WorldWideScience

Sample records for playground surfaces reduce

  1. Protective Surfacing for Playgrounds.

    Science.gov (United States)

    Frost, Joe L.

    Noting that 90 percent of serious playground injuries result from falls to hard surfaces, this paper reviews the advantages and disadvantages of various playground surfacing materials in terms of cost, climate, durability, aesthetics, and play value. Findings are based on the personal experience of the author, government documents, laboratory…

  2. Preventing playground injuries.

    Science.gov (United States)

    Fuselli, Pamela; Yanchar, Natalie L

    2012-06-01

    With concerns increasing around childhood obesity and inactivity, playgrounds offer a chance for children to be active. But playgrounds also have risks, with injuries from falls being the most common. Research has shown that playground injuries can be reduced by lowering the heights of play equipment and using soft, deep surfaces to cushion falls. The Canadian Standards Association has published voluntary standards for playgrounds to address these risks for several years. Parents can further reduce injury risks by following simple playground strategies. This statement outlines the burden of playground injuries. It also provides parents and health care providers with opportunities to reduce injury incidence and severity through education and advocacy, and to implement evidence-informed safety standards and safer play strategies in local playgrounds. This document replaces a previous Canadian Paediatric Society position statement published in 2002.

  3. Analysis of energy flow during playground surface impacts.

    Science.gov (United States)

    Davidson, Peter L; Wilson, Suzanne J; Chalmers, David J; Wilson, Barry D; Eager, David; McIntosh, Andrew S

    2013-10-01

    The amount of energy dissipated away from or returned to a child falling onto a surface will influence fracture risk but is not considered in current standards for playground impact-attenuating surfaces. A two-mass rheological computer simulation was used to model energy flow within the wrist and surface during hand impact with playground surfaces, and the potential of this approach to provide insights into such impacts and predict injury risk examined. Acceleration data collected on-site from typical playground surfaces and previously obtained data from children performing an exercise involving freefalling with a fully extended arm provided input. The model identified differences in energy flow properties between playground surfaces and two potentially harmful surface characteristics: more energy was absorbed by (work done on) the wrist during both impact and rebound on rubber surfaces than on bark, and rubber surfaces started to rebound (return energy to the wrist) while the upper limb was still moving downward. Energy flow analysis thus provides information on playground surface characteristics and the impact process, and has the potential to identify fracture risks, inform the development of safer impact-attenuating surfaces, and contribute to development of new energy-based arm fracture injury criteria and tests for use in conjunction with current methods.

  4. Playgrounds.

    Science.gov (United States)

    Frost, Joe L.; And Others

    1997-01-01

    This collection of seven articles focuses on playgrounds, looking at such issues as the importance of play in child development, playground injuries and safety (including international playground safety), community playground improvement projects, and shock-absorbing playground surfaces. (SM)

  5. School playground surfacing and arm fractures in children: a cluster randomized trial comparing sand to wood chip surfaces.

    Directory of Open Access Journals (Sweden)

    Andrew W Howard

    2009-12-01

    Fibar and seven schools randomized to sand that installed sand. Noncompliant schools were added to the analysis to complete a cohort type analysis by treatment received (two schools that were randomized to Fibar but installed sand and seven schools that were randomized to sand but installed Fibar. Among compliant schools, an arm fracture rate of 1.9 (95% confidence interval [CI] 0.04-6.9 per 100,000 student-months was observed for falls into sand, compared with an arm fracture rate of 9.4 (95% CI 3.7-21.4 for falls onto Fibar surfaces (p< or =0.04905. Among all schools, the arm fracture rate was 4.5 (95% CI 0.26-15.9 per 100,000 student-months for falls into sand compared with 12.9 (95% CI 5.1-30.1 for falls onto Fibar surfaces. No serious head injuries and no fatalities were observed in either group.Granitic sand playground surfaces reduce the risk of arm fractures from playground falls when compared with engineered wood fibre surfaces. Upgrading playground surfacing standards to reflect this information will prevent arm fractures.Current Controlled Trials ISRCTN02647424.

  6. Effects of ground surface decontamination on the air radiation dose rate. Results of a decontamination trial at a playground lot in a Fukushima residential area

    International Nuclear Information System (INIS)

    Tagawa, Akihiro

    2012-01-01

    The Japan Atomic Energy Agency decontaminated schools, playgrounds, swimming pools, and houses in nonevacuated, less-contaminated areas in Fukushima for environmental restoration. A small, 150 m 2 playground lot in the residential area was chosen for decontamination demonstration, which used routinely available tools and commodities to carry out the work. The surfaces of playground lot equipment, such as swings, slides, and horizontal iron bars, were completely decontaminated by brushing with water and/or detergent. Side gutters around the playground lot were cleaned by removing the mud and then brushed and washed with a high-pressure water jet (7 MPa). The air dose rate at the playground lot was dominated by radiation from the ground surface and adjacent surroundings, such as apartments and rice fields. Two or three centimeters of the surface soil contaminated with cesium was removed manually with shovels, hoes, and other gardening tools. This significantly reduced the average air dose rate of the entire playground lot from 1.5 μSv/h before decontamination to 0.6 μSv/h. These results showed that ground surface decontamination can contribute measurably to the reduction in air dose rate in relatively small areas in residential areas. (author)

  7. A Handbook for Public Playground Safety. Volume II: Technical Guidelines for Equipment and Surfacing.

    Science.gov (United States)

    Consumer Product Safety Commission, Washington, DC.

    This handbook suggests safety guidelines for public playground equipment and describes various surfaces used under the equipment and possible injuries resulting from falls. The handbook is intended for use mainly by manufacturers, installers, school and park officials, and others interested in technical criteria for public playground equipment.…

  8. Addressing the issue of falls off playground equipment: an empirically-based intervention to reduce fall-risk behaviors on playgrounds.

    Science.gov (United States)

    Morrongiello, Barbara A; Matheis, Shawn

    2007-08-01

    The present study evaluated the impact of an intervention to reduce fall-risk behaviors on playgrounds among children 6-11 years of age. Children completed posters indicating risky playground behaviors they would and would not do. In the intervention group, video and audio presentations were used to expose children to injury occurrences so that injury vulnerability was communicated in a fear-evoking way. In the control group, children only completed the pre- and post-intervention measures. Significant decreases in intentions to risk-take were obtained in the intervention, but not the control group. Effectiveness did not vary with children's age or sex, but was greater for those scoring high in sensation-seeking. A fear-appeals approach proved successful to reduce intended fall-risk behaviors, particularly for children high in sensation-seeking whose risk-taking is motivated by affect arousal.

  9. Playground Safety

    Science.gov (United States)

    ... Prevention Fall Prevention Playground Safety Poisoning Prevention Road Traffic Safety Sports Safety Get Email Updates To receive ... at the Consumer Product Safety Commission’s Playground Safety website . References U.S. Consumer Product Safety Commission. Injuries and ...

  10. Using Playground Maps for Movement

    Science.gov (United States)

    Colvin, A. Vonnie

    2016-01-01

    Many schools now decorate their outside hard surface areas with maps. These maps provide color and excitement to a playground and are a terrific teaching tool for geography. But these maps can easily be integrated into physical education as well to promote both physical activity as well as knowledge of geography. The purpose of this article is to…

  11. Playtesting the Digital Playground

    DEFF Research Database (Denmark)

    Majgaard, G.; Jessen, Carsten

    2009-01-01

    Being able to be absorbed in play in the digital playground is motivating for children who are used digital computer games. The children can play and exercise outdoors while using the same literacy as in indoor digital games. This paper presents a new playground product where an outdoor playgroun...

  12. Developing a playground as catchment area in effort to maintaining groundwater in Jaten village of Karanganyar district of Central Java, Indonesia

    International Nuclear Information System (INIS)

    Legowo, Budi; Darsono; Wahyuningsih, Daru

    2016-01-01

    Changes in land use for housing indirectly disturb the hydrology balance of the area. Groundwater conservation efforts can be done by keeping the function the catchment area. One of the housing developer's obligations is providing open spaces (the playground) to play or activity of the residents. Playground in Bumi Graha Indah Housing, Jaten village, Karanganyar district, Central Java, Indonesia has a fundamental issue, that is, in the rainy season the water is difficult to seep due landfill process are not well planned. It causes the playground become in muddy conditions with tall grass, so that reduces the function as a playground and or activity the residents. In the dry season, the soil dry of landfill caused dust scattering and disrupt the activities of people around the playground. Lack of water resources lead watering process for solving the problem of dust during the dry season was considered ineffective. Structuring drainage combined with modified recharge wells can be used to catch water runoff housing. This modification of water catchment areas can make playground dry quickly after rain so the activities of people are not bothered when utilizing the open space provided. Surface runoff water absorbed in open aquifer so that the hydrological balance always be maintained. Adequacy groundwater in the area playground can be used to sprinkler dust and backup needs clean water residents by creating wells and reservoir stocks. (paper)

  13. Comparative multibody dynamics analysis of falls from playground climbing frames.

    Science.gov (United States)

    Forero Rueda, M A; Gilchrist, M D

    2009-10-30

    This paper shows the utility of multibody dynamics in evaluating changes in injury related parameters of the head and lower limbs of children following falls from playground climbing frames. A particular fall case was used as a starting point to analyze the influence of surface properties, posture of the body at impact, and intermediate collisions against the climbing frame before impacting the ground. Simulations were made using the 6-year-old pedestrian MADYMO rigid body model and scaled head contact characteristics. Energy absorbing surfaces were shown to reduce injury severity parameters by up to 30-80% of those of rigid surfaces, depending on impact posture and surface. Collisions against components of a climbing frame during a fall can increase injury severity of the final impact of the head with the ground by more than 90%. Negligible changes are associated with lower limb injury risks when different surfacing materials are used. Computer reconstructions of actual falls that are intended to quantify the severity of physical injuries rely on accurate knowledge of initial conditions prior to falling, intermediate kinematics of the fall and the orientation of the body when it impacts against the ground. Multibody modelling proved to be a valuable tool to analyze the quality of eyewitness information and analyze the relative injury risk associated with changes in components influencing fall injuries from playground climbing frames. Such simulations can also support forensic investigations by evaluating alternative hypotheses for the sequence of kinematic motion of falls which result in known injuries.

  14. Preventing Playground Injuries and Litigation.

    Science.gov (United States)

    Frost, Joe L.

    1994-01-01

    The typical American playground is antiquated, hazardous, and inappropriate for the developmental needs of children. The paper explains how design, installation, maintenance, and supervision are critical in preventing playground injuries and resulting litigation, noting the importance of regular training for everyone who supervises children on the…

  15. Environmental lead exposure risks associated with children's outdoor playgrounds

    International Nuclear Information System (INIS)

    Taylor, Mark Patrick; Camenzuli, Danielle; Kristensen, Louise Jane; Forbes, Miriam; Zahran, Sammy

    2013-01-01

    This study examines exposure risks associated with lead smelter emissions at children's public playgrounds in Port Pirie, South Australia. Lead and other metal values were measured in air, soil, surface dust and on pre- and post-play hand wipes. Playgrounds closest to the smelter were significantly more lead contaminated compared to those further away (t(27.545) = 3.76; p = .001). Port Pirie post-play hand wipes contained significantly higher lead loadings (maximum hand lead value of 49,432 μg/m 2 ) than pre-play hand wipes (t(27) = 3.57, p = .001). A 1% increase in air lead (μg/m 3 ) was related to a 0.713% increase in lead dust on play surfaces (95% CI, 0.253–1.174), and a 0.612% increase in post-play wipe lead (95% CI, 0.257–0.970). Contaminated dust from smelter emissions is determined as the source and cause of childhood lead poisoning at a rate of approximately one child every third day. -- Highlights: •Spatial and temporal variations in lead exposure due to smelter emissions is examined. •Exposure to lead and other metals is evaluated using pre and post-play hand wipe measures. •The relationship of smelter emissions to surface and hand lead exposures is modelled. •A 1% increase in air lead (μg/m 3 ) was related to a 0.713% increase in lead dust on play surfaces. -- Playgrounds in Port Pirie are seriously contaminated by smelter emissions, with levels of surface dust and hand dust that pose a significant risk of harm to human health

  16. Herbicide and pesticide occurrence in the soils of children's playgrounds in Sarajevo, Bosnia and Herzegovina.

    Science.gov (United States)

    Sapcanin, Aida; Cakal, Mirsada; Imamovic, Belma; Salihovic, Mirsada; Pehlic, Ekrem; Jacimovic, Zeljko; Jancan, Gordan

    2016-08-01

    Pesticide pollution in Sarajevo public playgrounds is an important health and environmental issue, and the lack of information about it is causing concerns amongst the general population as well as researchers. Since children are in direct contact with surface soils on children's playgrounds, such soils should be much more carefully examined. Furthermore, herbicides and pesticides get transmitted from soil surfaces brought from outside the urban areas, or they get dispersed following their direct applications in urban areas. Infants' and children's health can be directly affected by polluted soils because of the inherent toxicity and widespread use of the different pesticides in urban environments such as playgrounds. In addition to that, the presence of chromated copper arsenate (CCA) wood preservative pesticide found as soil pollutant in playing equipment was also documented. Soil samples from playgrounds were collected and analyzed for triazines, carbamates, dithiocarbamates, phenolic herbicides and organochlorine pesticides. Samples for the determination of heavy metals Cu, Cr and As were prepared by microwave-assisted acid digestion, and the findings were determined by using an inductively coupled plasma optical emission spectrometer. Triazines, carbamates, dithiocarbamates, chlorphenoxy compounds, phenolic herbicides, organochlorine pesticides and organotin compounds were detected in playground soils and their determined concentrations (mg/kg) were respectively found as follows: herbicides and pesticides on human health, which strengthens the case for a more preventative and protective approach to the uncontrolled presence of herbicides and pesticides in Sarajevo's playground soils.

  17. Movement Activity Levels on Traditional and Contemporary Playground Structures.

    Science.gov (United States)

    Gabbard, Carl P.; LeBlanc, Elizabeth

    This study investigated playground activity levels of children in grades K-4 and compared levels of use of traditional and creative playground apparatus. The traditional playground area consisted of climbing bars, slides, ladders, chin bars, swings, see saws, and a merry-go-round. The creative playground contained tire hurdles, tire walk, tire…

  18. Enhancing Middle School Science Lessons with Playground Activities: A Study of the Impact of Playground Physics

    Science.gov (United States)

    Friedman, Lawrence B.; Margolin, Jonathan; Swanlund, Andrew; Dhillon, Sonica; Liu, Feng

    2017-01-01

    Playground Physics is a technology-based application and accompanying curriculum designed by New York Hall of Science (NYSCI) to support middle school students' science engagement and learning of force, energy, and motion. The program includes professional development, the Playground Physics app, and a curriculum aligned with New York State…

  19. Assessment of the current status of playground safety in the midwestern region of Turkey: an effort to provide a safe environment for children.

    Science.gov (United States)

    Uskun, Ersin; Kişioğlu, Ahmet Nesimi; Altay, Tülin; Cikinlar, Rengül; Kocakaya, Asuman

    2008-01-01

    This study aimed to identify and evaluate the degree of conformity to the playground standards and the level of compliance with current safety specifications of the playgrounds in the midwestern region of Turkey. An observational technique was used at a total of 57 public playgrounds. A playground safety control form was prepared based on the United States National Program for Playground Safety and the Consumer Product Safety Commission security standards, since there is no national law covering playground equipment and safety in Turkey. The study evaluated the surroundings of the playground, arrangement of equipment in the playground, and characteristics of the equipment. The percentage of playgrounds surveyed with inadequate or hard surfacing was 80.7%. Fifty-two percent of the equipment was found to be inappropriate. Equipment was higher than the recommended heights. The results of our study unfortunately point out that playgrounds for children do not meet many of the safety criteria.

  20. Height, fun and safety in the design of children's playground equipment.

    Science.gov (United States)

    Wakes, Sarah; Beukes, Amanda

    2012-01-01

    The study reported in this paper adopted a holistic design approach to investigate issues associated with height related playground injuries from a users' perspective. The main objective was to gain an understanding of the relationship between height and fun so as to establish practical guidelines for addressing the causes of height related injuries whilst maintaining the attributes of playground equipment that children find fun and challenging. Results show that, on the one hand, the risk of injury increases when height is coupled with the use of upper body strength and, on the other hand, that coordination is a greater source of fun and challenge than height for children. Accordingly, it is suggested that the level of risk of injury attached to children's playground equipment can be reduced when the use of lower body strength and coordination are combined with lower free fall heights.

  1. A Priceless Playground for Exceptional Children.

    Science.gov (United States)

    Adkins, Patricia G.

    Described are 20 pieces of therapeutic playground equipment constructed by volunteers and fathers of children in the Early Learning Center for Exceptional Children (El Paso, Texas). It is noted that discarded and readily available materials (such as old tires) were used, and that no commercial playground equipment was purchased. Information on the…

  2. Child safety in parks' playgrounds (a case study in Tehran’s sub-district parks

    Directory of Open Access Journals (Sweden)

    A.H. Mirlouhi Falavarjani

    2010-10-01

    Full Text Available Background and aimsSafety is a complex concept and multidisciplinary science which is included some difference areas from industrial sectors to urban public arenas. Parks and playgrounds as important public places should be considered in terms of health and safety, especially for kids as prominent social vulnerable citizens. According to CPSC, 147 deaths havebeen reported for under 15 year old child during Jan 1990 to Aug 2000. Every 2.5 minute, kid suffers playground related accident. The main objective in this study is safety assessment ofplaygrounds among the selected parks.MethodsIn this case study, deductive approach and cross-sectional survey was followed, and some parks and playgrounds were selected among five urban counties in Tehran. Our volunteered samples were 160 parents. Playgrounds and related equipment were assessed in terms of safety, as well.ResultsOur findings show that more than 68% of playground equipment might create hazardous condition for kids. Lack of sustain maintenance for both of equipment and playground surface make some risky area for the mentioned group. Statistical analysis by SPSSWin 13 showed that more than 78 % of parents are worry about their child in terms of playground safetyproblems. Safety assessment of swings and slides showed that there are safety based problems in 89% of cases. Due to statistical reports of Tehran Emergency center, 10-12 and 8-10 year old kids suffer play based accident more than others. Reported traumas showed that face and skull and then feet suffered mechanical injury more than other limbs.ConclusionSurely, safety and health considerations are known as Municipality responsibilities, so for safety improvement in parks an integration safety system should be happened. HSE_MS seems a reliable approach for the mention goal. For improvement of exist parks and playground some related standard should be follows such as CPSC standards, EN 1176, and EN 1177. Also anthropometric data development

  3. Special Education Professionals' Perceptions toward Accessible Playgrounds

    Science.gov (United States)

    Stanton-Chapman, Tina L.; Schmidt, Eric L.

    2016-01-01

    The perceptions and beliefs of 303 special education professionals toward currently available playgrounds in their school or community were examined. Survey respondents (a) indicated that their students with a disability could not fully participate in their school or community's playground offerings, (b) discussed the need for a peer buddy program…

  4. Differently Designed Playgrounds and Preschooler's Physical Activity Play

    Science.gov (United States)

    Luchs, Antje; Fikus, Monika

    2018-01-01

    New playground concepts--favouring natural play characteristics--emerge. The aim of our free play study is to explore the relation between newly established natural playgrounds and the widely spread contemporary ones in terms of physical activity levels. The playground features differ in vegetation, topography, size and play equipment. The…

  5. How Can We Provide Safe Playgrounds? = Como podemos proveer lugares con juegos infantiles que no sean peligrosos para los ninos?

    Science.gov (United States)

    ACCESS ERIC, Rockville, MD.

    Outdoor playgrounds can be exciting places where children explore their environment and develop motor and social skills; however, they can also pose serious safety hazards. With the exception of California, no mandatory state or federal standards currently exist regarding manufacture or installation of playground equipment or surfaces. The…

  6. Cause and Prevention of Playground Injuries and Litigation; Case Studies.

    Science.gov (United States)

    Frost, Joe L.; Sweeney, Theodora B.

    This study examined 187 playground injuries and 13 fatalities that resulted in lawsuits between 1981 and 1995, taken from the files of two expert witnesses on playground safety who testified in the cases. The data are presented by geographic location, nature of injuries, cause of injuries/fatalities, playground equipment implicated, location of…

  7. Aldo van Eyck's Playgrounds : Aesthetics, Affordances, and Creativity

    NARCIS (Netherlands)

    Withagen, Rob; Caljouw, Simone R.

    2017-01-01

    After World War II, the Dutch architect Aldo van Eyck developed hundreds of playgrounds in the city of Amsterdam. These public playgrounds were located in parks, squares, and derelict sites, and consisted of minimalistic aesthetic play equipment that was supposed to stimulate the creativity of

  8. Playground Accessibility and Neighbourhood Social Interaction among Parents

    Science.gov (United States)

    Bennet, Scott A.; Yiannakoulias, Nikolaos; Williams, Allison M.; Kitchen, Peter

    2012-01-01

    While the positive association between social interaction and access to green space is well accepted, little research has sought to understand the role of children's playgrounds in facilitating social interaction within a community. Playgrounds are spaces designed to facilitate play and the interaction of children, but may also be important places…

  9. Use and activity levels on newly built bicycle playgrounds

    DEFF Research Database (Denmark)

    Schipperijn, Jasper; Hansen, Christine Kier; Rask, Simon

    2015-01-01

    Increasing the use of urban green space (UGS) as well as increasing cycling could potentially help address the growing inactivity problem. Three bicycle playgrounds were designed based on a participatory process and afterwards constructed in the UGS along a cycle-route on the historic outer defence...... close to one of the sites. A future study involving objective before and after measures when a new bicycle playground is build will be needed to reveal if bicycle playgrounds can provide additional activity to its users, or ‘just’ a different type of activity, in a different location....

  10. School playground facilities as a determinant of children's daily activity

    DEFF Research Database (Denmark)

    Nielsen, Glen; Bugge, Anna; Hermansen, Bianca

    2012-01-01

    This study investigates the influence of school playground facilities on children's daily physical activity.......This study investigates the influence of school playground facilities on children's daily physical activity....

  11. Low-Cost energy contraption design using playground seesaw

    Science.gov (United States)

    Banlawe, I. A. P.; Acosta, N. J. E. L.

    2017-05-01

    The study was conducted at Western Philippines University, San Juan, Aborlan, Palawan. The study used the mechanical motion of playground seesaw as a means to produce electrical energy. The study aimed to design a low-cost prototype energy contraption using playground seesaw using locally available and recycled materials, to measure the voltage, current and power outputs produced at different situations and estimate the cost of the prototype. Using principle of pneumatics, two hand air pumps were employed on the two end sides of the playground seesaw and the mechanical motion of the seesaw up and down produces air that is used to rotate a DC motor to produce electrical energy. This electricity can be utilized for powering basic or low-power appliances. There were two trials of testing, each trial tests the different pressure level of the air tank and tests the opening of on-off valve (Full open and half open) when the compressed air was released. Results showed that all pressure level at full open produced significantly higher voltage, than the half open. However, the mean values of the current and power produced in all pressure level at full and half open have negligible variation. These results signify that the energy contraption using playground seesaw is an alternative viable source of electrical energy in the playgrounds, parks and other places and can be used as an auxiliary or back-up source for electricity.

  12. Exclusionary violence and bullying in the playground: Football and ...

    African Journals Online (AJOL)

    It focuses on these boys who became popularly known as the 'footballing boys', and the kinds of exclusionary violence and bullying they utilise to dominate the playground space and 'police' gender 'transgression'. It explores how some of the 'footballing boys' construct and 'police' gender in the playground through ...

  13. Comparative multibody dynamics analysis of falls from playground climbing frames

    OpenAIRE

    Forero Rueda, Manuel A.; Gilchrist, M. D.

    2009-01-01

    This paper shows the utility of multibody dynamics in evaluating changes in injury related parameters of the head and lower limbs of children following falls from playground climbing frames. A particular fall case was used as a starting point to analyze the influence of surface properties, posture of the body at impact, and intermediate collisions against the climbing frame before impacting the ground. Simulations were made using the 6-year-old pedestrian MADYMO rigid body model and scaled he...

  14. Smokefree signage at children's playgrounds: Field observations and comparison with Google Street View.

    Science.gov (United States)

    Thomson, George; Wilson, Nick

    2017-01-01

    Although there is global growth in outdoor smokefree areas, little is known about the associated smokefree signage. We aimed to study smokefree signage at playgrounds and to compare field observations with images from Google Street View (GSV). We randomly selected playgrounds in 21 contiguous local government areas in the lower North Island of New Zealand, all of which had smokefree playground policies. Field data were collected on smokefree signage along with dog control signage to allow for comparisons. The sensitivity and specificity of using GSV for data collection were calculated. Out of the 63 playgrounds studied, only 44% (95% CI: 33%-57%) had any smokefree signage within 10 m of the playground equipment. The mean number of such signs was 0.8 per playground (range: 0 to 6). Sign size varied greatly from 42 cm 2 up to 2880 cm 2 ; but was typically fairly small (median = 600 cm 2 ; ie, as per a 20 × 30 cm rectangle). Qualitatively the dog signs appeared to use clearer images and were less wordy than the smokefree signs. Most playground equipment (82%), could be seen on GSV, but for these settings the sensitivity for identifying smokefree signs was poor at 16%. Yet specificity was reasonable at 96%. The presence and quality of smokefree signage was poor in this sample of children's playgrounds in this developed country setting. There appears to be value in comparing smokefree signage with other types of signage (eg, dog control signage). Google Street View was not a sensitive tool for studying such signage.

  15. Key issues for the successful design of an intelligent, interactive playground

    NARCIS (Netherlands)

    Sturm, J.A.; Bekker, M.M.; Groenendaal, B.; Wesselink, R.; Eggen, J.H.

    2008-01-01

    An Intelligent Playground is an environment with interactive objects that, using advanced technology such as sensors and actuators, react to the interaction with the children and actively encourage children to play. Thus, an intelligent playground stimulates children to move and play together. In

  16. Research into the Eutrophication of an Artificial Playground Lake near the Yangtze River

    Directory of Open Access Journals (Sweden)

    Min Pang

    2018-03-01

    Full Text Available Water pollution in urban rivers is serious in China. Eutrophication and other issues are prominent. Taking the artificial Playground Lake in Zhenjiang as an example, a numerical model combining particle tracing, hydrodynamics, water quality and eutrophication was constructed to simulate the water quality improvement in Playground Lake with or without water diversion by pump and sluice. Simulation results using particle tracking showed that the water residence time depended on wind direction: east wind, 125 h; southeast wind, 115 h; south wind, 95 h. With no water diversion, the lower the flow velocity of Playground Lake under three wind fields, the more serious the eutrophication. Under pump diversion, the water body in Playground Lake can be entirely replaced by water diversion for 30 h. When the temperature is lower than 15 °C, from 15 °C to 25 °C and higher than 25 °C, the water quality can be maintained for 15 d, 10 d and 7 d, respectively. During high tide periods of spring tides in the Yangtze River from June to August, the water can be diverted into the lake through sluices. The greater the Δh (the water head between the Yangtze River and Playground Lake, the more the water quality will improve. Overall, the good-to-bad order of water quality improvements for Playground Lake is as follows: pumping 30 h > sluice diversion > no water diversion. This article is relevant for the environmental management of the artificial Playground Lake, and similar lakes elsewhere.

  17. Once bitten, twice shy? Medically-attended injuries can sensitise parents to children's risk of injuries on playgrounds.

    Science.gov (United States)

    Morrongiello, B A; Howard, A W; Rothman, L; Sandomierski, M

    2009-02-01

    To compare risk perceptions of parents whose child sustained a medically attended playground injury (cases) with those of parents whose child had not (controls) to address two questions. Does having a child experience a medically attended injury: (1) sensitise parents to children's injury vulnerability and severity; (2) influence parents' appraisal of the injury mechanism (child's behaviour), attributions for injuries or beliefs about strategies for prevention? Each case-control parent dyad was assigned to one of two conditions: (1) being presented with 10 common injury-risk playground behaviours specific to the equipment on which their child had been hurt, and asked to appraise injury vulnerability and severity; or (2) being presented with scenarios about playground injuries that varied in severity but were all based on the same child behaviour, and asked questions about this behaviour, attributions for injury and strategies for prevention. The results support the occurrence of a sensitisation process. Compared with control parents, case parents showed higher ratings of injury severity and children's vulnerability to injury, made fewer attributions for injuries to bad luck, and endorsed a greater diversity of prevention strategies, including parent (closer supervision), child (teaching rules about safe play on playgrounds) and environmental (modifications to playgrounds). A child's medically attended injury can create a "teachable moment" for the parent. Linking injury-prevention programming to this teachable moment may increase the likelihood of evoking changes in parental supervisory behaviour and their setting of rules limiting their child's risk behaviours to reduce the occurrence of childhood injury.

  18. The value of (pre)school playgrounds for children's physical activity level: a systematic review.

    Science.gov (United States)

    Broekhuizen, Karen; Scholten, Anne-Marie; de Vries, Sanne I

    2014-05-03

    The (pre)school environment is an important setting to improve children's health. Especially, the (pre)school playground provides a major opportunity to intervene. This review presents an overview of the existing evidence on the value of both school and preschool playgrounds on children's health in terms of physical activity, cognitive and social outcomes. In addition, we aimed to identify which playground characteristics are the strongest correlates of beneficial effects and for which subgroups of children effects are most distinct. In total, 13 experimental and 17 observational studies have been summarized of which 10 (77%) and 16 (94%) demonstrated moderate to high methodological quality, respectively. Nearly all experimental studies (n = 11) evaluated intervention effects on time spent in different levels of physical activity during recess. Research on the effects of (pre)school playgrounds on cognitive and social outcomes is scarce (n = 2). The experimental studies generated moderate evidence for an effect of the provision of play equipment, inconclusive evidence for an effect of the use of playground markings, allocating play space and for multi-component interventions, and no evidence for an effect of decreasing playground density, the promotion of physical activity by staff and increasing recess duration on children's health. In line with this, observational studies showed positive associations between play equipment and children's physical activity level. In contrast to experimental studies, significant associations were also found between children's physical activity and a decreased playground density and increased recess duration. To confirm the findings of this review, researchers are advised to conduct more experimental studies with a randomized controlled design and to incorporate the assessment of implementation strategies and process evaluations to reveal which intervention strategies and playground characteristics are most effective.

  19. Methodological framework for the ergonomic design of children's playground equipment: a Serbian experience.

    Science.gov (United States)

    Grozdanovic, Miroljub; Jekic, Savko; Stojiljkovic, Evica

    2014-01-01

    Adequate application of the static and dynamic anthropometric measures of pre-school children in ergonometric design of children's playground equipment should eliminate all dangers and difficulties in their use. Possibilities of injuries, insecure movements, discomfort able positions and some other dangerous actions may be minimized; and safety and health protection of pre-school children will be increased. Children's playground represents a significant space of activity for pre-school children. Therefore, it is necessary to apply ergonomic principles which contribute to the adjustment of the playground elements to children's anatomic features. Based on the results presented in this paper, new constructions were designed and new playgrounds were installed in Serbia. Participants were children from three pre-school age groups: Junior age group (3-4 years of age, 17 children), Medium age group (4-5 years of age, 22 children), and Senior age group (5-6 years of age, 26 children). Thirty-one static anthropometric measures (12 in standing position, 11 in sitting position, 7 related to dimensions of hand, foot an head, with body weight and shoe size) and 15 dynamic anthropometric measures (7 in standing position, 6 in sitting position and 2 dimension of foot and hand) were defined for the study. Measurements were taken using an anthrop-meter, a flexible measuring tape. Equations for ergonomic design of children's playground elements were also defined. Basic statistical data of static and dynamic anthropometric measurements of the pre-school children are presented in this paper, as well as the statistical calculation of the corrective anthropometric measurements. Measurements were performed in "Poletarac" kindergarten, part of the pre-school institution "Radost" in Cacak. Elements of playground equipment in "Bambi" kindergarten in Kragujevac (the Indian tent "wigwam", gate-house, swing and carousel) were designed and built using these parameters. Based on the obtained

  20. Model playground for autistic children

    DEFF Research Database (Denmark)

    Castro, Thais; Castro, Alberto; Lima, David

    2017-01-01

    Children with autism often have difficulties in learning the social skills and norms of peer social interaction, which severely affect and limit their social lives. Aiming at addressing this issue, through design, we developed a digital-analogue model playground to help them understand and cope...... of social skills and norms through peer learning activities amongst children with autism....

  1. Participation of a preschooler with visual impairments on the playground: effects of musical adaptations and staff development.

    Science.gov (United States)

    Kern, P; Wolery PhD, M

    2001-01-01

    The purpose of this study was to evaluate the adaptations of a playground, and subsequently staff development, on the participation of a 3-year-old boy with congenital blindness. A single-subject design with three conditions (baseline, adaptations of the playground, and staff development) was used. The playground adaptation involved adding musical stations in strategic locations on the playground and connecting them with a "path" that provided auditory feedback. The staff training involved the music therapist providing individualized instruction to the staff who supervised the child. The child's participation was measured in terms of social interaction with peers or adults, play and engagement with materials, movement on the playground, and stereotypic behaviors. The playground adaptation resulted in no changes in the child's social interactions with peers or adults, increases in engagement, no change in movement on the playground, and a decrease in stereotypic responses. Staff training resulted in increased but variable interactions with adults and peers, in additional increases in engagement, less movement, and similar levels of stereotypic behavior. The findings suggest that musical adaptations of physical environments may he helpful but not sufficient for promoting desired outcomes.

  2. Analysis of Playground Injuries and Litigation.

    Science.gov (United States)

    Frost, Joe L.

    A study analyzed 82 cases of playground injuries and litigation (including 7 fatalities) in 28 states. In order of frequency, injuries happened in public schools, public parks, child care centers, apartment complexes, fast food restaurants, backyards, recreation camps, state parks, and state schools. Sixty-five percent of all injuries resulted…

  3. No “Obstacles” In Playgrounds That Are Not Only Accessible But Also Inclusive

    Directory of Open Access Journals (Sweden)

    Hatice Ayataç

    2016-12-01

    Full Text Available In the current century, the importance of play for children is a major issue addressed in the literature. Play enables the physical, mental and social development of children. According to the United Nations Convention on the Rights of the Child, engaging in play is a fundamental right for children. This article of the convention covers all children below the age of 18 and does not exclude the children with disabilities. Like their peers, children with disabilities should also enjoy the right to engage in play, and societies should use every means available in order to help children play whether indoors or outdoors.According to the 2011 Population and Housing Research, 6.6% of the population in Turkey has one or more disabilities. The target group of this study is ‘children with disabilities’ who live in İstanbul. In this group, speech disorders (21.9%, and mental disabilities (17.1% prove to be the most dominant disabilities. However, the number of playgrounds where disabled children can play are scarce in number.This study provides an analysis of children’s playgrounds, which are essential for the development of children, and evaluates the design features of these playgrounds based on inclusive design principles. The study also addresses the requirements of inclusive playgrounds by referring to the examples of inclusive playgrounds around the world as well as those few examples in Turkey.  The design principles of inclusive playgrounds were also evaluated for three parks in İstanbul which were designed and are currently in use - namely Kadıköy Göztepe 60. Yıl Park, Beşiktaş Dilek Sabancı Park and Kadıköy Selamiçeşme Özgürlük Park.

  4. The value of (pre)school playgrounds for children's physical activity level: A systematic review

    NARCIS (Netherlands)

    Broekhuizen, K.; Scholten, A.M.; Vries, S.I. de

    2014-01-01

    The (pre)school environment is an important setting to improve children's health. Especially, the (pre)school playground provides a major opportunity to intervene. This review presents an overview of the existing evidence on the value of both school and preschool playgrounds on children's health in

  5. The Children’s Playground in the Context of Cultural-Historical Psychology

    Directory of Open Access Journals (Sweden)

    Smirnova E.O.,

    2016-12-01

    Full Text Available The article describes the possible application of the principles of cultural-historical approach and activity theory to the inspection of toys and play environments. A children’s playground is treated as cultural means or artifact created by adults for starting a child’s activity. In terms of cultural and historical psychology, psycho-pedagogical analysis of a playground is based on the identification of the play value level and the compliance with the objectives peculiar to the age. Analysis and design are based on the understanding of the playground as a single space, where each element has the potential for any children’s development activity — games, communication, experimentation, etc. The following criteria of psychological and pedagogical inspection are identified and well-grounded: the principle of orientation to age-related peculiarities, the principle of high play value, the principle of transparency of objects, the principle of supporting acceptable risk, the principle of taking account of visitors’ activity levels, invitation to dialogue — the principle of dialogueness. The use of these principles in the course of designing playgrounds is illustrated by examples. These show that the conceptual apparatus of cultural and historical psychology may be used not only to explain the mechanisms and forms of mental development, but also for the analysis of particular conditions of a child’s mental development and design of play environments.

  6. The value of (pre)school playgrounds for children’s physical activity level : a systematic review

    NARCIS (Netherlands)

    S.I. (Sanne) de Vries; Karen Broekhuizen; Anne-Marie Scholten

    2014-01-01

    The (pre)school environment is an important setting to improve children’s health. Especially, the (pre)school playground provides a major opportunity to intervene. This review presents an overview of the existing evidence on the value of both school and preschool playgrounds on children’s health in

  7. Informal Nature Experience on the School Playground

    Science.gov (United States)

    Raith, Andreas

    2015-01-01

    In Germany, all-day care and all-day schooling are currently increasing on a large-scale. The extended time children spend in educational institutions could potentially result in limited access to nature experience for children. On the other hand, it could equally create opportunities for informal nature experience if school playgrounds have a…

  8. Aldo van Eyck’s Playgrounds: Aesthetics, Affordances, and Creativity

    Directory of Open Access Journals (Sweden)

    Rob Withagen

    2017-07-01

    Full Text Available After World War II, the Dutch architect Aldo van Eyck developed hundreds of playgrounds in the city of Amsterdam. These public playgrounds were located in parks, squares, and derelict sites, and consisted of minimalistic aesthetic play equipment that was supposed to stimulate the creativity of children. Over the last decades, these playgrounds have been studied by sociologists, theorists of art and architecture, and psychologists. Adopting an ecological approach to the human environment, it is argued that the abstract forms of van Eyck’s play sculptures indeed stimulate the creativity of the child. Whereas a slide or a swing almost dictates what a child is supposed to do, van Eyck’s play equipment invites the child to actively explore the numerous affordances (action possibilities it provided. However, it is argued that the standardization (e.g., equal distances between blocks or bars that tends to characterize van Eyck’ play equipment has negative effects on the playability. This standardization, which was arguably the result of the aesthetic motives of the designer, might be appealing to children when simply looking at the equipment, but it is not of overriding importance to them when playing in it. Indeed, a recent study indicates that the affordances provided by messy structures appear to have a greater appeal to playing children.

  9. Soil intervention as a strategy for lead exposure prevention: The New Orleans lead-safe childcare playground project

    Energy Technology Data Exchange (ETDEWEB)

    Mielke, Howard W., E-mail: howard.mielke@gmail.com [Department of Chemistry, Tulane University, New Orleans, LA 70118 (United States); Center for Bioenvironmental Research at Tulane and Xavier Universities, 1430 Tulane Avenue SL-3, New Orleans, LA 70112 (United States); Covington, Tina P. [Charity School of Nursing, Delgado Community College, New Orleans, LA 70112-1397 (United States); College of Nursing, University of South Alabama, Doctor of Nursing Practice Program (student), Mobile AL 36688-0002 (United States); Mielke, Paul W. [Department of Statistics, Colorado State University, Fort Collins, CO 80523-1877 (United States); Wolman, Fredericka J. [Director of Pediatrics, Department of Children and Families, State of Connecticut, Hartford, CT 06473 (United States); Powell, Eric T.; Gonzales, Chris R. [Lead Lab, Inc., New Orleans, LA 70179-1125 (United States)

    2011-08-15

    The feasibility of reducing children's exposure to lead (Pb) polluted soil in New Orleans is tested. Childcare centers (median = 48 children) are often located in former residences. The extent of soil Pb was determined by selecting centers in both the core and outlying areas. The initial 558 mg/kg median soil Pb (range 14-3692 mg/kg) decreased to median 4.1 mg/kg (range 2.2-26.1 mg/kg) after intervention with geotextile covered by 15 cm of river alluvium. Pb loading decreased from a median of 4887 {mu}g/m{sup 2} (454 {mu}g/ft{sup 2}) range 603-56650 {mu}g/m{sup 2} (56-5263 {mu}g/ft{sup 2}) to a median of 398 {mu}g/m{sup 2} (37 {mu}g/ft{sup 2}) range 86-980 {mu}g/m{sup 2} (8-91 {mu}g/ft{sup 2}). Multi-Response Permutation Procedures indicate similar (P-values = 0.160-0.231) soil Pb at childcare centers compared to soil Pb of nearby residential communities. At {approx}$100 per child, soil Pb and surface loading were reduced within hours, advancing an upstream intervention conceptualization about Pb exposure prevention. - Highlights: > Upstream thinking refers to attending to causative agents that affect outcomes. > New Orleans has a high density soil Pb map of all residential communities. > Many childcare centers are located in Pb polluted residential communities. > Evaluation of childcare center playground soils substantiated severe Pb pollution. > Pursuing upstream thinking, low Pb soil was put on playgrounds to protect children. - Within hours, at a cost of about U.S. $100 (2010) per child, it is feasible to transform exterior play areas at childcare centers from Pb contaminated to Pb-safe with a large margin of safety.

  10. An Evaluation of Photographic Activity Schedules to Increase Independent Playground Skills in Young Children with Autism

    Science.gov (United States)

    Akers, Jessica S.; Higbee, Thomas S.; Pollard, Joy S.; Pellegrino, Azure J.; Gerencser, Kristina R.

    2016-01-01

    We used photographic activity schedules to increase the number of play activities completed by children with autism during unstructured time on the playground. All 3 participants engaged in more playground activities during and after training, and they continued to complete activities when novel photographs were introduced.

  11. School Playground Facilities as a Determinant of Children's Daily Activity: A Cross-Sectional Study of Danish Primary School Children

    DEFF Research Database (Denmark)

    Nielsen, Glen; Bugge, Anna; El-Naaman, Bianca

    2012-01-01

    This study investigates the influence of school playground facilities on children's daily physical activity.......This study investigates the influence of school playground facilities on children's daily physical activity....

  12. Playground Equipment Guide: For Teachers, Park and Recreation Directors, Parents, Youth Leaders, and Other Concerned Adults.

    Science.gov (United States)

    Consumer Product Safety Commission, Washington, DC.

    This guide was designed to assist parents, teachers, youth leaders, and park and recreation directors in the safe selection, use, installation, maintenance and repair of playground equipment. The nature and necessity of children's play are discussed briefly and information is presented on four main types of playground equipment: (1) swings, (2)…

  13. School playgrounds, laboratories for the social construction of hegemonic masculinity

    Directory of Open Access Journals (Sweden)

    Beatriz Garay IBÁÑEZ DE ELEJALDE

    2017-12-01

    Full Text Available The study of the use of playgrounds by the football is not something new today. But the normality with which this practice is assumed is the key driver in the construction of hegemonic masculinity and gender biases for non-intervention by the school. A case study was conducted in the city of Vitoria, to know what is the meaning that members of the school community give this situation, through questionnaires and focus groups with families, teachers and students. We check the persistence of imbalances in the dynamics of school breaks and biologists justifications for non-intervention by a sector of teachers. We propose a seductive intervention in these spaces, and a greater formative reflection of the teachers in the elaboration of specific programs for the dynamics of the playgrounds.

  14. Children's Playgrounds and Everyday City Life of Childhood

    Science.gov (United States)

    Filipova, Alexandra Gennadyevna; Syroed, Nadezhda Savvovna; Goncharova, Svetlana Vladimirovna

    2016-01-01

    Play areas of entertainment and development are new recourses for modern city children, but at the same time, they produce risks of road traffic accidents, deviation, social inequality and social exclusion. Playgrounds in city/town yards are free zones of children's pastime, where children communicate and play together. The aim of this article is…

  15. Using interviews and peer pairs to better understand how school environments affect young children's playground physical activity levels: a qualitative study.

    Science.gov (United States)

    Parrish, Anne-Maree; Yeatman, Heather; Iverson, Don; Russell, Ken

    2012-04-01

    School break times provide a daily opportunity for children to be active; however, research indicates this time is underutilized. Reasons for low children's playground activity levels have primarily focused on physical barriers. This research aimed to contribute to physical environmental findings affecting children's playground physical activity levels by identifying additional variables through the interview process. Thirteen public schools were included in the sample (total 2946 children). Physical activity and environmental data were collected over 3 days. Environmental variables were manually assessed at each of the 13 schools. Observational data were used to determine which three schools were the most and least active. The principal, three teachers and 20 students in Grades 4-6 from these six schools (four lower and two average socioeconomic status) were invited to participate in the interview process. Student interviews involved the paired interview technique. The main themes generated from the school interviews included the effect of non-fixed equipment (including balls), playground markings, playground aesthetics, activity preference, clothing, the amount of break time available for play, teacher playground involvement, gender, bullying, school policies, student confidence in break-time activity and fundamental movement skills. The effect of bullying on playground physical activity levels was concerning.

  16. Load Absorption Characteristics of Tyre Production Waste Rubber for Playground Floor Systems

    Directory of Open Access Journals (Sweden)

    Abdul Ghani A.N.

    2014-01-01

    Full Text Available The floor surfaces where slides and swings are placed in parks and playrooms should be soft and thick to ensure that whenever a child falls, the surface can withstand the impact and minimize injuries to the child. Shredded tyres from waste tyres or waste rubber from tyre manufacturing could become beneficial as shock absorber material which can be used as a playground floor. In this study, rubber cubes and rubber pads with 5%, 8% and 10% SBR mixes were prepared for mechanical testing. Two types of floor design surfaces with and without plywood on the surface were assembled for the shock test. Gmax and HIC of this waste rubber flooring system were investigated using the compression test for the rubber cube and the drop test for the rubber pad. The criteria of general protection standards are 200g for optimum acceleration and 1000 for HIC. The Gmax and HIC results indicated that the material and system could ensure a safe fall from up to 1.0m height.

  17. Social Competence at the Playground: Preschoolers during Recess

    Science.gov (United States)

    Veiga, Guida; de Leng, Wendy; Cachucho, Ricardo; Ketelaar, Lizet; Kok, Joost N.; Knobbe, Arno; Neto, Carlos; Rieffe, Carolien

    2017-01-01

    Social interactions at the playground have been represented as a rich learning opportunity to hone and master social skills at preschool years. Specifically, all forms of social play (fantasy, role, exercise or rough-and-tumble) have been related to children's social competence. The main goal of this study was to examine whether it is a certain…

  18. Il Playground come laboratorio di creatività e inclusione

    Directory of Open Access Journals (Sweden)

    Antonio Lauria

    2015-09-01

    Full Text Available In general, play areas are highly standardised place that include a set of standardised equipments alien to the reference context, poor in stimuli and incapable of triggering fruitful social relationships. Playing activities are often repetitive, boring and mechanical, contributing in a somewhat limited extent (and ever counterproductive to the development of the child and nurturing a passive and poor approach to play. Adequate play facilities for disabled children are not common. This article highlights the strategic role of the play for the well-being of children and analyses playground in ethical, social and architectural terms. It claims that playgrounds should be genuine ‘work of architecture’ well-grounded within the reference socio-cultural, environmental and architectural context and in ‘dialogue’ with nature. They should be able to encourage encounters and mutual enrichment between children that come from different walks of life through solutions able to fun, ease tensions and stimulate creativity, expression and self-knowledge.

  19. Science Understanding through Playground Physics: Organized Recess Teaching (SUPPORT)

    Science.gov (United States)

    Kincaid, Russell

    2010-03-01

    From 1995-2007, U.S. science students in grade four scored higher than the scaled TIMSS average, but their scores did not improve over this time. Moreover, in the area of physical science, the U.S. scored significantly lower than several Asian countries, as well as Russia, England, and Latvia (TIMSS). Methods to enhance student achievement in science are still being sought. An approach to utilizing playground equipment as a teaching tool for a variety of physics concepts was developed as a physical science teaching method. This program established an appropriate set of experiments, coordinated the effort with local school districts, and implemented a brief pilot study to test the teaching methodology. The program assigned undergraduate middle school science education majors to teach small groups of fourth grade students. The experimental group used the newly developed ``Playground Physics'' methodology while the control group used traditional approaches. Follow up activities will include an expansion of the duration and the scope of the program.

  20. Effect of major school playground reconstruction on physical activity and sedentary behaviour: Camden active spaces

    Directory of Open Access Journals (Sweden)

    Mark Hamer

    2017-06-01

    Full Text Available Abstract Background The physical school environment is a promising setting to increase children’s physical activity although robust evidence is sparse. We examined the effects of major playground reconstruction on physical activity and sedentary time in primary schools using a quasi-experimental design (comparison group pre-test/post-test design. Methods Five experimental and two control schools from deprived areas of inner city London were recruited at baseline. Main outcome was physical activity and sedentary time measured from objective monitoring (Actigraph accelerometer at one year follow up. Pupils’ impressions of the new playground were qualitatively assessed post construction. Results A total of 347 pupils (mean age = 8 years, 55% boys; 36% Caucasian were recruited into the study at baseline; 303 provided valid baseline Actigraph data. Of those, 231 (76% completed follow-up (n = 169 intervention; n = 62 control and 77.4% of the sample recorded at least 4 days of Actigraph wear. In mixed models adjusted for age, sex, ethnicity, ratio activity or sedentary/wear time at baseline, wear time at follow up, and school, no differences were observed in total moderate – vigorous activity (B = −1.4, 95% CI, −7.1, 4.2 min/d, light activity (B = 4.1, 95% CI, −17.9, 26.1, or sedentary time (B = −3.8, 95% CI, −29.2, 21.6 min/d between groups. There were significant age interactions for sedentary (p = 0.002 and light intensity physical activity (p = 0.008. We observed significant reductions in total sedentary (−28.0, 95% CI, −1.9, −54.1 min/d, p = 0.037 and increases in total light intensity activity (24.6, 95% CI, 0.3, 48.9 min/d, p = 0.047 for children aged under 9 yrs. old in the intervention. Conclusion Major playground reconstruction had limited effects on physical activity, but reduced sedentary time was observed in younger children. Qualitative data suggested that the children enjoyed the new

  1. The Playground Game: Inquiry‐Based Learning About Research Methods and Statistics

    NARCIS (Netherlands)

    Westera, Wim; Slootmaker, Aad; Kurvers, Hub

    2014-01-01

    The Playground Game is a web-based game that was developed for teaching research methods and statistics to nursing and social sciences students in higher education and vocational training. The complexity and abstract nature of research methods and statistics poses many challenges for students. The

  2. Active Play: Exploring the Influences on Children's School Playground Activities

    Science.gov (United States)

    Hyndman, Brendon; Benson, Amanda; Telford, Amanda

    2016-01-01

    Because children spend so much of their time in schools, their playgrounds offer a good setting for promoting active play in young lives. Teachers, instead of considering active play a taxing demand on their busy day, have begun to develop an informal curriculum for it. The authors review the research on children's active play and explores its…

  3. Creative and Playful Learning on Technology-Enriched Playgrounds: An International Investigation

    Science.gov (United States)

    Randolph, Justus J.; Kangas, Marjaana; Ruokamo, Heli; Hyvönen, Pirkko

    2016-01-01

    The purpose of this quasi-experimental study was to determine the degree that creative and playful learning (CPL) in a technology-enriched playground influences academic achievement of students and what factors are responsible for successes. The participants were 276 students from 12 elementary classrooms in the Netherlands and Finland. The…

  4. The Playground in the Classroom - Fractions and Robot Technology

    DEFF Research Database (Denmark)

    Majgaard, Gunver

    2009-01-01

    What happens when the digital playground is brought into the class room and is it possible to transform it into a valuable educational tool? The paper describes the changing process from climbing rack to indoor educational tool. The climbing rack became a math tool and in the area of fraction...

  5. Children’s Caregivers and Public Playgrounds: Potential Reservoirs of Infection of Hand-foot-and-mouth Disease

    Science.gov (United States)

    Li, Pengyuan; Li, Tao; Gu, Qiuyun; Chen, Xiaomin; Li, Jiahui; Chen, Xiashi; Chen, Yan; Zhang, Danwei; Gao, Rong; He, Zhenjian; Zhu, Xun; Zhang, Wangjian; Hao, Yuantao; Zhang, Dingmei

    2016-11-01

    Hand-foot-and-mouth disease (HFMD) is a common infectious disease, which has led to millions of clinical cases and hundreds of deaths every year in China. This study aimed to exploring the effects on HFMD transmission of children’s caregivers and public area, as well as trying to locate the potential reservoirs of infections in primary cases. Total children’s 257 samples (98 children’s caregivers and 159 environmental samples) were tested for the presence of universal enterovirus, enterovirus 71, coxsackie virus A6 and A16 by real-time fluorescence quantitative polymerase chain reaction (qPCR). 5.84% (15/257, 95% confidence interval [CI]: 2.98%, 8.70%) of total samples had positive results of enterovirus. The enterovirus positive rates of children’s caregiver samples and environmental samples were respectively 7.14% (7/98, 95% CI: 2.04%, 12.24%), and 5.03% (8/159, 95% CI: 1.63%, 8.43%); 7.61% (7/92, 95% CI: 2.21%, 13.01%) of wiping samples from playgrounds and 1.49% (1/67, 95% CI: 0, 7.00%) of air samples in indoor market places had positive result of enterovirus. High positive rates of enterovirus in children’s caregivers and from playgrounds indicated that they would be potential reservoirs of HFMD infection, as children might be infected via contacting with asymptomatic-infected individuals or exposure of contaminated surface of public facilities.

  6. Soil pollution fingerprints of children playgrounds in Sarajevo city, Bosnia and Herzegovina.

    Science.gov (United States)

    Sapcanin, Aida; Cakal, Mirsada; Jacimovic, Zeljko; Pehlic, Ekrem; Jancan, Gordan

    2017-04-01

    This is the first study, 10 years after the war activities, to report about the content of heavy metals and metalloids, polycyclic aromatic hydrocarbons (PAHs), and polychlorinated biphenyls (PCBs) found in samples of soils from selected playgrounds in Sarajevo. Due to the fact that children are in direct contact with surface soils, it has been recommended that children's playgrounds should be given special consideration in this respect. Basic properties (pH in H 2 O, pH in 1 mol dm -3 KCl, humus, and CaCO 3 ) of the examined soils were determined. Samples for the determination of heavy metals and metalloids were prepared by microwave-assisted acid digestion and determined by using an inductively coupled plasma optical emission spectrometer. Fluorine was determined potentiometrically. Gas chromatography with mass spectrometry was used for determination of PAHs and PCBs. Determined contents (mg kg -1 ) for Cd, Pb, Hg, Cr, Ni, Cu, Zn, Co, Mo, Fe, Se, As, B, and F were in the ranges from: 0.031 ± 0.03 to 0.52 ± 0.05; 26.1 ± 2.5 to 47.7 ± 4.5; 0.07 ± 0.01 to 0.50 ± 0.08; 26.2 to 50; 19.5 ± 1.6 to 33.3 ± 2.7; 12.8 ± 1.8 to 31.9 ± 4.5; 56.0 ± 4.0 to 89.0 ± 6.5; 6.7 ± 0.6 to10.6 ± 1.0; soils, and may be included in projects planning children's health risk assessments and adopting environmental legislation which has not been sufficiently regulated in Bosnia and Herzegovina so far.

  7. Feasibility and safety of a novel in vivo model to assess playground falls in children.

    Science.gov (United States)

    Ehrlich, Peter F; Young, Justin G; Ulin, Sheryl; Wooley, Charles; Armstrong, Thomas J; Buschmann, Bethany; Galecki, Andrzej; Ashton-Miller, James A

    2013-07-01

    Falls are the leading cause of nonfatal unintentional injuries among hospitalized children with playground equipment accounting for more than 50%. National standards for playground rung and rail design exist, but there a lack of in vivo models available to test these standards. We developed a novel in vivo model to test rung and rail design. We report the feasibility and safety of the model. A device was built to simulate children hanging onto a playground bar until their hand slips off. This was defined as breakaway strength. The handle unit was mounted on a vertical cable that was mechanically raised and lowered using a linear actuator controlled by the experimenter. The unit was padded and contained a video camera that recorded the posture of the hand during each trial. Breakaway force and torque were recorded as they held onto the handle by LabView software. In addition, standard anthropometrics and grip strength were recorded. Biomedical engineering approved the device. There were 425 eligible students aged 5 years to 11 years. Of these, 93% (397) participated (212 males and 185 females). Ninety-nine percent (396 of 397) completed all three experimental stations, one declined because of fear. There were no injuries and no falls. Average time to complete the study was 22 ± 0.5 minutes. Ninety-one percent of participants were right handed; the ethnicity was representative of the local area with 79% being white. Mean ± SD height, weight, and body mass index for the 397 participants were 1.28 ± 0.11 m, 28.0 ± 8.12 kg, and 16.31 ± 2.59 kg/m², respectively. Hand size, grip strength, and maximum breakaway force increased with age. This model is safe and feasible and maybe a viable method to assess rung and rail design for playgrounds.

  8. PLAYGROUND: preparing students for the cyber battleground

    Science.gov (United States)

    Nielson, Seth James

    2016-12-01

    Attempting to educate practitioners of computer security can be difficult if for no other reason than the breadth of knowledge required today. The security profession includes widely diverse subfields including cryptography, network architectures, programming, programming languages, design, coding practices, software testing, pattern recognition, economic analysis, and even human psychology. While an individual may choose to specialize in one of these more narrow elements, there is a pressing need for practitioners that have a solid understanding of the unifying principles of the whole. We created the Playground network simulation tool and used it in the instruction of a network security course to graduate students. This tool was created for three specific purposes. First, it provides simulation sufficiently powerful to permit rigorous study of desired principles while simultaneously reducing or eliminating unnecessary and distracting complexities. Second, it permitted the students to rapidly prototype a suite of security protocols and mechanisms. Finally, with equal rapidity, the students were able to develop attacks against the protocols that they themselves had created. Based on our own observations and student reviews, we believe that these three features combine to create a powerful pedagogical tool that provides students with a significant amount of breadth and intense emotional connection to computer security in a single semester.

  9. Developing games with Magic Playground: a gesture-based game engine

    OpenAIRE

    Dehanov, Juana; Dias, José Miguel Salles; Bastos, Rafael; Cabral, Carolina

    2005-01-01

    ACE 134 This paper presents Magic Playground, a game engine that enables the development of entertainment applications with realtime gesture-based Human-Computer Interaction (HCI). We describe the main architectural elements of our system and provide a guideline on how to program the engine in order to create games. Finally, we present usability evaluation results of a game, which emulates the known Tetris game1.

  10. Automatic behavior analysis in tag games: From traditional spaces to interactive playgrounds

    NARCIS (Netherlands)

    Moreno, Alejandro; Poppe, R.W.

    2016-01-01

    Tag is a popular children’s playground game. It revolves around taggers that chase and then tag runners, upon which their roles switch. There are many variations of the game that aim to keep children engaged by presenting them with challenges and different types of gameplay. We argue that the

  11. A Parent's Guide to Playground Safety, [and] The Multiage Classroom: A Guide for Parents, [and] Multiple Intelligences: Different Ways of Learning. ACEI Speaks Series.

    Science.gov (United States)

    Frost, Joe L.; And Others

    Three brochures for parents are presented. The first lists potential playground hazards and suggestions for improving playgrounds. The second describes benefits of the multiage classroom, comparing such a classroom with a traditional, single-grade class. The third brochure describes verbal, logical, visual, musical, and physical learning styles…

  12. We're Playing "Jeremy Kyle"! Television Talk Shows in the Playground

    Science.gov (United States)

    Marsh, Jackie; Bishop, Julia

    2014-01-01

    This paper focuses on an episode of play in a primary school playground in England, which featured a group of children re-enacting elements of the television talk show "The Jeremy Kyle Show". The episode is analysed in the light of work that has identified the key elements of the talk show genre and the children's play is examined in…

  13. Blow Bits : Creative playgrounds, gamification and virtuosity with hybrid design tools and environments (HDTE)

    NARCIS (Netherlands)

    Wendrich, Robert E.

    2017-01-01

    Playgrounds (real or virtual) are universal areas where most people learn to play, interact, engage, immerse to unlearn and relearn repeatedly in order to get more fundamental understanding and insights on their creativity, communication and collaboration patterns with others. Consequently, finding

  14. Effectiveness and feasibility of lowering playground density during recess to promote physical activity and decrease sedentary time at primary school.

    Science.gov (United States)

    D'Haese, Sara; Van Dyck, Delfien; De Bourdeaudhuij, Ilse; Cardon, Greet

    2013-12-10

    This pilot study aimed at investigating the effectiveness of lowering playground density on increasing children's physical activity and decreasing sedentary time. Also the feasibility of this intervention was tested. Data were collected in September and October 2012 in three Belgian schools in 187, 9-12 year old children. During the intervention, playground density was decreased by splitting up recesses and decreasing the number of children sharing the playground. A within-subject design was used. Children wore accelerometers during the study week. Three-level (class - participant - measurement (baseline or intervention)) linear regression models were used to determine intervention effects. After the intervention week the school principals filled out a questionnaire concerning the feasibility of the intervention. The available play space was 12.18 ± 4.19 m²/child at baseline and increased to 24.24 ± 8.51 m²/child during intervention. During the intervention sedentary time decreased (-0.58 min/recess; -3.21%/recess) and moderate-to-vigorous physical activity (+1.04 min/recess; +5.9%/recess) increased during recess and during the entire school day (sedentary time: -3.29%/school day; moderate-to-vigorous physical activity +1.16%/school day). All principals agreed that children enjoyed the intervention; but some difficulties were reported. Lowering playground density can be an effective intervention for decreasing children's sedentary time and increasing their physical activity levels during recess; especially in least active children.

  15. Family Smoking Prevention And Tobacco Control Act: banning outdoor tobacco advertising near schools and playgrounds.

    Science.gov (United States)

    Luke, Douglas A; Ribisl, Kurt M; Smith, Carson; Sorg, Amy A

    2011-03-01

    The tobacco industry has challenged new FDA rules restricting outdoor tobacco advertising near schools and playgrounds on First Amendment grounds, arguing that they would lead to a near complete ban on tobacco advertising in dense urban areas. To examine how the 2009 Family Smoking Prevention and Tobacco Control Act (FSPTCA) rules banning outdoor tobacco advertising near schools and playgrounds would affect tobacco retailers. GIS spatial analyses of two different states (Missouri, New York), along with more detailed analyses of two urban areas within those states (St. Louis, New York City), were conducted in 2010. The percentage of tobacco retailers falling within 350-, 500-, and 1000-foot buffer zones was then calculated. 22% of retailers in Missouri and 51% in New York fall within 1000-foot buffers around schools. In urban settings, more retailers are affected, 29% in St. Louis and 79% in New York City. Sensitivity analyses demonstrate that smaller buffers decrease the proportion of affected retailers. That is, 350-foot buffers affect only 6.7% of retailers in St. Louis and 29% in New York City. The effects of new outdoor tobacco advertising restrictions vary by location and population density. In Missouri and New York, outdoor tobacco advertising would still be permitted in many locations if such advertising was prohibited in a 1000-foot buffer zone around schools and playgrounds. Much smaller buffer zones of 350 feet may result in almost no reduction of outdoor advertising in many parts of the country. Copyright © 2011. Published by Elsevier Inc.

  16. Smokefree signage at children’s playgrounds: Field observations and comparison with Google Street View

    Directory of Open Access Journals (Sweden)

    George Thomson

    2017-08-01

    The presence and quality of smokefree signage was poor in this sample of children’s playgrounds in this developed country setting. There appears to be value in comparing smokefree signage with other types of signage (eg, dog control signage. Google Street View was not a sensitive tool for studying such signage.

  17. Thermochemical Surface Engineering: A Playground for Science and Innovation

    DEFF Research Database (Denmark)

    Christiansen, Thomas Lundin; Dahl, Kristian Vinter; Jellesen, Morten Stendahl

    2017-01-01

    Surface engineering by thermochemical processing is the intentional change of the composition of a material at elevated temperature with the purpose to improve materials performance. In thermochemical processing components from the starting material are essential in the development of the phases...... at the surface. Current research and innovation activities are used to exemplify thermochemical surface engineering and the interplay of science and innovation. The examples given encompass aspects of the synthesis of extremely porous materials, low temperature surface hardening of stainless steel, surface...

  18. Childhood obesity and parks and playgrounds: A review of issues of equality, gender and social support

    Directory of Open Access Journals (Sweden)

    Hammad Ali Qazi

    2011-01-01

    Full Text Available The childhood obesity has been a growing concern over the last decade all over the world. Built environmental characteristics such as parks and playgrounds serves as a reference point for physical activity in children. The equality issues related to ethnicity, Social Economic Status (SES, gender and social support have been related with both physical activity and presence and quality of parks and playgrounds. However, only limited studies have addressed these issues in children. The current paper is a general enumerative review that would discusses the above issues with respect to obesity in all age groups, giving particular emphasis to childhood obesity. The importance of this review is to further explore the importance and highlight the findings related to these issues, so that future original studies could be planned keeping these associations in mind.

  19. Young Boys Playing Digital Games. From Console to the Playground.

    OpenAIRE

    Pål Aarsand

    2010-01-01

    This article studies how digital games are part of the everyday lives of Swedish 6 to 7-year-old boys. The data consist of video recordings from two schools, two after-school centres and four homes. The focus is on how children engage in, organize and use digital games in face-to-face interaction. It is argued that digital game competence matters not only in front of the screen, but also in the playground. In addition, it is argued that what counts as game competence is negotiated in the peer...

  20. Entertainment Capture through Heart Rate Activity in Physical Interactive Playgrounds

    DEFF Research Database (Denmark)

    Yannakakis, Georgios; Hallam, John; Lund, Henrik Hautop

    2008-01-01

    children’s physiological signals, an estimator of the degree to which games provided by the playground engage the players. For this purpose children’s heart rate (HR) signals, and their expressed preferences of how much “fun” particular game variants are, are obtained from experiments using games...... that predict reported entertainment preferences given HR features. These models are expressed as artificial neural networks and are demonstrated and evaluated on two Playware games and two control tasks requiring physical activity. The best network is able to correctly match expressed preferences in 64...

  1. Is Recess an Achievement Context? An Application of Expectancy-Value Theory to Playground Choices

    Science.gov (United States)

    Spencer-Cavaliere, Nancy; Dunn, Janice Causgrove; Watkinson, E. Jane

    2009-01-01

    This study investigated the application of an expectancy-value model to children's activity choices on the playground at recess. The purpose was to test the prediction that expectancies for success and subjective task values are related to decisions to engage in specific recess activities such as climbing, playing soccer, or skipping rope.…

  2. Molecular characterization of Toxocara spp. eggs isolated from public parks and playgrounds in Shiraz, Iran.

    Science.gov (United States)

    Choobineh, M; Mikaeili, F; Sadjjadi, S M; Ebrahimi, S; Iranmanesh, S

    2018-05-07

    Human toxocariasis, a worldwide parasitic disease, is caused by the larval stage of intestinal nematodes of dogs and cats, namely Toxocara canis and Toxocara cati. Human infection occurs by the accidental ingestion of embryonated eggs present in the soil, vegetables or on other contaminated surfaces, as well as via consumption of uncooked paratenic hosts, such as bird meat and giblets. The objective of this study was to evaluate the contamination of soil in public parks and playgrounds in Shiraz using microscopy and molecular methods. A total of 150 soil samples were collected from public parks and playgrounds in various areas of Shiraz, southern Iran. The samples were treated with saturated zinc sulphate solution, and Toxocara spp. eggs were detected by microscopic observation followed by nested polymerase chain reaction (PCR). To differentiate T. canis and T. cati eggs from each other, PCR restriction fragment length polymorphism (RFLP) of the internal transcribed spacer (ITS)-rDNA region by SalI endonuclease enzyme was used. PCR-sequencing was performed to confirm the results of the PCR-RFLP method. Based on the flotation results of the 150 soil samples, six (4%) were found to be positive for Toxocara spp. eggs, whereas nested-PCR showed 24 samples to be positive (16%). Based on the PCR-RFLP method and the sequence of the ITS-rDNA region, a total of 23 out of 24 isolates were confirmed as T. cati and one out of 24 as T. canis. The results showed a higher number of soil samples to be positive for Toxocara by the molecular method than microscopy, and higher T. cati infection in soil samples, which could have an important role in human infection with toxocariasis in this region.

  3. Quantifying Peer Interactions for Research and Clinical Use: The Manchester Inventory for Playground Observation

    Science.gov (United States)

    Gibson, Jenny; Hussain, Jamilla; Holsgrove, Samina; Adams, Catherine; Green, Jonathan

    2011-01-01

    Direct observation of peer relating is potentially a sensitive and ecologically valid measure of child social functioning, but there has been a lack of standardised methods. The Manchester Inventory for Playground Observation (MIPO) was developed as a practical yet rigorous assessment of this kind for 5-11 year olds. We report on the initial…

  4. The Particle Physics Playground website: tutorials and activities using real experimental data

    Science.gov (United States)

    Bellis, Matthew; CMS Collaboration

    2016-03-01

    The CERN Open Data Portal provides access to data from the LHC experiments to anyone with the time and inclination to learn the analysis procedures. The CMS experiment has made a significant amount of data availible in basically the same format the collaboration itself uses, along with software tools and a virtual enviroment in which to run those tools. These same data have also been mined for educational exercises that range from very simple .csv files that can be analyzed in a spreadsheet to more sophisticated formats that use ROOT, a dominant software package in experimental particle physics but not used as much in the general computing community. This talk will present the Particle Physics Playground website (http://particle-physics-playground.github.io/), a project that uses data from the CMS experiment, as well as the older CLEO experiment, in tutorials and exercises aimed at high school and undergraduate students and other science enthusiasts. The data are stored as text files and the users are provided with starter Python/Jupyter notebook programs and accessor functions which can be modified to perform fairly high-level analyses. The status of the project, success stories, and future plans for the website will be presented. This work was supported in part by NSF Grant PHY-1307562.

  5. Science Outreach for the Thousands: Coe College's Playground of Science

    Science.gov (United States)

    Watson, D. E.; Franke, M.; Affatigato, M.; Feller, S.

    2011-12-01

    Coe College is a private liberal arts college nestled in the northeast quadrant of Cedar Rapids, IA. Coe takes pride in the outreach it does in the local community. The sciences at Coe find enjoyment in educating the children and families of this community through a diverse set of venues; from performing science demonstrations for children at Cedar Rapids' Fourth of July Freedom Festival to hosting summer forums and talks to invigorate the minds of its more mature audiences. Among these events, the signature event of the year is the Coe Playground of Science. On the last Thursday of October, before Halloween, the science departments at Coe invite nearly two thousand children from pre elementary to high school ages, along with their parents to participate in a night filled with science demos, haunted halls, and trick-or-treating for more than just candy. The demonstrations are performed by professors and students alike from a raft of cooperative departments including physics, chemistry, biology, math, computer science, nursing, ROTC, and psychology. This event greatly strengthens the relationships between institution members and community members. The sciences at Coe understand the importance of imparting the thrill and hunger for exploration and discovery into the future generations. More importantly they recognize that this cannot start and end at the collegiate level, but the American public must be reached at younger ages and continue to be encouraged beyond the college experience. The Playground of Science unites these two groups under the common goal of elevating scientific interest in the American people.

  6. Motor Skill Development in Italian Pre-School Children Induced by Structured Activities in a Specific Playground.

    Science.gov (United States)

    Tortella, Patrizia; Haga, Monika; Loras, Håvard; Sigmundsson, Hermundur; Fumagalli, Guido

    2016-01-01

    This study examined the effects and specificity of structured and unstructured activities played at the playground Primo Sport 0246 in Northern Italy on motor skill competence in five years old children. The playground was specifically designed to promote gross motor skills in preschool children; in this study 71 children from local kindergartens came to the park once a week for ten consecutive weeks and were exposed to 30 minutes of free play and 30 minutes of structured activities. Before and after the ten visits, each child completed nine tests to assess levels of motor skills, three for fine-motor skills and six for gross-motor skills. As control, motor skills were also assessed on 39 children from different kindergartens who did not come to the park. The results show that the experimental group who practiced gross-motor activities in the playground for 1 hour a week for 10 weeks improved significantly in 4 out of the 6 gross motor tasks and in none of the fine motor tasks. The data indicate that limited transfer occurred between tasks referring to different domains of motor competences while suggesting cross feeding for improvement of gross-motor skills between different exercises when domains related to physical fitness and strength of specific muscle groups are involved. These results are relevant to the issue of condition(s) appropriate for maintaining and developing motor skills in this age group as well as for the planning, organization and implementation of play and physical activities in kindergartens.

  7. Motor Skill Development in Italian Pre-School Children Induced by Structured Activities in a Specific Playground.

    Directory of Open Access Journals (Sweden)

    Patrizia Tortella

    Full Text Available This study examined the effects and specificity of structured and unstructured activities played at the playground Primo Sport 0246 in Northern Italy on motor skill competence in five years old children. The playground was specifically designed to promote gross motor skills in preschool children; in this study 71 children from local kindergartens came to the park once a week for ten consecutive weeks and were exposed to 30 minutes of free play and 30 minutes of structured activities. Before and after the ten visits, each child completed nine tests to assess levels of motor skills, three for fine-motor skills and six for gross-motor skills. As control, motor skills were also assessed on 39 children from different kindergartens who did not come to the park. The results show that the experimental group who practiced gross-motor activities in the playground for 1 hour a week for 10 weeks improved significantly in 4 out of the 6 gross motor tasks and in none of the fine motor tasks. The data indicate that limited transfer occurred between tasks referring to different domains of motor competences while suggesting cross feeding for improvement of gross-motor skills between different exercises when domains related to physical fitness and strength of specific muscle groups are involved. These results are relevant to the issue of condition(s appropriate for maintaining and developing motor skills in this age group as well as for the planning, organization and implementation of play and physical activities in kindergartens.

