37 research outputs found
Wirkung von transkutaner elektrischer Nervenstimulation auf die Schmerzintensität bei Patienten mit Gonarthrose: systematische Literaturübersicht
Die Gonarthrose gehört zu den häufigsten Gelenkerkrankungen. Die Prävalenz der Gonarthrose wird zwischen 15 – 55% angegeben. Der Schmerz ist das Hauptsymptom einer Gonarthrose. Schmerzen führen zu einer reduzierten Lebensqualität und mindern die Autonomie. Zur Therapie stehen medikamentöse und nichtmedikamentöse Behandlungsmöglichkeiten zur Verfügung. Da bei den medikamentösen Therapien mit unerwünschten Wirkungen gerechnet werden muss, sind nichtmedikamentöse Pflegeinterventionen wichtig. Die TENS ist eine komplementäre Schmerzbehandlungsmethode, bei der durch die Anwendung von elektrischen Impulsen eine Schmerzlinderung bewirkt wird. Die mangelnde Anwendung der TENS und das Fehlen einer deutschen systematischen Literaturübersicht zeigen die Wichtigkeit des Erstellens dieser Arbeit auf
The Piloted Transition to Flaming in Smoldering Fire Retarded and Non-Fire Retarded Polyurethane Foam
Research paper published in the journal 'Fire and Materials' in 2008The piloted transition from smoldering to flaming, though a significant fire safety
concern, has not been previously extensively studied. Experimental results are
presented on the piloted transition from smoldering to flaming in non-fire retarded
(NFR) polyurethane foam and the fire retarded polyurethane foam Pyrell. The
samples are small blocks, vertically placed in the wall of an upward wind tunnel.
The free surface is exposed to an oxidizer flow and a radiant heat flux. The
smolder product gases pass upwards through a pilot. The experiments on NFR
foam show that the smolder velocity and peak smolder temperature, which
increase with the oxygen concentration and heat flux, are strongly correlated to the
transition to flaming event, in that there are minimum values of these parameters
for transition to occur. The existence of a minimum smolder velocity for ignition
supports the concept of a gaseous mixture reaching a lean flammability limit as the
criterion for the transition to flaming. To compensate for the solid- and gas-phase
effects of the fire retardants on the piloted transition in Pyrell, it was necessary to
increase the oxygen concentration and the power supplied to the smolder igniter
and the pilot. The piloted transition is observed in oxygen concentrations above
17% in NFR foam, and above 23% in Pyrell. The results show that although Pyrell
is less flammable than NFR foam, it is still susceptible to smoldering and the
piloted transition to flaming in oxygen-enriched environments, which is of interest
for special applications such as future space missions
A critical appraisal of the social norms approach as an interventional strategy for health-related behavior and attitude change
© 2018 Dempsey, McAlaney and Bewick. The Social Norms Approach is a widely used intervention strategy for promoting positive health-related behaviors. The Approach operates on the premise that individuals misperceive their peers' behaviors and attitudes, with evidence of under- and over-estimations of behaviors and peer approval for a range of positive and negative behaviors respectively. The greater these misperceptions, the more likely an individual is to engage in negative behaviors such as consuming heavier amounts of alcohol and other substances and reduce positive behaviors such as eating healthily and using sun protection. However, there are many complexities associated with the use of social norms feedback in interventions and empirical studies. Many social norms interventions do not attempt to change misperceptions of social norms or measure changes in normative perceptions pre- and post-intervention. This has led to a conflation of generic social norms interventions with those that are explicitly testing the Approach's assumptions that it is misperceptions of peer norms which drive behavior. The aim of the present review was to provide a critical appraisal of the use of the Social Norms Approach as an intervention strategy for health-related behaviors, identify the current issues with its evidence base, highlight key opportunities and challenges facing the approach, and make recommendations for good practice when using the approach. There are three core challenges and areas for improved practice when using the Social Norms Approach. Firstly, improvements in the methodological rigor and clarity of reporting of 'social norms' research, ensuring that studies are testing the approach's assumption of the role of misperceptions on behaviors are differentiated from studies investigating other forms of 'social norms.' Secondly, the need for a more explicit, unified and testable theoretical model outlining the development of normative misperceptions which can be translated into interventional studies. Finally, a need for a more robust evaluation of social norms interventions in addition to randomized controlled trials, such as the inclusion of process evaluations, qualitative studies of participant experiences of social norms feedback, and alternative study designs better suited for real-world public health settings. Such improvements are required to ensure that the Social Norms Approach is adequately tested and evaluated
