4,684 research outputs found
The response of smoke detectors to pyrolysis and combustion products from aircraft interior materials
The following projects were completed as part of the effort to develop and test economically feasible fire-resistant materials for interior furnishings of aircraft as well as detectors of incipient fires in passenger and cargo compartments: (1) determination of the sensitivity of various contemporary gas and smoke detectors to pyrolysis and combustion products from materials commonly used in aircraft interiors and from materials that may be used in the future, (2) assessment of the environmental limitations to detector sensitivity and reliability. The tests were conducted on three groups of materials by exposure to the following three sources of exposure: radiant and Meeker burner flame, heated coil, and radiant source only. The first test series used radiant heat and flame exposures on easily obtainable test materials. Next, four materials were selected from the first group and exposed to an incandescent coil to provide the conditions for smoldering combustion. Finally, radiant heat exposures were used on advanced materials that are not readily available
Study of volatile contaminants in reclaimed water
Different methods were evaluated for reducing the volatile contaminants found in water recovered from urine by distillation. The use of activated carbon, addition of potassium permanganate, and the use of oxidation catalyst are described along with laboratory tests. It is concluded that catalytic decomposition appears to be feasible, and further investigation is recommended
Ink vs Inc: The Influence of Visible Tattoos on Trustworthiness and Learning
An emerging concern for employers is the impact of visible body modification (VBM) in the workplace. Visible body modification includes tattoos, piercings, or implants that are both visible and observable on an individualâs body. The extant research on VBM suggests that employers are hesitant to hire those with visible tattoos or piercings, but fails to address how employees with VBM influence organizational outcomes. This dissertation examines how a specific type of VBM, visible tattoos, influences training and learning by investigating how a trainerâs visible tattoos affect traineesâ perceived trustworthiness and learning in a training context. The study used a sample of 164 undergraduate students and Amazon Mechanical Turk workers to assess reactions to a trainerâs visible tattoos. Subjects were randomly assigned to one of three treatment groups, with the two experimental groups having a trainer with one tattoo or full tattoo sleeves. The results indicated that there were no significant differences between groups for perceived trustworthiness or learning. Similarly, there was no support for the moderating effect of openness to experience, authoritarianism, or learning goal orientation. Social distance was found to moderate the relationship between the treatment and perceived trustworthiness. The findings of this study suggest that for the trainer and tattoos used, visible tattoos do not an impact on training outcomes. As this study was limited to one trainer with one type of tattoos, this preliminary evidence suggests that more research is needed to address the diversity of tattooing and VBM as a whole
Why Websites Work: An Examination of Interdisciplinary Agricultural Center Websites
This study examined the online content of interdisciplinary agricultural center webpages. Content modification dates, mission statements, and content were determined through a content analysis. Many of the websites did not mention a modification date for the content, while many websites had outdated content mostly older than six months. More than two-thirds of the websites provided PDFs that visitor could download to learn more about topics, by many of the websites lacked any media element that was being coded. Additionally, many websites did not use multiple forms of media. More than half of the websites were coded as lacking any social media content or plugins, but out of the websites that did include social media content, Facebook was the most prevalent. The commonalities between the centerâs mission displayed on the website and the content theme were analyzed and chi-square tests provided the degree of association. A significant association existed and an alignment between communication strategies and missions of the centers was concluded, which is important when organizations communicate about agricultural science as indicated by previous literature. It is recommended that centers communicate via their websites in a timely manner and allow modification times to be seen to viewers to show their information is up-to-date. Website media content should also be diversified and communicators of these centers should explore the unique communication opportunities provided by social media. Future research should explore the target audience of interdisciplinary agricultural centers and should analyze the messages centers are using to communicate with those audiences
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Using shared goal setting to improve access and equity: a mixed methods study of the Good Goals intervention
Background: Access and equity in childrenâs therapy services may be improved by directing cliniciansâ use of resources toward specific goals that are important to patients. A practice-change intervention (titled âGood Goalsâ) was designed to achieve this. This study investigated uptake, adoption, and possible effects of that intervention in childrenâs occupational therapy services.
Methods: Mixed methods case studies (n = 3 services, including 46 therapists and 558 children) were conducted. The intervention was delivered over 25 weeks through face-to-face training, team workbooks, and âtools for changeâ. Data were collected before, during, and after the intervention on a range of factors using interviews, a focus group, case note analysis, routine data, document analysis, and researchersâ observations.
