet trans-splat fracture.

  19. Mechanical property changes in HVOF sprayed nano-structured WC-17wt.%Ni(80/20)Cr coating with varying substrate roughness

    Science.gov (United States)

    Ben Mahmud, Tarek A.; Saha, Gobinda C.; Khan, Tahir I.

    2014-06-01

    Thermally sprayed coatings developed by use of high velocity oxy-fuel (HVOF) process are known for their superior wear characteristics. In many industrial applications, new parts as well as repaired and refurbished parts coated with WC-Co microstructured coatings have shown enhanced erosion-corrosion and abrasive resistant properties when compared with other surface modification technologies such as chrome replacement, fusion welding, and cladding. This research has been further directed towards the development of HVOF technique to deposit dense nanostructured ceramic-metallic composites. The mechanism of plastic deformation, which determines the strength and ductility of materials, in nanostructured materials are different, thereby leading to novel mechanical properties. Various parameters can influence these properties, but the substrate surface preparation by grit blasting before thermal spraying is one critical parameter. The grit blasting process generates a surface roughness, which ensures mechanical anchoring between the coating and the substrate surface. In this work, the sliding wear behavior and microhardness of WC-17wt.%Ni(80/20)Cr cermet coatings deposited onto carbon steel substrates are examined as a function of three different surface roughness values under different loads. The results show that as-prepared surface with different blasting profiles have a direct influence on the surface roughness and wear performance of the coatings. The sliding wear resistance of the coatings increased as the substrate surface roughness increased. The wear depth decreased with increasing surface roughness.

  20. Influence of Plasma Transferred Arc Process Parameters on Structure and Mechanical Properties of Wear Resistive NiCrBSi-WC/Co Coatings

    Directory of Open Access Journals (Sweden)

    Eitvydas GRUZDYS

    2011-07-01

    Full Text Available Self-fluxing NiCrBSi and related coatings received considerable interest due to their good wear as well as corrosion resistance at moderate and elevated temperatures. Hard tungsten carbide (WC particles can be included in NiCrBSi for further increase of the coating hardness and abrasive wear resistance. Flame spray technique is widely used for fabrication of NiCrBSi films. However, in such a case, subsequent remelting of the deposited coatings by flame, arc discharge or high power laser beam is necessary. In present study NiCrBSi-WC/Co coatings were formed using plasma transferred arc process. By adjusting plasma parameters, such as current, plasma gas flow, shielding gas flow, a number of coatings were formed on steel substrates. Structure of the coatings was investigated using X-ray diffractometry. Microstructure of cross-sectioned coatings was examined using scanning electron microscopy. Hardness of the coating was evaluated by means of the Vickers hardness tests. Wear tests were also performed on specimens to determine resistance to abrasive wear. Acquired results allowed estimating the influence of the deposition process parameters on structure and mechanical properties of the coatings.http://dx.doi.org/10.5755/j01.ms.17.2.482

  1. Effects of coating thickness and interfacial roughness on cracking and delamination strength of WC-Co coating measured by ring compression test

    Science.gov (United States)

    Kato, Masahiko; Nazul, Mahmoud; Itti, Takeshi; Akebono, Hiroyuki; Sugeta, Atsushi; Mitani, Eiji

    2014-08-01

    The effects of coating thickness and interfacial roughness on the interfacial fracture toughness of tungsten carbide-cobalt (WC-Co) coatings were evaluated using a ring compression test. WC-Co powder was sprayed on steel (JIS:SS400) rings by a high-velocity air- fuel method in coatings with various thicknesses and values of interfacial roughness. The ring compression test was carried out, and the cracking and delamination behavior of the coatings was observed using charge-coupled-device cameras. The results showed that cracking perpendicular to the loading direction occurred in the coatings during the ring compression test, and the cracking strength obtained from the ring compression test decreased slightly with increasing coating thickness, but was independent of the interfacial roughness. Upon further increase of the compression load, the coatings delaminated from the substrate. The interfacial fracture toughness calculated from the delamination of the coatings during the ring compression test decreased with increasing coating thickness and increased with increasing interfacial roughness.