  8. Motor Skill Development in Italian Pre-School Children Induced by Structured Activities in a Specific Playground

    Science.gov (United States)

    Tortella, Patrizia; Haga, Monika; Loras, Håvard

    2016-01-01

    This study examined the effects and specificity of structured and unstructured activities played at the playground Primo Sport 0246 in Northern Italy on motor skill competence in five years old children. The playground was specifically designed to promote gross motor skills in preschool children; in this study 71 children from local kindergartens came to the park once a week for ten consecutive weeks and were exposed to 30 minutes of free play and 30 minutes of structured activities. Before and after the ten visits, each child completed nine tests to assess levels of motor skills, three for fine-motor skills and six for gross-motor skills. As control, motor skills were also assessed on 39 children from different kindergartens who did not come to the park. The results show that the experimental group who practiced gross-motor activities in the playground for 1 hour a week for 10 weeks improved significantly in 4 out of the 6 gross motor tasks and in none of the fine motor tasks. The data indicate that limited transfer occurred between tasks referring to different domains of motor competences while suggesting cross feeding for improvement of gross-motor skills between different exercises when domains related to physical fitness and strength of specific muscle groups are involved. These results are relevant to the issue of condition(s) appropriate for maintaining and developing motor skills in this age group as well as for the planning, organization and implementation of play and physical activities in kindergartens. PMID:27462985

  9. Aggressive Forms and Functions on School Playgrounds: Profile Variations in Interaction Styles, Bystander Actions, and Victimization

    Science.gov (United States)

    Frey, Karin S.; Newman, Jodi Burrus; Onyewuenyi, Adaurennaya C.

    2014-01-01

    Coders used real-time focal-child sampling methods to observe the playground behavior and victimization experiences of 600 third to sixth grade youth. Person-centered analyses yielded three profiles that specified aggressive function (reactive, proactive) and form (direct, indirect), and conformed to social-information-processing functional…

  10. EXAMINATION OF THE SIMULATED THERMAL CONDITIONS IN A POPULAR PLAYGROUND RELATED TO THE HUMAN REACTIONS AND THE JUDGMENT OF THE AREA DESIGN

    Directory of Open Access Journals (Sweden)

    L.A. ÉGERHÁZI

    2013-03-01

    Full Text Available In the field of urban bioclimatology an important and timely research direction today is to examine the thermal conditions of public places. In our study, human thermal comfort analysis was performed in a modern and well-attended children playground located in Szeged (Hungary. The aim of the paper is to reveal the changes in the thermal comfort conditions between two seasons and also the resulting subjective thermal reactions of visitors in this relatively small area. Thermal comfort conditions were quantified by the Physiologically Equivalent Temperature (PET. For typical summer and autumn days of 2011 numerical simulations of thermal comfort conditions in the playground were carried out by means of the urban microclimate model ENVI-met. Spatial distribution of the simulated PET, i.e. thermal stress maps were created in two different times of the selected days in order to characterize the distinct microclimatological conditions appearing in the area. The relationship between the momentary spatial patterns of visitors and the thermal conditions was also under investigation. Additionally, onsite questionnaire survey was implemented which highlights the people’s subjective evaluation related to the design of the playground.

  11. Review of the Book “Digital Labor: The Internet as Playground and Factory”, Edited by Trebor Scholz

    Directory of Open Access Journals (Sweden)

    Sebastian Sevignani

    2012-12-01

    Full Text Available This article is a review of the collected volume Digital Labor: The Internet as Playground and Factory, edited by Trebor Scholz (2013 and published by Routledge, New York. The author introduces the articles, discusses them briefly, and gives an overall evaluation of the book.

  12. The Effects of Playground Markings on the Physical Self-Perceptions of 10-11-Year-Old School Children

    Science.gov (United States)

    Crust, Lee; McKenna, Jim; Spence, Jon; Thomas, Catherine; Evans, Donna; Bishop, Daniel

    2014-01-01

    Background: Significant proportions of school children in the UK do not meet the minimum recommended daily requirements of 60-min moderate-intensity physical activity. Beyond taught classes, playtimes offer the opportunity for children to play and be physically active. Painted markings are one recent addition to school playgrounds that are…

  13. Where do the children play? The influence of playground equipment on physical activity of children in free play.

    Science.gov (United States)

    Farley, Thomas A; Meriwether, Rebecca A; Baker, Erin T; Rice, Janet C; Webber, Larry S

    2008-03-01

    Promotion of physical activity in children depends on an understanding of how children use play equipment. We conducted observations over 2 years of children in 2nd through 8th grades in a schoolyard with 5 distinct play areas with different amounts of play equipment. Children were more likely to play in areas with more installed play equipment, with densities of children in equipped areas 3.3 to 12.6 times higher than in an open grassy field. There were no significant differences by play area in the percent of children who were physically active at all, but children were more likely to be very active in areas with basketball goals and an installed play structure than in an open field. Playground equipment appeared to have a strong influence on where children played and a moderate influence on levels of activity. To maximize physical activity in children, playgrounds should be designed with ample and diverse play equipment.

  14. Green and lean: Is neighborhood park and playground availability associated with youth obesity? Variations by gender, socioeconomic status, and race/ethnicity.

    Science.gov (United States)

    Morgan Hughey, S; Kaczynski, Andrew T; Child, Stephanie; Moore, Justin B; Porter, Dwayne; Hibbert, James

    2017-02-01

    Parks and park features are important for promoting physical activity and healthy weight, especially for low-income and racial/ethnic minority youth who have disproportionately high obesity rates. This study 1) examined associations between neighborhood park and playground availability and youth obesity, and 2) assessed whether these associations were moderated by youth race/ethnicity and socioeconomic status (SES). In 2013, objectively measured height and weight were collected for all 3rd-5th grade youth (n=13.469) in a southeastern US county to determine body mass index (BMI) percentiles. Enumeration and audits of the county's parks (n=103) were concurrently conducted. Neighborhood park and playground availability were calculated as the number of each facility within or intersecting each youth's Census block group. Multilevel linear regression models were utilized to examine study objectives. For boys, no main effects were detected; however, SES moderated associations such that higher park availability was associated with lower BMI percentile for low-SES youth but higher BMI percentile for high-SES youth. For girls, the number of parks and playgrounds were significantly associated with lower BMI (b=-2.2, b=-1.1, pyouth obesity by SES and race/ethnicity, highlighting the importance of studying the intersection of these characteristics when exploring associations between built environment features and obesity. Copyright © 2016 Elsevier Inc. All rights reserved.

  15. Environmental arsenic, cadmium and lead dust emissions from metal mine operations: Implications for environmental management, monitoring and human health

    Energy Technology Data Exchange (ETDEWEB)

    Taylor, Mark Patrick, E-mail: mark.taylor@mq.edu.au; Mould, Simon Anthony; Kristensen, Louise Jane; Rouillon, Marek

    2014-11-15

    Although blood lead values in children are predominantly falling globally, there are locations where lead exposure remains a persistent problem. One such location is Broken Hill, Australia, where the percentage of blood lead values >10 μg/dL in children aged 1–4 years has risen from 12.6% (2010), to 13% (2011) to 21% (2012). The purpose of this study was to determine the extent of metal contamination in places accessible to children. This study examines contemporary exposure risks from arsenic, cadmium, lead, silver and zinc in surface soil and dust, and in pre- and post-play hand wipes at six playgrounds across Broken Hill over a 5-day period in September 2013. Soil lead (mean 2,450 mg/kg) and zinc (mean 3,710 mg/kg) were the most elevated metals in playgrounds. Surface dust lead concentrations were consistently elevated (mean 27,500 μg/m{sup 2}) with the highest lead in surface dust (59,900 μg/m{sup 2}) and post-play hand wipes (60,900 μg/m{sup 2}) recorded close to existing mining operations. Surface and post-play hand wipe dust values exceeded national guidelines for lead and international benchmarks for arsenic, cadmium and lead. Lead isotopic compositions ({sup 206}Pb/{sup 207}Pb, {sup 208}Pb/{sup 207}Pb) of surface dust wipes from the playgrounds revealed the source of lead contamination to be indistinct from the local Broken Hill ore body. The data suggest frequent, cumulative and ongoing mine-derived dust metal contamination poses a serious risk of harm to children. - Highlights: 1.Playground soils and surface dust in a mining town have high metal concentrations. 2.Elevated levels of As, Cd, Pb and Zn dust are found on playground users′ hands. 3.Pb isotope analysis shows that the source of playground dust is ore body Pb. 4.Surface mine operations must be contained to reduce childhood lead exposure risks. 5.Mine environmental licences need to set trigger values for As, Cd, Pb and Zn dust.

  16. Environmental arsenic, cadmium and lead dust emissions from metal mine operations: Implications for environmental management, monitoring and human health

    International Nuclear Information System (INIS)

    Taylor, Mark Patrick; Mould, Simon Anthony; Kristensen, Louise Jane; Rouillon, Marek

    2014-01-01

    Although blood lead values in children are predominantly falling globally, there are locations where lead exposure remains a persistent problem. One such location is Broken Hill, Australia, where the percentage of blood lead values >10 μg/dL in children aged 1–4 years has risen from 12.6% (2010), to 13% (2011) to 21% (2012). The purpose of this study was to determine the extent of metal contamination in places accessible to children. This study examines contemporary exposure risks from arsenic, cadmium, lead, silver and zinc in surface soil and dust, and in pre- and post-play hand wipes at six playgrounds across Broken Hill over a 5-day period in September 2013. Soil lead (mean 2,450 mg/kg) and zinc (mean 3,710 mg/kg) were the most elevated metals in playgrounds. Surface dust lead concentrations were consistently elevated (mean 27,500 μg/m 2 ) with the highest lead in surface dust (59,900 μg/m 2 ) and post-play hand wipes (60,900 μg/m 2 ) recorded close to existing mining operations. Surface and post-play hand wipe dust values exceeded national guidelines for lead and international benchmarks for arsenic, cadmium and lead. Lead isotopic compositions ( 206 Pb/ 207 Pb, 208 Pb/ 207 Pb) of surface dust wipes from the playgrounds revealed the source of lead contamination to be indistinct from the local Broken Hill ore body. The data suggest frequent, cumulative and ongoing mine-derived dust metal contamination poses a serious risk of harm to children. - Highlights: 1.Playground soils and surface dust in a mining town have high metal concentrations. 2.Elevated levels of As, Cd, Pb and Zn dust are found on playground users′ hands. 3.Pb isotope analysis shows that the source of playground dust is ore body Pb. 4.Surface mine operations must be contained to reduce childhood lead exposure risks. 5.Mine environmental licences need to set trigger values for As, Cd, Pb and Zn dust

  17. Review of dissertation «A Comparison of Cognitive Play Skills Within a Natural and Manufactured Preschool Playground» by Kelly Groeber

    Directory of Open Access Journals (Sweden)

    Florova N.B.

    2016-03-01

    Full Text Available The article examines the structure of the game space as a factor, providing formation of creativity which in its turn is regarded as personal competence in preschool children. The data obtained by the author contribute to the general knowledge about age dynamics and typology of skills that are gained by children in the process of shaping of their playing competences. They also demonstrate the deficit of child development in conditions of artificial gaming environment, lacking natural components. The article also contains a big number of pictures, showing the functional capacities of different playgrounds, tabular figures, and volumetric methodical applicationы. The present comparative qualitative analysis is aimed at mapping cognitive skills, formed in preschool children in case they spend more time on the playgrounds, equipped with the elements of natural origin (natural or artificial ( metal elements.

  18. Playground diseños e infraestructuras seguras para nuestros niños y niñas…una urgencia en Costa Rica

    Directory of Open Access Journals (Sweden)

    María Morera-Castro

    2007-07-01

    Full Text Available Se propone en este artículo una serie de aspectos que se deben tomar en cuenta para el diseño e infraestructura de los campos de juego o playgrounds.  Además del equipamiento y componentes necesarios que faciliten la conformación de normativas de seguridad, que van a establecer un espacio seguro capaz de cumplir el objetivo de su creación, deben ser un medio que facilite  la formación integral de la población, sin poner en riesgo su salud, previniendo cualquier tipo de accidente  y garantizando sus derechos inalienables como costarricenses.   Es urgente, por tanto, que en Costa Rica se establezcan legislaciones claras que garanticen el cumplimiento en cuanto a la construcción, diseño y utilización de los playgrounds.

  19. The inner-city Skater Facility - playground or control mechanism?

    DEFF Research Database (Denmark)

    Gravesen, David Thore

    2016-01-01

    special Social services, School and Police unit), that observe, mingle and socialize at the facility. The social workers affiliated with the SSP understand and define their role in contradiction to the official agenda. The social workers seek to pull the young people off the street and get them to enroll......The inner-city Skater Facility - playground or control mechanism? In 2013, the municipality in Horsens, a medium-sized provincial town in Denmark, bestowed the city's children and young people a skater facility at the city's central squares. Officially, the municipality donated the facility to give...... local children and young people an opportunity to use their leisure time stimulating their bodies, having a great time with friends and other urban dwellers. The gift is accompanied by a number of (more or less camouflaged) crime prevention- and social education agendas, carried out by the SSP (a...

  20. Learning from the experts: exploring playground experience and activities using a write and draw technique.

    Science.gov (United States)

    Knowles, Zoe Rebecca; Parnell, Daniel; Stratton, Gareth; Ridgers, Nicola Diane

    2013-03-01

    Qualitative research into the effect of school recess on children's physical activity is currently limited. This study used a write and draw technique to explore children's perceptions of physical activity opportunities during recess. 299 children age 7-11 years from 3 primary schools were enlisted. Children were grouped into Years 3 & 4 and Years 5 & 6 and completed a write and draw task focusing on likes and dislikes. Pen profiles were used to analyze the data. Results indicated 'likes' focused on play, positive social interaction, and games across both age groups but showed an increasing dominance of games with an appreciation for being outdoors with age. 'Dislikes' focused on dysfunctional interactions linked with bullying, membership, equipment, and conflict for playground space. Football was a dominant feature across both age groups and 'likes/dislikes' that caused conflict and dominated the physically active games undertaken. Recess was important for the development of conflict management and social skills and contributed to physical activity engagement. The findings contradict suggestions that time spent in recess should be reduced because of behavioral issues.

  1. The Federal Research Action Plan on Recycled Tire Crumb Used on Playing Fields and Playgrounds - Background and Exposure Research Goals.

    Science.gov (United States)

    Concerns have been raised by the public about the safety of recycled tire crumb rubber used in synthetic turf fields and playgrounds in the United States (U.S.). Several studies have been identified that examine potential exposure to tire crumb rubber infill in these settings. Th...

  2. Unspoken Playground Rules Discourage Adolescent Physical Activity in School: A Focus Group Study of Constructs in the Prototype Willingness Model.

    Science.gov (United States)

    Wheatley, Catherine M; Davies, Emma L; Dawes, Helen

    2018-03-01

    The health benefits of exercise in school are recognized, yet physical activity continues to decline during early adolescence despite numerous interventions. In this study, we investigated whether the prototype willingness model, an account of adolescent decision making that includes both reasoned behavioral choices and unplanned responses to social environments, might improve understanding of physical activity in school. We conducted focus groups with British pupils aged 12 to 13 years and used deductive thematic analysis to search for themes relating to the model. Participants described reasoned decisions about physical activity outside school and unplanned choices to be inactive during break, in response to social contexts described as more "judgmental" than in primary school. Social contexts appeared characterized by anxiety about competence, negative peer evaluation, and inactive playground norms. The prototype willingness model might more fully explain physical activity in school than reasoned behavioral models alone, indicating potential for interventions targeting anxieties about playground social environments.

  3. Federal Research Action Plan (FRAP) on Recycled Tire Crumb Used on Playing Fields and Playgrounds (5th Annual Recycled Rubber Products Technology Conference)

    Science.gov (United States)

    This presentation provides an overview and status update of the Federal Research Action Plan (FRAP) on Recycled Tire Crumb Used on Playing Fields and Playgrounds. The presentation includes information on Federal research activities, stakeholder engagement, other studies, and the ...

  4. Reducing phosphorus loading of surface water using iron-coated sand

    NARCIS (Netherlands)

    Groenenberg, J.E.; Chardon, W.J.; Koopmans, G.F.

    2013-01-01

    Phosphorus losses from agricultural soils is an important source of P in surface waters leading to surface water quality impairment. In addition to reducing P inputs, mitigation measures are needed to reduce P enrichment of surface waters. Because drainage of agricultural land by pipe drainage is an

  5. The Sydney playground project: popping the bubblewrap--unleashing the power of play: a cluster randomized controlled trial of a primary school playground-based intervention aiming to increase children's physical activity and social skills.

    Science.gov (United States)

    Bundy, Anita C; Naughton, Geraldine; Tranter, Paul; Wyver, Shirley; Baur, Louise; Schiller, Wendy; Bauman, Adrian; Engelen, Lina; Ragen, Jo; Luckett, Tim; Niehues, Anita; Stewart, Gabrielle; Jessup, Glenda; Brentnall, Jennie

    2011-09-01

    In the Westernised world, numerous children are overweight and have problems with bullying and mental health. One of the underlying causes for all three is postulated to be a decrease in outdoor free play. The aim of the Sydney Playground Project is to demonstrate the effectiveness of two simple interventions aimed to increase children's physical activity and social skills. This study protocol describes the design of a 3-year cluster randomised controlled trial (CRCT), in which schools are the clusters. The study consists of a 13-week intervention and 1 week each of pre-and post-testing. We are recruiting 12 schools (6 control; 6 intervention), with 18 randomly chosen participants aged 5 to 7 years in each school. The two intervention strategies are: (1) Child-based intervention: Unstructured materials with no obvious play value introduced to the playground; and (2) Adult-based intervention: Risk reframing sessions held with parents and teachers with the aim of exploring the benefits of allowing children to engage in activities with uncertain outcomes. The primary outcome of the study, physical activity as measured by accelerometer counts, is assessed at baseline and post-intervention. Additional assessments include social skills and interactions, self-concept, after school time use and anthropometric data. Qualitative data (i.e., transcriptions of audio recordings from the risk reframing sessions and of interviews with selected teacher and parent volunteers) are analysed to understand their perceptions of risk in play. The control schools have recess as usual. In addition to outcome evaluation, regular process evaluation sessions are held to monitor fidelity to the treatment. These simple interventions, which could be adopted in every primary school, have the potential of initiating a self-sustaining cycle of prevention for childhood obesity, bullying and mental ill health. Australian and New Zealand Clinical Trials Registration Number ACTRN12611000089932.

  6. The sydney playground project: popping the bubblewrap - unleashing the power of play: a cluster randomized controlled trial of a primary school playground-based intervention aiming to increase children's physical activity and social skills

    Science.gov (United States)

    2011-01-01

    Background In the Westernised world, numerous children are overweight and have problems with bullying and mental health. One of the underlying causes for all three is postulated to be a decrease in outdoor free play. The aim of the Sydney Playground Project is to demonstrate the effectiveness of two simple interventions aimed to increase children's physical activity and social skills. Methods/Design This study protocol describes the design of a 3-year cluster randomised controlled trial (CRCT), in which schools are the clusters. The study consists of a 13-week intervention and 1 week each of pre-and post-testing. We are recruiting 12 schools (6 control; 6 intervention), with 18 randomly chosen participants aged 5 to 7 years in each school. The two intervention strategies are: (1) Child-based intervention: Unstructured materials with no obvious play value introduced to the playground; and (2) Adult-based intervention: Risk reframing sessions held with parents and teachers with the aim of exploring the benefits of allowing children to engage in activities with uncertain outcomes. The primary outcome of the study, physical activity as measured by accelerometer counts, is assessed at baseline and post-intervention. Additional assessments include social skills and interactions, self-concept, after school time use and anthropometric data. Qualitative data (i.e., transcriptions of audio recordings from the risk reframing sessions and of interviews with selected teacher and parent volunteers) are analysed to understand their perceptions of risk in play. The control schools have recess as usual. In addition to outcome evaluation, regular process evaluation sessions are held to monitor fidelity to the treatment. Discussion These simple interventions, which could be adopted in every primary school, have the potential of initiating a self-sustaining cycle of prevention for childhood obesity, bullying and mental ill health. Trial registration Australian and New Zealand Clinical

  7. The sydney playground project: popping the bubblewrap - unleashing the power of play: a cluster randomized controlled trial of a primary school playground-based intervention aiming to increase children's physical activity and social skills

    Directory of Open Access Journals (Sweden)

    Luckett Tim

    2011-09-01

    Full Text Available Abstract Background In the Westernised world, numerous children are overweight and have problems with bullying and mental health. One of the underlying causes for all three is postulated to be a decrease in outdoor free play. The aim of the Sydney Playground Project is to demonstrate the effectiveness of two simple interventions aimed to increase children's physical activity and social skills. Methods/Design This study protocol describes the design of a 3-year cluster randomised controlled trial (CRCT, in which schools are the clusters. The study consists of a 13-week intervention and 1 week each of pre-and post-testing. We are recruiting 12 schools (6 control; 6 intervention, with 18 randomly chosen participants aged 5 to 7 years in each school. The two intervention strategies are: (1 Child-based intervention: Unstructured materials with no obvious play value introduced to the playground; and (2 Adult-based intervention: Risk reframing sessions held with parents and teachers with the aim of exploring the benefits of allowing children to engage in activities with uncertain outcomes. The primary outcome of the study, physical activity as measured by accelerometer counts, is assessed at baseline and post-intervention. Additional assessments include social skills and interactions, self-concept, after school time use and anthropometric data. Qualitative data (i.e., transcriptions of audio recordings from the risk reframing sessions and of interviews with selected teacher and parent volunteers are analysed to understand their perceptions of risk in play. The control schools have recess as usual. In addition to outcome evaluation, regular process evaluation sessions are held to monitor fidelity to the treatment. Discussion These simple interventions, which could be adopted in every primary school, have the potential of initiating a self-sustaining cycle of prevention for childhood obesity, bullying and mental ill health. Trial registration Australian

  8. Energy Expenditure in Playground Games in Primary School Children Measured by Accelerometer and Heart Rate Monitors.

    Science.gov (United States)

    García-Prieto, Jorge Cañete; Martinez-Vizcaino, Vicente; García-Hermoso, Antonio; Sánchez-López, Mairena; Arias-Palencia, Natalia; Fonseca, Juan Fernando Ortega; Mora-Rodriguez, Ricardo

    2017-10-01

    The aim of this study was to examine the energy expenditure (EE) measured using indirect calorimetry (IC) during playground games and to assess the validity of heart rate (HR) and accelerometry counts as indirect indicators of EE in children´s physical activity games. 32 primary school children (9.9 ± 0.6 years old, 19.8 ± 4.9 kg · m -2 BMI and 37.6 ± 7.2 ml · kg -1 · min -1 VO 2max ). Indirect calorimetry (IC), accelerometry and HR data were simultaneously collected for each child during a 90 min session of 30 playground games. Thirty-eight sessions were recorded in 32 different children. Each game was recorded at least in three occasions in other three children. The intersubject coefficient of variation within a game was 27% for IC, 37% for accelerometry and 13% for HR. The overall mean EE in the games was 4.2 ± 1.4 kcals · min -1 per game, totaling to 375 ± 122 kcals/per 90 min/session. The correlation coefficient between indirect calorimetry and accelerometer counts was 0.48 (p = .026) for endurance games and 0.21 (p = .574) for strength games. The correlation coefficient between indirect calorimetry and HR was 0.71 (p = .032) for endurance games and 0.48 (p = .026) for strength games. Our data indicate that both accelerometer and HR monitors are useful devices for estimating EE during endurance games, but only HR monitors estimates are accurate for endurance games.

  9. Playground slide-related injuries in preschool children: increased risk of lower extremity injuries when riding on laps.

    Science.gov (United States)

    Jennissen, Charles A; Koos, Maggie; Denning, Gerene

    2018-04-10

    The purpose of this study was to better understand the factors associated with playground slide-related injuries in preschool children and to test the hypothesis that riding on laps increases the likelihood of lower extremity injuries. Playground slide-related injuries (product code 1242) in children ≤5 years of age treated in emergency departments from 2002 to 2015 were identified (N = 12,686) using the U.S. Consumer Product Safety Commission's National Electronic Injury Surveillance System (NEISS). Descriptive and comparative analyses, including chi-square testing and binary logistic regression, were performed. Based on NEISS stratified national sampling estimates, over 350,000 children ≤5 years of age were injured on slides from 2002 to 2015. Overall, 59% of the children were male, and 65% were white. Almost 60% of injuries occurred in parks or other public areas. The most frequent diagnosis was a fracture (36%); lacerations were 19% of the injuries. A higher proportion of musculoskeletal injuries were seen in toddlers < 3 years old as compared to those 3-5 years of age (p < 0.001). Injuries to the lower extremities increased in frequency as age decreased, whereas injuries to the upper extremities and head/neck/face were more common in older preschoolers. Children < 3 years of age were 12 times more likely to be identified from narratives as being on another person's lap at the time of injury. Children identified as being on a lap had an increased odds of injury to the lower extremity than to other body parts (OR 43.0, 95% confidence interval (CI) 32.0-58.0), and of lower leg/ankle fracture than fractures elsewhere (OR 49.5, 95% CI 31.7-77.4). Decreasing age was associated with a higher likelihood of being identified as sliding down on another person's lap and a higher likelihood of lower extremity injuries. Healthcare providers should be mindful of the potential for these slide-related injuries as they can result in a toddler's fracture of

  10. Heavy metal exposure and risk charaterization of topsoils in urban playgrounds and parks (Hungary)

    Science.gov (United States)

    Puskás, Irén; Farsang, Andrea; Csépe, Zoltán; Bartus, Máté

    2014-05-01

    Contamination in urban soils can directly pose significant human risks through oral ingestion, particle inhalation and dermal contact, especially in public spaces. Parks and playgrounds are green areas in cities where dwellers (mainly children and seniors) can spend their outside freetime, thus the highest possibility of the human and soil interaction can be presumed here. Therefore, in 2013, composite surface samples (0-5 cm, from 10-15 subsoil samples) were collected from 96 public parks and 89 playgrounds (around playing equipment) of main functional zones (downtown, housing estates, industrial, prestigious, commuting areas) of three Hungarian cities (Budapest, Szeged, Gyula) representing capital, regional city and local town. Pseudo total metal content (Mn, Ni, Pb, Zn, As, Cd, Cr, Cu, Ba, Co) and physical, chemical soil properties influencing metal mobility (artefact, mechanical soil type, carbonate, humus, pH(H2O), salt) were determined to evaluate impacts of various anthropogenic activities in functional zones on the studied soils; to give the environmental buffering capacity and to model human health risk of exposure pathways (by RISC 4.0 ) in the case of contaminated soils. Insignificant amount of artefact, neutral pH, high humus and carbonate content, mainly loamy and loamy-clay texture, low salt content can provide suitable buffering capacity for the studied soils. The type and spatial location of functional zones have not exerted considerable impact on variability of soil properties. Out of 189 analyzed areas, 36 have exceeded the threshold values regulated by Hungarian government (6/2009. (IV. 14) KvVM-EüM-FVM collective decree). Based on quantitative and qualitative evaluation of results, the identification of spatial patterns and the possible source of metal pollution have been carried out. In accordance with statistical analysis (correlation, cluster, factor analysis), we can explore relationship between metal concentrations and features of sample

  11. Surface nanocrystallization of stainless steel for reduced biofilm adherence

    International Nuclear Information System (INIS)

    Yu Bin; Li, D Y; Davis, Elisabeth M; Irvin, Randall T; Hodges, Robert S

    2008-01-01

    Stainless steel is one of the most common metallic biomedical materials. For medical applications, its resistance to the adherence of biofilms is of importance to the elimination or minimization of bacterial infections. In this study, we demonstrate the effectiveness of a process combining surface nanocrystallization and thermal oxidation (or a recovery heat treatment in air) for reducing the biofilm's adherence to stainless steel. During this treatment, a target surface was sandblasted and the resultant dislocation cells in the surface layer were turned into nanosized grains by a subsequent recovery treatment in air. This process generated a more protective oxide film that blocked the electron exchange or reduced the surface activity more effectively. As a result, the biofilm's adherence to the treated surface was markedly minimized. A synthetic peptide was utilized as a substitute of biofilms to evaluate the adhesion between a treated steel surface and biofilms using an atomic force microscope (AFM) through measuring the adhesive force between the target surface and a peptide-coated AFM tip. It was shown that the adhesive force decreased with a decrease in the grain size of the steel. The corresponding surface electron work function (EWF) of the steel was also measured, which showed a trend of variation in EWF with the grain size, consistent with corresponding changes in the adhesive force

  12. The Sydney playground project--levelling the playing field: a cluster trial of a primary school-based intervention aiming to promote manageable risk-taking in children with disability.

    Science.gov (United States)

    Bundy, Anita C; Wyver, Shirley; Beetham, Kassia S; Ragen, Jo; Naughton, Geraldine; Tranter, Paul; Norman, Richard; Villeneuve, Michelle; Spencer, Grace; Honey, Anne; Simpson, Judith; Baur, Louise; Sterman, Julia

    2015-11-14

    Providing children and adults with opportunities to engage in manageable risk taking may be a stepping stone toward closing the gap in life conditions currently experienced by young people with disabilities. We aim to demonstrate the effectiveness of a simple, innovative program for 1) changing the way parents and teachers view manageable risk-taking for children with disabilities and 2) increasing the level of responsibility that children take for their own actions, as seen on the school playground. We will employ a cluster repeated measures trial with six Sydney-area primary-school-based programs for children with disabilities. The intervention comprises two arms. 1) Risk-reframing--teachers and parents will participate together in small group intervention sessions focusing on the benefits of manageable risk-taking; 2) Introduction of play materials--materials without a defined purpose and facilitative of social cooperation will be introduced to the school playground for children to use at all break times. A control period will be undertaken first for two school terms, followed by two terms of the intervention period. Outcome measures will include playground observations, The Coping Inventory, qualitative field notes, and The Tolerance of Risk in Play Scale. New national programs, such as Australia's National Disability Insurance Scheme, will place increasing demands on young people with disabilities to assume responsibility for difficult decisions regarding procuring services. Innovative approaches, commencing early in life, are required to prepare young people and their carers for this level of responsibility. This research offers innovative intervention strategies for promoting autonomy in children with disabilities and their carers. Australian and New Zealand Clinical Trials Registration Number ACTRN12614000549628 (registered 22/5/2014).

  13. EXAMINATION OF THE SIMULATED THERMAL CONDITIONS IN A POPULAR PLAYGROUND RELATED TO THE HUMAN REACTIONS AND THE JUDGMENT OF THE AREA DESIGN

    OpenAIRE

    L.A. ÉGERHÁZI; A. KOVÁCS; N. KÁNTOR; J. UNGER

    2013-01-01

    In the field of urban bioclimatology an important and timely research direction today is to examine the thermal conditions of public places. In our study, human thermal comfort analysis was performed in a modern and well-attended children playground located in Szeged (Hungary). The aim of the paper is to reveal the changes in the thermal comfort conditions between two seasons and also the resulting subjective thermal reactions of visitors in this relatively small area. Thermal comfort conditi...

  14. "Pre-schoolers in the playground" an outdoor physical activity intervention for children aged 18 months to 4 years old: study protocol for a pilot cluster randomised controlled trial.

    Science.gov (United States)

    Barber, Sally E; Jackson, Cath; Akhtar, Shaheen; Bingham, Daniel D; Ainsworth, Hannah; Hewitt, Catherine; Richardson, Gerry; Summerbell, Carolyn D; Pickett, Kate E; Moore, Helen J; Routen, Ash C; O'Malley, Claire L; Brierley, Shirley; Wright, John

    2013-10-09

    The pre-school years are considered critical for establishing healthy lifestyle behaviours such as physical activity. Levels of physical activity track through childhood into adulthood, thus establishing habitual physical activity early in life is vital. Time spent outdoors is associated with greater physical activity and playground interventions have been shown to increase physical activity in school aged children. There are few pre-school, playground-based interventions, and evaluations of these have found mixed results. A recent report published by the UK Chief Medical Officer (CMO) highlighted that new interventions to promote movement in the early years (0-5 years old) are needed. The aim of this study is to undertake a pilot cluster randomised controlled trial (RCT) of an outdoor playground-based physical activity intervention for parents and their children aged 18 months to 4 years old ("Pre-schoolers in the Playground"; PiP) and to assess the feasibility of conducting a full scale cluster RCT. The PiP intervention is grounded in behavioural theory (Social Cognitive Theory), and is in accordance with the CMO guidance for physical activity in the early years. It is informed by existing literature and data collected from focus groups with parents. One hundred and fifty pre-school children affiliated to 10 primary schools will be recruited. Schools will be randomised to either the PiP intervention arm or the control arm (usual practice). Children in the intervention arm will be invited to attend three 30 minute outdoor play sessions per week for 30 weeks (3 school terms) at the school. Feasibility will be assessed by examining recruitment rates, attendance, attrition, acceptability of the trial and of the PiP intervention to parents, fidelity of intervention implementation, capability and capacity for schools to deliver the intervention. Health outcomes and the feasibility of outcome measurement tools will be assessed. These include physical activity via

  15. Thermomechanical Mechanisms of Reducing Ice Adhesion on Superhydrophobic Surfaces.

    Science.gov (United States)

    Cohen, N; Dotan, A; Dodiuk, H; Kenig, S

    2016-09-20

    Superhydrophobic (SH) coatings have been shown to reduce freezing and ice nucleation rates, by means of low surface energy chemistry tailored with nano/micro roughness. Durability enhancement of SH surfaces is a crucial issue. Consequently, the present research on reducing ice adhesion is based on radiation-induced radical reaction for covalently bonding SiO2 nanoparticles to polymer coatings to obtain durable roughness. Results indicated that the proposed approach resulted in SH surfaces having high contact angles (>155°) and low sliding angles (reduction of shear adhesion to a variety of SH treated substrates having low thermal expansion coefficient (copper and aluminum) and high thermal expansion coefficient (polycarbonate and poly(methyl methacrylate)). It was concluded that the thermal mismatch between the adhering ice and the various substrates and its resultant interfacial thermal stresses affect the adhesion strength of the ice to the respective substrate.

  16. Biochar-amended filter socks reduce herbicide losses via tile line surface inlets

    Science.gov (United States)

    Standing water in depressions and behind terraces in fields with subsurface drainage systems can result in reduced crop yields. This concern can be partially alleviated by installing surface inlets that reduce the duration of ponding. Unfortunately, these inlets provide an open conduit for surface w...

  17. MULTIPLE IMAGING TECHNIQUES DEMONSTRATE THE MANIPULATION OF SURFACES TO REDUCE BACTERIAL CONTAMINATION

    Science.gov (United States)

    Surface imaging techniques were combined to determine appropriate manipulation of technologically important surfaces for commercial applications. Stainless steel surfaces were engineered to reduce bacterial contamination, biofilm formation, and corrosion during product processing...

  18. Reducing ZnO nanoparticle cytotoxicity by surface modification.

    Science.gov (United States)

    Luo, Mingdeng; Shen, Cenchao; Feltis, Bryce N; Martin, Lisandra L; Hughes, Anthony E; Wright, Paul F A; Turney, Terence W

    2014-06-07

    Nanoparticulate zinc oxide (ZnO) is one of the most widely used engineered nanomaterials and its toxicology has gained considerable recent attention. A key aspect for controlling biological interactions at the nanoscale is understanding the relevant nanoparticle surface chemistry. In this study, we have determined the disposition of ZnO nanoparticles within human immune cells by measurement of total Zn, as well as the proportions of extra- and intracellular dissolved Zn as a function of dose and surface coating. From this mass balance, the intracellular soluble Zn levels showed little difference in regard to dose above a certain minimal level or to different surface coatings. PEGylation of ZnO NPs reduced their cytotoxicity as a result of decreased cellular uptake arising from a minimal protein corona. We conclude that the key role of the surface properties of ZnO NPs in controlling cytotoxicity is to regulate cellular nanoparticle uptake rather than altering either intracellular or extracellular Zn dissolution.

  19. Food-safe modification of stainless steel food processing surfaces to reduce bacterial biofilms.

    Science.gov (United States)

    Awad, Tarek Samir; Asker, Dalal; Hatton, Benjamin D

    2018-06-11

    Biofilm formation on stainless steel (SS) surfaces of food processing plants, leading to foodborne illness outbreaks, is enabled by the attachment and confinement within microscale cavities of surface roughness (grooves, scratches). We report Foodsafe Oil-based Slippery Coatings (FOSCs) for food processing surfaces that suppress bacterial adherence and biofilm formation by trapping residual oil lubricant within these surface cavities to block microbial growth. SS surfaces were chemically functionalized with alkylphosphonic acid to preferentially wet a layer of food grade oil. FOSCs reduced the effective surface roughness, the adhesion of organic food residue, and bacteria. FOSCs significantly reduced Pseudomonas aeruginosa biofilm formation on standard roughness SS-316 by 5 log CFU cm-2, and by 3 log CFU cm-2 for mirror-finished SS. FOSCs also enhanced surface cleanability, which we measured by bacterial counts after conventional detergent cleaning. Importantly, both SS grades maintained their anti-biofilm activity after erosion of the oil layer by surface wear with glass beads, which suggests there is a residual volume of oil that remains to block surface cavity defects. These results indicate the potential of such low-cost, scalable approaches to enhance the cleanability of SS food processing surfaces and improve food safety by reducing biofilm growth.

  20. Polaron-mediated surface reconstruction in the reduced Rutile TiO2 (110) surface

    Science.gov (United States)

    Reticcioli, Michele; Setvin, Martin; Hao, Xianfeng; Diebold, Ulrike; Franchini, Cesare

    The role of polarons is of key importance for the understanding of the fundamental properties and functionalities of TiO2. We use density functional theory with an on-site Coulomb interaction and molecular dynamics to study the formation and dynamics of small polarons in the reduced rutile (110) surface. We show that excess electrons donated by oxygen-vacancies (VO) form mobile small polarons that hop easily in subsurface and surface Ti-sites. The polaron formation becomes more favorable by increasing the VO concentration level (up to 20%) due to the progressively lower energy cost needed to distort the lattice. However, at higher VO concentration the shortening of the averaged polaron-polaron distance leads to an increased Coulomb repulsion among the trapped charges at the Ti-sites, which weakens this trend. This instability is overtaken by means of a structural 1 × 2 surface reconstruction, characterized by a distinctively more favorable polaron distribution. The calculations are validated by a direct comparison with experimental AFM and STM data. Our study identifies a fundamentally novel mechanism to drive surface reconstructions and resolves a long standing issue on the origin of the reconstruction in rutile (110) surface.

  1. NORD STREAM 2 and its Soft Power – an Unfolding Playground for the European Union

    Directory of Open Access Journals (Sweden)

    Roxana Ioana Banciu

    2016-06-01

    Full Text Available This paper focuses on the Nord Stream 2 pipeline in a double reflection (Russia - the candle, Germany - the mirror handling one particular aspect that influences Russia-EU relations since the Ukrainian factor emerged as a playground for both East and West tectonic plates - namely the energy sector. It is vital for any global power to understand this approach in order to reach people’s minds, in order to emerge as leaders on the world map and to build a strong perception over a political scene. A recently debated subject is Nord Stream 2. The reason why I have chosen to explore this subject is because I am very interested in how Kremlin seeks to have an exclusive control over Eastern Europe, given the full debate in the last three years. In this thesis I will also discuss some important elements of the Russian Soft Power over Europe introducing the plot of South Stream project.

  2. Surface treatment to reduce icing; Oberflaechenbehandlung zur Vereisungsverringerung

    Energy Technology Data Exchange (ETDEWEB)

    Hoffmann, P.; Kulik, G.; Zehnder, M.

    2003-07-01

    This final report for the Swiss Federal Office of Energy (SFOE) presents the results of work done at the Swiss Federal Institute of Technology in Lausanne, Switzerland, on reducing ice formation on the evaporators of air-water heat-pumps and speeding-up the defrosting cycle by making their surfaces hydrophobic. The authors report that highest water repellence was achieved by high surface roughness and application of a strongly hydrophobic per fluorosilane coating. The results of tests carried out with uncoated and differently coated sample heat exchangers are presented. Three geometrically identical miniaturised heat exchangers were used that differed in roughness and surface wettability. Surprisingly, the rough and strongly repellent heat-exchanger showed worse defrosting behaviour than the uncoated heat-exchanger. The flat and hydrophobic-coated heat-exchanger showed the best performance. The amount of frost formed was 25% less and defrosting time was much shorter.

  3. Explore the Playground of Books: Tips for Parents of Beginning Readers = Explore el mundo de los libros: Ideas para los padres de ninos que apenas comienzan a leer.

    Science.gov (United States)

    Travaline, Kathleen A.

    To a young child just learning to read, the world of books and stories is like a big playground waiting to be explored. Children between the ages of four and six usually start to recognize some words on a page. There are many things parents can do to help their children grow as readers. Parents can support their child's reading by being patient,…

  4. Environmental contamination with Toxocara spp. eggs in public parks and playground sandpits of Greater Lisbon, Portugal.

    Science.gov (United States)

    Otero, David; Alho, Ana M; Nijsse, Rolf; Roelfsema, Jeroen; Overgaauw, Paul; Madeira de Carvalho, Luís

    Toxocarosis is a zoonotic parasitic disease transmitted from companion animals to humans. Environmental contamination with Toxocara eggs is considered to be the main source of human infections. In Portugal, knowledge regarding the current situation, including density, distribution and environmental contamination by Toxocara spp., is largely unknown. The present study investigated environmental contamination with Toxocara spp. eggs, in soil and faecal samples collected from public parks and playground sandpits in Greater Lisbon, Portugal. A total of 151 soil samples and 135 canine faecal samples were collected from 7 public sandpits and 12 public parks, over a 4 month-period. Soil samples were tested by a modified centrifugation and sedimentation/flotation technique and faecal samples were tested by an adaptation of the Cornell-Wisconsin method. Molecular analysis and sequencing were performed to discriminate Toxocara species in the soil. Overall, 85.7% of the sandpits (6/7) and 50.0% of the parks (6/12) were contaminated with Toxocara spp. eggs. The molecular analysis of soil samples showed that, 85.5% of the sandpits and 34.4% of the parks were contaminated with Toxocara cati eggs. Faecal analysis showed that 12.5% of the sandpits and 3.9% of the parks contained Toxocara canis eggs. In total, 53.0% of soil and 5.9% of faecal samples were positive for Toxocara spp. Additionally, 56.0% of the eggs recovered from the samples were embryonated after 60 days of incubation, therefore considered viable and infective. The average density was 4.2 eggs per hundred grams of soil. Public parks and playground sandpits in the Lisbon area were found to be heavily contaminated with T. cati eggs, representing a serious menace to public health as the studied areas represent common places where people of all ages, particularly children, recreate. This study sounds an alarm bell regarding the necessity to undertake effective measures such as reduction of stray animals, active faecal

  5. Elastic-plastic finite element analyses for reducers with constant-depth internal circumferential surface cracks

    International Nuclear Information System (INIS)

    Wu, Szu-Ying; Tsai, Bor-Jiun; Chen, Jien-Jong

    2015-01-01

    In this study, a 3-D automatic elastic-plastic finite element mesh generator is established to accurately predict the J-integral value of an arbitrary reducer with a constant-depth internal circumferential surface crack under bending and axial force. The contact pairs are used on the crack surfaces to simulate the actual contact behaviors of the crack model under loadings. In order to verify the accuracy of the proposed elastic-plastic finite element model for a reducer with a surface crack, the cracked straight pipe models are generated according to a special modeling procedure for a flawed reducer. The J-integral values along the crack front of surface crack are calculated and compared with the straight pipe models which have been verified in the previous published studies. Based on the comparison of computed results, good agreements are obtained to show the accuracy of present numerical models. More confidence on using the 3-D elastic-plastic finite element analysis for reducers with internal circumferential surface cracks can be thus established in this work

  6. Does improving surface cleaning and disinfection reduce health care-associated infections?

    Science.gov (United States)

    Donskey, Curtis J

    2013-05-01

    Contaminated environmental surfaces provide an important potential source for transmission of health care-associated pathogens. In recent years, a variety of interventions have been shown to be effective in improving cleaning and disinfection of surfaces. This review examines the evidence that improving environmental disinfection can reduce health care-associated infections. Published by Mosby, Inc.

  7. Fabrication and characterization of stable superhydrophobic surface with good friction-reducing performance on Al foil

    Energy Technology Data Exchange (ETDEWEB)

    Li, Peipei [Key Laboratory of Ministry of Education for Special Functional Materials, Henan University, Kaifeng 475004 (China); Chen, Xinhua, E-mail: xuc0374@hotmail.com [College of Chemistry and Chemical Engineering, Xuchang University, Xuchang 461000 (China); Yang, Guangbin; Yu, Laigui [Key Laboratory of Ministry of Education for Special Functional Materials, Henan University, Kaifeng 475004 (China); Zhang, Pingyu, E-mail: pingyu@henu.edu.cn [Key Laboratory of Ministry of Education for Special Functional Materials, Henan University, Kaifeng 475004 (China)

    2014-05-01

    Graphical abstract: A lotus-leaf-like hierarchical structure was successfully created on Al foil by a facile three-step solution–immersion method. As-obtained etched-immersed Al/STA rough surface contains interconnected convex–concave micro-structure and uniformly distributed nano-sheets that endow the surface with excellent superhydrophobicity (WCA: 164.2°; WSA: below 5°). Besides, the as-prepared etched-immersed Al/STA superhydrophobic surface on Al foil exhibits good friction-reducing ability and stable superhydrophobicity. - Highlights: • A stable superhydrophobic surface was created on aluminum foil by a facile three-step solution–immersion method. • A lotus-leaf-like hierarchical structure consists of interconnected convex–concave micro-structure and uniformly distributed nano-sheets has been constructed on the aluminum surface. • The superhydrophobic surfaces on aluminum substrate showing effective friction-reducing performance and self-cleaning ability. - Abstract: A lotus-leaf-like hierarchical structure with superhydrophobicity was created on Al foil by a facile three-step solution–immersion method involving etching in hydrochloric acid solution and immersing in hot water as well as surface-modification by stearic acid (denoted as STA). As-prepared etched-immersed Al/STA rough surface was characterized by means of scanning electron microscopy and X-ray photoelectron spectroscopy. Moreover, the water contact angles and water sliding angles of as-prepared etched-immersed Al/STA rough surface were measured, and the friction-reducing performance and self-cleaning ability of the as-prepared surface were also evaluated. Results indicate that the etched-immersed Al/STA rough surface consists of interconnected convex–concave micro-structure and uniformly distributed nano-sheets. Besides, it exhibits stable superhydrophobicity and good friction-reducing ability. Namely, it has a contact angle of water as high as 164.2° and a water sliding

  8. Fabrication and characterization of stable superhydrophobic surface with good friction-reducing performance on Al foil

    International Nuclear Information System (INIS)

    Li, Peipei; Chen, Xinhua; Yang, Guangbin; Yu, Laigui; Zhang, Pingyu

    2014-01-01

    Graphical abstract: A lotus-leaf-like hierarchical structure was successfully created on Al foil by a facile three-step solution–immersion method. As-obtained etched-immersed Al/STA rough surface contains interconnected convex–concave micro-structure and uniformly distributed nano-sheets that endow the surface with excellent superhydrophobicity (WCA: 164.2°; WSA: below 5°). Besides, the as-prepared etched-immersed Al/STA superhydrophobic surface on Al foil exhibits good friction-reducing ability and stable superhydrophobicity. - Highlights: • A stable superhydrophobic surface was created on aluminum foil by a facile three-step solution–immersion method. • A lotus-leaf-like hierarchical structure consists of interconnected convex–concave micro-structure and uniformly distributed nano-sheets has been constructed on the aluminum surface. • The superhydrophobic surfaces on aluminum substrate showing effective friction-reducing performance and self-cleaning ability. - Abstract: A lotus-leaf-like hierarchical structure with superhydrophobicity was created on Al foil by a facile three-step solution–immersion method involving etching in hydrochloric acid solution and immersing in hot water as well as surface-modification by stearic acid (denoted as STA). As-prepared etched-immersed Al/STA rough surface was characterized by means of scanning electron microscopy and X-ray photoelectron spectroscopy. Moreover, the water contact angles and water sliding angles of as-prepared etched-immersed Al/STA rough surface were measured, and the friction-reducing performance and self-cleaning ability of the as-prepared surface were also evaluated. Results indicate that the etched-immersed Al/STA rough surface consists of interconnected convex–concave micro-structure and uniformly distributed nano-sheets. Besides, it exhibits stable superhydrophobicity and good friction-reducing ability. Namely, it has a contact angle of water as high as 164.2° and a water sliding

  9. EFFECTIVENESS OF THE SANDPITS SECURITY SYSTEM AGAINST MICROORGANISMS AND INTESTINAL PARASITES SAND CONTAMINATION

    Directory of Open Access Journals (Sweden)

    Magdalena Błaszak

    2015-09-01

    Full Text Available Playgrounds and sandpits (small architecture objects according to the Construction Law are subject to meticulous supervision, both at the design stage and subsequent status checks of the objects. One of the requirements arising from the need to protect playgrounds from animals is the necessity for fencing the object (Regulation of 31 December 2002 On Safety and Hygiene in Public and Private Schools and Institutions; Polish Standard PN-EN 1176 Playground equipment and surfacing. Does fencing playgrounds really reduce contamination of sand? To verify this hypothesis, the studies have been conducted on the residential areas’ sandpits, both fence secured and unsecured, located in close proximity to one another. The aim of the study was to evaluate the effectiveness of fences and nets as protection from microbial and parasite contamination of sandpits, mainly due to the access of animals to them. For several seasons of spring and summer the sand was examined in terms of the total number of heterotrophic bacteria and fungi (organic matter contamination of sand indicators and for the presence of coliform bacteria (including Escherichia coli, bacteria of the Salmonella genus and the eggs of intestinal parasites. It can be concluded that fencing playgrounds affects sand pollution less with waste and plant material (as a consequence, it has been reported statistically significantly less heterotrophic bacteria and fungi in the fenced sandpits’ sand. Unfortunately, the fence does not eliminate the risks associated with sand pollution of coliform bacteria. Cats and birds, but also dogs, still have a continuous access to sand. Due to the repeatedly stated carelessness of children and their caregivers, gates left open to the playground do not constitute an obstacle for domestic and stray animals. Another source of sand pollution with intestinal pathogens can be a manner of carriage of new sand, as there is no legislation governing the issue of transport

  10. Can Reduced-Step Polishers Be as Effective as Multiple-Step Polishers in Enhancing Surface Smoothness?

    Science.gov (United States)

    Kemaloglu, Hande; Karacolak, Gamze; Turkun, L Sebnem

    2017-02-01

    The aim of this study was to evaluate the effects of various finishing and polishing systems on the final surface roughness of a resin composite. Hypotheses tested were: (1) reduced-step polishing systems are as effective as multiple-step systems on reducing the surface roughness of a resin composite and (2) the number of application steps in an F/P system has no effect on reducing surface roughness. Ninety discs of a nano-hybrid resin composite were fabricated and divided into nine groups (n = 10). Except the control, all of the specimens were roughened prior to be polished by: Enamel Plus Shiny, Venus Supra, One-gloss, Sof-Lex Wheels, Super-Snap, Enhance/PoGo, Clearfil Twist Dia, and rubber cups. The surface roughness was measured and the surfaces were examined under scanning electron microscope. Results were analyzed with analysis of variance and Holm-Sidak's multiple comparisons test (p One-gloss, Enamel Plus Shiny, and Venus Supra groups. (1) The number of application steps has no effect on the performance of F/P systems. (2) Reduced-step polishers used after a finisher can be preferable to multiple-step systems when used on nanohybrid resin composites. (3) The effect of F/P systems on surface roughness seems to be material-dependent rather than instrument- or system-dependent. Reduced-step systems used after a prepolisher can be an acceptable alternative to multiple-step systems on enhancing the surface smoothness of a nanohybrid composite; however, their effectiveness depends on the materials' properties. (J Esthet Restor Dent 29:31-40, 2017). © 2016 Wiley Periodicals, Inc.

  11. Study on the Effectiveness of Infiltration Wells to Reduce Excess Surface Run Off In ITB

    Directory of Open Access Journals (Sweden)

    Mardiah Afifah Muhsinatu

    2018-01-01

    Full Text Available Institut Teknologi Bandung (ITB, Ganesha Campus, Indonesia, has an area of 28.86 hectares. The campus is located in Bandung. Starting from 2012, new buildings were constructed within the area, reducing the area of permeable surface significantly. In the past few years, there were several excess run off incidents in the campus. The insufficient area of permeable surface as well as the inadequate capacity of the drainage system contributes to the excess surface run off. The drainage system has only two outlets. Moreover, in some areas, the drainage systems are disconnected. Thus, most the surface run off are stored within the drainage system. The purpose of this study is to evaluate the effectiveness of infiltration wells for reducing the local excess run off in ITB. Precipitation data and drained service area are used to estimate the design discharge from each building in ITB. In order to avoid the excess surface run off of certain locations in ITB, then the infiltration wells are proposed to balance the area of impermeable surface. The effectiveness of the infiltration wells are evaluated by assessing their number to their contribution in reducing the excess surface runs off.

  12. Surface grafting of carboxylic groups onto thermoplastic polyurethanes to reduce cell adhesion

    Energy Technology Data Exchange (ETDEWEB)

    Alves, P., E-mail: palves@eq.uc.pt [CIEPQPF, Departamento de Engenharia Química, Universidade de Coimbra, Polo II, Pinhal de Marrocos, 3030-790 Coimbra (Portugal); Ferreira, P. [CIEPQPF, Departamento de Engenharia Química, Universidade de Coimbra, Polo II, Pinhal de Marrocos, 3030-790 Coimbra (Portugal); Kaiser, Jean-Pierre [EMPA, St. Gallen, Lerchenfeldstrasse 5, CH-9014 St. Gallen (Switzerland); Salk, Natalie [Mikrofertigung – Micro Engineering, Fraunhofer IFAM, Wiener Strasse 12, D-288359 Bremen (Germany); Bruinink, Arie [EMPA, St. Gallen, Lerchenfeldstrasse 5, CH-9014 St. Gallen (Switzerland); Sousa, Hermínio C. de; Gil, M.H. [CIEPQPF, Departamento de Engenharia Química, Universidade de Coimbra, Polo II, Pinhal de Marrocos, 3030-790 Coimbra (Portugal)

    2013-10-15

    The interaction of polymers with other materials is an important issue, being their surface properties clearly crucial. For some important polymer applications, their surfaces have to be modified. Surface modification aims to tailor the surface characteristics of a material for a specific application without affecting its bulk properties. Materials can be surface modified by using biological, chemical or physical methods. The aim of this work was to improve the reactivity of the thermoplastic polyurethane (TPU) material (Elastollan{sup ®}) surface and to make its surface cell repellent by grafting carboxylic groups onto its surface. Two TPU materials were studied: a polyether-based TPU and a polyester-based TPU. The grafting efficiency was evaluated by contact angle measurements and by analytical determination of the COOH groups. Scanning electron microscopy (SEM) of the membranes surface was performed as well as cell adhesion tests. It was proved that the surfaces of the TPUs membranes were successfully modified and that cell adhesion was remarkably reduced.

  13. Reducing Surface Clutter in Cloud Profiling Radar Data

    Science.gov (United States)

    Tanelli, Simone; Pak, Kyung; Durden, Stephen; Im, Eastwood

    2008-01-01

    An algorithm has been devised to reduce ground clutter in the data products of the CloudSat Cloud Profiling Radar (CPR), which is a nadir-looking radar instrument, in orbit around the Earth, that measures power backscattered by clouds as a function of distance from the instrument. Ground clutter contaminates the CPR data in the lowest 1 km of the atmospheric profile, heretofore making it impossible to use CPR data to satisfy the scientific interest in studying clouds and light rainfall at low altitude. The algorithm is based partly on the fact that the CloudSat orbit is such that the geodetic altitude of the CPR varies continuously over a range of approximately 25 km. As the geodetic altitude changes, the radar timing parameters are changed at intervals defined by flight software in order to keep the troposphere inside a data-collection time window. However, within each interval, the surface of the Earth continuously "scans through" (that is, it moves across) a few range bins of the data time window. For each radar profile, only few samples [one for every range-bin increment ((Delta)r = 240 m)] of the surface-clutter signature are available around the range bin in which the peak of surface return is observed, but samples in consecutive radar profiles are offset slightly (by amounts much less than (Delta)r) with respect to each other according to the relative change in geodetic altitude. As a consequence, in a case in which the surface area under examination is homogenous (e.g., an ocean surface), a sequence of consecutive radar profiles of the surface in that area contains samples of the surface response with range resolution (Delta)p much finer than the range-bin increment ((Delta)p 10 dB and a reduction of the contaminated altitude over ocean from about 1 km to about 0.5 km (over the ocean). The algorithm has been embedded in CloudSat L1B processing as of Release 04 (July 2007), and the estimated flat surface clutter is removed in L2B-GEOPROF product from the

  14. Reducing extrinsic damping of surface acoustic waves at gigahertz frequencies

    Energy Technology Data Exchange (ETDEWEB)

    Gelda, Dhruv, E-mail: gelda2@illinois.edu; Sadhu, Jyothi; Ghossoub, Marc G.; Ertekin, Elif [Department of Mechanical Science and Engineering, University of Illinois, Urbana, Illinois 61801 (United States); Sinha, Sanjiv [Department of Mechanical Science and Engineering, University of Illinois, Urbana, Illinois 61801 (United States); Micro and Nanotechnology Laboratory, University of Illinois, Urbana, Illinois 61801 (United States)

    2016-04-28

    High-frequency surface acoustic waves (SAWs) in the gigahertz range can be generated using absorption from an ultrafast laser in a patterned metallic grating on a substrate. Reducing the attenuation at these frequencies can yield better sensors as well as enable them to better probe phonon and electron-phonon interactions near surfaces. It is not clear from existing experiments which mechanisms dominate damping at high frequencies. We calculate damping times of SAWs due to various mechanisms in the 1–100 GHz range to find that mechanical loading of the grating on the substrate dominates dissipation by radiating energy from the surface into the bulk. To overcome this and enable future measurements to probe intrinsic damping, we propose incorporating distributed acoustic Bragg reflectors in the experimental structure. Layers of alternating materials with contrasting acoustic impedances embedded a wavelength away from the surface serve to reflect energy back to the surface. Using numerical simulations, we show that a single Bragg reflector is sufficient to increase the energy density at the surface by more than five times. We quantify the resulting damping time to find that it is longer than the intrinsic damping time. The proposed structure can enable future measurements of intrinsic damping in SAWs at ∼100 GHz.

  15. Sex difference in choice of concealed or exposed refuge sites by preschool children viewing a model leopard in a playground simulation of antipredator behavior

    Directory of Open Access Journals (Sweden)

    Richard G. Coss

    2016-07-01

    Full Text Available The current study of preschool children characterizes a semi-natural extension of experimental questions on how human ancestors evaded predation when encountering dangerous felids. In a pretend game on a playground, we presented full-size leopard and deer models to children (N = 39 in a repeatedmeasures experimental design. Prior to viewing the model presented 15-m away, each child was instructed by the experimenter to go where she or he would feel safe. The rationale for this study was based on the anthropological construct of “sexual dinichism,” positing that, during the Pliocene, smaller-bodied hominin females engaged in more arboreal behavior than larger-bodied males. Consistent with this construct, our previous simulation research using images of an African rock outcrop showed that, after viewing a lion, girls preferred a tree as refuge rather than a crevice or large boulder whereas boys did not differentiate these refuge sites. In this follow-up study, we predicted that, after viewing the model leopard, the preschool girls would differ from the boys by not choosing enclosed refuge sites analogous to the crevice. Analyses of a contingency table for the leopard model supported this hypothesis by yielding a significant interaction of sex and refuge location (p = .031, d = .76, the source of which was a reliably larger percentage of girls not choosing concealed refuge (p = .005, d = 2.3. The interaction of sex and refuge location for the model deer was not significant (p > .5. Our findings suggest that, in contrast to the deer, the girls selected exposed playground refuge sites rather than concealing ones to maintain visual contact with the leopard as a contingency for future action

  16. Airfoil-shaped micro-mixers for reducing fouling on membrane surfaces

    Science.gov (United States)

    Ho, Clifford K; Altman, Susan J; Clem, Paul G; Hibbs, Michael; Cook, Adam W

    2012-10-23

    An array of airfoil-shaped micro-mixers that enhances fluid mixing within permeable membrane channels, such as used in reverse-osmosis filtration units, while minimizing additional pressure drop. The enhanced mixing reduces fouling of the membrane surfaces. The airfoil-shaped micro-mixer can also be coated with or comprised of biofouling-resistant (biocidal/germicidal) ingredients.

  17. Surface modification of platelet concentrate bags to reduce biofilm formation and transfusion sepsis.

    Science.gov (United States)

    Wilson-Nieuwenhuis, Joels S T; Dempsey-Hibbert, Nina; Liauw, Christopher M; Whitehead, Kathryn A

    2017-12-01

    Bacterial contamination of blood products poses a major risk in transfusion medicine, including transfusions involving platelet products. Although testing systems are in place for routine screening of platelet units, the formation of bacterial biofilms in such units may decrease the likelihood that bacteria will be detected. This work determined the surface properties of p-PVC platelet concentrate bags and investigated how these characteristics influenced biofilm formation. Serratia marcescens and Staphylococcus epidermidis, two species commonly implicated in platelet contamination, were used to study biofilm growth. The platelet concentrate bags were physically flattened to determine if reducing the surface roughness altered biofilm formation. The results demonstrated that the flattening process of the platelet bags affected the chemistry of the surface and reduced the surface hydrophobicity. Flattening of the surfaces resulted in a reduction in biofilm formation for both species after 5 days, with S. marcescens demonstrating a greater reduction. However, there was no significant difference between the smooth and flat surfaces following 7 days' incubation for S. marcescens and no significant differences between any of the surfaces following 7 days' incubation for S. epidermidis. The results suggest that flattening the p-PVC surfaces may limit potential biofilm formation for the current duration of platelet storage time of 5 days. It is hoped that this work will enhance the understanding of how surface properties influence the development of microbial biofilms in platelet concentrate bags in order to devise a solution to discourage biofilm formation. Copyright © 2017 Elsevier B.V. All rights reserved.

  18. Reducing Friction with a Liquid Film on the Body Surface

    Directory of Open Access Journals (Sweden)

    Nikolay Klyuev

    2018-03-01

    Full Text Available A flow of a thin layer of liquid is simulated on a flat surface of a body located in a stream of air. Liquid film on the surface of the body reduces frictional resistance and can be used as a boundary layer control element. The paper presents a mathematical model of the film flow on a half-plane, located at an angle to the horizon. The fluid flow is determined by the force of gravity and friction from the external air current. A model of an incompressible viscous fluid is used in the boundary-layer approximation. The terms of the motion equation are averaged over the film thickness according to the Leibniz rule. In the cross section of the film, a quadratic law is adopted for the distribution of the longitudinal velocity, taking into account friction on the film surface. An analytical solution of the problem is obtained in the form of series in powers of the small parameter for determining the film thickness and the average longitudinal velocity along the length of the plate. It is shown that the friction decreases with flow around a half-plane with a film of liquid on the surface.

  19. Method and apparatus for reducing the drag of flows over surfaces

    Science.gov (United States)

    Keefe, Laurence R. (Inventor)

    1998-01-01

    An apparatus, and its accompanying method, for reducing the drag of flows over a surface includes arrays of small disks and sensors. The arrays are embedded in the surface and may extend above, or be depressed below, the surface, provided they remain hydraulically smooth either when operating or when inactive. The disks are arranged in arrays of various shapes, and spaced according to the cruising speed of the vehicle on which the arrays are installed. For drag reduction at speeds of the order of 30 meters/second, preferred embodiments include disks that are 0.2 millimeter in diameter and spaced 0.4 millimeter apart. For drag reduction at speeds of the order of 300 meters/second, preferred embodiments include disks that are 0.045 millimeter in diameter and spaced 0.09 millimeter apart. Smaller and larger dimensions for diameter and spacing are also possible. The disks rotate in the plane of the surface, with their rotation axis substantially perpendicular to the surface. The rotating disks produce velocity perturbations parallel to the surface in the overlying boundary layer. The sensors sense the flow at the surface and connect to control circuitry that adjusts the rotation rates and duty cycles of the disks accordingly. Suction and blowing holes can be interspersed among, or made coaxial with, the disks for creating general three-component velocity perturbations in the near-surface region. The surface can be a flat, planar surface or a nonplanar surface, such as a triangular riblet surface. The present apparatus and method have potential applications in the field of aeronautics for improving performance and efficiency of commercial and military aircraft, and in other industries where drag is an obstacle, including gas and oil delivery through long-haul pipelines.

  20. Assessment of naturally occurring radioactive materials and trace elements in playgrounds of selected basic schools in the Ga-East municipal district, Accra, Ghana

    International Nuclear Information System (INIS)

    Taapopi, E.E.

    2015-07-01

    The 235 U, 232 Th series and natural 40 K are the main source of natural radioactivity in soil and have long half-lives up to 10 10 years. Therefore their presence in soils and rocks is simply considered as permanent. Also due to rapid urbanization, most of Basic School playgrounds in Accra are built close to major roads or industrial areas for which they are subject to many potential pollution sources, including vehicle exhaust and industrial emissions. A study has been carried out on playgrounds of basic schools in the Ga East municipal district in order to determine the exposure of the school children to naturally occurring radioactive materials ( 238 U, 232 Th and 40 K) and trace elements [aluminum (Al), cadmium (Cd), cobalt (Co), chromium (Cr), copper (Cu), mercury (Hg), potassium (K), lanthanum (La), manganese (Mn), sodium (Na), nickel (Ni), lead (Pb), titanium (Ti), vanadium (V), zinc (Zn)]. The activity concentrations were determined using high‐purity germanium (HPGe) detector. The average activity concentrations of 238 U, 232 Th and 40 K determined were 19.8 ± 8.7, 29.1 ± 16.3 and 119.4 ± 97.9 Bq.kg-1 respectively. The average annual effective dose was 0.039 ± 0.021 mSv and it is below the dose limit of 1 mSv/year recommended by International Commission on Radiological Protection (ICRP) for public exposure control. Radiological hazard assessments arising from the natural radionuclides were carried out. The average concentration of 222 Rn and exhalation rate were estimated to be 32.13 kBq.m -3 and 0.016 Bq.m -2 .s -1 respectively, which compared well with the world average values [78 kBq.m -3 and 0.033 Bq.m -2 .s -1 reported by (UNSCEAR, 2000)]. Soil samples were also analyzed for trace elements by Instrumental Neutron Activation Analysis and Atomic Absorption Spectrometry in order to assess the potential adverse health effects of the exposure of children to trace elements during their games at school. Doses incurred via ingestion and inhalation and

  1. Northern Alaskan land surface response to reduced Arctic sea ice extent

    Energy Technology Data Exchange (ETDEWEB)

    Higgins, Matthew E. [University of Colorado, Cooperative Institute for Research in Environmental Sciences, Boulder, CO (United States); Cassano, John J. [University of Colorado, Cooperative Institute for Research in Environmental Sciences, Department of Atmospheric and Oceanic Sciences, Boulder, CO (United States)

    2012-05-15

    With Arctic sea ice extent at near-record lows, an improved understanding of the relationship between sea ice and the land surface is warranted. We examine the land surface response to changing sea ice by first conducting a simulation using the Community Atmospheric Model version 3.1 with end of the twenty-first century sea ice extent. This future atmospheric response is then used to force the Weather and Research Forecasting Model version 3.1 to examine the terrestrial land surface response at high resolution over the North Slope of Alaska. Similar control simulations with twentieth century sea ice projections are also performed, and in both simulations only sea ice extent is altered. In the future sea ice extent experiment, atmospheric temperature increases significantly due to increases in latent and sensible heat flux, particularly in the winter season. Precipitation and snow pack increase significantly, and the increased snow pack contributes to warmer soil temperatures for most seasons by insulating the land surface. In the summer, however, soil temperatures are reduced due to increased albedo. Despite warmer near-surface atmospheric temperatures, it is found that spring melt is delayed throughout much of the North Slope due to the increased snow pack, and the growing season length is shortened. (orig.)

  2. A process to enhance the specific surface area and capacitance of hydrothermally reduced graphene oxide

    KAUST Repository

    Alazmi, Amira

    2016-08-26

    The impact of post-synthesis processing in reduced graphene oxide materials for supercapacitor electrodes has been analyzed. A comparative study of vacuum, freeze and critical point drying was carried out for hydrothermally reduced graphene oxide demonstrating that the optimization of the specific surface area and preservation of the porous network are critical to maximize its supercapacitance performance. As described below, using a supercritical fluid as the drying medium, unprecedented values of the specific surface area (364 m2 g−1) and supercapacitance (441 F g−1) for this class of materials have been achieved.

  3. A process to enhance the specific surface area and capacitance of hydrothermally reduced graphene oxide

    KAUST Repository

    Alazmi, Amira; El Tall, Omar; Rasul, Shahid; Hedhili, Mohamed N.; Patole, Shashikant P.; Da Costa, Pedro M. F. J.

    2016-01-01

    The impact of post-synthesis processing in reduced graphene oxide materials for supercapacitor electrodes has been analyzed. A comparative study of vacuum, freeze and critical point drying was carried out for hydrothermally reduced graphene oxide demonstrating that the optimization of the specific surface area and preservation of the porous network are critical to maximize its supercapacitance performance. As described below, using a supercritical fluid as the drying medium, unprecedented values of the specific surface area (364 m2 g−1) and supercapacitance (441 F g−1) for this class of materials have been achieved.

  4. Optimization of Fat-Reduced Puff Pastry Using Response Surface Methodology.

    Science.gov (United States)

    Silow, Christoph; Zannini, Emanuele; Axel, Claudia; Belz, Markus C E; Arendt, Elke K

    2017-02-22

    Puff pastry is a high-fat bakery product with fat playing a key role, both during the production process and in the final pastry. In this study, response surface methodology (RSM) was successfully used to evaluate puff pastry quality for the development of a fat-reduced version. The technological parameters modified included the level of roll-in fat, the number of fat layers (50-200) and the final thickness (1.0-3.5 mm) of the laminated dough. Quality characteristics of puff pastry were measured using the Texture Analyzer with an attached Extended Craft Knife (ECK) and Multiple Puncture Probe (MPP), the VolScan and the C-Cell imaging system. The number of fat layers and final dough thickness, in combination with the amount of roll-in fat, had a significant impact on the internal and external structural quality parameters. With technological changes alone, a fat-reduced (≥30%) puff pastry was developed. The qualities of fat-reduced puff pastries were comparable to conventional full-fat (33 wt %) products. A sensory acceptance test revealed no significant differences in taste of fatness or 'liking of mouthfeel'. Additionally, the fat-reduced puff pastry resulted in a significant ( p < 0.05) positive correlation to 'liking of flavor' and overall acceptance by the assessors.

  5. Towards Reducing the Data Exfiltration Surface for the Insider Threat

    Energy Technology Data Exchange (ETDEWEB)

    Schlicher, Bob G [ORNL; MacIntyre, Lawrence Paul [ORNL; Abercrombie, Robert K [ORNL

    2016-01-01

    Unauthorized data exfiltrations from both insiders and outsiders are costly and damaging. Network communication resources can be used for transporting data illicitly out of the enterprise or cloud. Combined with built-in malware copying utilities, we define this as comprising the Data Exfiltration Surface (DXS). For securing valuable data, it is desirable to reduce the DXS and maintain controls on the egress points. Our approach is to host the data in a protected enclave that includes novel software Data Diode (SDD) installed on a secured, border gateway. The SDD allows copying data into the enclave systems but denies data from being copied out. Simultaneously, it permits remote access with remote desktop and console applications. Our tests demonstrate that we are able to effectively reduce the DXS and we are able to protect data from being exfiltrated through the use of the SDD.

  6. Strategies for Reduced Acid and Metalliferous Drainage by Pyrite Surface Passivation

    Directory of Open Access Journals (Sweden)

    Gujie Qian

    2017-03-01

    Full Text Available Acid and metalliferous drainage (AMD is broadly accepted to be a major global environmental problem facing the mining industry, requiring expensive management and mitigation. A series of laboratory-scale kinetic leach column (KLC experiments, using both synthetic and natural mine wastes, were carried out to test the efficacy of our pyrite passivation strategy (developed from previous research for robust and sustainable AMD management. For the synthetic waste KLC tests, initial treatment with lime-saturated water was found to be of paramount importance for maintaining long-term circum-neutral pH, favourable for the formation and preservation of the pyrite surface passivating layer and reduced acid generation rate. Following the initial lime-saturated water treatment, minimal additional alkalinity (calcite-saturated water was required to maintain circum-neutral pH for the maintenance of pyrite surface passivation. KLC tests examining natural potentially acid forming (PAF waste, with much greater peak acidity than that of the synthetic waste, blended with lime (≈2 wt % with and without natural non-acid-forming (NAF waste covers, were carried out. The addition of lime and use of NAF covers maintained circum-neutral leachate pH up to 24 weeks. During this time, the net acidity generated was found to be significantly reduced by the overlying NAF cover. If the reduced rate of acidity production from the natural PAF waste is sustained, the addition of smaller (more economically-feasible amounts of lime, together with application of NAF wastes as covers, could be trialled as a potential cost-effective AMD mitigation strategy.

  7. Technical Note: Reducing the spin-up time of integrated surface water–groundwater models

    KAUST Repository

    Ajami, H.

    2014-06-26

    One of the main challenges in catchment scale application of coupled/integrated hydrologic models is specifying a catchment\\'s initial conditions in terms of soil moisture and depth to water table (DTWT) distributions. One approach to reduce uncertainty in model initialization is to run the model recursively using a single or multiple years of forcing data until the system equilibrates with respect to state and diagnostic variables. However, such "spin-up" approaches often require many years of simulations, making them computationally intensive. In this study, a new hybrid approach was developed to reduce the computational burden of spin-up time for an integrated groundwater-surface water-land surface model (ParFlow.CLM) by using a combination of ParFlow.CLM simulations and an empirical DTWT function. The methodology is examined in two catchments located in the temperate and semi-arid regions of Denmark and Australia respectively. Our results illustrate that the hybrid approach reduced the spin-up time required by ParFlow.CLM by up to 50%, and we outline a methodology that is applicable to other coupled/integrated modelling frameworks when initialization from equilibrium state is required.

  8. Technical Note: Reducing the spin-up time of integrated surface water–groundwater models

    KAUST Repository

    Ajami, H.