Results: Factors related to uptake and adoptions were: mode of intervention delivery, competing demands on therapistsâ time, and leadership by service manager. Service managers and therapists reported that the intervention: helped therapists establish a shared rationale for clinical decisions; increased clarity in service provision; and improved interactions with families and schools. During the study period, therapistsâ behaviours changed: identifying goals, odds ratio 2.4 (95% CI 1.5 to 3.8); agreeing goals, 3.5 (2.4 to 5.1); evaluating progress, 2.0 (1.1 to 3.5). Childrenâs LoT decreased by two months [95% CI â8 to +4 months] across the services. Cost per therapist trained ranged from ÂŁ1,003 to ÂŁ1,277, depending upon service size and therapistsâ salary bands.
Conclusions: Good Goals is a promising quality improvement intervention that can be delivered and adopted in practice and may have benefits. Further research is required to evaluate its: (i) impact on patient outcomes, effectiveness, cost-effectiveness, and (ii) transferability to other clinical contexts
Antibiotic-induced disturbances of the gut microbiota result in accelerated breast tumor growth
The gut microbiota\u27s function in regulating health has seen it linked to disease progression in several cancers. However, there is limited research detailing its influence in breast cancer (BrCa). This study found that antibiotic-induced perturbation of the gut microbiota significantly increases tumor progression in multiple BrCa mouse models. Metagenomics highlights the common loss of several bacterial species following antibiotic administration. One such bacteria
The State of the Circumstellar Medium Surrounding Gamma-Ray Burst Sources and its Effect on the Afterglow Appearance
We present a numerical investigation of the contribution of the presupernova
ejecta of Wolf-Rayet stars to the environment surrounding gamma-ray bursts
(GRBs), and describe how this external matter can affect the observable
afterglow characteristics. An implicit hydrodynamic calculation for massive
stellar evolution is used here to provide the inner boundary conditions for an
explicit hydrodynamical code to model the circumstellar gas dynamics. The
resulting properties of the circumstellar medium are then used to calculate the
deceleration of a relativistic, gas-dynamic jet and the corresponding afterglow
light curve produced as the shock wave propagates through the shocked-wind
medium. We find that variations in the stellar wind drive instabilities that
may produce radial filaments in the shocked-wind region. These comet-like tails
of clumps could give rise to strong temporal variations in the early afterglow
lightcurve. Afterglows may be expected to differ widely among themselves,
depending on the angular anisotropy of the jet and the properties of the
stellar progenitor; a wide diversity of behaviors may be the rule, rather than
the exception.Comment: 17 pages, 7 figures, ApJ in pres
Infall, Fragmentation and Outflow in Sgr B2
Observations of HCO lines and continuum at 1.3 mm towards Sgr B2(N) and
Sgr B2(M) cores were carried out with the SMA. We imaged HCO line
absorption against the continuum cores and the surrounding line emission
clumps. The results show that the majority of the dense gas is falling into the
major cores where massive stars have been formed. The filaments and clumps of
the continuum and gas are detected outside of Sgr B2(N) and Sgr B2(M) cores.
Both the spectra and moment analysis show the presence of outflows from Sgr
B2(M) cores. The HCO gas in the red-shifted outflow of Sgr B2(M) appears
to be excited by a non-LTE process which might be related to the shocks in the
outflow.Comment: 5 pages, 3 figures, Published in J. Physics Conference Serie
Radiation-Hydrodynamic Simulations of Collapse and Fragmentation in Massive Protostellar Cores
We simulate the early stages of the evolution of turbulent, virialized,
high-mass protostellar cores, with primary attention to how cores fragment, and
whether they form a small or large number of protostars. Our simulations use
the Orion adaptive mesh refinement code to follow the collapse from ~0.1 pc
scales to ~10 AU scales, for durations that cover the main fragmentation phase,
using three-dimensional gravito-radiation hydrodynamics. We find that for a
wide range of initial conditions radiation feedback from accreting protostars
inhibits the formation of fragments, so that the vast majority of the collapsed
mass accretes onto one or a few objects. Most of the fragmentation that does
occur takes place in massive, self-shielding disks. These are driven to
gravitational instability by rapid accretion, producing rapid mass and angular
momentum transport that allows most of the gas to accrete onto the central star
rather than forming fragments. In contrast, a control run using the same
initial conditions but an isothermal equation of state produces much more
fragmentation, both in and out of the disk. We conclude that massive cores with
observed properties are not likely to fragment into many stars, so that, at
least at high masses, the core mass function probably determines the stellar
initial mass function. Our results also demonstrate that simulations of massive
star forming regions that do not include radiative transfer, and instead rely
on a barotropic equation of state or optically thin heating and cooling curves,
are likely to produce misleading results.Comment: 23 pages, 18 figures, emulateapj format. Accepted to ApJ. This
version has minor typo fixes and small additions, no significant changes.
Resolution of images severely degraded to fit within size limit. Download the
full paper from http://www.astro.princeton.edu/~krumholz/recent.htm
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