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Sample records for accessible toilets wc

  1. MedlinePlus: Toilet Training

    MedlinePlus

    ... to Use the Toilet (Zero to Three) Toilet Teaching Your Child (Nemours Foundation) Toilet Training Your Child (American Academy of Family Physicians) Also in Spanish Related Issues Cognitive and Verbal Skills Needed for ...

  2. Toilet Training Carl.

    ERIC Educational Resources Information Center

    Dunklee, Nancy R.

    1989-01-01

    The process of toilet training a boy with Rubinstein-Taybi Syndrome is addressed. Emphasized are the joint effort of the teacher and parents, the frustration at the seeming lack of progress, the use of rewards and "positive practices," and the ultimate success of the boy's toilet training program. (JDD)

  3. Aerosol Generation by Modern Flush Toilets

    PubMed Central

    Johnson, David; Lynch, Robert; Marshall, Charles; Mead, Kenneth; Hirst, Deborah

    2015-01-01

    A microbe-contaminated toilet will produce bioaerosols when flushed. We assessed toilet plume aerosol from high efficiency (HET), pressure-assisted high efficiency (PAT), and flushometer (FOM) toilets with similar bowl water and flush volumes. Total and droplet nuclei “bioaerosols” were assessed. Monodisperse 0.25–1.9-μm fluorescent microspheres served as microbe surrogates in separate trials in a mockup 5 m3 water closet (WC). Bowl water seeding was approximately 1012 particles/mL. Droplet nuclei were sampled onto 0.2-μm pore size mixed cellulose ester filters beginning 15 min after the flush using open-face cassettes mounted on the WC walls. Pre- and postflush bowl water concentrations were measured. Filter particle counts were analyzed via fluorescent microscopy. Bowl headspace droplet count size distributions were bimodal and similar for all toilet types and flush conditions, with 95% of droplets <2 μm diameter and >99% <5 μm. Up to 145,000 droplets were produced per flush, with the high-energy flushometer producing over three times as many as the lower energy PAT and over 12 times as many as the lowest energy HET despite similar flush volumes. The mean numbers of fluorescent droplet nuclei particles aerosolized and remaining airborne also increased with flush energy. Fluorescent droplet nuclei per flush decreased with increasing particle size. These findings suggest two concurrent aerosolization mechanisms—splashing for large droplets and bubble bursting for the fine droplets that form droplet nuclei. PMID:26635429

  4. Creating a Toilet Training Plan

    MedlinePlus

    ... Size Email Print Share Creating a Toilet Training Plan Page Content Article Body These are the tools ... will need to create your own toilet-training plan and implement it at the best time for ...

  5. "Toilet cake" encephalopathy.

    PubMed

    Zhang, Zhentao; Moreno, Alejandro

    2014-01-01

    Paradichlorobenzene (PDB) is an aromatic compound found in several household insect repellents and deodorizers. Paradichlorobenzene may cause dependence and damage when inhaled or ingested. Prior cases of PDB neurotoxicity involved ingestion or inhalation of mothballs or occupational exposure. We report the first case of PDB neurotoxicity from chronic toilet bowl deodorizers ("toilet cake") sniffing. A 19-year-old woman, 4 weeks postpartum, presented with gradual mental status deterioration, lethargy, and general weakness for 2 weeks. On physical examination, the patient was found to have a strong odor of deodorizer and diffuse hyperpigmented skin lesions, with scratch marks in neck, axillae, trunk, and 4 limbs. She was alert but unable to communicate or follow commands. Ataxia, hyporeflexia, cogwheel rigidity, and decreased muscle tone were also noted. Laboratory tests revealed only normocytic anemia. A brain magnetic resonance imaging scan showed enhancement within the splenium of the corpus callosum. Postpartum depression, psychosis, and panhypopituitarism were excluded. Family members reported on further questioning that the patient was a habitual "toilet cake" sniffer for an unknown period. A urine test for 2,5-dichlorophenol (a PDB metabolite) level was 620 mg/L (3100 times higher than the average concentration with household exposure). Her clinical condition and body odor remained unchanged during the 30-day hospitalization and the skin findings improved. PMID:25187976

  6. Toilet Training the Retarded Child.

    ERIC Educational Resources Information Center

    Schwartz, Jeffrey K.

    The booklet offers guidelines in both Spanish and English to parents who are toilet training a mentally retarded child. The toilet training process is broken down into tasks that the child must learn, and the importance of positive reinforcement for each successfully accomplished task is emphasized. It is recommended that parents keep charts…

  7. [Toilet of chronic wound].

    PubMed

    Strok, Nevenka; Huljev, Dubravko

    2013-10-01

    Chronic wound toilet, with appropriate care of the surrounding skin, is one of the basic steps that must be performed in the treatment of patients with chronic wound. On wound cleaning and bandaging, it is of utmost importance to choose an appropriate technique of cleansing, select an appropriate solution for leaching and choose an appropriate wound dressing. In this way, the wound is protected from dirt from the environment and microorganisms, while protecting the surrounding tissue from the wound exudate, providing optimal conditions for better and faster wound healing and contributing to improved patient quality of life. The frequency of dressing change is individual and must be tailored to each patient in correlation with the psychosocial status of the patient, the type of the wound, the amount and type of wound exudate, as well as what is to be put on the wound. One of the most important elements in wound toilet is appropriate care for the surrounding skin. Basic guidelines for skin care must meet three basic criteria: adequate washing and cleansing of the skin, maintain the physiological balance of the skin and protect the skin from external damage. PMID:24371977

  8. The toilet tripod: understanding successful sanitation in rural India.

    PubMed

    O'Reilly, Kathleen; Louis, Elizabeth

    2014-09-01

    Building toilets and getting people to use them is critical for public health. We deployed a political ecology approach specifically to identify the multi-scalar political, economic, and environmental factors influencing toilet adoption in rural India. The research used ethnographic and technical methods in rural villages of West Bengal and Himachal Pradesh over the period September 2012 to May 2013. The elements of successful sanitation adoption depended on three factors (i.e., toilet tripod): (1) multi-scalar political will on the part of both government and NGOs over the long term; (2) proximate social pressure, i.e., person-to-person contact between rural inhabitants and toilets; (3) political ecology, i.e., assured access to water, compatible soil type, and changing land use. This research contributes to studies of sustainable development and global public health by developing a theory and framework for successful sanitation. PMID:24954614

  9. Automatic toilet seat lowering apparatus

    DOEpatents

    Guerty, Harold G.

    1994-09-06

    A toilet seat lowering apparatus includes a housing defining an internal cavity for receiving water from the water supply line to the toilet holding tank. A descent delay assembly of the apparatus can include a stationary dam member and a rotating dam member for dividing the internal cavity into an inlet chamber and an outlet chamber and controlling the intake and evacuation of water in a delayed fashion. A descent initiator is activated when the internal cavity is filled with pressurized water and automatically begins the lowering of the toilet seat from its upright position, which lowering is also controlled by the descent delay assembly. In an alternative embodiment, the descent initiator and the descent delay assembly can be combined in a piston linked to the rotating dam member and provided with a water channel for creating a resisting pressure to the advancing piston and thereby slowing the associated descent of the toilet seat. A toilet seat lowering apparatus includes a housing defining an internal cavity for receiving water from the water supply line to the toilet holding tank. A descent delay assembly of the apparatus can include a stationary dam member and a rotating dam member for dividing the internal cavity into an inlet chamber and an outlet chamber and controlling the intake and evacuation of water in a delayed fashion. A descent initiator is activated when the internal cavity is filled with pressurized water and automatically begins the lowering of the toilet seat from its upright position, which lowering is also controlled by the descent delay assembly. In an alternative embodiment, the descent initiator and the descent delay assembly can be combined in a piston linked to the rotating dam member and provided with a water channel for creating a resisting pressure to the advancing piston and thereby slowing the associated descent of the toilet seat.

  10. Reducing Sexual Violence by Increasing the Supply of Toilets in Khayelitsha, South Africa: A Mathematical Model

    PubMed Central

    Gonsalves, Gregg S.; Kaplan, Edward H.; Paltiel, A. David

    2015-01-01

    Background Sexual violence is a major public health issue, affecting 35% of women worldwide. Major risk factors for sexual assault include inadequate indoor sanitation and the need to travel to outdoor toilet facilities. We estimated how increasing the number of toilets in an urban township (Khayelitsha, South Africa) might reduce both economic costs and the incidence and social burden of sexual assault. Methods We developed a mathematical model that links risk of sexual assault to the number of sanitation facilities and the time a woman must spend walking to a toilet. We defined a composite societal cost function, comprising both the burden of sexual assault and the costs of installing and maintaining public chemical toilets. By expressing total social costs as a function of the number of available toilets, we were able to identify an optimal (i.e., cost-minimizing) social investment in toilet facilities. Findings There are currently an estimated 5600 toilets in Khayelitsha. This results in 635 sexual assaults and US$40 million in combined social costs each year. Increasing the number of toilets to 11300 would minimize total costs ($35 million) and reduce sexual assaults to 446. Higher toilet installation and maintenance costs would be more than offset by lower sexual assault costs. Probabilistic sensitivity analysis shows that the optimal number of toilets exceeds the original allocation of toilets in the township in over 80% of the 5000 iterations of the model. Interpretation Improving access to sanitation facilities in urban settlements will simultaneously reduce the incidence of sexual assaults and overall cost to society. Since our analysis ignores the many additional health benefits of improving sanitation in resource-constrained urban areas (e.g., potential reductions in waterborne infectious diseases), the optimal number of toilets identified here should be interpreted as conservative. PMID:25923105

  11. Toilet Training Problems Could Be Physical

    MedlinePlus

    ... Español Text Size Email Print Share Toilet Training Problems Could Be Physical Page Content Article Body Many ... to young children’s toilet use result from physical problems that can be easily identified and resolved by ...

  12. Characteristics of Individuals with Toileting Problems and Intellectual Disability Using the "Profile of Toileting Issues" ("POTI")

    ERIC Educational Resources Information Center

    Matson, Johnny L.; Horovitz, Max; Sipes, Megan

    2011-01-01

    The prevalence of toileting problems was assessed in 153 adults with intellectual disability (ID) using the "Profile of Toileting Issues" ("POTI") and comparisons were made based on various demographic variables. The most frequently endorsed problems were "has toileting accidents during the day," "has toileting accidents during the night," "has…

  13. 30 CFR 57.20008 - Toilet facilities.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Toilet facilities. 57.20008 Section 57.20008 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-UNDERGROUND METAL AND NONMETAL MINES Miscellaneous § 57.20008 Toilet facilities. (a) Toilet...

  14. 30 CFR 57.20008 - Toilet facilities.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Toilet facilities. 57.20008 Section 57.20008 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-UNDERGROUND METAL AND NONMETAL MINES Miscellaneous § 57.20008 Toilet facilities. (a) Toilet...

  15. 30 CFR 56.20008 - Toilet facilities.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Toilet facilities. 56.20008 Section 56.20008 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-SURFACE METAL AND NONMETAL MINES Miscellaneous § 56.20008 Toilet facilities. (a) Toilet facilities...

  16. 30 CFR 56.20008 - Toilet facilities.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Toilet facilities. 56.20008 Section 56.20008 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-SURFACE METAL AND NONMETAL MINES Miscellaneous § 56.20008 Toilet facilities. (a) Toilet facilities...

  17. 49 CFR 228.317 - Toilets.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... Health Requirements for Camp Cars Provided by Railroads as Sleeping Quarters § 228.317 Toilets. (a... disposal method must not endanger the health of occupants. (3) For toilet facilities connected to a holding... drains from a camp car toilet facility must be connected to a public sewer where available and...

  18. 20 CFR 654.411 - Toilets.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... EMPLOYMENT SERVICE SYSTEM Housing for Agricultural Workers Housing Standards § 654.411 Toilets. (a) Toilets shall be constructed, located and maintained so as to prevent any nuisance or public health hazard. (b... 20 Employees' Benefits 3 2012-04-01 2012-04-01 false Toilets. 654.411 Section 654.411...

  19. 20 CFR 654.411 - Toilets.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... EMPLOYMENT SERVICE SYSTEM Housing for Agricultural Workers Housing Standards § 654.411 Toilets. (a) Toilets shall be constructed, located and maintained so as to prevent any nuisance or public health hazard. (b... 20 Employees' Benefits 3 2013-04-01 2013-04-01 false Toilets. 654.411 Section 654.411...

  20. 49 CFR 228.317 - Toilets.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... Health Requirements for Camp Cars Provided by Railroads as Sleeping Quarters § 228.317 Toilets. (a... disposal method must not endanger the health of occupants. (3) For toilet facilities connected to a holding... drains from a camp car toilet facility must be connected to a public sewer where available and...

  1. 49 CFR 228.317 - Toilets.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... Health Requirements for Camp Cars Provided by Railroads as Sleeping Quarters § 228.317 Toilets. (a... disposal method must not endanger the health of occupants. (3) For toilet facilities connected to a holding... drains from a camp car toilet facility must be connected to a public sewer where available and...

  2. 20 CFR 654.411 - Toilets.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... EMPLOYMENT SERVICE SYSTEM Housing for Agricultural Workers Housing Standards § 654.411 Toilets. (a) Toilets shall be constructed, located and maintained so as to prevent any nuisance or public health hazard. (b... 20 Employees' Benefits 3 2014-04-01 2014-04-01 false Toilets. 654.411 Section 654.411...

  3. Time to Terminate Toilet Papering

    ERIC Educational Resources Information Center

    Moscinski, David

    2008-01-01

    Each September in Wisconsin students return to school, football games draw enthusiastic crowds, and homecoming week is celebrated. Trees lose their leaves only to be re-adorned in white in that generation bridging tradition known as toilet papering. Community residents have differing opinions on "tp"ing, in large part determined by whether they…

  4. Thermoelectric energy harvesting for a solid waste processing toilet

    NASA Astrophysics Data System (ADS)

    Stokes, C. David; Baldasaro, Nicholas G.; Bulman, Gary E.; Stoner, Brian R.

    2014-06-01

    Over 2.5 billion people do not have access to safe and effective sanitation. Without a sanitary sewer infrastructure, self-contained modular systems can provide solutions for these people in the developing world and remote areas. Our team is building a better toilet that processes human waste into burnable fuel and disinfects the liquid waste. The toilet employs energy harvesting to produce electricity and does not require external electrical power or consumable materials. RTI has partnered with Colorado State University, Duke University, and Roca Sanitario under a Bill and Melinda Gates Foundation Reinvent the Toilet Challenge (RTTC) grant to develop an advanced stand-alone, self-sufficient toilet to effectively process solid and liquid waste. The system operates through the following steps: 1) Solid-liquid separation, 2) Solid waste drying and sizing, 3) Solid waste combustion, and 4) Liquid waste disinfection. Thermoelectric energy harvesting is a key component to the system and provides the electric power for autonomous operation. A portion of the exhaust heat is captured through finned heat-sinks and converted to electricity by thermoelectric (TE) devices to provide power for the electrochemical treatment of the liquid waste, pumps, blowers, combustion ignition, and controls.

  5. 30 CFR 71.501 - Sanitary toilet facilities; maintenance.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Sanitary toilet facilities; maintenance. 71.501... COAL MINES Sanitary Toilet Facilities at Surface Worksites of Surface Coal Mines § 71.501 Sanitary toilet facilities; maintenance. Sanitary toilets provided in accordance with the provisions of §...

  6. Toilet Habits: Suggestions for Training a Child Who Is Blind.

    ERIC Educational Resources Information Center

    Moor, Pauline M.

    Intended for parents, the pamphlet provides suggestions for toilet training a blind child. Among the 12 tips presented are to establish a regular and convenient toileting schedule, provide a comfortable toilet arrangement, and give the child something to play with. Common problems in toilet training blind children are reported as fear of sitting…

  7. Effectiveness of the Modified Intensive Toilet Training Method on Teaching Toilet Skills to Children with Autism

    ERIC Educational Resources Information Center

    Ardiç, Avsar; Cavkaytar, Atilla

    2014-01-01

    The purpose of this study was to determine effectiveness of a modified version of Azrin and Foxx's (1971) intensive toilet training method on teaching of toilet skills to children with autism. This method consists of administering extra fluids and a time schedule, but does not use overcorrection procedures. Implementation requires a study of…

  8. Multilayer diamond coated WC tools

    SciTech Connect

    Fan, W.D.; Jagannaham, K.; Narayan, J.

    1995-12-31

    To increase adhesion of diamond coatings, a multilayer structure was developed. The multilayer diamond coating consisted of a first discontinuous diamond layer, an interposing layer, and a top continuous diamond layer. The diamond layer was grown on WC substrates by hot filament chemical vapor deposition and the interposing layer was grown by pulsed laser deposition. Machining tests were used to characterize adhesion properties of the multilayer diamond coatings on WC(Co) substrates. Results indicate that diamond coatings exhibit good adhesion on the WC tool substrates. The wear resistance of the WC tool is improved significantly by the diamond coatings.

  9. Sampling and analysis of the inactive waste tanks TH-2, WC-1, and WC-15

    SciTech Connect

    Autrey, J.W.; Keller, J.M.; Griest, W.H.; Botts, J.L.; Schenley, R.L.; Sipe, M.A.

    1992-02-01

    Thirty-eight inactive liquid low-level radioactive waste tanks are currently managed by the Environmental Restoration Program of Oak Ridge National Laboratory. The contents of these tanks are to be characterized in preparation for future corrective actions and remediation activities as part of compliance with the pending Federal Facility Agreement for the Oak Ridge Reservation. Twenty-nine of these tanks were sampled and analyzed in 1989. Three of the tanks (TH-2, WC-1, and WC-15) were not accessible from the surface and thus were not sampled until 1990. This report presents the sampling and analytical results of that campaign. All three tanks in this report had negligible regulatory organic compounds in the samples that were collected. There were no US Environmental Protection Agency (EPA) Target Compound List (TCL) constituents for volatile organics detected in any of the aqueous samples. The only semivolatile organics detected were 2-chlorophenol (52 {mu}g/L) in tank TH-2 and dichloroethane (14--15 {mu}g/L) and diethyl either (15--17 {mu}g/L) in tank WC-15. A thin oil layer was discovered floating on top of the aqueous contents in tank WC-15. The analysis of the oil layer detected no volatile organics and showed only one EPA TCL constituent, di-n-butylphthalate, at 1900 {mu}g/L. Low levels of Resource Conservation and Recovery Act (RCRA) metals were observed in the samples from tank TH-2, but only the mercury level exceeded the RCRA limit. Samples from tank WC-1 had elevated levels of the RCRA metals barium, chromium, and lead. There were also finely suspended particles in one of the samples from tank WC-1, which was filtered and analyzed separately. This solid fines have levels of transuranium elements {sup 238}Pu and {sup 241}Am high enough to classified as transuranic waste.

  10. 21 CFR 211.52 - Washing and toilet facilities.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... § 211.52 Washing and toilet facilities. Adequate washing facilities shall be provided, including hot and cold water, soap or detergent, air driers or single-service towels, and clean toilet facilities...

  11. 21 CFR 211.52 - Washing and toilet facilities.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... § 211.52 Washing and toilet facilities. Adequate washing facilities shall be provided, including hot and cold water, soap or detergent, air driers or single-service towels, and clean toilet facilities...

  12. 46 CFR 92.20-25 - Washrooms and toilet rooms.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...) There must be provided at least 1 toilet, 1 washbasin, and 1 shower or bathtub for each 8 members or... with adequate plumbing, including hot and cold running water. All toilets must be installed...

  13. 46 CFR 190.20-25 - Washrooms and toilet rooms.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... and toilet rooms. (a) There must be provided at least 1 toilet, 1 washbasin, and 1 shower or bathtub..., showers, and bathtubs must be equipped with adequate plumbing, including hot and cold running water....

  14. 46 CFR 190.20-25 - Washrooms and toilet rooms.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... and toilet rooms. (a) There must be provided at least 1 toilet, 1 washbasin, and 1 shower or bathtub..., showers, and bathtubs must be equipped with adequate plumbing, including hot and cold running water....

  15. 46 CFR 72.20-25 - Washrooms and toilet rooms.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... least 1 toilet, 1 washbasin, and 1 shower or bathtub for each 8 members or portion thereof in the crew... adequate plumbing, including hot and cold running water. All toilets must be installed with...

  16. 46 CFR 168.15-30 - Toilet rooms.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 false Toilet rooms. 168.15-30 Section 168.15-30 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) NAUTICAL SCHOOLS CIVILIAN NAUTICAL SCHOOL VESSELS Accommodations § 168.15-30 Toilet rooms. (a) There must be provided 1 toilet for each 10 persons or...

  17. Applying Structured Teaching Principles to Toilet Training.

    ERIC Educational Resources Information Center

    Boswell, Susan; Gray, Debbie

    This paper discusses toilet training children with autism using techniques recommended by TEACCH consultants. It recommends looking at the problem from the perspective of the student with autism in order to build in many elements of visual structure that will help the child understand exactly what is expected. Teachers are urged to look at each…

  18. Toilet Training and the Older Child

    MedlinePlus

    ... husband likes to tease me by calling my parenting style the ‘lazy parent’s method’ for raising a child,” writes one mother. “I like to just wait for my son to move on to the next stage of development and then follow his lead. He toilet-trained ...

  19. An Epiphany in a Toilet Factory

    ERIC Educational Resources Information Center

    Cobb, Catlin

    2009-01-01

    In this article, the author shares her experiences of the universality of art making and artistic experience of being a dancer and teaching artist. She describes her performance at Kohler, a worldwide leader in plumbing products in Spartanburg, South Carolina, where she had an epiphany dancing in a toilet factory--a sudden, intuitive moment of…

  20. A bacteriological survey of washrooms and toilets.

    PubMed Central

    Mendes, M. F.; Lynch, D. J.

    1976-01-01

    A survey of the bacterial flora present at various positions in 130 male and female washrooms and toilets is reported. Several bacteria of faecal origin were found in large numbers: the areas likely to be the most important sources of cross-infection from faecal contamination are indicated. The results are used to assess priorities for disinfection. PMID:1063213

  1. Perceptions of School Toilets as a Cause for Irregular Toilet Habits among Schoolchildren Aged 6 to 16 Years

    ERIC Educational Resources Information Center

    Lundblad, Barbro; Hellstrom, Anna-Lena

    2005-01-01

    Irregular bladder and bowel habits can contribute to urinary and bowel problems. Schoolchildren undergoing treatment for these problems often do not follow the recommendation of regular toilet visits at school, claiming negative perceptions of school toilets. This study examined 6- to 16-year-old schoolchildren's perceptions of school toilets and…

  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

    SciTech Connect

    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. CAD and CAE Analysis for Siphon Jet Toilet

    NASA Astrophysics Data System (ADS)

    Wang, Yuhua; Xiu, Guoji; Tan, Haishu

    The high precision 3D laser scanner with the dual CCD technology was used to measure the original design sample of a siphon jet toilet. The digital toilet model was constructed from the cloud data measured with the curve and surface fitting technology and the CAD/CAE systems. The Realizable k - ɛ double equation model of the turbulence viscosity coefficient method and the VOF multiphase flow model were used to simulate the flushing flow in the toilet digital model. Through simulating and analyzing the distribution of the flushing flow's total pressure, the flow speed at the toilet-basin surface and the siphoning bent tube, the toilet performance can be evaluated efficiently and conveniently. The method of "establishing digital model, flushing flow simulating, performances evaluating, function shape modifying" would provide a high efficiency approach to develop new water-saving toilets.

  4. Toileting. Functional Programming for People with Autism: Revised. A Series.

    ERIC Educational Resources Information Center

    Dalrymple, Nancy; Boarman, Margaret

    Self-care in toileting is one of the areas that persons with autism frequently have difficulty managing and are often confused by training. In developing a toilet training plan, critical factors include teaching the skill where it will be used, considering modesty concerns, communicating clear expectations, ruling out medical problems, and…

  5. Can't Make 'em Do It: Sleeping, Eating, Toileting

    ERIC Educational Resources Information Center

    Duffy, Roslyn

    2008-01-01

    Sleeping, eating, and toileting battles frustrate most adults--mainly because they cannot make children do it. Falling asleep (or not) is within a child's control. The same is true for chewing and swallowing, or withholding and releasing urine and feces. Sleeping, Eating, and Toileting (S.E.T.) create lots of frustration. An exhausted adult wants…

  6. 30 CFR 71.501 - Sanitary toilet facilities; maintenance.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Sanitary toilet facilities; maintenance. 71.501 Section 71.501 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR COAL MINE SAFETY AND HEALTH MANDATORY HEALTH STANDARDS-SURFACE COAL MINES AND SURFACE WORK AREAS OF UNDERGROUND COAL MINES Sanitary Toilet Facilities...

  7. 21 CFR 1250.44 - Drinking utensils and toilet articles.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Drinking utensils and toilet articles. 1250.44 Section 1250.44 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES... toilet articles. (a) No cup, glass, or other drinking utensil which may be used by more than one...

  8. 21 CFR 1250.44 - Drinking utensils and toilet articles.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Drinking utensils and toilet articles. 1250.44 Section 1250.44 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES... toilet articles. (a) No cup, glass, or other drinking utensil which may be used by more than one...

  9. A Parent Training Model for Toilet Training Children with Autism

    ERIC Educational Resources Information Center

    Kroeger, K.; Sorensen, R.

    2010-01-01

    Background: Azrin & Foxx pioneered an intensive toilet training protocol for individuals with intellectual disability living in a residential setting. Since the development of the Rapid Toilet Training (RTT) protocol, many have replicated the efficacy, most notably in educational and outpatient treatment settings, but often training over longer…

  10. Reduction of Microbial Aerosols by Automatic Toilet Bowl Cleaners.

    ERIC Educational Resources Information Center

    Yahya, Moyasar; And Others

    1992-01-01

    A study of the impact of automatic toilet bowl cleaners on aerosol generation. Three toilet bowl cleaners containing 2.5, 6.7 or 18.2 percent surfactant materials were evaluated. Results indicate these cleaners significantly (p 0.05) reduce bacteria ejected from the bowl, and the cleaner containing the greatest amount of surfactant was the most…

  11. 21 CFR 1250.44 - Drinking utensils and toilet articles.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Drinking utensils and toilet articles. 1250.44 Section 1250.44 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES... toilet articles. (a) No cup, glass, or other drinking utensil which may be used by more than one...

  12. 21 CFR 1250.44 - Drinking utensils and toilet articles.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Drinking utensils and toilet articles. 1250.44 Section 1250.44 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES... toilet articles. (a) No cup, glass, or other drinking utensil which may be used by more than one...

  13. The association of age of toilet training and dysfunctional voiding

    PubMed Central

    Hodges, Steve J; Richards, Kyle A; Gorbachinsky, Ilya; Krane, L Spencer

    2014-01-01

    Objective To determine whether age of toilet training is associated with dysfunctional voiding in children. Materials and methods We compared patients referred to the urologic clinics for voiding dysfunction with age-matched controls without urinary complaints. Characteristics including age and reason for toilet training, method of training, and encopresis or constipation were compared between both groups. Results Initiation of toilet training prior to 24 months and later than 36 months of age were associated with dysfunctional voiding. However, dysfunctional voiding due to late toilet training was also associated with constipation. Conclusion Dysfunctional voiding may be due to delayed emptying of the bowel and bladder by children. The symptoms of dysfunctional voiding are more common when toilet training early, as immature children may be less likely to empty in a timely manner, or when training late due to (or in association with) constipation. PMID:25328866

  14. Homicidal smothering on toilet paper: A case report.

    PubMed

    Saint-Martin, Pauline; Lefrancq, Thierry; Sauvageau, Anny

    2012-05-01

    Toilet paper is a ubiquitous personal hygiene product that is usually considered harmless. It was reported however to have been used as a mean of self-destruction in two unusual suicides, and is here reported to have been used to commit homicide. The body of a 91-year-old woman suffering from Alzheimer's disease was found in the bedroom of her nursing home, a roll of toilet paper near the body and toilet paper protruding from the mouth. At autopsy, pellets of toilet paper were impacted in the buccal cavity and the laryngopharynx above the epiglottis. The cause of death was established as smothering on toilet paper, whereas the manner of death was ruled as homicidal. Non-lethal blunt head injuries were considered to be a contributive factor, by lowering the victim's resistance. The perpetrator was another elderly woman, also suffering from Alzheimer's disease. PMID:22520378

  15. High School Students' Experiences in School Toilets or Restrooms.

    PubMed

    Norling, Maja; Stenzelius, Karin; Ekman, Nina; Wennick, Anne

    2016-06-01

    Previous research about school toilets is based on studies of children in elementary school. Thus, the aim of this study was to explore the experiences when using the school toilets reported by students aged 16-18 years. Qualitative interviews with 21 students were conducted and analyzed using content analysis. The data revealed that the toilets were considered insecure, dirty, and unpleasant. Additionally, students refrained from drinking during school hours and remained in constant movement or jumped up and down to withhold urine and stool. This was illustrated in the following categories: assessing the toilet environment, coping with the situation, and feeling exposed Hence, there is an urgent need to improve the school toilet environment in order to respect the rights of all students to void or defecate when necessary, a process which will require involvement of students, teachers, and other school staff as well as the School Health Service. PMID:26475260

  16. Sampling and analysis of the inactive waste tanks TH-2, WC-1, and WC-15. Environmental Restoration Program

    SciTech Connect

    Autrey, J.W.; Keller, J.M.; Griest, W.H.; Botts, J.L.; Schenley, R.L.; Sipe, M.A.

    1992-02-01

    Thirty-eight inactive liquid low-level radioactive waste tanks are currently managed by the Environmental Restoration Program of Oak Ridge National Laboratory. The contents of these tanks are to be characterized in preparation for future corrective actions and remediation activities as part of compliance with the pending Federal Facility Agreement for the Oak Ridge Reservation. Twenty-nine of these tanks were sampled and analyzed in 1989. Three of the tanks (TH-2, WC-1, and WC-15) were not accessible from the surface and thus were not sampled until 1990. This report presents the sampling and analytical results of that campaign. All three tanks in this report had negligible regulatory organic compounds in the samples that were collected. There were no US Environmental Protection Agency (EPA) Target Compound List (TCL) constituents for volatile organics detected in any of the aqueous samples. The only semivolatile organics detected were 2-chlorophenol (52 {mu}g/L) in tank TH-2 and dichloroethane (14--15 {mu}g/L) and diethyl either (15--17 {mu}g/L) in tank WC-15. A thin oil layer was discovered floating on top of the aqueous contents in tank WC-15. The analysis of the oil layer detected no volatile organics and showed only one EPA TCL constituent, di-n-butylphthalate, at 1900 {mu}g/L. Low levels of Resource Conservation and Recovery Act (RCRA) metals were observed in the samples from tank TH-2, but only the mercury level exceeded the RCRA limit. Samples from tank WC-1 had elevated levels of the RCRA metals barium, chromium, and lead. There were also finely suspended particles in one of the samples from tank WC-1, which was filtered and analyzed separately. This solid fines have levels of transuranium elements {sup 238}Pu and {sup 241}Am high enough to classified as transuranic waste.

  17. Factors associated with pupil toilet use in kenyan primary schools.

    PubMed

    Garn, Joshua V; Caruso, Bethany A; Drews-Botsch, Carolyn D; Kramer, Michael R; Brumback, Babette A; Rheingans, Richard D; Freeman, Matthew C

    2014-09-01

    The purpose of this study was to quantify how school sanitation conditions are associated with pupils' use of sanitation facilities. We conducted a longitudinal assessment in 60 primary schools in Nyanza Province, Kenya, using structured observations to measure facility conditions and pupils' use at specific facilities. We used multivariable mixed regression models to characterize how pupil to toilet ratio was associated with toilet use at the school-level and also how facility conditions were associated with pupils' use at specific facilities. We found a piecewise linear relationship between decreasing pupil to toilet ratio and increasing pupil toilet use (p < 0.01). Our data also revealed significant associations between toilet use and newer facility age (p < 0.01), facility type (p < 0.01), and the number of toilets in a facility (p < 0.01). We found some evidence suggesting facility dirtiness may deter girls from use (p = 0.06), but not boys (p = 0.98). Our study is the first to rigorously quantify many of these relationships, and provides insight into the complexity of factors affecting pupil toilet use patterns, potentially leading to a better allocation of resources for school sanitation, and to improved health and educational outcomes for children. PMID:25233014

  18. Factors Associated With Pupil Toilet Use in Kenyan Primary Schools

    PubMed Central

    Garn, Joshua V.; Caruso, Bethany A.; Drews-Botsch, Carolyn D.; Kramer, Michael R.; Brumback, Babette A.; Rheingans, Richard D.; Freeman, Matthew C.

    2014-01-01

    The purpose of this study was to quantify how school sanitation conditions are associated with pupils’ use of sanitation facilities. We conducted a longitudinal assessment in 60 primary schools in Nyanza Province, Kenya, using structured observations to measure facility conditions and pupils’ use at specific facilities. We used multivariable mixed regression models to characterize how pupil to toilet ratio was associated with toilet use at the school-level and also how facility conditions were associated with pupils’ use at specific facilities. We found a piecewise linear relationship between decreasing pupil to toilet ratio and increasing pupil toilet use (p < 0.01). Our data also revealed significant associations between toilet use and newer facility age (p < 0.01), facility type (p < 0.01), and the number of toilets in a facility (p < 0.01). We found some evidence suggesting facility dirtiness may deter girls from use (p = 0.06), but not boys (p = 0.98). Our study is the first to rigorously quantify many of these relationships, and provides insight into the complexity of factors affecting pupil toilet use patterns, potentially leading to a better allocation of resources for school sanitation, and to improved health and educational outcomes for children. PMID:25233014

  19. Mechanical property and wear performance dependence on processing condition for cold-sprayed WC-(nanoWC-Co)

    NASA Astrophysics Data System (ADS)

    Yang, Guan-Jun; Gao, Pei-Hu; Li, Cheng-Xin; Li, Chang-Jiu

    2015-03-01

    WC-(nanoWC-Co) with micro-WC reinforcing particles in nanoWC-Co cermet matrix was cold-sprayed by using WC-Co with bimodal sized WC particles (with both micro-sized WC particles and nano-sized WC particles). The effect of spray powder property and post-spray treatment on the mechanical properties and wear performance of cold-sprayed WC-(nanoWC-Co) coating were examined in comparison to the conventional high-velocity oxy-fuel (HVOF)-sprayed WC-Co coating. Results showed that both hardness and toughness were influenced by the spray powder properties and the post-spray heat treatment. Compared to the HVOF-sprayed WC-Co coating with micro-sized WC particles, WC-(nanoWC-Co) exhibited much higher hardness and toughness and thereby much higher wear resistance. The further toughening of WC-(nanoWC-Co) by post-spray heat treatment significantly doubled the wear performance. The excellent wear resistance of WC-(nanoWC-Co) is attributed to the simultaneous strengthening and toughening effects resulting from the microstructure design of bimodal WC particle size distribution composed of both micro-sized and nano-sized WC particles.

  20. Stages of Toilet Training: Different Skills, Different Schedules

    MedlinePlus

    ... Email Print Share Stages of Toilet Training: Different Skills, Different Schedules Page Content Article Body One of ... order and speed with which each of these skills is mastered may differ from child to child, ...

  1. 30. LOCKER CAGE, CHANGE AREA, TOILETS ABOVE ROOF PANEL STORAGE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    30. LOCKER CAGE, CHANGE AREA, TOILETS ABOVE ROOF PANEL STORAGE AREA. VIEW TO SOUTH. - Ford Motor Company Long Beach Assembly Plant, Assembly Building, 700 Henry Ford Avenue, Long Beach, Los Angeles County, CA

  2. Interior view of bath room 05 with original toilet stall, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Interior view of bath room 0-5 with original toilet stall, marble surround, and urinal, facing west. - Marine Barracks, Panama Canal, Barracks Building, 100' North of Thatcher Highway, Balboa, Former Panama Canal Zone, CZ

  3. Women's toilet with marble stalls and wooden doors, east end ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Women's toilet with marble stalls and wooden doors, east end of first floor. View to southwest. - San Bernardino Valley College, Life Science Building, 701 South Mount Vernon Avenue, San Bernardino, San Bernardino County, CA

  4. 9. View inside Building 802, "Toilet", facing east. Naval ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    9. View inside Building 802, "Toilet", facing east. - Naval Air Station Fallon, 100-man Fallout Shelter, 800 Complex, off Carson Road near intersection of Pasture & Berney Roads, Fallon, Churchill County, NV

  5. Psychological Readiness and Motor Skills Needed for Toilet Training

    MedlinePlus

    ... fully toilet-trained. Awareness of the Need to Go At around her first birthday, your child will ... child’s awareness of the feeling of needing to go so that she can build on this understanding ...

  6. 11. BEACH TOILET BUILDING, OFFICE AND FIRST AID BUILDING, PLANS, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    11. BEACH TOILET BUILDING, OFFICE AND FIRST AID BUILDING, PLANS, ELEVATIONS AND SECTIONS Drawing No. 103-07 - Glen Echo Park, Crystal Swimming Pool, 7300 McArthur Boulevard, Glen Echo, Montgomery County, MD

  7. 21. DETAIL, SECOND FLOOR MEN'S TOILET, SHOWING A CHANGE ROOM ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    21. DETAIL, SECOND FLOOR MEN'S TOILET, SHOWING A CHANGE ROOM AND A SHOWER. VIEW IS TO WEST NORTHWEST. - United Engineering Company Shipyard, Engineering Building, 2900 Main Street, Alameda, Alameda County, CA

  8. 27. OVERHEAD TOILET, SHOWER, CHANGE ROOM STRUCTURE. VIEW TO NORTHNORTHEAST. ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    27. OVERHEAD TOILET, SHOWER, CHANGE ROOM STRUCTURE. VIEW TO NORTH-NORTHEAST. - Ford Motor Company Long Beach Assembly Plant, Assembly Building, 700 Henry Ford Avenue, Long Beach, Los Angeles County, CA

  9. 4. VIEW OF WEST APRON, CARGO DOORS, SIDING AND TOILET ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    4. VIEW OF WEST APRON, CARGO DOORS, SIDING AND TOILET WINDOWS, LOOKING NORTHEAST - New York Barge Canal, Gowanus Bay Terminal Pier, East of bulkhead supporting Columbia Street, Brooklyn, Kings County, NY

  10. 46 CFR 92.20-25 - Washrooms and toilet rooms.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... attached. (b) The toilet rooms and washrooms must be located convenient to the sleeping quarters of the... private or semi-private facilities are provided and washbasins are installed in the sleeping rooms....

  11. 46 CFR 92.20-25 - Washrooms and toilet rooms.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... attached. (b) The toilet rooms and washrooms must be located convenient to the sleeping quarters of the... private or semi-private facilities are provided and washbasins are installed in the sleeping rooms....

  12. 46 CFR 92.20-25 - Washrooms and toilet rooms.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... attached. (b) The toilet rooms and washrooms must be located convenient to the sleeping quarters of the... private or semi-private facilities are provided and washbasins are installed in the sleeping rooms....

  13. FACILITY 846, TOILET AND SHOWER WINGS, QUADRANGLE J, OBLIQUE VIEW ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    FACILITY 846, TOILET AND SHOWER WINGS, QUADRANGLE J, OBLIQUE VIEW FACING WEST. - Schofield Barracks Military Reservation, Quadrangles I & J Barracks Type, Between Wright-Smith & Capron Avenues near Williston Avenue, Wahiawa, Honolulu County, HI

  14. 30. BATHROOM DETAIL SHOWING, BUILTIN CABINET, TOILET, AND OPEN DOOR ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    30. BATHROOM DETAIL SHOWING, BUILT-IN CABINET, TOILET, AND OPEN DOOR TO BACK BEDROOM. VIEW TO SOUTHWEST. - Bishop Creek Hydroelectric System, Control Station, Worker Cottage, Bishop Creek, Bishop, Inyo County, CA

  15. Overcoming Obstacles While Toilet Training an Older Child

    MedlinePlus

    ... an adult-size toilet as she imagines monsters crawling out to grab her or fears that she ... Academy of Pediatrics) The information contained on this Web site should not be used as a substitute ...

  16. 46 CFR 92.20-25 - Washrooms and toilet rooms.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... attached. (b) The toilet rooms and washrooms must be located convenient to the sleeping quarters of the... private or semi-private facilities are provided and washbasins are installed in the sleeping rooms....

  17. Harry Potter and the Terrors of the Toilet

    ERIC Educational Resources Information Center

    Mills, Alice

    2006-01-01

    The Harry Potter series focuses upon the toilet as a site for heroic action and a threshold between worlds as well as a more traditional place for boys to be bullied and girls to weep. This article offers a Kristevan reading of the toilets as abject in Harry Potter, and shows how this concept helps us make sense of wider issues within the series,…

  18. Method and device for disinfecting a toilet bowl

    DOEpatents

    Almon, Amy C.

    1997-01-01

    Method and device for disinfecting a flush toilet. The device is an electrocell mounted in the tank of the toilet, with two wire mesh electrodes immersed in the water in the tank and a battery applying approximately one to two volts of electric potential to the electrodes so that they chemically reduce a portion of the water in the tank to hydrogen peroxide. Then, when the tank is flushed, the peroxide is carried into the bowl where it can kill bacteria.

  19. A new approach to synthesize nano WC

    NASA Astrophysics Data System (ADS)

    Singh, Harjinder; Pandey, O. P.

    2013-06-01

    Tungsten carbide (WC) is extensively used in cutting and mining tools, dies and in wear resistance parts. The recent application of WC as electrocatalyst in fuel cells to replace costly nobel metal platinum (Pt) has further increased its demand. Its catalytic and mechanical properties are improved with the reduction of particle size in a nanometric range. The nano WC is synthesized from the pure precursor(s) which makes its production costly. In this work, we report a new process to get nano WC directly from the scheelite (CaWO4) ore. The powders were characterized by XRD, SEM and HRTEM.

  20. Microbiological investigations of rainwater and graywater collected for toilet flushing.

    PubMed

    Albrechtsen, H J

    2002-01-01

    Seven Danish rainwater systems were investigated with respect to the microbial water quality. The general microbiological quality (total numbers of bacteria (AODC)), and heterotrophic plate counts on R2A and Plate Count Agar in the toilets supplied with rainwater were approximately the same as in the reference toilets supplied with drinking water. However, in 12 of the 27 analysed samples one or more pathogens were observed (Aeromonas sp., Pseudomonas aeruginosa, Legionella non-pneumophila, Campylobacter jejuni, Mycobacterium avium, and Cryptosporidium sp.). These pathogens were not found in any of the reference toilets (32 toilets). This means that the use of rainwater introduced new, potentially pathogenic microorganisms into the households which would normally not occur in toilets supplied with water from waterworks. Furthermore, four graywater systems were investigated where water from the shower and hand wash basin was reused. The graywater systems gave more problems in terms of bad smell and substantially higher numbers of E. coli and Enterococcus in some toilet bowls supplied with graywater. PMID:12381006

  1. Palaeoparasitology in Japan--discovery of toilet features.

    PubMed

    Matsui, Akira; Kanehara, Masaaki; Kanehara, Masako

    2003-01-01

    The development of palaeoparasitology in Japan has occurred in recent decades. Despite the fact that archaeology in Japan has been slow to develop techniques for excavating ancient toilets, important information about the development of sanitation has been derived from the analysis of a few sites. This shows that the earliest people had very simple methods of sanitation. As populations increased, sanitation became more complex. Ditches surrounding early towns were used for excrement disposal. Eventually distinct toilets were developed followed by cesspit type toilets and flushing toilets. The parasites recovered from these toilets include many species that infect humans today. These parasite spectra reflect local use of aquatic, marine, and land animals. Fecal borne disease was an increasing problem as represented by whipworm and ascarid roundworm eggs. Interestingly, ascarid roundworms were absent in the earliest cultures and only became common with rice agriculture. Finds of pollen and seeds in toilet sediments reveal the use of medicinal plants to control the emerging problem of parasites. PMID:12687772

  2. Comparative study of nanocrystalline diamond deposition on WC-Ni and WC-Co substrates.

    PubMed

    Santos, J A; Neto, V F; Cabral, G; Ruch, D; Grácio, J

    2011-06-01

    Tungsten carbide alloys possess a large number of applications, due to its high hardness, high resistance to heat and to wear, which makes it ideal to be used in wear parts of machinery or on surfaces liable to corrosion, abrasion or high temperatures. For practical applications, it is alloyed with cobalt (Co) or nickel (Ni) in order to improve its properties. The increasing demand of broadening the operation limits of some components, impose the need to improve its life time. Coating these parts with hard and smooth diamond thin film may improve the wear performance and decrease their roughness and friction coefficient. In this work, a comparative study of nanodiamond films deposit onto WC-Co and WC-Ni, by means of a hot-filament Chemical Vapour Deposition (HFCVD) system, is presented. The study was accomplished by varying the CH4/H2/Ar gas ratio of the deposition process. The substrate temperature was kept low (< 700 degrees C) to minimize the thermal stress in the coating-substrate system. The microstructure of the deposited diamond film was characterized using Scanning Electron Microscopy (SEM), Raman spectroscopy and X-ray diffraction spectroscopy. Roughness of the working surfaces were also accessed prior and after the depositions. PMID:21770193

  3. Accessibility

    MedlinePlus

    ... www.nlm.nih.gov/medlineplus/accessibility.html MedlinePlus Accessibility To use the sharing features on this page, ... Subscribe to RSS Follow us Disclaimers Copyright Privacy Accessibility Quality Guidelines Viewers & Players MedlinePlus Connect for EHRs ...

  4. A sustainable approach towards rural development: dry toilets in Nepal.

    PubMed

    Regmi, M R

    2005-01-01

    Existing inadequate sewerage systems and direct disposal of household waste into water courses has tremendously increased water pollution. Dry toilets are feasible in rural and peri-urban areas to reduce the consumption of costlier water that is required for flushing. As conventional treatment technologies require high investment, and operation and maintenance costs, dry toilets are the only suitable option left for sanitation in the 21st century when working with limited financial resources. To reduce environmental degradation and overcome this problem, the dry toilet is only the realistic option in Nepal. Two reactors, one exposed to sunrays and the other without sunrays, were constructed. In the model with sunrays, it was found that in 48 days of observation faecal coliform presence depleted to 610 cells per gm from the initial value of 7 x 10(10) and volatile organic matter came down from 98.09% to 70.18%. Similarly, in the other model, the destruction of faecal coliform in 65 days was found to be 920 cells/gm while the destruction of organic matter took 75 days. Also, observing from 313 people in a cluster on the pilot project, the annually recovered value of N, P and K was found to be 1565 kg, 125 kg, 344 kg, respectively. This paper deals with the different types of dry ecological toilet, their performance and feasibility study in Nepal, with the full involvement of local people, based on complete laboratory analysis and regular monitoring. Using dry toilets will save 14 LPCD, which is equivalent to 14 MLD and the resulting demand will become only 80 MLD for the urban area of Kathmandu. The result advocates the implementation of ecological dry toilets to save valuable water wasted in flushing, as well as saving the resources needed to treat the waste. PMID:16477967

  5. Synthesis of nanocrystalline tungsten carbide (WC) powder

    NASA Astrophysics Data System (ADS)

    Singla, Gourav; Singh, K.; Pandey, O. P.

    2013-06-01

    Nanocrystalline tungsten carbide (WC) has been obtained from bulk WO3 by in situ reduction and carbonization reactions at low temperature (˜ 600 °C) by taking Mg as reductant and acetone C3H6O as carbon source. It was aimed to elucidate carburization behavior of WO3 powder and to establish optimal conditions for the synthesis of nanocrystalline WC. The role of reaction time on the synthesis of WC has been investigated and discussed. The synthesized powders were characterized by X-ray powder diffraction, differential thermal analyzer (DTA), thermo gravimetric analysis (TGA).

  6. 46 CFR 32.40-25 - Washrooms and toilet rooms-T/ALL.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    .... (a) At least 1 toilet, 1 washbasin, and 1 shower or bathtub must be provided for each 8 members or... be equipped with adequate plumbing, including hot and cold running water. All toilets must...

  7. Method and device for disinfecting a toilet bowl

    DOEpatents

    Almon, A.C.

    1997-03-18

    Method and device are disclosed for disinfecting a flush toilet. The device is an electrolytic cell mounted in the tank of the toilet, with two wire mesh electrodes immersed in the water in the tank and a battery applying approximately one to two volts of electric potential to the electrodes so that they chemically reduce a portion of the water in the tank to hydrogen peroxide. Then, when the tank is flushed, the peroxide is carried into the bowl where it can kill bacteria. 2 figs.

  8. Method and device for disinfecting a toilet bowl

    SciTech Connect

    Almon, A.C.

    1992-12-31

    This invention is comprised of a method and device for disinfecting a flush toilet. The device is an electrocell mounted in the tank of the toilet, with two wire mesh electrodes immersed in the water in the tank and a battery applying approximately one to two volts of electric potential to the electrodes so that they chemically reduce a portion of the water in the tank to hydrogen peroxide. Then, when the tank is flushed, the peroxide is carried into the bowl where it can kill bacteria.

  9. Unobtrusive and comprehensive health screening using an intelligent toilet system.

    PubMed

    Schlebusch, Thomas; Fichtner, Wolfgang; Mertig, Michael; Leonhardt, Steffen

    2015-02-01

    Home monitoring is a promising technology to deal with the increasing amount of chronically ill patients while ensuring quality of medical care. Most systems available today depend on a high degree of interaction between the user and the device. Especially for people relying on advanced levels of care, this scheme is impracticable. In this paper, we are presenting an "intelligent toilet" performing an extensive health check while being as simple to use as a conventional toilet. The main focus of the system is to support the treatment of diabetes and chronic heart failure, but additional applications are possible. PMID:25324433

  10. 30 CFR 71.500 - Sanitary toilet facilities at surface work sites; installation requirements.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Sanitary toilet facilities at surface work... SURFACE WORK AREAS OF UNDERGROUND COAL MINES Sanitary Toilet Facilities at Surface Worksites of Surface Coal Mines § 71.500 Sanitary toilet facilities at surface work sites; installation requirements....

  11. 30 CFR 71.500 - Sanitary toilet facilities at surface work sites; installation requirements.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Sanitary toilet facilities at surface work... SURFACE WORK AREAS OF UNDERGROUND COAL MINES Sanitary Toilet Facilities at Surface Worksites of Surface Coal Mines § 71.500 Sanitary toilet facilities at surface work sites; installation requirements....

  12. Effectiveness of a Modified Rapid Toilet Training Workshop for Parents of Children with Developmental Disabilities

    ERIC Educational Resources Information Center

    Rinald, Katherine; Mirenda, Pat

    2012-01-01

    Individuals with developmental disabilities often experience challenges in acquiring toileting skills, which highlights a need for effective toilet training strategies that can be readily disseminated to caregivers. The purpose of this multiple baseline study was to evaluate the effectiveness of a modified rapid toilet training workshop provided…

  13. Single-Case Evaluation of a Negative Reinforcement Toilet Training Intervention

    ERIC Educational Resources Information Center

    Luiselli, James K.

    2007-01-01

    A negative reinforcement intervention was used to toilet train a child with multiple disabilities. The child appeared to actively withhold urinating in the toilet and was unresponsive to two positive reinforcement training programs. Negative reinforcement required that the child remain in the bathroom during toileting opportunities until he…

  14. 33. Elevation of Doors / Typical Cement Toilet Partitions / ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    33. Elevation of Doors / Typical Cement Toilet Partitions / Typical Cement Shower Bath Partitions / Typical Marble Shower Bath Partitions / Dispensary Cupboard Supply Room Cupboard Similar / Section / Kitchen Cupboard and Sink / Screened Porch Cupboard (drawing 10) - Whittier State School, Hospital & Receiving Building, 11850 East Whittier Boulevard, Whittier, Los Angeles County, CA

  15. NORTH AMERICAN AND EUROPEAN EXPERIENCE WITH BIOLOGICAL TOILETS

    EPA Science Inventory

    A history of North American and European experience with biological toilets is provided. The early use of these devices in Scandanavia was to solve a specific problem, that of providing a low-cost solution for disposing of human wastes from recreational cabins. Because of their e...

