35,712 research outputs found
An overview of aeroelasticity studies for the National Aerospace Plane
The National Aero-Space Plane (NASP), or X-30, is a single-stage-to-orbit vehicle that is designed to takeoff and land on conventional runways. Research in aeroelasticity was conducted by NASA and the Wright Laboratory to support the design of a flight vehicle by the national contractor team. This research includes the development of new computational codes for predicting unsteady aerodynamic pressures. In addition, studies were conducted to determine the aerodynamic heating effects on vehicle aeroelasticity and to determine the effects of fuselage flexibility on the stability of the control systems. It also includes the testing of scale models to better understand the aeroelastic behavior of the X-30 and to obtain data for code validation and correlation. This paper presents an overview of the aeroelastic research which has been conducted to support the airframe design
Reframing e-assessment: building professional nursing and academic attributes in a first year nursing course
This paper documents the relationships between pedagogy and e-assessment in two nursing courses offered at the University of Southern Queensland, Australia. The courses are designed to build the academic, numeracy and technological attributes student nurses need if they are to succeed at university and in the nursing profession. The paper first outlines the management systems supporting the two courses and how they intersect with the e-learning and e-assessment components of course design. These pedagogical choices are then reviewed. While there are lessons to be learnt and improvements to be made, preliminary results suggest students and staff are extremely supportive of the courses. The e-assessment is very positively received with students reporting increased confidence and competency in numeracy, as well as IT, academic, research and communication skills
The development and characteristics of a hand-held high power diode laser-based industrial tile grout removal and single-stage sealing system
As the field of laser materials processing becomes ever more diverse, the high power diode laser (HPDL) is now being regarded by many as the most applicable tool. The commercialisation of an industrial epoxy grout removal and single-stage ceramic tile grout sealing process is examined through the development of a hand-held HPDL device in this work. Further, an appraisal of the potential hazards associated with the use of the HPDL in an industrial environment and the solutions implemented to ensure that the system complies with the relevant safety standards are given. The paper describes the characteristics and feasibility of the industrial epoxy grout removal process. A minimum power density of approximately 3 kW/cm2 was found to exist, whilst the minimum interaction time, below which there was no removal of epoxy tile grout, was found to be approximately 0.5 s. The maximum theoretical removal rate that may be achievable was calculated as being 65.98 mm2/s for a circular 2 mm diameter beam with a power density of 3 kW/cm2 and a traverse speed of 42 mm/s. In addition, the characteristics of the single-stage ceramic tile grout sealing are outlined. The single-stage ceramic tile grout sealing process yielded crack and porosity free seals which were produced in normal atmospheric conditions. Tiles were successfully sealed with power densities as low as 550 W/cm2 and at rates of up to 420 mm/min. In terms of mechanical, physical and chemical characteristics, the single-stage ceramic tile grout was found to be far superior to the conventional epoxy tile grout and, in many instances, matched and occasionally surpassed that of the ceramic tiles themselves
Tapered, tubular polyester fabric
A tapered tubular polyester sleeve is described to serve as the flexible foundation for a spacesuit limb covering. The tube has a large end and a small end with a length to be determined. The ratio of taper is also determined by scale factors. All the warp yarns extend to the large end. A requisite number of warp yarns extend the full length of the sleeve. Other warp yarns extend from the large end but are terminated along the length of the sleeve. It is then woven with a filling yarn which extends in a full circle along the full length of the sleeve to thereby define the tapered sleeve. The sleeve after fabrication is then placed on a mandrel, heated in an oven, and then attached to the arm or other limb of the spacesuit
Requirements for in vivo IFN-Îł induction by live microfilariae of the parasitic nematode, Brugia malayi
Exploring the fate of the tris(pentafluorophenyl)borane radical anion in weakly coordinating solvents
Short time-scale optical variability of the dwarf Seyfert nucleus in NGC 4395
We present optical spectroscopic observations of the least-luminous known
Seyfert 1 galaxy, NGC 4395, which was monitored every half-hour over the course
of 3 nights. The continuum emission varied by ~35 per cent over the course of 3
nights, and we find marginal evidence for greater variability in the blue
continuum than the red. A number of diagnostic checks were performed on the
data in order to constrain any systematic or aperture effects. No correlations
were found that adequately explained the observed variability, hence we
conclude that we have observed real intrinsic variability of the nuclear
source. No simultaneous variability was measured in the broad H-beta line,
although given the difficulty in deblending the broad and narrow components it
is difficult to comment on the significance of this result. The observed short
time-scale continuum variability is consistent with NGC 4395 having an
intermediate-mass (~10^5 solar masses) central supermassive black hole, rather
than a very low accretion rate. Comparison with the Seyfert 1 galaxy NGC 5548
shows that the observed variability seems to scale with black hole mass in
roughly the manner expected in accretion models. However the absolute
time-scale of variability differs by several orders of magnitude from that
expected in simple accretion disc models in both cases.Comment: 16 pages, 14 figures, 5 tables, accepted for publication in MNRA
Toxicity of thermal degradation products of spacecraft materials
Three polymeric materials were evaluated for relative toxicity of their pyrolysis products to rats by inhalation: Y-7683 (LS 200), Y-7684 (Vonar 3 on Fiberglass), and Y-7685 (Vonar 3 on N W Polyester). Criteria employed for assessing relative toxicity were (1) lethality from in-chamber pyrolysis, (2) lethality from an outside-of-chamber pyrolysis MSTL Procedure, and (3) disruption of trained rats' shock-avoidance performance during sub-lethal exposures to in-chamber pyrolysis of the materials
THE CONSEQUENCES OF AN OPEN FIELD BURNING BAN ON THE U.S. KENTUCKY BLUEGRASS SEED INDUSTRY
An econometric model of the U.S. Kentucky bluegrass seed industry in the Pacific Northwest is specified and estimated in order to evaluate the short and long run consequences of yield reductions associated with a ban on open field burning of grass residues. While results differ among regions, model simulations of short run effects of reduced yields attributed to the burning ban indicate price increases for grass seed ranging from 0 to 69 percent and long run effects indicate increased acreage of grass seed production due to producers responses to higher prices.Crop Production/Industries,
Single-stage sealing of ceramic tiles by means of high power diode laser radiation
An investigation has been carried out using a 60 W high power diode laser (HPDL) to determine the feasibility of sealing the void between adjoining ceramic tiles with a specially developed grout material. A single-stage process has subsequently been devised using a new grout material which consists of two distinct components: a crushed ceramic tile mix substrate and a glazed enamel surface; the crushed ceramic tile mix provides a tough, inexpensive bulk substrate, whilst the enamel provides an impervious surface glaze. HPDL processing has resulted in crack and porosity free seals produced in normal atmospheric conditions. The single-stage grout is simple to formulate and easy to apply. Tiles were successfully sealed with power densities as low as 750 W/cm2 and at rates of up to 420 mm/min. Bonding of the enamel to the crushed ceramic tile mix was identified as being primarily due to van der Waals forces and, on a very small scale, some of the crushed ceramic tile mix material dissolving into the glaze
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