110 research outputs found
Comparison of Monomethylhydrazine/Hydroxypropylcellulose and Hydrocarbon/Silica Gels
Experimental studies have been performed to investigate rheology and droplet burning with different types of gelled propellants. Monomethylhydrazine has been gelled with organic hydroxypropylcellulose. JP-8 and RP-1 hydrocarbon gels have been produced with inorganic fumed silica particles. Rheological characterization showed the differences in terms of viscosity and yield stress behavior due to different types of gelling agents. Herschel-Bulkley and Carreau-Yasuda models have been used to characterize the gels with inorganic and organic gelling agents, respectively. First experiments with the Monomethylhydrazine/hydroxypropylcellulose gels showed a typical swelling process during combustion with a flexible viscous droplet surface. Contrary to that, the hydrocarbon/silica gels burned while a rigid silica structure was built, which remained unburned. Burning drop measurements have been compared to the d^2-squared law
Yes, subjective norms are important, but let's not lose sight of cultural differences
The study of social norms has great potential to broaden our understanding of the ways in which cultures are created and maintained. To maximise the benefit of this perspective, it is important to sample cultures widely and to include contexts in which norms are injunctiv
The universal red-giant oscillation pattern; an automated determination with CoRoT data
The CoRoT and Kepler satellites have provided thousands of red-giant
oscillation spectra. The analysis of these spectra requires efficient methods
for identifying all eigenmode parameters. The assumption of new scaling laws
allows us to construct a theoretical oscillation pattern. We then obtain a
highly precise determination of the large separation by correlating the
observed patterns with this reference. We demonstrate that this pattern is
universal and are able to unambiguously assign the eigenmode radial orders and
angular degrees. This solves one of the current outstanding problems of
asteroseismology hence allowing precise theoretical investigation of red-giant
interiors.Comment: Accepted in A&A letter
Micro-Hall Magnetometry Studies of Thermally Assisted and Pure Quantum Tunneling in Single Molecule Magnet Mn12-Acetate
We have studied the crossover between thermally assisted and pure quantum
tunneling in single crystals of high spin (S=10) uniaxial single molecule
magnet Mn12-acetate using micro-Hall effect magnetometry. Magnetic hysteresis
experiments have been used toinvestigate the energy levels that determine the
magnetization reversal as a function of magnetic field and temperature. These
experiments demonstrate that the crossover occurs in a narrow (~0.1 K) or broad
(~1 K) temperature interval depending on the magnitude and direction of the
applied field. For low external fields applied parallel to the easy axis, the
energy levels that dominate the tunneling shift abruptly with temperature. In
the presence of a transverse field and/or large longitudinal field these energy
levels change with temperature more gradually. A comparison of our experimental
results with model calculations of this crossover suggest that there are
additional mechanisms that enhance the tunneling rate of low lying energy
levels and broaden the crossover for small transverse fields.Comment: 5 pages, 5 figure
Enhancement of the helium resonance lines in the solar atmosphere by suprathermal electron excitation II: non-Maxwellian electron distributions
In solar EUV spectra the He I and He II resonance lines show unusual
behaviour and have anomalously high intensities compared with other transition
region lines. The formation of the helium resonance lines is investigated
through extensive non-LTE radiative transfer calculations. The model
atmospheres of Vernazza, Avrett & Loeser are found to provide reasonable
matches to the helium resonance line intensities but significantly
over-estimate the intensities of other transition region lines. New model
atmospheres have been developed from emission measure distributions derived by
Macpherson & Jordan, which are consistent with SOHO observations of transition
region lines other than those of helium. These models fail to reproduce the
observed helium resonance line intensities by significant factors. The
possibility that non-Maxwellian electron distributions in the transition region
might lead to increased collisional excitation rates in the helium lines is
studied. Collisional excitation and ionization rates are re-computed for
distribution functions with power law suprathermal tails which may form by the
transport of fast electrons from high temperature regions. Enhancements of the
helium resonance line intensities are found, but many of the predictions of the
models regarding line ratios are inconsistent with observations. These results
suggest that any such departures from Maxwellian electron distributions are not
responsible for the helium resonance line intensities.Comment: 23 pages, 11 figures, accepted to appear in MNRAS, LaTeX uses mn.st
Recommended from our members
Care planning for consumers on community treatment orders: an integrative literature review
Background
Case management is the established model for care provision in mental health and is delivered within current care philosophies of person-centred and recovery-oriented care. The fact that people with a mental illness may be forced to receive care and treatment in the community poses challenges for clinicians aiming to engage in approaches that promote shared decision-making and self-determination. This review sought to gain an in-depth understanding of stakeholders’ perspectives and experiences of care planning for consumers’ on CTOs.
Methods
An integrative review method allowed for inclusion of a broad range of studies from diverse empirical sources. Systematic searches were conducted across six databases. Following appraisal, findings from included papers were coded into groups and presented against a framework of case management.
Results
Forty-eight papers were included in the review. Empirical studies came from seven countries, with the majority reporting on qualitative methods. Many similarities were reported across studies. Positive gains from CTOs were usually associated with the nature of support received, highlighting the importance of the therapeutic relationship in care planning. Key gaps in care planning included a lack of connection between CTO, treatment and consumer goals and lack of implementation of focussed interventions.
Conclusions
Current case management processes could be better utilised for consumers on CTOs, with exploration of how this could be achieved warranted. Workers need to be sensitive to the ‘control and care’ dynamic in the care planning relationship, with person-centred approaches requiring core and advanced practitioner and communication skills, including empathy and trust
Projected heat-related mortality under climate change in the metropolitan area of Skopje
Tracking the Expression of Excitatory and Inhibitory Neurotransmission-Related Proteins and Neuroplasticity Markers after Noise Induced Hearing Loss
Excessive exposure to loud noise can damage the cochlea and create a hearing loss. These pathologies coincide with a range of CNS changes including reorganisation of frequency representation, alterations in the pattern of spontaneous activity and changed expression of excitatory and inhibitory neurotransmitters. Moreover, damage to the cochlea is often accompanied by acoustic disorders such as hyperacusis and tinnitus, suggesting that one or more of these neuronal changes may be involved in these disorders, although the mechanisms remain unknown. We tested the hypothesis that excessive noise exposure increases expression of markers of excitation and plasticity, and decreases expression of inhibitory markers over a 32-day recovery period. Adult rats (n = 25) were monaurally exposed to a loud noise (16 kHz, 1/10th octave band pass (115 dB SPL)) for 1-hour, or left as non-exposed controls (n = 5). Animals were euthanased at either 0, 4, 8, 16 or 32 days following acoustic trauma. We used Western Blots to quantify protein levels of GABAA receptor subunit α1 (GABAAα1), Glutamic-Acid Decarboxylase-67 (GAD-67), N-Methyl-D-Aspartate receptor subunit 2A (NR2A), Calbindin (Calb1) and Growth Associated Protein 43 (GAP-43) in the Auditory Cortex (AC), Inferior Colliculus (IC) and Dorsal Cochlear Nucleus (DCN). Compared to sham-exposed controls, noise-exposed animals had significantly (p<0.05): lower levels of GABAAα1 in the contralateral AC at day-16 and day-32, lower levels of GAD-67 in the ipsilateral DCN at day-4, lower levels of Calb1 in the ipsilateral DCN at day-0, lower levels of GABAAα1 in the ipsilateral AC at day-4 and day-32. GAP-43 was reduced in the ipsilateral AC for the duration of the experiment. These complex fluctuations in protein expression suggests that for at least a month following acoustic trauma the auditory system is adapting to a new pattern of sensory input
- …