  16. 30 CFR 75.1712 - Bath houses and toilet facilities.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Bath houses and toilet facilities. 75.1712 Section 75.1712 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR COAL MINE SAFETY AND HEALTH MANDATORY SAFETY STANDARDS-UNDERGROUND COAL MINES Miscellaneous § 75.1712 Bath...

  17. 30 CFR 75.1712 - Bath houses and toilet facilities.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Bath houses and toilet facilities. 75.1712 Section 75.1712 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR COAL MINE SAFETY AND HEALTH MANDATORY SAFETY STANDARDS-UNDERGROUND COAL MINES Miscellaneous § 75.1712 Bath...

  18. 30 CFR 75.1712 - Bath houses and toilet facilities.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Bath houses and toilet facilities. 75.1712 Section 75.1712 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR COAL MINE SAFETY AND HEALTH MANDATORY SAFETY STANDARDS-UNDERGROUND COAL MINES Miscellaneous § 75.1712 Bath...

  19. 30 CFR 75.1712 - Bath houses and toilet facilities.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Bath houses and toilet facilities. 75.1712 Section 75.1712 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR COAL MINE SAFETY AND HEALTH MANDATORY SAFETY STANDARDS-UNDERGROUND COAL MINES Miscellaneous § 75.1712 Bath...

  20. 30 CFR 75.1712 - Bath houses and toilet facilities.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Bath houses and toilet facilities. 75.1712 Section 75.1712 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR COAL MINE SAFETY AND HEALTH MANDATORY SAFETY STANDARDS-UNDERGROUND COAL MINES Miscellaneous § 75.1712 Bath...

  1. FIELD INVESTIGATION OF BIOLOGICAL TOILET SYSTEMS AND GREY WATER TREATMENT

    EPA Science Inventory

    The objective of the field program was to determine the operational characteristics and overall acceptability of popular models of biological toilets and a few select grey water systems. A field observation scheme was devised to take advantage of in-use sites throughout the State...

  2. Toilet Training in the Sheltered Workshop--Why Not?

    ERIC Educational Resources Information Center

    Olofsson, Gunilla; Karan, Orv. C.

    1976-01-01

    The present case study describes a toilet training program planned, developed, and implemented within a sheltered workshop. The client was a severely retarded woman for whom incontinence had been a life-long problem. The ease with which the program was carried out recommends its use with similar client problems. (Author)

  3. 46 CFR 72.20-25 - Washrooms and toilet rooms.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... who do not occupy sleeping accommodations to which private or semi-private facilities are attached. (b) The toilet rooms and washrooms shall be located convenient to the sleeping quarters of the crew to... semi-private facilities are provided and washbasins are installed in the sleeping rooms. (e) Where...

  4. 46 CFR 72.20-25 - Washrooms and toilet rooms.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... who do not occupy sleeping accommodations to which private or semi-private facilities are attached. (b) The toilet rooms and washrooms shall be located convenient to the sleeping quarters of the crew to... semi-private facilities are provided and washbasins are installed in the sleeping rooms. (e) Where...

  5. 46 CFR 72.20-25 - Washrooms and toilet rooms.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... who do not occupy sleeping accommodations to which private or semi-private facilities are attached. (b) The toilet rooms and washrooms shall be located convenient to the sleeping quarters of the crew to... semi-private facilities are provided and washbasins are installed in the sleeping rooms. (e) Where...

  6. 17. INTERIOR OF BATHROOM SHOWING TOILET AT EXTREME PHOTO LEFT, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    17. INTERIOR OF BATHROOM SHOWING TOILET AT EXTREME PHOTO LEFT, SINK, MIRROR AND ELECTRIC LIGHT AT LEFT PHOTO CENTER, OPEN AND CLOSED BUILT-IN CABINETRY AT PHOTO CENTER AND THE BATHTUB AT EXTREME PHOTO RIGHT. VIEW TO SOUTHWEST. - Bishop Creek Hydroelectric System, Plant 4, Worker Cottage, Bishop Creek, Bishop, Inyo County, CA

  7. 21 CFR 211.52 - Washing and toilet facilities.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 4 2012-04-01 2012-04-01 false Washing and toilet facilities. 211.52 Section 211.52 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) DRUGS: GENERAL CURRENT GOOD MANUFACTURING PRACTICE FOR FINISHED PHARMACEUTICALS Buildings and...

  8. 21 CFR 211.52 - Washing and toilet facilities.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 4 2013-04-01 2013-04-01 false Washing and toilet facilities. 211.52 Section 211.52 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) DRUGS: GENERAL CURRENT GOOD MANUFACTURING PRACTICE FOR FINISHED PHARMACEUTICALS Buildings and...

  9. 21 CFR 211.52 - Washing and toilet facilities.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 4 2014-04-01 2014-04-01 false Washing and toilet facilities. 211.52 Section 211.52 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) DRUGS: GENERAL CURRENT GOOD MANUFACTURING PRACTICE FOR FINISHED PHARMACEUTICALS Buildings and...

  10. 46 CFR 169.319 - Washrooms and toilets.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) NAUTICAL SCHOOLS SAILING SCHOOL VESSELS Construction and Arrangement Living Spaces § 169.319 Washrooms and toilets. (a) Sailing school vessels must... sufficient size and situated in the lowest part of the space. (c) Each sailing school vessel must meet...

  11. 46 CFR 169.319 - Washrooms and toilets.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) NAUTICAL SCHOOLS SAILING SCHOOL VESSELS Construction and Arrangement Living Spaces § 169.319 Washrooms and toilets. (a) Sailing school vessels must... sufficient size and situated in the lowest part of the space. (c) Each sailing school vessel must meet...

  12. 46 CFR 169.319 - Washrooms and toilets.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) NAUTICAL SCHOOLS SAILING SCHOOL VESSELS Construction and Arrangement Living Spaces § 169.319 Washrooms and toilets. (a) Sailing school vessels must... sufficient size and situated in the lowest part of the space. (c) Each sailing school vessel must meet...

  13. 46 CFR 169.319 - Washrooms and toilets.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) NAUTICAL SCHOOLS SAILING SCHOOL VESSELS Construction and Arrangement Living Spaces § 169.319 Washrooms and toilets. (a) Sailing school vessels must... sufficient size and situated in the lowest part of the space. (c) Each sailing school vessel must meet...

  14. 46 CFR 169.319 - Washrooms and toilets.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) NAUTICAL SCHOOLS SAILING SCHOOL VESSELS Construction and Arrangement Living Spaces § 169.319 Washrooms and toilets. (a) Sailing school vessels must... sufficient size and situated in the lowest part of the space. (c) Each sailing school vessel must meet...

  15. 46 CFR 72.20-25 - Washrooms and toilet rooms.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... who do not occupy sleeping accommodations to which private or semi-private facilities are attached. (b) The toilet rooms and washrooms shall be located convenient to the sleeping quarters of the crew to... semi-private facilities are provided and washbasins are installed in the sleeping rooms. (e) Where...

  16. The Potential of Wash-and-Dry Toilets to Improve the Toileting Experience for Nursing Home Residents

    ERIC Educational Resources Information Center

    Cohen-Mansfield, Jiska; Biddison, James R.

    2005-01-01

    Purpose: We investigated the feasibility of using a "wash-and-dry" toilet in the nursing home. Design and Methods: We used a controlled comparison baseline-versus-treatment design with 22 female nursing home residents aged 75 and older living in a 562-bed, not-for-profit nursing home facility in Maryland. The Luscence Luxury Lavage wash-and-dry…

  17. WC19: a wheelchair transportation safety standard--experience to date and future directions.

    PubMed

    Manary, Miriam A; Ritchie, Nichole L; Schneider, Lawrence W

    2010-04-01

    ANSI/RESNA WC19 (i.e., WC19) is a voluntary standard that specifies design and performance requirements for wheelchairs that are suitable for use as seats in motor vehicles. The guiding principles for the standard originate from automotive crash-protection principles that are effective in reducing occupant injuries and fatalities. In addition to frontal-impact testing of wheelchairs, the standard includes tests for securement-point accessibility, tiedown-strap clear paths, lateral stability, and accommodation of vehicle-anchored belt restraints. Results from testing wheelchairs to WC19 reveal that the most common wheelchair problems include: a lack of structural integrity during frontal-impact loading; sharp rigid edges; and wheelchair structures that interfere with achieving proper positioning of vehicle-anchored belt restraints. Data from 8 years of experience with WC19 indicate where changes are needed to further improve transportation safety for wheelchair-seated travelers. These include expanding WC19 to include wheelchairs for smaller children who require a five-point harness restraint, and requiring wheelchairs to achieve a minimal rating for the ease of achieving proper positioning of vehicle-anchored belt restraints. PMID:19782631

  18. APT analysis of WC-Co based cemented carbides.

    PubMed

    Weidow, Jonathan; Andrén, Hans-Olof

    2011-05-01

    A method for quickly producing sharp and site-specific atom probe specimens from WC-Co based cemented carbides was developed using a combination of electropolishing, controlled back-polishing and FIB milling. Also, a method for measuring the amount of segregated atoms to an interface between two phases with a big difference in field needed for field evaporation was developed. Using atom probe tomography, the interface chemistry of WC/WC grain boundaries, WC/(M,W)C phase boundaries and WC/binder phase boundaries was analysed. In addition, the transition metal solubility in WC was determined. PMID:21664543

  19. Treatment of toilet wastewater for reuse in a membrane bioreactor.

    PubMed

    Boehler, M; Joss, A; Buetzer, S; Holzapfel, M; Mooser, H; Siegrist, H

    2007-01-01

    Toilet wastewater is treated and reused on site at Europe's highest membrane bioreactor (MBR), located in a cable car mountain station in the ski resort of Zermatt. Negative impacts on the sensitive mountain environment are minimised by reusing close to 100% of the treated wastewater for toilet flushing. Besides 100% nitrogen removal, 80% of phosphorus was also eliminated. This paper presents operational results, optimisations of sludge management, decoloration and long-term maintenance of biomass in the very low-loaded summer season. From a global view the experiences and results of the project are of great importance, proposing a solution to a problem existing 100-fold in the Alps as well as in arid regions all over the world: reducing water consumption for sanitation by reuse. PMID:17881838

  20. Electrochemical disinfection of toilet wastewater using wastewater electrolysis cell.

    PubMed

    Huang, Xiao; Qu, Yan; Cid, Clément A; Finke, Cody; Hoffmann, Michael R; Lim, Keahying; Jiang, Sunny C

    2016-04-01

    The paucity of proper sanitation facilities has contributed to the spread of waterborne diseases in many developing countries. The primary goal of this study was to demonstrate the feasibility of using a wastewater electrolysis cell (WEC) for toilet wastewater disinfection. The treated wastewater was designed to reuse for toilet flushing and agricultural irrigation. Laboratory-scale electrochemical (EC) disinfection experiments were performed to investigate the disinfection efficiency of the WEC with four seeded microorganisms (Escherichia coli, Enterococcus, recombinant adenovirus serotype 5, and bacteriophage MS2). In addition, the formation of organic disinfection byproducts (DBPs) trihalomethanes (THMs) and haloacetic acids (HAA5) at the end of the EC treatment was also investigated. The results showed that at an applied cell voltage of +4 V, the WEC achieved 5-log10 reductions of all four seeded microorganisms in real toilet wastewater within 60 min. In contrast, chemical chlorination (CC) disinfection using hypochlorite [NaClO] was only effective for the inactivation of bacteria. Due to the rapid formation of chloramines, less than 0.5-log10 reduction of MS2 was observed in toilet wastewater even at the highest [NaClO] dosage (36 mg/L, as Cl2) over a 1 h reaction. Experiments using laboratory model waters showed that free reactive chlorine generated in situ during EC disinfection process was the main disinfectant responsible for the inactivation of microorganisms. However, the production of hydroxyl radicals [OH], and other reactive oxygen species by the active bismuth-doped TiO2 anode were negligible under the same electrolytic conditions. The formation of THMs and HAA5 were found to increase with higher applied cell voltage. Based on the energy consumption estimates, the WEC system can be operated using solar energy stored in a DC battery as the sole power source. PMID:26854604

  1. Electrochemical disinfection of toilet wastewater using wastewater electrolysis cell

    PubMed Central

    Huang, Xiao; Qu, Yan; Cid, Clément A.; Finke, Cody; Hoffmann, Michael R.; Lim, Keahying; Jiang, Sunny C.

    2016-01-01

    The paucity of proper sanitation facilities has contributed to the spread of waterborne diseases in many developing countries. The primary goal of this study was to demonstrate the feasibility of using a wastewater electrolysis cell (WEC) for toilet wastewater disinfection. The treated wastewater was designed to reuse for toilet flushing and agricultural irrigation. Laboratory-scale electrochemical (EC) disinfection experiments were performed to investigate the disinfection efficiency of the WEC with four seeded microorganisms (Escherichia coli, Enterococcus, recombinant adenovirus serotype 5, and bacteriophage MS2). In addition, the formation of organic disinfection byproducts (DBPs) trihalomethanes (THMs) and haloacetic acids (HAA5) at the end of the EC treatment was also investigated. The results showed that at an applied cell voltage of +4 V, the WEC achieved 5-log10 reductions of all four seeded microorganisms in real toilet wastewater within 60 min. In contrast, chemical chlorination (CC) disinfection using hypochlorite [NaClO] was only effective for the inactivation of bacteria. Due to the rapid formation of chloramines, less than 0.5-log10 reduction of MS2 was observed in toilet wastewater even at the highest [NaClO] dosage (36 mg/L, as Cl2) over a 1 h reaction. Experiments using laboratory model waters showed that free reactive chlorine generated in situ during EC disinfection process was the main disinfectant responsible for the inactivation of microorganisms. However, the production of hydroxyl radicals [•OH], and other reactive oxygen species by the active bismuth-doped TiO2 anode were negligible under the same electrolytic conditions. The formation of THMs and HAA5 were found to increase with higher applied cell voltage. Based on the energy consumption estimates, the WEC system can be operated using solar energy stored in a DC battery as the sole power source. PMID:26854604

  2. Do piped water and flush toilets prevent child diarrhea in rural Philippines?

    PubMed

    Capuno, Joseph J; Tan, Carlos Antonio R; Fabella, Vigile Marie

    2015-03-01

    Similar to other developing countries, diarrhea in the Philippines continues to be among the top causes of child mortality and morbidity. In pursuit of its Millennium Development Goals, the Philippine government commits to reduce child deaths and provide water and sanitation services to more rural households by 2015. Applying propensity score matching on the 1993, 1998, 2003, and 2008 rounds of the National Demographic and Health Survey to estimate the average treatment effect on the treated, it is found that the incidence of diarrhea among under-5 children is lower by as much as 4.5% in households with access to piped water and 10% in those with their own flush toilets, relative to comparable households. These findings underscore the need to ensure the quality of drinking water from the pipe or from other improved sources at the point of use, and the provision of improved and own sanitation facilities. PMID:22186402

  3. Quantitative analysis of WC grain shape in sintered WC-Co cemented carbides.

    PubMed

    Christensen, Mikael; Wahnström, Göran; Allibert, Colette; Lay, Sabine

    2005-02-18

    The morphology of WC grains is examined by ab initio calculations, and by transmission electron microscopy in a WC-Co cemented carbide. Two compositions are studied to determine the effect of carbon chemical potential on the shape development. The WC grains are found to be truncated triangles, and the grain morphology is adequately reproduced by the ab initio calculations. The energy difference between the two types of grain facets is shown to be due to the formation of stronger bonds with more covalent character between low coordinated W and Co atoms at one type of facet. PMID:15783755

  4. Metal modified tungsten carbide (WC) for catalytic and electrocatalytic applications

    NASA Astrophysics Data System (ADS)

    Mellinger, Zachary J.

    One of the major challenges in the commercialization of proton exchange membrane fuel cells (PEMFC) is the cost, and low CO tolerance of the anode electrocatalyst material. The anode typically requires a high loading of precious metal electrocatalyst (Pt or Pt--Ru) to obtain a useful amount of electrical energy from the electrooxidation of methanol (CH3OH) or ethanol (C2H5OH). The complete electro--oxidation of methanol or ethanol on these catalysts produces strongly adsorbed CO on the surface, which reduces the activity of the Pt or Pt--Ru catalysts. Another major disadvantage of these electrocatalyst components is the scarcity and consequently high price of both Pt and Ru. Tungsten monocarbide (WC) has shown similar catalytic properties to Pt, leading to the utilization of WC and metal modified WC as replacements to Pt and Pt--Ru. In this thesis we investigated WC and Pt--modified WC as a potentially more CO--tolerant electrocatalysts as compared to pure Pt. These catalysts would reduce or remove the high loading of Pt used industrially. The binding energy of CO, estimated using temperature programmed desorption, is weaker on WC and Pt/WC than on Pt, suggesting that it should be easier to oxidize CO on WC and Pt/WC. This hypothesis was verified using cyclic voltammetry to compare the electro--oxidation of CO on WC, Pt/WC, and Pt supported on carbon substrates, which showed a lower voltage for the onset of oxidation of CO on WC and Pt/WC than on Pt. After observing these improved properties on the Pt/WC catalysts, we decided to expand our studies to investigate Pd--modified WC as Pd is less expensive than Pt and has shown more ideal properties for alcohol electrocatalysis in alkaline media. Pd/WC showed a lower binding energy of CO than both its parent metal Pd as well as Pt. Then, density functional theory (DFT) calculations were performed to determine how the presence of Pd affected the bonding of methanol and ethanol on the WC surface. The DFT studies showed

  5. Slum inhabitants' perceptions and decision-making processes related to an innovative sanitation service: evaluating the Blue Diversion Toilet in Kampala (Uganda).

    PubMed

    O'Keefe, Mark; Messmer, Ulrike; Lüthi, Christoph; Tobias, Robert

    2015-01-01

    The inadequate provision of sanitation in informal urban settlements, also known as slums, continues to be an important issue. New technologies and services are being designed to solve this problem. However, the history of failed sanitation programmes and projects highlights a lack of understanding of how slum inhabitants decide on investing in such products and services. In this paper, we gather perspectives from potential clients and investigate how slum inhabitants (1) perceive the current situation and whether they desire improvements of sanitation, (2) how they evaluate a new toilet that is still in development, and how (3) social processes and (4) constraints affect decisions. Data were collected through interviewing 1538 people within a general household survey. People using shared and public latrines desire an improvement of their sanitation facilities. The lack of water for washing is perceived by residents as a the biggest problem when accessing current latrines. The new toilet was mostly evaluated positively: people like it, expect large health benefits from it and it complies with cultural norms. However, people also expect some problems with the functioning of the toilet and expect opposition to pay for the service, due to the high costs and a lack of space to set up new toilets. PMID:25684115

  6. Microstructure and Sliding Wear Resistance of Laser Cladded WC/Ni Composite Coatings with Different Contents of WC Particle

    NASA Astrophysics Data System (ADS)

    Xu, J. S.; Zhang, X. C.; Xuan, F. Z.; Wang, Z. D.; Tu, S. T.

    2012-09-01

    The aim of this article was to address the effect of WC content on the microstructure, microhardness, and sliding wear resistance of laser cladded WC/Ni composite coatings. The content of WC particle in the feed powder varied in the range of 0-80 wt.%. Experimental results showed that the laser cladded coatings exhibited homogeneous microstructure without pores or cracks. By comparing with the 45# steel substrate, the microhardness of WC/Ni composite coatings was relatively high. The microhardness of coating increased with increasing the content of WC particles. The wear resistance of WC/Ni composite coatings was strongly dependent on the content of WC particle and their microstructure. When the WC content was lower than 40 wt.% in the feed powder, the wear rate of the coatings decreased with increasing WC content. The two-body abrasive wear was identified as the main wear mechanisms. For the coatings with WC content higher than 40 wt.% in the feed powder, their wear rate increased with increasing WC content. The three-body abrasive wear and fatigue wear were the main failures. The coating with 40 wt.% WC in the feed powder exhibited the best wear resistance.

  7. Lifting the lid on toilet plume aerosol: A literature review with suggestions for future research

    PubMed Central

    Johnson, David L.; Mead, Kenneth R.; Lynch, Robert A.; Hirst, Deborah V.L.

    2015-01-01

    Background The potential risks associated with “toilet plume” aerosols produced by flush toilets is a subject of continuing study. This review examines the evidence regarding toilet plume bioaerosol generation and infectious disease transmission. Methods The peer-reviewed scientific literature was searched to identify articles related to aerosol production during toilet flushing, as well as epidemiologic studies examining the potential role of toilets in infectious disease outbreaks. Results The studies demonstrate that potentially infectious aerosols may be produced in substantial quantities during flushing. Aerosolization can continue through multiple flushes to expose subsequent toilet users. Some of the aerosols desiccate to become droplet nuclei and remain adrift in the air currents. However, no studies have yet clearly demonstrated or refuted toilet plume-related disease transmission, and the significance of the risk remains largely uncharacterized. Conclusion Research suggests that toilet plume could play a contributory role in the transmission of infectious diseases. Additional research in multiple areas is warranted to assess the risks posed by toilet plume, especially within health care facilities. PMID:23040490

  8. Survival of fecal coliforms in dry-composting toilets.

    PubMed

    Redlinger, T; Graham, J; Corella-Barud, V; Avitia, R

    2001-09-01

    The dry-composting toilet, which uses neither water nor sewage infrastructure, is a practical solution in areas with inadequate sewage disposal and where water is limited. These systems are becoming increasingly popular and are promoted to sanitize human excreta and to recycle them into fertilizer for nonedible plants, yet there are few data on the safety of this technology. This study analyzed fecal coliform reduction in approximately 90 prefabricated, dry-composting toilets (Sistema Integral de Reciclamiento de Desechos Orgánicos [SIRDOs]) that were installed on the U.S.-Mexico border in Ciudad Juárez, Chihuahua, Mexico. The purpose of this study was to determine fecal coliform reduction over time and the most probable method of this reduction. Biosolid waste samples were collected and analyzed at approximately 3 and 6 months and were classified based on U.S. Environmental Protection Agency standards. Results showed that class A compost (high grade) was present in only 35.8% of SIRDOs after 6 months. The primary mechanism for fecal coliform reduction was found to be desiccation rather than biodegradation. There was a significant correlation (P = 0.008) between classification rating and percent moisture categories of the biosolid samples: drier samples had a greater proportion of class A samples. Solar exposure was critical for maximal class A biosolid end products (P = 0.001). This study only addressed fecal coliforms as an indicator organism, and further research is necessary to determine the safety of composting toilets with respect to other pathogenic microorganisms, some of which are more resistant to desiccation. PMID:11526002

  9. A dual composite of WC-Co

    SciTech Connect

    Fang, Z.; Lockwood, G.; Griffo, A.

    1999-12-01

    Hardness, fracture toughness, and wear resistance are strongly inter-related properties of cemented tungsten carbide. Higher hardness usually dictates higher wear resistance but at the cost of fracture toughness. A new dual composite of WC-Co, named DC carbide, is reported in this article. The new, hybrid, particulate composite material has higher fracture toughness than conventional WC-Co material at equivalent wear resistance. Moreover, it has higher wear resistance at equivalent fracture toughness when compared to tool steels. The improved properties are achieved by the composite microstructure that maximizes mean free path (MFP) between hard reinforcement particles. The new composite material is also unique in that the reinforcement phase is a composite material in and of itself.

  10. Listening to carers talking about the subjects of continence and toileting.

    PubMed

    Forbat, Liz

    Toilets and continence play critical roles in the lives of people who care for a relative at home. Issues around toileting are central to the relationship between the carer and the person being cared for, with the bathroom often becoming the most important place in the house. PMID:14768154

  11. A Component Analysis of Toilet-Training Procedures Recommended for Young Children

    ERIC Educational Resources Information Center

    Greer, Brian D.; Neidert, Pamela L.; Dozier, Claudia L.

    2016-01-01

    We evaluated the combined and sequential effects of 3 toilet-training procedures recommended for use with young children: (a) underwear, (b) a dense sit schedule, and (c) differential reinforcement. A total of 20 children participated. Classroom teachers implemented a toilet-training package consisting of all 3 procedures with 6 children. Of the 6…

  12. Teaching a Child with Challenging Behaviour to Use the Toilet: A Clinical Case Study

    ERIC Educational Resources Information Center

    Brown, Freddy Jackson; Peace, Natalie

    2011-01-01

    Learning to use the toilet is an important developmental step for a child's independence, health and dignity. It can be particularly difficult to teach continence skills to disabled children with aggressive or challenging behaviour. This study showed how Azrin & Foxx's (1971) basic toilet training procedure could be modified to teach a 13-year-old…

  13. 46 CFR 108.205 - Wash spaces; toilet spaces; and shower spaces.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 4 2010-10-01 2010-10-01 false Wash spaces; toilet spaces; and shower spaces. 108.205... DRILLING UNITS DESIGN AND EQUIPMENT Construction and Arrangement Accommodation Spaces § 108.205 Wash spaces; toilet spaces; and shower spaces. (a) For the purposes of this section— (1) “Private facility” means...

  14. 46 CFR 108.205 - Wash spaces; toilet spaces; and shower spaces.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 4 2013-10-01 2013-10-01 false Wash spaces; toilet spaces; and shower spaces. 108.205... DRILLING UNITS DESIGN AND EQUIPMENT Construction and Arrangement Accommodation Spaces § 108.205 Wash spaces; toilet spaces; and shower spaces. (a) For the purposes of this section— (1) “Private facility” means...

  15. 46 CFR 108.205 - Wash spaces; toilet spaces; and shower spaces.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 4 2014-10-01 2014-10-01 false Wash spaces; toilet spaces; and shower spaces. 108.205... DRILLING UNITS DESIGN AND EQUIPMENT Construction and Arrangement Accommodation Spaces § 108.205 Wash spaces; toilet spaces; and shower spaces. (a) For the purposes of this section— (1) “Private facility” means...

  16. 46 CFR 108.205 - Wash spaces; toilet spaces; and shower spaces.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 4 2012-10-01 2012-10-01 false Wash spaces; toilet spaces; and shower spaces. 108.205... DRILLING UNITS DESIGN AND EQUIPMENT Construction and Arrangement Accommodation Spaces § 108.205 Wash spaces; toilet spaces; and shower spaces. (a) For the purposes of this section— (1) “Private facility” means...

  17. Fifteen-minute consultation: problems in the healthy child-toilet training.

    PubMed

    Jacob, Hannah; Grodzinski, Ben; Fertleman, Caroline

    2016-06-01

    Toilet training is a process that all healthy children go through. It is one of the developmental milestones for which parents most often seek medical help. Despite this, many paediatricians feel unconfident managing children presenting with a toilet training problem. We address some common questions arising when assessing and managing such a child, including identifying rare but important diagnoses not to miss. PMID:26933045

  18. 46 CFR 108.205 - Wash spaces; toilet spaces; and shower spaces.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 4 2011-10-01 2011-10-01 false Wash spaces; toilet spaces; and shower spaces. 108.205... DRILLING UNITS DESIGN AND EQUIPMENT Construction and Arrangement Accommodation Spaces § 108.205 Wash spaces; toilet spaces; and shower spaces. (a) For the purposes of this section— (1) “Private facility” means...

  19. Hygienic quality of faeces treated in urine diverting vermicomposting toilets.

    PubMed

    Lalander, Cecilia H; Hill, Geoffrey B; Vinnerås, Björn

    2013-11-01

    On-site sanitation solutions have gained much interest in recent years. One such solution is the urine diverting vermicomposting toilet (UDVT). This study evaluated the hygienic quality of the composted material in six UDVTs in operation in France. Samples were taken from three sampling positions in each toilet, with increasing distance from the fresh material. The concentration of Salmonella spp., Enterococcus spp., thermotolarent coliforms and coliphages were analysed and plotted against a number of variables. The variables found to have the greatest impact was the pH (for Enterococcus spp. and thermotolarent coliforms (TTC)) and time since last maintenance (coliphages). The pH was found to correlate with the material maturity. The current practise of maintenance can cause recontamination of the stabilised material and increase the risk of regrowth of pathogenic microorganisms. A modification in the maintenance procedure, in which a fourth maturation point is introduced, would eliminate this risk. UDVTs were found to be a good on-site sanitation option as the maintenance requirement is small and the system effectively reduced odour and concentration of pathogen and indicator organisms in human waste while keeping the accumulation of material down to a minimum. If the vermicompost is to be used for crops consumed raw, an additional sanitisation step is recommended. PMID:23932466

  20. Toilet Training Children With Autism and Developmental Delays: An Effective Program for School Settings

    PubMed Central

    Cocchiola, Michael A.; Martino, Gayle M.; Dwyer, Lisa J.; Demezzo, Kelly

    2012-01-01

    Current research literature on toilet training for children with autism or developmental delays focuses on smaller case studies, typically with concentrated clinical support. Limited research exists to support an effective school-based program to teach toileting skills implemented by public school staff. We describe an intervention program to toilet train 5 children with autism or developmental delays who demonstrated no prior success in the home or school setting. Intervention focused on (a) removal of diapers during school hours, (b) scheduled time intervals for bathroom visits, (c) a maximum of 3 min sitting on the toilet, (d) reinforcers delivered immediately contingent on urination in the toilet, and (e) gradually increased time intervals between bathroom visits as each participant met mastery during the preceding, shorter time interval. The program was effective across all 5 cases in a community-based elementary school. Paraprofessional staff implemented the program with minimal clinical oversight. PMID:23730467

  1. Polarity of prismatic facets delimiting WC grains in WC-Co alloys.

    PubMed

    Lay, Sabine; Donnadieu, Patricia; Loubradou, Marc

    2010-07-01

    This study reports a determination of the polarity of WC facets in WC-Co alloys sintered at the liquid state. In these alloys, WC grains are delimited by basal facets and two sets of {10 10} prismatic facets, one set of facets being much more developed than the other. A variation of the shape is observed as a function of the composition of the alloy. High resolution transmission electron microscopy is used to investigate the polarity of the prismatic facets owing to the typical triangular patterns appearing on the images. The effect of the composition is investigated using two alloys with different carbon potentials and one containing VC and Cr(3)C(2) as grain growth inhibitors. The interpretation of the images shows that in all cases, the same set of prismatic planes is favoured. PMID:20206535

  2. Deformation Behaviors of Cold-Sprayed WC-Co Particles

    NASA Astrophysics Data System (ADS)

    Ji, Gang-Chang; Chen, Xiao; Wang, Hong-Tao; Bai, Xiao-Bo; Dong, Zeng-Xiang

    2015-08-01

    In the present work, the WC-Co particles with different sizes and contents of WC particle were deposited on the stainless and WC-Co substrate in different accelerating gas temperatures. The deformation mechanisms of incident WC-Co particles and impacted substrates, and especially their interactions were characterized via scan electron microscopy (SEM) observations of both surface morphologies and cross-sectional microstructures of individual splats, and splat/substrate interface with the assistance of focus ion beam (FIB). The effects of feedstock powder structure, i.e., WC particle size and Co content, and temperature of accelerating gas on plastic deformation were comprehensively studied. It was revealed that the splats on stainless steel exhibited ellipsoid shape with a comparative integrated contour similar to original powder, and there were some revers on substrate around splats. In contrast, splats on WC-Co substrate exhibited more flattened pie shape with some ejectas on its periphery in the radial direction. The more curved interface convex to stainless steel substrate appeared compared to that of WC-Co substrate. Deformation of WC-Co splats was enhanced by the increment of substrate hardness and increment of Co binder and reduction of WC size of incident particles.

  3. Automatic Flushing Toilets: An Entertaining Platform for Exploring Scientific Thinking

    NASA Astrophysics Data System (ADS)

    Blais, Brian S.

    2011-03-01

    It is often challenging, especially at the beginning of a course, to find good examples where students can actively explore and grapple with the methods of science. We want them to learn the connection between observation, theory, prediction, evidence, and falsification, but to really accomplish this we need platforms for which the students are able to design and implement experiments, and we need to be able to see the results of those experiments relatively quickly. There are some nice ideas using games and simple demonstrations and labs.2,3 I have found an example that is both entertaining for the students and rich enough in behavior to be an ideal platform for introducing scientific thinking: the automatic flushing toilet (Fig. 1).

  4. Analysis of Formation and Interfacial WC Dissolution Behavior of WC-Co/Invar Laser-TIG Welded Joints

    NASA Astrophysics Data System (ADS)

    Xu, P. Q.; Ren, J. W.; Zhang, P. L.; Gong, H. Y.; Yang, S. L.

    2013-02-01

    During the valve fabrication, hard metal is welded to stainless steel or invar alloy for sealing purposes because of its good heat resistance operating at 500 °C. However, WC (tungsten carbide) dissolution in weld pool softens the hard metal and decreases mechanical properties near the hard metal/weld interface. In order to analyze the WC dissolution in welded joint, joining of hard metal and invar alloy was carried out using laser-tungsten inert gas hybrid welding method. Microstructures of the weld region, chemical composition were investigated using optical microscope, scanning electron microscopy, and EDAX, respectively. Mechanical properties such as microhardness and four-point bend strength test were performed. Larger and smaller WC dissolution and WC dissolution through transition layer based on thermo-dynamics were discussed. The results thus indicate that WC dissolution led to cellular microstructure, columnar crystal, and transition layer under the effect of laser beam and tungsten arc. WC dissolution was affected by metal ions Fe+, Ni+, Co+ exchange in W-M-C system, and WC grain growth was driven by forces caused by laser beam and tungsten arc in larger WC, smaller WC, and liquid Fe, Ni systems.

  5. Bidet toilet seats with warm-water tanks: residual chlorine, microbial community, and structural analyses.

    PubMed

    Iyo, Toru; Asakura, Keiko; Nakano, Makiko; Yamada, Mutsuko; Omae, Kazuyuki

    2016-02-01

    Despite the reported health-related advantages of the use of warm water in bidets, there are health-related disadvantages associated with the use of these toilet seats, and the bacterial research is sparse. We conducted a survey on the hygienic conditions of 127 warm-water bidet toilet seats in restrooms on a university campus. The spray water from the toilet seats had less residual chlorine than their tap water sources. However, the total viable microbial count was below the water-quality standard for tap water. In addition, the heat of the toilet seats' warm-water tanks caused heterotrophic bacteria in the source tap water to proliferate inside the nozzle pipes and the warm-water tanks. Escherichia coli was detected on the spray nozzles of about 5% of the toilet seats, indicating that the self-cleaning mechanism of the spray nozzles was largely functioning properly. However, Pseudomonas aeruginosa was detected on about 2% of the toilet seats. P. aeruginosa was found to remain for long durations in biofilms that formed inside warm-water tanks. Infection-prevention measures aimed at P. aeruginosa should receive full consideration when managing warm-water bidet toilet seats in hospitals in order to prevent opportunistic infections in intensive care units, hematology wards, and other hospital locations. PMID:26837831

  6. Investigation of toilet activities in elderly patients with dementia from the viewpoint of motivation and self-awareness.

    PubMed

    Uchimoto, Kazuki; Yokoi, Teruo; Yamashita, Teruo; Okamura, Hitoshi

    2013-08-01

    Toilet activities of the elderly patients with dementia were observed focusing on care conditions and investigated based on Hull's drive reduction theory (behavior = drive × habit × incentive) and our self-awareness model (consisting of theory of mind, self-evaluation, and self-consciousness) to evaluate the association between self-awareness and toilet activities in patients with dementia and to explain the time when and the reason why a series of toilet activities as habit once acquired become unfeasible. If theory of mind is lost, awareness of one's desire and intention becomes vague, and toilet activities begin to collapse. Furthermore, if incentive disappears, one's intention hardly arises and toilet activities further collapse. If self-evaluation is lost, time sense fades, future goals based on the present time cannot exist, and behavior loses directivity. As a result, toilet activities collapse, and with a decrease in drive toilet activities cease. PMID:23925266

  7. WC-Co Composite Coating Deposited by Cold Spraying of a Core-Shell-Structured WC-Co Powder

    NASA Astrophysics Data System (ADS)

    Luo, Xiao-Tao; Li, Cheng-Xin; Shang, Fu-Lin; Yang, Guan-Jun; Wang, Yu-Yue; Li, Chang-Jiu

    2015-01-01

    In this study, a core-shell-structured WC-Co powder was used to develop a heterogeneously structured WC-Co coating with tens micrometers of WC-10Co as strengthening phase and Co-rich WC-Co as the binder in order to realize simultaneous strengthening and toughening. Spray powder particles contain WC-10Co core coated with a Co-rich WC-Co shell by mechanical milling. WC-Co coating with dual-scale strengthening phases was deposited by cold spraying. Post-spray annealing was carried out to further modify the coating microstructure. Microstructures of the spray powder and the coating were characterized by SEM. Mechanical properties of the coating in terms of microhardness and fracture toughness were examined. Results show that a biomodal WC-Co coating with a porosity of only 0.7% was deposited by cold spray. The Co-rich matrix phase contains submicrometer-sized carbide and primary hard phase is WC-10Co particles. The measurement yielded a Vickers microhardness of 1493 ± 76.7 HV0.1 for WC-10Co core and 693 ± 47.3 HV0.1 for Co-rich binder phase. After annealed at 900 °C for 5 h, a remarkable increase in fracture toughness from 21.2 ± 3.8 to 35.7±5.2 MPa m-0.5 was achieved while no evident change occurred to the hardness of WC-10Co cores.

  8. Ni-WC/C nanocluster catalysts for urea electrooxidation

    NASA Astrophysics Data System (ADS)

    Wang, Lu; Li, Mingtao; Huang, Zhiyu; Li, Yingming; Qi, Suitao; Yi, Chunhai; Yang, Bolun

    2014-10-01

    A nanocluster Ni-WC/C electrocatalyst is prepared through a sequential impregnation method and is used for the urea electrooxidation in alkaline conditions. The micro-morphology, lattice parameter, composition and surface states of Ni-WC/C particles are determined by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), energy dispersive X-ray (EDX) and X-ray photoelectron spectrometry (XPS) analysis. The electrooxidation activity and stability of the Ni-WC/C catalyst are also investigated by cyclic voltammograms and chronoamperograms. Characterization results indicate that the Ni nanoclusters are uniformly distributed on the WC/C framework, and the Ni-WC/C catalyst shows high electrocatalytic activity and stability for urea electrooxidation. The maximum current density at the Ni-WC/C electrode is almost 700 mA cm-2 mg-1 which is one order of magnitude higher than that at the Ni/C electrode, and the steady current density at the Ni-WC/C electrode is also markedly improved. Furthermore, the ESA values and XPS spectra indicate that the enhanced performance of the Ni-WC/C catalyst could be attributed to the structure effect and electron effect between nickel and tungsten carbide.

  9. Corrosion behavior of rare earth modified WC-12Co coating

    NASA Astrophysics Data System (ADS)

    Liu, Yan; Chen, Hui; Ceng, Shengbo; Gou, Guoqing; Tu, Mingjing

    2015-03-01

    Rare earth has been widely used in materials manufacturing to improve hardness and toughness. In this paper, conventional, nano-modified and CeO2 modified WC-12Co coatings are produced by using high speed oxygen flaming (HVOF) spraying technology. Long-term immersion and electrochemical tests of these coatings in 3.5 wt.% NaCl solution are conducted. The surface morphologies were observed to investigate the corrosion mechanisms. The results show CeO2 modified WC-12Co coatings to possess the best corrosion resistance but the nano-modified WC-12Co coating has the worst performance. Results suggest that the improvement of corrosion resistance for CeO2 modified WC-12Co coating can be attributed to the enhancement of interfacial strength between Co binder phase and WC particles.

  10. Variable-Volume Flushing (V-VF) device for water conservation in toilets

    NASA Technical Reports Server (NTRS)

    Jasper, Louis J., Jr.

    1993-01-01

    Thirty five percent of residential indoor water used is flushed down the toilet. Five out of six flushes are for liquid waste only, which requires only a fraction of the water needed for solid waste. Designers of current low-flush toilets (3.5-gal. flush) and ultra-low-flush toilets (1.5-gal. flush) did not consider the vastly reduced amount of water needed to flush liquid waste versus solid waste. Consequently, these toilets are less practical than desired and can be improved upon for water conservation. This paper describes a variable-volume flushing (V-VF) device that is more reliable than the currently used flushing devices (it will not leak), is simple, more economical, and more water conserving (allowing one to choose the amount of water to use for flushing solid and liquid waste).

  11. 21 CFR 1250.38 - Toilet and lavatory facilities for use of food-handling employees.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... directing food-handling employees to wash their hands after each use of toilet facilities shall be posted so as to be readily observable by such employees. Hand washing facilities shall include soap,...

  12. 21 CFR 1250.38 - Toilet and lavatory facilities for use of food-handling employees.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... directing food-handling employees to wash their hands after each use of toilet facilities shall be posted so as to be readily observable by such employees. Hand washing facilities shall include soap,...

  13. Crouching over the toilet seat: prevalence among British gynaecological outpatients and its effect upon micturition.

    PubMed

    Moore, K H; Richmond, D H; Sutherst, J R; Imrie, A H; Hutton, J L

    1991-06-01

    This study investigated whether British women prefer to crouch over public toilet seats, and measured the effect of such a voiding position on urine flow rate and residual urine volume. Of 528 consecutive women who attended a general gynaecological clinic and completed an anonymous questionnaire, 85% usually crouched over the toilet when using a public convenience, 12% applied paper to the seat and 2% sat directly on public toilet seats. When using a friend's bathroom 38% of the women voided by crouching. Results were similar for 155 patients attending a urodynamic clinic, 80 of whom were studied while voiding in both positions. There was a 21% reduction in average urine flow rate and a 149% increase in residual urine volume in the crouching position. Women undergoing urodynamic tests should be asked which voiding position they used before abnormal results are interpreted. Patients with a reduced functional bladder capacity may benefit from being encouraged to sit comfortably on the toilet whenever possible. PMID:1873247

  14. Composting toilets as a sustainable alternative to urban sanitation – A review

    SciTech Connect

    Anand, Chirjiv K. Apul, Defne S.

    2014-02-15

    Highlights: • Composting toilets can be an alternative to flush based sanitation. • Many different composting toilet designs are available. • Composting is affected by moisture content, temperature, carbon to nitrogen ratio. • There are many barriers to composting toilets. • Research is needed in science based design of composting toilets. - Abstract: In today’s flush based urban sanitation systems, toilets are connected to both the centralized water and wastewater infrastructures. This approach is not a sustainable use of our water and energy resources. In addition, in the U.S., there is a shortfall in funding for maintenance and upgrade of the water and wastewater infrastructures. The goal of this paper was to review the current knowledge on composting toilets since this technology is decentralized, requires no water, creates a value product (fertilizer) and can possibly reduce the burden on the current infrastructure as a sustainable sanitation approach. We found a large variety of composting toilet designs and categorized the different types of toilets as being self contained or central; single or multi chamber; waterless or with water/foam flush, electric or non-electric, and no-mix or combined collection. Factors reported as affecting the composting process and their optimum values were identified as; aeration, moisture content (50–60%), temperature (40–65 °C), carbon to nitrogen ratio (25–35), pH (5.5–8.0), and porosity (35–50%). Mass and energy balance models have been created for the composting process. However there is a literature gap in the use of this knowledge in design and operation of composting toilets. To evaluate the stability and safety of compost for use as fertilizer, various methods are available and the temperature–time criterion approach is the most common one used. There are many barriers to the use of composting toilets in urban settings including public acceptance, regulations, and lack of knowledge and

  15. Understanding the prevalence of inpatient falls associated with toileting in adult acute care settings.

    PubMed

    Tzeng, Huey-Ming

    2010-01-01

    This qualitative study determined the prevalence of inpatient falls that were associated with toileting in a Michigan community hospital. Of all falls, 45.2% were related to toileting. The most common theme was falling on the way from the bed or chair to the bathroom. Nurses should focus on safe patient transfers and on using the completed risk assessment and should develop an individualized prevention plan for each patient based on their needs. PMID:19553863

  16. Solid-Particle Erosion Behaviour of WC/Ni Composite Clad layers with Different Contents of WC Particles

    NASA Astrophysics Data System (ADS)

    Paul, C. P.; Mishra, S. K.; Tiwari, P.; Kukreja, L. M.

    2013-09-01

    We investigated the solid particle erosion behaviour of WC-reinforced Ni-matrix based laser clad layers to improve the performance of engineering components for potential power plant applications. WC-reinforced Ni-matrix based laser clad layers having various compositions of WC (5, 10 and 15wt%) were deposited on austenitic stainless steel substrates. The laser clad layers were characterised using optical and scanning electron microscopy, microhardness testing and air-jet erosion testing. In solid particle erosion studies using the air-jet erosion tester, the set of testing parameters, including air-erodent compositions, erodent particle velocities and impact angles, was selected by using the Taguchi technique. The morphologies of the worn surfaces were used to predict the wear mechanisms. The results of a microstructural examination of the cross-sections of laser clad revealed a good metallurgical bond between the WC-reinforced Ni matrix and the austenitic stainless steel substrate. Dissociation/partial melting/full melting of WC particles was not observed in the laser clad layers. The microhardness value in the laser cladding zone was between 900-2400 VHN, while it was 230-270 VHN on the substrate. The results of erosion wear studies of the WC-Ni laser clad surface revealed that the erosion behaviour of the WC-Ni laser clad is primarily governed by erodent jet velocity followed by impact angle. The erosion does not much depend on the Ni-concentration in the MMC or the erodent feed rate. The wear signature at the erosion wear surface indicated that the erosion was primarily governed by a ductile erosion mechanism followed by the removal of WC particles from the matrix. The erosion resistance of the Ni-clad layer with WC was found to be at least four times higher than that without WC particles. The quantified contribution of various erosion parameters is useful for function-based design of components with extended service life.

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

    SciTech Connect

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

    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.

  18. Effects of WC phase contents on the microstructure, mechanical properties and tribological behaviors of WC/a-C superlattice coatings

    NASA Astrophysics Data System (ADS)

    Pu, Jibin; He, Dongqing; Wang, Liping

    2015-12-01

    Nanocomposite WC/a-C coatings with variable contents of tungsten carbide (WC1-x) and amorphous carbon (a-C) were successfully fabricated using a magnetron sputtering process. The microstructure, mechanical properties and tribological behaviors of the as-fabricated coatings were investigated and compared. The results showed that the "superlattice coating" feature of an alternating multilayer structure with a-C and WC1-x nanocrystallites layers on the nanoscale was formed. These multilayer superlattice structures led to diminished residual stress and improved the strength of the adhesion to the substrate. The WC/a-C coating with W 5.43 at.% exhibited low friction coefficients of 0.05 at 25 °C and 0.28 at 200 °C. This significant improvement in the tribological performances of the WC/a-C coating was mainly attributed to the superior "superlattice" microstructure and the formation of a continuously compacted tribofilms, which was rich in graphitized carbon at 25 °C and dominated by the friction triggered WO3 at 200 °C. Moreover, the WC/a-C coating with W 5.43 at.% achieved optimal anti-wear properties at 25 °C due to the synergistic combination of the enhancement effects of the WC1-x nanoparticles and the partition effect from the transfer film that restricted direct contact of the steel ball with the coating and thus prevented further intense wear. The accelerated wear of the WC/a-C coating with the increase of the WC phase content at 200 °C might be due to the combination of oxidation wear and abrasive wear that originated from the WC1-x phase.

  19. Differences in toileting habits between children with chronic encopresis, asymptomatic siblings, and asymptomatic nonsiblings.

    PubMed

    Borowitz, S M; Cox, D J; Sutphen, J L

    1999-06-01

    No studies have compared toileting-specific behaviors of encopretic children with those of asymptomatic children and have controlled for environmental factors such as parental attitudes, parenting styles, and bathroom facilities. This study prospectively examined the toileting habits of 86 chronically encopretic children compared with those of 27 asymptomatic siblings and 35 asymptomatic nonsiblings. Although encopretic children experienced significantly more soiling than did controls, the total number of daily bowel movements passed in the toilet (+/-SD) was comparable in the three groups (.92 +/- .76 in encopretic children compared with 1.14 +/- .43 and 1.08 +/- .47 in siblings and nonsiblings, respectively). Encopretic children experienced pain with defecation more often than did controls. During the 14-day study period, encopretic children complained of pain on 2.75 +/- 4.03 days compared with .58 +/- 1.84 days among sibling controls and 2.31 +/- 3.21 days among nonsibling controls. The mean pain score in encopretic children was .76 +/- 1.00 compared with .05 +/- .15 and .26 +/- .38 among siblings and nonsiblings, respectively. All three groups of children sat on the toilet without parental prompting the same number of times each day. In summary, children with chronic encopresis do not seem to avoid toileting, and they exhibit toileting behaviors that are very similar to those of asymptomatic siblings as well as to those of nonsibling controls. PMID:10393070

  20. Characterization of Nanostructured WC-Co Deposited by Cold Spraying

    NASA Astrophysics Data System (ADS)

    Li, Chang-Jiu; Yang, Guan-Jun; Gao, Pei-Hu; Ma, Jian; Wang, Yu-Yue; Li, Cheng-Xin

    2007-12-01

    Nanostructured WC-Co coating was deposited by cold spraying using a nanostructured WC-12Co powder. The critical velocity for the particle to deposit was measured. The coating microstructure was characterized by X-ray diffraction analysis, scanning electron microscopy, and transmission electron microscopy. The coating hardness was tested using a Vickers hardness tester. The deposition behavior of single WC-Co particle was examined. WC particle size was measured for comparison of deposit properties to that of sintered bulk. The result shows that the nanostructured WC-Co coating can be successfully deposited by cold spraying using nanostructured powders. The coating exhibited a dense microstructure with full retention of the original nanostructure in the powder to the coating. The test of microhardness of the coating yielded a value of over 1820 Hv0.3, which is comparable to that of sintered nanostructured WC-Co. The deposition behavior of WC-Co powders as superhard cermet materials in cold spraying and powder structure effects is discussed.

  1. Hybrid Co-Cr/W-WC and Ni-W-Cr-B/W-WC Coating Systems

    NASA Astrophysics Data System (ADS)

    Vernhes, L.; Azzi, M.; Bousser, E.; Schmitt, T.; Lamarre, J. M.; Klemberg-Sapieha, J. E.

    2016-01-01

    The aim of this study was to investigate the effects of subsurface materials on the performance of a wear-resistant thin film. The mechanical, tribological, and corrosion properties were assessed for two hybrid coating systems: (1) W-WC thin film and a laser cladded Co-Cr interlayer applied to a 316 stainless steel substrate and (2) the same W-WC thin film and a spray-and-fused Ni-W-Cr-B interlayer applied to an Inconel® 718 substrate. They were then compared to the same systems without an interlayer. The microstructures were analyzed by XRD, EDS, and SEM. The hardness and surface load-carrying capacity of the coating systems were determined by micro- and macrohardness testing. Rockwell indentation was used to assess coating adhesion (CEN/TS 1071-8). Tribological properties were assessed with a reciprocating tribometer, and corrosion resistance was determined by potentiodynamic polarization and electrochemical impedance spectroscopy. The originality of this work lies in the finding that, except for the Inconel 718/Ni-W-Cr-B/W-WC system, the wear rate decreases with decreasing hardness of the subsurface materials carrying the thin film due to the decreasing contact pressure for a given load. Another novel finding is the stress-induced phase transformation of the Co-Cr interlayer, which occurs beneath the thin film under high load.

