617 research outputs found
Measurement of turbulence spectra using scanning pulsed wind lidars
Turbulent velocity spectra, as measured by a scanning pulsed wind lidar (WindCube), are analyzed. The relationship between ordinary velocity spectra and lidar derived spectra is mathematically very complex, and deployment of the three-dimensional spectral velocity tensor is necessary. The resulting scanning lidar spectra depend on beam angles, line-of-sight averaging, sampling rate, and the full three-dimensional structure of the turbulence being measured, in a convoluted way. The model captures the attenuation and redistribution of the spectral energy at high and low wave numbers very well. The model and measured spectra are in good agreement at two analyzed heights for the u and w components of the velocity field. An interference phenomenon is observed, both in the model and the measurements, when the diameter of the scanning circle divided by the mean wind speed is a multiple of the time between the beam measurements. For the v spectrum, the model and the measurements agree well at both heights, except at very low wave numbers, k1 < 0.005 m?1. In this region, where the spectral tensor model has not been verified, the model overestimates the spectral energy measured by the lidar. The theoretical understanding of the shape of turbulent velocity spectra measured by scanning pulsed wind lidar is given a firm foundation.Aerodynamics, Wind Energy, Flight Performance and PropulsionAerospace Engineerin
Art therapy for PTSD and TBI: A senior active duty military service member’s therapeutic journey
AbstractArt therapy is increasingly being accepted as a form of complementary and integrative care for military veterans affected by trauma and injuries in the line of duty. Less is known, however, about the applications of art therapy for co-morbid traumatic brain injury (TBI) and post-traumatic stress disorder (PTSD). In addition, most studies to date have focused on art therapy with veterans (former military service members) rather than with active duty service members; furthermore, there are no studies that have examined the unique context of PTSD in senior military personnel. This case study presents the therapeutic process through art therapy in the case of a senior active duty military service member (with chronic PTSD and TBI), in the context of an integrated model of care that included medical and complementary therapies
PROPERTIES ANALYSIS OF WASTE PLASTIC OIL AND SIZE MEASUREMENT OF NANO PARTICLE (ALUMINIUM OXIDE)
Environment concerns and depletion of petroleum fuels have created a need for the search fuels for internal combustion engines. Transformation of waste to energy is one of the recent trends in minimizing not only the waste disposal but also could be used as another fuel for internal combustion engines. Plastics are vitally necessary materials in the modern world and application in the industrial field is continually increasing. In this context, waste plastic are currently receiving renewed interest. As an alternative, non-biodegradable, and renewable fuel, waste plastic oil its receiving increasing attention. In this work we choose plastic oil as alternate fuel its properties which relates almost same to diesel. So plastic oil is used as an alternate fuel for direct injection diesel engine
Transition phenomena in unstably stratified turbulent flows
We study experimentally and theoretically transition phenomena caused by the
external forcing from Rayleigh-Benard convection with the large-scale
circulation (LSC) to the limiting regime of unstably stratified turbulent flow
without LSC whereby the temperature field behaves like a passive scalar. In the
experiments we use the Rayleigh-B\'enard apparatus with an additional source of
turbulence produced by two oscillating grids located nearby the side walls of
the chamber. When the frequency of the grid oscillations is larger than 2 Hz,
the large-scale circulation (LSC) in turbulent convection is destroyed, and the
destruction of the LSC is accompanied by a strong change of the mean
temperature distribution. However, in all regimes of the unstably stratified
turbulent flow the ratio varies slightly (even in the range
of parameters whereby the behaviour of the temperature field is different from
that of the passive scalar). Here are the integral scales of
turbulence along x, y, z directions, T and \theta are the mean and fluctuating
parts of the fluid temperature. At all frequencies of the grid oscillations we
have detected the long-term nonlinear oscillations of the mean temperature. The
theoretical predictions based on the budget equations for turbulent kinetic
energy, turbulent temperature fluctuations and turbulent heat flux, are in
agreement with the experimental results.Comment: 14 pages, 14 figures, REVTEX4-1, revised versio
Active-duty military service members’ visual representations of PTSD and TBI in masks
Active-dutymilitary service members have a significant risk of sustaining physical and psychological trauma resulting in traumatic brain injury (TBI) and post-traumatic stress disorder (PTSD). Within an interdisciplinary treatment approach at the National Intrepid Center of Excellence, servicemembers participated in mask making during art therapy sessions. This study presents an analysis of the mask-making experiences of service members (n = 370) with persistent symptoms from combatand mission-related TBI, PTSD, and other concurrent mood issues. Data sources included mask images and therapist notes collected over a five-year period. The data were coded and analyzed using grounded theory methods. Findings indicated that mask making offered visual representations of the self related to individual personhood, relationships, community, and society. Imagery themes referenced the injury, relational supports/losses, identity transitions/questions, cultural metaphors, existential reflections, and conflicted sense of self. These visual insights provided an increased understanding of the experiences of service members, facilitating their recovery
GenomeTrafac: a whole genome resource for the detection of transcription factor binding site clusters associated with conventional and microRNA encoding genes conserved between mouse and human gene orthologs
