Compensation Admittance Load Flow: A Computational Tool for the Sustainability of the Electrical Grid

Compensation Admittance Load Flow (CALF) is a power flow analysis method that was developed to enhance the sustainability of the power grid. This method has been widely used in power system planning and operation, as it provides an accurate representation of the power system and its behavior under different operating conditions. By providing a more accurate representation of the power system, it can help identify potential problems and improve the overall performance of the grid. This paper proposes a new approach to the load flow (LF) problem by introducing a linear and iterative method of solving LF equations. The aim is to obtain fast results for calculating nodal voltages while maintaining high accuracy. The proposed CALF method is fast and accurate and is suitable for the iterative calculations required by large energy utilities to solve the problem of quantifying the maximum grid acceptance capacity of new energy from renewable sources and new loads, known as hosting capacity (HC) and load capacity (LC), respectively. Speed and accuracy are achieved through a properly designed linearization of the optimization problem, which introduces the concept of compensation admittance at the node. The proposed method was validated by comparing the results obtained with those coming from state-of-the-art methods

Assessment of a desiccant cooling system in a traditional and innovative nanofluid HVAC system

The topic of energy saving is a constant in everyday life, and it is widespread all over the world. Space heating using solar panels is the most used renewable source of energy, but the application of solar energy for cooling the fluids used for refrigeration is growing very fast. Among the techniques used for refrigeration, this work focused on Desiccant Cooling. In particular, with the use of dynamic simulation software, it was possible to study the heat supplied and the energy consumption of a Heating Ventilation Air Conditioning (HVAC) system of a university building and to compare consumption with those of a Desiccant Cooling system applied to the same building. Four different cases were simulated: two related to the HVAC system, one of which operates with water and glycol and the other one with nanofluid, and the other ones to the Desiccant Cooling system with both types of fluids mentioned above. Keeping the same energy demand of the building in all the simulations, it was found that in summer the Desiccant Cooling system had higher performance than the traditional HVAC system and that the use of the nanofluid in both types of conditioning systems further increased the performance of 21%. Simulations were carried out using TRNSYS software

A STUDY ON THE CONSUMER BEHAVIOUR DURING FESTIVE SEASON IN MALLS

The aim of the study is to find out how the customers behave during festive seasons Christmas, Diwali and New Year in malls. In today’s world there are a lot of promotions and strategies to attract customers. The buying pattern of customers, generally, changes during festive seasons. This study focuses on finding how the customer’s buying pattern varies from normal days to festive days. The conclusion is that further importance has to be given towards improvement of quality of service during festival seasons

The Fractured Imaginary: Popular Thinking on Citizen Soldiers and Warfare in Fifth Century Athens

This dissertation establishes how different citizen soldiers were employed and evaluated in the imaginary of fifth century Athens and gives explanations why popular thinking on military personnel was organised in this way. In so doing it emerges that a particular citizen soldier figured in Athenian conceptions about many aspects of martial activity. Also, it has proven necessary to analyse several other conceptions concerning the waging of war in which military personnel strictly play no part because of their indirect but important influence on how this or that class of Athenian fighters was judged. As a result this study ends up throwing light on the ways in which fifth century Athenians conceived not only of citizen combatants but also of warfare in general. The dissertation begins by outlining the primary sources for the Athenian imaginary and its major characteristics. The numerous tragedies and comedies surviving from the fifth century are shown to be sure evidence for the imaginary and the funeral oration of the period to have had a vital role in the transmission of key elements of Athenian self-identity and their understanding of warfare. Although playwrights and public speakers were invariably members of the Athenian elite, the particular contexts in which they performed compelled them to take up and articulate the values and conceptions of their overwhelmingly non-elite audiences. The imaginary then had a decidedly popular character. It was also a sprawling cultural melange within which incongruous and even patently contradictory ideas could subsist side by side. The second part of this dissertation exposes that the citizen hoplite enjoyed a central and paradigmatic role in the popular thinking of fifth century Athens. It was only ever to the heavily armed soldier that poets and orators turned when they wanted to consider general aspects of warfare, the military obligations of citizenship, and gallant and fainthearted behaviour on the battlefield. The Athenian hoplite also served as the pivotal reference point for the marking out of age and gender distinctions within the city and of the differences in military morality between Greeks and barbarians. Critically, as the prevailing definitions of bravery and cowardice were modelled exclusively on the phalanx warfare of the hoplites, Athenian lightly armed troops, cavalrymen and perhaps even sailors with their very different modes of combat were judged one way or another to be cowardly. Yet the final part of this dissertation demonstrates that this normative status of the heavy infantryman in no way prevented citizen sailors from gaining recognition and positive evaluation of their metier and themselves in the Athenian imaginary of the fifth century. The citizen masses of this period saw their city as the major seapower in the Mediterranean and well understood that its formidable might and security rested on its navy. Fifth century Athenians also had a high regard of seamanship in general and great pride in the naval dominance of their city in particular. Indeed, superlative nautical skills were thought to be 'national' traits of the citizens of imperial Athens which they had enjoyed even in the esteemed age of the heroes. Contemporary citizen sailors themselves were also held to be the saviours of the city and were accorded extraordinary esteem and an exalted status if they perished at sea fighting for Athens. Finally, despite the fact that it directly contradicted their hoplite centred conception of bravery, fifth century Athenians firmly believed that fellow citizens serving as sailors could display gallantry in battle