  2. Atom probe tomography analysis of WC powder.

    PubMed

    Weidow, Jonathan

    2013-09-01

    A tantalum doped tungsten carbide powder, (W,Ta)C, was prepared with the purpose to maximise the amount of Ta in the hexagonal mixed crystal carbide. Atom probe tomography (APT) was considered to be the best technique to quantitatively measure the amount of Ta within this carbide. As the carbide powder consisted in the form of very small particles (<1 μm), a method to produce APT specimens of such a powder was developed. The powder was at first embedded in copper and a FIB-SEM workstation was used to make an in-situ lift-out from a selected powder particle. The powder particle was then deposited on a post made from a WC-Co based cemented carbide specimen. With the use of a laser assisted atom probe, it was shown that the method is working and the Ta content of the (W,Ta)C could be measured quantitatively. PMID:23507029

  3. The Toileting Habit Profile Questionnaire: Screening for Sensory-Based Toileting Difficulties in Young Children with Constipation and Retentive Fecal Incontinence

    ERIC Educational Resources Information Center

    Beaudry-Bellefeuille, Isabelle; Lane, Shelly J.; Ramos-Polo, Eduardo

    2016-01-01

    This study examined the face and preliminary content validity of the Toileting Habit Profile Questionnaire, a tool designed to screen for sensory-based defecation difficulties in children. A panel of experts reviewed a pilot version of the questionnaire and responded to probe questions. Two reviewers conducted direct content analysis of responses;…

  4. Composting toilets as a sustainable alternative to urban sanitation--a review.

    PubMed

    Anand, Chirjiv K; Apul, Defne S

    2014-02-01

    In today's flush based urban sanitation systems, toilets are connected to both the centralized water and wastewater infrastructures. This approach is not a sustainable use of our water and energy resources. In addition, in the U.S., there is a shortfall in funding for maintenance and upgrade of the water and wastewater infrastructures. The goal of this paper was to review the current knowledge on composting toilets since this technology is decentralized, requires no water, creates a value product (fertilizer) and can possibly reduce the burden on the current infrastructure as a sustainable sanitation approach. We found a large variety of composting toilet designs and categorized the different types of toilets as being self contained or central; single or multi chamber; waterless or with water/foam flush, electric or non-electric, and no-mix or combined collection. Factors reported as affecting the composting process and their optimum values were identified as; aeration, moisture content (50-60%), temperature (40-65°C), carbon to nitrogen ratio (25-35), pH (5.5-8.0), and porosity (35-50%). Mass and energy balance models have been created for the composting process. However there is a literature gap in the use of this knowledge in design and operation of composting toilets. To evaluate the stability and safety of compost for use as fertilizer, various methods are available and the temperature-time criterion approach is the most common one used. There are many barriers to the use of composting toilets in urban settings including public acceptance, regulations, and lack of knowledge and experience in composting toilet design and operation and program operation. PMID:24268916

  5. Sliding wear behavior of nanostructured WC-Co-Cr coatings

    NASA Astrophysics Data System (ADS)

    Wang, Haibin; Wang, Xuezheng; Song, Xiaoyan; Liu, Xuemei; Liu, Xingwei

    2015-11-01

    The nanostructured WC-10Co-4Cr coatings were fabricated by high velocity oxy-fuel spraying using the in situ synthesized WC-Co nanocomposite powder with size of 70-200 nm and Cr addition. Through optimization of the processing conditions, the nanostructured WC-Co-Cr coating has only a small amount of decarburized phase, a dense microstructure and an excellent combination of hardness, fracture toughness and wear resistance. A series of sliding wear tests were performed to investigate the wear behavior of the nanostructured cermet coating. The evolution of the friction coefficient, wear characteristics and their mechanisms were studied for the nanostructured WC-Co-Cr coating with the change of the load. The present study proposes a new understanding of the occurrence and the related mechanisms of the wear of the cermet coatings.

  6. Toilet training in daycare centers in Flanders, Belgium.

    PubMed

    Kaerts, Nore; Van Hal, Guido; Vermandel, Alexandra; Wyndaele, Jean-Jacques

    2012-06-01

    Several changes have occurred in the toilet training (TT) process in recent decades. There has been an increase in the use of daycare as both parents now often work outside the home. Most children attend daycare centers during the period TT usually takes place, and daytime training has shifted from home to daycare. This study is the first to evaluate the way TT is done in daycare centers. A questionnaire was sent to 1,500 daycare centers, of which 429 replied (response rate of 28.6%). The results show that half of the childcare workers base the decision to start TT on readiness signs. The combination of age and readiness signs is used by 44.5%. The majority of the respondents spent more than 1 h per day on TT (81.8%); 79.8% considered that daycare and parents should play an equal role in TT. However, more than a third of the respondents thought that parents pass the responsibility for TT on to daycare and that not enough attention was paid to TT in the home. Most respondents stated that daycare centers had the facilities and means to be able to give the children proper TT (88.5%). Other research indicated that the outcome of TT is not that good overall and that there is room for improvement in the methods used. More research is needed on the role division and on the interaction between daycare and parents and their combined influence on the process and outcome of TT. PMID:22207492

  7. Completion report for the isolation and remediation of inactive liquid low-level radioactive waste tanks WC-5, WC-6, WC-8, WC-19, 3002-A, 7560, and 7562 at Oak Ridge National Laboratory Oak Ridge, Tennessee

    SciTech Connect

    1997-12-01

    The Federal Facility Agreement (FFA) between the U.S. Environmental Protection Agency (EPA), Tennessee Department of Environment and Conservation (TDEC), and U.S. Department of Energy (DOE) requires that all liquid low-level waste tanks at Oak Ridge National Laboratory removed from service, designated in the FFA as Category D, be remediated in accordance with Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) requirements. A human health risk screening assessment was conducted for inactive Tanks WC-5, WC-6, WC-8, WC-19, 3002-A, 7560, and 7562 as part of an evaluation to determine the method of remediation necessary to safely and permanently isolate and remediate the tanks. Risk screening assessment results indicated that the health risks associated with these tanks were within or below the EPA range of concern of 1 x 10{sup -4} to 1 x 10{sup -6}. On the basis of these results and with regulators concurrence, it was determined that either no action or in-place stabilization of the tanks would satisfy risk-based remediation goals. Therefore, decisions were made and approved by DOE to remediate these tanks in-place as maintenance actions rather than actions under the CERCLA process. Letters documenting these decisions were approved by DOE and subsequently submitted to TDEC and EPA, who concurred with the maintenance actions. Tanks WC-5, WC-6, WC-8, WC-19, 3002-A, 7560, and 7562 were isolated from associated piping, electrical systems, and instrumentation and were grouted in-place. Tank 7562 was originally isolated from associated piping and instrumentation and left in-place empty for future remedial consideration. Upon further consideration, the decision was made by DOE, with concurrence by the regulators, to complete the maintenance action of Tank 7562 by grouting it in-place in March 1997.

  8. Quantitative and qualitative analysis of urine component in the toilet set using Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Chung, So Hyun; Park, Kwang Suk; Choi, Jong Min; Lee, Won Jin

    2004-07-01

    As a part of non-invasive and unaware measurement of physiological signal in the house of live-alone person, Raman spectroscopy was applied for urine component analysis in the toilet set. 785nm, 250-300mW output solid state diode laser and 2048 element linear silicon TE cooled CCD array were incorporated for this system. Several tests were performed for setting up Raman spectroscopy in non-constrained situation: toilet set in the house. The effect of dark current, integration time, warming up time of laser, property of probe and interference of water in the toilet were tested and controlled for appropriate measurement in this environment. The spectra were obtained immediately when the subject uses the toilet set, and they can be transmitted to the server though Bluetooth. Those spectra were pre-processed for removing or correcting the effect of undesired light scattering, sample path-length difference and baseline-effect. The preprocessed data were enhanced for more exact result of multivariate analysis. The training data was prepared for predicting unknown component and its concentration by using multivariate methods. Several kinds of multivariate methods: PCA, PCR, PLS were performed to validate what is the fittest method in this environment. Through quantitative and qualitative analysis of Raman spectroscopy"s spectra obtained in the house's toilet set, we could know the component and its concentration of urine which can be index of disease.

  9. [Case of dyspnea due to toilet cleaner containing nitric acid for household use].

    PubMed

    Yanagawa, Youichi; Matsukawa, Takehisa; Yokoyama, Kazuhito; Hirano, Yohei; Ri, Tetsunari; Aihara, Koichiro; Iba, Toshiaki; Tanaka, Hiroshi

    2013-09-01

    A 40-year-old male tried to clean a urinal at his home storing 900 mL of a toilet cleaner containing 9.8% nitric acid to remove calcium deposit, and clean the toilet floor for twenty minutes. Immediately after using the cleaner, he experienced eye irritation. He washed out the toilet cleaner. However, he thereafter experienced dyspnea, a compressive sensation in his chest, and chest and back pain about 40 minutes after the cleaning the toilet. He monitored his symptoms overnight and found them to gradually improve. However, the symptoms still remained the next morning and therefore he came to our department on foot. He had no particular past or family history. On arrival, his physiological findings and chest computed tomography scan were negative for any abnormalities. His arterial blood gas analysis revealed a mild abnormality of oxygenation. Observation without any drugs revealed that a complete remission of his symptoms occurred after approximately 4 weeks. Based on the results of the experiments, contact with the mucosal membrane and nitric acid gas produced by any accidentally coexisting metals or contact with moisture, including nitric acid produced by a reaction between CaCO3 and cleaner, may have been the mechanism of occurrence for the symptoms observed in this case. This is the first reported case of nitric acid poisoning due to the use of a toilet cleanser intended for household use. PMID:24224389

  10. Laser Cladding of Ni-WC Layers with Graded WC Content

    NASA Astrophysics Data System (ADS)

    Amado, J. M.; Montero, J.; Tobar, M. J.; Yáñez, A.

    Coating techniques using powder as added material can be adapted for the manufacture of composition gradients if a mixing unit is included in the powder feed system. As for the laser cladding technology, FGM can be obtained if mixing parameters are changed along the process. This work deals with the development of NiCrBSi layers with WC graded composition. The purpose is to obtain longitudinal compositional gradients within distances of millimeters along a laser scan. To accomplish this task, the capabilities and time delays in the feeding system are identified and analyzed. Preliminar tests on single cladding beads show results in reasonable agreement with expectations.

  11. Using prepulse inhibition to detect functional D3 receptor antagonism: effects of WC10 and WC44.

    PubMed

    Weber, Martin; Chang, Wei-Li; Durbin, John P; Park, Paula E; Luedtke, Robert R; Mach, Robert H; Swerdlow, Neal R

    2009-08-01

    Prepulse inhibition of startle (PPI) is an operational measure of sensorimotor gating that is impaired in schizophrenia. Treatment with mixed dopamine D2/D3 antagonists diminishes schizophrenia symptoms, and opposes dopamine agonist-induced PPI deficits in rats. There are reasons to believe that functional D3 receptor antagonists might offer more favorable therapeutic profiles compared to current antipsychotics. However, D3-related drug discovery is hampered by the absence of assays sensitive to D3-mediated (antipsychotic) properties in vivo. Here, we characterized two putative D3-active compounds - WC10 and WC44 - in a PPI-based screening assay, comparing the sensitivity of test compounds to oppose PPI deficits induced by the mixed D1/D2-like agonist apomorphine vs. the preferential D3 agonist pramipexole in rats. WC10, WC44 (0, 1, 3, 10 mg/kg, each), and the preferential D2 antagonist L741,626 (0, 1 mg/kg) were studied, in combination with apomorphine (0, 0.5 mg/kg), or pramipexole (0, 1 mg/kg). L741,626 prevented apomorphine-, but not pramipexole-induced PPI deficits. WC10, but not WC44, prevented apomorphine-induced PPI deficits; both compounds opposed pramipexole-induced PPI deficits, suggesting functional D3 and D1/D2 antagonist profiles for WC10, and functional D3 receptor antagonism for WC44. This assay may be valuable for detecting predominantly D3 vs. D2 receptor-linked mechanisms of action in vivo. PMID:19426754

  12. A computational study of interfaces in WC-Co cemented carbides

    NASA Astrophysics Data System (ADS)

    Petisme, Martin V. G.; Johansson, Sven A. E.; Wahnström, Göran

    2015-06-01

    Interfaces in WC-Co cemented carbides have been investigated using the density functional theory (DFT). Six different model WC/WC grain boundaries are considered, together with the corresponding WC surfaces and WC/Co phase boundaries. The contribution to the grain boundary energies arising from misfit is estimated using an analytical bond order potential (ABOP) and the effect of magnetism is investigated using spinpolarized and non-spinpolarized calculations. A systematic study of adsorption of Co to WC surfaces, Co segregation to WC/WC grain boundaries and Co substitution at WC/Co phase boundaries has been carried out. Adsorption of Co to most WC surfaces is predicted, and result in a monolayer coverage of Co and sometimes a mixed Co/W or Co/W monolayer. The WC surfaces will become prewetted with Co as soon as the atoms become mobile at finite temperatures. Co substitutional segregation is predicted to all model WC/WC grain boundaries in 0.5 monolayer proportion. The segregation of Co to grain boundaries stabilizes the continuous skeleton network of hard WC grains in cemented carbides. Using the obtained interfacial energies, the wetting and the driving force for cobalt grain boundary infiltration are discussed. A dependence on the wetting efficiency on the carbon chemical potential is predicted, which could be an explanation for the better wetting observed experimentally under W-rich conditions.

  13. Design Factors Affecting the Reaction Time for Identifying Toilet Signs: A Preliminary Study.

    PubMed

    Chen, Yi-Lang; Sie, Cai-Cin

    2016-04-01

    This study focused on the manner in which design factors affect the reaction time for identifying toilet signs. Taiwanese university students and staff members (50 men, 50 women; M age = 23.5 year, SD = 5.7) participated in the study. The 36 toilet signs were modified on three factors (six presenting styles, two figure-ground exchanges, and three colors), and the reaction time data of all participants were collected when the signs were presented in a simulation onscreen. Participants were quickest when reading Chinese text, followed by graphics and English texts. The findings also showed that men and women had different reaction times across various design combinations. These findings can serve as a reference for practically designing toilet signs, since design factors can lead to difficulties with comprehension based on reaction time measurements. PMID:27166339

  14. Microbiological hazards of household toilets: droplet production and the fate of residual organisms.

    PubMed

    Gerba, C P; Wallis, C; Melnick, J L

    1975-08-01

    Large numbers of bacteria and viruses when seeded into household toilets were shown to remain in the bowl after flushing, and even continual flushing could not remove a persistent fraction. This was found to be due to the adsorption of the organsims to the porcelain surfaces of the bowl, with gradual elution occuring after each flush. Droplets produced by flushing toilets were found to harbor both bacteria and viruses which had been seeded. The detection of bacteria and firuses falling out onto surfaces in bathrooms after flushing indicated that they remain airborne long enough to settle on surfaces throughout the bathroom. Thus, there is a possibility that a person may acquire an infection from an aerosol produced by a toilet. PMID:169732

  15. Microbiological Hazards of Household Toilets: Droplet Production and the Fate of Residual Organisms

    PubMed Central

    Gerba, Charles P.; Wallis, Craig; Melnick, Joseph L.

    1975-01-01

    Large numbers of bacteria and viruses when seeded into household toilets were shown to remain in the bowl after flushing, and even continual flushing could not remove a persistent fraction. This was found to be due to the adsorption of the organisms to the porcelain surfaces of the bowl, with gradual elution occurring after each flush. Droplets produced by flushing toilets were found to harbor both bacteria and viruses which had been seeded. The detection of bacteria and viruses falling out onto surfaces in bathrooms after flushing indicated that they remain airborne long enough to settle on surface throughout the bathroom. Thus, there is a possibility that a person may acquire an infection from an aerosol produced by a toilet. PMID:169732

  16. Neurospora wc-1 and wc-2: transcription, photoresponses, and the origins of circadian rhythmicity.

    PubMed

    Crosthwaite, S K; Dunlap, J C; Loros, J J

    1997-05-01

    Circadian rhythmicity is universally associated with the ability to perceive light, and the oscillators ("clocks") giving rise to these rhythms, which are feedback loops based on transcription and translation, are reset by light. Although such loops must contain elements of positive and negative regulation, the clock genes analyzed to date-frq in Neurospora and per and tim in Drosophila-are associated only with negative feedback and their biochemical functions are largely inferred. The white collar-1 and white collar-2 genes, both global regulators of photoresponses in Neurospora, encode DNA binding proteins that contain PAS domains and are believed to act as transcriptional activators. Data shown here suggest that wc-1 is a clock-associated gene and wc-2 is a clock component; both play essential roles in the assembly or operation of the Neurospora circadian oscillator. Thus DNA binding and transcriptional activation can now be associated with a clock gene that may provide a positive element in the feedback loop. In addition, similarities between the PAS-domain regions of molecules involved in light perception and circadian rhythmicity in several organisms suggest an evolutionary link between ancient photoreceptor proteins and more modern proteins required for circadian oscillation. PMID:9115195

  17. Use of urine alarms in toilet training children with intellectual and developmental disabilities: A review.

    PubMed

    Levato, Lynne E; Aponte, Courtney A; Wilkins, Jonathan; Travis, Rebekah; Aiello, Rachel; Zanibbi, Katherine; Loring, Whitney A; Butter, Eric; Smith, Tristram; Mruzek, Daniel W

    2016-01-01

    The purpose of this review is to describe and evaluate the existing research on the use of urine alarms in the daytime toilet training of children with intellectual and developmental disabilities (IDD). A systematic literature search yielded 12 studies, many of which were published over a decade ago. The findings suggest that interventions that incorporate the use of urine alarms are promising in the treatment of daytime enuresis for children with IDD; however, more carefully controlled research is needed to confirm these findings and elucidate the precise role urine alarms may play in toileting interventions. Methodological strengths and limitations of the body of research are discussed. PMID:26942703

  18. NASA's Marshall Space Flight Center Saves Water With High-Efficiency Toilet and Urinal Program: Best Management Practice Case Study #6 - Toilets and Urinals (Fact Sheet)

    SciTech Connect

    Not Available

    2011-02-01

    The National Aeronautics and Space Administration's (NASA) Marshall Space Flight Center (MSFC) has a longstanding, successful sustainability program that focuses on energy and water efficiency as well as environmental protection. Because MSFC was built in the 1960s, most of the buildings house outdated, inefficient restroom fixtures. The facility engineering team at MSFC developed an innovative efficiency model for replacing these older toilets and urinals.

  19. Vermicomposting toilets, an alternative to latrine style microbial composting toilets, prove far superior in mass reduction, pathogen destruction, compost quality, and operational cost.

    PubMed

    Hill, Geoffrey B; Baldwin, Susan A

    2012-10-01

    Composting toilets aim to recycle excrement into safe, stable humus. Preceding this, low costs, low risks, and mass reduction should be ensured. Source separating vermicomposting toilets (SSVCs) outperformed mixed latrine microbial composting toilets (MLMCs) in all categories. MLMCs: incurred ten times greater operational costs; created 10x more operator exposure; employed no proven pathogen reduction mechanism since solid end-products averaged 71,000±230,000CFU/g (fecal-origin) Escherichia coli and 24±5% total solids, consistently failed NSF/ANSI Standard 41; failed to reduce volatile solids compared to raw fecal matter; increased total contaminated dry mass by 274%, and produced alkaline end-product (8.0±0.7) high in toxic free ammonia (Solvita® 2.6±1.5). SSVCs have low maintenance costs and risks; adequate worm density for pathogen destruction (0.03±0.04g-worm/g-material); reduced E. coli 200±244CFU/g in neutral (7.4±0.3), stable (60±10% volatile solids), and mature (4±0 Solvita® NH(3)) end-product. PMID:22658870

  20. Nanograined WC-Co Composite Powders by Chemical Vapor Synthesis

    NASA Astrophysics Data System (ADS)

    Ryu, Taegong; Sohn, H. Y.; Han, Gilsoo; Kim, Young-Ugk; Hwang, Kyu Sup; Mena, M.; Fang, Zhigang Z.

    2008-02-01

    Nanograined tungsten carbide (WC) Co composite powders were prepared by a chemical vapor synthesis (CVS) process that has previously been used for preparing the aluminides of titanium and nickel and other metallic and intermetallic powders at the University of Utah. To determine the optimum condition for producing nanograined WC-Co composite powders, the effects of carburization temperature, CH4 to WCl6 ratio, CH4 to H2 ratio, CoCl2 contents, and residence time of WC on the powder composition and particle size were investigated. The reduction and carburization of the vaporized chlorides by CH4-H2 mixtures produced nanograined WC and Co composite powder, which sometimes contained small levels of W2C, W, or the η (Co3W3C) phase. The presence of these incompletely carburized phases can be tolerated because they can be fully carburized during the subsequent sintering process. These phases can also be fully carburized by a separate post-treatment. The products were characterized by using X-ray diffraction (XRD) and a transmission electron microscope (TEM). As a result, nanograined WC-Co composite with the particle size less than 30 nm was obtained.

  1. Impingement Resistance of HVAF WC-Based Coatings

    NASA Astrophysics Data System (ADS)

    Deng, C.; Liu, M.; Wu, C.; Zhou, K.; Song, J.

    2007-12-01

    High-velocity oxygen/air fuel (HVO/AF) WC-17Co and WC-10Co4Cr coatings exhibit great potential in the replacement of electrolytic hard chrome (EHC) plating, and comprehensive properties of such coatings should be superior to those of electrolytic hard chrome plating. The impingement resistance of HVAF WC-based coatings sprayed on 300M ultrahigh-strength steel was studied in this paper. As an important property index, the fracture toughness of HVAF WC-based coatings was measured using the microindentation method at loads of 9.8, 19.6, 24.5, 29.4, and 49.0 N, respectively. The cracks resulting from stress concentration in the microindentation were analyzed. The impingement resistance for two HVAF WC coatings and EHC was evaluated according to the ASTM D 3170 standard, and steel ball free-fall experiment was performed at the height of 0.61, 1.52, 1.83, 2.36, and 2.59 m, respectively. The cracks caused by both impingements were analyzed using scanning electron microscopy (SEM) and optical microscopy (OM) in comparison with the cracks in microindentation test.

  2. Explosive compaction of WC+Co mixture by axisymmetric scheme

    NASA Astrophysics Data System (ADS)

    Buzyurkin, A. E.; Kraus, E. I.; Lukyanov, Ya L.

    2015-11-01

    This paper is devoted to the problem of development and optimization of schemes for explosive compaction of mixtures of solid powder materials with metal bond. For this purpose, experiments were conducted on explosive compaction of mixtures of tungsten carbide (WC) and cobalt (Co) using a simple cylindrical compaction system. In addition, a numerical simulation of shock waves propagation in two-phase porous medium WC+Co was carried out. Based on experimental and numerical studies of shock wave propagation, the optimal modes of explosive compaction of two-phase powder media, representing mixtures of solid powder materials with metal bond, were found. It is shown that the most preferable compaction mode for obtaining a uniform durable compact of a mixture of powders WC+Co with ratio 9:1 by volume in axially symmetric scheme with central mandrel corresponds to the detonation velocity of 4.6 km/s followed by sintering.

  3. Are Three Sheets Enough? Using Toilet Paper to Teach Science and Mathematics

    ERIC Educational Resources Information Center

    Woolverton, Christopher J.; Woolverton, Lyssa N.

    2006-01-01

    Toilet paper (TP) composition and physical characteristics were used to model scientific investigations that combined several "National Science Education Standards." Experiments with TP permitted the integration of TP history, societal change resulting from invention, mathematics (including geometry and statistics), germ theory, and personal…

  4. 30 CFR 71.400 - Bathing facilities; change rooms; sanitary flush toilet facilities.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Bathing facilities; change rooms; sanitary... WORK AREAS OF UNDERGROUND COAL MINES Surface Bathing Facilities, Change Rooms, and Sanitary Flush Toilet Facilities at Surface Coal Mines § 71.400 Bathing facilities; change rooms; sanitary flush...

  5. 30 CFR 71.400 - Bathing facilities; change rooms; sanitary flush toilet facilities.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Bathing facilities; change rooms; sanitary... WORK AREAS OF UNDERGROUND COAL MINES Surface Bathing Facilities, Change Rooms, and Sanitary Flush Toilet Facilities at Surface Coal Mines § 71.400 Bathing facilities; change rooms; sanitary flush...

  6. How Long is my Toilet Roll?--A Simple Exercise in Mathematical Modelling

    ERIC Educational Resources Information Center

    Johnston, Peter R.

    2013-01-01

    The simple question of how much paper is left on my toilet roll is studied from a mathematical modelling perspective. As is typical with applied mathematics, models of increasing complexity are introduced and solved. Solutions produced at each step are compared with the solution from the previous step. This process exposes students to the typical…

  7. 46 CFR 32.40-25 - Washrooms and toilet rooms-T/ALL.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... portion thereof in the crew who do not occupy sleeping accommodations to which private or semi-private facilities are attached. (b) The toilet rooms and washrooms must be located convenient to the sleeping..., except where private or semi-private facilities are provided and washbasins are installed in the...

  8. 46 CFR 32.40-25 - Washrooms and toilet rooms-T/ALL.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... portion thereof in the crew who do not occupy sleeping accommodations to which private or semi-private facilities are attached. (b) The toilet rooms and washrooms must be located convenient to the sleeping..., except where private or semi-private facilities are provided and washbasins are installed in the...

  9. 46 CFR 32.40-25 - Washrooms and toilet rooms-T/ALL.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... portion thereof in the crew who do not occupy sleeping accommodations to which private or semi-private facilities are attached. (b) The toilet rooms and washrooms must be located convenient to the sleeping..., except where private or semi-private facilities are provided and washbasins are installed in the...

  10. 16. 3RD FLOOR, J.M. LEHMANN CO. FIVEROLL TOILET SOAP MILL ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    16. 3RD FLOOR, J.M. LEHMANN CO. FIVE-ROLL TOILET SOAP MILL INSTALLED 1950, TO WEST; BUCKET CONVEYOR AT RIGHT MOVED WASTE FROM 2ND FLOOR SOAP PRESSES TO 5TH FLOOR RE-MANUFACTURE - Colgate & Company Jersey City Plant, Building No. B-14, 54-58 Grand Street, Jersey City, Hudson County, NJ

  11. Investigation of a Reinforcement-Based Toilet Training Procedure for Children with Autism.

    ERIC Educational Resources Information Center

    Cicero, Frank R.; Pfadt, Al

    2002-01-01

    This study evaluated the effectiveness of a reinforcement-based toilet training intervention with three children with autism. Procedures included positive reinforcement, graduated guidance, scheduled practice trials, and forward prompting. All three children reduced urination accidents to zero and learned to request bathroom use spontaneously…

  12. 46 CFR 32.40-25 - Washrooms and toilet rooms-T/ALL.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... portion thereof in the crew who do not occupy sleeping accommodations to which private or semi-private facilities are attached. (b) The toilet rooms and washrooms must be located convenient to the sleeping..., except where private or semi-private facilities are provided and washbasins are installed in the...

  13. Factors Associated with Toileting Disability in Older Adults without Dementia Living in Residential Care Facilities

    PubMed Central

    Talley, Kristine M.C.; Wyman, Jean F.; Bronas, Ulf G.; Olson-Kellogg, Becky J.; McCarthy, Teresa C.; Zhao, Hong

    2014-01-01

    Background Older adults without dementia living in residential care facilities with toileting disability have increased care costs and dependency. Understanding associated factors could guide prevention and management strategies. Objective To identify the prevalence of and factors associated with toileting disability in this population. Methods This was a cross-sectional analysis of the 2010 National Survey of Residential Care Facilities. A subsample (N = 2,395) of adults aged 65 years or older, without dementia, and with the potential to implement behavioral interventions was examined. Associated factors were classified according to the disablement process as pathologies, impairments, functional limitations, coexisting disabilities, intra- and extra-individual factors. Logistic regression models accounting for the stratified two-stage probability sampling design were used to identify factors associated with toileting disability. Results Residents were mostly White women, aged 85 years and older. Prevalence of toileting disability was 15%. Associated factors included: reporting fair or poor health, living in a facility with four or less residents, living in a for-profit facility; having bowel incontinence, urinary incontinence, an increased number of physical impairments, visual and hearing impairments; and needing assistance with bathing, dressing, and transferring. Discussion Multicomponent and multidisciplinary prevention and management efforts should be designed for residents without dementia. Future studies testing the efficacy of prevention efforts are needed and should include treatments for incontinence, physical activity programs targeting impairments with walking, standing, sitting, stooping, reaching, and grasping, and therapy to improve dressing, bathing, and transferring skills. PMID:24589646

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

    PubMed Central

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

    2016-01-01

    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. PMID:27485922

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

    NASA Astrophysics Data System (ADS)

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

    2016-08-01

    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.

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

    NASA Astrophysics Data System (ADS)

    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.

  17. Tribological Properties of WC-Reinforced Ni-Based Coatings Under Different Lubricating Conditions

    NASA Astrophysics Data System (ADS)

    Wang, Xiang; Zhu, Lufa; Zhou, Zhiming; Liu, Gang; Liu, Eryong; Zeng, Zhixiang; Wu, Xuedong

    2015-10-01

    In order to improve the tribological properties of aluminum alloy cylinders and cylinder bore walls, WC-reinforced Ni-WC coatings were deposited on an aluminum substrate by atmospheric plasma spraying. The composition and microstructure of Ni-WC coatings with different WC contents were investigated and the tribological properties were tested under oil lubrication, lean oil lubrication and dry friction. The results showed that Ni-WC coatings consisted of a lamellar structure. Friction and wear testing results demonstrated that Ni-WC coatings had much better tribological performance than gray cast iron under different lubricating conditions. These Ni-WC composite coatings exhibited excellent mechanical properties and tribological properties due to the strengthening effect of the WC phase.

  18. Study of W/WC Coatings Varying the Substrate Temperature

    NASA Astrophysics Data System (ADS)

    Ospina, R.; Restrepo, E.; Arango, Y. C.; Castillo, H.; Devia, A.

    2006-12-01

    Tungsten carbide is considered a very important material used for industrial applications due to their high hardness. In this work the production of W/WC coatings used a repetitive pulsed arc system is employed. During the grown process, the substrate temperature is varied in order to identify the influence of this parameter in the structure, composition and morphology of the coatings. The layer of W is grown to improve the adherence of the WC material on the stainless steel 304. To grown the coatings, it was used a W target in the cathode. The gas of work is methane and as it is knew, to use a gas as precursor for WC production causes the apparition of different phases as WC and W2C. The power supply allows varying the active and passive time of pulses, which in this case have a value of 1 s. the coatings produced are characterized by X-ray diffraction (XRD), X-photoelectron spectroscopy (XPS) and scanning probe microscopy (SPM). All of these techniques allow determining properties such as chemical composition, structure, stoichiometry, thickness and grain size.

  19. Atomic layer deposition synthesis and evaluation of core–shell Pt-WC electrocatalysts

    SciTech Connect

    Hsu, Irene J.; Chen, Jingguang G. E-mail: bgwillis@engr.uconn.edu; Jiang, Xiaoqiang; Willis, Brian G. E-mail: bgwillis@engr.uconn.edu

    2015-01-15

    Pt-WC core shell particles were produced using atomic layer deposition (ALD) to deposit Pt layers onto WC particle substrates. A range of Pt depositions were used to determine the growth mechanism for the Pt-WC powder system. TEM imaging and Cu stripping voltammetry found that Pt ALD growth on WC powder substrates was similar to that on WC thin films. However, excess free carbon was found to affect Pt ALD by blocking adsorption sites on WC. The Pt-WC samples were evaluated for the oxygen reduction reaction using a rotating disk electrode to obtain quantitative activity information. The mass and specific activities for the 30 and 50 ALD cycle samples were found to be comparable to a 10 wt. % Pt/C catalyst. However, higher overpotentials and lower limiting currents were observed with ALD Pt-WC compared to Pt/C catalysts, indicating that the oxygen reduction mechanism is not as efficient on Pt-WC as on bulk Pt. Additionally, these Pt-WC catalysts were used to demonstrate hydrogen evolution reaction activity and were found to perform as well as bulk Pt catalyst but with a fraction of the Pt loading, in agreement with the previous work on Pt-WC thin film catalysts.

  20. Gene number determination and genetic polymorphism of the gamma delta T cell co-receptor WC1 genes

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Background WC1 co-receptors belong to the scavenger receptor cysteine-rich superfamily and are encoded by a multi-gene family. Expression of particular WC1 genes defines functional subpopulations of WC1+ '' T cells. Our previous study identified partial sequences for 13 different WC1 genes by annota...

  1. Reactivity in Rapidly Collected Hygiene and Toilet Spot Check Measurements: A Cautionary Note for Longitudinal Studies

    PubMed Central

    Arnold, Benjamin F.; Khush, Ranjiv S.; Ramaswamy, Padmavathi; Rajkumar, Paramasivan; Durairaj, Natesan; Ramaprabha, Prabhakar; Balakrishnan, Kalpana; Colford Jr., John M.

    2015-01-01

    Discreet collection of spot check observations to measure household hygiene conditions is a common measurement technique in epidemiologic studies of hygiene in low-income countries. The objective of this study was to determine whether the collection of spot check observations in longitudinal studies could itself induce reactivity (i.e., change participant behavior). We analyzed data from a 12-month prospective cohort study in rural Tamil Nadu, India that was conducted in the absence of any hygiene or toilet promotion activities. Our data included hygiene and toilet spot checks from 10,427 household visits. We found substantial evidence of participant reactivity to spot check observations of hygiene practices that were easy to modify on short notice. For example, soap observed at the household's primary handwashing location increased from 49% at enrollment to 81% by the fourth visit and remained at or above 77% for the remainder of the study. PMID:25385856

  2. Proposal for a zero-gravity toilet facility for the space station

    NASA Technical Reports Server (NTRS)

    Fleri, Edgar L., Jr.; Galliano, Paul A.; Harrison, Mark E.; Johnson, William B.; Meyer, Gregory J.

    1989-01-01

    This proposed toilet facility has a straightforward design. It has few moving parts and is easily maintained. Air and water flow provide sanitary movement of the waste. The toilet's chambers are coated with Teflon which, along with the water flow, makes it self-cleaning. An added disinfectant called Betadiene kills any bacteria that may form on the chamber walls. The chair is contoured to take into account the neutral body position and the necessary strain position for defecation. Restraints at the ankles, knees, and midsection hold the body in the chair. The waste is stored in discs of Gortex material which are inside a replaceable storage chamber. This chamber can be removed, capped and stored until eventual return to earth.

  3. NASA's Marshall Space Flight Center Saves Water With High-Efficiency Toilet and Urinal Program

    SciTech Connect

    2011-02-22

    The National Aeronautics and Space Administration’s (NASA) Marshall Space Flight Center (MSFC) has a longstanding, successful sustainability program that focuses on energy and water efficiency as well as environmental protection. Because MSFC was built in the 1960s, most of the buildings house outdated, inefficient restroom fixtures. The facility engineering team at MSFC developed an innovative efficiency model for replacing these older toilets and urinals.

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

    NASA Astrophysics Data System (ADS)

    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.

  5. Health risk assessment of exposure to organic matter from the use of reclaimed water in toilets.

    PubMed

    Niu, Zhi-Guang; Zang, Xue; Zhang, Jian-Guo

    2014-05-01

    To estimate the carcinogenic and non-carcinogenic risks of six volatile organic compounds (VOCs) found in reclaimed water used for flushing toilets, a probabilistic health risk assessment based on Monte Carlo simulations was used. Before Monte Carlo simulations, the contaminant volatilization model was applied to estimate the concentration of the pollutants in air. Moreover, a questionnaire was used to acquire daily exposure time and the Batch Fit tool of Crystal Ball software was applied to find the best-fitting distribution of a part of the input parameters. The risk analysis indicated that the health risks from six VOCs were lower than the negligible risk level (1 × 10(-8)) in all cases, and the health risk for females was slightly higher than that for males. Overall, exposure to organic pollutants in reclaimed water during toilet flushing does not currently pose a significant carcinogenic risk to humans. In this study, we want to provide some information on the health risk from reclaimed water used for toilet flushing in China and hope that it will be useful to promote the application of reclaimed water in water-deficient areas. PMID:24510531

  6. Identification and sequence analysis of pWcMBF8-1, a bacteriocin-encoding plasmid from the lactic acid bacterium Weissella confusa.

    PubMed

    Malik, Amarila; Sumayyah, Sumayyah; Yeh, Chia-Wen; Heng, Nicholas C K

    2016-04-01

    Members of the Gram-positive lactic acid bacteria (LAB) are well-known for their beneficial properties as starter cultures and probiotics. Many LAB species produce ribosomally synthesized proteinaceous antibiotics (bacteriocins). Weissella confusa MBF8-1 is a strain isolated from a fermented soybean product that not only produces useful exopolysaccharides but also exhibits bacteriocin activity, which we call weissellicin MBF. Here, we show that bacteriocin production by W. confusa MBF8-1 is specified by a large plasmid, pWcMBF8-1. Plasmid pWcMBF8-1 (GenBank accession number KR350502), which was identified from the W. confusa MBF8-1 draft genome sequence, is 17 643 bp in length with a G + C content of 34.8% and contains 25 open reading frames (ORFs). Six ORFs constitute the weissellicin MBF locus, encoding three putative double-glycine-motif peptides (Bac1, Bac2, Bac3), an ABC transporter complex (BacTE) and a putative immunity protein (BacI). Two ORFs encode plasmid partitioning and mobilization proteins, suggesting that pWcMBF8-1 is transferable to other hosts. To the best of our knowledge, plasmid pWcMBF8-1 not only represents the first large Weissella plasmid to be sequenced but also the first to be associated with bacteriocin production in W. confusa. PMID:26976853

  7. Tungsten Carbide Grain Size Computation for WC-Co Dissimilar Welds

    NASA Astrophysics Data System (ADS)

    Zhou, Dongran; Cui, Haichao; Xu, Peiquan; Lu, Fenggui

    2016-05-01

    A "two-step" image processing method based on electron backscatter diffraction in scanning electron microscopy was used to compute the tungsten carbide (WC) grain size distribution for tungsten inert gas (TIG) welds and laser welds. Twenty-four images were collected on randomly set fields per sample located at the top, middle, and bottom of a cross-sectional micrograph. Each field contained 500 to 1500 WC grains. The images were recognized through clustering-based image segmentation and WC grain growth recognition. According to the WC grain size computation and experiments, a simple WC-WC interaction model was developed to explain the WC dissolution, grain growth, and aggregation in welded joints. The WC-WC interaction and blunt corners were characterized using scanning and transmission electron microscopy. The WC grain size distribution and the effects of heat input E on grain size distribution for the laser samples were discussed. The results indicate that (1) the grain size distribution follows a Gaussian distribution. Grain sizes at the top of the weld were larger than those near the middle and weld root because of power attenuation. (2) Significant WC grain growth occurred during welding as observed in the as-welded micrographs. The average grain size was 11.47 μm in the TIG samples, which was much larger than that in base metal 1 (BM1 2.13 μm). The grain size distribution curves for the TIG samples revealed a broad particle size distribution without fine grains. The average grain size (1.59 μm) in laser samples was larger than that in base metal 2 (BM2 1.01 μm). (3) WC-WC interaction exhibited complex plane, edge, and blunt corner characteristics during grain growth. A WC ( { 1 {bar{{1}}}00} ) to WC ( {0 1 1 {bar{{0}}}} ) edge disappeared and became a blunt plane WC ( { 10 1 {bar{{0}}}} ) , several grains with two- or three-sided planes and edges disappeared into a multi-edge, and a WC-WC merged.

  8. Tungsten Carbide Grain Size Computation for WC-Co Dissimilar Welds

    NASA Astrophysics Data System (ADS)

    Zhou, Dongran; Cui, Haichao; Xu, Peiquan; Lu, Fenggui

    2016-06-01

    A "two-step" image processing method based on electron backscatter diffraction in scanning electron microscopy was used to compute the tungsten carbide (WC) grain size distribution for tungsten inert gas (TIG) welds and laser welds. Twenty-four images were collected on randomly set fields per sample located at the top, middle, and bottom of a cross-sectional micrograph. Each field contained 500 to 1500 WC grains. The images were recognized through clustering-based image segmentation and WC grain growth recognition. According to the WC grain size computation and experiments, a simple WC-WC interaction model was developed to explain the WC dissolution, grain growth, and aggregation in welded joints. The WC-WC interaction and blunt corners were characterized using scanning and transmission electron microscopy. The WC grain size distribution and the effects of heat input E on grain size distribution for the laser samples were discussed. The results indicate that (1) the grain size distribution follows a Gaussian distribution. Grain sizes at the top of the weld were larger than those near the middle and weld root because of power attenuation. (2) Significant WC grain growth occurred during welding as observed in the as-welded micrographs. The average grain size was 11.47 μm in the TIG samples, which was much larger than that in base metal 1 (BM1 2.13 μm). The grain size distribution curves for the TIG samples revealed a broad particle size distribution without fine grains. The average grain size (1.59 μm) in laser samples was larger than that in base metal 2 (BM2 1.01 μm). (3) WC-WC interaction exhibited complex plane, edge, and blunt corner characteristics during grain growth. A WC ( { 1 {bar{{1}}}00} ) to WC ( {0 1 1 {bar{{0}}}} ) edge disappeared and became a blunt plane WC ( { 10 1 {bar{{0}}}} ) , several grains with two- or three-sided planes and edges disappeared into a multi-edge, and a WC-WC merged.

  9. Laser induction hybrid rapid cladding of WC particles reinforced NiCrBSi composite coatings

    NASA Astrophysics Data System (ADS)

    Zhou, Shengfeng; Dai, Xiaoqin

    2010-05-01

    In order to investigate the microstructure characteristics and properties of Ni-based WC composite coatings containing a relatively large amount of WC particles by laser induction hybrid rapid cladding (LIHRC) and compare to the individual laser cladding without preheating, Ni60A + 35 wt.% WC composite coatings are deposited on A3 steel plates by LIHRC and the individual laser cladding without preheating. The composite coating produced by the individual laser cladding without preheating exhibits many cracks and pores, while the smooth composite coating without cracks and pores is obtained by LIHRC. Moreover, the cast WC particles take on the similar dissolution characteristics in Ni60A + 35 wt.% WC composite coatings by LIHRC and the individual laser cladding without preheating. Namely, the completely dissolved WC particles interact with Ni-based alloy solvent to precipitate the blocky and herringbone carbides, while the partially dissolved WC particles still preserve the primary lamellar eutectic structure. A few WC particles are split at the interface of WC and W 2C, and then interact with Ni-based alloy solvent to precipitate the lamellar carbides. Compared with the individual laser cladding without preheating, LIHRC has the relatively lower temperature gradient and the relatively higher laser scanning speed. Therefore, LIHRC can produce the crack-free composite coating with relatively higher microhardness and relatively more homogeneous distribution of WC particles and is successfully applied to strengthen the corrugated roller, showing that LIHRC process has a higher efficiency and good cladding quality.

  10. Influence of Nickel-Coated Nanostructured WC-Co Powders on Microstructural and Tribological Properties of HVOF Coatings

    NASA Astrophysics Data System (ADS)

    Jafari, M.; Enayati, M. H.; Salehi, M.; Nahvi, S. M.; Hosseini, S. N.; Park, C. G.

    2014-12-01

    In this research, a novel nickel-coated nanostructured WC-12Co powder (Ni/nc-WC) was developed and used as feedstock material for high velocity oxygen fuel process. The Ni/nc-WC powders with average WC grain size of ~15 nm were produced by mechanical milling and electroless plating processes. The microstructural and tribological characteristics of Ni/nc-WC coating were investigated and compared with those of microcrystalline WC-12Co (mc-WC) and nanostructured WC-12Co (nc-WC) coatings. X-ray diffractometry, high-resolution field emission scanning electron microscopy, and transmission electron microscopy were used to evaluate the microstructure of the powders and coatings. A ball-on-disk technique was used to probe the wear behavior of the coatings. The Ni/nc-WC coating showed negligible decarburization of ~5.4%, while mc-WC and nc-WC coatings suffered from higher decarburization levels of 16.3 and 36.8%. The wear rate of Ni/nc-WC coating was 2.5 × 10-4 mg/m indicating ~ 75 and 82% increase in wear resistance compared with mc-WC and nc-WC coatings. The wear track analysis of mc-WC and nc-WC coatings showed evidences of delamination mechanism. Besides, a severe carbide pullout mechanism was operative in wear of nc-WC coating. As for Ni/nc-WC coating, individual carbide pullout following the elimination of Ni(Co) matrix was the predominant wear mechanism.

  11. WC-Co/Al Multilayer Coatings by Warm Spray Deposition

    NASA Astrophysics Data System (ADS)

    Watanabe, Makoto; Komatsu, Masayuki; Kuroda, Seiji

    2012-06-01

    WC-Co/aluminum multilayer coatings have been developed by using warm spray deposition to improve fracture toughness and damage tolerance of conventional WC-Co coatings and to investigate the effects of ductile layer addition on their fracture properties. Prior to depositing the multilayer coatings, the mechanical properties of three metal coatings of aluminum, copper, and titanium, which were deposited by warm spraying, were evaluated. The aluminum coating showed excellent ductility among them and was selected for use as ductile layers for the multilayer coatings. The fracture behavior of WC-Co/Al coatings was examined by the four-point bending test. The multilayer coatings did not break in a brittle manner after reaching maximum load, but exhibited a plateau as a result of the ductility of the aluminum layers. The fracture behavior was compared with the finite element analysis results, and they showed good agreement in a general trend. It has been concluded that ductile metal reinforcements, by advanced thermal spray techniques such as warm spray deposition, are very effective to enhance the toughness and damage tolerance of sprayed cermet coatings.

  12. Formation of Hard Surfacing Layers of WC-Co with Electron Beam Cladding Method

    NASA Astrophysics Data System (ADS)

    Abe, Nobuyuki; Morimoto, Junji

    Hard surfacing layers of WC-Co/Ni-base self-fluxing alloy were successfully formed on a steel substrate using an electron beam cladding method. The WC particles were densely and homogenously dispersed within the Ni-base self-fluxing alloy without porosity. The effect of the electron beam conditions on layer formation was investigated, and the cladding layer properties were examined by hardness tests, abrasive wear tests and immersion corrosion tests. It was found that the cladding layers showed higher hardness and abrasion resistance with increasing WC-Co mixing ratio, however, corrosion resistance decreased with WC-Co mixing ratio. A coating layer having high abrasive and corrosion resistance simultaneously was achieved by multiple cladding of high WC-Co mixing ratio layers after low WC-Co mixing ratio layers.

  13. A comparison study of oxygen reduction on the supported Pt, Pd, Au monolayer on WC(0001)

    NASA Astrophysics Data System (ADS)

    Zhang, Xilin; Lu, Zhansheng; Yang, Zongxian

    2016-07-01

    Using the first principles methods, the geometric and electronic structures of the metal monolayers supported on WC(0001) surfaces (MML/WC(0001) (M = Pt, Pd, and Au)) and their catalytic activity toward the oxygen reduction reaction (ORR) were comparatively studied. Both the kinetics and the density of states results demonstrated that the direct dissociation of O2 on all three MML/WC(0001) surfaces are almost impossible. Yet the barriers of the formation and dissociation of OOH on AuML/WC(0001) are much smaller than those on the PtML/WC(0001) and the PdML/WC(0001) surfaces, implying that the AuML/WC(0001) exhibits the highest catalytic activity for ORR via a combination of 2e- hydrogenation of O2 and 4e- dissociation of OOH. The rate-limiting step barrier of 0.83 eV for the hydrogenation of OH forming H2O is also comparable to that on the traditional Pt-based catalysts. The deactivation mechanism of PtML/WC(0001) and the performance of PdML/WC(0001) for ORR were identified. The present study is conductive to designing new efficient catalyst without using of the precious Pt for efficiently promoting ORR.

  14. Cr-rich layer at the WC/Co interface in Cr-doped WC Co cermets: segregation or metastable carbide?

    NASA Astrophysics Data System (ADS)

    Delanoë, A.; Bacia, M.; Pauty, E.; Lay, S.; Allibert, C. H.

    2004-09-01

    The effect of Cr on the microstructure of WC-Co alloys after liquid-phase sintering is studied as a function of the C content of the alloy and for two Cr for Co substitution ratio. The distribution of Cr is investigated using X-ray energy dispersive spectrometry. A Cr enrichment at WC/Co interfaces is detected for both C- and W-rich alloys. The observations by high-resolution electron microscopy point out a thin face centred cubic layer at the interface between WC and Co. This layer has grown epitaxially on the surface of the WC grains with two orientation relationships depending on the WC plane. The lattice parameter mismatch is close to 0.2% for the basal plane and less than 3% for the prismatic plane of WC. The composition and crystal structure of this compound correspond to the metastable (Cr,W)C phase that is stabilized by the low energy of the WC/(Cr,W)C interface.

  15. A child death as a result of physical violence during toilet training.

    PubMed

    Alpaslan, Ahmet Hamdi; Coşkun, Kerem Şenol; Yeşil, Arda; Cobanoğlu, Cansu

    2014-11-01

    Enuresis and delayed bladder control are a common source of psychosocial concern for both parents and children. Different cultures have different norms with regard to parenting attitudes. The fact that in Turkey, parents consider enuresis or encopresis as a sign of laziness, misbehavior, or disobedience rather than a medical disorder may cause children to be exposed to physical and emotional violence and maltreatment by the family as a corrective strategy. We present a case in this paper which had a fatal outcome due to physical violence against a child as an educational measure and a toilet training method. PMID:25440146

  16. Magnetic Properties of the WC-Co Cermet Powders

    NASA Astrophysics Data System (ADS)

    Serban, V. A.; Malaescu, I.; Ercuta, A.; Marin, C. N.; Stefu, N.; Opris, C.; Codrean, C.; Utu, D.

    2010-08-01

    The magnetic behavior, both quasistatic (50 Hz) and dynamic (10 kHz-1 MHz) of a set of three powder samples from the WC-Co cermet system were investigated in the as-cast state. The results have shown magnetic hysteresis in the low frequency AC fields. In high frequency fields, the complex magnetic permeability was examined; a weak maximum of the imaginary component that was detected in the frequency range close to 100 kHz was attributed to structure-dependent magnetic relaxation.

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

    NASA Astrophysics Data System (ADS)

    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.

