3,645 research outputs found
Literature survey of properties of synfuels derived from coal
A literature survey of the properties of synfuels for ground-based gas turbine applications is presented. Four major concepts for converting coal into liquid fuels are described: solvent extraction, catalytic liquefaction, pyrolysis, and indirect liquefaction. Data on full range syncrudes, various distillate cuts, and upgraded products are presented for fuels derived from various processes, including H-coal, synthoil, solvent-refined coal, donor solvent, zinc chloride hydrocracking, co-steam, and flash pyrolysis. Some typical ranges of data for coal-derived low Btu gases are also presented
Oportunidad mediante complementariedad: Cómo el Tratado de Libre Comercio en la América del Norte puede beneficiar a México y a los Estados Unidos
Mientras los movimientos regionales en todo el mundo cobran fuerza e influyen en los mercados mundiales, comienza a surgir en las Américas una visión nueva de interdependencia, que requerirá los enfoques transnacionales más innovadores capaces de responder a las diversas necesidades de comunidades grandes y pequeñas, que respeten la raza, la religión y el origen étnico, y que estén preparadas para superar disparidades en el ingreso, la productividad y el bienestar social por medio de la negociación y no del conflicto. Por su parte, las nuevas tecnologías, así como los cambios en el patrón de competitividad, aumentan la presión en favor de las políticas que favorezcan el espíritu de empresa y la empresa competitiva (tanto grande como pequeña), las reformas a la educación y al adiestramiento técnico, mayores investigación y desarrollo, así como la aportación de la infraestructura necesaria. Sólo con la aplicación de estas medidas podrá lograrse la visión de interdependencia. Tratándose de sociedades tan distintas como son las de México y los Estados Unidos, el espacio económico sólo puede vincularse con éxito si la unión económica permite que cada nación refuerce su carácter único. Las relaciones entre poderes desiguales dificultan las negociaciones: los beneficios resultantes de la integración económica deben ser suficientemente extensos para permitir que los vencedores compensen a los perdedores, y la voluntad política debe estar presente para llegar a un compromiso, de manera que quienes de otro modo podrían esperar perder con la integración tengan esperanzas de un futuro mejor. Un “dividendo de la integración” proveniente del comercio y la inversión con México ofrece la mejor esperanza de crecimiento con equidad para toda la América del Norte, siempre que cada uno de los socios esté preparado para hacer las inversiones económicas y sociales apropiadas así como los compromisos políticos adecuados.
Evaluation of subgrid-scale turbulence models using a fully simulated turbulent flow
An exact turbulent flow field was calculated on a three-dimensional grid with 64 points on a side. The flow simulates grid-generated turbulence from wind tunnel experiments. In this simulation, the grid spacing is small enough to include essentially all of the viscous energy dissipation, and the box is large enough to contain the largest eddy in the flow. The method is limited to low-turbulence Reynolds numbers, in our case R sub lambda = 36.6. To complete the calculation using a reasonable amount of computer time with reasonable accuracy, a third-order time-integration scheme was developed which runs at about the same speed as a simple first-order scheme. It obtains this accuracy by saving the velocity field and its first-time derivative at each time step. Fourth-order accurate space-differencing is used
The Effect of Import Substitution on Foreign Exchange Needs, Saving Rates and Growth in Latin America
Algumas implicações do intercâmbio global entre países ricos e pobres: o exemplo dos EUA
Mass seasonal bioflows of high-flying insect migrants
Migrating animals have an impact on ecosystems directly via influxes of predators, prey, and competitors and indirectly by vectoring nutrients, energy, and pathogens. Although linkages between vertebrate movements and ecosystem processes have been established, the effects of mass insect "bioflows" have not been described. We quantified biomass flux over the southern United Kingdom for high-flying (>150 meters) insects and show that ~3.5 trillion insects (3200 tons of biomass) migrate above the region annually. These flows are not randomly directed in insects larger than 10 milligrams, which exploit seasonally beneficial tailwinds. Large seasonal differences in the southward versus northward transfer of biomass occur in some years, although flows were balanced over the 10 year period. Our long-term study reveals a major transport process with implications for ecosystem services, processes, and biogeochemistry
Masses of Neutron Stars in High-Mass X-ray Binaries with Optical Astrometry
Determining the type of matter that is inside a neutron star (NS) has been a
long-standing goal of astrophysics. Despite this, most of the NS equations of