  2. RT-PCR Analysis of ED-A,ED-B, and IIICS Fibronectin Domains: A New Screening Marker For Bladder Cancer

    Directory of Open Access Journals (Sweden)

    M Ahmadi Javid

    2004-12-01

    Full Text Available Background: Fibronectin seems to play a very important role in the progression and invasion of bladder cancer. EDA, EDB, and IIICS domains of fibronectin are not expressed in the adult persons but they’re expressed in different cancers. The aim of this study is to investigate the mRNA of fibronectin in transitional carcinoma cells (TCC of bladder to study these domains. Methods: A total of 20 patients with known bladder cancer were studied. Two of them excluded since their excised tissues were not enough for both the pathological examination and RNA study. Another 20 (control group were normal volunteers who needed bladder operations. The excised tissue was immediately transferred to RNAlater (Ambion,TX. RNA was extracted via RNAWIZ (Ambion, TX. cDNA was made via RevertAid First Strand cDNA Synthesis Kit (Fermentas. PCR of the cDNAs was performed using primers for EDA, EDB, and IIICS (Eurogentec,Belgium. Results: For the first time, we present the expression of the oncofetal fibronectin mRNA in the transitional cell carcinoma of bladder. The high grade muscle invasive (G3T2 tumor, expressed ED-A, ED-B, and IIICS. Expression of ED-A, ED-B, and IIICS was confirmed in the two patients with G3T1 TCC. The four patients with G2Ta and G3Ta expressed both ED-A and ED-B. The four patients with G1T1 tumor expressed ED-A only, similar to the nine patients with G1Ta tumor. None of the normal volunteers expressed the oncofetal extra domains. The sensitivity of ED-A positive fibronectin RNA for detecting TCC of any kind is 100%, and of ED-B was only 35%. The specificity of ED-B positive fibronectin RNA for the high grade TCC is 100%. Conclusion: ED-A, ED-B, and IIICS could be used as useful markers for the diagnosis and following up of bladder carcinoma. Keywords: Transitional Cell Carcinoma, bladder cancer, fibronectin, RT-PCR, oncofetal.

  3. Patient-Centered Care Transition for Patients Admitted through the ED: Improving Patient and Employee Experience

    Directory of Open Access Journals (Sweden)

    Andrea Algauer BSN, RN

    2015-05-01

    Full Text Available With increasing wait times in emergency departments (ED across America, there is a need to streamline the inpatient admission process in order to decrease wait times and more important, to increase patient and employee satisfaction. One inpatient unit at New York-Presbyterian Weill Cornell Medical Center initiated a program to help expedite the inpatient admission process from the ED. The goal of the ED Bridge program is to ease the patient's transition from the ED to an inpatient unit by visiting the patient in the ED and introducing and setting expectations for the inpatient environment (i.e. telemetry alarms, roommates, hourly comfort rounds. Along with improving the patient experience, this program intends to improve the collaboration between ED nurses and inpatient nurses. With the continued support of our nurse management, hospital administrators and most important, our staff, this concept is aimed to increase patient satisfaction scores and subsequently employee satisfaction.

  4. The NStED Periodogram Service and Interface for Public CoRoT Data

    CERN Document Server

    von Braun, K; Beekley, A; Berriman, G B; Bryden, G; Chan, B; Ciardi, D R; Good, J; Harbut, M; Kane, S R; Laity, A; Lau, C; Lynn, M; McElroy, D; Plavchan, P; Regelson, M; Rey, R; Ramirez, S V; Stauffer, J; Zhang, A

    2011-01-01

    As part of the NASA-CNES agreement, the NASA Star and Exoplanet Database (NStED) serves as the official US portal for the public CoRoT data products. NStED is a general purpose archive with the aim of providing support for NASA's planet finding and characterization goals. Consequently, the NASA Exoplanet Science Institute (NExScI) developed, and NStED adapted, a periodogram service for CoRoT data to determine periods of variability phenomena and create phased photometric light curves. Through the NStED periodogram interface, the user may choose three different period detection algorithms to use on any photometric time series product, or even upload and analyze their own data. Additionally, the NStED periodogram is remotely accessed by the CoRoT archive as part of its interface. NStED is available at {\\bf http://nsted.ipac.caltech.edu}.