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

    NASA Astrophysics Data System (ADS)

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

    2016-04-01

    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. Effects of Functional Communication Training (FCT) on the Communicative, Self-Initiated Toileting Behavior for Students with Developmental Disabilities in a School Setting

    ERIC Educational Resources Information Center

    Kim, Jinnie

    2012-01-01

    Far less is known about the effects of functional communication-based toileting interventions for students with developmental disabilities in a school setting. Furthermore, the currently available toileting interventions for students with disabilities include some undesirable procedures such as the use of punishment, unnatural clinic/university…

  20. Suitability of biochar as a matrix for improving the performance of composting toilets.

    PubMed

    Hijikata, Nowaki; Yamauchi, Natsuru; Ishiguro, Masaki; Ushijima, Ken; Funamizu, Naoyuki

    2015-04-01

    To evaluate the suitability of biochar (rice husk charcoal) as a matrix in composting toilets that can decompose human faeces and recover fertiliser components, the composting process during toilet operation and the agricultural value of the resulting compost were characterised by performing a comparison with sawdust, rice husks, and corn stalks. The faecal decomposition ratio in biochar was 42%, similar to the values for rice husks (46%) and corn stalks (41%), but higher than the value for sawdust (25%). Heterotroph micro-organism acidity is qualitatively higher in biochar than in sawdust. However, nitrogen loss in biochar was 19%, lower than that in rice husks (36%) and corn stalks (25%), but similar to that in sawdust (16%). Although the biochar compost had no significant impact on the cation exchange capacity and water retention of sandy soil, the ratio of nitrogen transportation into plants was 12.8%, higher than that for the other materials. These results suggest that biochar is effective for achieving high faecal decomposition, low nitrogen loss, and high nutrient supply. PMID:25739767

  1. Isolation and characterization of an early colonizing Rhizobium sp. R8 from a household toilet bowl.

    PubMed

    Fukano, Toru; Gomi, Mitsuhiro; Osaki, Yukihiko; Morikawa, Masaaki

    2015-01-01

    The bacterial community structure was compared between the third days', one week', and three weeks' biofilm samples from the surface of a household toilet bowl. It was found that the PCR-DGGE band pattern of 16S rRNA gene was dramatically changed after the third day and was not further changed until three weeks. This result suggests that there are early and late colonizing bacterial groups. One of the early colonizers isolated from the third days' sample was Rhizobium sp. R8, a closest relative to Rhizobium giardinii, which exhibited the highest biofilm formation activity in an artificial urine condition. R8 produced extracellular polysaccharides containing galactose, glucose, and mannose at the molar ratio of 8:1:1, which were probably responsible for the biofilm formation. Its excelled biofilm formation and urease activities together with the lack of nodulation and nitrogen fixing genes in R8 suggest that this strain has been specifically adapted to urine condition in a toilet bowl. PMID:25707633

  2. Potential fresh water saving using greywater in toilet flushing in Syria.

    PubMed

    Mourad, Khaldoon A; Berndtsson, Justyna C; Berndtsson, Ronny

    2011-10-01

    Greywater reuse is becoming an increasingly important factor for potable water saving in many countries. Syria is one of the most water scarce countries in the Middle East. However, greywater reuse is still not common in the country. Regulations and standards for greywater reuse are not available. Recently, however, several stakeholders have started to plan for greywater reuse. The main objective of this paper is to evaluate the potential for potable water saving by using greywater for toilet flushing in a typical Syrian city. The Sweida city in the southern part of Syria was chosen for this purpose. Interviews were made in order to reflect the social acceptance, water consumption, and the percentage of different indoor water uses. An artificial wetland (AW) and a commercial bio filter (CBF) were proposed to treat the greywater, and an economic analysis was performed for the treatment system. Results show that using treated greywater for toilet flushing would save about 35% of the drinking water. The economic analyses of the two proposed systems showed that, in the current water tariff, the payback period for AW and CBF in block systems is 7 and 52 years, respectively. However, this period will reduce to 3 and 21 years, respectively, if full water costs are paid by beneficiaries. Hence, introducing artificial wetlands in order to make greywater use efficient appears to be a viable alternative to save potable water. PMID:21621904

  3. Bonding of WC with an iron aluminide (FeAl) intermetallic

    SciTech Connect

    Schneibel, J.H.; Subramanian, R.

    1996-08-01

    FeAl, which has high oxidation and sulfidation resistance, was shown to be thermodynamically compatible with WC. Calculations indicate that soly. of WC in liq. Fe-40at.%Al at 1450 C is about 2 at.%. Since liquid FeAl wets WC very well, the WC/FeAl system lends itself to liquid-phase sintering, resulting in close to theoretical densities. Almost fully dense cermets with 20.6 wt% FeAl binder were produced. With one-step infiltration, 98% dense cermets with only 7 wt% FeAl binder were fabricated. RT bend strengths and fracture toughness for WC-20.6 wt% FeAl reached 1680 MPa and 22 MPa{center_dot}m{sup 1/2}. Ductile binder fracture was observed on the fracture surfaces. Pores containing oxide inclusions were found, suggesting that improvements in processing are likely to further improve the mechanical properties. Insufficient process control may explain why WC/FeAlNi cermets did not show improved mechanical properties, although Ni strengthens FeAl. For WC bonded with FeAl, mechanical properties were measured at RT and 800 C. Bend strengths at 800 C in air increased with WC volume fraction, and fracture toughness were higher than at RT.

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

    NASA Astrophysics Data System (ADS)

    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 <100-nm thickness. The combinational effect of the milling and the plasma in the DBDP milling caused a unique fine flakelike morphology and high-density interfaces in the W-C-10Co powder mixture, which is responsible for the reduced carburization temperature and the nanocomposite structure of WC-Co powder.

  5. Occurrence of tungsten plasma in plasma spraying of WC/Co

    SciTech Connect

    Detering, B.A.; Knibloe, J.R.; Eddy, T.L.

    1990-01-01

    The conditions under which tungsten is vaporized and ionized during plasma spraying of WC/Co powders are investigated spectroscopically. Overheating of the powder results in less cobalt and decarburization of WC in the sprayed coating. The plasma is dominated by ionized tungsten and the resulting coating has a substantial amount of tungsten metal. 15 refs., 4 figs., 2 tabs.

  6. Suspension plasma spraying of nanostructured WC-12Co coatings

    NASA Astrophysics Data System (ADS)

    Berghaus, J. Oberste; Marple, B.; Moreau, C.

    2006-12-01

    Nanostructured WC-12% Co coatings were deposited by suspension plasma spraying of submicron feedstock powders, using an internal injection plasma torch. The liquid carrier used in this approach allows for controlled injection of much finer particles than in conventional thermal spraying, leading to thin coatings with a fine surface finish. A polyethylene-imine (PEI) dispersant was used to stabilize the colloidal suspension in an ethanol carrier. In-flight particle states were measured for a number of operating conditions of varying plasma gas flow rates, feed rates, and standoff distances and were related to the resulting microstructure, phase composition (EDS, SEM, XRD), and Vickers hardness. High in-flight particle velocities (>800 m/s) were generated, leading to dense coatings. It was observed that the coating quality was generally compromised by the high temperature and reactivity of the small particles. To compensate for this shortcoming, the suspension feed rate was adjusted, thereby varying the thermal load on the plasma. Results showed that a slightly larger agglomerate size, in conjunction with low particle jet temperatures, could somewhat limit the decomposition of WC into brittle W2C/W3C and amorphous cobalt containing binder phases.

  7. Microstructure characterization of WC-Ni coatings obtained by HVOF thermal spraying

    SciTech Connect

    Guilemany, J.M.; Nutting, J.; Miguel, J.R.; Dong, Z.

    1995-07-01

    The main purpose of this investigation was to characterize the structure of WC-Ni coatings, which have become of interest in recent years. The WC-Ni powders used in these experiments have been well characterized, but the microstructure of the WC-Ni coating was not well established. In this paper, different techniques, including light optical microscopy, SEM, TEM-STEM, EDS, HRTEM, EPMA, X-ray diffraction, Image analysis and Elemental analysis technique, were used to characterize the WC-Ni coatings. The substrate at the interfacial region also undergoes phase transformations because of the thermal shock from the hot splats. Fine crystal zone, martensite transformation zone and recrystallization zone have been found at different depths of the steel substrate, which is very similar to WC-Co/steel system. These zones have been very well characterized and will be discussed in detail elsewhere.

  8. 30 CFR 71.402 - Minimum requirements for bathing facilities, change rooms, and sanitary flush toilet facilities.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... Rooms, and Sanitary Flush Toilet Facilities at Surface Coal Mines § 71.402 Minimum requirements for... Centers as listed in 45 CFR 5.31. Copies of the National Building Code (1967 edition) may be purchased... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Minimum requirements for bathing...

  9. 30 CFR 71.402 - Minimum requirements for bathing facilities, change rooms, and sanitary flush toilet facilities.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... Rooms, and Sanitary Flush Toilet Facilities at Surface Coal Mines § 71.402 Minimum requirements for... Centers as listed in 45 CFR 5.31. Copies of the National Building Code (1967 edition) may be purchased... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Minimum requirements for bathing...

  10. 30 CFR 71.402 - Minimum requirements for bathing facilities, change rooms, and sanitary flush toilet facilities.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... Rooms, and Sanitary Flush Toilet Facilities at Surface Coal Mines § 71.402 Minimum requirements for... Centers as listed in 45 CFR 5.31. Copies of the National Building Code (1967 edition) may be purchased... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Minimum requirements for bathing...

  11. Parents as Teachers: Teaching Parents How to Teach Toilet Skills to Their Children with Autism and Mental Retardation

    ERIC Educational Resources Information Center

    Ozcan, Nihal; Cavkaytar, Atilla

    2009-01-01

    The purpose of this study was to determine the effectiveness of a parent training program for teaching toilet skills to children with autism and mental retardation. The study was conducted with three mothers and their children. A multiple probe design using probe sessions across subjects was used. The experimental procedure consisted of two…

  12. Performance of UV disinfection and the microbial quality of greywater effluent along a reuse system for toilet flushing.

    PubMed

    Friedler, Eran; Gilboa, Yael

    2010-04-01

    This paper examines the microbial quality of treated RBC (Rotating Biological Contactor) and MBR (Membrane Bioreactor) light greywater along a continuous pilot-scale reuse system for toilet flushing, quantifies the efficiency of UV disinfection unit, and evaluates the regrowth potential of selected microorganisms along the system. The UV disinfection unit was found to be very efficient in reducing faecal coliforms and Staphylococcus aureus. On the other hand, its efficiency of inactivation of HPC (Heterotrophic Plate Count) and Pseudomonas aeruginosa was lower. Some regrowth occurred in the reuse system as a result of HPC regrowth which included opportunistic pathogens such as P. aeruginosa. Although the membrane (UF) of the MBR system removed all bacteria from the greywater, bacteria were observed in the reuse system due to "hopping phenomenon." The microbial quality of the disinfected greywater was found to be equal or even better than the microbial quality of "clean" water in toilet bowls flushed with potable water (and used for excretion). Thus, the added health risk associated with reusing the UV-disinfected greywater for toilet flushing (regarding P. aeruginosa and S. aureus), was found to be insignificant. The UV disinfection unit totally removed (100%) the viral indicator (F-RNA phage, host: E. coli F(amp)(+)) injected to the treatment systems simulating transient viral contamination. To conclude, this work contributes to better design of UV disinfection reactors and provides an insight into the long-term behavior of selected microorganisms along on-site greywater reuse systems for toilet flushing. PMID:20172592

  13. Genotyping of Pseudomonas aeruginosa sputum and stool isolates from cystic fibrosis patients: evidence for intestinal colonization and spreading into toilets.

    PubMed Central

    Döring, G.; Bareth, H.; Gairing, A.; Wolz, C.; Botzenhart, K.

    1989-01-01

    Three hundred and fifty-eight stool and 131 sputum specimens from 40 cystic fibrosis (CF) patients and 100 toilet sinks were investigated for occurrence of Pseudomonas aeruginosa; 67% (21/31) of the patients with chronic P. aeruginosa lung infections carried the organism repeatedly in the stool but the organism was found only once in the stools of nine uninfected patients. P. aeruginosa stool carriage was correlated to high P. aeruginosa numbers in patients' sputa. Typing of P. aeruginosa with a DNA probe showed identity of sputum and stool strains. Seven patients repeatedly carried additional stool strains, not found in the sputum, suggesting intestinal colonization. No differences were seen in the clinical state of patients with P. aeruginosa-negative stool samples and patients with positive stool samples. Toilets in households of P. aeruginosa-infected CF patients were significantly more often contaminated with P. aeruginosa (42%) than toilets in households of non-infected CF patients (20%; P less than 0.03). The study shows that P. aeruginosa-infected CF patients may harbour the organisms also in the intestinal tract, and may spread the bacteria into toilets. Images Fig. 1 PMID:2514111

  14. Effects of WC size and amount on the thermal residual stress in WC–Ni composites

    SciTech Connect

    Seol, K.; Krawitz, A. D.; Richardson, J. W.; Weisbrook, C. M.

    2005-05-01

    We studied the effects of WC particle size and volume fraction on the magnitude and distribution of thermal residual stresses (TRS) in WC–Ni cemented carbide composites by neutron powder diffraction. Samples of high (0.3) and low (0.1) Ni volume fraction and coarse (1.7 m) and fine (0.5 m) WC particle size were employed. Thermal residual strain and stress values were obtained at temperatures between 100 and 900 K. Moreover, the magnitude of the mean (compressive) WC stress increased as WC fraction decreased, while the mean (tensile) Ni stress did the opposite. For both phases, stresses were highest for fine WC particles, reaching over 3 GPa in Ni. Elastic strain distributions, due to the sharp edges and corners of WC particles, were characterized by analyzing diffraction peak widths. The range of stress increased with the magnitude of the TRS. Even though the mean TRS is compressive in WC, regions of tension exist, and, for Ni, regions of compression are present.

  15. Synthesis and Characteristics of WC-Co Alloy Fabricated by Mechanical Alloying and Pressure Sintering

    NASA Astrophysics Data System (ADS)

    Isonishi, Kazuo

    In this paper, the synthesis of WC-Co alloy was investigated. Especially the formation of WC phase during the solid-phase sintering was discussed. The chemical composition of WC-Co was chosen to be WC-20vol%Co. The powder mixture of stoichiometric quantities of elemental powders was mechanical alloyed by using low-energy ball mill under an Ar atmosphere. After 1800ks milling, the X-ray diffraction profile showed only elemental W phase. At DTA runs, W2C and Co6W6C phase formed about 1140K and then transformed to WC and W3Co3C with increasing temperature. Therefore, it is considered that the WC phase synthesized at the sintering process, not milling stage like other investigations. 1800ks milled powder was consolidated by using pulse current sintering method at the temperature of 1373K. The compact consisted mainly of WC with Co and W3Co3C phases. The hardness of the compact was 1648HV and 91.8HRA. The 3-point bending strength was about 2GPa.

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

    NASA Astrophysics Data System (ADS)

    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.

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

    SciTech Connect

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

    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.

  18. Thermal wave imaging of indented diamond coated WC

    SciTech Connect

    Feldman, A.

    1997-07-01

    Photothermal radiometry has been used to obtain thermal wave images in the vicinity of indentations in WC{endash}6{percent}Ni coated with chemical vapor deposited (CVD) diamond. Features in the magnitude and phase of the thermal signal profile are consistent with a one dimensional thermal wave theory that assumes (i) an air gap extending well beyond the visibly observable indented region, and (ii) a thermal resistance interface between the diamond film and the substrate over the entire coated surface. The theory allows us to estimate the air gap thickness, which decreases as the distance from the indented region increases. Air gap variations of tens of nanometers appear to be easily detectable. {copyright} {ital 1997 Materials Research Society.}

  19. Effects of Rare Earth Elements on the Microstructure and Mechanical Properties of HVOF-Sprayed WC-Co Coatings

    NASA Astrophysics Data System (ADS)

    Liu, Yan; Gou, Guoqing; Wang, Xiaomin; Jia, Qiang; Chen, Hui; Tu, Mingjing

    2014-10-01

    Rare earth has been widely used in materials manufacturing to improve hardness and toughness. In this paper, conventional, nanostructured, and rare earth CeO2-doped WC-12Co powders were sprayed by using HVOF spraying technology. Microstructure, hardness, elastic modulus, and fracture toughness of the three coatings were investigated. The results showed that nanostructured WC-12Co coatings possessed the densest microstructure and excellent combination of strength and toughness. The WC particles with the size ranging from 50 to 500 nm distributed uniformly in the nanostructured WC-12Co coating. The average free path of Co matrix in rare earth-doped WC-12Co coating was shorter than that of conventional WC-12Co coating. XRD results showed no obvious decarburization in all three coatings. The addition of rare earth could improve the mechanical properties of the coating compared with that without rare earth. The hardness value of nanostructured WC-12Co coating (12.2 GPa) was similar to that of rare earth-doped WC-12Co coating (12.2 GPa), which was 15.1% higher than that of conventional WC-12Co coating. The elastic modulus and fracture toughness of nanostructured WC-12Co coating were the highest, and that of conventional WC-12Co coating was the lowest.

  20. Development and kinetic analysis of cobalt gradient formation in WC-Co composites

    NASA Astrophysics Data System (ADS)

    Guo, Jun

    2011-12-01

    Functionally graded cemented tungsten carbide (FG WC-Co) is one of the main research directions in the field of WC-Co over decades. Although it has long been recognized that FG WC-Co could outperform conventional homogeneous WC-Co owing to its potentially superior combinations of mechanical properties, until recently there has been a lack of effective and economical methods to make such materials. The lack of the technology has prevented the manufacturing and industrial applications of FG WC-Co from becoming a reality. This dissertation is a comprehensive study of an innovative atmosphere heat treatment process for producing FG WC-Co with a surface cobalt compositional gradient. The process exploited a triple phase field in W-C-Co phase diagram among three phases (solid WC, solid Co, and liquid Co) and the dependence of the migration of liquid Co on temperature and carbon content. WC-Co with a graded surface cobalt composition can be achieved by controlling the diffusion of carbon transported from atmosphere during sintering or during postsintering heat treatment. The feasibility of the process was validated by the successful preparations of FG WC-Co via both carburization and decarburization process following conventional liquid phase sintering. A study of the carburization process was undertaken to further understand and quantitatively modeled this process. The effects of key processing parameters (including heat treating temperature, atmosphere, and time) and key materials variables (involving Co content, WC grain size, and addition of grain growth inhibitors) on the formation of Co gradients were examined. Moreover, a carbon-diffusion controlled kinetic model was developed for simulating the formation of the gradient during the process. The parameters involved in this model were determined by thermodynamic calculations and regression-fit of simulation results with experimental data. In summary, this research first demonstrated the principle of the approach

  1. Cavitation and Sand Slurry Erosion Resistances of WC-10Co-4Cr Coatings

    NASA Astrophysics Data System (ADS)

    Wang, Qun; Tang, Zhaoxi; Cha, Limei

    2015-06-01

    Two WC-10Co-4Cr coatings were deposited by high-velocity oxygen fuel (HVOF) and high-velocity air fuel (HVAF) spray processes, respectively, and their basic mechanical properties, cavitation and sand slurry erosion resistances were investigated. The results show that the HVAF-sprayed WC-10Co-4Cr coating exhibited a lower degree of decarburization and better properties in terms of hardness, fracture toughness, porosity, cavitation and sand slurry erosion resistances than those of the HVOF-sprayed WC-10Co-4Cr coatings, respectively. Therefore, HVAF-sprayed WC-10Co-4Cr coatings may be better employed for the protection of hydro-turbine component surfaces against cavitation and sand slurry erosion.

  2. Controlling corrosion of WC-Co by using an amorphous SiC coating

    NASA Astrophysics Data System (ADS)

    Yeo, Sunmog; Park, Jae-Won

    2012-07-01

    A reduction of WC-Co corrosion was investigated using a potentiodynamic electrochemical test. SiC layers with different thicknesses from 1 to 5 µm were coated on WC-Co by using an ionbeam mixing process. I-V characterization measurements were performed on the SiC-coated WCCo at different conditions: NaOH and H2SO4 solutions and room temperature and 70 °C. The I-V measurements demonstrated that the corrosion current density decreased and the corrosion potential increased as the SiC coating layers got thicker. This finding is evidence that SiC coating layers contact well electrically to WC-Co surfaces and enhance the corrosion properties of WC-Co.

  3. A Study on the Abrasive Resistance of Ni Based Laser Coatings with WC Hard Phase

    NASA Astrophysics Data System (ADS)

    Iždinská, Zita; Brusilová, Alena; Iždinský, Karol

    2011-12-01

    Wear properties of composite laser cladding on the basis of Ni with a 50% presence of WC particles on the dependence of laser beam power output and speed of cladding were investigated in this paper. Properties are compared with reference Ni based laser claddings without WC particles. Laser beam power output of 4.3 and 3.7 kW and cladding speed of 3, 5 and 7 mm/s were used for the preparation of test pieces. All types of prepared claddings were compact without visible internal defects. With increased cladding speed, the hardness of Ni matrix decreased. Wear resistance of Ni based laser claddings with WC particles were dependent on the speed of laser cladding. The presence of WC particles increased the wear resistance of Ni based laser claddings 5 fold.

  4. Evaluation of the apoptogenic potential of hard metal dust (WC-Co), tungsten carbide and metallic cobalt.

    PubMed

    Lombaert, Noömi; De Boeck, Marlies; Decordier, Ilse; Cundari, Enrico; Lison, Dominique; Kirsch-Volders, Micheline

    2004-12-01

    The present study aimed at comparing in vitro the apoptogenic properties of metallic cobalt (Co), tungsten carbide (WC) and tungsten carbide-cobalt (WC-Co) in conditions known to cause genotoxicity. Human peripheral blood mononucleated cells were incubated with 2.0-6.0 microg/ml of Co alone or mixed with WC particles and 33.3-100.0 microg/ml WC alone for up to 24 h. Under these culture conditions the majority (60%) of the cobalt metal particles were almost immediately solubilised in the culture medium, while WC remained under the form of particles that were progressively phagocytosed by monocytes. Apoptosis was assessed by Annexin-V staining, flow cytometry and analysis of DNA fragmentation by ELISA. Metallic Co-particles induced apoptosis in vitro. Furthermore, although so far considered as biologically inert, WC particles also induced apoptosis. When compared with its individual components WC-Co displayed an additive apoptotic effect in the DNA fragmentation assay. Apoptosis induced by WC particles was found largely dependent on caspase-9 activation and occurred presumably in monocytes, while that induced by Co involved both caspase-9 and -8 activation. The data suggest that apoptosis induced by the tested WC-Co mixture results from the additive effects of WC apoptosis induced in monocytes and Co-specific apoptosis in both monocytes and lymphocytes. The apoptogenic properties of these metals may be important in the mechanism of lung pathologies induced by the cobalt-containing particles. PMID:15475175

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

    NASA Astrophysics Data System (ADS)

    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.

  6. Characterizations of WC-10Co nanocomposite powders and subsequently sinterhip sintered cemented carbide

    SciTech Connect

    Shi, X.L. . E-mail: sxl071932@126.com; Shao, G.Q.; Duan, X.L.; Xiong, Z.; Yang, H.

    2006-12-15

    Ultrafine WC-Co cemented carbides, combining high hardness and high toughness, are expected to find broad applications. In this study, WC-10Co-0.4VC-0.4Cr{sub 3}C{sub 2} (wt.%) nanocomposite powders, whose average grain size was about 30 nm, were fabricated by spray pyrolysis-continuous reduction and carbonization technology. The as-prepared nanocomposite powders were characterized and analyzed by chemical methods, scanning electron microscopy (SEM), transmission electron microscopy (TEM), BET analysis and atomic force microscopy (AFM). Furthermore, 'sinterhip' was used in the sintering process, by which ultrafine WC-10Co cemented carbides with an average grain size of 240 nm were prepared. The material exhibited high Rockwell A hardness of HRA 92.8, Vickers hardness HV{sub 1} 1918, and transverse rapture strength (TRS) of 3780 MPa. The homogeneously dispersed grain growth inhibitors such as VC, Cr{sub 3}C{sub 2} in nanocomposite powder and the special nonmetal-metal nanocomposite structure of WC-10Co nanocomposite powder played very important roles in obtaining ultrafine WC-10Co cemented carbide with the desired properties and microstructure. There was an abundance of triple junctions in the ultrafine WC-10Co cemented carbide; these triple junctions endowed the sintered specimen with high mechanical properties.

  7. Faint recombination lines in Galactic PNe with a [WC] nucleus

    NASA Astrophysics Data System (ADS)

    García-Rojas, J.; Peña, M.; Peimbert, A.

    2009-03-01

    Aims: We present spatially resolved high-resolution spectrophotometric data for the planetary nebulae PB 8, NGC 2867, and PB 6. We have analyzed two knots in NGC 2867 and PB 6 and one in PB 8. The three nebulae are ionized by [WC] type nuclei: early [WO] for PB 6 and NGC 2867 and [WC 5-6] in the case of PB 8. Our aim is to study the behavior of the abundance discrepancy problem (ADF) in this type of planetary nebula. Methods: We measured a large number of optical recombination (ORL) and collisionally excited lines (CEL), from different ionization stages (many more than in any previous work), thus, we were able to derive physical conditions from many different diagnostic procedures. We determined ionic abundances from the available collisionally excited and recombination lines. Based on both sets of ionic abundances, we derived total chemical abundances in the nebulae using suitable ionization correction factors. Results: From CELs, we have found abundances typical of Galactic disk planetary nebulae. Moderate ADF(O++) were found for PB 8 (2.57) and NGC 2867 (1.63). For NGC 2867, abundances from ORLs are higher but still consistent with Galactic disk planetary nebulae. On the contrary, PB 8 presents a very high O/H ratio from ORLs. A high C/O was obtained from ORLs for NGC 2867; this ratio is similar to C/O obtained from CELs and with the chemical composition of the wind of the central star, indicating that there was no further C-enrichment in the star, relative to O, after the nebular material ejection. On the contrary, we found C/O<1 in PB 8. Interestingly, we obtain (C/O)ORLs/(C/O)CELs < 1 in PB 8 and NGC 2867; this added to the similarity between the heliocentric velocities measured in [O iii] and O ii lines for our three objects argue against the presence of H-deficient metal-rich knots coming from a late thermal pulse event. Based on data obtained at Las Campanas Observatory, Carnegie Institution. Table 3 is only available in electronic form at http://www.aanda.org

  8. Combined seawater toilet flushing and urine separation for economic phosphorus recovery and nitrogen removal: a laboratory-scale trial.

    PubMed

    Mackey, H R; Zheng, Y-S; Tang, W-T; Dai, J; Chen, G-H

    2014-01-01

    Freshwater toilet flushing consumes 20-35% of typical household water demand. Seawater toilet flushing, as practised by Hong Kong since 1958, provides an alternative water source. To maximise the benefits of this unique dual water supply, urine separation could be combined to allow low-cost struvite production and subsequent urine nitrification - in-sewer denitrification. This paper reports on a laboratory-scale study of seawater urine phosphate recovery (SUPR) and seawater-urine nitrification. A laboratory-scale SUPR reactor was run under three phases with hydraulic retention time between 1.5 and 6 h, achieving 91-96% phosphorus recovery. A urine nitrification sequencing batch reactor (UNSBR) was also run for a period of over 650 days, averaging 90% ammonia removal and loading of up to 750 mg-N/L.d. Careful control of the SUPR phosphate removal was found necessary for operation of the downstream UNSBR, and system integration considerations are discussed. PMID:25259496

  9. Microstructure characteristics of Ni/WC composite cladding coatings

    NASA Astrophysics Data System (ADS)

    Yang, Gui-rong; Huang, Chao-peng; Song, Wen-ming; Li, Jian; Lu, Jin-jun; Ma, Ying; Hao, Yuan

    2016-02-01

    A multilayer tungsten carbide particle (WCp)-reinforced Ni-based alloy coating was fabricated on a steel substrate using vacuum cladding technology. The morphology, microstructure, and formation mechanism of the coating were studied and discussed in different zones. The microstructure morphology and phase composition were investigated by scanning electron microscopy, optical microscopy, X-ray diffraction, and energy-dispersive X-ray spectroscopy. In the results, the coating presents a dense and homogeneous microstructure with few pores and is free from cracks. The whole coating shows a multilayer structure, including composite, transition, fusion, and diffusion-affected layers. Metallurgical bonding was achieved between the coating and substrate because of the formation of the fusion and diffusion-affected layers. The Ni-based alloy is mainly composed of γ-Ni solid solution with finely dispersed Cr7C3/Cr23C6, CrB, and Ni+Ni3Si. WC particles in the composite layer distribute evenly in areas among initial Ni-based alloying particles, forming a special three-dimensional reticular microstructure. The macrohardness of the coating is HRC 55, which is remarkably improved compared to that of the substrate. The microhardness increases gradually from the substrate to the composite zone, whereas the microhardness remains almost unchanged in the transition and composite zones.

  10. Modelling the effects of on-site greywater reuse and low flush toilets on municipal sewer systems.

    PubMed

    Penn, R; Schütze, M; Friedler, E

    2013-01-15

    On-site greywater reuse (GWR) and installation of water-efficient toilets (WET) reduce urban freshwater demand. Research on GWR and WET has generally overlooked the effects that GWR may have on municipal sewer systems. This paper discusses and quantifies these effects. The effects of GWR and WET, positive and negative, were studied by modelling a representative urban sewer system. GWR scenarios were modelled and analysed using the SIMBA simulation system. The results show that, as expected, the flow, velocity and proportional depth decrease as GWR increases. Nevertheless, the reduction is not evenly distributed throughout the day but mainly occurs during the morning and evening peaks. Examination of the effects of reduced toilet flush volumes revealed that in some of the GWR scenarios flows, velocities and proportional depths in the sewer were reduced, while in other GWR scenarios discharge volumes, velocities and proportional depths did not change. Further, it is indicated that as a result of GWR and installation of WET, sewer blockage rates are not expected to increase significantly. The results support the option to construct new sewer systems with smaller pipe diameters. The analysis shows that as the penetration of GWR systems increase, and with the installation of WET, concentrations of pollutants also increase. In GWR scenarios (when toilet flush volume is not reduced) the increase in pollutant concentrations is lower than the proportional reduction of sewage flow. Moreover, the results show that the spatial distribution of houses reusing GW does not significantly affect the parameters examined. PMID:23220603

  11. A Comparison of Mechanical and Tribological Behavior of Nanostructured and Conventional WC-12Co Detonation-Sprayed Coatings

    NASA Astrophysics Data System (ADS)

    Pitchuka, Suresh Babu; Basu, Bikramjit; Sundararajan, G.

    2013-04-01

    In the present study, WC-12Co coatings were deposited by detonation-spraying technique using conventional and nanostructured WC-12Co feedstock at four different oxy/fuel ratios (OF ratio). The coatings exhibited the presence of phases like W2C and W due to the decarburization of the WC phase, and the proportions of these phases were higher in the nano WC-12Co coatings compared with conventional WC-12Co coatings. Coating hardness and fracture toughness were measured. The tribological performance of coatings was examined under dry sand rubber wheel abrasion wear, and solid particle erosion wear conditions. The mechanical and wear properties of coatings were influenced by degree of decarburization and more so in the case of nanostructured WC-Co coatings. The results indicate that the extent of decarburization has a substantial influence on the elastic modulus of the coating which in turn is related to the extent of intersplat cracking of the coating.

  12. Monitoring of Bio-signal of People on Flooring, Tatami and in Bathtub, Toilet

    NASA Astrophysics Data System (ADS)

    Kurihara, Yosuke; Kawanishi, Yoshihiro; Watanabe, Kajiro; Kobayashi, Kazuyuki; Tanaka, Hiroshi

    In the graying Japanese society, monitoring health-related human data with sensors embedded in the living environment is quite meaningful in terms of emergency response and of long-term health management. In using the body data monitoring system daily at home, the lack of invasiveness during the monitoring and the maintenance of the system are of great importance. We have proposed the method to surmise the sleep stages of sleeping subjects by measuring the heartbeats and the respirations without invasiveness using the pneumatic method with an air mattress. This method, however, has a problem in the maintenance, since it requires periodic refilling of the air into the mattress. In this paper, another pneumatic method, which applies silicon tubes instead of the air mattress, is proposed. The change of S/N ratio in heartbeat and respiration signals, while having the environmental noises increased, are compared among a room with wooden flooring, another with tatami mats, a bath tub, and a toilet room. The result shows that both the pulse waves and the breaths can be measured with the accuracy of around 30dB, and the identification of each pulse from among the pulse waves is also feasible, under the condition that the environmental noises in the room with wooden flooring, that with tatami mats, the bath tub, and the rest room are 0.01G, 0.09G, 100ml, and 0.01G respectively.

  13. A case of cutaneous larva migrans acquired from soiled toilet floors in urban Kuala Lumpur.

    PubMed

    Robson, N Z; Othman, S

    2008-10-01

    Despite being a common skin dermatosis in the tropics, physicians in the tropics may miss the diagnosis of cutaneous larva migrans for other pruritic skin manifestation. This is especially in those who live in urban housing with no history of travel. Cutaneous larva migrans, an intensely pruritic skin pathology is mainly contracted by people with history of beach holiday or contact with moist soft sand which had been contaminated with dog or cat faeces. This article reports a patient who presented with intensely itchy papular spots over the dorsum of his foot after walking barefooted in an urban toilet soiled with cat faeces. The patient had initially seen an urban general practitioner who diagnosed the papular skin lesion as an allergic reaction, and prescribed antihistamines. The patient subsequently developed creeping skin lesions and was seen by the author who prescribed albendazole 400 mg twice daily for three days. The patient reported reduction in itching after two days of albendazole treatment and a follow up at ten days revealed a healed infection. PMID:19385496

  14. The Waterless Portable Private Toilet: An Innovative Sanitation Solution in Disaster Zones.

    PubMed

    Kim, Yongkyun; Hashemi, Shervin; Han, Mooyoung; Kim, Tschungil; Sohn, Hong-Gyoo

    2016-04-01

    Catastrophes can occur without warning and inevitably cause short-term and long-term problems. In disaster zones, having an action plan to alleviate difficulties can reduce or prevent many long-lasting complications. One of the most critical and urgent issues is sanitation. Water, energy, personnel, transportation, and the allocation of resources in disaster areas tend to become very limited during emergencies. Sanitation systems suffer in the process, potentially leading to crises due to unsafe and unhygienic surroundings. This article explores the problems of current sanitation practices in disaster areas and identifies the essential characteristics of sustainable sanitation systems. This study also presents a plan for an innovative and sustainable sanitation system using a waterless, portable, private toilet, in addition to a procedure for collecting and disposing waste. The system is agronomic, is socially acceptable, prevents contact with human waste, and can be used for individuals or families. Environmental pollution and social problems (such as sexual harassment) can be reduced both during and after restoration. PMID:26781752

  15. Single house on-site grey water treatment using a submerged membrane bioreactor for toilet flushing.

    PubMed

    Fountoulakis, M S; Markakis, N; Petousi, I; Manios, T

    2016-05-01

    Wastewater recycling has been and continues to be practiced all over the world for a variety of reasons including: increasing water availability, combating water shortages and drought, and supporting environmental and public health protection. Nowadays, one of the most interesting issues for wastewater recycling is the on-site treatment and reuse of grey water. During this study the efficiency of a compact Submerged Membrane Bioreactor (SMBR) system to treat real grey water in a single house in Crete, Greece, was examined. In the study, grey water was collected from a bathtub, shower and washing machine containing significant amounts of organic matter and pathogens. Chemical oxygen demand (COD) removal in the system was approximately 87%. Total suspended solids (TSS) were reduced from 95mgL(-1) in the influent to 8mgL(-1) in the effluent. The efficiency of the system to reduce anionic surfactants was about 80%. Fecal and total coliforms decreased significantly using the SMBR system due to rejection, by the membrane, used in the study. Overall, the SMBR treatment produces average effluent values that would satisfy international guidelines for indoor reuse applications such as toilet flushing. PMID:26901745

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

    SciTech Connect

    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. - 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.

  17. WC/a-C nanocomposite thin films: Optical and electrical properties

    SciTech Connect

    Abad, M. D.; Sanchez-Lopez, J. C.; Cusnir, N.; Sanjines, R.

    2009-02-01

    WC/amorphous carbon (a-C) thin films were deposited by dual magnetron sputtering from individual WC and graphite targets. The influence of film composition and microstructure on the optical and electrical properties was investigated. As evidenced by x-ray photoelectron spectroscopy and grazing angle x-ray diffraction measurements, the WC/a-C films are composite materials made of hexagonal W{sub 2}C and/or cubic {beta}-WC{sub 1-X} nanocrystallites embedded in (a-C) matrix. The optical properties were studied by spectroscopic ellipsometry and the electrical resistivity was measured by the van der Pauw method between 20 and 300 K. Both the optical and the electrical properties of the WC/a-C films are correlated with the chemical composition and microstructure evolution caused by a-C addition. The optical properties of W{sub 2}C/a-C and {beta}-WC{sub 1-x}/a-C films with a-C content {<=}10 at. % are explained by modeling their dielectric functions by a set of Drude-Lorentz oscillators. Further increase in a-C content leads only to the formation of {beta}-WC{sub 1-x}/a-C nanocomposite structures and their optical properties progressively evolve to those of a-C single phase. The electrical resistivity as a function of the temperature of all the films exhibits a negative temperature coefficient of resistivity. Theoretical fitting using the grain-boundary scattering model shows that the transport properties are mainly limited by the grain size and electron mean free path parameters.

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

    NASA Astrophysics Data System (ADS)

    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.

  19. Microstructural and Mechanical Properties of In Situ WC-Fe/Fe Composites

    NASA Astrophysics Data System (ADS)

    Zhong, Lisheng; Yan, Yinglin; Ovcharenko, Vladimir E.; Cai, Xiaolong; Zhang, Xi; Xu, Yunhua

    2015-11-01

    In this study, Fe matrix reinforced with column-shaped WC-Fe composite was designed and fabricated by a novel in situ method. The WC-Fe/Fe composite exhibited a similar structure to that of reinforced concrete. The microstructure, microhardness, impact toughness, and wear resistance of the composites were characterized using scanning electron microscopy, and x-ray diffraction, as well as microhardness, impact, and wear tests. Small amounts of graphite (G), α-Fe, and WC were the predominant phases in the reinforcing bar of the composites. WC particulates improved the wear resistance of the composite, and the highest wear resistance was 96 times higher than that of gray cast iron under a load of 20 N with SiC abrasive particles. The wear resistance mechanism involved protection of the matrix behind the WC bundles by hard carbides. The excellent fracture toughness of the composite was mainly attributed to the disappearance of G flakes from the Fe matrix because of the in situ reaction, which reduced the split action to the matrix. The matrix absorbed a large amount of the crack propagation energy.

  20. Quasi-Plastic Deformation of WC-Co Composites Loaded with a Spherical Indenter

    NASA Astrophysics Data System (ADS)

    Zhang, Haibo; Fang, Zhigang Zak; Belnap, J. Daniel

    2007-03-01

    The quasi-plastic deformation behavior of cemented tungsten carbide (WC-Co) materials was studied using Hertzian indentation techniques. The indentation stress-strain curves of three WC-10 wt pct Co alloys with different hardness values demonstrate that WC-Co alloys exhibit “quasi-plasticity” behavior under indentation load and the increase of indentation stress vs indentation strain bears similarity to “strain hardening” in ductile metals. The analysis of the subsurface indentation damage shows that the mechanisms of the quasi-plastic deformation of WC-Co material are the formation of microcracks. Microcracks were found at heavily damaged areas in all three alloys, and the number of microcracks was higher for the sample with the higher apparent quasi-plasticity. The threshold stress values for the onset of quasi-plastic deformation and formation of ring cracks were determined and used to evaluate the brittleness index of these materials. The correlation of the brittleness index with hardness values gives insight with regard to the brittle or quasi-plastic responses of WC-Co materials.

  1. Survey of attitudes and perceptions of urine-diverting toilets and human waste recycling in Hawaii.

    PubMed

    Lamichhane, Krishna M; Babcock, Roger W

    2013-01-15

    Urine constitutes only about 1% of domestic sewage but contains 50% or more of the excreted nutrients and chemicals like hormones and pharmaceutical residues. Urine diverting toilet (UDT) systems can be considered a more sustainable alternative to wastewater management because they allow nutrient recycling, reduce water use, and allow source-separation of hormones and chemicals that can harm the environment. An online survey was conducted to determine whether UDTs are acceptable to the general public in Hawaii and if attitudes and perceptions towards it and human waste (HW) recycling vary with age, sex, level of education, religious affiliation, ethnicity, and employment status. The survey was also intended to detect possible drivers and barriers for the UDTs. Variations on variables were tested at 5% significance (p=0.05) level (Chi-squared test or ANOVA) and considered significantly different if the p-value was less than 0.05. The results were encouraging as more than 60% are willing to pay extra for the UDT, while only 22% knew that such systems existed. No statistically significant difference was found between males and females on all survey questions at the 5% level. However, females had higher willingness to pay (WTP) than males and WTP increased with age and income. The WTP of Caucasians was higher than Asians and differed significantly. Some respondents expressed concern about the legal provisions for recycling of HW. The survey results indicate that with a public education program, it is possible that most people would be willing to adopt UDTs and HW recycling with incurred societal benefits of reduced water and fertilizer use, reduced greenhouse gas emissions, and collection of micropollutants at the source to prevent their entry into waterways. Because of the small sample size (N=132, 13% response rate) the survey is not representative but may be indicative of the general attitude of Hawaiian people. PMID:23228720

  2. Orientation relationship in WC-Co composite nanoparticles synthesized by in situ reactions

    NASA Astrophysics Data System (ADS)

    Wang, Xilong; Song, Xiaoyan; Liu, Xuemei; Liu, Xingwei; Wang, Haibin; Zhou, Cheng

    2015-04-01

    Using the nanoscale violet tungsten oxide as the tungsten source, the WC-Co composite powder was synthesized by the in situ reactions. The particle size of the WC-Co composite powder has a narrow distribution with the mean particle size below 100 nm, and the single composite particle has a nanocrystalline structure with a mean grain size smaller than 10 nm. The detailed characterizations of the nanoparticle microstructure reveal that the orientation relationship and coherence at the interfaces can form during the in situ reactions and further inherit in the consolidated cemented carbide bulk material. The favorable crystallographic characteristics of the WC-Co composite nanoparticles play a significant role in the enhancement of the mechanical properties of the prepared cemented carbide bulk material.

  3. Physical vapor deposition synthesis of tungsten monocarbide (WC) thin films on different carbon substrates

    SciTech Connect

    Weigert, E. C.; Humbert, M. P.; Mellinger, Z. J.; Ren, Q.; Beebe, T. P. Jr.; Bao, L.; Chen, J. G.

    2008-01-15

    The synthesis of tungsten monocarbide (WC) thin films has been performed by physical vapor deposition on various substrates including glassy carbon, carbon fiber sheet, carbon foam, and carbon cloth. The WC and W{sub 2}C phase contents of these films have been evaluated with bulk and surface analysis techniques such as x-ray diffraction, x-ray photoelectron spectroscopy, and scanning electron microscopy. These characterization techniques were also used to determine the effects of synthesis by nonreactive and reactive sputtering. The synthesis of WC particles supported on the carbon fiber substrate has also been accomplished using the temperature programmed reaction method. Overall, the results demonstrate that the phase purity of tungsten carbides can be controlled by the deposition environment and annealing temperatures.

  4. Erosion-Corrosion Property of CeO2-Modified HVOF WC-Co Coating

    NASA Astrophysics Data System (ADS)

    Liu, Yan; Hang, Zongqiu; Chen, Hui; Ceng, Shengbo; Gou, Guoqing; Wang, Xiaomin; Tu, Mingjing; Wu, Xiangyang

    2016-04-01

    Rare-earth elements have been widely used in materials manufacturing to improve hardness and toughness. In this work, conventional, nanostructured, and CeO2-modified WC-12Co powders were sprayed using high-velocity oxygen flame spraying. The erosion-corrosion behavior and interaction of erosion and corrosion of the coatings in 3.5 wt.% NaCl solution were investigated. In situ observation was employed to analyze the failure mechanism. The results showed that the CeO2-modified WC-12Co coating possessed the best erosion-corrosion resistance, while the lowest corrosion resistance was exhibited by the conventional WC-12Co coating. The results also suggested that the erosion-corrosion mechanism in the three coatings was dominated by corrosion-accelerated erosion. However, the extent of acceleration of erosion by corrosion differed.

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

    NASA Astrophysics Data System (ADS)

    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.

  6. Development of WC-Co Coatings Deposited by Warm Spray Process

    NASA Astrophysics Data System (ADS)

    Chivavibul, Pornthep; Watanabe, Makoto; Kuroda, Seiji; Kawakita, Jin; Komatsu, Masayuki; Sato, Kazuto; Kitamura, Junya

    2008-12-01

    The high-velocity oxy-fuel (HVOF) process is commonly used to deposit WC-Co coatings. There are some problems with this process; especially the decomposition and decarburization of WC during spraying make a coating brittle. To suppress such degradation, the warm spray (WS) process was applied to deposit WC-Co coatings, which is capable of controlling the flame temperature in the range of 500-2000 °C. The microstructure and phases of the deposited coatings were characterized by using SEM and XRD, and the mechanical properties such as hardness, fracture toughness, and wear properties were also investigated. WS process successfully suppressed the formation of the detrimental phases such as W2C and W, which are usually observed in HVOF coatings. The WS coatings showed the similar trend of the hardness variation for Co content with a sintered bulk material. Improvement of toughness and wear behavior was also observed in WS coatings.

  7. Orientation relationship in WC-Co composite nanoparticles synthesized by in situ reactions.

    PubMed

    Wang, Xilong; Song, Xiaoyan; Liu, Xuemei; Liu, Xingwei; Wang, Haibin; Zhou, Cheng

    2015-04-10

    Using the nanoscale violet tungsten oxide as the tungsten source, the WC-Co composite powder was synthesized by the in situ reactions. The particle size of the WC-Co composite powder has a narrow distribution with the mean particle size below 100 nm, and the single composite particle has a nanocrystalline structure with a mean grain size smaller than 10 nm. The detailed characterizations of the nanoparticle microstructure reveal that the orientation relationship and coherence at the interfaces can form during the in situ reactions and further inherit in the consolidated cemented carbide bulk material. The favorable crystallographic characteristics of the WC-Co composite nanoparticles play a significant role in the enhancement of the mechanical properties of the prepared cemented carbide bulk material. PMID:25785577

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

    NASA Astrophysics Data System (ADS)

    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.

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

    PubMed Central

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

    2014-01-01

    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 suggests that therapeutic treatments inhibiting particle internalization may serve as prophylactic approaches for those at risk of WC-Co particle exposure. PMID:24746988

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

    PubMed

    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. PMID:24746988

  11. Spectral analyses of late-type [WC] central stars of planetary nebulae: more empirical constraints for their evolutionary status

    NASA Astrophysics Data System (ADS)

    Leuenhagen, U.; Hamann, W.-R.

    1998-02-01

    The optical spectra of the five recently observed late-type Wolf-Rayet central stars He2-459 ([WC8]), M2-43 ([WC8]), SwSt1 ([WC9]), PM1-188 and IRAS21282+5050 (both [WC11]) are analyzed by means of spherically expanding model atmospheres. The stellar parameters T_* (effective temperature), v_infty (final velocity of the wind), R_* (stellar radius) and dot {M} (mass loss rate) are determined by NLTE simulations which account for the elements hydrogen, helium, carbon and oxygen. With two exceptions (SwSt1 and IRAS21282) the results presented here fit into the sample of already examined [WCL]-type objects. Altogether 13 out of 17 known [WCL]-CSPN have been analyzed so far. The presence of hydrogen in the atmospheres of [WC11] and [WC12] stars becomes more and more evident. In five out of seven analyzed objects of these subtypes hydrogen emission features of stellar origin can be identified. The spectra of the latest subtypes ([WC11], [WC12]) show rather narrow lines and thus allow to detect features of nitrogen (N II, N III), neon (Ne I) and silicon (Si III, Si IV). For the first time we present model calculations accounting for these elements and perform abundance estimates for the eight narrow-lined stars (all [WC11] and [WC12] plus SwSt1). The obtained surface compositions are discussed in the light of recent evolutionary calculations which account for diffuse mixing during thermal pulses on the Asymptotic Giant Branch. Partly based on observations obtained at the German-Spanish Astronomical Center, Calar Alto, Spain

  12. In vitro expression of hard metal dust (WC-Co)--responsive genes in human peripheral blood mononucleated cells.

    PubMed

    Lombaert, Noömi; Lison, Dominique; Van Hummelen, Paul; Kirsch-Volders, Micheline

    2008-03-01

    Hard metals consist of tungsten carbide (WC) and metallic cobalt (Co) particles and are important industrial materials produced for their extreme hardness and high wear resistance properties. While occupational exposure to metallic Co alone is apparently not associated with an increased risk of cancer, the WC-Co particle mixture was shown to be carcinogenic in exposed workers. The in vitro mutagenic/apoptogenic potential of WC-Co in human peripheral blood mononucleated cells was previously demonstrated by us. This study aimed at obtaining a broader view of the pathways responsible for WC-Co induced carcinogenicity, and in particular genotoxicity and apoptosis. We analyzed the profile of gene expression induced in vitro by WC-Co versus control (24 h treatment) in human PBMC and monocytes using microarrays. The most significantly up-regulated pathways for WC-Co treated PBMC were apoptosis and stress/defense response; the most down-regulated was immune response. For WC-Co treated monocytes the most significantly up- and down-regulated pathways were nucleosome/chromatin assembly and immune response respectively. Quantitative RT-PCR data for a selection of the most strongly modulated genes (HMOX1, HSPA1A, HSPA1L, BNIP3, BNIP3L, ADORA2B, MT3, PLA2G7, TNFAIP6), and some additionally chosen apoptosis related genes (BCL2, BAX, FAS, FASL, TNFalpha), confirmed the microarray data after WC-Co exposure and demonstrated limited differences between the Co-containing compounds. Overall, this study provides the first analysis of gene expression induced by the WC-Co mixture showing a large profile of gene modulation and giving a preliminary indication for a hypoxia mimicking environment induced by WC-Co exposure. PMID:18078969

  13. In vitro expression of hard metal dust (WC-Co) - responsive genes in human peripheral blood mononucleated cells

    SciTech Connect

    Lombaert, Nooemi Lison, Dominique; Van Hummelen, Paul; Kirsch-Volders, Micheline

    2008-03-01

    Hard metals consist of tungsten carbide (WC) and metallic cobalt (Co) particles and are important industrial materials produced for their extreme hardness and high wear resistance properties. While occupational exposure to metallic Co alone is apparently not associated with an increased risk of cancer, the WC-Co particle mixture was shown to be carcinogenic in exposed workers. The in vitro mutagenic/apoptogenic potential of WC-Co in human peripheral blood mononucleated cells was previously demonstrated by us. This study aimed at obtaining a broader view of the pathways responsible for WC-Co induced carcinogenicity, and in particular genotoxicity and apoptosis. We analyzed the profile of gene expression induced in vitro by WC-Co versus control (24 h treatment) in human PBMC and monocytes using microarrays. The most significantly up-regulated pathways for WC-Co treated PBMC were apoptosis and stress/defense response; the most down-regulated was immune response. For WC-Co treated monocytes the most significantly up- and down-regulated pathways were nucleosome/chromatin assembly and immune response respectively. Quantitative RT-PCR data for a selection of the most strongly modulated genes (HMOX1, HSPA1A, HSPA1L, BNIP3, BNIP3L, ADORA2B, MT3, PLA2G7, TNFAIP6), and some additionally chosen apoptosis related genes (BCL2, BAX, FAS, FASL, TNF{alpha}), confirmed the microarray data after WC-Co exposure and demonstrated limited differences between the Co-containing compounds. Overall, this study provides the first analysis of gene expression induced by the WC-Co mixture showing a large profile of gene modulation and giving a preliminary indication for a hypoxia mimicking environment induced by WC-Co exposure.

  14. UV-visible marker confirms that environmental persistence of Clostridium difficile spores in toilets of patients with C. difficile-associated diarrhea is associated with lack of compliance with cleaning protocol.e

    PubMed Central

    Alfa, Michelle J; Dueck, Christine; Olson, Nancy; DeGagne, Pat; Papetti, Selena; Wald, Alana; Lo, Evelyn; Harding, Godfrey

    2008-01-01

    Background An ultraviolet visible marker (UVM) was used to assess the cleaning compliance of housekeeping staff for toilets in a tertiary healthcare setting. Methods The UVM was applied to the toilets of patients who were on isolation precautions due to Clostridium difficile-associated diarrhea (CDAD) as well as for patients who were not on isolation precautions. Cleaning was visually scored using a numeric system where 0, 1, 2, and 3 represented; no, light, moderate or heavy residual UVM. Rodac plates containing CDMN selective agar were used to test for the presence of C. difficile on the surfaces of patient's toilets. Results Despite twice daily cleaning for the toilets of patients who were on CDAD isolation precautions, the average cleaning score was 1.23 whereas the average cleaning score for toilets of patients not on isolation precautions was 0.9. Even with optimal cleaning (UVM score of 0) C. difficile was detected from 33% of the samples taken from toilets of patients with CDAD (4% detection in toilet samples from patients who had diarrhea not due to CDAD). Conclusion Our data demonstrated the value of UVM for monitoring the compliance of housekeeping staff with the facility's toilet cleaning protocol. In addition to providing good physical cleaning action, agents with some sporicidal activity against C. difficile may be needed to effectively reduce the environmental reservoir. PMID:18474086

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

    ERIC Educational Resources Information Center

    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…

  16. Tensile and creep rupture behavior of P/M processed Nb-base alloy, WC-3009

    NASA Technical Reports Server (NTRS)

    Hebsur, Mohan G.; Titran, Robert H.

