Dirac equation in spacetimes with torsion and non-metricity

Dirac equation is written in a non-Riemannian spacetime with torsion and non-metricity by lifting the connection from the tangent bundle to the spinor bundle over spacetime. Foldy-Wouthuysen transformation of the Dirac equation in a Schwarzschild background spacetime is considered and it is shown that both the torsion and non-metricity couples to the momentum and spin of a massive, spinning particle. However, the effects are small to be observationally significant.Comment: 12 pages LATEX file, no figures, to appear in Int. J. Mod. Phys.

Transport coefficients of a mesoscopic fluid dynamics model

We investigate the properties of stochastic rotation dynamics (Malevanets-Kapral method), a mesoscopic model used for simulating fluctuating hydrodynamics. Analytical results are given for the transport coefficients. We discuss the most efficient way of measuring the transport properties and obtain excellent agreement between the theoretical and numerical calculations.Comment: 12 pages, 9 figures, submitted to J. Chem. Phy

Soft X-ray Emission from the Spiral Galaxy NGC 1313

The nearby barred spiral galaxy NGC 1313 has been observed with the PSPC instr- ument on board the ROSAT X-ray satellite. Ten individual sources are found. Three sources (X-1, X-2 and X-3 [SN~1978K]) are very bright (~10^40 erg/s) and are unusual in that analogous objects do not exist in our Galaxy. We present an X-ray image of NGC~1313 and \xray spectra for the three bright sources. The emission from the nuclear region (R ~< 2 kpc) is dominated by source X-1, which is located ~1 kpc north of the photometric (and dynamical) center of NGC~1313. Optical, far-infrared and radio images do not indicate the presence of an active galactic nucleus at that position; however, the compact nature of the \xray source (X-1) suggests that it is an accretion-powered object with central mass M >~ 10^3 Msun. Additional emission (L_X ~ 10^39 erg/s) in the nuclear region extends out to ~2.6 kpc and roughly follows the spiral arms. This emission is from 4 sources with luminosity of several x 10^38 erg/s, two of which are consistent with emission from population I sources (e.g., supernova remnants, and hot interstellar gas which has been heated by supernova remnants). The other two sources could be emission from population II sources (e.g., low-mass \xray binaries). The bright sources X-2 and SN~1978K are positioned in the southern disk of NGC~1313. X-2 is variable and has no optical counterpart brighter than 20.8 mag (V-band). It is likely that it is an accretion-powered object in NGC~1313. The type-II supernova SN~1978K (Ryder \etal 1993) has become extra- ordinarily luminous in X-rays $\sim$13 years after optical maximum.Comment: to appear in 10 Jun 1995 ApJ, 30 pgs uuencoded compressed postscript, 25 pgs of figures available upon request from colbert, whole preprint available upon request from Sandy Shrader ([email protected]), hopefully fixed unknown problem with postscript fil

Geomorphological Processes Associated with an Ice-Marginal Lake at Bridge Glacier, British Colombia

