2,118 research outputs found
A hypersonic research vehicle to develop scramjet engines
Four student design teams produced conceptual designs for a research vehicle to develop the supersonic combustion ramjet (scramjet) engines necessary for efficient hypersonic flight. This research aircraft would provide flight test data for prototype scramjets that is not available in groundbased test facilities. The design specifications call for a research aircraft to be launched from a carrier aircraft at 40,000 feet and a Mach number of 0.8. The aircraft must accelerate to Mach 6 while climbing to a 100,000 foot altitude and then ignite the experimental scramjet engines for acceleration to Mach 10. The research vehicle must then be recovered for another flight. The students responded with four different designs, two piloted waverider configurations, and two unmanned vehicles, one with a blended body-wing configuration, the other with a delta wing shape. All aircraft made use of an engine database provided by the General Electric Aircraft Engine Group; both turbofan ramjet and scramjet engine performance using liquid hydrogen fuel was available. Explained here are the students' conceptual designs and the aerodynamic and propulsion concepts that made their designs feasible
Effectiveness of an AIDS and universal infection control precautions program for certified nursing assistants
Noble internal transport barriers and radial subdiffusion of toroidal magnetic lines
Single trajectories of magnetic line motion indicate the persistence of a
central protected plasma core, surrounded by a chaotic shell enclosed in a
double-sided transport barrier : the latter is identified as being composed of
two Cantori located on two successive "most-noble" numbers values of the
perturbed safety factor, and forming an internal transport barrier (ITB).
Magnetic lines which succeed to escape across this barrier begin to wander in a
wide chaotic sea extending up to a very robust barrier (as long as L<1) which
is identified mathematically as a robust KAM surface at the plasma edge. In
this case the motion is shown to be intermittent, with long stages of
pseudo-trapping in the chaotic shell, or of sticking around island remnants, as
expected for a continuous time random walk.Comment: TEX file, 84 pages including 32 color figures. Higher quality figures
can be seen on the PDF file at
http://membres.lycos.fr/fusionbfr/JHM/Tokamap/JSP.pd
Focusing a fountain of neutral cesium atoms with an electrostatic lens triplet
An electrostatic lens with three focusing elements in an alternating-gradient
configuration is used to focus a fountain of cesium atoms in their ground
(strong-field-seeking) state. The lens electrodes are shaped to produce only
sextupole plus dipole equipotentials which avoids adding the unnecessary
nonlinear forces present in cylindrical lenses. Defocusing between lenses is
greatly reduced by having all of the main electric fields point in the same
direction and be of nearly equal magnitude. The addition of the third lens gave
us better control of the focusing strength in the two transverse planes and
allowed focusing of the beam to half the image size in both planes. The beam
envelope was calculated for lens voltages selected to produced specific
focusing properties. The calculations, starting from first principles, were
compared with measured beam sizes and found to be in good agreement.
Application to fountain experiments, atomic clocks, and focusing polar
molecules in strong-field-seeking states is discussed.Comment: 8 pages 10 figure
Cell Size and Morphological Properties of Yeast Saccharomyces Cerevisiae in Relation to Growth Temperature
Cell volume is an important parameter for modelling cellular processes. Temperature-induced variability of cellular size, volume, intracellular granularity, a fraction of budding cells of yeast Saccharomyces cerevisiae CEN.PK 113–7D (in anaerobic glucose unlimited batch cultures) were measured by flow cytometry and matched with the performance of the biomass growth (maximal specific growth rate (μmax), specific rate of glucose consumption, the rate of maintenance, biomass yield on glucose). The critical diameter of single cells was 7.94 μm and it is invariant at growth temperatures above 18.5◦C. Below 18.5◦C, it exponentially increases up to 10.2 μm. The size of the bud linearly depends on μmax, and it is between 50% at 5◦C and 90% at 31◦C of the averaged single cell. The intracellular granularity (side scatter channel (SSC)-index) negatively depends on μmax. There are two temperature regions (5–31◦C vs. 33–40◦C) where the relationship between SSC-index and various cellular parameters differ significantly. In supraoptimal temperature range (33–40◦C), cells are less granulated perhaps due to a higher rate of the maintenance. There is temperature dependent passage through the checkpoints in the cell cycle which influences the μmax. The results point to the existence of two different morphological states of yeasts in these different temperature regions. © FEMS 2018. All rights reserved.The experimental part of the research has been carried out in Institute of Biochemical Engineering (IBVT, University of Stuttgart, Germany) and has been funded by the transnational research initiative ‘Systems Biology of Microorganisms (SysMO)’ within network MOSES: ‘MicroOrganism Systems Biology: Energy and Saccharomyces cerevisiae’ [http://www.sysmo.net]. Additionally, the author would like to thank Prof.Peter Scheurich (Institute of Cell Biology and Immunology, University of Stuttgart, Germany) for the experimental support, Achim Hauck (IBVT, University of Stuttgart, Germany) and Dr.Xuelian Yang (Beijing Engineering and Technology Research Center of Food Additives, Beijing Technology & Business University, Beijing, China) for the research assistance, Dr.Pavlo Holenya (Institute of Pharmacy and Molecular Biotechnology, University of Heidelberg, Germany) for the discussion of the results
High‐gain lateral pnp bipolar transistors made using focused ion beam implantation
We report the fabrication of lateral pnp bipolar transistors using focused ion beam (FIB) implants of boron and phosphorus for the collector and base, respectively. The implants of B+, P+, and P+ + were all at a dose of 1×1013 /cm2 and a beam voltage of 75 kV. These implants defined spaces between the emitter and collector regions of 0.5–1.50 μm; which, after diffusion and zero voltage depletion width effects were considered, produced effective on‐wafer device basewidths of ∼0.2 μm. For the best devices, values of hFE near 100 were obtained with good junction characteristics and at peak collector currents of 10 μA/μm of device width
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3D modelling of angiogenesis and vascular tumour growth
This paper was presented at the 3rd Micro and Nano Flows Conference (MNF2011), which was held at the Makedonia Palace Hotel, Thessaloniki in Greece. The conference was organised by Brunel University and supported by the Italian Union of Thermofluiddynamics, Aristotle University of Thessaloniki, University of Thessaly, IPEM, the Process Intensification Network, the Institution of Mechanical Engineers, the Heat Transfer Society, HEXAG - the Heat Exchange Action Group, and the Energy Institute
Relatedness in Gaming: The Effect in‑Game Touch Has on Player Connection
With the number of individuals becoming gamers on the rise, it has become ever so important to understand the underlying motivations and social interactions that occur within this video game medium. Research has revealed that player motivation and relatedness within a game setting can be affected by the interpersonal relationships that develop from in game social interactions. This specific study was interested in how interpersonal touch and relatedness gestures, more specifically positive or negative touch conditions within a gameplay experience, can impact both player motivations, as well as inter-player impressions. Additionally, observational data measuring the quality of interaction between the participant in the study and a research confederate, with whom they were playing an online game was collected. A positive relationship was found between player relatedness and positive touch between avatars
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