    1988-01-01

    Due to its high strength at temperatures up to 1600 K, fabrication of niobium base alloy WC-3009 (Nb30Hf9W) by traditional methods is difficult. Powder metallurgy (P/M) processing offers an attractive fabrication alternative for this high strength alloy. Spherical powders of WC-3009 produced by electron beam atomizing (EBA) process were successfully consolidated into a one inch diameter rod by vacuum hot pressing and swaging techniques. Tensile strength of the fully dense P/M material at 300-1590 K were similar to the arc-melted material. Creep rupture tests in vacuum indicated that WC-3009 exhibits a class 1 solid solution (glide controlled) creep behavior in the 1480 to 1590 K temperature range and stress range of 14 to 70 MPa. The creep behavior was correlated with temperature and stress using a power law relationship. The calculated stress exponent n, was about 3.2 and the apparent activation energy, Q, was about 270 kJ/mol. The large creep ductility exhibited by WC-3009 was attributed to its high strain rate sensitivity.

  17. Development and investigation of WC-C fixed-point cells

    NASA Astrophysics Data System (ADS)

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

    2012-04-01

    Three cells of the WC-C peritectic fixed point with a temperature of about 3021 K were built and investigated. Two different sources of tungsten with nominal purities of 5N and 3N were used, and two different filling techniques were applied. There was no difference in plateau shapes between the cells. The 3N purity cell showed a small difference (0.22 K) in the melting temperature from the 5N cell, which indicates significant purification of initially contaminated tungsten. The typical melting range and repeatability of the observed peritectic melting plateaux were 100 mK and 15 mK, respectively. The melting point was stable and reproducible within 25 mK per two weeks. T90 temperature of the WC-C melting point was found to be (2747.6 ± 1.1) °C (k = 2). The observed freezing plateaux were flat and repeatable within 50 mK and 15 mK, respectively. The WC1-x-WC eutectic transition showed a melting temperature about 29 K lower than the peritectic one with a repeatability of about 0.2 K. The problem of deep supercooling is discussed and a method for its solution is shown and tested.

  18. Effect of W and WC on the oxidation resistance of yttria-doped silicon nitride

    NASA Technical Reports Server (NTRS)

    Schuon, S.

    1980-01-01

    The effect of W and WC contamination on the oxidation and cracking in air of sintered Si3N4 - 8 w/o Y2O3 ceramics at 500, 750, and 1350 C is examined. A mixture of Si3N4 - 8Y2O3, milled with alumina balls, was divided into four portions. Three portions were doped with 2 w/o WC W, and 4 w/o W respectively, in order to simulate contamination during milling. The fourth portion was undoped and used on a control. The addition of W or WC did not affect the phase relationships in the system, as all bars with or without additions contained melilite as the major Si-Y-O-N phase after sintering. At 750 C, instability (rapid oxidation and cracking) of W-doped bars appears to have occurred as a result of oxidation of the tungsten containing melilite phase. No intermediate temperature instability was observed in bars containing 2 w/o WC or in bars with no additive. Specimens exposed at 1350 C had good oxidation resistance due to the formation of a protective siliceous oxide layer. A specimen containing 4 w/o W which was preoxidized at 1350 C had improved oxidation resistance at 750 C. The tendency towards oxidation and cracking of Si3N4 - 8 Y2O3 at 750 C is concluded to be related to tungsten content of the sintered bars.

  19. Microstructure and Wear Behavior of Conventional and Nanostructured Plasma-Sprayed WC-Co Coatings

    NASA Astrophysics Data System (ADS)

    Sánchez, E.; Bannier, E.; Salvador, M. D.; Bonache, V.; García, J. C.; Morgiel, J.; Grzonka, J.

    2010-09-01

    WC-12%Co coatings were deposited by atmospheric plasma spraying using conventional and nanostructured powders and two secondary plasmogenous gases (He and H2). Coating microstructure and phase composition were characterized using scanning electron microscopy (SEM), transmission electron microscopy (TEM), and x-ray diffraction techniques (XRD) techniques. This study examined wear and friction properties of the coatings under dry friction conditions. SEM was used to analyze abraded surface microstructure. Coating microhardness and fracture toughness were also determined. All coatings displayed strong decarburization as a result of WC decomposition, which gave rise to the formation of secondary phases (W2C and W). A very fine undissolved WC crystalline dispersion coexisted with these new phases. TEM observation confirmed that the matrix was predominantly amorphous and filled with block-type, frequently dislocated crystallites. Wear was observed to follow a three-body abrasive mechanism, since debris between the ball and the coating surface was detected. The main wear mechanism was based on subsurface cracking, owing to the arising debris. WC grain decomposition and dissolution were concluded to be critical factors in wear resistance. The level of decomposition and dissolution could be modified by changing the plasmogenous gas or feed powder grain size. The influence of the plasmogenous gas on wear resistance was greater than the influence of feedstock particle size.

  20. Structure-property correlations in nanostructured WC-12Co microwave clad

    NASA Astrophysics Data System (ADS)

    Zafar, Sunny; Sharma, Apurbba Kumar

    2016-05-01

    Nanostructured materials are known for enhanced properties as compared to their conventional counterparts. In the present work, microwave cladding technique was explored for depositing nanostructured WC-12Co clads on stainless steel substrates. Phase analysis of the WC-12Co microwave clads revealed the presence of Co6W6C, Co7W6, Co3W9C4, W2C and WC phases. The microstructure of the WC-12Co clads confirmed uniform distribution of nano-carbides in the form of clusters enclosed in the carbide network. Mechanical characterisation of the nanostructured clads was carried in terms of microhardness assessment and flexural strength measurement. The microwave induced clads exhibited excellent metallurgical bonding with the substrate and were free from interfacial cracks. The average microhardness of the developed clads was found in the order of 1760 ± 128HV. The flexural strength of the developed clads was observed to be 671 ± 28 MPa. The nanostructured clads exhibited good adhesion with the substrate without getting peeled-off under a load of 3.75 kN and a displacement of 3.72 mm.

  1. Study of W/WC films produced by plasma assisted vacuum arc discharge

    NASA Astrophysics Data System (ADS)

    Ospina, R.; Arango, P.; Arango, Y. C.; Restrepo, E.; Devia, A.

    2005-08-01

    W/WC films were grown by the PAPVD repetitive pulsed vacuum arc technique on 304 stainless steel substrates. To produce the coatings, a target of W with purity of 99.9999% was used. The system is composed by a reaction chamber with two opposite electrodes placed inside it. The target is located on the cathode and the samples on the anode. A pulsed power supply is used to generate the discharge. For the production of the W layer, the chamber was filled with Ar gas at a pressure of 3 mbar, and the voltage of the discharge was 270 V with 3 pulses. WC films were grown in an atmosphere of methane at 3 mbar and a voltage discharge of 275 V with 4 pulses. The active and passive times of the discharge were 1 s and 0.5 s, respectively.XRD technique was employed to study the coatings, to study the present phases and the crystallographic orientation of the films, the XRD analyses were carried out varying the temperature of the system-coating-substrate between room temperature and 600 °C, when the WC coatings are degradated, leaving just the tugsten. XPS analyses present the apparition of WC, WO and WO2 compounds. AFM analyses allowed to measure the morphological properties and the thickness around 3 μm.

  2. Analysis of WC/Ni-Based Coatings Deposited by Controlled Short-Circuit MIG Welding

    NASA Astrophysics Data System (ADS)

    Vespa, P.; Pinard, P. T.; Gauvin, R.; Brochu, M.

    2012-06-01

    This study investigates the recently developed controlled short-circuit metal inert gas (CSC-MIG) welding system for depositing WC/Ni-based claddings on carbon steel substrates. WC/Ni-based coatings deposited by CSC-MIG were analyzed by optical light microscopy and scanning electron microscopy (SEM) equipped with energy dispersive spectroscopy (EDS) and electron backscatter diffraction (EBSD) capabilities. X-ray diffraction (XRD) and hardness measurements of depositions are also reported. The CSC-MIG welding system provides a significant amount of user control over the current waveform during welding and has lower heat input when compared with traditional MIG welding. Heat input for the analyzed coatings ranged from 10.1 to 108.7 J/mm. Metallurgically bonded coatings free from spatter and with 0.75% average porosity were produced. It was found that the detrimental decarburization of the WC particles seen in thermal spray systems does not occur when welding with the CSC-MIG. Precipitation of a reaction layer around the reinforcing phase was identified as WC; the average thickness of which increases from 3.8 to 7.2 μm for the low and high heat input condition, respectively. Precipitation of newly formed WC particles was observed; their size distribution increased from D 50 of 2.4 μm in the low heat input weldment to 6.75 μm in the high heat input weldment. The level of dilution of the reinforcing phase increases significantly with heat input. The hardness of the deposited coatings decreases from 587 HV10 to 410 HV10 when the energy input was increased from 10.1 to 108.7 J/mm.

  3. Influence of substrate hardness transition on built-up of nanostructured WC-12Co by cold spraying

    NASA Astrophysics Data System (ADS)

    Gao, Pei-Hu; Li, Chang-Jiu; Yang, Guan-Jun; Li, Yi-Gong; Li, Cheng-Xin

    2010-01-01

    The ability of cold spray process to retain the feedstock microstructure into coating makes it possible to deposit nanostructured WC-Co coatings. In the present study, the deposition behavior of nanostructured WC-12Co coating was examined through the surface morphology and cross-sectional structure of the deposited single WC-12Co particle impacting on the substrates with different hardness using a nanostructured WC-12Co powder. Substrates included stainless steel, nickel-based self-fluxing alloy coatings with different hardness. It was observed from the top surface and cross-section of individual WC-12Co particles that the penetration leading to particle deposition depends on substrate hardness. When the substrate surface is covered by WC-12Co particles, the hardness of the newly formed substrate, i.e. the coating, increases greatly. The significant increase of the surface hardness leads to the rebounding off of impacting particles and erosion of the deposited particles, which prohibits effective built-up of coating. However, it was found that with spray jet fixed, a deposit with a thickness up to over 700 μm can be built-up. A model involving in substrate hardness transition during deposition is proposed to explain such phenomenon, which can be employed to optimize the conditions to build up a uniform nanostructured WC-12Co coating.

  4. Improvement in tribological properties of atmospheric plasma-sprayed WC-Co coating followed by Cu electrochemical impregnation

    NASA Astrophysics Data System (ADS)

    Yuan, Jianhui; Zhu, Yingchun; Zheng, Xuebing; Ruan, Qichao; Ji, Heng

    2009-06-01

    The WC-Co coating obtained by atmospheric plasma spraying (APS) was modified by Cu electrochemical impregnation. The copper has infiltrated into and filled up the pores in WC-Co coating. The tribological properties of the coating against the stainless steel ball as sliding pairs were investigated with a ball-on-disc (BOD) configuration in air at room temperature. The as-prepared samples were characterized by means of optical microscope, scanning electron microscope and X-ray diffraction. It was found that the frictional behavior of the WC-Co coating followed by Cu electrochemical impregnation was superior to that of WC-Co coating. The wear mechanism of the WC-Co coating followed by Cu electrochemical impregnation was microcutting, whilst that of a WC-Co coating was the fatigue wear. The improvement in tribological properties of the WC-Co coating followed by Cu electrochemical impregnation was attributed to the formation of self-lubricating Cu film on the wear surface which induces the transformation of wear mechanism.

  5. Influence of HVOF sprayed WC/Co coatings on the high-cycle fatigue strength of mild steel

    SciTech Connect

    Steffens, H.D.; Wilden, J.; Nassenstein, K.; Moebus, S.

    1995-12-31

    HVOF thermally sprayed WC/Co coatings are applied onto components which are exposed to wear caused by abrasion, erosion, fretting and sliding. Beside wear attacks and static stresses in lots of cases alternating mechanical stresses caused by dynamic loads occur additionally. Therefore, the fatigue resistance of WC/Co 88/12 and WC/Co 83/17 coated specimens was investigated by high-cycle fatigue tests (HCF). The results of the fatigue tests were documented in statistically ascertained Woehler-diagrams (S-N-curves). Furthermore, the mechanisms of failure are discussed.

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

    NASA Astrophysics Data System (ADS)

    Kadam, Nikhil Rajendra; Karthikeyan, Ganesarethinam

    2016-06-01

    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.

  7. Corrosion, erosion-corrosion and wear resistance of HVOF sprayed WC type coatings with a corrosion resistant binder

    SciTech Connect

    Rogne, T.; Berget, J.; Solem, T.

    1999-07-01

    WC based coatings with high alloy binders were investigated with respect to structure, corrosion and wear. The coatings were made by HVOF spraying of different powders. All powders studied were made by agglomeration/sintering, i.e. agglomeration of metal particles with WC particles with subsequent sintering. Some powders were made using pre-alloyed metal particles. A blend of ceramic-metallic powder and pure metallic powder was also studied. Different methods were used for characterization of the powders and coatings.

  8. ENHANCING PERFORMANCE AND SOCIAL ACCEPTABILITY OF THE VENTILATED IMPROVED PIT TOILET

    EPA Science Inventory

    More than 2.5 billion people worldwide lack access to sanitation facilities, and many regions are behind pace to meet the United Nations Millennium Development Goals’ target of reducing by half the proportion of the population in this predicament by the year 2015. Furthermore...

  9. Electric Contact Strengthening to Improve the Bonding Between WC-Co Coating and 45# Steel Substrate

    NASA Astrophysics Data System (ADS)

    Wang, Yalin; Zhu, Shigen; Gu, Weisheng; Qi, Xiaoben

    2010-09-01

    Adhesion between thermally sprayed coating and the substrate is a type of mechanical bonding. In many cases, the adhesion strength is relatively low. In this study, an electric contact surface strengthening method was used to improve the bonding between thermally sprayed WC/Co coating and 45# steel substrate. Electric contact strengthening equipment was made for this research. Localization of resistive heating was obtained by passing 12-18 kA current through the contact between the electrode and the workpiece, the small size of the contact imposed a severe constriction on the current causing intense resistive heating the contact. In this way, the bonding way between the WC/Co coating and the 45# steel substrate would be changed from mechanical bonding to metallurgical bonding. Orthogonal array design was applied to select the optimum conditions. The effects of different factors and levels have been studied using a statistic method.

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

    PubMed

    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. PMID:8490235

  11. Interfacial reaction in cast WC particulate reinforced titanium metal matrix composites coating produced by laser processing

    NASA Astrophysics Data System (ADS)

    Liu, Dejian; Hu, Peipei; Min, Guoqing

    2015-06-01

    Laser injection of ceramic particle was conducted to produce particulate reinforced metal matrix composites (MMCs) coating on Ti-6Al-4V alloy. Cast WC particle (WCp) was used as injection reinforcement to avoid excessive release of carbon atoms into the melt pool. The interfaces and boundaries between WC and Ti matrix were investigated by electron microscopy study. Compared with single crystal WCp, cast WCp was an appropriate solution to control the reaction products (TiC) in the matrix and the total amount of reaction products was significantly reduced. Irregular-shape reaction layers were formed around cast WCp. The reaction layers consist of a W2C layer and a mixed layer of W and TiC. Such reaction layers are effective in load transfer under an external load.

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

    NASA Astrophysics Data System (ADS)

    Budi, Esmar; Razali, M. Mohd.; Nizam, A. R. Md.

    2013-09-01

    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.

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

    SciTech Connect

    Budi, Esmar; Razali, M. Mohd.; Nizam, A. R. Md.

    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.

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

    NASA Astrophysics Data System (ADS)

    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.

  15. Effectiveness of the WC/rBS oral cholera vaccine in the prevention of traveler's diarrhea

    PubMed Central

    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

    2013-01-01

    Objective: 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. Methods: 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. Findings: 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). Conclusions: 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. PMID:23324573

  16. Parameter study of HP/HVOF deposited WC-Co coatings

    NASA Astrophysics Data System (ADS)

    de Villiers Lovelock, H. L.; Richter, P. W.; Benson, J. M.; Young, P. M.

    1998-03-01

    The deposition parameters of WC-17% Co coatings produced using the JP-5000 liquid-fuel HP/HVOF system (Eutectic TAFA) were investigated with the initial purpose of parameter improvement and optimization. The coating microstructures, porosities, phase compositions, and abrasion resistance were characterized. Preliminary work using the Taguchi statistical experimental design method aimed at optimizing the spray parameters in terms of the microstructure and phase composition was unsuccessful. The variations in the measured properties were too small to be correlated with the spray parameters. Subsequent experiments showed this was primarily due to the fact that the properties, particularly the abrasion resistance, of the WC-Co coatings were not primarily influenced by variations in the spray parameters, but were more dependent on the powder composition, particle size range, and manufacturing route. Hence, the application of Taguchi techniques would have been more effective over a much wider parameter space than was originally used. This result is valuable because it suggests that this process is robust and can be used for WC-Co coatings without large investments in spray parameter optimization and control once the coating and powder type have been fixed.

  17. Effect of W and WC on the oxidation resistance of yttria-doped silicon nitride

    NASA Technical Reports Server (NTRS)

    Schuon, S.

    1980-01-01

    The effect of tungsten and tungsten carbide contamination on the oxidation and cracking in air of yttria-doped silicon nitride ceramics is investigated. Silicon nitride powder containing 8 wt % Y2O3 was doped with 2 wt % W, 4 wt % W, 2 wt % WC or left undoped, and sintered in order to simulate contamination during milling, and specimens were exposed in air to 500, 750 and 1350 C for various lengths of time. Scanning electron and optical microscopy and X-ray diffraction of the specimens in the as-sintered state reveals that the addition of W or WC does not affect the phase relationships in the system, composed of alpha and beta Si3N4, melilite and an amorphous phase. Catastrophic oxidation is observed at 750 C in specimens containing 2 and 4 wt % W, accompanied by the disappearance of alpha Si3N4 and melilite from the structure. At 1350 C, the formation of a protective glassy oxide layer was observed on all specimens without catastrophic oxidation, and it is found that pre-oxidation at 1350 C also improved the oxidation resistance at 750 C of bars doped with 4 wt % W. It is suggested that tungsten contamination from WC grinding balls may be the major cause of the intermediate-temperature cracking and instability frequently observed in Si3N4-8Y2O3.

  18. Wear properties of compact graphite cast iron with bionic units processed by deep laser cladding WC

    NASA Astrophysics Data System (ADS)

    Zhou, Hong; Zhang, Peng; Sun, Na; Wang, Cheng-tao; Lin, Peng-yu; Ren, Lu-quan

    2010-08-01

    By simulating the cuticles of some soil animals, the wear resistance of compact graphite cast iron (CGI) processed by laser remelting gets a conspicuous improvement. In order to get a further anti-wear enhancement of CGI, a new method of deep laser cladding was used to process bionic units. By preplacing grooves then filling with WC powders and laser cladding, the bionic units had a larger dimension in depth and higher microhardness. Fe powder with different proportions from 30% (wt.) to 60% (wt.) was added into WC before laser processing for a good incorporation with CGI substrate. The improved laser cladding units turned out to induce higher wear resistance in comparison with laser remelting ones. The depth of the layer reached up to 1 mm. The results of dry sliding wear tests indicated that the specimen processed by laser cladding has a remarkable improvement than the ones processed by laser remelting. It should be noted that the wear mass loss was essentially dependent on the increase in WC proportion.

  19. Effect of annealing on microstructure and mechanical properties of laser deposited Co-285+WC coatings

    NASA Astrophysics Data System (ADS)

    Sun, G. F.; Wang, K.; Zhou, R.; Tong, Z. P.; Fang, X. Y.

    2015-03-01

    Laser deposited Co-285+WC coating was heat treated at 500 °C (stress relief annealing) for 60 min and cooled to room temperature in a furnace. Optical, scanning microscopy and X-ray diffractometer were used to investigate the microstructure and phases in the coating. An X-ray stress analyzer was used to study the effect of heat treatment on the residual stress in the coating. A microhardness tester and wear tester were used to test the microhardness distribution and friction and wear behavior. A lot of precipitates formed in the annealed Co-285+WC coating. Residual stress and FWHM (full width at half-maximum) of the coating were decreased by annealing. Residual stress values and microhardness decreased by 22-88% and 39%, respectively. Friction coefficient seldom changed by annealing, but circulation of oxide films was brought forward. Relative wear resistance of the annealed Co-285+WC coating was 6.8 times that of the as-deposited coating. Mechanism of the effect of annealing on microstructure, FWHM, residual stress and wear properties were discussed.

  20. Microstructure evolution of WC/steel composite by laser surface re-melting

    NASA Astrophysics Data System (ADS)

    Xianqing, You; Chengjun, Zhang; Xuefeng, Song; Manping, Huang; Jianguo, Ma

    2007-02-01

    WC/steel composites fabricated by electro-slag melting and casting were re-melted by transverse flow CO 2 laser. Optical microscopy, scanning electron microscopy, energy dispersive spectroscopy, X-ray diffraction and transmission electron microscopy were used to analyze the microstructure evolution in laser melted layer. It was found that the laser-affected zone has three distinguished zones, the melted, transient and heat affected zone. The phases of the melted zone were composed of WC, Fe 3W 3C, (Cr,Fe) 7C 3, martensite and retained austenite. The microstructure evolution in the melted zone was represented by the transformation of three parts including the steel matrix, WC particles cluster and dispersed carbides. A significant reactant was herringbone eutectic carbide of Fe 3W 3C. The effect of laser scanning rate was mainly behaved in affecting the melt depth, microstructure of transient zone and dissolution of medium carbides. In comparison with the substrate, the melted zone has much higher microhardness.

  1. Sliding and Abrasive Wear Behavior of WC-CoCr Coatings with Different Carbide Sizes

    NASA Astrophysics Data System (ADS)

    Thakur, Lalit; Arora, Navneet

    2013-02-01

    This study examines the sliding and abrasive wear behaviors of high-velocity oxy-fuel (HVOF)-sprayed WC-CoCr coatings with different WC grain sizes. The HVOF coating deposition was assisted by in-flight particle temperature and velocity measurement system. The powder feedstocks and their corresponding coatings were characterized by means of XRD and Field Emission Scanning Electron Microscope analysis. Hardness, porosity, and indentation fracture toughness of these coatings were calculated and compared with each other. Sliding wear resistance of these coatings was calculated using pin-on-disk tribometer (ASTM G99-90). The two-body abrasion was quantified by sliding the samples over silicon carbide (SiC) abrasive paper bonded to a rotating flat disk of auto-polisher. The mechanism of materials' removal in both the sliding and abrasive wears was studied and discussed on microstructural investigations. It was observed that fine grain WC-CoCr cermet coating exhibits higher sliding and abrasive wear resistances as compared with conventional cermet coating.

  2. Deposition of WC-Co Coatings by a Novel High Pressure HVOF

    NASA Astrophysics Data System (ADS)

    Sun, Bo; Fukanuma, Hirokata

    2013-03-01

    WC-Co coatings are primarily deposited using the high velocity oxy-fuel (HVOF) spray process. However, the decomposition and decarburization of carbides during spraying affects the wear performance and fracture toughness of the coatings. In this paper, a novel high pressure HVOF was developed to achieve lower particle temperature and higher particle velocity. It enables combustion chamber pressures up to 3.0 MPa. The influence of combustion chamber pressure and oxygen/fuel ratio on WC-Co particle velocity and temperature levels were analyzed by numerical simulation. The experimental results show that the combustion chamber pressure and the oxygen/fuel ratio have a significant influence on particle velocity and melting degree, as well as on the microstructure and microhardness of the coating. High velocity WC-Co particles in different states, i.e., molten, semi-molten, and non-molten can be readily obtained by changing the spraying conditions. A comparison to the conventional JP-5000 was also performed.

  3. Preparation and Characterization of Ir Coating on WC Ceramic by Double Glow Plasma

    NASA Astrophysics Data System (ADS)

    Zhang, Zhongwei; Xu, Zhenghui; Wang, Jinming; Wu, Wangping; Chen, Zhaofeng

    2012-10-01

    Dense and adherent Ir coating was deposited on porous WC ceramic by double glow plasma (DGP). There were two cathodes in the vacuum deposition chamber. The bias voltage of Ir target and WC substrate were -900 and -350 V, respectively. The Ir coating was characterized using scanning electron microscopy, x-ray diffraction, nanoindentation instrument, and scratch tester to examine the microstructure and the mechanical properties. The results indicated that the deposition rate by DGP was up to 5-6 μm/h which was faster than that by metal-organic chemical vapor deposition and magnetron sputtering. The Ir coating had a preferential growth orientation of (220) crystal face. The hardness was 800 HV. The elastic modulus was 644 GPa. The excellent mechanical properties were attributed to the preferential growth, the large compressive stress, and the shrinkage of the lattice parameters. The adhesive force was up to 51 N. The strong adhesion was attributed to the mechanical locking and chemical reaction between the Ir coating and the porous WC substrate.

  4. Effect of Powder Characteristics on Properties of Warm-Sprayed WC-Co Coatings

    NASA Astrophysics Data System (ADS)

    Chivavibul, Pornthep; Watanabe, Makoto; Kuroda, Seiji; Kawakita, Jin; Komatsu, Masayuki; Sato, Kazuto; Kitamura, Junya

    2010-01-01

    In high-velocity oxy-fuel (HVOF) spraying of WC-Co coatings, the decomposition and decarburization of WC during deposition are responsible for their much lower toughness compared with a sintered bulk WC-Co. In a previous study, Warm Spray (WS) process, which is capable to control the flame temperature used to propel powder particles, was successfully applied in an attempt to suppress such detrimental reactions by keeping particles’ temperature lower than their melting point. The coatings deposited by WS process showed no or little formation of W2C and η phases and demonstrated moderately improved fracture properties. However, there is still a gap in fracture toughness between WS coatings and the corresponding sintered bulk. In order to optimize the properties of the WS coatings, the effect of original powder sizes were investigated. Microstructural characterization and phase analysis were carried out on deposited coatings by SEM and XRD. The results show that the feedstock powder size has substantial effects on the properties of the coatings, i.e., the smaller powder showed improved properties.

  5. Microstructure and corrosion properties of thick WC composite coating formed by plasma cladding

    NASA Astrophysics Data System (ADS)

    Guozhi, Xie; Xiaolong, Song; Dongjie, Zhang; Yuping, Wu; Pinghua, Lin

    2010-08-01

    The thick Ni-coated WC coatings, in a matrix of Nickel-based alloys, were prepared on AISI 1045 steel using plasma cladding equipment. A pre-placed layer of uniform mixture, with different weight fractions of Ni-coated WC powder and Nickel-based alloy powder, on the steel substrate was melted at the high temperature of the plasma jet. The coating composition, microstructure and microhardness were analyzed by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive spectrometer (EDS) and microhardness testing. The experimental results show that the metallurgical bond was formed between the coating and substrate. The XRD results show that the coatings contain γ-Ni, carbides (such as M 23C 6 and M 7C 3) and boride (such as Fe 2B, Fe 3B phases). SEM shows that all the coatings are crack-free with lower porosity (<1%). It is found that the microhardness and the electrochemical behavior of the coatings are depended on the content of Ni-coated WC powder. The corrosion mechanism for the coatings may be due to the microgalvance corrosion between the phases in the cladding coatings.

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

    NASA Astrophysics Data System (ADS)

    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.

  7. Evaluation of Solvita compost stability and maturity tests for assessment of quality of end-products from mixed latrine style compost toilets

    SciTech Connect

    Hill, Geoffrey B.; Baldwin, Susan A.; Vinnerås, Bjorn

    2013-07-15

    Highlights: • Solvita® stability and maturity tests used on composting toilet end-product. • Solvita® ammonia better suited in evaluation of feedstock suitability for vermicomposting. • No clear value of Solvita® stability test due to prevalent inhibition of decomposition by ammonia. - Abstract: It is challenging and expensive to monitor and test decentralized composting toilet systems, yet critical to prevent the mismanagement of potentially harmful and pathogenic end-product. Recent studies indicate that mixed latrine composting toilets can be inhibited by high ammonia content, a product of urea hydrolysis. Urine-diverting vermicomposting toilets are better able to accomplish the goals of remote site human waste management by facilitating the consumption of fecal matter by earthworms, which are highly sensitive to ammonia. The reliability of Solvita® compost stability and maturity tests were evaluated as a means of determining feedstock suitability for vermicomposting (ammonia) and end-product stability/completeness (carbon dioxide). A significant linear regression between Solvita® ammonia and free ammonia gas was found. Solvita® ranking of maturity did not correspond to ranking assigned by ammonium:nitrate standards. Solvita® ammonia values 4 and 5 contained ammonia levels below earthworm toxicity limits in 80% and 100% of samples respectively indicative of their use in evaluating feedstock suitability for vermicomposting. Solvita® stability tests did not correlate with carbon dioxide evolution tests nor ranking of stability by the same test, presumably due to in situ inhibition of decomposition and microbial respiration by ammonia which were reported by the Solvita® CO{sub 2} test as having high stability values.

  8. Evaluation of Solvita compost stability and maturity tests for assessment of quality of end-products from mixed latrine style compost toilets.

    PubMed

    Hill, Geoffrey B; Baldwin, Susan A; Vinnerås, Bjorn

    2013-07-01

    It is challenging and expensive to monitor and test decentralized composting toilet systems, yet critical to prevent the mismanagement of potentially harmful and pathogenic end-product. Recent studies indicate that mixed latrine composting toilets can be inhibited by high ammonia content, a product of urea hydrolysis. Urine-diverting vermicomposting toilets are better able to accomplish the goals of remote site human waste management by facilitating the consumption of fecal matter by earthworms, which are highly sensitive to ammonia. The reliability of Solvita compost stability and maturity tests were evaluated as a means of determining feedstock suitability for vermicomposting (ammonia) and end-product stability/completeness (carbon dioxide). A significant linear regression between Solvita ammonia and free ammonia gas was found. Solvita ranking of maturity did not correspond to ranking assigned by ammonium:nitrate standards. Solvita ammonia values 4 and 5 contained ammonia levels below earthworm toxicity limits in 80% and 100% of samples respectively indicative of their use in evaluating feedstock suitability for vermicomposting. Solvita stability tests did not correlate with carbon dioxide evolution tests nor ranking of stability by the same test, presumably due to in situ inhibition of decomposition and microbial respiration by ammonia which were reported by the Solvita CO2 test as having high stability values. PMID:23647950

  9. Genotoxicity of tungsten carbide-cobalt (WC-Co) nanoparticles in vitro: mechanisms-of-action studies.

    PubMed

    Moche, Hélène; Chevalier, Dany; Vezin, Hervé; Claude, Nancy; Lorge, Elisabeth; Nesslany, Fabrice

    2015-02-01

    We showed previously that tungsten carbide-cobalt (WC-Co) nanoparticles (NP) can be used as a nanoparticulate positive control in some in vitro mammalian genotoxicity assays. Here, we investigate the mechanisms of action involved in WC-Co NP genotoxicity in L5178Y mouse lymphoma cells and primary human lymphocytes, in vitro. Data from the micronucleus assay coupled with centromere staining and from the chromosome-aberration assay show the involvement of both clastogenic and aneugenic events. Experiments with the formamidopyrimidine DNA glycosylase (FPG)-modified comet assay showed a slight (non-significant) increase in FPG-sensitive sites in the L5178Y mouse lymphoma cells but not in the human lymphocytes. Electron paramagnetic resonance spin-trapping results showed the presence of hydroxyl radicals (•OH) in WC-Co NP suspensions, with or without cells, but with time-dependent production in the presence of cells. However, a significant difference in •OH production was observed between human lymphocytes from two different donors. Using H2O2, we showed that WC-Co NP can participate in Fenton-like reactions. Thus, •OH might be produced either via intrinsic generation by WC-Co NP or through a Fenton-like reaction in the presence of cells. PMID:25813722

  10. Fe3W3C/WC/graphitic carbon ternary nanojunction hybrids for dye-sensitized solar cells.

    PubMed

    Liao, Yongping; Xie, Ying; Pan, Kai; Wang, Guofeng; Pan, Qingjiang; Zhou, Wei; Wang, Lei; Jiang, Baojiang; Fu, Honggang

    2015-02-01

    Fe3 W3 C/WC/graphitic carbon (GC) ternary nanojunction hybrids are synthesized through a solid-state pyrolysis process for dye-sensitized solar cells (DSSCs). First-principles calculations have been first employed to investigate the adsorption energy between I3 (-) and Fe3 W3 C and WC nanoclusters. Scanning Kelvin probe images indicate that the work function changes greatly due to the formation of ternary nanojunctions, which favor fast photoelectron transfer. A photoelectrical conversion efficiency of 7.1 % is achieved based on Fe3 W3 C/WC/GC hybrid counter electrodes, which is much higher than those of pure GC (5.02 %) and WC/GC hybrids (6.11 %). It has been further revealed that Fe3 W3 C/WC/GC hybrid counter electrodes exhibit the best catalytic performances according to relevant electrochemical measurements, which can be attributed to fast photoelectron transfer due to the ternary junctions and the addition of Fe3 W3 C with more catalytic metallic atoms. PMID:25581098

  11. Structure, optical properties and thermal stability of Al2O3-WC nanocomposite ceramic spectrally selective solar absorbers

    NASA Astrophysics Data System (ADS)

    Gao, Xiang-Hu; Wang, Cheng-Bing; Guo, Zhi-Ming; Geng, Qing-Fen; Theiss, Wolfgang; Liu, Gang

    2016-08-01

    Traditional metal-dielectric composite coating has found important application in spectrally selective solar absorbers. However, fine metal particles can easily diffuse, congregate, or be oxidized at high temperature, which causes deterioration in the optical properties. In this work, we report a new spectrally selective solar absorber coating, composed of low Al2O3 ceramic volume fraction (Al2O3(L)-WC) layer, high Al2O3 ceramic volume fraction (Al2O3(H)-WC layer) and Al2O3 antireflection layer. The features of our work are: 1) compared with the metal-dielectric composites concept, Al2O3-WC nanocomposite ceramic successfully achieves the all-ceramic concept, which exhibits a high solar absorptance of 0.94 and a low thermal emittance of 0.08, 2) Al2O3 and WC act as filler material and host material, respectively, which are different from traditional concept, 3) Al2O3-WC nanocomposite ceramic solar absorber coating exhibits good thermal stability at 600 °C. In addition, the solar absorber coating is successfully modelled by a commercial optical simulation programme, the result of which agrees with the experimental results.

  12. Electrideposition and Wear Behavior of Nano-Structured Cr-WC Composite Coatings from a Trivalent Chromium Bath

    NASA Astrophysics Data System (ADS)

    Amadeh, A.; Nadali, S.; Lari Baghal, S. M.; Moradi, H.

    Electrodeposition of nano-structured Cr-WC had been carried out from a trivalent chromium bath using a square shaped pulse current. The average size of WC particles was 70 nm. The effect of sodium saccharin and sodium dodecyl sulfate (SDS) additives as well as pulse electroplating parameters such as current density, duty cycle and frequency on the amount of incorporated WC particles and morphology of the coatings was investigated. The structure and morphology of the coatings were studied by X-ray diffraction (XRD) and scanning electron microscopy (SEM) techniques. In addition, the hardness and tribological behavior of the coatings were investigated by microhardness and pin on disk methods, respectively. The results showed that although the addition of saccharin and SDS decreased the amount of WC particles in the coating, but reduced the size of WC agglomerates which, in turn, increased the wear resistance of the coatings. Also, the optimum wear resistance was achieved at the current density of 8 A/dm2, duty cycle of 50% and frequency of 10 Hz.

  13. The 6-Aminoquinolone WC5 Inhibits Human Cytomegalovirus Replication at an Early Stage by Interfering with the Transactivating Activity of Viral Immediate-Early 2 Protein ▿ †

    PubMed Central

    Loregian, Arianna; Mercorelli, Beatrice; Muratore, Giulia; Sinigalia, Elisa; Pagni, Silvana; Massari, Serena; Gribaudo, Giorgio; Gatto, Barbara; Palumbo, Manlio; Tabarrini, Oriana; Cecchetti, Violetta; Palù, Giorgio

    2010-01-01

    WC5 is a 6-aminoquinolone that potently inhibits the replication of human cytomegalovirus (HCMV) but has no activity, or significantly less activity, against other herpesviruses. Here we investigated the nature of its specific anti-HCMV activity. Structure-activity relationship studies on a small series of analogues showed that WC5 possesses the most suitable pattern of substitutions around the quinolone scaffold to give potent and selective anti-HCMV activity. Studies performed to identify the possible target of WC5 indicated that it prevents viral DNA synthesis but does not significantly affect DNA polymerase activity. In yield reduction experiments with different multiplicities of infection, the anti-HCMV activity of WC5 appeared to be highly dependent on the viral inoculum, suggesting that WC5 may act at an initial stage of virus replication. Consistently, time-of-addition and time-of-removal studies demonstrated that WC5 affects a phase of the HCMV replicative cycle that precedes viral DNA synthesis. Experiments to monitor the effects of the compound on virus attachment and entry showed that it does not inhibit either process. Evaluation of viral mRNA and protein expression revealed that WC5 targets an event of the HCMV replicative cycle that follows the transcription and translation of immediate-early genes and precedes those of early and late genes. In cell-based assays to test the effects of WC5 on the transactivating activity of the HCMV immediate-early 2 (IE2) protein, WC5 markedly interfered with IE2-mediated transactivation of viral early promoters. Finally, WC5 combined with ganciclovir in checkerboard experiments exhibited highly synergistic activity. These findings suggest that WC5 deserves further investigation as a candidate anti-HCMV drug with a novel mechanism of action. PMID:20194695

  14. Anaerobic digestion of blackwater from vacuum toilets and kitchen refuse in a continuous stirred tank reactor (CSTR).

    PubMed

    Wendland, C; Deegener, S; Behrendt, J; Toshev, P; Otterpohl, R

    2007-01-01

    The objective of this research was mesophilic anaerobic digestion of blackwater from vacuum toilets (BW) and kitchen refuse (KR) in a CSTR within an ecological sanitation system. A detailed investigation of the BW characteristics was carried out. Research on anaerobic digestion was performed with CSTR of 101 volume at HRT of 10, 15 and 20 days. The digestion of BW at 20 days HRT showed stable performance without inhibition effects, in spite of relatively high ammonium concentrations. The removal of total and particulate COD was 61% and 53%, respectively, and the methane yield 10/CH4/cap/day. The addition of kitchen refuse (KR) improved the performance of the CSTR in terms of COD removal efficiency and methane yield. At 20 days HRT the removal of total and particulate COD increased up to 71% and 67%, respectively, and the methane yield to 27/CH4/cap/day. The results at 15 days HRT showed similar performance. At HRT of 10 days, the anaerobic treatment was limited but reached steady state conditions at higher VFA concentrations in the effluent, with a decrease of COD removal of 30 to 33% and of methane yields of 19 to 21%. PMID:17506437

  15. Toilet compost and human urine used in agriculture: fertilizer value assessment and effect on cultivated soil properties.

    PubMed

    Sangare, D; Sou Dakoure, M; Hijikata, N; Lahmar, R; Yacouba, H; Coulibaly, L; Funamizu, N

    2015-01-01

    Toilet compost (TC) and human urine are among natural fertilizers, which raise interest due to their double advantages to combine sanitation and nutrient recovery. However, combination of urine and TC is not so spread probably because the best ratio (urine/TC) is still an issue and urine effect on soil chemical properties remains poorly documented. This study aims to determine the best ratio of urine and TC in okra cultivation, by targeting higher fertilization effect combined with lower impact on soil chemical properties. Based on Nitrogen requirement of okra, seven treatments were compared: (T0) no fertilizer, (T1) chemical fertilizer (NPK: 14-23-14), (T2) 100% urine, (T3) 100% TC, (T4) ratio of 75% urine+25% TC, (T5) 50% urine+50% TC and (T6) 25% urine+75% TC. Results indicated that T4 (75% urine+25% TC) gave the highest plant height and yield. In contrast, T2 (100% urine) gave the lowest results among all treatments, indicating toxicity effects on plant growth and associated final yield. Such toxicity is confirmed by soil chemical properties at T2 with soil acidification and significant increase in soil salinity. In contrast, application of urine together with TC mitigates soil acidification and salinity, highlighting the efficiency of urine and TC combination on soil chemical properties. However, further investigation is necessary to refine better urine/TC ratio for okra production. PMID:25371046

  16. A comparative human health risk assessment of p-dichlorobenzene-based toilet rimblock products versus fragrance/surfactant-based alternatives.

    PubMed

    Aronson, Dallas B; Bosch, Stephen; Gray, D Anthony; Howard, Philip H; Guiney, Patrick D

    2007-10-01

    A comparison of the human health risk to consumers using one of two types of toilet rimblock products, either a p-dichlorobenzene-based rimblock or two newer fragrance/surfactant-based alternatives, was conducted. Rimblock products are designed for global use by consumers worldwide and function by releasing volatile compounds into indoor air with subsequent exposure presumed to be mainly by inhalation of indoor air. Using the THERdbASE exposure model and experimentally determined emission data, indoor air concentrations and daily intake values were determined for both types of rimblock products. Modeled exposure concentrations from a representative p-dichlorobenzene rimblock product are an order of magnitude higher than those from the alternative rimblock products due to its nearly pure composition and high sublimation rate. Lifetime exposure to p-dichlorobenzene or the subset of fragrance components with available RfD values is not expected to lead to non-cancer-based adverse health effects based on the exposure concentrations estimated using the THERdbASE model. A similar comparison of cancer-based effects was not possible as insufficient data were available for the fragrance components. PMID:17934948

  17. Lamellipodia and Membrane Blebs Drive Efficient Electrotactic Migration of Rat Walker Carcinosarcoma Cells WC 256

    PubMed Central

    Sroka, Jolanta; Krecioch, Izabela; Zimolag, Eliza; Lasota, Slawomir; Rak, Monika; Kedracka-Krok, Sylwia; Borowicz, Pawel; Gajek, Marta; Madeja, Zbigniew

    2016-01-01

    The endogenous electric field (EF) may provide an important signal for directional cell migration during wound healing, embryonic development and cancer metastasis but the mechanism of cell electrotaxis is poorly understood. Additionally, there is no research addressing the question on the difference in electrotactic motility of cells representing various strategies of cell movement—specifically blebbing vs. lamellipodial migration. In the current study we constructed a unique experimental model which allowed for the investigation of electrotactic movement of cells of the same origin but representing different modes of cell migration: weakly adherent, spontaneously blebbing (BC) and lamellipodia forming (LC) WC256 cells. We report that both BC and LC sublines show robust cathodal migration in a physiological EF (1–3 V/cm). The directionality of cell movement was completely reversible upon reversing the field polarity. However, the full reversal of cell direction after the change of EF polarity was much faster in the case of BC (10 minutes) than LC cells (30 minutes). We also investigated the distinct requirements for Rac, Cdc42 and Rho pathways and intracellular Ca2+ in electrotaxis of WC256 sublines forming different types of cell protrusions. It was found that Rac1 is required for directional movement of LC to a much greater extent than for BC, but Cdc42 and RhoA are more crucial for BC than for LC cells. The inhibition of ROCK did not affect electrotaxis of LC in contrast to BC cells. The results also showed that intracellular Ca2+ is essential only for the electrotactic reaction of BC cells. Moreover, inhibition of MLCK and myosin II did not affect the electrotaxis of LC in contrast to BC cells. In conclusion, our results revealed that both lamellipodia and membrane blebs can efficiently drive electrotactic migration of WC 256 carcinosarcoma cells, however directional migration is mediated by different signalling pathways. PMID:26863616

  18. Effect of Plasma Nitriding on the Performance of WC-Co Cutting Tools

    NASA Astrophysics Data System (ADS)

    Hamzaoglu, Ebru; Yilmaz, Safak; Gulmez, Turgut

    2011-04-01

    This paper presents the effect of nitriding process parameters on the cutting performance of WC-Co tools. The cutting performance was measured by CNC machining of GG25 cast iron parts. The hardness and phase composition of nitrided layer were determined for different plasma nitriding temperatures and times. The hardness of the nitrided layer increased at all plasma nitrided conditions investigated. However, the machining performance of the cutting inserts varied in the range between a 60% increase and a 40% decrease after plasma nitriding. The maximum number of machined parts was seen when the insert was nitrided at 600 °C-4 h and at 500 °C-4 h.

  19. Safety-analysis report for packaging: the ORNL DOT specification 20WC-5 - special form packaging

    SciTech Connect

    Schaich, R.W.

    1983-03-01

    The ORNL DOT Specification 20WC-5 - Special Form Packaging was fabricated at the Oak Ridge National Laboratory (ORNL) for the transport of large quantities of solid non-fissile radioactive materials in special form. the package was evaluated on the basis of tests performed at Sandia National Laboratories, Albuquerque, New Mexico (formerly Sandia Corporation), on an identical fire and impact shield and special form tests performed on a variety of stainless steel capsules at ORNL by Operations Division personnel. The results of these evaluations demonstrate that the package is in compliance with the applicable regulations for the transport of large quantities of non-fissile radioactive materials in special form. 7 figures.

  20. Web Accessibility and Accessibility Instruction

    ERIC Educational Resources Information Center

    Green, Ravonne A.; Huprich, Julia

    2009-01-01

    Section 508 of the Americans with Disabilities Act (ADA) mandates that programs and services be accessible to people with disabilities. While schools of library and information science (SLIS*) and university libraries should model accessible Web sites, this may not be the case. This article examines previous studies about the Web accessibility of…

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

    NASA Technical Reports Server (NTRS)

    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.

  2. Influence of WC-Co substrate pretreatment on diamond film deposition by laser-assisted combustion synthesis.

    PubMed

    Veillère, Amélie; Guillemet, Thomas; Xie, Zhi Qiang; Zuhlke, Craig A; Alexander, Dennis R; Silvain, Jean-François; Heintz, Jean-Marc; Chandra, Namas; Lu, Yong Feng

    2011-04-01

    The quality of diamond films deposited on cemented tungsten carbide substrates (WC-Co) is limited by the presence of the cobalt binder. The cobalt in the WC-Co substrates enhances the formation of nondiamond carbon on the substrate surface, resulting in a poor film adhesion and a low diamond quality. In this study, we investigated pretreatments of WC-Co substrates in three different approaches, namely, chemical etching, laser etching, and laser etching followed by acid treatment. The laser produces a periodic surface pattern, thus increasing the roughness and releasing the stress at the interfaces between the substrate and the grown diamond film. Effects of these pretreatments have been analyzed in terms of microstructure and cobalt content. Raman spectroscopy was conducted to characterize both the diamond quality and compressive residual stress in the films. PMID:21462974

  3. Wolf-Rayet stars of type WN/WC and mixing processes during core helium burning of massive stars

    NASA Technical Reports Server (NTRS)

    Langer, N.

    1991-01-01

    Consequences of the recent finding that most WN/WC spectra probably originate from individual Wolf-Rayet stars for the internal structure of massive stars are discussed. Numerical models including the effect of slow-down or prevention of convective mixing due to molecular weight gradients are presented, in which a transition layer with a composition mixture of H- and He-burning ashes is formed above the convective He-burning core. These models are able to qualitatively account for the observed WN/WC frequency and agree quantitatively with the only WN/WC-composition determination so far. It is argued that the same transition layer may be responsible for the final blue loop which the SN 1987 A progenitor performed some 10,000 yr before explosion. These results indicate that composition barriers may be efficient in restricting convection during central helium burning, in contrast to computations relying on the Schwarzschild criterion for convection, with or without overshooting.

  4. Human cell line-dependent WC-Co nanoparticle cytotoxicity and genotoxicity: a key role of ROS production.

    PubMed

    Paget, V; Moche, H; Kortulewski, T; Grall, R; Irbah, L; Nesslany, F; Chevillard, S

    2015-02-01

    Although tungsten carbide-cobalt (WC-Co) nanoparticles (NPs) have been widely used because of their robustness, their risk to human health remains poorly studied, despite the International Agency for Research on Cancer (IARC) classifying them as "probably carcinogenic" for humans (Group 2A) in 2006. Our current study aimed at defining the cytotoxicity and genotoxicity of one set of commercially available 60-nm diameter WC-Co NPs on three human cell lines representative of potential target organs: A549 (lung), Hep3B (liver), and Caki-1 (kidney). The cytotoxicity of WC-Co NPs was determined by evaluating cell impedance (xCELLigence), cell survival/death, and cell cycle checkpoints. Flow cytometry was used to not only evaluate cell cycle checkpoints, but to also estimate reactive oxygen species (ROS) generation. In addition, γ-H2Ax foci detection (confocal microscopy), considered to be the most sensitive technique for studying DNA double-strand breaks, was utilized to evaluate genotoxicity. As a final part of this study, we assessed the cellular incorporation of WC-Co NPs, first byflow cytometry (side scatter), and then by confocal microscopy (light reflection) to ensure that the NPs had entered cells. Overall, our current findings demonstrate that WC-Co NPs induce cell mortality, DNA double-strand breaks, and cell cycle arrest in human renal (Caki-1) and liver (Hep3B) cell lines, but do not induce significant cytotoxic effects in A549 lung cells. Interestingly, although WC-Co NPs effectively entered the cells in all 3 lines tested, ROS were detected in Caki-1 and Hep3B, but not in A549. This may explain the great differences in the cytotoxic and genotoxic effects we observed between these lines. PMID:25398624

  5. 76 FR 255 - Airworthiness Directives; Pratt & Whitney Canada Corp. (P&WC) PW305A and PW305B Turbofan Engines

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-01-04

    ... 39-16524 (75 FR 72653, November 26, 2010), currently requires updating the airworthiness limitations section of the engine maintenance manuals for Pratt & Whitney Canada (P&WC) PW305A and PW305B turbofan... Canada Corp. (P&WC) PW305A and PW305B Turbofan Engines AGENCY: Federal Aviation Administration (FAA),...

  6. Where There Is No Toilet: Water and Sanitation Environments of Domestic and Facility Births in Tanzania

    PubMed Central

    Benova, Lenka; Cumming, Oliver; Gordon, Bruce A.; Magoma, Moke; Campbell, Oona M. R.

    2014-01-01

    Background Inadequate water and sanitation during childbirth are likely to lead to poor maternal and newborn outcomes. This paper uses existing data sources to assess the water and sanitation (WATSAN) environment surrounding births in Tanzania in order to interrogate whether such estimates could be useful for guiding research, policy and monitoring initiatives. Methods We used the most recent Tanzania Demographic and Health Survey (DHS) to characterise the delivery location of births occurring between 2005 and 2010. Births occurring in domestic environments were characterised as WATSAN-safe if the home fulfilled international definitions of improved water and improved sanitation access. We used the 2006 Service Provision Assessment survey to characterise the WATSAN environment of facilities that conduct deliveries. We combined estimates from both surveys to describe the proportion of all births occurring in WATSAN-safe environments and conducted an equity analysis based on DHS wealth quintiles and eight geographic zones. Results 42.9% (95% confidence interval: 41.6%–44.2%) of all births occurred in the woman's home. Among these, only 1.5% (95% confidence interval: 1.2%–2.0%) were estimated to have taken place in WATSAN-safe conditions. 74% of all health facilities conducted deliveries. Among these, only 44% of facilities overall and 24% of facility delivery rooms were WATSAN-safe. Combining the estimates, we showed that 30.5% of all births in Tanzania took place in a WATSAN-safe environment (range of uncertainty 25%–42%). Large wealth-based inequalities existed in the proportion of births occurring in domestic environments based on wealth quintile and geographical zone. Conclusion Existing data sources can be useful in national monitoring and prioritisation of interventions to improve poor WATSAN environments during childbirth. However, a better conceptual understanding of potentially harmful exposures and better data are needed in order to devise and apply

  7. Realization of the WC-C peritectic fixed point at NIM and NMIJ

    SciTech Connect

    Wang, T.; Bai, C.; Yuan, Z.; Dong, W.; Lu, X.; Sasajima, N.; Yamada, Y.; Ara, C.