    2014-12-12

    One of the main challenges in the application of coupled or integrated hydrologic models is specifying a catchment\\'s initial conditions in terms of soil moisture and depth-to-water table (DTWT) distributions. One approach to reducing uncertainty in model initialization is to run the model recursively using either a single year or multiple years of forcing data until the system equilibrates with respect to state and diagnostic variables. However, such "spin-up" approaches often require many years of simulations, making them computationally intensive. In this study, a new hybrid approach was developed to reduce the computational burden of the spin-up procedure by using a combination of model simulations and an empirical DTWT function. The methodology is examined across two distinct catchments located in a temperate region of Denmark and a semi-arid region of Australia. Our results illustrate that the hybrid approach reduced the spin-up period required for an integrated groundwater–surface water–land surface model (ParFlow.CLM) by up to 50%. To generalize results to different climate and catchment conditions, we outline a methodology that is applicable to other coupled or integrated modeling frameworks when initialization from an equilibrium state is required.

  9. Optimization of Fat-Reduced Puff Pastry Using Response Surface Methodology

    Directory of Open Access Journals (Sweden)

    Christoph Silow

    2017-02-01

    Full Text Available Puff pastry is a high-fat bakery product with fat playing a key role, both during the production process and in the final pastry. In this study, response surface methodology (RSM was successfully used to evaluate puff pastry quality for the development of a fat-reduced version. The technological parameters modified included the level of roll-in fat, the number of fat layers (50–200 and the final thickness (1.0–3.5 mm of the laminated dough. Quality characteristics of puff pastry were measured using the Texture Analyzer with an attached Extended Craft Knife (ECK and Multiple Puncture Probe (MPP, the VolScan and the C-Cell imaging system. The number of fat layers and final dough thickness, in combination with the amount of roll-in fat, had a significant impact on the internal and external structural quality parameters. With technological changes alone, a fat-reduced (≥30% puff pastry was developed. The qualities of fat-reduced puff pastries were comparable to conventional full-fat (33 wt % products. A sensory acceptance test revealed no significant differences in taste of fatness or ‘liking of mouthfeel’. Additionally, the fat-reduced puff pastry resulted in a significant (p < 0.05 positive correlation to ‘liking of flavor’ and overall acceptance by the assessors.

  10. Reduced adhesion of macrophages on anodized titanium with select nanotube surface features

    Directory of Open Access Journals (Sweden)

    Balasubramanian K

    2011-08-01

    Full Text Available Amancherla Rajyalakshmi1, Batur Ercan2,3, K Balasubramanian1, Thomas J Webster2,31Non-Ferrous Materials Technology Development Centre, Hyderabad, India; 2School of Engineering, 3Department of Orthopedics, Brown University, Providence, RI, USAAbstract: One of the important prerequisites for a successful orthopedic implant apart from being osteoconductive is the elicitation of a favorable immune response that does not lead to the rejection of the implant by the host tissue. Anodization is one of the simplest surface modification processes used to create nanotextured and nanotubular features on metal oxides which has been shown to improve bone formation. Anodization of titanium (Ti leads to the formation of TiO2 nanotubes on the surface, and the presence of these nanotubes mimics the natural nanoscale features of bone, which in turn contributes to improved bone cell attachment, migration, and proliferation. However, inflammatory cell responses on anodized Ti remains to be tested. It is hypothesized that surface roughness and surface feature size on anodized Ti can be carefully manipulated to control immune cell (specifically, macrophages responses. Here, when Ti samples were anodized at 10 V in the presence of 1% hydrofluoric acid (HF for 1 minute, nanotextured (nonnanotube surfaces were created. When anodization of Ti samples was carried out with 1% HF for 10 minutes at 15 V, nanotubes with 40–50 nm diameters were formed, whereas at 20 V with 1% HF for 10 minutes, nanotubes with 60–70 nm diameters were formed. In this study, a reduced density of macrophages was observed after 24 hours of culture on nanotextured and nanotubular Ti samples which were anodized at 10, 15, and 20 V, compared with conventional unmodified Ti samples. This in vitro study thus demonstrated a reduced density of macrophages on anodized Ti, thereby providing further evidence of the greater efficacy of anodized Ti for orthopedic applications.Keywords: anodization, titanium

  11. Femtosecond laser surface texturing of titanium as a method to reduce the adhesion of Staphylococcus aureus and biofilm formation

    Energy Technology Data Exchange (ETDEWEB)

    Cunha, Alexandre [Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais 1, 1049-001 Lisboa (Portugal); Bordeaux University, Institute of Chemistry & Biology of Membranes & Nanoobjects (CBMN UMR 5248, CNRS), European Institute of Chemistry and Biology, 2 Rue Robert Escarpit, 33607 Pessac (France); Elie, Anne-Marie [Bordeaux University, CBMN UMR 5248, CNRS, Bordeaux Science Agro, 1 Rue du G. de Gaulle, 33170 Gradignan (France); Plawinski, Laurent [Bordeaux University, Institute of Chemistry & Biology of Membranes & Nanoobjects (CBMN UMR 5248, CNRS), European Institute of Chemistry and Biology, 2 Rue Robert Escarpit, 33607 Pessac (France); Serro, Ana Paula [Instituto Superior Técnico, Universidade de Lisboa, CQE-Centro de Química Estrutural, Av. Rovisco Pais 1, 1049-001 Lisbon (Portugal); Botelho do Rego, Ana Maria [Instituto Superior Técnico, Universidade de Lisboa, CQFM-Centro de Química-Física Molecular and Institute of Nanoscience and Nanotechnology - IN, Av. Rovisco Pais 1, 1049-001 Lisbon (Portugal); Almeida, Amélia [Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais 1, 1049-001 Lisboa (Portugal); Urdaci, Maria C. [Bordeaux University, CBMN UMR 5248, CNRS, Bordeaux Science Agro, 1 Rue du G. de Gaulle, 33170 Gradignan (France); Durrieu, Marie-Christine [Bordeaux University, Institute of Chemistry & Biology of Membranes & Nanoobjects (CBMN UMR 5248, CNRS), European Institute of Chemistry and Biology, 2 Rue Robert Escarpit, 33607 Pessac (France); Vilar, Rui, E-mail: rui.vilar@tecnico.ulisboa.pt [Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais 1, 1049-001 Lisboa (Portugal)

    2016-01-01

    Graphical abstract: - Highlights: • The short-term adhesion of Staphylococcus aureus onto femtosecond laser textured surfaces of titanium was investigated. • The laser textured surfaces consist of laser-induced periodic surface structures (LIPSS) and nanopillars. • The laser treatment enhances the hydrophilicity and the surface free energy of the material. • The laser treatment reduces significantly the adhesion of S. aureus and biofilm formation. • Femtosecond laser surface texturing of titanium is a simple and promising method for endowing dental and orthopedic implants with antibacterial properties. - Abstract: The aim of the present work was to investigate the possibility of using femtosecond laser surface texturing as a method to reduce the colonization of Grade 2 Titanium alloy surfaces by Staphylococcus aureus and the subsequent formation of biofilm. The laser treatments were carried out with a Yb:KYW chirped-pulse-regenerative amplification laser system with a central wavelength of 1030 nm and a pulse duration of 500 fs. Two types of surface textures, consisting of laser-induced periodic surface structures (LIPSS) and nanopillars, were produced. The topography, chemical composition and phase constitution of these surfaces were investigated by atomic force microscopy, scanning electron microscopy, X-ray photoelectron spectroscopy, micro-Raman spectroscopy, and X-ray diffraction. Surface wettability was assessed by the sessile drop method using water and diiodomethane as testing liquids. The response of S. aureus put into contact with the laser treated surfaces in controlled conditions was investigated by epifluorescence microscopy and scanning electron microscopy 48 h after cell seeding. The results achieved show that the laser treatment reduces significantly the bacterial adhesion to the surface as well as biofilm formation as compared to a reference polished surfaces and suggest that femtosecond laser texturing is a simple and promising method

  12. Radioactivity decontamination in and around school facilities in Fukushima

    International Nuclear Information System (INIS)

    Saegusa, Jun; Tagawa, Akihiro; Kurikami, Hiroshi; Iijima, Kazuki; Yoshikawa, Hideki; Tokizawa, Takayuki; Nakayama, Shinichi; Ishida, Junichiro

    2016-01-01

    Approximately two months after the Fukushima nuclear accident, the Japan Atomic Energy Agency (JAEA) led off a series of demonstration tests to develop effective but easily applicable decontamination methods for various school facilities in Fukushima. This effort included (1) dose reduction measures in schoolyards, (2) purification of swimming pool water, and (3) removal of surface contamination from playground equipment. Through these demonstration tests, they established practical methods suitable for each situation: (1) In schoolyards, dose rates were drastically reduced by removing topsoil, which was then placed in 1-m-deep trenches at a corner of the schoolyard. (2) For the purification of pool water, the flocculation coagulation treatment was found to be effective for collecting radiocesium dissolved in the water. (3) Demonstration tests for playground equipment, such as horizontal bars and a sandbox wood frame indicated that the decontamination effectiveness considerably varied depending on the material, paint or coating condition of each equipment piece. These findings were summarized in reports, some of which were compiled in local/national guidelines or handbooks for decontaminating the living environment in Fukushima. (author)

  13. Radioactivity decontamination in and around school facilities in Fukushima

    International Nuclear Information System (INIS)

    Saegusa, Jun; Iijima, Kazuki; Yoshikawa, Hideki; Ishida, Junichiro; Tagawa, Akihiro; Kurikami, Hiroshi; Nakayama, Shinichi; Tokizawa, Takayuki

    2015-01-01

    Approximately two months after the Fukushima nuclear accident, the Japan Atomic Energy Agency (JAEA) led off a series of demonstration tests to develop effective but easily applicable decontamination methods for various school facilities in Fukushima. This effort included (1) dose reduction measures in schoolyards, (2) purification of swimming pool water, and (3) removal of surface contamination from playground equipment. Through these demonstration tests, they established practical methods suitable for each situation: (1) In schoolyards, dose rates were drastically reduced by removing topsoil, which was then placed in 1-m-deep trenches at a corner of the schoolyard. (2) For the purification of pool water, the flocculation coagulation treatment was found to be effective for collecting radiocesium dissolved in the water. (3) Demonstration tests for playground equipment, such as horizontal bars and a sandbox wood frame indicated that the decontamination effectiveness considerably varied depending on the material, paint or coating condition of each equipment piece. These findings were summarized in reports, some of which were compiled in local/national guidelines or handbooks for decontaminating the living environment in Fukushima. (author)

  14. Femtosecond laser surface texturing of titanium as a method to reduce the adhesion of Staphylococcus aureus and biofilm formation

    Science.gov (United States)

    Cunha, Alexandre; Elie, Anne-Marie; Plawinski, Laurent; Serro, Ana Paula; Botelho do Rego, Ana Maria; Almeida, Amélia; Urdaci, Maria C.; Durrieu, Marie-Christine; Vilar, Rui

    2016-01-01

    The aim of the present work was to investigate the possibility of using femtosecond laser surface texturing as a method to reduce the colonization of Grade 2 Titanium alloy surfaces by Staphylococcus aureus and the subsequent formation of biofilm. The laser treatments were carried out with a Yb:KYW chirped-pulse-regenerative amplification laser system with a central wavelength of 1030 nm and a pulse duration of 500 fs. Two types of surface textures, consisting of laser-induced periodic surface structures (LIPSS) and nanopillars, were produced. The topography, chemical composition and phase constitution of these surfaces were investigated by atomic force microscopy, scanning electron microscopy, X-ray photoelectron spectroscopy, micro-Raman spectroscopy, and X-ray diffraction. Surface wettability was assessed by the sessile drop method using water and diiodomethane as testing liquids. The response of S. aureus put into contact with the laser treated surfaces in controlled conditions was investigated by epifluorescence microscopy and scanning electron microscopy 48 h after cell seeding. The results achieved show that the laser treatment reduces significantly the bacterial adhesion to the surface as well as biofilm formation as compared to a reference polished surfaces and suggest that femtosecond laser texturing is a simple and promising method for endowing dental and orthopedic titanium implants with antibacterial properties, reducing the risk of implant-associated infections without requiring immobilized antibacterial substances, nanoparticles or coatings.

  15. Reducing nitrogen leaching from fertilizers to surface waters: catchment specific indicators of economic benefits

    DEFF Research Database (Denmark)

    Andersen, Mikael Skou; Levin, Gregor; Odgaard, Mette Vestergaard

    2018-01-01

    We explore with impact pathway methodology the economic benefits of reducing nitrogen leaching to transitional surface waters, as expected for a proportionality test under the EU’s Water Framework Directive article 4. Ten different catchments is analyzed for a policy scenario where downstream dis...

  16. Si+ ion implantation reduces the bacterial accumulation on the Ti6Al4V surface

    International Nuclear Information System (INIS)

    Gallardo-Moreno, A M; Pacha-Olivenza, M A; Perera-Nunez, J; Gonzalez-Carrasco, J L; Gonzalez-Martin, M L

    2010-01-01

    Ti6Al4V is one of the most commonly used biomaterials in orthopedic applications due to its interesting mechanical properties and reasonable biocompatibility. Nevertheless, after the implantation, microbial adhesion to its surface can provoke severe health problems associated to the development of biofilms and subsequent infectious processes. This work shows a modification of the Ti6Al4V surface by Si+ ion implantation which reduces the bacterial accumulation under shear forces. Results have shown that the number of bacteria remaining on the surface at the end of the adhesion experiments decreased for silicon-treated surface. In general, the new surface also behaved as less adhesive under in vitro flow conditions. Since no changes are observed in the electrical characteristics between the control and implanted samples, differences are likely related to small changes observed in hydrophobicity.

  17. Patterned CoCrMo and Al2 O3 surfaces for reduced free wear debris in artificial joint arthroplasty.

    Science.gov (United States)

    Tarabolsi, Mohamad; Klassen, Thomas; Mantwill, Frank; Gärtner, Frank; Siegel, Frank; Schulz, Arndt-Peter

    2013-12-01

    Surface wear of corresponding tribological pairings is still a major problem in the application of artificial joint surgery. This study aims at developing wear reduced surfaces to utilize them in total joint arthroplasty. Using a pico-second laser, samples of medical CoCrMo metal alloy and Al2 O3 ceramic were patterned by laser material removal. The subsequent tribological investigations employed a ring-on-disc method. The results showed that those samples with modified surfaces show less mass or volume loss than those with a regular, smooth surface. Using calf serum as lubricating medium, the volume loss of the structured CoCrMo samples was eight times lower than that of regular samples. By structuring Al2 O3 surfaces, the wear volume could be reduced by 4.5 times. The results demonstrate that defined surface channels or pits enable the local sedimentation of wear debris. Thus, the amount of free debris could be reduced. Fewer abrasives in the lubricated so-called three-body-wear between the contact surfaces should result in less surface damage. Apart from direct influences on the wear behavior, less amounts of free debris of artificial joints should also be beneficial for avoiding undesired reactions with the surrounding soft tissues. The results from this study are very promising. Future investigations should involve the use of simulators meeting the natural conditions in the joint and in vivo studies with living organisms. Copyright © 2013 Wiley Periodicals, Inc., a Wiley Company.

  18. The Untidy Playground: An Irish Congolese Case Study in Sonic Encounters with the Sacred Stranger

    Directory of Open Access Journals (Sweden)

    Helen Phelan

    2017-11-01

    Full Text Available This paper explores the proposal that music, and particularly singing, has unique properties that render it amenable to encounters with “the other” or the sacred stranger. Drawing on the deconstructionist works of Kristeva and Derrida, as well as the postmodern hermeneutics of Kearney and Caputo, it explores current debate concerning the nature of “the sacred” in contemporary life and the erosion of the theistic/atheistic divide, while proposing a deepening of the debate through the inclusion of the performative. As philosophical and theological discourses embrace this aporia, it does so against the backdrop of unprecedented human migration. The concomitant cultural and social disruption throws up new questions around the nature and experience of religion, spirituality and the sacred. This paper explores these questions in the context of a Congolese choir called Elikya, which was established by a group of asylum seekers in Limerick city, Ireland, in 2001. In tracking the musical life of this choir over the last decade and a half, including two musical recordings and numerous liturgical, religious and secular performances, it suggests that the sonic world of the choir both performs and transcends these descriptors. Using a three-fold model of context, content and intent, the paper concludes that musical experiences such as those created by Elikya erode any easy divisions between the religious and the secular or the liturgical and the non-liturgical and provide sonic opportunities to encounter the sacred stranger in the untidy playground of creative chaos.

  19. Application of bacteriophages to reduce biofilms formed by hydrogen sulfide producing bacteria on surfaces in a rendering plant.

    Science.gov (United States)

    Gong, Chao; Jiang, Xiuping

    2015-08-01

    Hydrogen sulfide producing bacteria (SPB) in raw animal by-products are likely to grow and form biofilms in the rendering processing environments, resulting in the release of harmful hydrogen sulfide (H2S) gas. The objective of this study was to reduce SPB biofilms formed on different surfaces typically found in rendering plants by applying a bacteriophage cocktail. Using a 96-well microplate method, we determined that 3 SPB strains of Citrobacter freundii and Hafnia alvei are strong biofilm formers. Application of 9 bacteriophages (10(7) PFU/mL) from families of Siphoviridae and Myoviridae resulted in a 33%-70% reduction of biofilm formation by each SPB strain. On stainless steel and plastic templates, phage treatment (10(8) PFU/mL) reduced the attached cells of a mixed SPB culture (no biofilm) by 2.3 and 2.7 log CFU/cm(2) within 6 h at 30 °C, respectively, as compared with 2 and 1.5 log CFU/cm(2) reductions of SPB biofilms within 6 h at 30 °C. Phage treatment was also applied to indigenous SPB biofilms formed on the environmental surface, stainless steel, high-density polyethylene plastic, and rubber templates in a rendering plant. With phage treatment (10(9) PFU/mL), SPB biofilms were reduced by 0.7-1.4, 0.3-0.6, and 0.2-0.6 log CFU/cm(2) in spring, summer, and fall trials, respectively. Our study demonstrated that bacteriophages could effectively reduce the selected SPB strains either attached to or in formed biofilms on various surfaces and could to some extent reduce the indigenous SPB biofilms on the surfaces in the rendering environment.

  20. Unevenness of Sliding Surface of Overhead Rigid Conductor Lines and Method for Reducing Unevenness

    Science.gov (United States)

    Aboshi, Mitsuo; Shimizu, Masashi

    Rigid conductor lines are used in many subways, because the use of such conductor lines reduces the risk of accidents and because less space is required for their installation. However, as the unevenness of the sliding surface of the rigid conductor lines significantly influences the fluctuations in the contact force between pantographs and contact lines, it is necessary to decrease the unevenness at the construction as well as the maintenance stages. In order to investigate the installation accuracy of overhead rigid conductor lines, we have developed a device that accurately and continuously measures the unevenness of the sliding surface. By using this measuring device, we have confirmed that the unevenness of the sliding surface depends on various factors such as the sag between the support points, the deformation of the aluminum base or the conductive rail in the case of a long wavelength, the slight sagging unevenness between the bolts of the long ear, the undulating wear etc. This paper describes the actual unevenness conditions and the technical methods for decreasing the unevenness of the sliding surface of overhead rigid conductor lines.

  1. Osteopontin Reduces the Adhesion Force of Dental Bacteria Without Blocking Bacterial Cell Surface Glycoconjugates

    DEFF Research Database (Denmark)

    Kristensen, Mathilde Frost; Zeng, Guanghong; Neu, Thomas R.

    2017-01-01

    . paracasei, and lectins VGA and WGA to S. mitis. Immobilized bacteria were incubated with these lectins in the presence and absence of OPN. For each combination, 12 confocal images were acquired with fixed microscope settings, and average fluorescence intensities were determined. Experiments were performed......The bovine milk protein osteopontin (OPN) has been shown to reduce the adhesion of oral bacteria to saliva-coated surfaces, which reduces biofilm formation and may contribute to caries control. We now quantified the effect of OPN (Lacprodan OPN-10) treatment on the adhesion force of Lactobacillus...... and after OPN treatment. Adhesion energy was found to be reduced by 94% for L. paracasei and 61% for A. naeslundii (pbacteria was screened. Lectins BanLec, ConA, VGA and WGA bound well to A. naeslundii, lectins ABA and HPA to L...

  2. Reactivity of a reduced metal oxide surface: hydrogen, water and carbon monoxide adsorption on oxygen defective rutile TiO 2( 1 1 0 )

    Science.gov (United States)

    Menetrey, M.; Markovits, A.; Minot, C.

    2003-02-01

    The reactivity at reduced surface differs from that on the stoichiometric perfect surfaces. This does not originate uniquely from the modification of the coordination; electron count also is determining. The general trend is a decrease of the heat of adsorption on the metal cations. The reactivity decreases at sites in the vicinity of the defects due to the reduction induced by the O vacancies. At the defect site the decrease is less pronounced for H, H 2, CO and molecular H 2O. In the case of H 2O dissociative adsorption, the defect site is more reactive than the perfect surface. Thus, a hydration converting the defective-reduced TiO 2 to the hydrogenated non-defective-reduced surface is easy. The resulting structure possesses surface hydroxyl groups. It is probably the easiest way to form the hydrogenated non-defective surface. On TiO 2, the defective surface requires very anhydrous conditions.

  3. Isolation and dispersion of reduced metal particles using the surface dipole moment of F-terminated diamond electrodes

    Energy Technology Data Exchange (ETDEWEB)

    Miyamoto, M.; Tanaka, Y.; Furuta, M. [Department of Chemistry and Earth Sciences, School of Science, Yamaguchi University, 1677-1 Yoshida, Yamaguchi-shi, Yamaguchi 753-8512 (Japan); Kondo, T. [Department of Industrial Chemistry, Faculty of Engineering, Tokyo University of Science, 1-3 Kagurazaka, Shinjuku-ku, Tokyo 162-8601 (Japan); Fujishima, A. [Kanagawa Advanced Science and Technology (KAST), 3-2-1, Sakato, Takastu-ku, Kawasaki-shi, Kanagawa 213-0012 (Japan); Honda, K. [Department of Chemistry and Earth Sciences, School of Science, Yamaguchi University, 1677-1 Yoshida, Yamaguchi-shi, Yamaguchi 753-8512 (Japan)], E-mail: khonda@yamaguchi-u.ac.jp

    2009-04-30

    Cu particles that have been reductively generated at the oxidized surface of a boron-doped diamond electrode (O-BDD) can be removed from the electrode's surface by the repulsive electrostatic force of the surface dipole moment during a potential cycle of a solution of Cu{sup 2+} ions. The objective of this study was to isolate various metal particles other than Cu by use of a fluorine-terminated BDD surface (F-BDD) with a stronger surface dipole moment than O-BDD, and to clarify the mechanism of the metal particles' separation from the electrode. During the potential cycle treatment of Cu{sup 2+} ions using F-BDD, the reionization of the reduced Cu could be suppressed in the presence of dissolved oxygen, and the Cu particles were separated from the electrode surface as CuO. A similar result was seen with O-BDD. The degree of separation of the Cu particles could be drastically enhanced by raising the upper potential limit in the potential cycle from +0.2 to +0.8 V. By setting the upper potential to a potential greater than the metal-metal oxide equilibrium line in the potential-pH equilibrium diagram of the Cu-water system (Pourbaix Diagram), oxidation of the reduced metal surface by reaction with dissolved oxygen could be accelerated and the surface of metal particles could be insulated. The Cu particles were forced from the BDD surface by the electrostatic repulsion from the surface dipole moment of F-BDD. Also, it turned out that the physical adsorption of chloride ions (Cl{sup -}) on the electrode surface intensified the electrostatic repulsive force between the F- or O-BDD surface and the metal particles, and thus increased the degree of the metal particles' separation. For Zn with a metal-metal oxide equilibrium potential of approximately -0.8 V at pH 7, complete separation of the Zn particles was achieved with F-BDD by setting the upper potential limit to +0.8 V (vs. Ag/AgCl), decreasing the Zn{sup 2+} concentration (1/10 that of Cu{sup 2

  4. Alloying Au surface with Pd reduces the intrinsic activity in catalyzing CO oxidation

    KAUST Repository

    Qian, Kun

    2016-03-30

    © 2016. Various Au-Pd/SiO2 catalysts with a fixed Au loading but different Au:Pd molar ratios were prepared via deposition-precipitation method followed by H2 reduction. The structures were characterized and the catalytic activities in CO oxidation were evaluated. The formation of Au-Pd alloy particles was identified. The Au-Pd alloy particles exhibit enhanced dispersions on SiO2 than Au particles. Charge transfer from Pd to Au within Au-Pd alloy particles. Isolated Pd atoms dominate the surface of Au-Pd alloy particles with large Au:Pd molar ratios while contiguous Pd atoms dominate the surface of Au-Pd alloy particles with small Au:Pd molar ratios. Few synergetic effect of Au-Pd alloy occurs on catalyzing CO oxidation under employed reaction conditions. Alloying Au with Pd reduces the intrinsic activity in catalyzing CO oxidation, and contiguous Pd atoms on the Au-Pd alloy particles are capable of catalyzing CO oxidation while isolated Pd atoms are not. These results advance the fundamental understandings of Au-Pd alloy surfaces in catalyzing CO oxidation.

  5. Reducing dissolved inorganic nitrogen in surface runoff water from sugarcane production systems.

    Science.gov (United States)

    Webster, A J; Bartley, R; Armour, J D; Brodie, J E; Thorburn, P J

    2012-01-01

    Nitrogen (N) lost from farms, especially as the highly bioavailable dissolved inorganic form, may be damaging Australia's Great Barrier Reef (GBR). As sugarcane is the dominant cropping system in GBR catchments, its N management practises are coming under increasing scrutiny. This study measured dissolved inorganic N lost in surface runoff water and sugarcane productivity over 3 years. The experiment compared the conventional fertiliser N application rate to sugarcane (average 180kg N/ha/year) and a rate based on replacing N exported in the previous crop (average 94kg N/ha/year). Dissolved inorganic N losses in surface water were 72%, 48% and 66% lower in the three monitored years in the reduced N fertiliser treatment. There was no significant difference in sugarcane yield between the two fertiliser N treatments, nor any treatment difference in soil mineral N - both of these results are indicators of the sustainability of the lower fertiliser N applications. Copyright © 2012 Elsevier Ltd. All rights reserved.

  6. Boiling heat transfer to LN2 and LH2 - Influence of surface orientation and reduced body forces

    Science.gov (United States)

    Merte, H., Jr.; Oker, E.; Littles, J. W.

    1973-01-01

    The quantitative determination of the influence of heater surface orientation and gravity on nucleate pool boiling of liquid nitrogen and liquid hydrogen is described. A transient calorimeter technique, well suited for obtaining pool boiling data under reduced gravity and used earlier by Clark and Merte (1963), was employed after being adapted to flat a surface whose orientation could be varied. The obtained determination results are reviewed.

  7. Segurança com brinquedos de parques infantis: uma introdução ao problema Seguridad con juegos de parques infantiles: una introducción al problema Playground safety: an introduction to the problem

    Directory of Open Access Journals (Sweden)

    Maria de Jesus C. S. Harada

    2003-06-01

    Full Text Available A finalidade deste estudo é abordar temática pouco explorada na literatura nacional relativa à prevenção de acidentes relacionados ao uso de brinquedos de parques infantis. Nos Estados Unidos da América, estima-se que, anualmente, ocorrem mais de 200.000 acidentes com crianças, em parques infantis. Além de discutir esse problema, apresentamos algumas recomendações gerais sobre segurança nesses locais e a reflexão da necessidade de alertar e educar a sociedade sobre a importância da prevenção.El objetivo de este estudio es abordar un tema poco explotado en la literatura nacional acerca de la prevención de accidentes relacionados con el uso de juegos en parques infantiles. En los Estados Unidos de Norte América se estima que anualmente ocurren más de 200.000 accidentes con niños en parques infantiles. Además de discutir este problema, presentamos algunas recomendaciones generales sobre la seguridad en estos locales y la necesidad de alertar y educar a la sociedad sobre la importancia de la prevención.This study aims to approach the theme of accident prevention in relation to the use of playground toys, which is little explored in national literature. It is estimated that, annually, more than 200,000 accidents with children happen in playgrounds in the United States of America. Besides discussing this problem, we present some general recommendations about safety in these places and a reflection on the need to alert and educate society about the importance of prevention.

  8. Surface conditioning with Escherichia coli cell wall components can reduce biofilm formation by decreasing initial adhesion

    Directory of Open Access Journals (Sweden)

    Luciana C. Gomes

    2017-07-01

    Full Text Available Bacterial adhesion and biofilm formation on food processing surfaces pose major risks to human health. Non-efficient cleaning of equipment surfaces and piping can act as a conditioning layer that affects the development of a new biofilm post-disinfection. We have previously shown that surface conditioning with cell extracts could reduce biofilm formation. In the present work, we hypothesized that E. coli cell wall components could be implicated in this phenomena and therefore mannose, myristic acid and palmitic acid were tested as conditioning agents. To evaluate the effect of surface conditioning and flow topology on biofilm formation, assays were performed in agitated 96-well microtiter plates and in a parallel plate flow chamber (PPFC, both operated at the same average wall shear stress (0.07 Pa as determined by computational fluid dynamics (CFD. It was observed that when the 96-well microtiter plate and the PPFC were used to form biofilms at the same shear stress, similar results were obtained. This shows that the referred hydrodynamic feature may be a good scale-up parameter from high-throughput platforms to larger scale flow cell systems as the PPFC used in this study. Mannose did not have any effect on E. coli biofilm formation, but myristic and palmitic acid inhibited biofilm development by decreasing cell adhesion (in about 50%. These results support the idea that in food processing equipment where biofilm formation is not critical below a certain threshold, bacterial lysis and adsorption of cell components to the surface may reduce biofilm buildup and extend the operational time.

  9. Engineering of dendrimer surfaces to enhance transepithelial transport and reduce cytotoxicity.

    Science.gov (United States)

    Jevprasesphant, Rachaneekorn; Penny, Jeffrey; Attwood, David; McKeown, Neil B; D'Emanuele, Antony

    2003-10-01

    To evaluate the cytotoxicity, permeation, and transport mechanisms of PAMAM dendrimers and surface-modified cationic PAMAM dendrimers using monolayers of the human colon adenocarcinoma cell line, Caco-2. Cytotoxicity was determined using the MTT assay. The effect of dendrimers on monolayer integrity was determined from measurements of transepithelial electrical resistance (TEER) and [14C]mannitol apparent permeability coefficient (Papp). The Papp of dendrimers through monolayers was measured in both the apical (A)-to-basolateral (B) and B --> A directions at 4 degrees C and 37 degrees C and also in the presence and absence of ethylenediamine tetraacetic acid (EDTA) and colchicine. The cytotoxicity and permeation of dendrimers increased with both concentration and generation. The cytotoxicity of cationic dendrimers (G2, G3, G4) was greater than that of anionic dendrimers (G2.5, G3.5) but was reduced by conjugation with lauroyl chloride: the least cytotoxic conjugates were those with six attached lauroyl chains. At 37 degrees C the Papp of cationic dendrimers was higher than that of anionic dendrimers and, in general, increased with the number of attached lipid chains. Cationic dendrimers decreased TEER and significantly increased the Papp of mannitol. Modified dendrimers also reduced TEER and caused a more marked increase in the Papp of mannitol. The Papp values of dendrimers and modified dendrimers were higher in the presence of EDTA, lower in the presence of colchicine, and lower at 4 degrees C than at 37 degrees C. The properties of dendrimers may be significantly modified by surface engineering. Conjugation of cationic PAMAM dendrimers with lauroyl chloride decreased their cytotoxicity and increased their permeation through Caco-2 cell monolayers. Both PAMAM dendrimers and lauroyl-PAMAM dendrimer conjugates can cross epithelial monolayers by paracellular and transcellular pathways.

  10. Washed Away!

    Science.gov (United States)

    Cheek, Kim A.

    2013-01-01

    Earth's surface is constantly changing. Weathering, erosion, and deposition break down Earth materials, transport those materials, and place them in new locations. Children see evidence of these processes all around them. The sidewalk or playground surface cracks and has plants growing in it. Pieces of a rock wall or the sides of a building…

  11. SURFACE PROPERTIES OF ELECTROCHEMICALLY REDUCED ...

    African Journals Online (AJOL)

    DJFLEX

    A viscose rayon based activated carbon cloth (ACC) was electrochemically reduced ..... bath of liquid nitrogen at a temperature of 77 K. ... that above 59,400 c/g extent of oxidation, the ..... ACC react with aldehyde groups to produce ether.

  12. Evaluating the Performance of a Surface Barrier on Reducing Soil-Water Flow

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Z. F.; Strickland, Christopher E.; Field, Jim G.; Parker, Danny L.; Clayton, Ray E.

    2012-08-31

    One of the most common effective techniques for contaminant remediation in the vadose zone is to use a surface barrier to reduce or eliminate soil-water flow to reduce the contaminant flux to the underlying groundwater. Confirming the reduction of the soil-water flux rate is challenging because of the difficulty of determining the very low soil-water flux beneath the barrier. We propose a hydraulic-conductivity factor, fK, as a conservative indicator for quantifying the reduction of soil-water flow. The factor can be calculated using the measured soil-water content or pressure but does not require the knowledge of the saturated hydraulic conductivity or the hydraulic gradient. The formulas were tested by comparing with changes in hydraulic conductivity, K, from a drainage experiment. The pressure-based formula was further applied to evaluate the performance of the interim surface barrier at T Tank Farm on Hanford Site. Three years after barrier emplacement, the hydraulic conductivity decreased by a factor between 3.8 and 13.0 at the 1-, 2- and 5-m depths. The difference between the conductivity-reduction factor and the flux-rate-reduction factor, fq, was quantified with a numerical simulation. With the calculated fK, the numerically determined fK/fq ratio, and the assumed pre-barrier soil-water flux rate of 100 mm yr-1, the estimated soil-water flux rate 3 years after barrier emplacement was no more than 8.5 mm yr-1 at or above the 5-m depth.

  13. Synthesis and characterization of a lubricin mimic (mLub) to reduce friction and adhesion on the articular cartilage surface.

    Science.gov (United States)

    Lawrence, Alexandra; Xu, Xin; Bible, Melissa D; Calve, Sarah; Neu, Corey P; Panitch, Alyssa

    2015-12-01

    The lubricating proteoglycan, lubricin, facilitates the remarkable low friction and wear properties of articular cartilage in the synovial joints of the body. Lubricin lines the joint surfaces and plays a protective role as a boundary lubricant in sliding contact; decreased expression of lubricin is associated with cartilage degradation and the pathogenesis of osteoarthritis. An unmet need for early osteoarthritis treatment is the development of therapeutic molecules that mimic lubricin function and yet are also resistant to enzymatic degradation common in the damaged joint. Here, we engineered a lubricin mimic (mLub) that is less susceptible to enzymatic degradation and binds to the articular surface to reduce friction. mLub was synthesized using a chondroitin sulfate backbone with type II collagen and hyaluronic acid (HA) binding peptides to promote interaction with the articular surface and synovial fluid constituents. In vitro and in vivo characterization confirmed the binding ability of mLub to isolated type II collagen and HA, and to the cartilage surface. Following trypsin treatment to the cartilage surface, application of mLub, in combination with purified or commercially available hyaluronan, reduced the coefficient of friction, and adhesion, to control levels as assessed over macro-to micro-scales by rheometry and atomic force microscopy. In vivo studies demonstrate an mLub residency time of less than 1 week. Enhanced lubrication by mLub reduces surface friction and adhesion, which may suppress the progression of degradation and cartilage loss in the joint. mLub therefore shows potential for treatment in early osteoarthritis following injury. Copyright © 2015 Elsevier Ltd. All rights reserved.

  14. Slippery liquid-infused porous surfaces fabricated on aluminum as a barrier to corrosion induced by sulfate reducing bacteria

    International Nuclear Information System (INIS)

    Wang, Peng; Lu, Zhou; Zhang, Dun

    2015-01-01

    Highlights: • Slippery liquid-infused porous surfaces (SLIPS) were fabricated over aluminum. • SLIPS depress the adherence of sulfate reducing bacteria in static seawater. • SLIPS inhibit the microbiological corrosion of aluminum in static seawater. • The possible microbiological corrosion protection mechanism of SLIPS is proposed. - Abstract: Microbiological corrosion induced by sulfate reducing bacteria (SRB) is one of the main threatens to the safety of marine structure. To reduce microbiological corrosion, slippery liquid infused porous surfaces (SLIPS) were designed and fabricated on aluminum substrate by constructing rough aluminum oxide layer, followed by fluorination of the rough layer and infiltration with lubricant. The as-fabricated SLIPS were characterized with wettability measurement, SEM and XPS. Their resistances to microbiological corrosion induced by SRB were evaluated with fluorescence microscopy and electrochemical measurement. It was demonstrated that they present high resistance to bacteria adherence and the resultant microbiological corrosion in static seawater

  15. Reduced recombination in a surface-sulfurized Cu(InGa)Se2 thin-film solar cell

    Science.gov (United States)

    Kim, Shinho; Nishinaga, Jiro; Kamikawa, Yukiko; Ishizuka, Shogo; Nagai, Takehiko; Koida, Takashi; Tampo, Hitoshi; Shibata, Hajime; Matsubara, Koji; Niki, Shigeru

    2018-05-01

    This study demonstrates surface sulfurization effects on Cu(InGa)Se2 (CIGSe) thin-film solar cells with a single back-graded band gap. Single back-graded CIGSe thin films were prepared via a three-stage process in a high-vacuum molecular beam epitaxial growth chamber and were subsequently annealed in a tube furnace under environmental conditions with H2S gas. After sulfurization, an ∼80- to ∼100-nm-thick CuIn(SSe)2 layer with significantly small Ga contents (CISSe:Ga) was formed on the CIGSe layer. The newly formed CISSe:Ga layer exhibited graded S contents from surface to bulk, thus resulting in a front-graded band gap. In addition, CISSe:Ga was covered with S-enriched CISSe region that was extended from the surface to a depth of a few nm and was depleted of Ga. A device with the sulfurized CIGSe showed reduced recombination at the buffer–absorber interface, in space-charge region and in bulk. Consequently, the open circuit voltage increased from 0.58 V (in the non-sulfurized case) to 0.66 V, and the conversion efficiency improved from 15.5 to 19.4%. This large improvement is caused by the front graded band gap at the surface and the hole-blocking barrier, which suppress recombination at the CdS/CISSe:Ga interface. In addition, sulfurization followed by KF post-deposition treatment (PDT) increased the efficiency to 20.1%. Compared to the untreated sulfurized device, the KF-PDT device delivered an increased carrier lifetime and reduced the recombination in bulk probably because the defects were passivated by the K, which penetrated into the bulk region.

  16. Understanding the Role of Wind in Reducing the Surface Mass Balance Estimates over East Antarctica

    Science.gov (United States)

    Das, I.; Scambos, T. A.; Koenig, L.; Creyts, T. T.; Bell, R. E.; van den Broeke, M. R.; Lenaerts, J.; Paden, J. D.

    2014-12-01

    Accurate quantification of surface snow-accumulation over Antarctica is important for mass balance estimates and climate studies based on ice core records. An improved estimate of surface mass balance must include the significant role near-surface wind plays in the sublimation and redistribution of snow across Antarctica. We have developed an empirical model based on airborne radar and lidar observations, and modeled surface mass balance and wind fields to produce a continent-wide prediction of wind-scour zones over Antarctica. These zones have zero to negative surface mass balance, are located over locally steep ice sheet areas (>0.002) and controlled by bedrock topography. The near-surface winds accelerate over these zones, eroding and sublimating the surface snow. This scouring results in numerous localized regions (≤ 200 km2) with reduced surface accumulation. Each year, tens of gigatons of snow on the Antarctic ice sheet are ablated by persistent near-surface katabatic winds over these wind-scour zones. Large uncertainties remain in the surface mass balance estimates over East Antarctica as climate models do not adequately represent the small-scale physical processes that lead to mass loss through sublimation or redistribution over the wind-scour zones. In this study, we integrate Operation IceBridge's snow radar over the Recovery Ice Stream with a series of ice core dielectric and depth-density profiles for improved surface mass balance estimates that reflect the mass loss over the wind-scour zones. Accurate surface mass balance estimates from snow radars require spatially variable depth-density profiles. Using an ensemble of firn cores, MODIS-derived surface snow grain size, modeled accumulation rates and surface temperatures from RACMO2, we assemble spatially variable depth-density profiles and use our mapping of snow density variations to estimate layer mass and net accumulation rates from snow radar layer data. Our study improves the quantification of

  17. Campylobacter jejuni cocultured with epithelial cells reduces surface capsular polysaccharide expression.

    LENUS (Irish Health Repository)

    Corcionivoschi, N

    2012-02-01

    The host cell environment can alter bacterial pathogenicity. We employed a combination of cellular and molecular techniques to study the expression of Campylobacter jejuni polysaccharides cocultured with HCT-8 epithelial cells. After two passages, the amount of membrane-bound high-molecular-weight polysaccharide was considerably reduced. Microarray profiling confirmed significant downregulation of capsular polysaccharide (CPS) locus genes. Experiments using conditioned media showed that sugar depletion occurred only when the bacterial and epithelial cells were cocultured. CPS depletion occurred when C. jejuni organisms were exposed to conditioned media from a different C. jejuni strain but not when exposed to conditioned media from other bacterial species. Proteinase K or heat treatment of conditioned media under coculture conditions abrogated the effect on the sugars, as did formaldehyde fixation and cycloheximide treatment of host cells or chloramphenicol treatment of the bacteria. However, sugar depletion was not affected in flagellar export (fliQ) and quorum-sensing (luxS) gene mutants. Passaged C. jejuni showed reduced invasiveness and increased serum sensitivity in vitro. C. jejuni alters its surface polysaccharides when cocultured with epithelial cells, suggesting the existence of a cross talk mechanism that modulates CPS expression during infection.

  18. High-risk human papillomavirus E7 expression reduces cell-surface MHC class I molecules and increases susceptibility to natural killer cells

    DEFF Research Database (Denmark)

    Bottley, G; Watherston, O G; Hiew, Y-L

    2007-01-01

    a role for E7 in tumour immune evasion. We show that knockdown of E7 expression in HPV16- and HPV18-transformed cervical carcinoma cells by RNA interference increased expression of major histocompatibility complex (MHC) class I at the cell surface and reduced susceptibility of these cells to natural...... killer (NK) cells. Tetracycline-regulated induction of HPV16 E7 resulted in reduced expression of cell surface MHC class I molecules and increased NK cell killing. Our results suggest that, for HPV-associated malignancies, reduced MHC class I expression is the result of an active immune evasion strategy...

  19. An investigation of the sensitivity of a land surface model to climate change using a reduced form model

    Energy Technology Data Exchange (ETDEWEB)

    Lynch, A.H.; McIlwaine, S. [PAOS/CIRES, Univ. of Colorado, Boulder, CO (United States); Beringer, J. [Inst. of Arctic Biology, Univ. of Alaska, Fairbanks (United States); Bonan, G.B. [National Center for Atmospheric Research, Boulder, CO (United States)

    2001-05-01

    In an illustration of a model evaluation methodology, a multivariate reduced form model is developed to evaluate the sensitivity of a land surface model to changes in atmospheric forcing. The reduced form model is constructed in terms of a set of ten integrative response metrics, including the timing of spring snow melt, sensible and latent heat fluxes in summer, and soil temperature. The responses are evaluated as a function of a selected set of six atmospheric forcing perturbations which are varied simultaneously, and hence each may be thought of as a six-dimensional response surface. The sensitivities of the land surface model are interdependent and in some cases illustrate a physically plausible feedback process. The important predictors of land surface response in a changing climate are the atmospheric temperature and downwelling longwave radiation. Scenarios characterized by warming and drying produce a large relative response compared to warm, moist scenarios. The insensitivity of the model to increases in precipitation and atmospheric humidity is expected to change in applications to coupled models, since these parameters are also strongly implicated, through the representation of clouds, in the simulation of both longwave and shortwave radiation. (orig.)

  20. Evaluation of modified stainless steel surfaces targeted to reduce biofilm formation by common milk sporeformers.

    Science.gov (United States)

    Jindal, Shivali; Anand, Sanjeev; Huang, Kang; Goddard, Julie; Metzger, Lloyd; Amamcharla, Jayendra

    2016-12-01

    The development of bacterial biofilms on stainless steel (SS) surfaces poses a great threat to the quality of milk and other dairy products as the biofilm-embedded bacteria can survive thermal processing. Established biofilms offer cleaning challenges because they are resistant to most of the regular cleaning protocols. Sporeforming thermoduric organisms entrapped within biofilm matrix can also form heat-resistant spores, and may result in a long-term persistent contamination. The main objective of this study was to evaluate the efficacy of different nonfouling coatings [AMC 18 (Advanced Materials Components Express, Lemont, PA), Dursan (SilcoTek Corporation, Bellefonte, PA), Ni-P-polytetrafluoroethylene (PTFE, Avtec Finishing Systems, New Hope, MN), and Lectrofluor 641 (General Magnaplate Corporation, Linden, NJ)] on SS plate heat exchanger surfaces, to resist the formation of bacterial biofilms. It was hypothesized that modified SS surfaces would promote a lesser amount of deposit buildup and bacterial adhesion as compared with the native SS surface. Vegetative cells of aerobic sporeformers, Geobacillus stearothermophilus (ATCC 15952), Bacillus licheniformis (ATCC 6634), and Bacillus sporothermodurans (DSM 10599), were used to study biofilm development on the modified and native SS surfaces. The adherence of these organisms, though influenced by surface energy and hydrophobicity, exhibited no apparent relation with surface roughness. The Ni-P-PTFE coating exhibited the least bacterial attachment and milk solid deposition, and hence, was the most resistant to biofilm formation. Scanning electron microscopy, which was used to visualize the extent of biofilm formation on modified and native SS surfaces, also revealed lower bacterial attachment on the Ni-P-PTFE as compared with the native SS surface. This study thus provides evidence of reduced biofilm formation on the modified SS surfaces. Copyright © 2016 American Dairy Science Association. Published by Elsevier

  1. Naval Reserve Force: Cost and Benefit Analysis of Reducing the Number of Naval Surface Reserve Force Operating Budget Holders

    National Research Council Canada - National Science Library

    Young, Eric

    1997-01-01

    .... This thesis examines one of Commander Naval Surface Reserve Force's initiatives for reducing the current number of Operating Budget holder's Comptroller Departments without sacrificing efficiency...

  2. H2S adsorption and decomposition on the gradually reduced α-Fe2O3(001) surface: A DFT study

    Science.gov (United States)

    Lin, Changfeng; Qin, Wu; Dong, Changqing

    2016-11-01

    Reduction of iron based desulfurizer occurs during hot gas desulfurization process, which will affect the interaction between H2S and the desulfurizer surface. In this work, a detailed adsorption behavior and dissociation mechanism of H2S on the perfect and reduced α-Fe2O3(001) surfaces, as well as the correlation between the interaction characteristic and reduction degree of iron oxide, have been studied by using periodic density functional theory (DFT) calculations. Results demonstrate that H2S firstly chemisorbs on surface at relatively higher oxidation state (reduction degree χ 33%. Reduction of iron oxide benefits the H2S adsorption. Further, dissociation processes of H2S via molecular and dissociative adsorption were investigated. Results show that after reduction of Fe2O3 into the oxidation state around FeO and Fe, the reduced surface exhibits very strong catalytic capacity for H2S decomposition into S species. Meanwhile, the overall dissociation process on all surfaces is exothermic. These results provide a fundamental understanding of reduction effect of iron oxide on the interaction mechanism between H2S and desulfurizer surface, and indicate that rational control of reduction degree of desulfurizer is essential for optimizing the hot gas desulfurization process.

  3. Effects of bulk charged impurities on the bulk and surface transport in three-dimensional topological insulators

    Energy Technology Data Exchange (ETDEWEB)

    Skinner, B.; Chen, T.; Shklovskii, B. I., E-mail: shklovsk@physics.spa.umn.edu [University of Minnesota, Fine Theoretical Physics Institute (United States)

    2013-09-15

    In the three-dimensional topological insulator (TI), the physics of doped semiconductors exists literally side-by-side with the physics of ultrarelativistic Dirac fermions. This unusual pairing creates a novel playground for studying the interplay between disorder and electronic transport. In this mini-review, we focus on the disorder caused by the three-dimensionally distributed charged impurities that are ubiquitous in TIs, and we outline the effects it has on both the bulk and surface transport in TIs. We present self-consistent theories for Coulomb screening both in the bulk and at the surface, discuss the magnitude of the disorder potential in each case, and present results for the conductivity. In the bulk, where the band gap leads to thermally activated transport, we show how disorder leads to a smaller-than-expected activation energy that gives way to variable-range hopping at low temperatures. We confirm this enhanced conductivity with numerical simulations that also allow us to explore different degrees of impurity compensation. For the surface, where the TI has gapless Dirac modes, we present a theory of disorder and screening of deep impurities, and we calculate the corresponding zero-temperature conductivity. We also comment on the growth of the disorder potential in passing from the surface of the TI into the bulk. Finally, we discuss how the presence of a gap at the Dirac point, introduced by some source of time-reversal symmetry breaking, affects the disorder potential at the surface and the mid-gap density of states.

  4. Effects of bulk charged impurities on the bulk and surface transport in three-dimensional topological insulators

    International Nuclear Information System (INIS)

    Skinner, B.; Chen, T.; Shklovskii, B. I.

    2013-01-01

    In the three-dimensional topological insulator (TI), the physics of doped semiconductors exists literally side-by-side with the physics of ultrarelativistic Dirac fermions. This unusual pairing creates a novel playground for studying the interplay between disorder and electronic transport. In this mini-review, we focus on the disorder caused by the three-dimensionally distributed charged impurities that are ubiquitous in TIs, and we outline the effects it has on both the bulk and surface transport in TIs. We present self-consistent theories for Coulomb screening both in the bulk and at the surface, discuss the magnitude of the disorder potential in each case, and present results for the conductivity. In the bulk, where the band gap leads to thermally activated transport, we show how disorder leads to a smaller-than-expected activation energy that gives way to variable-range hopping at low temperatures. We confirm this enhanced conductivity with numerical simulations that also allow us to explore different degrees of impurity compensation. For the surface, where the TI has gapless Dirac modes, we present a theory of disorder and screening of deep impurities, and we calculate the corresponding zero-temperature conductivity. We also comment on the growth of the disorder potential in passing from the surface of the TI into the bulk. Finally, we discuss how the presence of a gap at the Dirac point, introduced by some source of time-reversal symmetry breaking, affects the disorder potential at the surface and the mid-gap density of states

  5. Surface characteristics of coated polyester fabric with reduced graphene oxide and polypyrrole

    Energy Technology Data Exchange (ETDEWEB)

    Berendjchi, Amirhosein [Department of Textile Engineering, Science and Research Branch, Islamic Azad University, Tehran (Iran, Islamic Republic of); Khajavi, Ramin, E-mail: khajavi@azad.ac.ir [Nano Technology Research Center, South Tehran Branch, Islamic Azad University, Tehran (Iran, Islamic Republic of); Yousefi, Ali Akbar [Faculty of Polymer Processing, Iran Polymer and Petrochemical Institute, Tehran (Iran, Islamic Republic of); Yazdanshenas, Mohammad Esmail [Department of Textile Engineering, Yazd Branch, Islamic Azad University, Yazd (Iran, Islamic Republic of)

    2016-03-30

    Graphical abstract: - Highlights: • PET in form of film or membrane is hydrophobic and its wetting behavior follows the Wenzel wetting theory. In the form of textile materials it shows hydrophilicity. • rGO coated PET fabric shows hydrophobicity and its wetting behavior places between Wenzel and Cassie–Baxter models. • PET coated fabric by PPy shows superhydrophobicity and its wetting behavior is consistence with Cassie–Baxter model. • Due to oxidation of the rGO during in situ synthesis of PPy the rGO–PPy coated PET shows hydrophilicity. - Abstract: In this study, the influence of coating polyethylene terephthalate (PET) fabric with reduced graphene oxide (rGO) and polypyrrole (PPy), individually or in combination (rGO–PPy), on surface chemistry and roughness (focusing on wetting behavior), were analyzed systematically. Characterization was carried out by observing the topography (atomic force microscopy – AFM) and stating surface analysis (X-ray photoelectron spectroscopy – XPS), contact angles (goniometry), water shedding angles, and surface energy values of the samples. The results showed that the contact angles of pristine (uncoated), GO and rGO–PPy coated samples were 0°, while it was 92°, 123° and 151° for hot pressed (2nd pristine sample), rGO and PPy samples, respectively. A zero contact angle for PET sample was due to its wicking ability. Results were interpreted with Young, Wenzel and Cassie Baxter equations. It was found that PPy coated samples were consistent with Cassie–Baxter equation, while rGO placed between Wenzel and Cassie–Baxter wetting models.

  6. Estimating costs and potentials of different methods to reduce the Swedish phosphorus load from agriculture to surface water.

    Science.gov (United States)

    Malmaeus, J M; Karlsson, O M

    2010-01-01

    This paper reviews 17 measures to reduce phosphorus leakage from Swedish agriculture to surface waters. Our aim is to evaluate the possible contribution from agriculture to achieve environmental goals including the Baltic Sea Action Plan. Using a regional approach integrating the variability in field specific characteristics, typical costs and national potential for the included measures may be estimated without identifying, e.g., suitable individual fields for implementation. The result may be helpful to select suitable measures but may also influence the design of environmental targets before they are determined. We find that the cheapest measures are reduced phosphorus content in animal food and fertilizer application supervision in pig farms, both measures with annual potentials of around 50t each, and costs of euro7 to euro11 kg(-1)yr(-1). The total potential of the listed measures is an annual phosphorus reduction to surface waters of 242t. If the most expensive measures are excluded (>euro1000 kg(-1)yr(-1)) and including retention in lakes the phosphorus transport to the sea could be reduced by 165 t yr(-1). This amount can be compared with the Swedish commitment in the Baltic Sea Action Plan (BSAP) to reduce input to the Baltic Proper by 290 t yr(-1).

  7. Rye cover crop increases earthworm populations and reduces losses of broadcast, fall-applied, fertilizers in surface runoff

    Science.gov (United States)

    Corn (Zea mays L.) silage and soybean [Glycine max (L.) Merr.] rotations in the US Upper Midwest leave minimal amounts of surface residues, which can contribute to soil degradation and a reduction in water quality. Planting cover crops after harvest can reduce these concerns, but their effectiveness...

  8. Free surface modelling with two-fluid model and reduced numerical diffusion of the interface

    International Nuclear Information System (INIS)

    Strubelj, Luka; Tiselj, Izrok

    2008-01-01

    Full text of publication follows: The free surface flows are successfully modelled with one of existing free surface models, such as: level set method, volume of fluid method (with/without surface reconstruction), front tracking, two-fluid model (two momentum equations) with modified interphase force and others. The main disadvantage of two-fluid model used for simulations of free surface flows is numerical diffusion of the interface, which can be significantly reduced using the method presented in this paper. Several techniques for reduction of numerical diffusion of the interface have been implemented in the volume of fluid model and are based on modified numerical schemes for advection of volume fraction near the interface. The same approach could be used also for two-fluid method, but according to our experience more successful reduction of numerical diffusion of the interface can be achieved with conservative level set method. Within the conservative level set method, continuity equation for volume fraction is solved and after that the numerical diffusion of the interface is reduced in such a way that the thickness of the interface is kept constant during the simulation. Reduction of the interface diffusion can be also called interface sharpening. In present paper the two-fluid model with interface sharpening is validated on Rayleigh-Taylor instability. Under assumptions of isothermal and incompressible flow of two immiscible fluids, we simulated a system with the fluid of higher density located above the fluid of smaller density in two dimensions. Due to gravity in the system, fluid with higher density moves below the fluid with smaller density. Initial condition is not a flat interface between the fluids, but a sine wave with small amplitude, which develops into a mushroom-like structure. Mushroom-like structure in simulation of Rayleigh-Taylor instability later develops to small droplets as result of numerical dispersion of interface (interface sharpening

  9. Reducing surface tension in endodontic chelator solutions has no effect on their ability to remove calcium from instrumented root canals.

    Science.gov (United States)

    Zehnder, Matthias; Schicht, Olivier; Sener, Beatrice; Schmidlin, Patrick

    2005-08-01

    The aim of this study was to evaluate the effect of reducing surface tension in endodontic chelator solutions on their ability to remove calcium from instrumented root canals. Aqueous solutions containing 15.5% EDTA, 10% citric acid, or 18% 1- hydroxyethylidene-1, 1-bisphosphonate (HEBP) were prepared with and without 1% (wt/wt) polysorbate (Tween) 80 and 9% propylene glycol. Surface tension in these solutions was measured using the Wilhelmy method. Sixty-four extracted, single-rooted human teeth of similar length were instrumented and irrigated with a 1% sodium hypochlorite solution and then randomly assigned (n = 8 per group) to receive a final one-minute rinse with 5 ml of test solutions, water, or the pure aqueous Tween/propylene glycol solution. Calcium concentration in eluates was measured using atomic absorption spectrometry. Incorporation of wetting agents resulted in a reduction of surface tension values by approximately 50% in all tested solutions. However, none of the solutions with reduced surface tension chelated more calcium from canals than their pure counterparts (p > 0.05).

  10. Reducing surface roughness by optimising the turning parameters

    Directory of Open Access Journals (Sweden)

    Senthil Kumar, K.

    2013-08-01

    Full Text Available Modern manufacturers worldwide look for the cheapest quality-manufactured machined components to compete in the market. Good surface quality is desired for the proper functioning of the parts produced. The surface quality is influenced by the cutting speed, feed rate, depth of cut, and many other parameters. In this paper, the Taguchi method a powerful tool to design optimisation for quality is used to find the optimal machining parameters for the turning operation. An orthogonal array, the signal-to-noise (S/N ratio, and the analysis of variance (ANOVA are employed to investigate the machining characteristics of super duplex stainless steel bars using uncoated carbide cutting tools. The effect of machining parameters on surface roughness was discovered. Confirmation tests were conducted at optimal conditions to compare the experimental results with the predicted values.

  11. Gold Cluster Diffusion Kinetics on Stoichiometric and Reduced Surfaces of Rutile TiO 2 (110)

    Energy Technology Data Exchange (ETDEWEB)

    Goldman, Nir; Browning, Nigel D.

    2011-06-16

    Gold clusters on rutile TiO2 are known to serve as efficient oxidation catalysts for pollutants and environmental contaminants. However, the mechanism by which highly mobile small clusters migrate and aggregate into larger species relevant to gold’s catalytic activity remains unresolved. We report herein on ab initio simulations of the diffusion of atomic gold clusters up to the trimer on rutile TiO2(110) surfaces. We show that, on the stoichiometric surface, both the dimer and the trimer can exhibit relatively low surface mobility due to high energetic barriers for diffusion out of their energetic minima coupled with low barriers for the reverse motion. On the reduced surface, these clusters can diffuse relatively quickly between energetic minima within the oxygen vacancy site due to the large degree of vibrational entropy in their transition states. Our computed diffusion times provide a point of comparison for future experiments and will aid in development of models of gold cluster island sintering.

  12. Fabrication of friction-reducing texture surface by selective laser melting of ink-printed (SLM-IP) copper (Cu) nanoparticles(NPs)

    Science.gov (United States)

    Wang, Xinjian; Liu, Junyan; Wang, Yang; Fu, Yanan

    2017-02-01

    This paper reports a process of selective laser melting of ink-printed (SLM-IP) copper (Cu) nanoparticles(NPs) for the fabrication of full dense Cu friction-reducing texture on the metallic surface in ambient condition. This technique synthesizes pure Cu by chemical reduction route using an organic solvent during laser melting in the atmosphere environment, and provides a flexible additive manufacture approach to form complex friction-reduction texture on the metallic surface. Microtextures of ring and disc arrays have been fabricated on the stainless steel surface by SLM-IP Cu NPs. The friction coefficient has been measured under the lubricating condition of the oil. Disc texture surface (DTS) has a relatively low friction coefficient compared with ring texture surface (RTS), Cu film surface (Cu-FS) and the untreated substrate. The study suggests a further research on SLM-IP approach for complex microstructure or texture manufacturing, possibly realizing its advantage of flexibility.

  13. Effect of surface Fe-S hybrid structure on the activity of the perfect and reduced α-Fe2O3(001) for chemical looping combustion

    Science.gov (United States)

    Xiao, Xianbin; Qin, Wu; Wang, Jianye; Li, Junhao; Dong, Changqing

    2018-05-01

    Sulfurization of the gradually reduced Fe2O3 surfaces is inevitable while Fe2O3 is used as an oxygen carrier (OC) for coal chemical looping combustion (CLC), which will result in formation of Fe-S hybrid structure on the surfaces. The Fe-S hybrid structure will directly alter the reactivity of the surfaces. Therefore, detailed properties of Fe-S hybrid structure over the perfect and reduced Fe2O3(001) surfaces, and its effect on the interfacial interactions, including CO oxidization and decomposition on the surfaces, were investigated by using density functional theory (DFT) calculations. The S atom prefers to chemically bind to Fe site with electron transfer from the surfaces to the S atom, and a deeper reduction of Fe2O3(001) leads to an increasing interaction between S and Fe. The formation of Fe-S hybrid structure alters the electronic properties of the gradually reduced Fe2O3(001) surfaces, promoting CO oxidation on the surfaces ranging from Fe2O3 to FeO, but depressing carbon deposition on the surfaces ranging from FeO to Fe. The sulfurized FeO acts as a watershed to realize relatively high CO oxidation rate and low carbon deposition. Results provided a fundamental understanding for controlling and optimizing the CLC processes.

  14. Multicenter evaluation of a new closed system drug-transfer device in reducing surface contamination by antineoplastic hazardous drugs.

    Science.gov (United States)

    Bartel, Sylvia B; Tyler, Timothy G; Power, Luci A

    2018-02-15

    Results of a study to evaluate the effectiveness of a recently introduced closed system drug-transfer device (CSTD) in reducing surface contamination during compounding and simulated administration of antineoplastic hazardous drugs (AHDs) are reported. Wipe samples were collected from 6 predetermined surfaces in compounding and infusion areas of 13 U.S. cancer centers to establish preexisting levels of surface contamination by 2 marker AHDs (cyclophosphamide and fluorouracil). Stainless steel templates were placed over the 6 previously sampled surfaces, and the marker drugs were compounded and infused per a specific protocol using all components of the CSTD. Wipe samples were collected from the templates after completion of tasks and analyzed for both marker AHDs. Aggregated results of wipe sampling to detect preexisting contamination at the 13 study sites showed that overall, 66.7% of samples (104 of 156) had detectable levels of at least 1 marker AHD; subsequent testing after CSTD use per protocol found a sample contamination rate of 5.8% (9 of 156 samples). In the administration areas alone, the rate of preexisting contamination was 78% (61 of 78 samples); with use of the CSTD protocol, the contamination rate was 2.6%. Twenty-six participants rated the CSTD for ease of use, with 100% indicating that they were satisfied or extremely satisfied. A study involving a rigorous protocol and 13 cancer centers across the United States demonstrated that the CSTD reduced surface contamination by cyclophosphamide and fluorouracil during compounding and simulated administration. Participants reported that the CSTD was easy to use. Copyright © 2018 by the American Society of Health-System Pharmacists, Inc. All rights reserved.

  15. Effect of Reduced Phosphoric Acid Pre-etching Times 
on Enamel Surface Characteristics and Shear Fatigue Strength Using Universal Adhesives.

    Science.gov (United States)

    Tsujimoto, Akimasa; Fischer, Nicholas; Barkmeier, Wayne; Baruth, Andrew; Takamizawa, Toshiki; Latta, Mark; Miyazaki, Masashi

    2017-01-01

    To examine the effect of reduced phosphoric acid pre-etching times on enamel fatigue bond strength of universal adhesives and surface characteristics by using atomic force microscopy (AFM). Three universal adhesives were used in this study (Clearfil Universal Bond [C], G-Premio Bond [GP], Scotchbond Universal Adhesive [SU]). Four pre-etching groups were employed: enamel pre-etched with phosphoric acid and immediately rinsed with an air-water spray, and enamel pre-etched with phosphoric acid for 5, 10, or 15 s. Ground enamel was used as the control group. For the initial bond strength test, 15 specimens per etching group for each adhesive were used. For the shear fatigue test, 20 specimens per etching group for each adhesive were loaded using a sine wave at a frequency of 20 Hz for 50,000 cycles or until failure occurred. Initial shear bond strengths and fatigue shear strengths of composite adhesively bonded to ground and pre-etched enamel were determined. AFM observations of ground and pre-etched enamel were also conducted, and surface roughness as well as surface area were evaluated. The initial shear bond strengths and fatigue shear strengths of the universal adhesives in the pre-etched groups were significantly higher than those of the control group, and were not influenced by the pre-etching time. Significantly higher surface roughness and surface area of enamel surfaces in pre-etched groups were observed compared with those in the control group. While the surface area was not significantly influenced by etching time, surface roughness of the enamel surfaces in the pre-etched groups significantly increased with pre-etching time. The results of this in vitro study suggest that reduced phosphoric acid pre-etching times do not impair the fatigue bond strength of universal adhesives. Although fatigue bond strength and surface area were not influenced by phosphoric-acid etching times, surface roughness increased with increasing etching time.

  16. Acrolein coupling on reduced TiO 2(1 1 0): The effect of surface oxidation and the role of subsurface defects

    Science.gov (United States)

    Benz, Lauren; Haubrich, Jan; Quiller, Ryan G.; Friend, Cynthia M.

    2009-04-01

    Reactions of acrolein, water, and oxygen with the vacuum-reduced surface of TiO 2(1 1 0) are reported in a temperature programmed reaction study of the interaction of an aldehydic pollutant with a reducible metal oxide. A total of 25% of the acrolein that binds to the surface is converted to products. Notably, carbon-carbon coupling occurs with 86% selectivity for formation of C 6 products: C 6H 8, identified as 1,3-cyclohexadiene, in a peak at 500 K and benzene immediately thereafter at 530 K. Acrolein is evolved from the surface in three peaks: a peak independent of coverage at 495 K, attributed to decomposition of an intermediate that is partly converted to C 6H 8; a coverage-dependent peak that shifts from 370 K (low coverage) to 260 K (high coverage), which is attributed to adsorption at 5-fold coordinated Ti sites; and a multilayer state at 160 K. Water and acrolein compete for 5-fold coordinated titanium sites when dosed sequentially. The addition of water also opens a new reaction pathway, leading to the hydrogenation of acrolein to form propanal. Water has no effect on the yield of 1,3-cyclohexadiene. Exposure of the surface to oxygen prior to acrolein dosing quenches the evolution of acrolein at 495 K and concurrently eliminates the coupling. From these results, we propose that reduced subsurface defects such as titanium ion interstitials play a role in the reactions observed here. The notion that subsurface defects may contribute to the reactivity of organic molecules over reducible oxide substrates may prove to be general.

  17. Effect of halideions on the surface-enhanced Raman spectroscopy of methylene blue for borohydride-reduced silver colloid

    International Nuclear Information System (INIS)

    Dong Xiao; Gu Huaimin; Liu Fang

    2011-01-01

    The surface enhanced Raman scattering (SERS) spectrum of methylene blue (MB) was studied when adding a range of halideions to borohydride-reduced silver colloid. The halideions such as chloride, bromide and iodide were added as aggregating agents to study the effects of halideions on SERS spectroscopy of MB and observe which halideion gives the greatest enhancement for borohydride-reduced silver colloids. The SERS spectra of MB were also detected over a wide range of concentrations of halideions to find the optimum concentration of halideions for SERS enhancement. From the results of this study, the intensity of SERS signal of MB was enhanced significantly when adding halideions to the colloid. Among the three kinds of halideions, chloride gives the greatest enhancement on SERS signal. The enhancement factors for MB with optimal concentration of chloride, bromide and iodide are 3.44x10 4 , 2.04x10 4 , and 1.0x10 4 , respectively. The differences of the SERS spectra of MB when adding different kinds and concentrations of halideions to the colloid may be attributed to the both effects of extent of aggregation of the colloid and the modification of silver surface chemistry. The purpose of this study is to further investigate the effect of halideions on borohydride-reduced silver colloid and to make the experimental conditions suitable for detecting some analytes in high efficiency on rational principles.

  18. The Children Speak

    Science.gov (United States)

    Jacobs, Erin

    2008-01-01

    Public spaces that promote play and discovery are popping up everywhere from metropolitan cities to rural and suburban settings. Playgrounds such as David Rockwell's Imagination Playground in New York City and the Memorial Park Playground in Wilsonville, Oregon, present a stark contrast to the steel and plastic structures found at fast-food…

  19. CONCENTRATION OF HARMFUL SUBSTANCES REDUCING IN SURFACE LAYER OF ATMOSPHERE AT RHEOSTAT LOCOMOTIVE TESTS

    Directory of Open Access Journals (Sweden)

    E. A. Bondar

    2010-06-01

    Full Text Available It is shown that at present an acceptable way of reducing the concentration of harmful substances in the surface layer of the atmosphere at rheostat tests of locomotives is their dispersion in a large volume of air. Channels, installed above an exhaust pipe of diesel locomotive with a break at the gas flow, work as ejectors. We have solved jointly the equation of aerodynamic characteristics of the ejector device and the equation of diffusion of gases; as a result the calculated dependence for determining the necessary height of ejector device has been obtained.

  20. Numerical Simulations of Scattering of Light from Two-Dimensional Rough Surfaces Using the Reduced Rayleigh Equation

    Directory of Open Access Journals (Sweden)

    Tor eNordam

    2013-09-01

    Full Text Available A formalism is introduced for the non-perturbative, purely numerical, solution of the reduced Rayleigh equation for the scattering of light from two-dimensional penetrable rough surfaces. Implementation and performance issues of the method, and various consistency checks of it, are presented and discussed. The proposed method is found, within the validity of the Rayleigh hypothesis, to give reliable results. For a non-absorbing metal surface the conservation of energy was explicitly checked, and found to be satisfied to within 0.03%, or better, for the parameters assumed. This testifies to the accuracy of the approach and a satisfactory discretization. As an illustration, we calculate the full angular distribution of the mean differential reflection coefficient for the scattering of p- or s-polarized light incident on two-dimensional dielectric or metallic randomly rough surfaces defined by (isotropic or anisotropic Gaussian and cylindrical power spectra. Simulation results obtained by the proposed method agree well with experimentally measured scattering data taken from similar well-characterized, rough metal samples, or to results obtained by other numerical methods.

  1. Comet 67P/Churyumov-Gerasimenko Surface Composition as a Playground for Radiative Transfer Modeling and Laboratory Measurements: an international ISSI team

    Science.gov (United States)

    Stephan, K.; Ciarniello, M.; Beck, P.; Filacchione, G.; Moroz, L.; Pilorget, C.; Pommerol, A.; Quirico, E.; Raponi, A.; Schröder, S.; Kappel, D.; Vinogradoff, V.; Istiqomah, I.; Rousseau, B.

    2017-12-01

    Remote sensing observations at visible-infrared (VIS-IR) wavelengths of the nucleus of comet 67P/Churyumov-Gerasimenko performed by VIRTIS (Coradini et al., 2007) aboard the Rosetta mission have revealed a surface ubiquitously covered by low-albedo material (Capaccioni et al., 2015; Ciarniello et al., 2015), characterized by the presence of refractory and semi-volatile organics and dark opaque phases (Capaccioni et al., 2015; Quirico et al., 2016). However, a quantitative determination of the physical properties (grain size, porosity) and chemical composition of the surface regolith, from spectrophotometric analysis, is still missing. This subject will be investigated within an international team hosted by ISSI (International Space Science Institute), taking advantage of available and dedicated laboratory reflectance measurements on cometary analogue samples and radiative transfer models (Hapke, 2012; Shkuratov et al., 1999; Monte Carlo ray-tracing), applied to Rosetta spectrophotometric observations of the nucleus. The convergence between models and measurements will allow us to provide a thorough characterization of 67P/Churyumov-Gerasimenko surface. At the same time, the comparison of theoretical predictions with results from laboratory reflectance spectroscopy on powders of analog materials give us the possibility to constrain the capability of the models to characterize their composition (endmember abundances and mixing modalities) and physical properties. We report about the state of the art of laboratory reflectance spectroscopy and spectral modeling applied to 67P/Churyumov-Gerasimenko VIS-IR spectrum as well as preliminary results of the team activity and planned future work. Acknowledgements: the team thanks ISSI-Switzerland for the logistic and financial support.

  2. The effect of dentine surface preparation and reduced application time of adhesive on bonding strength.

    Science.gov (United States)

    Saikaew, Pipop; Chowdhury, A F M Almas; Fukuyama, Mai; Kakuda, Shinichi; Carvalho, Ricardo M; Sano, Hidehiko

    2016-04-01

    This study evaluated the effects of surface preparation and the application time of adhesives on the resin-dentine bond strengths with universal adhesives. Sixty molars were cut to exposed mid-coronal dentine and divided into 12 groups (n=5) based on three factors; (1) adhesive: G-Premio Bond (GP, GC Corp., Tokyo, Japan), Clearfil Universal Bond (CU, Kuraray Noritake Dental Inc., Okayama, Japan) and Scotchbond Universal Adhesive (SB, 3M ESPE, St. Paul, MN, USA); (2) smear layer preparation: SiC paper ground dentine or bur-cut dentine; (3) application time: shortened time or as manufacturer's instruction. Fifteen resin-dentine sticks per group were processed for microtensile bond strength test (μTBS) according to non-trimming technique (1mm(2)) after storage in distilled water (37 °C) for 24h. Data were analyzed by three-way ANOVA and Dunnett T3 tests (α=0.05). Fractured surfaces were observed under scanning electron microscope (SEM). Another 12 teeth were prepared and cut into slices for SEM examination of bonded interfaces. μTBS were higher when bonded to SiC-ground dentine according to manufacturer's instruction. Bonding to bur-cut dentine resulted in significantly lower μTBS (padhesive resin interface. This was more pronounced when adhesives were bonded with a reduced application time and on bur cut dentine. The performance of universal adhesives can be compromised on bur cut dentine and when applied with a reduced application time. Copyright © 2016 Elsevier Ltd. All rights reserved.

