Thermodynamics of Finite Quantum Systems: Application to Spin Magnetism II

We extend our study of thermodynamics of a Kubo particle to temperatures smaller than the interlevel spacing. We obtain the distribution functions of spin susceptibility and heat capacity for Poisson and Wigner-Dyson level statistics. We evaluate the line shape of the Knight shift due to spin effects both in a single particle and for the ensemble average and compare it with orbital and spin-orbit contributions.Comment: 20 pages (16 text, 4 figures) uu-encoded, z-compressed PostScript. Latest versions of manuscripts available at http://physuna.phs.uc.edu/professors/serota.html or by e-mail, by request from [email protected]

The measurement of the winds near the ocean surface with a radiometer-scatterometer on Skylab

The author has identified the following significant results. There were a total of twenty-six passes in the ZLV mode that yielded useful data. Six were in the in-track noncontiguous mode; all others were in the cross-track noncontiguous mode. The wind speed and direction, as effectively determined in a neutral atmosphere at 19.5 m above the sea surface, were found for each cell scanned by S193. It is shown how the passive microwave measurements were used both to compute the attenuation of the radar beam and to determine those cells where the backscatter measurement was suspect. Given the direction of the wind from some independent source, with the typical accuracy of measurement by available meteorological methods, a backscatter measurement at a nadir angle of 50, 43, or 32 deg can be used to compute the speed of the wind averaged over the illuminated area

Importance of the Doppler Effect to the Determination of the Deuteron Binding Energy

The deuteron binding energy extracted from the reaction ${}^1H(n,\gamma){}^2H$ is reviewed with the exact relativistic formula, where the initial kinetic energy and the Doppler effect are taken into account. We find that the negligible initial kinetic energy of the neutron could cause a significant uncertainty which is beyond the errors available up to now. Therefore, we suggest an experiment which should include the detailed informations about the initial kinetic energy and the detection angle. It could reduce discrepancies among the recently reported values about the deuteron binding energy and pin down the uncertainty due to the Doppler broadening of $\gamma$ ray.Comment: 5 page

Challenges to comsumer protection legislation in tourism contexts

Many destinations worldwide have enacted laws to protect consumers in general but which have relevance to tourists as consumers and thus destination competitiveness. The impact of any such consumer protection, however, is limited by certain complexities that erode consumer confidence within tourism contexts. These relate to unstable tourism environments, the changing dynamics of the travel services chain, growing product complexity, information failures, changes in consumer values, and technological change. Examples are provided of consumer laws relevant to each of these important features of tourism. Issues for further research into the links between consumer protection legislation and destination competitiveness are discussed

General dynamical equations of motion for elastic body systems

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/76290/1/AIAA-11407-643.pd

Holographic Magnetic Star

A warm fermionic AdS star under a homogeneous magnetic field is explored. We obtain the relativistic Landau levels by using Dirac equation and use the Tolman-Oppenheimer-Volkoff (TOV) equation to study the physical profiles of the star. Bulk properties such as sound speed, adiabatic index, and entropy density within the star are calculated analytically and numerically. Bulk temperature increases the mass limit of the AdS star but external magnetic field has the opposite effect. The results are partially interpreted in terms of the pre-thermalization process of the gauge matter at the AdS boundary after the mass injection. The entropy density is found to demonstrate similar temperature dependence as the magnetic black brane in the AdS in certain limits regardless of the different nature of the bulk and Hawking temperatures. Total entropy of the AdS star is also found to be an increasing function of the bulk temperature and a decreasing function of the magnetic field, similar behaviour to the mass limit. Since both total entropy and mass limit are global quantities, they could provide some hints to the value of entropy and energy of the dual gauge matter before and during the thermalization.Comment: 39 pages, 14 figures, 1 table, comments and references added, to appear in JHE

The road travelled : after main‐group elements as transition metals

Since the latter quarter of the twentieth century, main group chemistry has undergone significant advances. Power's timely review in 2010 highlighted the inherent differences between the lighter and heavier main group elements, and that the heavier analogues resemble transition metals as shown by their reactivity towards small molecules. In this concept article, we present an overview of the last 10 years since Power's seminal review, and the progress made for catalytic application. This examines the use of low oxidation state and/or low coordinate group 13 and 14 complexes towards small molecule activation (oxidative addition step in a redox based cycle) and how ligand design plays a crucial role in influencing subsequent reactivity. The challenge in these redox based catalytic cycles still centres on the main group complexes’ ability to undergo reductive elimination, however considerable progress in this field has been reported via reversible oxidative addition reactions. Within the last 5 years the first examples of well‐defined low valent main group catalysts have begun to emerge, representing a bright future ahead for main group chemistry

Boosting the petrochronology arsenal: REE partitioning between garnet and monazite in Bhutanese pelitic metasediments