  5. Effect of Layered Double Hydroxides on Ultraviolet Aging Resistance of SBS Modifi ed Bitumen Membrane

    Institute of Scientific and Technical Information of China (English)

    XU Song; YU Jianying; XUE Lihui; SUN Yubin; XIE Dong

    2015-01-01

    Layered double hydroxides (LDHs)/styrene-butadiene-styrene (SBS) copolymer modified bitumen was prepared by melt blending. The effect of LDHs on the ultraviolet (UV) aging behavior of SBS modifi ed bitumen was investigated. The changes of chemical structures of modifi ed bitumen before and after UV aging were characterized by Fourier transform infrared spectroscopy (FTIR). The results show that LDHs obviously reduce the variation of softening point and low temperaturefl exibility of SBS modifi ed bitumen under different UV radiation intensities, which indicates that the UV aging resistance performance of SBS modifi ed bitumen is improved effectively by LDHs. Compared with SBS modifi ed bitumen, the changes of carbonyl, sulfoxide and butadienyl of LDHs/SBS modified bitumen decrease significantly after UV aging according to FTIR analysis, demonstrating that the oxidation and degradation reactions of SBS modifi ed bitumen were restrained effectively by adding LDHs.

  6. SURFACE MODIFICATION OF WC-Ni CEMENTED CARBIDE FOR SEALS BY HIGH-INTENSITY PULSED ION BEAM IRRADIATION%强流脉冲离子束辐照WC-Ni硬质密封材料表面改性研究

    Institute of Scientific and Technical Information of China (English)

    张锋刚; 朱小鹏; 王明阳; 雷明凯

    2011-01-01

    The WC-Ni cemented carbide, as a promising seal component material in nuclear power plant, was treated by high-intensity pulsed ion beam (HIPIB) with ion energy of 300 keV, ion current density of 300 A/cm2, I.e., at a power density of 108 W/cm2 and at a pulse duration of 70 ns up to 10 shots. The phase composition, surface morphology and element distribution in the surface of WC-Ni cemented carbide before and after HIPIB irradiation were investigated by using XRD, SEM and EPMA, and its properties were characterized by microhardness measurement and block-on-ring wear testing. It is found that the phase transformation from hexagonal WC to cubic /3-Wci_x underwent in the irradiated surface layer, and the amount of /3-Wci_x phase increased with increasing shot number. The surface remelting and selective ablation of the nickel binder phase resulted in the formation of hilly topography with numerous protrusions on the irradiated surfaces, and the dimension of protrusions expanded under repetitive irradiation. As increasing the irradiation up to 10 shots, a network of hill-valleys was finally produced on the irradiated surfaces but the surface is smoothed and densified in a micro scale. A hardened depth of 160μm was obtained, which is attributable to the strong stress wave induced during the irradiation. As a result, the wear resistance of WC-Ni cemented carbides is considerably improved by a factor of 3 along with a 38% reduction in the friction coefficient after 10-shot irradiation.%利用离子能量为300 keV,束流密度为300 A/cm2,功率密度为108 W/cm2,脉冲宽度为70 ns的强流脉冲离子束(HIPIB)对用于核主泵轴密封的WC-Ni硬质合金材料进行了表面辐照处理,辐照次数分别为1,5,10次.利用XRD,SEM和EPMA研究了HIPIB辐照前后WC-Ni硬质合金表层相组成、表面形貌和元素分布的变化,借助显微硬度计和环-块式磨损仪测试了辐照前后硬质合金表层的性能.结果表明,HIPIB辐照硬质合金表层

  7. Are family physicians the answer to ED doctor shortage, or 'blasphemy'?

    Science.gov (United States)

    2011-01-01

    Some organizations maintain that family physicians have the skills and training necessary to practice in the ED and help combat the current physician shortage, while others maintain their training is inadequate. Here are some issues to take into consideration with such candidates: Have they obtained thorough experience the necessary skills to practice in the ED? Have they received a significant amount of clinical training in an ED? Has their training progress been monitored by a teaching attending?

  8. Effect of Mo{sub 2}C/(Mo{sub 2}C + WC) weight ratio on the microstructure and mechanical properties of Ti(C,N)-based cermet tool materials

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Qingzhong; Zhao, Jun, E-mail: zhaojun@sdu.edu.cn; Ai, Xing; Qin, Wenzhen; Wang, Dawei; Huang, Weimin