  3. Surface impedance and optimum surface resistance of a superconductor with an imperfect surface

    Science.gov (United States)

    Gurevich, Alex; Kubo, Takayuki

    2017-11-01

    We calculate a low-frequency surface impedance of a dirty, s -wave superconductor with an imperfect surface incorporating either a thin layer with a reduced pairing constant or a thin, proximity-coupled normal layer. Such structures model realistic surfaces of superconducting materials which can contain oxide layers, absorbed impurities, or nonstoichiometric composition. We solved the Usadel equations self-consistently and obtained spatial distributions of the order parameter and the quasiparticle density of states which then were used to calculate a low-frequency surface resistance Rs(T ) and the magnetic penetration depth λ (T ) as functions of temperature in the limit of local London electrodynamics. It is shown that the imperfect surface in a single-band s -wave superconductor results in a nonexponential temperature dependence of Z (T ) at T ≪Tc which can mimic the behavior of multiband or d -wave superconductors. The imperfect surface and the broadening of the gap peaks in the quasiparticle density of states N (ɛ ) in the bulk give rise to a weakly temperature-dependent residual surface resistance. We show that the surface resistance can be optimized and even reduced below its value for an ideal surface by engineering N (ɛ ) at the surface using pair-breaking mechanisms, particularly by incorporating a small density of magnetic impurities or by tuning the thickness and conductivity of the normal layer and its contact resistance. The results of this work address the limit of Rs in superconductors at T ≪Tc , and the ways of engineering the optimal density of states by surface nanostructuring and impurities to reduce losses in superconducting microresonators, thin-film strip lines, and radio-frequency cavities for particle accelerators.

  4. Anhydride-functional silane immobilized onto titanium surfaces induces osteoblast cell differentiation and reduces bacterial adhesion and biofilm formation

    International Nuclear Information System (INIS)

    Godoy-Gallardo, Maria; Guillem-Marti, Jordi; Sevilla, Pablo; Manero, José M.; Gil, Francisco J.

    2016-01-01

    Bacterial infection in dental implants along with osseointegration failure usually leads to loss of the device. Bioactive molecules with antibacterial properties can be attached to titanium surfaces with anchoring molecules such as silanes, preventing biofilm formation and improving osseointegration. Properties of silanes as molecular binders have been thoroughly studied, but research on the biological effects of these coatings is scarce. The aim of the present study was to determine the in vitro cell response and antibacterial effects of triethoxysilypropyl succinic anhydride (TESPSA) silane anchored on titanium surfaces. X-ray photoelectron spectroscopy confirmed a successful silanization. The silanized surfaces showed no cytotoxic effects. Gene expression analyses of Sarcoma Osteogenic (SaOS-2) osteoblast-like cells cultured on TESPSA silanized surfaces reported a remarkable increase of biochemical markers related to induction of osteoblastic cell differentiation. A manifest decrease of bacterial adhesion and biofilm formation at early stages was observed on treated substrates, while favoring cell adhesion and spreading in bacteria–cell co-cultures. Surfaces treated with TESPSA could enhance a biological sealing on implant surfaces against bacteria colonization of underlying tissues. Furthermore, it can be an effective anchoring platform of biomolecules on titanium surfaces with improved osteoblastic differentiation and antibacterial properties. - Highlights: • TESPSA silane induces osteoblast differentiation. • TESPSA reduces bacterial adhesion and biofilm formation. • TESPSA is a promising anchoring platform of biomolecules onto titanium.

  5. Anhydride-functional silane immobilized onto titanium surfaces induces osteoblast cell differentiation and reduces bacterial adhesion and biofilm formation

    Energy Technology Data Exchange (ETDEWEB)

    Godoy-Gallardo, Maria, E-mail: maria.godoy.gallardo@upc.edu [Biomaterials, Biomechanics and Tissue Engineering Group, Department of Materials Science and Metallurgy, Technical University of Catalonia (UPC), ETSEIB, Av. Diagonal 647, 08028 Barcelona (Spain); Centre for Research in NanoEngineering (CRNE) — UPC, C/ Pascual i Vila 15, 08028 Barcelona (Spain); Guillem-Marti, Jordi, E-mail: jordi.guillem.marti@upc.edu [Biomaterials, Biomechanics and Tissue Engineering Group, Department of Materials Science and Metallurgy, Technical University of Catalonia (UPC), ETSEIB, Av. Diagonal 647, 08028 Barcelona (Spain); Centre for Research in NanoEngineering (CRNE) — UPC, C/ Pascual i Vila 15, 08028 Barcelona (Spain); Sevilla, Pablo, E-mail: psevilla@euss.es [Department of Mechanics, Escola Universitària Salesiana de Sarrià (EUSS), C/ Passeig de Sant Bosco, 42, 08017 Barcelona (Spain); Manero, José M., E-mail: jose.maria.manero@upc.edu [Biomaterials, Biomechanics and Tissue Engineering Group, Department of Materials Science and Metallurgy, Technical University of Catalonia (UPC), ETSEIB, Av. Diagonal 647, 08028 Barcelona (Spain); Centre for Research in NanoEngineering (CRNE) — UPC, C/ Pascual i Vila 15, 08028 Barcelona (Spain); Gil, Francisco J., E-mail: francesc.xavier.gil@upc.edu [Biomaterials, Biomechanics and Tissue Engineering Group, Department of Materials Science and Metallurgy, Technical University of Catalonia (UPC), ETSEIB, Av. Diagonal 647, 08028 Barcelona (Spain); Centre for Research in NanoEngineering (CRNE) — UPC, C/ Pascual i Vila 15, 08028 Barcelona (Spain); and others

    2016-02-01

    Bacterial infection in dental implants along with osseointegration failure usually leads to loss of the device. Bioactive molecules with antibacterial properties can be attached to titanium surfaces with anchoring molecules such as silanes, preventing biofilm formation and improving osseointegration. Properties of silanes as molecular binders have been thoroughly studied, but research on the biological effects of these coatings is scarce. The aim of the present study was to determine the in vitro cell response and antibacterial effects of triethoxysilypropyl succinic anhydride (TESPSA) silane anchored on titanium surfaces. X-ray photoelectron spectroscopy confirmed a successful silanization. The silanized surfaces showed no cytotoxic effects. Gene expression analyses of Sarcoma Osteogenic (SaOS-2) osteoblast-like cells cultured on TESPSA silanized surfaces reported a remarkable increase of biochemical markers related to induction of osteoblastic cell differentiation. A manifest decrease of bacterial adhesion and biofilm formation at early stages was observed on treated substrates, while favoring cell adhesion and spreading in bacteria–cell co-cultures. Surfaces treated with TESPSA could enhance a biological sealing on implant surfaces against bacteria colonization of underlying tissues. Furthermore, it can be an effective anchoring platform of biomolecules on titanium surfaces with improved osteoblastic differentiation and antibacterial properties. - Highlights: • TESPSA silane induces osteoblast differentiation. • TESPSA reduces bacterial adhesion and biofilm formation. • TESPSA is a promising anchoring platform of biomolecules onto titanium.

  6. Reducing Motional Decoherence in Ion Traps with Surface Science Methods

    Science.gov (United States)

    Haeffner, Hartmut

    2014-03-01

    Many trapped ions experiments ask for low motional heating rates while trapping the ions close to trapping electrodes. However, in practice small ion-electrode distances lead to unexpected high heating rates. While the mechanisms for the heating is still unclear, it is now evident that surface contamination of the metallic electrodes is at least partially responsible for the elevated heating rates. I will discuss heating rate measurements in a microfabricated surface trap complemented with basic surface science studies. We monitor the elemental surface composition of the Cu-Al alloy trap with an Auger spectrometer. After bake-out, we find a strong Carbon and Oxygen contamination and heating rates of 200 quanta/s at 1 MHz trap frequency. After removing most of the Carbon and Oxygen with Ar-Ion sputtering, the heating rates drop to 4 quanta/s. Interestingly, we still measure the decreased heating rate even after the surface oxidized from the background gas throughout a 40-day waiting time in UHV.

  7. Significant change of local atomic configurations at surface of reduced activation Eurofer steels induced by hydrogenation treatments

    Energy Technology Data Exchange (ETDEWEB)

    Greculeasa, S.G.; Palade, P.; Schinteie, G. [National Institute for Materials Physics, P.O. Box MG-7, 77125, Bucharest-Magurele (Romania); Kuncser, A.; Stanciu, A. [National Institute for Materials Physics, P.O. Box MG-7, 77125, Bucharest-Magurele (Romania); University of Bucharest, Faculty of Physics, 77125, Bucharest-Magurele (Romania); Lungu, G.A. [National Institute for Materials Physics, P.O. Box MG-7, 77125, Bucharest-Magurele (Romania); Porosnicu, C.; Lungu, C.P. [National Institute for Laser, Plasma and Radiation Physics, 77125, Bucharest-Magurele (Romania); Kuncser, V., E-mail: kuncser@infim.ro [National Institute for Materials Physics, P.O. Box MG-7, 77125, Bucharest-Magurele (Romania)

    2017-04-30

    Highlights: • Engineering of Eurofer slab properties by hydrogenation treatments. • Hydrogenation modifies significantly the local atomic configurations at the surface. • Hydrogenation increases the expulsion of the Cr atoms toward the very surface. • Approaching binomial atomic distribution by hydrogenation in the next surface 100 nm. - Abstract: Reduced-activation steels such as Eurofer alloys are candidates for supporting plasma facing components in tokamak-like nuclear fusion reactors. In order to investigate the impact of hydrogen/deuterium insertion in their crystalline lattice, annealing treatments in hydrogen atmosphere have been applied on Eurofer slabs. The resulting samples have been analyzed with respect to local structure and atomic configuration both before and after successive annealing treatments, by X-ray diffractometry (XRD), scanning electron microscopy and energy dispersive spectroscopy (SEM-EDS), X-ray photoelectron spectroscopy (XPS) and conversion electron Mössbauer spectroscopy (CEMS). The corroborated data point out for a bcc type structure of the non-hydrogenated alloy, with an average alloy composition approaching Fe{sub 0.9}Cr{sub 0.1} along a depth of about 100 nm. EDS elemental maps do not indicate surface inhomogeneities in concentration whereas the Mössbauer spectra prove significant deviations from a homogeneous alloying. The hydrogenation increases the expulsion of the Cr atoms toward the surface layer and decreases their oxidation, with considerable influence on the surface properties of the steel. The hydrogenation treatment is therefore proposed as a potential alternative for a convenient engineering of the surface of different Fe-Cr based alloys.

  8. High-Surface-Area Nitrogen-Doped Reduced Graphene Oxide for Electric Double-Layer Capacitors.

    Science.gov (United States)

    Youn, Hee-Chang; Bak, Seong-Min; Kim, Myeong-Seong; Jaye, Cherno; Fischer, Daniel A; Lee, Chang-Wook; Yang, Xiao-Qing; Roh, Kwang Chul; Kim, Kwang-Bum

    2015-06-08

    A two-step method consisting of solid-state microwave irradiation and heat treatment under NH3 gas was used to prepare nitrogen-doped reduced graphene oxide (N-RGO) with a high specific surface area (1007 m(2)  g(-1) ), high electrical conductivity (1532 S m(-1) ), and low oxygen content (1.5 wt %) for electrical double-layer capacitor applications. The specific capacitance of N-RGO was 291 F g(-1) at a current density of 1 A g(-1) , and a capacitance of 261 F g(-1) was retained at 50 A g(-1) , which indicated a very good rate capability. N-RGO also showed excellent cycling stability and preserved 96 % of the initial specific capacitance after 100 000 cycles. Near-edge X-ray absorption fine-structure spectroscopy results provided evidenced for the recovery of π conjugation in the carbon networks with the removal of oxygenated groups and revealed chemical bonding of the nitrogen atoms in N-RGO. The good electrochemical performance of N-RGO is attributed to its high surface area, high electrical conductivity, and low oxygen content. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. In situ iron-57 Moessbauer spectroscopic investigations of the effect of titania surface area on the reducibility of titania-supported iron oxide

    International Nuclear Information System (INIS)

    Berry, F.J.; Du Hongzhang

    1990-01-01

    Iron-57 Moessbauer spectroscopy has been used to monitor the reducibility in hydrogen of iron oxides supported on titania of differing surface areas. The results show that although Fe 3+ in the iron oxide supported on low surface area titania (11 m 2 g -1 ) is not amenable to facile reduction at low temperatures, complete reduction to metallic iron is achieved by treatment at 600deg C. The data also show that the extent of reduction at elevated temperatures exceeds that which is obtained on similar silica- and alumina-supported systems. Fe 3+ in iron oxide supported on higher surface area titania (50 m 2 g -1 and 240 m 2 g -1 ) is partially reduced in hydrogen at 235deg C to Fe 2+ but fails to attain complete reduction to the metallic state following treatment at 600deg C. The results are related to the different dispersions of iron oxide which can be attained on titania of differing surface area and the consequent interactions between the support and the supported phases. (orig.)

  10. Reducing surface water total and methyl mercury concentrations and bioavailability using a coagulation-wetland system

    Science.gov (United States)

    Kraus, T. E.; Fleck, J.; Henneberry, Y. K.; Stumpner, E. B.; Krabbenhoft, D. P.; Bachand, P.; Randall, P.

    2013-12-01

    With the recent passage of laws regulating concentrations and loads of mercury (Hg) in surface waters, there is a need to develop management practices that will reduce the export of Hg from both point and non-point sources. Coagulation with metal based salts to remove particles and dissolved organic matter (DOM) from solution is a practice commonly employed by drinking water utilities. Because dissolved Hg is associated with particles and DOM, it follows that Hg should also be removed during the coagulation process and end up associated with the organo-metal precipitate, termed flocculate (floc). The effectiveness of iron- and aluminum-based coagulants for removing both inorganic and methyl mercury (IHg and MeHg, respectively) from solution was demonstrated in laboratory studies conducted on agricultural drainage waters of the Sacramento-San Joaquin Delta: dissolved concentrations of MeHg decreased by 80% while IHg decreased by 97% following coagulation. To test the field application of this technology, samples were collected from the inflows and outflows of wetland treatment cells constructed in the central Delta of California. This replicated field experiment includes three replicates each of three inflow waters treatments: (1) iron sulfate addition, (2) polyaluminum chloride addition, and (3) untreated controls. Water entering and exiting the nine treatment cells was sampled approximately monthly over a 1-year period for total Hg and MeHg in both the dissolved and particulate aqueous phases. Initial results confirm that coagulant addition is removing Hg (total and methyl, particulate and dissolved) from solution and sequestering it in the floc. Seasonal effects on DOM concentration and other factors appear to effect whether passage through the wetland cells alters surface water dissolved organic carbon (DOC) and Hg concentrations. Related studies will examine whether the presence of the floc affects the production and fate of MeHg within the wetland cells. If

  11. BRITICE-CHRONO: Constraining rates and style of marine-influenced ice sheet decay to provide a data-rich playground for ice sheet modellers

    Science.gov (United States)

    Clark, Chris

    2014-05-01

    Uncertainty exists regarding the fate of the Antarctic and Greenland ice sheets and how they will respond to forcings from sea level and atmospheric and ocean temperatures. If we want to know more about the mechanisms and rate of change of shrinking ice sheets, then why not examine an ice sheet that has fully disappeared and track its retreat through time? If achieved in enough detail such information could become a data-rich playground for improving the next breed of numerical ice sheet models to be used in ice and sea level forecasting. We regard that the last British-Irish Ice Sheet is a good target for this work, on account of its small size, density of information and with its numerous researchers already investigating it. BRITICE-CHRONO is a large (>45 researchers) NERC-funded consortium project comprising Quaternary scientists and glaciologists who will search the seafloor around Britain and Ireland and parts of the landmass in order to find and extract samples of sand, rock and organic matter that can be dated (OSL; Cosmogenic; 14C) to reveal the timing and rate of change of the collapsing British-Irish Ice Sheet. The purpose is to produce a high resolution dataset on the demise on an ice sheet - from the continental shelf edge and across the marine to terrestrial transition. Some 800 new date assessments will be added to those that already exist. This poster reports on the hypotheses that underpin the work. Data on retreat will be collected by focusing on 8 transects running from the continental shelf edge to a short distance (10s km) onshore and acquiring marine and terrestrial samples for geochronometric dating. The project includes funding for 587 radiocarbon, 140 OSL and 158 TCN samples for surface exposure dating; with sampling accomplished by two research cruises and 16 fieldwork campaigns. Results will reveal the timing and rate of change of ice margin recession for each transect, and combined with existing landform and dating databases, will be

  12. An assessment of schoolyard features and behavior patterns in children's utilization and physical activity.

    Science.gov (United States)

    Anthamatten, Peter; Brink, Lois; Kingston, Beverly; Kutchman, Eve; Lampe, Sarah; Nigg, Claudio

    2014-03-01

    Careful research that elucidates how behavior relates to design in the context of elementary school grounds can serve to guide cost-efficient design with the goal of encouraging physical activity (PA). This work explores patterns in children's PA behavior within playground spaces with the specific goal of guiding healthy playground design. Data on children's utilization and PA behavior in 6 playgrounds divided into 106 observation zones were collected in 2005 and 2006 at Denver elementary school playgrounds using the System for Observing Play and Leisure Activity in Youth. Analyses of variance and t tests determined whether there were differences in utilization and behavior patterns across observations zones and between genders. This study provides evidence that children prefer to use certain types of playground zones and that they are more likely to practice moderate-to-vigorous physical activity (MVPA) in some zones. The authors observed statistically significant differences between genders. Boys were more likely to engage in MVPA in zones without equipment, girls were more likely to use zones with equipment. This work suggests that the inclusion or omission of specific playground features may have an impact on the way that children use the spaces.

  13. Electrochemical impedance spectroscopy and Surface Studies of Steel Corrosion by Sulphate-Reducing Bacteria

    International Nuclear Information System (INIS)

    Fathul Karim Sahrani; Zaharah Ibrahim; Madzlan Aziz; Adibah Yahya

    2009-01-01

    Sulphate-reducing bacteria (SRB), implicated in microbiologically influenced corrosion were isolated from the deep subsurface at the vicinity of Pasir Gudang, Johor, Malaysia. Electrochemical impedance spectroscopic (EIS) study was carried out to determine the polarization resistance in various types of culturing solutions, with SRB1, SRB2, combination of SRB1 and SRB2 and without SRBs inoculated (control). EIS results showed that in the presence of SRB1, SRB2 and mixed culture SRB1 and SRB2, polarisation resistance values were 7170, 6370 and 7190 ohms respectively compared to that of control, 92400 ohm. X-ray analysis (EDS) of the specimens indicated high sulphur content in the medium containing SRBs. Localized corrosion was observed on the metal surface which was associated with the SRB activity. (author)

  14. Surface-modified reduced graphene oxide electrodes for capacitors by ionic liquids and their electrochemical properties

    International Nuclear Information System (INIS)

    Kim, Jieun; Kim, Seok

    2014-01-01

    Highlights: • Reduced graphene oxide surface was modified by introduction of ionic liquids. • Microstructure and capacitance of modified electrode were dependent on the ionic liquids contents. • Modification gives electrode better charge transport and higher specific capacitance. • Modified electrode showed the better capacitive performance such as rate capability and cycle stability. - Abstract: In this work, reduced graphene oxide (rGO)/ionic liquids (IL) composites with different weight ratios of IL to rGO were synthesized by a simple method. In these composites, IL contributed to the exfoliation of rGO sheets and to the improvement of the electrochemical properties of the resulting composites by enhancing the ion diffusion and charge transport. The structure of the composites was examined by transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), and Raman spectroscopy. The TEM images showed that IL was coated on the surface of rGO in a translucent manner. The electrochemical analysis of the prepared composites was carried out by performing cyclic voltammetry (CV), galvanostatic charge–discharge, and electrochemical impedance spectroscopy (EIS). Among the prepared composites, the one with a weight ratio of rGO to IL of 1:7 showed the highest specific capacitance of 147.5 F g −1 at a scan rate of 10 mV s −1 . In addition, the rate capability and cycle performance of the composites were enhanced compared to pristine rGO. These enhanced properties make the composites suitable as electrode materials for the better performance supercapacitors

  15. Surface color perception under two illuminants: the second illuminant reduces color constancy

    Science.gov (United States)

    Yang, Joong Nam; Shevell, Steven K.

    2003-01-01

    This study investigates color perception in a scene with two different illuminants. The two illuminants, in opposite corners, simultaneously shine on a (simulated) scene with an opaque dividing wall, which controls how much of the scene is illuminated by each source. In the first experiment, the height of the dividing wall was varied. This changed the amount of each illuminant reaching objects on the opposite side of the wall. Results showed that the degree of color constancy decreased when a region on one side of the wall had cues to both illuminants, suggesting that cues from the second illuminant are detrimental to color constancy. In a later experiment, color constancy was found to improve when the specular highlight cues from the second illuminant were altered to be consistent with the first illuminant. This corroborates the influence of specular highlights in surface color perception, and suggests that the reduced color constancy in the first experiment is due to the inconsistent, though physically correct, cues from the two illuminants.

  16. Surface Plasmon Resonance (SPR Phenomenon of the Oxidizing and Reducing Polypyrrole

    Directory of Open Access Journals (Sweden)

    Nurlaila Rajabiah

    2016-12-01

    Full Text Available Surface Plasmon Resonance (SPR phenomenon of the oxidizing and reducing polypyrrole (PPy have been observed using a modified Au/PPy Kretschmann configuration. The observation was carried out through simulation Winspall 3.02 software and compared with some experimental data refractive index (n, absorbance index (, and thickness (τ reported in other literatures with spectroscopy ellipsometry. This simulation assumed that the SPR system use BK-7 halfcylinder prism (n= 1,515 and the laser beam was generated by HeNe (λ= 632,8 nm. The result showed that the optimum layer thickness of polypyrrole with neutral electrolyte solution in the reduction state is of about 20 nm. The polypyrrole with an acid solution in the oxidation state showed that the reflectivity curve is sharper and the width of the curve is smaller than the neutral electrolyte solution in the reduction state with the SPR angle of about 46,810 and the reflectivity value of about 0,217. Polypyrrole in a state of oxidation and reduction, related to the absorption, film thickness, and dielectric constant of materials, affected to the SPR angle shift and dip curve

  17. Surface sterilization method for reducing microbial contamination of ...

    African Journals Online (AJOL)

    An effective disinfection method for strawberry (Fragaria x ananassa Duch.) cv. Senga Sengana micropropagation using runner tips and nodal segments as explants was developed. The explants were surface sterilized with different sterilants for different durations. The present studies on the effect of different regimes of ...

  18. Effects of reduced surface tension on two-phase diversion cross-flow between subchannels simplifying triangle tight lattice rod bundle

    International Nuclear Information System (INIS)

    Kawahara, Akimaro; Sadatomi, Michio; Higuchi, Tatsuya

    2009-01-01

    Two-phase diversion cross-flow between tight lattice subchannels has been investigated experimentally and analytically. For hydraulically non-equilibrium flows with the pressure difference between the subchannels, experiments were conducted using a vertical multiple-channel with two subchannels simplifying a triangle tight lattice rod bundle. To know the effects of the reduced surface tension on the diversion cross-flow, water and water with a surfactant were used as the test liquids. Data were obtained on the axial variations in the pressure difference between the subchannels, gas and liquid flow rates and void fraction in each subchannel for slug-churn and annular flows. In the analysis, flow redistribution processes due to the diversion cross-flow have been calculated by our subchannel analysis code based on a two-fluid model. From a comparison between the experiment and the code calculation, the code was found to be valid against the present data if the improved constitutive equations of wall and interfacial friction reported in our previous paper were incorporated to account for the reduced surface tension effects. (author)

  19. One-dimensional electron liquid at a surface. Gold nanowires on Ge(001)

    Energy Technology Data Exchange (ETDEWEB)

    Blumenstein, Christian

    2012-09-11

    Self-organized nanowires at semiconductor surfaces offer the unique opportunity to study electrons in reduced dimensions. Notably the dimensionality of the system determines it's electronic properties, beyond the quasiparticle description. In the quasi-one-dimensional (1D) regime with weak lateral coupling between the chains, a Peierls instability can be realized. A nesting condition in the Fermi surface leads to a backfolding of the 1D electron band and thus to an insulating state. It is accompanied by a charge density wave (CDW) in real space that corresponds to the nesting vector. This effect has been claimed to occur in many surface-defined nanowire systems, such as the In chains on Si(111) or the Au reconstructions on the terraced Si(553) and Si(557) surfaces. Therefore a weak coupling between the nanowires in these systems has to be concluded. However theory proposes another state in the perfect 1D limit, which is completely destroyed upon slight coupling to higher dimensions. In this so-called Tomonaga-Luttinger liquid (TLL) state, the quasiparticle description of the Fermi liquid breaks down. Since the interaction between the electrons is enhanced due to the strong confinement, only collective excitations are allowed. This leads to novel effects like spin charge separation, where spin and charge degrees of freedom are decoupled and allowed to travel independently along the 1D-chain. Such rare state has not been realized at a surface until today. This thesis uses a novel approach to realize nanowires with improved confinement by studying the Au reconstructed Ge(001) surface. A new cleaning procedure using piranha solution is presented, in order to prepare a clean and long-range ordered substrate. To ensure optimal growth of the Au nanowires the phase diagram is extensively studied by scanning tunneling microscopy (STM) and low energy electron diffraction (LEED). The structural elements of the chains are revealed and described in high detail. Remarkably

  20. Zinc-ion implanted and deposited titanium surfaces reduce adhesion of Streptococccus mutans

    International Nuclear Information System (INIS)

    Xu Juan; Ding Gang; Li Jinlu; Yang Shenhui; Fang Bisong; Sun Hongchen; Zhou Yanmin

    2010-01-01

    While titanium (Ti) is a commonly used dental implant material with advantageous biocompatible and mechanical properties, native Ti surfaces do not have the ability to prevent bacterial colonization. The objective of this study was to evaluate the chemical composition and bacterial adhesive properties of zinc (Zn) ion implanted and deposited Ti surfaces (Zn-PIIID-Ti) as potential dental implant materials. Surfaces of pure Ti (cp-Ti) were modified with increasing concentrations of Zn using plasma immersion ion implantation and deposition (PIIID), and elemental surface compositions were characterized by X-ray photoelectron spectrometry (XPS). To evaluate bacterial responses, Streptococcus mutans were seeded onto the modifiedTi surfaces for 48 h and subsequently observed by scanning electron microscopy. Relative numbers of bacteria on each surface were assessed by collecting the adhered bacteria, reculturing and counting colony forming units after 48 h on bacterial grade plates. Ti, oxygen and carbon elements were detected on all surfaces by XPS. Increased Zn signals were detected on Zn-PIIID-Ti surfaces, correlating with an increase of Zn-deposition time. Substantial numbers of S. mutans adhered to cp-Ti samples, whereas bacterial adhesion on Zn-PIIID-Ti surfaces signficantly decreased as the Zn concentration increased (p < 0.01). In conclusion, PIIID can successfully introduce Zn onto a Ti surface, forming a modified surface layer bearing Zn ions that consequently deter adhesion of S. mutans, a common bacterium in the oral environment.

  1. Zinc-ion implanted and deposited titanium surfaces reduce adhesion of Streptococccus mutans

    Energy Technology Data Exchange (ETDEWEB)

    Xu Juan, E-mail: doctorxue@126.com [Implant Center, School of Stomatology Jilin University, Changchun, Jilin (China) and Stomatological Hospital, Urumqi, Xinjiang (China); Ding Gang [Department of Stomatology, Yidu Central Hospital, Weifang, Shandong (China); Capital Medical University School of Stomatology, Beijing (China); Li Jinlu; Yang Shenhui; Fang Bisong [Capital Medical University School of Stomatology, Beijing (China); Sun Hongchen, E-mail: hcsun@jlu.edu.cn [Implant Center, School of Stomatology Jilin University, Changchun, Jilin (China); Zhou Yanmin, E-mail: zhouym62@126.com [Implant Center, School of Stomatology Jilin University, Changchun, Jilin (China)

    2010-10-01

    While titanium (Ti) is a commonly used dental implant material with advantageous biocompatible and mechanical properties, native Ti surfaces do not have the ability to prevent bacterial colonization. The objective of this study was to evaluate the chemical composition and bacterial adhesive properties of zinc (Zn) ion implanted and deposited Ti surfaces (Zn-PIIID-Ti) as potential dental implant materials. Surfaces of pure Ti (cp-Ti) were modified with increasing concentrations of Zn using plasma immersion ion implantation and deposition (PIIID), and elemental surface compositions were characterized by X-ray photoelectron spectrometry (XPS). To evaluate bacterial responses, Streptococcus mutans were seeded onto the modifiedTi surfaces for 48 h and subsequently observed by scanning electron microscopy. Relative numbers of bacteria on each surface were assessed by collecting the adhered bacteria, reculturing and counting colony forming units after 48 h on bacterial grade plates. Ti, oxygen and carbon elements were detected on all surfaces by XPS. Increased Zn signals were detected on Zn-PIIID-Ti surfaces, correlating with an increase of Zn-deposition time. Substantial numbers of S. mutans adhered to cp-Ti samples, whereas bacterial adhesion on Zn-PIIID-Ti surfaces signficantly decreased as the Zn concentration increased (p < 0.01). In conclusion, PIIID can successfully introduce Zn onto a Ti surface, forming a modified surface layer bearing Zn ions that consequently deter adhesion of S. mutans, a common bacterium in the oral environment.

  2. Effects of reducing children's television and video game use on aggressive behavior: a randomized controlled trial.

    Science.gov (United States)

    Robinson, T N; Wilde, M L; Navracruz, L C; Haydel, K F; Varady, A

    2001-01-01

    The relationship between exposure to aggression in the media and children's aggressive behavior is well documented. However, few potential solutions have been evaluated. To assess the effects of reducing television, videotape, and video game use on aggressive behavior and perceptions of a mean and scary world. Randomized, controlled, school-based trial. Two sociodemographically and scholastically matched public elementary schools in San Jose, Calif. Third- and fourth-grade students (mean age, 8.9 years) and their parents or guardians. Children in one elementary school received an 18-lesson, 6-month classroom curriculum to reduce television, videotape, and video game use. In September (preintervention) and April (postintervention) of a single school year, children rated their peers' aggressive behavior and reported their perceptions of the world as a mean and scary place. A 60% random sample of children were observed for physical and verbal aggression on the playground. Parents were interviewed by telephone and reported aggressive and delinquent behaviors on the child behavior checklist. The primary outcome measure was peer ratings of aggressive behavior. Compared with controls, children in the intervention group had statistically significant decreases in peer ratings of aggression (adjusted mean difference, -2.4%; 95% confidence interval [CI], -4.6 to -0.2; P =.03) and observed verbal aggression (adjusted mean difference, -0.10 act per minute per child; 95% CI, -0.18 to -0.03; P =.01). Differences in observed physical aggression, parent reports of aggressive behavior, and perceptions of a mean and scary world were not statistically significant but favored the intervention group. An intervention to reduce television, videotape, and video game use decreases aggressive behavior in elementary schoolchildren. These findings support the causal influences of these media on aggression and the potential benefits of reducing children's media use.

  3. Riparian shrub buffers reduce surface water pollutant loads

    Science.gov (United States)

    W. A. Geyer; C. Barden; K. Mankin; D. Devlin

    2003-01-01

    Surface water resources in Kansas often contain concentrations of pesticides, nutrients, and sediments that are of concern to local citizens. The United States Geological Survey reported in 1999 that 97 percent of streams and 82 percent of lakes in Kansas would not fully support all uses as designated by state statutes (U.S. Geological Survey 1999). Bacteria and...

  4. Electrokinetics on superhydrophobic surfaces

    International Nuclear Information System (INIS)

    Papadopoulos, Periklis; Deng Xu; Vollmer, Doris; Butt, Hans-Jürgen

    2012-01-01

    On a superhydrophobic surface a liquid is exposed to a large air-water interface. The reduced wall friction is expected to cause a higher electro-osmotic mobility. On the other hand, the low charge density of a superhydrophobic surface reduces the electro-osmotic mobility. Due to a lack of experimental data it has not been clear so far whether the reduced wall friction or the reduced charge density dominate the electrokinetic mobilities. To separate the relative contributions of electrophoresis and electro-osmosis, the mobilities of colloids on a negatively charged hydrophilic, a superhydrophobic (Cassie) and a partially hydrophilized superhydrophobic (Cassie composite) coating were measured. To vary the charge density as well as its sign with respect to those of the colloids the partially hydrophilized surfaces were coated with polyelectrolytes. We analyzed the electrokinetic mobilities of negatively charged polystyrene colloids dispersed in aqueous medium on porous hydrophilic and superhydrophobic surfaces by confocal laser scanning electron microscopy. In all cases, the external electric field was parallel to the surface. The total electrokinetic mobilities on the superhydrophobic (Cassie) and negatively charged partially hydrophilized (Cassie composite) surfaces were similar, showing that electro-osmosis is small compared to electrophoresis. The positively charged Cassie composite surfaces tend to ‘trap’ the colloids due to attracting electrostatic interactions and rough morphology, reducing the mobility. Thus, either the charge density of the coatings in the Cassie composite state or its slip length is too low to enhance electro-osmosis.

  5. PLAYGROUND DISEÑOS E INFRAESTRUCTURAS SEGURAS PARA NUESTROS NIÑOS Y NIÑAS…UNA URGENCIA EN COSTA RICA

    Directory of Open Access Journals (Sweden)

    María Morera Castro

    2007-07-01

    Full Text Available Este artículo tiene como propósito dar a conocer los parámetros necesarios para el diseño e implementación de campos de juego seguros para la población. Ya que por medio de los campos de juego se suministran oportunidades únicas de desarrollo integral, especialmente en la edad infantil. En estos espacios públicos, los niños y las niñas tienen que aprender a resolver conflictos para seguir adelante con su juego, su diversión y su desarrollo. Este espacio lúdico se convierte en un lugar de aprendizaje que conlleva procesos de formación y grandes beneficios sociales, emocionales, físicos, cognoscitivos, intelectuales y espirituales. Sin embargo, estos beneficios se ven disminuidos por la falta de conciencia de las compañías constructoras que los diseñan en lugares no aptos, poniendo en riesgo a la población, también por el poco interés de las comunidades y la población adulta, en optimizar las condiciones para su uso. Por lo cual, es de suma importancia antes, durante y después de la construcción de un campo de juego tomar en cuenta: el diseño, la construcción, el material, los implementos, los componentes y los procedimientos que se deben de tener para que cumplan con los requerimientos necesarios de seguridad, y sin dejar de lado el objetivo de su creación, o sea un área diseñada, equipada, localizada y exclusiva para el juego y que facilite la formación integral de la población. Es urgente, por tanto, que en Costa Rica se establezcan legislaciones claras que garanticen el cumplimiento en cuanto a la construcción, diseño y utilización de los playgrounds, sin poner en riesgo la salud, previniendo cualquier tipo de accidente y garantizando los derechos inalienables de cada costarricense.

  6. Surface functionalization of dopamine coated iron oxide nanoparticles for various surface functionalities

    Energy Technology Data Exchange (ETDEWEB)

    Sherwood, Jennifer; Xu, Yaolin; Lovas, Kira [Chemical and Biological Engineering, The University of Alabama, Tuscaloosa , AL 35487 (United States); Qin, Ying [Alabama Innovation and Mentoring of Entrepreneurs, The University of Alabama, Tuscaloosa, AL 35487 (United States); Bao, Yuping, E-mail: ybao@eng.ua.edu [Chemical and Biological Engineering, The University of Alabama, Tuscaloosa , AL 35487 (United States)

    2017-04-01

    We present effective conjugation of four small molecules (glutathione, cysteine, lysine, and Tris(hydroxymethyl)aminomethane) onto dopamine-coated iron oxide nanoparticles. Conjugation of these molecules could improve the surface functionality of nanoparticles for more neutral surface charge at physiological pH and potentially reduce non-specific adsorption of proteins to nanoparticles surfaces. The success of conjugation was evaluated with dynamic light scattering by measuring the surface charge changes and Fourier transform infrared spectroscopy for surface chemistry analysis. The stability of dopamine-coated nanoparticles and the ability of conjugated nanoparticles to reduce the formation of protein corona were evaluated by measuring the size and charge of the nanoparticles in biological medium. This facile conjugation method opens up possibilities for attaching various surface functionalities onto iron oxide nanoparticle surfaces for biomedical applications.

  7. Surface functionalization of dopamine coated iron oxide nanoparticles for various surface functionalities

    International Nuclear Information System (INIS)

    Sherwood, Jennifer; Xu, Yaolin; Lovas, Kira; Qin, Ying; Bao, Yuping

    2017-01-01

    We present effective conjugation of four small molecules (glutathione, cysteine, lysine, and Tris(hydroxymethyl)aminomethane) onto dopamine-coated iron oxide nanoparticles. Conjugation of these molecules could improve the surface functionality of nanoparticles for more neutral surface charge at physiological pH and potentially reduce non-specific adsorption of proteins to nanoparticles surfaces. The success of conjugation was evaluated with dynamic light scattering by measuring the surface charge changes and Fourier transform infrared spectroscopy for surface chemistry analysis. The stability of dopamine-coated nanoparticles and the ability of conjugated nanoparticles to reduce the formation of protein corona were evaluated by measuring the size and charge of the nanoparticles in biological medium. This facile conjugation method opens up possibilities for attaching various surface functionalities onto iron oxide nanoparticle surfaces for biomedical applications.

  8. Supplemental Environmental Impact Statement, Guam and Commonwealth of the Northern Mariana Islands Military Relocation (2012 Roadmap Adjustments)

    Science.gov (United States)

    2015-07-01

    whether for cultural practices, recreation, tourism , or academic study would also diminish the cultural resources of Guam. MITIGATION MEASURES AND...opportunities for important cultural practices. Reduced access to cultural sites, whether for cultural practices, recreation, tourism , or academic study...playgrounds, active sports areas, parks, residences, motels, hotels, schools, churches, places of worship, libraries, and hospitals. C 72 (Exterior

  9. Mining soil phosphorus by zero P-application: an effective method to reduce the risk of P loading to surface water

    NARCIS (Netherlands)

    Salm, van der C.; Chardon, W.J.; Koopmans, G.F.

    2007-01-01

    This study aims to find field evidence for the effectiveness of P-mining to reduce the risk of P leaching to surface water. In 2002, a P-mining was conducted on four grassland sites in the Netherlands on sand (two sites), peat and clay soils. The mining plots received no P and an annual N surplus of

  10. The Effect of Aptamer Concetration towards Reduced Graphene Oxide-Field Effect Transistor Surface Channel for Biosensor Application

    Science.gov (United States)

    Syafiq Zainol Abidin, Azrul; Rahim, Ruslinda Abdul; Huan, Chow Yong; Maidin, Nur Nasyifa Mohd; Atiqah Ahmad, Nurul; Hashwan, Saeed S. Ba; Faudzi, Fatin Nabilah Mohd; Hong, Voon Chun

    2018-03-01

    Aptamer are artificially produce bioreceptor that has been developed to bind with various target biomolecules such as ion, cells, protein and small molecules. In this research, an aptamer concentration of 0.5 nM, 1 nM, 5 nM, 10 nM, and 50 nM were immobilized on reduced graphene oxide (rGO) integrated with field effect transistor (FET) respectively to study the effect of aptamer concentration toward rGO surface for stable biosensing platform. The 0.5 nM concentration of aptamer shows the highest current result of 84.3 µA at 1 V applied through the source and drain. After immobilized with aminated aptamer, the conductivity shows significant reduction due to the formation of amide bond on rGO surface between aminated aptamer and carboxyl group on rGO. The electrical performance of FET integrated with rGO shows stable electrical performance suitable to be used in the biosensing application.

  11. Sensitizing Clostridium difficile Spores With Germinants on Skin and Environmental Surfaces Represents a New Strategy for Reducing Spores via Ambient Mechanisms

    Directory of Open Access Journals (Sweden)

    Michelle Marie Nerandzic

    2017-10-01

    Full Text Available Background: Clostridium difficile is a leading cause of healthcare-associated infections worldwide. Prevention of C. difficile transmission is challenging because spores are not killed by alcohol-based hand sanitizers or many commonly used disinfectants. One strategy to control spores is to induce germination, thereby rendering the spores more susceptible to benign disinfection measures and ambient stressors. Methods/Results: C. difficile spores germinated on skin after a single application of cholic acid-class bile salts and co-germinants; for 4 C. difficile strains, recovery of viable spores from skin was reduced by ~0.3 log10CFU to 2 log10CFU after 2 hours and ~1 log10CFU to >2.5 log 10CFU after 24 hours. The addition of taurocholic acid to 70% and 30% ethanol significantly enhanced reduction of viable spores on skin and on surfaces. Desiccation, and to a lesser extent the presence of oxygen, were identified as the stressors responsible for reductions of germinated spores on skin and surfaces. Additionally, germinated spores became susceptible to killing by pH 1.5 hydrochloric acid, suggesting that germinated spores that remain viable on skin and surfaces might be killed by gastric acid after ingestion. Antibiotic-treated mice did not become colonized after exposure to germinated spores, whereas 100% of mice became colonized after exposure to the same quantity of dormant spores. Conclusions: Germination could provide a new approach to reduce C. difficile spores on skin and in the environment and to render surviving spores less capable of causing infection. Our findings suggest that it may be feasible to develop alcohol-based hand sanitizers containing germinants that reduce spores on hands.

  12. Rumble surfaces

    CSIR Research Space (South Africa)

    National Institute for Transport and Road

    1977-01-01

    Full Text Available Rumble surfaces are intermittent short lengths of coarse-textured road surfacings on which vehicle tyres produce a rumbling sound. used in conjunction with appropriate roadsigns and markings, they can reduce accidents on rural roads by alerting...

  13. Biomimetic Fluorocarbon Surfactant Polymers Reduce Platelet Adhesion on PTFE/ePTFE Surfaces

    Science.gov (United States)

    Wang, Shuwu; Gupta, Anirban Sen; Sagnella, Sharon; Barendt, Pamela M.; Kottke-Marchant, Kandice; Marchant, Roger E.

    2010-01-01

    We describe a series of fluorocarbon surfactant polymers designed as surface-modifying agents for improving the thrombogenicity of ePTFE vascular graft materials by the reduction of platelet adhesion. The surfactant polymers consist of a poly(vinyl amine) backbone with pendent dextran and perfluoroundecanoyl branches. Surface modification is accomplished by a simple dip-coating process in which surfactant polymers undergo spontaneous surface-induced adsorption and assembly on PTFE/ePTFE surface. The adhesion stability of the surfactant polymer on PTFE was examined under dynamic shear conditions in PBS and human whole blood with a rotating disk system. Fluorocarbon surfactant polymer coatings with three different dextran to perfluorocarbon ratios (1:0.5, 1:1 and 1:2) were compared in the context of platelet adhesion on PTFE/ePTFE surface under dynamic flow conditions. Suppression of platelet adhesion was achieved for all three coated surfaces over the shear-stress range of 0–75 dyn/cm2 in platelet-rich plasma (PRP) or human whole blood. The effectiveness depended on the surfactant polymer composition such that platelet adhesion on coated surfaces decreased significantly with increasing fluorocarbon branch density at 0 dyn/cm2. Our results suggest that fluorocarbon surfactant polymers can effectively suppress platelet adhesion and demonstrate the potential application of the fluorocarbon surfactant polymers as non-thrombogenic coatings for ePTFE vascular grafts. PMID:19323880

  14. Design Options to Reduce Development Cost of First Generation Surface Reactors

    International Nuclear Information System (INIS)

    Poston, David I.; Marcille, Thomas F.

    2006-01-01

    Low-power surface reactors have the potential to have the lowest development cost of any space reactor application, primarily because system alpha (mass/kg) is not of utmost importance and mission lifetimes do not have to be a decade or more. Even then, the development cost of a surface reactor can vary substantially depending on the performance requirements (e.g. mass, power, lifetime, reliability) and technical development risk deemed acceptable by the end-user. It is important for potential users to be aware of these relationships before they determine their future architecture (i.e. decide what they need). Generally, the greatest potential costs of a space reactor program are a nuclear-powered ground test and extensive material development campaigns, so it is important to consider options that can minimize the need for or complexity of such tasks. The intended goal of this paper is to inform potential surface reactor users of the potential sensitivities of surface reactor development cost to design requirements, and areas where technical risk can be traded with development cost

  15. Effects of iron-reducing bacteria and nitrate-reducing bacteria on the transformations of iron corrosion products, magnetite and siderite, formed at the surface of non-alloy steel

    International Nuclear Information System (INIS)

    Etique, Marjorie

    2014-01-01

    Radioactive waste is one of the major problems facing the nuclear industry. To circumvent this issue France plans to store vitrified high-level nuclear waste in a stainless steel container, placed into a non-alloy steel overpack, at a depth of 500 m in an argillaceous formation. The main iron corrosion products formed at the surface of the non-alloy steel are siderite (Fe II CO 3 ) and magnetite (Fe II Fe III 2 O 4 ). These compounds are formed in the anoxic conditions present in the nuclear waste repository and play a protective role against corrosion as a passive layer. This work aims to investigate the activity of nitrate-reducing bacteria (NRB, Klebsiella mobilis) and iron-reducing bacteria (IRB, Shewanella putrefaciens) during the transformation of siderite and magnetite, especially those involved in anoxic iron biogeochemical cycle. Klebsiella mobilis and Shewanella putrefaciens were first incubated with siderite or magnetite suspensions (high surface specific area) in order to exacerbate the microbial iron transformation, subsequently incubated with a magnetite/siderite film synthesized by anodic polarization at applied current density. The transformation of siderite and magnetite by direct or indirect microbial processes led to the formation of carbonated green rust (Fe II 4 Fe III 2 (OH) 12 CO 3 ). As a transient phase shared by several bacterial reactions involving Fe II and Fe III , this compound is the cornerstone of the anoxic iron biogeochemical cycle. The novelty of this thesis is the consideration of bacterial metabolisms of NRB and IRB often overlooked in bio-corrosion processes. (author) [fr

  16. Investigation of surface potentials in reduced graphene oxide flake by Kelvin probe force microscopy

    Science.gov (United States)

    Negishi, Ryota; Takashima, Kai; Kobayashi, Yoshihiro

    2018-06-01

    The surface potential (SP) of reduced graphene oxide (rGO) flakes prepared by thermal treatments of GO under several conditions was analyzed by Kelvin probe force microscopy. The low-crystalline rGO flakes in which a significant amount of oxygen functional groups and structural defects remain have a much lower SP than mechanically exfoliated graphene free from oxygen and defects. On the other hand, the highly crystalline rGO flake after a thermal treatment for the efficient removal of oxygen functional groups and healing of structural defects except for domain boundary shows SP equivalent to that of the mechanically exfoliated graphene. These results indicate that the work function of rGO is sensitively modulated by oxygen functional groups and structural defects remaining after the thermal reduction process, but is not affected significantly by the domain boundary remaining after the healing of structural defects through the thermal treatment at high temperature.

  17. Supercapacitors based on highly dispersed polypyrrole-reduced graphene oxide composite with a folded surface

    Science.gov (United States)

    Wang, Anqi; Zhou, Xi; Qian, Tao; Yu, Chenfei; Wu, Shishan; Shen, Jian

    2015-08-01

    Highly dispersed polypyrrole particles were decorated on reduced graphene oxide sheets using a facile in situ synthesis route. The prepared composite, which obtained a folded surface, shows remarkable performance as the electrode material of supercapacitors. The specific capacitance reaches 564.1 F g-1 at a current density of 1 A g-1 and maintains 86.4 % after 1000 charging-discharging cycles at a current density of 20 A g-1, which indicates a good cycling stability. Furthermore, the prepared supercapacitor demonstrates an ultrahigh energy density of 50.13 Wh kg-1 at power density of 0.40 kW kg-1, and remains of 45.33 Wh kg-1 even at high power density of 8.00 kW kg-1, which demonstrate that the hybrid supercapacitor can be a promising energy storage system for fast and efficient energy storage in the future.

  18. Waste Tyres as Heat Sink to Reduce the Driveway Surface Temperatures in Malaysia

    Directory of Open Access Journals (Sweden)

    Aniza Abdul Aziz

    2013-12-01

    Full Text Available The development of roads and driveways are on the rise as automobiles are now a necessity to all. This excessive development with its requirements increased the urban heat temperature and the generation of waste tyres. Waste tyre management has therefore been taken seriously by developed countries and since the European directive to ban used tyre products and whole tire disposal from landfill in 2003 and 2006 respectively, many researchers have looked for alternative ways to use the waste tyre. In Malaysia, The Smart and Cool Home Developer attempted to develop an eco-house by utilising waste tyre as the foundation for the driveway and claimed that the buried tyres act as a heat sink for the concrete and reduce the surface temperature of the driveway. Hence investigations were conducted on two sample houses to investigate this phenomenon. Findings from this pilot study show that waste tyres do act as a heat sink to the concrete driveways which affect the ambient temperature and relative humidity of the immediate surroundings.

  19. The role of wastewater treatment in reducing pollution of surface waters with zearalenone.

    Science.gov (United States)

    Gromadzka, Karolina; Waśkiewicz, Agnieszka; Świetlik, Joanna; Bocianowski, Jan; Goliński, Piotr

    2015-06-01

    Zearalenone (ZEA) is a mycotoxin produced by some Fusarium species in food and feed. The toxicity of ZEA and its metabolites is related to the chemical structure of the mycotoxin, which is similar to naturally occurring oestrogens. Currently, there is increasing awareness of the presence of fungi and their toxic metabolites in the aquatic environment. One of the sources of these compounds are the effluents from wastewater treatment plants. The average annual efficiency of zearalenone reduction in the Łęczyca plant in our three-year study was in the range from 51.35 to 69.70 %. The threeway analysis of variance (year, month, and kind of wastewater) shows that the main effects of all factors and all interactions between them were significant for zearalenone and dissolved organic carbon content. Our findings suggest that wastewater is not the main source of surface water pollution with zearalenone. Future research should investigate the means to reduce ZEA and its migration from the fields through prevention strategies such as breeding for crops, plant debris management (crop rotation, tillage), and/or chemical and biological control.

  20. Ankle taping can reduce external ankle joint moments during drop landings on a tilted surface.

    Science.gov (United States)

    Sato, Nahoko; Nunome, Hiroyuki; Hopper, Luke S; Ikegami, Yasuo

    2017-09-20

    Ankle taping is commonly used to prevent ankle sprains. However, kinematic assessments investigating the biomechanical effects of ankle taping have provided inconclusive results. This study aimed to determine the effect of ankle taping on the external ankle joint moments during a drop landing on a tilted surface at 25°. Twenty-five participants performed landings on a tilted force platform that caused ankle inversion with and without ankle taping. Landing kinematics were captured using a motion capture system. External ankle inversion moment, the angular impulse due to the medio-lateral and vertical components of ground reaction force (GRF) and their moment arm lengths about the ankle joint were analysed. The foot plantar inclination relative to the ground was assessed. In the taping condition, the foot plantar inclination and ankle inversion angular impulse were reduced significantly compared to that of the control. The only component of the external inversion moment to change significantly in the taped condition was a shortened medio-lateral GRF moment arm length. It can be assumed that the ankle taping altered the foot plantar inclination relative to the ground, thereby shortening the moment arm of medio-lateral GRF that resulted in the reduced ankle inversion angular impulse.

  1. Investigations on reducing microbiologically-influenced corrosion of aluminum by using super-hydrophobic surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Liu Tao, E-mail: liutao@shmtu.edu.c [Institute of Marine Materials Science and Engineering, Shanghai Maritime University, Shanghai 201306 (China); Dong Lihua; Liu Tong; Yin Yansheng [Institute of Marine Materials Science and Engineering, Shanghai Maritime University, Shanghai 201306 (China)

    2010-07-15

    Electrochemical impedance spectroscopy, potentiodynamic polarization and scanning electron microscopy were carried out to determine the effect of super-hydrophobic surfaces on the marine bacterium Vibrio natriegens (V. natriegens) adhesion. Four different samples were prepared in order to investigate the anti-biocorrosion mechanism of super-hydrophobic surfaces. Potentiodynamic polarization suggested that the V. natriegens attached on the surface mainly enhanced the reaction kinetics of the anodic reaction and accelerated the dissolution of aluminum. EIS results were interpreted with different equivalent circuits to model the physicoelectric characteristics of the electrode/biofilm/solution interface. The results showed that neither anodization nor chemical modification could decrease the bacterial adhesion and corrosion rate individually. V. natriegens showed only weak attachment to the super-hydrophobic surface, and the biocorrosion mechanism was closely associated with surface energy and surface topography.

  2. Investigations on reducing microbiologically-influenced corrosion of aluminum by using super-hydrophobic surfaces

    International Nuclear Information System (INIS)

    Liu Tao; Dong Lihua; Liu Tong; Yin Yansheng

    2010-01-01

    Electrochemical impedance spectroscopy, potentiodynamic polarization and scanning electron microscopy were carried out to determine the effect of super-hydrophobic surfaces on the marine bacterium Vibrio natriegens (V. natriegens) adhesion. Four different samples were prepared in order to investigate the anti-biocorrosion mechanism of super-hydrophobic surfaces. Potentiodynamic polarization suggested that the V. natriegens attached on the surface mainly enhanced the reaction kinetics of the anodic reaction and accelerated the dissolution of aluminum. EIS results were interpreted with different equivalent circuits to model the physicoelectric characteristics of the electrode/biofilm/solution interface. The results showed that neither anodization nor chemical modification could decrease the bacterial adhesion and corrosion rate individually. V. natriegens showed only weak attachment to the super-hydrophobic surface, and the biocorrosion mechanism was closely associated with surface energy and surface topography.

  3. Short communication: Evaluation of a sol-gel-based stainless steel surface modification to reduce fouling and biofilm formation during pasteurization of milk.

    Science.gov (United States)

    Liu, Dylan Zhe; Jindal, Shivali; Amamcharla, Jayendra; Anand, Sanjeev; Metzger, Lloyd

    2017-04-01

    Milk fouling and biofilms are common problems in the dairy industry across many types of processing equipment. One way to reduce milk fouling and biofilms is to modify the characteristics of milk contact surfaces. This study examines the viability of using Thermolon (Porcelain Industries Inc., Dickson, TN), a sol-gel-based surface modification of stainless steel, during thermal processing of milk. We used stainless steel 316L (control) and sol-gel-modified coupons in this study to evaluate fouling behavior and bacterial adhesion. The surface roughness as measured by an optical profiler indicated that the control coupons had a slightly smoother finish. Contact angle measurements showed that the modified surface led to a higher water contact angle, suggesting a more hydrophobic surface. The modified surface also had a lower surface energy (32.4 ± 1.4 mN/m) than the control surface (41.36 ± 2.7 mN/m). We evaluated the susceptibility of control and modified stainless steel coupons to fouling in a benchtop plate heat exchanger. We observed a significant reduction in the amount of fouled layer on modified surfaces. We found an average fouling weight of 19.21 mg/cm 2 and 0.37 mg/cm 2 on the control and modified stainless steel coupons, respectively. We also examined the adhesion of Bacillus and biofilm formation, and observed that the modified stainless steel surface offered greater resistance to biofilm formation. Overall, the Thermolon-modified surface showed potential in the thermal processing of milk, offering significantly lower fouling and bacterial attachment than the control surface. Copyright © 2017 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

  4. Intelligent playgrounds

    DEFF Research Database (Denmark)

    Larsen, Lasse Juel

    2009-01-01

    This paper examines play, gaming and learning in regard to intelligent playware developed for outdoor use. The key questions are how does these novel artefacts influence the concept of play, gaming and learning. Up until now play and game have been understood as different activities. This paper...... examines if the sharp differentiation between the two can be uphold in regard to intelligent playware for outdoor use. Play and game activities will be analysed and viewed in conjunction with learning contexts. This paper will stipulate that intelligent playware facilitates rapid shifts in contexts...

  5. Wise retained in the endoplasmic reticulum inhibits Wnt signaling by reducing cell surface LRP6.

    Science.gov (United States)

    Guidato, Sonia; Itasaki, Nobue

    2007-10-15

    The Wnt signaling pathway is tightly regulated by extracellular and intracellular modulators. Wise was isolated as a secreted protein capable of interacting with the Wnt co-receptor LRP6. Studies in Xenopus embryos revealed that Wise either enhances or inhibits the Wnt pathway depending on the cellular context. Here we show that the cellular localization of Wise has distinct effects on the Wnt pathway readout. While secreted Wise either synergizes or inhibits the Wnt signals depending on the partner ligand, ER-retained Wise consistently blocks the Wnt pathway. ER-retained Wise reduces LRP6 on the cell surface, making cells less susceptible to the Wnt signal. This study provides a cellular mechanism for the action of Wise and introduces the modulation of cellular susceptibility to Wnt signals as a novel mechanism of the regulation of the Wnt pathway.

  6. Reducing strength prevailing at root surface of plants promotes reduction of Ag+ and generation of Ag(0/Ag2O nanoparticles exogenously in aqueous phase.

    Directory of Open Access Journals (Sweden)

    Peddisetty Pardha-Saradhi

    Full Text Available Potential of root system of plants from wide range of families to effectively reduce membrane impermeable ferricyanide to ferrocyanide and blue coloured 2,6-dichlorophenol indophenol (DCPIP to colourless DCPIPH2 both under non-sterile and sterile conditions, revealed prevalence of immense reducing strength at root surface. As generation of silver nanoparticles (NPs from Ag+ involves reduction, present investigations were carried to evaluate if reducing strength prevailing at surface of root system can be exploited for reduction of Ag+ and exogenous generation of silver-NPs. Root system of intact plants of 16 species from 11 diverse families of angiosperms turned clear colorless AgNO3 solutions, turbid brown. Absorption spectra of these turbid brown solutions showed silver-NPs specific surface plasmon resonance peak. Transmission electron microscope coupled with energy dispersive X-ray confirmed the presence of distinct NPs in the range of 5-50 nm containing Ag. Selected area electron diffraction and powder X-ray diffraction patterns of the silver NPs showed Bragg reflections, characteristic of crystalline face-centered cubic structure of Ag(0 and cubic structure of Ag2O. Root system of intact plants raised under sterile conditions also generated Ag(0/Ag2O-NPs under strict sterile conditions in a manner similar to that recorded under non-sterile conditions. This revealed the inbuilt potential of root system to generate Ag(0/Ag2O-NPs independent of any microorganism. Roots of intact plants reduced triphenyltetrazolium to triphenylformazon and impermeable ferricyanide to ferrocyanide, suggesting involvement of plasma membrane bound dehydrogenases in reduction of Ag+ and formation of Ag(0/Ag2O-NPs. Root enzyme extract reduced triphenyltetrazolium to triphenylformazon and Ag+ to Ag(0 in presence of NADH, clearly establishing potential of dehydrogenases to reduce Ag+ to Ag(0, which generate Ag(0/Ag2O-NPs. Findings presented in this manuscript put

  7. Investigation of surface roughness on etched glass surfaces

    International Nuclear Information System (INIS)

    Papa, Z.; Budai, J.; Farkas, B.; Toth, Z.

    2011-01-01

    Roughening the surface of solar cells is a common practice within the photovoltaic industry as it reduces reflectance, and thus enhances the performance of devices. In this work the relationship between reflectance characterized by the haze parameter, surface roughness and optical properties was investigated. To achieve this goal, model samples were prepared by hydrofluoric acid etching of glass for various times and measured by optical microscopy, spectroscopic ellipsometry, scanning electron microscopy, and atomic force microscopy. Our investigation showed that the surface reflectance was decreased not only by the roughening of the surface but also by the modification of the depth profile and lowering of the refractive index of the surface domain of the samples.

  8. Decontamination of floor surfaces

    International Nuclear Information System (INIS)

    Smirous, F.

    1983-01-01

    Requirements are presented put on the surfaces of floors of radiochemical workplaces. The mechanism is described of retaining the contaminant in the surface of the flooring, ways of reducing the hazards of floor surface contamination, decontamination techniques and used decontamination agents. (J.P.)

  9. Urban soil pollution and the playfields of small children

    Science.gov (United States)

    Jartun, M.; Ottesen, R. T.; Steinnes, E.

    2003-05-01

    The chemical composition of urban surface soil in Tromsø, northern Norway has been mapped to describe the environmental load of toxic elements in different parts of the city. Surface soil samples were collected from 275 locations throughout the city center and nearby suburban areas. Natural background concentrations were determined in samples of the local bedrock. Surface soil in younger, suburban parts of the city shows low concentrations of heavy metals, reflecting the local geochemistry. The inner and older parts of the city are generally polluted with lead (Pb), zinc (Zn) and tin (Sn). The most important sources of this urban soil pollution are probably city fires, industrial and domestic waste, traffic, and shipyards. In this paper two different approaches have been used. First, as a result of the general mapping, 852 soil and sand samples from kindergartens and playgrounds were analyzed. In this study concentrations of arsenic (As) up to 1800ppm were found, most likely due to the extensive use of CCA (copper, chromium, arsenic) impregnated wood in sandboxes and other playground equipment. This may represent a significant health risk especially to children having a high oral intake of contaminated sand and soil. Secondly a pattern of tin (Sn) concentrations was found in Tromsøcity with especially high values near shipyards. Further investigation indicated that this pattern most probably reflected the use of the highty toxic tributyltin (TBT). Thus détermination of total Sn in surface soils could be a cost-effective way to localize sources of TBT contamination in the environment.

  10. The world of children in the capital of Tuva

    Directory of Open Access Journals (Sweden)

    Vladimir A. Kisel

    2016-02-01

    Full Text Available The architectural specifics of the city of Kyzyl, capital of the Republic of Tuva (Russian Federation, have so far been understudied. This also concerns children’s playgrounds. Our article aims to analyze their specific features as objects of urban architecture, sculpture and sociocultural anthropology. Tuvans do not have a tradition for setting apart plots of land for children’s games. The construction of playgrounds in Tuva began after its accession to the USSR in 1944 by borrowing the already existing Soviet construction standards. In the absence of a railway linking Tuva to the rest of the USSR, playsets were made on the spot, of wood as the most easily available material. After the collapse of the USSR, centralized control over the federal education system, including institutions for children, weakened. Not only municipal agencies, but individuals as well could now get involved in urban improvement. A number of distinctively picturesque playgrounds appeared in the city in the 1990s and early 2000s, giving rise to a set of specific subjects of decorative sculpture featuring a plethora of ethnic imagery: wrestlers, cloth ornaments, folklore characters, Buddhist symbols, etc. Besides volunteer groups of amateur artists and builders, professional stonemasons also worked on playgrounds, utilizing the techniques of both monumental art and small outdoor statuary. In 2003 the federal Cabinet adopted a new state standard, which set clear demands for equipping children’s playgrounds. Outdoor sport facilities and playsets could now be constructed only by certified companies. This led to a change in aesthetics and a new set of imagery, where transport and machinery featured prominently. At the moment, Kyzyl still has a number of playgrounds with decorative structure, although they are clearly doomed. This understandable and irreversible change will nevertheless deprive the capital of Tuva of one of its most interesting and expressive

  11. ITER safety task NID-5a: on the effect of tritium sorption on building surfaces as a passive mechanism for reducing airborne concentrations

    International Nuclear Information System (INIS)

    Natalizio, A.

    1994-09-01

    As part of the source term analysis for ITER, it is important to investigate the potential for building surface interaction with tritium as a potential attenuation mechanism, which in the absence of engineered systems may be effective in reducing tritium environmental releases. (author). 2 refs., 8 tabs., 3 figs

  12. Contour adaptation reduces the spreading of edge induced colors.

    Science.gov (United States)

    Coia, Andrew J; Crognale, Michael A

    2017-04-25

    Brief exposure to flickering achromatic outlines of an area causes a reduction in the brightness contrast of the surface inside the area. This contour adaptation to achromatic contours does not reduce surface contrast when the surface is chromatic (the saturation or colorimetric purity of the surface is maintained). In addition to reducing the brightness of physical luminance contrast, contour adaptation also reduces (or even reverses) the illusory brightness contrast seen in the Craik-O'Brien-Cornsweet illusion, in which two physically identical grey areas appear different brightness because of a sharp luminance edge separating them. Chromatic color spreading illusions also occur with chromatic inducing edges, and an unanswered question is whether contour adaptation can reduce the perceived contrast of illusory color spreading from edges, even though it cannot reduce the perceived contrast of physical surface color. The current studies use a color spreading illusion known as the watercolor effect in order to test whether illusory color spreading is affected by contour adaptation. The general findings of physical achromatic contrast being reduced and chromatic contrast being robust to contour adaptation were replicated. However, both illusory brightness and color were reduced by contour adaptation, even when the illusion edges only differed in chromatic contrast with each other and the background. Additional studies adapting to chromatic contours showed opposite effects on illusory color contrast than achromatic adaptation. Copyright © 2017 Elsevier Ltd. All rights reserved.

  13. Unraveling the oxygen vacancy structures at the reduced Ce O2(111 ) surface

    Science.gov (United States)

    Han, Zhong-Kang; Yang, Yi-Zhou; Zhu, Beien; Ganduglia-Pirovano, M. Verónica; Gao, Yi

    2018-03-01

    Oxygen vacancies at ceria (Ce O2 ) surfaces play an essential role in catalytic applications. However, during the past decade, the near-surface vacancy structures at Ce O2(111 ) have been questioned due to the contradictory results from experiments and theoretical simulations. Whether surface vacancies agglomerate, and which is the most stable vacancy structure for varying vacancy concentration and temperature, are being heatedly debated. By combining density functional theory calculations and Monte Carlo simulations, we proposed a unified model to explain all conflicting experimental observations and theoretical results. We find a novel trimeric vacancy structure which is more stable than any other one previously reported, which perfectly reproduces the characteristics of the double linear surface oxygen vacancy clusters observed by STM. Monte Carlo simulations show that at low temperature and low vacancy concentrations, vacancies prefer subsurface sites with a local (2 × 2) ordering, whereas mostly linear surface vacancy clusters do form with increased temperature and degree of reduction. These results well explain the disputes about the stable vacancy structure and surface vacancy clustering at Ce O2(111 ) , and provide a foundation for the understanding of the redox and catalytic chemistry of metal oxides.

  14. Preparation of antinutrients-reduced dhokla using response surface process optimisation

    NARCIS (Netherlands)

    Sharma, Anand; Kumari, Sarita; Nout, Martinus J.R.; Sarkar, Prabir K.

    2018-01-01

    Dhokla, a popular indigenous savoury dish of India, is prepared by soaking bengalgram dal and rice, grinding separately, mixing the batters, and spontaneously fermenting and steaming of mixed batter. Central composite rotatable response surface designs for soaking, fermentation and steaming at

  15. Use of Remote Technology in the Surface Water Environmental Monitoring Program at SRS Reducing Measurements in the Field - 13336

    International Nuclear Information System (INIS)

    Eddy, T.; Terry, B.; Meyer, A.; Hall, J.; Allen, P.; Hughey, D.; Hartley, T.

    2013-01-01

    There are a wide range of sensor and remote technology applications available for use in environmental monitoring programs. Each application has its own set of limitations and can be challenging when attempting to utilize it under diverse environmental field conditions. The Savannah River Site Environmental Monitoring Program has implemented several remote sensing and surface water flow technologies that have increased the quality of the data while reducing the number of field measurements. Implementation of this technology reduced the field time for personnel that commute across the Savannah River Site (SRS) over a span of 310 square miles. The wireless surface water flow technology allows for immediate notification of changing field conditions or equipment failure thus reducing data-loss or erroneous field data and improving data-quality. This wireless flow technology uses the stage-to-flow methodology coupled with implementation of a robust highly accurate Acoustic Doppler Profiler system for measuring discharge under various field conditions. Savings for implementation of the wireless flow application and Flowlink R technology equates to approximately 1175 hours annually for the radiological liquid effluent and surveillance programs. The SonTek River Suveyor and Flowtracker technologies are utilized for calibration of the wireless flow monitoring devices in the site streams and validation of effluent flows at the SRS. Implementation of similar wireless devices is also planned in the National Pollutant Discharge Elimination System (NPDES) Storm-water Monitoring Program. SRS personnel have been developing a unique flow actuator device. This device activates an ISCO TM automated sampler under flowing conditions at storm-water outfall locations across the site. This technology is unique in that it was designed to be used under field conditions with rapid changes in flow and sedimentation where traditional actuators have been unsuccessful in tripping the automated

  16. Experience in a Climate Microworld: Influence of Surface and Structure Learning, Problem Difficulty, and Decision Aids in Reducing Stock-Flow Misconceptions

    Directory of Open Access Journals (Sweden)

    Medha Kumar

    2018-03-01

    Full Text Available Research shows that people’s wait-and-see preferences for actions against climate change are a result of several factors, including cognitive misconceptions. The use of simulation tools could help reduce these misconceptions concerning Earth’s climate. However, it is still unclear whether the learning in these tools is of the problem’s surface features (dimensions of emissions and absorptions and cover-story used or of the problem’s structural features (how emissions and absorptions cause a change in CO2 concentration under different CO2 concentration scenarios. Also, little is known on how problem’s difficulty in these tools (the shape of CO2 concentration trajectory, as well as the use of these tools as a decision aid influences performance. The primary objective of this paper was to investigate how learning about Earth’s climate via simulation tools is influenced by problem’s surface and structural features, problem’s difficulty, and decision aids. In experiment 1, we tested the influence of problem’s surface and structural features in a simulation called Dynamic Climate Change Simulator (DCCS on subsequent performance in a paper-and-pencil Climate Stabilization (CS task (N = 100 across four between-subject conditions. In experiment 2, we tested the effects of problem’s difficulty in DCCS on subsequent performance in the CS task (N = 90 across three between-subject conditions. In experiment 3, we tested the influence of DCCS as a decision aid on subsequent performance in the CS task (N = 60 across two between-subject conditions. Results revealed a significant reduction in people’s misconceptions in the CS task after performing in DCCS compared to when performing in CS task in the absence of DCCS. The decrease in misconceptions in the CS task was similar for both problems’ surface and structural features, showing both structure and surface learning in DCCS. However, the proportion of misconceptions was similar across

  17. Occurrence of soil-transmitted helminths on playgrounds of nursery ...

    African Journals Online (AJOL)

    STHs are prevalent on play grounds of nursery and primary schools in Plateau State. Improved hygiene and sanitation, fencing of school premises and the regulation of school population will help to reduce environmental contamination and human infections. Présence d'helminthes transmis par le sol sur les terrains de jeux ...

  18. Interaction of propylene with reduced surface of chromium molybdate

    International Nuclear Information System (INIS)

    Konovalova, N.D.; Belokopytov, Yu.V.

    1978-01-01

    It has been found that reduction of oxidated chromium molybdate sample by propylene at 450 deg C does not change the form of energy surface heterogeneity and also practically does not effect activation desorption energy of C 3 H 6 . It is shown that oxygen of this catalyst volume is movable and is responsible for formation of products of C 3 H 6 partial oxidation (acetic aldehyde and acrolein) in the sample reduction by propylene

  19. Radionuclide transfer onto ground surface in surface water flow, 1

    International Nuclear Information System (INIS)

    Mukai, Masayuki; Takebe, Shinichi; Komiya, Tomokazu; Kamiyama, Hideo

    1991-07-01

    Radionuclides migration in ground surface water flow is considered to be one of the important path way in the scenario for environmental migration of radionuclides leaked from low level radioactive waste repository. Simulating the slightly sloped surface on which contaminated solution is flowing downward, testing for radionuclide migration on ground surface had been started. As it's first step, an experiment was carried out under the condition of restricted infiltration in order to elucidate the adsorption behavior of radionuclides onto the loamy soil surface in related with hydraulic conditions. Radionuclides concentration change in effluent solution with time and a concentration distribution of radionuclides adsorbed on the ground surface were obtained from several experimental conditions combining the rate and the duration time of the water flow. The radionuclides concentration in the effluent solution was nearly constant during each experimental period, and was reduced under the condition of lower flow rate. The surface distribution of radionuclides concentration showed two distinctive regions. The one was near the inlet vessel where the concentration was promptly reducing, and the other was following the former where the concentration was nearly constant. The characteristic surface distribution of radionuclides concentration can be explained by a two dimensional diffusion model with a first order adsorption reaction, based on the advection of flow rate distribution in perpendicular direction. (author)

  20. Controlled lecithin release from a hierarchical architecture on blood-contacting surface to reduce hemolysis of stored red blood cells.

    Science.gov (United States)

    Shi, Qiang; Fan, Qunfu; Ye, Wei; Hou, Jianwen; Wong, Shing-Chung; Xu, Xiaodong; Yin, Jinghua

    2014-06-25

    Hemolysis of red blood cells (RBCs) caused by implant devices in vivo and nonpolyvinyl chloride containers for RBC preservation in vitro has recently gained much attention. To develop blood-contacting biomaterials with long-term antihemolysis capability, we present a facile method to construct a hydrophilic, 3D hierarchical architecture on the surface of styrene-b-(ethylene-co-butylene)-b-styrene elastomer (SEBS) with poly(ethylene oxide) (PEO)/lecithin nano/microfibers. The strategy is based on electrospinning of PEO/lecithin fibers onto the surface of poly [poly(ethylene glycol) methyl ether methacrylate] [P(PEGMEMA)]-modified SEBS, which renders SEBS suitable for RBC storage in vitro. We demonstrate that the constructed 3D architecture is composed of hydrophilic micro- and nanofibers, which transforms to hydrogel networks immediately in blood; the controlled release of lecithin is achieved by gradual dissolution of PEO/lecithin hydrogels, and the interaction of lecithin with RBCs maintains the membrane flexibility and normal RBC shape. Thus, the blood-contacting surface reduces both mechanical and oxidative damage to RBC membranes, resulting in low hemolysis of preserved RBCs. This work not only paves new way to fabricate high hemocompatible biomaterials for RBC storage in vitro, but provides basic principles to design and develop antihemolysis biomaterials for implantation in vivo.

  1. Testing road surface treatments to reduce erosion in forest roads in Honduras [Tratamientos de la superficie de rodadura para reducir la erosion en caminos forestales en Honduras

    Science.gov (United States)

    Rivera, Samuel; Kershner, Jeffrey L.; Keller, Gordon R.

