3,748 research outputs found

    The North Carolina A and T State University Student Space Shuttle Program

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    Inspired into being in 1979 by the late astronaut, Dr. Ronald McNair, the primary goal of this student centered program is to perform two experiments, Arthopod Development Study and Crystal Growth Study. Since 1979, 78 different students representing 12 majors have participated in every phase of development of the payload -- from coming up with the original ideas to final fabrication and testing. Students have also been involved in many extra activities such as presenting their results at annual meetings and hosting tours of our lab for local schools. The program has received extensive outside support in the form of funds, technical assistance and donated parts. The payload, made primarily out of aluminum, consists of a central column structure, a battery box, a crystal growth box, an arthropod development box, four control circuit boxes, and a thermograph box. The battery box contains 24, Eveready 6V, Alkaline batteries. The thermograph box contains 3 Ryan TempMentors. Fabrication of the payload is essentially complete and a complete testing program has been initiated

    Quasi-phasematching of harmonic generation via multimode beating in waveguides

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    A new scheme for quasi-phasematching high harmonic generation (HHG) in gases is proposed. In this, the rapid variation of the axial intensity resulting from excitation of more than one mode of a waveguide is used to achieve quasi phasematching. Numerical modeling demonstrates enhancement of the harmonic signal over that achieved for a single coherence length by factors >10^4.Comment: 6 pages including 3 figure

    Vengeance is Ours: Safe Spaces and Critical Empathy in Horror Films

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    Many genres of film seek to bring viewers to heightened emotional states, perhaps this is most true of horror films. Although often displaying extreme violence, such films paradoxically provide openings for critically empathetic viewings which allow viewers with diverse backgrounds and experiences to identify with victims and survivors and transcend elements of subjective identity. This project analyzes the capacity of horror films, including those of William Friedkin, David Cronenberg, Brian DePalma and others, to offer viewers space in which to be critically empathetic. Regarding gender issues in the genre as outlined by such scholars as Carol J. Clover, and the emerging scholarship on critical empathy, such as that of Todd DeStigter, this project offers new ways of thinking about horror both on screen and off

    Multi-Pulse Laser Wakefield Acceleration: A New Route to Efficient, High-Repetition-Rate Plasma Accelerators and High Flux Radiation Sources

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    Laser-driven plasma accelerators can generate accelerating gradients three orders of magnitude larger than radio-frequency accelerators and have achieved beam energies above 1 GeV in centimetre long stages. However, the pulse repetition rate and wall-plug efficiency of plasma accelerators is limited by the driving laser to less than approximately 1 Hz and 0.1% respectively. Here we investigate the prospects for exciting the plasma wave with trains of low-energy laser pulses rather than a single high-energy pulse. Resonantly exciting the wakefield in this way would enable the use of different technologies, such as fibre or thin-disc lasers, which are able to operate at multi-kilohertz pulse repetition rates and with wall-plug efficiencies two orders of magnitude higher than current laser systems. We outline the parameters of efficient, GeV-scale, 10-kHz plasma accelerators and show that they could drive compact X-ray sources with average photon fluxes comparable to those of third-generation light source but with significantly improved temporal resolution. Likewise FEL operation could be driven with comparable peak power but with significantly larger repetition rates than extant FELs

    Combined visible and near-infrared OPA for wavelength scaling experiments in strong-field physics

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    We report the operation of an optical parametric amplifier (OPA) capable of producing gigawatt peak-power laser pulses with tunable wavelength in either the visible or near-infrared spectrum. The OPA has two distinct operation modes (i) generation of >350 uJ, sub 100 fs pulses, tunable between 1250 - 1550 nm; (ii) generation of >190 uJ, sub 150 fs pulses tunable between 490 - 530 nm. We have recorded high-order harmonic spectra over a wide range of driving wavelengths. This flexible source of femtosecond pulses presents a useful tool for exploring the wavelength-dependence of strong-field phenomena, in both the multi-photon and tunnel ionization regimes.Comment: 14 pages, 9 figures, This paper was published in Proceedings of SPIE 10088, Nonlinear Frequency Generation and Conversion: Materials and Devices XVI, doi 10.1117/12.225077

    Discrete-choice modelling of patient preferences for modes of drug administration.

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    The administration of (biologically-derived) drugs for various disease conditions involves consumption of resources that constitutes a direct monetary cost to healthcare payers and providers. An often ignored cost relates to a mismatch between patients' preferences and the mode of drug administration. The "intangible" benefits of giving patients what they want in terms of the mode of drug delivery is seldom considered. This study aims to evaluate, in monetary terms, end-user preferences for the non-monetary attributes of different modes of drug administration using a discrete-choice experiment. It provides empirical support to the notion that there are significant benefits from developing patient-friendly approaches to drug delivery. The gross benefits per patient per unit administration is in the same order of magnitude as the savings in resource costs of administering drugs. The study argues that, as long as the underlying manufacturing science is capable, a patient-centred approach to producing drug delivery systems should be encouraged and pursued

    Challenges of developing decision-support LCA tools in the biopharmaceutical industry

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    The biopharmaceutical industry has been slow in carrying out LCA analyses. However, as the industry matures, the level of scrutiny placed on this industry by international governments will increase and hence, there is an urgent need for the industry to implement decision-support tools for the decision-making processes. Decision-support tools based on life cycle assessment (LCA) can be potentially used for application in the biopharmaceutical industry as an aid to decision making. This paper sets out the challenges associated with developing such decision-support LCA tools. This paper highlights that in order for the industry to overcome these challenges and successfully develop decision-support LCA tools, they require a broader understanding of the biopharmaceutical manufacturing processes and LCA methodology

    A l% and 1cm Perspective Leads to a Novel CDOM Absorption Algorithm

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    A next-generation in-water profiler designed to measure the apparent optical properties of seawater was developed and validated across a wide dynamic range of water properties. This new Compact-Optical Profiling System (C-OPS) design uses a novel, kite-shaped, free-falling backplane with adjustable buoyancy and is based on 19 state-of-the-art microradiometers, spanning 320-780 nm. Data collected as part of the field commissioning were of a previously unachievable quality and showed that systematic uncertainties in the sampling protocols were discernible at the 1% optical and 1cm depth resolution levels. A sensitivity analysis as a function of three water types, established by the peak in the remote sensing reflectance spectra, revealed which water types and spectral domains were the most indicative of data acquisition uncertainties. The unprecedented vertical resolution of C-OPS measurements provided near-surface data products at the spectral endpoints with a quality level that has not been obtainable. The improved data allowed development of an algorithm for predicting the spectral absorption due to chromophoric dissolved organic matter (CDOM) using ratios of diffuse attenuation coefficients with over 99% of the variance in the data explained
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