3,501 research outputs found
Compression Drying of Sapwood
A compression drying experiment carried out on small blocks of sapwood from Pinus radiata, Araucaria cunninghamii. Eucalyptus regnans, and E. obliqua is described. Effects of initial moisture content, speed of compression, specimen thickness and orientation on moisture loss and energy input were studied. All specimens were compressed perpendicular to the grain to the same stress in either a radial or tangential direction in a jig that prevented lateral expansion. Force and deformation changes of the specimens were recorded during compression, and water loss at the end of the process was measured. From these data, volumetric compressions, moisture losses, energy inputs, and energy efficiencies of water removal were calculated.The analyses of variance confirmed that initial moisture content, species and wood specific gravity, amount of volumetric strain, rate of compression, and specimen orientation all affected unit water removal; specimen thickness did not. The lower density softwoods deformed to a greater extent than the hardwoods and lost more water. More water was removed from wetter specimens than drier ones at the same stress, and a slow compression rate caused a greater water loss than a more rapid rate. Specimens compressed tangentially lost more water than those compressed radially. Energy efficiency of water removal was greatest in the relatively low specific gravity Pinus radiata specimens with high moisture contents which were compressed tangentially at a slow rate
Pilot Sensitivity to Simulator Flight Dynamics Model Formulation for Stall Training
A piloted simulation study was performed in the Cockpit Motion Facility at the National Aeronautics and Space Administration Langley Research Center. The research was motivated by the desire to reduce the commercial transport airplane fatal accident rate due to in-flight loss of control. The purpose of this study, which focused on a generic T-tail transport airplane, was to assess pilot sensitivity to flight dynamics model formulation used during a simulator stall recognition and recovery training/demonstration profile. To accomplish this, the flight dynamics model was designed with many configuration options. The model options were based on recently acquired static and dynamic stability and control data from sources that included wind tunnel, water tunnel, and computational fluid dynamics. The results, which are specific to a transport airplane stall recognition and recovery guided demonstration scenario, showed the two most important aerodynamic effects (other than stick pusher) to model were stall roll- off and the longitudinal static stability characteristic associated with the pitch break
Conformal Invariance and Electrodynamics: Applications and General Formalism
The role of the conformal group in electrodynamics in four space-time
dimensions is re-examined. As a pedagogic example we use the application of
conformal transformations to find the electromagnetic field for a charged
particle moving with a constant relativistic acceleration from the Coulomb
electric field for the particle at rest. We also re-consider the reformulation
of Maxwell's equations on the projective cone, which is isomorphic to a
conformal compactification on Minkowski space, so that conformal
transformations, belonging to the group O(4,2), are realised linearly. The
resulting equations are different from those postulated previously and respect
additional gauge invariances which play an essential role in ensuring
consistency with conventional electrodynamics on Minkowski space. The solution
on the projective cone corresponding to a constantly accelerating charged
particle is discussed.Comment: 24 pages, 1 figure, plain tex, uses harvmac, eps
Survival disparities in Indigenous and non-Indigenous New Zealanders with colon cancer: the role of patient comorbidity, treatment and health service factors
Background Ethnic disparities in cancer survival have been documented in many populations and cancer types. The causes of these inequalities are not well understood but may include disease and patient characteristics, treatment differences and health service factors. Survival was compared in a cohort of Maori ( Indigenous) and non-Maori New Zealanders with colon cancer, and the contribution of demographics, disease characteristics, patient comorbidity, treatment and healthcare factors to survival disparities was assessed. Methods Maori patients diagnosed as having colon cancer between 1996 and 2003 were identified from the New Zealand Cancer Registry and compared with a randomly selected sample of non-Maori patients. Clinical and outcome data were obtained from medical records, pathology reports and the national mortality database. Cancer-specific survival was examined using Kaplane-Meier survival curves and Cox hazards modelling with multivariable adjustment. Results 301 Maori and 328 non-Maori patients with colon cancer were compared. Maori had a significantly poorer cancer survival than non-Maori ( hazard ratio (HR) 1.33, 95% CI 1.03 to 1.71) that was not explained by demographic or disease characteristics. The most important factors contributing to poorer survival in Maori were patient comorbidity and markers of healthcare access, each of which accounted for around a third of the survival disparity. The final model accounted for almost all the survival disparity between Maori and non-Maori patients ( HR 1.07, 95% CI 0.77 to 1.47). Conclusion Higher patient comorbidity and poorer access and quality of cancer care are both important explanations for worse survival in Maori compared with non-Maori New Zealanders with colon cancer
Physical characterisation of southern massive star-forming regions using Parkes NH observations
We have undertaken a Parkes ammonia spectral line study, in the lowest two
inversion transitions, of southern massive star formation regions, including
young massive candidate protostars, with the aim of characterising the earliest
stages of massive star formation. 138 sources from the submillimetre continuum
emission studies of Hill et al., were found to have robust (1,1) detections,
including two sources with two velocity components, and 102 in the (2,2)
transition.
We determine the ammonia line properties of the sources: linewidth, flux
density, kinetic temperature, NH column density and opacity, and revisit
our SED modelling procedure to derive the mass for 52 of the sources. By
combining the continuum emission information with ammonia observations we
substantially constrain the physical properties of the high-mass clumps. There
is clear complementarity between ammonia and continuum observations for
derivations of physical parameters.
The MM-only class, identified in the continuum studies of Hill et al.,
display smaller sizes, mass and velocity dispersion and/or turbulence than
star-forming clumps, suggesting a quiescent prestellar stage and/or the
formation of less massive stars.Comment: 20 pages, 9 Figures, 1 appendix (to appear in full online only, a
sample appendix in the paper); 7 tables. Accepted by MNRA
Moving from Trust to Trustworthiness: Experiences of public engagement in the Scottish Health Informatics Programme
The Scottish Health Informatics Programme (SHIP) was a Scotland-wide research programme exploring ways of collecting, managing and analysing electronic patient records for health research. As part of the SHIP public engagement work stream, a series of eight focus groups and a stakeholder workshop were conducted to explore perceptions of the role, relevance and functions of trust (or trustworthiness) in relation to research practices. The findings demonstrate that the public’s relationships of trust and/or mistrust in science and research are not straightforward. This paper aims to move beyond simple descriptions of whether publics trust researchers, or in whom members of the public place their trust, and to explore more fully the bases of public trust/mistrust in science, what trust implies and equally what it means for research/researchers to be trustworthy. This has important implications for public engagement in interdisciplinary projects
Elite male Flat jockeys display lower bone density and lower resting metabolic rate than their female counterparts: implications for athlete welfare
To test the hypothesis that daily weight-making is more problematic to health in male compared with female jockeys, we compared the bone-density and resting metabolic rate (RMR) in weight-matched male and female Flat-jockeys. RMR (kcal.kg-1 lean mass) was lower in males compared with females as well as lower bone-density Z-scores at the hip and lumbar spine. Data suggest the lifestyle of male jockeys’ compromise health more severely than females, possibly due to making-weight more frequently
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