    2009-01-01

    Testing road surface treatments to reduce erosion in forest roads in Honduras. Cien. Inv. Agr. 36(3):425-432. Using forest roads produces more erosion and sedimentation than any other forest or agricultural activity. This study evaluated soil losses from a forest road in central Honduras over two consecutive years. We divided a 400-m segment of road into 8 experimental units, each 50 m in length. Four units were treated with Best Management Practices (BMPs) and four were left untreated. The BMP treatments included reshaping the road prism, installing culverts and reshaping of road ditches, compacting 20-cm layers of the road tread, crowning the road surface (3% slope, double drainage), longitudinal sloping (less than 12%), and adding a 10-cm layer of gravel (crush size = 0.63 cm). Soil movement was measured daily during the rainy seasons. The highest soil loss occurred in the control road, around 500 m3 km-1 per year, while the road treated with BMP lost approximately 225 m3km-1 per year. These results show that road surface erosion can be reduced up to 50% with the implementation of surface treatments.

  2. Heavy Metal.

    Science.gov (United States)

    Black, Susan

    2001-01-01

    The Centers for Disease Control and Prevention (CDC) estimate that more than 1 million children ages 5 and under are afflicted with unsafe amounts of lead. Schools can be a source of lead poisoning. Other sources include playgrounds near freeways, playground equipment, contaminated soil, and technology rooms with lead-bearing supplies. Sidebars…

  3. Inequities in coverage of smokefree space policies within the United States

    Directory of Open Access Journals (Sweden)

    Christopher Lowrie

    2017-05-01

    Full Text Available Abstract Background Previous studies have found extensive geographic and demographic differences in tobacco use. These differences have been found to be reduced by effective public policies, including banning smoking in public spaces. Smokefree indoor and outdoor spaces reduce secondhand smoke exposure and denormalize smoking. Methods We evaluated regional and demographic differences in the proportion of the population covered by smokefree policies enacted in the United States prior to 2014, for both adults and children. Results Significant differences in coverage were found by ethnicity, region, income, and education (p < 0.001. Smokefree policy coverage was lower for jurisdictions with higher proportions of poor households, households with no high school diploma and the Southeast region. Increased ethnic heterogeneity was found to be a significant predictor of coverage in indoor “public spaces generally”, meaning that diversity is protective, with differential effect by region (p = 0.004 – which may relate to urbanicity. Children had a low level of protection in playgrounds and schools (~10% covered nationwide – these spaces were found to be covered at lower rates than indoor spaces. Conclusions Disparities in smokefree space policies have potential to exacerbate existing health inequities. A national increase in smokefree policies to protect children in playgrounds and schools is a crucial intervention to reduce such inequities.

  4. Solar Cels With Reduced Contact Areas

    Science.gov (United States)

    Daud, T.; Crotty, G. T.; Kachare, A. H.; Lewis, J. T.

    1987-01-01

    Efficiency of silicon solar cells increased about 20 percent using smaller metal-contact area on silicon at front and back of each cell. Reduction in contact area reduces surface recombination velocity under contact and thus reduces reverse saturation current and increases opencircuit voltage..

  5. Biofunctionalization of silicone rubber with microgroove-patterned surface and carbon-ion implantation to enhance biocompatibility and reduce capsule formation

    Directory of Open Access Journals (Sweden)

    Lei ZY

    2016-10-01

    collagen deposition around implants made from PC-SR. Conclusion: Although the surface chemical properties, dermal fibroblast cell growth, and cell adhesion were not changed by microgroove pattern modification, a more orderly cell arrangement was obtained, leading to enhanced biocompatibility and reduced capsule formation. Thus, this approach to the modification of silicone rubber, in combination with C-ion implantation, should be considered for further investigation and application. Keywords: silicone rubber, biocompatibility, capsule formation, microgroove, C-ion implantation

  6. What's Eating into School Recess? Implications of Extended Eating for Free Play and Physical Activity

    Science.gov (United States)

    Wyver, Shirley; Engelen, Lina; Bundy, Anita; Naughton, Geraldine

    2012-01-01

    An assumption made when designing recess interventions in schools is that there is a clear demarcation between eating time and play time. We used observational data conducted as part of the Sydney Playground Project to test if this assumption was correct. The Sydney Playground Project is a cluster randomised controlled trial of a recess…

  7. CCl 4 chemistry on the reduced selvedge of a α-Fe 2O 3(0 0 0 1) surface: a scanning tunneling microscopy study

    Science.gov (United States)

    Rim, Kwang Taeg; Fitts, Jeffrey P.; Müller, Thomas; Adib, Kaveh; Camillone, Nicholas; Osgood, Richard M.; Joyce, S. A.; Flynn, George W.

    2003-09-01

    Scanning tunneling microscopy (STM) and low energy electron diffraction (LEED) were used to study the degradation of CCl 4 on the reduced selvedge of a natural single crystal α-Fe 2O 3(0 0 0 1) surface in ultrahigh vacuum. Before exposure to CCl 4, STM images indicate that approximately 85% of the reduced surface exhibits a Fe 3O 4(1 1 1) 2 × 2 termination, while the remaining 15% is terminated by 1 × 1 and superstructure phases. Images obtained after room temperature dosing with CCl 4 and subsequent flashing to 600 K reveal that chlorine atoms are adsorbed only on surface regions with the Fe 3O 4(1 1 1) 2 × 2 termination, not on 1 × 1 and superstructure regions. Chlorine atoms from dissociative adsorption of CCl 4 are observed to occupy two distinct positions located atop lattice protrusions and in threefold oxygen vacancy sites. However, in companion chemical labeling experiments, chlorine atoms provided by room temperature, dissociative Cl 2 adsorption on this surface are found to occupy sites atop lattice protrusions exclusively. The clear dissimilarity in STM feature shape and brightness at the two distinct chlorine adsorption sites arising from CCl 4 dissociation as well as the results of the Cl 2 chemical labeling experiments are best explained via reactions on a Fe 3O 4(1 1 1) 2 × 2 selvedge terminated by a 1/4 monolayer of tetrahedrally coordinated iron atoms. On this surface, adsorption atop an iron atom occurs for both the CCl 4 and Cl 2 dissociative reactions. A second adsorption site, assigned as binding to second layer iron atoms left exposed following surface oxygen atom abstraction resulting in the formation of phosgene (COCl 2), only appears in the case of reaction with CCl 4. The reaction mechanism and active site requirements for CCl 4 degradation on iron oxide surfaces are discussed in light of this evidence and in the context of our previously reported results from Auger electron spectroscopy (AES), LEED, temperature-programmed desorption

  8. Nanotexturing of surfaces to reduce melting point.

    Energy Technology Data Exchange (ETDEWEB)

    Garcia, Ernest J.; Zubia, David (University of Texas at El Paso El Paso, TX); Mireles, Jose (Universidad Aut%C3%94onoma de Ciudad Ju%C3%94arez Ciudad Ju%C3%94arez, Mexico); Marquez, Noel (University of Texas at El Paso El Paso, TX); Quinones, Stella (University of Texas at El Paso El Paso, TX)

    2011-11-01

    This investigation examined the use of nano-patterned structures on Silicon-on-Insulator (SOI) material to reduce the bulk material melting point (1414 C). It has been found that sharp-tipped and other similar structures have a propensity to move to the lower energy states of spherical structures and as a result exhibit lower melting points than the bulk material. Such a reduction of the melting point would offer a number of interesting opportunities for bonding in microsystems packaging applications. Nano patterning process capabilities were developed to create the required structures for the investigation. One of the technical challenges of the project was understanding and creating the specialized conditions required to observe the melting and reshaping phenomena. Through systematic experimentation and review of the literature these conditions were determined and used to conduct phase change experiments. Melting temperatures as low as 1030 C were observed.

  9. Experience in a Climate Microworld: Influence of Surface and Structure Learning, Problem Difficulty, and Decision Aids in Reducing Stock-Flow Misconceptions

    OpenAIRE

    Medha Kumar; Varun Dutt; Varun Dutt

    2018-01-01

    Research shows that people’s wait-and-see preferences for actions against climate change are a result of several factors, including cognitive misconceptions. The use of simulation tools could help reduce these misconceptions concerning Earth’s climate. However, it is still unclear whether the learning in these tools is of the problem’s surface features (dimensions of emissions and absorptions and cover-story used) or of the problem’s structural features (how emissions and absorptions cause a ...

  10. The immediate effectiveness of barley straw mulch in reducing soil erodibility and surface runoff generation in Mediterranean vineyards.

    Science.gov (United States)

    Prosdocimi, Massimo; Jordán, Antonio; Tarolli, Paolo; Keesstra, Saskia; Novara, Agata; Cerdà, Artemi

    2016-03-15

    Soil and water loss in agriculture is a major problem throughout the world, and especially in Mediterranean areas. Non-conservation agricultural practices have further aggravated the situation, especially in vineyards, which are affected by one of the highest rates of soil loss among cultivated lands. Therefore, it is necessary to find the right soil practices for more sustainable viticulture. In this regard, straw mulching has proven to be effective in other crop and fire affected soils, but, nonetheless, little research has been carried out in vineyards. This research tests the effect of barley straw mulching on soil erosion and surface runoff on vineyards in Eastern Spain where the soil and water losses are non-sustainable. An experiment was setup using rainfall simulation tests at 55 mm h(-1) over 1h on forty paired plots of 0.24 m(2): twenty bare and twenty straw covered. Straw cover varied from 48 to 90% with a median value of 59% as a result of the application of 75 g of straw per m(2). The use of straw mulch resulted in delayed ponding and runoff generation and, as a consequence, the median water loss decreased from 52.59 to 39.27% of the total rainfall. The straw cover reduced the median sediment concentration in runoff from 9.8 to 3.0 g L(-1) and the median total sediment detached from 70.34 to 15.62 g per experiment. The median soil erosion rate decreased from 2.81 to 0.63 Mg ha(-1)h(-1) due to the straw mulch protection. Straw mulch is very effective in reducing soil erodibility and surface runoff, and this benefit was achieved immediately after the application of the straw. Copyright © 2015 Elsevier B.V. All rights reserved.

  11. System and method for reducing combustion dynamics in a combustor

    Science.gov (United States)

    Uhm, Jong Ho; Ziminsky, Willy Steve; Johnson, Thomas Edward; Srinivasan, Shiva; York, William David

    2016-11-29

    A system for reducing combustion dynamics in a combustor includes an end cap that extends radially across the combustor and includes an upstream surface axially separated from a downstream surface. A combustion chamber is downstream of the end cap, and tubes extend from the upstream surface through the downstream surface. Each tube provides fluid communication through the end cap to the combustion chamber. The system further includes means for reducing combustion dynamics in the combustor. A method for reducing combustion dynamics in a combustor includes flowing a working fluid through tubes that extend axially through an end cap that extends radially across the combustor and obstructing at least a portion of the working fluid flowing through a first set of the tubes.

  12. Reducing N losses through surface runoff from rice-wheat rotation by improving fertilizer management.

    Science.gov (United States)

    Cao, Yansheng; Sun, Huifeng; Liu, Yaqin; Fu, Zishi; Chen, Guifa; Zou, Guoyan; Zhou, Sheng

    2017-02-01

    To better understand N runoff losses from rice-wheat rotation and demonstrate the effectiveness of improved fertilizer management in reducing N runoff losses, a field study was conducted for three consecutive rice-wheat rotations. Nitrogen losses through surface runoff were measured for five treatments, including CK without N application, C200, C300 simulating the conventional practices, CO200, and CO300. Optimum N rate was applied for C200 and CO200, and 30% of chemical fertilizer was substituted with organic fertilizer for CO200 and CO300 with respect to C200 and C300, respectively. Rice season had higher runoff coefficients than wheat season. Approximately 52% of total N was lost as NH 4 + -N in rice season, ranging from 21 to 83%, and in wheat season, the proportion of NO 3 - -N in total N averaged 53% with a variation from 38 to 67%. The N treatments lost less total N in rice season (1.67-10.7 kg N ha -1 ) than in wheat season (1.72-17.1 kg N ha -1 ). These suggested that a key to controlling N runoff losses from rice-wheat rotation was to limit NO 3 - -N accumulation in wheat season. In both seasons, N runoff losses for C200 and CO300 were lower than those for C300. CO200 better cut N losses than C200 and CO300, with 64 and 57% less N in rice and wheat seasons than C300, respectively. Compared with the conventional practices, optimum N inputs integrated with co-application of organic and chemical fertilizers could reduce N runoff losses with a better N balance under rice-wheat rotation.

  13. Radioactive surface contamination monitors

    International Nuclear Information System (INIS)

    Aoyama, Kei; Minagoshi, Atsushi; Hasegawa, Toru

    1994-01-01

    To reduce radiation exposure and prevent contamination from spreading, each nuclear power plant has established a radiation controlled area. People and articles out of the controlled area are checked for the surface contamination of radioactive materials with surface contamination monitors. Fuji Electric has repeatedly improved these monitors on the basis of user's needs. This paper outlines typical of a surface contamination monitor, a personal surface contamination monitor, an article surface contamination monitor and a laundry monitor, and the whole-body counter of an internal contamination monitor. (author)

  14. Synthesis of battery grade reduced silver powder

    International Nuclear Information System (INIS)

    Qadeer, R.; Hameed, M.; Ikram, S.; Munir, A.

    2002-01-01

    Process for production of battery grade reduced silver powder, an active positive material for zinc-silver oxide batteries, having specific characteristics has been optimized and the synthesized reduced silver powder was characterized. Results reveal that the values of bulk density (1.25 0.1 g/cm3) and activity (73.27 %) of synthesized reduced silver powder lies within the recommended range for use as battery material. It has purity ≥ 98% and contains Fe and Cu as traces in the concentration range of 30 5 ppm and 15 7 ppm respectively. Others determined values of surface and pores parameters are: surface area 2.6 .4 m2/g: pore volume 3.10 cm3/g: pore diameter 0.043 mu m and porosity 20%. XRD studies reveal that reduced silver powder has a cubic structure. (author)

  15. Binary release of ascorbic acid and lecithin from core-shell nanofibers on blood-contacting surface for reducing long-term hemolysis of erythrocyte.

    Science.gov (United States)

    Shi, Qiang; Fan, Qunfu; Ye, Wei; Hou, Jianwen; Wong, Shing-Chung; Xu, Xiaodong; Yin, Jinghua

    2015-01-01

    There is an urgent need to develop blood-contacting biomaterials with long-term anti-hemolytic capability. To obtain such biomaterials, we coaxially electrospin [ascorbic acid (AA) and lecithin]/poly (ethylene oxide) (PEO) core-shell nanofibers onto the surface of styrene-b-(ethylene-co-butylene)-b-styrene elastomer (SEBS) that has been grafted with poly (ethylene glycol) (PEG) chains. Our strategy is based on that the grafted layers of PEG render the surface hydrophilic to reduce the mechanical injure to red blood cells (RBCs) while the AA and lecithin released from nanofibers on blood-contacting surface can actively interact with RBCs to decrease the oxidative damage to RBCs. We demonstrate that (AA and lecithin)/PEO core-shell structured nanofibers have been fabricated on the PEG grafted surface. The binary release of AA and lecithin in the distilled water is in a controlled manner and lasts for almost 5 days; during RBCs preservation, AA acts as an antioxidant and lecithin as a lipid supplier to the membrane of erythrocytes, resulting in low mechanical fragility and hemolysis of RBCs, as well as high deformability of stored RBCs. Our work thus makes a new approach to fabricate blood-contacting biomaterials with the capability of long-term anti-hemolysis. Copyright © 2014 Elsevier B.V. All rights reserved.

  16. MILD CHOLESTEROL DEPLETION REDUCES AMYLOID-β PRODUCTION BY IMPAIRING APP TRAFFICKING TO THE CELL SURFACE

    Science.gov (United States)

    Guardia-Laguarta, Cristina; Coma, Mireia; Pera, Marta; Clarimón, Jordi; Sereno, Lidia; Agulló, José M.; Molina-Porcel, Laura; Gallardo, Eduard; Deng, Amy; Berezovska, Oksana; Hyman, Bradley T.; Blesa, Rafael; Gómez-Isla, Teresa; Lleó, Alberto

    2009-01-01

    It has been suggested that cellular cholesterol levels can modulate the metabolism of the amyloid precursor protein (APP) but the underlying mechanism remains controversial. In the current study, we investigate in detail the relationship between cholesterol reduction, APP processing and γ-secretase function in cell culture studies. We found that mild membrane cholesterol reduction led to a decrease in Aβ40 and Aβ42 in different cell types. We did not detect changes in APP intracellular domain or Notch intracellular domain generation. Western blot analyses showed a cholesterol-dependent decrease in the APP C-terminal fragments and cell surface APP. Finally, we applied a fluorescence resonance energy transfer (FRET)-based technique to study APP-Presenilin 1 (PS1) interactions and lipid rafts in intact cells. Our data indicate that cholesterol depletion reduces association of APP into lipid rafts and disrupts APP-PS1 interaction. Taken together, our results suggest that mild membrane cholesterol reduction impacts the cleavage of APP upstream of γ-secretase and appears to be mediated by changes in APP trafficking and partitioning into lipid rafts. PMID:19457132

  17. Engineered Multifunctional Surfaces for Fluid Handling

    Science.gov (United States)

    Thomas, Chris; Ma, Yonghui; Weislogel, Mark

    2012-01-01

    Designs incorporating variations in capillary geometry and hydrophilic and/or antibacterial surface properties have been developed that are capable of passive gas/liquid separation and passive water flow. These designs can incorporate capillary grooves and/or surfaces arranged to create linear and circumferential capillary geometry at the micro and macro scale, radial fin configurations, micro holes and patterns, and combinations of the above. The antibacterial property of this design inhibits the growth of bacteria or the development of biofilm. The hydrophilic property reduces the water contact angle with a treated substrate such that water spreads into a thin layer atop the treated surface. These antibacterial and hydrophilic properties applied to a thermally conductive surface, combined with capillary geometry, create a novel heat exchanger capable of condensing water from a humid, two-phase water and gas flow onto the treated heat exchanger surfaces, and passively separating the condensed water from the gas flow in a reduced gravity application. The overall process to generate the antibacterial and hydrophilic properties includes multiple steps to generate the two different surface properties, and can be divided into two major steps. Step 1 uses a magnetron-based sputtering technique to implant the silver atoms into the base material. A layer of silver is built up on top of the base material. Completion of this step provides the antibacterial property. Step 2 uses a cold-plasma technique to generate the hydrophilic surface property on top of the silver layer generated in Step 1. Completion of this step provides the hydrophilic property in addition to the antibacterial property. Thermally conductive materials are fabricated and then treated to create the antibacterial and hydrophilic surface properties. The individual parts are assembled to create a condensing heat exchanger with antibacterial and hydrophilic surface properties and capillary geometry, which is

  18. On the Use of Surface Porosity to Reduce Unsteady Lift

    Science.gov (United States)

    Tinetti, Ana F.; Kelly, Jeffrey J.; Bauer, Steven X. S.; Thomas, Russell H.

    2001-01-01

    An innovative application of existing technology is proposed for attenuating the effects of transient phenomena, such as rotor-stator and rotor-strut interactions, linked to noise and fatigue failure in turbomachinery environments. A computational study was designed to assess the potential of passive porosity technology as a mechanism for alleviating interaction effects by reducing the unsteady lift developed on a stator airfoil subject to wake impingement. The study involved a typical high bypass fan Stator airfoil (solid baseline and several porous configurations), immersed in a free field and exposed to the effects of a transversely moving wake. It was found that, for the airfoil under consideration, the magnitude of the unsteady lift could be reduced more than 18% without incurring significant performance losses.

  19. [Detection of surface EMG signal using active electrode].

    Science.gov (United States)

    He, Qinghua; Peng, Chenglin; Wu, Baoming; Wang, He

    2003-09-01

    Research of surface electromyogram(EMG) signal is important in rehabilitation medicine, sport medicine and clinical diagnosis, accurate detection of signal is the base of quantitative analysis of surface EMG signal. In this article were discussed how to reduce possible noise in the detection of surface EMG. Considerations on the design of electrode unit were presented. Instrumentation amplifier AD620 was employed to design a bipolar active electrode for use in surface EMG detection. The experiments showed that active electrode could be used to improve signal/noise ratio, reduce noise and detect surface EMG signal effectively.

  20. Methods of reducing non-specific adsorption in microfluidic biosensors

    International Nuclear Information System (INIS)

    Choi, Seokheun; Chae, Junseok

    2010-01-01

    Non-specific adsorption (NSA) of biomolecules is a persistent challenge in microfluidic biosensors. Microfluidic biosensors often have immobilized bioreceptors such as antibodies, enzymes, DNAs, etc, via linker molecules such as SAMs (self-assembled monolayers) to enhance immobilization. However, the linker molecules are very susceptible to NSA, causing false responses and decreasing sensitivity. In this paper, we present design methods to reduce the NSA of alkanethiol SAMs, which are popular linker molecules on microfluidic biosensors. Three design parameters were studied for two different chain-length SAMs (n = 2 and 10): (i) SAM incubation time, (ii) surface roughness [0.8 nm and 4.4 nm RMS (root mean square)] and (iii) gold crystal re-growth along (1 1 1) the target orientation. NSA was monitored by surface plasmon resonance (SPR). The results suggest that increased SAM incubation time reduces NSA, and that short-chain SAMs respond more favorably than the long-chain SAMs. Both SAMs were shown to be sensitive to surface roughness, and long-chain SAMs reduced NSA by 75%. Gold crystal re-growth along (1 1 1) the target orientation profoundly reduced NSA on the short-chain SAM. On a gold surface where surface roughness was 0.8 nm and there was strong directional alignment along the (1 1 1) gold crystal, final concentrations of nonspecifically bound proteins were 0.05 ng mm −2 (fibrinogen) and 0.075 ng mm −2 (lysozyme)—significantly lower than other known methods. The results show that optimizing three parameters (SAM incubation time, gold surface roughness and gold crystal orientation) improved SAM sensitivity for fibrinogen–anti-fibrinogen conjugates by a factor of 5 in 2.94 pM, suggesting that the methods are effective for reducing NSA in microfluidic biosensors.

  1. Insecticide-treated bed nets reduce plasma antibody levels and limit the repertoire of antibodies to Plasmodium falciparum variant surface antigens

    DEFF Research Database (Denmark)

    Askjaer, N; Maxwell, C; Chambo, W

    2001-01-01

    The use of insecticide-treated bed nets (ITN) has been documented to reduce malaria morbidity and mortality in areas with endemic malaria, but concerns have been raised that ITN usage could affect the acquisition of malaria immunity. Several lines of evidence have indicated that antibodies against...... variant surface antigens (VSA) are important in the development of naturally acquired immunity to Plasmodium falciparum malaria and may thus be good indicators of immune status. We have compared the levels of VSA antibodies in plasma from children who have used ITN for 4 years to levels in plasma from...

  2. Improving Image Matching by Reducing Surface Reflections Using Polarising Filter Techniques

    Science.gov (United States)

    Conen, N.; Hastedt, H.; Kahmen, O.; Luhmann, T.

    2018-05-01

    In dense stereo matching applications surface reflections may lead to incorrect measurements and blunders in the resulting point cloud. To overcome the problem of disturbing reflexions polarising filters can be mounted on the camera lens and light source. Reflections in the images can be suppressed by crossing the polarising direction of the filters leading to homogeneous illuminated images and better matching results. However, the filter may influence the camera's orientation parameters as well as the measuring accuracy. To quantify these effects, a calibration and an accuracy analysis is conducted within a spatial test arrangement according to the German guideline VDI/VDE 2634.1 (2002) using a DSLR with and without polarising filter. In a second test, the interior orientation is analysed in more detail. The results do not show significant changes of the measuring accuracy in object space and only very small changes of the interior orientation (Δc ≤ 4 μm) with the polarising filter in use. Since in medical applications many tiny reflections are present and impede robust surface measurements, a prototypic trinocular endoscope is equipped with polarising technique. The interior and relative orientation is determined and analysed. The advantage of the polarising technique for medical image matching is shown in an experiment with a moistened pig kidney. The accuracy and completeness of the resulting point cloud can be improved clearly when using polarising filters. Furthermore, an accuracy analysis using a laser triangulation system is performed and the special reflection properties of metallic surfaces are presented.

  3. IMPROVING IMAGE MATCHING BY REDUCING SURFACE REFLECTIONS USING POLARISING FILTER TECHNIQUES

    Directory of Open Access Journals (Sweden)

    N. Conen

    2018-05-01

    Full Text Available In dense stereo matching applications surface reflections may lead to incorrect measurements and blunders in the resulting point cloud. To overcome the problem of disturbing reflexions polarising filters can be mounted on the camera lens and light source. Reflections in the images can be suppressed by crossing the polarising direction of the filters leading to homogeneous illuminated images and better matching results. However, the filter may influence the camera’s orientation parameters as well as the measuring accuracy. To quantify these effects, a calibration and an accuracy analysis is conducted within a spatial test arrangement according to the German guideline VDI/VDE 2634.1 (2002 using a DSLR with and without polarising filter. In a second test, the interior orientation is analysed in more detail. The results do not show significant changes of the measuring accuracy in object space and only very small changes of the interior orientation (Δc ≤ 4 μm with the polarising filter in use. Since in medical applications many tiny reflections are present and impede robust surface measurements, a prototypic trinocular endoscope is equipped with polarising technique. The interior and relative orientation is determined and analysed. The advantage of the polarising technique for medical image matching is shown in an experiment with a moistened pig kidney. The accuracy and completeness of the resulting point cloud can be improved clearly when using polarising filters. Furthermore, an accuracy analysis using a laser triangulation system is performed and the special reflection properties of metallic surfaces are presented.

  4. Surface Reduced CeO2 Nanowires for Direct Conversion of CO2 and Methanol to Dimethyl Carbonate: Catalytic Performance and Role of Oxygen Vacancy

    Directory of Open Access Journals (Sweden)

    Zhongwei Fu

    2018-04-01

    Full Text Available Ultralong 1D CeO2 nanowires were synthesized via an advanced solvothermal method, surface reduced under H2 atmosphere, and first applied in direct synthesis of dimethyl carbonate (DMC from CO2 and CH3OH. The micro morphologies, physical parameters of nanowires were fully investigated by transmission electron microscopy (TEM, X-ray diffraction (XRD, N2 adsorption, X-ray photoelectron spectrum (XPS, and temperature-programmed desorption of ammonia/carbon dioxide (NH3-TPD/CO2-TPD. The effects of surface oxygen vacancy and acidic/alkaline sites on the catalytic activity was explored. After reduction, the acidic/alkaline sites of CeO2 nanowires can be dramatically improved and evidently raised the catalytic performance. CeO2 nanowires reduced at 500 °C (CeO2_NW_500 exhibited notably superior activity with DMC yield of 16.85 mmol gcat−1. Furthermore, kinetic insights of initial rate were carried out and the apparent activation energy barrier of CeO2_NW_500 catalyst was found to be 41.9 kJ/mol, much tiny than that of CeO2_NW catalyst (74.7 KJ/mol.

  5. Understanding the creation of & reducing surface microroughness during polishing & post-processing of glass optics

    Energy Technology Data Exchange (ETDEWEB)

    Suratwala, Tayyab [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2016-09-22

    In the follow study, we have developed a detailed understanding of the chemical and mechanical microscopic interactions that occur during polishing affecting the resulting surface microroughness of the workpiece. Through targeted experiments and modeling, the quantitative relationships of many important polishing parameters & characteristics affecting surface microroughness have been determined. These behaviors and phenomena have been described by a number of models including: (a) the Ensemble Hertzian Multi Gap (EHMG) model used to predict the removal rate and roughness at atomic force microscope (AFM) scale lengths as a function of various polishing parameters, (b) the Island Distribution Gap (IDG) model used to predict the roughness at larger scale lengths, (c) the Deraguin-Verwey-Landau-Overbeek (DLVO) 3-body electrostatic colloidal model used to predict the interaction of slurry particles at the interface and roughness behavior as a function of pH, and (d) a diffusion/chemical reaction rate model of the incorporation of impurities species into the polishing surface layer (called the Bielby layer). Based on this improved understanding, novel strategies to polish the workpiece have been developed simultaneously leading to both ultrasmooth surfaces and high material removal rates. Some of these strategies include: (a) use of narrow PSD slurries, (b) a novel diamond conditioning recipe of the lap to increase the active contact area between the workpiece and lap without destroying its surface figure, (c) proper control of pH for a given glass type to allow for a uniform distribution of slurry particles at the interface, and (d) increase in applied load just up to the transition between molecular to plastic removal regime for a single slurry particle. These techniques have been incorporated into a previously developed finishing process called Convergent Polishing leading to not just economical finishing process with improved surface figure control, but also

  6. Momentos do parque em uma rotina de educação infantil: corpo, consumo, barbárie Playground moments in an early childhood education routine: body, consumption and barbarism

    Directory of Open Access Journals (Sweden)

    Ana Cristina Richter

    2010-12-01

    routine comprising various moments: arrival, cleaning, feeding, sleep, playground, guided activity, departure. Inspired by issues from the Critical Theory of Society, the present text deals with the playground moments, considered as "privileged situations for education", both in the teachers' discourses and in the actions that distinguish these moments from the others, establishing a kind of opposition between "work time" and "free time". In such relation, apart from being regarded as periods to renew energies for the other activities, these moments offer an excuse to suspend the closer following up of activities by the teachers: the look of the grown up "will need" only to steer children clear of inadequate places or to avoid "exposed" wounds, shaping a group of socio-sanitary practices around the vital needs, and that contribute to eliminate deviances and differences in pursuit of pseudo-gratifications. The absence of a more careful approximation will also leave children to an ambiguous "spontaneity", subjected to the violence that produces scars, mainly on the body, and which promote the kind of education that privileges barbarism instead of opposing it. The results show also the presence of products for the consumption of leisure that inform beforehand the sequence of operations to be reproduced, requiring automated gestures and actions that stimulate the barrenness of imagination.

  7. Research for Actively Reducing Infrared Radiation by Thermoelectric Refrigerator

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Hoon; Kim, Kyomin; Kim, Woochul [Yonsei Univ., Seoul (Korea, Republic of)

    2017-03-15

    We introduced a technology for reducing infrared radiation through the active cooling of hot surfaces by using a thermoelectric refrigerator. Certain surfaces were heated by aerodynamic heating, and the heat generation processes are proposed here. We calculated the temperatures and radiations from surfaces, while using thermoelectric refrigerators to cool the surfaces. The results showed that the contrast between the radiations of certain surfaces and the ambient environments can be removed using thermoelectric refrigerators.

  8. Reducing Escherichia coli growth on a composite biomaterial by a surface immobilized antimicrobial peptide

    Energy Technology Data Exchange (ETDEWEB)

    Buckholtz, Gavin A.; Reger, Nina A. [Department of Chemistry and Biochemistry, Duquesne University, Pittsburgh, PA 15282 (United States); Anderton, William D.; Schimoler, Patrick J. [Orthopaedic Biomechanics Research Laboratory, Allegheny General Hospital, Pittsburgh, PA 15212 (United States); Roudebush, Shana L.; Meng, Wilson S. [Division of Pharmaceutical Sciences, Duquesne University, Pittsburgh, PA 15282 (United States); Miller, Mark C. [Orthopaedic Biomechanics Research Laboratory, Allegheny General Hospital, Pittsburgh, PA 15212 (United States); Gawalt, Ellen S., E-mail: gawalte@duq.edu [Department of Chemistry and Biochemistry, Duquesne University, Pittsburgh, PA 15282 (United States); McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA 15219 (United States)

    2016-08-01

    A new composite bioceramic consisting of calcium aluminum oxide (CaAlO) and hydroxyapatite (HA) was functionalized with the synthetic antimicrobial peptide Inverso-CysHHC10. CaAlO is a bioceramic that can be mold cast easily and quickly at room temperature. Improved functionality was previously achieved through surface reactions. Here, composites containing 0–5% HA (by mass) were prepared and the elastic modulus and modulus of rupture were mechanically similar to non-load bearing bone. The addition of hydroxyapatite resulted in increased osteoblast attachment (> 180%) and proliferation (> 140%) on all composites compared to 100% CaAlO. Antimicrobial peptide (AMP) immobilization was achieved using an interfacial alkene-thiol click reaction. The linked AMP persisted on the composite (> 99.6% after 24 h) and retained its activity against Escherichia coli based on N-phenylnaphthylamine uptake and bacterial turbidity tests. Overall, this simple scaffold system improves osteoblast activity and reduces bacterial activity. - Highlights: • Calcium aluminum oxide and hydroxyapatite were cast into a composite material. • Osteoblast attachment and proliferation were significantly increased on composites. • An active antimicrobial peptide was linked to and remained stable on the composite. • Bacterial turbidity and NPN uptake tests showed modified composites had an effect equal to a 10 μM Inverso-CysHHC10 solution. • Antimicrobial peptide linkage did not affect the increased osteoblast performance.

  9. Reducing Escherichia coli growth on a composite biomaterial by a surface immobilized antimicrobial peptide

    International Nuclear Information System (INIS)

    Buckholtz, Gavin A.; Reger, Nina A.; Anderton, William D.; Schimoler, Patrick J.; Roudebush, Shana L.; Meng, Wilson S.; Miller, Mark C.; Gawalt, Ellen S.

    2016-01-01

    A new composite bioceramic consisting of calcium aluminum oxide (CaAlO) and hydroxyapatite (HA) was functionalized with the synthetic antimicrobial peptide Inverso-CysHHC10. CaAlO is a bioceramic that can be mold cast easily and quickly at room temperature. Improved functionality was previously achieved through surface reactions. Here, composites containing 0–5% HA (by mass) were prepared and the elastic modulus and modulus of rupture were mechanically similar to non-load bearing bone. The addition of hydroxyapatite resulted in increased osteoblast attachment (> 180%) and proliferation (> 140%) on all composites compared to 100% CaAlO. Antimicrobial peptide (AMP) immobilization was achieved using an interfacial alkene-thiol click reaction. The linked AMP persisted on the composite (> 99.6% after 24 h) and retained its activity against Escherichia coli based on N-phenylnaphthylamine uptake and bacterial turbidity tests. Overall, this simple scaffold system improves osteoblast activity and reduces bacterial activity. - Highlights: • Calcium aluminum oxide and hydroxyapatite were cast into a composite material. • Osteoblast attachment and proliferation were significantly increased on composites. • An active antimicrobial peptide was linked to and remained stable on the composite. • Bacterial turbidity and NPN uptake tests showed modified composites had an effect equal to a 10 μM Inverso-CysHHC10 solution. • Antimicrobial peptide linkage did not affect the increased osteoblast performance.

  10. Chameleon Coatings: Adaptive Surfaces to Reduce Friction and Wear in Extreme Environments

    Science.gov (United States)

    Muratore, C.; Voevodin, A. A.

    2009-08-01

    Adaptive nanocomposite coating materials that automatically and reversibly adjust their surface composition and morphology via multiple mechanisms are a promising development for the reduction of friction and wear over broad ranges of ambient conditions encountered in aerospace applications, such as cycling of temperature and atmospheric composition. Materials selection for these composites is based on extensive study of interactions occurring between solid lubricants and their surroundings, especially with novel in situ surface characterization techniques used to identify adaptive behavior on size scales ranging from 10-10 to 10-4 m. Recent insights on operative solid-lubricant mechanisms and their dependency upon the ambient environment are reviewed as a basis for a discussion of the state of the art in solid-lubricant materials.

  11. Occurrence of sulphate reducing bacteria (SRB associated with biocorrosion on metallic surfaces in a hydroelectric power station in Ibirama (SC - Brazil

    Directory of Open Access Journals (Sweden)

    Paulo Roberto Dantas Marangoni

    2013-10-01

    Full Text Available The aim of this study was evaluate, two methods for the detection and identification of sulphate reducing bacteria (SRB: ML medium and PCR with specific primers for SRB groups. SRB were detected through the selective medium only on carbon steel, which showed corrosion. Employing specific PCR primer, SBR were detected from all the metallic components assayed, even those that did not present visible corrosion spots, such stainless steel and copper alloys. Despite the presence or absence of corrosion at the later stages effectively by using the selective medium,, the initial stages of the corrosion could only be detected by the amplification of total DNA with SRB specific primers. The early detection of SRB could be employed for preventing the damages on metal surfaces before the installation of corrosion processes. Strategies for reducing the time spent on SRB isolation and identification could be auxiliary tools for controlling the corrosion of materials.

  12. PREFACE: Vibrations at surfaces Vibrations at surfaces

    Science.gov (United States)

    Rahman, Talat S.

    2011-12-01

    This special issue is dedicated to the phenomenon of vibrations at surfaces—a topic that was indispensible a couple of decades ago, since it was one of the few phenomena capable of revealing the nature of binding at solid surfaces. For clean surfaces, the frequencies of modes with characteristic displacement patterns revealed how surface geometry, as well as the nature of binding between atoms in the surface layers, could be different from that in the bulk solid. Dispersion of the surface phonons provided further measures of interatomic interactions. For chemisorbed molecules on surfaces, frequencies and dispersion of the vibrational modes were also critical for determining adsorption sites. In other words, vibrations at surfaces served as a reliable means of extracting information about surface structure, chemisorption and overlayer formation. Experimental techniques, such as electron energy loss spectroscopy and helium-atom-surface scattering, coupled with infra-red spectroscopy, were continually refined and their resolutions enhanced to capture subtleties in the dynamics of atoms and molecules at surfaces. Theoretical methods, whether based on empirical and semi-empirical interatomic potential or on ab initio electronic structure calculations, helped decipher experimental observations and provide deeper insights into the nature of the bond between atoms and molecules in regions of reduced symmetry, as encountered on solid surfaces. Vibrations at surfaces were thus an integral part of the set of phenomena that characterized surface science. Dedicated workshops and conferences were held to explore the variety of interesting and puzzling features revealed in experimental and theoretical investigations of surface vibrational modes and their dispersion. One such conference, Vibrations at Surfaces, first organized by Harald Ibach in Juelich in 1980, continues to this day. The 13th International Conference on Vibrations at Surfaces was held at the University of

  13. Radioactive contamination status of an elementary school in southern Miyagi Prefecture, Japan, four years after decontamination

    International Nuclear Information System (INIS)

    Yamaguchi, Toshiro; Sato, Mitsuyoshi; Nagakubo, Kazuyoshi

    2017-01-01

    We investigated the radioactive contamination status of an elementary school in southern Miyagi Prefecture, Japan, four years after decontamination. The radioactive dose rate was measured in the playground (n = 36), back yard (n = 1), parking lot (n = 3), and gutters (n = 30) with a thallium-activated sodium iodide scintillation detector. In addition, topsoil from the playground and gutters sediment were measured with a high-purity germanium semiconductor detector, and sand from the parking lot and sediment from gutters was imaged following an autoradiography method. The mean radioactive dose rate in the playground was almost 0.08 μSv/h. The dose rate was higher at sites facing the mountains, near the main gate, and by the front entrance of the school building. Meanwhile, the radioactive cesium (Cs) concentration of sediment imaged using autoradiography was > 8,000 Bq/kg. These results indicated that the radioactive dose rates in the decontaminated school were below the threshold for being a health hazard. However, the topsoil in the playground had been re-contaminated with radioactive Cs, which had likely been transported via dirt attached to children's shoes and car tires. In addition, the radioactive sediment in the gutters had likely been contaminated by rainwater, suggesting that radioactive protection is necessary when handling gutter sediment. (author)

  14. HybridPLAY: A New Technology to Foster Outdoors Physical Activity, Verbal Communication and Teamwork.

    Science.gov (United States)

    Díaz, Diego José; Boj, Clara; Portalés, Cristina

    2016-04-23

    This paper presents HybridPLAY, a novel technology composed of a sensor and mobile-based video games that transforms urban playgrounds into game scenarios. With this technology we aim to stimulate physical activity and playful learning by creating an entertaining environment in which users can actively participate and collaborate. HybridPLAY is different from other existing technologies that enhance playgrounds, as it is not integrated in them but can be attached to the different elements of the playgrounds, making its use more ubiquitous (i.e., not restricted to the playgrounds). HybridPLAY was born in 2007 as an artistic concept, and evolved after different phases of research and testing by almost 2000 users around the world (in workshops, artistic events, conferences, etc.). Here, we present the temporal evolution of HybridPLAY with the different versions of the sensors and the video games, and a detailed technical description of the sensors and the way interactions are produced. We also present the outcomes after the evaluation by users at different events and workshops. We believe that HybridPLAY has great potential to contribute to increased physical activity in kids, and also to improve the learning process and monitoring at school centres by letting users create the content of the apps, leading to new narratives and fostering creativity.

  15. Dynamic Dispersal of Surface Layer Biofilm Induced by Nanosized TiO2 Based on Surface Plasmon Resonance and Waveguide.

    Science.gov (United States)

    Zhang, Peng; Guo, Jin-Song; Yan, Peng; Chen, You-Peng; Wang, Wei; Dai, You-Zhi; Fang, Fang; Wang, Gui-Xue; Shen, Yu

    2018-05-01

    Pollutant degradation is present mainly in the surface layer of biofilms, and the surface layer is the most vulnerable to impairment by toxic pollutants. In this work, the effects of nanosized TiO 2 (n-TiO 2 ) on the average thicknesses of Bacillus subtilis biofilm and on bacterial attachment on different surfaces were investigated. The binding mechanism of n-TiO 2 to the cell surface was also probed. The results revealed that n-TiO 2 caused biofilm dispersal and the thicknesses decreased by 2.0 to 2.6 μm after several hours of exposure. The attachment abilities of bacteria with extracellular polymeric substances (EPS) on hydrophilic surfaces were significantly reduced by 31% and 81% under 10 and 100 mg/liter of n-TiO 2 , respectively, whereas those of bacteria without EPS were significantly reduced by 43% and 87%, respectively. The attachment abilities of bacteria with and without EPS on hydrophobic surfaces were significantly reduced by 50% and 56%, respectively, under 100 mg/liter of n-TiO 2 The results demonstrated that biofilm dispersal can be attributed to the changes in the cell surface structure and the reduction of microbial attachment ability. IMPORTANCE Nanoparticles can penetrate into the outer layer of biofilm in a relatively short period and can bind onto EPS and bacterial surfaces. The current work probed the effects of nanosized TiO 2 (n-TiO 2 ) on biofilm thickness, bacterial migration, and surface properties of the cell in the early stage using the surface plasmon resonance waveguide mode. The results demonstrated that n-TiO 2 decreased the adhesive ability of both cell and EPS and induced bacterial migration and biofilm detachment in several hours. The decreased adhesive ability of microbes and EPS worked against microbial aggregation, reducing the effluent quality in the biological wastewater treatment process. Copyright © 2018 American Society for Microbiology.

  16. The effect of surface characteristics of reduced graphene oxide on the performance of a pseudocapacitor

    International Nuclear Information System (INIS)

    Chang, M S; Kim, T; Kang, J H; Park, J; Park, C R

    2015-01-01

    In this research, we have analyzed the electrochemical characteristics of the different rGO/Co 3 O 4 composites prepared by controlling the rGO surface characteristics and its relationship between the growth of Co 3 O 4 nanoparticles and the performance of the pseudocapacitor. Reduced graphene oxide/cobalt oxide (rGO/Co 3 O 4 ) nanocomposites of different morphologies were prepared through the simple hydrothermal method. First, different kinds of graphite precursors, crumpled and planar with different properties, were used to determine the most suitable substrate to grow Co 3 O 4 nanoparticles. As a result, rGO/Co 3 O 4 composite synthesized from planar graphite shows a higher specific capacitance of 207.2, 170.1, and 141.5 Fg −1 at 1, 2, and 5 Ag −1 than the one prepared from crumpled graphite. In the second part, planar graphite, confirmed to be the most suitable substrate from the previous part, was oxidized under various oxidation conditions to increase the oxygen functional groups attached on the GO surfaces and observed to see how it affects the growth of Co 3 O 4 nanoparticles and its influence on the electrochemical performance of the rGO/Co 3 O 4 pseudocapacitor. As a result, the one with the largest amount of functional groups had the Co 3 O 4 nanoparticles well dispersed and grown on the rGO substrate in small nanoparticle sizes, as small as 5.9 nm, leading to an improved electrochemical performance. Thus, the specific capacitance with the least amount of oxygen functional groups are 207.2, 170.1, and 141.5 Fg −1 and for the largest amount of functional groups are 411.5, 371.4, and 292.7 Fg −1 , at 1, 2, and 5 Ag −1 respectively. This approach could become a guideline for the ideal fabrication of rGO/metal oxide composite for further research involving rGO based pseudocapacitors. (paper)

  17. Arsenic levels in wipe samples collected from play structures constructed with CCA-treated wood: Impact on exposure estimates

    Energy Technology Data Exchange (ETDEWEB)

    Barraj, Leila M. [Chemical Regulation and Food Safety, Exponent, Inc., Suite 1100, 1150 Connecticut Ave., NW, Washington, DC 20036 (United States)], E-mail: lbarraj@exponent.com; Scrafford, Carolyn G. [Chemical Regulation and Food Safety, Exponent, Inc., Suite 1100, 1150 Connecticut Ave., NW, Washington, DC 20036 (United States); Eaton, W. Cary [RTI International, 3040 Cornwallis Road, Research Triangle Park, NC 27709 (United States); Rogers, Robert E.; Jeng, Chwen-Jyh [Toxcon Health Sciences Research Centre Inc., 9607 - 41 Avenue, Edmonton, Alberta, T6E 5X7 (Canada)

    2009-04-01

    Lumber treated with chromated copper arsenate (CCA) has been used in residential outdoor wood structures and playgrounds. The U.S. EPA has conducted a probabilistic assessment of children's exposure to arsenic from CCA-treated structures using the Stochastic Human Exposure and Dose Simulation model for the wood preservative scenario (SHEDS-Wood). The EPA assessment relied on data from an experimental study using adult volunteers and designed to measure arsenic in maximum hand and wipe loadings. Analyses using arsenic handloading data from a study of children playing on CCA-treated play structures in Edmonton, Canada, indicate that the maximum handloading values significantly overestimate the exposure that occurs during actual play. The objective of our paper is to assess whether the dislodgeable arsenic residues from structures in the Edmonton study are comparable to those observed in other studies and whether they support the conclusion that the values derived by EPA using modeled maximum loading values overestimate hand exposures. We compared dislodgeable arsenic residue data from structures in the playgrounds in the Edmonton study to levels observed in studies used in EPA's assessment. Our analysis showed that the dislodgeable arsenic levels in the Edmonton playground structures are similar to those in the studies used by EPA. Hence, the exposure estimates derived using the handloading data from children playing on CCA-treated structures are more representative of children's actual exposures than the overestimates derived by EPA using modeled maximum values. Handloading data from children playing on CCA-treated structures should be used to reduce the uncertainty of modeled estimates derived using the SHEDS-Wood model.

  18. Modification of BSCCO surface by excimer laser annealing

    International Nuclear Information System (INIS)

    Ibi, A.; Akitsu, T.; Matsuzawa, H.

    2002-01-01

    Irradiation of Kr-F excimer laser onto the BSCCO calcined pellets changed their surface to be amorphous. SEM micrographs showed that sintering of the irradiated pellets recrystallized the surface layer and much reduced the intergrain gaps as compared with only sintered pellets, whereas the internal structure of the irradiated pellets remained unchanged. This processing made the surface-layer grains be tightly connected, resulting in the higher critical temperature than the conventionally sintered samples. We can say that excimer laser annealing process is a novel scheme to reduce the surface weak-link of the high Tc superconductors. (author)

  19. Polymer Coatings Reduce Electro-osmosis

    Science.gov (United States)

    Herren, Blair J.; Snyder, Robert; Shafer, Steven G.; Harris, J. Milton; Van Alstine, James M.

    1989-01-01

    Poly(ethylene glycol) film controls electrostatic potential. Electro-osmosis in quartz or glass chambers reduced or reversed by coating inside surface of chambers with monomacromolecular layers of poly(ethylene glycol). Stable over long times. Electrostatic potential across surface of untreated glass or plastic chamber used in electro-phoresis is negative and attracts cations in aqueous electrolyte. Cations solvated, entrains flow of electrolyte migrating toward cathode. Electro-osmotic flow interferes with desired electrophoresis of particles suspended in electrolyte. Polymer coats nontoxic, transparent, and neutral, advantageous for use in electrophoresis.

  20. Polymer multilayers loaded with antifungal β-peptides kill planktonic Candida albicans and reduce formation of fungal biofilms on the surfaces of flexible catheter tubes.

    Science.gov (United States)

    Raman, Namrata; Lee, Myung-Ryul; Palecek, Sean P; Lynn, David M

    2014-10-10

    Candida albicans is the most common fungal pathogen responsible for hospital-acquired infections. Most C. albicans infections are associated with the implantation of medical devices that act as points of entry for the pathogen and as substrates for the growth of fungal biofilms that are notoriously difficult to eliminate by systemic administration of conventional antifungal agents. In this study, we report a fill-and-purge approach to the layer-by-layer fabrication of biocompatible, nanoscale 'polyelectrolyte multilayers' (PEMs) on the luminal surfaces of flexible catheters, and an investigation of this platform for the localized, intraluminal release of a cationic β-peptide-based antifungal agent. We demonstrate that polyethylene catheter tubes with luminal surfaces coated with multilayers ~700nm thick fabricated from poly-l-glutamic acid (PGA) and poly-l-lysine (PLL) can be loaded, post-fabrication, by infusion with β-peptide, and that this approach promotes extended intraluminal release of this agent (over ~4months) when incubated in physiological media. The β-peptide remained potent against intraluminal inoculation of the catheters with C. albicans and substantially reduced the formation of C. albicans biofilms on the inner surfaces of film-coated catheters. Finally, we report that these β-peptide-loaded coatings exhibit antifungal activity under conditions that simulate intermittent catheter use and microbial challenge for at least three weeks. We conclude that β-peptide-loaded PEMs offer a novel and promising approach to kill C. albicans and prevent fungal biofilm formation on surfaces, with the potential to substantially reduce the incidence of device-associated infections in indwelling catheters. β-Peptides comprise a promising new class of antifungal agents that could help address problems associated with the use of conventional antifungal agents. The versatility of the layer-by-layer approach used here thus suggests additional opportunities to

  1. Efficacy of humidity retention bags for the reduced adsorption and improved cleaning of tissue proteins including prion-associated amyloid to surgical stainless steel surfaces.

    Science.gov (United States)

    Secker, T J; Pinchin, H E; Hervé, R C; Keevil, C W

    2015-01-01

    Increasing drying time adversely affects attachment of tissue proteins and prion-associated amyloid to surgical stainless steel, and reduces the efficacy of commercial cleaning chemistries. This study tested the efficacy of commercial humidity retention bags to reduce biofouling on surgical stainless steel and to improve subsequent cleaning. Surgical stainless steel surfaces were contaminated with ME7-infected brain homogenates and left to dry for 15 to 1,440 min either in air, in dry polythene bags or within humidity retention bags. Residual contamination pre/post cleaning was analysed using Thioflavin T/SYPRO Ruby dual staining and microscope analysis. An increase in biofouling was observed with increased drying time in air or in sealed dry bags. Humidity retention bags kept both protein and prion-associated amyloid minimal across the drying times both pre- and post-cleaning. Therefore, humidity bags demonstrate a cheap, easy to implement solution to improve surgical instrument reprocessing and to potentially reduce associated hospital acquired infections.

  2. Warming Early Mars by Impact Degassing of Reduced Greenhouse Gases

    Science.gov (United States)

    Haberle, R. M.; Zahnle, K.; Barlow, N. G.

    2018-01-01

    Reducing greenhouse gases are once again the latest trend in finding solutions to the early Mars climate dilemma. In its current form collision induced absorptions (CIA) involving H2 and/or CH4 provide enough extra greenhouse power in a predominately CO2 atmosphere to raise global mean surface temperatures to the melting point of water provided the atmosphere is thick enough and the reduced gases are abundant enough. Surface pressures must be at least 500 mb and H2 and/or CH4 concentrations must be at or above the several percent level for CIA to be effective. Atmospheres with 1-2 bars of CO2 and 2- 10% H2 can sustain surface environments favorable for liquid water. Smaller concentrations of H2 are sufficient if CH4 is also present. If thick CO2 atmospheres with percent level concentrations of reduced gases are the solution to the faint young Sun paradox for Mars, then plausible mechanisms must be found to generate and sustain the gases. Possible sources of reducing gases include volcanic outgassing, serpentinization, and impact delivery; sinks include photolyis, oxidation, and escape to space. The viability of the reduced greenhouse hypothesis depends, therefore, on the strength of these sources and sinks. In this paper we focus on impact delivered reduced gases.

  3. Enhancement of Friction against a Rough Surface by a Ridge-Channel Surface Microstructure.

    Science.gov (United States)

    Bai, Ying; Hui, Chung-Yuen; Levrard, Benjamin; Jagota, Anand

    2015-07-14

    We report on a study of the sliding friction of elastomeric surfaces patterned with ridges and channels (and unstructured flat controls), against both smooth and roughened spherical indenters. Against the smooth spherical indenter, all of the structured surfaces have highly reduced sliding friction due to the reduction in actual area of contact. Against roughened spherical indenters, however, the sliding force for structured samples can be up to 50% greater than that of an unstructured flat control. The mechanism of enhanced friction against a rough surface is due to a combination of increased actual area of contact, interlocking between roughness and the surface structure, and attendant dynamic instabilities that dissipate energy.

  4. Impact Delivery of Reduced Greenhouse Gases on Early Mars

    Science.gov (United States)

    Haberle, R. M.; Zahnle, K. J.; Barlow, N. G.

    2017-12-01

    Reducing greenhouse gases are the latest trend in finding solutions to the early Mars climate dilemma. In thick CO2 atmospheres with modest concentrations of H2 and/or CH4, collision induced absorptions can reduce the outgoing long wave radiation enough to provide a significant greenhouse effect. To raise surface temperatures significantly by this process, surface pressures must be at least 500 mb and H2 and/or CH4 concentrations must be at or above the several percent level. Volcanism, serpentinization, and impacts are possible sources for reduced gases. Here we investigate the delivery of such gases by impact degassing from comets and asteroids. We use a time-marching stochastic impactor model that reproduces the observed crater size frequency distribution of Noachian surfaces. Following each impact, reduced gases are added to the atmosphere from a production function based on gas equilibrium calculations for several classes of meteorites and comets at typical post-impact temperatures. Escape and photochemistry then remove the reduced greenhouse gases continuously in time throughout each simulation. We then conduct an ensemble of simulations with this simple model varying the surface pressure, impact history, reduced gas production and escape functions, and mix of impactor types, to determine if this could be a potentially important part of the early Mars story. Our goal is to determine the duration of impact events that elevate reduced gas concentrations to significant levels and the total time of such events throughout the Noachian. Our initial simulations indicate that large impactors can raise H2 concentrations above the 10% level - a level high enough for a very strong greenhouse effect in a 1 bar CO2 atmosphere - for millions of years, and that the total time spent at or above that level can be in the 10's of millions of years range. These are interesting results that we plan to explore more thoroughly for the meeting.

  5. Drag-reducing performance of obliquely aligned superhydrophobic surface in turbulent channel flow

    Energy Technology Data Exchange (ETDEWEB)

    Watanabe, Sho; Fukagata, Koji [Department of Mechanical Engineering, Keio University, Hiyoshi 3-14-1, Kohoku-ku, Yokohama 223-8522 (Japan); Mamori, Hiroya, E-mail: fukagata@mech.keio.ac.jp [Department of Mechanical Engineering, Tokyo University of Science, Niijuku 6-3-1, Katsushika-ku, Tokyo 125-8585 (Japan)

    2017-04-15

    Friction drag reduction effect by superhydrophobic surfaces in a turbulent channel flow is investigated by means of direct numerical simulation. The simulations are performed under a constant pressure gradient at the friction Reynolds number of 180. A special focus is laid upon the influence of the angle of microridge structure to flow direction, while the gas area fraction on the surface is kept at 50% and the groove width is kept constant at 33.75 wall units. Larger drag reduction effect is observed for a smaller angle: the bulk-mean velocity is increased about 15% when the microridge is parallel to the flow. The drag reduction effect is found to deteriorate rapidly with the microridge angle due to a decrease in the slip velocity. The Reynolds stress budgets show that the modification in each physical effect is qualitatively similar but more pronounced when the microridge is aligned with the stream. (paper)

  6. Surface roughening of undoped and in situ B-doped SiGe epitaxial layers deposited by using reduced pressure chemical vapor deposition

    Science.gov (United States)

    Kim, Youngmo; Park, Jiwoo; Sohn, Hyunchul

    2018-01-01

    Si1- x Ge x (:B) epitaxial layers were deposited by using reduced pressure chemical vapor deposition with SiH4, GeH4, and B2H6 source gases, and the dependences of the surface roughness of undoped Si1- x Ge x on the GeH4 flow rate and of Si1- x Ge x :B on the B2H6 flow rate were investigated. The root-mean-square (RMS) roughness value of the undoped Si1- x Ge x at constant thickness increased gradually with increasing Ge composition, resulting from an increase in the amplitude of the wavy surface before defect formation. At higher Ge compositions, the residual strain in Si1- x Ge x significantly decreased through the formation of defects along with an abrupt increase in the RMS roughness. The variation of the surface roughness of Si1- x Ge x :B depended on the boron (B) concentration. At low B concentrations, the RMS roughness of Si1- x Ge x remained constant regardless of Ge composition, which is similar to that of undoped Si1- x Ge x . However, at high B concentrations, the RMS roughness of Si1- x Ge x :B increased greatly due to B islanding. In addition, at very high B concentrations ( 9.9 at%), the RMS roughness of Si1- x Ge x :B decreased due to non-epitaxial growth.

  7. Surface contact fatigue failures in gears

    CSIR Research Space (South Africa)

    Fernandes, PJL

    1997-06-01

    Full Text Available Surface contact fatigue is the most common cause of gear failure. It results in damage to contacting surfaces which can significantly reduce the load-carrying capacity of components, and may ultimately lead to complete failure of a gear. Three types...

  8. Objective Measures of the Built Environment and Physical Activity in Children

    DEFF Research Database (Denmark)

    Buck, Christoph; Tkaczick, Tobias; Pitsiladis, Yannis

    2015-01-01

    on MVPA, while land use mix revealed a negative effect on MVPA (βˆ=−0.173,p=0.13) . In particular, playground density (βˆ=0.048,p=0.01) and density of public open spaces, i.e., playgrounds and parks combined (βˆ=0.040,p=0.01) , showed positive effects on MVPA. However, availability of green spaces showed...... on individual network-dependent neighborhoods. Environmental features of the walkability concept and the availability of recreational facilities, i.e. playgrounds, green spaces, and parks, were measured. Relevant features were combined to a moveability index that should capture urban opportunities for PA...... open space density (βˆ=0.014,p=0.007) , but no effects of urban measures and moveability indices were found in pre-school children. The final moveability indices capture relevant opportunities for PA in school children. Particularly, availability of public open spaces seems to be a strong predictor...

  9. Power-Up: Exploration and Play in a Novel Modified Ride-On Car for Standing.

    Science.gov (United States)

    Logan, Samuel W; Lobo, Michele A; Feldner, Heather A; Schreiber, Melynda; MacDonald, Megan; Winden, Haylee N; Stoner, Tracy; Galloway, James Cole

    2017-01-01

    The purpose of this study was to compare the physical activity and play behaviors of preschoolers without disabilities and 1 preschooler with physical disability. Participants were 42 preschoolers without disabilities and 1 preschooler with physical disability (Child A). Child A used either crutches or a modified ride-on car while in the gymnasium and playground. In the gymnasium, Child A engaged in less solitary play and more parallel play while using the modified ride-on car compared with crutches. On the playground, Child A engaged in more sitting and less running while using crutches compared with preschoolers without disabilities. On the playground, Child A engaged in more peer interaction and less teacher interaction when using the modified ride-on car compared with crutches. For children with disabilities who may use assistive devices, clinicians, families, and teachers are encouraged to embrace a "right device, right time, right place" approach.

  10. New Material Development for Surface Layer and Surface Technology in Tribology Science to Improve Energy Efficiency

    International Nuclear Information System (INIS)

    Ismail, R.; Tauviqirrahman, M.; Jamari; Schipper, D. J.

    2009-01-01

    This paper reviews the development of new material and surface technology in tribology and its contribution to energy efficiency. Two examples of the economic benefits, resulted from the optimum tribology in the transportation sector and the manufacturing industry are discussed. The new materials are proposed to modify the surface property by laminating the bulk material with thin layer/coating. Under a suitable condition, the thin layer on a surface can provide a combination of good wear, a low friction and corrosion resistance for the mechanical components. The innovation in layer technology results molybdenum disulfide (MoS2), diamond like carbon (DLC), cubic boron nitride (CBN) and diamond which perform satisfactory outcome. The application of the metallic coatings to carbon fibre reinforced polymer matrix composites (CFRP) has the capacity to provide considerable weight and power savings for many engineering components. The green material for lubricant and additives such as the use of sunflower oil which possesses good oxidation resistance and the use of mallee leaves as bio‐degradable solvent are used to answer the demand of the environmentally friendly material with good performance. The tribology research implementation for energy efficiency also touches the simple things around us such as: erasing the laser‐print in a paper with different abrasion techniques. For the technology in the engineering surface, the consideration for generating the suitable surface of the components in running‐in period has been discussed in order to prolong the components life and reduce the machine downtime. The conclusion, tribology can result in reducing manufacturing time, reducing the maintenance requirements, prolonging the service interval, improving durability, reliability and mechanical components life, and reducing harmful exhaust emission and waste. All of these advantages will increase the energy efficiency and the economic benefits.

  11. New Material Development for Surface Layer and Surface Technology in Tribology Science to Improve Energy Efficiency

    Science.gov (United States)

    Ismail, R.; Tauviqirrahman, M.; Jamari, Jamari; Schipper, D. J.

    2009-09-01

    This paper reviews the development of new material and surface technology in tribology and its contribution to energy efficiency. Two examples of the economic benefits, resulted from the optimum tribology in the transportation sector and the manufacturing industry are discussed. The new materials are proposed to modify the surface property by laminating the bulk material with thin layer/coating. Under a suitable condition, the thin layer on a surface can provide a combination of good wear, a low friction and corrosion resistance for the mechanical components. The innovation in layer technology results molybdenum disulfide (MoS2), diamond like carbon (DLC), cubic boron nitride (CBN) and diamond which perform satisfactory outcome. The application of the metallic coatings to carbon fibre reinforced polymer matrix composites (CFRP) has the capacity to provide considerable weight and power savings for many engineering components. The green material for lubricant and additives such as the use of sunflower oil which possesses good oxidation resistance and the use of mallee leaves as bio-degradable solvent are used to answer the demand of the environmentally friendly material with good performance. The tribology research implementation for energy efficiency also touches the simple things around us such as: erasing the laser-print in a paper with different abrasion techniques. For the technology in the engineering surface, the consideration for generating the suitable surface of the components in running-in period has been discussed in order to prolong the components life and reduce the machine downtime. The conclusion, tribology can result in reducing manufacturing time, reducing the maintenance requirements, prolonging the service interval, improving durability, reliability and mechanical components life, and reducing harmful exhaust emission and waste. All of these advantages will increase the energy efficiency and the economic benefits.

  12. Conhecimento histórico e crianças pequenas: parques infantis e escola municipal de educação infantil Historical knowledge and small children: children's playgrounds and the state's primary education

    Directory of Open Access Journals (Sweden)

    Marcia Aparecida Gobbi

    2012-06-01

    Full Text Available Este artigo relata a experiência com o projeto "Os parques infantis de Mário de Andrade ontem e hoje", empreendido por todos os profissionais e crianças de uma escola municipal de Educação Infantil da cidade de São Paulo. A preocupação com o conhecimento histórico e as crianças da primeira infância e suas especificidades, numa perspectiva não-escolarizante e não-antecipatória do Ensino Fundamental, foi a tônica e um desafio. Procura aliar história e memória, estabelecendo relações entre História da Educação, história da escolarização de crianças pequenas e formação docente.This article discusses an experience with the project "The children's playgrounds of Mario de Andrade, yesterday and today", undertaken by all the professionals and children of a state primary school in the city of São Paulo. The concern with historical knowledge and the children in the first years of primary school, with their specific qualities, their un-schooled perspective and their inability to predict the school's teaching approach, was the keynote of this study and the challenge faced. A link between history and memory is sought, establishing a relationship between the History of Education, the history of small children being schooled and teacher training.

  13. Nitride surface passivation of GaAs nanowires: impact on surface state density.

    Science.gov (United States)

    Alekseev, Prokhor A; Dunaevskiy, Mikhail S; Ulin, Vladimir P; Lvova, Tatiana V; Filatov, Dmitriy O; Nezhdanov, Alexey V; Mashin, Aleksander I; Berkovits, Vladimir L

    2015-01-14

    Surface nitridation by hydrazine-sulfide solution, which is known to produce surface passivation of GaAs crystals, was applied to GaAs nanowires (NWs). We studied the effect of nitridation on conductivity and microphotoluminescence (μ-PL) of individual GaAs NWs using conductive atomic force microscopy (CAFM) and confocal luminescent microscopy (CLM), respectively. Nitridation is found to produce an essential increase in the NW conductivity and the μ-PL intensity as well evidence of surface passivation. Estimations show that the nitride passivation reduces the surface state density by a factor of 6, which is of the same order as that found for GaAs/AlGaAs nanowires. The effects of the nitride passivation are also stable under atmospheric ambient conditions for six months.

  14. Visual Information and Support Surface for Postural Control in Visual Search Task.

    Science.gov (United States)

    Huang, Chia-Chun; Yang, Chih-Mei

    2016-10-01

    When standing on a reduced support surface, people increase their reliance on visual information to control posture. This assertion was tested in the current study. The effects of imposed motion and support surface on postural control during visual search were investigated. Twelve participants (aged 21 ± 1.8 years; six men and six women) stood on a reduced support surface (45% base of support). In a room that moved back and forth along the anteroposterior axis, participants performed visual search for a given letter in an article. Postural sway variability and head-room coupling were measured. The results of head-room coupling, but not postural sway, supported the assertion that people increase reliance on visual information when standing on a reduced support surface. Whether standing on a whole or reduced surface, people stabilized their posture to perform the visual search tasks. Compared to a fixed target, searching on a hand-held target showed greater head-room coupling when standing on a reduced surface. © The Author(s) 2016.

  15. The estimation of dynamic contact angle of ultra-hydrophobic surfaces using inclined surface and impinging droplet methods

    Science.gov (United States)

    Jasikova, Darina; Kotek, Michal

    2014-03-01

    The development of industrial technology also brings with optimized surface quality, particularly where there is contact with food. Application ultra-hydrophobic surface significantly reduces the growth of bacteria and facilitates cleaning processes. Testing and evaluation of surface quality are used two methods: impinging droplet and inclined surface method optimized with high speed shadowgraphy, which give information about dynamic contact angle. This article presents the results of research into new methods of measuring ultra-hydrophobic patented technology.

  16. Recovery of surface bacteria from and surface sanitization of cantaloupes.

    Science.gov (United States)

    Barak, Jeri D; Chue, Bryan; Mills, Daniel C

    2003-10-01

    Practical, effective methods that could be implemented in a food service establishment (restaurant or delicatessen) for the surface sanitization of cantaloupes were microbiologically evaluated. Cantaloupes (Cucumis melo L. var. reticulates) were immersed in an inoculum containing Salmonella enterica serovar Poona or Pantoea agglomerans at ca. 10(4) to 10(5) CFU/ml. An efficient method for the recovery of bacteria from the cantaloupe surface was developed and validated. The method consisted of washing the entire melon with Butterfield's buffer containing 1% Tween 80 in a plastic bag placed inside a plastic pail affixed to an orbital shaker. Levels of S. enterica Poona recovered by washing the entire melon were significantly higher than those recovered by the more common laboratory method of blending the rind. P. agglomerans can be used as a non-pathogenic proxy for S. enterica Poona. A three-compartment surface sanitization method consisting of washing with an antimicrobial soap solution, scrubbing with a brush in tap water, and immersion in 150 ppm of sodium hypochlorite reduced the initial level of recoverable viable bacteria by 99.8%. When examined separately, scrubbing with a vegetable brush in tap water, washing with soap, and dipping in chlorine were found to reduce the bacterial load by 70, 80, and 90%, respectively.

  17. Bacterial growth on a superhydrophobic surface containing silver nanoparticles

    International Nuclear Information System (INIS)

    Heinonen, S; Nikkanen, J-P; Laakso, J; Levänen, E; Raulio, M; Priha, O

    2013-01-01

    The antibacterial effect of silver can be exploited in the food and beverage industry and medicinal applications to reduce biofouling of surfaces. Very small amount of silver ions are enough to destructively affect the metabolism of bacteria. Moreover, superhydrophobic properties could reduce bacterial adhesion to the surface. In this study we fabricated superhydrophobic surfaces that contained nanosized silver particles. The superhydrophobic surfaces were manufactured onto stainless steel as combination of ceramic nanotopography and hydrophobication by fluorosilane. Silver nanoparticles were precipitated onto the surface by a chemical method. The dissolution of silver from the surface was tested in an aqueous environment under pH values of 1, 3, 5, 7, 9, 11 and 13. The pH value was adjusted with nitric acid and ammonia. It was found that dissolution rate of silver increased as the pH of the solution altered from the pH of de-ionized water to lower and higher pH values but dissolution occurred also in de-ionized water. The antimicrobial potential of this coating was investigated using bacterial strains isolated from the brewery equipment surfaces. The results showed that the number of bacteria adhering onto steel surface was significantly reduced (88%) on the superhydrophobic silver containing coating

  18. Bacterial growth on a superhydrophobic surface containing silver nanoparticles

    Science.gov (United States)

    Heinonen, S.; Nikkanen, J.-P.; Laakso, J.; Raulio, M.; Priha, O.; Levänen, E.

    2013-12-01

    The antibacterial effect of silver can be exploited in the food and beverage industry and medicinal applications to reduce biofouling of surfaces. Very small amount of silver ions are enough to destructively affect the metabolism of bacteria. Moreover, superhydrophobic properties could reduce bacterial adhesion to the surface. In this study we fabricated superhydrophobic surfaces that contained nanosized silver particles. The superhydrophobic surfaces were manufactured onto stainless steel as combination of ceramic nanotopography and hydrophobication by fluorosilane. Silver nanoparticles were precipitated onto the surface by a chemical method. The dissolution of silver from the surface was tested in an aqueous environment under pH values of 1, 3, 5, 7, 9, 11 and 13. The pH value was adjusted with nitric acid and ammonia. It was found that dissolution rate of silver increased as the pH of the solution altered from the pH of de-ionized water to lower and higher pH values but dissolution occurred also in de-ionized water. The antimicrobial potential of this coating was investigated using bacterial strains isolated from the brewery equipment surfaces. The results showed that the number of bacteria adhering onto steel surface was significantly reduced (88%) on the superhydrophobic silver containing coating.

  19. The law of corresponding states and surface tension of metals

    International Nuclear Information System (INIS)

    Digilov, R.

    2001-01-01

    Full Text: Surface tension of liquid metals is one of fundamental and most important quantities in theory and practice of material processing and its temperature dependence leads to the well-known Marangoni convection. Although currently methods are sufficiently precise to measure the surface tension, there are uncertainties in experimental data and its temperature dependence mainly due to impurity, which even a trace of it strongly affects the results of measurements. The theoretical treatment from the first principles is unwieldy and not always permits one to calculate the surface tension with certainty. Another active research field deals with empirical correlation between the surface tension and bulk thermodynamic properties, which we interpret as a simple consequence of the law of corresponding states. In order to relate the surface tension and to bulk properties of liquid metals the reduced formula is derived by scaling with the melting point T m (0) at p = 0 and atomic volume Ω 0 2/3 at T = 0 K as macroscopic parameters for scaling ε and a characterizing the interatomic potential in metals. The reduced surface tension and the reduced surface entropy obtained in high temperature limit are discussed and compared with the experiment. The reduced temperature coefficient of the surface tension found is a universal constant for the metals of the same structure. It is shown that pressure dependence of the surface tension, so called baric coefficient of the surface tension, can be described by pressure dependence of scaling parameters T m (p) and Ω 0 (p). (author)

  20. Modelling of surface evolution of rough surface on divertor target in fusion devices

    International Nuclear Information System (INIS)

    Dai, Shuyu; Liu, Shengguang; Sun, Jizhong; Kirschner, A.; Kawamura, G.; Tskhakaya, D.; Ding, Rui; Luo, Guangnan; Wang, Dezhen

    2015-01-01

    Highlights: • We study the surface evolution of rough surface on divertor target in fusion devices. • The effects of gyration motion and E × B drift affect 3D angular distribution. • A larger magnetic field angle leads to a reduced net eroded areal density. • The rough surface evolution affects the physical sputtering yield. - Abstract: The 3D Monte-Carlo code SURO has been used to study the surface evolution of rough surface on the divertor target in fusion devices. The edge plasma at divertor region is modelled by the SDPIC code and used as input data for SURO. Coupled with SDPIC, SURO can perform more sophisticated simulations to calculate the local angle and surface evolution of rough surface. The simulation results show that the incident direction of magnetic field, gyration and E × B force has a significant impact on 3D angular distribution of background plasma and accordingly on the erosion of rough surface. The net eroded areal density of rough surface is studied by varying the magnetic field angle with surface normal. The evolution of the microscopic morphology of rough surface can lead to a significant change in the physical sputtering yield

  1. Using dual response surfaces to reduce variability in launch vehicle design: A case study

    International Nuclear Information System (INIS)

    Yeniay, Ozgur; Unal, Resit; Lepsch, Roger A.