    2015-11-15

    To optimize the Mo{sub 2}C content in Ti(C,N)-based cermet tool materials used for cutting the high-strength steel of 42CrMo (AISI 4140/4142 steel), the cermets with different Mo{sub 2}C/(Mo{sub 2}C + WC) weight ratios were prepared. And the microstructure and mechanical properties of cermets were investigated by scanning electron microscope (SEM), X-ray diffraction (XRD) and measurements of transverse rupture strength (TRS), Vickers hardness (HV) and fracture toughness (K{sub IC}). The results indicate that the Mo{sub 2}C/(Mo{sub 2}C + WC) ratios have great influences on the microstructure features and mechanical properties of Ti(C,N)-based cermets. When the Mo{sub 2}C/(Mo{sub 2}C + WC) ratio increases, the Ti(C,N) grains become finer with smaller black cores surrounded by thinner rims, and the structure of cermets tends to be more compact with smaller binder mean free path. Owing to the medium grains and moderate rims, the cermets with a Mo{sub 2}C/(Mo{sub 2}C + WC) ratio of 0.4 exhibit better mechanical properties, and can be chosen as the tool material for machining 42CrMo steel due to the lower Mo content. - Highlights: • Mo{sub 2}C/(Mo{sub 2}C + WC) ratios affect microstructure and mechanical properties of cermets. • Grains become fine and structure of cermets tends to be compact with raised Mo{sub 2}C. • The cermets with a Mo{sub 2}C/(Mo{sub 2}C + WC) ratio of 0.4 can be used to machine 42CrMo steel.

  9. Optimal cut points of waist circumference (WC) and visceral fat area (VFA) predicting for metabolic syndrome (MetS) in elderly population in the Korean Longitudinal Study on Health and Aging (KLoSHA).

    Science.gov (United States)

    Lim, Soo; Kim, Jung Hee; Yoon, Ji Won; Kang, Seon Mee; Choi, Sung Hee; Park, Young Joo; Kim, Ki Woong; Cho, Nam Han; Shin, Hayley; Park, Kyong Soo; Jang, Hak Chul

    2012-01-01

    Optimal cut points of central obesity identifying subjects at risk for MetS were proposed ethnic-specifically, but have not been established yet. Of particular interest are the values for elderly persons, which have not been identified previously. We investigated the appropriate cut points of WC and VFA for elderly in a community-based cohort in Korea. We recruited 294 men and 313 women aged 65 or over who participated in the KLoSHA. A receiver operating characteristic (ROC) curve analysis was used to estimate the optimal cut points of WC and VFA indicative of MetS. The optimal cut points for predicting MetS were 87 cm for WC, 140 cm(2) for VFA in men, and 85 cm for WC, 100 cm(2) for VFA in women with the Youden index. Similar cut points were obtained with the closest-to-(0, 1) criterion except for VFA in men, which was 122 cm(2). When adjusted for age, exercise, smoking, and alcohol consumption, men with ≥122 cm(2) and women with ≥100 cm(2) of VFA had a higher risk of MetS than subjects with lower values. The cut points of VFA and WC at risk for MetS were higher in men than women. In this community-based elderly cohort, the optimal cut points of WC at risk for MetS were lower than the Western criteria. Compared with the cut points in middle-aged Koreans, the cut points for elderly were lower in men and similar in women.

  10. Spazio, movimento, prospettiva ed empatia: un prototipo di videogame didattico

    Directory of Open Access Journals (Sweden)

    Pio Alfredo Di Tore

    2014-09-01

    Full Text Available Questo lavoro presenta la cornice teorica che sta alla base della progettazione di un videogame didattico pensato per valutare le abilità di perspective taking (capacità di adottare la prospettiva altrui e di mental rotation (rotazione mentale dei giocatori. Lo studio mira a rilevare come tali abilità siano coinvolte nella relazione empatica e a verificarne le implicazioni in campo educativo. Il lavoro adotta la definizione di empatia riconducibile ad Alain Berthoz ed alla teoria spaziale dell’empatia qui presentata con i relativi sistemi di riferimento spaziale. È inoltre fornita una rapida revisione della letteratura sulla rappresentazione dello spazio nel bambino e sulla rappresentazione dello spazio nel gioco (su base visiva. Infine, il lavoro descrive il prototipo di gioco – realizzato presso l’Università di Salerno – in cui il giocatore si trova alle prese con tre differenti compiti di cui due progettati per misurare le abilità di perspective taking mentre il terzo è calibrato sulle abilità di mental rotation.