Four well-defined strandlines mark the former extent and drawdown phases of an ice-marginal lake that was impounded by Bridge Glacier during the Little Ice Age. 14C dates, tree-ring counts and historic air photographs indicate that the lake stood at the highest strandline (L1) for about 550 years, and at the lower strandlines for only a few decades in total. Estimates of rates for geomorphic processes are based on absolute chronology, ground measurements and photogrammetry: benches along L1 may have been cut into bedrock and till at rates of about 3.6 and 7.3 cm yr~1 respectively; a spillway channel was incised into a lateral moraine at 2.2 m yr\ and mean bedload transport to a delta from a 6.25 km2 ice-covered sub-basin was about 945 m3 yr '. Major floods from the stable, rock-cut spillway of the highest lake, that may have been caused by temporary damming of the lake outlet by snowbanks or lake ice, constructed a large fan on the main Bridge Glacier outwash apron. The lower lakes probably drained catastrophically due to failure of moraine and ice dams, but the resulting floods were rapidly attenuated downstream.Quatre lignes de rivage bien définies montrent l'étendue d'un lac juxta-glaciaire retenu par le glacier Bridge pendant le Petit Âge glaciaire. Des datations au radiocarbone, des comptages de cernes annuels et l'analyse d'anciennes photos aériennes démontrent que le lac s'est maintenu au niveau correspondant à la plus haute ligne de rivage (L1) pendant environ 550 ans, et aux niveaux inférieurs pendant tout au plus quelques décennies. Les vitesses associées aux processus géomorphologiques sont fondées sur la chronologie absolue, les levés de terrain et la photogrammétrie. Les banquettes le long du rivage L1 ont peut-être été entaillées dans la roche et le till à des taux d'environ 3,6 et 7,3 cm a-1 respectivement; un chenal déversoir a incisé la moraine latérale à une vitesse de 2,2 m a-1 et le transport de la charge de fond provenant d'un sous-bassin englacé de 6,45 km2 vers un delta s'est fait à une vitesse moyenne d'environ 945 m3 a-1. Des crues majeures débouchant du chenal déversoir associé au niveau lacustre supérieur ont construit un grand cône alluvial sur la principale plaine d'épandage fluvioglaciaire. Ces crues ont probablement été causées par les endiguements temporaires de l'exutoire par des congères ou des embâcles. Les lacs des niveaux inférieurs se sont probablement vidangés de façon brutale en raison de la rupture des barrages morainiques ou glaciaires, mais les crues qui en ont résulté ont vite été atténuées en aval.Vier klar abgegrenzte Uferlinien markieren die ehemalige Ausdehnung und die Rùckzugsphasen eines glazialen Randsees, der wàhrend der Kleinen Eiszeit durch den Bridge-Gletscher eingesperrt war. 14C-Daten, dendrochronologische Zàhlungen und historische Luftaufnahmen zeigen, dass der See ungefàhr 550 Jahre lang die hochste Uferlinie einnahm (L1) und insgesamt nur einige Jahrzehnte lang die niedrigeren Uferlinien. Die Schàtzungen der Geschwindigkeit der geomorphologischen Prozesse stûtzen sich auf die absolute Chronologie, Bodenabmes-sungen und Photogrammétrie: Leisten entlang L1 sind wahrscheinlich in anstehendes Gestein und Till mit einer Rate von etwa 3,6 bzw. 7,3 cm Jahr1 eingeschnitten worden; ein Ablasskanal wurde in eine seitliche Moràne mit einer Geschwindigkeit von 2,2 m Jahr' eingeschnitten, und der durchschnittliche Transport der Sedimentfracht von einem 6,25 km2 grossen eisbedeckten Unterbecken zu einem Delta war etwa 945 m3 Jahr-1. Grôssere Hochfluten von dem festen in den FeIs geschnittenen Ablasskanal des hôchstgelegenen Sees, die môglicherweise durch vorùbergehende Eindâmmung des See-Ausflusses durch Schneebânke oder Seeeis bewirkt wurden, formten einen breiten Alluvialfâcher auf der glazialen Haupt-schwemmebene des Bridge-Gletschers. Die niedriger gelegenen Seen haben sich wahrscheinlich katastrophenartig geleert aufgrund des Zusammenbruchs von Morânenund Eisdâmmen, doch wurden die entstandenen Fluten stromabwàrts schnell gemildert

Alien Registration- Ryder, Harry M. (Mars Hill, Aroostook County)

https://digitalmaine.com/alien_docs/33952/thumbnail.jp

Modeling microscopic swimmers at low Reynolds number

We employ three numerical methods to explore the motion of low Reynolds number swimmers, modeling the hydrodynamic interactions by means of the Oseen tensor approximation, lattice Boltzmann simulations and multiparticle collision dynamics. By applying the methods to a three bead linear swimmer, for which exact results are known, we are able to compare and assess the effectiveness of the different approaches. We then propose a new class of low Reynolds number swimmers, generalized three bead swimmers that can change both the length of their arms and the angle between them. Hence we suggest a design for a microstructure capable of moving in three dimensions. We discuss multiple bead, linear microstructures and show that they are highly efficient swimmers. We then turn to consider the swimming motion of elastic filaments. Using multiparticle collision dynamics we show that a driven filament behaves in a qualitatively similar way to the micron-scale swimming device recently demonstrated by Dreyfus et al.Comment: 12 pages, 10 figure

From Reciprocity to Interdependence: Mass Incarceration and Service-Learning

This essay considers the difficulty of seeing systems of oppression—a challenging first step of writing for social change. I argue that service-learning faculty and public writing scholars have relied on outdated ways of thinking about racism and oppression, treating social issues as isolated instances of discrimination. Instead, by drawing from Michelle Alexander’s The New Jim Crow, I argue that we need to recognize that mass incarceration has created a new a racial caste system and is the root cause uniting many social problems. Mass incarceration and neoliberalism work together to exclude millions of people from economic and civic life, stain them with moral condemnation so that they remain invisible to the majority, and divert public attention from the flaws in our political and economic structures. I use examples from a local nonprofit to illustrate how this framework offers a new approach to servicelearning and public writing

Superfluid Helium Orbital Resupply Coupling

The resupply of superfluid helium to satellites and other space-based experiment packages can increase the useful longevity of these devices far beyond their present life expectancies which are many times determined by the supply of helium coolant. The transfer of superfluid helium to spacecraft in space will require a reusable coupling that functions at 1.8 Kelvin with little heat leak and low pressure drop. Moog has designed the Helium Resupply Coupling to meet these operational requirements. Initially, the coupling manual mode operation will be demonstrated on orbit by an EVA crew member during the Space Shuttle borne Superfluid Helium On-Orbit Transfer (SHOOT) experiment. The ultimate application will use robotic (automatic) coupling operation to which the present design readily adapts. The utilization of Moog's exclusive Rotary Shut-Off (RSO) technology in the development of the Superfluid Helium Resupply Coupling is described. The coupling not only performs the function of a flow control valve and disconnect but also provides adequate safety features for a shuttle launched man-rated payload. In addition, the coupling incorporates the necessary features to provide the high thermal isolation of the internal flow path from the external environment