    2006-01-01

    Space transportation system conceptual design is a multidisciplinary process containing considerable element of risk. Uncertainties from one engineering discipline may propagate to another through linking parameters and the final system output may have an accumulation of risk. This may lead to significant deviations from expected performance. An estimate of variability or design risk therefore becomes essential for a robust design. This study utilizes the dual response surface approach to quantify variability in critical performance characteristics during conceptual design phase of a launch vehicle. Using design of experiments methods and disciplinary design analysis codes, dual response surfaces are constructed for the mean and standard deviation to quantify variability in vehicle weight and sizing analysis. Next, an optimum solution is sought to minimize variability subject to a constraint on mean weight. In this application, the dual response surface approach lead to quantifying and minimizing variability without much increase in design effort

  2. Surface Analysis of Marine Sulphate-Reducing Bacteria Exo polymers on Steel During Bio corrosion Using X-ray Photoelectron Spectroscopy

    International Nuclear Information System (INIS)

    Fathul Karim Sahrani; Madzlan Abd. Aziz; Zaharah Ibrahim; Adibah Yahya

    2008-01-01

    The aim of this study was to determine the surface chemistry during bio corrosion process on growth and on the production of exo polymeric substances (EPS) in batch cultures of mix-strains of marine sulphate-reducing bacteria (SRB) isolated from Malaysian Shipyard and Engineering Harbours, Pasir Gudang. The EPS and precipitates were analyzed by x-ray photoelectron spectroscopy (XPS). The XPS results indicate that Fe(2p 3/2 ) spectrum for iron sulphide can be fitted with Fe(II) and Fe(III) components, both corresponding to Fe-S bond types. The absence of oxide oxygen in the O(1s) spectrum and Fe(III)-O bond types in the Fe(2p 3/2 ) spectrum supports the conclusion that iron sulphides are composed of both ferric and ferrous iron coordinated with mono sulphide and disulphide. (author)

  3. HybridPLAY: A New Technology to Foster Outdoors Physical Activity, Verbal Communication and Teamwork

    Directory of Open Access Journals (Sweden)

    Diego José Díaz

    2016-04-01

    Full Text Available This paper presents HybridPLAY, a novel technology composed of a sensor and mobile-based video games that transforms urban playgrounds into game scenarios. With this technology we aim to stimulate physical activity and playful learning by creating an entertaining environment in which users can actively participate and collaborate. HybridPLAY is different from other existing technologies that enhance playgrounds, as it is not integrated in them but can be attached to the different elements of the playgrounds, making its use more ubiquitous (i.e., not restricted to the playgrounds. HybridPLAY was born in 2007 as an artistic concept, and evolved after different phases of research and testing by almost 2000 users around the world (in workshops, artistic events, conferences, etc.. Here, we present the temporal evolution of HybridPLAY with the different versions of the sensors and the video games, and a detailed technical description of the sensors and the way interactions are produced. We also present the outcomes after the evaluation by users at different events and workshops. We believe that HybridPLAY has great potential to contribute to increased physical activity in kids, and also to improve the learning process and monitoring at school centres by letting users create the content of the apps, leading to new narratives and fostering creativity.

  4. HybridPLAY: A New Technology to Foster Outdoors Physical Activity, Verbal Communication and Teamwork

    Science.gov (United States)

    Díaz, Diego José; Boj, Clara; Portalés, Cristina

    2016-01-01

    This paper presents HybridPLAY, a novel technology composed of a sensor and mobile-based video games that transforms urban playgrounds into game scenarios. With this technology we aim to stimulate physical activity and playful learning by creating an entertaining environment in which users can actively participate and collaborate. HybridPLAY is different from other existing technologies that enhance playgrounds, as it is not integrated in them but can be attached to the different elements of the playgrounds, making its use more ubiquitous (i.e., not restricted to the playgrounds). HybridPLAY was born in 2007 as an artistic concept, and evolved after different phases of research and testing by almost 2000 users around the world (in workshops, artistic events, conferences, etc.). Here, we present the temporal evolution of HybridPLAY with the different versions of the sensors and the video games, and a detailed technical description of the sensors and the way interactions are produced. We also present the outcomes after the evaluation by users at different events and workshops. We believe that HybridPLAY has great potential to contribute to increased physical activity in kids, and also to improve the learning process and monitoring at school centres by letting users create the content of the apps, leading to new narratives and fostering creativity. PMID:27120601

  5. Polymer-Based Surfaces Designed to Reduce Biofilm Formation: From Antimicrobial Polymers to Strategies for Long-Term Applications.

    Science.gov (United States)

    Riga, Esther K; Vöhringer, Maria; Widyaya, Vania Tanda; Lienkamp, Karen

    2017-10-01

    Contact-active antimicrobial polymer surfaces bear cationic charges and kill or deactivate bacteria by interaction with the negatively charged parts of their cell envelope (lipopolysaccharides, peptidoglycan, and membrane lipids). The exact mechanism of this interaction is still under debate. While cationic antimicrobial polymer surfaces can be very useful for short-term applications, they lose their activity once they are contaminated by a sufficiently thick layer of adhering biomolecules or bacterial cell debris. This layer shields incoming bacteria from the antimicrobially active cationic surface moieties. Besides discussing antimicrobial surfaces, this feature article focuses on recent strategies that were developed to overcome the contamination problem. This includes bifunctional materials with simultaneously presented antimicrobial and protein-repellent moieties; polymer surfaces that can be switched from an antimicrobial, cell-attractive to a cell-repellent state; polymer surfaces that can be regenerated by enzyme action; degradable antimicrobial polymers; and antimicrobial polymer surfaces with removable top layers. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. Surface Photochemistry of Adsorbed Nitrate: The Role of Adsorbed Water in the Formation of Reduced Nitrogen Species on α-Fe2O3 Particle Surfaces

    NARCIS (Netherlands)

    Nanayakkara, C.E.; Jayaweera, P.M.; Rubasinghege, G; Baltrusaitis, Jonas; Grassian, V.H.

    2014-01-01

    The surface photochemistry of nitrate, formed from nitric acid adsorption, on hematite (α-Fe2O3) particle surfaces under different environmental conditions is investigated using X-ray photoelectron spectroscopy (XPS). Following exposure of α-Fe2O3 particle surfaces to gas-phase nitric acid, a peak

  7. Low surface damage dry etched black silicon

    Science.gov (United States)

    Plakhotnyuk, Maksym M.; Gaudig, Maria; Davidsen, Rasmus Schmidt; Lindhard, Jonas Michael; Hirsch, Jens; Lausch, Dominik; Schmidt, Michael Stenbæk; Stamate, Eugen; Hansen, Ole

    2017-10-01

    Black silicon (bSi) is promising for integration into silicon solar cell fabrication flow due to its excellent light trapping and low reflectance, and a continuously improving passivation. However, intensive ion bombardment during the reactive ion etching used to fabricate bSi induces surface damage that causes significant recombination. Here, we present a process optimization strategy for bSi, where surface damage is reduced and surface passivation is improved while excellent light trapping and low reflectance are maintained. We demonstrate that reduction of the capacitively coupled plasma power, during reactive ion etching at non-cryogenic temperature (-20 °C), preserves the reflectivity below 1% and improves the effective minority carrier lifetime due to reduced ion energy. We investigate the effect of the etching process on the surface morphology, light trapping, reflectance, transmittance, and effective lifetime of bSi. Additional surface passivation using atomic layer deposition of Al2O3 significantly improves the effective lifetime. For n-type wafers, the lifetime reaches 12 ms for polished and 7.5 ms for bSi surfaces. For p-type wafers, the lifetime reaches 800 μs for both polished and bSi surfaces.

  8. Fabrication of zero contact angle ultra-super hydrophilic surfaces.

    Science.gov (United States)

    Jothi Prakash, C G; Clement Raj, C; Prasanth, R

    2017-06-15

    Zero contact angle surfaces have been created with the combined effect of nanostructure and UV illumination. The contact angle of titanium surface has been optimized to 3.25°±1°. with nanotubular structures through electrochemical surface modification. The porosity and surface energy of tubular TiO 2 layer play critical role over the surface wettability and the hydrophilicity of the surface. The surface free energy has been enhanced from 23.72mJ/m 2 (bare titanium surface) to 87.11mJ/m 2 (nanotubular surface). Similar surface with TiO 2 nanoparticles coating shows superhydrophilicity with contact angle up to 5.63°±0.95°. This implies liquid imbibition and surface curvature play a crucial role in surface hydrophilicity. The contact angle has been further reduced to 0°±0.86° by illuminating the surface with UV radiation. Results shows that by tuning the nanotube morphology, highly porous surfaces can be fabricated to reduce contact angle and enhance wettability. This study provides an insight into the inter-relationship between surface structural factors and ultra-superhydrophilic surfaces which can help to optimize thermal hydraulic and self cleaning surfaces. Copyright © 2017. Published by Elsevier Inc.

  9. Using squeeze-film effect to reduce surface friction in electrostatic actuators

    DEFF Research Database (Denmark)

    Zsurzsan, Tiberiu-Gabriel; Yamamoto, Akio; Zhang, Zhe

    2015-01-01

    This paper presents a method of reducing load friction in two degrees-of-freedom (2-DOF) transparent electrostatic induction actuator by using vibration-induced squeeze film effect. An experimental set-up was built to prove the concept. An overall 70% reduction in required driving voltage...

  10. Reduced chemical warfare agent sorption in polyurethane-painted surfaces via plasma-enhanced chemical vapor deposition of perfluoroalkanes.

    Science.gov (United States)

    Gordon, Wesley O; Peterson, Gregory W; Durke, Erin M

    2015-04-01

    Perfluoralkalation via plasma chemical vapor deposition has been used to improve hydrophobicity of surfaces. We have investigated this technique to improve the resistance of commercial polyurethane coatings to chemicals, such as chemical warfare agents. The reported results indicate the surface treatment minimizes the spread of agent droplets and the sorption of agent into the coating. The improvement in resistance is likely due to reduction of the coating's surface free energy via fluorine incorporation, but may also have contributing effects from surface morphology changes. The data indicates that plasma-based surface modifications may have utility in improving chemical resistance of commercial coatings.

  11. Laser Surface Treatment of Sintered Alumina

    Science.gov (United States)

    Hagemann, R.; Noelke, C.; Kaierle, S.; Wesling, V.

    Sintered alumina ceramics are used as refractory materials for industrial aluminum furnaces. In this environment the ceramic surface is in permanent contact with molten aluminum resulting in deposition of oxidic material on its surface. Consequently, a lower volume capacity as well as thermal efficiency of the furnaces follows. To reduce oxidic adherence of the ceramic material, two laser-based surface treatment processes were investigated: a powder- based single-step laser cladding and a laser surface remelting. Main objective is to achieve an improved surface quality of the ceramic material considering the industrial requirements as a high process speed.

  12. Molecular printboards: monolayers of beta-cyclodextrins on silicon oxide surfaces

    NARCIS (Netherlands)

    Onclin, S.; Mulder, A.; Huskens, Jurriaan; Ravoo, B.J.; Reinhoudt, David

    2004-01-01

    Monolayers of β-cyclodextrin host molecules have been prepared on SiO2 surfaces. An ordered and stable cyano-terminated monolayer was modified in three consecutive surface reactions. First, the cyanide groups were reduced to their corresponding free amines using Red Al as a reducing agent. Second,

  13. Liquid infused porous surfaces for mineral fouling mitigation.

    Science.gov (United States)

    Charpentier, Thibaut V J; Neville, Anne; Baudin, Sophie; Smith, Margaret J; Euvrard, Myriam; Bell, Ashley; Wang, Chun; Barker, Richard

    2015-04-15

    Prevention of mineral fouling, known as scale, is a long-standing problem in a wide variety of industrial applications, such as oil production, water treatment, and many others. The build-up of inorganic scale such as calcium carbonate on surfaces and facilities is undesirable as it can result in safety risks and associated flow assurance issues. To date the overwhelming amount of research has mainly focused on chemical inhibition of scale bulk precipitation and little attention has been paid to deposition onto surfaces. The development of novel more environmentally-friendly strategies to control mineral fouling will most probably necessitate a multifunctional approach including surface engineering. In this study, we demonstrate that liquid infused porous surfaces provide an appealing strategy for surface modification to reduce mineral scale deposition. Microporous polypyrrole (PPy) coatings were fabricated onto stainless steel substrates by electrodeposition in potentiostatic mode. Subsequent infusion of low surface energy lubricants (fluorinated oil Fluorinert FC-70 and ionic liquid 1-Butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (BMIm)) into the porous coatings results in liquid-repellent slippery surfaces. To assess their ability to reduce surface scaling the coatings were subjected to a calcium carbonate scaling environment and the scale on the surface was quantified using Inductively Coupled Plasma Atomic Emission Spectroscopy (ICP-AES). PPy surfaces infused with BMIm (and Fluorinert to a lesser extent) exhibit remarkable antifouling properties with the calcium carbonate deposition reduced by 18 times in comparison to untreated stainless steel. These scaling tests suggest a correlation between the stability of the liquid infused surfaces in artificial brines and fouling reduction efficiency. The current work shows the great potential of such novel coatings for the management of mineral scale fouling. Copyright © 2014 Elsevier Inc. All rights

  14. Electrically driven surface plasmon light-emitting diodes

    DEFF Research Database (Denmark)

    Fadil, Ahmed; Ou, Yiyu; Iida, Daisuke

    We investigate device performance of GaN light-emitting diodes (LEDs) with a 30-nm p-GaN layer. The metallization used to separate the p-contact from plasmonic metals, reveals limitations on current spreading which reduces surface plasmonic enhancement.......We investigate device performance of GaN light-emitting diodes (LEDs) with a 30-nm p-GaN layer. The metallization used to separate the p-contact from plasmonic metals, reveals limitations on current spreading which reduces surface plasmonic enhancement....

  15. Surface-Activated Coupling Reactions Confined on a Surface.

    Science.gov (United States)

    Dong, Lei; Liu, Pei Nian; Lin, Nian

    2015-10-20

    -functional theory (DFT) transition-state calculations have been used to shed light on reaction mechanisms and to unravel the trends of different surface materials. In this Account, we discuss recent progress made in two widely studied surface-confined coupling reactions, aryl-aryl (Ullmann-type) coupling and alkyne-alkyne (Glaser-type) coupling, and focus on surface activation effects. Combined experimental and theoretical studies on the same reactions taking place on different metal surfaces have clearly demonstrated that different surfaces not only reduce the reaction barrier differently and render different reaction pathways but also control the morphology of the reaction products and, to some degree, select the reaction products. We end the Account with a list of questions to be addressed in the future. Satisfactorily answering these questions may lead to using the surface-confined coupling reactions to synthesize predefined products with high yield.

  16. System and method for reducing combustion dynamics and NO.sub.x in a combustor

    Science.gov (United States)

    Uhm, Jong H.; Johnson, Thomas Edward

    2015-11-20

    A system for reducing combustion dynamics and NO.sub.x in a combustor includes a tube bundle that extends radially across at least a portion of the combustor, wherein the tube bundle comprises an upstream surface axially separated from a downstream surface. A shroud circumferentially surrounds the upstream and downstream surfaces. A plurality of tubes extends through the tube bundle from the upstream surface through the downstream surface, wherein the downstream surface is stepped to produce tubes having different lengths through the tube bundle. A method for reducing combustion dynamics and NO.sub.x in a combustor includes flowing a working fluid through a plurality of tubes radially arranged between an upstream surface and a downstream surface of an end cap that extends radially across at least a portion of the combustor, wherein the downstream surface is stepped.

  17. Static elliptic minimal surfaces in AdS{sub 4}

    Energy Technology Data Exchange (ETDEWEB)

    Pastras, Georgios [NCSR ' ' Demokritos' ' , Institute of Nuclear and Particle Physics, Attiki (Greece)

    2017-11-15

    The Ryu-Takayanagi conjecture connects the entanglement entropy in the boundary CFT to the area of open co-dimension two minimal surfaces in the bulk. Especially in AdS{sub 4}, the latter are two-dimensional surfaces, and, thus, solutions of a Euclidean non-linear sigma model on a symmetric target space that can be reduced to an integrable system via Pohlmeyer reduction. In this work, we construct static minimal surfaces in AdS{sub 4} that correspond to elliptic solutions of the reduced system, namely the cosh-Gordon equation, via the inversion of Pohlmeyer reduction. The constructed minimal surfaces comprise a two-parameter family of surfaces that include helicoids and catenoids in H{sup 3} as special limits. Minimal surfaces that correspond to identical boundary conditions are discovered within the constructed family of surfaces and the relevant geometric phase transitions are studied. (orig.)

  18. Laser surface modification of medical grade alloys for reduced heating in a magnetic resonance imaging environment

    Energy Technology Data Exchange (ETDEWEB)

    Benafan, O., E-mail: othmane.benafan@nasa.gov, E-mail: raj@ucf.edu; Vaidyanathan, R., E-mail: othmane.benafan@nasa.gov, E-mail: raj@ucf.edu [Advanced Materials Processing and Analysis Center (AMPAC), Materials Science and Engineering, Mechanical and Aerospace Engineering, University of Central Florida, Orlando, Florida 32816 (United States); Chen, S.-Y.; Kar, A. [Laser-Advanced Materials Processing Laboratory, Center for Research and Education in Optics and Lasers (CREOL), College of Optics and Photonics, University of Central Florida, Orlando, Florida 32816 (United States)

    2015-12-15

    Nanoscale surface modification of medical grade metallic alloys was conducted using a neodymium-doped yttrium aluminum garnet laser-based dopant diffusion technique. The objective of this approach was to minimize the induction heating by reducing the absorbed radio frequency field. Such an approach is advantageous in that the dopant is diffused into the alloy and is not susceptible to detachment or spallation as would an externally applied coating, and is expected to not deteriorate the mechanical and electrical properties of the base alloy or device. Experiments were conducted using a controlled environment laser system with the ability to control laser properties (i.e., laser power, spot size, and irradiation time) and dopant characteristics (i.e., temperature, concentration, and pressure). The reflective and transmissive properties of both the doped and untreated samples were measured in a radio frequency (63.86 MHz) magnetic field using a system comprising a high power signal generator, a localized magnetic field source and sensor, and a signal analyzer. The results indicate an increase in the reflectivity of the laser-treated samples compared to untreated samples. The effect of reflectivity on the heating of the alloys is investigated through a mathematical model incorporating Maxwell’s equations and heat conduction.

  19. Reducing surface water pollution through the assessment of the cost-effectiveness of BMPs at different spatial scales.

    Science.gov (United States)

    Panagopoulos, Y; Makropoulos, C; Mimikou, M

    2011-10-01

    Two kinds of agricultural Best Management Practices (BMPs) were examined with respect to cost-effectiveness (CE) in reducing sediment, nitrates-nitrogen (NO(3)-N) and total phosphorus (TP) losses to surface waters of the Arachtos catchment in Western Greece. The establishment of filter strips at the edge of fields and a non-structural measure, namely fertilization reduction in alfalfa, combined with contour farming and zero-tillage in corn and reduction of animal numbers in pastureland, were evaluated. The Soil and Water Assessment Tool (SWAT) model was used as the non-point-source (NPS) estimator, while a simple economic component was developed estimating BMP implementation cost as the mean annual expenses needed to undertake and operate the practice for a 5-year period. After each BMP implementation, the ratio of their CE in reducing pollution was calculated for each Hydrologic Response Unit (HRU) separately, for each agricultural land use type entirely and for the whole catchment. The results at the HRU scale are presented comprehensively on a map, demonstrating the spatial differentiation of CE ratios across the catchment that enhances the identification of locations where each BMP is most advisable for implementation. Based on the analysis, a catchment management solution of affordable total cost would include the expensive measure of filter strips in corn and only in a small number of pastureland fields, in combination with the profitable measure of reducing fertilization to alfalfa fields. When examined for its impact on river loads at the outlet, the latter measure led to a 20 tn or 8% annual decrease of TP from the baseline with savings of 15€/kg of pollutant reduction. Filter strips in corn fields reduced annual sediments by 66 Ktn or 5%, NO(3)-N by 71 tn or 9.5% and TP by 27 tn or 10%, with an additional cost of 3.1 €/tn, 3.3 €/kg and 8.1 €/kg of each pollutant respectively. The study concludes that considerable reductions of several

  20. Support surfaces for pressure ulcer prevention: A network meta-analysis

    Science.gov (United States)

    Dumville, Jo C.; Cullum, Nicky

    2018-01-01

    Background Pressure ulcers are a prevalent and global issue and support surfaces are widely used for preventing ulceration. However, the diversity of available support surfaces and the lack of direct comparisons in RCTs make decision-making difficult. Objectives To determine, using network meta-analysis, the relative effects of different support surfaces in reducing pressure ulcer incidence and comfort and to rank these support surfaces in order of their effectiveness. Methods We conducted a systematic review, using a literature search up to November 2016, to identify randomised trials comparing support surfaces for pressure ulcer prevention. Two reviewers independently performed study selection, risk of bias assessment and data extraction. We grouped the support surfaces according to their characteristics and formed evidence networks using these groups. We used network meta-analysis to estimate the relative effects and effectiveness ranking of the groups for the outcomes of pressure ulcer incidence and participant comfort. GRADE was used to assess the certainty of evidence. Main results We included 65 studies in the review. The network for assessing pressure ulcer incidence comprised evidence of low or very low certainty for most network contrasts. There was moderate-certainty evidence that powered active air surfaces and powered hybrid air surfaces probably reduce pressure ulcer incidence compared with standard hospital surfaces (risk ratios (RR) 0.42, 95% confidence intervals (CI) 0.29 to 0.63; 0.22, 0.07 to 0.66, respectively). The network for comfort suggested that powered active air-surfaces are probably slightly less comfortable than standard hospital mattresses (RR 0.80, 95% CI 0.69 to 0.94; moderate-certainty evidence). Conclusions This is the first network meta-analysis of the effects of support surfaces for pressure ulcer prevention. Powered active air-surfaces probably reduce pressure ulcer incidence, but are probably less comfortable than standard

  1. Support surfaces for pressure ulcer prevention: A network meta-analysis.

    Science.gov (United States)

    Shi, Chunhu; Dumville, Jo C; Cullum, Nicky

    2018-01-01

    Pressure ulcers are a prevalent and global issue and support surfaces are widely used for preventing ulceration. However, the diversity of available support surfaces and the lack of direct comparisons in RCTs make decision-making difficult. To determine, using network meta-analysis, the relative effects of different support surfaces in reducing pressure ulcer incidence and comfort and to rank these support surfaces in order of their effectiveness. We conducted a systematic review, using a literature search up to November 2016, to identify randomised trials comparing support surfaces for pressure ulcer prevention. Two reviewers independently performed study selection, risk of bias assessment and data extraction. We grouped the support surfaces according to their characteristics and formed evidence networks using these groups. We used network meta-analysis to estimate the relative effects and effectiveness ranking of the groups for the outcomes of pressure ulcer incidence and participant comfort. GRADE was used to assess the certainty of evidence. We included 65 studies in the review. The network for assessing pressure ulcer incidence comprised evidence of low or very low certainty for most network contrasts. There was moderate-certainty evidence that powered active air surfaces and powered hybrid air surfaces probably reduce pressure ulcer incidence compared with standard hospital surfaces (risk ratios (RR) 0.42, 95% confidence intervals (CI) 0.29 to 0.63; 0.22, 0.07 to 0.66, respectively). The network for comfort suggested that powered active air-surfaces are probably slightly less comfortable than standard hospital mattresses (RR 0.80, 95% CI 0.69 to 0.94; moderate-certainty evidence). This is the first network meta-analysis of the effects of support surfaces for pressure ulcer prevention. Powered active air-surfaces probably reduce pressure ulcer incidence, but are probably less comfortable than standard hospital surfaces. Most prevention evidence was of low or

  2. Support surfaces for pressure ulcer prevention: A network meta-analysis.

    Directory of Open Access Journals (Sweden)

    Chunhu Shi

    Full Text Available Pressure ulcers are a prevalent and global issue and support surfaces are widely used for preventing ulceration. However, the diversity of available support surfaces and the lack of direct comparisons in RCTs make decision-making difficult.To determine, using network meta-analysis, the relative effects of different support surfaces in reducing pressure ulcer incidence and comfort and to rank these support surfaces in order of their effectiveness.We conducted a systematic review, using a literature search up to November 2016, to identify randomised trials comparing support surfaces for pressure ulcer prevention. Two reviewers independently performed study selection, risk of bias assessment and data extraction. We grouped the support surfaces according to their characteristics and formed evidence networks using these groups. We used network meta-analysis to estimate the relative effects and effectiveness ranking of the groups for the outcomes of pressure ulcer incidence and participant comfort. GRADE was used to assess the certainty of evidence.We included 65 studies in the review. The network for assessing pressure ulcer incidence comprised evidence of low or very low certainty for most network contrasts. There was moderate-certainty evidence that powered active air surfaces and powered hybrid air surfaces probably reduce pressure ulcer incidence compared with standard hospital surfaces (risk ratios (RR 0.42, 95% confidence intervals (CI 0.29 to 0.63; 0.22, 0.07 to 0.66, respectively. The network for comfort suggested that powered active air-surfaces are probably slightly less comfortable than standard hospital mattresses (RR 0.80, 95% CI 0.69 to 0.94; moderate-certainty evidence.This is the first network meta-analysis of the effects of support surfaces for pressure ulcer prevention. Powered active air-surfaces probably reduce pressure ulcer incidence, but are probably less comfortable than standard hospital surfaces. Most prevention evidence was

  3. A novel thromboxane A2 receptor N42S variant results in reduced surface expression and platelet dysfunction.

    Science.gov (United States)

    Nisar, Shaista P; Lordkipanidzé, Marie; Jones, Matthew L; Dawood, Ban; Murden, Sherina; Cunningham, Margaret R; Mumford, Andrew D; Wilde, Jonathan T; Watson, Steve P; Mundell, Stuart J; Lowe, Gillian C

    2014-05-05

    A small number of thromboxane receptor variants have been described in patients with a bleeding history that result in platelet dysfunction. We have identified a patient with a history of significant bleeding, who expresses a novel heterozygous thromboxane receptor variant that predicts an asparagine to serine substitution (N42S). This asparagine is conserved across all class A GPCRs, suggesting a vital role for receptor structure and function.We investigated the functional consequences of the TP receptor heterozygous N42S substitution by performing platelet function studies on platelet-rich plasma taken from the patient and healthy controls. We investigated the N42S mutation by expressing the wild-type (WT) and mutant receptor in human embryonic kidney (HEK) cells. Aggregation studies showed an ablation of arachidonic acid responses in the patient, whilst there was right-ward shift of the U46619 concentration response curve (CRC). Thromboxane generation was unaffected. Calcium mobilisation studies in cells lines showed a rightward shift of the U46619 CRC in N42S-expressing cells compared to WT. Radioligand binding studies revealed a reduction in BMax in platelets taken from the patient and in N42S-expressing cells, whilst cell studies confirmed poor surface expression. We have identified a novel thromboxane receptor variant, N42S, which results in platelet dysfunction due to reduced surface expression. It is associated with a significant bleeding history in the patient in whom it was identified. This is the first description of a naturally occurring variant that results in the substitution of this highly conserved residue and confirms the importance of this residue for correct GPCR function.

  4. REDUCING THE INTENSITY OF TAKEAWAY PULVERIZED COAL BY USING SPECIAL SOLUTION

    Directory of Open Access Journals (Sweden)

    M. M. Biliaiev

    2017-04-01

    Full Text Available Purpose. The article is aimed: 1 to develop the coal coating solution in open railway cars or to cover coal piles to minimize the coal dust losses; 2 creating a mathematical model of the process of the solution feeding to the surface of coal. Methodology. To solve this problem, it was developed a special solution containing cheap industrial wastes and semiproducts of chemical industries. It was conducted a physical experiment to assess the intensity of coal dust loss when using the developed solution. A mathematical model based on the use of the motion equations of the ideal fluid and mass transfer was developed. The developed numerical models are the basis of the application program package created for assessing the quality of processing the coal surface by special solution. Findings. The results of the conducted physical experiment to assess the magnitude of the coal dust loss on the model of the coal pile in the processing of its surface with a special solution and without processing are presented in the article. It is shown that the application of the proposed solution for surface processing of coal can significantly reduce the coal dust loss. This makes it possible to reduce the amount of economic losses and reduce the level of air dust pollution in work areas. The results of computational experiments carried out on the basis of the constructed numerical models are presented in the article. Originality. Authors proposed a new solution for the coal surface processing in order to minimize the removal of pulverized coal from the coal pile, which substantially reduces the coal losses. There were created numerical models to take into account the relevant factors influencing the solution dispersion process in the atmosphere from coal processing in gondola cars. Practical value. Solution, proposed in the article has a low price, because it can be created on the basis of industrial production wastes. Application of this solution can significantly

  5. Reduction of surface erosion in fusion reactors

    International Nuclear Information System (INIS)

    Rossing, T.D.; Das, S.K.; Kaminsky, M.

    1976-01-01

    Some of the major processes leading to surface erosion in fusion reactors are reviewed briefly, including blistering by implanted gas, sputtering by ions, atoms, and neutrons, and vaporization by local heating. Surface erosion affects the structural integrity and limits the lifetime of reactor components exposed to plasma radiation. In addition, some of the processes leading to surface erosion also cause the release of plasma contaminants. Methods proposed to reduce surface erosion have included control of surface temperature, selection of materials with a favorable microstructure, chemical and mechanical treatment of surfaces, and employment of protective surface coatings, wall liners, and divertors. The advantages and disadvantages of some of these methods are discussed

  6. Natural Contamination and Surface Flashover on Silicone Rubber Surface under Haze–Fog Environment

    Directory of Open Access Journals (Sweden)

    Ang Ren

    2017-10-01

    Full Text Available Anti-pollution flashover of insulator is important for power systems. In recent years, haze-fog weather occurs frequently, which makes discharge occurs easily on the insulator surface and accelerates insulation aging of insulator. In order to study the influence of haze-fog on the surface discharge of room temperature vulcanized silicone rubber, an artificial haze-fog lab was established. Based on four consecutive years of insulator contamination accumulation and atmospheric sampling in haze-fog environment, the contamination configuration appropriate for RTV-coated surface discharge test under simulation environment of haze-fog was put forward. ANSYS Maxwell was used to analyze the influence of room temperature vulcanized silicone rubber surface attachments on electric field distribution. The changes of droplet on the polluted room temperature vulcanized silicone rubber surface and the corresponding surface flashover voltage under alternating current (AC, direct current (DC positive polar (+, and DC negative polar (− power source were recorded by a high speed camera. The results are as follows: The main ion components from haze-fog atmospheric particles are NO3−, SO42−, NH4+, and Ca2+. In haze-fog environment, both the equivalent salt deposit density (ESDD and non-soluble deposit density (NSDD of insulators are higher than that under general environment. The amount of large particles on the AC transmission line is greater than that of the DC transmission line. The influence of DC polarity power source on the distribution of contamination particle size is not significant. After the deposition of haze-fog, the local conductivity of the room temperature vulcanized silicone rubber surface increased, which caused the flashover voltage reduce. Discharge is liable to occur at the triple junction point of droplet, air, and room temperature vulcanized silicone rubber surface. After the deformation or movement of droplets, a new triple junction

  7. Defining the Post-Machined Sub-surface in Austenitic Stainless Steels

    Science.gov (United States)

    Srinivasan, N.; Sunil Kumar, B.; Kain, V.; Birbilis, N.; Joshi, S. S.; Sivaprasad, P. V.; Chai, G.; Durgaprasad, A.; Bhattacharya, S.; Samajdar, I.

    2018-06-01

    Austenitic stainless steels grades, with differences in chemistry, stacking fault energy, and thermal conductivity, were subjected to vertical milling. Anodic potentiodynamic polarization was able to differentiate (with machining speed/strain rate) between different post-machined sub-surfaces in SS 316L and Alloy A (a Cu containing austenitic stainless steel: Sanicroe 28™), but not in SS 304L. However, such differences (in the post-machined sub-surfaces) were revealed in surface roughness, sub-surface residual stresses and misorientations, and in the relative presence of sub-surface Cr2O3 films. It was shown, quantitatively, that higher machining speed reduced surface roughness and also reduced the effective depths of the affected sub-surface layers. A qualitative explanation on the sub-surface microstructural developments was provided based on the temperature-dependent thermal conductivity values. The results herein represent a mechanistic understanding to rationalize the corrosion performance of widely adopted engineering alloys.

  8. Defining the Post-Machined Sub-surface in Austenitic Stainless Steels

    Science.gov (United States)

    Srinivasan, N.; Sunil Kumar, B.; Kain, V.; Birbilis, N.; Joshi, S. S.; Sivaprasad, P. V.; Chai, G.; Durgaprasad, A.; Bhattacharya, S.; Samajdar, I.

    2018-04-01

    Austenitic stainless steels grades, with differences in chemistry, stacking fault energy, and thermal conductivity, were subjected to vertical milling. Anodic potentiodynamic polarization was able to differentiate (with machining speed/strain rate) between different post-machined sub-surfaces in SS 316L and Alloy A (a Cu containing austenitic stainless steel: Sanicroe 28™), but not in SS 304L. However, such differences (in the post-machined sub-surfaces) were revealed in surface roughness, sub-surface residual stresses and misorientations, and in the relative presence of sub-surface Cr2O3 films. It was shown, quantitatively, that higher machining speed reduced surface roughness and also reduced the effective depths of the affected sub-surface layers. A qualitative explanation on the sub-surface microstructural developments was provided based on the temperature-dependent thermal conductivity values. The results herein represent a mechanistic understanding to rationalize the corrosion performance of widely adopted engineering alloys.

  9. Osteopontin adsorption to Gram-positive cells reduces adhesion forces and attachment to surfaces under flow

    DEFF Research Database (Denmark)

    Kristensen, M F; Zeng, G; Neu, T R

    2017-01-01

    caries or medical device-related infections. It further investigated if OPN's effect on adhesion is caused by blocking the accessibility of glycoconjugates on bacterial surfaces. Bacterial adhesion was determined in a shear-controlled flow cell system in the presence of different concentrations of OPN......The bovine milk protein osteopontin (OPN) may be an efficient means to prevent bacterial adhesion to dental tissues and control biofilm formation. This study sought to determine to what extent OPN impacts adhesion forces and surface attachment of different bacterial strains involved in dental......, and interaction forces of single bacteria were quantified using single-cell force spectroscopy before and after OPN exposure. Moreover, the study investigated OPN's effect on the accessibility of cell surface glycoconjugates through fluorescence lectin-binding analysis. OPN strongly affected bacterial adhesion...

  10. Insights into the Surface Reactivity of Cermet and Perovskite Electrodes in Oxidizing, Reducing, and Humid Environments.

    Science.gov (United States)

    Paloukis, Fotios; Papazisi, Kalliopi M; Dintzer, Thierry; Papaefthimiou, Vasiliki; Saveleva, Viktoriia A; Balomenou, Stella P; Tsiplakides, Dimitrios; Bournel, Fabrice; Gallet, Jean-Jacques; Zafeiratos, Spyridon

    2017-08-02

    Understanding the surface chemistry of electrode materials under gas environments is important in order to control their performance during electrochemical and catalytic applications. This work compares the surface reactivity of Ni/YSZ and La 0.75 Sr 0.25 Cr 0.9 Fe 0.1 O 3 , which are commonly used types of electrodes in solid oxide electrochemical devices. In situ synchrotron-based near-ambient pressure photoemission and absorption spectroscopy experiments, assisted by theoretical spectral simulations and combined with microscopy and electrochemical measurements, are used to monitor the effect of the gas atmosphere on the chemical state, the morphology, and the electrical conductivity of the electrodes. It is shown that the surface of both electrode types readjusts fast to the reactive gas atmosphere and their surface composition is notably modified. In the case of Ni/YSZ, this is followed by evident changes in the oxidation state of nickel, while for La 0.75 Sr 0.25 Cr 0.9 Fe 0.1 O 3 , a fine adjustment of the Cr valence and strong Sr segregation is observed. An important difference between the two electrodes is their capacity to maintain adsorbed hydroxyl groups on their surface, which is expected to be critical for the electrocatalytic properties of the materials. The insight gained from the surface analysis may serve as a paradigm for understanding the effect of the gas environment on the electrochemical performance and the electrical conductivity of the electrodes.

  11. Alloying Au surface with Pd reduces the intrinsic activity in catalyzing CO oxidation

    KAUST Repository

    Qian, Kun; Luo, Liangfeng; Jiang, Zhiquan; Huang, Weixin

    2016-01-01

    were evaluated. The formation of Au-Pd alloy particles was identified. The Au-Pd alloy particles exhibit enhanced dispersions on SiO2 than Au particles. Charge transfer from Pd to Au within Au-Pd alloy particles. Isolated Pd atoms dominate the surface

  12. Electroactive biofilms of sulphate reducing bacteria

    International Nuclear Information System (INIS)

    Cordas, Cristina M.; Guerra, L. Tiago; Xavier, Catarina; Moura, Jose J.G.

    2008-01-01

    Biofilms formed from a pure strain of Desulfovibrio desulfuricans 27774 on stainless steel and graphite polarised surfaces were studied. The polarisation conditions applied were -0.4 V vs. SCE for different times. A cathodic current related with the biofilms growth was observed with a maximum intensity of -270 mA m -2 that remained stable for several days using graphite electrodes. These sulphate reducing bacteria biofilms present electrocatalytic activity towards hydrogen and oxygen reduction reactions. Electrode polarisation has a selective effect on the catalytic activity. The biofilms were also observed by scanning electronic microscopy revealing the formation of homogeneous films on the surfaces

  13. Angle-dependent magnetoresistance and quantum oscillations in high-mobility semimetal LuPtBi

    KAUST Repository

    Xu, Guizhou; Hou, Zhipeng; Wang, Yue; Zhang, Xiaoming; Zhang, Hongwei; Liu, Enke; Xi, X; Xu, Feng; Wu, Guangheng; Zhang, Xixiang; Wang, Wenhong

    2017-01-01

    The recent discovery of ultrahigh mobility and large positive magnetoresistance in topologically non-trivial Half-Heusler semimetal LuPtBi provides a unique playground for studying exotic physics and significant perspective for device applications. As an fcc-structured electron-hole-compensated semimetal, LuPtBi theoretically exhibits six symmetrically arranged anisotropic electron Fermi pockets and two nearly-spherical hole pockets, offering the opportunity to explore the physics of Fermi surface with a simple angle-related magnetotransport properties. In this work, through the angle-dependent transverse magnetoresistance measurements, in combination with high-field SdH quantum oscillations, we achieved to map out a Fermi surface with six anisotropic pockets in the high-temperature and low-field regime, and furthermore, identify a possible magnetic field driven Fermi surface change at lower temperatures. Reasons account for the Fermi surface change in LuPtBi are discussed in terms of the field-induced electron evacuation due to Landau quantization.

  14. Angle-dependent magnetoresistance and quantum oscillations in high-mobility semimetal LuPtBi

    KAUST Repository

    Xu, Guizhou

    2017-03-14

    The recent discovery of ultrahigh mobility and large positive magnetoresistance in topologically non-trivial Half-Heusler semimetal LuPtBi provides a unique playground for studying exotic physics and significant perspective for device applications. As an fcc-structured electron-hole-compensated semimetal, LuPtBi theoretically exhibits six symmetrically arranged anisotropic electron Fermi pockets and two nearly-spherical hole pockets, offering the opportunity to explore the physics of Fermi surface with a simple angle-related magnetotransport properties. In this work, through the angle-dependent transverse magnetoresistance measurements, in combination with high-field SdH quantum oscillations, we achieved to map out a Fermi surface with six anisotropic pockets in the high-temperature and low-field regime, and furthermore, identify a possible magnetic field driven Fermi surface change at lower temperatures. Reasons account for the Fermi surface change in LuPtBi are discussed in terms of the field-induced electron evacuation due to Landau quantization.

  15. Tailoring surface groups of carbon quantum dots to improve photoluminescence behaviors

    International Nuclear Information System (INIS)

    Tian, Ruixue; Hu, Shengliang; Wu, Lingling; Chang, Qing; Yang, Jinlong; Liu, Jun

    2014-01-01

    Highlights: • We develop a facile and green method to tailor surface groups. • Photoluminescence behaviors of carbon quantum dots are improved by tailoring their surface groups. • Highly luminescent efficiency is produced by amino-hydrothermal treatment of reduced carbon quantum dots. - Abstract: A facile and green method to tailor surface groups of carbon quantum dots (CQDs) is developed by hydrothermal treatment in an autoclave. The photoluminescence (PL) behaviors of CQDs depend on the types of surface groups. Highly efficient photoluminescence is obtained through amino-hydrothermal treatment of the CQDs reduced by NaBH 4 . The effects of surface groups on PL behavior are attributed to the degrees of energy band bending induced by surface groups

  16. Elaboration of highly hydrophobic polymeric surface — a potential strategy to reduce the adhesion of pathogenic bacteria?

    Energy Technology Data Exchange (ETDEWEB)

    Poncin-Epaillard, F., E-mail: fabienne.poncin-epaillard@univ-lemans.fr [Institut des Molécules et Matériaux du Mans (IMMM), département Polymères, Colloïdes et Interfaces, UMR CNRS 6283 Université LUNAM, av. O. Messiaen, 72085 Le Mans (France); Herry, J.M. [INRA-AgroParisTech, UMR 1319 MICALIS, équipe B2HM, 25 avenue de la République, 91300 Massy (France); Marmey, P.; Legeay, G. [CTTM, 20 rue Thalès de Milet 72000 Le Mans (France); Debarnot, D. [Institut des Molécules et Matériaux du Mans (IMMM), département Polymères, Colloïdes et Interfaces, UMR CNRS 6283 Université LUNAM, av. O. Messiaen, 72085 Le Mans (France); Bellon-Fontaine, M.N. [INRA-AgroParisTech, UMR 1319 MICALIS, équipe B2HM, 25 avenue de la République, 91300 Massy (France)

    2013-04-01

    Different polymeric surfaces have been modified in order to reach a high hydrophobic character, indeed the superhydrophobicity property. For this purpose, polypropylene and polystyrene have been treated by RF or μwaves CF{sub 4} plasma with different volumes, the results were compared according to the density of injected power. The effect of pretreatment such as mechanical abrasion or plasma activation was also studied. The modified surfaces were shown as hydrophobic, or even superhydrophobic depending of defects density. They were characterized by measurement of wettability and roughness at different scales, i.e. macroscopic, mesoscopic and atomic. It has been shown that a homogeneous surface at the macroscopic scale could be heterogeneous at lower mesoscopic scale. This was associated with the crystallinity of the material. The bioadhesion tests were performed with Gram positive and negative pathogenic strains: Listeria monocytogenes, Pseudomonas aeruginosa and Hafnia alvei. They have demonstrated an antibacterial efficiency of very hydrophobic and amorphous PS treated for all strains tested and a strain-dependent efficiency with modified PP surface being very heterogeneous at the mesoscopic scale. Thus, these biological results pointed out not only the respective role of the surface chemistry and topography in bacterial adhesion, but also the dependence on the peaks and valley distribution at bacteria dimension scale. Highlights: ► Simple, eco-friendly modification of polymers leading to highly hydrophobic property ► Plasma treatment inducing surface fluorination and roughness ► Study of non-adhesion of different types of bacteria onto such polymeric surfaces ► Dependence of their non-adhesion on surface topography whatever their characteristics.

  17. Iron oxide surfaces

    Science.gov (United States)

    Parkinson, Gareth S.

    2016-03-01

    The current status of knowledge regarding the surfaces of the iron oxides, magnetite (Fe3O4), maghemite (γ-Fe2O3), haematite (α-Fe2O3), and wüstite (Fe1-xO) is reviewed. The paper starts with a summary of applications where iron oxide surfaces play a major role, including corrosion, catalysis, spintronics, magnetic nanoparticles (MNPs), biomedicine, photoelectrochemical water splitting and groundwater remediation. The bulk structure and properties are then briefly presented; each compound is based on a close-packed anion lattice, with a different distribution and oxidation state of the Fe cations in interstitial sites. The bulk defect chemistry is dominated by cation vacancies and interstitials (not oxygen vacancies) and this provides the context to understand iron oxide surfaces, which represent the front line in reduction and oxidation processes. Fe diffuses in and out from the bulk in response to the O2 chemical potential, forming sometimes complex intermediate phases at the surface. For example, α-Fe2O3 adopts Fe3O4-like surfaces in reducing conditions, and Fe3O4 adopts Fe1-xO-like structures in further reducing conditions still. It is argued that known bulk defect structures are an excellent starting point in building models for iron oxide surfaces. The atomic-scale structure of the low-index surfaces of iron oxides is the major focus of this review. Fe3O4 is the most studied iron oxide in surface science, primarily because its stability range corresponds nicely to the ultra-high vacuum environment. It is also an electrical conductor, which makes it straightforward to study with the most commonly used surface science methods such as photoemission spectroscopies (XPS, UPS) and scanning tunneling microscopy (STM). The impact of the surfaces on the measurement of bulk properties such as magnetism, the Verwey transition and the (predicted) half-metallicity is discussed. The best understood iron oxide surface at present is probably Fe3O4(100); the structure is

  18. Bioinspired surfaces for turbulent drag reduction.

    Science.gov (United States)

    Golovin, Kevin B; Gose, James W; Perlin, Marc; Ceccio, Steven L; Tuteja, Anish

    2016-08-06

    In this review, we discuss how superhydrophobic surfaces (SHSs) can provide friction drag reduction in turbulent flow. Whereas biomimetic SHSs are known to reduce drag in laminar flow, turbulence adds many new challenges. We first provide an overview on designing SHSs, and how these surfaces can cause slip in the laminar regime. We then discuss recent studies evaluating drag on SHSs in turbulent flow, both computationally and experimentally. The effects of streamwise and spanwise slip for canonical, structured surfaces are well characterized by direct numerical simulations, and several experimental studies have validated these results. However, the complex and hierarchical textures of scalable SHSs that can be applied over large areas generate additional complications. Many studies on such surfaces have measured no drag reduction, or even a drag increase in turbulent flow. We discuss how surface wettability, roughness effects and some newly found scaling laws can help explain these varied results. Overall, we discuss how, to effectively reduce drag in turbulent flow, an SHS should have: preferentially streamwise-aligned features to enhance favourable slip, a capillary resistance of the order of megapascals, and a roughness no larger than 0.5, when non-dimensionalized by the viscous length scale.This article is part of the themed issue 'Bioinspired hierarchically structured surfaces for green science'. © 2016 The Author(s).

  19. Contact Angle Hysteresis on Graphene Surfaces and Hysteresis-free Behavior on Oil-infused Graphite Surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Cyuan-Jhang; Li, Yueh-Feng [Department of Chemical and Materials Engineering, National Central University, Jhongli 320, Taiwan (China); Woon, Wei-Yen [Department of Physics, National Central University, Jhongli 320, Taiwan (China); Sheng, Yu-Jane, E-mail: yjsheng@ntu.edu.tw [Department of Chemical Engineering, National Taiwan University, Taipei 106, Taiwan (China); Tsao, Heng-Kwong, E-mail: hktsao@cc.ncu.edu.tw [Department of Chemical and Materials Engineering, National Central University, Jhongli 320, Taiwan (China); Department of Physics, National Central University, Jhongli 320, Taiwan (China)

    2016-11-01

    Highlights: • Contact angle hysteresis(CAH) on four graphitic surfacesisinvestigated. • The hysteresis loopof water drops on the polished graphite sheetshowsparticularly small receding contact angle. • The significant CAH observed on CVD graphene and highly oriented pyrolytic graphite is attributed mainly to adhesion hysteresis. • An oil-infused surface of a graphite sheet is produced by imbibition of hexadecane into its porous structure. • The hysteresis-free property for water drops on such a surface is examined and quantitatively explained. - Abstract: Contact angle hysteresis (CAH) on graphitic surfaces, including chemical vapor deposition (CVD) graphene, reduced electrophoretic deposition (EPD) graphene, highly oriented pyrolytic graphite (HOPG), and polished graphite sheet, has been investigated. The hysteresis loops of water drops on the first three samples are similar but the receding contact angle is particularly small for the polished graphite sheet.The significant CAH observed on CVD graphene and HOPG associated with atom-scale roughness has to be attributed mainly to adhesion hysteresis (surface relaxation), instead of roughness or defects.The difference of the wetting behavior among those four graphitic samples has been further demonstrated by hexadecane drops. On the surface of HOPG or CVD graphene,the contact line expands continuously with time, indicating total wetting for which the contact angle does not exist and contact line pinning disappears. In contrast, on the surface of reduced EPD graphene, spontaneous spreading is halted by spikes on it and partial wetting with small contact angle (θ≈4°) is obtained. On the surface of polished graphite sheet, the superlipophilicity and porous structure are demonstrated by imbibition and capillary rise of hexadecane. Consequently, an oil-infused graphite surface can be fabricated and the ultralow CAH of water (∆θ≈2°) is achieved.

  20. Decreased surface expression of the δ subunit of the GABAA receptor contributes to reduced tonic inhibition in dentate granule cells in a mouse model of fragile X syndrome.

    Science.gov (United States)

    Zhang, Nianhui; Peng, Zechun; Tong, Xiaoping; Lindemeyer, A Kerstin; Cetina, Yliana; Huang, Christine S; Olsen, Richard W; Otis, Thomas S; Houser, Carolyn R

    2017-11-01

    While numerous changes in the GABA system have been identified in models of Fragile X Syndrome (FXS), alterations in subunits of the GABA A receptors (GABA A Rs) that mediate tonic inhibition are particularly intriguing. Considering the key role of tonic inhibition in controlling neuronal excitability, reduced tonic inhibition could contribute to FXS-associated disorders such as hyperactivity, hypersensitivity, and increased seizure susceptibility. The current study has focused on the expression and function of the δ subunit of the GABA A R, a major subunit involved in tonic inhibition, in granule cells of the dentate gyrus in the Fmr1 knockout (KO) mouse model of FXS. Electrophysiological studies of dentate granule cells revealed a marked, nearly four-fold, decrease in tonic inhibition in the Fmr1 KO mice, as well as reduced effects of two δ subunit-preferring pharmacological agents, THIP and DS2, supporting the suggestion that δ subunit-containing GABA A Rs are compromised in the Fmr1 KO mice. Immunohistochemistry demonstrated a small but statistically significant decrease in δ subunit labeling in the molecular layer of the dentate gyrus in Fmr1 KO mice compared to wildtype (WT) littermates. The discrepancy between the large deficits in GABA-mediated tonic inhibition in granule cells in the Fmr1 KO mice and only modest reductions in immunolabeling of the δ subunit led to studies of surface expression of the δ subunit. Cross-linking experiments followed by Western blot analysis demonstrated a small, non-significant decrease in total δ subunit protein in the hippocampus of Fmr1 KO mice, but a four-fold decrease in surface expression of the δ subunit in these mice. No significant changes were observed in total or surface expression of the α4 subunit protein, a major partner of the δ subunit in the forebrain. Postembedding immunogold labeling for the δ subunit demonstrated a large, three-fold, decrease in the number of symmetric synapses with

  1. Surface thiolation of silicon for antifouling application.

    Science.gov (United States)

    Zhang, Xiaoning; Gao, Pei; Hollimon, Valerie; Brodus, DaShan; Johnson, Arion; Hu, Hongmei

    2018-02-07

    Thiol groups grafted silicon surface was prepared as previously described. 1H,1H,2H,2H-perfluorodecanethiol (PFDT) molecules were then immobilized on such a surface through disulfide bonds formation. To investigate the contribution of PFDT coating to antifouling, the adhesion behaviors of Botryococcus braunii (B. braunii) and Escherichia coli (E. coli) were studied through biofouling assays in the laboratory. The representative microscope images suggest reduced B. braunii and E. coli accumulation densities on PFDT integrated silicon substrate. However, the antifouling performance of PFDT integrated silicon substrate decreased over time. By incubating the aged substrate in 10 mM TCEP·HCl solution for 1 h, the fouled PFDT coating could be removed as the disulfide bonds were cleaved, resulting in reduced absorption of algal cells and exposure of non-fouled silicon substrate surface. Our results indicate that the thiol-terminated substrate can be potentially useful for restoring the fouled surface, as well as maximizing the effective usage of the substrate.

  2. Evidence-based playground design

    DEFF Research Database (Denmark)

    Refshauge, Anne Dahl; Stigsdotter, Ulrika K.; Lamm, Bettina

    2015-01-01

    , best practice, and the theories of Affordances and Behaviour Settings. A post-occupancy evaluation was carried out through a questionnaire survey and observation studies, which revealed that a majority of the potential evidence-based affordances were actualised, and that the application of the theories...

  3. Interactive Playgrounds for Children

    NARCIS (Netherlands)

    Poppe, Ronald Walter; van Delden, Robertus Wilhelmus; Moreno Celleri, Alejandro Manuel; Reidsma, Dennis; Nijholt, A.; Nijholt, Antinus

    Play is an important factor in the life of children. It plays a role in their cognitive, social, and physical development, and provides entertaining and fulfilling activities in itself. As with any field of human endeavor, interactive technology has a huge potential for transforming and enhancing

  4. Hummingbirds Visit the Playground.

    Science.gov (United States)

    Ard, Linda; Wilkerson, Kristen

    1996-01-01

    Tells how hummingbirds can serve as a source of information and fun for children, including a rationale for attracting and teaching about hummingbirds and the outdoors. Explains that children need first-hand knowledge of nature and gives details on attracting hummingbirds and selecting safe plants for a hummingbird garden. (BGC)

  5. Playground Safety (For Parents)

    Science.gov (United States)

    ... Parents Parents site Sitio para padres General Health Growth & Development Infections Diseases & Conditions Pregnancy & Baby Nutrition & Fitness Emotions & ... designed for three different age groups: infants and toddlers under 2, 2- to 5-year-olds (preschoolers), ...

  6. Investigations of the surface conductivity of silicon dioxide and methods to reduce it

    NARCIS (Netherlands)

    Voorthuyzen, J.A.; Keskin, K.; Bergveld, Piet

    1987-01-01

    In this paper we describe our investigations of the electrical conductivity of the silicon dioxide-air interface. It appears that this conductivity is caused by the adsorption of water vapour on the oxide surface and strongly depends on the relative humidity of the surrounding air. Considering this

  7. Spectral force analysis using atomic force microscopy reveals the importance of surface heterogeneity in bacterial and colloid adhesion to engineered surfaces.

    Science.gov (United States)

    Ma, Huilian; Winslow, Charles J; Logan, Bruce E

    2008-04-01

    Coatings developed to reduce biofouling of engineered surfaces do not always perform as expected based on their native properties. One reason is that a relatively small number of highly adhesive sites, or the heterogeneity of the coated surface, may control the overall response of the system to initial bacterial deposition. It is shown here using an approach we call spectral force analysis (SFA), based on force volume imaging of the surface with atomic force microscopy, that the behavior of surfaces and coatings can be better understood relative to bacterial adhesion. The application of vapor deposited TiO(2) metal oxide increased bacterial and colloid adhesion, but coating the surface with silica oxide reduced adhesion in a manner consistent with SFA based on analysis of the "stickiest" sites. Application of a TiO(2)-based paint to a surface produced a relatively non-fouling surface. Addition of a hydrophilic layer coating to this surface should have decreased fouling. However, it was observed that this coating actually increased fouling. Using SFA it was shown that the reason for the increased adhesion of bacteria and particles to the hydrophilic layer was that the surface produced by this coating was highly heterogeneous, resulting in a small number of sites that created a stickier surface. These results show that while it is important to manufacture surfaces with coatings that are relatively non-adhesive to bacteria, it is also essential that these coatings have a highly uniform surface chemistry.

  8. Incorporating Skew into RMS Surface Roughness Probability Distribution

    Science.gov (United States)

    Stahl, Mark T.; Stahl, H. Philip.

    2013-01-01

    The standard treatment of RMS surface roughness data is the application of a Gaussian probability distribution. This handling of surface roughness ignores the skew present in the surface and overestimates the most probable RMS of the surface, the mode. Using experimental data we confirm the Gaussian distribution overestimates the mode and application of an asymmetric distribution provides a better fit. Implementing the proposed asymmetric distribution into the optical manufacturing process would reduce the polishing time required to meet surface roughness specifications.

  9. Surface coating of siRNA-peptidomimetic nano-self-assemblies with anionic lipid bilayers: enhanced gene silencing and reduced adverse effects in vitro

    Science.gov (United States)

    Zeng, Xianghui; de Groot, Anne Marit; Sijts, Alice J. A. M.; Broere, Femke; Oude Blenke, Erik; Colombo, Stefano; van Eden, Willem; Franzyk, Henrik; Nielsen, Hanne Mørck; Foged, Camilla

    2015-11-01

    Cationic vectors have demonstrated the potential to facilitate intracellular delivery of therapeutic oligonucleotides. However, enhanced transfection efficiency is usually associated with adverse effects, which also proves to be a challenge for vectors based on cationic peptides. In this study a series of proteolytically stable palmitoylated α-peptide/β-peptoid peptidomimetics with a systematically varied number of repeating lysine and homoarginine residues was shown to self-assemble with small interfering RNA (siRNA). The resulting well-defined nanocomplexes were coated with anionic lipids giving rise to net anionic liposomes. These complexes and the corresponding liposomes were optimized towards efficient gene silencing and low adverse effects. The optimal anionic liposomes mediated a high silencing effect, which was comparable to that of the control (cationic Lipofectamine 2000), and did not display any noticeable cytotoxicity and immunogenicity in vitro. In contrast, the corresponding nanocomplexes mediated a reduced silencing effect with a more narrow safety window. The surface coating with anionic lipid bilayers led to partial decomplexation of the siRNA-peptidomimetic nanocomplex core of the liposomes, which facilitated siRNA release. Additionally, the optimal anionic liposomes showed efficient intracellular uptake and endosomal escape. Therefore, these findings suggest that a more efficacious and safe formulation can be achieved by surface coating of the siRNA-peptidomimetic nano-self-assemblies with anionic lipid bilayers.Cationic vectors have demonstrated the potential to facilitate intracellular delivery of therapeutic oligonucleotides. However, enhanced transfection efficiency is usually associated with adverse effects, which also proves to be a challenge for vectors based on cationic peptides. In this study a series of proteolytically stable palmitoylated α-peptide/β-peptoid peptidomimetics with a systematically varied number of repeating lysine

  10. Reconstruction of surface impedance of an object located over a planar PEC surface

    International Nuclear Information System (INIS)

    Uenal, Guel Seda; Cayoeren, Mehmet; Tetik, Evrim

    2008-01-01

    A method for the determination of inhomogeneous surface impedance of an arbitrary shaped cylindrical object located over a perfectly conducting (PEC) plane is presented. The problem is reduced to the solution of an ill-posed integral equation by the use of single layer representation which is handled by Truncated Singular Value Decomposition (TSVD). The total field and its normal derivative on the boundary of the object which are required for the evaluation of the surface impedance are obtained through Nystroem method. The method can also be used in shape reconstruction by using the relation between the shape of a PEC object and its equivalent one in terms of the surface impedance. The numerical implementations yield quite satisfactory results.

  11. Simulation and preparation of surface EVA in reduced gravity at the Marseilles Bay subsea analogue sites

    Science.gov (United States)

    Weiss, P.; Gardette, B.; Chirié, B.; Collina-Girard, J.; Delauze, H. G.

    2012-12-01

    Extravehicular activity (EVA) of astronauts during space missions is simulated nowadays underwater in neutral buoyancy facilities. Certain aspects of weightlessness can be reproduced underwater by adding buoyancy to a diver-astronaut, therefore exposing the subject to the difficulties of working without gravity. Such tests were done at the COMEX' test pool in Marseilles in the 1980s to train for a French-Russian mission to the MIR station, for the development of the European HERMES shuttle and the COLUMBUS laboratory. However, space agencies are currently studying missions to other destinations than the International Space Station in orbit, such as the return to the Moon, NEO (near-Earth objects) or Mars. All these objects expose different gravities: Moon has one sixth of Earth's gravity, Mars has a third of Earth's gravity and asteroids have virtually no surface gravity; the astronaut "floats" above the ground. The preparation of such missions calls for a new concept in neutral buoyancy training, not on man-made structures, but on natural terrain, underwater, to simulate EVA operations such as sampling, locomotion or even anchoring in low gravity. Underwater sites can be used not only to simulate the reduced gravity that astronauts will experience during their field trips, also human factors like stress are more realistically reproduced in such environment. The Bay of Marseille hosts several underwater sites that can be used to simulate various geologic morphologies, such as sink-holes which can be used to simulate astronaut descends into craters, caves where explorations of lava tubes can be trained or monolithic rock structures that can be used to test anchoring devices (e.g., near Earth objects). Marseilles with its aerospace and maritime/offshore heritage hosts the necessary logistics and expertise that is needed to perform such simulations underwater in a safe manner (training of astronaut-divers in local test pools, research vessels, subsea robots and

  12. Minimal families of curves on surfaces

    KAUST Repository

    Lubbes, Niels

    2014-11-01

    A minimal family of curves on an embedded surface is defined as a 1-dimensional family of rational curves of minimal degree, which cover the surface. We classify such minimal families using constructive methods. This allows us to compute the minimal families of a given surface.The classification of minimal families of curves can be reduced to the classification of minimal families which cover weak Del Pezzo surfaces. We classify the minimal families of weak Del Pezzo surfaces and present a table with the number of minimal families of each weak Del Pezzo surface up to Weyl equivalence.As an application of this classification we generalize some results of Schicho. We classify algebraic surfaces that carry a family of conics. We determine the minimal lexicographic degree for the parametrization of a surface that carries at least 2 minimal families. © 2014 Elsevier B.V.

  13. Study on tribological properties of multi-layer surface texture on Babbitt alloys surface

    Science.gov (United States)

    Zhang, Dongya; Zhao, Feifei; Li, Yan; Li, Pengyang; Zeng, Qunfeng; Dong, Guangneng

    2016-12-01

    To improve tribological properties of Babbitt alloys, multi-layer surface texture consisted of the main grooves and secondary micro-dimples are fabricated on the Babbitt substrate through laser pulse ablation. The tribological behaviors of multi-layer surface texture are investigated using a rotating type pin-on-disc tribo-meter under variation sliding speeds, and the film pressure distributions on the textured surfaces are simulated using computational fluid dynamics (CFD) method for elucidating the possible mechanisms. The results suggest that: (i) the multi-layer surface texture can reduce friction coefficient of Babbitt alloy, which has lowest friction coefficient of 0.03, in case of the groove parameter of 300 μm width and 15% of area density; (ii) the improvement effect may be more sensitive to the groove area density and the siding speed, and the textured surface with lower area density has lower friction coefficient under high sliding speed. Based on the reasons of (i) the secondary micro-dimples on Babbitt alloy possesses a hydrophobicity surface and (ii) the CFD analysis indicates that main grooves enhancing hydrodynamic effect, thus the multi-layer surface texture is regarded as dramatically improve the lubricating properties of the Babbitt alloy.

  14. Interaction of the wood surface with metal ions. Part 3: The effects of light on chromium impregnated wood surface

    International Nuclear Information System (INIS)

    Stipta, J.; Németh, K.; Molnárné Hamvas, L.

    2004-01-01

    UV-light changes of untreated and chromium impregnated wood surface were investigated by absorption spectrophotometric methods. The properties of indifferent silicagel and celulose layers were to the behaviour of poplar and black locust surface. Chromic-ion-impregnation had no significant effect on the absorption spectra of these layers. On the other hand, hexavalent chromium was reduced and UV-light caused irreversible wood degradation. Surface treatment caused considerable modification in black locust

  15. N-doped structures and surface functional groups of reduced graphene oxide and their effect on the electrochemical performance of supercapacitor with organic electrolyte

    Science.gov (United States)

    Li, Shin-Ming; Yang, Shin-Yi; Wang, Yu-Sheng; Tsai, Hsiu-Ping; Tien, Hsi-Wen; Hsiao, Sheng-Tsung; Liao, Wei-Hao; Chang, Chien-Liang; Ma, Chen-Chi M.; Hu, Chi-Chang

    2015-03-01

    Nitrogen-doped reduced graphene oxide (N-rGO) has been synthesized using a simple, efficient method combining instant thermal exfoliation and covalent bond transformation from a melamine-graphene oxide mixture. The capacitive performance of N-rGO has been tested in both aqueous (0.5 M H2SO4) and organic (1 M tetraethyl-ammonium tetrafluoroborate (TEABF4) in propylene carbonate (PC)) electrolytes, which are compared with those obtained from thermal-reduced graphene oxide (T-rGO) and chemical-reduced graphene oxide (C-rGO). The contributions of scan-rate-independent (double-layer-like) and scan-rate-dependent (pseudo-capacitance-like) capacitance of all reduced graphene oxides in both aqueous and organic electrolytes were evaluated and compared. The results show that relatively rich oxygen-containing functional groups on C-rGO form significant ion-diffusion barrier, resulting in worse electrochemical responses in organic electrolyte. By contrast, the N-doped structures, large surface area, and lower density of oxygen-containing groups make N-rGO become a promising electrode material for organic electric double-layer capacitors (EDLCs). The capacitance rate-retention of N-rGO reaches 71.1% in 1 M TEABF4/PC electrolyte when the scan rate is elevated to 200 mVs-1, demonstrating that N-rGO improves the relatively low-power drawback of EDLCs in organic electrolytes. The specific energy and power of a symmetric N-rGO cell in the organic electrolyte reach 25 Wh kg-1 and 10 kW kg-1, respectively.

  16. High-Density Infrared Surface Treatments of Refractories

    Energy Technology Data Exchange (ETDEWEB)

    Tiegs, T.N.

    2005-03-31

    Refractory materials play a crucial role in all energy-intensive industries and are truly a crosscutting technology for the Industries of the Future (IOF). One of the major mechanisms for the degradation of refractories and a general decrease in their performance has been the penetration and corrosion by molten metals or glass. Methods and materials that would reduce the penetration, wetting, and corrosive chemistry would significantly improve refractory performance and also maintain the quality of the processed liquid, be it metal or glass. This report presents the results of an R&D project aimed at investigating the use of high-density infrared (HDI) heating to surface treat refractories to improve their performance. The project was a joint effort between Oak Ridge National Laboratory (ORNL) and the University of Missouri-Rolla (UMR). HDI is capable of heating the near-surface region of materials to very high temperatures where sintering, diffusion, and melting can occur. The intended benefits of HDI processing of refractories were to (1) reduce surface porosity (by essentially sealing the surface to prevent liquid penetration), (2) allow surface chemistry changes to be performed by bonding an adherent coating onto the underlying refractory (in order to inhibit wetting and/or improve corrosion resistance), and (3) produce noncontact refractories with high-emissivity surface coatings.

  17. Surface morphology of erbium silicide

    International Nuclear Information System (INIS)

    Lau, S.S.; Pai, C.S.; Wu, C.S.; Kuech, T.F.; Liu, B.X.

    1982-01-01

    The surface of rare-earth silicides (Er, Tb, etc.), formed by the reaction of thin-film metal layers with a silicon substrate, is typically dominated by deep penetrating, regularly shaped pits. These pits may have a detrimental effect on the electronic performance of low Schottky barrier height diodes utilizing such silicides on n-type Si. This study suggests that contamination at the metal-Si or silicide-Si interface is the primary cause of surface pitting. Surface pits may be reduced in density or eliminated entirely through either the use of Si substrate surfaces prepared under ultrahigh vacuum conditions prior to metal deposition and silicide formation or by means of ion irradiation techniques. Silicide layers formed by these techniques possess an almost planar morphology

  18. Shrinkage-reducing admixtures and early-age desiccation in cement pastes and mortars

    DEFF Research Database (Denmark)

    Bentz, D. P.; Geiker, Mette Rica; Hansen, Kurt Kielsgaard

    2001-01-01

    Fundamental studies of the early-age desiccation of cement-based materials with and without a shrinkage-reducing admixture (SRA) have been performed. Studies have been conducted under both sealed and drying conditions. Physical measurements include mass loss, surface tension, X-ray absorption to ...... to low w/c ratio concretes undergoing self-desiccation, in addition to their normal usage to reduce drying shrinkage.......Fundamental studies of the early-age desiccation of cement-based materials with and without a shrinkage-reducing admixture (SRA) have been performed. Studies have been conducted under both sealed and drying conditions. Physical measurements include mass loss, surface tension, X-ray absorption...

  19. Dynamic superhydrophobic behavior in scalable random textured polymeric surfaces

    Science.gov (United States)

    Moreira, David; Park, Sung-hoon; Lee, Sangeui; Verma, Neil; Bandaru, Prabhakar R.

    2016-03-01

    Superhydrophobic (SH) surfaces, created from hydrophobic materials with micro- or nano- roughness, trap air pockets in the interstices of the roughness, leading, in fluid flow conditions, to shear-free regions with finite interfacial fluid velocity and reduced resistance to flow. Significant attention has been given to SH conditions on ordered, periodic surfaces. However, in practical terms, random surfaces are more applicable due to their relative ease of fabrication. We investigate SH behavior on a novel durable polymeric rough surface created through a scalable roll-coating process with varying micro-scale roughness through velocity and pressure drop measurements. We introduce a new method to construct the velocity profile over SH surfaces with significant roughness in microchannels. Slip length was measured as a function of differing roughness and interstitial air conditions, with roughness and air fraction parameters obtained through direct visualization. The slip length was matched to scaling laws with good agreement. Roughness at high air fractions led to a reduced pressure drop and higher velocities, demonstrating the effectiveness of the considered surface in terms of reduced resistance to flow. We conclude that the observed air fraction under flow conditions is the primary factor determining the response in fluid flow. Such behavior correlated well with the hydrophobic or superhydrophobic response, indicating significant potential for practical use in enhancing fluid flow efficiency.

  20. Electroactive biofilms of sulphate reducing bacteria

    Energy Technology Data Exchange (ETDEWEB)

    Cordas, Cristina M.; Guerra, L. Tiago; Xavier, Catarina [Requimte-CQFB, Departamento de Quimica, Faculdade de Ciencias e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica (Portugal); Moura, Jose J.G. [Requimte-CQFB, Departamento de Quimica, Faculdade de Ciencias e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica (Portugal)], E-mail: jose.moura@dq.fct.unl.pt

    2008-12-01

    Biofilms formed from a pure strain of Desulfovibrio desulfuricans 27774 on stainless steel and graphite polarised surfaces were studied. The polarisation conditions applied were -0.4 V vs. SCE for different times. A cathodic current related with the biofilms growth was observed with a maximum intensity of -270 mA m{sup -2} that remained stable for several days using graphite electrodes. These sulphate reducing bacteria biofilms present electrocatalytic activity towards hydrogen and oxygen reduction reactions. Electrode polarisation has a selective effect on the catalytic activity. The biofilms were also observed by scanning electronic microscopy revealing the formation of homogeneous films on the surfaces.

  1. Neural and cortisol responses during play with human and computer partners in children with autism

    Science.gov (United States)

    Edmiston, Elliot Kale; Merkle, Kristen

    2015-01-01

    Children with autism spectrum disorder (ASD) exhibit impairment in reciprocal social interactions, including play, which can manifest as failure to show social preference or discrimination between social and nonsocial stimuli. To explore mechanisms underlying these deficits, we collected salivary cortisol from 42 children 8–12 years with ASD or typical development during a playground interaction with a confederate child. Participants underwent functional MRI during a prisoner’s dilemma game requiring cooperation or defection with a human (confederate) or computer partner. Search region of interest analyses were based on previous research (e.g. insula, amygdala, temporal parietal junction—TPJ). There were significant group differences in neural activation based on partner and response pattern. When playing with a human partner, children with ASD showed limited engagement of a social salience brain circuit during defection. Reduced insula activation during defection in the ASD children relative to TD children, regardless of partner type, was also a prominent finding. Insula and TPJ BOLD during defection was also associated with stress responsivity and behavior in the ASD group under playground conditions. Children with ASD engage social salience networks less than TD children during conditions of social salience, supporting a fundamental disturbance of social engagement. PMID:25552572

  2. Simplification and transformation of ASTM F1292 measurement procedure for fall accident injury criteria.

    Science.gov (United States)

    Kato, Maki; Shimodaira, Yoshie; Sato, Takeshi; Iida, Hiromi

    2014-01-01

    Protecting children from injuries caused by fall accidents from playground equipment is important. Therefore, measures toward minimizing the risk of fall accident injuries are required. The risk of injury can be evaluated using ASTM F1292. In this test, G-max and the HIC are used to estimate the risk of injury. However, the measurement procedure is too complicated for application to a large number of installed equipment. F1292 requires simplified by reducing the number of phases, even with a small risk of loss in accuracy. With this in mind, this study proposes a shortened measurement procedure and a transformation equation to estimate the risk as same as F1292. As the result of experiments, it was revealed that G-max and the HIC values for both procedures linearly increase with drop height. The differences in outcomes between the regression equations of the standardized procedure and those of the shortened procedure can be used as a correction value. They can be added to the value measured by the shortened procedure. This suggests that the combination of the shortened procedure and transformation equation would be equivalent to F1292, with the advantage of being more easily and efficiently applied to the evaluation of installed playground equipment.

  3. Modeling the influence of a reduced equator-to-pole sea surface temperature gradient on the distribution of water isotopes in the Eocene

    Science.gov (United States)

    Speelman, E. N.; Sewall, J. O.; Noone, D. C.; Huber, M.; Sinninghe Damsté, J. S.; Reichart, G.

    2009-12-01

    Proxy-based climate reconstructions suggest the existence of a strongly reduced equator-to-pole temperature gradient during most of the Early Eocene. With the realization that the Eocene Arctic Ocean was covered with enormous quantities of the free floating freshwater fern Azolla, new questions related to Eocene (global) hydrological cycling facilitating these blooms arose. Changes in hydrological cycling, as a consequence of a reduced temperature gradient, are expected to be most clearly reflected in the isotopic composition (D, 18O) of precipitation. The interpretation of water isotopic records to quantitatively estimate past precipitation patterns is, however, hampered by the lack of detailed information on changes in their spatial and temporal distribution. Using the isotope-enabled global circulation model, Community Atmosphere Model v.3 (isoCAM3), relationships between water isotopes and past climates can be simulated. Here we examine the influence of a reduced meridional sea surface temperature gradient on the spatial distribution of precipitation and its isotopic composition in an Eocene setting. Overall, our combination of Eocene climate forcings, with superimposed TEX86-derived SST estimates and elevated pCO2 concentrations, produces a climate that agrees well with proxy data in locations around the globe. It shows the presence of an intensified hydrological cycle with precipitation exceeding evaporation in the Arctic region. The Eocene model runs with a significantly reduced equator-to-pole temperature gradient in a warmer more humid world predict occurrence of less depleted precipitation, with δD values ranging only between 0 and -140‰ (as opposed to the present-day range of 0 to -300‰). Combining new results obtained from compound specific isotope analyses on terrestrially derived n-alkanes extracted from Eocene sediments, and model calculations, shows that the model not only captures the main features, but reproduces isotopic values

  4. Influence of pre-heating on the surface modification of powder-metallurgy processed cold-work tool steel during laser surface melting

    Energy Technology Data Exchange (ETDEWEB)

    Šturm, Roman, E-mail: roman.sturm@fs.uni-lj.si [University of Ljubljana, Faculty of Mechanical Engineering, Aškerčeva 6, 1000 Ljubljana (Slovenia); Štefanikova, Maria [University of Ljubljana, Faculty of Mechanical Engineering, Aškerčeva 6, 1000 Ljubljana (Slovenia); Steiner Petrovič, Darja [Institute of Metals and Technology, Lepi pot 11, 1000 Ljubljana (Slovenia)

    2015-01-15

    Graphical abstract: - Highlights: • Heat-treatment protocol for laser surface melting of cold-work tool steel is proposed. • The laser melted steel surface is hardened, and morphologically modified. • The pre-heating of substrate creates a crack-and pore-free steel surface. • The optimum pre-heating temperature is determined to be 350 °C. • Using pre-heating the quantity of retained austenite is reduced. - Abstract: In this study we determine the optimal parameters for surface modification using the laser surface melting of powder-metallurgy processed, vanadium-rich, cold-work tool steel. A combination of steel pre-heating, laser surface melting and a subsequent heat treatment creates a hardened and morphologically modified surface of the selected high-alloy tool steel. The pre-heating of the steel prior to the laser surface melting ensures a crack- and pore-free modified surface. Using a pre-heating temperature of 350 °C, the extremely fine microstructure, which typically evolves during the laser-melting, became slightly coarser and the volume fraction of retained austenite was reduced. In the laser-melted layer the highest values of microhardness were achieved in the specimens where a subsequent heat treatment at 550 °C was applied. The performed thermodynamic calculations were able to provide a very valuable assessment of the liquidus temperature and, especially, a prediction of the chemical composition as well as the precipitation and dissolution sequence for the carbides.