Transcriptional cis-regulatory control regions frequently are found within non-coding DNA segments conserved across multi-species gene orthologs. Adopting a systematic gene-centric pipeline approach, we report here the development of a web-accessible database resource—GenomeTraFac ()—that allows genome-wide detection and characterization of compositionally similar cis-clusters that occur in gene orthologs between any two genomes for both microRNA genes as well as conventional RNA-encoding genes. Each ortholog gene pair can be scanned to visualize overall conserved sequence regions, and within these, the relative density of conserved cis-element motif clusters form graph peak structures. The results of these analyses can be mined en masse to identify most frequently represented cis-motifs in a list of genes. The system also provides a method for rapid evaluation and visualization of gene model-consistency between orthologs, and facilitates consideration of the potential impact of sequence variation in conserved non-coding regions to impact complex cis-element structures. Using the mouse and human genomes via the NCBI Reference Sequence database and the Sanger Institute miRBase, the system demonstrated the ability to identify validated transcription factor targets within promoter and distal genomic regulatory regions of both conventional and microRNA genes
Direct estimation of the Reynolds stress vertical structure in the nearshore
Author Posting. © American Meteorological Society, 2007. This article is posted here by permission of American Meteorological Society for personal use, not for redistribution. The definitive version was published in Journal of Atmospheric and Oceanic Technology 24 (2007): 102-116, doi:10.1175/JTECH1953.1.Measurements of the vertical Reynolds stress components in the wave-dominated nearshore are required to diagnose momentum and turbulence dynamics. Removing wave bias from Reynolds stress estimates is critical to a successful diagnosis. Here two existing Reynolds stress estimation methods (those of Trowbridge, and Shaw and Trowbridge) for wave-dominated environments and an extended method (FW) that is a combination of the two are tested with a vertical array of three current meters deployed in 3.2-m water depth off an ocean beach. During the 175-h-long experiment the instruments were seaward of the surfzone and the alongshore current was wind driven. Intercomparison of Reynolds stress methods reveals that the Trowbridge method is wave bias dominated. Tests of the integrated cospectra are used to reject bad Reynolds stress estimates, and the Shaw and Trowbridge estimates are rejected more often than FW estimates. With the FW method, wave bias remains apparent in the cross-shore component of the Reynolds stress. However, the alongshore component of Reynolds stress measured at the three current meters are related to each other with a vertically uniform first EOF containing 73% of the variance, indicating the presence of a constant stress layer. This is the first time the vertical structure of Reynolds stress has been measured in a wave-dominated environment. The Reynolds stress is, albeit weakly, related to the wind stress and a parameterized bottom stress. Using derived wave bias and bottom stress parameterizations, the effect of wave bias on Reynolds stress estimates is shown to be weaker for more typical surfzone conditions (with both stronger waves and currents than those observed here).Funded by NSF, ONR, and
NOPP
Correction of a Non-orthogonal, Three-Component Sonic Anemometer for Flow Distortion by Transducer Shadowing
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Turbulent flow at 190 m height above London during 2006-2008: A climatology and the applicability of similarity theory
Flow and turbulence above urban terrain is more complex than above rural terrain, due to the different momentum and heat transfer characteristics that are affected by the presence of buildings (e.g. pressure variations around buildings). The applicability of similarity theory (as developed over rural terrain) is tested using observations of flow from a sonic anemometer located at 190.3 m height in London, U.K. using about 6500 h of data. Turbulence statistics—dimensionless wind speed and temperature, standard deviations and correlation coefficients for momentum and heat transfer—were analysed in three ways. First, turbulence statistics were plotted as a function only of a local stability parameter z/Λ (where Λ is the local Obukhov length and z is the height above ground); the σ_i/u_* values (i = u, v, w) for neutral conditions are 2.3, 1.85 and 1.35 respectively, similar to canonical values. Second, analysis of urban mixed-layer formulations during daytime convective conditions over London was undertaken, showing that atmospheric turbulence at high altitude over large cities might not behave dissimilarly from that over rural terrain. Third, correlation coefficients for heat and momentum were analyzed with respect to local stability. The results give confidence in using the framework of local similarity for turbulence measured over London, and perhaps other cities. However, the following caveats for our data are worth noting: (i) the terrain is reasonably flat, (ii) building heights vary little over a large area, and (iii) the sensor height is above the mean roughness sublayer depth
Tracking momentary experience in the evaluation of arts-on-prescription services: Using mood changes during art workshops to predict global wellbeing change
Aims: To measure the immediate impact of participating in arts-on-prescription workshops on multiple dimensions of mood and to evaluate whether improvement in mood is a mechanism for change, predicting improvements in global wellbeing before and after participation in arts-on-prescription programmes. Methods: The evaluation drew upon the experience sampling method, asking participants to complete a six-item mood questionnaire at the beginning and end of each workshop in a 12-week-long arts-on-prescription programme. Participants also completed a measure of global wellbeing at the beginning and end of the programme. Results: Multilevel modelling was used to test hypotheses since the data were hierarchical (with 1491 mood reports nested within 66 participants). There was a significant improvement in global wellbeing across participation in the arts-on-prescription programme. After each art workshop there was a significant increase on all dimensions of mood: hedonic tone (contentment); tense arousal (calmness); and energetic arousal (alertness). There was also a significant improvement in these dimensions of mood, over time, upon arrival at the art workshops each week. Furthermore, reduction in tense arousal after art workshops significantly predicted changes in global wellbeing. Conclusion: The findings suggest that a reduction in tense arousal (feeling less nervous, anxious and stressed) is a crucial component of arts-on-prescription services and make a direct link between experiences during art workshops and changes in global wellbeing for the first time. This strengthens the evidence base for arts-on-prescription and suggests that tracking experience across interventions is a useful evaluation tool, with much potential
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