1,019 research outputs found

    THE POLITICAL ECONOMY OF THE U.S.-MEXICO FREE TRADE AGREEMENT: ANALYSIS OF THE CONGRESSIONAL FAST TRACK VOTE

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    This paper presents an empirical analysis of the strategic forces shaping U.S.-Mexico trade relationships and the possibilities of extending the trade agreement to the rest of the Americas. The paper concludes that constituency interests, party loyalty, the proportion of a state's population of Hispanic origin, and the influence of textile-related employment in the state were significant explanatory factors in the Congressional Fast Track vote that occurred in May of 1991.Free trade agreement, Fast track, Textiles, Congressional voting, International Relations/Trade, Political Economy,

    Effect of particle size of Martian dust on the degradation of photovoltaic cell performance

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    Glass coverglass and SiO2 covered and uncovered silicon photovoltaic (PV) cells were subjected to conditions simulating a Mars dust storm, using the Martian Surface Wind Tunnel, to assess the effect of particle size on the performance of PV cells in the Martian environment. The dust used was an artificial mineral of the approximate elemental composition of Martian soil, which was sorted into four different size ranges. Samples were tested both initially clean and initially dusted. The samples were exposed to clear and dust laden winds, wind velocities varying from 23 to 116 m/s, and attack angles from 0 to 90 deg. It was found that transmittance through the coverglass approximates the power produced by a dusty PV cell. Occultation by the dust was found to dominate the performance degradation for wind velocities below 50 m/s, whereas abrasion dominates the degradation at wind velocities above 85 m/s. Occultation is most severe at 0 deg (parallel to the wind), is less pronounced from 22.5 to 67.5 deg, and is somewhat larger at 90 deg (perpendicular to the wind). Abrasion is negligible at 0 deg, and increases to a maximum at 90 deg. Occultation is more of a problem with small particles, whereas large particles (unless they are agglomerates) cause more abrasion

    The chemical effects of the Martian environment on power system component materials: A theoretical approach

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    In the foreseeable future, an expedition may be undertaken to explore the planet Mars. Some of the power source options being considered for such a mission are photovoltaics, regenerative fuel cells and nuclear reactors. In addition to electrical power requirements, environmental conditions en route to Mars, in the planetary orbit and on the Martian surface must be simulated and studied in order to anticipate and solve potential problems. Space power systems components such as photovoltaic arrays, radiators, and solar concentrators may be vulnerable to degradation in the Martian environment. Natural characteristics of Mars which may pose a threat to surface power systems include high velocity winds, dust, ultraviolet radiation, large daily variation in temperature, reaction to components of the soil, atmosphere and atmospheric condensates as well as synergistic combinations. Most of the current knowledge of the characteristics of the Martian atmosphere and soil composition was obtained from the Viking 1 and 2 missions in 1976. A theoretical study is presented which was used to assess the effects of the Martian atmospheric conditions on the power systems components. A computer program written at NASA-Lewis for combustion research that uses a free energy minimization technique was used to calculate chemical equilibrium for assigned thermodynamic states of temperature and pressure. The power system component materials selected for this study include: silicon dioxide, silicon, carbon, copper, and titanium. Combinations of environments and materials considered include: (1) Mars atmosphere with power surface material, (2) Mars atmosphere and dust component with power surface material, and (3) Mars atmosphere and hydrogen peroxide or superoxide or superoxide with power system material. The chemical equilibrium calculations were performed at a composition ratio (oxidant to reactant) of 100. The temperature for the silicon dioxide material and silicon, which simulate photovoltaic cells, were 300 and 400 K; for carbon, copper and titanium, which simulate radiator surfaces, 300, 500, and 1000 K. All of the systems were evaluated at pressures of 700, 800, and 900 Pa, which stimulate the Martian atmosphere

    Aeolian Removal of Dust Types from Photovoltaic Surfaces on Mars

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    Dust elevated in local or global dust storms on the Martian surface could settle on photovoltaic (PV) surfaces and seriously hamper their performance. Using a recently developed technique to apply a uniform dust layer, PV surface materials were subjected to simulated Martian winds in an attempt to determine whether natural aeolian processes on Mars would sweep off the settled dust. Three different types of dust were used. The effects of wind velocity, angle of attack, height above the Martian surface, and surface coating material were investigated. It was found that arrays mounted on an angle of attack approaching 45 deg show the most efficient clearing. Although the angular dependence is not sharp, horizontally mounted arrays required much higher wind velocities to clear off the dust. From this test it appears that the arrays may be erected quite near the ground, but previous studies have suggested that saltation effects can be expected to cause such arrays to be covered by soil if they are set up less than about a meter from the ground. Particle size effect appear to dominate over surface chemistry in these experiments, but additional tests are required to confirm this

    “Getting Freaky”: Perversion and Promiscuity Within Alternative Relationships and Sexual Modalities Among People Of Color

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    This paper explores how people of color, particularly black people in the Atlanta area, navigate inside and outside of their sexual communities – particularly, BDSM, polyamory and swinging communities. I investigated how participants’ (N=11) identity construction and sexual actions/behaviors contributed to the benefits and/or consequences that fostered the navigation of non-sexual and sexual communities using queer theory and intersectionality theory with a womanist approach. Particularly, I found that my participants migrated towards communities based on privilege, comfort, and acts of resistance. In addition, I found that while they all identified as “perverts of color,” they did not identify as “promiscuous.” Overall, this study highlights the potential for people to resist certain oppressions, all while maintaining a sex-positive politic inside and outside of their alternative sexual communities. It also emphasizes the need to broaden our scopes on sexual liberation movements that marginalize those with various intersections of identities
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