    2013-09-11

    Three WC-C peritectic fixed point cells, constructed from different sources of tungsten with different nominal purities, were measured at NIM and NMIJ. The three cells were constructed at NMIJ by NIM and NMIJ staffs, and T{sub 90} values of the three cells were measured at NMIJ during the period 31 Aug. to 25 Dec. 2009. Thereafter, the three cells were then transported to NIM, and T{sub 90} values of these cells were measured from 7 Dec. 2011 to 9 Jan. 2012. The results showed that T{sub 90} values of the three cells measured at the two institutes agreed within 0.4 °C with the combined scale comparison uncertainty of 1.7 °C (k= 2). The main component of the uncertainty is not the uncertainty due to impurities of the cells but the scale uncertainty and the stability of the measurement system. From these results it can be concluded that the WC-C cell is stable enough to provide new means of international high-temperature scale comparison above 3000 K.

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

    NASA Astrophysics Data System (ADS)

    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.

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

    NASA Astrophysics Data System (ADS)

    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.

  10. Sliding and abrasive wear resistance of thermal-sprayed WC-CO coatings

    NASA Astrophysics Data System (ADS)

    Qiao, Yunfei; Liu, Yourong; Fischer, Traugott E.

    2001-03-01

    We studied the resistance of the coatings to abrasive and unlubricated sliding wear of 40 WC/Co coatings applied by high velocity oxygen fuel (HVOF), high-energy plasma spray (HEPS), and high velocity plasma spray (HVPS), using commercial and nanostructured experimental powders. The hardness of the coatings varies from 3 to 13 GPA, which is much lower than that of sintered samples (10 to 23 GPA) because of the porosity of the coatings. Phase analysis by x-ray diffraction revealed various amounts of decarburization in the coatings, some of which contain WC, W2C, W, and η phase. The abrasive and sliding wear resistance is limited by the hardness of the samples. For a given hardness, the wear resistance is lowered by decarburization, which produces a hard but brittle phase. Nanocarb powders have the shape of thin-walled hollow spheres that heat up rapidly in the gun and are more prone to decarburization than commercial materials. The work shows that, in order to obtain the performance of nanostructured coatings, the powder and spray techniques must be modified.

  11. Elastic-Plastic Constitutive Equation of WC-Co Cemented Carbides with Anisotropic Damage

    SciTech Connect

    Hayakawa, Kunio; Nakamura, Tamotsu; Tanaka, Shigekazu

    2007-05-17

    Elastic-plastic constitutive equation of WC-Co cemented carbides with anisotropic damage is proposed to predict a precise service life of cold forging tools. A 2nd rank symmetric tensor damage tensor is introduced in order to express the stress unilaterality; a salient difference in uniaxial behavior between tension and compression. The conventional framework of irreversible thermodynamics is used to derive the constitutive equation. The Gibbs potential is formulated as a function of stress, damage tensor, isotropic hardening variable and kinematic hardening variable. The elastic-damage constitutive equation, conjugate forces of damage, isotropic hardening and kinematic hardening variable is derived from the potential. For the kinematic hardening variable, the superposition of three kinematic hardening laws is employed in order to improve the cyclic behavior of the material. For the evolution equation of the damage tensor, the damage is assumed to progress by fracture of the Co matrix - WC particle interface and by the mechanism of fatigue, i.e. the accumulation of microscopic plastic strain in matrix and particles. By using the constitutive equations, calculation of uniaxial tensile and compressive test is performed and the results are compared with the experimental ones in the literature. Furthermore, finite element analysis on cold forward extrusion was carried out, in which the proposed constitutive equation was employed as die insert material.

  12. Fractal dimension and surface topography on the diamond deposition of seeded WC-Co substrates

    NASA Astrophysics Data System (ADS)

    Chou, C.-C.; Lin, H.-H.

    2010-04-01

    Diamond thin films were deposited on WC-Co substrates by hot filament chemical vapor deposition to improve the tribological performance. The influence of the substrate surface topography was found to play an important role during the nucleation stage and the later growth rate as well. In this study, we systematically investigated the relation between substrate surface irregularity, which was evaluated by fractal dimension as well as statistical roughness parameters and the quality of the later deposited diamond film. Preseeding processes, in diamond acetone suspensions with two particle diameters, by supersonic vibrator were also implemented to investigate the effect of particular size on diamond nucleation. The original surfaces were measured with a stylus profiler and contact-mode atomic force microscopy. The diamond deposited substrates were examined by scanning electron microscopy, x-ray diffractometry, Raman spectroscopy, and Rockwell-C indentation to study substrate topography, crystalline structure of the coating, the composition of diamond films, and adhesion between deposited layers and substrates, respectively. The synergetic influence of the substrate's fractal dimension and the particular size of pre-seeding diamond suspension were studied and addressed. The deposited film of a WC-Co substrate with higher surface fractal dimension (>2.50), preseeded by fine diamond suspension (4-12 nm particle size) in advance, has a high diamond-rich composition and adhesion strength.

  13. Elastic-Plastic Constitutive Equation of WC-Co Cemented Carbides with Anisotropic Damage

    NASA Astrophysics Data System (ADS)

    Hayakawa, Kunio; Nakamura, Tamotsu; Tanaka, Shigekazu

    2007-05-01

    Elastic-plastic constitutive equation of WC-Co cemented carbides with anisotropic damage is proposed to predict a precise service life of cold forging tools. A 2nd rank symmetric tensor damage tensor is introduced in order to express the stress unilaterality; a salient difference in uniaxial behavior between tension and compression. The conventional framework of irreversible thermodynamics is used to derive the constitutive equation. The Gibbs potential is formulated as a function of stress, damage tensor, isotropic hardening variable and kinematic hardening variable. The elastic-damage constitutive equation, conjugate forces of damage, isotropic hardening and kinematic hardening variable is derived from the potential. For the kinematic hardening variable, the superposition of three kinematic hardening laws is employed in order to improve the cyclic behavior of the material. For the evolution equation of the damage tensor, the damage is assumed to progress by fracture of the Co matrix — WC particle interface and by the mechanism of fatigue, i.e. the accumulation of microscopic plastic strain in matrix and particles. By using the constitutive equations, calculation of uniaxial tensile and compressive test is performed and the results are compared with the experimental ones in the literature. Furthermore, finite element analysis on cold forward extrusion was carried out, in which the proposed constitutive equation was employed as die insert material.

  14. Effect of Spray Parameters on the Corrosion Behavior of HVOF Sprayed WC-Co-Cr Coatings

    NASA Astrophysics Data System (ADS)

    Hong, Sheng; Wu, Yuping; Zheng, Yugui; Wang, Bo; Gao, Wenwen; Li, Gaiye; Ying, Guobing; Lin, Jinran

    2014-04-01

    WC-10Co-4Cr cermet coatings were deposited on the substrate of AISI 1045 steel by using high-velocity oxygen-fuel (HVOF) thermal spraying process. The Taguchi method including the signal-to-noise (S/N) ratio and the analysis of variance (ANOVA) was employed to optimize the porosity and, in turn, the corrosion resistance of the coatings. The spray parameters evaluated in this study were spray distance, oxygen flow, and kerosene flow. The results indicated that the important sequence of spray parameters on the porosity of the coatings was spray distance > oxygen flow > kerosene flow, and the spray distance was the only significant factor. The optimum spraying condition was 300 mm for the spray distance, 1900 scfh for the oxygen flow, and 6.0 gph for the kerosene flow. The results showed the significant influence of the microstructure on the corrosion resistance of the coatings. Potentiodynamic polarization and electrochemical impendence spectroscopy (EIS) results showed that the WC-10Co-4Cr cermet coating obtained by the optimum spraying condition with the lowest porosity exhibits the best corrosion resistance and seems to be an alternative to hard chromium coating.

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

    SciTech Connect

    Knudson, Marcus D.; Reinhart, William Dodd; Vogler, Tracy John; Root, Seth

    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.

  16. Pt catalysts on PANI coated WC/C nanocomposites for methanol electro-oxidation and oxygen electro-reduction in DMFC

    NASA Astrophysics Data System (ADS)

    Yaldagard, Maryam; Jahanshahi, Mohsen; Seghatoleslami, Naser

    2014-10-01

    In the present study a Pt/PANI/WC/C electrocatalyst was developed to increase the methanol electro-oxidation and oxygen electro-reduction activity and stability of commercial Pt/C electrocatalyst. WC/C was coated with protonated polyaniline (PANI) in situ during the polymerization of aniline. Fourier transform infrared (FTIR) results illustrate the presence of PANI in the composite. The conductivity of PANI coated - WC/C has been compared with the conductivity of the corresponding mixtures of WC/C and Vulcan XC-72. X-ray diffraction results showed that Pt particles were dispersed on the support with mean particle size of about 10.56 nm. Transition electron microscopy images showed that the nanosized WC/C were successfully coated by PANI. Based on the electrochemical properties characterized by cyclic voltammetry, CO stripping and rotating disk electrode measurements it was found that the as prepared Pt/PANI/WC/C electrocatalyst exhibited a comparable activity for methanol oxidation reaction and oxygen reduction reaction with respect to the commercial one. A significant reduction in the potential of CO electro-oxidation peak from 0.75 V for Pt/C to 0.52 V for Pt/PANI/WC/C electrocatalyst indicates that an increase in the activity for CO electro-oxidation is achieved by replacing the carbon support by PANI coated WC/C. Chronoamerometry results also showed, in the presence of methanol the Pt/PANI/WC/C electrocatalyst still maintains a higher current density than Pt/WC/C and Pt/C.

  17. Open Access

    ERIC Educational Resources Information Center

    Suber, Peter

    2012-01-01

    The Internet lets us share perfect copies of our work with a worldwide audience at virtually no cost. We take advantage of this revolutionary opportunity when we make our work "open access": digital, online, free of charge, and free of most copyright and licensing restrictions. Open access is made possible by the Internet and copyright-holder…

  18. Access Denied

    ERIC Educational Resources Information Center

    Villano, Matt

    2008-01-01

    Building access control (BAC)--a catchall phrase to describe the systems that control access to facilities across campus--has traditionally been handled with remarkably low-tech solutions: (1) manual locks; (2) electronic locks; and (3) ID cards with magnetic strips. Recent improvements have included smart cards and keyless solutions that make use…

  19. Synthesis of nanostructured WC-12 pct Co coating using mechanical milling and high velocity oxygen fuel thermal spraying

    SciTech Connect

    He, J. Ice, M.; Dallek, S.; Lavernia, E.J.

    2000-02-01

    A nanostructured WC-12 pct Co coating was synthesized using mechanical milling and high velocity oxygen fuel (HVOF) thermal spraying. The variation of powder characteristics with milling time and the performance of the coatings were investigated using scanning electron microscope (SEM), X-ray, transmission electron microscope (TEM), thermogravimetric analyzer (TGA), and microhardness measurements. There is no evidence that indicates the presence of an amorphous phase in the sintered WC-12 pct Co powder, and the binder phase in this powder is still crystalline Co. Mechanical milling of up to 20 hours did not lead to the formation of an amorphous phase in the sintered WC-12 pct Co powder. During the initial stages of the milling, the brittle carbide particles were first fractured into fragments and then embedded into the binder phase. This process gradually formed polycrystal nanocomposite powders of the Co binder phase and W carbide particles. The conventional cold welding and fracturing processes primarily occurred among the Co binder powders and polycrystal composite powders. The nanostructured WC-12 pct Co coatings, synthesized in the present study, consist of an amorphous matrix and carbides with an average particle diameter of 35 nm. The coating possesses an average microhardness of 1135 HV and higher resistance to indentation fracture than that of its conventional counterpart.

  20. Semi-automated structural characterisation of high velocity oxy fuel thermally sprayed WC-Co based coatings

    NASA Astrophysics Data System (ADS)

    Fay, M. W.; Han, Y.; McCartney, G.; Korpiola, K.; Brown, P. D.

    2008-08-01

    The application of an automated procedure for the rapid assessment of selected area electron diffraction patterns is described. Comparison with complementary EDX spectra has enabled the thermal decomposition reactions within high velocity oxy-fuel thermally sprayed WC-Co coatings to be investigated.

  1. Effects of Particle Strength of Feedstock Powders on Properties of Warm-Sprayed WC-Co Coatings

    NASA Astrophysics Data System (ADS)

    Chivavibul, Pornthep; Watanabe, Makoto; Kuroda, Seiji; Kawakita, Jin; Komatsu, Masayuki; Sato, Kazuto; Kitamura, Junya

    2011-09-01

    Warm spray (WS) process, which can control the temperature of a combustion gas jet used to propel powder, has been successfully applied to deposit WC-Co coatings. Detrimental reactions resulting from dissolution of WC into Co binder and decarburization were suppressed effectively by keeping the WC-Co particles' temperature below the m.p. of the binder phase. In this study, three nano-structured WC-12Co powders with different particle strengths were prepared by changing the sintering conditions of spray-dried powder and were deposited by WS. The deposition efficiency and porosity of the coatings decreased with increasing the particle strength. The coating deposited from the powder with very low particle strength showed significant phase changes, while those deposited from the higher particle strengths showed almost no change. Particle Image Velocimetry revealed significant disintegration of the weakest powder, which explains the changes observed. The hardness and wear properties of the former coating, therefore, were inferior to the other two.

  2. Microstructural study of MMC layers produced by combining wire and coaxial WC powder feeding in laser direct metal deposition

    NASA Astrophysics Data System (ADS)

    Li, Fuquan; Gao, Zhenzeng; Li, Liqun; Chen, Yanbin

    2016-03-01

    Combined wire and powder deposition by laser (WPDL) has proven to be a promising method for fabricating Metal Matrix Compounds (MMC). Here we demonstrate the deposition of a MMC layer onto Ti6Al4V substrate by WPDL. WC powder was fed from a coaxial nozzle whilst titanium wire was fed from a lateral nozzle into a laser generated melt pool. The appearance of the MMC layer was controlled by process parameters including wire feeding rate, powder feeding rate and laser power. The microstructure of these compound layers were subsequently analyzed by SEM, EDS and XRD. It has shown that compound layer are comprised of α-Ti, WC, W2C, TiC, W and (W,Ti) C1-x phase. The W2C phase and TiC phase was formed and distributed in titanium matrix with different shape at the different location of MMC layer. WC particles were distributed throughout the MMC layer as enforcement phase, which occurring metallic bonding with matrix. The presence of WC and TiC phase in the MMC layer enhanced its microhardness and abrasive.

  3. WC Nanocrystals Grown on Vertically Aligned Carbon Nanotubes: An Efficient and Stable Electrocatalyst for Hydrogen Evolution Reaction.

    PubMed

    Fan, Xiujun; Zhou, Haiqing; Guo, Xia

    2015-05-26

    Single nanocrystalline tungsten carbide (WC) was first synthesized on the tips of vertically aligned carbon nanotubes (VA-CNTs) with a hot filament chemical vapor deposition (HF-CVD) method through the directly reaction of tungsten metal with carbon source. The VA-CNTs with preservation of vertical structure integrity and alignment play an important role to support the nanocrystalline WC growth. With the high crystallinity, small size, and uniform distribution of WC particles on the carbon support, the formed WC-CNTs material exhibited an excellent catalytic activity for hydrogen evolution reaction (HER), giving a η10 (the overpotential for driving a current of 10 mA cm(-2)) of 145 mV, onset potential of 15 mV, exchange current density@ 300 mV of 117.6 mV and Tafel slope values of 72 mV dec(-1) in acid solution, and η10 of 137 mV, onset potential of 16 mV, exchange current density@ 300 mV of 33.1 mV and Tafel slope values of 106 mV dec(-1) in alkaline media, respectively. Electrochemical stability test further confirms the long-term operation of the catalyst in both acidic and alkaline media. PMID:25869150

  4. Determination and modeling of residual stress in functionally graded WC-Co

    NASA Astrophysics Data System (ADS)

    Tahvilian, Leila

    Gradual variations in composition and/or structure through the volume of functionally graded materials (FGMs) generally result in corresponding continuous spatial variations in mechanical/physical properties, and often in significant residual stresses that develop during processing. Due to inhomogeneous properties in these materials, residual stress measurement in FGMs can be a very challenging problem. In this study, residual stresses in functionally graded cemented tungsten carbide (FG-WC-Co) were investigated by numerical, analytical and experimental approaches by means of a layer removal technique. The numerical method consisted of finite element analysis (FEA) modeling for the FGM plate, in order to calculate residual stress distribution over the volume and to develop a method for predicting residual stress levels in closely related materials. The analytical procedure embodied a mathematical approach to determine residual stress distributions, and analytically determined values are compared with those obtained from FEA modeling and experimental results. The experimental approach consisted of fabricating and heat treating FG-WC-Co flat samples, then measuring strain changes by strain gauge after each sequential layer removal from the opposite side of the specimen from the graded region. Good agreement was found between analytical, numerical and experimental results. Furthermore, thermal residual stress distribution in FG-WC-Co hollow cylinder was examined with an emphasis on the effects of key variables, the gradient profile and the gradient thickness, on the magnitude and distribution of the stress field. An analytical direct solution based on solving the governing equations of a cylinder composed of a uniform inner core and a functionally graded outer shell was developed. The cylindrical compound was considered as two separate elements: homogeneous cylinder and functionally graded shell. Material properties, such as the elastic modulus and the coefficient of

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

    NASA Astrophysics Data System (ADS)

    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.

  6. A comparative study on wear behavior of TiN and diamond coated WC-Co substrates against hypereutectic Al-Si alloys

    NASA Astrophysics Data System (ADS)

    Chakravarthy, G. V.; Chandran, Maneesh; Bhattacharya, S. S.; Rao, M. S. Ramachandra; Kamaraj, M.

    2012-11-01

    The demand for better tools for machining hypereutectic aluminum-silicon (Al-Si) alloys are increasing day by day since the extensive use of these alloys in internal combustion engines. In addition to the lifetime of the machining tool, surface finish of the machined piece is also equally important, as it directly affects the performance of the engine. In this paper, we compared the wear behavior of bare tungsten carbide (WC-Co), titanium nitride (TiN) coated WC-Co and diamond coated WC-Co substrates against Al-Si alloys using pin-on-disc method. Both TiN and diamond coatings were done using chemical vapor deposition technique. Diamond coated WC-Co substrates show one order less wear loss compared to the bare WC-Co substrates. Instead of weight loss, a weight gain was observed for the TiN coated WC-Co substrates. Average coefficient of friction was lowest for the diamond coated WC-Co substrates due to the different wear behavior of diamond coated tribological system, which is explained in detail.

  7. Thermal interaction between WC-Co coating and steel substrate in process of HVOF spraying

    SciTech Connect

    Guilemany, J.M.; Sobolev, V.V.; Nutting, J.; Dong, Z.; Calero, J.A. . Metalurgia Fisica-Ciencia de Materials)

    1994-10-01

    The WC-Co powders can be used to produce good adhesive and wear resistant HVOF thermal spray coatings on steel and light alloys substrates. In order to understand the properties of this kind of coating, the phases which are present in the coatings and structure changes during post heat treatments have been investigated. Although the coating properties depend very much on the structure developed in the substrate-coating interfacial region it has not been yet investigated in detail. The present study is devoted to the experimental and theoretical analysis of this interfacial region. The structure characterization has been performed mainly through the use of transmission electron microscopy. To provide a theoretical investigation a realistic prediction model of the process has been developed and on its base the mathematical simulation of the substrate-coating thermal interaction has been undertaken.

  8. Erosion Resistance of High Velocity Oxy-Fuel WC-Co-Cr Thermal Spray Coatings

    NASA Astrophysics Data System (ADS)

    Imeson, Chris

    Thermal spray coatings have been incorporated in oil and gas extraction efforts for many years. Recently, High Velocity Oxy-Fuel (HVOF) has become increasingly incorporated where erosive environments are present. This study investigates the microstructural and mechanical properties of HVOF WC-Co-Cr coatings deposited at SharkSkin Coatings ltd. The deposited coatings exhibited a low porosity with high adhesion strength, hardness, and superior erosion resistance. In this study, a recirculating solid particle erosion testing machine was designed and fabricated to simulate an erosive environment on a laboratory scale. This study was also aimed at improving microstructures and mechanical properties of the coatings by modifying the two coating deposition parameters e.g. standoff and pre-cycle heating. It was determined that pre-spray substrate heating negatively affected the coatings microstructures e.g. porosity, while reducing the stand-off distance positively influenced the coating microstructures and mechanical properties, e.g. erosion resistance.

  9. EBSD characterization of carbide-carbide boundaries in WC-Co composites.

    PubMed

    Farooq, M U; Klement, U

    2004-03-01

    A sample of WC-6wt%Co was investigated for grain boundary character distribution and occurrence of coincidence site lattice (CSL) boundaries on a statistical basis. For this purpose orientation measurements of the grains were carried out using electron back-scattered diffraction (EBSD). The dominant misorientation relationships were determined by complementary EBSD data representation tools such as orientation maps, misorientation angle distribution histograms and the sectioned three-dimensional misorientation space. It was found that the grain boundary character distribution of the material is nearly random and the CSL boundaries are not present in statistically significant amounts. It was also found that the amount of binder phase does not play a role in the formation of special boundaries. The paper focuses on the methodology of characterizing grain boundaries in a hexagonal material using EBSD. PMID:15009698

  10. Atomic structure of the Σ = 2 twist carbide grain boundary in WC-Co alloys

    NASA Astrophysics Data System (ADS)

    Lay, Sabine; Missiaen, Jean-Michel

    2013-04-01

    The Σ = 2 twist carbide grain boundary with a (10 ? 0) habit plane was investigated by high resolution transmission electron microscopy in a WC-Co alloy. The atomic structure at the boundary was determined by comparing experimental images and simulations. It corresponds to the boundary model with the lowest energy according to atomistic calculations. Periodic monolayer interfacial steps, compensating for the parametric misfit at the boundary were studied. The displacement field around the defects was simulated and corresponds to a dislocation with a mixed character and a Burgers vectors equal to 1/6⟨ ? 2 ? 3⟩ lying in the boundary plane. Another step with a larger height and connected to a stacking fault was analyzed. It likely arises from the interaction of a matrix dislocation with the boundary. The observations suggest that the migration of Σ = 2 grain boundaries can be induced by the glide of the monolayer steps along the grain boundary.

  11. Microstructure and properties of (Ti, Al) N coatings on WC-Co cemented carbide

    NASA Astrophysics Data System (ADS)

    Li, Yudong; Liu, Zhen; Yang, Jing; Chen, Yigang

    2013-03-01

    (Ti, Al)N films were grown on WC-Co cemented carbides by R.F. reactive sputtering using Ti/Al composite target. The crystalline structure, morphology and composition of (Ti, Al)N coatings were investigated by X-ray diffraction (XRD), optical microscope and X-ray energy dispersive spectroscope (EDS), respectively. The mechanical properties of (Ti, Al)N coatings with the variable Al content were investigated by applying nanoindentation. With the increase of the Al content, the crystal structure of (Ti, Al)N films changed from fcc to hexagonal structure. When the ratio of Ti to Al in (Ti, Al)N coatings was approximately 4:1, and the N content was 40.67 %, the nano-hardness of (Ti, Al)N coating was highly up to 28 GPa. By adjusting the Al content, the lowest value of friction coefficients was 0.1397.

  12. Tribological behavior of NiTi alloy against 52100 steel and WC at elevated temperatures

    SciTech Connect

    Abedini, M.; Ghasemi, H.M.; Ahmadabadi, M. Nili

    2010-07-15

    The dry tribological behavior of a Ti-50.3 at.% Ni alloy at temperatures of 25 deg. C, 50 deg. C and 200 deg. C was studied. The wear tests were performed on a high temperature pin-on-disk tribometer using 52100 steel and tungsten carbide pins. The worn surfaces of the NiTi alloy were examined by scanning electron microscope. The results showed that in the wear tests involving steel pins, the wear rate of the NiTi decreased as the wear testing temperature was increased. However, for the NiTi/WC contact, a reverse trend was observed. There was also a large decrease in the coefficient of friction for the NiTi/steel contact with increasing wear testing temperature. The formation of compact tribological layers could be the main reason for the reduction of the wear rate and coefficient of friction of the NiTi/steel contact at higher wear testing temperatures.

  13. Ammonia decomposition activity on monolayer Ni supported on Ru, Pt and WC substrates

    NASA Astrophysics Data System (ADS)

    Hansgen, Danielle A.; Vlachos, Dionisios G.; Chen, Jingguang G.

    2011-12-01

    Catalyst design for specific reactions currently involves using atomic or molecular descriptors to identify promising catalysts. In this paper, we explore three surfaces that have similar computed nitrogen binding energies, which is a descriptor for the ammonia decomposition reaction. The surfaces studied include a monolayer of Ni on Pt(111), Ru(0001) and tungsten monocarbide (WC). The activity of these surfaces toward the ammonia decomposition reaction was compared using density functional theory and temperature programmed desorption. It was found that while the NHx-H bond scission is similar on each of the surfaces, the temperature of nitrogen desorption is very different. The differences are explained and the implications for ammonia decomposition activity and catalyst design are discussed.

  14. Hard-metal (WC-Co) particles trigger a signaling cascade involving p38 MAPK, HIF-1α, HMOX1, and p53 activation in human PBMC.

    PubMed

    Lombaert, Noömi; Castrucci, Eleonora; Decordier, Ilse; Van Hummelen, Paul; Kirsch-Volders, Micheline; Cundari, Enrico; Lison, Dominique

    2013-02-01

    Hard-metals are made of tungsten carbide (WC) and metallic cobalt (Co) particles and are important industrial materials produced for their extreme hardness and high wear resistance properties. While occupational exposure to metallic Co alone is apparently not associated with an increased risk of cancer, the WC-Co particle mixture was shown to increase the risk of lung cancer in exposed workers. We have previously shown that WC-Co specifically induces a burst of reactive oxygen species (ROS) and in vitro mutagenic/apoptogenic effects in human peripheral blood mononucleated cells (PBMC) used as a validated experimental model. In the present study, PBMCs were treated during a short period (15 min) to focus on the very rapid ROS burst induced by WC-Co. We investigated by microarray the response to WC-Co versus Co(2+) ions (CoCl(2)) after 15 min exposure and found that the oxidative stress response HMOX1 gene was highly expressed in WC-Co-treated samples. This result was confirmed by qRT-PCR, and western blotting was carried out to analyze translational and post-translational regulation of genes belonging to the HMOX1 pathway. We show here that WC-Co, and metallic Co particles although with slower kinetics, but not CoCl(2) or WC alone, induced a temporally ordered cascade of events. This cascade implies p38/MAP kinase activation, HIF-1α stabilization, HMOX1 transcriptional activation, and ATM-independent p53 stabilization. These events, and in particular HIF-1α stabilization, could contribute to the carcinogenic activity of WC-Co dusts. PMID:23052192

  15. Time-Resolved FUSE Spectroscopy of the LMC WC + O Binaries Br 22 and Br 32

    NASA Astrophysics Data System (ADS)

    Boisvert, Philippe; Marchenko, Sergey V.; St-Louis, Nicole; Moffat, Anthony F. J.

    2008-08-01

    Using the Far Ultraviolet Spectroscopic Explorer satellite, we obtained series of spectra for two of the three known WC + O binaries in the LMC, Br 22, and Br 32 (HD 36521). Compared to Br 22, we detect a higher ratio of C IV to He II lines in Br 32, which could indicate a more advanced evolutionary stage for the latter. The orbit of the O star in Br 32 has been determined from its P V absorption lines. We find that continuum fluxes in both systems are substantially diluted by a third-light source. The maximum extension of the black absorption troughs in P Cygni profiles provides the terminal velocities of the WC winds: 3775 +/- 125 km s-1 for Br 22 and 4400 +/- 150 km s-1 for Br 32. From the phase-dependent displacements of the blue absorption edges of prominent emission lines we estimate the half-opening angles of the wind-wind collision zones and their Coriolis deflections. In both binaries we fitted, via iterative procedure, the phase-dependent changes in the O VI λ1032-1037 and C III λ1175 profiles as a function of the wind, stellar, and orbital parameters. This allowed us to isolate the excess emission produced in the wind-wind collision zone and reproduce profile changes caused by atmospheric eclipses. A strong extra emission component is observed in Br 22 (P = 14.9 days), while it is negligible in Br 32 (P = 1.9 days). Based on observations made with the NASA-CNES-CSA Far Ultraviolet Spectroscopic Explorer (FUSE). FUSE is operated for NASA by The Johns Hopkins University under NASA contract NAS5-32985.

  16. Thermoanaerobacter thermohydrosulfuricus WC1 Shows Protein Complement Stability during Fermentation of Key Lignocellulose-Derived Substrates

    PubMed Central

    Verbeke, Tobin J.; Spicer, Vic; Krokhin, Oleg V.; Zhang, Xiangli; Schellenberg, John J.; Fristensky, Brian; Wilkins, John A.; Levin, David B.

    2014-01-01

    Thermoanaerobacter spp. have long been considered suitable Clostridium thermocellum coculture partners for improving lignocellulosic biofuel production through consolidated bioprocessing. However, studies using “omic”-based profiling to better understand carbon utilization and biofuel producing pathways have been limited to only a few strains thus far. To better characterize carbon and electron flux pathways in the recently isolated, xylanolytic strain, Thermoanaerobacter thermohydrosulfuricus WC1, label-free quantitative proteomic analyses were combined with metabolic profiling. SWATH-MS proteomic analysis quantified 832 proteins in each of six proteomes isolated from mid-exponential-phase cells grown on xylose, cellobiose, or a mixture of both. Despite encoding genes consistent with a carbon catabolite repression network observed in other Gram-positive organisms, simultaneous consumption of both substrates was observed. Lactate was the major end product of fermentation under all conditions despite the high expression of gene products involved with ethanol and/or acetate synthesis, suggesting that carbon flux in this strain may be controlled via metabolite-based (allosteric) regulation or is constrained by metabolic bottlenecks. Cross-species “omic” comparative analyses confirmed similar expression patterns for end-product-forming gene products across diverse Thermoanaerobacter spp. It also identified differences in cofactor metabolism, which potentially contribute to differences in end-product distribution patterns between the strains analyzed. The analyses presented here improve our understanding of T. thermohydrosulfuricus WC1 metabolism and identify important physiological limitations to be addressed in its development as a biotechnologically relevant strain in ethanologenic designer cocultures through consolidated bioprocessing. PMID:24362431

  17. An IRAS-based search for new Dusty Late-Type WC Wolf-Rayet stars

    NASA Technical Reports Server (NTRS)

    Cohen, Martin

    1995-01-01

    I have examined all Infrared Astronomical Satellite (IRAS) data relevant to the 173 Galactic Wolf-Rayet (W-R) stars in an updated catalog, including the 13 stars newly discovered by Shara and coworkers. Using the W-R coordinates in these lists, I have examined the IRAS Point Source Catalog (PSC), the Faint Source Catalog, and the Faint Source Reject Catalog, and have generated one-dimensional spatial profiles ('ADDSCANs') and two-dimensional full-resolution images ('FRESCOs'). The goal was to assemble the best set of observed IRAS color indices for different W-R types, in particular for known dusty late-type WC Wolf-Rayet (WCL) objects. I have also unsuccessfully sought differences in IRAS colors and absolute magnitudes between single and binary W-R stars. The color indices for the entire ensemble of W-R stars define zones in the IRAS color-color plane. By searching the PSC for otherwise unassociated sources that satisfy these colors, I have identified potential new W-R candidates, perhaps too faint to have been recognized in previous optical searches. I have extracted these candidates' IRAS low-resolution spectrometer (LRS) data and compared the spectra with the highly characteristic LRS shape for known dusty WCL stars. The 13 surviving candidates must now be examined by optical spectroscopy. This work represents a much more rigorous and exhaustive version of the LRS study that identified IRAS 17380 - 3031 (WR98a) as the first new W-R (WC9) star discovered by IRAS. This search should have detected dusty WCL stars to a distance of 7.0 kpc from the Sun, for the absolute value of l greater than 30 deg, and to 2.9 kpc even in the innermost Galaxy. For free-free-dominated W-R stars the corresponding distances are 2.5 and 1.0 kpc, respectively.

  18. An IRAS-Based Search for New Dusty Late-Type WC Wolf-Rayet Stars

    NASA Technical Reports Server (NTRS)

    Cohen, Martin

    1995-01-01

    I have examined all Infrared Astronomical Satellite (IRAS) data relevant to the 173 Galactic Wolf-Rayet (W-R) stars in an updated catalog, including the 13 stars newly discovered by Shara and coworkers. Using the W-R coordinates in these lists, I have examined the IRAS Point Source Catalog (PSC), the Faint Source Catalog, and the Faint Source Reject Catalog, and have generated one-dimensional spatial profiles, 'ADDSCANs', and two-dimensional full-resolution images, 'FRESCOS'. The goal was to assemble the best set of observed IRAS color indices for different W-R types, in particular for known dusty late-type WC Wolf-Rayet (WCL) objects. I have also unsuccessfully sought differences in IRAS colors and absolute magnitudes between single and binary W-R stars. The color indices for the entire ensemble of W-R stars define zones in the IRAS color-color ([12] - [25], [25] - [60])-plane. By searching the PSC for otherwise unassociated sources that satisfy these colors, I have identified potential new W-R candidates, perhaps too faint to have been recognized in previous optical searches. I have extracted these candidates' IRAS low-resolution spectrometer (LRS) data and compared the spectra with the highly characteristic LRS shape for known dusty WCL stars. The 13 surviving candidates must now be ex amined by optical spectroscopy. This work represents a much more rigorous and exhaustive version of the LRS study that identified IRAS 17380 - 3031 (WR98a) as the first new W-R (WC9) star discovered by IPAS. This search should have detected dusty WCL stars to a distance of 7.0 kpc from the Sun, for l is greater than 30 degrees, and to 2.9 kpc even in the innermost galaxy. For free-free-dominated W-R stars the corresponding distances are 2.5 and 1.0 kpc, respectively.

  19. Action memorandum for the Waste Area Grouping 1 Tank WC-14 removal action at Oak Ridge National Laboratory, Oak Ridge, Tennessee

    SciTech Connect

    1994-11-01

    This action memorandum documents approval for a Comprehensive Environmental Response, Compensation, and Liability Act of 1980, as amended (CERCLA), time-critical action. The action will remove radiologically contaminated water from Tank WC-14. The water contains a polychlorinated biphenyl (PCB) at a level below regulatory concern. Tank WC-14 is located in the Waste Area Grouping (WAG) 1 WC-10 Tank Farm at the Oak Ridge National Laboratory (ORNL), Oak Ridge, Tennessee. Contaminated sludge remaining in the tank after removal of the liquid will be the subject of a future action.

  20. Microbiological assessments of compost toilets: in situ measurements and laboratory studies on the survival of fecal microbial indicators using sentinel chambers.

    PubMed

    Tønner-Klank, L; Møller, J; Forslund, A; Dalsgaard, A

    2007-01-01

    Compost toilet systems were assessed for their ability to reduce microbial indicators and pathogens. Bacterial pathogens were not detected in any samples indicating a low survival rate in composting feces and/or an initial low occurrence. Indicator bacteria showed large variations with no clear trend of lower bacterial numbers after longer storage. In controlled composting experiments, thermophilic conditions were only reached when amendments were made (grass and a sugar solution). Even then it was impossible to ensure a homogenous temperature in the composting fecal material and therefore difficult to achieve a uniform reduction and killing of indicator organisms. Presumptive thermotolerant coliforms, Salmonella typhimurium Phage 28 B and eggs of Ascaridia galli, proved useful as indicators. However, regrowth was detected for enterococci and total numbers of bacteria grown at 36 degrees C. These indicator parameters may therefore overestimate the level of other (pathogenic) bacteria present in the material and can not be recommended for use as reliable indicator organisms in composting toilet systems. The addition of indicator bacteria to fecal material contained in semi-permeable capsules proved to be a useful technique to ensure that microorganisms were contained in a small test volume. PMID:16908129

  1. Extracorporeal membrane oxygenation and toilet bronchoscopy as a bridge to pneumonectomy in severe community-acquired methicillin-resistant Staphylococcus aureus pneumonia

    PubMed Central

    Panchabhai, Tanmay S.; Khabbaza, Joseph E.; Raja, Siva; Mehta, Atul C.; Hatipoğlu, Umur

    2015-01-01

    Community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) pneumonia is associated with very high mortality. Though surgical evacuation of necrotic tissue is desirable in patients unresponsive to antimicrobial therapy, most patients are acutely ill precluding surgical intervention. We utilized a combination of extracorporeal membrane oxygenation (ECMO) with frequent toilet bronchoscopies to salvage an unaffected right lung from spillage of necrotic pus from left lung cavitary CA-MRSA pneumonia in a 22-year-old patient. Our patient while on ECMO and after decannulation was positioned with the right lung up at all times with 1-2 toilet bronchoscopies every day for almost 30 days. This time was utilized for ventilator weaning and optimizing the nutritional status prior to extrapleural left pneumonectomy. Prevention of soilage of the unaffected right lung and mitigating volutrauma with ECMO support combined with the subsequent surgical evacuation of necrotic left lung tissue led to a favorable outcome in this case. This strategy could be of value in similar presentations of unilateral suppurative pneumonia, where the progressive disease occurs despite optimal medical therapy. PMID:26664570

  2. Toilet Teaching Your Child

    MedlinePlus

    ... KidsHealth in the Classroom What Other Parents Are Reading Upsetting News Reports? What to Say Vaccines: Which ... child small rewards, such as stickers or time reading with Mommy, every time your child goes in ...

  3. Toilet Training Your Child

    MedlinePlus

    ... to be present when you go to the bathroom and make your child feel comfortable in the bathroom. Allow your child to see urine and bowel ... begin teaching your child to go to the bathroom. Keep your child in loose, easily removable pants. ...

  4. HuDo 1 and HuBi 1: two planetary nebulae ionized by cool [WC] central stars

    NASA Astrophysics Data System (ADS)

    Peña, M.

    2005-10-01

    As part of our spectroscopic survey of planetary nebulae with [WC] nuclei (Peña et al. 2001), low- and high-resolution spectra of the planetary nebulae HuDo 1 (PNG 060.4+01.5, PM1-310) and HuBi 1 (PNG 012.2+04.9, PM1-188) were secured and analyzed. Both objects are ionized by very late [WC] central stars. We found that the objects belong to the galactic disk, with heliocentric radial velocities of -12 km s-1 (HuDo 1) and 57 km s-1 (HuBi1). Both objects are heavily extinguished showing a logarithmic reddening, c(Hβ), of 2.04 for HuDo 1 and 1.22 for HuBi 1. Our data cover a wide wavelength range; therefore we obtained several plasma line ratios to estimate physical conditions and abundances. The derived electron temperature and density for HuBi 1 are 9,400±1,500 K and 800 cm-3. This density is very low for a nebula around a [WC]-late star. HuDo 1 has Ne = 3300 cm-3. We find log(O/H)+12 = 8.43 and 8.57, and N/O = 0.2 and 0.1 for HuDo 1 and HuBi 1 respectively, typical of disk PNe. Intense nebular He I recombination lines are detected for HuBi 1, this being the only PN excited by a very late [WC] star showing such an emission. The He+ abundance derived for HuBi 1 is 0.11, which is indicating a large He enhancement in HuBi 1. >From the analysis of the stellar emission lines a [WC 10] spectral type is derived for both stars. This is consistent with a stellar temperature of about 30,000 K, although the HuBi 1 central star should be slightly hotter for providing the large amount of He0 ionizing photons required to explain the nebular He I lines. Nebular and stellar parameters of HuDo 1 and HuBi 1 can be compared with those of other [WC 10] objects, such as M 4-18, He 2-113 and CPD-5608031. >From this, we can conclude that, in spite of the fact that all the objects have the same spectral type, the central stars of HuDo 1 and HuBi 1 should be intrinsically fainter, and consequently of lower mass. This is an additional evidence showing that stars of different masses can go

  5. Hemodialysis access - self care

    MedlinePlus

    Kidney failure - chronic-hemodialysis access; Renal failure - chronic-hemodialysis access; Chronic renal insufficiency - hemodialysis access; Chronic kidney failure - hemodialysis access; Chronic renal failure - hemodialysis access; dialysis - hemodialysis access

  6. Hemodialysis access - self care

    MedlinePlus

    Kidney failure - chronic-hemodialysis access; Renal failure - chronic-hemodialysis access; Chronic renal insufficiency - hemodialysis access; Chronic kidney failure - hemodialysis access; Chronic renal failure - ...

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

    NASA Astrophysics Data System (ADS)

    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.

  8. Expanding Access

    ERIC Educational Resources Information Center

    Roach, Ronald

    2007-01-01

    There is no question that the United States lags behind most industrialized nations in consumer access to broadband Internet service. For many policy makers and activists, this shortfall marks the latest phase in the struggle to overcome the digital divide. To remedy this lack of broadband affordability and availability, one start-up firm--with…

  9. Access Denied

    ERIC Educational Resources Information Center

    Raths, David

    2012-01-01

    As faculty members add online and multimedia elements to their courses, colleges and universities across the country are realizing that there is a lot of work to be done to ensure that disabled students (and employees) have equal access to course material and university websites. Unfortunately, far too few schools consider the task a top priority.…

  10. Easy Access

    ERIC Educational Resources Information Center

    Gettelman, Alan

    2009-01-01

    School and university restrooms, locker and shower rooms have specific ADA accessibility requirements that serve the needs of staff, students and campus visitors who are disabled as a result of injury, illness or age. Taking good care of them is good for the reputation of a sensitive community institution, and fosters positive public relations.…

  11. First-principles study of an interfacial phase diagram in the V-doped WC-Co system

    NASA Astrophysics Data System (ADS)

    Johansson, S. A. E.; Wahnström, G.

    2012-07-01

    We present a method of determining an interfacial phase diagram using density functional theory calculations for interface energetics. Cluster expansions based on these calculations are used in Monte Carlo simulations to obtain configurational free energies. The method is applied to study the segregation of V to the WC(0001)/Co interface and to construct the corresponding interface diagram, a “complexion” phase diagram. By CALPHAD-type analysis for the adjoining bulk phases, a connection with real materials is made. We find that, in equilibrium, the interface contains a thin V-rich film for a wide range of temperatures and chemical potentials of V corresponding to V additions below the (V,W)Cx solubility limit. The results are compared with available experimental data, and implications of the strong segregation of V for the sintering process of V-doped WC-Co are discussed.

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

    NASA Astrophysics Data System (ADS)

    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.

  13. The Structure and Bond Strength of Composite Carbide Coatings (WC-Co + Ni) Deposited on Ductile Cast Iron by Thermal Spraying

    NASA Astrophysics Data System (ADS)

    Ksiazek, Marzanna; Boron, Lukasz; Radecka, Marta; Richert, Maria; Tchorz, Adam

    2016-02-01

    An investigation was conducted to determine the role of Ni particles in the WC-Co coating produced with the supersonic method on microstructure, mechanical, and wear properties in a system of type: WC-Co coating/ductile cast iron. The microstructure of the thermal-sprayed WC-Co + Ni coating was characterized by scanning electron and transmission electron microscopes as well as the analysis of chemical and phase composition in microareas (EDS, XRD). The microstructure of the WC-Co + Ni coating consisted of large, partially molten Ni particles and very fine grains of WC embedded in cobalt matrix, coming to the size of nanocrystalline. Moreover, the results were discussed in reference to examination of bending strength considering cracking and delamination in the system of (WC-Co + Ni)/ductile cast iron as well as hardness and wear resistance of the coating. It was found that the addition of Ni particles was significantly increase resistance to cracking and wear behavior in the studied system.

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

    PubMed

    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. PMID:26476643

  15. Influence of process parameter variation on the reflectivity of sputter-deposited W-C multilayer diffraction gratings

    NASA Technical Reports Server (NTRS)

    Sager, B.; Benson, P.; Jahoda, K.; Jacobs, J. R.; Bloch, J. J.

    1986-01-01

    Multilayer W-C diffraction gratings with nominal d spacings of 35 A have been fabricated by magnetron sputter deposition. The peak and integrated reflectivities of these films have been measured with Al K-alpha X-rays and compared to theoretical values. The rms surface roughness has been evaluated. The influence of several sputtering-system process parameters on the reflectivities has been investigated.

  16. Cracking and Spalling Behavior of HVOF Thermally Sprayed WC-Co-Cr Coating in Bend and Axial Fatigue Tests

    NASA Astrophysics Data System (ADS)

    Gui, M.; Eybel, R.; Asselin, B.; Monerie-Moulin, F.

    2015-03-01

    In this work, WC-10Co-4Cr coating was sprayed by high-velocity oxygen fuel (HVOF) process on Almen strip and axial fatigue coupon. Three-point bend test was used to bend Almen strip coating specimens with tensile and compressive stress applied to the coating. Axial fatigue coating specimens were tested at a load stress of 1250 MPa and a stress ratio of R = -1. Process condition of Thermal spraying was found to have an effect on spalling performance of the coating in the fatigue test. The mechanism of cracking and spalling process in the coating was studied in bend and fatigue conditions. Based on deformation difference between the coating and the substrate, the factors, especially coating thickness, to impact the coating spalling behavior in axial fatigue test are discussed. HVOF-sprayed WC-10Co-4Cr coating matches the deformation of base substrate by cracking when tensile stress is applied in bend and fatigue tests because the coating has very limit deformation capability. In axial fatigue test of WC-10Co-4Cr coating specimen, the substrate works in a stress-to-strain manner; however the coating works in a strain-to-stress manner and is stressed due to the substrate deformation.

  17. Sliding and Rolling Wear Behavior of HVOF-Sprayed Coatings Derived from Conventional, Fine and Nanostructured WC-12Co Powders

    NASA Astrophysics Data System (ADS)

    Tillmann, W.; Baumann, I.; Hollingsworth, P. S.; Hagen, L.

    2014-01-01

    Fine structured and nanostructured materials represent a promising class of feedstock for future applications, which has also attracted increasing interest in the thermal spray technology. Within the field of wear protection, the application of fine structured or nanostructured WC-Co powders in the High Velocity Oxy-Fuel flame spraying technique (HVOF) provides novel possibilities for the manufacturing of cermet coatings with improved mechanical and tribological characteristics. In this study the tribological behavior of HVOF sprayed coatings derived from conventional, fine and nanostructured WC-12Co powders under sliding and rolling wear are investigated and the results are compared to C45 steel (Mat.-No. 1.0503). In addition, sliding and rolling wear effects on a microscopic level are scrutinized. It has been shown that under optimized spray conditions the corresponding fine and nanostructured WC-12Co coatings are able to obtain higher wear resistances and lower friction coefficients than the conventional coatings. This can be attributed to several scaling effects of the microstructure and to the phase evolution of the coating, which are discussed.

  18. Improvement on mechanical properties and wear resistance of HVOF sprayed WC-12Co coatings by optimizing feedstock structure

    NASA Astrophysics Data System (ADS)

    Ma, Ning; Guo, Lei; Cheng, Zhenxiong; Wu, Huantao; Ye, Fuxing; Zhang, Keke

    2014-11-01

    WC-12Co powders with a bimodal size distributed WC particles were used to produce coating by high velocity oxy-fuel (HVOF) spraying (B coating), and HVOF sprayed WC-12Co coatings from microstructured, submicrostructured and nanostructured powders were also fabricated for comparison. The phase constitution, microstructure, mechanical properties and wear performance of the coatings were investigated. Decarburization occurred during coatings preparation, and the carbide retention of B coating was 0.934, higher than that of nanostructured coating. B coating exhibited typical multimodal microstructure, and had considerably high microhardness and the highest fracture toughness among the four coatings, with the values of 1291 HV0.1 and 10.76 MPa m1/2, respectively. When sliding against GCr15 ring in block-on-ring configuration, B coating exhibited the lowest wear rate and relatively lower friction coefficient compared with other coatings, with the average values of 0.94 × 10-7 mm3 N-1 m-1 and 0.63 at 245 N load, respectively, which could be attributed to the concrete-like structure.

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

    NASA Astrophysics Data System (ADS)

    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.

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

    NASA Astrophysics Data System (ADS)

    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.

  1. Micro electrical discharge milling of WC-Co using a deionized water spray and a bipolar pulse

    NASA Astrophysics Data System (ADS)

    Song, Ki Young; Chung, Do Kwan; Park, Min Soo; Chu, Chong Nam

    2010-04-01

    Micro electrical discharge milling (ED-milling) is an effective machining process for manufacturing micro structures on hard metals. This method of machining generally uses kerosene or deionized water as the working fluid, both of which are associated with some problems. Kerosene results in considerable electrode wear and deionized water causes electrolytic corrosion in workpieces. In particular, when cemented tungsten carbide (WC-Co), which has superior strength, hardness and wear resistance, is machined by electrical discharge machining (EDM), the problem of electrolytic corrosion arises as a matter of course since the material is very susceptible to electrolyzation. In this study, spray ED-milling with a bipolar pulsed power source and deionized water was conducted to solve the above problems. This method uses a water spray, which is a mixture of compressed air and deionized water. The spray is injected into the machining gap between the electrode and the workpiece. WC-Co was used for the workpiece and micro grooves were machined on the workpiece. As a result, using the spray ED-milling method, high-quality micro grooves were manufactured on the WC-Co workpiece with no electrolytic corrosion and almost-zero electrode wear.

  2. Evaluation of Cyclic Oxidation and Hot Corrosion Behavior of HVOF-Sprayed WC-Co/NiCrAlY Coating

    NASA Astrophysics Data System (ADS)

    Somasundaram, B.; Kadoli, Ravikiran; Ramesh, M. R.

    2014-08-01

    Corrosion of metallic structural materials at an elevated temperature in complex multicomponent gas environments are potential problems in many fossil energy systems, especially those using coal as a feedstock. Combating these problems involves a number of approaches, one of which is the use of protective coatings. The high velocity oxy fuel (HVOF) process has been used to deposit WC-Co/NiCrAlY composite powder on two types of Fe-based alloys. Thermocyclic oxidation behavior of coated alloys was investigated in the static air as well as in molten salt (Na2SO4-60%V2O5) environment at 700 °C for 50 cycles. The thermogravimetric technique was used to approximate the kinetics of oxidation. WC-Co/NiCrAlY coatings showed a lower oxidation rate in comparison to uncoated alloys. The oxidation resistance of WC-Co/NiCrAlY coatings can be ascribed to the oxide layer of Al2O3 and Cr2O3 formed on the outermost surface. Coated alloys extend a protective oxide scale composed of oxides of Ni and Cr that are known to impart resistance to the hot corrosion in the molten salt environment.

  3. Ultraviolet, visual, and infrared observations of the WC7 variable HD 193793

    NASA Technical Reports Server (NTRS)

    Fitzpatrick, E. L.; Savage, B. D.; Sitko, M. L.

    1982-01-01

    Low-resolution IUE data are used to explore the ultraviolet extinction toward the Wolf-Rayet star HD 193793 and to search for ultraviolet variability that might relate to the infrared variability. High-dispersion IUE observations are used to investigate the nature of the stellar wind of the star and to search for anomalies in the interstellar line spectrum that might be expected to be found toward a star that has recently formed a dust shell. Finally, the ultraviolet and new visual and infrared data are combined to investigate the full energy distribution of this unusual source. The energy distribution is found to extend from 0.12 to 12.5 microns, and the ultraviolet data suggest a normal WC-7 type star. A wind terminal speed of about 3000 km/s is implied by the data, as well as an E(B-V) value of 0.85. The dereddened ultraviolet to visual energy distribution is consistent with a star having effective temperature of about 43,000 K.

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

    NASA Astrophysics Data System (ADS)

    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.

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

    NASA Astrophysics Data System (ADS)

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

    2016-06-01

    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.

