Can the Hagedorn Phase Transition be explained from Matrix Model for Strings?

The partition function of BFSS matrix model is studied for two different classical backgrounds upto 1-loop level. One of the backgrounds correspond to a membrane wrapped around a compact direction and another to a localized cluster of $D0$-branes. It is shown there exist phase transitions between these two configurations - but only in presence of an IR cut-off. The low temperature phase corresponds to a string (wrapped membrane) phase and so we call this the Hagedorn phase transition. While the presence of an IR cut-off seemingly is only required for perturbative analysis to be valid, the physical necessity of such a cut-off can be seen in the dual supergravity side. It has been argued from entropy considerations that a finite size horizon must develop even in an extremal configuration of D0-branes, from higher derivative $O(g_s)$ corrections to supergravity. It can then be shown that the Hagedorn like transition exists in supergravity also. Interestingly the perturbative analysis also shows a second phase transition back to a string phase. This is also reminiscent of the Gregory-Laflamme instability.Comment: minor change

Design and simulation of thin-film silicon quantum well photovoltaic cell

A new thin-film silicon photovoltaic cell could be designed by inserting quantum well layers in the intrinsic region. Calculations show the improvement in spectral absorption due to the quantum well layer insertion. This article reports the design parameters and enhanced spectral absorption for a newly designed thin-film silicon quantum well photovoltaic cell. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/1057

Kinetics and Mechanism of Sulfation Reactions

Roasting of metallic sulfides have been studies by a large number of investigators in recent years. Wadsworth, McCabe in U.S.A. and Smirnov and his group have contrib-uted to our understanding of the roasting mechanism to a very considerable extent. On the basis of these works, two kinds of mechanisms have been proposed for the formation of metallic sulfate from metallic sulfide and oxygen. One of the theory suggests a direct formation of metallic sulfate, whereas the other theory assumes prior formation of metallic oxide of SO2 to SO3, which combines with metallic oxide to give sulfate. Present investigation is aimed at further clearing up the mechanism of sulfate formation and estabilishing the role of individuality of the system on a more generalised basis

Mill House Refractories

Some of the important aspects involved in designing a furnace relate generally to (I) robustness of construction (2) ease of control, (3) ease of maintenance and (4) maximum utilisation of heat energy produced in the furn- ace. With a view to ensuring improved performances, the reheating and heat treatment furnaces are now being designed as complicated and precise units In place of simple bricklined boxes, hitherto employed. The demand on the quality of refractories for application in the different zones of such furnaces have become increasingly stringent

Kinetics and Mechanism of Sulfation Reactions during roasting of Sulfides

ROASTING of sulphidic minerals is one of the very important steps in the extraction metallurgical practice of most of the non-ferrous metals from their concentrates. In recent times, the technique of roasting has undergone substantial changes leading to higher production and better products, more suitable for subsequent operations. Some of these processes have developed on the basis of our understanding of the kinetic limitations of the old proc-esses and elimination of such kinetic bottlenecks like diffusion in the roasting processes. These new processes like flash roasting or fluidized roasting are being increasingly utilised in production units. However, our present state of knowledge on the kinetics of roasting reaction lacks certain fundamental understanding of the process which is explained in the following paragraphs

Magnetic and structural properties of GeMn films: precipitation of intermetallic nanomagnets

We present a comprehensive study relating the nanostructure of Ge_0.95Mn_0.05 films to their magnetic properties. The formation of ferromagnetic nanometer sized inclusions in a defect free Ge matrix fabricated by low temperature molecular beam epitaxy is observed down to substrate temperatures T_S as low as 70 deg. Celsius. A combined transmission electron microscopy (TEM) and electron energy-loss spectroscopy (EELS) analysis of the films identifies the inclusions as precipitates of the ferromagnetic compound Mn_5Ge_3. The volume and amount of these precipitates decreases with decreasing T_S. Magnetometry of the films containing precipitates reveals distinct temperature ranges: Between the characteristic ferromagnetic transition temperature of Mn_5Ge_3 at approximately room temperature and a lower, T_S dependent blocking temperature T_B the magnetic properties are dominated by superparamagnetism of the Mn_5Ge_3 precipitates. Below T_B, the magnetic signature of ferromagnetic precipitates with blocked magnetic moments is observed. At the lowest temperatures, the films show features characteristic for a metastable state.Comment: accepted for publication in Phys. Rev. B 74 (01.12.2006). High resolution images ibide

A simulation model for diarrhoea and other common recurrent infections: a tool for exploring epidemiological methods

The measurement and analysis of common recurrent conditions such as diarrhoea, respiratory infections or fever pose methodological challenges with regard to case definition, disease surveillance and statistical analysis. In this paper we describe a flexible and robust model that can generate simulated longitudinal datasets for a range of recurrent infections, reflecting the stochastic processes that underpin the data collected in the field. It can be used to evaluate and compare alternative disease definitions, surveillance strategies and statistical methods under ‘controlled conditions’. Parameters in the model include: characterizing the distributions of the individual disease incidence and the duration of disease episodes; allowing the average disease duration to depend on an individual's number of episodes (simulating a correlation between incidence and duration); making the individual risk of disease depend on the occurrence of previous episodes (simulating autocorrelation of successive episodes); finally, incorporating seasonal variation of disease

Public-Elite Gap on European Integration: The Missing Link between Discourses about EU Enlargement among Citizens and Elites in Serbia

Enlargement is often regarded as an elite-driven process, which does not or not sufficiently include the views of ordinary citizens. At the same time, support for integration has been eroding over the last decade, contributing to a public-elite gap in preferences towards the process. This paper investigates the relationship between elite and citizens discourses by focusing on Serbia as one of the candidate countries. The case of a candidate country is interesting, as domestic elites need to obtain the support from citizens in making the EU-driven transformations, whereas citizens may be critical to some of the imposed reforms. This may push and pull both groups in the opposite directions, increasing the public-elite gap on European integration. This contribution supplements previous research, which identified discourses among citizens in Serbia, with an analysis of media content. Using vignettes for each discourse found among citizens, the contents of statements in two major Serbian newspapers have been coded. The analysis shows that all four citizen discourses are represented in media. The discourse favoring Serbia’s accession enjoys best representation in the media, reflecting views of Serbia’s political elite. In contrast, the narrative rejecting Serbia’s integration in the EU finds the least space in newspapers, while the remaining two discourses share almost an equal media representation. Most importantly, we find that approximately one fourth of media content does not fit any of the four citizen discourses. This demonstrates not only the size, but also the substance of the public-elite gap on European integration in Serbia. The public-elite gap illustrated here tilts the political debate in Serbia towards one with rather supportive expectations of enlargement and integration. At the same time, we noted that more critical views among citizens are not, or not yet, reflected in the media, while the media is reporting on issues that do not resonate with citizens’ views. A question is whether this is a sustainable route, and whether political ‘entrepreneurs’ will capitalize on these views in order to build alternative political platforms in Serbian politics or influence Serbia’s progress.Seventh Framework Programme (FP7)320115The politics and administration of institutional chang

A model for hedging load and price risk in the Texas electricity market

Energy companies with commitments to meet customers’ daily electricity demands face the problem of hedging load and price risk. We propose a joint model for load and price dynamics, which is motivated by the goal of facilitating optimal hedging decisions, while also intuitively capturing the key features of the electricity market. Driven by three stochastic factors including the load process, our power price model allows for the calculation of closed-form pricing formulas for forwards and some options, products often used for hedging purposes. Making use of these results, we illustrate in a simple example the hedging benefit of these instruments, while also evaluating the performance of the model when fitted to the Texas electricity market