  5. Nanomechanical and nanotribological properties of plasma nanotextured superhydrophilic and superhydrophobic polymeric surfaces

    International Nuclear Information System (INIS)

    Skarmoutsou, A; Charitidis, C A; Gnanappa, A K; Tserepi, A; Gogolides, E

    2012-01-01

    Oxygen plasma-induced surface modification of polymethylmethacrylate (PMMA), under plasma conditions favouring (maximizing) roughness formation, has been shown to create textured surfaces of roughness size and morphology dependent on the plasma-treatment time and subsequent morphology stabilization procedure. Superhydrophobic or superhydrophilic surfaces can thus be obtained, with potential applications in antireflective self-cleaning surfaces, microfluidics, wetting–dewetting control, anti-icing etc, necessitating determination of their mechanical properties. In this study, nanoindentation is used to determine the reduced modulus and hardness of the surface, while nanoscratch tests are performed to measure the coefficient of friction. The data are combined to assess the wear behaviour of such surfaces as a first guide for their practical applications. Short-time plasma treatment slightly changes mechanical, tribological and wear properties compared to untreated PMMA. However, a significant decrease in the reduced modulus and hardness and an increase in the coefficient of friction are observed after long plasma-treatment times. The C 4 F 8 plasma deposited thin hydrophobic layer on the polymeric surfaces (untreated and treated) reveals good adhesion, while its mechanical properties are greatly influenced by the substrate; it is also found that it effectively protects the polymeric surfaces, reducing plastic deformation. (paper)

  6. Investigation of synthetic aperture methods in ultrasound surface imaging using elementary surface types.

    Science.gov (United States)

    Kerr, W; Pierce, S G; Rowe, P

    2016-12-01

    Synthetic aperture imaging methods have been employed widely in recent research in non-destructive testing (NDT), but uptake has been more limited in medical ultrasound imaging. Typically offering superior focussing power over more traditional phased array methods, these techniques have been employed in NDT applications to locate and characterise small defects within large samples, but have rarely been used to image surfaces. A desire to ultimately employ ultrasonic surface imaging for bone surface geometry measurement prior to surgical intervention motivates this research, and results are presented for initial laboratory trials of a surface reconstruction technique based on global thresholding of ultrasonic 3D point cloud data. In this study, representative geometry artefacts were imaged in the laboratory using two synthetic aperture techniques; the Total Focusing Method (TFM) and the Synthetic Aperture Focusing Technique (SAFT) employing full and narrow synthetic apertures, respectively. Three high precision metallic samples of known geometries (cuboid, sphere and cylinder) which featured a range of elementary surface primitives were imaged using a 5MHz, 128 element 1D phased array employing both SAFT and TFM approaches. The array was manipulated around the samples using a precision robotic positioning system, allowing for repeatable ultrasound derived 3D surface point clouds to be created. A global thresholding technique was then developed that allowed the extraction of the surface profiles, and these were compared with the known geometry samples to provide a quantitative measure of error of 3D surface reconstruction. The mean errors achieved with optimised SAFT imaging for the cuboidal, spherical and cylindrical samples were 1.3mm, 2.9mm and 2.0mm respectively, while those for TFM imaging were 3.7mm, 3.0mm and 3.1mm, respectively. These results were contrary to expectations given the higher information content associated with the TFM images. However, it was

  7. Characterizing the effects of regolith surface roughness on photoemission from surfaces in space

    Science.gov (United States)

    Dove, A.; Horanyi, M.; Wang, X.

    2017-12-01

    Surfaces of airless bodies and spacecraft in space are exposed to a variety of charging environments. A balance of currents due to plasma bombardment, photoemission, electron and ion emission and collection, and secondary electron emission determines the surface's charge. Photoelectron emission is the dominant charging process on sunlit surfaces in the inner solar system due to the intense solar UV radiation. This can result in a net positive surface potential, with a cloud of photoelectrons immediately above the surface, called the photoelectron sheath. Conversely, the unlit side of the body will charge negatively due the collection of the fast-moving solar wind electrons. The interaction of charged dust grains with these positively and negatively charged surfaces, and within the photoelectron and plasma sheaths may explain the occurrence of dust lofting, levitation and transport above the lunar surface. The surface potential of exposed objects is also dependent on the material properties of their surfaces. Composition and particle size primarily affect the quantum efficiency of photoelectron generation; however, surface roughness can also control the charging process. In order to characterize these effects, we have conducted laboratory experiments to examine the role of surface roughness in generating photoelectrons in dedicated laboratory experiments using solid and dusty surfaces of the same composition (CeO2), and initial comparisons with JSC-1 lunar simulant. Using Langmuir probe measurements, we explore the measured potentials above insulating surfaces exposed to UV and an electric field, and we show that the photoemission current from a dusty surface is largely reduced due to its higher surface roughness, which causes a significant fraction of the emitted photoelectrons to be re-absorbed within the surface. We will discuss these results in context of similar situations on planetary surfaces.

  8. Surface-Displayed IL-10 by Recombinant Lactobacillus plantarum Reduces Th1 Responses of RAW264.7 Cells Stimulated with Poly(I:C) or LPS.

    Science.gov (United States)

    Cai, Ruopeng; Jiang, Yanlong; Yang, Wei; Yang, Wentao; Shi, Shaohua; Shi, Chunwei; Hu, Jingtao; Gu, Wei; Ye, Liping; Zhou, Fangyu; Gong, Qinglong; Han, Wenyu; Yang, Guilian; Wang, Chunfeng

    2016-02-01

    Recently, poly-γ-glutamic acid synthetase A (pgsA) has been applied to display exogenous proteins on the surface of Lactobacillus casei or Lactococcus lactis, which results in a surfacedisplayed component of bacteria. However, the ability of carrying genes encoded by plasmids and the expression efficiency of recombinant bacteria can be somewhat affected by the longer gene length of pgsA (1,143 bp); therefore, a truncated gene, pgsA, was generated based on the characteristics of pgsA by computational analysis. Using murine IL-10 as an exogenous gene, recombinant Lactobacillus plantarum was constructed and the capacity of the surface-displayed protein and functional differences between exogenous proteins expressed by these strains were evaluated. Surface expression of IL-10 on both recombinant bacteria with anchorins and the higher expression levels in L. plantarum-pgsA'-IL-10 were confirmed by western blot assay. Most importantly, up-regulation of IL-1β, IL-6, TNF-α, IFN-γ, and the nuclear transcription factor NF-κB p65 in RAW264.7 cells after stimulation with Poly(I:C) or LPS was exacerbated after co-culture with L. plantarum-pgsA. By contrast, IL-10 expressed by these recombinant strains could reduce these factors, and the expression of these factors was associated with recombinant strains that expressed anchorin (especially in L. plantarum-pgsA'-IL-10) and was significantly lower compared with the anchorin-free strains. These findings indicated that exogenous proteins could be successfully displayed on the surface of L. plantarum by pgsA or pgsA', and the expression of recombinant bacteria with pgsA' was superior compared with bacteria with pgsA.

  9. The role of the surface environment in healthcare-associated infections.

    Science.gov (United States)

    Weber, David J; Anderson, Deverick; Rutala, William A

    2013-08-01

    This article reviews the evidence demonstrating the importance of contamination of hospital surfaces in the transmission of healthcare-associated pathogens and interventions scientifically demonstrated to reduce the levels of microbial contamination and decrease healthcare-associated infections. The contaminated surface environment in hospitals plays an important role in the transmission of methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant Enterococcus spp. (VRE), Clostridium difficile, Acinetobacter spp., and norovirus. Improved surface cleaning and disinfection can reduce transmission of these pathogens. 'No-touch' methods of room disinfection (i.e., devices which produce ultraviolet light or hydrogen peroxide) and 'self-disinfecting' surfaces (e.g., copper) also show promise to decrease contamination and reduce healthcare-associated infections. Hospital surfaces are frequently contaminated with important healthcare-associated pathogens. Contact with the contaminated environment by healthcare personnel is equally as likely as direct contact with a patient to lead to contamination of the healthcare provider's hands or gloves that may result in patient-to-patient transmission of nosocomial pathogens. Admission to a room previously occupied by a patient with MRSA, VRE, Acinetobacter, or C. difficile increases the risk for the subsequent patient admitted to the room to acquire the pathogen. Improved cleaning and disinfection of room surfaces decreases the risk of healthcare-associated infections.

  10. Increase globe artichoke cropping sustainability using sub-surface drip-irrigation systems in a Mediterranean coastal area for reducing groundwater withdrawal

    Science.gov (United States)

    Mantino, Alberto; Marchina, Chiara; Bonari, Enrico; Fabbrizzi, Alessandro; Rossetto, Rudy

    2017-04-01

    suitability of SDI for globe artichoke cultivation, reducing the water consumption, while maintaining (or even increasing) crop production and (ii) assess the crop water use efficiency respect to surface drip-irrigation. The field test is located in Venturina (Italy) and it covers a surface of 4 ha. The soil is characterized by sandy-loam texture, 1.72% of organic matter at 7.81 pH. Groundwater is the main source of supply for irrigation. By the chemical point of view, a monitoring campaign in spring 2016 showed a neutral pH of 7.2, electrical conductivity of 1363 μS/cm, 373 and 243 mg/l of total sulphate and carbonate, respectively, thus demonstrating the suitability of groundwater for SDI application. The SDI system was implemented at the beginning of September 2016. The sub-surface buried pipelines, were placed at 0.25 m depth, with emitters spaced 0.5 m. The distance between pipelines was 1.5 m, according to globe artichoke layout (1.5 m between rows, 1 m in-row spacing). Surface-buried tubes were placed in an area about 0.75 ha wide for the comparison with SDI. Artichoke var. Terom were transplanted after the SDI operation test. In the next 3 years, both crop productivity and water use will be assessed. Results will be presented and discussed with the whole farmer's community. Acknowledgement This paper is presented within the framework of the project LIFE REWAT, which has received funding from the LIFE Programme of the European Union Grant Agreement LIFE14 ENV/IT/001290.

  11. Friction behavior of nano-textured polyimide surfaces measured by AFM colloidal probe

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Xiaoliang [College of Equipment Manufacturing, Hebei University of Engineering, Handan 056038 (China); State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Wu, Chunxia; Che, Hongwei; Hou, Junxian [College of Equipment Manufacturing, Hebei University of Engineering, Handan 056038 (China); Jia, Junhong, E-mail: jhjia@licp.cas.cn [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000 (China)

    2014-11-30

    Highlights: • Flat PI film and nano-textured PI film were prepared by spin-coating process. • The nano-textured PI surface has effectively reduced the adhesion and friction. • Friction increased with the increasing of contact area and adhesion. • The growth rate of friction decreased with the increasing of applied load. - Abstract: Flat polyimide (PI) film and silicon dioxide nanoparticle-textured PI film were prepared by means of the spin-coating technique. The adhesion and friction properties of the flat PI surface and nano-textured PI surface were investigated by a series of Atomic force microscope (AFM) colloidal probes. Experimental results revealed that the nano-textured PI surface can significantly reduce the adhesive force and friction force, compared with the flat PI surface. The main reason is that the nano-textures can reduce the contact area between the sample surface and colloidal probe. The effect of colloidal probe size on the friction behavior of the flat and nano-textured PI surfaces was evaluated. The adhesive force and friction force of nano-textured PI surface were increased with the increasing of the size of interacting pairs (AFM colloidal probe) due to the increased contact area. Moreover, the friction forces of flat and nano-textured PI surfaces were increased with applied load and sliding velocity.

  12. Citric acid modifies surface properties of commercial CeO{sub 2} nanoparticles reducing their toxicity and cerium uptake in radish (Raphanus sativus) seedlings

    Energy Technology Data Exchange (ETDEWEB)

    Trujillo-Reyes, J. [Chemistry Department, The University of Texas at El Paso, 500 West University Av., El Paso, TX 79968 (United States); Vilchis-Nestor, A.R. [Centro Conjunto de Investigación en Química Sustentable UAEM—UNAM, Carretera Toluca—Atlacomulco km 14.5, San Cayetano, CP 50200 Toluca, Estado de México (Mexico); Majumdar, S. [Chemistry Department, The University of Texas at El Paso, 500 West University Av., El Paso, TX 79968 (United States); University of California Center for Environmental Implications of Nanotechnology (UC CEIN), The University of Texas at El Paso, 500 West University Av., El Paso, TX 79968 (United States); Peralta-Videa, J.R. [Chemistry Department, The University of Texas at El Paso, 500 West University Av., El Paso, TX 79968 (United States); Environmental Science and Engineering PhD program, The University of Texas at El Paso, 500 West University Ave., El Paso, TX 79968 (United States); University of California Center for Environmental Implications of Nanotechnology (UC CEIN), The University of Texas at El Paso, 500 West University Av., El Paso, TX 79968 (United States); Gardea-Torresdey, J.L., E-mail: jgardea@utep.edu [Chemistry Department, The University of Texas at El Paso, 500 West University Av., El Paso, TX 79968 (United States); Environmental Science and Engineering PhD program, The University of Texas at El Paso, 500 West University Ave., El Paso, TX 79968 (United States); University of California Center for Environmental Implications of Nanotechnology (UC CEIN), The University of Texas at El Paso, 500 West University Av., El Paso, TX 79968 (United States)

    2013-12-15

    Highlights: • The citric acid capping significantly reduced the ζ potential values. • As the amount of CA increased, thicker the layer surrounding the CeO{sub 2} NPs. • CeO{sub 2}/CA NPs had better distribution and small particle size than bare CeO{sub 2} NPs. • CeO{sub 2}/CA NPs decrease the Ce uptake by radish seedlings. -- Abstract: Little is known about the mobility, reactivity, and toxicity to plants of coated engineered nanoparticles (ENPs). Surface modification may change the interaction of ENPs with living organisms. This report describes surface changes in commercial CeO{sub 2} NPs coated with citric acid (CA) at molar ratios of 1:2, 1:3, 1:7, and 1:10 CeO{sub 2}:CA, and their effects on radish (Raphanus sativus) seed germination, cerium and nutrients uptake. All CeO{sub 2} NPs and their absorption by radish plants were characterized by TEM, DLS, and ICP-OES. Radish seeds were germinated in pristine and CA coated CeO{sub 2} NPs suspensions at 50 mg/L, 100 mg/L, and 200 mg/L. Deionized water and CA at 100 mg/L were used as controls. Results showed ζ potential values of 21.6 mV and −56 mV for the pristine and CA coated CeO{sub 2} NPs, respectively. TEM images showed denser layers surrounding the CeO{sub 2} NPs at higher CA concentrations, as well as better distribution and smaller particle sizes. None of the treatments affected seed germination. However, at 200 mg/L the CA coated NPs at 1:7 ratio produced significantly (p ≤ 0.05) more root biomass, increased water content and reduced by 94% the Ce uptake, compared to bare NPs. This suggests that CA coating decrease CeO{sub 2} NPs toxicity to plants.

  13. Water redistribution at the soil surface : ponding and surface runoff in flat areas

    NARCIS (Netherlands)

    Appels, W.M.

    2013-01-01

    In The Netherlands, one of the most important targets for the improvement of surface water quality as aimed for in the European Water Framework Directive, is the reduction of nutrient concentrations (both nitrogen and phosphorus). To identify the most suitable and effective measures for reducing the

  14. System and method for reducing combustion dynamics in a combustor

    Science.gov (United States)

    Uhm, Jong Ho; Johnson, Thomas Edward; Zuo, Baifang; York, William David

    2013-08-20

    A system for reducing combustion dynamics in a combustor includes an end cap having an upstream surface axially separated from a downstream surface, and tube bundles extend through the end cap. A diluent supply in fluid communication with the end cap provides diluent flow to the end cap. Diluent distributors circumferentially arranged inside at least one tube bundle extend downstream from the downstream surface and provide fluid communication for the diluent flow through the end cap. A method for reducing combustion dynamics in a combustor includes flowing fuel through tube bundles that extend axially through an end cap, flowing a diluent through diluent distributors into a combustion chamber, wherein the diluent distributors are circumferentially arranged inside at least one tube bundle and each diluent distributor extends downstream from the end cap, and forming a diluent barrier in the combustion chamber between at least one pair of adjacent tube bundles.

  15. Dynamics of ice nucleation on water repellent surfaces.

    Science.gov (United States)

    Alizadeh, Azar; Yamada, Masako; Li, Ri; Shang, Wen; Otta, Shourya; Zhong, Sheng; Ge, Liehui; Dhinojwala, Ali; Conway, Ken R; Bahadur, Vaibhav; Vinciquerra, A Joseph; Stephens, Brian; Blohm, Margaret L

    2012-02-14

    Prevention of ice accretion and adhesion on surfaces is relevant to many applications, leading to improved operation safety, increased energy efficiency, and cost reduction. Development of passive nonicing coatings is highly desirable, since current antiicing strategies are energy and cost intensive. Superhydrophobicity has been proposed as a lead passive nonicing strategy, yet the exact mechanism of delayed icing on these surfaces is not clearly understood. In this work, we present an in-depth analysis of ice formation dynamics upon water droplet impact on surfaces with different wettabilities. We experimentally demonstrate that ice nucleation under low-humidity conditions can be delayed through control of surface chemistry and texture. Combining infrared (IR) thermometry and high-speed photography, we observe that the reduction of water-surface contact area on superhydrophobic surfaces plays a dual role in delaying nucleation: first by reducing heat transfer and second by reducing the probability of heterogeneous nucleation at the water-substrate interface. This work also includes an analysis (based on classical nucleation theory) to estimate various homogeneous and heterogeneous nucleation rates in icing situations. The key finding is that ice nucleation delay on superhydrophobic surfaces is more prominent at moderate degrees of supercooling, while closer to the homogeneous nucleation temperature, bulk and air-water interface nucleation effects become equally important. The study presented here offers a comprehensive perspective on the efficacy of textured surfaces for nonicing applications.

  16. Pt nanoparticles embedded on reduced graphite oxide with excellent electrocatalytic properties

    Energy Technology Data Exchange (ETDEWEB)

    Saravanan, Gengan, E-mail: saravanan3che@gmail.com [Central University of Tamil Nadu, Department of Chemistry, Thiruvarur, 610101 (India); Mohan, Subramanian, E-mail: sanjnamohan@yahoo.com [EMFT Division, CSIR-Central Electrochemical Research Institute, Tamilnadu, Karaikudi 630 006 (India)

    2016-11-15

    Graphical abstract: RGO/Nano Pt: This study explore the electrocatalytic oxidation performance of reduced graphite oxide (RGO) anchored with nano Pt. This graphene composite reveal superior electrooxidation performance that is associated with the flexible RGO matrix and the uniform distribution of Pt particles, which enhances surface area, fast electron transfer, uniform particle size distribution; consequently, the RGO matrix provides more stability to Pt particles during electrooxidation process. Display Omitted - Highlights: • Greener electrochemical method applied to prepare well-dispersed Pt-rGO. • Pt-rGO large surface area excellent charge transfer better catalytic activity. • Low-cost highly efficient carbon-based electrodes for direct formic acid fuel cell. • rGO an excellent support to anchor Pt nanoparticles on its surface. • Pt-rGO distinctly enhanced current density towards formic acid electrooxidation. - Abstract: Economically viable electrochemical approach has been developed for the synthesis of Pt nanoparticles through electrodeposition technique on the surface of Reduced Graphite Oxide (RGO). Pt nanoparticles embedded Reduced Graphite Oxide on Glassy Carbon Electrode are employed (Pt-rGO/GCE) for electrooxidation of formic acid. Scanning Electron Microscopy (SEM) image and Transmission Electron Microscopy (TEM) image shows that reduced graphite oxide act as an excellent support to anchor the Pt nanoparticles. Cyclic voltammetry results confirmed that Pt-rGO/GCE enhanced current density as many folds than that of bare platinum electrode for electrooxidation of formic acid. X-ray diffraction (XRD) patterns for Pt-graphene composites illustrate that peaks at 69.15 and 23° for Pt (220) and graphene carbon (002) respectively. {sup 13}C NMR spectrum of the electrochemically reduced graphite oxide resonance contains only one peak at 133 ppm which retains graphitic sp{sup 2} carbon and does not contain any oxygenated carbon and the carbonyl

  17. Development of highly faceted reduced graphene oxide-coated copper oxide and copper nanoparticles on a copper foil surface

    Directory of Open Access Journals (Sweden)

    Rebeca Ortega-Amaya

    2016-07-01

    Full Text Available This work describes the formation of reduced graphene oxide-coated copper oxide and copper nanoparticles (rGO-Cu2ONPs, rGO-CuNPs on the surface of a copper foil supporting graphene oxide (GO at annealing temperatures of 200–1000 °C, under an Ar atmosphere. These hybrid nanostructures were developed from bare copper oxide nanoparticles which grew at an annealing temperature of 80 °C under nitrogen flux. The predominant phase as well as the particle size and shape strongly depend on the process temperature. Characterization with transmission electron microscopy and scanning electron microscopy indicates that Cu or Cu2O nanoparticles take rGO sheets from the rGO network to form core–shell Cu–rGO or Cu2O–rGO nanostructures. It is noted that such ones increase in size from 5 to 800 nm as the annealing temperature increases in the 200–1000 °C range. At 1000 °C, Cu nanoparticles develop a highly faceted morphology, displaying arm-like carbon nanorods that originate from different facets of the copper crystal structure.

  18. Impact of initial surface parameters on the final quality of laser micro-polished surfaces

    Science.gov (United States)

    Chow, Michael; Bordatchev, Evgueni V.; Knopf, George K.

    2012-03-01

    Laser micro-polishing (LμP) is a new laser-based microfabrication technology for improving surface quality during a finishing operation and for producing parts and surfaces with near-optical surface quality. The LμP process uses low power laser energy to melt a thin layer of material on the previously machined surface. The polishing effect is achieved as the molten material in the laser-material interaction zone flows from the elevated regions to the local minimum due to surface tension. This flow of molten material then forms a thin ultra-smooth layer on the top surface. The LμP is a complex thermo-dynamic process where the melting, flow and redistribution of molten material is significantly influenced by a variety of process parameters related to the laser, the travel motions and the material. The goal of this study is to analyze the impact of initial surface parameters on the final surface quality. Ball-end micromilling was used for preparing initial surface of samples from H13 tool steel that were polished using a Q-switched Nd:YAG laser. The height and width of micromilled scallops (waviness) were identified as dominant parameter affecting the quality of the LμPed surface. By adjusting process parameters, the Ra value of a surface, having a waviness period of 33 μm and a peak-to-valley value of 5.9 μm, was reduced from 499 nm to 301 nm, improving the final surface quality by 39.7%.

  19. Surface chemistry and bonding configuration of ultrananocrystalline diamond surfaces and their effects on nanotribological properties

    International Nuclear Information System (INIS)

    Sumant, A. V.; Grierson, D. S.; Carpick, R. W.; Gerbi, J. E.; Carlisle, J. A.; Auciello, O.

    2007-01-01

    We present a comprehensive study of surface composition and nanotribology for ultrananocrystalline diamond (UNCD) surfaces, including the influence of film nucleation on these properties. We describe a methodology to characterize the underside of the films as revealed by sacrificial etching of the underlying substrate. This enables the study of the morphology and composition resulting from the nucleation and initial growth of the films, as well as the characterization of nanotribological properties which are relevant for applications including micro-/nanoelectromechanical systems. We study the surface chemistry, bonding configuration, and nanotribological properties of both the topside and the underside of the film with synchrotron-based x-ray absorption near-edge structure spectroscopy to identify the bonding state of the carbon atoms, x-ray photoelectron spectroscopy to determine the surface chemical composition, Auger electron spectroscopy to further verify the composition and bonding configuration, and quantitative atomic force microscopy to study the nanoscale topography and nanotribological properties. The films were grown on SiO 2 after mechanically polishing the surface with detonation synthesized nanodiamond powder, followed by ultrasonication in a methanol solution containing additional nanodiamond powder. The sp 2 fraction, morphology, and chemistry of the as-etched underside are distinct from the topside, exhibiting a higher sp 2 fraction, some oxidized carbon, and a smoother morphology. The nanoscale single-asperity work of adhesion between a diamond nanotip and the as-etched UNCD underside is far lower than for a silicon-silicon interface (59.2±2 vs 826±186 mJ/m 2 , respectively). Exposure to atomic hydrogen dramatically reduces nanoscale adhesion to 10.2±0.4 mJ/m 2 , at the level of van der Waals' interactions and consistent with recent ab initio calculations. Friction is substantially reduced as well, demonstrating a direct link between the

  20. Silica micro- and nanoparticles reduce the toxicity of surfactant solutions.

    Science.gov (United States)

    Ríos, Francisco; Fernández-Arteaga, Alejandro; Fernández-Serrano, Mercedes; Jurado, Encarnación; Lechuga, Manuela

    2018-04-20

    In this work, the toxicity of hydrophilic fumed silica micro- and nanoparticles of various sizes (7 nm, 12 nm, and 50 μm) was evaluated using the luminescent bacteria Vibrio fischeri. In addition, the toxicity of an anionic surfactant solution (ether carboxylic acid), a nonionic surfactant solution (alkyl polyglucoside), and a binary (1:1) mixture of these solutions all containing these silica particles was evaluated. Furthermore, this work discusses the adsorption of surfactants onto particle surfaces and evaluates the effects of silica particles on the surface tension and critical micellar concentration (CMC) of these anionic and nonionic surfactants. It was determined that silica particles can be considered as non-toxic and that silica particles reduce the toxicity of surfactant solutions. Nevertheless, the toxicity reduction depends on the ionic character of the surfactants. Differences can be explained by the different adsorption behavior of surfactants onto the particle surface, which is weaker for nonionic surfactants than for anionic surfactants. Regarding the effects on surface tension, it was found that silica particles increased the surface activity of anionic surfactants and considerably reduced their CMC, whereas in the case of nonionic surfactants, the effects were reversed. Copyright © 2018 Elsevier B.V. All rights reserved.

  1. Terahertz emission from semi-insulating GaAs with octadecanthiol-passivated surface

    International Nuclear Information System (INIS)

    Wu, Xiaojun; Xu, Xinlong; Lu, Xinchao; Wang, Li

    2013-01-01

    Terahertz (THz) emission from octadecanthiol (ODT) passivated (1 0 0) surface of the semi-insulating GaAs was measured, and compared with those from the native oxidized and the fresh surfaces. It was shown that the self-assembled ODT monolayer can stabilize the GaAs (1 0 0) surface, and maintain a THz surface emission 1.4 times as efficient as the native oxidized surface under equal conditions. Surface passivation can reduce the built-in electric field in the depletion region of the GaAs (1 0 0), resulting in the suppression of the THz radiation to a different extent. Oxidation of GaAs surface reduces the THz amplitude mainly in the low-frequency region. These results indicate that GaAs can be made a more effective THz source by choosing molecular passivation technique. Conversely, the THz emission features such as polarity, amplitude, and phase from molecule-passivated surfaces may be used to characterize the attached molecules.

  2. Experimental Study on Tribological Properties of Laser Textured 45 Steel Surface

    Directory of Open Access Journals (Sweden)

    Li Zhi Peng

    2016-01-01

    Full Text Available In order to study the influence of pits’ size parameters on the tribological properties of textured friction pairs, using the Nd:YAG laser micro machining system and the “single pulse at the same point, interval more times” processing technics to process the pits on the surface of 45 steel. The dimension parameters of pits texture were obtained by orthogonal experimental design. The tribological experiment of GCr15 pin/45 steel disc was carried out by UMT-2 test machine. The surface morphology of the specimens was analyzed by using scanning electron microscopy. The experimental results show that the pits texture on the surface of 45 steel can effectively reduce the friction coefficient and the wear on the condition of oil-rich lubrication. The textured specimen with diameter 60μm, depth 6μm and surface density 10% has the lowest friction coefficient, and the friction coefficient is reduced by 21% compared with the smooth specimen. By analyzing the wear morphology on the surface of 45 steel, it is found that the surface of pits texture can obviously reduce the wear.

  3. Evidence of antibacterial activity on titanium surfaces through nanotextures

    Energy Technology Data Exchange (ETDEWEB)

    Seddiki, O.; Harnagea, C. [INRS – Centre Énergie, Matériaux et Télécommunications, Boulevard Lionel-Boulet, Varennes, Québec J3X 1S2 (Canada); Levesque, L.; Mantovani, D. [Laboratory for Biomaterials and Bioengineering (CRC-I), Dept Min-Met-Materials Engineering and Research Center CHU-Quebec, Laval University, Quebec City (Canada); Rosei, F., E-mail: rosei@emt.inrs.ca [INRS – Centre Énergie, Matériaux et Télécommunications, Boulevard Lionel-Boulet, Varennes, Québec J3X 1S2 (Canada); Center for Self-Assembled Chemical Structures, McGill University, H3A 2K6 Montreal, Quebec (Canada)

    2014-07-01

    Nosocomial infections (Nis) are a major concern for public health. As more and more of the pathogens responsible for these infections are antibiotic resistant, finding new ways to overcome them is a major challenge for biomedical research. We present a method to reduce Nis spreading by hindering bacterial adhesion in its very early stage. This is achieved by reducing the contact interface area between the bacterium and the surface by nanoengineering the surface topography. In particular, we studied the Escheria Coli adhesion on titanium surfaces exhibiting different morphologies, that were obtained by a combination of mechanical polishing and chemical etching. Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM) characterization revealed that the titanium surface is modified at both micro- and nano-scale. X-ray Photoelectron Spectroscopy (XPS) revealed that the surfaces have the same composition before and after piranha treatment, consisting mainly of TiO{sub 2}. Adhesion tests showed a significant reduction in bacterial accumulation on nanostructured surfaces that had the lowest roughness over large areas. SEM images acquired after bacterial culture on different titanium substrates confirmed that the polished titanium surface treated one hour in a piranha solution at a temperature of 25 °C has the lowest bacterial accumulation among all the surfaces tested. This suggests that the difference observed in bacterial adhesion between the different surfaces is due primarily to surface topography.

  4. Evidence of antibacterial activity on titanium surfaces through nanotextures

    International Nuclear Information System (INIS)

    Seddiki, O.; Harnagea, C.; Levesque, L.; Mantovani, D.; Rosei, F.

    2014-01-01

    Nosocomial infections (Nis) are a major concern for public health. As more and more of the pathogens responsible for these infections are antibiotic resistant, finding new ways to overcome them is a major challenge for biomedical research. We present a method to reduce Nis spreading by hindering bacterial adhesion in its very early stage. This is achieved by reducing the contact interface area between the bacterium and the surface by nanoengineering the surface topography. In particular, we studied the Escheria Coli adhesion on titanium surfaces exhibiting different morphologies, that were obtained by a combination of mechanical polishing and chemical etching. Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM) characterization revealed that the titanium surface is modified at both micro- and nano-scale. X-ray Photoelectron Spectroscopy (XPS) revealed that the surfaces have the same composition before and after piranha treatment, consisting mainly of TiO 2 . Adhesion tests showed a significant reduction in bacterial accumulation on nanostructured surfaces that had the lowest roughness over large areas. SEM images acquired after bacterial culture on different titanium substrates confirmed that the polished titanium surface treated one hour in a piranha solution at a temperature of 25 °C has the lowest bacterial accumulation among all the surfaces tested. This suggests that the difference observed in bacterial adhesion between the different surfaces is due primarily to surface topography.

  5. Theory of the surface dipole layer and of surface tension in liquids of charged particles

    International Nuclear Information System (INIS)

    Senatore, G.; Tosi, M.P.

    1980-01-01

    The problem of the surface density profiles and of the surface tension of a two-component liquid of charged particles in equilibrium with its vapour is examined. The exact equilibrium conditions for the profiles are given in terms of the inverse response functions of the inhomogeneous fluid, and alternative exact expressions for the surface tension are derived. The use of a density gradient expansion reduces the problem to knowledge of properties of a homogeneous charged fluid on a uniform neutralizing background, in which the total particle density and the charge density are independent variables. Additional simplifications are discussed for special cases for which a perturbative treatment of the surface charge density profile can be developed, and in particular for nearly symmetric ionic liquids and for simple liquid metals. (author)

  6. Preparation of potassium-reduced tantalum powders

    International Nuclear Information System (INIS)

    Kolosov, V.N.; Miroshnichenko, M.N.; Orlov, V.M.; Prokhorova, T.Yu.

    2005-01-01

    Characteristics of tantalum powders prepared by reduction of molten potassium heptafluorotantalate with liquid potassium are studied in a temperature range of 750 - 850 deg C using potassium chloride as a flux at a ratio of K 2 TaF 7 : KCl = 1, 2, and 3. The use of potassium as a reducing agent facilitates washing of tantalum powders for impurity salt removal, reduces sodium content and leakage currents in the anodes. As compared to sodium process, the potassium reduction results in a high yield of sponge material, a decrease in the specific surface area and yield of tantalum powder suitable for manufacture of capacitor anodes [ru

  7. Challenges in realizing ultraflat materials surfaces

    Directory of Open Access Journals (Sweden)

    Takashi Yatsui

    2013-12-01

    Full Text Available Ultraflat surface substrates are required to achieve an optimal performance of future optical, electronic, or optoelectronic devices for various applications, because such surfaces reduce the scattering loss of photons, electrons, or both at the surfaces and interfaces. In this paper, we review recent progress toward the realization of ultraflat materials surfaces. First, we review the development of surface-flattening techniques. Second, we briefly review the dressed photon–phonon (DPP, a nanometric quasiparticle that describes the coupled state of a photon, an electron, and a multimode-coherent phonon. Then, we review several recent developments based on DPP-photochemical etching and desorption processes, which have resulted in angstrom-scale flat surfaces. To confirm that the superior flatness of these surfaces that originated from the DPP process, we also review a simplified mathematical model that describes the scale-dependent effects of optical near-fields. Finally, we present the future outlook for these technologies.

  8. Influence of Surface Properties and Impact Conditions on Adhesion of Insect Residues

    Science.gov (United States)

    Wohl, Christopher J.; Smith, Joseph G.; Connell, John W.; Siochi, Emilie J.; Doss, Jereme R.; Shanahan, Michelle H.; Penner, Ronald K.

    2015-01-01

    Insect residues can cause premature transition to turbulent flow on laminar flow airfoils. Engineered surfaces that mitigate the adhesion of insect residues provide, therefore, a route to more efficient aerodynamics and reduced fuel burn rates. Areal coverage and heights of residues depend not only on surface properties, but also on impact conditions. We report high speed photography of fruit fly impacts at different angles of inclination on a rigid aluminum surface, optical microscopy and profilometry, and contact angle goniometry to support the design of engineered surfaces. For the polyurethane and epoxy coatings studied, some of which exhibited superhydrophobicity, it was determined that impact angle and surface compositions play critical roles in the efficacy of these surfaces to reduce insect residue adhesion.

  9. Reduced graphene oxide wrapped Ag nanostructures for enhanced SERS activity

    Science.gov (United States)

    Nair, Anju K.; Kala, M. S.; Thomas, Sabu; Kalarikkal, Nandakumar

    2018-04-01

    Graphene - metal nanoparticle hybrids have received great attention due to their unique electronic properties, large specific surface area, very high conductivity and more charge transfer. Thus, it is extremely advantages to develop a simple and efficient process to disperse metal nanostructures over the surface of graphene sheets. Herein, we report a hydrothermal assisted strategy for developing reduced graphene oxide /Ag nanomorphotypes (cube, wire) for surface enhanced Raman scattering (SERS) applications, considering the advantages of synergistic effect of graphene and plasmonic properties of Ag nanomorphotypes.

  10. Nanoparticle-Based Surface Modifications for Microtribology Control and Superhydrophobicity

    Science.gov (United States)

    Hurst, Kendall Matthew

    2010-11-01

    The emergence of miniaturization techniques for consumer electronics has brought forth the relatively new and exciting field of microelectromechanical systems (MEMS). However, due to the inherent forces that exist between surfaces at the micro- and nanoscale, scientists and semiconductor manufacturers are still struggling to improve the lifetime and reliability of complex microdevices. Due to the extremely large surface area-to-volume ratio of typical MEMS and microstructured surfaces, dominant interfacial forces exist which can be detrimental to their operational lifetime. In particular, van der Waals, capillary, and electrostatic forces contribute to the permanent adhesion, or stiction , of microfabricated surfaces. This strong adhesion force also contributes to the friction and wear of these silicon-based systems. The scope of this work was to examine the effect of utilizing nanoparticles as the basis for roughening surfaces for the purpose of creating films with anti-adhesive and/or superhydrophobic properties. All of the studies presented in this work are focused around a gas-expanded liquid (GXL) process that promotes the deposition of colloidal gold nanoparticles (AuNPs) into conformal thin films. The GXL particle deposition process is finalized by a critical point drying step which is advantageous to the microelectromechanical systems and semiconductor (IC) industries. In fact, preliminary results illustrated that the GXL particle deposition process can easily be integrated into current MEMS microfabrication processes. Thin films of AuNPs deposited onto the surfaces of silicon-based MEMS and tribology test devices were shown to have a dramatic effect on the adhesion of microstructures. In the various investigations, the apparent work of adhesion between surfaces was reduced by 2-4 orders of magnitude. This effect is greatly attributed to the roughening of the typically smooth silicon oxide surfaces which, in turn, dramatically decreases the "real are of

  11. Allowing for surface preparation in stress corrosion cracking modelling

    International Nuclear Information System (INIS)

    Berge, P.; Buisine, D.; Gelpi, A.

    1997-01-01

    When a 600 alloy component is significantly deformed during installation, by welding, rolling, bending, its stress corrosion cracking in Pressurized Water Nuclear Reactor's primary coolant, is significantly changed by the initial surface treatment. Therefore, the crack initiated time may be reduced by several orders of magnitude for certain surfaces preparations. Allowing for cold working of the surface, for which modelling is proposed, depends less on the degree of cold work then on the depths of the hardened layers. Honing hardens the metal over depths of about one micron for vessel head penetrations, for example, and has little influence on subsequent behaviour after the part deforms. On the other hand, coarser turning treatment produces cold worked layers which can reach several tens of microns and can very significantly reduce the initiation time compared to fine honing. So evaluation after depths of hardening is vital on test pieces for interpreting laboratory results as well as on service components for estimating their service life. Suppression by mechanical or chemical treatment of these layers, after deformation, seems to be the most appropriate solution for reducing over-stressing connected with surface treatment carried out before deformation. (author)

  12. Modeling the influence of a reduced equator-to-pole sea surface temperature gradient on the distribution of water isotopes in the Early/Middle Eocene

    Science.gov (United States)

    Speelman, Eveline N.; Sewall, Jacob O.; Noone, David; Huber, Matthew; von der Heydt, Anna; Damsté, Jaap Sinninghe; Reichart, Gert-Jan

    2010-09-01

    Proxy-based climate reconstructions suggest the existence of a strongly reduced equator-to-pole temperature gradient during the Azolla interval in the Early/Middle Eocene, compared to modern. Changes in the hydrological cycle, as a consequence of a reduced temperature gradient, are expected to be reflected in the isotopic composition of precipitation (δD, δ 18O). The interpretation of water isotopic records to quantitatively reconstruct past precipitation patterns is, however, hampered by a lack of detailed information on changes in their spatial and temporal distribution. Using the isotope-enabled version of the National Center for Atmospheric Research (NCAR) atmospheric general circulation model, Community Atmosphere Model v.3 (isoCAM3), relationships between water isotopes and past climates can be simulated. Here we examine the influence of an imposed reduced meridional sea surface temperature gradient on the spatial distribution of precipitation and its isotopic composition in an Early/Middle Eocene setting. As a result of the applied forcings, the Eocene simulation predicts the occurrence of less depleted high latitude precipitation, with δD values ranging only between 0 and -140‰ (compared to Present-day 0 to -300‰). Comparison with Early/Middle Eocene-age isotopic proxy data shows that the simulation accurately captures the main features of the spatial distribution of the isotopic composition of Early/Middle Eocene precipitation over land in conjunction with the aspects of the modeled Early/Middle Eocene climate. Hence, the included stable isotope module quantitatively supports the existence of a reduced meridional temperature gradient during this interval.

  13. Prime focus architectures for large space telescopes: reduce surfaces to save cost

    Science.gov (United States)

    Breckinridge, J. B.; Lillie, C. F.

    2016-07-01

    Conceptual architectures are now being developed to identify future directions for post JWST large space telescope systems to operate in the UV Optical and near IR regions of the spectrum. Here we show that the cost of optical surfaces within large aperture telescope/instrument systems can exceed $100M/reflection when expressed in terms of the aperture increase needed to over come internal absorption loss. We recommend a program in innovative optical design to minimize the number of surfaces by considering multiple functions for mirrors. An example is given using the Rowland circle imaging spectrometer systems for UV space science. With few exceptions, current space telescope architectures are based on systems optimized for ground-based astronomy. Both HST and JWST are classical "Cassegrain" telescopes derived from the ground-based tradition to co-locate the massive primary mirror and the instruments at the same end of the metrology structure. This requirement derives from the dual need to minimize observatory dome size and cost in the presence of the Earth's 1-g gravitational field. Space telescopes, however function in the zero gravity of space and the 1- g constraint is relieved to the advantage of astronomers. Here we suggest that a prime focus large aperture telescope system in space may have potentially have higher transmittance, better pointing, improved thermal and structural control, less internal polarization and broader wavelength coverage than Cassegrain telescopes. An example is given showing how UV astronomy telescopes use single optical elements for multiple functions and therefore have a minimum number of reflections.

  14. Optimal design for MRI surface coils

    International Nuclear Information System (INIS)

    Rivera, M.; Vaquero, J.J.; Santos, A.; Pozo, F. del; Ruiz-Cabello, J.

    1997-01-01

    To demonstrate the possibility of designing and constructing specific surface coils or antennae for MRI viewing of each particular tissue producing better results than those provided by a general purpose surface coil. The study was performed by the Bioengineering and Telemedicine Group of Madrid Polytechnical University and was carried out at the Pluridisciplinary Institute of the Universidad Complutense in Madrid, using a BMT-47/40 BIOSPEC resonance unit from Bruker. Surface coils were custom-designed and constructed for each region to be studied, and optimized to make the specimen excitation field as homogeneous as possible, in addition to reducing the brightness artifact. First, images were obtained of a round, water phantom measuring 50 mm in diameter, after which images of laboratory rats and rabbits were obtained. The images thus acquired were compared with the results obtained with the coil provided by the manufacturer of the equipment, and were found to be of better quality, allowing the viewing of deeper tissue for the specimen as well as reducing the brightness artifact. The construction of surface coils for viewing specific tissues or anatomical regions improves image quality. The next step in this ongoing project will be the application of these concepts to units designed for use in humans. (Author) 14 refs

  15. Reducing high Reynolds number hydroacoustic noise using superhydrophobic coating

    International Nuclear Information System (INIS)

    Elboth, Thomas; Reif, Bjørn Anders Pettersson; Andreassen, Øyvind; Martell, Michael B

    2011-01-01

    The objective of this study is to assess and quantify the effect of a superhydrophobic surface coating on turbulence-generated flow noise. The study utilizes results obtained from high Reynolds-number full-scale flow noise measurements taken on a commercial seismic streamer and results from low Reynolds-number direct numerical simulations. It is shown that it is possible to significantly reduce both the frictional drag and the levels of the turbulence generated flow noise even at very high Reynolds-numbers. For instance, frequencies below 10 Hz a reduction in the flow noise level of nearly 50% was measured. These results can be attributed to a reduced level of shear stress and change in the kinematic structure of the turbulence, both of which occur in the immediate vicinity of the superhydrophobic surface.

  16. Effects of halogens on interactions between a reduced TiO{sub 2} (110) surface and noble metal atoms: A DFT study

    Energy Technology Data Exchange (ETDEWEB)

    Tada, Kohei, E-mail: k-tada@aist.go.jp [Department of Chemistry, Graduate School of Science, Osaka University, 1-1, Machikaneyama, Toyonaka, Osaka, 560-0043 (Japan); Research Institute of Electrochemical Energy, National Institute of Advanced Industrial Science and Technology (AIST), 1-8-31, Midorigaoka, Ikeda, Osaka, 563-8577 (Japan); Koga, Hiroaki [Element Strategy Initiative for Catalysts and Batteries (ESICB), Kyoto University, 1-30 Goryo Ohara, Nishikyo, Kyoto, 615-8245 (Japan); Hayashi, Akihide; Kondo, Yudai; Kawakami, Takashi; Yamanaka, Shusuke [Department of Chemistry, Graduate School of Science, Osaka University, 1-1, Machikaneyama, Toyonaka, Osaka, 560-0043 (Japan); Okumura, Mitsutaka [Department of Chemistry, Graduate School of Science, Osaka University, 1-1, Machikaneyama, Toyonaka, Osaka, 560-0043 (Japan); Element Strategy Initiative for Catalysts and Batteries (ESICB), Kyoto University, 1-30 Goryo Ohara, Nishikyo, Kyoto, 615-8245 (Japan)

    2017-07-31

    Highlights: • We investigated the halogen effect on the interactions of noble metals with TiO{sub 2}. • Halogen atoms inhibit electron transfer from TiO{sub 2} to noble metals. • Iodine stabilizes the adsorption of noble metals especially for Ag and Cu. • Electron transfer from the TiO{sub 2} is effective in anchoring Au and Pt atoms. • Covalent interaction with the support is effective in anchoring Ag and Cu atoms. - Abstract: Using DFT calculation, we investigate the effects of halogens on the interactions between rutile TiO{sub 2} (110) and noble metal atoms (Au, Ag, Cu, Pt, and Pd). Fluorine, chlorine, and bromine atoms occupy the oxygen defect sites of TiO{sub 2}, decreasing the stability of noble metal atoms on the surface. This decrease occurs because the halogens inhibit electron transfer from TiO{sub 2} to the noble metal atoms; the electron transfer from reduced TiO{sub 2} to the noble metal atom stabilizes the noble metal atom adsorption. In contrast, iodine strengthens the interactions between TiO{sub 2} and some noble metal atoms, namely Ag and Cu. This stabilization occurs because of the covalent interaction between iodine-doped TiO{sub 2} and the noble metal atom. Therefore, the stabilization is explained well by chemical hardness. This result suggests that iodine-doping of a TiO{sub 2} surface would be an effective method for the preparation of highly stabilized noble metal clusters.

  17. Rapid Surface Oxidation as a Source of Surface Degradation Factor for Bi 2 Se 3

    KAUST Repository

    Kong, Desheng

    2011-06-28

    Bismuth selenide (Bi2Se3) is a topological insulator with metallic surface states (SS) residing in a large bulk bandgap. In experiments, synthesized Bi2Se3 is often heavily n-type doped due to selenium vacancies. Furthermore, it is discovered from experiments on bulk single crystals that Bi2Se3 gets additional n-type doping after exposure to the atmosphere, thereby reducing the relative contribution of SS in total conductivity. In this article, transport measurements on Bi2Se3 nanoribbons provide additional evidence of such environmental doping process. Systematic surface composition analyses by X-ray photoelectron spectroscopy reveal fast formation and continuous growth of native oxide on Bi2Se3 under ambient conditions. In addition to n-type doping at the surface, such surface oxidation is likely the material origin of the degradation of topological SS. Appropriate surface passivation or encapsulation may be required to probe topological SS of Bi2Se3 by transport measurements. © 2011 American Chemical Society.

  18. Adsorption of surface functionalized silica nanoparticles onto mineral surfaces and decane/water interface

    International Nuclear Information System (INIS)

    Metin, Cigdem O.; Baran, Jimmie R.; Nguyen, Quoc P.

    2012-01-01

    The adsorption of silica nanoparticles onto representative mineral surfaces and at the decane/water interface was studied. The effects of particle size (the mean diameters from 5 to 75 nm), concentration and surface type on the adsorption were studied in detail. Silica nanoparticles with four different surfaces [unmodified, surface modified with anionic (sulfonate), cationic (quaternary ammonium (quat)) or nonionic (polyethylene glycol (PEG)) surfactant] were used. The zeta potential of these silica nanoparticles ranges from −79.8 to 15.3 mV. The shape of silica particles examined by a Hitachi-S5500 scanning transmission electron microscope (STEM) is quite spherical. The adsorption of all the nanoparticles (unmodified or surface modified) on quartz and calcite surfaces was found to be insignificant. We used interfacial tension (IFT) measurements to investigate the adsorption of silica nanoparticles at the decane/water interface. Unmodified nanoparticles or surface modified ones with sulfonate or quat do not significantly affect the IFT of the decane/water interface. It also does not appear that the particle size or concentration influences the IFT. However, the presence of PEG as a surface modifying material significantly reduces the IFT. The PEG surface modifier alone in an aqueous solution, without the nanoparticles, yields the same IFT reduction for an equivalent PEG concentration as that used for modifying the surface of nanoparticles. Contact angle measurements of a decane droplet on quartz or calcite plate immersed in water (or aqueous nanoparticle dispersion) showed a slight change in the contact angle in the presence of the studied nanoparticles. The results of contact angle measurements are in good agreement with experiments of adsorption of nanoparticles on mineral surfaces or decane/water interface. This study brings new insights into the understanding and modeling of the adsorption of surface-modified silica nanoparticles onto mineral surfaces and

  19. Atomic structure of the SnO2 (110) surface

    International Nuclear Information System (INIS)

    Godin, T.J.; LaFemina, J.P.

    1991-12-01

    Using a tight-binding, total-energy model, we examine atomic relaxations of the ideal stoichiometric and reduced tin oxide (11) surfaces. In both cases we find a nearly bond-length conserving rumple of the top layer, and a smaller counter-relaxation of the second layer. These calculations show no evidence of surface states in the band gap for either surface

  20. Characterization of the surfaceome of the metal-reducing bacterium Desulfotomaculum reducens

    Directory of Open Access Journals (Sweden)

    Elena eDalla Vecchia

    2014-08-01

    Full Text Available Desulfotomaculum reducens strain MI-1 is a Gram-positive, sulfate-reducing bacterium also capable of reducing Fe(III. Metal reduction in Gram-positive bacteria is poorly understood. Here, we investigated Fe(III reduction with lactate, a non-fermentable substrate, as the electron donor. Lactate consumption is concomitant to Fe(III reduction, but does not support significant growth, suggesting that little energy can be conserved from this process and that it may occur fortuitously. D. reducens can reduce both soluble (Fe(III-citrate and insoluble (hydrous ferric oxide, HFO Fe(III. Because physically inaccessible HFO was not reduced, we concluded that reduction requires direct contact under these experimental conditions. This implies the presence of a surface exposed reductase capable of transferring electrons from the cell to the extracellular electron acceptor. With the goal of characterizing the role of surface proteins in D. reducens and of identifying candidate Fe(III reductases, we carried out an investigation of the surface proteome (surfaceome of D. reducens. Cell surface exposed proteins were extracted by trypsin cell shaving or by lysozyme treatment, and analyzed by liquid chromatography-tandem mass spectrometry. This investigation revealed that the surfaceome fulfills many functions, including solute transport, protein export, maturation and hydrolysis, peptidoglycan synthesis and modification, and chemotaxis. Furthermore, a few redox-active proteins were identified. Among these, three are putatively involved in Fe(III reduction, i.e., a membrane-bound hydrogenase 4Fe-4S cluster subunit (Dred_0462, a heterodisulfide reductase subunit A (Dred_0143 and a protein annotated as alkyl hydroperoxide reductase but likely functioning as a thiol-disulfide oxidoreductase (Dred_1533.

  1. Remote surface testing and inspection vehicle

    International Nuclear Information System (INIS)

    Hyde, E.A.; Goldsmith, H.A.; Proudlove, M.J.

    1981-01-01

    A remotely controlled vehicle capable of roving over the outer surface of a nuclear reactor primary vessel carrying inspection instrumentation. The vehicle comprises an elongate bridge having a pair of suction support pads. Each pad carries gas thrusters for acting in opposition to the suction effort thereby to reduce adherence of the pads and enable displacement of the vehicle over the surface. The vehicle is supported by a services conducting umbilical. (author)

  2. Identification of Surface Exposed Elementary Body Antigens of ...

    African Journals Online (AJOL)

    This study sought to identify the surface exposed antigenic components of Cowdria ruminantium elementary body (EB) by biotin labeling, determine effect of reducing and non-reducing conditions and heat on the mobility of these antigens and their reactivity to antibodies from immunized animals by Western blotting.

  3. 4H-SiC surface energy tuning by nitrogen up-take

    Energy Technology Data Exchange (ETDEWEB)

    Pitthan, E., E-mail: eduardo.pitthan@ufrgs.br [Institute for Advanced Materials, Devices and Nanotechnology, Rutgers University, Piscataway, NJ 08854 (United States); PGMICRO, UFRGS, 91509-900, Porto Alegre, RS (Brazil); Amarasinghe, V.P. [Institute for Advanced Materials, Devices and Nanotechnology, Rutgers University, Piscataway, NJ 08854 (United States); Xu, C.; Gustafsson, T. [Institute for Advanced Materials, Devices and Nanotechnology, Rutgers University, Piscataway, NJ 08854 (United States); Department of Physics and Astronomy, Rutgers University, Piscataway, NJ 08854 (United States); Stedile, F.C. [PGMICRO, UFRGS, 91509-900, Porto Alegre, RS (Brazil); Instituto de Química, UFRGS, 91509-900, Porto Alegre, RS (Brazil); Feldman, L.C. [Institute for Advanced Materials, Devices and Nanotechnology, Rutgers University, Piscataway, NJ 08854 (United States); Department of Physics and Astronomy, Rutgers University, Piscataway, NJ 08854 (United States)

    2017-04-30

    Highlights: • Wettability modification of 4H-SiC as a function of nitrogen adsorption is reported. • SiC surface energy was significantly reduced as nitrogen was incorporated. • Modifications obtained were proved to be inert to etching and stable against time. • Variable control of SiC surface provides new opportunities for biomedical applications. - Abstract: Surface energy modification and surface wettability of 4H silicon carbide (0001) as a function of nitrogen adsorption is reported. The surface wettability is shown to go from primarily hydrophilic to hydrophobic and the surface energy was significantly reduced with increasing nitrogen incorporation. These changes are investigated by x-ray photoelectron spectroscopy and contact angle measurements. The surface energy was quantitatively determined by the Fowkes model and interpreted primarily in terms of the variation of the surface chemistry with nitrogen coverage. Variable control of SiC surface energies with a simple and controllable atomic additive such as nitrogen that is inert to etching, stable against time, and also effective in electrical passivation, can provide new opportunities for SiC biomedical applications, where surface wetting plays an important role in the interaction with the biological interfaces.

  4. Surface treated fly ash filled modified epoxy composites

    Directory of Open Access Journals (Sweden)

    Uma Dharmalingam

    2015-01-01

    Full Text Available Abstract Fly ash, an inorganic alumino silicate has been used as filler in epoxy matrix, but it reduces the mechanical properties due to its poor dispersion and interfacial bonding with the epoxy matrix. To improve its interfacial bonding with epoxy matrix, surface treatment of fly ash was done using surfactant sodium lauryl sulfate and silane coupling agent glycidoxy propyl trimethoxy silane. An attempt is also made to reduce the particle size of fly ash using high pressure pulverizer. To improve fly ash dispersion in epoxy matrix, the epoxy was modified by mixing with amine containing liquid silicone rubber (ACS. The effect of surface treated fly ash with varying filler loadings from 10 to 40% weight on the mechanical, morphological and thermal properties of modified epoxy composites was investigated. The surface treated fly ash was characterized by particle size analyzer and FTIR spectra. Morphological studies of surface treated fly ash filled modified epoxy composites indicate good dispersion of fillers in the modified epoxy matrix and improves its mechanical properties. Impact strength of the surface treated fly ash filled modified epoxy composites show more improvement than unmodified composites.

  5. Low-cycle fatigue of sheet elements with ''soft'' surface layer

    International Nuclear Information System (INIS)

    Luk'yanov, V.F.; Kharchenko, V.Ya.; Berezutskij, V.I.; Ovsyannikov, V.G.

    1978-01-01

    Investigated are regularities of low-cycle fatigue of bimetallic sheet constructions made of chrome-nickel-molybdenum steel, plated with a low-alloyed steel with a reduced yield limit. Static repeated bending tests have been carried out using two-layer samples. The surface layer has been shown to increase resistance to nucleation and propagation of cracks under pulsating load if stresses are not more than 2 times higher than the yield limit. Increase in stresses leads to elastoplastic deformation and reduces durability. The positive effect of the surface layer is advisable to be used when welding-up surface defects and strengthening welded joints of high-strength steels

  6. Bacterial resistance of self-assembled surfaces using PPOm-b-PSBMAn zwitterionic copolymer - concomitant effects of surface topography and surface chemistry on attachment of live bacteria.

    Science.gov (United States)

    Hsiao, Sheng-Wen; Venault, Antoine; Yang, Hui-Shan; Chang, Yung

    2014-06-01

    Three well-defined diblock copolymers made of poly(sulfobetaine methacrylate) (poly(SBMA)) and poly(propylene oxide) (PPO) groups were synthesized by atom transfer radical polymerization (ATRP) method. They were physically adsorbed onto three types of surfaces having different topography, including smooth flat surface, convex surface, and indented surface. Chemical state of surfaces was characterized by XPS while the various topographies were examined by SEM and AFM. Hydrophilicity of surfaces was dependent on both the surface chemistry and the surface topography, suggesting that orientation of copolymer brushes can be tuned in the design of surfaces aimed at resisting bacterial attachment. Escherichia coli, Staphylococcus epidermidis, Streptococcus mutans and Escherichia coli with green fluorescent protein (E. coli GFP) were used in bacterial tests to assess the resistance to bacterial attachment of poly(SBMA)-covered surfaces. Results highlighted a drastic improvement of resistance to bacterial adhesion with the increasing of poly(SBMA) to PPO ratio, as well as an important effect of surface topography. The chemical effect was directly related to the length of the hydrophilic moieties. When longer, more water could be entrapped, leading to improved anti-bacterial properties. The physical effect impacted on the orientation of the copolymer brushes, as well as on the surface contact area available. Convex surfaces as well as indented surfaces wafer presented the best resistance to bacterial adhesion. Indeed, bacterial attachment was more importantly reduced on these surfaces compared with smooth surfaces. It was explained by the non-orthogonal orientation of copolymer brushes, resulting in a more efficient surface coverage of zwitterionic molecules. This work suggests that not only the control of surface chemistry is essential in the preparation of surfaces resisting bacterial attachment, but also the control of surface topography and orientation of antifouling

  7. Walking on a moving surface: energy-optimal walking motions on a shaky bridge and a shaking treadmill can reduce energy costs below normal.

    Science.gov (United States)

    Joshi, Varun; Srinivasan, Manoj

    2015-02-08

    Understanding how humans walk on a surface that can move might provide insights into, for instance, whether walking humans prioritize energy use or stability. Here, motivated by the famous human-driven oscillations observed in the London Millennium Bridge, we introduce a minimal mathematical model of a biped, walking on a platform (bridge or treadmill) capable of lateral movement. This biped model consists of a point-mass upper body with legs that can exert force and perform mechanical work on the upper body. Using numerical optimization, we obtain energy-optimal walking motions for this biped, deriving the periodic body and platform motions that minimize a simple metabolic energy cost. When the platform has an externally imposed sinusoidal displacement of appropriate frequency and amplitude, we predict that body motion entrained to platform motion consumes less energy than walking on a fixed surface. When the platform has finite inertia, a mass- spring-damper with similar parameters to the Millennium Bridge, we show that the optimal biped walking motion sustains a large lateral platform oscillation when sufficiently many people walk on the bridge. Here, the biped model reduces walking metabolic cost by storing and recovering energy from the platform, demonstrating energy benefits for two features observed for walking on the Millennium Bridge: crowd synchrony and large lateral oscillations.

  8. Surface characterization of the cement for retention of implant supported dental prostheses: In vitro evaluation of cement roughness and surface free energy

    Energy Technology Data Exchange (ETDEWEB)

    Brajkovic, Denis [Clinic for Dentistry, Department of Maxillofacial Surgery, Faculty of Medical Sciences, University of Kragujevac, Svetozara Markovica 69, 34000 Kragujevac (Serbia); Antonijevic, Djordje; Milovanovic, Petar [Laboratory for Anthropology, Institute of Anatomy, School of Medicine, University of Belgrade, Dr. Subotica 4/2, 11000 Belgrade (Serbia); Kisic, Danilo [Laboratory for Atomic Physics, Institute of Nuclear Sciences “Vinca”, University of Belgrade, Belgrade (Serbia); Zelic, Ksenija; Djuric, Marija [Laboratory for Anthropology, Institute of Anatomy, School of Medicine, University of Belgrade, Dr. Subotica 4/2, 11000 Belgrade (Serbia); Rakocevic, Zlatko, E-mail: zlatkora@vinca.rs [Laboratory for Atomic Physics, Institute of Nuclear Sciences “Vinca”, University of Belgrade, Belgrade (Serbia)

    2014-08-30

    Graphical abstract: - Highlights: • Surface free energy and surface roughness influence bacterial adhesion. • Bacterial colonization causes periimplantitis and implant loss. • Zinc-based, glass-ionomers and resin-cements were investigated. • Glass-ionomers-cements present the lowest values of surface free energy and roughness. • Glass-ionomer-cements surface properties result with reduced bacterial adhesion. - Abstract: Background: Material surface free energy and surface roughness strongly influence the bacterial adhesion in oral cavity. The aim of this study was to analyze these two parameters in various commercial luting agents used for cementation of implant restorations. Materials and methods: Zinc-based, glass-ionomers, resin modified glass-ionomer and resin-cements were investigated. Contact angle and surface free energy were measured by contact angle analyzer using Image J software program. Materials’ average roughness and fractal dimension were calculated based on Atomic Force Microscope topography images. Results: Zinc phosphate cements presented significantly higher total surface free energy and significantly lower dispersive component of surface free energy compared to other groups, while resin-cements showed significantly lower polar component than other groups. The surface roughness and fractal dimension values were statistically the highest in the zinc phosphate cements and the lowest for the glass-ionomers cements. Conclusion: Glass-ionomers-cements presented lower values of surface free energy and surface roughness than zinc phosphate and resin cements, indicating that their surfaces are less prone to biofilm adhesion. Practical implications: Within limitations of an in vitro trial, our results indicate that glass-ionomers-cements could be the cements of choice for fixation of cement retained implant restorations due to superior surface properties compared to zinc phosphate and resin cements, which may result in reduced plaque formation

  9. Surface characterization of the cement for retention of implant supported dental prostheses: In vitro evaluation of cement roughness and surface free energy

    International Nuclear Information System (INIS)

    Brajkovic, Denis; Antonijevic, Djordje; Milovanovic, Petar; Kisic, Danilo; Zelic, Ksenija; Djuric, Marija; Rakocevic, Zlatko

    2014-01-01

    Graphical abstract: - Highlights: • Surface free energy and surface roughness influence bacterial adhesion. • Bacterial colonization causes periimplantitis and implant loss. • Zinc-based, glass-ionomers and resin-cements were investigated. • Glass-ionomers-cements present the lowest values of surface free energy and roughness. • Glass-ionomer-cements surface properties result with reduced bacterial adhesion. - Abstract: Background: Material surface free energy and surface roughness strongly influence the bacterial adhesion in oral cavity. The aim of this study was to analyze these two parameters in various commercial luting agents used for cementation of implant restorations. Materials and methods: Zinc-based, glass-ionomers, resin modified glass-ionomer and resin-cements were investigated. Contact angle and surface free energy were measured by contact angle analyzer using Image J software program. Materials’ average roughness and fractal dimension were calculated based on Atomic Force Microscope topography images. Results: Zinc phosphate cements presented significantly higher total surface free energy and significantly lower dispersive component of surface free energy compared to other groups, while resin-cements showed significantly lower polar component than other groups. The surface roughness and fractal dimension values were statistically the highest in the zinc phosphate cements and the lowest for the glass-ionomers cements. Conclusion: Glass-ionomers-cements presented lower values of surface free energy and surface roughness than zinc phosphate and resin cements, indicating that their surfaces are less prone to biofilm adhesion. Practical implications: Within limitations of an in vitro trial, our results indicate that glass-ionomers-cements could be the cements of choice for fixation of cement retained implant restorations due to superior surface properties compared to zinc phosphate and resin cements, which may result in reduced plaque formation

  10. Iron cycling at corroding carbon steel surfaces

    Science.gov (United States)

    Lee, Jason S.; McBeth, Joyce M.; Ray, Richard I.; Little, Brenda J.; Emerson, David

    2013-01-01

    Surfaces of carbon steel (CS) exposed to mixed cultures of iron-oxidizing bacteria (FeOB) and dissimilatory iron-reducing bacteria (FeRB) in seawater media under aerobic conditions were rougher than surfaces of CS exposed to pure cultures of either type of microorganism. The roughened surface, demonstrated by profilometry, is an indication of loss of metal from the surface. In the presence of CS, aerobically grown FeOB produced tight, twisted helical stalks encrusted with iron oxides. When CS was exposed anaerobically in the presence of FeRB, some surface oxides were removed. However, when the same FeOB and FeRB were grown together in an aerobic medium, FeOB stalks were less encrusted with iron oxides and appeared less tightly coiled. These observations suggest that iron oxides on the stalks were reduced and solubilized by the FeRB. Roughened surfaces of CS and denuded stalks were replicated with three culture combinations of different species of FeOB and FeRB under three experimental conditions. Measurements of electrochemical polarization resistance established different rates of corrosion of CS in aerobic and anaerobic media, but could not differentiate rate differences between sterile controls and inoculated exposures for a given bulk concentration of dissolved oxygen. Similarly, total iron in the electrolyte could not be used to differentiate treatments. The experiments demonstrate the potential for iron cycling (oxidation and reduction) on corroding CS in aerobic seawater media. PMID:24093730

  11. The use of Powdered Activated Carbon in reducing the Doc in water treatment plants

    International Nuclear Information System (INIS)

    Nikravesh, S. H.; Etemad-Shahidi, A.; Razeghi, N.

    2003-01-01

    Today as the technology improves and the application of energy and chemicals enhances, the organic pollutants increases in surface waters in which waste waters are discharged into. In order to reduce water-born diseases, necessary actions should be taken to decrease the pollutants. Common methods of surface water treatment are not sufficient anymore. Therefore complementary methods like using activated carbon, aeration, oxidation and reverse osmosis should be used. In this paper the use of powdered activated carbon, Total organic carbon test and jar test in reducing the concentration of organic carbons in water treatment is investigated. Initial experimental results showed large errors in total organic carbon evaluation so dissolved organic carbon was measured instead. The results showed that using the powdered activated carbon in addition to conventional treatment method using ferric chloride, greatly reduces organic pollutants. Adding about 60 mg/lit of powdered activated carbon may reduce dissolved organic carbon up to 90% in optimum conditions. However, different factors like the quality of surface water, experimental errors, instrumental errors and tool errors can influence the experimental results

  12. Growth morphologies of crystal surfaces

    Science.gov (United States)

    Xiao, Rong-Fu; Alexander, J. Iwan D.; Rosenberger, Franz

    1991-03-01

    We have expanded our earlier Monte Carlo model [Phys. Rev. A 38, 2447 (1988); J. Crystal Growth 100, 313 (1990)] to three dimensions and included reevaporation after accommodation and growth on dislocation-induced steps. We found again that, for a given set of growth parameters, the critical size, beyond which a crystal cannot retain its macroscopically faceted shape, scales linearly with the mean free path in the vapor. However, the three-dimensional (3D) the systems show increased shape stability compared to corresponding 2D cases. Extrapolation of the model results to mean-free-path conditions used in morphological stability experiments leads to order-of-magnitude agreement of the predicted critical size with experimental findings. The stability region for macroscopically smooth (faceted) surfaces in the parameter space of temperature and supersaturation depends on both the surface and bulk diffusion. While surface diffusion is seen to smooth the growth morphology on the scale of the surface diffusion length, bulk diffusion is always destabilizing. The atomic surface roughness increases with increase in growth temperature and supersaturation. That is, the tendency of surface kinetics anisotropies to stabilize the growth shape is reduced through thermal and kinetic roughening. It is also found that the solid-on-solid assumption, which can be advantageously used at low temperatures and supersaturations, is insufficient to describe the growth dynamics of atomically rough interfaces where bulk diffusion governs the process. For surfaces with an emerging screw dislocation, we find that the spiral growth mechanism dominates at low temperatures and supersaturations. The polygonization of a growth spiral decreases with increasing temperature or supersaturation. When the mean free path in the nutrient is comparable to the lattice constant, the combined effect of bulk and surface diffusion reduces the terrace width of a growth spiral in its center region. At elevated

  13. Desulfovibrio zosterae sp. nov., a new sulfate reducer isolated from surface-sterilized roots of the seagrass Zostera marina.

    Science.gov (United States)

    Nielsen, J T; Liesack, W; Finster, K

    1999-04-01

    A sulfate-reducing bacterium, designated strain lacT, was isolated from surface-sterilized roots of the benthic macrophyte Zostera marina. Cells were motile by means of a single polar flagellum. Strain lacT utilized lactate, pyruvate, malate, ethanol, L-alanine, fumarate, choline and fructose with sulfate as electron acceptor. In addition, fumarate, pyruvate and fructose were also degraded without an external electron acceptor. Sulfate could be substituted with thiosulfate, sulfite and elemental sulfur. Optimal growth was observed between 32.5 and 34.5 degrees C, at an NaCl concentration of 0.2 M and in a pH range between 6.8 and 7.3. The G + C content of the DNA was 42.7 +/- 0.2 mol%. Desulfoviridin and catalase were present. Strain lacT contained c-type cytochromes. Comparative 16S rRNA gene sequence analysis and the fatty acid pattern grouped this isolate into the genus Desulfovibrio. However, strain lacT differs from all other described Desulfovibrio species on the bases of its 16S rRNA gene sequence, the G + C content, its cellular lipid pattern and the utilization pattern of substrates. These characteristics establish strain lacT (= DSM 11974T) as a novel species of the genus Desulfovibrio, for which the name Desulfovibrio zosterae sp. nov. is proposed.

  14. Functional levels of floor surface roughness for the prevention of slips and falls: clean-and-dry and soapsuds-covered wet surfaces.

    Science.gov (United States)

    Kim, In-Ju; Hsiao, Hongwei; Simeonov, Peter

    2013-01-01

    Literature has shown a general trend that slip resistance performance improves with floor surface roughness. However, whether slip resistance properties are linearly correlated with surface topographies of the floors or what roughness levels are required for effective slip resistance performance still remain to be answered. This pilot study aimed to investigate slip resistance properties and identify functional levels of floor surface roughness for practical design applications in reducing the risk of slip and fall incidents. A theory model was proposed to characterize functional levels of surface roughness of floor surfaces by introducing a new concept of three distinctive zones. A series of dynamic friction tests were conducted using 3 shoes and 9 floor specimens under clean-and-dry as well as soapsuds-covered slippery wet environments. The results showed that all the tested floor-shoe combinations provided sufficient slip resistances performance under the clean-and-dry condition. A significant effect of floor type (surface roughness) on dynamic friction coefficient (DFC) was found in the soapsuds-covered wet condition. As compared to the surface roughness effects, the shoe-type effects were relatively small. Under the soapsuds-covered wet condition, floors with 50 μm in Ra roughness scale seemed to represent an upper bound in the functional range of floor surface roughness for slip resistance because further increase of surface roughness provided no additional benefit. A lower bound of the functional range for slip resistance under the soapsuds-covered wet condition was estimated from the requirement of DFC > 0.4 at Ra ≅ 17 μm. Findings from this study may have potential safety implications in the floor surface design for reducing slip and fall hazards. Published by Elsevier Ltd.

  15. Reduced cost and improved figure of sapphire optical components

    Science.gov (United States)

    Walters, Mark; Bartlett, Kevin; Brophy, Matthew R.; DeGroote Nelson, Jessica; Medicus, Kate

    2015-10-01

    Sapphire presents many challenges to optical manufacturers due to its high hardness and anisotropic properties. Long lead times and high prices are the typical result of such challenges. The cost of even a simple 'grind and shine' process can be prohibitive. The high precision surfaces required by optical sensor applications further exacerbate the challenge of processing sapphire thereby increasing cost further. Optimax has demonstrated a production process for such windows that delivers over 50% time reduction as compared to traditional manufacturing processes for sapphire, while producing windows with less than 1/5 wave rms figure error. Optimax's sapphire production process achieves significant improvement in cost by implementation of a controlled grinding process to present the best possible surface to the polishing equipment. Following the grinding process is a polishing process taking advantage of chemical interactions between slurry and substrate to deliver excellent removal rates and surface finish. Through experiments, the mechanics of the polishing process were also optimized to produce excellent optical figure. In addition to reducing the cost of producing large sapphire sensor windows, the grinding and polishing technology Optimax has developed aids in producing spherical sapphire components to better figure quality. In addition to reducing the cost of producing large sapphire sensor windows, the grinding and polishing technology Optimax has developed aids in producing spherical sapphire components to better figure quality. Through specially developed polishing slurries, the peak-to-valley figure error of spherical sapphire parts is reduced by over 80%.

