208 research outputs found

    Manned Mars mission vehicle design requirements for aerocapture

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    Vehicle design requirements of a reusable system for manned Mars missions which employ aerocapturing techniques to obtain desired orbital velocities are defined. Requirements for vehicle L/D and ballistic coefficient are determined for expected aerocapture velocities. Conclusions are presented concerning g-loads environment and TPS requirements for a vehicle that aerocaptures at Mars and Earth. Although the goal of a reusable system (based on current state-of-art technologies) was not obtained, the viability of aerocapture at Mars and Earth was established

    Trees

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    The student will be able to locate, identify, and understand the photosynthic cycle of 6 species of trees. The student will also be able to explain physical observations made of each tree

    Opaque Markets and Rapid Growth: the Superiority of Bank-Centered Financial Systems for Developing Nations

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    This paper analyzes the relationship between private investment incentives and the speed at which information regarding investment becomes public. In a developed country context, public information plays a limited role in creating investment incentives. However, in an environment of rapid economic development, firms only have a strong incentive to invest if information only becomes public after a long lag. Thus, the public disclosure that is an integral part of effective stock markets inhibits investment in developing countries despite not being problematic in developed nations. On the other hand, bank-centered financial systems limit the amount of public information and are therefore better suited to developing countries.

    Near term mitigation policy for global change under uncertainty: Minimizing the expected cost of meeting unknown concentration thresholds

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    An aggregate integrated assessment model is used to investigate the relative merits of hedging over the near term against the chance that atmospheric concentrations of carbon dioxide will be limited as a matter of global policy. Hedging strategies are evaluated given near term uncertainty about the targeted level of limited concentrations and the trajectory of future carbon emissions. All uncertainty is resolved in the year 2020, and strategies that minimize the expected discounted value of the long term cost of abatement, including the extra cost of adjusting downstream to meet unexpected concentration limits along unanticipated emission trajectories, are identified. Even with uncertainties that span current wisdom on emission futures and restriction thresholds that run from 550 ppm through 850 ppm, the results offer support for at most modest abatement response over the next several decades to the threat of global change.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/42705/1/10666_2005_Article_BF01874846.pd

    Authentication Based on Periocular Biometrics and Skin Tone

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    Face images with masks have a major effect on the identification and authentication of people with masks covering key facial features such as noses and mouths. In this paper, we propose to use periocular region and skin tone for authenticating users with masked faces. We first extract the periocular region of faces with masks, then detect the skin tone for each face. We then train models using machine learning algorithms Random Forest, XGBoost, and Decision Trees using skin tone information and perform classification on two datasets. Experiment results show these models had good performance

    Carbon-assisted chemical vapor deposition of hexagonal boron nitride

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    We show that in a low-pressure chemical vapor deposition (CVD) system, the residual oxygen and/or air play a crucial role in the mechanism of the growth of hexagonal boron nitride (h-BN) films on Ni foil 'enclosures'. Hexagonal-BN films grow on the Ni foil surface via the formation of an intermediate boric-oxide (BOx) phase followed by a thermal reduction of the BOx by a carbon source (either amorphous carbon powder or methane), leading to the formation of single-and bi-layer h-N. Low energy electron microscopy (LEEM) and diffraction (LEED) were used to map the number of layers over large areas; Raman spectroscopy, time-of-flight secondary ion mass spectrometry (ToF-SIMS), x-ray photoelectron spectroscopy (XPS) and scanning tunneling microscopy (STM) were used to characterize the structure and physical quality of the ultra-thin h-BN film. The growth procedure reported here leads to a better understanding and control of the synthesis of ultra-thin h-BN films

    Serotype Diversity of Respiratory Human Adenoviruses amongst Pediatric Patients from Western Kenya, 2010-2012

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    Background: Respiratory illnesses are common among pediatric patients in Kenya, and many are attributed to viral causes. However, there is limited knowledge of the diversity of viral etiologies associated with these illnesses. Objective: To characterize respiratory adenoviruses isolates using serological and molecular approaches. Methods: A total of 1,879 samples were collected from symptomatic pediatric patients seeking medical care at New Nyanza Provincial General Hospital during the period of June 2010 to June 2012 and screened for adenoviruses as well as other respiratory viruses. Sixteen respiratory human adenoviruses (HAdVs) were isolated in Hep2 cell culture and characterized them using Immunofluorescence Assay, viral DNA amplification, sequencing and phylogenomics. Results: Phylogenetic characterization of the HAdVs using the hyper variable region 7 of the hexon gene identified HAdV B and C as the major species associated with respiratory infections during the study period. Amongst these, a single B-type and four C-type serotypes were identified.  The serotype distribution consisted of 31% HAdV B7, 25% HAdV C1, 25% HAdV C2, 6% HAdV C5, and 13% HAdV C6. Positive selection was observed in the nucleotide sequences from HAdV B7 and HAdV C5 signaling evolution of these two serotypes. Conclusion: These finding may be useful to policy makers regarding appropriate strain selection for vaccination in Kenya. Keywords: Respiratory Human adenovirus, Kenya, Pediatric, Serotype, Hexon, HVR-
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