T-duality for open strings in the presence of backgrounds and noncommutativity

We investigate the effect of T-duality on noncommutativity. Starting with open strings ending on a D2-brane wrapped on a $T^2$ torus in the presence of a Kalb Ramond field, we consider Buscher transformations on the coordinates and background. We find that the dual system is commutative. We also study alternative transformations that can preserve noncommutativity.Comment: In this V3: more references included. Version to appear in J.Phys.

New Penrose Limits and AdS/CFT

We find a new Penrose limit of AdS_5 x S^5 giving the maximally supersymmetric pp-wave background with two explicit space-like isometries. This is an important missing piece in studying the AdS/CFT correspondence in certain subsectors. In particular whereas the Penrose limit giving one space-like isometry is useful for the SU(2) sector of N=4 SYM, this new Penrose limit is instead useful for studying the SU(2|3) and SU(1,2|3) sectors. In addition to the new Penrose limit of AdS_5 x S^5 we also find a new Penrose limit of AdS_4 x CP^3.Comment: 30 page

Divergence Cancellation and Loop Corrections in String Field Theory on a Plane Wave Background

We investigate the one-loop energy shift E to certain two-impurity string states in light-cone string field theory on a plane wave background. We find that there exist logarithmic divergences in the sums over intermediate mode numbers which cancel between the cubic Hamiltonian and quartic ``contact term''. Analyzing the impurity non-conserving channel we find that the non-perturbative, order g_2^2 sqrt(lambda') contribution to E/mu predicted in hep-th/0211220 is in fact an artifact of these logarithmic divergences and vanishes with them, leaving an order g_2^2 lambda' contribution. Exploiting the supersymmetry algebra, we present a form for the energy shift which appears to be manifestly convergent and free of non-perturbative terms. We use this form to argue that E/mu receives order g_2^2 lambda' contributions at every order in intermediate state impurities.Comment: 27 pages; added references, acknowledgments, missing normalization in equations 2.3 - 2.8, also cleaned up notation, and added a few footnote

Integrable Spin Chains on the Conformal Moose

We consider N=1, D=4 superconformal U(N)^{pq} Yang-Mills theories dual to AdS_5xS^5/Z_pxZ_q orbifolds. We construct the dilatation operator of this superconformal gauge theory at one-loop planar level. We demonstrate that a specific sector of this dilatation operator can be thought of as the transfer matrix for a two-dimensional statistical mechanical system, related to an integrable SU(3) anti-ferromagnetic spin chain system, which in turn is equivalent to a 2+1-dimensional string theory where the spatial slices are discretized on a triangular lattice. This is an extension of the SO(6) spin chain picture of N=4 super Yang-Mills theory. We comment on the integrability of this N=1 gauge theory and hence the corresponding three-dimensional statistical mechanical system, its connection to three-dimensional lattice gauge theories, extensions to six-dimensional string theories, AdS/CFT type dualities and finally their construction via orbifolds and brane-box models. In the process we discover a new class of almost-BPS BMN type operators with large engineering dimensions but controllably small anomalous corrections.Comment: 53 pages, 14 eps figures; Added reference

A Transfer Matrix Method for Resonances in Randall-Sundrum Models

In this paper we discuss in detail a numerical method to study resonances in membranes generated by domain walls in Randall-Sundrum-like scenarios. It is based on similar works to understand the quantum mechanics of electrons subject to the potential barriers that exist in heterostructures in semiconductors. This method was used recently to study resonances of a three form field and lately generalized to arbitrary forms. We apply it to a lot of important models, namely those that contain the Gauge, Gravity and Spinor fields. In many cases we find a rich structure of resonances which depends on the parameters involved.Comment: 25 pages, 17 figure