  11. Etica ed evoluzionismo: la proposta di Marc Hauser

    Directory of Open Access Journals (Sweden)

    Irene Pilloni

    2013-11-01

    Full Text Available Le recenti scoperte nell’ambito della psicologia evoluzionistica potrebbero offrire una risposta al dibattito sull’origine evoluzionistica della facoltà morale dell’Homo sapiens. In passato, il tentativo di spiegare il comportamento morale a partire dalla teoria dell’evoluzione è stato intrapreso dal padre fondatore dell’evoluzionismo Charles Darwin, successivamente da T.H. Huxley e da H. Spencer e infine dal sociobiologo E. Wilson a metà degli anni ‘70 del Novecento. Oggi questa impresa è stata ereditata dallo psicologo evoluzionista Marc Hauser, le cui indagini prendono avvio da un’analogia tra facoltà morale e facoltà linguistica. Questa analogia gli consente di affermare che la pluralità di codici morali adottati dagli uomini nelle differenti culture dipende da un numero limitato di principi morali, nello stesso modo in cui la varietà di lingue con cui gli uomini si esprimono, dipende da un numero limitato di principi linguistici universali. Dunque, sembrerebbe che l’evoluzione biologica abbia plasmato dei principi morali universali e uniformi che si presentano costanti in tutti gli uomini a prescindere dalla loro appartenenza culturale. Come vadano intesi i principi morali universali e quale rapporto intercorre tra di essi e i vari codici morali sarà l’argomento di questo saggio, il quale tenterà di analizzare la proposta di Marc Hauser all’interno della cornice dei rapporti tra etica ed evoluzionismo.

  12. Interdisciplinary mistrust, communication breakdowns cited in survey of ED handoffs.

    Science.gov (United States)

    2015-11-01

    Both emergency and inpatient physicians agree that miscommunication during interunit handoffs can compromise patient care and that sequential handoffs are particularly problematic, according to a new study conducted at the University of Nebraska Medical Center (UNMC) in Omaha, NE. The study highlights physician survey data showing that there is mistrust between inpatient and emergency physicians, and that which provider is responsible for patient care can be unclear when a verbal handoff is made. To make improvements, UNMC has been piloting a tool aimed at standardizing verbal and written handoff communications. Nearly a third of all the participating physicians surveyed reported having handoff-related adverse events, and most put the blame on ineffective communication. Ninety-four percent of emergency physicians surveyed indicated that they had to defend their clinical decisions at least some of the time. The admitting physicians largely validated this concern, with more than 25% noting that they usually disagree with decisions made in the ED. Using the situation, background, assessment, recommendation (SBAR) form of communication as a starting point, an intervention tool aims to streamline handoff communications, both verbally and in the electronic medical record.

  13. Book Review: Digital Forensic Evidence Examination (2nd ed.

    Directory of Open Access Journals (Sweden)

    Gary Kessler

    2010-06-01

    Full Text Available Cohen, F. (2010. Digital Forensic Evidence Examination (2nd ed.. Livermore, CA: ASP Press. 452 pages, ISBN: 978-1-878109-45-3, US$79.Reviewed by Gary C. Kessler, Gary Kessler Associates & Edith Cowan University (gck@garykessler.netOn the day that I sat down to start to write this review, the following e-mailcame across on one of my lists:Person A and Person B write back and forth and create an email thread. Person A then forwards the email to Person C, but changes some wording in the email exchange between A & B. What is the easiest way (and is it even possible to find out when that earlier email message was altered before sent to Person C?Before you try to answer these questions, read Fred Cohen's Digital Forensic Evidence Examination. His book won't actually tell you how to answer these questions but it will help you understand the difficulty in even trying to answer them with any level of certainty.(see PDF for full review

  14. Hearing of Mr. Francois Roussely, President of EdF; Audition de M. Francois Roussely, President d'EdF

    Energy Technology Data Exchange (ETDEWEB)

    Roussely, F. [Electricite de France (EDF), 75 - Paris (France)

    2005-07-01

    This document is the proceedings of the hearing of F. Roussely, President of Electricite de France (EdF), at the commission of economic affairs of the French house of commons, about the advisability of the construction of the EPR (European pressurized reactor) demonstration plant and about its possible financing by EdF. In a first part, F. Roussely recalls the European context of deregulation of energy markets and its impact of the French electric power industry (opening of the French market, industrial and social actions of EdF, need of a new generation of nuclear reactor, preservation of EdF's energy mix, warranty of public utility, un-bundling between energy trade and distribution, EdF's turnover and profitability, EdF's foreign daughter companies). In a second part, F. Roussely answers a series of questions asked by the different members of the commission concerning the different points presented in the first part. (J.S.)