  6. The abrasive wear of plasma sprayed nanoscale tungsten carbide-cobalt (WC-Co)

    NASA Astrophysics Data System (ADS)

    Tewksbury, Graham Alfred

    Thermal spray coatings composed of a variety of carbide sizes and cobalt contents were sprayed with a high energy plasma spray system. The size of the carbides used fell into three rough groupings, micrometer scale carbides (1--2 mum), submicrometer (700--300 nm), and nanoscale (≈100 nm). The feedstock powder was evaluated in terms of their size distribution, external morphology, internal morphology, and initial carbide size. Two different fixtures were used in spraying to evaluate the effect of cooling rate on the wear resistance of the coatings. The microstructures of the sprayed coatings were examined using optical metallography, SEM, FESEM, TEM, XRD and chemical analysis. The coatings were evaluated in low stress abrasive wear by the ASTM G-65 Dry Sand Rubber Wheel test. Furthermore, the porosity and hardness of the coatings were evaluated. The cobalt content was found to be the predominant influence on the wear rate of the coatings. The decrease in the carbide size was not found to effect the wear rate of the coatings. Coatings sprayed on the 'hot' fixture were found to have slightly improved wear resistance as compared to coatings sprayed on the 'cold' fixture. The wear rates of the coatings were found to be a function of the WC/Co volume ratio.

  7. Structure Property Relationship of Suspension Thermally Sprayed WC-Co Nanocomposite Coatings

    NASA Astrophysics Data System (ADS)

    Ahmed, R.; Faisal, N. H.; Al-Anazi, Nayef M.; Al-Mutairi, S.; Toma, F.-L.; Berger, L.-M.; Potthoff, A.; Polychroniadis, E. K.; Sall, M.; Chaliampalias, D.; Goosen, M. F. A.

    2015-02-01

    Tribomechanical properties of nanostructured coatings deposited by suspension high velocity oxy-fuel (S-HVOF) and conventional HVOF (Jet Kote) spraying were evaluated. Nanostructured S-HVOF coatings were obtained via ball milling of the agglomerated and sintered WC-12Co feedstock powder, which were deposited via an aqueous-based suspension using modified HVOF (TopGun) process. Microstructural evaluations of these hardmetal coatings included transmission electron microscopy, x-ray diffraction, and scanning electron microscopy equipped with energy dispersive x-ray spectroscopy. The nanohardness and modulus of the coated specimens were investigated using a diamond Berkovich nanoindenter. Sliding wear tests were conducted using a ball-on-flat test rig. Results indicated that low porosity coatings with nanostructured features were obtained. High carbon loss was observed, but coatings showed a high hardness up to 1000 HV2.9N. S-HVOF coatings also showed improved sliding wear and friction behavior, which were attributed to nanosized particles reducing ball wear in three-body abrasion and support of metal matrix due to uniform distribution of nanoparticles in the coating microstructure.

  8. On the shielding effect of a multiligament zone of a crack in WC-Co

    SciTech Connect

    Kotoul, M.

    1997-08-01

    A crack tip shielding analysis of the fracture of cobalt reinforced tungsten carbide hardmetals is developed. It is shown that a multiligament zone formed by ductile binder ligaments behind the crack tip strongly affects the cleavage process in the WC matrix. This is due to a decrease in both the crack tip opening displacement and the plastic zone size ahead of a blunting crack tip. Consequently, normal stresses build up and, as a result, cleavage of the matrix is facilitated even under a low local stress intensity factor perceived by the crack tip. The cooperation of the cleavage of the matrix and the tearing of binder ligaments by dimple rupture results in a meandering crack path with a surprisingly high ligament area fraction. This ligament area fraction is about 15% higher than the volume fraction of the cobalt binder. It is suggested that the facilitated cleavage process promotes an advance of the crack front and maximizes the reduction of the potential energy of a body. The partition between carbide and binder phase related fracture is predicted.

  9. Circumstellar Carbonaceous Material Associated with Late-Type Dusty WC Wolf-Rayet Stars

    NASA Astrophysics Data System (ADS)

    Chiar, J. E.; Tielens, A. G. G. M.

    2001-04-01

    We have studied the 5-8.5 μm infrared spectra of the late-type Wolf-Rayet stars WR 118, WR 112, and WR 104, the WN star WR 147, the B5 hypergiant Cygnus OB2 No. 12, and the Galactic center luminous blue variable Pistol Star using the Short Wavelength Spectrometer on the Infrared Space Observatory. We attribute an absorption feature at 6.2 μm in the spectra of WC stars to amorphous carbon dust. This absorption feature is not detected in the diffuse interstellar medium toward the WR 147, Cyg OB2 No. 12, or the Pistol Star, and therefore we suggest that it is circumstellar in nature. In addition, we detect a broad absorption feature extending from approximately 6.5 to 8 μm. We tentatively attribute this absorption to the CC stretching modes that accompany the 6.2 μm band in aromatic materials. Our analysis of the 6.2 μm absorption profile suggests that the dust grains have to be rather large (~1 μm) and point toward dense clumps as the sites of dust formation. Based on observations made with the Infrared Space Observatory, an ESA project with instruments funded by ESA member states (especially the PI countries: France, Germany, the Netherlands, and the United Kingdom) and with the participation of ISAS and NASA.

  10. Hemodialysis access procedures

    MedlinePlus

    Kidney failure - chronic-dialysis access; Renal failure - chronic-dialysis access; Chronic renal insufficiency-dialysis access; Chronic kidney failure-dialysis access; Chronic renal failure-dialysis access

  11. Performance of an optical equalizer in a 10 G wavelength converting optical access network.

    PubMed

    Mendinueta, José Manuel D; Cao, Bowen; Thomsen, Benn C; Mitchell, John E

    2011-12-12

    A centralized optical processing unit (COPU) that functions both as a wavelength converter (WC) and optical burst equaliser in a 10 Gb/s wavelength-converting optical access network is proposed and experimentally characterized. This COPU is designed to consolidate drifting wavelengths generated with an uncooled laser in the upstream direction into a stable wavelength channel for WDM backhaul transmission and to equalize the optical loud/soft burst power in order to relax the burst-mode receiver dynamic range requirement. The COPU consists of an optical power equaliser composed of two cascaded SOAs followed by a WC. Using an optical packet generator and a DC-coupled PIN-based digital burst-mode receiver, the COPU is characterized in terms of payload-BER for back-to-back and backhaul transmission distances of 22, 40, and 62 km. We show that there is a compromise between the receiver sensitivity and overload points that can be optimized tuning the WC operating point for a particular backhaul fiber transmission distance. Using the optimized settings, sensitivities of -30.94, -30.17, and -27.26 dBm with overloads of -9.3, -5, and >-5 dBm were demonstrated for backhaul transmission distances of 22, 40 and 62 km, respectively. PMID:22274023

  12. The effect of spraying parameters on micro-structural properties of WC-12%Co coating deposited on copper substrate by HVOF process

    NASA Astrophysics Data System (ADS)

    Sathwara, Nishit; Jariwala, C.; Chauhan, N.; Raole, P. M.; Basa, D. K.

    2015-08-01

    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.

  13. Synthesis of micro- or nano-crystalline diamond films on WC-Co substrates with various pretreatments by hot filament chemical vapor deposition

    NASA Astrophysics Data System (ADS)

    Wei, Qiu-ping; Yu, Z. M.; Ashfold, Michael N. R.; Ye, J.; Ma, L.

    2010-04-01

    Diamond films deposited on tungsten carbide can lead to major improvements in the life and performance of cutting tools. However, deposition of diamond onto cemented tungsten carbide (WC-Co) is problematic due to the cobalt binder in the WC. This binder provides additional toughness to the tool but results in poor adhesion and low nucleation density of any diamond film. A two-step chemical etching pretreatment (Murakami reagent and Caro acid, (MC)-pretreatment) and a boronization pretreatment have both been used extensively to improve adhesion of CVD diamond film on WC-Co substrates. Here we discuss the applicability of MC-pretreatment for a range of Co-containing WC-Co substrates, and demonstrate a controlled synthesis process based on liquid boronizing pretreatment for obtaining smooth and dense micro- or nano-crystalline diamond films on high Co-containing WC-Co substrates. Substrate treatments and deposition parameters were found to have major influences on the smoothness, structure and quality of the diamond films. The best quality diamond films were achieved under conditions of relatively high substrate temperature ( Ts) and the best adhesion was achieved at Ts = 800 °C.

  14. The effect of spraying parameters on micro-structural properties of WC-12%Co coating deposited on copper substrate by HVOF process

    SciTech Connect

    Sathwara, Nishit; Jariwala, C. Chauhan, N.; Raole, P. M.; Basa, D. K.

    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.

  15. Work function tuning of plasma-enhanced atomic layer deposited WC{sub x}N{sub y} electrodes for metal/oxide/semiconductor devices

    SciTech Connect

    Zonensain, Oren; Fadida, Sivan; Eizenberg, Moshe; Fisher, Ilanit; Gao, Juwen; Chattopadhyay, Kaushik; Harm, Greg; Mountsier, Tom; Danek, Michal

    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.

  16. FeAl-TiC and FeAl-WC composites - melt infiltration processing, microstructure and mechanical properties

    SciTech Connect

    Subramanian, R.; Schneibel, J.H.

    1997-04-01

    TiC-based and WC-based cermets were processed with iron aluminide, an intermetallic, as a binder by pressureless melt infiltration to near full density (> 97 % theoretical density). Phase equilibria calculations in the quaternary Fe-Al-Ti-C and Fe-Al-W-C systems at 145{degrees}C were performed to determine the solubility of the carbide phases in liquid iron aluminide. This was done by using Thermocalc{trademark} and the results show that molten Fe-40 at.% Al in equilibrium with Ti{sub 0.512}C{sub 0.488} and graphite, dissolves 4.9 at% carbon and 64 atomic ppm titanium. In the Fe-Al-W-C system, liquid Fe-40 at.% Al in equilibrium with graphite dissolves about 5 at.% carbon and 1 at.% tungsten. Due to the low values for the solubility of the carbide phases in liquid iron aluminide, liquid phase sintering of mixed powders does not yield a dense, homogeneous microstructure for carbide volume fractions greater than 0.70. Melt infiltration of molten FeAl into TiC and WC preforms serves as a successful approach to process cermets with carbide contents ranging from 70 to 90 vol. %, to greater than 97% of theoretical density. Also, the microstructures of cermets prepared by melt infiltration were very homogeneous. Typical properties such as hardness, bend strength and fracture toughness are reported. SEM observations of fracture surfaces suggest the improved fracture toughness to result from the ductility of the intermetallic phase. Preliminary experiments for the evaluation of the oxidation resistance of iron aluminide bonded cermets indicate that they are more resistant than WC-Co cermets.

  17. Replication of microchannel structures in WC-Co feedstock using elastomeric replica moulds by hot embossing process.

    PubMed

    Sahli, M; Gelin, J-C; Barrière, T

    2015-10-01

    Hot embossing is a net shaping process that is able to produce the micro-components of polymers with intrinsic and complex shapes at lower cost compared with machining and injection moulding. However, the emboss of hard metals, such as WC-Co, is more challenging due to their high thermal conductivity and ease of agglomeration. Thus, a WC-Co alloy mixed with a wax-based binder feedstock was selected. The formed feedstock exhibited pseudo-plastic flow and was successfully embossed (green part). Here, we developed a novel process that is used to replicate polymer microfluidic chips while simultaneously reducing the channel surface roughness of the mould insert, yielding optical-grade (less than 100 nm surface roughness) channels and reservoirs. This paper concerns the replication of metallic microfluidic mould inserts in WC-Co and the parameters associated with feedstock formation via a hot embossing process. A suitable formulation for micro-powder hot embossing has been established and characterised by thermogravimetric analyses and measurements of mixing torques to verify and quantify the homogeneity of the proposed feedstocks. The relative density of the samples increased with processing temperature, and almost fully dense materials were obtained. In this work, the effects of the sintering temperature on the physical properties were systematically analysed. The evolution of the metal surface morphology during the hot embossing process was also investigated. The results indicate that the feedstock can be used to manufacture micro-fluidic die mould cavities with a low roughness, proper dimensions and good shape retention. The shrinkage of the sintered part was approximately 19-24% compared with that of the brown part. PMID:26117760

  18. Research on the Friction and Wear Behavior at Elevated Temperature of Plasma-Sprayed Nanostructured WC-Co Coatings

    NASA Astrophysics Data System (ADS)

    Chen, Hui; Gou, Guoqing; Tu, Mingjing; Liu, Yan

    2010-02-01

    Nanostructured and ultra-fine WC-Co coatings were prepared by plasma spray. The friction and wear behavior at elevated temperature and failure mechanism were investigated. The results indicated that the sliding wear resistance of nanostructured coating is better than that of ultra-fine coating at high temperature. The wear mechanism is different between ultra-fine coating and nanostructured coating. Brittle fracture and adhesive wear dominate in ultra-fine coating followed with abrasive wear. Toughness fracture and abrasive wear dominate in nanostructured coating followed with adhesive wear.

  19. Optimizing HVOF Spray Parameters to Maximize Bonding Strength of WC-CrC-Ni Coatings on AISI 304L Stainless Steel

    NASA Astrophysics Data System (ADS)

    Thiruvikraman, C.; Balasubramanian, V.; Sridhar, K.

    2014-06-01

    High velocity oxygen fuel (HVOF)-sprayed cermet coatings are extensively used to combat erosion-corrosion in naval applications and in slurry environments. HVOF spray parameters such as oxygen flow rate, fuel flow rate, powder feed rate, carrier gas flow rate, and spray distance have significant influence on coating characteristics like adhesion bond strength and shear strength. This paper presents the use of statistical techniques in particular response surface methodology (RSM), analysis of variance, and regression analysis to develop empirical relationships to predict adhesion bond strength and lap shear bond strength of HVOF-sprayed WC-CrC-Ni coatings. The developed empirical relationships can be effectively used to predict adhesion bond strength and lap shear bond strength of HVOF-sprayed WC-CrC-Ni coatings at 95% confidence level. Response graphs and contour plots were constructed to identify the optimum HVOF spray parameters to attain maximum bond strength in WC-CrC-Ni coatings.

  20. SECM characterization of Pt-Ru-WC and Pt-Ru-Co ternary thin film combinatorial libraries as anode electrocatalysts for PEMFC

    NASA Astrophysics Data System (ADS)

    Lu, Guojin; Cooper, James S.; McGinn, Paul J.

    Rapid screening of electrocatalytic activity of ternary Pt-Ru-WC and Pt-Ru-Co thin film gradient material libraries towards hydrogen oxidation in the presence or absence of CO adsorption was performed by scanning electrochemical microscopy. It was observed that the addition of WC or Co to Pt or Pt-Ru catalysts can improve their hydrogen oxidation reaction activity and CO tolerance, making them suitable as potential electrocatalysts for polymer electrolyte membrane fuel cells. The stability of WC and Co in the acidic electrolyte were enhanced by alloying with Pt. SECM offers the capability for both qualitative and quantitative characterization of electrocatalytic activity of thin films of potential fuel cell electrode material candidates. However, promising electrode compositions identified by this technique need to be verified by traditional electrode preparation and characterization techniques.

  1. An ergonomic evaluation of nursing assistants' job in a nursing home.

    PubMed

    Garg, A; Owen, B D; Carlson, B

    1992-09-01

    Thirty-eight nursing assistants (NAs) in a nursing home ranked and rated 16 different patient handling tasks for perceived stresses to the low back. The nursing assistants were observed for 79 4 h shifts and were videotaped for 14 4 h shifts to describe a typical workday and to determine the number of patient-handling tasks performed per shift, the use of assistive devices, and biomechanical stresses to the low back. In addition, data were collected on nursing assistants' and patients' characteristics. The top eight ranked tasks included transferring patient from toilet to wheelchair (WC), WC to toilet, WC to bed, bed to WC, bathtub to WC, chairlift to WC, weighing patients and lifting patients up in bed. The mean ratings of perceived exertion for these tasks were between 'somewhat hard' and 'hard'. The estimated compressive force on L5/S1 disc for the 50th percentile patient weight ranged from 3.7 to 4.9 KN. Nursing assistants worked in teams of two and performed 24 patient transfers per 8 h shift by manually lifting and carrying patients. Assistive devices (a hydraulic lift and gait belt) were used less than 2% of the time. Patient safety and comfort, lack of accessibility, physical stresses associated with the devices, lack of skill, increased transfer time, and lack of staffing were some of the reasons for not using these assistive devices. Environmental barriers (such as confined workplaces, an uneven floor surface, lack of adjustability of beds, stationary railings around the toilet, etc.) made the job more difficult. Nursing assistants had a high prevalence of low-back pain and 51% of nursing assistants visited a health care provider in the last three years for work related low-back pain. PMID:1387079

  2. Orbitally modulated dust formation by the WC7+O5 colliding-wind binary WR140

    NASA Astrophysics Data System (ADS)

    Williams, P. M.; Marchenko, S. V.; Marston, A. P.; Moffat, A. F. J.; Varricatt, W. P.; Dougherty, S. M.; Kidger, M. R.; Morbidelli, L.; Tapia, M.

    2009-05-01

    We present high-resolution infrared (2-18 μm) images of the archetypal periodic dust-making Wolf-Rayet binary system WR140 (HD 193793) taken between 2001 and 2005, and multi-colour (J - [19.5]) photometry observed between 1989 and 2001. The images resolve the dust cloud formed by WR140 in 2001, allowing us to track its expansion and cooling, while the photometry allows tracking the average temperature and total mass of the dust. The combination of the two data sets constrains the optical properties of the dust, and suggests that they differ from those of the dust made by the WC9 dust-makers, including the classical `pinwheel', WR104. The photometry of individual dust emission features shows them to be significantly redder in (nbL'-[3.99]), but bluer in ([7.9]-[12.5]), than the binary, as expected from the spectra of heated dust and the stellar wind of a Wolf-Rayet star. The most persistent dust features, two concentrations at the ends of a `bar' of emission to the south of the star, were observed to move with constant proper motions of 324 +/- 8 and 243 +/- 7 mas yr-1. Longer wavelength (4.68 and 12.5 μm) images show dust emission from the corresponding features from the previous (1993) periastron passage and dust formation episode, showing that the dust expanded freely in a low-density void for over a decade, with dust features repeating from one cycle to the next. A third persistent dust concentration to the east of the binary (the `arm') was found to have a proper motion ~320 mas yr-1, and a dust mass about one-quarter that of the `bar'. Extrapolation of the motions of the concentrations back to the binary suggests that the eastern `arm' began expansion four to five months earlier than those in the southern `bar', consistent with the projected rotation of the binary axis and wind-collision region (WCR) on the sky. A comparison of model dust images and the observations constrains the intervals when the WCR was producing sufficiently compressed wind for dust

  3. Microstructure and wear resistance of Fe-based WC coating by multi-track overlapping laser induction hybrid rapid cladding

    NASA Astrophysics Data System (ADS)

    Zhou, Shengfeng; Dai, Xiaoqin; Zheng, Haizhong

    2012-02-01

    The carck-free Fe-based +20 wt% WC coating with large area was produced by mutli-track overlapping laser induction hybrid rapid cladding. The results showed that the maximum laser scanning speed and the maximum feeding rate of powder can be increased to 3500 mm/min and 120 g/min, respectively. The cast WC particles were dissolved almost completely and had a worse wettability with Fe-based metal matrix. The precipitated carbides such as M 12C and M 23C 6 (M=Fe, W, Cr) formed an intergranular network around the primary Fe-based phase enriched with tungsten. The microhardness of coating decreased first, and then increased slightly with an increase in the track. The first track had the highest microhardness (i.e. 870HV 0.2). Moreover, the wear weight of coating approximately had a linear relationship with the sliding distance, and increased with an increase in the sliding speed. The wear rate approximately remained constant with an increase in the sliding distance and was two times lower than that of the hardened steel AISI 1045 with a hardness of 60HRC. The wear mechanism during the dry sliding wear was a combination of oxidation wear and abrasion wear.

  4. Microstructure and Properties of DCP-Derived W-ZrC Composite Using Nontoxic Sodium Alginate to Fabricate WC Preform

    NASA Astrophysics Data System (ADS)

    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.

  5. Friction and wear properties of Ti6Al4V/WC-Co in cold atmospheric plasma jet

    NASA Astrophysics Data System (ADS)

    Xu, Wenji; Liu, Xin; Song, Jinlong; Wu, Libo; Sun, Jing

    2012-10-01

    The friction and wear properties of Ti6Al4V/WC-Co friction pair were studied using an autonomous atmospheric pressure bare electrode cold plasma jet generating device and block-on-ring friction/wear tester, respectively. The study was conducted under air, air jet, nitrogen jet, air cold plasma jet, and nitrogen cold plasma jet atmospheres. Both nitrogen cold and air cold plasma jets effectively reduced the friction coefficients of the friction pairs and decreased friction temperature. The friction coefficient in the nitrogen cold plasma jet decreased to almost 60% compared with that in the air. The scanning electron microscope, energy-dispersive X-ray spectroscope, and X-ray diffraction analyses illustrated that adhesive wear was relieved and the friction surfaces of Ti6Al4V were smoother, both in the nitrogen cold and air cold plasma jets. The roughness value Ra of the Ti6Al4V friction surfaces can reach 1.107 μm. A large number of nitrogen particles in the ionic and excited states contained by cold plasma jets reacts easily on the friction surface to produce a large amount of nitrides, which can excellently reduce the wear of Ti6Al4V/WC-Co friction pairs in real-time.

  6. Influence of Plasma Intensity on Wear and Erosion Resistance of Conventional and Nanometric WC-Co Coatings Deposited by APS

    NASA Astrophysics Data System (ADS)

    Bonache, V.; Salvador, M. D.; García, J. C.; Sánchez, E.; Bannier, E.

    2011-03-01

    The effects of plasma intensity and powder particle size on wear and erosion resistance have been evaluated for WC-12 wt.%Co coatings deposited by Air Plasma Spraying. Coatings were deposited from micrometric and nanostructured powders. SEM and XRD characterization showed the presence of WC, W2C, W, and an amorphous Co-rich matrix. The performance of the different coatings was compared in sliding wear tests (ball-on-disk), under dry friction conditions. Wear debris and tracks were analyzed by SEM. The debris generated during the test was found to have a great influence on the sliding properties. Wear follows a "three-body abrasive mechanism" and is dominated by coating spallation because of sub-surface cracking. In order to evaluate erosion behavior, solid particle erosion tests were conducted. Eroded coatings were analyzed by SEM, and erosion mainly occurs by a "cracking and chipping mechanism." The study shows that wear and erosion behavior is strongly affected by plasma arc intensity.

  7. Mechanical and Electro-Chemical Properties of Laser Surface Alloyed AISI 304 Stainless Steel with WC+Ni+NiCr

    NASA Astrophysics Data System (ADS)

    Majumdar, J. D.

    In the present study, a detailed evaluation of wear and corrosion resistance properties of laser surface alloyed of AISI 304 stainless steel with WC+Ni+NiCr (in the ratio of 70:15:15) has been undertaken. Laser processing has been carried out using a 5 kW continuous wave (CW) Nd:YAG laser (at a beam diameter of 3 mm) by surface melting and simultaneous deposition of precursor powder mixture in the melt zone (at a flow rate of 10 mg/s) and using Ar shroud at a gas flow rate of 5 l/min. Followed by laser processing, a detailed evaluation of fretting wear behavior has been conducted against WC surface. Finally, the corrosion property is measured using a potentiodynamic polarization testing unit in a 3.56 wt.% NaCl solution. The wear resistance property is significantly improved due to laser surface alloying which is attributed to the improvement in surface microhardness to 1350 VHN as compared to 220 VHN of as-received γ-stainless steel substrate. The mechanism of wear is established. The pitting corrosion resistance property is also improved due to the presence of Ni and Cr in solution and homogenization of microstructure due to laser processing.

  8. Laser dispersing of WC and TiC powders in light metal alloys for wear resistance enhancement

    NASA Astrophysics Data System (ADS)

    Jendrzejewski, Rafał; Śliwiński, Gerard

    2015-01-01

    In this work, formation of the Metal Matrix Composite (MMC) surface layers on the titanium-based Ti-6Al-4V and aluminum-based Al 6061 alloys by means of laser dispersing of WC and TiC powder particles is investigated. In the process, the substrate surface is locally melted to the depths up to about several hundreds μm by the slightly defocused high power CO2 or disk Yb:YAG laser beam. Simultaneously, powder particles of irregular (TiC) or spherical (WC) shape and average size of about 100 microns are injected into the molten material by means of specialized, lateral nozzle. The single traces as well as surface layers consisting of several consecutive traces were produced. The influence of the process parameters, such as: laser beam intensity, scanning speed, powder feed-rate and substrate preheating temperature, on the properties of the composite layer was analyzed and discussed. The optical and SEM inspections of the produced MMC materials revealed the homogeneously distributed powder particles in the best samples obtained.

  9. Learning to Question: The Roles of Multiple Hypotheses, Successive Approximations, Balloons and Toilet Paper in University Science Programs of Southwestern Amazonia

    NASA Astrophysics Data System (ADS)

    Brown, I. Foster

    2008-06-01

    Learning to question is essential for determining pathways of conservation and development in southwestern Amazonia during a time of rapid global environmental change. Teaching such an approach in graduate science programs in regional universities can be done using play-acting and simulation exercises. Multiple working hypotheses help students learn to question their own research results and expert witnesses. The method of successive approximations enables students to question the results of complex calculations, such as estimates of forest biomass. Balloons and rolls of toilet paper provide means of questioning two-dimensional representations of a three-dimensional Earth and the value of pi. Generation of systematic errors can illustrate the pitfalls of blind acceptance of data. While learning to question is essential, it is insufficient by itself; students must also learn how to be solutionologists in order to satisfy societal demands for solutions to environmental problems. A little irreverence can be an excellent didactic tool for helping students develop the skills necessary to lead conservation and development efforts in the region.

  10. Meta-genomic analysis of toilet waste from long distance flights; a step towards global surveillance of infectious diseases and antimicrobial resistance

    PubMed Central

    Nordahl Petersen, Thomas; Rasmussen, Simon; Hasman, Henrik; Carøe, Christian; Bælum, Jacob; Charlotte Schultz, Anna; Bergmark, Lasse; Svendsen, Christina A.; Lund, Ole; Sicheritz-Pontén, Thomas; Aarestrup, Frank M.

    2015-01-01

    Human populations worldwide are increasingly confronted with infectious diseases and antimicrobial resistance spreading faster and appearing more frequently. Knowledge regarding their occurrence and worldwide transmission is important to control outbreaks and prevent epidemics. Here, we performed shotgun sequencing of toilet waste from 18 international airplanes arriving in Copenhagen, Denmark, from nine cities in three world regions. An average of 18.6 Gb (14.8 to 25.7 Gb) of raw Illumina paired end sequence data was generated, cleaned, trimmed and mapped against reference sequence databases for bacteria and antimicrobial resistance genes. An average of 106,839 (0.06%) reads were assigned to resistance genes with genes encoding resistance to tetracycline, macrolide and beta-lactam resistance genes as the most abundant in all samples. We found significantly higher abundance and diversity of genes encoding antimicrobial resistance, including critical important resistance (e.g. blaCTX-M) carried on airplanes from South Asia compared to North America. Presence of Salmonella enterica and norovirus were also detected in higher amounts from South Asia, whereas Clostridium difficile was most abundant in samples from North America. Our study provides a first step towards a potential novel strategy for global surveillance enabling simultaneous detection of multiple human health threatening genetic elements, infectious agents and resistance genes. PMID:26161690

  11. Floors and Toilets: Association of Floors and Sanitation Practices with Fecal Contamination in Peruvian Amazon Peri-Urban Households.

    PubMed

    Exum, Natalie G; Olórtegui, Maribel Paredes; Yori, Pablo Peñataro; Davis, Meghan F; Heaney, Christopher D; Kosek, Margaret; Schwab, Kellogg J

    2016-07-19

    Over two billion people worldwide lack access to an improved sanitation facility that adequately retains or treats feces. This results in the potential for fecal material containing enteric pathogens to contaminate the environment, including household floors. This study aimed to assess how floor type and sanitation practices impacted the concentration of fecal contamination on household floors. We sampled 189 floor surfaces within 63 households in a peri-urban community in Iquitos, Peru. All samples were analyzed for colony forming units (CFUs) of E. coli, and households were evaluated for their water, sanitation, and hygiene characteristics. Results of multivariate linear regression indicated that households with improved sanitation and cement floors in the kitchen area had reduced fecal contamination to those with unimproved sanitation and dirt floors (Beta: -1.18 log10 E. coli CFU/900 cm(2); 95% confidence interval [CI]: -1.77, -0.60). Households that did not versus did share their sanitation facility also had less contaminated kitchen floors (Beta: -0.65 log10 E. coli CFU/900 cm(2); 95% CI: -1.15, -0.16). These findings suggest that the sanitation facilities of a home may impact the microbial load found on floors, contributing to the potential for household floors to serve as an indirect route of fecal pathogen transmission to children. PMID:27338564

  12. Synergistic effect of ultrasonic cavitation erosion and corrosion of WC-CoCr and FeCrSiBMn coatings prepared by HVOF spraying.

    PubMed

    Hong, Sheng; Wu, Yuping; Zhang, Jianfeng; Zheng, Yugui; Zheng, Yuan; Lin, Jinran

    2016-07-01

    The high-velocity oxygen-fuel (HVOF) spraying process was used to fabricate conventional WC-10Co-4Cr coatings and FeCrSiBMn amorphous/nanocrystalline coatings. The synergistic effect of cavitation erosion and corrosion of both coatings was investigated. The results showed that the WC-10Co-4Cr coating had better cavitation erosion-corrosion resistance than the FeCrSiBMn coating in 3.5 wt.% NaCl solution. After eroded for 30 h, the volume loss rate of the WC-10Co-4Cr coating was about 2/5 that of the FeCrSiBMn coating. In the total cumulative volume loss rate under cavitation erosion-corrosion condition, the pure cavitation erosion played a key role for both coatings, and the total contribution of pure corrosion and erosion-induced corrosion of the WC-10Co-4Cr coating was larger than that of the FeCrSiBMn coating. Mechanical effect was the main factor for cavitation erosion-corrosion behavior of both coatings. PMID:26964984

  13. Comparison of the Mechanical and Electrochemical Properties of WC-25Co Coatings Obtained by High Velocity Oxy-Fuel and Cold Gas Spraying

    NASA Astrophysics Data System (ADS)

    Couto, M.; Dosta, S.; Fernández, J.; Guilemany, J. M.

    2014-12-01

    Cold gas spray (CGS) coatings were previously produced by spraying WC-25Co cermet powders onto Al7075-T6 and low-carbon steel substrates. Unlike conventional flame spray techniques (e.g., high-velocity oxy-fuel; HVOF), no melting of the powder occurs; the particles are deformed and bond together after being sprayed by a supersonic jet of compressed gas, thereby building up several layers and forming a coating. WC-Co cermets are used in wear-resistant parts, because of their combination of mechanical, physical, and chemical properties. XRD tests were previously run on the initial powder and the coatings to determine possible phase changes during spraying. The bonding strength of the coatings was measured by adhesion tests. Here, WC-25Co coatings were also deposited on the same substrates by HVOF spraying. The wear resistance and fracture toughness of the coatings obtained previously by CGS and the HVOF coatings obtained here were studied. Their corrosion resistance was determined by electrochemical measurements. It was possible to achieve thick, dense, and hard CGS coatings on Al7075-T6 and low-carbon steel substrates, with better or the same mechanical and electrochemical properties as those of the HVOF coatings; making the former a highly competitive method for producing WC-25Co coatings.

  14. Evolution of the CD163 Family and its Relationship to the Bovine Gamma Delta T Cell Co-receptor WC1

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The scavenger receptor cysteine rich (SRCR) domain is an ancient and highly conserved protein domain. CD163 and WC1 molecules are classed together as group B SRCR superfamily members, along with Spa, CD5 and CD6, all of which are expressed by immune system cells. There are three known types of CD16...

  15. The Different Effects of BMI and WC on Organ Damage in Patients from a Cardiac Rehabilitation Program after Acute Coronary Syndrome

    PubMed Central

    Xu, Lin; Zhao, Hui; Qiu, Jian; Zhu, Wei; Lei, Hongqiang; Cai, Zekun; Lin, Wan-Hua; Huang, Wenhua; Zhang, Heye; Zhang, Yuan-Ting

    2015-01-01

    One of the purposes of cardiac rehabilitation (CR) after acute coronary syndrome (ACS) is to monitor and control weight of the patient. Our study is to compare the different obesity indexes, body mass index (BMI), and waist circumference (WC), through one well-designed CR program (CRP) with ACS in Guangzhou city of Guangdong Province, China, in order to identify different effects of BMI and WC on organ damage. In our work, sixty-one patients between October 2013 and January 2014 fulfilled our study. We collected the vital signs by medical records, the clinical variables of body-metabolic status by fasting blood test, and the organ damage variables by submaximal exercise treadmill test (ETT) and ultrasonic cardiogram (UCG) both on our inpatient and four-to-five weeks of outpatient part of CRP after ACS. We mainly used two-tailed Pearson's test and liner regression to evaluate the relationship of BMI/WC and organ damage. Our results confirmed that WC could be more accurate than BMI to evaluate the cardiac function through the changes of left ventricular structure on the CRP after ACS cases. It makes sense of early diagnosis, valid evaluation, and proper adjustment to ACS in CRP of the obesity individuals in the future. PMID:26247035

  16. Effect of SiC Nanowhisker on the Microstructure and Mechanical Properties of WC-Ni Cemented Carbide Prepared by Spark Plasma Sintering

    PubMed Central

    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. PMID:25003143

  17. Southern Vermont College (SVC) and Wheelock College (WC): 2010 Urban and Rural Healthcare Academy Program (HAP) for College Progress and Workforce Development

    ERIC Educational Resources Information Center

    DeCiccio, Albert C.

    2010-01-01

    (Purpose) This is a report about the Urban and Rural Healthcare Academy Pilot Program (HAP) that launched at Southern Vermont College (SVC) and Wheelock College (WC) in summer 2010. HAP enabled 18 vulnerable high school students to learn about how to progress to college, how to transition when they arrive on a college campus, and how to prepare…

  18. Effect of Polishing on the Friction Behaviors and Cutting Performance of Boron-Doped Diamond Films on WC-Co Inserts

    NASA Astrophysics Data System (ADS)

    Wang, Liang; Shen, Bin; Sun, Fanghong; Zhang, Zhiming

    2014-04-01

    Boron doped (B-doped) diamond films are deposited onto WC-Co inserts by HFCVD with the mixture of acetone, trimethyl borate (C3H9BO3) and H2. The as-deposited B-doped diamond films are characterized with scanning electron microscope (SEM), X-ray diffraction (XRD) spectroscopy, Raman spectroscopy, 3D surface topography based on white-light interferometry and Rockwell hardness tester. The effects of mechanical polishing on the friction behavior and cutting performance of B-doped diamond are evaluated by ball-on-plate type reciprocating tribometer and turning of aluminum alloy 7075 materials, respectively. For comparison, the same tests are also conducted for the bare WC-Co inserts with smooth surface. Friction tests suggest that the unpolished and polished B-doped diamond films possess relatively low fluctuation of friction coefficient than as-received bare WC-Co samples. The average stable friction coefficient for B-doped diamond films decreases apparently after mechanical polishing. The values for WC-Co sample, unpolished and polished B-doped diamond films are approximately 0.38, 0.25 and 0.11, respectively. The cutting results demonstrate that the low friction coefficient and high adhesive strength of B-doped diamond films play an essential role in the cutting performance enhancement of the WC-Co inserts. However, the mechanical polishing process may lower the adhesive strength of B-doped diamond films. Consequently, the polished B-doped diamond coated inserts show premature wear in the machining of adhesive aluminum alloy materials.

  19. United States Access Board

    MedlinePlus

    ... disabilities through leadership in accessible design and the development of accessibility guidelines and standards for the built environment, transportation, communication, medical diagnostic equipment, and information technology. ...

  20. Adhesion of tungsten carbide reinforced amorphous hydrocarbon thin films (WC/a-C:H) to steel substrates for tribological applications

    SciTech Connect

    Evans, Ryan D.; Schiller, P. J; Howe, Jane Y

    2011-01-01

    We have explored the adhesive interlayer structure for a tungsten carbide reinforced amorphous hydrocarbon thin film coating (WC/a-C:H) that demonstrated excellent coating adhesion under highly stressed tribological contact. Transmission electron microscopy (TEM) analysis including cross-sectional imaging, electron diffraction, and energy dispersive spectroscopy was performed on abrupt and gradient interfaces within the multilayer film architecture. Interpretation of these results is aided by quantum mechanical calculations that were performed to investigate bonding interactions of the Cr adhesive interlayer to the Fe substrate surface within a - 3 nm thick interfacial region. Low levels of oxygen present in the coating deposition chamber during deposition were found at the Fe-Cr interface using high-resolution TEM. Molecular orbital calculations for a linear three-atom molecular model Fe-O-Cr demonstrate the role of O in strengthening Fe to Cr bonding within that interfacial region.

  1. Adhesion of tungsten carbide reinforced amorphous hydrocarbon thin films (WC/a-C:H) to steel substrates for tribological applications

    NASA Astrophysics Data System (ADS)

    Evans, R. D.; Shiller, P. J.; Howe, J. Y.

    2011-01-01

    We have explored the adhesive interlayer structure for a tungsten carbide reinforced amorphous hydrocarbon thin film coating (WC/a-C:H) that demonstrated excellent coating adhesion under highly stressed tribological contact. Transmission electron microscopy (TEM) analysis including cross-sectional imaging, electron diffraction, and energy dispersive spectroscopy was performed on abrupt and gradient interfaces within the multilayer film architecture. Interpretation of these results is aided by quantum mechanical calculations that were performed to investigate bonding interactions of the Cr adhesive interlayer to the Fe substrate surface within a ˜3 nm thick interfacial region. Low levels of oxygen present in the coating deposition chamber during deposition were found at the Fe-Cr interface using high-resolution TEM. Molecular orbital calculations for a linear three-atom molecular model Fe-O-Cr demonstrate the role of O in strengthening Fe to Cr bonding within that interfacial region.

  2. Toilets and the Smart Grid: A role for history and art in communicating assessed science for Earth—The Operators' Manual

    NASA Astrophysics Data System (ADS)

    Alley, R. B.; Haines-Stiles, G.; Akuginow, E.

    2010-12-01

    Assessed science consistently shows that an economically efficient response to global warming would begin now, with the likelihood of side benefits including increased employment, security, and environmental quality. This result has been obtained consistently for many years, yet societal responses over this time have fallen well short of the economically efficient path, suggesting that society is being strongly influenced by additional considerations. First-hand experience indicates that many people, including many policy-makers, “know” global-warming “science” that did not come from the scientific assessment bodies or their participating scientists. Instead, this supposedly supporting science was provided by opponents of actions to deal with global warming, and was designed to be inaccurate and easily defeated (e.g., “All of global warming theory rests on the correlation between CO2 and temperature”, or “…rests on the hockey stick.”) A useful discussion of possible wise responses to the problem is difficult when so much that many people “know” just isn’t so. The inaccurate information has been presented very effectively, but we believe that accurate information can be presented even more effectively, honestly showing the costs and benefits of efficient response while explicitly addressing the widespread misconceptions. The history of previous environmental issues offers one path forward, with denial preceding solutions in such diverse cases as the San Francisco earthquake and toilets in Edinburgh. We will provide first-hand reports from preparation of an NSF Informal Science Education-funded project, Earth—The Operators’ Manual.

  3. A Theory of Access

    ERIC Educational Resources Information Center

    Ribot, Jesse C.; Peluso, Nancy Lee

    2003-01-01

    The term "access" is frequently used by property and natural resource analysts without adequate definition. In this paper we develop a concept of access and examine a broad set of factors that differentiate access from property. We define access as "the "ability" to derive benefits from things," broadening from property's classical definition as…

  4. World Wide Access: Accessible Web Design.

    ERIC Educational Resources Information Center

    Washington Univ., Seattle.

    This brief paper considers the application of "universal design" principles to Web page design in order to increase accessibility for people with disabilities. Suggestions are based on the World Wide Web Consortium's accessibility initiative, which has proposed guidelines for all Web authors and federal government standards. Seven guidelines for…

  5. Improved method for the preparation of TiN-coated WC-Co-based samples for cross-sectional AEM investigation.

    PubMed

    Hefter, J; Ostreicher, K; Sung, C

    1992-11-01

    An improved method for the preparation of cross-sectional thin foils of coated WC-Co samples for studies by analytical electron microscopy is described. A braze alloy is used to join the sections of the sample together and the resulting sample is stable during subsequent grinding, dimpling, and milling operations. Cross-sectional micrographs provide examples of the efficacy of this method. No microstructural alteration associated with the brazing operation was observed. PMID:1472751

  6. Hemodialysis access procedures

    MedlinePlus

    National Kidney and Urologic Diseases Information Clearinghouse. Vascular Access for Hemodialysis . Updated July 23, 2014. Available at: kidney.niddk.nih.gov/kudiseases/pubs/vascularaccess/index.aspx. Accessed: February 9, 2015. ...

  7. Laser treatment of dual matrix cast iron with presence of WC particles at the surface: Influence of self-annealing on stress fields

    NASA Astrophysics Data System (ADS)

    Yilbas, B. S.; Akhtar, S. S.; Karatas, C.; Boran, K.

    2016-01-01

    Laser control melting of dual matrix cast iron surface is carried out. A carbon film containing 15% WC particles is formed at the surface prior to the laser treatment and the spiral tracks are adopted for laser scanning at the workpiece surface. Morphological, metallurgical, microhardness, and scratch resistance of the laser treated surface are examined using analytical tools. Temperature and stress fields in the laser irradiated region are predicted incorporating ABAQUS finite element code. Predictions of temperature and residual stress at the laser treated surface are validated with the thermocouple and the X-ray diffraction data. It is found that surface temperature and residual stress predictions agree well with their counterparts corresponding to thermocouple data and findings of X-ray diffraction technique. Laser treated surface is free from asperities including voids and micro-cracks despite the mismatch of thermal expansion coefficients of WC and dual matrix cast iron. This behavior is attributed to the self-annealing effects of recently formed spiral tracks on the previously formed tracks during the laser treatment process; in which case, the self-annealing effect modifies the cooling rates and lowers thermal stress levels in the laser treated layer. Laser treated layer consists of a dense region composing of fine grains and WC particles, dendritic and featherlike structures below the dense layer, and the heat affected zone.

  8. Cosintering of Powder Injection Molding Parts Made from Ultrafine WC-Co and 316L Stainless Steel Powders for Fabrication of Novel Composite Structures

    NASA Astrophysics Data System (ADS)

    Simchi, A.; Petzoldt, F.

    2010-01-01

    Sintering response and phase formation during sintering of WC-Co/316L stainless steel composites produced by assembling of powder injection molding (PIM) parts were studied. It is shown that during cosintering a significant mismatch strain (>4 pct) is developed in the temperature range of 1080 °C to 1350 °C. This mismatch strain induces biaxial stresses at the interface, leading to interface delamination. Experimental results revealed that sintering at a heating rate of 20 K/min could be used to decrease the mismatch strain to <2 pct. Meanwhile, WC is decomposed at the contact area and the diffusion of C and Co into the iron lattice results in the formation of a liquid and MC and M6C carbides at 1220 °C. Spreading of the liquid accelerates the reaction, affecting the dimensional stability of the PIM parts. To prevent the reaction, surface oxidation of the cemented carbide followed by hydrogen reduction during sintering was examined. Although the amount of mismatch strain increased, formation of a metallic interface consisting of a W-Co alloy (45 to 50 at. pct Co) and a Co-rich iron alloy (18 at. pct Co) prevented the decomposition of WC and melt formation. It is also shown that the deposition of a thin Ni layer after thermal debinding decreases the mismatch stresses through melt formation, although interlayer diffusion causes pore-band formation close to the steel part.

  9. Synthesis of diamond on WC-Co substrates using a KrF excimer laser in combination with a combustion flame

    NASA Astrophysics Data System (ADS)

    Han, Y. X.; Ling, H.; Lu, Y. F.

    2007-02-01

    A KrF excimer laser was used in combination with a combustion flame to deposit diamond films on cemented tungsten carbide (WC-Co) substrates. The laser has a wavelength of 248 nm, a pulse width of 23 ns, a pulse energy range of 84~450 mJ, and a repetition rate up to 50 Hz. Using the combustion flame method, diamond films were deposited on the laser-processed WC-Co substrates for 10 min. The morphologies of the deposited diamond films were examined using a scanning electron microscopy (SEM). The composition and bonding structures in the deposited films were studied by energy dispersive X-ray analysis (EDX) and Raman spectroscopy, respectively. The film adhesion was characterized by scratching a razor across the films. It was found that C composition on WC-Co substrate surfaces was eliminated by the laser irradiation. As a consequence, diamond nucleation density decreased and diamond grains grew larger in the laser-processed areas. Based on the experimental results, a film growth mechanism at different deposition temperature ranges corresponding to pre-deposition laser-surface-treatment effects was proposed.

  10. The effects of pulse electrodeposition parameters on morphology, hardness and wear behavior of nano-structure Cr-WC composite coatings

    NASA Astrophysics Data System (ADS)

    Rezaei-Sameti, M.; Nadali, S.; Rajabi, J.; Rakhshi, M.

    2012-08-01

    Electrodeposition of nano-structured Cr-WC had been carried out from a trivalent chromium bath using a square shaped pulse current. The average size of WC particles was 70 nm. The effect of pulse electroplating parameters such as current density and duty cycle on the amount of incorporated WC particles and morphology of the coatings was investigated. The structure and morphology of the coatings were studied by X-ray diffraction (XRD) and scanning electron microscopy (SEM) techniques. In addition, the hardness and tribological behavior of the coatings were investigated by micro hardness and pin on disk methods, respectively. The results showed that with decreasing duty cycle, the volume percentage, hardness and wear resistance of coating increased. Also, by increasing the current density up to 15 A/dm2, the both of volume percentage and hardness will increase. An increase in current density up to 20 A/dm2, had an inverse results. Finally the optimum wear resistance was achieved at the current density of 8 A/dm2, duty cycle of 50%.

  11. Microstructures and mechanical properties of metallic NiCrBSi and composite NiCrBSi-WC layers manufactured via hybrid plasma/laser process

    NASA Astrophysics Data System (ADS)

    Serres, Nicolas; Hlawka, Françoise; Costil, Sophie; Langlade, Cécile; Machi, Frédérique

    2011-04-01

    Thermal spraying is already used in industry to protect mechanical parts against wear and/or corrosion, but results are not always satisfactory due to porosity and microstructures. In this study, atmospheric plasma spraying (APS) and in situ laser irradiation by diode laser processes were combined to modify structural characteristics of metallic NiCrBSi and composite NiCrBSi-WC coatings. The microstructure evolution was studied with the chemical composition analysis by XRD and SEM coupled with EDS techniques. Instrumented nanoindentation tests were also conducted employing a Berkovich indenter. Moreover, the effect of the influence of the volume fraction of the reinforcing WC particles on the formation and mechanical performances of the layer was also investigated. Results show that in situ laser remelting induces the growth of a dendritic structure which strongly decreases the porosity of as-sprayed coatings, without solidification cracking (one of the major defects that can occur during the solidification of metallic or composite alloys) and improves the mechanical properties of the layer. Indeed, the layer properties such as hardness, elastic modulus, shear strength and wear rate are dependent on the percentage of WC particles in the mixture.

  12. Assessment of Abrasive Wear of Nanostructured WC-Co and Fe-Based Coatings Applied by HP-HVOF, Flame, and Wire Arc Spray

    NASA Astrophysics Data System (ADS)

    Lima, C. R. C.; Libardi, R.; Camargo, F.; Fals, H. C.; Ferraresi, V. A.

    2014-10-01

    Thermal spray processes have been widely used to minimize losses caused by wear mechanisms. Sprayed deposits using conventional wire and powder materials have been long solving tribological problems in engineering equipment. More recently, the option for new different technologies and consumables like nanostructured powder materials and nanocomposite cored wires have expanded the possibilities for technical solutions. Cored wire technology allows the use of compositions that cannot be drawn into wire form like carbides in metallic matrix and high-temperature materials, thus, intensifying the use of spraying processes with low operating cost to demanding wear and corrosion applications. The objective of this work was to study the mechanical characteristics and wear performance of coatings obtained by Flame, Wire Arc, and HVOF spraying using selected nanostructured WC10Co4Cr, WC12Co, and Fe-based 140 MXC powder and wire materials. Abrasive wear performance of the coatings was determinate following the ASTM G-65 standard. Based on the results, a higher abrasive wear resistance was found for the HVOF-sprayed WC10Co4Cr nanostructured coating.

  13. [Accessible Rural Housing.

    ERIC Educational Resources Information Center

    Baker, Nick, Ed.

    1995-01-01

    This issue of the quarterly newsletter "Rural Exchange" provides information and resources on accessible rural housing for the disabled. "Accessible Manufactured Housing Could Increase Rural Home Supply" (Nick Baker) suggests that incorporation of access features such as lever door handles and no-step entries into manufactured housing could help…

  14. Open Access Alternatives

    ERIC Educational Resources Information Center

    Tenopir, Carol

    2004-01-01

    Open access publishing is a hot topic today. But open access publishing can have many different definitions, and pros and cons vary with the definitions. Open access publishing is especially attractive to companies and small colleges or universities that are likely to have many more readers than authors. A downside is that a membership fee sounds…

  15. Demystifying Remote Access

    ERIC Educational Resources Information Center

    Howe, Grant

    2009-01-01

    With money tight, more and more districts are considering remote access as a way to reduce expenses and budget information technology costs more effectively. Remote access allows staff members to work with a hosted software application from any school campus without being tied to a specific physical location. Each school can access critical…

  16. Open Access and beyond.

    PubMed

    Mathur, Shawn; Schmidt, Christian; Das, Chhaya; Tucker, Philip W

    2006-01-01

    Uncensored exchange of scientific results hastens progress. Open Access does not stop at the removal of price and permission barriers; still, censorship and reading disabilities, to name a few, hamper access to information. Here, we invite the scientific community and the public to discuss new methods to distribute, store and manage literature in order to achieve unfettered access to literature. PMID:16956402

  17. Reflective Database Access Control

    ERIC Educational Resources Information Center

    Olson, Lars E.

    2009-01-01

    "Reflective Database Access Control" (RDBAC) is a model in which a database privilege is expressed as a database query itself, rather than as a static privilege contained in an access control list. RDBAC aids the management of database access controls by improving the expressiveness of policies. However, such policies introduce new interactions…

  18. Formation Mechanisms, Structure, and Properties of HVOF-Sprayed WC-CoCr Coatings: An Approach Toward Process Maps

    NASA Astrophysics Data System (ADS)

    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.

  19. Microstructural characterization of WC-TiC-Co cutting tools during high-speed machining of P20 mold steel

    SciTech Connect

    Farhat, Z.N

    2003-10-15

    The wear behavior of tungsten carbide (WC)-TiC-Co cutting tools during cutting P20 tool steel was investigated. Orthogonal cutting tests were performed on a CNC lathe using five speeds, namely, 60, 120, 240, 380 and 600 m/min. Wear, as the width of the wear land, was monitored at five time intervals. Wear characterization of the rake and the flank surfaces as well as the collected chips was performed using scanning electron microscopy (SEM), backscattered electron imaging and energy-dispersive X-ray analysis (EDX). Microhardness of collected chips was also performed to monitor strain hardening effects during cutting. Two dominant wear mechanisms were identified: at high speed (380-600 m/min), wear was found to occur by a melt wear mechanism; at low speed (60-120 m/min), adhesion (built-up edge) followed by delamination was found to be the cause of wear damage. It was also found that deformation in the chips occurred by localized shear deformation.