  16. Solid oxide fuel cell cathode with oxygen-reducing layer

    Science.gov (United States)

    Surdoval, Wayne A.; Berry, David A.; Shultz, Travis

    2018-04-03

    The disclosure provides a SOFC comprised of an electrolyte, anode, and cathode, where the cathode comprises an MIEC and an oxygen-reducing layer. The oxygen-reducing layer is in contact with the MIEC, and the MIEC is generally between and separating the oxygen-reducing layer and the electrolyte. The oxygen-reducing layer is comprised of single element oxides, single element carbonates, or mixtures thereof, and has a thickness of less than about 30 nm. In a particular embodiment, the thickness is less than 5 nm. In another embodiment, the thickness is about 3 monolayers or less. The oxygen-reducing layer may be a continuous film or a discontinuous film with various coverage ratios. The oxygen-reducing layer at the thicknesses described may be generated on the MIEC surface using means known in the art such as, for example, ALD processes.

  17. Frictional Performance Assessment of Cemented Carbide Surfaces Textured by Laser

    Science.gov (United States)

    Fang, S.; Llanes, L.; Klein, S.; Gachot, C.; Rosenkranz, A.; Bähre, D.; Mücklich, F.

    2017-10-01

    Cemented carbides are advanced engineering materials often used in industry for manufacturing cutting tools or supporting parts in tribological system. In order to improve service life, special attention has been paid to change surface conditions by means of different methods, since surface modification can be beneficial to reduce the friction between the contact surfaces as well as to avoid unintended damage. Laser surface texturing is one of the newly developed surface modification methods. It has been successfully introduced to fabricate some basic patterns on cemented carbide surfaces. In this work, Direct Laser Interference Patterning Technique (DLIP) is implemented to produce special line-like patterns on a cobalt (Co) and nickel (Ni) based cemented tungsten carbide grade. It is proven that the laser-produced patterns have high geometrical precision and quality stability. Furthermore, tribology testing using a nano-tribometer unit shows that friction is reduced by the line-like patterns, as compared to the polished one, under both lubricated and dry testing regimes, and the reduction is more pronounced in the latter case.

  18. Spatially-varying surface roughness and ground-level air quality in an operational dispersion model

    International Nuclear Information System (INIS)

    Barnes, M.J.; Brade, T.K.; MacKenzie, A.R.; Whyatt, J.D.; Carruthers, D.J.; Stocker, J.; Cai, X.; Hewitt, C.N.

    2014-01-01

    Urban form controls the overall aerodynamic roughness of a city, and hence plays a significant role in how air flow interacts with the urban landscape. This paper reports improved model performance resulting from the introduction of variable surface roughness in the operational air-quality model ADMS-Urban (v3.1). We then assess to what extent pollutant concentrations can be reduced solely through local reductions in roughness. The model results suggest that reducing surface roughness in a city centre can increase ground-level pollutant concentrations, both locally in the area of reduced roughness and downwind of that area. The unexpected simulation of increased ground-level pollutant concentrations implies that this type of modelling should be used with caution for urban planning and design studies looking at ventilation of pollution. We expect the results from this study to be relevant for all atmospheric dispersion models with urban-surface parameterisations based on roughness. -- Highlights: • Spatially variable roughness improved performance of an operational model. • Scenario modelling explored effect of reduced roughness on air pollution. • Reducing surface roughness can increase modelled ground-level pollution. • Damped vertical mixing outweighs increased horizontal advection in model study. • Result should hold for any model with a land-surface coupling based on roughness. -- Spatially varying roughness improves model simulations of urban air pollutant dispersion. Reducing roughness does not always decrease ground-level pollution concentrations

  19. Fabrication of surface micro- and nanostructures for superhydrophobic surfaces in electric and electronic applications

    Science.gov (United States)

    Xiu, Yonghao

    our understanding of the roughness effect on superhydrophobicity (both contact angle and hysteresis), structured surfaces from polybutadiene, polyurethane, silica, and Si etc. were successfully prepared. For engineering applications of superhydrophobic surfaces, stability issues regarding UV, mechanical robustness and humid environment need to be investigated. Among these factors, UV stability is the first one to be studied. However, most polymer surfaces we prepared failed the purpose. Silica surfaces with excellent UV stability were prepared. This method consists of preparation of rough silica surfaces, thermal treatment and the following surface hydrophobization by fluoroalkyl silane treatment. Fluoroalkyl groups are UV stable and the underlying species are silica which is also UV stable (UV transparent). UV stability on the surface currently is 5,500 h according the standard test method of ASTM D 4329. No degradation on surface superhydrophobicity was observed. New methods for preparing superhydrophobic and transparent silica surfaces were investigated using urea-choline chloride eutectic liquid to generate fine roughness and reduce the cost for preparation of surface structures. Another possible application for self-cleaning in photovoltaic panels was investigated on Si surfaces by construction of the two-scale rough structures followed by fluoroalkyl silane treatment. Metal (Au) assisted etching was employed to fabricate nanostructures on micrometer pyramid surfaces. The light reflection on the prepared surfaces was investigated. After surface texturing using KOH etching for micrometer pyramids and the following nanostructure using metal assisted etching, surface light reflection reduced to a minimum value which shows that this surface texturing technique is highly promising for improving the photovoltaic efficiency while imparting photovoltaics the self-cleaning feature. This surface is also expected to be UV stable due to the same fluoroalkyl silane used

  20. Are vacuum-filtrated reduced graphene oxide membranes symmetric?

    KAUST Repository

    Tang, Bo; Zhang, Lianbin; Li, Renyuan; Wu, Jinbo; Hedhili, Mohamed Neijib; Wang, Peng

    2015-01-01

    Graphene or reduced graphene oxide (rGO) membrane-based materials are promising for many advanced applications due to their exceptional properties. One of the most widely used synthesis methods for rGO membranes is vacuum filtration of graphene oxide (GO) on a filter membrane, followed by reduction, which shows great advantages such as operational convenience and good controllability. Despite vacuum-filtrated rGO membranes being widely used in many applications, a fundamental question is overlooked: are the top and bottom surfaces of the membranes formed at the interfaces with air and with the filter membrane respectively symmetric or asymmetric? This work, for the first time, reports the asymmetry of the vacuum-filtrated rGO membranes and discloses the filter membranes’ physical imprint on the bottom surface of the rGO membrane, which takes place when the filter membrane surface pores have similar dimension to GO sheets. This result points out that the asymmetric surface properties should be cautiously taken into consideration while designing the surface-related applications for GO and rGO membranes.

  1. Are vacuum-filtrated reduced graphene oxide membranes symmetric?

    KAUST Repository

    Tang, Bo

    2015-12-02

    Graphene or reduced graphene oxide (rGO) membrane-based materials are promising for many advanced applications due to their exceptional properties. One of the most widely used synthesis methods for rGO membranes is vacuum filtration of graphene oxide (GO) on a filter membrane, followed by reduction, which shows great advantages such as operational convenience and good controllability. Despite vacuum-filtrated rGO membranes being widely used in many applications, a fundamental question is overlooked: are the top and bottom surfaces of the membranes formed at the interfaces with air and with the filter membrane respectively symmetric or asymmetric? This work, for the first time, reports the asymmetry of the vacuum-filtrated rGO membranes and discloses the filter membranes’ physical imprint on the bottom surface of the rGO membrane, which takes place when the filter membrane surface pores have similar dimension to GO sheets. This result points out that the asymmetric surface properties should be cautiously taken into consideration while designing the surface-related applications for GO and rGO membranes.

  2. Single-layer model for surface roughness.

    Science.gov (United States)

    Carniglia, C K; Jensen, D G

    2002-06-01

    Random roughness of an optical surface reduces its specular reflectance and transmittance by the scattering of light. The reduction in reflectance can be modeled by a homogeneous layer on the surface if the refractive index of the layer is intermediate to the indices of the media on either side of the surface. Such a layer predicts an increase in the transmittance of the surface and therefore does not provide a valid model for the effects of scatter on the transmittance. Adding a small amount of absorption to the layer provides a model that predicts a reduction in both reflectance and transmittance. The absorbing layer model agrees with the predictions of a scalar scattering theory for a layer with a thickness that is twice the rms roughness of the surface. The extinction coefficient k for the layer is proportional to the thickness of the layer.

  3. Motor competence and characteristics within the preschool environment.

    Science.gov (United States)

    True, Larissa; Pfeiffer, Karin Allor; Dowda, Marsha; Williams, Harriet G; Brown, William H; O'Neill, Jennifer R; Pate, Russell R

    2017-08-01

    Environmental characteristics within preschools that influence children's motor competence are largely unknown. The purpose of the present study was to examine the contribution of various preschool environmental characteristics to children's locomotor, object control, and total gross motor scores. Cross-sectional, observational study of 3-5 year-old children (n=229) from 22 preschools in South Carolina. The Children's Activity and Movement in Preschool Study (CHAMPS) Motor Skills Protocol assessed MC. Preschool directors provided information regarding policies and practices. The research team measured playgrounds and classrooms, and the Early Childhood Environment Rating Scale-Revised assessed preschool quality. Time spent in open space and electronic media use were also assessed using direct observation. The aforementioned variables predicted children's object control, locomotor, and total gross motor scores. Classroom size/child ratio, teacher education, playground size, electronic media use, and trips to outside organizations emerged as significant predictors of locomotor score and total motor score. The object control model was non-significant. Preschools may be able to promote motor competence by allowing children more time in open spaces, structured activity experiences, and by expanding existing outdoor playground space whenever possible. Copyright © 2017 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.

  4. Detection of hazardous cavities with combined geophysical methods

    Science.gov (United States)

    Hegymegi, Cs.; Nyari, Zs.; Pattantyus-Abraham, M.

    2003-04-01

    Unknown near-surface cavities often cause problems for municipal communities all over the world. This is the situation in Hungary in many towns and villages, too. Inhabitants and owners of real estates (houses, cottages, lands) are responsible for the safety and stability of their properties. The safety of public sites belongs to the local municipal community. Both (the owner and the community) are interested in preventing accidents. Near-surface cavities (unknown caves or earlier built and forgotten cellars) usually can be easily detected by surface geophysical methods. Traditional and recently developed measuring techniques in seismics, geoelectrics and georadar are suitable for economical investigation of hazardous, potentially collapsing cavities, prior to excavation and reinforcement. This poster will show some example for detection of cellars and caves being dangerous for civil population because of possible collapse under public sites (road, yard, playground, agricultural territory, etc.). The applied and presented methods are ground penetrating radar, seismic surface tomography and analysis of single traces, geoelectric 2D and 3D resistivity profiling. Technology and processing procedure will be presented.

  5. Experimental Method for Measuring Dust Load on Surfaces in Rooms

    DEFF Research Database (Denmark)

    Lengweiler, Philip; Nielsen, Peter V.; Moser, Alfred

    A new experimental setup to investigate the physical process of dust deposition and resuspension on and from surfaces is introduced. Dust deposition can reduce the airborne dust concentration considerably. As a basis for developing methods to eliminate dust-related problems in rooms, there is a n......A new experimental setup to investigate the physical process of dust deposition and resuspension on and from surfaces is introduced. Dust deposition can reduce the airborne dust concentration considerably. As a basis for developing methods to eliminate dust-related problems in rooms......, there is a need for better understanding of the mechanism of dust deposition and resuspension. With the presented experimental setup, the dust load on surfaces in a channel can be measured as a function of the environmental and surface conditions and the type of particles under controlled laboratory conditions....

  6. Field emission and high voltage cleaning of particulate contaminants on extended metallic surfaces

    International Nuclear Information System (INIS)

    Tan, J.; Bonin, B.; Safa, H.

    1996-01-01

    The vacuum insulation properties of extended metallic surfaces depends strongly on their cleanliness. The usual technique to reduce electronic field emission from such surfaces consists in exposing them to very high electric fields during limited periods of time. This kind of processing also reduces the occurrence of vacuum breakdown. The processing of the surface is generally believed to be due to a thermomechanical destruction of the emitting sites, initiated by the emission itself. Comparison of the electric forces vs adherence forces which act on dust particles lying on the surface shows that the processing could also be due simply to the mechanical removal of the dust particles, with a subsequent reduction of field emission from the contaminated surface. (author)

  7. Effect of Artificial Aging Protocols on Surface Gloss of Resin Composites

    Directory of Open Access Journals (Sweden)

    Rafael Santos Rocha

    2017-01-01

    Full Text Available The purpose of this study was to evaluate the effect of aging protocols on surface gloss of composites. Cylindrical resin composite specimens (6 mm in diameter, 1 mm thick were fabricated and divided into three groups (N=60: microfilled (MiFi, nanohybrid (NaHy, and nanofilled (NaFi. Specimens were distributed into four aging subgroups: thermocycling (5° to 55°C, 15,000 cycles; ethanol immersion (15 days; brushing (10,750 cycles; and light aging (216 h. Surface gloss readings (Novo-Curve, Rhopoint TM, England were performed at baseline (R0 and after every one-third of aging protocols (R1 to R3. Data were submitted to one-way repeated measures ANOVA and Tukey’s test (5%. Overall, surface gloss alterations were detected over time (p<0.001. Thermocycling reduced surface gloss, except for NaHy. Ethanol immersion resulted in surface gloss reduction after R1 for MiFi and NaFi, while reduction after R1 and R2 was detected for NaHy. For brushing, gloss reduction was detected after R1 and R3 for all composites. For light aging, gloss was reduced after R1 and R2 for MiFi and NaFi, while a reduction only after R1 was detected for NaHy. The studied aging protocols affect surface gloss differently, being material and aging therapy dependent. In general, the surface gloss is reduced with aging.

  8. Corrugated metal surface with pillars for terahertz surface plasmon polariton waveguide components

    KAUST Repository

    Yuehong, Xu; Yanfeng, Li; Chunxiu, Tian; Jiaguang, Han; Quan, Xu; Xueqian, Zhang; Xixiang, Zhang; Ying, Zhang; Weili, Zhang

    2018-01-01

    In the terahertz regime, due to perfect conductivity of most metals, it is hard to realize a strong confinement of Surface plasmon polaritons (SPPs) although a propagation loss could be sufficiently low. We experimentally demonstrated a structure with periodic pillars arranged on a thin metal surface that supports bound modes of spoof SPPs at terahertz (THz) frequencies. By using scanning near-field THz microscopy, the electric field distribution above the metal surface within a distance of 130 μm was mapped. The results proved that this structure could guide spoof SPPs propagating along subwavelength waveguides, and at the same time reduce field expansion into free space. Further, for the development of integrated optical circuits, several components including straight waveguide, S-bend, Y-splitter and directional couplers were designed and characterized by the same method. We believe that the waveguide components proposed here will pave a new way for the development of flexible, wideband and compact photonic circuits operating at THz frequencies.

  9. Corrugated metal surface with pillars for terahertz surface plasmon polariton waveguide components

    KAUST Repository

    Yuehong, Xu

    2018-01-12

    In the terahertz regime, due to perfect conductivity of most metals, it is hard to realize a strong confinement of Surface plasmon polaritons (SPPs) although a propagation loss could be sufficiently low. We experimentally demonstrated a structure with periodic pillars arranged on a thin metal surface that supports bound modes of spoof SPPs at terahertz (THz) frequencies. By using scanning near-field THz microscopy, the electric field distribution above the metal surface within a distance of 130 μm was mapped. The results proved that this structure could guide spoof SPPs propagating along subwavelength waveguides, and at the same time reduce field expansion into free space. Further, for the development of integrated optical circuits, several components including straight waveguide, S-bend, Y-splitter and directional couplers were designed and characterized by the same method. We believe that the waveguide components proposed here will pave a new way for the development of flexible, wideband and compact photonic circuits operating at THz frequencies.

  10. Electrospray ion source with reduced analyte electrochemistry

    Science.gov (United States)

    Kertesz, Vilmos [Knoxville, TN; Van Berkel, Gary [Clinton, TN

    2011-08-23

    An electrospray ion (ESI) source and method capable of ionizing an analyte molecule without oxidizing or reducing the analyte of interest. The ESI source can include an emitter having a liquid conduit, a working electrode having a liquid contacting surface, a spray tip, a secondary working electrode, and a charge storage coating covering partially or fully the liquid contacting surface of the working electrode. The liquid conduit, the working electrode and the secondary working electrode can be in liquid communication. The electrospray ion source can also include a counter electrode proximate to, but separated from, said spray tip. The electrospray ion source can also include a power system for applying a voltage difference between the working electrodes and a counter-electrode. The power system can deliver pulsed voltage changes to the working electrodes during operation of said electrospray ion source to minimize the surface potential of the charge storage coating.

  11. Wetting characteristics of 3-dimensional nanostructured fractal surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Davis, Ethan, E-mail: ethan.davis4@huskers.unl.edu [Nano & Microsystems Research Laboratory, Department of Mechanical and Materials Engineering, University of Nebraska-Lincoln, W342 Nebraska Hall, Lincoln, NE 68588-0526 (United States); Liu, Ying; Jiang, Lijia; Lu, Yongfeng [Laser Assisted Nano Engineering Lab, Department of Electrical and Computer Engineering, University of Nebraska-Lincoln, 209N Scott Engineering Center, Lincoln, NE 68588-0511 (United States); Ndao, Sidy, E-mail: sndao2@unl.edu [Nano & Microsystems Research Laboratory, Department of Mechanical and Materials Engineering, University of Nebraska-Lincoln, W342 Nebraska Hall, Lincoln, NE 68588-0526 (United States)

    2017-01-15

    Highlights: • Hierarchically structured surfaces were fabricated on the micro/nano-scale. • These structures reduced the contact angle of the inherently hydrophilic material. • Similar surfaces have applications in two-phase heat transfer and microfluidics. - Abstract: This article reports the fabrication and wetting characteristics of 3-dimensional nanostructured fractal surfaces (3DNFS). Three distinct 3DNFS surfaces, namely cubic, Romanesco broccoli, and sphereflake were fabricated using two-photon direct laser writing. Contact angle measurements were performed on the multiscale fractal surfaces to characterize their wetting properties. Average contact angles ranged from 66.8° for the smooth control surface to 0° for one of the fractal surfaces. The change in wetting behavior was attributed to modification of the interfacial surface properties due to the inclusion of 3-dimensional hierarchical fractal nanostructures. However, this behavior does not exactly obey existing surface wetting models in the literature. Potential applications for these types of surfaces in physical and biological sciences are also discussed.

  12. Wetting characteristics of 3-dimensional nanostructured fractal surfaces

    International Nuclear Information System (INIS)

    Davis, Ethan; Liu, Ying; Jiang, Lijia; Lu, Yongfeng; Ndao, Sidy

    2017-01-01

    Highlights: • Hierarchically structured surfaces were fabricated on the micro/nano-scale. • These structures reduced the contact angle of the inherently hydrophilic material. • Similar surfaces have applications in two-phase heat transfer and microfluidics. - Abstract: This article reports the fabrication and wetting characteristics of 3-dimensional nanostructured fractal surfaces (3DNFS). Three distinct 3DNFS surfaces, namely cubic, Romanesco broccoli, and sphereflake were fabricated using two-photon direct laser writing. Contact angle measurements were performed on the multiscale fractal surfaces to characterize their wetting properties. Average contact angles ranged from 66.8° for the smooth control surface to 0° for one of the fractal surfaces. The change in wetting behavior was attributed to modification of the interfacial surface properties due to the inclusion of 3-dimensional hierarchical fractal nanostructures. However, this behavior does not exactly obey existing surface wetting models in the literature. Potential applications for these types of surfaces in physical and biological sciences are also discussed.

  13. SRC Inhibition Reduces NR2B Surface Expression and Synaptic Plasticity in the Amygdala

    Science.gov (United States)

    Sinai, Laleh; Duffy, Steven; Roder, John C.

    2010-01-01

    The Src protein tyrosine kinase plays a central role in the regulation of N-methyl-d-aspartate receptor (NMDAR) activity by regulating NMDAR subunit 2B (NR2B) surface expression. In the amygdala, NMDA-dependent synaptic plasticity resulting from convergent somatosensory and auditory inputs contributes to emotional memory; however, the role of Src…

  14. Anatomical abnormalities in gray and white matter of the cortical surface in persons with schizophrenia.

    Directory of Open Access Journals (Sweden)

    Tiziano Colibazzi

    Full Text Available Although schizophrenia has been associated with abnormalities in brain anatomy, imaging studies have not fully determined the nature and relative contributions of gray matter (GM and white matter (WM disturbances underlying these findings. We sought to determine the pattern and distribution of these GM and WM abnormalities. Furthermore, we aimed to clarify the contribution of abnormalities in cortical thickness and cortical surface area to the reduced GM volumes reported in schizophrenia.We recruited 76 persons with schizophrenia and 57 healthy controls from the community and obtained measures of cortical and WM surface areas, of local volumes along the brain and WM surfaces, and of cortical thickness.We detected reduced local volumes in patients along corresponding locations of the brain and WM surfaces in addition to bilateral greater thickness of perisylvian cortices and thinner cortex in the superior frontal and cingulate gyri. Total cortical and WM surface areas were reduced. Patients with worse performance on the serial-position task, a measure of working memory, had a higher burden of WM abnormalities.Reduced local volumes along the surface of the brain mirrored the locations of abnormalities along the surface of the underlying WM, rather than of abnormalities of cortical thickness. Moreover, anatomical features of white matter, but not cortical thickness, correlated with measures of working memory. We propose that reductions in WM and smaller total cortical surface area could be central anatomical abnormalities in schizophrenia, driving, at least partially, the reduced regional GM volumes often observed in this illness.

  15. ANIMAL MANURE – REDUCED QUALITY BY ANAEROBIC DIGESTION?

    DEFF Research Database (Denmark)

    Løes, Anne-Kristin; Johansen, Anders; Pommeresche, Reidun

    2014-01-01

    Anaerobic digestion may reduce emissions of greenhouse gases, but we know little about its impact on soil fertility. Reduced concentrations of easily degradable C in the manure may imply less food for the soil fauna and microflora. A field experiment to study its effect on crop yields and soil...... caused the death of both surface-dwelling and soil-living earthworms shortly after application, but the long-term effect of manure application seemed more positive, especially at low application levels. So far, we have observed only small differences in the effects of digested and undigested manure...

  16. Influence of Shrinkage-Reducing Admixtures on the Development of Plastic Shrinkage Cracks

    DEFF Research Database (Denmark)

    Lura, Pietro; Pease, Bradley Justin; Mazzotta, Guy

    2007-01-01

    The term plastic shrinkage cracking is generally used to describe cracks that form between the time when concrete is placed and the time when concrete sets. This paper discusses how the evaporation of water causes concave menisci to form on the surface of fresh concrete. These menisci cause both...... settlement of the concrete and tensile stress development in the surface of the concrete, which increase the potential for development of plastic shrinkage cracks. Specifically, this paper studies the development of plastic shrinkage cracks in mortars containing a commercially available shrinkage-reducing...... admixture (SRA). Mortars containing SRA show fewer and narrower plastic shrinkage cracks than plain mortars when exposed to the same environmental conditions. It is proposed that the lower surface tension of the pore fluid in the mortars containing SRA results in less evaporation, reduced settlement...

  17. Play Matters

    DEFF Research Database (Denmark)

    Sicart (Vila), Miguel Angel

    ? In Play Matters, Miguel Sicart argues that to play is to be in the world; playing is a form of understanding what surrounds us and a way of engaging with others. Play goes beyond games; it is a mode of being human. We play games, but we also play with toys, on playgrounds, with technologies and design......, but not necessarily fun. Play can be dangerous, addictive, and destructive. Along the way, Sicart considers playfulness, the capacity to use play outside the context of play; toys, the materialization of play--instruments but also play pals; playgrounds, play spaces that enable all kinds of play; beauty...

  18. Surface and subsurface cracks characteristics of single crystal SiC wafer in surface machining

    Energy Technology Data Exchange (ETDEWEB)

    Qiusheng, Y., E-mail: qsyan@gdut.edu.cn; Senkai, C., E-mail: senkite@sina.com; Jisheng, P., E-mail: panjisheng@gdut.edu.cn [School of Electromechanical Engineering, Guangdong University of Technology, Guangzhou, 510006 (China)

    2015-03-30

    Different machining processes were used in the single crystal SiC wafer machining. SEM was used to observe the surface morphology and a cross-sectional cleavages microscopy method was used for subsurface cracks detection. Surface and subsurface cracks characteristics of single crystal SiC wafer in abrasive machining were analysed. The results show that the surface and subsurface cracks system of single crystal SiC wafer in abrasive machining including radial crack, lateral crack and the median crack. In lapping process, material removal is dominated by brittle removal. Lots of chipping pits were found on the lapping surface. With the particle size becomes smaller, the surface roughness and subsurface crack depth decreases. When the particle size was changed to 1.5µm, the surface roughness Ra was reduced to 24.0nm and the maximum subsurface crack was 1.2µm. The efficiency of grinding is higher than lapping. Plastic removal can be achieved by changing the process parameters. Material removal was mostly in brittle fracture when grinding with 325# diamond wheel. Plow scratches and chipping pits were found on the ground surface. The surface roughness Ra was 17.7nm and maximum subsurface crack depth was 5.8 µm. When grinding with 8000# diamond wheel, the material removal was in plastic flow. Plastic scratches were found on the surface. A smooth surface of roughness Ra 2.5nm without any subsurface cracks was obtained. Atomic scale removal was possible in cluster magnetorheological finishing with diamond abrasive size of 0.5 µm. A super smooth surface eventually obtained with a roughness of Ra 0.4nm without any subsurface crack.

  19. 3D topography for environmentally friendly machined surfaces

    International Nuclear Information System (INIS)

    Dudas, I; Varga, G

    2005-01-01

    Nowadays more and more scientific paper deals with drilling. In recent years there have been limited changes to the drill design but considerable improvements have been made in the selection of drill materials, drill coatings, flute design and the cutting fluid guiding methods. All of these improvements have been introduced to improve the surface finish of the drilled hole, reduce the energy during drilling process and to reduce ecological damage to the cutting fluids, which carry away heat and debris from the cutting zone. The paper briefly describes the development of surface characterization to its current 3D capability. It shows how selected parameters can assist with drill process analysis and how this can be supported through the introduction of the planned new ISO International Standard for 3D surface characterization. The paper is supported by a sample-drilling test to demonstrate the power of the proposed analysis

  20. Impact of electrode geometry on an atmospheric pressure surface barrier discharge

    Science.gov (United States)

    Hasan, M. I.; Morabit, Y.; Dickenson, A.; Walsh, J. L.

    2017-06-01

    Several of the key characteristics of an atmospheric pressure surface barrier discharge (SBD) are heavily dependent on the geometrical configuration of the plasma generating electrodes. This paper reveals that increasing the surface area of an SBD device by reducing the gaps within the electrodes can have major and unforeseen consequence on the discharge properties. It is experimentally demonstrated that a critical limit exists when reducing the diameter of a circular electrode gap below 5 mm, beyond which the required breakdown voltage increases exponentially and the power deposited in the discharge is impeded. Using a numerical model, it is shown that a reduced electrode gap diameter yields a decrease in the voltage difference between the electrode and dielectric surface, thus lowering the maximum electric field. This study indicates a link between the electrode geometry and the nature of the reactive chemistry produced in the plasma, findings which have wide-reaching implications for many applications where multiple closely packed surface barrier discharges are employed to achieve uniform and large area plasma processing.

  1. Laser polishing for topography management of accelerator cavity surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Liang [College of William and Mary, Williamsburg, VA (United States); Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Klopf, J. Mike [College of William and Mary, Williamsburg, VA (United States); Reece, Charles E. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Kelley, Michael J. [College of William and Mary, Williamsburg, VA (United States); Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)

    2015-07-20

    Improved energy efficiency and reduced cost are greatly desired for advanced particle accelerators. Progress toward both can be made by atomically-smoothing the interior surface of the niobium superconducting radiofrequency accelerator cavities at the machine's heart. Laser polishing offers a green alternative to the present aggressive chemical processes. We found parameters suitable for polishing niobium in all surface states expected for cavity production. As a result, careful measurement of the resulting surface chemistry revealed a modest thinning of the surface oxide layer, but no contamination.

  2. Molecular dynamics simulation of temperature effects on low energy near-surface cascades and surface damage in Cu

    Science.gov (United States)

    Zhu, Guo; Sun, Jiangping; Guo, Xiongxiong; Zou, Xixi; Zhang, Libin; Gan, Zhiyin

    2017-06-01

    The temperature effects on near-surface cascades and surface damage in Cu(0 0 1) surface under 500 eV argon ion bombardment were studied using molecular dynamics (MD) method. In present MD model, substrate system was fully relaxed for 1 ns and a read-restart scheme was introduced to save total computation time. The temperature dependence of damage production was calculated. The evolution of near-surface cascades and spatial distribution of adatoms at varying temperature were analyzed and compared. It was found that near-surface vacancies increased with temperature, which was mainly due to the fact that more atoms initially located in top two layers became adatoms with the decrease of surface binding energy. Moreover, with the increase of temperature, displacement cascades altered from channeling-like structure to branching structure, and the length of collision sequence decreased gradually, because a larger portion of energy of primary knock-on atom (PKA) was scattered out of focused chain. Furthermore, increasing temperature reduced the anisotropy of distribution of adatoms, which can be ascribed to that regular registry of surface lattice atoms was changed with the increase of thermal vibration amplitude of surface atoms.

  3. Molecular dynamics simulation of temperature effects on low energy near-surface cascades and surface damage in Cu

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Guo; Sun, Jiangping; Guo, Xiongxiong; Zou, Xixi; Zhang, Libin; Gan, Zhiyin, E-mail: ganzhiyin@126.com

    2017-06-15

    The temperature effects on near-surface cascades and surface damage in Cu(0 0 1) surface under 500 eV argon ion bombardment were studied using molecular dynamics (MD) method. In present MD model, substrate system was fully relaxed for 1 ns and a read-restart scheme was introduced to save total computation time. The temperature dependence of damage production was calculated. The evolution of near-surface cascades and spatial distribution of adatoms at varying temperature were analyzed and compared. It was found that near-surface vacancies increased with temperature, which was mainly due to the fact that more atoms initially located in top two layers became adatoms with the decrease of surface binding energy. Moreover, with the increase of temperature, displacement cascades altered from channeling-like structure to branching structure, and the length of collision sequence decreased gradually, because a larger portion of energy of primary knock-on atom (PKA) was scattered out of focused chain. Furthermore, increasing temperature reduced the anisotropy of distribution of adatoms, which can be ascribed to that regular registry of surface lattice atoms was changed with the increase of thermal vibration amplitude of surface atoms.

  4. 3-D fracture analysis using a partial-reduced integration scheme

    International Nuclear Information System (INIS)

    Leitch, B.W.

    1987-01-01

    This paper presents details of 3-D elastic-plastic analyses of axially orientated external surface flaw in an internally pressurized thin-walled cylinder and discusses the variation of the J-integral values around the crack tip. A partial-reduced-integration-penalty method is introduced to minimize this variation of the J-integral near the crack tip. Utilizing 3-D symmetry, an eighth segment of a tube containing an elliptically shaped external surface flaw is modelled using 20-noded isoparametric elements. The crack-tip elements are collapsed to form a 1/r stress singularity about the curved crack front. The finite element model is subjected to internal pressure and axial pressure-generated loads. The virtual crack extension method is used to determine linear elastic stress intensity factors from the J-integral results at various points around the crack front. Despite the different material constants and the thinner wall thickness in this analysis, the elastic results compare favourably with those obtained by other researchers. The nonlinear stress-strain behaviour of the tube material is modelled using an incremental theory of plasticity. Variations of the J-integral values around the curved crack front of the 3-D flaw were seen. These variations could not be resolved by neglecting the immediate crack-tip elements J-integral results in favour of the more remote contour paths or else smoothed out when all the path results are averaged. Numerical incompatabilities in the 20-noded 3-D finite elements used to model the surface flaw were found. A partial-reduced integration scheme, using a combination of full and reduced integration elements, is proposed to determine J-integral results for 3-D fracture analyses. This procedure is applied to the analysis of an external semicircular surface flaw projecting halfway into the tube wall thickness. Examples of the J-integral values, before and after the partial-reduced integration method is employed, are given around the

  5. Surface water storage capacity of twenty tree species in Davis, California

    Science.gov (United States)

    Qingfu Xiao; E. Gregory. McPherson

    2016-01-01

    Urban forestry is an important green infrastructure strategy because healthy trees can intercept rainfall, reducing stormwater runoff and pollutant loading. Surface saturation storage capacity, defined as the thin film of water that must wet tree surfaces before flow begins, is the most important variable influencing rainfall interception processes. Surface storage...

  6. Study on IR Properties of Reduced Graphene Oxide

    Science.gov (United States)

    Ma, Deyue; Li, Xiaoxia; Guo, Yuxiang; Zeng, Yurun

    2018-01-01

    Firstly, the reduced graphene oxide was prepared by modified hummer method and characterized. Then, the complex refractive index of reduced graphene oxide in IR band was tested and its IR absorption and radiation properties were researched by correlated calculation. The results show that reduced graphene oxide prepared by hummer method are multilayered graphene with defects and functional groups on its surface. Its absorption in near and far IR bands is strong, but it’s weaker in middle IR band. At the IR atmosphere Window, its normal spectral emissivity decreases with wavelength increasing, and its total normal spectral emissivity in 3 ∼ 5μm and 8 ∼ 14μm are 0.75 and 0.625, respectively. Therefore, reduced graphene oxide can be used as IR absorption and coating materials and have a great potential in microwave and infrared compatible materials.

  7. Bio-Reduction of Graphene Oxide Using Sulfate-Reducing Bacteria and Its Implication on Anti-Biocorrosion.

    Science.gov (United States)

    Song, Tian-Shun; Tan, Wei-Min; Xie, Jingjing

    2018-08-01

    In this paper, we developed an environmental friendly, cost effective, simple and green approach to reduce graphene oxide (GO) by a sulfate-reducing bacterium Desulfovibrio desulfuricans. The D. desulfuricans reduces exfoliated GO to reduced graphene oxide (rGO) at 25 °C in an aqueous solution without any toxic and environmentally harmful reducing agents. The rGO was characterized with X-ray Diffraction, Fourier Transform Infrared Spectroscopy, Scanning Electron Microscopy, Transmission Electron Microscope, X-ray Photoelectron Spectroscopy and Raman Spectroscopy. The analysis results showed that rGO had excellent properties and multi-layer graphene sheets structure. Furthermore, we demonstrated that D. desulfuricans, one of the primary bacteria responsible for the biocorrosion of various metals, might reduce GO to rGO on the surface of copper and prevented the corrosion of copper, which confirmed that electrophoretic deposition of GO on the surface of metals had great potential on the anti-biocorrosion applications.

  8. Reduced near-surface thermal inversions in 2005-06 in the southeastern Arabian Sea (Lakshadweep Sea)

    Digital Repository Service at National Institute of Oceanography (India)

    Nisha, K.; Rao, S.A.; Gopalakrishna, V.V.; Rao, R.R.; GirishKumar, M.S.; Pankajakshan, T.; Ravichandran, M.; Rajesh, S.; Girish, K.; Johnson, Z.; Anuradha, M.; Gavaskar, S.S.M.; Suneel, V.; Krishna, S.M.

    Repeat XBT transects made at near-fortnightly intervals in the Lakshadweep Sea (southeastern Arabian Sea) and ocean data assimilation products are examined to describe the year-to-year variability in the observed near-surface thermal inversions...

  9. Surface concrete decontamination equipment developed by Pacific Northwest Laboratory

    International Nuclear Information System (INIS)

    Halter, J.M.; Sullivan, R.G.; Bevan, J.L.

    1982-08-01

    This report documents a project that the Pacific Northwest Laboratory conducted to identify and develop techniques for removing contaminated concrete surfaces. A major problem associated with nuclear facility decontamination and decommissioning is how to economically demolish and dispose of contaminated concrete. Removing only the contaminated portion of the concrete can substantially reduce costs. Evaluation of various methods for removing concrete surfaces shows that several techniques presently used require excessive manpower, time, and energy. Many times more material is removed than necessary, increasing the quantity of waste that must be handled under controlled conditions. These evaluations generated the basic criteria for developing a suitable concrete removal technique: provide a convenient method for cleaning surfaces (such as those contaminated by a small spill); reduce the contaminated waste volume that has to be placed into controlled storage; remove surfaces quickly; and minimize personal exposure to potentially harmful radiation or toxic materials. Removal to 1/4 to 1/2 in. of contaminated surface layer is sufficient for cleanup of most facilities. Two unique decontamination methods have been developed: the concrete spaller and the water cannon. The concrete spaller is the most efficient technique: it removes the concrete surface faster than the water cannons and at a lower cost (as little as $3.00/ft 2 of concrete surface). However, the .458 magnum water cannon may be well suited for small or hard-to-reach locations

  10. Simulations geometric structures of the stepped profile bearing surface of the piston

    Directory of Open Access Journals (Sweden)

    Wroblewski Emil

    2017-01-01

    Full Text Available The main node piston-pin-piston rings are most responsible for the formation of mechanical losses. It is advisable to reduce friction losses in the piston-cylinder group lead to an increase in the overall efficiency of the engine and thus reduce the fuel consumption. The method to reduce the area covered by the oil film is a modification of the bearing surface of the piston by adjusting the profile. In this paper the results of simulation for the stepped microgeometry piston bearing surface are presented.

  11. A plan to reduce volatile organic compound emissions from consumer products in Canada (excluding windshield washer fluid and surface coatings) : final report

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2000-12-01

    This report highlights the recommendations made by the Canadian Council of Ministers of the Environment for the development of a guideline to provide a means by which to reduce (VOC) emissions from consumer products (excluding windshield washer fluid and surface coatings) in Canada. VOCs and nitrogen oxides react photochemically in the presence of sunlight to create ground-level ozone, a primary component of urban smog which has a detrimental effect on human health, agricultural crops and building materials. In recent years, most urban areas of Canada have shown an annual increase in the maximum acceptable air quality levels for ground level ozone. Reducing emissions of volatile organic compounds (VOCs) from consumer products was first suggested in 1990 by the Canadian Council of Ministers of the Environment in phase one of their program entitled the 'Management plan for nitrogen oxides and volatile organic compounds'. Phase 2 of the program was implemented in 1997 to harmonize the emissions reduction program with the United States Environmental Protection Agency regulations. The Canadian Environmental Protection Agency (CEPA) recommended the following control options: (1) a CEPA guideline should be developed which states the maximum VOC and high-volatility organic compound (HVOC) content in Canadian consumer products including hair care products, herbicides, insecticides, air fresheners, deodorants, fungicides, surface cleaners, fragrance products, anti-microbial agents, laundry products and automotive detailing products. These limits should be identical to those found in the 1998 U.S. Final Rule for Consumer Products, (2) the CEPA guideline should require that records specifying VOC content in weight-per cent be maintained for a period of three years, (3) the CEPA guideline should include a declaration procedure for Canadian importers and manufacturers of consumer products to report to Environment Canada regarding the VOC content of their products, and

  12. Dopant Adsorption and Incorporation at Irradiated GaN Surfaces

    Science.gov (United States)

    Sun, Qiang; Selloni, Annabella; Myers, Thomas; Doolittle, W. Alan

    2006-03-01

    Mg and O are two of the common dopants in GaN, but, in spite of extensive investigation, the atomic scale understanding of their adsorption and incorporation is still incomplete. In particular, high-energy electron irradiation, such as occurring during RHEED, has been reported to have an important effect on the incorporation of these impurities, but no study has addressed the detailed mechanisms of this effect yet. Here we use DFT calculations to study the adsorption and incorporation of Mg and O at the Ga- and N-polar GaN surfaces under various Ga, Mg and O coverage conditions as well as in presence of light or electron beam-induced electronic excitation. We find that the adsorption and incorporation of the two impurities have opposite surface polarity dependence: substitutional Mg prefers to incorporate at the GaN(0001) surface, while O prefers to adsorb and incorporate at the N-polar surface. In addition, our results indicate that in presence of light irradiation the tendency of Mg to surface-segregate is reduced. The O adsorption energy on the N-polar surface is also significantly reduced, consistent with the experimental observation of a much smaller concentration of oxygen in the irradiated samples.

  13. The Influence of the Tool Surface Texture on Friction and the Surface Layers Properties of Formed Component

    Directory of Open Access Journals (Sweden)

    Jana Šugárová

    2018-03-01

    Full Text Available The morphological texturing of forming tool surfaces has high potential to reduce friction and tool wear and also has impact on the surface layers properties of formed material. In order to understand the effect of different types of tool textures, produced by nanosecond fibre laser, on the tribological conditions at the interface tool-formed material and on the integrity of formed part surface layers, the series of experimental investigations have been carried out. The coefficient of friction for different texture parameters (individual feature shape, including the depth profile of the cavities and orientation of the features relative to the material flow was evaluated via a Ring Test and the surface layers integrity of formed material (surface roughness and subsurface micro hardness was also experimentally analysed. The results showed a positive effect of surface texturing on the friction coefficients and the strain hardening of test samples material. Application of surface texture consisting of dimple-like depressions arranged in radial layout contributed to the most significant friction reduction of about 40%. On the other hand, this surface texture contributed to the increase of surface roughness parameters, Ra parameter increased from 0.49 μm to 2.19 μm and the Rz parameter increased from 0.99 μm to 16.79 μm.

  14. Simulated Effects of Land Cover Conversion on the Surface Energy Budget in the Southwest of China

    Directory of Open Access Journals (Sweden)

    Jiangbo Gao

    2014-03-01

    Full Text Available In this paper, the coupled WRF/SSiB model, accompanied by a Karst Rocky Desertification (KRD map of the Guizhou Karst Plateau (GKP of China, was applied to detect how the changed vegetation and soil characteristics over the GKP modify the energy balance at the land surface. The results indicated that land degradation led to reduced net radiation by inducing more upward shortwave and longwave radiation, which were associated with increasing surface albedo and temperature, respectively. The KRD also resulted in changed surface energy partitioning into sensible and latent heat fluxes. The latent heat flux at land surface was reduced substantially due to the higher surface albedo and stomatal resistance, the lower Leaf Area Index (LAI and roughness length in the degradation experiment, while the sensible heat flux increased, mainly because of the higher surface temperature. Furthermore, the moisture flux convergence was reduced, owing to the lower atmospheric heating and the relative subsidence. However, compared with the reduced evaporation, the decrease in moisture flux convergence contributed much less to the reduced precipitation. Precipitation strongly affects soil moisture, vegetation growth and phenology, and thus evaporation and convective latent heating, so when precipitation was changed, a feedback loop was created.

  15. DOUBLE SHEAR DESIGN TO REDUCED STAMPING FORCE

    Directory of Open Access Journals (Sweden)

    Rudi Kurniawan Arief

    2017-12-01

    Full Text Available Ideally processing of part using stamping machine using only 70-80 % of available force to keep machine in good shape for a long periods. But in some certain case the force may equal to or exceed the available maximum force so the company must sent the process to another outsource company. A case found in a metal stamping company where a final product consist of 3 parts to assembly with one part exceeded the force of available machine. This part can only process in a 1000 tons machine while this company only have 2 of this machine with full workload. Sending this parts outsource will induce delivery problems because other parts are processed, assembled and paint inhouse, this also need additional transportation cost and extra supervision to ensure the quality and delivery schedule. The only exit action of this problem is by reducing the force tonnage. This paper using punch inclining method to reduce the force. The incline punch will distributed the force along the inclined surface that reduce stamping force as well. Inclined surface of punch also cause another major problems that the product becoming curved after process. This problems solved with additional flattening process that add more process cost but better than to outsource the process. Chisel type of inclining punch tip was choosen to avoid worst deformation of product. This paper will give the scientific recomendation to the company.

  16. Stabilization of Leidenfrost vapour layer by textured superhydrophobic surfaces

    KAUST Repository

    Vakarelski, Ivan Uriev

    2012-09-12

    In 1756, Leidenfrost observed that water drops skittered on a sufficiently hot skillet, owing to levitation by an evaporative vapour film. Such films are stable only when the hot surface is above a critical temperature, and are a central phenomenon in boiling. In this so-called Leidenfrost regime, the low thermal conductivity of the vapour layer inhibits heat transfer between the hot surface and the liquid. When the temperature of the cooling surface drops below the critical temperature, the vapour film collapses and the system enters a nucleate-boiling regime, which can result in vapour explosions that are particularly detrimental in certain contexts, such as in nuclear power plants. The presence of these vapour films can also reduce liquid-solid drag. Here we show how vapour film collapse can be completely suppressed at textured superhydrophobic surfaces. At a smooth hydrophobic surface, the vapour film still collapses on cooling, albeit at a reduced critical temperature, and the system switches explosively to nucleate boiling. In contrast, at textured, superhydrophobic surfaces, the vapour layer gradually relaxes until the surface is completely cooled, without exhibiting a nucleate-boiling phase. This result demonstrates that topological texture on superhydrophobic materials is critical in stabilizing the vapour layer and thus in controlling-by heat transfer-the liquid-gas phase transition at hot surfaces. This concept can potentially be applied to control other phase transitions, such as ice or frost formation, and to the design of low-drag surfaces at which the vapour phase is stabilized in the grooves of textures without heating. © 2012 Macmillan Publishers Limited. All rights reserved.

  17. Stabilization of Leidenfrost vapour layer by textured superhydrophobic surfaces

    KAUST Repository

    Vakarelski, Ivan Uriev; Patankar, Neelesh A.; Marston, Jeremy; Chan, Derek Y C; Thoroddsen, Sigurdur T

    2012-01-01

    In 1756, Leidenfrost observed that water drops skittered on a sufficiently hot skillet, owing to levitation by an evaporative vapour film. Such films are stable only when the hot surface is above a critical temperature, and are a central phenomenon in boiling. In this so-called Leidenfrost regime, the low thermal conductivity of the vapour layer inhibits heat transfer between the hot surface and the liquid. When the temperature of the cooling surface drops below the critical temperature, the vapour film collapses and the system enters a nucleate-boiling regime, which can result in vapour explosions that are particularly detrimental in certain contexts, such as in nuclear power plants. The presence of these vapour films can also reduce liquid-solid drag. Here we show how vapour film collapse can be completely suppressed at textured superhydrophobic surfaces. At a smooth hydrophobic surface, the vapour film still collapses on cooling, albeit at a reduced critical temperature, and the system switches explosively to nucleate boiling. In contrast, at textured, superhydrophobic surfaces, the vapour layer gradually relaxes until the surface is completely cooled, without exhibiting a nucleate-boiling phase. This result demonstrates that topological texture on superhydrophobic materials is critical in stabilizing the vapour layer and thus in controlling-by heat transfer-the liquid-gas phase transition at hot surfaces. This concept can potentially be applied to control other phase transitions, such as ice or frost formation, and to the design of low-drag surfaces at which the vapour phase is stabilized in the grooves of textures without heating. © 2012 Macmillan Publishers Limited. All rights reserved.

  18. Measurement of near neighbor separations of surface atoms

    International Nuclear Information System (INIS)

    Cohen, P.I.

    Two techniques are being developed to measure the nearest neighbor distances of atoms at the surfaces of solids. Both measures extended fine structure in the excitation probability of core level electrons which are excited by an incident electron beam. This is an important problem because the structures of most surface systems are as yet unknown, even though the location of surface atoms is the basis for any quantitative understanding of the chemistry and physics of surfaces and interfaces. These methods would allow any laboratory to make in situ determinations of surface structure in conjunction with most other laboratory probes of surfaces. Each of these two techniques has different advantages; further, the combination of the two will increase confidence in the results by reducing systematic error in the data analysis

  19. Surface engineering of ferroelectric polymer for the enhanced electrical performance of organic transistor memory

    Science.gov (United States)

    Kim, Do-Kyung; Lee, Gyu-Jeong; Lee, Jae-Hyun; Kim, Min-Hoi; Bae, Jin-Hyuk

    2018-05-01

    We suggest a viable surface control method to improve the electrical properties of organic nonvolatile memory transistors. For viable surface control, the surface of the ferroelectric insulator in the memory field-effect transistors was modified using a smooth-contact-curing process. For the modification of the ferroelectric polymer, during the curing of the ferroelectric insulators, the smooth surface of a soft elastomer contacts intimately with the ferroelectric surface. This smooth-contact-curing process reduced the surface roughness of the ferroelectric insulator without degrading its ferroelectric properties. The reduced roughness of the ferroelectric insulator increases the mobility of the organic field-effect transistor by approximately eight times, which results in a high memory on–off ratio and a low-voltage reading operation.

  20. Modeling marine surface microplastic transport to assess optimal removal locations

    Science.gov (United States)

    Sherman, Peter; van Sebille, Erik

    2016-01-01

    Marine plastic pollution is an ever-increasing problem that demands immediate mitigation and reduction plans. Here, a model based on satellite-tracked buoy observations and scaled to a large data set of observations on microplastic from surface trawls was used to simulate the transport of plastics floating on the ocean surface from 2015 to 2025, with the goal to assess the optimal marine microplastic removal locations for two scenarios: removing the most surface microplastic and reducing the impact on ecosystems, using plankton growth as a proxy. The simulations show that the optimal removal locations are primarily located off the coast of China and in the Indonesian Archipelago for both scenarios. Our estimates show that 31% of the modeled microplastic mass can be removed by 2025 using 29 plastic collectors operating at a 45% capture efficiency from these locations, compared to only 17% when the 29 plastic collectors are moored in the North Pacific garbage patch, between Hawaii and California. The overlap of ocean surface microplastics and phytoplankton growth can be reduced by 46% at our proposed locations, while sinks in the North Pacific can only reduce the overlap by 14%. These results are an indication that oceanic plastic removal might be more effective in removing a greater microplastic mass and in reducing potential harm to marine life when closer to shore than inside the plastic accumulation zones in the centers of the gyres.

  1. Modeling marine surface microplastic transport to assess optimal removal locations

    International Nuclear Information System (INIS)

    Sherman, Peter; Van Sebille, Erik

    2016-01-01

    Marine plastic pollution is an ever-increasing problem that demands immediate mitigation and reduction plans. Here, a model based on satellite-tracked buoy observations and scaled to a large data set of observations on microplastic from surface trawls was used to simulate the transport of plastics floating on the ocean surface from 2015 to 2025, with the goal to assess the optimal marine microplastic removal locations for two scenarios: removing the most surface microplastic and reducing the impact on ecosystems, using plankton growth as a proxy. The simulations show that the optimal removal locations are primarily located off the coast of China and in the Indonesian Archipelago for both scenarios. Our estimates show that 31% of the modeled microplastic mass can be removed by 2025 using 29 plastic collectors operating at a 45% capture efficiency from these locations, compared to only 17% when the 29 plastic collectors are moored in the North Pacific garbage patch, between Hawaii and California. The overlap of ocean surface microplastics and phytoplankton growth can be reduced by 46% at our proposed locations, while sinks in the North Pacific can only reduce the overlap by 14%. These results are an indication that oceanic plastic removal might be more effective in removing a greater microplastic mass and in reducing potential harm to marine life when closer to shore than inside the plastic accumulation zones in the centers of the gyres. (letter)

  2. Thermal repellent properties of surface coating using silica

    Science.gov (United States)

    Lee, Y. Y.; Halim, M. S.; Aminudin, E.; Guntor, N. A.

    2017-11-01

    Extensive land development in urban areas is completely altering the surface profile of human living environment. As cities growing rapidly, impervious building and paved surfaces are replacing the natural landscape. In the developing countries with tropical climate, large masses of building elements, such as brick wall and concrete members, absorb and store large amount of heat, which in turn radiate back to the surrounding air during the night time. This bubble of heat is known as urban heat island (UHI). The use of high albedo urban surfaces is an inexpensive measure that can reduce surrounded temperature. Thus, the main focus of this study is to investigate the ability of silica, SiO2, with high albedo value, to be used as a thermal-repelled surface coating for brick wall. Three different silica coatings were used, namely silicone resin, silicone wax and rain repellent and one exterior commercial paint (jota shield paint) that commercially available in the market were applied on small-scale brick wall models. An uncoated sample also had been fabricated as a control sample for comparison. These models were placed at the outdoor space for solar exposure. Outdoor environment measurement was carried out where the ambient temperature, surface temperature, relative humidity and UV reflectance were recorded. The effect of different type of surface coating on temperature variation of the surface brick wall and the thermal performance of coatings as potential of heat reduction for brick wall have been studied. Based on the results, model with silicone resin achieved the lowest surface temperature which indicated that SiO2 can be potentially used to reduce heat absorption on the brick wall and further retains indoor passive thermal comfortability.

  3. Ultra Low Noise Poroelastic Road Surfaces

    Directory of Open Access Journals (Sweden)

    Jerzy A. Ejsmont

    2016-04-01

    Full Text Available Noise is one of the most important environmental problems related to road traffic. During the last decades, the noise emitted by the engines and powertrains of vehicles was greatly reduced and tires became a clearly dominant noise source. The article describes the concept of low noise poroelastic road surfaces that are composed of mineral and rubber aggregate bound by polyurethane resin. Those surfaces have a porous structure and are much more flexible than standard asphalt or cement concrete pavements due to high content of rubber aggregate and elastic binder. Measurements performed in several European countries indicate that such surfaces decrease tire/road noise between 7 dB and 12 dB with respect to reference surfaces such as dense asphalt concrete or stone matrix asphalt. Furthermore, poroelastic road surfaces ascertain the rolling resistance of car tires, which is comparable to classic pavements. One of the unforeseen properties of the poroelastic road surfaces is their ability to decrease the risks related to car fires with fuel spills. The article presents the road and laboratory results of noise, rolling resistance, and fire tests performed on a few types of poroelastic road surfaces.

  4. Surface chemistry interventions to control boiler tube fouling

    International Nuclear Information System (INIS)

    Turner, C.W.; Guzonas, D.A.; Klimas, S.J.

    2000-06-01

    The adsorption of ammonia, morpholine, ethanolamine, and dimethylamine onto the surfaces of colloidal magnetite and hematite was measured at 25 o C. The effect of the adsorption on the surface potential was quantified by measuring the resulting shift in the isoelectric point of the corrosion products and by the direct measurement of the surface interaction force between the corrosion products and Inconel 600. These measurements have served to support the hypothesis that adsorption of amine affects the magnetite deposition rate by lowering the force of repulsion between magnetite and the surface of Inconel 600. The deposition rate of hematite increased as the oxygen concentration increased. A mechanism to account for enhanced deposition rates at high mixture qualities (> 0.35) has been identified and shown to predict behaviour that is consistent with both experimental and plant data. As a result of this investigation, several criteria are proposed to reduce the extent of corrosion product deposition on the tube bundle. Low hematite deposition is favoured by a low concentration of dissolved oxygen, and low magnetite deposition is favoured by choosing an amine for pH control that has little tendency to adsorb onto the surface of magnetite. To minimize adsorption the amine should have a high base strength and a large 'footprint' on the surface of magnetite. To prevent enhanced deposition at high mixture qualities, it is proposed that a modified amine be used that will reduce the surface tension or the elasticity of the steam-water interface or both

  5. Surface chemistry interventions to control boiler tube fouling

    Energy Technology Data Exchange (ETDEWEB)

    Turner, C.W.; Guzonas, D.A.; Klimas, S.J

    2000-06-01

    The adsorption of ammonia, morpholine, ethanolamine, and dimethylamine onto the surfaces of colloidal magnetite and hematite was measured at 25{sup o}C. The effect of the adsorption on the surface potential was quantified by measuring the resulting shift in the isoelectric point of the corrosion products and by the direct measurement of the surface interaction force between the corrosion products and Inconel 600. These measurements have served to support the hypothesis that adsorption of amine affects the magnetite deposition rate by lowering the force of repulsion between magnetite and the surface of Inconel 600. The deposition rate of hematite increased as the oxygen concentration increased. A mechanism to account for enhanced deposition rates at high mixture qualities (> 0.35) has been identified and shown to predict behaviour that is consistent with both experimental and plant data. As a result of this investigation, several criteria are proposed to reduce the extent of corrosion product deposition on the tube bundle. Low hematite deposition is favoured by a low concentration of dissolved oxygen, and low magnetite deposition is favoured by choosing an amine for pH control that has little tendency to adsorb onto the surface of magnetite. To minimize adsorption the amine should have a high base strength and a large 'footprint' on the surface of magnetite. To prevent enhanced deposition at high mixture qualities, it is proposed that a modified amine be used that will reduce the surface tension or the elasticity of the steam-water interface or both.

  6. Colonization on root surface by a phenanthrene-degrading endophytic bacterium and its application for reducing plant phenanthrene contamination.

    Directory of Open Access Journals (Sweden)

    Juan Liu

    Full Text Available A phenanthrene-degrading endophytic bacterium, Pn2, was isolated from Alopecurus aequalis Sobol grown in soils contaminated with polycyclic aromatic hydrocarbons (PAHs. Based on morphology, physiological characteristics and the 16S rRNA gene sequence, it was identified as Massilia sp. Strain Pn2 could degrade more than 95% of the phenanthrene (150 mg · L(-1 in a minimal salts medium (MSM within 48 hours at an initial pH of 7.0 and a temperature of 30 °C. Pn2 could grow well on the MSM plates with a series of other PAHs, including naphthalene, acenaphthene, anthracene and pyrene, and degrade them to different degrees. Pn2 could also colonize the root surface of ryegrass (Lolium multiflorum Lam, invade its internal root tissues and translocate into the plant shoot. When treated with the endophyte Pn2 under hydroponic growth conditions with 2 mg · L(-1 of phenanthrene in the Hoagland solution, the phenanthrene concentrations in ryegrass roots and shoots were reduced by 54% and 57%, respectively, compared with the endophyte-free treatment. Strain Pn2 could be a novel and useful bacterial resource for eliminating plant PAH contamination in polluted environments by degrading the PAHs inside plants. Furthermore, we provide new perspectives on the control of the plant uptake of PAHs via endophytic bacteria.

  7. Laser Surface Alloying of Aluminum for Improving Acid Corrosion Resistance

    Science.gov (United States)

    Jiru, Woldetinsay Gutu; Sankar, Mamilla Ravi; Dixit, Uday Shanker

    2018-04-01

    In the present study, laser surface alloying of aluminum with magnesium, manganese, titanium and zinc, respectively, was carried out to improve acid corrosion resistance. Laser surface alloying was conducted using 1600 and 1800 W power source using CO2 laser. Acid corrosion resistance was tested by dipping the samples in a solution of 2.5% H2SO4 for 200 h. The weight loss due to acid corrosion was reduced by 55% for AlTi, 41% for AlMg alloy, 36% for AlZn and 22% for AlMn alloy. Laser surface alloyed samples offered greater corrosion resistance than the aluminum substrate. It was observed that localized pitting corrosion was the major factor to damage the surface when exposed for a long time. The hardness after laser surface alloying was increased by a factor of 8.7, 3.4, 2.7 and 2 by alloying with Mn, Mg, Ti and Zn, respectively. After corrosion test, hardness was reduced by 51% for AlTi sample, 40% for AlMg sample, 41.4% for AlMn sample and 33% for AlZn sample.

  8. Size effect of the elastic modulus of rectangular nanobeams: Surface elasticity effect

    International Nuclear Information System (INIS)

    Yao Hai-Yan; Fan Wen-Liang; Yun Guo-Hong

    2013-01-01

    The size-dependent elastic property of rectangular nanobeams (nanowires or nanoplates) induced by the surface elasticity effect is investigated by using a developed modified core-shell model. The effect of surface elasticity on the elastic modulus of nanobeams can be characterized by two surface related parameters, i.e., inhomogeneous degree constant and surface layer thickness. The analytical results show that the elastic modulus of the rectangular nanobeam exhibits a distinct size effect when its characteristic size reduces below 100 nm. It is also found that the theoretical results calculated by a modified core-shell model have more obvious advantages than those by other models (core-shell model and core-surface model) by comparing them with relevant experimental measurements and computational results, especially when the dimensions of nanostructures reduce to a few tens of nanometers. (condensed matter: structural, mechanical, and thermal properties)

  9. Reduced in vivo ocular surface toxicity with polyquad-preserved travoprost versus benzalkonium-preserved travoprost or latanoprost ophthalmic solutions.

    Science.gov (United States)

    Liang, Hong; Brignole-Baudouin, Françoise; Riancho, Luisa; Baudouin, Christophe

    2012-01-01

    The study used a validated acute in vivo model to compare a new formulation of travoprost 0.004% ophthalmic solution(travoprost PQ), preserved with polyquaternium-1 (PQ), with commercially available formulations of benzalkonium-chloride(BAK)-preserved travoprost 0.004% ophthalmic solution(travoprost BAK) and BAK-preserved latanoprost 0.005%ophthalmic solution (latanoprost BAK). Adult male New Zealand albino rabbits (n = 36) were randomly divided into 6 groups. Phosphate-buffered saline (PBS), 0.001% PQ, 0.015% BAK, travoprost PQ, travoprost BAK or latanoprost BAK were applied onto rabbit eyes as 1 drop, for 15 times at 5-min intervals.The ocular surface reactions were investigated at hour 4 and day 1 using slitlamp examination; in vivo confocal microscopy (IVCM) for cornea, limbus and conjunctiva/conjunctiva-associated lymphoid tissue, conjunctival impression cytology and standard immunohistology in cryosections for detecting CD45+ infiltrating cells and MUC-5AC-labeled cells. PBS, PQ and travoprost PQ did not induce obvious irritation by clinical observation, changes in microstructures of the whole ocular surface as measured by IVCM analysis,inflammatory infiltration or cell damage as measured by impression cytology, altered levels of goblet cell counts or numerous CD45+ cells in the cornea. In contrast, all BAK-containing products induced diffuse conjunctival hyperemia and chemosis, abnormal changes in the ocular surface microstructure,significant total ocular surface toxicity scores,damaged epithelial cells, inflammatory cell infiltration and decreased goblet cell density. Travoprost PQ did not elicitocular surface toxicity when administered to rabbit eyes.These results suggest a greater safety advantage for the ocular surface of patients receiving chronic glaucoma treatment with PQ-preserved drugs.

  10. Soil surface temperatures reveal moderation of the urban heat island effect by trees and shrubs

    DEFF Research Database (Denmark)

    Edmondson, Jill L; Stott, Iain; Davies, Zoe G

    2016-01-01

    months increased by 0.6 °C over the 5 km from the city outskirts to the centre. Trees and shrubs in non-domestic greenspace reduced mean maximum daily soil surface temperatures in the summer by 5.7 °C compared to herbaceous vegetation, but tended to maintain slightly higher temperatures in winter. Trees...... in domestic gardens, which tend to be smaller, were less effective at reducing summer soil surface temperatures. Our findings reveal that the UHI effects soil temperatures at a city-wide scale, and that in their moderating urban soil surface temperature extremes, trees and shrubs may help to reduce...

  11. Reducing carbon dioxide to products

    Science.gov (United States)

    Cole, Emily Barton; Sivasankar, Narayanappa; Parajuli, Rishi; Keets, Kate A

    2014-09-30

    A method reducing carbon dioxide to one or more products may include steps (A) to (C). Step (A) may bubble said carbon dioxide into a solution of an electrolyte and a catalyst in a divided electrochemical cell. The divided electrochemical cell may include an anode in a first cell compartment and a cathode in a second cell compartment. The cathode may reduce said carbon dioxide into said products. Step (B) may adjust one or more of (a) a cathode material, (b) a surface morphology of said cathode, (c) said electrolyte, (d) a manner in which said carbon dioxide is bubbled, (e), a pH level of said solution, and (f) an electrical potential of said divided electrochemical cell, to vary at least one of (i) which of said products is produced and (ii) a faradaic yield of said products. Step (C) may separate said products from said solution.

  12. Integrated biomechanical and topographical surface characterization (IBTSC)

    Energy Technology Data Exchange (ETDEWEB)

    Löberg, Johanna, E-mail: Johanna.Loberg@dentsply.com [Dentsply Implants, Box 14, SE-431 21 Mölndal (Sweden); Mattisson, Ingela [Dentsply Implants, Box 14, SE-431 21 Mölndal (Sweden); Ahlberg, Elisabet [Department of Chemistry and Molecular Biology, University of Gothenburg, SE-41296 Gothenburg (Sweden)

    2014-01-30

    In an attempt to reduce the need for animal studies in dental implant applications, a new model has been developed which combines well-known surface characterization methods with theoretical biomechanical calculations. The model has been named integrated biomechanical and topographical surface characterization (IBTSC), and gives a comprehensive description of the surface topography and the ability of the surface to induce retention strength with bone. IBTSC comprises determination of 3D-surface roughness parameters by using 3D-scanning electron microscopy (3D-SEM) and atomic force microscopy (AFM), and calculation of the ability of different surface topographies to induce retention strength in bone by using the local model. Inherent in this integrated approach is the use of a length scale analysis, which makes it possible to separate different size levels of surface features. The IBTSC concept is tested on surfaces with different level of hierarchy, induced by mechanical as well as chemical treatment. Sequential treatment with oxalic and hydrofluoric acid results in precipitated nano-sized features that increase the surface roughness and the surface slope on the sub-micro and nano levels. This surface shows the highest calculated shear strength using the local model. The validity, robustness and applicability of the IBTSC concept are demonstrated and discussed.

  13. Phenylboronic acid functionalized reduced graphene oxide based fluorescence nano sensor for glucose sensing

    Energy Technology Data Exchange (ETDEWEB)

    Basiruddin, SK; Swain, Sarat K., E-mail: swainsk2@yahoo.co.in

    2016-01-01

    Reduced graphene has emerged as promising tools for detection based application of biomolecules as it has high surface area with strong fluorescence quenching property. We have used the concept of fluorescent quenching property of reduced graphene oxide to the fluorescent probes which are close vicinity of its surface. In present work, we have synthesized fluorescent based nano-sensor consist of phenylboronic acid functionalized reduced graphene oxide (rGO–PBA) and di-ol modified fluorescent probe for detection of biologically important glucose molecules. This fluorescent graphene based nano-probe has been characterized by high resolution transmission electron microscope (HRTEM), Atomic force microscope (AFM), UV–visible, Photo-luminescence (PL) and Fourier transformed infrared (FT-IR) spectroscopy. Finally, using this PBA functionalized reduced GO based nano-sensor, we were able to detect glucose molecule in the range of 2 mg/mL to 75 mg/mL in aqueous solution of pH 7.4. - Highlights: • Easy and simple synthesis of PBA functionalized reduced GO based nano probe. • PBA functionalized reduced GO graphene based nano-probes are characterized. • PBA functionalized reduced GO nano probe is used to detect glucose molecules. • It is very cost-effective and enzyme-free detection of glucose in solution.

  14. Rapid pulse annealing of CdZnTe detectors for reducing electronic noise

    Science.gov (United States)

    Voss, Lars; Conway, Adam; Nelson, Art; Nikolic, Rebecca J.; Payne, Stephen A.; Swanberg, Jr., Erik Lars

    2018-05-01

    A combination of doping, rapid pulsed optical and/or thermal annealing, and unique detector structure reduces or eliminates sources of electronic noise in a CdZnTe (CZT) detector. According to several embodiments, methods of forming a detector exhibiting minimal electronic noise include: pulse-annealing at least one surface of a detector comprising CZT for one or more pulses, each pulse having a duration of .about.0.1 seconds or less. The at least one surface may optionally be ion-implanted. In another embodiment, a CZT detector includes a detector surface with two or more electrodes operating at different electric potentials and coupled to the detector surface; and one or more ion-implanted CZT surfaces on or in the detector surface, each of the one or more ion-implanted CZT surfaces being independently connected to one of the two or more electrodes and the surface of the detector. At least two of the ion-implanted surfaces are in electrical contact.

  15. The multiverse is your playground

    Science.gov (United States)

    Levine, Alaina G.

    2018-01-01

    Astronomers should not feel like failures for leaving academia — the multiverse is replete with engaging, satisfying and well-remunerated jobs that will value you, your education, your training and your unique skills.

  16. Corrected body surface potential mapping.

    Science.gov (United States)

    Krenzke, Gerhard; Kindt, Carsten; Hetzer, Roland

    2007-02-01

    In the method for body surface potential mapping described here, the influence of thorax shape on measured ECG values is corrected. The distances of the ECG electrodes from the electrical heart midpoint are determined using a special device for ECG recording. These distances are used to correct the ECG values as if they had been measured on the surface of a sphere with a radius of 10 cm with its midpoint localized at the electrical heart midpoint. The equipotential lines of the electrical heart field are represented on the virtual surface of such a sphere. It is demonstrated that the character of a dipole field is better represented if the influence of the thorax shape is reduced. The site of the virtual reference electrode is also important for the dipole character of the representation of the electrical heart field.

  17. Soil surface temperatures reveal moderation of the urban heat island effect by trees and shrubs.

    Science.gov (United States)

    Edmondson, J L; Stott, I; Davies, Z G; Gaston, K J; Leake, J R

    2016-09-19

    Urban areas are major contributors to air pollution and climate change, causing impacts on human health that are amplified by the microclimatological effects of buildings and grey infrastructure through the urban heat island (UHI) effect. Urban greenspaces may be important in reducing surface temperature extremes, but their effects have not been investigated at a city-wide scale. Across a mid-sized UK city we buried temperature loggers at the surface of greenspace soils at 100 sites, stratified by proximity to city centre, vegetation cover and land-use. Mean daily soil surface temperature over 11 months increased by 0.6 °C over the 5 km from the city outskirts to the centre. Trees and shrubs in non-domestic greenspace reduced mean maximum daily soil surface temperatures in the summer by 5.7 °C compared to herbaceous vegetation, but tended to maintain slightly higher temperatures in winter. Trees in domestic gardens, which tend to be smaller, were less effective at reducing summer soil surface temperatures. Our findings reveal that the UHI effects soil temperatures at a city-wide scale, and that in their moderating urban soil surface temperature extremes, trees and shrubs may help to reduce the adverse impacts of urbanization on microclimate, soil processes and human health.

  18. The surface learned from nature

    Science.gov (United States)

    Lim, H.; Kim, W. D.

    2010-07-01

    In this work, I would like to introduce the emerging surface of nature. The surface in nature, has the multi and optimized function with well organized structure. There are so many examples that we learn and apply to technology. First example is self-cleaning surface. Some plants (such as lotus leaf, taro leaf) and the wings of many large-winged insects (such as moth, butterfly, dragonfly) remain their surface clean in the very dirty environment. This self cleaning effect is accomplished by the superhydrophobic surfaces which exhibit the water contact angle of more than 150° with low sliding angle. Generally, the superhydrophobic surface is made up the two factors. One is the surface composition having the low surface tension energy. The other is the surface morphology of hierarchical structure of micro and nano size. Because almost nature surface have the hierarchical structures range from macro to nano size, their topography strength their function to adjust the life in nature environment. The other example is the surface to use for drag reduction. The skin friction drag causes eruptions of air or water resulting in greater drag as the speed is increased. This drag requires more energy to overcome. The shark skin having the fine sharp-edged grooves about 0.1 mm wide known riblet reduces in skin friction drag by being far away the vortex. Among a lot of fuctional surface, the most exciting surface the back of stenocara a kind of desert beetles. Stenocara use the micrometre-sized patterns of hydrophobic, wax-coated and hydrophilic, non-waxy regions on their backs to capture water from fog. This fog-collecting structure improves the water collection of fog-capture film, condenser, engine, and future building. Here, the efforts to realize these emerging functional surfaces in nature on technology are reported with the fabrication method and their properties, especially for the control of surface wettability.

  19. Experimental study of the effect of the reduced graphene oxide films on nucleate boiling performances of inclined surfaces

    International Nuclear Information System (INIS)

    Kim, Ji Hoon; Kong, Byeong Tak; Kim, Ji Min

    2016-01-01

    For the enhancing the CHF, surface coating techniques are available. Yang et al. performed small scale boiling experiments for the vessel lower head, which was coated by aluminum/copper micro particles. Recently, graphene has received much attention for applications in thermal engineering due to its large thermal conductivity. Ahn et al. used a silicon dioxide substrate, which was coated graphene films, as a heating surface during pool boiling experiments. The graphene films inhibited the formation of hot spots, increasing the CHF. For applying novel material 'Graphene' in nuclear industry, here we investigated the effects of graphene film coatings on boiling performances. The experimental pool boiling facility, copying the geometry of lower head of reactor, was designed for verifying orientation effects. The effects of graphene films coating on varied inclined heater surfaces were investigated. The CHF values were increased at every case, but the increased amounts were decreased for downward heater surfaces. At the downward-facing region, however, coating the RGO films would change the CHF mechanisms and boiling heat transfer performances. Generally, RGO films, made by colloidal fabrication, has defects on each flakes.

  20. Reducing Staphylococcus aureus biofilm formation on stainless steel 316L using functionalized self-assembled monolayers

    International Nuclear Information System (INIS)

    Kruszewski, Kristen M.; Nistico, Laura; Longwell, Mark J.; Hynes, Matthew J.; Maurer, Joshua A.; Hall-Stoodley, Luanne; Gawalt, Ellen S.

    2013-01-01

    Stainless steel 316L (SS316L) is a common material used in orthopedic implants. Bacterial colonization of the surface and subsequent biofilm development can lead to refractory infection of the implant. Since the greatest risk of infection occurs perioperatively, strategies that reduce bacterial adhesion during this time are important. As a strategy to limit bacterial adhesion and biofilm formation on SS316L, self-assembled monolayers (SAMs) were used to modify the SS316L surface. SAMs with long alkyl chains terminated with hydrophobic (− CH 3 ) or hydrophilic (oligoethylene glycol) tail groups were used to form coatings and in an orthogonal approach, SAMs were used to immobilize gentamicin or vancomycin on SS316L for the first time to form an “active” antimicrobial coating to inhibit early biofilm development. Modified SS316L surfaces were characterized using surface infrared spectroscopy, contact angles, MALDI-TOF mass spectrometry and atomic force microscopy. The ability of SAM-modified SS316L to retard biofilm development by Staphylococcus aureus was functionally tested using confocal scanning laser microscopy with COMSTAT image analysis, scanning electron microscopy and colony forming unit analysis. Neither hydrophobic nor hydrophilic SAMs reduced biofilm development. However, gentamicin-linked and vancomycin-linked SAMs significantly reduced S. aureus biofilm formation for up to 24 and 48 h, respectively. - Highlights: ► SS316L was modified with glycol terminated SAMs in order to reduce biofilm growth. ► Antibiotics gentamicin and vancomycin were immobilized on SS316L via SAMs. ► Only the antibiotic modifications reduced biofilm development on SS316L