  15. The utility of transvaginal ultrasound in the ED evaluation of complications of first trimester pregnancy.

    Science.gov (United States)

    Panebianco, Nova L; Shofer, Frances; Fields, J Matthew; Anderson, Kenton; Mangili, Alessandro; Matsuura, Asako C; Dean, Anthony J

    2015-06-01

    For patients with early intrauterine pregnancy (IUP), the sonographic signs of the gestation may be below the resolution of transabdominal ultrasound (TAU); however, it may be identified by transvaginal ultrasound (TVU). We sought to determine how often TVU performed in the emergency department (ED) reveals a viable IUP after a nondiagnostic ED TAU and the impact of ED TVU on patient length of stay (LOS). This was a retrospective cohort study of women presenting to our ED with complications of early pregnancy from January 1, 2007 to February 28, 2009 in a single urban adult ED. Abstractors recorded clinical and imaging data in a database. Patient imaging modality and results were recorded and compared with respect to ultrasound (US) findings and LOS. Of 2429 subjects identified, 795 required TVU as part of their care. Emergency department TVU was performed in 528 patients, and 267 went to radiology (RAD). Emergency department TVU identified a viable IUP in 261 patients (49.6%). Patients having initial ED US had shorter LOS than patients with initial RAD US (median 4.0 vs 6.0 hours; P < .001). Emergency department LOS was shorter for women who had ED TVU performed compared with those sent for RAD TVU regardless of the findings of the US (median 4.9 vs 6.7 hours; P < .001). There was no increased LOS for patients who needed further RAD US after an indeterminate ED TVU (7.0 vs 7.1 hours; P = .43). There was no difference in LOS for those who had a viable IUP confirmed on ED TAU vs ED (median 3.1 vs 3.2 hours, respectively; P < .32). When an ED TVU was performed, a viable IUP was detected 49.6% of the time. Emergency department LOS was significantly shorter for women who received ED TVU after indeterminate ED TAU compared with those sent to RAD for TVU, with more marked time savings among those with live IUP diagnosed on ED TVU. For patients who do not receive a definitive diagnosis of IUP on ED TVU, this approach does not result in increased LOS. Copyright © 2015

  16. Book Review: John M. Hobson and Leonard Seabrooke (2007) (eds) Everyday Politics of the World Economy

    DEFF Research Database (Denmark)

    Strange, Michael Stewart

    2009-01-01

    Book Review: John M. Hobson and Leonard Seabrooke (2007) (eds) Everyday Politics of the World Economy (Cambridge: Cambridge University Press), 254pp. Udgivelsesdato: 2009......Book Review: John M. Hobson and Leonard Seabrooke (2007) (eds) Everyday Politics of the World Economy (Cambridge: Cambridge University Press), 254pp. Udgivelsesdato: 2009...

  17. Multiple Intelligence and Digital Learning Awareness of Prospective B.Ed Teachers

    Science.gov (United States)

    Gracious, F. L. Antony; Shyla, F. L. Jasmine Anne

    2012-01-01

    The present study Multiple Intelligence and Digital Learning Awareness of prospective B.Ed teachers was probed to find the relationship between Multiple Intelligence and Digital Learning Awareness of Prospective B.Ed Teachers. Data for the study were collected using self made Multiple Intelligence Inventory and Digital Learning Awareness Scale.…

  18. A Review of "Older, Wiser, Sexually Smarter: 30 Sex Ed Lessons for Adults Only"

    Science.gov (United States)

    Garrity, Joan Mogul

    2010-01-01

    While virtually all sex ed curricula are designed to be used with children, teens and young adults, "Older, Wiser, Sexually Smarter: 30 Sex Ed Lessons for Adults Only" ([C] 2009, Planned Parenthood of Greater Northern New Jersey) offers lessons to help participants fully embrace the possibility of sexual pleasure and intimacy from mid-life through…

  19. MobilED – a mobile tools and services platform for formal and informal learning

    CSIR Research Space (South Africa)

    Ford, M

    2006-10-01

    Full Text Available The MobilED initiative is aimed at designing teaching and learning environments that are meaningfully enhanced with mobile technologies and services. The MobilED deliverables are to develop a set of scenarios and guidelines of how mobile...

  20. "What about Bilingualism?" A Critical Reflection on the edTPA with Teachers of Emergent Bilinguals

    Science.gov (United States)

    Kleyn, Tatyana; López, Dina; Makar, Carmina

    2015-01-01

    Amidst the debates surrounding teacher quality and preparation programs, the edTPA (education Teaching Performance Assessment) has emerged to assess future teachers through a portfolio-based certification process. This study offers the perspective of three faculty members who participated in an experimental configuration of edTPA implementation…