state (EOS) that predict maximum masses in the range 1.4-2.8 solar masses are
still viable. Most of the precise NS mass measurements that have been made to
date show values close to 1.4 solar masses, but a reliable measurement of an
over-massive NS would constrain the EOS possibilities. Here, we investigate how
optical astrometry at the microarcsecond level can be used to map out the
orbits of High-Mass X-ray Binaries (HMXBs), leading to tight constraints on NS
masses. While previous studies by Unwin and co-workers and Tomsick and
co-workers discuss the fact that the future Space Interferometry Mission should
be capable of making such measurements, the current work describes detailed
simulations for 6 HMXB systems, including predicted constraints on all orbital
parameters. We find that the direct NS masses can be measured to an accuracy of
2.5% (1-sigma) in the best case (X Per), to 6.5% for Vela X-1, and to 10% for
two other HMXBs.Comment: 8 pages, Accepted by Ap
Effects of Probiotic (Bifidobacterium longum 35624) Supplementation on Exercise Performance, Immune Modulation, and Cognitive Outlook in Division I Female Swimmers
This work is licensed under a Creative Commons Attribution 4.0 International License.Our aim was to determine the effects of probiotic supplementation (Bifidobacterium longum 35624; 1 billion CFU·d−1) on exercise performance, immune modulation, and cognitive outlook in collegiate female athletes during six weeks of offseason training. Seventeen National Collegiate Athletic Association (NCAA) Division 1 collegiate female swimmers participated in this two-group matched, double-blind, placebo controlled design. Via stratified randomization, participants were assigned to probiotic (B. longum 35624; n = 8) or placebo (n = 9) groups. Pre, mid, and post-training, all participants completed exercise performance testing (aerobic/anaerobic swim time trials and force plate vertical jump) as well as provided serum (cytokine and gastrointestinal inflammatory markers) and salivary immunoglobulin A samples. Recovery-stress questionnaire for athletes (RESTQ-Sport) was administered at baseline and conclusion of each week. Data were analyzed by analysis of covariance (ANCOVA) by time point with the respective baseline values of each dependent variable being the covariate. No significant differences in exercise performance and biochemical markers were observed between groups following offseason training. Recovery-Stress Questionnaire for Athletes (RESTQ-sport) values in B. longum 35624 group had significantly higher (i.e., more desired; p < 0.05) values in sport recovery (weeks five and six) than placebo. Probiotic supplementation in collegiate female swimmers did not affect exercise performance or immune function throughout offseason training, but did indicate alterations in cognitive outlook.Procter & Gamble, Cincinnati, OH, USA gran
“What if There's Something Wrong with Her?”‐How Biomedical Technologies Contribute to Epistemic Injustice in Healthcare
While there is a steadily growing literature on epistemic injustice in healthcare, there are few discussions of the role that biomedical technologies play in harming patients in their capacity as knowers. Through an analysis of newborn and pediatric genetic and genomic sequencing technologies (GSTs), I argue that biomedical technologies can lead to epistemic injustice through two primary pathways: epistemic capture and value partitioning. I close by discussing the larger ethical and political context of critical analyses of GSTs and their broader implications for just and equitable healthcare delivery
The asymmetric radio remnant of SN 1987A
We present seven years of radio observations of SN 1987A made with the
Australia Telescope Compact Array. At 1.4, 2.4, 4.8 and 8.6 GHz, the flux
density of the radio remnant has increased monotonically since emission was
redetected 1200 days after the explosion. On day 3200, the remnant was
expanding at 2800 +/- 400 km/s, which we interpret as indicating significant
deceleration of the fastest moving ejecta. Since day 1787 the spectral index
has remained constant at alpha = -0.95 +/- 0.04. These observations are all
consistent with the shock having encountered a denser, shocked, component of
the progenitor's stellar wind. At the current rate of expansion, the shock is
expected to encounter the inner optical ring in the year 2006 +/- 3.
Using super-resolution, we have also obtained 9 GHz images of the remnant
(resolution approx 0".5) at four epochs. The emission is distributed around the
rim of a near-circular shell, but has become increasingly asymmetric with time.
There are two "hotspots" to the east and west, aligned along the major axis of
the optical ring. This morphology is most likely indicative of an axisymmetric
circumstellar medium into which the shock is expanding, consistent with present
understanding of the progenitor star and its environment.Comment: 45 pages, LaTeX, including 15 PostScript figures. To appear in "The
Astrophysical Journal", volume 479 (20 Apr 1997
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