  20. WC-Co and Cr3C2-NiCr Coatings in Low- and High-Stress Abrasive Conditions

    NASA Astrophysics Data System (ADS)

    Kašparová, Michaela; Zahálka, František; Houdková, Šárka

    2011-03-01

    The article deals with the evaluation of abrasive wear resistance and adhesive strength of thermally sprayed coatings. The main attention was paid to differences between low- and high-stress abrasive conditions of the measuring. Conclusions include the evaluation of specific properties of the WC-Co and the Cr3C2-NiCr High Velocity Oxygen Fuel coatings and the evaluation of the changes in the behavior of the abrasive media. Mainly, the relationship between the low- and high-stress abrasion conditions and the wear mechanism in the tested materials was described. For the wear test, the abrasive media of Al2O3 and SiO2 sands were chosen. During wear tests, the volume loss of the tested materials and the surface roughness of the wear tracks were measured. The wear tracks on the tested materials and abrasive sands' morphologies were observed using Scanning Electron Microscopy. It was found that high-stress abrasive conditions change the coatings' behavior very significantly, particularly that of the Cr3C2-NiCr coating. Adhesive-cohesive properties of the coatings and relationships among individual structure particles were evaluated using tensile testing. It was found that the weak bond strength among the individual splats, structure particles, and phases plays a role in the poor wear resistance of the coatings.

  1. The Use of Acoustic Emission to Characterize Fracture Behavior During Vickers Indentation of HVOF Thermally Sprayed WC-Co Coatings

    NASA Astrophysics Data System (ADS)

    Faisal, N. H.; Steel, J. A.; Ahmed, R.; Reuben, R. L.

    2009-12-01

    This paper describes how acoustic emission (AE) measurements can be used to supplement the mechanical information available from an indentation test. It examines the extent to which AE data can be used to replace time-consuming surface crack measurement data for the assessment of fracture toughness of brittle materials. AE is known to be sensitive to fracture events and so it was expected that features derived from the AE data may provide information on the processes (microscale and macroscale fracture events and densification) occurring during indentation. AE data were acquired during indentation tests on samples of a WC-12%Co coating of nominal thickness 300 μm at a variety of indentation loads. The raw AE signals were reduced to three stages and three features per stage, giving nine possible indicators per indentation. Each indicator was compared with the crack profile, measured both conventionally and using a profiling method which gives the total surface crack length around the indent. A selection of the indents was also sectioned in order to make some observations on the subsurface damage. It has been found that reproducible AE signals are generated during indentation involving three distinct stages, associated, respectively, with nonradial cracking, commencement of radial cracking, and continued descent of the indenter. It has been shown that AE can give at least as good a measure of cracking processes during indentation as is possible using crack measurement after indentation.

  2. Effect of Silicon Doping in Cvd Diamond Films from Microcrystalline to Nanocrystalline on WC-Co Substrates

    NASA Astrophysics Data System (ADS)

    Zhang, Jianguo; Cui, Yuxiao; Shen, Bin; Sun, Fanghong

    2013-12-01

    Si-doped diamond films with various Si concentrations are deposited on WC-Co substrates using HFCVD method, with the mixture of acetone, tetraethoxysilane (TEOS) and hydrogen as the reactant source. A variety of characterizations, including FE-SEM, AFM, Raman, XRD, surface profilometer and Rockwell indentation, are conducted to systematically investigate the influence of Si incorporation on diamond films. As the Si/C ratio from 0% to 5%, the grain size of as-deposited films decreases from 4 μm to about 50 nm, and the surface roughness reduces from Ra 290 nm to Ra 180 nm. Besides, the intensity ratio of I(111)/I(220) varies from 0.57 to 0, indicating the <110> preferred orientation of the nanocrystalline structure in the 5% doped diamond films. The silicon doping is beneficial for the formation of non-diamond carbide phases in the films, according to the Raman spectra. Moreover, the film adhesion is also improved with the increase of Si/C ratio.

  3. Effect of cobalt content on wear and corrosion behaviors of electrodeposited Ni-Co/WC nano-composite coatings.

    PubMed

    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. PMID:23646637

  4. Laser removal of TiN coatings from WC micro-tools and in-process monitoring

    NASA Astrophysics Data System (ADS)

    Marimuthu, S.; Kamara, A. M.; Whitehead, D.; Mativenga, P.; Li, L.

    2010-11-01

    Current environmental challenges require sustainable and extended use and re-use of materials. For example, the service life of engineering tooling can be extended by using thin film coatings such as titanium nitride (TiN). However, when errors arise in the coating process or when the tooling needs to be re-used it is necessary to remove the coating. Decoating is also useful when a large batch of cutting tools needs to be re-directed for a different application, which requires a new generation of coating. Existing technology uses chemical methods which are not environmentally friendly or ideal for selective removal. In this work, excimer laser striping of TiN from coated tungsten carbide (WC) micro-tools has been demonstrated as a viable alternative to chemical methods. Also, in order to raise the integrity of the decoating process and to make the process more accurate and reliable, two online monitoring systems were developed exploiting probe beam reflection (PBR) and laser plume emission spectroscopy (PES). The online monitoring system facilitated a simultaneous prediction of surface elements as coating layers are progressively removed and ensures better control over the laser irradiation process so as to avoid under or over stripping of the coating.

  5. PET imaging of in vivo caspase-3/7 activity following myocardial ischemia-reperfusion injury with the radiolabeled isatin sulfonamide analogue [18F]WC-4-116

    PubMed Central

    Thukkani, Arun K; Shoghi, Kooresh I; Zhou, Dong; Xu, Jinbin; Chu, Wenhua; Novak, Eric; Chen, Delphine L; Gropler, Robert J; Mach, Robert H

    2016-01-01

    The utility of [18F]WC-4-116, a PET tracer for imaging caspase-3 activation, was evaluated in an animal model of myocardial apoptosis. [18F]WC-4-116 was injected into rats at 3 hours after a 30 min period of ischemia induced by temporary occlusion of the left anterior descending coronary artery in Sprague-Dawley rats. [18F]WC-4-116 uptake was quantified by 1) autoradiography, 2) microPET imaging studies, and 3) post-PET biodistribution studies. MicroPET imaging also assessed uptake of the non-caspase-3-targeted tracer [18F]ICMT-18 at 3 hours postischemia. Enzyme assays and Western blotting assessed caspase-3 activation in both at-risk and not-at-risk regions. Caspase-3 enzyme activity increased in the at-risk but not in the not-at-risk myocardium. Quantitative autoradiographic analysis of [18F]WC-4-116 demonstrated nearly 2-fold higher uptake in the ischemia-reperfusion (IR) versus sham animals. [18F]WC-4-116 microPET imaging studies demonstrated that the IR animals was similarly elevated in relation to sham. [18F]ICMT-18 uptake did not increase in at-risk myocardium despite evidence of caspase-3 activation. Biodistribution studies with [18F]WC-4-116 confirmed the microPET findings. These data indicate that the caspase-3-PET tracer [18F]WC-4-116 can noninvasively image in vivo caspase activity during myocardial apoptosis and may be useful for clinical imaging in humans. PMID:27186438

  6. PET imaging of in vivo caspase-3/7 activity following myocardial ischemia-reperfusion injury with the radiolabeled isatin sulfonamide analogue [(18)F]WC-4-116.

    PubMed

    Thukkani, Arun K; Shoghi, Kooresh I; Zhou, Dong; Xu, Jinbin; Chu, Wenhua; Novak, Eric; Chen, Delphine L; Gropler, Robert J; Mach, Robert H

    2016-01-01

    The utility of [(18)F]WC-4-116, a PET tracer for imaging caspase-3 activation, was evaluated in an animal model of myocardial apoptosis. [(18)F]WC-4-116 was injected into rats at 3 hours after a 30 min period of ischemia induced by temporary occlusion of the left anterior descending coronary artery in Sprague-Dawley rats. [(18)F]WC-4-116 uptake was quantified by 1) autoradiography, 2) microPET imaging studies, and 3) post-PET biodistribution studies. MicroPET imaging also assessed uptake of the non-caspase-3-targeted tracer [(18)F]ICMT-18 at 3 hours postischemia. Enzyme assays and Western blotting assessed caspase-3 activation in both at-risk and not-at-risk regions. Caspase-3 enzyme activity increased in the at-risk but not in the not-at-risk myocardium. Quantitative autoradiographic analysis of [(18)F]WC-4-116 demonstrated nearly 2-fold higher uptake in the ischemia-reperfusion (IR) versus sham animals. [(18)F]WC-4-116 microPET imaging studies demonstrated that the IR animals was similarly elevated in relation to sham. [(18)F]ICMT-18 uptake did not increase in at-risk myocardium despite evidence of caspase-3 activation. Biodistribution studies with [(18)F]WC-4-116 confirmed the microPET findings. These data indicate that the caspase-3-PET tracer [(18)F]WC-4-116 can noninvasively image in vivo caspase activity during myocardial apoptosis and may be useful for clinical imaging in humans. PMID:27186438

  7. Demystifying Open Access

    SciTech Connect

    Mele, Salvatore

    2007-05-14

    The tenets of Open Access are to grant anyone, anywhere and anytime free access to the results of scientific research. HEP spearheaded the Open Access dissemination of scientific results with the mass mailing of preprints in the pre-WWW era and with the launch of the arXiv preprint system at the dawn of the '90s. The HEP community is now ready for a further push to Open Access while retaining all the advantages of the peer-review system and, at the same time, bring the spiralling cost of journal subscriptions under control. I will present a possible plan for the conversion to Open Access of HEP peer-reviewed journals, through a consortium of HEP funding agencies, laboratories and libraries: SCOAP3 (Sponsoring Consortium for Open Access Publishing in Particle Physics). SCOAP3 will engage with scientific publishers towards building a sustainable model for Open Access publishing, which is as transparent as possible for HEP authors. The current system in which journals income comes from subscription fees is replaced with a scheme where SCOAP3 compensates publishers for the costs incurred to organise the peer-review service and give Open Access to the final version of articles. SCOAP3 will be funded by all countries active in HEP under a 'fair share' scenario, according to their production of HEP articles. In this talk I will present a short overview of the history of Open Access in HEP, the details of the SCOAP3 model and the outlook for its implementation.

  8. Demystifying Open Access

    SciTech Connect

    Mele, Salvatore

    2007-05-14

    The tenets of Open Access are to grant anyone, anywhere and anytime free access to the results of scientific research. HEP spearheaded the Open Access dissemination of scientific results with the mass mailing of preprints in the pre-WWW era and with the launch of the arXiv preprint system at the dawn of the '90s. The HEP community is now ready for a further push to Open Access while retaining all the advantages of the peer-review system and, at the same time, bring the spiralling cost of journal subscriptions under control. I will present a possible plan for the conversion to Open Access of HEP peer-reviewed journals, through a consortium of HEP funding agencies, laboratories and libraries: SCOAP3 (Sponsoring Consortium for Open Access Publishing in Particle Physics). SCOAP3 will engage with scientific publishers towards building a sustainable model for Open Access publishing, which is as transparent as possible for HEP authors. The current system in which journals income comes from subscription fees is replaced with a scheme where SCOAP3 compensates publishers for the costs incurred to organise the peer-review service and give Open Access to the final version of articles. SCOAP3 will be funded by all countries active in HEP under a "fair share" scenario, according to their production of HEP articles. In this talk I will present a short overview of the history of Open Access in HEP, the details of the SCOAP3 model and the outlook for its implementation.

  9. Access Interface Strategies

    PubMed Central

    Fager, Susan; Beukelman, David R.; Fried-Oken, Melanie; Jakobs, Tom; Baker, John

    2013-01-01

    Individuals who rely on augmentative and alternative communication (AAC) devices to support their communication often have physical movement challenges that require alternative methods of access. Technology that supports access, particularly for those with the most severe movement deficits, have expanded substantially over the years. The purposes of this article are to review the state of the science of access technologies that interface with augmentative and alternative communication devices and to propose a future research and development agenda that will enhance access options for people with limited movement capability due to developmental and acquired conditions. PMID:22590797

  10. Pump/probe Microwave-Optical Double Resonance (ppmodr) Study of Tungsten Carbide (wc) and Platinum Carbide (PtC)

    NASA Astrophysics Data System (ADS)

    Wang, Fang; Steimle, Timothy C.

    2012-06-01

    Gas-phase metal-containing molecules serve as ideal venues for testing computational methodologies being developed to predict chemical properties of simple molecules. The most accurate determination of molecular properties comes from the analysis of pure rotational spectra, which for metal containing molecules can be difficult to obtain. One powerful method for recording pure rotational spectrum is to use the PPMODR technique which couples the sensitivity of optical detection with the precision of molecular beam microwave spectroscopy. Here we report on the application of PPMODR to the study of tungsten carbide, WC, and platinum carbide, PtC. The J=1→2 pure rotational transitions in the X^3Δ_1(v=0) state of ^1^8^6W^1^2C and ^1^8^4W^1^2C reveal a small splitting, an analysis of which provides accurate determination of the rotational and Ω-doubling parameters for the X^3Δ_1(v=0) state, which are critical to the proposed electron electric dipole moment experiments (eEDM). The implications for the proposed eEDM measurements will be presented. We also report on the J=0→1 and J=1→2 rotational transitions of PtC for the X^1Σ^+(v=0) state. The ^1^9^5Pt(I=1/2) nuclear spin-rotation interaction parameter, C_I^e^f^f , was determined to be 0.138(6) MHz. A comparison with other Pt-containing molecules and a proposed molecular orbital correlation diagram is given. W. J. Childs, Physics Reports 211, No. 3 (1991). F. Wang and T. C. Steimle, J. Chem. Phys. 136, 044312 (2012). J. Lee, E. R. Meyer, R. Paudel, J. L. Bohn and A. E. Leanhardt, J. Mod. Opt. 56 2005, (2009). F. Wang and T. C. Steimle, J. Chem. Phys. 134, 201106 (2011). F. Wang and T. C. Steimle, J. Chem. Phys. 135, 104313 (2011).

  11. In-situ investigation of laser surface modifications of WC-Co hard metals inside a scanning electron microscope

    NASA Astrophysics Data System (ADS)

    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.

  12. Optical Access Networks

    NASA Astrophysics Data System (ADS)

    Zheng, Jun; Ansari, Nirwan

    2005-05-01

    Call for Papers: Optical Access Networks With the wide deployment of fiber-optic technology over the past two decades, we have witnessed a tremendous growth of bandwidth capacity in the backbone networks of today's telecommunications infrastructure. However, access networks, which cover the "last-mile" areas and serve numerous residential and small business users, have not been scaled up commensurately. The local subscriber lines for telephone and cable television are still using twisted pairs and coaxial cables. Most residential connections to the Internet are still through dial-up modems operating at a low speed on twisted pairs. As the demand for access bandwidth increases with emerging high-bandwidth applications, such as distance learning, high-definition television (HDTV), and video on demand (VoD), the last-mile access networks have become a bandwidth bottleneck in today's telecommunications infrastructure. To ease this bottleneck, it is imperative to provide sufficient bandwidth capacity in the access networks to open the bottleneck and thus present more opportunities for the provisioning of multiservices. Optical access solutions promise huge bandwidth to service providers and low-cost high-bandwidth services to end users and are therefore widely considered the technology of choice for next-generation access networks. To realize the vision of optical access networks, however, many key issues still need to be addressed, such as network architectures, signaling protocols, and implementation standards. The major challenges lie in the fact that an optical solution must be not only robust, scalable, and flexible, but also implemented at a low cost comparable to that of existing access solutions in order to increase the economic viability of many potential high-bandwidth applications. In recent years, optical access networks have been receiving tremendous attention from both academia and industry. A large number of research activities have been carried out or

  13. Optical Access Networks

    NASA Astrophysics Data System (ADS)

    Zheng, Jun; Ansari, Nirwan; Jersey Inst Ansari, New; Jersey Inst, New

    2005-04-01

    Call for Papers: Optical Access Networks With the wide deployment of fiber-optic technology over the past two decades, we have witnessed a tremendous growth of bandwidth capacity in the backbone networks of today's telecommunications infrastructure. However, access networks, which cover the "last-mile" areas and serve numerous residential and small business users, have not been scaled up commensurately. The local subscriber lines for telephone and cable television are still using twisted pairs and coaxial cables. Most residential connections to the Internet are still through dial-up modems operating at a low speed on twisted pairs. As the demand for access bandwidth increases with emerging high-bandwidth applications, such as distance learning, high-definition television (HDTV), and video on demand (VoD), the last-mile access networks have become a bandwidth bottleneck in today's telecommunications infrastructure. To ease this bottleneck, it is imperative to provide sufficient bandwidth capacity in the access networks to open the bottleneck and thus present more opportunities for the provisioning of multiservices. Optical access solutions promise huge bandwidth to service providers and low-cost high-bandwidth services to end users and are therefore widely considered the technology of choice for next-generation access networks. To realize the vision of optical access networks, however, many key issues still need to be addressed, such as network architectures, signaling protocols, and implementation standards. The major challenges lie in the fact that an optical solution must be not only robust, scalable, and flexible, but also implemented at a low cost comparable to that of existing access solutions in order to increase the economic viability of many potential high-bandwidth applications. In recent years, optical access networks have been receiving tremendous attention from both academia and industry. A large number of research activities have been carried out or

  14. Optical Access Networks

    NASA Astrophysics Data System (ADS)

    Zheng, Jun; Ansari, Nirwan

    2005-06-01

    Call for Papers: Optical Access Networks With the wide deployment of fiber-optic technology over the past two decades, we have witnessed a tremendous growth of bandwidth capacity in the backbone networks of today's telecommunications infrastructure. However, access networks, which cover the "last-mile" areas and serve numerous residential and small business users, have not been scaled up commensurately. The local subscriber lines for telephone and cable television are still using twisted pairs and coaxial cables. Most residential connections to the Internet are still through dial-up modems operating at a low speed on twisted pairs. As the demand for access bandwidth increases with emerging high-bandwidth applications, such as distance learning, high-definition television (HDTV), and video on demand (VoD), the last-mile access networks have become a bandwidth bottleneck in today's telecommunications infrastructure. To ease this bottleneck, it is imperative to provide sufficient bandwidth capacity in the access networks to open the bottleneck and thus present more opportunities for the provisioning of multiservices. Optical access solutions promise huge bandwidth to service providers and low-cost high-bandwidth services to end users and are therefore widely considered the technology of choice for next-generation access networks. To realize the vision of optical access networks, however, many key issues still need to be addressed, such as network architectures, signaling protocols, and implementation standards. The major challenges lie in the fact that an optical solution must be not only robust, scalable, and flexible, but also implemented at a low cost comparable to that of existing access solutions in order to increase the economic viability of many potential high-bandwidth applications. In recent years, optical access networks have been receiving tremendous attention from both academia and industry. A large number of research activities have been carried out or

  15. Accessing the Microform Publication.

    ERIC Educational Resources Information Center

    Schindler, Stan

    1985-01-01

    Characterizes types of indexing programs used by Research Publications, Inc. and describes provision of access to four major projects: "The Official Washington Post Index" (provides access to newspaper and microfilm edition); "The Eighteenth Century"; "The Declassified Documents Reference System" (ongoing fiche project abstracted and indexed…

  16. ACCESS Pointing Control System

    NASA Technical Reports Server (NTRS)

    Brugarolas, Paul; Alexander, James; Trauger, John; Moody, Dwight; Egerman, Robert; Vallone, Phillip; Elias, Jason; Hejal, Reem; Camelo, Vanessa; Bronowicki, Allen; O'Connor, David; Partrick, Richard; Orzechowski, Pawel; Spitter, Connie; Lillie, Chuck

    2010-01-01

    ACCESS (Actively-Corrected Coronograph for Exoplanet System Studies) was one of four medium-class exoplanet concepts selected for the NASA Astrophysics Strategic Mission Concept Study (ASMCS) program in 2008/2009. The ACCESS study evaluated four major coronograph concepts under a common space observatory. This paper describes the high precision pointing control system (PCS) baselined for this observatory.

  17. Access to Higher Education

    ERIC Educational Resources Information Center

    Briscoe, Felecia; De Oliver, Miguel

    2006-01-01

    This case study researches the degree to which the location and services offered by a multicampus university, geographically situated consistent with the commercial principles of a large mass-market enterprise, facilitate access for educationally underserved groups. First, the necessity of democratizing educational access to an underprivileged…

  18. Intellectual Access to Images.

    ERIC Educational Resources Information Center

    Chen, Hsin-Liang; Rasmussen, Edie M.

    1999-01-01

    The increased availability of digital images is accompanied by a need for solutions to the problems inherent in indexing them for retrieval. Problems in image description and access are discussed, with a perspective on traditional and new solutions. Recent developments in intellectual access to images are surveyed and contrasted with…

  19. The Universal Access System.

    ERIC Educational Resources Information Center

    Scott, Neil G.

    This final report discusses the outcomes of a project that created a Universal Access System (UAS), a system that gives students with disabilities access to the same computers as their classmates. The project developed a new approach in which the needs of the individual with disabilities are handled separately from the computers and other devices…

  20. MedlinePlus: Accessibility

    MedlinePlus

    ... Tools Español You Are Here: Home → MedlinePlus Accessibility URL of this page: https://medlineplus.gov/accessibility.html ... or (301) 594-5983 and provide the address (URL) of the page on which you need assistance, ...

  1. Access and Technology

    ERIC Educational Resources Information Center

    Watson, Lemuel W.

    2004-01-01

    Community colleges are well positioned to provide underserved student populations with access to computer technology. This chapter explores the issues of access and technology from multiple perspectives in the community college, and explains how community colleges can develop a foundation for their technology plan.

  2. Improving School Access Control

    ERIC Educational Resources Information Center

    National Clearinghouse for Educational Facilities, 2008

    2008-01-01

    Few things are more important for school safety and security than controlling access to buildings and grounds. It is relatively easy to incorporate effective access control measures in new school designs but more difficult in existing schools, where most building and site features cannot be readily altered or reconfigured. The National…

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

    NASA Astrophysics Data System (ADS)

    Singh, Harpreet; Kaur, Manpreet; Prakash, Satya

    2016-06-01

    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.

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

    NASA Astrophysics Data System (ADS)

    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.

  5. Study of interface correlation in W/C multilayer structure by specular and non-specular grazing incidence X-ray reflectivity measurements

    SciTech Connect

    Biswas, A. Bhattacharyya, D.; Sahoo, N. K.; Maidul Haque, S.; Tripathi, S.; De, Rajnarayan; Rai, S.

    2015-10-28

    W/C/W tri-layer thin film samples have been deposited on c-Si substrates in a home-built Ion Beam Sputtering system at 1.5 × 10{sup −3} Torr Ar working pressure and 10 mA grid current. The tri-layer samples have been deposited at different Ar{sup +} ion energies between 0.6 and 1.2 keV for W layer deposition and the samples have been characterized by specular and non-specular grazing incidence X-ray reflectivity (GIXR) measurements. By analyzing the GIXR spectra, various interface parameters have been obtained for both W-on-C and C-on-W interfaces and optimum Ar{sup +} ion energy for obtaining interfaces with low imperfections has been found. Subsequently, multilayer W/C samples with 5-layer, 7-layer, 9-layer, and 13-layer have been deposited at this optimum Ar{sup +} ion energy. By fitting the specular and diffused GIXR data of the multilayer samples with the parameters of each interface as fitting variables, different interface parameters, viz., interface width, in-plane correlation length, interface roughness, and interface diffusion have been estimated for each interface and their variation across the depth of the multilayers have been obtained. The information would be useful in realizing W/C multilayers for soft X-ray mirror application in the <100 Å wavelength regime. The applicability of the “restart of the growth at the interface” model in the case of these ion beam sputter deposited W/C multilayers has also been investigated in the course of this study.

  6. Mathematical modelling in Matlab of the experimental results shows the electrochemical potential difference - temperature of the WC coatings immersed in a NaCl solution

    NASA Astrophysics Data System (ADS)

    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.

  7. Optical Zeeman spectroscopy of the [17.6]2-X3Δ1(1,0) band system of tungsten monocarbide, WC

    NASA Astrophysics Data System (ADS)

    Wang, Fang; Steimle, Timothy C.

    2011-09-01

    The Zeeman effect in the [17.6]2-X3Δ1(1,0) band system of tungsten monocarbide, WC, has been recorded and analyzed. Magnetic tuning of the spectral features recorded at high resolution (full width at half maximum ≅ 35 MHz) and at field strengths of 1101 and 2230 G are accurately modeled using an effective Zeeman Hamiltonian. The observed spectra were fit to produce gel -factors for the X3Δ1(υ = 0) and [17.6]2(υ = 1) states. The observed gel-factors are discussed in terms of the proposed electronic state distribution.

  8. Automatic image analysis methods for the determination of stereological parameters - application to the analysis of densification during solid state sintering of WC-Co compacts

    PubMed

    Missiaen; Roure

    2000-08-01

    Automatic image analysis methods which were used to determine microstructural parameters of sintered materials are presented. Estimation of stereological parameters at interfaces, when the system contains more than two phases, is particularly detailed. It is shown that the specific surface areas and mean curvatures of the various interfaces can be estimated in the numerical space of the images. The methods are applied to the analysis of densification during solid state sintering of WC-Co compacts. The microstructural evolution is commented on. Application of microstructural measurements to the analysis of densification kinetics is also discussed. PMID:10947907

  9. Optical Access Networks

    NASA Astrophysics Data System (ADS)

    Zheng, Jun; Ansari, Nirwan

    2005-03-01

    Call for Papers: Optical Access Networks With the wide deployment of fiber-optic technology over the past two decades, we have witnessed a tremendous growth of bandwidth capacity in the backbone networks of today's telecommunications infrastructure. However, access networks, which cover the "last-mile" areas and serve numerous residential and small business users, have not been scaled up commensurately. The local subscriber lines for telephone and cable television are still using twisted pairs and coaxial cables. Most residential connections to the Internet are still through dial-up modems operating at a low speed on twisted pairs. As the demand for access bandwidth increases with emerging high-bandwidth applications, such as distance learning, high-definition television (HDTV), and video on demand (VoD), the last-mile access networks have become a bandwidth bottleneck in today's telecommunications infrastructure. To ease this bottleneck, it is imperative to provide sufficient bandwidth capacity in the access networks to open the bottleneck and thus present more opportunities for the provisioning of multiservices. Optical access solutions promise huge bandwidth to service providers and low-cost high-bandwidth services to end users and are therefore widely considered the technology of choice for next-generation access networks. To realize the vision of optical access networks, however, many key issues still need to be addressed, such as network architectures, signaling protocols, and implementation standards. The major challenges lie in the fact that an optical solution must be not only robust, scalable, and flexible, but also implemented at a low cost comparable to that of existing access solutions in order to increase the economic viability of many potential high-bandwidth applications. In recent years, optical access networks have been receiving tremendous attention from both academia and industry. A large number of research activities have been carried out or

  10. Multiple Access Trade Study

    NASA Technical Reports Server (NTRS)

    Motamedi, Masoud

    1990-01-01

    The Personal Access Satellite System (PASS) strawman design uses a hybrid Time Division Multiple Access (TDMA)/Frequency Division Multiple Access (FDMA) implementation. TDMA is used for the forward direction (from Suppliers to Users), and FDMA for the return direction (from Users to Suppliers). An alternative architecture is proposed that will require minimal real time coordination and yet provide a fast access method by using random access Code Division Multiple Access (CDMA). The CDMA system issues are addressed such as connecting suppliers and users, both of whom may be located anywhere in the CONUS, when the user terminals are constrained in size and weight; and providing efficient traffic routing under highly variable traffic requirements. It is assumed that bandwidth efficiency is not of paramount importance. CDMA or Spread Spectrum Multiple Access (SSMA) communication is a method in which a group of carriers operate at the same nominal center frequency but are separable from each other by the low cross correlation of the spreading codes used. Interference and multipath rejection capability, ease of selective addressing and message screening, low density power spectra for signal hiding and security, and high resolution ranging are among the benefits of spread spectrum communications.

  11. The role of bovine γδ T cells and their WC1 co-receptor in response to bacterial pathogens and promoting vaccine efficacy: a model for cattle and humans.

    PubMed

    Baldwin, Cynthia L; Hsu, Haoting; Chen, Chuang; Palmer, Mitchell; McGill, Jodi; Waters, W Ray; Telfer, Janice C

    2014-06-15

    γδ T cells are critical to immune surveillance and protection since they are found as resident cells in many organs and tissues, including in humans and ruminants, and circulate at substantial numbers in the blood. It is known that γδ T cells contribute to cellular immunity and protection against important pathogens including organizing granulomas in response to Mycobacteria. We have shown that IFNγ-producing bovine γδ T cells bearing the WC1 co-receptor are the major cell population responding in recall responses to Leptospira during the first month following priming by vaccination against serovar Hardjo. To date, successful vaccines largely include those to diseases that only require antibody responses for protection and attempts at creating subunit peptide vaccines to stimulate conventional αβ T cells for cellular immune responses have been mostly unsuccessful. However, activation of nonconventional T cells, such as γδ T cells that direct adaptive T cell responses, has received little attention for improving vaccines because it is not clear how best to prime γδ T cells for recall responses. Annotation of the bovine genome showed there were 13 WC1 molecules coded for by individual genes. This gene number is conserved among breeds and individuals and expression of the WC1 molecules are distributed among cells to form a number of γδ T cell subsets. Using RNA silencing, we have shown that the WC1 co-receptor contributes to the ability of γδ T cells to respond to Leptospira spp. The Leptospira-responsive γδ T cells are found within a subset of the serologically defined WC1.1(+) γδ T cell subpopulation and our data indicate that the WC1 molecules expressed act as pattern recognition receptors interacting directly with bacterial components. We are now extending this work to Mycobacteria bovis. PMID:24726858

  12. Optical Access Networks

    NASA Astrophysics Data System (ADS)

    Zheng, Jun; Ansari, Nirwan

    2005-01-01

    Call for Papers: Optical Access Networks

    Guest Editors Jun Zheng, University of Ottawa Nirwan Ansari, New Jersey Institute of Technology

    Submission Deadline: 1 June 2005

    Background

    With the wide deployment of fiber-optic technology over the past two decades, we have witnessed a tremendous growth of bandwidth capacity in the backbone networks of today's telecommunications infrastructure. However, access networks, which cover the "last-mile" areas and serve numerous residential and small business users, have not been scaled up commensurately. The local subscriber lines for telephone and cable television are still using twisted pairs and coaxial cables. Most residential connections to the Internet are still through dial-up modems operating at a low speed on twisted pairs. As the demand for access bandwidth increases with emerging high-bandwidth applications, such as distance learning, high-definition television (HDTV), and video on demand (VoD), the last-mile access networks have become a bandwidth bottleneck in today's telecommunications infrastructure. To ease this bottleneck, it is imperative to provide sufficient bandwidth capacity in the access networks to open the bottleneck and thus present more opportunities for the provisioning of multiservices. Optical access solutions promise huge bandwidth to service providers and low-cost high-bandwidth services to end users and are therefore widely considered the technology of choice for next-generation access networks. To realize the vision of optical access networks, however, many key issues still need to be addressed, such as network architectures, signaling protocols, and implementation standards. The major challenges lie in the fact that an optical solution must be not only robust, scalable, and flexible, but also implemented at a low cost comparable to that of existing access solutions in order to increase the

  13. The Structure of W/C (0.15 < γ < 0.8) Multilayers Annealed in Argon or Air.

    PubMed

    Gonzalez-Hernandez, J; Chao, B S; Ovshinsky, S R; Allred, D D

    1996-01-01

    We report the effect that thermal annealing in inert and oxidizing atmospheres, and with and without encapsulating layers, has on the structure of tungsten/carbon [W/C] multilayer thin films. This study focuses on the tungsten component and deals mainly with multilayers where the ratio of thickness of tungsten layers is equal to or greater than for the carbon layers (that is, γ ≤ 0.5). This is in contrast to prior studies where the tungsten layer thickness was generally held constant and the carbon layer was varied. Thermal annealing in inert atmospheres produces reactions and other structural changes in the tungsten and carbide layers which depend on the as-deposited multilayer structure which depends, in turn, on the thickness of the tungsten layer. In samples where both the tungsten and carbide fractions of the multilayer are completely amorphous as deposited, which is the case for thin tungsten layers (thickness of tungsten (tw) < 4 nm/period), the reactions in the tungsten layer forming crystalline tungsten and tungsten carbide occur at annealing temperatures above 900°C. The layer pair spacing, or period, (d), in this group shows an expansion of up to 10-15% of the original value as has been reported in the past. Changes in both the tungsten and carbide layers, and their interfaces, contribute to changes in d spacing and relative thickness of the high and low Z components. When the tungsten layer thickness exceeds 4 nm per period the tungsten is partially crystallized in as-prepared samples. In such multilayers interfacial reactions, producing an oriented partially crystalline W2C/C superlattice, occur at temperatures of 600°C and below. The fact that W2C crystallites in one period can form a structure which is correlated to W2C crystallites in neighboring layers is somewhat surprising, since layers are presumably still separated by amorphous carbon which is still visible via Raman. The expansion of the layer pair spacing is relatively small (<5%) in

  14. HRP Data Accessibility 2009

    NASA Video Gallery

    Dr. Clarence Sams spoke at the 2009 Human Research Program's Investigators Workshop on the current status of Data Accessibility. In this presentation he discusses the content of the Human Life Scie...

  15. Critical Access Hospitals (CAH)

    MedlinePlus

    ... CAH Conditions of Participation . What are the location requirements for CAH status? Critical Access Hospitals must be ... clinic that does not meet the CAH distance requirements? As of January 1, 2008, all CAHs, including ...

  16. Computer memory access technique

    NASA Technical Reports Server (NTRS)

    Zottarelli, L. J.

    1967-01-01

    Computer memory access commutator and steering gate configuration produces bipolar current pulses while still employing only the diodes and magnetic cores of the classic commutator, thereby appreciably reducing the complexity of the memory assembly.

  17. Adapting Web Browsers for Accessibility.

    ERIC Educational Resources Information Center

    Hendrix, Paul; Birkmire, Mike

    This paper examines ways to make World Wide Web browsers accessible for individuals with disabilities, and through them, gain access to the information on the Web. It discusses which browsers can be made more accessible and evaluates different types of input. Mouse access, keyboard access, and voice input are reviewed. Processing aids, such as…

  18. Optical Access Networks

    NASA Astrophysics Data System (ADS)

    Zheng, Jun; Ansari, Nirwan

    2005-02-01

    Call for Papers: Optical Access Networks With the wide deployment of fiber-optic technology over the past two decades, we have witnessed a tremendous growth of bandwidth capacity in the backbone networks of today's telecommunications infrastructure. However, access networks, which cover the "last-mile" areas and serve numerous residential and small business users, have not been scaled up commensurately. The local subscriber lines for telephone and cable television are still using twisted pairs and coaxial cables. Most residential connections to the Internet are still through dial-up modems operating at a low speed on twisted pairs. As the demand for access bandwidth increases with emerging high-bandwidth applications, such as distance learning, high-definition television (HDTV), and video on demand (VoD), the last-mile access networks have become a bandwidth bottleneck in today's telecommunications infrastructure. To ease this bottleneck, it is imperative to provide sufficient bandwidth capacity in the access networks to open the bottleneck and thus present more opportunities for the provisioning of multiservices. Optical access solutions promise huge bandwidth to service providers and low-cost high-bandwidth services to end users and are therefore widely considered the technology of choice for next-generation access networks. To realize the vision of optical access networks, however, many key issues still need to be addressed, such as network architectures, signaling protocols, and implementation standards. The major challenges lie in the fact that an optical solution must be not only robust, scalable, and flexible, but also implemented at a low cost comparable to that of existing access solutions in order to increase the economic viability of many potential high-bandwidth applications. In recent years, optical access networks have been receiving tremendous attention from both academia and industry. A large number of research activities have been carried out or

  19. Effect of composition and corrosion properties of the metallic matrix on the erosion-corrosion behavior of HVOF sprayed WC-coatings

    SciTech Connect

    Rogne, T.; Solem, T.; Berget, J.

    1998-12-31

    In corrosive media the wear resistance of ceramic-metallic coatings is dependent on the corrosion resistance of the metal matrix. Other factors that will affect the coating deterioration are the corrosivity of the medium and any galvanic interaction from the surrounding material. This paper presents results from a study where different types of WC(Co/Cr/Mo/Ni) powders have been sprayed by HVOF, Diamond Jet 2600 Hybrid equipment. The properties of the sprayed coatings have been verified by metallographic studies and by erosion-corrosion testing both under corrosive and non-corrosive conditions. The results clearly demonstrate the importance of having a metal matrix at least as corrosion resistance as the surrounding materials. When wear exposed components in pipe systems, pumps or valves are coated with a WC type coating, the corrosion resistance of the metal matrix should be compatible to the material of the rest of the system. This is especially important when the surrounding materials are corrosion resistant alloys as stainless steels, where the coatings otherwise will act as an anode. This work is relevant for field production equipment in the oil and gas industry.

  20. Mechanical property changes in HVOF sprayed nano-structured WC-17wt.%Ni(80/20)Cr coating with varying substrate roughness

    NASA Astrophysics Data System (ADS)

    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.

  1. Effect of Spray Particle Velocity on Cavitation Erosion Resistance Characteristics of HVOF and HVAF Processed 86WC-10Co4Cr Hydro Turbine Coatings

    NASA Astrophysics Data System (ADS)

    Kumar, R. K.; Kamaraj, M.; Seetharamu, S.; Pramod, T.; Sampathkumaran, P.

    2016-06-01

    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.

  2. Delamination Strength of WC-Co Thermal-Sprayed Coating Under Combined Stresses by Torsion-Tension Pin-Test Method

    NASA Astrophysics Data System (ADS)

    Kaneko, Kenji; Higaki, Keitaro

    2014-08-01

    In this report, the delamination strength of WC -Co thermal-sprayed coatings under combined torsion and tension is evaluated using a newly developed method, which is called the torsion -tension pin-test. First, the effects of both the pin diameter and the coating thickness on the apparent delamination strength were investigated experimentally. Second, the stress distributions around the interface edge between the pin and the coating were numerically obtained by using the finite element analysis program "MARC." It was confirmed that the fractured plane of the torsion pin coincides with the interfacial plane between the coating and the pin. The apparent delamination strength obtained experimentally decreased linearly with increasing pin diameter and increased with increasing coating thickness t, but it was stable at t of 400 μm or more. The shear delamination strength decreased with increasing tensile stress. Similar stress distributions were observed at the interface when delaminations occurred for rather thick coatings, independent of the pin diameter. The critical combination of the strength of shear stress fields ( Ks) with that of tensile stress fields ( Ka), i.e., the delamination criteria of the coating under combined shear and tensile loadings, was obtained for a WC-12Co thermal-sprayed coating. These combinations were found to be independent of pin diameter and coating thickness.

  3. Effects of coating thickness and interfacial roughness on cracking and delamination strength of WC-Co coating measured by ring compression test

    NASA Astrophysics Data System (ADS)

    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.

  4. Influence of the Spray Angle on the Properties of HVOF Sprayed WC-Co Coatings Using (-10 + 2 μm) Fine Powders

    NASA Astrophysics Data System (ADS)

    Tillmann, W.; Baumann, I.; Hollingsworth, P.; Laemmerhirt, I.-A.

    2013-03-01

    The application of fine powders in thermal spray technology represents an innovative approach to apply dense and smooth near-net shape coatings on tools with complex geometry. However, this aim can only be achieved as long as the influence of the handling parameters of the spray process, such as the spray angle, is sufficiently understood. In this study, the influence of the spray angle on the deposition rate as well as on the coating properties (microhardness, roughness, and porosity) of HVOF-sprayed, fine-structured coatings are investigated. A fine, agglomerated, and sintered WC-12Co powder (agglomerate size: 2-10 μm, WC-particle Fisher sub-sieve size = 400 nm) was used as feedstock material. It has been shown that HVOF spraying of fine powders is less susceptible to an alteration of the spray angle than most other thermal spray processes such as plasma- or arc-spraying. The reduction of the spray angle results in a decrease in the deposition rate, while no significant degradation of the coating properties is found up to 30°. However, at spray angles below 30° the coating strength is negatively affected by the formation of pores and cracks.

  5. Ultrasonic cavitation erosion of high-velocity oxygen-fuel (HVOF) sprayed near-nanostructured WC-10Co-4Cr coating in NaCl solution.

    PubMed

    Hong, Sheng; Wu, Yuping; Zhang, Jianfeng; Zheng, Yugui; Qin, Yujiao; Lin, Jinran

    2015-09-01

    The high-velocity oxygen-fuel (HVOF) spraying process was used to prepare near-nanostructured WC-10Co-4Cr coating. The cavitation erosion behavior and mechanism of the coating in 3.5 wt.% NaCl solution were analyzed in detail. The results showed that the amorphous phase and WC grain were present in the coating. The cavitation erosion resistance of the coating was about 1.27 times that of the stainless steel 1Cr18Ni9Ti under the same testing conditions. The effects of erosion time on the microstructural evolution were discussed. It was revealed that cracks initiated at the edge of pre-existing pores and propagated along the carbide-binder interface, leading to the pull-out of carbide particle and the formation of pits and craters on the surface. The main failure mechanism of the coating was erosion of the binder phases, brittle detachment of hard phases and formation of pitting corrosion products. PMID:25617967

  6. Injury risk of a 6-year-old wheelchair-seated occupant in a frontal motor vehicle impact--'ANSI/RESNA WC-19' sled testing analysis.

    PubMed

    Ha, DongRan; Bertocci, Gina

    2007-09-01

    Children with disabilities are transported on a daily basis to schools and developmental facilities. When they travel, they often remain seated in their wheelchairs in vehicles. To study injury risk of pediatric wheelchair users in motor vehicle crashes, three of the same pediatric manual wheelchairs were sled impact tested with a seated Hybrid III 6-year-old ATD using a 20 g/48 km/h frontal crash pulse. The sled test results were compared to kinematic limitations and injury criteria specified in the ANSI/RESNA WC-19, FMVSS 213 and FMVSS 208. All sled test results were below the limits specified in the ANSI/RESNA WC-19 standard and FMVSS 213. All tests exceeded the N(ij) limit of 1 specified in FMVSS 208, and one test exceeded the limit of peak neck tension force. Chest deflection resulting from one of three tests was at the limit specified in FMVSS 208. Our results suggest that children with disabilities who remain seated in their wheelchairs in vehicles may be at risk of neck injury in a frontal impact motor vehicle crash. However, limitations in the biofidelity of the Hybrid III ATD neck raise concern as to the translatability of these findings to the real world. Additional studies are needed to investigate the influence of neck properties and ATD neck biofidelity on injury risk of children who travel seated in their wheelchairs. PMID:17251048

  7. Effect of Spray Particle Velocity on Cavitation Erosion Resistance Characteristics of HVOF and HVAF Processed 86WC-10Co4Cr Hydro Turbine Coatings

    NASA Astrophysics Data System (ADS)

    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.

  8. Mobile multiple access study

    NASA Technical Reports Server (NTRS)

    1977-01-01

    Multiple access techniques (FDMA, CDMA, TDMA) for the mobile user and attempts to identify the current best technique are discussed. Traffic loading is considered as well as voice and data modulation and spacecraft and system design. Emphasis is placed on developing mobile terminal cost estimates for the selected design. In addition, design examples are presented for the alternative techniques of multiple access in order to compare with the selected technique.

  9. Vascular Access in Children

    SciTech Connect

    Krishnamurthy, Ganesh Keller, Marc S.

    2011-02-15

    Establishment of stable vascular access is one of the essential and most challenging procedures in a pediatric hospital. Many clinical specialties provide vascular service in a pediatric hospital. At the top of the 'expert procedural pyramid' is the pediatric interventional radiologist, who is best suited and trained to deliver this service. Growing awareness regarding the safety and high success rate of vascular access using image guidance has led to increased demand from clinicians to provide around-the-clock vascular access service by pediatric interventional radiologists. Hence, the success of a vascular access program, with the pediatric interventional radiologist as the key provider, is challenging, and a coordinated multidisciplinary team effort is essential for success. However, there are few dedicated pediatric interventional radiologists across the globe, and also only a couple of training programs exist for pediatric interventions. This article gives an overview of the technical aspects of pediatric vascular access and provides useful tips for obtaining vascular access in children safely and successfully using image guidance.

  10. Access to health care

    PubMed Central

    Fortin, Martin; Maltais, Danielle; Hudon, Catherine; Lapointe, Lise; Ntetu, Antoine Lutumba

    2005-01-01

    OBJECTIVE To explore access to health care for patients presenting with multiple chronic conditions and to identify barriers and factors conducive to access. DESIGN Qualitative study with focus groups. SETTING Family practice unit in Chicoutimi (Saguenay), Que. PARTICIPANTS Twenty-five male and female adult patients with at least four chronic conditions but no cognitive disorders or decompensating conditions. METHODS For this pilot study, only three focus group discussions were held. MAIN FINDINGS The main barriers to accessing follow-up appointments included long waits on the telephone, automated telephone-answering systems, and needing to attend at specific times to obtain appointments. The main barriers to specialized care were long waiting times and the need to get prescriptions and referrals from family physicians. Factors reported conducive to access included systematic callbacks and the personal involvement of family physicians. Good communication between family physicians and specialists was also perceived to be an important factor in access. CONCLUSION Systematic callbacks, family physicians’ personal efforts to obtain follow-up visits, and better physician-specialist communication were all suggested as ways to improve access to care for patients with multiple chronic conditions. PMID:16926944

  11. Advanced access appointments

    PubMed Central

    Hudec, John C.; MacDougall, Steven; Rankin, Elaine

    2010-01-01

    ABSTRACT OBJECTIVE To examine the effects of advanced access (same-day physician appointments) on patient and provider satisfaction and to determine its association with other variables such as physician income and patient emergency department use. DESIGN Patient satisfaction survey and semistructured interviews with physicians and support staff; analysis of physician medical insurance billings and patient emergency department visits. SETTING Cape Breton, NS. PARTICIPANTS Patients, physicians, and support staff of 3 comparable family physician practices that had not implemented advanced access and an established advanced access practice. MAIN OUTCOME MEASURES Self-reported provider and patient satisfaction, physician office income, and patients’ emergency department use. RESULTS The key benefits of implementation of advanced access were an increase in provider and patient satisfaction levels, same or greater physician office income, and fewer less urgent (triage level 4) and nonurgent (triage level 5) emergency department visits by patients. CONCLUSION Currently within the Central Cape Breton Region, 33% of patients wait 4 or more days for urgent appointments. Findings from this study can be used to enhance primary care physician practice redesign. This research supports many benefits of transitioning to an advanced access model of patient booking. PMID:20944024

  12. ISDC Data Access Layer

    NASA Astrophysics Data System (ADS)

    Jennings, D.; Borkowski, J.; Contessi, T.; Lock, T.; Rohlfs, R.; Walter, R.

    The ISDC Data Access Layer (DAL) is an ANSI C and \\fortran 90 compatible library under development in support of the ESA INTEGRAL mission data analysis software. DALs primary purpose is to isolate the analysis software from the specifics of the data formats while at the same time providing new data abstraction and access capabilities. DAL supports the creation and manipulation of hierarchical data sets which may span multiple files and, in theory, multiple computer systems. A number of Application Programming Interfaces (APIs) are supported by DAL that allow software to view and access data at different levels of complexity. DAL also allows data sets to reside on disk, in conventional memory or in shared memory in a way that is transparent to the user/application.

  13. Bovine WC1- gamma delta T-cells incubated with IL-15 express the natural cytotoxicity receptor CD335 (NKp46) and produce IFN-gamma in response to exogenous IL-12 and IL-18

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The gamma delta T-cells of ruminants are believed to participate in innate immunity and have been described with regulatory and cytotoxic functions. Here we describe a subset of CD3+ TcRr1+ Wc1- CD8+ CD2+ gamma delta T-cells expressing CD335 (NKp46), classically associated with CD3- NK cells, as a c...

  14. Access to space studies

    NASA Technical Reports Server (NTRS)

    Martin, James A.

    1993-01-01

    The National Aeronautics and Space Administration is currently considering possible directions in Earth-to-orbit vehicle development under a study called 'Access to Space.' This agency-wide study is considering commercial launch vehicles, human transportation, space station logistics, and other space transportation requirements over the next 40 years. Three options are being considered for human transportation: continued use of the Space Shuttle; development of a small personnel carrier (personnel logistics system (PLS)); or development of an advanced vehicle such as a single-stage-to-orbit (SSTO). Several studies related to the overall Access to Space study are reported in this document.

  15. Accessibility | Smokefree.gov

    Cancer.gov

    Smokefree.gov is committed to providing access to all individuals—disabled or not—who are seeking information on its Web sites. To provide this information, the smokefree.gov Web site has been designed to comply with Section 508 of the Rehabilitation Act (as amended). Section 508 requires that all individuals with disabilities (whether they are federal government employees or members of the general public) have access to and use of information and data comparable to that provided to individuals without disabilities, unless an undue burden would be imposed.

  16. Migrants' access to healthcare.

    PubMed

    Norredam, Marie

    2011-10-01

    There are strong pragmatic and moral reasons for receiving societies to address access to healthcare for migrants. Receiving societies have a pragmatic interest in sustaining migrants' health to facilitate integration; they also have a moral obligation to ensure migrants' access to healthcare according to international human rights principles. The intention of this thesis is to increase the understanding of migrants' access to healthcare by exploring two study aims: 1) Are there differences in migrants' access to healthcare compared to that of non-migrants? (substudy I and II); and 2) Why are there possible differences in migrants' access to healthcare compared to that of non-migrants? (substudy III and IV). The thesis builds on different methodological approaches using both register-based retrospective cohort design, cross-sectional design and survey methods. Two different measures of access were used to explore differences: 1) cancer stage at diagnosis as a clinical outcome and 2) emergency room (ER) contacts as a utilisation measure. Both informal and formal barriers to access were studied to explore why possible differences existed including: 1) motivation for using ER; and 2) asylum seekers' healthcare entitlements. Different definitions of migration and ethnicity were investigated including: country of birth and residence status. Substudy I showed a tendency towards more advanced stage at diagnosis or unknown stage among most subgroups of migrant women with a history of cancer compared to non-migrant women. Sub-study II found that some migrants (those born in Somalia, Turkey and Ex-Yugoslavia) use ER services more frequently than do non-migrants whereas others have the same or lower utilisation levels. As a consequence, substudy III was undertaken, which documented that more migrant within all subgroups had considered contacting a primary caregiver before visiting the ER compared to non-migrants, but that migrants experienced communication problems herein

  17. Digital Scholarship and Open Access

    ERIC Educational Resources Information Center

    Losoff, Barbara; Pence, Harry E.

    2010-01-01

    Open access publications provide scholars with unrestricted access to the "conversation" that is the basis for the advancement of knowledge. The large number of open access journals, archives, and depositories already in existence demonstrates the technical and economic viability of providing unrestricted access to the literature that is the…

  18. Unique Access to Learning

    ERIC Educational Resources Information Center

    Goble, Don

    2009-01-01

    This article describes the many learning opportunities that broadcast technology students at Ladue Horton Watkins High School in St. Louis, Missouri, experience because of their unique access to technology and methods of learning. Through scaffolding, stepladder techniques, and trial by fire, students learn to produce multiple television programs,…

  19. Internet 2 Access Grid.

    ERIC Educational Resources Information Center

    Simco, Greg

    2002-01-01

    Discussion of the Internet 2 Initiative, which is based on collaboration among universities, businesses, and government, focuses on the Access Grid, a Computational Grid that includes interactive multimedia within high-speed networks to provide resources to enable remote collaboration among the research community. (Author/LRW)

  20. A matter of access

    PubMed Central

    Hu, Zheng; Chen, Kaifu; Li, Wei; Tyler, Jessica K

    2014-01-01

    The mechanism whereby transcriptional activators facilitate transcription activation has been debated. Our recent genome-wide profiling of gene expression during aging, where nucleosomes are depleted, indicates that the function of seemingly all transcriptional activators is to trigger nucleosome disassembly from promoters to allow the general transcription machinery access to the DNA. PMID:25764221