Pilot study of a repeated random sampling method for surveys focusing on date-specific differences in alcohol consumption among university students
Abstract Background This paper proposes and pilots a repeated random sampling method to promote the likelihood of collecting drinking data equally representative of the behavior of university students at all times through the academic year. Methods From October, 2016, to May, 2017, random samples of 1350 students were selected from the 39,155 undergraduate students enrolled in the fall semester at University of Houston. These students were sent an email inviting them to complete an online survey (entered into a weekly draw for a $50 gift certificate if responded). Results The response rate was low (6%). Among participants who reported drinking in the last week, there was a variation as expected in the amount of drinking observed depending on the time of year (e.g., during exams). Conclusions While the sampling methods show promise, procedures would need to be implemented to substantially increase response rates before the proposed methods could be seen as an advantage over existing survey sampling procedures
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SMOLDER IGNITION OF POLYURETHANE FOAM: EFFECT OF OXYGEN CONCENTRATION
Experiments have been conducted to study the ignition of both forward and opposed smolder of a high void fraction, flexible, polyurethane foam in a forced oxidizer flow. Tests are conducted in a small scale, vertically oriented, combustion chamber with supporting instrumentation. An electrically heated Nichrome wire heater placed between two porous ceramic disks, one of which is in complete contact with the foam surface, is used to supply the necessary power to ignite and sustain a smolder reaction. The gaseous oxidizer, metered via mass flow controllers, is forced through the foam and heater. A constant power is applied to the igniter for a given period of time and the resulting smolder is monitored to determine if smolder is sustained without the assistance of the heater, in which case smolder ignition is considered achieved. Reaction zone temperature and smolder propagation velocities are obtained from the temperature histories of thermocouples embedded at predetermined positions in the foam with junctions placed along the fuel centerline. Tests are conducted with oxygen mass fractions ranging from 0.109 to 1.0 at a velocity of 0.1 mm/s during the ignition period, and 0.7 or 3.0 mm/s during the self-sustained propagation period. The results show a well defined smolder ignition regime primarily determined by two parameters: igniter heat flux, and the time the igniter is powered. These two parameters determine a minimum igniter/foam temperature, and a minimum depth of smolder propagation (char), which are conditions required for ignition to occur. The former is needed to establish a strong smolder reaction, and the latter to reduce heat losses from the incipient smolder reaction to the surrounding environment. The ignition regime is shifted to shorter times for a given igniter heat flux with increasing oxygen mass fraction. A model based on concepts similar to those developed to describe the ignition of solid fuels has been developed that describes well the experimental ignition results
Recommended from our members
SMOLDER IGNITION OF POLYURETHANE FOAM: EFFECT OF OXYGEN CONCENTRATION
Experiments have been conducted to study the ignition of both forward and opposed smolder of a high void fraction, flexible, polyurethane foam in a forced oxidizer flow. Tests are conducted in a small scale, vertically oriented, combustion chamber with supporting instrumentation. An electrically heated Nichrome wire heater placed between two porous ceramic disks, one of which is in complete contact with the foam surface, is used to supply the necessary power to ignite and sustain a smolder reaction. The gaseous oxidizer, metered via mass flow controllers, is forced through the foam and heater. A constant power is applied to the igniter for a given period of time and the resulting smolder is monitored to determine if smolder is sustained without the assistance of the heater, in which case smolder ignition is considered achieved. Reaction zone temperature and smolder propagation velocities are obtained from the temperature histories of thermocouples embedded at predetermined positions in the foam with junctions placed along the fuel centerline. Tests are conducted with oxygen mass fractions ranging from 0.109 to 1.0 at a velocity of 0.1 mm/s during the ignition period, and 0.7 or 3.0 mm/s during the self-sustained propagation period. The results show a well defined smolder ignition regime primarily determined by two parameters: igniter heat flux, and the time the igniter is powered. These two parameters determine a minimum igniter/foam temperature, and a minimum depth of smolder propagation (char), which are conditions required for ignition to occur. The former is needed to establish a strong smolder reaction, and the latter to reduce heat losses from the incipient smolder reaction to the surrounding environment. The ignition regime is shifted to shorter times for a given igniter heat flux with increasing oxygen mass fraction. A model based on concepts similar to those developed to describe the ignition of solid fuels has been developed that describes well the experimental ignition results