Metamorphic studies are increasingly striving to integrate timing information with petrographic analysis and thermobarometry – the developing field of petrochronology. Recent advances in analytical techniques, in particular a variety of in situ methods that can potentially extract the information preserved in disequilibrium features, have reinvigorated metamorphic studies. The strength of petrochronology lies in linking the isotopic age directly to the metamorphic stage, in contrast to earlier studies where accessory phase ages existed in isolation from the thermobaromatric data with which they were tentatively linked. Garnet has proved itself an invaluable tool in metamorphic studies, yielding microstructural, thermobarometric, geochemical and even geochronological information. Although common in amphibolite-facies pelitic metasediments, garnet does not easily yield its chronological data, so the common accessory phase monazite has been used more routinely. Typically, monazite isotopic ages cannot be linked to the development of different metamorphic assemblages because their textural relationships, especially with fabric-forming phases, are commonly obscure. However, their distribution as matrix grains versus inclusions in porphyroblast minerals such as garnet, or in retrograde textures, can yield useful information. In situ investigations of chemical zoning in both monazite and garnet offer the potential to link crystallisation of the two minerals more closely. Since both monazite and garnet incorporate rare earth elements (REE), their equilibrium partitioning behaviour provides not only a useful test of equilibration, but also a way of linking time to temperature. Previously reported garnetmonazite partitioning data record the behaviour expected under granulite-facies (>750°C) conditions. We document REE concentration data from sub-solidus amphibolite-facies (~650-700°C) rocks from the eastern Himalaya (Bhutan), where age and inclusion relationships suggest that garnet and monazite grew simultaneously. The garnet/monazite ratios show steeper heavy REE patterns than those reported from the higher-temperature experimental data. These data suggest either that the partitioning relationships vary with temperature, or that different relationships hold in sub-solidus vs. supra-solidus rocks. Bhutan is an excellent location to test these relationships; abundant pelitic metasediments within a single tectonic unit span metamorphic grades ranging from sub-solidus to supra-solidus. Moreover, these metamorphic rocks (and their counterparts along the strike of the orogen) have been extensively studied in recent years both in terms of their metamorphism and their monazite geochronology, providing an ideal framework for petrochronological research with applications to all major orogens

On Virtual Displacement and Virtual Work in Lagrangian Dynamics

The confusion and ambiguity encountered by students, in understanding virtual displacement and virtual work, is discussed in this article. A definition of virtual displacement is presented that allows one to express them explicitly for holonomic (velocity independent), non-holonomic (velocity dependent), scleronomous (time independent) and rheonomous (time dependent) constraints. It is observed that for holonomic, scleronomous constraints, the virtual displacements are the displacements allowed by the constraints. However, this is not so for a general class of constraints. For simple physical systems, it is shown that, the work done by the constraint forces on virtual displacements is zero. This motivates Lagrange's extension of d'Alembert's principle to system of particles in constrained motion. However a similar zero work principle does not hold for the allowed displacements. It is also demonstrated that d'Alembert's principle of zero virtual work is necessary for the solvability of a constrained mechanical problem. We identify this special class of constraints, physically realized and solvable, as {\it the ideal constraints}. The concept of virtual displacement and the principle of zero virtual work by constraint forces are central to both Lagrange's method of undetermined multipliers, and Lagrange's equations in generalized coordinates.Comment: 12 pages, 10 figures. This article is based on an earlier article physics/0410123. It includes new figures, equations and logical conten

Skylab S-193 Radscat microwave measurements of sea surface winds

The S-193 Radscat made extensive measurements of many sea conditions. Measurements were taken in a tropical hurricane (Ava), a tropical storm (Christine), and in portions of extratropical cyclones. Approximately 200 scans of ocean data at 105 kilometer spacings were taken during the first two Skylab missions and another 200 during the final mission when the characteristics of the measurements changed due to damage of the antenna. Backscatter with four transmit/receive polarization combinations and emissions with horizontal and vertical receive polarizations were measured. Other surface parameters investigated for correlation with the measurements included sea temperature, air/sea temperature difference, and gravity-wave spectrum. Methods were developed to correct the microwave measurements for atmospheric effects. The radiometric data were corrected accurately for clear sky and light cloud conditions only. The radiometer measurements were used to recover the surface scattering characteristics for all atmospheric conditions excluding rain. The radiometer measurements also detected the presence of rain which signaled when the scattering measurement should not be used for surface wind estimation. Regression analysis was used to determine empirically the relation between surface parameters and the microwave measurements, after correction for atmospheric effects. Results indicate a relationship approaching square-law at 50 deg between differential scattering coefficient and wind speed with horizontally polarized scattering data showing slightly more sensitivity to wind speed than vertically polarized data